Bone marrow-derived mesenchymal stem cell therapy for decompensated liver cirrhosis: A meta-analysis

Efficacy and safety of mesenchymal stem cell therapy in acute on chronic liver failure: a systematic review and meta-analysis of randomized controlled clinical trials

BACKGROUND

Acute-on-chronic liver failure has become a serious global health burden, which is characterized by an acute deterioration of liver function, rapidly evolving organ failure, and high short-term mortality in patients with chronic liver disease. The pathogenesis includes extensive hepatic necrosis, which is related to intense systemic inflammation and subsequently causes the inflammatory cytokine storm, resulting in portal hypertension, organ dysfunction, and organ failure. Mesenchymal stem cells can function as seed cells to remodel and repair damaged liver tissues, thus showing potential therapeutic alternatives for patients with chronic liver disease. However, standard treatment protocols for mesenchymal stem cells in acute-on-chronic liver failure patients have not been established.

METHODS

We conducted a detailed search from PubMed/Medline, Web of Science, EMBASE, and Cochrane Library to find randomized controlled trials published before October 23, 2021. We formulated criteria for the literature screening according to the PICOS principle (Population, Intervention, Comparison, Outcome, Study design). Subsequently, the bias risk assessment tool was used to assess the quality of all enrolled studies. Finally, outcome measurements including the model of end-stage liver disease score, albumin, total bilirubin, coagulation function, and aminotransferase were extracted for statistical analysis.

RESULTS

A total of 7 clinical trials were included. The results of enrolled studies indicated that patients with acute-on-chronic liver failure who received mesenchymal stem cells inoculation showed a decreased MELD score in 4 weeks and 24 weeks, compared with counterparts who received conventional treatment. Reciprocally, mesenchymal stem cells inoculation improved the ALB levels in 4 weeks and 24 weeks. For secondary indicators, mesenchymal stem cells treatment significantly reduced INR levels and ALT levels, compared with the control group. Our results showed no significant differences in the incidence of adverse reactions or serious adverse events monitored in patients after mesenchymal stem cells inoculation.

CONCLUSION

This meta-analysis indicated that mesenchymal stem cell infusion is effective and safe in the treatment of patients with acute-on-chronic liver failure. Without increasing the incidence of adverse events or serious adverse events, MSC treatment improved liver function including a decrease in MELD score and an increase in ALB levels in patients with acute-on-chronic liver failure. However, large-cohort randomized controlled trials with longer follow-up periods are required to further confirm our conclusions.

New insights on mesenchymal stem cells therapy from the perspective of the pathogenesis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) manifests as chronic hepatic steatosis, occurring variably across people due to racial and genetic diversity. It represents a stage in the development of chronic liver disease, marked by fat accumulation, inflammatory responses, oxidative stress in the endoplasmic reticulum, and fibrosis as primary concerns. Understanding its underlying mechanisms remains a challenging and pivotal area of study. In the past, acute liver injury-related diseases were commonly treated with methods such as liver transplantation. However, the emergence of artificial liver has shifted focus to stem cell therapies. Unlike conventional drugs, stem cell therapies are continuously evolving. Despite being classified as drugs, stem cells demonstrated significant efficacy after multiple injections. Mesenchymal stem cells, unlike other types of stem cells, do not have the risk of tumor formation and low immunogenicity, reducing the hypersensitivity reactions associated with liver transplantation. Increasingly, studies suggest that mesenchymal stem cells hold promise in the treatment of chronic liver injury diseases. This review focuses on investigating the role of mesenchymal stem cells in chronic metabolic liver diseases, such as non-alcoholic fatty liver disease, and delves into their specific functions.

Efficacy of stem cell therapy in patients with chronic liver disease: an umbrella review of systematic reviews

BACKGROUND

Stem cell therapy offers promising benefits like modulating immune responses, reducing inflammation, and aiding liver regeneration. This umbrella review seeks to compile evidence from systematic reviews to assess the efficacy of stem cell therapy for improving liver function and survival rates in chronic liver disease patients.

METHODS

We searched electronic databases up to February 15, 2024. The selection process focused on systematic reviews comparing stem cell therapy with standard care or a placebo. The primary outcomes evaluated were changes in liver enzymes, the Model for End-Stage Liver Disease score, and survival rates. Nested Knowledge software was utilized for screening and data extraction. All statistical analyses were performed using R software, version 4.3.

RESULTS

Our umbrella review included 28 systematic reviews. The meta-analysis showcased a notable improvement in survival rates with a pooled relative risk of 1.487 [95% confidence interval (CI): 1.281-1.727). In nonrandomized studies, albumin levels exhibited a standardized mean difference (SMD) of 0.786 (95% CI: 0.368-1.204), indicating positive therapeutic effects. For alanine aminotransferase, the meta-analysis revealed a decrease in levels with an SMD of -0.499 (95% CI: -0.834 to -0.164), and for aspartate aminotransferase, an overall SMD of -0.362 (95% CI: -0.659 to -0.066) was observed, suggesting hepatoprotective effects. No significant changes were observed in total bilirubin levels and Model for End-Stage Liver Disease scores in randomized controlled trials.

CONCLUSION

Stem cell therapy exhibits potential as a novel treatment for chronic liver diseases, as it has demonstrated improvements in survival rates and certain liver function markers. More high-quality randomized controlled trials are needed in the future to fully ascertain the efficacy of stem cell therapy in this patient population.

Therapeutic potential of stem cells in regeneration of liver in chronic liver diseases: Current perspectives and future challenges

The deposition of extracellular matrix and hyperplasia of connective tissue characterizes chronic liver disease called hepatic fibrosis. Progression of hepatic fibrosis may lead to hepatocellular carcinoma. At this stage, only liver transplantation is a viable option. However, the number of possible liver donors is less than the number of patients needing transplantation. Consequently, alternative cell therapies based on non-stem cells (e.g., fibroblasts, chondrocytes, keratinocytes, and hepatocytes) therapy may be able to postpone hepatic disease, but they are often ineffective. Thus, novel stem cell-based therapeutics might be potentially important cutting-edge approaches for treating liver diseases and reducing patient' suffering. Several signaling pathways provide targets for stem cell interventions. These include pathways such as TGF-β, STAT3/BCL-2, NADPH oxidase, Raf/MEK/ERK, Notch, and Wnt/β-catenin. Moreover, mesenchymal stem cells (MSCs) stimulate interleukin (IL)-10, which inhibits T-cells and converts M1 macrophages into M2 macrophages, producing an anti-inflammatory environment. Furthermore, it inhibits the action of CD4+ and CD8+ T cells and reduces the activity of TNF-α and interferon cytokines by enhancing IL-4 synthesis. Consequently, the immunomodulatory and anti-inflammatory capabilities of MSCs make them an attractive therapeutic approach. Importantly, MSCs can inhibit the activation of hepatic stellate cells, causing their apoptosis and subsequent promotion of hepatocyte proliferation, thereby replacing dead hepatocytes and reducing liver fibrosis. This review discusses the multidimensional therapeutic role of stem cells as cell-based therapeutics in liver fibrosis.

Efficacy and safety of mesenchymal stem cell therapy in liver cirrhosis: a systematic review and meta-analysis

AIM

Although the efficacy and safety of mesenchymal stem cell therapy for liver cirrhosis have been demonstrated in several studies. Clinical cases of mesenchymal stem cell therapy for patients with liver cirrhosis are limited and these studies lack the consistency of treatment effects. This article aimed to systematically investigate the efficacy and safety of mesenchymal stem cells in the treatment of liver cirrhosis.

METHOD

The data source included PubMed/Medline, Web of Science, EMBASE, and Cochrane Library, from inception to May 2023. Literature was screened by the PICOS principle, followed by literature quality evaluation to assess the risk of bias. Finally, the data from each study's outcome indicators were extracted for a combined analysis. Outcome indicators of the assessment included liver functions and adverse events. Statistical analysis was performed using Review Manager 5.4.

RESULTS

A total of 11 clinical trials met the selection criteria. The pooled analysis' findings demonstrated that both primary and secondary indicators had improved. Compared to the control group, infusion of mesenchymal stem cells significantly increased ALB levels in 2 weeks, 1 month, 3 months, and 6 months, and significantly decreased MELD score in 1 month, 2 months, and 6 months, according to a subgroup analysis using a random-effects model. Additionally, the hepatic arterial injection favored improvements in MELD score and ALB levels. Importantly, none of the included studies indicated any severe adverse effects.

CONCLUSION

The results showed that mesenchymal stem cell was effective and safe in the treatment of liver cirrhosis, improving liver function (such as a decrease in MELD score and an increase in ALB levels) in patients with liver cirrhosis and exerting protective effects on complications of liver cirrhosis and the incidence of hepatocellular carcinoma. Although the results of the subgroup analysis were informative for the selection of mesenchymal stem cells for clinical treatment, a large number of high-quality randomized controlled trials validations are still needed.

Stem cell-conditioned medium is a promising treatment for Alzheimer's disease

BACKGROUND AND AIM

Alzheimer's disease (AD), a prevalent progressive neurodegenerative disease, is mainly characterized by dementia, memory loss, and cognitive disorder. Rising research was performed to develop pharmacological or non-pharmacological approaches to treat or improve AD complications. Mesenchymal stem cells (MSCs) are stromal cells that can self-renew and exhibit multilineage differentiation. Recent evidence suggested that some of the therapeutic effects of MSCs are mediated by the secreted paracrine factors. These paracrine factors, called MSC- conditioned medium (MSC-CM), may stimulate endogenous repair, promote angio- and artery genesis, and reduce apoptosis through paracrine mechanisms. The current study aims to systematically review the advantages of MSC-CM to the development of research and therapeutic concepts for AD management.

MATERIAL AND METHODS

The present systematic review was performed using PubMed, Web of Science, and Scopus from April 2020 to May 2022 following the "Preferred Reporting Items for Systematic Reviews" (PRISMA) guidelines. The keywords, including "Conditioned medium OR Conditioned media OR Stem cell therapy" AND "Alzheimer's," was searched, and finally, 13 papers were extracted.

RESULTS

The obtained data revealed that MSC-CMs might positively affect neurodegenerative diseases prognosis, especially AD, through various mechanisms, including a decrease in neuro-inflammation, reduction of oxidative stress and Aβ formation, modulation of Microglia function and count, reduction of apoptosis, induction of synaptogenesis and neurogenesis. Also, the results showed that MSC-CM administration could significantly improve cognitive and memory function, increase the expression of neurotrophic factors, decrease the production of pro-inflammatory cytokines, improve mitochondrial function, reduce cytotoxicity, and increase neurotransmitter levels.

CONCLUSION

While inhibiting the induction of neuroinflammation could be considered the first therapeutic effect of CMs, the prevention of apoptosis could be regarded as the most crucial effect of CMs on AD improvement.

The Effects of Programmed Cell Death of Mesenchymal Stem Cells on the Development of Liver Fibrosis

Mesenchymal stem cells have shown noticeable potential for unlimited self-renewal. They can differentiate into specific somatic cells, integrate into target tissues via cell-cell contact, paracrine effects, exosomes, and other processes and then regulate the target cells and tissues. Studies have demonstrated that transplantation of MSCs could decrease the expression and concentration of collagen in the liver, thereby reducing liver fibrosis. A growing body of evidence indicates that apoptotic MSCs could inhibit harmful immune responses and reduce inflammatory responses more effectively than viable MSCs. Accumulating evidence suggests that mitochondrial transfer from MSCs is a novel strategy for the regeneration of various damaged cells via the rescue of their respiratory activities. This study is aimed at reviewing the functions of MSCs and the related roles of the programmed cell death of MSCs, including autophagy, apoptosis, pyroptosis, and ferroptosis, as well as the regulatory pathogenic mechanisms of MSCs in liver fibrosis. Research has demonstrated that the miR-200B-3p gene is differentially expressed gene between LF and normal liver samples, and that the miR-200B-3p gene expression is positively correlated with the degree of liver fibrosis, suggesting that MSCs could inhibit liver fibrosis through pyroptosis. It was confirmed that circulating monocytes could deliver MSC-derived immunomodulatory molecules to different sites by phagocytosis of apoptotic MSCs, thereby achieving systemic immunosuppression. Accordingly, it was suggested that characterization of the programmed cell death-mediated immunomodulatory signaling pathways in MSCs should be a focus of research.

Human stem cells for decompensated cirrhosis in adults

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the benefits and harms of stem cell treatment in adults with decompensated cirrhosis, regardless of ethnicity, sex, types of stem cells, route of stem cell injection, and administered dose.

Therapeutic effect of autologous bone marrow cells injected into the liver under the guidance of B‑ultrasound in the treatment of HBV‑related decompensated liver cirrhosis

The 5-year mortality rates associated with decompensated liver cirrhosis (DLC) can reach 50%, which suggests that this condition poses a serious health risk. In previous studies conducted by our group, autologous bone marrow nucleated cells (ABMNCs) were used to treat HIV-positive patients with DLC through the right omental vein; however, trauma and poor compliance were encountered. In the present study, the percutaneous liver approach to inject ABMNCs under the guidance of B-ultrasound was employed for the treatment of DLC. A total of 108 patients with DLC were retrospectively divided into the routine drug treatment group (control group; 30 cases), the right omental vein infusion of ABMNCs group (observation group 1; 38 cases) and the B-ultrasound-guided liver injection of ABMNCs group (observation group 2; 40 cases). After treatment, the liver synthesis (prothrombin time, albumin and ascites) and secretion functions (total bilirubin) in observation groups 1 and 2 were significantly improved compared with those of the control group (P<0.01) and the bone marrow function was also significantly improved compared with that of the control group (P<0.01). While, the bone marrow function (white blood cell, platelet, and hemoglobin) in observation group 1 was significantly improved compared with that of observation group 2 at the end of treatment (P<0.01). After a 1-year follow-up, the case fatality rate was 2.5% (1/40) in observation group 2, which was significantly lower than the 20% fatality rate (6/30) recorded in the control group (P<0.05). The injection of ABMNCs into the liver under the guidance of B-ultrasound was significantly better than conventional drug therapy in treating DLC. This approach has obvious advantages such as no hospitalization, minimal trauma, rapid recovery and good compliance, all of which make it worthy of application in primary hospitals.

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.

Therapeutic effects of stem cells in different body systems, a novel method that is yet to gain trust: A comprehensive review

Stem cell therapy has been used to treat several types of diseases, and it is expected that its therapeutic uses shall increase as novel lines of evidence begin to appear. Furthermore, stem cells have the potential to make new tissues and organs. Thus, some scientists propose that organ transplantation will significantly rely on stem cell technology and organogenesis in the future. Stem cells and its robust potential to differentiate into specific types of cells and regenerate tissues and body organs, have been investigated by numerous clinician scientists and researchers for their therapeutic effects. Degenerative diseases in different organs have been the main target of stem cell therapy. Neurodegenerative diseases such as Alzheimer's, musculoskeletal diseases such as osteoarthritis, congenital cardiovascular diseases, and blood cell diseases such as leukemia are among the health conditions that have benefited from stem cell therapy advancements. One of the most challenging parts of the process of incorporating stem cells into clinical practice is controlling their division and differentiation potentials. Sometimes, their potential for  uncontrolled growth will make these cells tumorigenic. Another caveat in this process is the ability to control the differentiation process. While stem cells can easily differentiate into a wide variety of cells,  a paracrine effect controlled activity, being in an appropriate medium will cause abnormal differentiation leading to treatment failure. In this review, we aim to provide an overview of the therapeutic effects of stem cells in diseases of various organ systems. In order to advance this new treatment to its full potential, researchers should focus on establishing methods to control the differentiation process, while policymakers should take an active role in providing adequate facilities and equipment for these projects. Large population clinical trials are a necessary tool that will help build trust in this method. Moreover, improving social awareness about the advantages and adverse effects of stem cell therapy is required to develop a rational demand in the society, and consequently, healthcare systems should consider established stem cell-based therapeutic methods in their treatment algorithms.

Autologous Bone Marrow Cell Infusion for the Treatment of Decompensated Liver Cirrhosis Patients With Type 2 Diabetes Mellitus

This study aimed to indicate whether autologous bone marrow cell infusion (ABMI) via the right omental vein (ROV) could have a regulatory effect on decompensated liver cirrhosis (DLC) patients with type 2 diabetes mellitus (T2DM). For this purpose, 24 DLC patients with T2DM were divided into observation group (n=14) and control group (n=10). Patients in the observation group were given ABMI through the ROV and right omental artery (ROA), and cases in the control group received ABMI through the ROV. At 1, 3, 6, and 12months after ABMI, it was revealed that the prothrombin time, the total bilirubin levels, and the amount of ascites were significantly lower, while the serum albumin levels in the two groups were markedly higher compared with those before ABMI (p<0.01), and there was no significant difference between the two groups at each time point (p>0.05). The fasting blood glucose and glycosylated hemoglobin levels at 6 and 12months after ABMI in the two groups significantly decreased compared with those before ABMI (p<0.05 or p<0.01), while the decreased levels in the observation group were more obvious than those in the control group at each time point (p<0.01). The amount of insulin in the observation group at 3, 6, and 12months after ABMI was significantly less than that before ABMI in the control group (p<0.01). In summary, ABMI showed a significant therapeutic efficacy for DLC patients with T2DM through ROV and ROA.

The Application of Mesenchymal Stem Cells in the Treatment of Liver Diseases: Mechanism, Efficacy, and Safety Issues

Mesenchymal stem cell (MSC) transplantation is a novel treatment for liver diseases due to the roles of MSCs in regeneration, fibrosis inhibition and immune regulation. However, the mechanisms are still not completely understood. Despite the significant efficacy of MSC therapy in animal models and preliminary clinical trials, issues remain. The efficacy and safety of MSC-based therapy in the treatment of liver diseases remains a challenging issue that requires more investigation. This article reviews recent studies on the mechanisms of MSCs in liver diseases and the associated challenges and suggests potential future applications.

Autologous bone marrow cell transplantation in the treatment of HIV patients with compensated cirrhosis

Liver stem cell therapy is a promising tool to improve decompensated liver cirrhosis (DLC). Especially in patients infected with human immunodeficiency virus (HIV), the condition of the liver may be aggravated by antiretroviral therapy. A total of 21 patients diagnosed with DLC and HIV infection were divided into two groups as follows: those who received (combination therapy group, 14 patients) and those who did not receive (routine therapy group, 7 patients) bone marrow cell transplantation through the portal vein. Two patients died of surgery-related complications in the combination therapy group. The results showed that the survival rate was 85.7% in the combination therapy group after 2 years of follow-up, which was significantly higher than the 14.3% in the conventional therapy group (P<0.01). After treatment, the liver function score decreased significantly in the combination therapy group at 1 (t = 4.276, P = 0.000), 3 (t = 9.153, P = 0.000), and 12 (t = 13.536, P = 0.000) months, the levels of albumin were significantly increased, and the total bilirubin level and prothrombin time were significantly reduced or shortened as compared with the routine therapy group (P<0.05 or <0.01). The white blood cell count, hemoglobin, platelet count, and CD4+ and CD8+ levels were significantly higher in the combination therapy group at different time points as compared with the routine therapy group (P<0.05 or <0.01). In summary, the combination therapy is effective in HIV-infected patients with DLC and useful for the recovery of liver function and cellular immune function but may increase the risk of severe complications after surgery.

Enhanced PRL-1 expression in placenta-derived mesenchymal stem cells accelerates hepatic function via mitochondrial dynamics in a cirrhotic rat model

BACKGROUND

Placenta-derived mesenchymal stem cells (PD-MSCs) have been highlighted as an alternative cell therapy agent that has become a next-generation stem cell treatment. Phosphatase of regenerating liver-1 (PRL-1), an immediate early gene, plays a critical role during liver regeneration. Here, we generated enhanced PRL-1 in PD-MSCs (PD-MSCs^PRL-1, PRL-1+) using lentiviral and nonviral gene delivery systems and investigated mitochondrial functions by PD-MSC^PRL-1 transplantation for hepatic functions in a rat bile duct ligation (BDL) model.

METHODS

PD-MSCs^PRL-1 were generated by lentiviral and nonviral AMAXA gene delivery systems and analyzed for their characteristics and mitochondrial metabolic functions. Liver cirrhosis was induced in Sprague-Dawley (SD) rats using common BDL for 10 days. PKH67+ naïve and PD-MSCs^PRL-1 using a nonviral sysyem (2 × 10⁶ cells/animal) were intravenously administered into cirrhotic rats. The animals were sacrificed at 1, 2, 3, and 5 weeks after transplantation and engraftment of stem cells, and histopathological analysis and hepatic mitochondrial functions were performed.

RESULTS

PD-MSCs^PRL-1 were successfully generated using lentiviral and nonviral AMAXA systems and maintained characteristics similar to those of naïve cells. Compared with naïve cells, PD-MSCs^PRL-1 improved respirational metabolic states of mitochondria. In particular, mitochondria in PD-MSCs^PRL-1 generated by the nonviral AMAXA system showed a significant increase in the respirational metabolic state, including ATP production and mitochondrial biogenesis (*p < 0.05). Furthermore, transplantation of PD-MSCs^PRL-1 using a nonviral AMAXA system promoted engraftment into injured target liver tissues of a rat BDL cirrhotic model and enhanced the metabolism of mitochondria via increased mtDNA and ATP production, thereby improving therapeutic efficacy.

CONCLUSIONS

Our findings will further our understanding of the therapeutic mechanism of enhanced MSCs and provide useful data for the development of next-generation MSC-based cell therapy and therapeutic strategies for regenerative medicine in liver disease.

AntagomiR-199a Enhances the Liver Protective Effect of Hypoxia-Preconditioned BM-MSCs in a Rat Model of Reduced-Size Liver Transplantation

BACKGROUND

Reduced-size liver transplantation (LT) was invented to overcome the shortage of donor livers; however, it has proven to be more susceptible to ischemia-reperfusion injury. Bone marrow-derived mesenchymal stem cell infusion has been shown to be protective following LT. Optimization of MSC infusion has been performed, among which hypoxia preconditioning and miRNA modulation have shown promise. MiR-199a inhibition was reported to induce angioneogenesis; however, whether mir-199a inhibition enhances the protective effect of Bone marrow-derived mesenchymal stem cells in LT remains unknown. In this study, we combined antagomiR-199a with hypoxia-preconditioned MSC (H-MSC) infusion to discuss their effect and mechanism in a rat model of reduced-size LT.

METHODS

A reduced-size LT model was constructed and H-MSCs were intraportally injected during operation. AgomiR-199a and antagomir-199a were injected through the caudal vein once a day after LT. The level of apoptosis and proinflammatory cytokines were measured. An anti-vascular endothelial growth factor (VEGF) antibody was injected to further explore the underlying mechanism.

RESULTS

AntagomiR-199a plus H-MSC not only significantly decreased ALT and AST 72 h after LT but also ameliorated the level of apoptosis and inhibited inflammatory reactions. On the contrary, agomir-199a reduced the protective effect of the H-MSC infusion. In terms of mechanism, the liver protective effect of miR-199a inhibition was abolished by treatment with a VEGF-neutralizing antibody.

CONCLUSIONS

AntagomiR-199a enhanced the protective effect of H-MSCs infusion via activation of the hypoxia induction factor 1α/VEGF axis.

Locoregional delivery of stem cell-based therapies

Interventional regenerative medicine (IRM) uses image-guided, minimally invasive procedures for the targeted delivery of stem cell-based therapies to regenerate, replace, or repair damaged organs. Although many cellular therapies have shown promise in the preclinical setting, clinical results have been suboptimal. Most intravenously delivered cells become trapped in the lungs and reticuloendothelial system, resulting in little therapy reaching target tissues. IRM aims to increase the efficacy of cell-based therapies by locoregional stem cell delivery via endovascular, endoluminal, or direct injection into tissues. This review highlights routes of delivery, disease states, and mechanisms of action involved in the targeted delivery of stem cells.

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.

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.

Extracellular vesicles derived from human embryonic stem cell‐MSCs ameliorate cirrhosis in thioacetamide‐induced chronic liver injury

Various somatic tissue‐derived mesenchymal stromal cells (MSCs) have been considered as an attractive therapeutic tool for treatment of liver diseases in which the secretion of soluble factors or extracellular vesicles (EVs) is the most probable mechanism. The experimental application of human embryonic stem cell‐derived MSC (ES‐MSC) increased rapidly and showed promising results, in vitro and in vivo. However, possible therapeutic effects of human ES‐MSC and their EVs on Thioacetamide (TAA)‐induced chronic liver injury have not been evaluated yet. Our data indicated that human ES‐MSC can significantly suppress the proliferation of peripheral blood mononuclear cells compared to bone marrow (BM)‐MSC and adipose (AD)‐MSC. Moreover, ES‐MSC increased the secretion of anti‐inflammatory cytokines (i.e., TGF‐β and IL‐10) and decreased IFN‐γ, compared to other MSCs. ES‐MSC EVs demonstrated immunomodulatory activities comparable to parental cells and ameliorated cirrhosis in TAA‐induced chronic rat liver injury, that is, reduction in fibrosis and collagen density, necrosis, caspase density, portal vein diameter, and transaminitis. The gene expression analyses also showed upregulation in collagenases (MMP9 and MMP13), anti‐apoptotic gene (BCL‐2) and anti‐inflammatory cytokines (TGF‐β1 and IL‐10) and down‐regulation of major contributors to fibrosis (Col1α, αSMA, and TIMP1), pro‐apoptotic gene (BAX) and pro‐inflammatory cytokines (TNFα and IL‐2) following treatment with ES‐MSC and ES‐MSC‐EV. These results demonstrated that human ES‐MSC and ES‐MSC EV as an off‐the‐shelf product, that needs further assessment to be suggested as an allogeneic product for therapeutic applications for liver fibrosis.

Therapeutic efficacy and safety of umbilical cord mesenchymal stem cell transplantation for liver cirrhosis in Chinese population: A meta-analysis

BACKGROUND AND OBJECTIVE

Mesenchymal stem cells transfusion has been considered as a promising option for liver cirrhosis (LC). The aim of this study was to systematically evaluate the efficacy and safety of umbilical cord mesenchymal stem cells (UMSC) combined with traditional supportive therapy (TST) for the treatment of patients with LC.

METHODS

Data was extracted from clinical trials published on Web of Science, PubMed, EMBASE, Cochrane Library, Wanfang and CNKI database. The evaluated outcome measurements included liver function, coagulation function, liver fibrosis indexes, clinical symptoms, quality of life (QOL) and adverse events.

RESULTS

A total of 14 trials including 717 LC patients met our selection criteria were involved. The liver function of LC patients was significantly improved after combined therapy (UMSC plus TST), indicated by decreased total bilirubin, alanine aminotransferase and prothrombin time, and increased serum albumin, cholinesterase and prothrombin activity. The QOL of patients was also improved after UMSC therapy. Compared with TST alone, the combined therapy showed better treatment effect based on measurements of hyaluronic acid (OR=-143.20, CI=-181.58 to -104.82, P<0.00001), laminin (OR=-50.65, CI=-53.70 to -47.61, P<0.00001), type III procollagen (OR=-8.68, CI=-9.00 to -8.36, P<0.00001), type IV collagen (OR=-105.79, CI=-132.44 to -79.14, P<0.00001) and plasma prolidase (OR=-876.54, CI=-911.89 to -840.56, P<0.00001). Moreover, the patients' clinical symptoms including fatigue (4th, P=0.003; 8th, P=0.01), appetite (4th, P<0.0001; 8th, P=0.06), ascites (4th, P=0.03; 8th, P=0.17), and abdominal distension (4th, P=0.0008; 8th, P=0.64) were also improved in patients treated by combined therapy without adverse events observed.

CONCLUSION

UMSC and TST combined therapy for LC patients improved their liver function, clinical symptoms and QOL without severe adverse events, therefore is safe and effective in LC therapy.

A pooled analysis of mesenchymal stem cell-based therapy for liver disease

BACKGROUND

Liver disease is a major cause of death and disability. Mesenchymal stem cells (MSCs) show promise for the treatment of liver disease. However, whether MSC-based therapy is more effective than conventional treatment is unclear, as are the optimal MSC source, the administration frequency, and the most effective MSC delivery route. We therefore undertook a systematic review and meta-analysis of the therapeutic efficacy of MSCs against liver disease and the related factors.

METHODS

We systematically searched Medline (PubMed), Cochrane Library, EMBASE, ClinicalTrials.gov, and SinoMed CBM to identify studies published up to June 2017 involving liver disease patients receiving MSC-based therapy and which reported estimates of liver function during the follow-up period.

RESULTS

Thirty-nine studies were selected from 672 publications. According to a meta-analysis of 23 controlled studies, compared with conventional treatment MSC therapy significantly improves liver function in patients with liver disease in terms of the model of end-stage liver disease score, albumin, alanine aminotransferase, and total bilirubin levels, and prothrombin time, up to 6 months after administration. However, it has no beneficial effects in terms of prothrombin activity, international normalized ratio, or cholinesterase level. Considerable heterogeneity was identified at most time points. Subgroup analyses showed that a single MSC injection was more effective than multiple injections, MSC administration was more effective via the hepatic artery than the peripheral vein, and MSCs derived from bone marrow were more effective than those derived from the umbilical cord.

CONCLUSIONS

MSC-based therapy is relatively safe and improves liver function during the first 6 months after administration. A single injection administration via the hepatic artery and MSCs derived from bone marrow are optimal in terms of improving liver function. However the significant heterogeneity among studies and discontinuous results of the subgroup meta-analysis should be addressed; moreover the long-term efficacy of MSC therapy warrants further investigation.

Umbilical cord blood stem cells transplantation as an adjunctive treatment strategy for liver cirrhosis in Chinese population: a meta-analysis of effectiveness and safety

Objective

The aim of the study was to evaluate the efficacy and safety of umbilical cord blood stem cells (USCs) transplantation combined with routine supportive therapy (RST) for liver cirrhosis (LC).

Materials and methods

Clinical trials involved in this research were searched from Web of Science, PubMed, EMBASE, Cochrane Library, Wanfang and CNKI database. Treatment effects, quality of life (QoL), adverse events and other outcome measures were extracted and evaluated.

Results

A total of 10 trials including 616 LC patients were involved in this study. Based on our analysis, the liver function of LC patients was significantly improved after USCs transplantation and RST combined therapy, indicated by decreased total bilirubin, alanine aminotransferase, aspartate aminotransferase levels and prothrombin time and increased serum albumin level and prothrombin activity. Compared to those treated by RST alone, patients treated by combined therapy showed more satisfied treatment effects, improved QoL reflected by improved appetite (odds ratio [OR]=5.43, 95% CI=2.84 to 10.38, P<0.00001) and relieved fatigue (OR=4.33, 95% CI=0.87 to 21.60, P=0.07), ascetic fluid (OR=4.56, 95% CI=2.69 to 7.74, P<0.00001), abdominal distension (OR=4.01, 95% CI=1.34 to 12.02, P=0.01) and edema (OR=2.69, 95% CI=0.23 to 31.72, P=0.43). No serious adverse events occurred during USCs therapy.

Conclusion

USCs transplantation is a safe and effective adjuvant therapy for RST-treated LC, possibly through improving patients’ liver function.

Historical Perspectives and Advances in Mesenchymal Stem Cell Research for the Treatment of Liver Diseases

Liver transplantation is the only effective therapy for patients with decompensated cirrhosis and fulminant liver failure. However, due to a shortage of donor livers and complications associated with immune suppression, there is an urgent need for new therapeutic strategies for patients with end-stage liver diseases. Given their unique function in self-renewal and differentiation potential, stem cells might be used to regenerate damaged liver tissue. Recent studies have shown that stem cell-based therapies can improve liver function in a mouse model of hepatic failure. Moreover, acellular liver scaffolds seeded with hepatocytes produced functional bioengineered livers for organ transplantation in preclinical studies. The therapeutic potential of stem cells or their differentiated progenies will depend on their capacity to differentiate into mature and functional cell types after transplantation. It will also be important to devise methods to overcome their genomic instability, immune reactivity, and tumorigenic potential. We review directions and advances in the use of mesenchymal stem cells and their derived hepatocytes for liver regeneration. We also discuss the potential applications of hepatocytes derived from human pluripotent stem cells and challenges to using these cells in treating end-stage liver disease.

Mesenchymal stem cell therapy for advanced liver cirrhosis: A case report

Mesenchymal stem cell (MSC) transplant may offer an alternative to liver transplantation in patients with end‐stage liver disease. However, its efficacy remains uncertain. MSC was performed on a 50‐year‐old male with decompensated (Child‐Turcotte‐Pugh grade C) alcoholic liver cirrhosis due to an absence of donors for adult‐deceased and living‐related liver transplantation. Autologous bone marrow‐derived MSCs were harvested from the patient and cultured using standard protocols. The MSCs were subsequently re‐administrated into the liver via hepatic intra‐arterial infusion on two separate occasions. After infusion, there was an improvement in biochemical parameters (serum total bilirubin, serum albumin), and a reduction of diuretic use for ascites for up to 8 weeks. However, all biochemical and clinical parameters deteriorated on long‐term follow‐up without any further infusions. The patient eventually succumbed to his disease. MSC transplantation may have a clinical benefit on adult patients with end‐stage liver cirrhosis, but this appears to be transitory.

Molecular Imaging of Stem Cell Transplantation for Liver Diseases: Monitoring, Clinical Translation, and Theranostics

Stem cell transplantation has been investigated to rescue experimental liver failure and is promising to offer an alternative therapy to liver transplantation for liver diseases treatment. Several clinical studies in this field have been carried out, but the therapeutic benefit of this treatment is still controversial. A major obstacle to developing stem cell therapies in clinic is being able to visualize the cells in vivo. Imaging modalities allow optimization of delivery, detecting cell survival and functionality by in vivo monitoring these transplanted graft cells. Moreover, theranostic imaging is a brand new field that utilizes nanometer-scale materials to glean diagnostic insight for simultaneous treatment, which is very promising to improve stem cell-based therapy for treatment of liver diseases. The aim of this review was to summarize the various imaging tools that have been explored with advanced molecular imaging probes. We also outline some recent progress of preclinical and clinical studies of liver stem cells transplantation. Finally, we discuss theranostic imaging for stem cells transplantation for liver dysfunction and future opportunities afforded by theranostic imaging.

Intraportal mesenchymal stem cell transplantation prevents acute liver failure through promoting cell proliferation and inhibiting apoptosis

BACKGROUND

Transplantation of mesenchymal stem cells (MSCs) has been regarded as a potential treatment for acute liver failure (ALF), but the optimal route was unknown. The present study aimed to explore the most effective MSCs transplantation route in a swine ALF model.

METHODS

The swine ALF model induced by intravenous injection of D-Gal was treated by the transplantation of swine MSCs through four routes including intraportal injection (InP group), hepatic intra-arterial injection (AH group), peripheral intravenous injection (PV group) and intrahepatic injection (IH group). The living conditions and survival time were recorded. Blood samples before and after MSCs transplantation were collected for the analysis of hepatic function. The histology of liver injury was interpreted and scored in terminal samples. Hepatic apoptosis was detected by TUNEL assay. Apoptosis and proliferation related protein expressions including cleaved caspase-3, survivin, AKT, phospho-AKT (Ser473), ERK and phospho-ERK (Tyr204) were analyzed by Western blotting.

RESULTS

The average survival time of each group was 10.7+/-1.6 days (InP), 6.0+/-0.9 days (AH), 4.7+/-1.4 days (PV), 4.3+/-0.8 days (IH), respectively, when compared with the average survival time of 3.8+/-0.8 days in the D-Gal group. The survival rates between the InP group and D-Gal group revealed a statistically significant difference (P<0.01). Pathological and biochemical analysis showed that liver damage was the worst in the D-Gal group, while less injury in the InP group. Histopathological scores revealed a significant decrease in the InP group (3.17+/-1.04, P<0.01) and AH group (8.17+/-0.76, P<0.05) as compared with that in the D-Gal group (11.50+/-1.32). The apoptosis rate in the InP group (25.0%+/-3.4%, P<0.01) and AH group (40.5%+/-1.0%, P<0.05) was lower than that in the D-Gal group (70.6%+/-8.5%). The expression of active caspase-3 was inhibited, while the expression of survivin, AKT, phospho-AKT (Ser473), ERK and phospho-ERK (Tyr204) was elevated in the InP group.

CONCLUSIONS

Intraportal injection was superior to other pathways for MSC transplantation. Intraportal MSC transplantation could improve liver function, inhibit apoptosis and prolong the survival time of swine with ALF. The transplanted MSCs may participate in liver regeneration via promoting cell proliferation and suppressing apoptosis during the initial stage of ALF.

Clinical effectiveness of cell therapies in patients with chronic liver disease and acute-on-chronic liver failure: a systematic review protocol

BACKGROUND

Chronic liver disease (CLD) is a major health burden worldwide. Liver cirrhosis, a form of CLD is the fifth most common cause of death in the UK. Acute-on-chronic liver failure (ACLF) is the result of an acute insult superimposed on patients with liver cirrhosis as a result of precipitating events such as infection or bleeding. ACLF has a high associated mortality as a result of multi-organ failure. The only effective treatment for CLD is liver transplantation, but the treatment is limited by shortage of donor organs. As a result, alternative treatments such as cell therapies have been studied in patients with liver diseases. This study will systematically review the evidence on clinical effectiveness of cell therapies in patients.

METHODS

All types of study design that investigate the effectiveness of cell therapies (haematopoietic, mesenchymal and unsorted cell types) of autologous or allogeneic origin and/or the use of granulocyte colony-stimulating factor in patients with CLD including ACLF will be included (except case reports). Both autologous and allogenic cell types will be included. The primary outcomes of interest are survival, model for end-stage liver disease score, quality of life and adverse events. Secondary outcomes include liver function tests, Child-Pugh score and events of liver decompensation. A literature search will be conducted in the following databases: MEDLINE, MEDLINE in Process, EMBASE and Cochrane Library (CENTRAL, CDSR, DARE, HTA databases). Trial registers will be searched for ongoing trials, as will conference proceedings. Reference lists of relevant articles and systematic reviews will be screened. Randomised controlled trial (RCT) evidence is likely to be scant; therefore, controlled trials and concurrently controlled observational studies will be primarily analysed and uncontrolled observational studies will be analysed where primary outcomes are not reported in the control studies or where uncontrolled studies have longer follow-up. Initial screening of studies will be carried by one reviewer with a proportion checked by another reviewer. Full-text selection will be performed by two reviewers independently against the pre-defined selection criteria. The data collection and the risk of bias assessment will be completed by one reviewer and counter checked by another reviewer for all selected studies. Where appropriate, data will be meta-analysed for each study design, therapy and outcome. Data specifically on ACLF will be treated as a subgroup.

DISCUSSION

This systematic review will identify the available evidence on the effectiveness of cell therapies in patients with CLD and in ACLF subgroup. The findings will aid decision-making by clinicians and health service leaders.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016016104.

Cell therapy in chronic liver disease

PURPOSE OF REVIEW

To date, the only curative treatment for end-stage liver disease is liver transplantation, which is limited by the shortage of available organs. Cell therapy, in the form of cell transplantation or cell-based extracorporeal support devices, may in the future offer an alternative to transplantation, or at least provide liver function support as a bridging therapy until surgery may be performed. The purpose of this review is to highlight the most recent advances made in the field of cell therapy and regenerative medicine for the treatment of chronic liver disease.

RECENT FINDINGS

After hepatocyte transplantation, long-term engraftment in the liver and spleen may be achieved, which can be stimulated through preconditioning, multiple infusions, and inflammatory response blockade. Mesenchymal stem cells are promising candidates for cell transplantation, as they have been shown to reduce liver fibrosis and support endogenous regeneration. Adipose tissue-derived stem cells are also being tested in this setting, because of their ready availability. Bioartificial liver devices are being built that allow for effective preservation of hepatocytes, and one such device has recently demonstrated survival benefit in a porcine model of liver failure.

SUMMARY

Cell transplantation of primary hepatocytes or stem cell-derived hepatocyte-like cells for the treatment of chronic liver disease holds promise. Bioartificial liver systems may in the future be able to bridge acute-on-chronic liver failure patients to liver transplantation.

Combined mesenchymal stem cell transplantation and interleukin-1 receptor antagonism after partial hepatectomy

AIM

To study the therapeutic effects of mesenchymal stem cells (MSCs) and an interleukin-1 receptor antagonist (IL-1Ra) in acute liver failure.

METHODS

Chinese experimental miniature swine (15 ± 3 kg, 5-8 mo) were obtained from the Laboratory Animal Centre of the Affiliated Drum Tower Hospital of Nanjing University Medical School. Acute liver failure was induced via 85% hepatectomy, and animals were treated by MSC transplantation combined with IL-1Ra injection. Blood samples were collected for hepatic function analysis, and the living conditions and survival time were recorded. Liver injury was histologically analyzed. Hepatic cell regeneration and apoptosis were studied by Ki67 immunohistochemistry and terminal deoxynucleotidyl transferase dUTP nick end labeling, respectively. The levels of protein kinase B and nuclear factor-κB expression were analyzed by Western blotting.

RESULTS

MSCs were infected with a lentivirus for expression of green fluorescent protein (GFP) for subsequent identification; 97.3% of the MSCs were positive for GFP as assessed by flow cytometry. Additional flow cytometric analysis of cell surface marker expression demonstrated that > 90% of GFP-expressing MSCs were also positive for CD29, CD44, and CD90, indicating that most of these cells expressed typical markers of MSCs, and the population of MSCs was almost pure. Transplantation of MSCs in combination with 2 mg/kg IL-1Ra therapy significantly improved survival time compared to the acute liver failure model group (35.3 ± 6.7 d vs 17.3 ± 5.5 d, P < 0.05). Combined therapy also promoted improvement in serum inflammatory cytokines and biochemical conditions. The observed hepatic histopathologic score was significantly lower in the group with combined therapy than in the model group (3.50 ± 0.87 vs 8.17 ± 1.26, P < 0.01). In addition, liver cell apoptosis in the combined therapy group was significantly inhibited (18.1 ± 2.1% vs 70.8 ± 3.7%, P < 0.01), and hepatic cell regeneration increased. A significant increase in protein kinase B expression and decrease in nuclear factor-κB expression were observed (P < 0.01), which supports their important roles in liver regeneration.

CONCLUSION

MSCs and IL-1Ra had a synergistic effect in liver regeneration via regulation of inflammation and apoptotic signaling.

Comparison of the Treatment Efficiency of Bone Marrow-Derived Mesenchymal Stem Cell Transplantation via Tail and Portal Veins in CCl4-Induced Mouse Liver Fibrosis

Because of self-renewal, strong proliferation in vitro, abundant sources for isolation, and a high differentiation capacity, mesenchymal stem cells are suggested to be potentially therapeutic for liver fibrosis/cirrhosis. In this study, we evaluated the treatment effects of mouse bone marrow-derived mesenchymal stem cells (BM-MSCs) on mouse liver cirrhosis induced by carbon tetrachloride. Portal and tail vein transplantations were examined to evaluate the effects of different injection routes on the liver cirrhosis model at 21 days after transplantation. BM-MSCs transplantation reduced aspartate aminotransferase/alanine aminotransferase levels at 21 days after injection. Furthermore, BM-MSCs induced positive changes in serum bilirubin and albumin and downregulated expression of integrins (600- to 7000-fold), transforming growth factor, and procollagen-α1 compared with the control group. Interestingly, both injection routes ameliorated inflammation and liver cirrhosis scores. All mice in treatment groups had reduced inflammation scores and no cirrhosis. In conclusion, transplantation of BM-MSCs via tail or portal veins ameliorates liver cirrhosis in mice. Notably, there were no differences in treatment effects between tail and portal vein administrations. In consideration of safety, we suggest transfusion of bone marrow-derived mesenchymal stem cells via a peripheral vein as a potential method for liver fibrosis treatment.

The impact of repeated autologous infusion of haematopoietic stem cells in patients with liver insufficiency

INTRODUCTION

The worldwide shortage of donor livers has prompted the search for alternative cell therapies. Previous data from our laboratory proved a supportive role for stem cell therapy in the treatment of end-stage liver disease patients. Therefore; this study was conducted to assess the clinical and biochemical effects of repeated stem cell infusion.

METHODS

Ninety patients with liver cirrhosis were randomized to receive either one session treatment (G-I) or two sessions 4 months apart (G-II) of autologous haematopoietic stem cells (HSCs) transplantation and a control group (G-III) who received regular liver treatment. G-CSF was administered to transplanted patients before infusion; HSCs were isolated from 400 cc bone marrow (BM) aspirate. CD34+/CD133+ cells were purified: 50 % of the cells were infused locally in the portal vein on the same day and the other 50 % were differentiated to MSC and infused systemically in a peripheral vein (one session treatment G-I). In G-II, the same process was repeated after 4 months from the first treatment (two session's treatment G-II). Liver function was monitored for 12 months after stem cell therapy (SCT).

RESULTS

Statistically significant improvement was reported in the transplanted patients (G-1) as regards the mean serum albumin, bilirubin and INR levels which started to improve after 2 weeks of treatment and continued to improve till the 6(th) month in the single infusion group. The two sessions infused group (G-II) showed sustained response which continued throughout the all follow-up period (12 month). By the end of the study, 36.7 % of the patients in G-I and 66.7 % in G-II showed improvement in the degree of ascites compared to the control group (G-III). We also reported an improvement in the hepatic functional reserve as assessed by the Child-Pugh and MELD score. Safety of the procedure was evidenced by the low incidence of complications encountered.

CONCLUSION

In patients with end-stage liver disease, the repeated infusion with combined routes portal and peripheral veins has a beneficial effect on liver functions with minimal adverse events and more lasting clinical efficacy after repeated HSCs infusion.

Transplantation of autologous mesenchymal stem cells for end-stage liver cirrhosis: a meta-analysis based on seven controlled trials

Background. The bone marrow-derived mesenchymal stem cells (BM-MSCs) have demonstrated great potential as regenerative medicine in different therapeutic applications. This study aims to pool previous controlled clinical trials to make an update assessment of the effectiveness of BM-MSC transplantation on end-stage liver cirrhosis. Methods. Relevant studies published between January 1990 and June 2014 were searched among Pubmed, Embase, and ClinicalTrial.gov. A meta-analysis was performed to assess the effect of BM-MSCs on liver function indicators, including Models of End-Stage Liver Disease (MELD) score, serum albumin (g/L), total bilirubin (mg/dl), Prothrombin concentration (%), and alanine aminotransferase (ALT) (U/L). Results. BM-MSCs therapy could significantly improve liver function in patients with end-stage liver cirrhosis, in terms of MELD score, serum albumin, total bilirubin, and prothrombin concentration, at least during the half year after transplantation. Conclusions. Due to BM-MSCs' immunomodulatory functions and the potential to differentiate into hepatocytes, they are a promising therapeutic agent to liver cirrhosis. Considering currently available evidence, this therapy is relatively safe and effective in improving liver function. However, how different variables should be controlled to optimize the therapeutic effect is still not clear. Thus, future mechanism studies and clinical trials are required for this optimization.