Stress triggers disorders in accelerated peristalsis, with corticotropin releasing factor receptor 1 (CRF-R1) playing a pivotal role. Enteric glia cells (EGCs) and glial Cx43 are known to influence gastrointestinal motility, yet their involvement in colonic motor responses to stress remains unclear. Using immunofluorescence and single-cell RNA sequencing data, we identified CRF-R1 expression in EGCs. Male C57BL/6 mice subjected to wrap restraint stress (WRS) revealed stress-induced colonic motility changes. By employing Fluoroacetate, NBI 27914, and Gap26, we elucidated the impact of glial CRF-R1/Cx43 on stress-induced colonic motor responses. Our study demonstrated CRF-R1 expression in EGCs of the small intestine and colon, along with elevated CRF levels and upregulated CRF-R1 in the distal colon under stress. Antagonizing CRF-R1 and disrupting EGC function made mice resistant to colonic stress responses. Mechanistically, increased glial Cx43 expression and activity influenced colonic motor responses in a CRF-R1-dependent manner. Our findings highlight the role of EGC-derived CRF-R1 in stress-induced colonic motor responses via Cx43 activation. Targeting CRF-R1/Cx43 signaling in EGCs may offer a promising approach to mitigate stress-induced colonic transit changes.

Constipation is a common gastrointestinal disorder characterized by infrequent bowel movements and difficulty in passing stools. It can significantly affect an individual's quality of life and overall well-being. Understanding the causes of constipation is important for its effective management and treatment. In this paper, we have reviewed the primary causes of constipation or functional constipation. Primary constipation is a bowel disorder associated with colonic or anorectal sensorimotor or neuromuscular dysfunction. As per the literature, it is multifactorial and involves factors such as decreased interstitial cells of Cajal, altered colonic motility, enteric nervous system dysfunction, intestinal flora disturbances, and psychological influences. Clinical symptoms include difficulty in defecation, decreased frequency of defecation, or a feeling of incomplete evacuation. A comprehensive evaluation and management of constipation require an interdisciplinary approach incorporating dietary modifications, lifestyle changes, pharmacotherapy, and psychological interventions. Further research is imperative to explain the intricate mechanisms underlying constipation and develop targeted therapies for improved patient outcomes.

Enteric glial cells (EGCs) are the major component of the enteric nervous system and affect the pathophysiological process of intestinal motility dysfunction. MicroRNAs (miRNAs) play an important role in regulating gastrointestinal homeostasis. However, the mechanism of miRNA-mediated regulation of EGCs in intestinal dysmotility remains unclear. In this study, we investigated the effect of EGC apoptosis on intestinal dysmotility, and the effect of miR-26b-3p on EGC proliferation and apoptosis in vivo and in vitro. A loperamide hydrochloride (Lop)-induced constipated mouse model and an in vitro culture system of rat EGCs were established. The transcriptome was used to predict the differentially expressed gene miR-26b-3p and the target gene Frizzled 10 (FZD10), and their targeting binding relationship was verified by luciferase. EGCs were transfected with miR-26b-3p mimic or antagomir, and the FZD10 expression was down-regulated by siRNA. Immunofluorescence and flow cytometry were used to detect EGC apoptosis. MiR-26b-3p and FZD10 expressions were examined using quantitative real-time PCR (qRT-PCR). The CCK-8 assay was used to detect EGC proliferation. The protein levels were detected by Western blotting and enzyme-linked immunosorbent assay (ELISA). The results showed that miR-26b-3p was up-regulated in the Lop group, whereas FZD10 was down-regulated, and EGC apoptosis was increased in the colon of intestinal dysmotility mice. FZD10 down-regulation and miR-26b-3p mimic significantly increased glycogen synthase kinase-3β phosphorylation (p-GSK3β) levels, decreased β-catenin expression, and promoted EGC apoptosis. MiR-26b-3p antagomir alleviated intestinal dysmotility, promoted EGC increased activity of EGCs, and reduced EGC apoptosis in vivo. In conclusion, this study indicated that miR-26b-3p promotes intestinal motility disorders by targeting FZD10 to block GSK3β/β-catenin signaling and induces apoptosis in EGCs. Our results provide a new research target for the treatment and intervention of intestinal dysmotility.

Constipation is a prevalent gastrointestinal symptom that can considerably affect a patients' quality of life. Although several drugs have been used to treat constipation, they are associated with high costs, side effects, and low universality. Therefore, alternative intervention strategies are urgently needed. Traditional lactic acid bacteria (LAB), such as Bifidobacterium and Lactobacillus, play a vital role in regulating intestinal microecology and have demonstrated favorable effects in constipation; however, a comprehensive review of their constipation relief mechanisms is limited. This review summarizes the pathogenesis of constipation and the relationship between intestinal motility and gut microbiota, elucidates the possible mechanism by which LAB alleviates of constipation through a systematic summary of animal and clinical research, and highlights the challenges and applications of LAB in the treatment of constipation. Our review can improve our understanding of constipation, and advance targeted microecological therapeutic agents, such as LAB.

Chronic constipation is a frequent symptom encountered in the daily clinical practice. The treatment of this condition mainly relies on the use of laxatives. However, patients' satisfaction with this approach is limited, and alternative measures are often added to the treatment. Among these, particularly frequent worldwide is the use of enemas, even though literature data on its scientific validity are scarce.

In this article, by an extensive online search of Medline (through PubMed), Scopus, Cochrane CENTRAL, EMBASE, and the Science Citation Index, the available literature data on the use of enemas in adult patients with chronic constipation, also in the perspective of available guidelines on treatment of this pathological condition, were analyzed.

Although the use of enemas remains a frequently employed method and it is considered as useful by many physicians as an adjunctive support for the treatment of chronic constipation in adults, this practice is not substantiated by rigorous scientific data, and some studies are available only for specific instances (fecal impaction, transanal irrigation). Thus, waiting for more robust scientific data, enemas treatment should be carried out on an individual patient's basis, according to the experience of the caring physicians.

Slow transit constipation (STC) is a common gastrointestinal disorder seriously impacting patients' quality of life. At present, although conventional chemical drugs effectively control STC symptoms in the short term, the long-term effects are poor, and the side effects are significant. In this regard, traditional Chinese medicine (TCM) offers an opportunity for STC treatment. Many pharmacological and clinical studies have confirmed this efficacy of TCM with multiple targets and mechanisms.

This review attempted to summarize the characteristics of TCM (compound prescriptions, single Chinese herbs, and active ingredients) for STC treatment and discussed their efficacy based on analyzing the pathogenesis of STC.

The information was acquired from different databases, including PubMed, Web of Science, China National Knowledge Infrastructure, and Wanfang databases. We then focused on the recent research progress in STC treatment by TCM. Finally, the future challenges and trends are proposed.

TCM has good clinical efficacy in the treatment of STC with multi-mechanisms. Based on the theory of syndrome differentiation, five kinds of dialectical treatment for STC by compound TCM prescriptions were introduced, namely: Nourishing Yin and moistening the intestines; Promoting blood circulation and removing blood stasis; Warming Yang and benefiting Qi; Soothing the liver and regulating Qi; and Benefiting Qi and strengthening the spleen. In addition, six single Chinese herbs and eight active ingredients also show good efficacy in STC treatment.

TCM, especially compound prescriptions, has bright prospects in treating STC attributed to its various holistic effects.

Chronic kidney disease (CKD) produces multiple repercussions in the gastrointestinal tract (GIT), such as alterations in motility, gut microbiota, intestinal permeability, and increased oxidative stress. However, despite enteric glial cells (EGC) having important neural and immune features in GIT physiology, their function in CKD remains unknown. The present study investigates colonic glial markers, inflammation, and antioxidant parameters in a CKD model.

A 5/6 nephrectomized rat model was used to induce CKD in rats and Sham-operated animals as a control to suppress. Biochemical measures in plasma and neuromuscular layer such as glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were carried out. Kidney histopathology was evaluated. Colon morphology analysis and glial fibrillary acid protein (GFAP), connexin-43 (Cx43), nuclear factor-kappa B (NF-κB) p65, and GPx protein expression were performed.

The CKD group exhibited dilated tubules and tubulointerstitial fibrosis in the reminiscent kidney (p = 0.0002). CKD rats showed higher SOD activity (p = 0.004) in plasma, with no differences in neuromuscular layer (p = 0.9833). However, GPx activity was decreased in the CKD group in plasma (p = 0.013) and neuromuscular layer (p = 0.0338). Morphological analysis revealed alterations in colonic morphometry with inflammatory foci in the submucosal layer and neuromuscular layer straightness in CKD rats (p = 0.0291). In addition, GFAP, Cx43, NF-κBp65 protein expression were increased, and GPx decreased in the neuromuscular layer of the CKD group (p < 0.05).

CKD animals present alterations in colonic cytoarchitecture and decreased layer thickness. Moreover, CKD affects the enteric glial network of the neuromuscular layer, associated with decreased antioxidant activity and inflammation.

The act of defaecation, although a ubiquitous human experience, requires the coordinated actions of the anorectum and colon, pelvic floor musculature, and the enteric, peripheral and central nervous systems. Defaecation is best appreciated through the description of four phases, which are, temporally and physiologically, reasonably discrete. However, given the complexity of this process, it is unsurprising that disorders of defaecation are both common and problematic; almost everyone will experience constipation at some time in their life and many will develop faecal incontinence. A detailed understanding of the normal physiology of defaecation and continence is critical to inform management of disorders of defaecation. During the past decade, there have been major advances in the investigative tools used to assess colonic and anorectal function. This Review details the current understanding of defaecation and continence. This includes an overview of the relevant anatomy and physiology, a description of the four phases of defaecation, and factors influencing defaecation (demographics, stool frequency/consistency, psychobehavioural factors, posture, circadian rhythm, dietary intake and medications). A summary of the known pathophysiology of defaecation disorders including constipation, faecal incontinence and irritable bowel syndrome is also included, as well as considerations for further research in this field.

Chemotherapy is a first-line treatment for many cancers; however, its use is hampered by a long list of side-effects. Gastrointestinal mucositis is a common and debilitating side-effect of anticancer therapy contributing to dose reductions, delays and cessation of treatment, greatly impacting clinical outcomes. The underlying pathophysiology of gastrointestinal mucositis is complex and likely involves several overlapping inflammatory, secretory and neural mechanisms, yet research investigating the role of innervation in gastrointestinal mucositis is scarce. This review provides an overview of the current literature surrounding chemotherapy-induced enteric neurotoxicity and discusses its implications on gastrointestinal mucositis.

Damage to the intrinsic nervous system of the gastrointestinal tract, the enteric nervous system (ENS), occurs following chemotherapeutic administration, leading to altered gastrointestinal functions. Chemotherapeutic drugs have various mechanisms of actions on the ENS. Oxidative stress, direct toxicity and inflammation have been identified as mechanisms involved in chemotherapy-induced ENS damage. Enteric neuroprotection has proven to be beneficial to reduce gastrointestinal dysfunction in animal models of oxaliplatin-induced enteric neuropathy.

Understanding of the ENS role in chemotherapy-induced mucositis requires further investigation and might lead to the development of more effective therapeutic interventions for prevention and treatment of chemotherapy-induced gastrointestinal side-effects.

Parkinson's disease (PD) is associated with neuronal damage in the brain and gut. This work compares changes in the enteric nervous system (ENS) of commonly used mouse models of PD that exhibit central neuropathy and a gut phenotype. Enteric neuropathy was assessed in five mouse models: peripheral injection of MPTP; intracerebral injection of 6-OHDA; oral rotenone; and mice transgenic for A53T variant human α-synuclein with and without rotenone. Changes in the ENS of the colon were quantified using pan-neuronal marker, Hu, and neuronal nitric oxide synthase (nNOS) and were correlated with GI function. MPTP had no effect on the number of Hu+ neurons but was associated with an increase in Hu+ nuclear translocation (P < 0.04). 6-OHDA lesioned mice had significantly fewer Hu+ neurons/ganglion (P < 0.02) and a reduced proportion of nNOS+ neurons in colon (P < 0.001). A53T mice had significantly fewer Hu+ neurons/area (P < 0.001) and exhibited larger soma size (P < 0.03). Treatment with rotenone reduced the number of Hu+ cells/mm2 in WT mice (P < 0.006) and increased the proportion of Hu+ translocated cells in both WT (P < 0.02) and A53T mice (P < 0.04). All PD models exhibited a degree of enteric neuropathy, the extent and type of damage to the ENS, however, was dependent on the model.

Gastroparesis (Gp) is a chronic disease characterized by a delayed gastric emptying in the absence of mechanical obstruction. Although this condition has been reported in the literature since the mid-1900s, only recently has there been renewed clinical and scientific interest in this disease, which has a potentially great impact on the quality of life. The aim of this review is to explore the pathophysiological, diagnostic and therapeutical aspects of Gp according to the most recent evidence. A comprehensive online search for Gp was carried out using MEDLINE and EMBASE. Gp is the result of neuromuscular abnormalities of the gastric motor function. There is evidence that patients with idiopathic and diabetic Gp may display a reduction in nitrergic inhibitory neurons and in interstitial cells of Cajal and/or telocytes. As regards diagnostic approach, 99-Technetium scintigraphy is currently considered to be the gold standard for Gp. Its limits are a lack of standardization and a mild risk of radiation exposure. The C13 breath testing is a valid and safe alternative method. 13C acid octanoic and the 13C Spirulina platensis recently approved by the Food and Drug Administration are the most commonly used diagnostic kits. The wireless motility capsule is a promising technique, but its use is limited by costs and scarce availability in many countries. Finally, therapeutic strategies are related to the clinical severity of Gp. In mild and moderate Gp, dietary modification and prokinetic agents are generally sufficient. Metoclopramide is the only drug approved by the Food and Drug Administration for Gp. However, other older and new prokinetics and antiemetics can be considered. As a second-line therapy, tricyclic antidepressants and cannabinoids have been proposed. In severe cases the normal nutritional approach can be compromised and artificial nutrition may be needed. In drug-unresponsive Gp patients some alternative strategies (endoscopic, electric stimulation or surgery) are available.

Clostridium difficile infection (CDI) causes nosocomial/antibiotic-associated diarrhea and pseudomembranous colitis, with dramatic incidence/mortality worldwide. C. difficile virulence factors are toxin A and toxin B (TcdB) which cause cytopathic/cytotoxic effects and inflammation. Until now studies were focused on molecular effects of C. difficile toxins (Tcds) on different cells while unexplored aspect is the status/fate of cells that survived their cytotoxicity. Recently we demonstrated that enteric glial cells (EGCs) are susceptible to TcdB cytotoxicity, but several EGCs survived and were irreversibly cell-cycle arrested and metabolically active, suggesting that EGCs could became senescent. This is important because allowed us to evaluate the not explored status/fate of cells surviving Tcds cytotoxicity, and particularly if TcdB induces senescence in EGCs. Rat-transformed EGCs were treated with 10 ng/ml TcdB for 6 h-48 h, or for 48 h, followed by incubation for additional 4 or 11 days in absence of TcdB (6 or 13 total days). Senescence markers/effectors were examined by specific assays. TcdB induces senescence in EGCs, as demonstrated by the senescence markers: irreversible cell-cycle arrest, senescence-associated-β‑galactosidase positivity, flat morphology, early and persistent DNA damage (ATM and H2AX phosphorylation), p27 overexpression, pRB hypophosphorylation, c‑Myc, cyclin B1, cdc2 and phosphorylated-cdc2 downregulation, Sirtuin‑2 and Sirtuin‑3 overexpression. TcdB-induced EGC senescence is dependent by JNK and AKT activation but independent by ROS, p16 and p53/p21 pathways. In conclusion, TcdB induces senescence in EGCs. The extrapolation of these results to CDI leads to hypothesize that EGCs that survived TcdB, once they have acquired a senescence state, could cause irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and tumors due to persistent inflammation, transfer of senescence status and stimulation of pre-neoplastic cells.

Cisplatin, carboplatin and oxaliplatin represent the backbone of platinum therapy for several malignancies including head and neck, lung, colorectal, ovarian, breast, and genitourinary cancer. However, the efficacy of platinum-based drugs is often compromised by a plethora of severe toxicities including sensory and enteric neuropathy. Acute and chronic neurotoxicity following platinum chemotherapy is a major constraint, contributing to dose-reductions, treatment delays, and cessation of treatment. Identifying drugs that effectively prevent these toxic complications is imperative to improve the efficacy of anti-cancer treatment and patient quality of life. Oxidative stress and mitochondrial dysfunction have been highlighted as key players in the pathophysiology of platinum chemotherapy-induced neuropathy. Inhibition of poly(ADP-ribose) polymerase (PARP), a nuclear enzyme activated upon DNA damage, has demonstrated substantial sensory and enteric neuroprotective capacity when administered in combination with platinum chemotherapeutics. Furthermore, administration of PARP inhibitors alongside platinum chemotherapy has been found to significantly improve progression-free survival in patients with breast and ovarian cancer when compared to those receiving chemotherapy alone. This review summarises the current knowledge surrounding mitochondrial damage and oxidative stress in platinum chemotherapy-induced neuropathy and highlights a potential role for PARP in chemopotentiation and neuroprotection.

Enteric glial cells (EGCs) are components of the enteric nervous system, an organized structure that controls gut functions. EGCs may be vulnerable to different agents, such as bacterial infections that could alter the intestinal epithelial barrier, allowing bacterial toxins and/or other agents possessing intrinsic toxic effect to access cells. Palmitate, known to exhibit lipotoxicity, is released in the gut during the digestion process. In this study, we investigated the lipotoxic effect of palmitate in cultured EGCs, with particular emphasis on palmitate-dependent intracellular lipid remodeling. Palmitate but not linoleate altered mitochondrial and endoplasmic reticulum lipid composition. In particular, the levels of phosphatidic acid, key precursor of phospholipid synthesis, increased, whereas those of mitochondrial cardiolipin (CL) decreased; in parallel, phospholipid remodeling was induced. CL remodeling (chains shortening and saturation) together with palmitate-triggered mitochondrial burst, caused cytochrome c (cyt c) detachment from its CL anchor and accumulation in the intermembrane space as soluble pool. Palmitate decreased mitochondrial membrane potential and ATP levels, without mPTP opening. Mitochondrial ROS permeation into the cytosol and palmitate-induced ER stress activated JNK and p38, culminating in Bim and Bax overexpression, factors known to increase the outer mitochondrial membrane permeability. Overall, in EGCs palmitate produced weakening of cyt c-CL interactions and favoured the egress of the soluble cyt c pool outside mitochondria to trigger caspase-3-dependent viability loss. Elucidating the mechanisms of palmitate lipotoxicity in EGCs may be relevant in gut pathological conditions occurring in vivo such as those following an insult that may damage the intestinal epithelial barrier.

Post-infectious irritable bowel syndrome is a well-defined pathological entity that develops in about one-third of subjects after an acute infection (bacterial, viral) or parasitic infestation. Only recently it has been documented that an high incidence of post-infectious irritable bowel syndrome occurs after Clostridium difficile infection. However, until now it is not known why in some patients recovered from this infection the gastrointestinal disturbances persist for months or years. Based on our in vitro studies on enteric glial cells exposed to the effects of C. difficile toxin B, we hypothesize that persistence of symptoms up to the development of irritable bowel syndrome might be due to a disturbance/impairment of the correct functions of the enteroglial intestinal network.

Constipation is a common non-motor symptom of Parkinson's disease (PD). Deposition of α-synuclein inclusions that spread from the gut to the substantia nigra through the vagus nerve has recently been speculated to be a pre-motor and early stage of PD. The aim of the study was to investigate whether constipation is associated with dopaminergic pathology on dopamine transporter (DAT) single-photon emission computed tomography in early drug-naïve patients with PD. Our hypothesis was that constipation is associated with other signs of pre-motor PD and is independent of DAT pathology. We then investigated for associations with motor and non-motor symptoms, and with cerebrospinal fluid biomarkers of PD pathology.

Using the Parkinson's Progression Markers Initiative database, we investigated the prevalence of constipation and the association between constipation and clinical features, striatal [¹²³ I]Ioflupane uptake and non-imaging (cerebrospinal fluid and serum) biomarkers. Constipation was evaluated using Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part I item 1.11.

One third (132/398) of de-novo patients with PD had constipation. Higher severity of constipation correlated with older age (r = 0.728, P < 0.001), higher MDS-UPDRS total score (r = 0.285, P < 0.001), worse postural instability (r = 0.190, P = 0.012), rapid eye movement sleep behaviour disorder (r = 0.228, P < 0.0001) and depression (r = 0.187, P = 0.024). No correlation was found with cerebrospinal fluid, serum and imaging markers of PD pathology.

Constipation was not associated with DAT pathology but with rapid eye movement sleep behaviour disorder and depression, which are speculated to be pre-motor symptoms of PD. This confirms the hypothesis that constipation may be a pre-motor sign of PD due to an impairment of non-dopaminergic pathways.

Objectives: To comprehensively review the scientific knowledge on the gut-brain axis. Methods: Various publications on the gut-brain axis, until 31 July 2017, were screened using the Medline, Google, and Cochrane Library databases. The search was performed using the following keywords: "gut-brain axis", "gut-microbiota-brain axis", "nutrition microbiome/microbiota", "enteric nervous system", "enteric glial cells/network", "gut-brain pathways", "microbiome immune system", "microbiome neuroendocrine system" and "intestinal/gut/enteric neuropeptides". Relevant articles were selected and reviewed. Results: Tremendous progress has been made in exploring the interactions between nutrients, the microbiome, and the intestinal, epithelium-enteric nervous, endocrine and immune systems and the brain. The basis of the gut-brain axis comprises of an array of multichannel sensing and trafficking pathways that are suggested to convey the enteric signals to the brain. These are mediated by neuroanatomy (represented by the vagal and spinal afferent neurons), the neuroendocrine-hypothalamic-pituitary-adrenal (HPA) axis (represented by the gut hormones), immune routes (represented by multiple cytokines), microbially-derived neurotransmitters, and finally the gate keepers of the intestinal and brain barriers. Their mutual and harmonious but intricate interaction is essential for human life and brain performance. However, a failure in the interaction leads to a number of inflammatory-, autoimmune-, neurodegenerative-, metabolic-, mood-, behavioral-, cognitive-, autism-spectrum-, stress- and pain-related disorders. The limited availability of information on the mechanisms, pathways and cause-and-effect relationships hinders us from translating and implementing the knowledge from the bench to the clinic. Implications: Further understanding of this intricate field might potentially shed light on novel preventive and therapeutic strategies to combat these disorders. Nutritional approaches, microbiome manipulations, enteric and brain barrier reinforcement and sensing and trafficking modulation might improve physical and mental health outcomes.

Chronic constipation is a common gastrointestinal disorder disproportionately affecting the elderly. Immobility, polypharmacy, and physiologic changes contribute to its increased prevalence in this population. Unidentified and undertreated constipation leads to a significant negative impact on quality of life and an increase in healthcare spending. Careful physical examination and exploration of the clinical history can unmask primary and secondary forms of constipation, guiding diagnostic and therapeutic considerations. Non-pharmacologic treatment options include bowel training and biofeedback as well as the addition of fiber. Laxatives are safe and can be used long term; thus, they remain the mainstay of therapy. Newer agents with specific physiologic targets have proven to be effective in adults with chronic constipation, but data is lacking for safety profile in the elderly. Consideration for surgery in medically refractory cases should be entertained, while use of neuromodulation is not ready for prime time. This is a review of the currently available treatment options for chronic constipation in adults and specifically tailored towards the elderly.

Clostridium difficile causes nosocomial/antibiotic-associated diarrhoea and pseudomembranous colitis. The major virulence factors are toxin A and toxin B (TcdB), which inactivate GTPases by monoglucosylation, leading to cytopathic (cytoskeleton alteration, cell rounding) and cytotoxic effects (cell-cycle arrest, apoptosis). C. difficile toxins breaching the intestinal epithelial barrier can act on underlying cells, enterocytes, colonocytes, and enteric neurons, as described in vitro and in vivo, but until now no data have been available on enteric glial cell (EGC) susceptibility. EGCs are crucial for regulating the enteric nervous system, gut homeostasis, the immune and inflammatory responses, and digestive and extradigestive diseases. Therefore, we evaluated the effects of C. difficile TcdB in EGCs. Rat-transformed EGCs were treated with TcdB at 0.1-10 ng/ml for 1.5-48 h, and several parameters were analysed. TcdB induces the following in EGCs: (1) early cell rounding with Rac1 glucosylation; (2) early G2/M cell-cycle arrest by cyclin B1/Cdc2 complex inactivation caused by p27 upregulation, the downregulation of cyclin B1 and Cdc2 phosphorylated at Thr161 and Tyr15; and (3) apoptosis by a caspase-dependent but mitochondria-independent pathway. Most importantly, the stimulation of EGCs with TNF-α plus IFN-γ before, concomitantly or after TcdB treatment strongly increased TcdB-induced apoptosis. Furthermore, EGCs that survived the cytotoxic effect of TcdB did not recover completely and showed not only persistent Rac1 glucosylation, cell-cycle arrest and low apoptosis but also increased production of glial cell-derived neurotrophic factor, suggesting self-rescuing mechanisms. In conclusion, the high susceptibility of EGCs to TcdB in vitro, the increased sensitivity to inflammatory cytokines related to apoptosis and the persistence of altered functions in surviving cells suggest an important in vivo role of EGCs in the pathogenesis of C. difficile infection.

Enteric glial cells (EGCs) are components of the intestinal epithelial barrier essential for regulating the enteric nervous system. Clostridium difficile is the most common cause of antibiotic-associated colitis, toxin B (TcdB) being the major virulence factor, due to its ability to breach the intestinal epithelial barrier and to act on other cell types. Here we investigated TcdB effects on EGCs and the activated molecular mechanisms. Already at 2 hours, TcdB triggered ROS formation originating from NADPH-oxidase, as demonstrated by their reduction in the presence of the NADPH-oxidase inhibitor ML171. Although EGCs mitochondria support almost completely the cellular ATP need, TcdB exerted weak effects on EGCs in terms of ATP and mitochondrial functionality, mitochondrial ROS production occurring as a late event. ROS activated the JNK signalling and overexpression of the proapoptotic Bim not followed by cytochrome c or AIF release to activate the downstream apoptotic cascade. EGCs underwent DNA fragmentation through activation of the ROS/JNK/caspase-3 axis, evidenced by the ability of ML171, N-acetylcysteine, and the JNK inhibitor SP600125 to inhibit caspase-3 or to contrast apoptosis. Therefore, TcdB aggressiveness towards EGCs is mainly restricted to the cytosolic compartment, which represents a peculiar feature, since TcdB primarily influences mitochondria in other cellular types.

The postnatal period is crucial for the development of gastrointestinal (GI) functions. The enteric nervous system is a key regulator of GI functions, and increasing evidences indicate that 1) postnatal maturation of enteric neurons affect the development of GI functions, and 2) microbiota-derived short-chain fatty acids can be involved in this maturation. Although enteric glial cells (EGC) are central regulators of GI functions, the postnatal evolution of their phenotype remains poorly defined. We thus characterized the postnatal evolution of EGC phenotype in the colon of rat pups and studied the effect of short-chain fatty acids on their maturation. We showed an increased expression of the glial markers GFAP and S100β during the first postnatal week. As demonstrated by immunohistochemistry, a structured myenteric glial network was observed at 36 days in the rat colons. Butyrate inhibited EGC proliferation in vivo and in vitro but had no effect on glial marker expression. These results indicate that the EGC myenteric network continues to develop after birth, and luminal factors such as butyrate endogenously produced in the colon may affect this development.

Constipation is a frequently reported bowel symptom in the elderly with considerable impact on quality of life and health expenses. Disease-related morbidity and even mortality have been reported in the affected frail elderly. Although constipation is not a physiologic consequence of normal aging, decreased mobility, medications, underlying diseases, and rectal sensory-motor dysfunction may all contribute to its increased prevalence in older adults. In the elderly there is usually more than one etiologic mechanism, requiring a multifactorial treatment approach. The majority of patients would respond to diet and lifestyle modifications reinforced by bowel training measures. In those not responding to conservative treatment, the approach needs to be tailored addressing all comorbid conditions. In the adult population, the management of constipation continues to evolve as well as the understanding of its complex etiology. However, the constipated elderly have been left behind while gastroenterology consultations for this common conditions are at a rise for the worldwide age increment. Aim of this review is to provide an update on epidemiology, quality of life burden, etiology, diagnosis, current approaches and limitations in the management of constipation in the older ones to ease the gastroenterologists' clinic workload.

Enteroglial cells (EGCs) play critical roles in human health and disease, however, EGC-dependent neuropathies also affect commercially important animal species. Due to the lack of data on the distribution and phenotypic characterization of the EGCs throughout the bovine gastrointestinal tract, in this study the topographic localization of EGCs in the jejunum of healthy cattle was investigated by immunofluorescence using the glial specific marker glial fibrillary acidic protein (GFAP) and the panneuronal marker PGP 9.5. This analysis was conducted on both cryosections and whole mount preparations including the myenteric and the submucous plexuses of the bovine jejunum. The results obtained showed the presence of a large subpopulation of GFAP-expressing EGCs in the main plexuses and within the muscle layers, whereas only few GFAP-positive glial processes were found within the deeper layer of the mucosa, and they never reached the mucosal epithelium. Three different EGC subtypes, namely I, III and IV types were recognized in the examined tract of the bovine intestine. Overall, our results provide the basis for future investigations aimed at elucidating the functional role of the GFAP-containing EGCs which is crucial for a better understanding of the physio-pathology of the bovine intestine.

The psycho-neuroendocrine-immune approach relies on the concept of considering diseases from a holistic point of view: the various components (psyche, nervous system, endocrine system, and immune system) control the diseased organ/apparatus and in turn are influenced by a feedback mechanism. In this article, we will consider the psycho-neuroendocrine-immune approach to coloproctological disorders, by providing clinical cases and discussing them in light of this approach.

In recent years, the improvement of technology and the increase in knowledge have shifted several strongly held paradigms. This is particularly true in gastroenterology, and specifically in the field of the so-called "functional" or "idiopathic" disease, where conditions thought for decades to be based mainly on alterations of visceral perception or aberrant psychosomatic mechanisms have, in fact, be reconducted to an organic basis (or, at the very least, have shown one or more demonstrable abnormalities). This is particularly true, for instance, for irritable bowel syndrome, the prototype entity of "functional" gastrointestinal disorders, where low-grade inflammation of both mucosa and myenteric plexus has been repeatedly demonstrated. Thus, researchers have also investigated other functional/idiopathic gastrointestinal disorders, and found that some organic ground is present, such as abnormal neurotransmission and myenteric plexitis in esophageal achalasia and mucosal immune activation and mild eosinophilia in functional dyspepsia. Here we show evidence, based on our own and other authors' work, that chronic constipation has several abnormalities reconductable to alterations in the enteric nervous system, abnormalities mainly characterized by a constant decrease of enteric glial cells and interstitial cells of Cajal (and, sometimes, of enteric neurons). Thus, we feel that (at least some forms of) chronic constipation should no more be considered as a functional/idiopathic gastrointestinal disorder, but instead as a true enteric neuropathic abnormality.

Chronic constipation is a frequently complained condition in clinical practice and may be primary (idiopathic) or due to secondary causes. The definition of the various forms of constipation is presently made according to the Rome III criteria, which recently incorporated also specific diagnostic algorithms. The diagnosis of constipation relies on the patient's history, including use of drugs, physical examination, and specific investigations (transit time, anorectal manometry, balloon expulsion test, defecography). These will often be useful to start a targeted therapeutic schedule that may include fibres, laxatives, biofeedback training and, in extreme cases, a surgical approach. This review will analyse the clinical and diagnostic aspects of chronic constipation in adult patients, with emphasis on recent therapeutic approaches.

Chronic constipation is a commonly encountered symptom in everyday clinical practice, and numerous drugs are available for its medical treatment. However, there are several misconceptions that still often limit an effective approach, as well as the fact that it is older but effective treatments are sometimes neglected in favor of more recent, but not necessarily more effective, treatments. The actual knowledge on the efficacy and safety of currently available laxative treatment for chronic constipation, as shown by the review on which this editorial comments, clearly demonstrates that constipation may be effectively treated in most cases. Those caring for constipated patients, however, must be confident with use (and misuse) of medical treatment, to avoid lack of efficacy and onset of side effects leading to drug withdrawal. As for many other pathological issues, understanding the pathophysiological grounds of the condition to face greatly simplifies and accurately individuates the problem, to target the problem and help in reaching the therapeutic goal.

In diabetes mellitus (DM), hyperglycemia promotes changes in biochemical mechanisms that induce oxidative stress. Oxidative stress has been closely linked to adverse consequences that affect the function of the gastrointestinal tract caused by injuries to the enteric nervous system (ENS) that in turn cause neurodegeneration and enteric glial loss. Therapeutic approaches have shown that diet supplementation with antioxidants, such as quercetin, reduce oxidative stress.

This work sought to evaluate neurons and enteric glial cells in the myenteric and submucosal plexuses of the duodenum in diabetic rats supplemented with quercetin.

The duodenum of 24 rats, including a control group (C), control quercetin supplementation group (CQ), diabetic group (D), and diabetic quercetin supplementation group (DQ), were used to investigate whole mounts of muscular and submucosal layers subjected to immunohistochemistry to detect vasoactive intestinal peptide in the myenteric layer and double-staining for HuC-D/neuronal nitric oxide synthase (nNOS) and HuC-D/S100.

A reduction of the general neuronal population (HuC/D) was found in the myenteric and submucosal plexuses (p < 0.001) in the D and DQ groups. The nitrergic subpopulation (nNOS) decreased only in the myenteric plexus (p < 0.001), and glial cells decreased in both plexuses (p < 0.001) in the D and DQ groups. In diabetic rats, quercetin supplementation reduced neuronal and glial loss. Diabetes promoted an increase in the cell body area of both the general and nitrergic populations. Quercetin supplementation only prevented neuronal hypertrophy in the general population.

Supplementation with quercetin eased the damage caused by diabetes, promoting a neuroprotective effect and reducing enteric glial loss in the duodenum.

Although diverticular disease of the colon (diverticulosis) is a frequent finding in Western countries, its pathophysiologic grounds are still only partially understood. Traditionally considered as an age-related condition, colonic diverticulosis is probably the final result of several factors concurring together to determine the anatomo-functional abnormalities eventually causing outpouching of the viscus' mucosa. Among these factors, a relevant role seems to be played by an abnormal neuromuscular function of the large bowel, as shown by abnormal myoelectrical and motor function repeatedly described in these patients, as well as by altered visceral perception. These anomalies might be related to the recent demonstration of derangement of enteric innervation (especially involving interstitial cells of Cajal and enteric glial cells), mucosal neuropeptides, and mucosal inflammation. The latter may have a role of paramount importance in the development of visceral hypersensitivity, responsible for abdominal pain in a subset of patients.

Slow-transit constipation is a relatively frequent subtype of constipation, often refractory to medical treatment. Clinical information is usually obtained in patients during laxative withdrawal; thus, data on the effect of laxatives on their daily symptoms are lacking. The evaluated article reports on the effects of laxatives on symptoms (stool frequency, stool form, straining at stool, pain and bloating) and on laxative use by means of a daily stool questionnaire. Most patients used laxatives on an intermittent basis, and a minority also used associated enemas. Use of laxatives yielded an almost average normal daily number of evacuations in this group, with only a minority having less than three bowel movements per week. The days in which patients used laxatives yielded significantly more frequent and loose stools compared with those without laxatives. Thus, the use of laxatives seems to influence the clinical aspects of patients with slow-transit constipation, and this should be considered when evaluating these participants.

The pathophysiological basis of obstructed defecation (OD) is still incompletely understood. In particular, few or no data are available concerning the enteric nervous system (ENS) in this condition. We investigated ENS abnormalities in patients with OD, undergoing surgery, together with the presence of estrogen (α and β) and progesterone receptors, and compare the results with those obtained in controls.

Full-thickness rectal samples were obtained from 17 patients undergoing stapled transanal rectal resection for OD associated with rectal intussusception. Samples were analyzed by immunohistochemistry for enteric neurons, enteric glial cells, interstitial cells of Cajal (ICC), and for estrogen and progesterone receptors. Data were compared with those obtained in 10 controls.

No differences between patients and controls were found for enteric neurons, whereas (compared with controls) OD patients displayed a significant decrease of enteric glial cells in both the submucous (P = 0.0006) and the myenteric (P < 0.0001) plexus. ICC were significantly increased in patients in the submucosal surface (P < 0.0001) and the myenteric area (P < 0.0001). Concerning estroprogestinic receptors, both were present on ICC in patients and controls. Estrogen receptors α and progesterone receptors were absent on enteric neurons and enteric glial cells in patients and controls, whereas estrogen receptors β were present in all controls and in 69% of patients' enteric neurons (P = 0.18) and in 12% of patients' glial cells (P = 0.0001).

Patients with OD associated to rectal intussusception display abnormalities of the ENS and of estrogen receptors β.

Mast cells are involved in visceral hypersensitivity and motor activity of the gastrointestinal tract. However, there is almost no information concerning mast cells in constipated patients.

The purpose of this study was to investigate mast cells distribution in all colonic layers in controls and severely constipated patients with obstructed defecation.

Full-thickness specimens from colons of patients undergoing surgery for obstructed defecation due to refractoriness to other therapeutic interventions (n = 11), compared to controls, were obtained and the number of mast cells (evaluated by specific monoclonal antibodies) were counted in the whole viscus and in the various colonic segments (cecum, ascending, transverse, descending, and sigmoid).

Compared to controls, constipated patients had significantly higher numbers of mast cells, both as an overall number and in single colonic segments. This increase was especially evident in the mucosa and submucosa. Mast cells were homogeneously represented in the various segment of the large bowel, in both controls and patients. Degranulated mast cells were found to be close to enteric glial cells and glial filaments.

Colonic mast cells are increased in obstructed defecation patients. This might represent a vicariating mechanism to the impaired colonic propulsive activity of these patients.

Chronic constipation requiring surgical ablation for intractability is often a frustrating condition from the pathologist's point of view. In fact, limiting the histological examination to only hematoxylin-eosin staining usually yields only the information that there are no abnormalities. By employing some simple and widely available immunohistochemical methods, discussed in this review, it is possible to gather data that may help in explaining the pathophysiological basis of constipation in these patients.

CIPO is the very “tip of the iceberg” of functional gastrointestinal disorders, being a rare and frequently misdiagnosed condition characterized by an overall poor outcome. Diagnosis should be based on clinical features, natural history and radiologic findings. There is no cure for CIPO and management strategies include a wide array of nutritional, pharmacologic, and surgical options which are directed to minimize malnutrition, promote gut motility and reduce complications of stasis (ie, bacterial overgrowth). Pain may become so severe to necessitate major analgesic drugs. Underlying causes of secondary CIPO should be thoroughly investigated and, if detected, treated accordingly. Surgery should be indicated only in a highly selected, well characterized subset of patients, while isolated intestinal or multivisceral transplantation is a rescue therapy only in those patients with intestinal failure unsuitable for or unable to continue with TPN/HPN. Future perspectives in CIPO will be directed toward an accurate genomic/proteomic phenotying of these rare, challenging patients. Unveiling causative mechanisms of neuro-ICC-muscular abnormalities will pave the way for targeted therapeutic options for patients with CIPO.