Multipotent mesenchymal stromal cells: A promising strategy to manage alcoholic liver disease

Innovative Strategies for Liver Transplantation: The Role of Mesenchymal Stem Cells and Their Cell-Free Derivatives

Despite being the standard treatment for end-stage liver disease, liver transplantation has limitations like donor scarcity, high surgical costs, and immune rejection risks. Mesenchymal stem cells (MSCs) and their derivatives offer potential for liver regeneration and transplantation. MSCs, known for their multipotency, low immunogenicity, and ease of obtainability, can differentiate into hepatocyte-like cells and secrete bioactive factors that promote liver repair and reduce immune rejection. However, the clinical application of MSCs is limited by risks such as aberrant differentiation and low engraftment rates. As a safer alternative, MSC-derived secretomes and extracellular vesicles (EVs) offer promising therapeutic benefits, including enhanced graft survival, immunomodulation, and reduced ischemia-reperfusion injury. Current research highlights the efficacy of MSC-derived therapies in improving liver transplant outcomes, but further studies are necessary to standardize clinical applications. This review highlights the potential of MSCs and EVs to address key challenges in liver transplantation, paving the way for innovative therapeutic strategies.

Tumor necrosis factor-inducible gene 6 protein and its derived peptide ameliorate liver fibrosis by repressing CD44 activation in mice with alcohol-related liver disease

BACKGROUND

Alcohol-related liver disease (ALD) is a major health concern worldwide, but effective therapeutics for ALD are still lacking. Tumor necrosis factor-inducible gene 6 protein (TSG-6), a cytokine released from mesenchymal stem cells, was shown to reduce liver fibrosis and promote successful liver repair in mice with chronically damaged livers. However, the effect of TSG-6 and the mechanism underlying its activity in ALD remain poorly understood.

METHODS

To investigate its function in ALD mice with fibrosis, male mice chronically fed an ethanol (EtOH)-containing diet for 9 weeks were treated with TSG-6 (EtOH + TSG-6) or PBS (EtOH + Veh) for an additional 3 weeks.

RESULTS

Severe hepatic injury in EtOH-treated mice was markedly decreased in TSG-6-treated mice fed EtOH. The EtOH + TSG-6 group had less fibrosis than the EtOH + Veh group. Activation of cluster of differentiation 44 (CD44) was reported to promote HSC activation. CD44 and nuclear CD44 intracellular domain (ICD), a CD44 activator which were upregulated in activated HSCs and ALD mice were significantly downregulated in TSG-6-exposed mice fed EtOH. TSG-6 interacted directly with the catalytic site of MMP14, a proteolytic enzyme that cleaves CD44, inhibited CD44 cleavage to CD44ICD, and reduced HSC activation and liver fibrosis in ALD mice. In addition, a novel peptide designed to include a region that binds to the catalytic site of MMP14 suppressed CD44 activation and attenuated alcohol-induced liver injury, including fibrosis, in mice.

CONCLUSIONS

These results demonstrate that TSG-6 attenuates alcohol-induced liver damage and fibrosis by blocking CD44 cleavage to CD44ICD and suggest that TSG-6 and TSG-6-mimicking peptide could be used as therapeutics for ALD with fibrosis.

Human umbilical cord-derived mesenchymal stem cells for the treatment of decompensated cirrhosis (MSC-DLC-1): a dose-escalation, phase I trial protocol

INTRODUCTION

There are limited therapeutic options to efficiently treat patients with decompensated liver cirrhosis. This trial aims to explore the efficacy and safety of human umbilical cord-derived mesenchymal stem cells (UC-MSCs) for the treatment of patients with decompensated liver cirrhosis.

METHODS AND ANALYSIS

This study is an open-label, dose-escalation, one-armed phase I trial. A single injection of UC-MSCs will be administered in a predetermined dose in each cohort (5.0×107, 1.0×108, 1.5×108 or 2.0×108 cells) according to the '3+3' rule. The primary evaluation measures will include the incidence of adverse events and the change in the Model for End-stage Liver Disease (MELD) score from baseline to the 28th day. Secondary evaluation measures will be evaluated at baseline and at each follow-up point. These measures will include the change in the MELD score from baseline to each follow-up point, the incidence of each complication associated with decompensated cirrhosis, liver transplant-free survival and the incidence of liver failure, among other relevant measures. All patients will be followed up for 24 months. This study will evaluate whether the use of UC-MSCs to treat patients with decompensated liver cirrhosis is safe and tolerable.

ETHICS AND DISSEMINATION

The study has been approved by the Chinese People's Liberation Army General Hospital (Approval#: 2018-107-D-4). Once conducted, the results from the study will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT05227846.

Multiple Dimensions of using Mesenchymal Stem Cells for Treating Liver Diseases: From Bench to Beside

Liver diseases impose a huge burden worldwide. Although hepatocyte transplantation has long been considered as a potential strategy for treating liver diseases, its clinical implementation has created some obvious limitations. As an alternative strategy, cell therapy, particularly mesenchymal stem cell (MSC) transplantation, is widely used in treating different liver diseases, including acute liver disease, acute-on-chronic liver failure, hepatitis B/C virus, autoimmune hepatitis, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. Here, we summarize the status of MSC transplantation in treating liver diseases, focusing on the therapeutic mechanisms, including differentiation into hepatocyte-like cells, immunomodulating function with a variety of immune cells, paracrine effects via the secretion of various cytokines and extracellular vesicles, and facilitation of homing and engraftment. Some improved perspectives and current challenges are also addressed. In summary, MSCs have great potential in the treatment of liver diseases based on their multi-faceted characteristics, and more accurate mechanisms and novel therapeutic strategies stemming from MSCs will facilitate clinical practice.

Current Therapeutic Options and Potential of Mesenchymal Stem Cell Therapy for Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a globally prevalent chronic liver disease caused by chronic or binge consumption of alcohol. The therapeutic efficiency of current therapies for ALD is limited, and there is no FDA-approved therapy for ALD at present. Various strategies targeting pathogenic events in the progression of ALD are being investigated in preclinical and clinical trials. Recently, mesenchymal stem cells (MSCs) have emerged as a promising candidate for ALD treatment and have been tested in several clinical trials. MSC-released factors have captured attention, as they have the same therapeutic function as MSCs. Herein, we focus on current therapeutic options, recently proposed strategies, and their limitations in ALD treatment. Also, we review the therapeutic effects of MSCs and those of MSC-related secretory factors on ALD. Although accumulating evidence suggests the therapeutic potential of MSCs and related factors in ALD, the mechanisms underlying their actions in ALD have not been well studied. Further investigations of the detailed mechanisms underlying the therapeutic role of MSCs in ALD are required to expand MSC therapies to clinical applications. This review provides information on current or possible treatments for ALD and contributes to our understanding of the development of effective and safe treatments for ALD.

Mesenchymal stem cells-based therapy in liver diseases

Multiple immune cells and their products in the liver together form a complex and unique immune microenvironment, and preclinical models have demonstrated the importance of imbalances in the hepatic immune microenvironment in liver inflammatory diseases and immunocompromised liver diseases. Various immunotherapies have been attempted to modulate the hepatic immune microenvironment for the purpose of treating liver diseases. Mesenchymal stem cells (MSCs) have a comprehensive and plastic immunomodulatory capacity. On the one hand, they have been tried for the treatment of inflammatory liver diseases because of their excellent immunosuppressive capacity; On the other hand, MSCs have immune-enhancing properties in immunocompromised settings and can be modified into cellular carriers for targeted transport of immune enhancers by genetic modification, physical and chemical loading, and thus they are also used in the treatment of immunocompromised liver diseases such as chronic viral infections and hepatocellular carcinoma. In this review, we discuss the immunological basis and recent strategies of MSCs for the treatment of the aforementioned liver diseases. Specifically, we update the immune microenvironment of the liver and summarize the distinct mechanisms of immune microenvironment imbalance in inflammatory diseases and immunocompromised liver diseases, and how MSCs can fully exploit their immunotherapeutic role in liver diseases with both immune imbalance patterns.

Alcohol-Related Liver Disease: Basic Mechanisms and Clinical Perspectives

Alcohol-related liver disease (ALD) refers to the liver damage occurring due to excessive alcohol consumption and involves a broad spectrum of diseases that includes liver steatosis, steatohepatitis, hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). The progression of ALD is mainly associated with the amount and duration of alcohol usage; however, it is also influenced by genetic, epigenetic, and environmental factors. The definite diagnosis of ALD is based on a liver biopsy, although several non-invasive diagnostic tools and serum biomarkers have emerging roles in the early detection of ALD. While alcohol abstinence and nutritional support remain the cornerstone of ALD treatment, growing evidence has revealed that the therapeutic agents that target oxidative stress or gut-liver axis, inflammatory response inhibition, and liver regeneration enhancement also play a role in ALD management. Furthermore, microRNAs modulation and mesenchymal stem cell-based therapy have emerging potential as ALD therapeutic options. This review summarizes the updated understanding of the pathophysiology, diagnosis, and novel therapeutic approaches for ALD.

Liver regeneration and alcoholic liver disease

Alcoholic liver diseases (ALD) are a wide spectrum of liver diseases caused by excessive alcohol consumption, from steatosis to cirrhosis. The pathogenesis of ALD is insufficiently understood, but mainly involves oxidative stress, inflammation, bacterial translocation, cell death, and impaired regeneration. Despite numerous attempts to improve patient prognosis, the treatment of advanced ALD is still based on abstinence, brief exposure to corticosteroids, or liver transplantation. However, poor response to corticosteroids and the shortage of liver donors leaves patients helpless towards the end stages. Advances in basic research have contributed to a better understanding of ALD pathophysiology, which offers new options for treatment. In recent years, several therapies related to liver regeneration have been tested with promising prospects, including molecule-induced liver regeneration, stem cell transplantation, and full-function 3D artificial liver assembly. This review discusses mechanisms underlying ALD that can be considered therapeutic targets for regeneration-based treatments.

Pathogenesis, Early Diagnosis, and Therapeutic Management of Alcoholic Liver Disease

Alcoholic liver disease (ALD) refers to the damages to the liver and its functions due to alcohol overconsumption. It consists of fatty liver/steatosis, alcoholic hepatitis, steatohepatitis, chronic hepatitis with liver fibrosis or cirrhosis, and hepatocellular carcinoma. However, the mechanisms behind the pathogenesis of alcoholic liver disease are extremely complicated due to the involvement of immune cells, adipose tissues, and genetic diversity. Clinically, the diagnosis of ALD is not yet well developed. Therefore, the number of patients in advanced stages has increased due to the failure of proper early detection and treatment. At present, abstinence and nutritional therapy remain the conventional therapeutic interventions for ALD. Moreover, the therapies which target the TNF receptor superfamily, hormones, antioxidant signals, and MicroRNAs are used as treatments for ALD. In particular, mesenchymal stem cells (MSCs) are gaining attention as a potential therapeutic target of ALD. Therefore, in this review, we have summarized the current understandings of the pathogenesis and diagnosis of ALD. Moreover, we also discuss the various existing treatment strategies while focusing on promising therapeutic approaches for ALD.

Pre-activation of TLR3 enhances the therapeutic effect of BMMSCs through regulation the intestinal HIF-2α signaling pathway and balance of NKB cells in experimental alcoholic liver injury

Increased intestinal permeability and immune disorder are important mechanisms of alcoholic liver disease (ALD). Recent evidences suggest bone marrow derived mesenchymal stem cells (BMMSCs) have protective effects on end-stage liver disease and intestinal barrier injury. Moreover, the activation of toll-like receptor 3 (TLR3) has been shown enhancing therapeutic effects of BMMSCs in inflammatory bowel disease (IBD). However, the mechanism remains unclear. In current study, chronic-binge alcohol abuse model was employed to investigate the therapeutic effects of BMMSCs and BMMSCs pre-activated with TLR3 (P-BMMSCs) on alcohol-induced liver and intestine damage. C57BL/6 mice were divided into four groups with normal control, alcohol-fed model, alcohol-fed model with BMMSCs treatment and alcohol-fed model with P-BMMSCs treatment. Alcohol-fed mice were fed Lieber-DeCali diet containing 5% alcohol for four weeks and given alcohol intragastrically on the 28th day, but control group were fed isocaloric diet. BMMSCs and P-BMMSCs were injected into the treatment group three times. Results showed alcohol diet causing significant damage to intestinal barrier and liver. These were reversed by the treatment of BMMSCs, especially P-BMMSCs. Moreover, alcohol increased the expression of intestinal HIF-2α, the proportion of NKB cells and the level of serum IL-18, while BMMSCs or P-BMMSCs reduced these factors. In conclusion, BMMSCs, especially TLR3 pre-activated BMMSCs could be used to protect alcohol-induced intestine and liver injury.

Extracorporeal cellular therapy (ELAD) in severe alcoholic hepatitis: A multinational, prospective, controlled, randomized trial

Severe alcoholic hepatitis (sAH) is associated with a poor prognosis. There is no proven effective treatment for sAH, which is why early transplantation has been increasingly discussed. Hepatoblastoma-derived C3A cells express anti-inflammatory proteins and growth factors and were tested in an extracorporeal cellular therapy (ELAD) study to establish their effect on survival for subjects with sAH. Adults with sAH, bilirubin ≥8 mg/dL, Maddrey's discriminant function ≥ 32, and Model for End-Stage Liver Disease (MELD) score ≤ 35 were randomized to receive standard of care (SOC) only or 3-5 days of continuous ELAD treatment plus SOC. After a minimum follow-up of 91 days, overall survival (OS) was assessed by using a Kaplan-Meier survival analysis. A total of 203 subjects were enrolled (96 ELAD and 107 SOC) at 40 sites worldwide. Comparison of baseline characteristics showed no significant differences between groups and within subgroups. There was no significant difference in serious adverse events between the 2 groups. In an analysis of the intent-to-treat population, there was no difference in OS (51.0% versus 49.5%). The study failed its primary and secondary end point in a population with sAH and with a MELD ranging from 18 to 35 and no upper age limit. In the prespecified analysis of subjects with MELD < 28 (n = 120), ELAD was associated with a trend toward higher OS at 91 days (68.6% versus 53.6%; P = .08). Regression analysis identified high creatinine and international normalized ratio, but not bilirubin, as the MELD components predicting negative outcomes with ELAD. A new trial investigating a potential benefit of ELAD in younger subjects with sufficient renal function and less severe coagulopathy has been initiated. Liver Transplantation 24 380-393 2018 AASLD.

Mesenchymal stromal cell-derived exosome-rich fractionated secretome confers a hepatoprotective effect in liver injury

BACKGROUND

Mesenchymal stromal cells (MSCs) are an attractive therapeutic agent in regenerative medicine. Recently, there has been a paradigm shift from differentiation of MSCs to their paracrine effects at the injury site. Several reports elucidate the role of trophic factors secreted by MSCs toward the repair of injured tissues. We hypothesize that fractionating the MSC secretome will enrich exosomes containing soluble bioactive molecules, improving its therapeutic potential for liver failure.

METHODS

Rat bone marrow MSCs were isolated and the conditioned media filtered, concentrated and ultracentrifuged to generate fractionated secretome. This secretome was characterized for the presence of exosomes and recovery from liver injury assessed in in-vitro liver injury models. The results were further validated in vivo.

RESULTS

Studies on in-vitro liver injury models using acetaminophen and hydrogen peroxide show better cell recovery and reduced cytotoxicity in the presence of fractionated as opposed to unfractionated secretome. Further, the cells showed reduced oxidative stress in the presence of fractionated secretome, suggesting a potential antioxidative effect. These results were further validated in vivo in liver failure models, wherein improved liver regeneration in the presence of fractionated secretome (0.819 ± 0.035) was observed as compared to unfractionated secretome (0.718 ± 0.042).

CONCLUSIONS

The work presented is a proof of concept that fractionating the secretome enriches certain bioactive molecules involved in the repair and recovery of injured liver tissue. Exosome enriched mesenchymal stromal cell-derived fractionated secretome potentiates recovery upon injection in injured liver.

Mesenchymal stem cells rescue acute hepatic failure by polarizing M2 macrophages

AIM

To investigate whether M1 or M2 polarization contributes to the therapeutic effects of mesenchymal stem cells (MSCs) in acute hepatic failure (AHF).

METHODS

MSCs were transfused into rats with AHF induced by D-galactosamine (DGalN). The therapeutic effects of MSCs were evaluated based on survival rate and hepatocyte proliferation and apoptosis. Hepatocyte regeneration capacity was evaluated by the expression of the hepatic progenitor surface marker epithelial cell adhesion molecule (EpCAM). Macrophage polarization was analyzed by M1 markers [CD68, tumor necrosis factor alpha (TNF-α), interferon-γ (IFN-γ), inducible nitric oxide synthase (INOS)] and M2 markers [CD163, interleukin (IL)-4, IL-10, arginase-1 (Arg-1)] in the survival and death groups after MSC transplantation.

RESULTS

The survival rate in the MSC-treated group was increased compared with the DPBS-treated control group (37.5% vs 10%). MSC treatment protected rats with AHF by reducing apoptotic hepatocytes and promoting hepatocyte regeneration. Immunohistochemical analysis showed that MSC treatment significantly increased the expression of EpCAM compared with the control groups (P < 0.001). Expression of EpCAM in the survival group was significantly up-regulated compared with the death group after MSC transplantation (P = 0.003). Transplantation of MSCs significantly improved the expression of CD163 and increased the gene expression of IL-10 and Arg-1 in the survival group. IL-4 concentrations were significantly increased compared to the death group after MSC transplantation (88.51 ± 24.51 pg/mL vs 34.61 ± 6.6 pg/mL, P < 0.001). In contrast, macrophages showed strong expression of CD68, TNF-α, and INOS in the death group. The concentration of IFN-γ was significantly increased compared to the survival group after MSC transplantation (542.11 ± 51.59 pg/mL vs 104.07 ± 42.80 pg/mL, P < 0.001).

CONCLUSION

M2 polarization contributes to the therapeutic effects of MSCs in AHF by altering levels of anti-inflammatory and pro-inflammatory factors.

Mesenchymal Stem Cells and Myeloid Derived Suppressor Cells: Common Traits in Immune Regulation

To protect host against immune-mediated damage, immune responses are tightly regulated. The regulation of immune responses is mediated by various populations of mature immune cells, such as T regulatory cells and B regulatory cells, but also by immature cells of different origins. In this review, we discuss regulatory properties and mechanisms whereby two distinct populations of immature cells, mesenchymal stem cells, and myeloid derived suppressor cells mediate immune regulation, focusing on their similarities, discrepancies, and potential clinical applications.