Over the past six decades, liver transplantation (LT) has evolved from an experimental procedure into a standardized and life-saving intervention, reshaping the landscape of organ transplantation. Driven by pioneering breakthroughs, technological advancements, and a deepened understanding of immunology, LT has seen remarkable progress. Some of the most notable breakthroughs in the field include advances in immunosuppression, a revised model for end-stage liver disease, and artificial intelligence (AI)-integrated imaging modalities serving diagnostic and therapeutic roles in LT, paired with ever-evolving technological advances. Additionally, the refinement of transplantation procedures, resulting in the introduction of alternative transplantation methods, such as living donor LT, split LT, and the use of marginal grafts, has addressed the challenge of organ shortage. Moreover, precision medicine, guiding personalized immunosuppressive strategies, has significantly improved patient and graft survival rates while addressing emergent issues, such as short-term complications and early allograft dysfunction, leading to a more refined strategy and enhanced post-operative recovery. Looking ahead, ongoing research explores regenerative medicine, diagnostic tools, and AI to optimize organ allocation and post-transplantation car. In summary, the past six decades have marked a transformative journey in LT with a commitment to advancing science, medicine, and patient-centered care, offering hope and extending life to individuals worldwide.

Cirrhosis is a major cause of morbidity and mortality; however, there are no approved therapies except orthotopic liver transplantation. Preclinical studies showed that bone-marrow-derived macrophage injections reduce inflammation, resolve fibrosis and stimulate liver regeneration. In a multicenter, open-label, parallel-group, phase 2 randomized controlled trial ( ISRCTN10368050 ) in n = 51 adult patients with compensated cirrhosis and Model for End-Stage Liver Disease (MELD) score ≥10 and ≤17, we evaluated the efficacy of autologous monocyte-derived macrophage therapy (n = 27) compared to standard medical care (n = 24). The primary endpoint was the difference in baseline to day 90 change in MELD score (ΔMELD) between treatment and control groups (ΔΔMELD). Secondary endpoints included adverse clinical outcomes, non-invasive fibrosis biomarkers and health-related quality of life (HRQoL) at 90 d, 180 d and 360 d. The ΔΔMELD between day 0 and day 90 in the treatment group compared to controls was -0.87 (95% confidence interval: -1.79, 0.0; P = 0.06); therefore, the primary endpoint was not met. During 360-d follow-up, five of 24 participants in the control group developed a total of 10 severe adverse events, four of which were liver related, and three deaths (two liver related), whereas no liver-related severe adverse events or deaths occurred in the treatment group. Although no differences were observed in biomarkers or HRQoL, exploratory analysis showed anti-inflammatory serum cytokine profiles after macrophage infusion. This study reinforces the safety and potential efficacy of macrophage therapy in cirrhosis, supporting further investigation.

Cirrhosis is a disease with poor prognosis that requires the development of a novel therapeutic approach alternative to liver transplantation. In this study, we focused on the placenta and aimed to clarify the effects of human placental extract (HPE) on cirrhosis.

A mouse model of carbon tetrachloride-induced cirrhosis was used to evaluate the effect of HPE administration subcutaneously and compared with the control group (n = 8 for each group). In vitro and in vivo, real time-PCR and immunostaining were performed for HPE mechanistic analysis. Spatial transcriptomics was also performed for detailed analysis of the effect of HPE on cirrhosis.

HPE administration improved serum ALT levels compared to control mice. Furthermore, there was a decrease in the number of senescent cells in the liver and the mRNA levels of secrete senescence-associated secretory phenotype factors and Cdkn2a (p16). In vitro, HPE induced macrophage polarization to the anti-inflammatory M2 phenotype. Spatial transcriptomics was also performed to analyze the underlying anti-inflammatory mechanism. The results showed that HPE strongly polarized macrophages to the M2 phenotype, especially in macrophage-rich regions in the liver. Gene expression pathway analysis using spatial transcriptomics also revealed the possibility of improving senescent cell-derived inflammation via mitochondrial function.

HPE improves serum ALT levels via anti-inflammatory mechanisms in macrophages and senescent cells. HPE serves as a novel agent for cirrhosis treatment.

For the treatment of liver fibrosis, several novel cell therapies have been proposed. Autologous macrophage therapy has been reported as one of the promising treatments. So far, most studies have used colony-stimulating factor 1 (CSF-1) to induce the differentiation of macrophage progenitor cells. The receptor for CSF-1, CSF-1R possesses another ligand, interleukin 34. However, the therapeutic capacity for liver fibrosis by interleukin 34-induced macrophages has not been evaluated.

We have employed acute (bile duct ligation) and chronic (administration of carbon tetrachloride or thioacetamide) liver fibrosis models. Using these models, we evaluated the therapeutic capacity of macrophages induced by interleukin 34-based conditions. In most experiments, interleukin 4 was also added to the differentiation process to induce alternative-activated macrophages. As a mechanism analysis, we have examined liver inflammation and damage, the status of stellate cells, and the immunosuppressive capacity of the macrophages. Human macrophages were differentiated from CD14+ monocytes and analyzed.

In both acute and chronic liver damage experiments, interleukin 34-induced macrophages significantly ameliorated liver fibrosis. The addition of interleukin 4 to the differentiation process resulted in an increase of obtained macrophages and a bias to alternative activated macrophages (so-called M2). The alternative activated macrophages (M2-type) showed a reproducible therapeutic effect of liver fibrosis with a suppression of parameters of liver inflammation and damage, stellate cells, and T cell activation. Similar macrophages could be differentiated from human CD14+ monocytes in the presence of interleukin 34 plus interleukin 4, and a therapeutic effect was observed using a humanized mouse model.

Interleukin 34-induced macrophages, particularly when additionally stimulated with interleukin 4, significantly ameliorated the liver fibrosis.

Acute liver failure is a rapidly progressing, life-threatening condition most commonly caused by an overdose of acetaminophen (paracetamol). The antidote, N-acetylcysteine (NAC), has limited efficacy when liver injury is established. If acute liver damage is severe, liver failure can rapidly develop with associated high mortality rates. We have previously demonstrated that alternatively, activated macrophages are a potential therapeutic option to reverse acute liver injury in pre-clinical models. In this paper, we present data using cryopreserved human alternatively activated macrophages (hAAMs)-which represent a potential, rapidly available treatment suitable for use in the acute setting. In a mouse model of APAP-induced injury, peripherally injected cryopreserved hAAMs reduced liver necrosis, modulated inflammatory responses, and enhanced liver regeneration. hAAMs were effective even when administered after the therapeutic window for NAC. This cell therapy approach represents a potential treatment for APAP overdose when NAC is ineffective because liver injury is established.

Acute liver injury (ALI) has a clear requirement for novel therapies. One emerging option is the use of alternatively activated macrophages (AAMs); a distinct subtype of macrophage with a role in liver injury control and repair. In this comprehensive review, we provide an overview of the current limited options for ALI, and the potential advantages offered by AAMs. We describe the evidence supporting their use from in vitro studies, pre-clinical animal studies, and human clinical trials. We suggest why the first evidence for the clinical use of AAMs is likely to be found in acetaminophen toxicity, and discuss the specific evidence for AAM use in this population, as well as potential applications for AAMs in other patient populations. The key domains by which the performance of AAMs for the treatment of ALI will be assessed are identified, and remaining challenges to the successful delivery of AAMs to clinic are explored.

As the final stage of disease-related tissue injury and repair, fibrosis is characterized by excessive accumulation of the extracellular matrix. Unrestricted accumulation of stromal cells and matrix during fibrosis impairs the structure and function of organs, ultimately leading to organ failure. The major etiology of fibrosis is an injury caused by genetic heterogeneity, trauma, virus infection, alcohol, mechanical stimuli, and drug. Persistent abnormal activation of "quiescent" fibroblasts that interact with or do not interact with the immune system via complicated signaling cascades, in which parenchymal cells are also triggered, is identified as the main mechanism involved in the initiation and progression of fibrosis. Although the mechanisms of fibrosis are still largely unknown, multiple therapeutic strategies targeting identified molecular mechanisms have greatly attenuated fibrotic lesions in clinical trials. In this review, the organ-specific molecular mechanisms of fibrosis is systematically summarized, including cardiac fibrosis, hepatic fibrosis, renal fibrosis, and pulmonary fibrosis. Some important signaling pathways associated with fibrosis are also introduced. Finally, the current antifibrotic strategies based on therapeutic targets and clinical trials are discussed. A comprehensive interpretation of the current mechanisms and therapeutic strategies targeting fibrosis will provide the fundamental theoretical basis not only for fibrosis but also for the development of antifibrotic therapies.

Ginkgo biloba extract is reported to have therapeutic effects on aging-related disorders. However, the specific component responsible for this biological function and its mechanism of action remain largely unknown. This study finds that Ginkgetin, an active ingredient of Ginkgo biloba extract, can alleviate cellular senescence and improve pathologies in multiple tissues of aging mice. To reveal the molecular mechanism of Ginkgetin's anti-aging effect, a graph convolutional network-based drug "on-target" pathway prediction algorithm for prediction is employed. The results indicate that the cGAS-STING pathway may be a potential target for Ginkgetin. Subsequent cell biological and biophysical data confirmed that Ginkgetin directly binds to the carboxy-terminal domain of STING protein, thereby inhibiting STING activation and signal transduction. Furthermore, in vivo pharmacodynamic data showed that Ginkgetin effectively alleviates systemic inflammation in Trex1-/- mice and inhibits the abnormally activated STING signaling in aging mouse model. In summary, this study, utilizing an artificial intelligence algorithm combined with pharmacological methods, confirms STING serves as a critical target for Ginkgetin in alleviating inflammation and senescence. Importantly, this study elucidates the specific component and molecular mechanism underlying the anti-aging effect of Ginkgo biloba extract, providing a robust theoretical basis for its therapeutic use.

Interleukin-4 activated human macrophages [M(IL4)s] promote epithelial wound healing and exert an anticolitic effect in a murine model. Blood monocyte-derived M(IL4)s from healthy donors and individuals with Crohn's disease had increased mRNA expression of the calcitonin gene-related peptide (CGRP) receptor chain, receptor activity modifying protein-1 (RAMP1), raising the issue of neural modulation of the M(IL4)s reparative function. Thus, human M(IL4)s were treated with CGRP and the cells' phagocytotic, epithelial wound repair and anticolitic functions were assessed. Initial studies confirmed upregulation of expression of the CGRP receptor, which was localized to the cell surface and was functional as determined by CGRP-evoked increases in cAMP. M(IL4,CGRP)s had increased mannose receptor (CD206) and FcγRIIa (CD32a) mRNA expression, a subtle, but significant, increase in phagocytosis and decreased chemokine production following the exposure to Escherichia coli. When delivered systemically (106 cells IP) to oxazolone-treated rag1-/- mice, M(IL4,CGRP) had an anticolitic effect superior to M(IL4)s from the same blood donor. Conditioned medium (CM) from M(IL4,CGRP) had increased amounts of transforming growth factor (TGF)-β and increased wound-healing capacity compared with matched M(IL4)-CM in the human CaCo2 epithelial cell line in-vitro wounding assay. Moreover, M(IL4,CGRP)s displayed increased cyclooxygenase (COX)-1 and prostaglandin D2 (PGD2), and CM from M(IL4,CGRP)s treated with indomethacin or SC-560 to inhibit COX-1 activity failed to promote repair of wounded CaCo2 cell monolayers. These data confirm the human M(IL4)s' anticolitic effect that was enhanced by CGRP and may be partially dependent on macrophage COX-1/PGD2 activity. Thus, input from neurone-derived molecules is a local modifier capable of boosting the anticolitic effect of autologous M(IL4) transfer.NEW & NOTEWORTHY A novel pathway is identified whereby interleukin-4-educated human macrophages [M(IL4)s] exposed to calcitonin gene-related peptide (CGRP) reduce oxazolone-induced colitis and promote epithelial wound healing in vitro through COX1-dependent signaling. Support is provided for the concept of macrophage transfer to treat enteric inflammation where neuroimmune interaction, in this case CGRP neuropeptide, produced under inflammatory conditions will reinforce the anticolitic and wound repair capacity of M(IL4) autologous-based therapy for IBD treatment.

Liver fibrosis develops in response to chronic liver injury and is characterized by a sustained inflammatory response that leads to excessive collagen deposition by myofibroblasts. The fibrogenic response is governed by the release of inflammatory mediators from innate, adaptive, and innate-like lymphoid cells and from nonprofessional immune cells (i.e., epithelial cells, hepatic myofibroblasts, and liver sinusoidal endothelial cells). Upon removal of the underlying cause, liver fibrosis can resolve via activation of specific immune cell subsets. Despite major advances in the understanding of fibrosis pathogenesis, there is still no approved antifibrotic therapy. This review summarizes our current knowledge of the immune cell landscape and the inflammatory mechanisms underlying liver fibrosis progression and regression. We discuss how reprogramming immune cell phenotype, in particular through targeting selective inflammatory pathways or modulating cell-intrinsic metabolism, may be translated into antifibrogenic therapies.

Macrophages, the predominant immune cells in the liver, are essential for maintaining hepatic homeostasis and responding to liver injury caused by external stressors. The hepatic macrophage population is highly heterogeneous and plastic, mainly comprised of hepatic resident kuffer cells (KCs), monocyte-derived macrophages (MoMφs), lipid-associated macrophages (LAMs), and liver capsular macrophages (LCMs). KCs, a population of resident macrophages, are localized in the liver and can self-renew through in situ proliferation. However, MoMφs in the liver are recruited from the periphery circulation. LAMs are a self-renewing subgroup of liver macrophages near the bile duct. While LCMs are located in the liver capsule and derived from peripheral monocytes. LAMs and LCMs are also involved in liver damage induced by various factors. Hepatic macrophages exhibit distinct phenotypes and functions depending on the specific microenvironment in the liver. KCs are critical for initiating inflammatory responses after sensing tissue damage, while the MoMφs infiltrated in the liver are implicated in both the progression and resolution of chronic hepatic inflammation and fibrosis. The regulatory function of liver macrophages in hepatic fibrosis has attracted significant interest in current research. Numerous literatures have documented that the MoMφs in the liver have a dual impact on the progression and resolution of liver fibrosis. The MoMφs in the liver can be categorized into two subtypes based on their Ly-6C expression level: inflammatory macrophages with high Ly-6C expression (referred to as Ly-6Chi subgroup macrophages) and reparative macrophages with low Ly-6C expression (referred to as Ly-6Clo subgroup macrophages). Ly-6Chi subgroup macrophages are conducive to the occurrence and progression of liver fibrosis, while Ly-6Clo subgroup macrophages are associated with the degradation of extracellular matrix (ECM) and regression of liver fibrosis. Given this, liver macrophages play a pivotal role in the occurrence, progression, and regression of liver fibrosis. Based on these studies, treatment therapies targeting liver macrophages are also being studied gradually. This review aims to summarize researches on the composition and origin of liver macrophages, the macrophage heterogeneity in the progression and regression of liver fibrosis, and anti-fibrosis therapeutic strategies targeting macrophages in the liver.

The intestine and liver share a unique regenerative property that sets them apart from other mammalian visceral organs. The intestinal epithelium exhibits rapid renewal, making it one of the fastest renewing tissues in humans. Under physiological conditions, intestinal stem cells within each intestinal crypt continuously differentiate into the different types of intestinal epithelial cells to maintain intestinal homeostasis. However, when exposed to tissue damage or stressful conditions such as inflammation, intestinal epithelial cells in the gastrointestinal tract exhibit plasticity, allowing fully differentiated cells to regain their stem cell properties. Likewise, hepatic epithelial cells possess a remarkable regenerative capacity to restore lost liver mass through proliferation-mediated liver regeneration. When the proliferation-mediated regenerative capacity is impaired, hepatocytes and biliary epithelial cells (BECs) can undergo plasticity-mediated regeneration and replenish each other. The transition of mammalian liver progenitor cells to hepatocytes/BECs can be observed under tightly controlled experimental conditions such as severe hepatocyte injury accompanied by the loss of regenerative capacity. In this review, we will discuss the mechanism by which cellular plasticity contributes to the regeneration process and the potential therapeutic implications of understanding and harnessing cellular plasticity in the gut and liver.

Under the rapid advancement of chimeric antigen receptor T cell (CAR-T) technology, CAR-macrophages (CAR-Ms) are also being developed currently in the pre-clinical stage and have been shown to inhibit tumor growth in several mouse tumor models. Fibroblast activation protein (FAP) is a type II transmembrane serine protease, which is expressed in stromal fibroblasts of over 90 % of common human epithelial cancers and is upregulated in fibrotic diseases of the liver, lung and colon, etc. In this study, we firstly constructed FAP-CAR macrophages to target FAP+ cells through in vitro phagocytosis assays. In subsequent in vivo assays, we discovered that FAP-CAR-ΔZETA bone marrow-derived macrophages (BMDMs) rather than FAP-CAR BMDMs, exhibited a pronounced anti-tumor effect in mouse subcutaneous MC38 colon cancer model. In addition, FAP-CAR and FAP-CAR-ΔZETA BMDMs therapy could effectively improve CCl4-induced liver fibrosis in mice. Collectively, CAR-Ms targeting FAP demonstrated great therapeutic potential in cancer and liver fibrosis therapy.

The immunomodulatory oligodeoxynucleotide (ODN) IMT504 might harbor antifibrotic properties within the liver.

Fibrosis models were induced in mice through thioacetamide (TAA) administration and bile-duct ligation. Cre-loxP mice were utilized to identify GLAST + Wnt1 + bone marrow stromal progenitors (BMSPs) and to examine their contribution with cells in the liver. In vivo and in vitro assays; flow-cytometry, immunohistochemistry, and qPCR were conducted.

IMT504 demonstrated significant inhibition of liver fibrogenesis progression and reversal of established fibrosis. Early responses to IMT504 involved the suppression of profibrogenic and proinflammatory markers, coupled with an augmentation of hepatocyte proliferation. Additionally, this ODN stimulated the proliferation and mobilization of GLAST + Wnt1 + BMSPs, likely amplifying their contribution with endothelial- and hepatocytes-like cells. Moreover, IMT504 significantly modulated the expression levels of Wnt ligands and signaling pathway/target genes specifically within GLAST + Wnt1 + BMSPs, with minimal impact on other BMSPs. Intriguingly, both IMT504 and conditioned media from IMT504-pre-treated GLAST + Wnt1 + BMSPs shifted the phenotype of fibrotic macrophages, hepatic stellate cells, and hepatocytes, consistent with the potent antifibrotic effects observed.

In summary, our findings identify IMT504 as a promising candidate molecule with potent antifibrotic properties, operating through both direct and indirect mechanisms, including the activation of GLAST + Wnt1 + BMSPs.

The potential of extracellular vesicles (EVs) isolated from mesenchymal stromal cells in guiding macrophages toward anti-inflammatory immunophenotypes, has been reported in several studies. In our study, we provided experimental evidence of a distinctive effect played by Wharton Jelly mesenchymal stromal cell-derived EVs (WJ-EVs) on human macrophages. We particularly analyzed their anti-inflammatory effects on macrophages by evaluating their interactions with stellate cells, and their protective role in liver fibrosis. A three-step gradient method was used to isolate monocytes from umbilical cord blood (UCB). Two subpopulations of WJ-EVs were isolated by high-speed (20,000 g) and differential ultracentrifugation (110,000 g). Further to their characterization, they were designated as EV20K and EV110K and incubated at different concentrations with UCB-derived monocytes for 7 days. Their anti-fibrotic effect was assessed by studying the differentiation and functional levels of generated macrophages and their potential to modulate the survival and activity of LX2 stellate cells. The EV20K triggers the polarization of UCB-derived monocytes towards a peculiar M2-like functional phenotype more effectively than the M-CSF positive control. The EV20K treated macrophages were characterized by a higher expression of scavenger receptors, increased phagocytic capacity and production level of interleukin-10 and transforming growth factor-β. Conditioned medium from those polarized macrophages attenuated the proliferation, contractility and activation of LX2 stellate cells. Our data show that EV20K derived from WJ-MSCs induces activated macrophages to suppress immune responses and potentially play a protective role in the pathogenesis of liver fibrosis by directly inhibiting HSC's activation.

Bone marrow stem cells (BM-SCs) and their progeny play a central role in tissue repair and regeneration. In patients with chronic liver failure, bone marrow (BM) reserve is severally compromised and they showed marked defects in the resolution of injury and infection, leading to liver failure and the onset of decompensation. Whether BM failure is the cause or consequence of liver failure during cirrhosis is not known. In this study, we aimed to determine the underlying relationship between BM failure and regeneration failure in cirrhosis.

C57Bl/6(J) mice were used to develop chronic liver injury through intra-peritoneal administration of carbon tetrachloride (CCl4) for 15 weeks (0.1-0.5 ml/kg). Animals were sacrificed to study the transition of cirrhosis and BM defects. To restore the BM-SC reserve; healthy BM cells were infused via intra-BM infusion and assessed for changes in liver injury, regeneration, and BM-SC reserve.

Using a CCl4-induced animal - model of cirrhosis, we showed the loss of BM-SCs reserve occurred before regeneration failure and the onset of non-acute decompensation. Intra-BM infusion of healthy BM cells induced the repopulation of native hematopoietic stem cells (HSCs) in cirrhotic BM. Restoring BM-HSCs reserve augments liver macrophage-mediated clearance of infection and inflammation dampens neutrophil-mediated inflammation, accelerates fibrosis regression, enhances hepatocyte proliferation, and delays the onset of non-acute decompensation.

These findings suggest that loss of BM-HSCs reserve underlies the compromised innate immune function of the liver, drives regeneration failure, and the onset of non-acute decompensation. We further provide the proof-of-concept that rejuvenating BM-HSC reserve can serve as a potential therapeutic approach for preventing regeneration failure and transition to decompensated cirrhosis.

Chimeric antigen receptor-T cells have spearheaded the field of adoptive cell therapy and have shown remarkable results in treating hematological neoplasia. Because of the different biology of solid tumors compared to hematological tumors, response rates of CAR-T cells could not be transferred to solid entities yet. CAR engineering has added co-stimulatory domains, transgenic cytokines and switch receptors to improve performance and persistence in a hostile tumor microenvironment, but because of the inherent cell type limitations of CAR-T cells, including HLA incompatibility, toxicities (cytokine release syndrome, neurotoxicity) and high costs due to the logistically challenging preparation process for autologous cells, the use of alternative immune cells is gaining traction. NK cells and γδ T cells that do not need HLA compatibility or macrophages and dendritic cells with additional properties such as phagocytosis or antigen presentation are increasingly seen as cellular vehicles with potential for application. As these cells possess distinct properties, clinicians and researchers need a thorough understanding of their peculiarities and commonalities. This review will compare these different cell types and their specific modes of action seen upon CAR activation.

At present, wound dressings in clinical applications are primarily used for superficial skin wounds. However, these dressings have significant limitations, including poor biocompatibility and limited ability to promote wound healing. To address the issue, this study used aldehyde polyethylene glycol as the cross-linking agent to design a carboxymethyl chitosan-methacrylic acid gelatin hydrogel with enhanced biocompatibility, which can promote wound healing and angiogenesis. The CSDG hydrogel exhibits acid sensitivity, with a swelling ratio of up to 300%. Additionally, it exhibited excellent resistance to external stress, withstanding pressures of up to 160 kPa and self-deformation of 80%. Compared to commercially available chitosan wound gels, the CSDG hydrogel demonstrates excellent biocompatibility, antibacterial properties, and hemostatic ability. Bothin vitroandin vivoresults showed that the CSDG hydrogel accelerated blood vessel regeneration by upregulating the expression of CD31, IL-6, FGF, and VEGF, thereby promoting rapid healing of wounds. In conclusion, this study successfully prepared the CSDG hydrogel wound dressings, providing a new approach and method for the development of hydrogel dressings based on natural macromolecules.

Cirrhosis remains a significant clinical challenge due to its poor prognosis and limited treatment options, creating a high unmet medical need for the development of novel therapies. In this study, we analyzed the effects of a novel approach to treat cirrhosis using platelet-rich plasma-derived extracellular vesicles (PRPEV) in mice.

PRPEV were collected from platelet-rich plasma using ultrafiltration, and their proteomes were analyzed. The carbon tetrachloride (CCl4)-induced cirrhosis model of mice was used to evaluate the effect of PRPEV administration and compared with the control group (n = 8). In vitro and in vivo mechanistic analyses of PRPEV administration were confirmed using real time-PCR and immunostaining.

Gene ontology analysis based on the proteome revealed that PRPEV contain many factors associated with EV and immune responses. In vitro, PRPEV polarize macrophages into an anti-inflammatory phenotype. Following PRPEV administration, there was a decrease in serum alanine aminotransferase levels and reduction in liver fibrosis, while mRNA levels of regenerative factors were upregulated and transforming growth factor β-1 was downregulated. Furthermore, the number of anti-inflammatory macrophages in the liver increased.

PRPEV may contribute to hepatocyte proliferation, anti-inflammation, and anti-fibrogenesis in the liver. This novel concept paves the way for cirrhosis treatment.

Treatments directly targeting fibrosis remain limited. Given the unique intrinsic features of macrophages and their capacity to engraft in the liver, we genetically engineered bone marrow-derived macrophages with a chimeric antigen receptor (CAR) to direct their phagocytic activity against hepatic stellate cells (HSCs) in multiple mouse models. This study aimed to demonstrate the therapeutic efficacy of CAR macrophages (CAR-Ms) in mouse models of fibrosis and cirrhosis and to elucidate the underlying mechanisms.

uPAR expression was studied in patients with fibrosis/cirrhosis and in murine models of liver fibrosis, including mice treated with carbon tetrachloride, a 5-diethoxycarbonyl-1, 4-dihydrocollidine diet, or a high-fat/cholesterol/fructose diet. The safety and efficacy of CAR-Ms were evaluated in vitro and in vivo.

Adoptive transfer of CAR-Ms resulted in a significant reduction in liver fibrosis and the restoration of function in murine models of liver fibrosis. CAR-Ms modulated the hepatic immune microenvironment to recruit and modify the activation of endogenous immune cells to drive fibrosis regression. These CAR-Ms were able to recruit and present antigens to T cells and mount specific antifibrotic T-cell responses to reduce fibroblasts and liver fibrosis in mice.

Collectively, our findings demonstrate the potential of using macrophages as a platform for CAR technology to provide an effective treatment option for liver fibrosis. CAR-Ms might be developed for treatment of patients with liver fibrosis.

Liver fibrosis is an incurable condition that afflicts millions of people globally. Despite the clear clinical need, therapies for liver fibrosis are limited. Our findings provide the first preclinical evidence that chimeric antigen receptor (CAR)-macrophages (CAR-Ms) targeting uPAR can attenuate liver fibrosis and cirrhosis. We show that macrophages expressing this uPAR CAR exert a direct antifibrotic effect and elicit a specific T-cell response that augments the immune response against liver fibrosis. These findings demonstrate the potential of using CAR-Ms as an effective cell-based therapy for the treatment of liver fibrosis.

Cell therapies are emerging as promising treatments for a range of liver diseases but translational bottlenecks still remain including: securing and assessing the safe and effective delivery of cells to the disease site; ensuring successful cell engraftment and function; and preventing immunogenic responses. Here we highlight three therapies, each utilising a different cell type, at different stages in their clinical translation journey: transplantation of multipotent mesenchymal stromal/signalling cells, hepatocytes and macrophages. To overcome bottlenecks impeding clinical progression, we advocate for wider use of mechanistic in silico modelling approaches. We discuss how in silico approaches, alongside complementary experimental approaches, can enhance our understanding of the mechanisms underlying successful cell delivery and engraftment. Furthermore, such combined theoretical-experimental approaches can be exploited to develop novel therapies, address safety and efficacy challenges, bridge the gap between in vitro and in vivo model systems, and compensate for the inherent differences between animal model systems and humans. We also highlight how in silico model development can result in fewer and more targeted in vivo experiments, thereby reducing preclinical costs and experimental animal numbers and potentially accelerating translation to the clinic. The development of biologically-accurate in silico models that capture the mechanisms underpinning the behaviour of these complex systems must be reinforced by quantitative methods to assess cell survival post-transplant, and we argue that non-invasive in vivo imaging strategies should be routinely integrated into transplant studies.

Current therapy for hepatic injury induced by the accumulation of bile acids is limited. Leucine-rich repeat G protein-coupled receptor 4 (LGR4), also known as GPR48, is critical for cytoprotection and cell proliferation. Here, we reported a novel function for the LGR4 in cholestatic liver injury. In the bile duct ligation (BDL)-induced liver injury model, hepatic LGR4 expression was significantly downregulated. Deficiency of LGR4 in hepatocytes (Lgr4LKO) notably decreased BDL-induced liver injury measured by hepatic necrosis, fibrosis, and circulating liver enzymes and total bilirubin. Levels of total bile acids in plasma and liver were markedly reduced in these mice. However, deficiency of LGR4 in macrophages (Lyz2-Lgr4MKO) demonstrated no significant effect on liver injury induced by BDL. Deficiency of LGR4 in hepatocytes significantly attenuated S1PR2 and the phosphorylation of protein kinase B (AKT) induced by BDL. Recombinant Rspo1 and Rspo3 potentiated the taurocholic acid (TCA)-induced upregulation in S1PR2 and phosphorylation of AKT in hepatocytes. Inhibition of S1PR2-AKT signaling by specific AKT or S1PR2 inhibitors blocked the increase of bile acid secretion induced by Rspo1/3 in hepatocytes. Our studies indicate that the R-spondins (Rspos)-LGR4 signaling in hepatocytes aggravates the cholestatic liver injury by potentiating the production of bile acids in a S1PR2-AKT-dependent manner.NEW & NOTEWORTHY Deficiency of LGR4 in hepatocytes alleviates BDL-induced liver injury. LGR4 in macrophages demonstrates no effect on BDL-induced liver injury. Rspos-LGR4 increases bile acid synthesis and transport via potentiating S1PR2-AKT signaling in hepatocytes.

Macrophage therapy for liver fibrosis is on the cusp of meaningful clinical utility. Due to the heterogeneities of macrophages, it is urgent to develop safer macrophages with a more stable and defined phenotype for the treatment of liver fibrosis. Herein, a new macrophage-based immunotherapy using macrophages stably expressing a pivotal cytokine from Toxoplasma gondii, a parasite that infects ≈ 2 billion people is developed. It is found that Toxoplasma gondii macrophage migration inhibitory factor-transgenic macrophage (Mφtgmif) shows stable fibrinolysis and strong chemotactic capacity. Mφtgmif effectively ameliorates liver fibrosis and deactivates aHSCs by recruiting Ly6Chi macrophages via paracrine CCL2 and polarizing them into the restorative Ly6Clo macrophage through the secretion of CX3CL1. Remarkably, Mφtgmif exhibits even higher chemotactic potential, lower grade of inflammation, and better therapeutic effects than LPS/IFN-γ-treated macrophages, making macrophage-based immune therapy more efficient and safer. Mechanistically, TgMIF promotes CCL2 expression by activating the ERK/HMGB1/NF-κB pathway, and this event is associated with recruiting endogenous macrophages into the fibrosis liver. The findings do not merely identify viable immunotherapy for liver fibrosis but also suggest a therapeutic strategy based on the evolutionarily designed immunomodulator to treat human diseases by modifying the immune microenvironment.

Liver fibrosis is the formation of a fibrous scar due to chronic liver disease including viral hepatitis, alcohol and non-alcoholic fatty liver disease. Without treatment, it will develop into cirrhosis and hepatocellular carcinoma. Up to now, there is no effective way to cure liver fibrosis. Extracellular vesicles (EVs) are biological nanoparticles with potential to be therapeutical agents or delivery tools. A lot of studies have demonstrated the therapeutical effect of EVs on liver fibrosis. In this review, we mainly pay attention to roles of liver non-parenchymal cells in pathology of fibrosis, the basic information about EVs and therapeutical effect on liver fibrosis of EVs when they act on non-parenchymal cells.

Macrophages, an essential cell population involved in mediating innate immunity in the host, play a crucial role on the development of hepatic cirrhosis. Extensive studies have highlighted the potential therapeutic benefits of macrophage therapy in treating hepatic cirrhosis. This review aims to provide a comprehensive overview of the various effects and underlying mechanisms associated with macrophage therapy in the context of hepatic cirrhosis.

Inflammation is a hallmark of progressive liver diseases such as chronic viral or immune-mediated hepatitis, alcohol-associated liver disease, and NAFLD. Preclinical and clinical studies have provided robust evidence that cytokines and related cellular stress sensors in innate and adaptive immunity orchestrate hepatic disease processes. Unresolved inflammation and liver injury result in hepatic scarring, fibrosis, and cirrhosis, which may culminate in HCC. Liver diseases are accompanied by gut dysbiosis and a bloom of pathobionts, fueling hepatic inflammation. Anti-inflammatory strategies are extensively used to treat human immune-mediated conditions beyond the liver, while evidence for immunomodulatory therapies and cell therapy-based strategies in liver diseases is only emerging. The development and establishment of novel immunomodulatory therapies for chronic liver diseases has been dampened by several clinical challenges, such as invasive monitoring of therapeutic efficacy with liver biopsy in clinical trials and risk of DILI in several studies. Such aspects prevented advancements of novel medical therapies for chronic inflammatory liver diseases. New concepts modulating the liver immune environment are studied and eagerly awaited to improve the management of chronic liver diseases in the future.

Metabolic dysfunction-associated steatohepatitis (MASH) is a severe form of liver disease that poses a global health threat because of its potential to progress to advanced fibrosis, leading to cirrhosis and liver cancer. Recent advances in single-cell methodologies, refined disease models, and genetic and epigenetic insights have provided a nuanced understanding of MASH fibrogenesis, with substantial cellular heterogeneity in MASH livers providing potentially targetable cell-cell interactions and behavior. Unlike fibrogenesis, mechanisms underlying fibrosis regression in MASH are still inadequately understood, although antifibrotic targets have been recently identified. A refined antifibrotic treatment framework could lead to noninvasive assessment and targeted therapies that preserve hepatocellular function and restore the liver's architectural integrity.

Chronic liver diseases such as nonalcoholic fatty liver disease (NAFLD) or viral hepatitis are characterized by persistent inflammation and subsequent liver fibrosis. Liver fibrosis critically determines long-term morbidity (for example, cirrhosis or liver cancer) and mortality in NAFLD and nonalcoholic steatohepatitis (NASH). Inflammation represents the concerted response of various hepatic cell types to hepatocellular death and inflammatory signals, which are related to intrahepatic injury pathways or extrahepatic mediators from the gut-liver axis and the circulation. Single-cell technologies have revealed the heterogeneity of immune cell activation concerning disease states and the spatial organization within the liver, including resident and recruited macrophages, neutrophils as mediators of tissue repair, auto-aggressive features of T cells as well as various innate lymphoid cell and unconventional T cell populations. Inflammatory responses drive the activation of hepatic stellate cells (HSCs), and HSC subsets, in turn, modulate immune mechanisms via chemokines and cytokines or transdifferentiate into matrix-producing myofibroblasts. Current advances in understanding the pathogenesis of inflammation and fibrosis in the liver, mainly focused on NAFLD or NASH owing to the high unmet medical need, have led to the identification of several therapeutic targets. In this Review, we summarize the inflammatory mediators and cells in the diseased liver, fibrogenic pathways and their therapeutic implications.

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease characterized by chronic, progressive, and fibrotic lung injury. Although remarkable progress has been made toward understanding the pathogenesis of PF, finding more effective treatments for this fatal disease remains a challenge. In this study, we describe an innovative macrophage-based approach to deliver anti-fibrotic protein to the lung and inhibit PF in a mouse model of bleomycin (BLM)-induced lung injury. We engineered macrophages to continuously secrete three types of proteins: interleukin-10, which prevents inflammation; TGFRcFc, a soluble truncated TGF-βR2 that blocks TGF-β; and CD147, which induces matrix metalloproteinases (MMPs) and causes collagen degradation. Infusing these engineered macrophages into the lungs of BLM-induced PF mouse models in an optimal pattern significantly ameliorated PF in mice. Specifically, the most effective therapeutic outcome was achieved by infusing IL-10-secreting macrophages on day 1, followed by TGFRcFc-secreting macrophages on day 7 and CD147-secreting macrophages on day 14 into the same mice after BLM treatment. Our data suggest that macrophage-based delivery of anti-fibrotic proteins to the lungs is a promising therapy for fibrotic lung disorders.

Liver regeneration is a dynamic and regulated process that involves inflammation, granulation, and tissue remodeling. Hepatic macrophages, abundantly distributed in the liver, are essential components that actively participate in each step to orchestrate liver regeneration. In the homeostatic liver, resident macrophages (Kupffer cells) acquire a tolerogenic phenotype and contribute to immunological tolerance. Following toxicity-induced damage or physical resection, Kupffer cells as well as monocyte-derived macrophages can be activated and promote an inflammatory process that supports the survival and activation of hepatic myofibroblasts and thus promotes scar tissue formation. Subsequently, these macrophages, in turn, exhibit the anti-inflammatory effects critical to extracellular matrix remodeling during the resolution stage. However, continuous damage-induced chronic inflammation generally leads to hepatic macrophage dysfunction, which exacerbates hepatocellular injury and triggers further liver fibrosis and even cirrhosis. Emerging macrophage-targeting strategies have shown efficacy in both preclinical and clinical studies. Increasing evidence indicates that metabolic rewiring provides substrates for epigenetic modification, which endows monocytes/macrophages with prolonged "innate immune memory". Therefore, it is reasonable to conceive novel therapeutic strategies for metabolically reprogramming macrophages and thus mediate a homeostatic or reparative process for hepatic inflammation management and liver regeneration.

Liver cirrhosis can lead to liver failure and eventually death. Macrophages are the main contributors to cirrhosis and have a bidirectional role in regulating matrix deposition and degradation. Macrophage-based cell therapy has been developed as an alternative to liver transplantation. However, there is insufficient evidence regarding its safety and efficacy. In this study, we aimed to explore the effect of combining insulin-like growth factor 2 (IGF2) with bone marrow-derived macrophages (BMDMs) to treat mice with liver cirrhosis.

We assessed liver inflammation, fibrosis regression, liver function, and liver regeneration in mice with CCl4-induced cirrhosis and treated with BMDM only or IGF2 + BMDM. We performed in vitro experiments in which activated hepatic stellate cells (HSCs) were co-cultured with macrophages in the presence or absence of IGF2. The polarity of macrophages and the degree of inhibition of HSCs were examined. The effect of IGF2 on macrophages was also verified by the overexpression of IGF2.

Combining IGF2 with BMDM reduced liver inflammation and fibrosis and increased hepatocyte proliferation. Combining IGF2 with BMDM was more effective than using BMDM alone. In vitro experiments demonstrated that IGF2 inhibited HSCs activation by upregulating NR4A2 to promote the anti-inflammatory macrophages phenotype. IGF2 also increased the synthesis of matrix metalloproteinases (MMPs) by macrophages, which may explain why administering IGF2 combined with BMDM was more effective than administering BMDM only.

Our study provides a theoretical basis for the future use of BMDM-based cell therapy to treat liver cirrhosis.

Liver fibrosis/cirrhosis is significant health burden worldwide, resulting in liver failure or cancer and accounting for many deaths each year. The pathogenesis of liver fibrosis is very complex, which makes treatment challenging. Growth differentiation factor 15 (GDF15), a cysteine knot protein belonging to the transforming growth factor β (TGF-β) superfamily, has been shown to play a protective role after tissue injury and to promote a negative energy balance during obesity and diabetes. However, paucity of literature is available about GDF15 function in liver fibrosis. This study aimed to investigate the immunomodulatory role and therapeutic potential of GDF15 in progression of hepatic fibrosis.

GDF15 expression was studied in patients with fibrosis/cirrhosis and in 2 murine models of liver fibrosis, including mice treated with CCl4 or DDC diet. GDF15 involvement in the pathogenesis of liver fibrosis was assessed in Gdf15 knockout mouse using both CCl4 and DDC diet experimental models. We used the CCl4 and/or DDC diet-induced liver fibrosis model to examine the antifibrotic and anti-inflammatory effects of AAV8-mediated GDF15 overexpression in hepatocytes or recombinant mouse GDF15.

GDF15 expression is decreased in the liver of animal models and patients with liver fibrosis/cirrhosis compared with those without liver disease. In vivo studies showed that GDF15 deficiency aggravated CCl4 and DDC diet-induced liver fibrosis, while GDF15 overexpression mediated by AAV8 or its recombinant protein alleviated CCl4 and/or DDC diet-induced liver fibrosis. In Gdf15 knockout mice, the intrahepatic microenvironment that developed during fibrosis showed relatively more inflammation, as demonstrated by enhanced infiltration of monocytes and neutrophils and increased expression of proinflammatory factors, which could be diminished by AAV8-mediated GDF15 overexpression in hepatocytes. Intriguingly, GDF15 exerts its effects by reprogramming the metabolic pathways of macrophages to acquire an oxidative phosphorylation-dependent anti-inflammatory functional fate. Furthermore, adoptive transfer of GDF15-preprogrammed macrophages to mouse models of liver fibrosis induced by CCl4 attenuated inflammation and alleviated the progression of liver fibrosis.

GDF15 ameliorates liver fibrosis via modulation of liver macrophages. Our data implicate the importance of the liver microenvironment in macrophage programming during liver fibrosis and suggest that GDF15 is a potentially attractive therapeutic target for the treatment of patients with liver fibrosis.

Advanced chronic liver disease is characterised by a long compensated phase followed by a rapidly progressive 'decompensated' phase, which is marked by the development of complications of portal hypertension and liver dysfunction. Advanced chronic liver disease is considered responsible for more than one million deaths annually worldwide. No treatment is available to specifically target fibrosis and cirrhosis; liver transplantation remains the only curative option. Researchers are investigating strategies to restore liver functionality to avoid or slow progression towards end-stage liver disease. Cytokine mobilisation of stem cells from the bone marrow to the liver could improve liver function. Granulocyte colony-stimulating factor (G-CSF) is a 175-amino-acid protein currently available for mobilisation of haematopoietic stem cells from the bone marrow. Multiple courses of G-CSF, with or without stem or progenitor cell or growth factors (erythropoietin or growth hormone) infusion, might be associated with accelerated hepatic regeneration, improved liver function, and survival.

To evaluate the benefits and harms of G-CSF with or without stem or progenitor cell or growth factors (erythropoietin or growth hormone) infusion, compared with no intervention or placebo in people with compensated or decompensated advanced chronic liver disease.

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, three other databases, and two trial registers (October 2022) together with reference-checking and web-searching to identify additional studies. We applied no restrictions on language and document type.

We only included randomised clinical trials comparing G-CSF, independent of the schedule of administration, as a single treatment or combined with stem or progenitor cell infusion, or with other medical co-interventions, with no intervention or placebo, in adults with chronic compensated or decompensated advanced chronic liver disease or acute-on-chronic liver failure. We included trials irrespective of publication type, publication status, outcomes reported, or language.

We followed standard Cochrane procedures. All-cause mortality, serious adverse events, and health-related quality of life were our primary outcomes, and liver disease-related morbidity, non-serious adverse events, and no improvement of liver function scores were our secondary outcomes. We undertook meta-analyses, based on intention-to-treat, and presented results using risk ratios (RR) for dichotomous outcomes and the mean difference (MD) for continuous outcomes, with 95% confidence intervals (CI) and I2 statistic values as a marker of heterogeneity. We assessed all outcomes at maximum follow-up. We determined the certainty of evidence using GRADE, evaluated the risk of small-study effects in regression analyses, and conducted subgroup and sensitivity analyses.

We included 20 trials (1419 participants; sample size ranged from 28 to 259), which lasted between 11 and 57 months. Nineteen trials included only participants with decompensated cirrhosis; in one trial, 30% had compensated cirrhosis. The included trials were conducted in Asia (15), Europe (four), and the USA (one). Not all trials provided data for our outcomes. All trials reported data allowing intention-to-treat analyses. The experimental intervention consisted of G-CSF alone or G-CSF plus any of the following: growth hormone, erythropoietin, N-acetyl cysteine, infusion of CD133-positive haemopoietic stem cells, or infusion of autologous bone marrow mononuclear cells. The control group consisted of no intervention in 15 trials and placebo (normal saline) in five trials. Standard medical therapy (antivirals, alcohol abstinence, nutrition, diuretics, β-blockers, selective intestinal decontamination, pentoxifylline, prednisolone, and other supportive measures depending on the clinical status and requirement) was administered equally to the trial groups. Very low-certainty evidence suggested a decrease in mortality with G-CSF, administered alone or in combination with any of the above, versus placebo (RR 0.53, 95% CI 0.38 to 0.72; I2 = 75%; 1419 participants; 20 trials). Very low-certainty evidence suggested no difference in serious adverse events (G-CSF alone or in combination versus placebo: RR 1.03, 95% CI 0.66 to 1.61; I2 = 66%; 315 participants; three trials). Eight trials, with 518 participants, reported no serious adverse events. Two trials, with 165 participants, used two components of the quality of life score for assessment, with ranges from 0 to 100, where higher scores indicate better quality of life, with a mean increase from baseline of the physical component summary of 20.7 (95% CI 17.4 to 24.0; very low-certainty evidence) and a mean increase from baseline of the mental component summary of 27.8 (95% CI 12.3 to 43.3; very low-certainty evidence). G-CSF, alone or in combination, suggested a beneficial effect on the proportion of participants who developed one or more liver disease-related complications (RR 0.40, 95% CI 0.17 to 0.92; I2 = 62%; 195 participants; four trials; very low-certainty evidence). When we analysed the occurrences of single complications, there was no suggestion of a difference between G-CSF, alone or in combination, versus control, in participants in need of liver transplantation (RR 0.85, 95% CI 0.39 to 1.85; 692 participants; five trials), in the development of hepatorenal syndrome (RR 0.65, 95% CI 0.33 to 1.30; 520 participants; six trials), in the occurrence of variceal bleeding (RR 0.68, 95% CI 0.37 to 1.23; 614 participants; eight trials), and in the development of encephalopathy (RR 0.56, 95% CI 0.31 to 1.01; 605 participants; seven trials) (very low-certainty evidence). The same comparison suggested that G-CSF reduces the development of infections (including sepsis) (RR 0.50, 95% CI 0.29 to 0.84; 583 participants; eight trials) and does not improve liver function scores (RR 0.67, 95% CI 0.53 to 0.86; 319 participants; two trials) (very low-certainty evidence).

G-CSF, alone or in combination, seems to decrease mortality in people with decompensated advanced chronic liver disease of whatever aetiology and with or without acute-on-chronic liver failure, but the certainty of evidence is very low because of high risk of bias, inconsistency, and imprecision. The results of trials conducted in Asia and Europe were discrepant; this could not be explained by differences in participant selection, intervention, and outcome measurement. Data on serious adverse events and health-related quality of life were few and inconsistently reported. The evidence is also very uncertain regarding the occurrence of one or more liver disease-related complications. We lack high-quality, global randomised clinical trials assessing the effect of G-CSF on clinically relevant outcomes.

Liver disease is prevalent worldwide. When it reaches the end stage, mortality rises to 50% or more. Although liver transplantation has emerged as the most efficient treatment for end-stage liver disease, its application has been limited by the scarcity of donor livers. The lack of acceptable donor organs implies that patients are at high risk while waiting for suitable livers. In this scenario, cell therapy has emerged as a promising treatment approach. Most of the time, transplanted cells can replace host hepatocytes and remodel the hepatic microenvironment. For instance, hepatocytes derived from donor livers or stem cells colonize and proliferate in the liver, can replace host hepatocytes, and restore liver function. Other cellular therapy candidates, such as macrophages and mesenchymal stem cells, can remodel the hepatic microenvironment, thereby repairing the damaged liver. In recent years, cell therapy has transitioned from animal research to early human studies. In this review, we will discuss cell therapy in end-stage liver disease treatment, especially focusing on various cell types utilized for cell transplantation, and elucidate the processes involved. Furthermore, we will also summarize the practical obstacles of cell therapy and offer potential solutions.