Immunomodulatory role of mesenchymal stem cell therapy in liver fibrosis

Adipose Tissue and Umbilical Cord Tissue: Potential Sources of Mesenchymal Stem Cells for Liver Fibrosis Treatment

Background/Aims

Mesenchymal stem cells (MSCs) are potential alternatives for liver fibrosis treatment; however, their optimal sources remain uncertain. This study compares the ex-vivo expansion characteristics of MSCs obtained from adipose tissue (AT) and umbilical cord (UC) and assesses their therapeutic potential for liver fibrosis treatment.

Methods

Since MSCs from early to mid-passage numbers (P2-P6) are preferable for cellular therapy, we investigated the growth kinetics of AT-MSCs and UC-MSCs up to P6 and evaluated their therapeutic effects in a rat model of liver fibrosis induced by diethylnitrosamine.

Results

Results from the expansion studies demonstrated that both cell types exhibited bona fide characteristics of MSCs, including surface antigens, pluripotent gene expression, and differentiation potential. However, AT-MSCs demonstrated a shorter doubling time (58.2 ± 7.3 vs. 82.3 ± 4.3 h; P < 0.01) and a higher population doubling level (10.1 ± 0.7 vs. 8.2 ± 0.3; P < 0.01) compared to UC-MSCs, resulting in more cellular yield (230 ± 9.0 vs. 175 ± 13.2 million) in less time. Animal studies demonstrated that both MSC types significantly reduced liver fibrosis (P < 0.05 vs. the control group) while also improving liver function and downregulating fibrosis-associated gene expression.

Conclusion

AT-MSCs and UC-MSCs effectively reduce liver fibrosis. However, adipose cultures display an advantage by yielding a higher number of MSCs in a shorter duration, rendering them a viable choice for scenarios requiring immediate single-dose administration, often encountered in clinical settings.

Mesenchymal Stromal Cells: New Generation Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which has a high recurrence rate and is incurable due to a lack of effective treatment. Mesenchymal stromal cells (MSCs) are a class of pluripotent stem cells that have recently received a lot of attention due to their strong self-renewal ability and immunomodulatory effects, and a large number of experimental and clinical models have confirmed the positive therapeutic effect of MSCs on IBD. In preclinical studies, MSC treatment for IBD relies on MSCs paracrine effects, cell-to-cell contact, and its mediated mitochondrial transfer for immune regulation. It also plays a therapeutic role in restoring the intestinal mucosal barrier through the homing effect, regulation of the intestinal microbiome, and repair of intestinal epithelial cells. In the latest clinical trials, the safety and efficacy of MSCs in the treatment of IBD have been confirmed by transfusion of autologous or allogeneic bone marrow, umbilical cord, and adipose MSCs, as well as their derived extracellular vesicles. However, regarding the stable and effective clinical use of MSCs, several concerns emerge, including the cell sources, clinical management (dose, route and frequency of administration, and pretreatment of MSCs) and adverse reactions. This article comprehensively summarizes the effects and mechanisms of MSCs in the treatment of IBD and its advantages over conventional drugs, as well as the latest clinical trial progress of MSCs in the treatment of IBD. The current challenges and future directions are also discussed. This review would add knowledge into the understanding of IBD treatment by applying MSCs.

Bioreactor-based stem cell therapy for liver fibrosis

Stem cell therapy, achieved using mesenchymal stem cells (MSCs), has been highlighted for the treatment of liver fibrosis. Infusion into the circulatory system is a traditional application of MSCs; however, this approach is limited by phenotypic drift, stem cell senescence, and vascular embolism. Maintaining the therapeutic phenotype of MSCs while avoiding adverse infusion-related reactions is the key to developing next-generation stem cell therapy technologies. Here, we propose a bioreactor-based MSCs therapy to avoid cell infusion. In this scheme, 5% liver fibrosis serum was used to induce the therapeutic phenotype of MSCs, and a fluid bioreactor carrying a co-culture system of hepatocytes and MSCs was constructed to produce the therapeutic medium. In a rat model of liver fibrosis, the therapeutic medium derived from the bioreactor significantly alleviated liver fibrosis. Therapeutic mechanisms include immune regulation, inhibition of hepatic stellate cell activation, establishment of hepatocyte homeostasis, and recovery of liver stem cell subsets. Overall, the bioreactor-based stem cell therapy (scheme) described here represents a promising new strategy for the treatment of liver fibrosis and will be beneficial for the development of 'cell-free' stem cell therapy.

Arctium lappa L. polysaccharides enhanced the therapeutic effects of nasal ectomesenchymal stem cells against liver fibrosis by inhibiting the Wnt/β-catenin pathway

The oxidative microenvironment in fibrotic livers often diminishes the effectiveness of mesenchymal stem cells (MSCs)-based therapy. Recent research suggests that pharmacological pre-treatment could enhance the therapeutic performance of MSCs. In this study, we assessed the impact of Arctium lappa L. polysaccharides (ALP) on the biological properties of nasal ectomesenchymal stem cells (EMSCs) and investigated the augmenting effect of ALP pretreatment on EMSCs (ALP-EMSCs) for the treatment of liver fibrosis. ALP treatment demonstrated multiple biological impacts on EMSC functions regarding liver fibrosis: firstly, it maintained the stemness of the cells while boosting the EMSCs' paracrine effects; secondly, it increased the expression of anti-inflammatory and antioxidant factors; thirdly, it inhibited the activation of hepatic stellate cells (HSCs) and liver collagen build-up by modulating the Wnt/β-catenin signaling pathways. Collectively, these effects helped to halt the progression of liver fibrosis. Therefore, the use of ALP-EMSCs presents an innovative and promising approach for treating hepatic fibrosis in clinical scenarios.

Current Status and Prospect of Delivery Vehicle Based on Mesenchymal Stem Cell-Derived Exosomes in Liver Diseases

With the improvement of the average life expectancy and increasing incidence of obesity, the burden of liver disease is increasing. Liver disease is a serious threat to human health. Currently, liver transplantation is the only effective treatment for end-stage liver disease. However, liver transplantation still faces unavoidable difficulties. Mesenchymal stem cells (MSCs) can be used as an alternative therapy for liver disease, especially liver cirrhosis, liver failure, and liver transplantation complications. However, MSCs may have potential tumorigenic effects. Exosomes derived from MSCs (MSC-Exos), as the important intercellular communication mode of MSCs, contain various proteins, nucleic acids, and DNA. MSC-Exos can be used as a delivery system to treat liver diseases through immune regulation, apoptosis inhibition, regeneration promotion, drug delivery, and other ways. Good histocompatibility and material exchangeability make MSC-Exos a new treatment for liver diseases. This review summarizes the latest research on MSC-Exos as delivery vehicles in different liver diseases, including liver injury, liver failure, liver fibrosis, hepatocellular carcinoma (HCC), and ischemia and reperfusion injury. In addition, we discuss the advantages, disadvantages, and clinical application prospects of MSC-Exos-based delivery vectors in the treatment of liver diseases.