Deficient proliferation of bone marrow-derived mesenchymal stem cells in patients with chronic hepatitis B viral infections and cirrhosis of the liver

Stem cell therapy in coronavirus disease 2019: current evidence and future potential

The end of 2019 saw the beginning of the coronavirus disease 2019 (COVID-19) pandemic that soared in 2020, affecting 215 countries worldwide, with no signs of abating. In an effort to contain the spread of the disease and treat the infected, researchers are racing against several odds to find an effective solution. The unavailability of timely and affordable or definitive treatment has caused significant morbidity and mortality. Acute respiratory distress syndrome (ARDS) caused by an unregulated host inflammatory response toward the viral infection, followed by multi-organ dysfunction or failure, is one of the primary causes of death in severe cases of COVID-19 infection. Currently, empirical management of respiratory and hematological manifestations along with anti-viral agents is being used to treat the infection. The quest is on for both a vaccine and a more definitive management protocol to curtail the spread. Researchers and clinicians are also exploring the possibility of using cell therapy for severe cases of COVID-19 with ARDS. Mesenchymal stromal cells are known to have immunomodulatory properties and have previously been used to treat viral infections. This review explores the potential of mesenchymal stromal cells as cell therapy for ARDS.

Molecular Mechanisms Responsible for Mesenchymal Stem Cell-Based Treatment of Viral Diseases

Mesenchymal stem cells (MSCs) are adult, immunomodulatory stem cells which reside in almost all postnatal tissues. Viral antigens and damage-associated molecular patterns released from injured and infected cells activate MSCs, which elicit strong antiviral immune response. MSC-sourced interferons and inflammatory cytokines modulate the cytotoxicity of NK cells and CTLs, enhance the antigen-presentation properties of DCs and macrophages, regulate cytokine synthesis in CD4+ T helper cells and promote antibody production in B cells. After the elimination of viral pathogens, MSCs produce immunoregulatory cytokines and trophic factors, prevent the over-activation of immune cells and promote tissue repair and regeneration. In this review article, we summarize the current knowledge on the molecular mechanisms that are responsible for the MSC-dependent elimination of virus-infected cells, and we emphasize the therapeutic potential of MSCs and their secretomes in the treatment of viral diseases.

Bone marrow-derived mesenchymal stem cells utilize the notch signaling pathway to induce apoptosis of hepatic stellate cells via NF-κB sensor

The present study aimed at evaluating the mechanism by which functionality of hepatic stellate cells (HSCs) is modulated by bone marrow stromal cells (BMSCs). Induction of apoptosis in HSCs was found to be caused by directly co-culturing HSCs with BMSCs, where the expression of α-smooth muscle actin (α-SMA) increased significantly in HSCs, along with an increase in their proliferation rate. Additionally, expression of Hes1 and Notch1 in HSCs co-cultured with BMSCs increased significantly at both protein and mRNA levels. Blocking of the notch signaling pathway (NSP) either by Notch1 siRNA or by DAPT treatment increased the proliferation rate while decreasing apoptosis and led to activation of the NF-κB signaling pathway in HSCs co-cultured with BMSCs. These effects were found to be reversed in HSCs overexpressing IκB S32/S36 mutants. The Notch signaling-mediated cell-cell contact was partially involved in the significant inhibition of proliferation of HSCs by BMSCs. Additionally, the NF-κB pathway was found to be responsible for NSP-mediated inhibition of growth of HSCs in the co-culture system. Thus, BMSCs might have a potential therapeutic significance in treating hepatic fibrosis.

Anti-fibrotic mechanisms of exogenously-expanded mesenchymal stromal cells for fibrotic diseases

Most chronic diseases involving inflammation have a fibrotic component that involves remodeling and excess accumulation of extracellular matrix components. Left unchecked, fibrosis leads to organ failure and death. Mesenchymal stromal cells (MSCs) are emerging as a potent cell-based therapy for a wide spectrum of fibrotic conditions due to their immunomodulatory, anti-inflammatory and anti-fibrotic properties. This review provides an overview of known mechanisms by which MSCs mediate their anti-fibrotic actions and in relation to animal models of pulmonary, liver, renal and cardiac fibrosis. Recent MSC clinical trials results in liver, lung, skin, kidney and hearts are discussed and next steps for future MSC-based therapies including pre-activated or genetically-modified cells, or extracellular vesicles are also considered.

Transplantation with GXHPC1 for Liver Cirrhosis: Phase 1 Trial

Currently, the only effective therapy for cirrhosis of the liver is liver transplantation. However, finding a compatible liver is difficult due to the low supply of healthy livers and the ever-increasing demand. However, stem-cell therapy may offer a solution for liver cirrhosis; for example, GXHPC1 therapy preparation contains adipose-derived mesenchymal stem cells (AD-MSCs) and was developed for the treatment of liver cirrhosis. In our previous report, animal studies suggested that treatment of a diseased liver via GXHPC1 transplantation can abrogate liver fibrosis and facilitate recovery of liver function. In our current human trial, patients with liver cirrhosis were included. Their adipose tissue was harvested from the subcutaneous fat of the abdominal wall during surgery. AD-MSCs were cultured and suspended at a concentration of 100 million cells in 1 ml of physiological saline (i.e., GXHPC1). This human study passed the Taiwan Food and Drug Administration IND inspection and received Phase I clinical trial permission. The trial was conducted with six patients with liver cirrhosis to demonstrate the safety and efficacy of administering GXHPC1. Intrahepatic injection of GXHPC1 did not cause any safety issues in the analysis of adverse drug reactions and suspected unexpected serious adverse reactions, and showed a tendency for improvement of liver function, METAVIR score, Child–Pugh score, MELD score, and quality of life for patients with liver cirrhosis.

A Pilot Study of Mesenchymal Stem Cell Therapy for Acute Liver Allograft Rejection

Acute allograft rejection remains common after liver transplantation despite modern immunosuppressive agents. In addition, the long-term side effects of these regimens, including opportunistic infections, are challenging. This study evaluated the safety and clinical feasibility of umbilical cord-derived mesenchymal stem cell (UC-MSC) therapy in liver transplant patients with acute graft rejection. Twenty-seven liver allograft recipients with acute rejection were randomly assigned into the UC-MSC infusion group or the control group. Thirteen patients received one infusion of UC-MSCs (1 × 10⁶ /kg body weight); one patient received multiple UC-MSC infusions; 13 patients were used as controls. All enrolled patients received conventional immunosuppressive agents with follow-up for 12 weeks after UC-MSC infusions. No side effects occurred in treated patients. Four weeks after UC-MSC infusions, alanine aminotransferase levels had decreased markedly and remained lower throughout the 12-week follow-up period. Importantly, allograft histology was improved after administration of UC-MSCs. The percentage of regulatory T cells (Tregs) and the Treg/T helper 17 (Th17) cell ratio were significantly increased 4 weeks after infusions; in contrast, the percentage of Th17 cells showed a decreasing trend. In controls, the percentages of Tregs and Th17 cells and the Treg/Th17 ratio were statistically unchanged from the baseline measurements. Transforming growth factor beta 1 and prostaglandin E2 were increased significantly after UC-MSC infusions; by contrast, there were no significant changes in controls. Our data suggest that UC-MSC infusion for acute graft rejection following liver transplantation is feasible and may mediate a therapeutic immunosuppressive effect. Stem Cells Translational Medicine 2017;6:2053-2061.

Suppression of tumor cell proliferation and migration by human umbilical cord mesenchymal stem cells: A possible role for apoptosis and Wnt signaling

Human umbilical cord-derived mesenchymal stem cells (hUCMSCs) represent potential therapeutic tools for solid tumors. However, there are numerous inconsistent results regarding the effects of hUCMSCs on tumors, and the mechanisms underlying this remain poorly understood. The present study further examined this controversial issue by analyzing the molecular mechanisms of the inhibitory effects of hUCMSCs on the proliferation and migration of the human lung cancer A549 cell line and the human hepatocellular carcinoma (HCC) BEL7402 cell line in vitro. Flow cytometric analysis demonstrated that hUCMSCs arrested tumor cells in specific phases of the cell cycle and induced the apoptosis of tumor cells by using the hUCMSC-conditioned medium (hUCMSC-CM). The hUCMSC-CM also attenuated the migratory abilities of the two tumor cell types. Furthermore, the expression of B-cell lymphoma 2 (Bcl-2), the pro-form of caspase-7 (pro-caspase-7), β-catenin and c-Myc was downregulated, while that of ephrin receptor (EphA5), a biomarker of cancer cell dormancy, was slightly increased in these two tumor cell lines treated with hUCMSC-CM. Specifically, when co-cultured via direct cell-to-cell contact, hUCMSCs were able to spontaneously fuse with any of the two types of solid tumor cells. These observations suggested that hUCMSCs may be a promising candidate for the biological therapy of lung cancer and HCC. Future studies should focus on detailed evidence for cell fusion, as well as other mechanisms proposed in the present study, by introducing additional experimental approaches and models.

Induction of hepatocyte-like cells from human umbilical cord-derived mesenchymal stem cells by defined microRNAs

Generating functional hepatocyte‐like cells (HLCs) from mesenchymal stem cells (MSCs) is of great urgency for bio‐artificial liver support system (BALSS). Previously, we obtained HLCs from human umbilical cord‐derived MSCs by overexpressing seven microRNAs (HLC‐7) and characterized their liver functions in vitro and in vivo. Here, we aimed to screen out the optimal miRNA candidates for hepatic differentiation. We sequentially removed individual miRNAs from the pool and examined the effect of transfection with remainder using RT‐PCR, periodic acid—Schiff (PAS) staining and low‐density lipoprotein (LDL) uptake assays and by assessing their function in liver injury models. Surprisingly, miR‐30a and miR‐1290 were dispensable for hepatic differentiation. The remaining five miRNAs (miR‐122, miR‐148a, miR‐424, miR‐542‐5p and miR‐1246) are essential for this process, because omitting any one from the five‐miRNA combination prevented hepatic trans‐differentiation. We found that HLCs trans‐differentiated from five microRNAs (HLC‐5) expressed high level of hepatic markers and functioned similar to hepatocytes. Intravenous transplantation of HLC‐5 into nude mice with CCl₄‐induced fulminant liver failure and acute liver injury not only improved serum parameters and their liver histology, but also improved survival rate of mice in severe hepatic failure. These data indicated that HLC‐5 functioned similar to HLC‐7 in vitro and in vivo, which have been shown to resemble hepatocytes. Instead of using seven‐miRNA combination, a simplified five‐miRNA combination can be used to obtain functional HLCs in only 7 days. Our study demonstrated an optimized and efficient method for generating functional MSC‐derived HLCs that may serve as an attractive cell alternative for BALSS.

Mesenchymal Stromal Cells and Viral Infection

Mesenchymal Stromal Cells (MSCs) are a subset of nonhematopoietic adult stem cells, readily isolated from various tissues and easily culture-expanded ex vivo. Intensive studies of the immune modulation and tissue regeneration over the past few years have demonstrated the great potential of MSCs for the prevention and treatment of steroid-resistant acute graft-versus-host disease (GvHD), immune-related disorders, and viral diseases. In immunocompromised individuals, the immunomodulatory activities of MSCs have raised safety concerns regarding the greater risk of primary viral infection and viral reactivation, which is a major cause of mortality after allogeneic transplantation. Moreover, high susceptibilities of MSCs to viral infections in vitro could reflect the destructive outcomes that might impair the clinical efficacy of MSCs infusion. However, the interplay between MSCs and virus is like a double-edge sword, and it also provides beneficial effects such as allowing the proliferation and function of antiviral specific effector cells instead of suppressing them, serving as an ideal tool for study of viral pathogenesis, and protecting hosts against viral challenge by using the antimicrobial activity. Here, we therefore review favorable and unfavorable consequences of MSCs and virus interaction with the highlight of safety and efficacy for applying MSCs as cell therapy.

Human umbilical cord mesenchymal stem cells: an overview of their potential in cell-based therapy

INTRODUCTION

Human umbilical cord mesenchymal stem cells (HUC-MSCs) are one of the typical adult stem cells; they have superiorities including low immunogenicity, non-invasive harvest procedure, easy expansion in vitro, and ethical access compared with stem cells from other sources. Therefore, HUC-MSCs are a promising candidate for cell-based therapy.

AREAS COVERED

Here we reviewed the development of stem cell-based therapy, the manufacturing and banking process of HUC-MSCs, the emerging clinical studies in the field of cancer, central nervous system diseases, liver diseases and graft-versus-host disease, the potential therapeutic mechanisms, as well as challenges of HUC-MSCs in clinical translation.

EXPERT OPINION

HUC-MSCs seem to be an optimal choice for stem cell-based therapy. However, before the cells translate from basic to clinical research, some problems still remain to be solved: i) building regulatory guidelines as well as an efficient and safe manufacturing procedure; ii) establishing donor's genetic testing and long-term closely monitoring system; iii) conducting further clinical trials to determine the optimum and standard dosage, time, route, frequency and many other technical issues of HUC-MSCs transplantation.

A proposed novel stem cell therapy protocol for liver cirrhosis

Currently, there is not an effective therapy for cirrhosis of the liver except for liver transplant. However, finding a compatible liver is difficult due to the low supply and increased demand for healthy livers. Stem cell therapy may be a solution for liver cirrhosis. In our previous report, stem cells from Wharton's jelly and bone marrow were shown to improve liver function in a chemically induced liver fibrosis animal model. However, the immunological rejection of an allograft is always a risk for clinical application. In this study proposal, we suggest using human adipose-derived stem cells (ADSCs) because they are an immune-privileged cell type; they lack human leukocyte antigen-DR expression, and they also suppress the proliferation of activated allogenic lymphocytes and inhibit the production of inflammatory cytokines. In addition, ADSCs contain a sufficient amount of adult stem cells for autologous transplantation. Based on these benefits, ADSCs are promising candidates for clinical application when compared to other stem cell types. The aim of our study will be to investigate the safety and efficacy of autologous ADSCs for the clinical treatment of liver cirrhosis.

Advances in mesenchymal stem cells combined with traditional Chinese medicine therapy for liver fibrosis

Liver fibrosis is a primary cause of liver cirrhosis, and even hepatocarcinoma. Recently, the usage of mesenchymal stem cells (MSCs) has been investigated to improve liver fibrosis. It has been reported that the differentiation, proliferation and migration of MSCs can be regulated by traditional Chinese medicine treatment; however, the mechanisms are still unclear. In this article, the authors review the characteristics of MSCs such as multidirectional differentiation and homing, and its application in animal experiments and clinical trials. The authors also list areas that need further investigation, andlook at the future prospects of clinical application of MSCs.

Human adipose-derived mesenchymal stem cells are resistant to HBV infection during differentiation into hepatocytes in vitro

The therapeutic methods for chronic hepatitis B are limited. The shortage of organ donors and hepatitis B virus (HBV) reinfection obstruct the clinical application of orthotopic liver transplantation (OLT). In the present study, adipose-derived mesenchymal stem cells (AD-MSCs) and bone marrow-derived mesenchymal stem cells (BM-MSCs) were isolated from chronic hepatitis B patients and characterized for morphology, growth potency, surface phenotype and the differentiation potential. The results showed that both MSCs had adipogenic, osteogenic and neuron differentiation potential, and nearly all MSCs expressed CD105, CD44 and CD29. Compared with AD-MSCs, BM-MSCs of chronic hepatitis B patients proliferated defectively. In addition, the ability of AD-MSCs to differentiate into hepatocyte was evaluated and the susceptibility to HBV infection were assessed. AD-MSCs could differentiate into functional hepatocyte-like cells. These cells express the hepatic-specific markers and have glycogen production and albumin secretion function. AD-MSCs and hepatic differentiation AD-MSCs were not susceptible to infection by HBV in vitro. Compared with BM-MSCs, AD-MSCs may be alternative stem cells for chronic hepatitis B patients.

Effect of transplantation route on stem cell migration to fibrotic liver of rats via cellular magnetic resonance imaging

BACKGROUND AIMS

Assessing mesenchymal stromal cells (MSCs) after grafting is essential for understanding their migration and differentiation processes. The present study sought to evaluate via cellular magnetic resonance imaging (MRI) if transplantation route may have an effect on MSCs engrafting to fibrotic liver of rats.

METHODS

Rat MSCs were prepared, labeled with superparamagnetic iron oxide and scanned with MRI. Labeled MSCs were transplanted via the portal vein or vena caudalis to rats with hepatic fibrosis. MRI was performed in vitro before and after transplantation. Histologic examination was performed. MRI scan and imaging parameter optimization in vitro and migration under in vivo conditions were demonstrated.

RESULTS

Strong MRI susceptibility effects could be found on gradient echo-weighted, or T2∗-weighted, imaging sequences from 24 h after labeling to passage 4 of labeled MSCs in vitro. In vivo, MRI findings of the portal vein group indicated lower signal in liver on single shot fast spin echo-weighted, or T2-weighted, imaging and T2∗-weighted imaging sequences. The low liver MRI signal increased gradually from 0-3 h and decreased gradually from 3 h to 14 days post-transplantation. The distribution pattern of labeled MSCs in liver histologic sections was identical to that of MRI signal. It was difficult to find MSCs in tissues near the portal area on day 14 after transplantation; labeled MSCs appeared in fibrous tuberculum at the edge of the liver. No MRI signal change and a positive histologic examination were observed in the vena caudalis group.

CONCLUSIONS

The portal vein route seemed to be more beneficial than the vena caudalis on MSC migration to fibrotic liver of rats via MRI.

Human mesenchymal stem cell transfusion is safe and improves liver function in acute-on-chronic liver failure patients

Acute-on-chronic liver failure (ACLF) is a severe, life-threatening complication, and new and efficient therapeutic strategies for liver failure are urgently needed. Mesenchymal stem cell (MSC) transfusions have been shown to reverse fulminant hepatic failure in mice and to improve liver function in patients with end-stage liver diseases. We assessed the safety and initial efficacy of umbilical cord-derived MSC (UC-MSC) transfusions for ACLF patients associated with hepatitis B virus (HBV) infection. A total of 43 ACLF patients were enrolled for this open-labeled and controlled study; 24 patients were treated with UC-MSCs, and 19 patients were treated with saline as controls. UC-MSC therapy was given three times at 4-week intervals. The liver function, adverse events, and survival rates were evaluated during the 48-week or 72-week follow-up period. No significant side effects were observed during the trial. The UC-MSC transfusions significantly increased the survival rates in ACLF patients; reduced the model for end-stage liver disease scores; increased serum albumin, cholinesterase, and prothrombin activity; and increased platelet counts. Serum total bilirubin and alanine aminotransferase levels were significantly decreased after the UC-MSC transfusions. UC-MSC transfusions are safe in the clinic and may serve as a novel therapeutic approach for HBV-associated ACLF patients.

Human umbilical cord mesenchymal stem cells improve liver function and ascites in decompensated liver cirrhosis patients

Decompensated liver cirrhosis (LC), a life-threatening complication of chronic liver disease, is one of the major indications for liver transplantation. Recently, mesenchymal stem cell (MSC) transfusion has been shown to lead to the regression of liver fibrosis in mice and humans. This study examined the safety and efficacy of umbilical cord-derived MSC (UC-MSC) in patients with decompensated LC. A total of 45 chronic hepatitis B patients with decompensated LC, including 30 patients receiving UC-MSC transfusion, and 15 patients receiving saline as the control, were recruited; clinical parameters were detected during a 1-year follow-up period. No significant side-effects and complications were observed in either group. There was a significant reduction in the volume of ascites in patients treated with UC-MSC transfusion compared with controls (P < 0.05). UC-MSC therapy also significantly improved liver function, as indicated by the increase of serum albumin levels, decrease in total serum bilirubin levels, and decrease in the sodium model for end-stage liver disease scores. UC-MSC transfusion is clinically safe and could improve liver function and reduce ascites in patients with decompensated LC. UC-MSC transfusion, therefore, might present a novel therapeutic approach for patients with decompensated LC.

Efficacy of autologous bone marrow stem cell transplantation via the hepatic artery in combination with octreotide in the management of refractory ascites in patients with hepatic cirrhosis

AIM: To evaluate the efficacy of transplantation of autologous bone marrow stem cells via the hepatic artery in combination with octreotide in the treatment of refractory ascites in patients with cirrhosis.

METHODS: Thirty-three cirrhotic patients with refractory ascites were randomly divided into two groups: treatment group (n = 14) and control group (n = 19). The treatment group underwent conventional therapy, transplantation of autologous bone marrow stem cells via the hepatic artery, and treatment with octreotide, while the control group underwent conventional therapy and treatment with octreotide. The abdominal circumference, appetite, urine volume, the status of edema of the lower extremities and ascites, serum urea nitrogen, creatinine, albumin, and health status score were compared between before and after treatment and between the two groups.

RESULTS: No obvious complications occurred in all patients. One week after treatment, the total response rate showed no significant difference between the treatment and control groups (78.57% vs 78.95%, P > 0.05). However, the total response rate at week 4 was significantly higher in the treatment group than in the control group (92.86% vs 63.16%, P < 0.05). After four weeks of treatment, the improvements in abdominal circumference and urine volume were more significant in the treatment group than in the control group (both P < 0.05), and albumin was increased from 19.79 g/L ± 4.02 g/L to 27.34 g/L ± 4.00 g/L (P < 0.05). The healthy status, as assessed according to the Karnofsky Performance Status (KPS) scale, was better in the treatment group than in the control group (P < 0.05).

CONCLUSION: Transplantation of autologous bone marrow stem cells via the hepatic artery in combination with octreotide has good short-term efficacy and safety in the management of refractory ascites in patients with cirrhosis.

Identification of circulating CD90 CD73 cells in cirrhosis of liver

AIM

To identify circulating CD90(+) CD73(+) CD45(-) cells and evaluate their in vitro proliferating abilities.

METHODS

Patients with cirrhosis (n = 43), and healthy volunteers (n = 40) were recruited to the study. Mononuclear cells were isolated and cultured from the peripheral blood of controls and cirrhosis patients. Fibroblast-like cells that appeared in cultures were analyzed for morphological features, enumerated by flow cytometry and confirmed by immunocytochemistry (ICC). Colony forming efficiency (CFE) of these cells was assessed and expressed as a percentage.

RESULTS

In comparison to healthy volunteers, cells obtained from cirrhotic patients showed a significant increase (P < 0.001) in the percentage of CD90(+) CD73(+) CD45(-) cells in culture. Cultured cells also showed 10 fold increases in CFE. Flow cytometry and ICC confirmed that the proliferating cells expressed CD90(+) CD73(+) in the cultures from cirrhosis patients.

CONCLUSION

These results indicate the presence of circulating CD90(+) CD73(+) CD45(-) cells in patients with liver cirrhosis that have the potential to proliferate at a higher rate.

Treatment of different types of cirrhosis by autologous bone marrow stem cell transplantation via the hepatic artery: an analysis of 12 cases

AIM: To evaluate the efficacy and feasibility of autologous bone marrow stem cell transplantation via the hepatic artery in the treatment of different types and degrees of cirrhosis.

METHODS: Twelve patients with different types and degrees of decompensated cirrhosis, including 8 with hepatitis B-associated cirrhosis, 2 with alcoholic cirrhosis, and 2 with cryptogenic cirrhosis, were investigated retrospectively. Of all the patients, 4 had Child-Pugh grade B cirrhosis and 8 had grade C disease. At 2, 4 and 8 weeks after transplantation, the changes in symptoms (acratia, anorexia and abdominal distension), liver function and coagulation function were observed to analyze the efficacy and feasibility of autologous bone marrow stem cell transplantation via the hepatic artery in the treatment of cirrhosis.

RESULTS: Successful transplantation was achieved in all the 12 patients without obvious complications. The levels of plasma ALT and AST decreased after transplantation. TBIL decreased from 47.68 μmol/L ± 19.8 μmol/L at pretreatment to 36.45 μmol/L ± 20.78 μmol/L at 4 wk post-transplantation. Albumin increased from 18.79 g/L ± 7.02 g/L at pretreatment to 25.67 g/L ± 5.33 g/L at 2 wk. Although PT and PTA showed obvious improvement at 2 wk (P < 0.05), no significant improvement was noted at 4 and 8 wk (both P > 0.05). The total effective rate was 83.33% and 83.33% at 2 and 4 wk, respectively, but decreased to 66.67% at 8 wk. The improvement of TBIL and ALB in patients with alcoholic and cryptogenic cirrhosis at 2 and 4 wk was better than that in patients with hepatitis B-associated cirrhosis. The effective rate in patients with Child-Pugh B disease at 8 wk was significantly higher than that in patients with Child-Pugh C disease (100% vs 50%, P < 0.05).

CONCLUSION: Autologous bone marrow stem cell transplantation via the hepatic artery can improve hepatic cirrhosis, especially in patients with alcoholic or cryptogenic cirrhosis and those with a mild degree of cirrhosis.