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Benitez R, Caro M, Andres-Leon E, O'Valle F, Delgado M. CORTISTATIN REGULATES FIBROSIS AND MYOFIBROBLAST ACTIVATION IN EXPERIMENTAL HEPATOTOXIC- AND CHOLESTATIC-INDUCED LIVER INJURY. Br J Pharmacol 2021; 179:2275-2296. [PMID: 34821378 DOI: 10.1111/bph.15752] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 10/08/2021] [Accepted: 11/08/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Liver fibrosis induced by chronic hepatic injury remains as a major cause of morbidity and mortality worldwide. Identification of susceptibility/prognosis factors and new therapeutic tools for treating hepatic fibrotic disorders are urgent medical needs. Cortistatin is a neuropeptide with potent anti-inflammatory and anti-fibrotic activities in lung that binds to receptors that are expressed in liver fibroblasts and hepatic stellate cells. We evaluated the capacity of cortistatin to regulate liver fibrosis. EXPERIMENTAL APPROACH We experimentally induced liver fibrosis in mice by chronic CCl4 exposition and bile duct ligation and evaluated the histopathological signs and fibrotic markers. KEY RESULTS Hepatic expression of cortistatin inversely correlated with liver fibrosis grade in mice and humans with hepatic disorders. Cortistatin-deficient mice showed exacerbated signs of liver damage and fibrosis and increased mortality rates when challenged to hepatotoxic and cholestatic injury. Compared to wild-type mice, non-parenchymal liver cells isolated from cortistatin-deficient mice showed increased presence of cells with activated myofibroblast phenotypes and a differential genetic signature that is indicative of activated hepatic stellate cells and periportal fibroblasts and of myofibroblasts with active contractile apparatus. Cortistatin treatment reversed in vivo and in vitro these exaggerated fibrogenic phenotypes and protected from progression to severe liver fibrosis in response to hepatic injury. CONCLUSION AND IMPLICATIONS We identify cortistatin as an endogenous molecular break of liver fibrosis and its deficiency as a potential poor-prognosis marker for chronic hepatic disorders that course with fibrosis. Cortistatin-based therapies emerge as attractive strategies for ameliorating severe hepatic fibrosis of various etiologies.
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Affiliation(s)
- Raquel Benitez
- Institute of Parasitology and Biomedicine Lopez-Neyra, PT Salud, Granada, Spain
| | - Marta Caro
- Institute of Parasitology and Biomedicine Lopez-Neyra, PT Salud, Granada, Spain
| | - Eduardo Andres-Leon
- Institute of Parasitology and Biomedicine Lopez-Neyra, PT Salud, Granada, Spain
| | - Francisco O'Valle
- Dept. of Pathology, School of Medicine, IBIMER and IBS-Granada, University of Granada, Spain
| | - Mario Delgado
- Institute of Parasitology and Biomedicine Lopez-Neyra, PT Salud, Granada, Spain
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Therapeutic Potential of Cucumis melo (L.) Fruit Extract and Its Silver Nanopartciles Against DEN-Induced Hepatocellular Cancer in Rats. Appl Biochem Biotechnol 2021; 194:368-381. [PMID: 34792748 DOI: 10.1007/s12010-021-03765-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 11/08/2021] [Indexed: 10/19/2022]
Abstract
Biosynthesized silver nanoparticles have a wide range of biological activities and using nanoparticles as one of the novel approaches in cancer therapy. In this present research work, the anti-cancer efficacy of Cucumis melo fruit extract and its silver nanoparticles was explored. Wistar rats were divided into six groups and hepatic cancer was induced with 0.01% DEN (diethylnitrosamine) through drinking water for 16 weeks. Cyclophosphamide was given as the standard drug at the dose of 50 mg/kg body weight. Hematological parameters showed a decrease in the levels of hemoglobin (Hb), packed cell volume (PCV), red blood cells (RBC), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), and platelets (PLTS) levels except white blood cell (WBC) in DEN-induced cancer animals. Significant alterations in the hematological parameters were observed after treatment which indicate the protective effect of Cucumis melo fruit on the hemopoietic system. The structural integrity of the cells has been damaged in cancer-induced animals, and this results in cytoplasmic leakage of enzyme into the blood stream, leads to the elevated levels of these enzymes in blood with subsequent fall in the tissues. Hence, the levels of liver function markers such as AST ALT, ALP, LDH, GGT, and 5'NT were significantly elevated in serum and the liver of cancer-induced rats. The levels of serum tumor markers, viz., alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA), elevated in rats induced with DEN, which then were reduced following Cucumis melo fruit treatment, indicating the anti-cancer activity of the drug. Histological evaluation of the liver and kidney was also performed to authenticate the present work. Treatment with crude extract and silver nanoparticles of Cucumis melo fruit indicates that Cucumis melo fruit could have exerted its protective effect.
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Kimura T, Singh S, Tanaka N, Umemura T. Role of G Protein-Coupled Receptors in Hepatic Stellate Cells and Approaches to Anti-Fibrotic Treatment of Non-Alcoholic Fatty Liver Disease. Front Endocrinol (Lausanne) 2021; 12:773432. [PMID: 34938271 PMCID: PMC8685252 DOI: 10.3389/fendo.2021.773432] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022] Open
Abstract
The prevalence of non-alcoholic fatty liver disease (NAFLD) is globally increasing. Gaining control over disease-related events in non-alcoholic steatohepatitis (NASH), an advanced form of NAFLD, is currently an unmet medical need. Hepatic fibrosis is a critical prognostic factor in NAFLD/NASH. Therefore, a better understanding of the pathophysiology of hepatic fibrosis and the development of related therapies are of great importance. G protein-coupled receptors (GPCRs) are cell surface receptors that mediate the function of a great variety of extracellular ligands. GPCRs represent major drug targets, as indicated by the fact that about 40% of all drugs currently used in clinical practice mediate their therapeutic effects by acting on GPCRs. Like many other organs, various GPCRs play a role in regulating liver function. It is predicted that more than 50 GPCRs are expressed in the liver. However, our knowledge of how GPCRs regulate liver metabolism and fibrosis in the different cell types of the liver is very limited. In particular, a better understanding of the role of GPCRs in hepatic stellate cells (HSCs), the primary cells that regulate liver fibrosis, may lead to the development of drugs that can improve hepatic fibrosis in NAFLD/NASH. In this review, we describe the functions of multiple GPCRs expressed in HSCs, their roles in liver fibrogenesis, and finally speculate on the development of novel treatments for NAFLD/NASH.
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Affiliation(s)
- Takefumi Kimura
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
- Department of Internal Medicine, Division of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
- *Correspondence: Takefumi Kimura, ; ; Naoki Tanaka,
| | - Simran Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | - Naoki Tanaka
- International Relations Office, Shinshu University School of Medicine, Matsumoto, Japan
- *Correspondence: Takefumi Kimura, ; ; Naoki Tanaka,
| | - Takeji Umemura
- Department of Internal Medicine, Division of Gastroenterology, Shinshu University School of Medicine, Matsumoto, Japan
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Somatostatin as Inflow Modulator in Liver-transplant Recipients With Severe Portal Hypertension. Ann Surg 2019; 269:1025-1033. [DOI: 10.1097/sla.0000000000003062] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Hessheimer AJ, Martínez de la Maza L, Adel Al Shwely F, Espinoza AS, Ausania F, Fondevila C. Somatostatin and the "Small-For-Size" Liver. Int J Mol Sci 2019; 20:2512. [PMID: 31121844 PMCID: PMC6566601 DOI: 10.3390/ijms20102512] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/07/2019] [Accepted: 05/14/2019] [Indexed: 02/07/2023] Open
Abstract
"Small-for-size" livers arising in the context of liver resection and transplantation are vulnerable to the effects of increased portal flow in the immediate postoperative period. Increased portal flow is an essential stimulus for liver regeneration. If the rise in flow and stimulus for regeneration are excessive; however, liver failure and patient death may result. Somatostatin is an endogenous peptide hormone that may be administered exogenously to not only reduce portal blood flow but also offer direct protection to different cells in the liver. In this review article, we describe key changes that transpire in the liver following a relative size reduction occurring in the context of resection and transplantation and the largely beneficial effects that peri-operative somatostatin therapy may help achieve in this setting.
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Affiliation(s)
- Amelia J Hessheimer
- Hepatopancreatobiliary Surgery and Transplantation, General & Digestive Surgery, Metabolic & Digestive Diseases Institute (ICMDM), Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona, 08036 Barcelona, Spain.
| | - Lilia Martínez de la Maza
- Hepatopancreatobiliary Surgery and Transplantation, General & Digestive Surgery, Metabolic & Digestive Diseases Institute (ICMDM), Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona, 08036 Barcelona, Spain.
| | - Farah Adel Al Shwely
- Hepatopancreatobiliary Surgery and Transplantation, General & Digestive Surgery, Metabolic & Digestive Diseases Institute (ICMDM), Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona, 08036 Barcelona, Spain.
| | - Arlena Sofía Espinoza
- Hepatopancreatobiliary Surgery and Transplantation, General & Digestive Surgery, Metabolic & Digestive Diseases Institute (ICMDM), Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona, 08036 Barcelona, Spain.
| | - Fabio Ausania
- Hepatopancreatobiliary Surgery and Transplantation, General & Digestive Surgery, Metabolic & Digestive Diseases Institute (ICMDM), Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona, 08036 Barcelona, Spain.
| | - Constantino Fondevila
- Hepatopancreatobiliary Surgery and Transplantation, General & Digestive Surgery, Metabolic & Digestive Diseases Institute (ICMDM), Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona, 08036 Barcelona, Spain.
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Lu YY, Gao JH, Zhao C, Wen SL, Tang CW, Wang YF. Cyclooxygenase-2 up-regulates hepatic somatostatin receptor 2 expression. Sci Rep 2018; 8:11033. [PMID: 30038293 PMCID: PMC6056476 DOI: 10.1038/s41598-018-29349-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 07/09/2018] [Indexed: 02/05/2023] Open
Abstract
Somatostatin and its analogues, which function by binding to somatostatin receptors (SSTRs) 1-5, play a protective role in liver cirrhosis. Hepatic SSTR-2 expression is up-regulated in subjects with liver cirrhosis. However, little is known about the mechanisms underlying this process. In the present study, we observed the up-regulation of hepatic SSTR-2 expression in thioacetamide (TAA)-induced cirrhotic rats and further showed that cyclooxygenase-2 (COX-2) might play a role in this process via the protein kinase C (PKC)-cAMP response element binding protein (CREB) signaling pathway. In vivo, the up-regulated SSTR-2 in liver cirrhosis was inhibited by the addition of a selective COX-2 inhibitor, such as celecoxib. In vitro, the up-regulation of COX-2 by either transfection with COX-2 plasmids or treatment with TAA increased levels of SSTR-2 and phosphorylated CREB (p-CREB) in the human hepatocyte cell line L02. Furthermore, the increase in SSTR-2 expression was inhibited by the addition of celecoxib and a PKC inhibitor. Moreover, for comparable DNA methylation levels in the region upstream of the hepatic SSTR-2 gene in normal and cirrhotic livers, DNA methylation may not contribute to the up-regulation of SSTR-2 expression in cirrhotic livers. In conclusion, the up-regulation of hepatic SSTR-2 might be induced by COX-2 via the PKC-CREB signaling pathway but is probably not induced by DNA methylation.
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Affiliation(s)
- Yao-Yao Lu
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Jin-Hang Gao
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, China.,Division of Digestive Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Chong Zhao
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.,Division of Digestive Diseases, West China Hospital, Sichuan University, Chengdu, China
| | - Shi-Lei Wen
- Department of Human Anatomy, Academy of Preclinical and Forensic Medicine, West China Medicine College, Sichuan University, Chengdu, China
| | - Cheng-Wei Tang
- Division of Peptides Related with Human Diseases, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China. .,Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, China. .,Division of Digestive Diseases, West China Hospital, Sichuan University, Chengdu, China.
| | - Yu-Fang Wang
- Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, China.
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Dufourny L, Delmas O, Teixeira-Gomes AP, Decourt C, Sliwowska JH. Neuroanatomical connections between kisspeptin neurones and somatostatin neurones in female and male rat hypothalamus: a possible involvement of SSTR1 in kisspeptin release. J Neuroendocrinol 2018; 30:e12593. [PMID: 29543369 DOI: 10.1111/jne.12593] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/09/2018] [Indexed: 01/23/2023]
Abstract
Somatostatin (SST) a neuropeptide involved in the central modulation of several physiological functions, is co-distributed in the same hypothalamic areas as kisspeptin (KP), the most potent secretagogue of the gonadotropin-releasing hormone (GnRH) secretion known to date. As SST infused intracerebroventricularly (icv) evoked a potent inhibition of GnRH release, we explored neuroanatomical relationships between KP and SST populations in male and female rats. For that, intact males and ovariectomised oestradiol-replaced females were killed and their brains processed in order to simultaneously detect KP, SST and synapsin, a marker for synapses. We observed numerous appositions of KP on SST neurones both in female and male arcuate nucleus (ARC) and ventromedial hypothalamus. A large association between SST terminals and KP neurones at the level of the pre-optic area (POA) was also observed in female rats and in a more limited frame in males. Finally, most KP neurones from the ARC showed SST appositions in both sexes. To determine whether SST could affect KP cell activity, we assessed whether SST receptors (SSTR) were present on KP neurones in the ARC. We also looked for the presence of SSTR1 and SSTR2A in the brain of male rats. Brains were processed through a sequential double immunocytochemistry in order to detect KP and SSTR1 or KP and SSTR2A. We observed overlapping distributions of immunoreactive neurones for SSTR1 and KP and counted approximately one third of KP neurones with SSTR1. In contrast, neurones labelled for SSTR2A or KP were often juxtaposed in the ARC and the occurrence of double-labelled neurones was sporadic (<5%). These results suggest that SST action on KP neurones would pass mainly through SSTR1 at the level of the ARC. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Laurence Dufourny
- UMR85 Physiologie de la Reproduction et des Comportements, F-37380, Nouzilly, France
- CNRS, UMR 7247, F-37380, Nouzilly, France
- Université de Tours, F-37041, Tours, France
- IFCE, F-37380, Nouzilly, France
| | - Oona Delmas
- UMR85 Physiologie de la Reproduction et des Comportements, F-37380, Nouzilly, France
- CNRS, UMR 7247, F-37380, Nouzilly, France
- Université de Tours, F-37041, Tours, France
- IFCE, F-37380, Nouzilly, France
| | - Ana-Paula Teixeira-Gomes
- UMR85 Physiologie de la Reproduction et des Comportements, F-37380, Nouzilly, France
- CNRS, UMR 7247, F-37380, Nouzilly, France
- Université de Tours, F-37041, Tours, France
- IFCE, F-37380, Nouzilly, France
- INRA UMR INRA 1282 Infectiologie et Santé Publique, Université François Rabelais, F-37380, Nouzilly, France
| | - Caroline Decourt
- UMR85 Physiologie de la Reproduction et des Comportements, F-37380, Nouzilly, France
- CNRS, UMR 7247, F-37380, Nouzilly, France
- Université de Tours, F-37041, Tours, France
- IFCE, F-37380, Nouzilly, France
| | - Joanna H Sliwowska
- Lab. of Neurobiology, Dpt of Veterinary Medicine and Animal Sciences, Poznan University of Life Science, 60-625, Poznan, Poland
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Octreotide modulates the expression of somatostatin receptor subtypes in inflamed rat jejunum induced by Cryptosporidium parvum. PLoS One 2018. [PMID: 29522573 PMCID: PMC5844672 DOI: 10.1371/journal.pone.0194058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Somatostatins are proteins that are involved in gastrointestinal function. However, little is known with regard to somatostatin receptor subtype (SSTR) expression changes that occur in the jejunum during low-grade inflammation and during subsequent octreotide treatment. The aim of the present study was to investigate the expression of SSTRs in the jejunums of Cryptosporidium parvum (C. parvum)-infected rats by immunohistochemisty, reverse transcription (RT) PCR and quantitative real-time RT-PCR assays. Five-day-old suckling Sprague-Dawley rats (n = 15 for each group) were orally gavaged with 105 Nouzilly isolate (NoI) oocysts. Rats then received 50 μg/kg/day of octreotide by intraperitoneal injection from day 10 to day 17 post-infection. Animals were sacrificed on days 7 and 14 post-infection for immunohistochemical analysis and on days 14, 35 and 50 for mRNA expression analysis of SSTR subtypes. Histological analysis of jejunum tissues demonstrated infection of C. parvum along the villus brush border on day 7 post-infection and infection clearance by day 14 post-infection. Real-time PCR analysis indicated that in the inflamed jejunum, a significant increase in SSTR1 and SSTR2 expression was observed on day 14 post-infection. Octreotide therapy down-regulated the expression of SSTR2 on day 37 post-infection but significantly increased expression of SSTR1, SSTR2 and SSTR3 on day 50 post-infection. The results indicate that specific SSTRs may regulate the inflammatory pathway in the rat intestinal inflammation model.
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Gene expression profiling reveals a possible role for somatostatin in the innate immune response of the liver. GENOMICS DATA 2015; 5:42-45. [PMID: 26056631 PMCID: PMC4457384 DOI: 10.1016/j.gdata.2015.04.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Somatostatin is a neuropeptide hormone that inhibits pituitary growth hormone (GH) release. Using microarray analysis of gene expression in the livers of wildtype control and somatostatin knockout mice, we have previously identified a panel of genes whose GH-dependent and sexually dimorphic expression patterns are significantly altered by the absence of somatostatin (1). Here, we provide methodological and analytical details of that study, the raw data of which is deposited in the Gene Expression Omnibus as data set GSE56520. In addition, we performed further gene ontology analysis of the data and found that the differential expression of a second subset of genes in the livers of somatostatin-knockout mice versus wildtype controls is likely independent of GH signaling and involved in the innate immune response.
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Liu J, Peng L, Yang J, Wang M, Xu S, Liu J, Han P, He J, Tian D, Zhou Q. Sodium Ferulate Reduces Portal Pressure Through Inhibition of RhoA/Rho-Kinase and Activation of Endothelial Nitric Oxide Synthase in Cirrhotic Rats. Dig Dis Sci 2015; 60:2019-29. [PMID: 25724163 DOI: 10.1007/s10620-015-3544-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 01/16/2015] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND AIMS Recent studies have demonstrated that increased RhoA/Rho-kinase activity and reduced nitric oxide activity have the necessary machinery to induce cirrhosis. However, it is unclear whether this regulates the functions of hepatic stellate cells (HSCs). In this study, we used sodium ferulate (SF) in a cirrhotic rat model and examined its roles in regulating RhoA activation in HSCs and the subsequent effects on contraction of HSCs. METHODS Bile duct ligation method was used to induce cirrhosis in rats. Intrahepatic resistance was investigated in in situ perfused livers. Hepatic RhoA, Rho-kinase and eNOS expressions were studied by RT-PCR and Western blot. RhoA pull-down assay and collagen gel contraction assay of HSCs were performed by incubation with SF in the absence or presence of GGPP. RESULTS We showed that in cirrhotic liver, SF can efficiently affect RhoA activation via lowering the synthesis of GGPP in HSCs. These actions effectively reduced basal intrahepatic resistance in cirrhotic rats. Our study further suggested that SF effectively decreased Rho-kinase activity and increased activity of eNOS at both the mRNA and protein levels. SF treatment of HSCs reduced RhoA GTP without affecting the total RhoA protein level, and GGPP had the ability to block SF-induced protein expression. Furthermore, SF inhibited the contraction of activated HSCs and this inhibition was efficiently reversed by addition of GGPP. CONCLUSIONS SF inhibits hepatic RhoA/Rho-kinase signaling and activates the NO/PKG pathway in cirrhotic rats. This may serve as a mechanism for reducing the contraction of activated HSCs upon SF treatment.
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Affiliation(s)
- Jiqiao Liu
- Department of Medical Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, People's Republic of China,
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Hessheimer AJ, Escobar B, Muñoz J, Flores E, Gracia-Sancho J, Taurá P, Fuster J, Rimola A, García-Valdecasas JC, Fondevila C. Somatostatin therapy protects porcine livers in small-for-size liver transplantation. Am J Transplant 2014; 14:1806-16. [PMID: 24935350 DOI: 10.1111/ajt.12758] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/17/2014] [Accepted: 03/25/2014] [Indexed: 01/25/2023]
Abstract
Small-for-size (SFS) injury occurs in partial liver transplantation due to several factors, including excessive portal inflow and insufficient intragraft responses. We aim to determine the role somatostatin plays in reducing portal hyperperfusion and preventing the cascade of deleterious events produced in small grafts. A porcine model of 20% liver transplantation is performed. Perioperatively treated recipients receive somatostatin and untreated controls standard intravenous fluids. Recipients are followed for up to 5 days. In vitro studies are also performed to determine direct protective effects of somatostatin on hepatic stellate cells (HSC) and sinusoidal endothelial cells (SEC). At reperfusion, portal vein flow (PVF) per gram of tissue increased fourfold in untreated animals versus approximately threefold among treated recipients (p = 0.033). Postoperatively, markers of hepatocellular, SEC and HSC injury were improved among treated animals. Hepatic regeneration occurred in a slower but more orderly fashion among treated grafts; functional recovery was also significantly better. In vitro studies revealed that somatostatin directly reduces HSC activation, though no direct effect on SEC was found. In SFS transplantation, somatostatin reduces PVF and protects SEC in the critical postreperfusion period. Somatostatin also exerts a direct cytoprotective effect on HSC, independent of changes in PVF.
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Affiliation(s)
- A J Hessheimer
- Department of Surgery, Institut de Malalties Digestives I Metabòliques (IMDiM), Hospital Clínic, CIBERehd, IDIBAPS, University of Barcelona, Barcelona, Spain
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Klironomos S, Notas G, Sfakianaki O, Kiagiadaki F, Xidakis C, Kouroumalis E. Octreotide modulates the effects on fibrosis of TNF-α, TGF-β and PDGF in activated rat hepatic stellate cells. ACTA ACUST UNITED AC 2013; 188:5-12. [PMID: 24291170 DOI: 10.1016/j.regpep.2013.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 11/12/2013] [Accepted: 11/19/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Somatostatin and its analogs may influence hepatic fibrosis interfering through several mechanisms. The aim of this study was to investigate the effect of octreotide on cytokine activated hepatic stellate cells (HSC). METHODS Primary HSCs were isolated from rats and were cultured on plastic for activation. Expression of somatostatin receptors (SSTR) was investigated in cultured HSCs by immunofluorescence and western blot. The effect of octreotide on cellular proliferation was studied with the MTT assay and western blot for α1-procollagen (α1-PROC) production in TNFα, TGF-β1 or PDGF treated HSCs. Phosphotyrosine (PTP) and phosphoserine-phosphothreonine (STP) phosphatases inhibition was performed with sodium orthovanadate and okadaic acid respectively. RESULTS Activated HSC express SSTR subtypes 1, 2A, 2B, 3 and 4 and their expression is enhanced by further HSC activation. Octreotide did not have an effect on HSC proliferation but inhibited plastic induced α1-PROC production. Interestingly, it enhanced PDGF-induced HSC proliferation but inhibited PDGF and TGFβ1 dependent expression of α1-PROC, while an opposite effect was observed in TNFα-induced cell proliferation and collagen production. PTP inhibition reversed the inhibitory effect of octreotide on α1-PROC, but potentiated its effect on PDGF and TGFβ1 dependent α1-PROC production. Finally, STP inhibition profoundly inhibited α1-PROC expression in all cases suggesting that both STP and PTP phosphatases are important regulators of pro-fibrotic mechanisms. CONCLUSIONS The net effect of octreotide on HSCs and therefore liver fibrosis is subject to the cytokine microenvironment of these cells. This effect is modulated by PTPs and STPs inhibition. Especially in the case of STPs their profibrotic effects could be an interesting new therapeutic target in liver fibrosis.
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Affiliation(s)
- Stefanos Klironomos
- Liver Research Laboratory, Medical School, University of Crete, Voutes 71003 Crete, Greece
| | - George Notas
- Liver Research Laboratory, Medical School, University of Crete, Voutes 71003 Crete, Greece; Laboratory of Experimental Endocrinology, Medical School, University of Crete, Voutes 71003 Crete, Greece
| | - Ourania Sfakianaki
- Liver Research Laboratory, Medical School, University of Crete, Voutes 71003 Crete, Greece
| | - Foteini Kiagiadaki
- Laboratory of Experimental Endocrinology, Medical School, University of Crete, Voutes 71003 Crete, Greece
| | - Costas Xidakis
- Liver Research Laboratory, Medical School, University of Crete, Voutes 71003 Crete, Greece
| | - Elias Kouroumalis
- Liver Research Laboratory, Medical School, University of Crete, Voutes 71003 Crete, Greece.
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Role of resident liver cells in the pathogenesis of schistosomiasis. Trends Parasitol 2012; 28:572-9. [PMID: 23099112 DOI: 10.1016/j.pt.2012.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 09/14/2012] [Accepted: 09/21/2012] [Indexed: 12/12/2022]
Abstract
Pathology in schistosomiasis occurs as a result of eggs deposited in the liver by the schistosome parasite. A granulomatous reaction occurs, resulting in portal hypertension and hepatic fibrosis. Resident non-parenchymal cells within the liver take part in this process, including hepatic stellate cells, which are responsible for collagen production, and Kupffer cells, the liver macrophages involved in both host protection and in pathology. Other cells such as liver sinusoidal endothelial cells or portal fibroblasts may also be involved in this process. This review discusses the possible role of these resident liver cells in the pathology associated with schistosomiasis and provides information which may assist our understanding of the mechanisms associated with chronic liver disease in general.
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Yang YY, Tsai TH, Huang YT, Lee TY, Chan CC, Lee KC, Lin HC. Hepatic endothelin-1 and endocannabinoids-dependent effects of hyperleptinemia in nonalcoholic steatohepatitis-cirrhotic rats. Hepatology 2012; 55:1540-50. [PMID: 22183953 DOI: 10.1002/hep.25534] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 11/22/2012] [Indexed: 12/15/2022]
Abstract
UNLABELLED Leptin, the ob gene product, is a protein released from adipocytes and has been detected in fibrotic and cirrhotic livers. Leptin in brain has an inhibitory effect on food intake. Nonalcoholic steatohepatitis (NASH) is characterized by hyperleptinemia. This study explores the possible mechanisms of hyperleptinemia in relation to increased intrahepatic resistance (IHR) and portal hypertension in NASH cirrhotic rats. NASH cirrhotic rats with hyperleptinemia were induced in Zucker (fa/fa) and lean rats by feeding the animals a high fat/methionine-choline-deficient (HF/MCD) diet with and without exogenous administration of recombinant leptin. Portal venous pressure (PVP), IHR, plasma and hepatic levels of various substances, histopathology of the liver, the hepatic hydroxyproline content, and the expression of various hepatic protein and messenger RNA (mRNA) were measured. Hepatic microcirculatory dysfunction and the vasoconstrictive response to endothelin-1 were also observed using a liver perfusion system and intravital microscopy. Finally, the effect of leptin on hepatic stellate cells (HSCs) was evaluated. Both in HF/MCD-Zucker and HF/MCD+leptin lean rats, significant hepatic fibrogenesis and cirrhosis, marked portal hypertension, microcirculatory dysfunction, an enhanced vasoconstrictive response to endothelin-1, and an increased IHR were found to be associated with higher levels of hepatic endothelin-1 and endocannabinoids, expression levels of the cannabinoid type 1 receptor, endothelin-1 type A receptor (ET(A) R), activator protein-1, transforming growth factor beta (TGF-β)(1), osteopontin, tumor necrosis factor alpha (TNF-α), leptin, and the leptin receptor (OBRb). Interestingly, acute incubation of leptin directly increases the expression of ET(A) R, OBRb and activator protein-1 in HSCs. CONCLUSION An HF/MCD diet and hyperleptinemia increase hepatic endocannabinoids production, promote hepatic fibrogenesis, enhance the hepatic vasoconstrictive response to endothelin-1, and aggravate hepatic microcirculatory dysfunction; these events subsequently increase IHR and portal hypertension in NASH cirrhotic rats.
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Affiliation(s)
- Ying-Ying Yang
- Division of General Medicine, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
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Seo YS, Shah VH. Pathophysiology of portal hypertension and its clinical links. J Clin Exp Hepatol 2011; 1:87-93. [PMID: 25755320 PMCID: PMC3940250 DOI: 10.1016/s0973-6883(11)60127-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 07/27/2011] [Indexed: 02/08/2023] Open
Abstract
Portal hypertension is a major cause of morbidity and mortality in patients with liver cirrhosis. Intrahepatic vascular resistance due to architectural distortion and intrahepatic vasoconstriction, increased portal blood flow due to splanchnic vasodilatation, and development of collateral circulation have been considered as major factors for the development of portal hypertension. Recently, sinusoidal remodeling and angiogenesis have been focused as potential etiologic factors and various researchers have tried to improve portal hypertension by modulating these new targets. This article reviews potential new treatments in the context of portal hypertension pathophysiology concepts.
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Key Words
- AT, angiotensin
- ET-1, endothelin-1
- HSC, hepatic stellate cell
- HVPG, hepatic venous pressure gradient
- NO, nitric oxide
- PDGF, platelet-derived growth factor
- PIGF, placenta! growth factor
- RAS, renin-angiotensin system
- RCT, randomized controlled trial
- VEGF, vascular endothelial growth factor
- angiogenesis
- eNOS, endothelial nitric oxide synthase
- pathophysiology
- portal hypertension
- sinusoids
- treatment
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Affiliation(s)
- Yeon Seok Seo
- Gastroenterology Research Unit, Mayo Clinic, Rochester, MN - 55905, USA
| | - Vijay H Shah
- Gastroenterology Research Unit, Mayo Clinic, Rochester, MN - 55905, USA,Mayo Clinic Center for Cell Signaling in Gastroenterology, Mayo Clinic, Rochester, MN - 55905, USA,Address for correspondence: Dr Vijay H Shah, Gastroenterology Research Unit, Mayo Clinic, 200 First Street SW, Rochester, MN - 55905, USA
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16
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Maruyama T, Ayabe S, Murata T, Hori M, Ozaki H. Relaxant effect of prostaglandin D(2)--receptor DP agonist on liver myofibroblast contraction. J Pharmacol Sci 2011; 116:197-203. [PMID: 21613754 DOI: 10.1254/jphs.10325fp] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Increased intrahepatic resistance causes portal hypertension in cirrhosis. Liver myofibroblasts (MFs) are now regarded as the principle cells involved in sinusoidal blood flow regulation. Many other prostaglandin-receptor agonists have been reported to regulate liver MF contraction, but the role of the prostaglandin D(2)-receptor DP is unknown. In this study, we investigated the effect of a synthetic agonist of prostanoid DP receptor, BW245C, on contractile properties of primary rat liver MFs. Collagen gel contraction assay revealed that BW245C alone (1 and 10 µM) did not induce contraction but induced cell relaxation. Pretreatment with BW245C (10 µM, 30 min) attenuated bradykinin (100 nM)-induced liver MF contraction. Elevation of [Ca(2+)](i) induced by bradykinin (100 nM) was partially suppressed by BW245C pretreatment (10 µM, 3 min). BW245C (1 and 10 µM) significantly increased intracellular cAMP level in a dose-dependent manner. Pretreatment with forskolin (30 - 300 nM, 30 min) and dibutyryl-cAMP (3 - 30 µM, 30 min) significantly reduced bradykinin-induced contraction. Furthermore, a protein kinase A (PKA) inhibitor KT5720 (10 nM to 1 µM, 30 min) blocked the relaxant effect of BW245C. These results suggest that prostanoid DP receptor agonism inhibits bradykinin-induced [Ca(2+)](i) elevation and contraction through cAMP-PKA signal activation in rat liver MFs.
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Affiliation(s)
- Tomoharu Maruyama
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Japan
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17
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Borbath I, Leclercq IA, Sempoux C, Abarca-Quinones J, Desaeger C, Horsmans Y. Efficacy of lanreotide in preventing the occurrence of chemically induced hepatocellular carcinoma in rats. Chem Biol Interact 2010; 183:238-48. [DOI: 10.1016/j.cbi.2009.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 10/01/2009] [Accepted: 10/16/2009] [Indexed: 12/26/2022]
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Liu Z, van Grunsven LA, Van Rossen E, Schroyen B, Timmermans JP, Geerts A, Reynaert H. Blebbistatin inhibits contraction and accelerates migration in mouse hepatic stellate cells. Br J Pharmacol 2009; 159:304-15. [PMID: 20039876 DOI: 10.1111/j.1476-5381.2009.00477.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Blebbistatin, an inhibitor of myosin-II-specific ATPase, has been used to inhibit contraction of invertebrate and mammalian muscle preparations containing non-muscle myosin. Activated hepatic stellate cells have contractile properties and play an important role in the pathophysiology of liver fibrosis and portal hypertension. Therefore, hepatic stellate cells are considered as therapeutic target cells. In the present study, we studied the effect of blebbistatin during the transition of mouse hepatic stellate cells into contractile myofibroblasts. EXPERIMENTAL APPROACH Effects of blebbistatin on cell morphology were evaluated by phase contrast microscopy. Cell stress fibres and focal adhesions were investigated by dual immunofluorescence staining and visualized using fluorescence microscopy. Contractile force generation was examined by silicone wrinkle formation assays and collagen gel contraction assays. Intracellular Ca(2+) release in response to endothelin-1 was measured by using Fluo-4. Cell migration was measured by wound healing experiments. KEY RESULTS In culture-activated hepatic stellate cells, blebbistatin was found to change both cell morphology and function. In the presence of blebbistatin, stellate cells became smaller, acquired a dendritic morphology and had less myosin IIA-containing stress fibres and vinculin-containing focal adhesions. Moreover, blebbistatin impaired silicone wrinkle formation, reduced collagen gel contraction and blocked endothelin-1-induced intracellular Ca(2+) release. Finally, it promoted wound-induced cell migration. CONCLUSIONS AND IMPLICATIONS By inhibiting myosin II ATPase, blebbistatin has profound effects on the morphology and function of activated hepatic stellate cells. Our data suggest that myosin II could be a therapeutic target in the treatment of liver fibrosis and portal hypertension.
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Affiliation(s)
- Zhenan Liu
- Department of Cell Biology, Vrije Universiteit Brussel, Brussels, Belgium
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Ye H, He B, Wang J. Effects of somatostatin on portal vein hemodynamics in the early stage after hepatectomy. Shijie Huaren Xiaohua Zazhi 2009; 17:2026-2030. [DOI: 10.11569/wcjd.v17.i20.2026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effects of somatostatin on portal vein hemodynamics in the early stage after hepatectomy and explore the mechanism under such effects.
METHODS: Thirty-two rabbits were randomly divided into three groups: group A (n = 6, control group), group B (n = 13, normal saline treatment group) and group C (n = 13, somatostatin treatment group). Rabbits in all three groups underwent portal vein catheterization, while only those in Groups B and C underwent 50% partial hepatectomy. An intraoperative and postoperative intravenous infusion of normal saline and somatostatin was given. Before and after the treatment (0.5, 1, 2 h), the pressure, flow direction, diameter, hemokinetic velocity, average flow rate and blood flow of the portal vein were detected and compared.
RESULTS: After hepatectomy, the portal pressure increased. The increase in the portal pressure in group B was significantly higher than that in group C (0.5 h: 436.001 ± 169.654 Pa vs 258.012 ± 167.497 Pa, P < 0.05; 1 h: 394.324 ± 163.182 Pa vs 224.767 ± 164.653 Pa, P < 0.05; 2 h: 193.092 ± 154.356 Pa vs 351.861 ± 183.579 Pa, P < 0.05). There were no significant differences in portal diameter and hemokinetic velocity among all the three groups before and after treatment (P > 0.05). However, the average flow rate and blood flow of the portal vein in group C were significant lower than those in groups A and B (both P < 0.05). Two hours after hepatectomy, no significant differences in the expression of ALT and AST were noted between groups A and B.
CONCLUSION: Application of somatostatin in the early stage of hepatectomy may reduce elevated portal pressure, which may be associated with somatostatin-induced decrease in flow rate and blood flow of the portal vein.
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20
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Ayabe S, Murata T, Maruyama T, Hori M, Ozaki H. Prostaglandin E2 induces contraction of liver myofibroblasts by activating EP3 and FP prostanoid receptors. Br J Pharmacol 2009; 156:835-45. [PMID: 19239477 DOI: 10.1111/j.1476-5381.2008.00051.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE Increased portal pressure in liver injury results from hypercontraction of perivascular non-parenchymal cells including liver myofibroblasts (MFs). Prostaglandin E2 (PGE2) is the major eicosanoid which is released around the venous system during liver injury, but little is known about their contractile effect on MFs. EXPERIMENTAL APPROACH Contraction of primary rat liver MFs was measured by a collagen gel contraction assay. Expression of E prostanoid (EP) receptor subtypes was assessed by reverse transcription-polymerase chain reaction. Fura-2 fluorescence was used to determine intracellular Ca2+ concentration ([Ca2+](i)). Phosphorylation of protein kinase C (PKC) was detected by Western blot analysis. KEY RESULTS Liver MFs expressed mRNAs for all four EP receptors. PGE2 induced contraction in a dose- and time-dependent manner, and slightly increased [Ca2+](i) only at high concentrations (10 micromol.L(-1)). An agonist selective for EP(3) receptors, ONO-AE-248, dose-dependently induced MF contraction but did not increase [Ca2+](i). Pretreatment with rottlerin (a specific novel PKC inhibitor) and Ro 31-8425 (a general PKC inhibitor) significantly reduced 1 micromol.L(-1) PGE(2)- or ONO-AE-248-induced contractions. Furthermore, 1 micromol.L(-1) PGE(2) stimulated phosphorylation of PKC isoforms PKCdelta and PKCepsilon. The F prostanoid (FP) receptor antagonist AL8810 abolished the [Ca(2+)](i) elevation and the rapid contraction induced by 10 micromol.L(-1) PGE2. CONCLUSIONS AND IMPLICATIONS Lower concentrations up to 1 micromol.L(-1) of PGE2 induce liver MF contraction via a [Ca2+](i)-independent PKC-mediated pathway through the EP(3) receptor, while higher concentrations have an additional pathway leading to Ca(2+)-dependent contraction through activating the FP receptor.
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Affiliation(s)
- S Ayabe
- Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
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21
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Soon RK, Yee HF. Stellate cell contraction: role, regulation, and potential therapeutic target. Clin Liver Dis 2008; 12:791-803, viii. [PMID: 18984467 PMCID: PMC2600510 DOI: 10.1016/j.cld.2008.07.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The contraction of hepatic stellate cells has been proposed to mediate fibrosis by regulating sinusoidal blood flow and extracellular matrix remodeling. Abundant data from diverse, yet complementary, experimental methods support a robust model for the regulation of contractile force generation by stellate cells. In this model, soluble factors associated with liver injury, including endothelin 1 and nitric oxide, are transduced primarily through Rho signaling pathways that promote the myosin II-powered generation of contractile force by stellate cells. The enhanced knowledge of the role and differential regulation of stellate cell contraction may facilitate the discovery of new and targeted strategies for the prevention and treatment of hepatic fibrosis.
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Affiliation(s)
- Russell K. Soon
- Research Associate, Department of Medicine and Liver Center, University of California, San Francisco, San Francisco, California
| | - Hal F. Yee
- William and Mary Ann Rice Memorial Distinguished Professor, Department of Medicine and Liver Center, University of California San Francisco; Chief of Gastroenterology and Hepatology, San Francisco General Hospital; San Francisco, California
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Yang WY, Wu JX, Dai Q, Jiang FH. Effect of long-acting octreotide on portal hypertension in rats with liver fibrosis. Shijie Huaren Xiaohua Zazhi 2008; 16:2815-2819. [DOI: 10.11569/wcjd.v16.i25.2815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To observe the effect of long-acting release octreotide (Sandostatin LAR) on the genesis of portal hypertension in rats with liver fibrosis induced by carbon tetrachloride (CCl4).
METHODS: Forty SD rats were assigned randomly into 3 groups: normal control group (n = 8), fibrosis with portal hypertension group (n = 16) and Sandostatin LAR group (n = 16). Except those in the normal control group, the rats in the remaining two groups were subcutaneously injected with 400 mL/L CCl4 (3 mL/kg) for induction of fibrosis with portal hypertension. Sandostatin LAR (0.8 mg/kg) was used intramuscularly once every 4 weeks. After 8 weeks, the pressures of portal vein were measured before pathological evaluation including macroscopic features of the liver, and plasma glucagon as well as endothelin was determined by radioimmunoassay.
RESULTS: The portal pressure, plasma glucagon and endothelin levels were significantly lower in the Sandostatin LAR group than those in the fibrosis with portal hypertension group (t = 2.5, P < 0.05; t = 2.088, P < 0.05; t = 2.102, P < 0.05), but still higher than those in the normal control group (t = 5.152, P < 0.01; t = 2.896, P < 0.01; t = 2.770, P < 0.05). In the normal control group, liver morphology and histology were had no abnormal changes; in the fibrosis with portal hypertension group and Sandostatin LAR group, fibrotic changes were observed, and moreover, the severity was higher in the former group (P < 0.05).
CONCLUSION: Long-acting octreotide can remarkably decrease the pressures of portal vein, which may be attributed to reduced liver fibrosis and decreased plasma glucagon and endothelin levels.
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23
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Somatostatin inhibits colon cancer cell growth through cyclooxygenase-2 downregulation. Br J Pharmacol 2008; 155:198-209. [PMID: 18587421 DOI: 10.1038/bjp.2008.268] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE Cyclooxygenase-2 (COX-2) is expressed in colonic neoplasms, where it supports cell proliferation via prostaglandin E(2) (PGE(2)) production. This study investigated the effects of somatostatin-14 on COX-2 expression, PGE(2) production and proliferation in colon cancer cells. EXPERIMENTAL APPROACH Human colon adenocarcinoma cell lines Caco-2, HT-29 and HCT116 were used. The following techniques were employed: colourimetric assay for cell growth; 5-bromo-2'-deoxyuridine assay for DNA synthesis; enzyme immunoassay for PGE(2); COX-2 mRNA silencing; RT-PCR or Western blot for somatostatin receptor subtypes, cyclooxygenase isoforms, phosphorylated-ERK-1/ERK-2 and phosphorylated-Akt. KEY RESULTS HT-29 and Caco-2 cells expressed COX-2 and somatostatin receptors (sst(3/4/5) and sst(3/5), respectively). HCT116 cells did express somatostatin receptors (sst(2/3/5)), but not COX-2. Somatostatin-14 inhibited basal COX-2 expression, PGE(2) production, DNA synthesis and growth in Caco-2 cells and these effects were prevented by BN81658 (sst(3) receptor antagonist). Basal proliferation of HT-29, HCT116 and COX-2-silenced Caco-2 cells was not affected by somatostatin-14. Stimulation of HT-29 cells with gastrin-17 elicited increments of ERK-1/ERK-2 and Akt phosphorylation, COX-2 expression, PGE(2) production, DNA synthesis and cell growth, which were all counteracted by somatostatin-14. Somatostatin-14-induced inhibition of COX-2 expression, PGE(2) production and DNA synthesis were blocked by BIM23056 (sst(5) receptor antagonist). CONCLUSIONS AND IMPLICATIONS Somatostatin decreases COX-2 expression and function in colon cancer cells via activation of sst(3) or sst(5) receptors, and these effects contribute to the inhibitory action of somatostatin on cell proliferation. These findings can be relevant to the development of therapeutic strategies based on the modulation of the COX-2 pathway.
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Reynaert H, Urbain D, Geerts A. Regulation of sinusoidal perfusion in portal hypertension. Anat Rec (Hoboken) 2008; 291:693-8. [PMID: 18484616 DOI: 10.1002/ar.20669] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Portal hypertension, a major complication of cirrhosis, is caused by both increased portal blood flow and augmented intrahepatic vascular resistance. Even though the latter is primarily caused by anatomical changes, it has become clear that dynamic factors contribute to the increased hepatic vascular resistance. The hepatic sinusoid is the narrowest vascular structure within the liver and is the principal site of blood flow regulation. The anatomical location of hepatic stellate cells, which embrace the sinusoids, provides a favorable arrangement for sinusoidal constriction, and for control of sinusoidal vascular tone and blood flow. Hepatic stellate cells possess the essential contractile apparatus for cell contraction and relaxation. Moreover, the mechanisms of stellate cell contraction are better understood, and many substances which influence contractility have been identified, providing a rationale and opportunity for targeting these cells in the treatment of portal hypertension in cirrhosis.
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Affiliation(s)
- Hendrik Reynaert
- Department of Cell Biology, Vrije Universiteit Brussel, Brussel, Brussels, Belgium.
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25
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Vanheule E, Geerts AM, Reynaert H, Van Vlierberghe H, Geerts A, De Vos M, Colle I. Influence of somatostatin and octreotide on liver microcirculation in an experimental mouse model of cirrhosis studied by intravital fluorescence microscopy. Liver Int 2008; 28:107-16. [PMID: 18173562 DOI: 10.1111/j.1478-3231.2007.01629.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND AIMS Chronic liver damage causes hepatic stellate cell (HSC) activation and contraction, leading to intrahepatic microvascular and structural changes. In vitro endothelin-1 (ET-1)-induced contraction of HSCs can be reduced by somatostatin (SST); however, intrahepatic in vivo effects have never been studied. METHODS Sinusoidal diameter was measured by intravital fluorescence microscopy in carbon tetrachloride (CCl(4)) and control mice before and after an intravenous (IV) bolus and after 0, 5, 10 and 15 min of an IV infusion of saline, 8 microg/kg/h SST or 8 microg/kg/h octreotide. RESULTS The baseline sinusoidal diameter in CCl(4) mice (3.01+/-0.05 microm) was significantly smaller than that in controls (4.37+/-0.06 microm). The sinusoidal diameter increased significantly in both groups after a bolus (27, 16% respectively) and following 5 min of SST IV infusion (28, 14% respectively). The percentage increase was significantly higher in CCl(4) mice as compared with controls. This dilatory effect continued for at least 15 min. SST did not influence the mean arterial blood pressure (MAP) and portal venous inflow. In none of the groups did octreotide or saline have any influence on sinusoidal diameters, MAP and portal venous inflow. CONCLUSIONS Sinusoidal diameter in cirrhotic mice is significantly smaller than that in controls. SST causes significant sinusoidal dilation following a bolus and for at least 15 min of IV infusion. Octreotide does not have any influence on liver sinusoids. These results demonstrate for the first time the in vivo dilatory effect of SST on liver sinusoids.
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Affiliation(s)
- Eline Vanheule
- Department of Hepatology and Gastroenterology, Ghent University Hospital, Ghent, Belgium.
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Borbath I, Leclercq IA, Abarca-Quinones J, Desaeger C, Lebrun V, Moulin P, Sempoux C, Horsmans Y. Inhibition of early preneoplastic events in the rat liver by the somatostatin analog lanreotide. Cancer Sci 2007; 98:1831-9. [PMID: 17900309 PMCID: PMC11158449 DOI: 10.1111/j.1349-7006.2007.00626.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 08/16/2007] [Accepted: 08/21/2007] [Indexed: 12/21/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death, and its incidence is increasing worldwide. Due to the known risk factors (mainly hepatitis B and C viruses), we believe there is a rationale for a chemopreventive approach to treat HCC. Here, based on described in vitro data, we evaluated the preventive effects of lanreotide, a somatostatin analog, on the induction of early carcinogenic events. We monitored preneoplastic foci induced by a two-stage initiation/promotion model of hepatocarcinogenesis in male Wistar rats, using diethylnitrosamine and 2-acetylaminofluorene. Lanreotide was given starting the day after the first diethylnitrosamine injection. By quantitative morphometry, we showed that lanreotide significantly decreases the size of induced preneoplastic foci. Analysis of proliferation and apoptosis assessed by immunohistochemistry, showed decreased proliferation and increased cell death in rats treated with lanreotide. As these events were associated with a significant decreased expression of the cell cycle regulator cyclin D1 and an increased expression of the cyclin-dependent kinase inhibitor p27(kip1) compared to the non-treated group, it is tempting to speculate that these factors are involved in the favorable effect of lanreotide. In conclusion, lanreotide significantly decreases early carcinogenic transformation in a two-step rat model. As lanreotide has a low toxicity profile, we believe it would be interesting to evaluate its effect in chemoprevention of HCC.
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Affiliation(s)
- Ivan Borbath
- Gastroenterology Laboratory, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Avenue Hippocrate, 10, Brussels 1200, Belgium.
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27
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Vlachogiannakos J, Kougioumtzian A, Triantos C, Viazis N, Sgouros S, Manolakopoulos S, Saveriadis A, Markoglou C, Economopoulos T, Karamanolis DG. Clinical trial: The effect of somatostatin vs. octreotide in preventing post-endoscopic increase in hepatic venous pressure gradient in cirrhotics with bleeding varices. Aliment Pharmacol Ther 2007; 26:1479-87. [PMID: 17919272 DOI: 10.1111/j.1365-2036.2007.03539.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Hepatic venous pressure gradient (HVPG) increases significantly after endoscopic therapy in patients with bleeding oesophageal varices, which may precipitate further haemorrhage. Whether vasoactive drugs can suppress these changes remains unknown. AIM To investigate the efficacy of somatostatin when compared with octreotide in preventing the post-endoscopic increase in HVPG during acute bleeding and whether the changes affect outcome. METHODS Thirty-three cirrhotics with bleeding varices were randomized to receive somatostatin (n = 17) or octreotide (n = 16) under double-blind conditions, soon after their admission. HVPG measurements were performed before and immediately after endoscopic treatment. RESULTS In the somatostatin group, postendotherapy HVPG values did not change significantly when compared with pre-treatment values (18.9 vs. 17.2, P = 0.092). Conversely, in the octreotide group, HVPG increased significantly after endoscopy (18.2 vs. 20.8, P = 0.003). The probability of 6-week survival without treatment failure was significantly higher in the somatostatin group (P = 0.024). Post-endoscopic HVPG value was independently associated with 6-week failure. CONCLUSIONS Somatostatin, but not octreotide, effectively prevents the post-endoscopic increase in HVPG, which may be associated with low probability of treatment failure.
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Affiliation(s)
- J Vlachogiannakos
- 2nd Department of Gastroenterology, Evangelismos Hospital, Athens, Greece.
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28
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Reynaert H, van Rossen E, Uyama N, Chatterjee N, Kumar U, Urbain D, Geerts A. Expression of somatostatin receptors in splanchnic blood vessels of normal and cirrhotic rats. Liver Int 2007; 27:825-31. [PMID: 17617126 DOI: 10.1111/j.1478-3231.2007.01503.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND/AIMS Somatostatin has been used for over two decades to treat acute variceal bleeding. Although it is assumed that somatostatin lowers portal pressure by constriction of the splanchnic arteries, little is known about the expression of somatostatin receptors (SSTR) in splanchnic blood vessels. In this study we investigated SSTR expression in splanchnic blood vessels from normal and cirrhotic rats. METHODS/RESULTS Cirrhosis was induced by intraperitoneal injection of 50 mg thioacetamide twice a week for 14 weeks. In portal vein, mesenteric artery and aorta of normal and cirrhotic rats, mRNA for the five known SSTR was measured by quantitative reverse transcriptase-polymerase chain reaction. SSTR subtypes 1, 2, 3 and 4 were expressed, but subtype 5 was undetectable. In the portal vein of cirrhotic animals, SSTR1 was significantly down-regulated as compared with controls. Otherwise, no major differences in receptor expression between normal and cirrhotic animals were observed. Using immunohistochemistry, we identified all five receptors, although the staining of receptor 5 was very weak. CONCLUSION All five SSTR are expressed in splanchnic blood vessels. Our results suggest that cirrhosis reduces expression of SSTR1 in portal vein. In other vessels, no major differences between the normal and cirrhotic state were noted.
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Affiliation(s)
- Hendrik Reynaert
- Department of Cell Biology, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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Jung Y, Oh SH, Zheng D, Shupe TD, Witek RP, Petersen BE. A potential role of somatostatin and its receptor SSTR4 in the migration of hepatic oval cells. J Transl Med 2006; 86:477-89. [PMID: 16534498 DOI: 10.1038/labinvest.3700410] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Somatostatin (SST) is a regulatory peptide that activates G protein-coupled receptors comprised of five members (somatostatin receptors (SSTRs) 1-5). Despite the broad use of SST and its analogs in clinical practice, the spectrum of SST activities has been incompletely defined. Recently, it has been demonstrated that SST can be a chemoattractant for hematopoietic precursor cells. Since hepatic oval cells (HOCs) share common characteristics with hematopoietic stem cells, we hypothesized that SST could act as a chemoattractant for HOCs by stimulating SSTRs. Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot assay revealed an increased expression of SST in the 2-acetyl-aminofluorene (2AAF)/partial hepatectomy (PHx) HOC induction model. Immunohistochemical staining showed the expression of SST in 2AAF/PHx-treated rat liver, as compared to normal liver. Proliferation and migration assays demonstrated that the increase of SST was related to migration of HOCs, but not their proliferation. RT-PCR and quantitative real-time PCR showed that SSTR4 was preferentially expressed by HOCs. Western blot assay and immunohistochemical staining confirmed the expression of SSTR4 by HOCs. In addition, pretreatment with anti-SSTR4 antibody cultures resulted in a dramatic reduction of cell migration as compared to that of control. Lastly, SST stimulated the rearrangement of actin filaments in HOCs, while HOCs treated with anti-SSTR4 antibody failed to do so. These results suggest a positive role for SST in the migration of HOCs, and that this effect is mediated through SSTR4.
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Affiliation(s)
- Youngmi Jung
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610-0275, USA
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Xu X, Man K, Zheng SS, Liang TB, Lee TK, Ng KT, Fan ST, Lo CM. Attenuation of acute phase shear stress by somatostatin improves small-for-size liver graft survival. Liver Transpl 2006; 12:621-7. [PMID: 16555322 DOI: 10.1002/lt.20630] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The major concern of living donor liver transplantation is small-for-size graft injury at the early phase after transplantation. Novel therapeutic strategies should be developed. To investigate the protective effect of somatostatin related to hemodynamic stress on small-for-size liver graft injury, we applied a treatment regimen of low-dose somatostatin in a rat orthotopic liver transplantation model using small-for-size grafts (median, 38.7%; range, 35-42%). Somatostatin was given at 5 minutes before total hepatectomy and immediately after reperfusion in the recipient (20 microg/kg). Graft survival, portal hemodynamics, intragraft gene expression and hepatic ultrastructural changes were compared between the rats with or without somatostatin treatment. Seven-day graft survival rates in the somatostatin treatment group were significantly improved compared to the control group (66.7% vs. 16.7%, P = 0.036). In the treatment group, portal pressure and hepatic surface blood flow were significantly decreased within the first 30 minutes after reperfusion, whereas in the control group, transient portal hypertension and excessive hepatic blood flow were observed. Intragraft expression (both messenger RNA and protein) of endothelin-1 was significantly downregulated accompanied with upregulation of heme oxygenase-1 and A20. Better preservation of liver function was found in the treatment group. Hepatic ultrastructure, especially the integrity of sinusoids, was well protected in the treatment group. In conclusion, low-dose somatostatin rescues small-for-size grafts from acute phase injury in liver transplantation by attenuation of acute-phase shear stress that resulted from transient portal hypertension.
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Affiliation(s)
- Xiao Xu
- Centre for the Study of Liver Disease and Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong, China
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Reynaert H, Rombouts K, Jia Y, Urbain D, Chatterjee N, Uyama N, Geerts A. Somatostatin at nanomolar concentration reduces collagen I and III synthesis by, but not proliferation of activated rat hepatic stellate cells. Br J Pharmacol 2005; 146:77-88. [PMID: 15980876 PMCID: PMC1576247 DOI: 10.1038/sj.bjp.0706298] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Previous studies have shown antifibrotic effects of somatostatin. Since hepatic stellate cells (HSC) express somatostatin receptors and play a key role in hepatic fibrogenesis, we investigated the in vitro antifibrotic effect of somatostatin on rat HSC. At day 12 after isolation, cells were exposed to different concentrations of somatostatin (10(-6)-10(-9) mol l(-1)). mRNA expression of collagen types I and III, and of smooth muscle alpha-actin (alpha-SMA) was analysed by Northern blotting. At 10(-9) mol l(-1), somatostatin significantly reduced mRNA expression of collagen I (72.3 +/- 10.7%; 95% confidence interval (95% CI): 45.5-99.0), collagen III (79.0 +/- 4.5%; 95% CI: 67.6-90.4) and alpha-SMA (65.7 +/- 5.9%; 95% CI: 51.1-80.2), as compared to control normalized at 100%. These results were confirmed by quantitative RT-PCR. Cycloheximide experiments indicated that somatostatin has no direct transcriptional effect.Using immunoprecipitation, we demonstrated that somatostatin also decreased de novo synthesis of collagen I (73 +/-10%; 95% CI: 48-98%), collagen III (65 +/- 13%; 95% CI: 33-97%) and alpha-SMA (47 +/- 9%; 95% CI: 25-69%). Remarkably, at higher concentrations, somatostatin did not suppress collagen mRNA expression nor de novo protein synthesis. We ascribe this observation to desensitization of the cells for somatostatin. Cell proliferation, as measured by 5-bromo-2'-deoxyuridine labelling, was not altered by somatostatin. No significant effect on the intermediate and actin cytoskeleton were detected by immunohistochemistry and Western blotting. Our findings imply that in vivo antifibrotic effects of somatostatin could result partially from a direct action of somatostatin on HSC, but other, in vivo effects are probably also involved.
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Affiliation(s)
- Hendrik Reynaert
- Laboratory for Liver Cell Biology, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
- Division of Gastroenterology-Hepatology, University Hospital Vrije Universiteit Brussel (AZ-VUB), Laarbeeklaan 101, 1090 Brussels, Belgium
- Author for correspondence:
| | - Krista Rombouts
- Laboratory for Liver Cell Biology, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Yutao Jia
- Laboratory for Liver Cell Biology, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Daniel Urbain
- Division of Gastroenterology-Hepatology, University Hospital Vrije Universiteit Brussel (AZ-VUB), Laarbeeklaan 101, 1090 Brussels, Belgium
| | - Nirjhar Chatterjee
- Centre of Excellence, UCB, Allée de la Recherche 60, 1070 Brussels, Belgium
| | - Naoki Uyama
- Laboratory for Liver Cell Biology, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Albert Geerts
- Laboratory for Liver Cell Biology, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
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Abstract
Portal hypertension (PHT) is responsible for the more severe and often lethal complications of cirrhosis such as bleeding oesophageal varices, ascites, renal dysfunction and hepatic encephalopathy. Because of the combined impact of these complications, PHT remains the most important cause of morbidity and mortality in patients with cirrhosis. Over the years, it has become clear that a decrease in portal pressure is not only protective against the risk of variceal (re)bleeding but is also associated with a lower long-term risk of developing complications and an improved long-term survival. A milestone in therapy was the introduction of non-selective beta-blockers for the prevention of bleeding and rebleeding of gastro-esophageal varices. However, in practice, less than half the patients under beta-blockade are protected from these risks, supporting the overall demand for innovation and expansion of our therapeutic armamentarium. Recent advances in the knowledge of the pathophysiology of cirrhotic PHT have directed future therapy towards the increased intrahepatic vascular resistance, which, in part, is determined by an increased hepatic vascular tone. This increased vasculogenic component provides the rationale for the potential use of therapies aimed at increasing intrahepatic vasorelaxing capacity via gene therapy, liver-selective nitric oxide donors and statines on the one hand, and at antagonizing excessive intrahepatic vasoconstrictor force through the use of endothelin antagonists, angiotensin blockers, alpha(1) adrenergic antagonists or combined alpha(1)- and non-selective beta-blockers or somatostatin analogues on the other. The focus of this review is to give an update on the pathophysiology of PHT in order to elucidate these potential novel strategies subsequently.
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Affiliation(s)
- Wim Laleman
- Department of Hepatology, University Hospital Gasthuisberg, Leuven, Belgium
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Xue XL, Lin JS, Sun XM, Zhou HJ. Effect of octreotide on regulation of intracellular free Ca 2+ concentration of hepatic stellate cells in rats. Shijie Huaren Xiaohua Zazhi 2005; 13:1974-1977. [DOI: 10.11569/wcjd.v13.i16.1974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of octreotide on the regulation of intracellular free Ca2+ concentration ([Ca2+]i) and proliferation of hepatic stellate cells (HSCs) in rats.
METHODS: Fluorescence Ca2+ indicator Fura-2/AM was used to observe the [Ca2+]i of HSCs in normoxic and chronic hypoxic condition. The effects of octreotide on the proliferation of HSCs were assessed by MTT assay, and the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were detected by radioimmunoassay.
RESULTS: The [Ca2+]i in hypoxic condition was markedly increased as compared with that in normoxic condition (293.2±12.4 nmol/L vs 137.7±7.8 nmol/L, P<0.01). In normoxic condition, the level of [Ca2+]i decreased sharply after 500, 800 and 1 000 mg/L octreotide treatment (92.52±2.52, 83.77±2.30 and 76.58±2.21 nmol/L, respectively, P<0.01); In hypoxic condition, 500, 800 and 1 000 mg/L octreotide caused significant reduction in [Ca2+]i(204.28±7.41, 174.08±4.77 and 156.75±6.59 nmol/L, respectively, P<0.01). MTT assay showed that 500, 800 and 1 000 mg/L octreotide reduced the value of optical density (A value) in normoxic (0.173±0.010, 0.138±0.009, 0.100±0.010, respectively) and hypoxic (0.443±0.027, 0.320±0.014, 0.230±0.014, respectively) condition. After exposure to hypoxic condition, the level of cAMP was not significantly different from that of cGMP (P>0.05). The contents of cAMP and cGMP markedly increased after 500, 800, and 1 000 μg/L octreotide treatment in normoxic (cAMP: 1.69±0.18, 1.99±0.27, 2.48±0.37 pmol/mg vs 1.10±0.32 pmol/mg, P<0.05 or P<0.01; cGMP: 1.08±0.24, 1.24±0.17, 1.31±0.29 pmol/mg vs 0.86±0.12 pmol/mg, P<0.05 or P<0.01) and hypoxic (cAMP: 1.87±0.30, 2.09±0.35, 2.24±0.15 pmol/mg vs 1.37±0.25 pmol/mg, P<0.05 or P<0.01; cGMP: 1.17±0.53, 1.38±0.29, 1.46±0.35 pmol/mg vs 0.89±0.20 pmol/mg, P<0.05 or P<0.01) condition as compared with those in the corresponding control groups.
CONCLUSION: Hypoxia can promote the proliferation of HSCs through the second messenger system, while octreotide antagonizes this action in a dose-dependant manner in both hypoxic and normoxic conditions. cAMP and cGMP play certain roles in the regulation of HSCs.
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Lang A, Sakhnini E, Fidder HH, Maor Y, Bar-Meir S, Chowers Y. Somatostatin inhibits pro-inflammatory cytokine secretion from rat hepatic stellate cells. Liver Int 2005; 25:808-16. [PMID: 15998432 DOI: 10.1111/j.1478-3231.2005.01057.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIMS Activated hepatic stellate cells (HSCs) have been implicated in hepatic fibrosis. Somatostatin (SOM) has an immunomodulatory role. The aim of this study was to assess the secretion of pro-inflammatory cytokines by HSCs and to determine the effect of SOM on the secretion of these mediators. METHODS Activated rat HSCs were evaluated for their secretion of IL-1beta, IL-8, and TNF-alpha using ELISA. RNA protection assay was used to determine cytokine mRNA levels. The expression of chemokine and cytokine mRNA and the secretion of these mediators were assessed following incubation with SOM or octreotide. RESULTS HSCs spontaneously secreted IL-1beta, IL-8, and TNF-alpha. This secretion was augmented following stimulation by IL-1beta and TNF-alpha. SOM inhibited the spontaneous and TNF-alpha-induced secretion of IL-1beta, IL-8, and TNF-alpha and suppressed the expression of IL-1beta and TNF-alpha mRNA. Octreotide suppressed the secretion of IL-1beta and IL-8. CONCLUSIONS These observations indicate that SOM exerts an inhibitory immunomodulatory effect on HSCs.
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Affiliation(s)
- Alon Lang
- Department of Gastroenterology and Liver Diseases, Chaim Sheba Medical Center, Tel-Hashomer, Israel.
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35
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Samonakis DN, Triantos CK, Thalheimer U, Patch DW, Burroughs AK. Management of portal hypertension. Postgrad Med J 2005; 80:634-41. [PMID: 15537846 PMCID: PMC1743143 DOI: 10.1136/pgmj.2004.020446] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Treatment of portal hypertension is evolving based on randomised controlled trials. In acute variceal bleeding, prophylactic antibiotics are mandatory, reducing mortality as well as preventing infections. Terlipressin or somatostatin combined with endoscopic ligation or sclerotherapy is the best strategy for control of bleeding but there is no added effect of vasoactive drugs on mortality. Non-selective beta-blockers are the first choice therapy for both secondary and primary prevention; if contraindications or intolerance to beta-blockers are present then band ligation should be used. Novel therapies target the increased intrahepatic resistance caused by microcirculatory intrahepatic deficiency of nitric oxide and contraction of activated intrahepatic stellate cells.
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Affiliation(s)
- D N Samonakis
- Liver Transplant and Hepatobiliary Medicine Unit, Royal Free Hospital, Pond Street, London NW3 2QG, UK.
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Song SH, Leng XS, Li T, Qin ZZ, Peng JR, Zhao L, Wei YH, Yu X. Expression of subtypes of somatostatin receptors in hepatic stellate cells. World J Gastroenterol 2004; 10:1663-5. [PMID: 15162546 PMCID: PMC4572775 DOI: 10.3748/wjg.v10.i11.1663] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To elucidate the mechanism by which somatostatin and its analogue exert the influence on liver fibrosis, and to investigate the mRNA expression of somatostatin receptors subtypes (SSTRs) and the distribution of somatostatin analogue octreotide in rat hepatic stellate cells (HSCs).
METHODS: HSCs were isolated from Sprague Dawley (SD) rats by in situ perfusion and density gradient centrifugation. After several passages, the mRNA expression of 5 subtypes of SSTRs were assessed by reverse transcription-polymerase chain reaction (RT-PCR). HSCs were planted on coverslip and co-cultured with octreotide tagged by FITC. Then the distribution of FITC fluorescence was observed under laser scanning confocal microscope (LSCM) in 12-24 h.
RESULTS: There were mRNA expression of SSTR2, SSTR3 and SSTR5 but not SSTR1 and SSTR4 in SD rat HSCs. The mRNA expression level of SSTR2 was significantly higher than that of other subtypes (P < 0.01). FITC fluorescence of octreotide was clearly observed on the surface and in the cytoplasm, but not in the nuclei of HSCs under LSCM.
CONCLUSION: The effect exerted by somatostatin and its analogues on HSCs may mainly depend on the expression of SSTR2, SSTR3 and SSTR5. Octreotide can perfectly combine with HSCs, and thereby exerts its biological activity on regulating the characters of active HSCs. This provides a potential prevention and management against liver fibrosis.
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Affiliation(s)
- Sheng-Han Song
- Department of Hepatobiliary Surgery, Peking University People's Hospital, Beijing 100044, China
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XiaoMing Z, Xi Z, Fang S, Jilin Z. Specific changes of somatostatin mRNA expression in the frontal cortex and hippocampus of diabetic rats. J Anat 2004; 204:221-5. [PMID: 15032912 PMCID: PMC1571256 DOI: 10.1111/j.0021-8782.2004.00273.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Abstract Most current studies of diabetic encephalopathy have focused on brain blood flow and metabolism, but there has been little research on the influence of diabetes on brain tissue and the causes of chronic diabetic encephalopathy. The technique of molecular biology makes it possible to explore the mechanism of chronic diabetic encephalopathy by testing the distribution of somatostatin in the brain. We have therefore analysed, by in situ hybridization histochemistry, the changes in somatostatin (SST) mRNA in the frontal cortex and hippocampus of rats made diabetic by the injection of streptozotocin. Ten Sprague-Dawley control rats were compared with ten streptozotocin-induced diabetic rats. The weight, blood glucose and urine glucose did not differ between the two groups before the injection of streptozotocin. Four weeks after the injection of streptozotocin the weight, blood glucose and urine glucose of the diabetic rats were, respectively, 199.1 +/- 15.6 g, 23.7 +/- 3.25 mmol L(-1) and (++) to (+++) whereas those of the control group were 265.5 +/- 30.3 g, 4.84 +/- 0.63 mmol L(-1) and (-). Somatostatin mRNA was reduced in the diabetic rats. The number of SST mRNA-positive neurons and the optical density of positive cells in the hippocampus and frontal cortex of the diabetic rats were 80.6 +/- 17.5 mm(-2) and 76.5 +/- 17.6 compared with 150.5 +/- 21.1 mm(-2) and 115.1 +/- 18.5 in the control rats. The induction of diabetes is thus associated with a decreased expression of SST mRNA in the hippocampus and frontal cortex, which might be an important component of chronic diabetic encephalopathy.
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Affiliation(s)
- Zhang XiaoMing
- Department of Anatomy, Zhejiang University Medical College, Hangzhou, People's Republic of China.
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Pan Q, Li DG, Lu HM, Lu LY, Wang YQ, Xu QF. Antiproliferative and proapoptotic effects of somatostatin on activated hepatic stellate cells. World J Gastroenterol 2004; 10:1015-8. [PMID: 15052685 PMCID: PMC4717091 DOI: 10.3748/wjg.v10.i7.1015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To assess the effects of somatostatin on proliferation and apoptosis of activated rat hepatic stellate cells (HSCs).
METHODS: HSCs isolated from the livers of adult Sprague-Dawley rats (weighing 400-500 g) by in situ perfusion and purified by single-step density gradient centrifugation with Nycodenz, became activated after 10 days’ cultivation. Then the apoptotic rate of HSCs treated with different doses of somatostatin for 72 h, was assayed by acridine orange/ ethidium bromide fluorescent staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, transmission electron microscopy and flow cytometry, while the proliferation of HSCs was measured by MTT assay. Furthermore, the mechanisms of somatostatin were investigated by cytodynamic analysis.
RESULTS: Somatostatin at the concentration of 10-6-10-9 mol/L could decrease the proliferative rate, and promote the apoptosis of activated rat HSCs in a dose-dependent way. Its action was most significant when the concentration reached 10-6 mol/L or 10-7 mol/L (P < 0.05-0.01). An obvious cell-cycle arrest (G0/G1 arrest) was the important way for somatostatin to exert its action.
CONCLUSION: Antiproliferative and proapoptotic effects of low-dose somatostatin on activated rat HSCs can be obtained. These findings reveal its potential antifibrotic action.
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Affiliation(s)
- Qin Pan
- Department of Gastroenterology, Shanghai Second Medical University, Xinhua Hospital, 1665 KongJiang Rd., Shanghai 200092, China.
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Uyama N, Geerts A, Reynaert H. Neural connections between the hypothalamus and the liver. ACTA ACUST UNITED AC 2004; 280:808-20. [PMID: 15382020 DOI: 10.1002/ar.a.20086] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
After receiving information from afferent nerves, the hypothalamus sends signals to peripheral organs, including the liver, to keep homeostasis. There are two ways for the hypothalamus to signal to the peripheral organs: by stimulating the autonomic nerves and by releasing hormones from the pituitary gland. In order to reveal the involvement of the autonomic nervous system in liver function, we focus in this study on autonomic nerves and neuroendocrine connections between the hypothalamus and the liver. The hypothalamus consists of three major areas: lateral, medial, and periventricular. Each area has some nuclei. There are two important nuclei and one area in the hypothalamus that send out the neural autonomic information to the peripheral organs: the ventromedial hypothalamic nucleus (VMH) in the medial area, the lateral hypothalamic area (LHA), and the periventricular hypothalamic nucleus (PVN) in the periventricular area. VMH sends sympathetic signals to the liver via the celiac ganglia, the LHA sends parasympathetic signals to the liver via the vagal nerve, and the PVN integrates information from other areas of the hypothalamus and sends both autonomic signals to the liver. As for the afferent nerves, there are two pathways: a vagal afferent and a dorsal afferent nerve pathway. Vagal afferent nerves are thought to play a role as sensors in the peripheral organs and to send signals to the brain, including the hypothalamus, via nodosa ganglia of the vagal nerve. On the other hand, dorsal afferent nerves are primary sensory nerves that send signals to the brain via lower thoracic dorsal root ganglia. In the liver, many nerves contain classical neurotransmitters (noradrenaline and acetylcholine) and neuropeptides (substance P, calcitonin gene-related peptide, neuropeptide Y, vasoactive intestinal polypeptide, somatostatin, glucagon, glucagon-like peptide, neurotensin, serotonin, and galanin). Their distribution in the liver is species-dependent. Some of these nerves are thought to be involved in the regulation of hepatic function as well as of hemodynamics. In addition to direct neural connections, the hypothalamus can affect metabolic functions by neuroendocrine connections: the hypothalamus-pancreas axis, the hypothalamus-adrenal axis, and the hypothalamus-pituitary axis. In the hypothalamus-pancreas axis, autonomic nerves release glucagon and insulin, which directly enter the liver and affect liver metabolism. In the hypothalamus-adrenal axis, autonomic nerves release catecholamines such as adrenaline and noradrenaline from the adrenal medulla, which also affects liver metabolism. In the hypothalamus-pituitary axis, release of glucocorticoids and thyroid hormones is stimulated by pituitary hormones. Both groups of hormones modulate hepatic metabolism. Taken together, the hypothalamus controls liver functions by neural and neuroendocrine connections.
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Affiliation(s)
- Naoki Uyama
- Laboratory for Molecular Liver Cell Biology, Vrije Universiteit Brussel, Belgium.
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Reynaert H, Geerts A. Pharmacological rationale for the use of somatostatin and analogues in portal hypertension. Aliment Pharmacol Ther 2003; 18:375-86. [PMID: 12940922 DOI: 10.1046/j.1365-2036.2003.01657.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Somatostatin and its analogue octreotide have been used for two decades to treat oesophageal variceal haemorrhage. The drug was introduced because of its capacity to decrease portal venous pressure without major side effects. In clinical trials assessing the efficacy of somatostatin and long-acting analogues in arresting variceal haemorrhage, conflicting results have been obtained. Furthermore, in haemodynamic studies evaluating the effects of somatostatin and analogues in patients with cirrhosis, divergent effects were observed. The main reason for these differences is probably related to different affinities of the drugs for different somatostatin receptor subtypes. The effects of somatostatin and analogues are mediated via five different G-protein coupled receptors (somatostatin receptor subtypes 1-5), which regulate the activity of ion channels (Ca2+, K+, Na+ and Cl-) and enzymes (adenyl cyclase, phospholipase C, phospholipase A2, phosphoinositide 3-kinase and guanylate cyclase) responsible for the synthesis or degradation of intracellular second messengers including cyclic AMP, inositol 1,4,5-trisphosphate, diacylglycerol and cyclic GMP. Despite universal use of somatostatin, the cellular and biochemical mechanisms of its effects in portal hypertension are relatively poorly studied and remain incompletely understood. In this review, we summarize relevant signal transduction of somatostatin and analogues, the haemodynamic effects of the drugs and the possible mechanisms by which these effects are mediated.
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Affiliation(s)
- H Reynaert
- Department of Gastroenterology-Hepatology, University Hospital AZ-VUB and Laboratory for Molecular Liver Cell Biology, Vrije Universiteit Brussel, Brussels, Belgium.
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Rombouts K, Kisanga E, Hellemans K, Wielant A, Schuppan D, Geerts A. Effect of HMG-CoA reductase inhibitors on proliferation and protein synthesis by rat hepatic stellate cells. J Hepatol 2003; 38:564-72. [PMID: 12713866 DOI: 10.1016/s0168-8278(03)00051-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND/AIMS 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors called statins, have besides their cholesterol-lowering function, therapeutic value in conditions such as neo-angiogenesis and atherosclerosis. We investigated the effect of two statins on the proliferation rate and protein steady state levels of hepatic stellate cells (HSC). METHODS Cellular DNA synthesis under the influence of statins and/or platelet derived growth factor (PDGF) and mevalonate was evaluated by measuring BrdU incorporation. Synthesis of collagens type I, III, IV and fibronectin was quantified by ELISA. Additionally, we examined the influence of simvastatin on isoprenylation of Ras and RhoA proteins. RESULTS Lovastatin and simvastatin induced a dose-dependent inhibition of the proliferation rate of HSC. Subsequent addition of PDGF and/or mevalonate, after long-term exposure of simvastatin to HSC, did not reverse simvastatins' antiproliferative effect. Lovastatin and simvastatin reduced the protein steady state level of collagens type I (-40%), III (-45%) and IV (-27%). Membrane bound Ras steady state levels decreased under the influence of simvastatin. Membrane bound RhoA remained unaltered, whereas, cytosolic RhoA protein level was strongly reduced. CONCLUSIONS Our data showed that lovastatin and simvastatin inhibited HSC proliferation and collagen steady state levels by mechanisms independent of their lipid reducing activities.
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Affiliation(s)
- Krista Rombouts
- Laboratory for Molecular Liver Cell Biology, Faculty of Medicine and Pharmacy, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels-Jette, Belgium.
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Cervia D, Zizzari P, Pavan B, Schuepbach E, Langenegger D, Hoyer D, Biondi C, Epelbaum J, Bagnoli P. Biological activity of somatostatin receptors in GC rat tumour somatotrophs: evidence with sst1-sst5 receptor-selective nonpeptidyl agonists. Neuropharmacology 2003; 44:672-85. [PMID: 12668053 DOI: 10.1016/s0028-3908(03)00031-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The physiological actions of somatostatin-14 (SRIF: somatotrophin release inhibitory factor) receptor subtypes (sst(1)-sst(5)), which are endogenously expressed in growth cells (GC cells), have not yet been elucidated, although there is evidence that sst(2) receptors are negatively coupled to cytosolic free Ca(2+) concentration ([Ca(2+)](i)) and adenosine 3,5'-cyclic monophosphate (cAMP) accumulation. In addition, both sst(1) and sst(2) receptors are negatively coupled to growth hormone (GH) secretion in GC cells. Here we report on studies concerning the expression, the pharmacology and the functional role of native SRIF receptors in GC cells with the use of five nonpeptidyl agonists, highly selective for each of the SRIF receptors. Radioligand binding studies show that sst(2) and sst(5) receptors are present at different relative densities, while the presence of sst(3) and sst(4) receptors appears to be negligible. The absence of sst(1) receptor binding was unexpected in view of sst(1) receptor functional effects on GH secretion. This suggests very efficient receptor-effector coupling of a low-density population of sst(1) receptors. Functionally, only sst(2) receptors are coupled to the inhibition of [Ca(2+)](i) and cAMP accumulation and the selective activation of sst(5) receptors facilitates the stimulation of adenylyl cyclase activity through G(i/o) proteins. This effect was not observed when sst(2) and sst(5) receptors were simultaneously activated, suggesting that there is a functional interaction between sst(2) and sst(5) receptors. In addition, sst(1), sst(2) and sst(5) receptor activation inhibits GH release, further indicating that SRIF can modulate GH secretion in GC cells through mechanisms both dependent and independent on [Ca(2+)](i) and cAMP-dependent pathways. The present data suggest SRIF-mediated functional effects in GC cells to be very diverse and provides compelling arguments to propose that multiple native SRIF receptors expressed in the same cells are not simply redundant, but contribute to marked signalling diversity.
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Affiliation(s)
- D Cervia
- Dipartimento di Fisiologia e Biochimica G. Moruzzi, Università di Pisa, Italy.
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Man K, Fan ST, Lo CM, Liu CL, Fung PCW, Liang TB, Lee TKW, Tsui SHT, Ng IOL, Zhang ZW, Wong J. Graft injury in relation to graft size in right lobe live donor liver transplantation: a study of hepatic sinusoidal injury in correlation with portal hemodynamics and intragraft gene expression. Ann Surg 2003; 237:256-64. [PMID: 12560784 PMCID: PMC1522144 DOI: 10.1097/01.sla.0000048976.11824.67] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To investigate the degree and mechanism of hepatic sinusoidal injury in different graft sizes in right lobe live donor liver transplantation (LDLT). SUMMARY BACKGROUND DATA Liver grafts from living donors are likely to be small-for-size for adult recipients. Graft injury after reperfusion is common, but the mechanism and degree of injury remain unclear. The hepatic sinusoidal injury in different graft sizes and its relationship with portal hemodynamics and intragraft gene response at the early phase after reperfusion have not been studied in right lobe LDLT. METHODS From May 2000 to November 2001, 40 adults receiving right lobe LDLT had portal pressure measured continuously before and after reperfusion. Liver biopsies were taken before and after reperfusion for detection of vasoregulatory genes (endothelin-1 and endothelial nitric oxide synthase) and heat shock genes (heat shock protein 70 and heme oxygenase-1), and electron microscope examination. Blood samples from the portal vein and suprahepatic inferior vena cava were taken for the measurement of plasma nitric oxide level. RESULTS The recipients were grouped according to the ratio of graft weight to estimated standard liver weight: group 1 (n = 10), less than 40%; group 2 (n = 21), 40% to 60%; and group 3 (n = 9), more than 60%. The portal pressures recorded after reperfusion in group 1 were significantly higher within 30 minutes of reperfusion than those in groups 2 and 3. After reperfusion, the intragraft endothelin-1 mRNA level in group 1 increased by 161% of the basal level but decreased by 31.5% and 62% of the basal level in groups 2 and 3, respectively. The intragraft mRNA level of heme oxygenase-1 in groups 1 and 2 decreased by 75.5% and 25.3% of the basal level respectively but increased by 41% of basal level in group 3. The intragraft protein level of heat shock protein 70 decreased by 50 ng/mL after reperfusion in group 1 but increased by 12.4 ng/mL and 0.6 ng/mL in groups 2 and 3, respectively. The portal vein plasma nitric oxide level decreased more significantly after reperfusion in group 1 than in group 2. Electron microscope examination of liver biopsies in group 1 showed tremendous mitochondrial swelling as well as irregular large gaps between the sinusoidal lining cells. There were two hospital deaths in group 1 and none in the other two groups. CONCLUSIONS Patients implanted with grafts less than 40% of standard liver weight suffered from transient portal hypertension early after reperfusion. The phenomenon was accompanied by intragraft upregulation of endothelin-1 and ultrastructural evidence of sinusoidal damage. The transient portal hypertension after reperfusion, subsequent endothelin-1 overexpression, and plasma nitric oxide level reduction, together with downregulation of heme oxygenase-1 and heat shock protein 70, may account for the small-for-size graft injury.
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Affiliation(s)
- Kwan Man
- Centre for the Study of Liver Disease and Department of Surgery, University of Hong Kong Medical Centre, Queen Mary Hospital, Hong Kong SAR, China
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Affiliation(s)
- Don C Rockey
- Department of Medicine and The Liver Center, Duke University Medical Center, Durham, NC 27710, USA.
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Rombouts K, Knittel T, Machesky L, Braet F, Wielant A, Hellemans K, De Bleser P, Gelman I, Ramadori G, Geerts A. Actin filament formation, reorganization and migration are impaired in hepatic stellate cells under influence of trichostatin A, a histone deacetylase inhibitor. J Hepatol 2002; 37:788-96. [PMID: 12445420 DOI: 10.1016/s0168-8278(02)00275-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS Previously, trichostatin A (TSA), a histone deacetylase inhibitor, has been shown to exhibit strong antifibrotic characteristics in hepatic stellate cells (HSC), which are known to play a central role in chronic liver diseases. TSA retained a more quiescent phenotype in spite of culture conditions that favor transdifferentiation into activated HSC. METHODS To identify TSA-sensitive genes, differential mRNA display, Northern and Western blot analysis were used and genes were functionally validated by using contraction and motility assays. RESULTS TSA prevented new actin filament formation by down-regulation of two nucleating proteins, actin related protein 2 (Arp2) and Arp3, and by up-regulation of adducin like protein 70 (ADDL70) and gelsolin, two capping proteins. RhoA, a key mediator in the development of the actin cytoskeleton, decreased following TSA exposure. Expression of proteins of Class III intermediate filaments was affected by TSA. Furthermore, F-actin and G-actin were expressed heterogeneously under influence of TSA. Functionally, TSA treatment abrogated migration of quiescent HSC, while migration was reduced in transitional HSC. The endothelin-1-induced contractility properties of HSC was not affected by TSA. CONCLUSIONS These data indicate that TSA affects the development of the actin cytoskeleton in quiescent HSC and thereby abrogates the process of HSC transdifferentiation.
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Affiliation(s)
- Krista Rombouts
- Laboratory for Molecular Liver Cell Biology, Faculty of Medicine and Pharmacy, Free University of Brussels (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium.
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Reinehr R, Fischer R, Häussinger D. Regulation of endothelin-A receptor sensitivity by cyclic adenosine monophosphate in rat hepatic stellate cells. Hepatology 2002; 36:861-73. [PMID: 12297833 DOI: 10.1053/jhep.2002.35623] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Sensitization of the endothelin-A receptor (ET(A)) occurs during HSC transdifferentiation, but the underlying mechanisms remained unclear. Sensitization of ET(A) was studied in quiescent and activated hepatic stellate cells (HSC) at the levels of receptor phosphorylation, localization, endothelin (ET)-1-induced Ca(2+) signals, and cell contraction. The endothelin-1 (ET-1) concentrations required to obtain an ET(A)-mediated Ca(2+) signal in 50% of HSC cultured for 1 to 2 or 10 days were approximately 1.2 and 0.012 nmol/L, respectively. This transdifferentiation-dependent sensitization of ET(A) was accompanied by receptor translocation to the plasma membrane. Cyclic AMP rapidly desensitized ET(A) in activated HSC and shifted their ET-1 responsiveness from picomolar to nanomolar concentrations with respect to Ca(2+) signals and HSC contraction. ET(A) desensitization also occurred in response to prostaglandin E(2), adenosine, or ET(B) stimulation. Desensitization by cAMP in activated HSC was accompanied by an increased Ser/Thr phosphorylation of ET(A) and their rapid internalization. Quiescent HSC exhibited Ser/Thr phosphorylation of the ET(A) protein, which was not affected by cAMP. In conclusion, the ET(A) response in HSC is regulated by protein kinase A (PKA)-dependent receptor phosphorylation and internalization. This may explain the transdifferentiation-dependent sensitization of HSC towards ET-1 and its reversal by cAMP and ET(B) activation.
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Affiliation(s)
- Roland Reinehr
- Clinic for Gastroenterology, Hepatology, and Infectiology, Heinrich-Heine-Universität, Düsseldorf, Germany
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Chatterjee S, Mbaye A, De Man JG, Van Marck EAE. Does the neuropeptide somatostatin have therapeutic potential against schistosomiasis? Trends Parasitol 2002; 18:295-8. [PMID: 12379948 DOI: 10.1016/s1471-4922(02)02294-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The neuropeptide hormone somatostatin is used to treat bleeding oesophageal varices and to reduce portal pressure, and can prevent progression to severe fibrosis in chronic liver disease. We believe that somatostatin can also have therapeutic potential against schistosomiasis, based on recent observations that severe morbidity symptoms are associated with low levels of host somatostatin in patients infected with Schistosoma mansoni. The administration of exogenous doses of this neuropeptide could therefore alleviate the pathology caused by schistosomiasis.
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Affiliation(s)
- Shyama Chatterjee
- Pathology Unit, Dept of Medicine, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium.
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Affiliation(s)
- Juan G Abraldes
- Hepatic Hemodynamic Laboratory, Liver Unit, Hospital Clinic, Barcelona, Spain
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