The therapeutic potential of bone marrow-derived mesenchymal stem cells on hepatic cirrhosis

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

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

miR-9-5p and miR-221-3p Promote Human Mesenchymal Stem Cells to Alleviate Carbon Tetrachloride-Induced Liver Injury by Enhancing Human Mesenchymal Stem Cell Engraftment and Inhibiting Hepatic Stellate Cell Activation

Mesenchymal stem cells (MSCs) have shown great potential for the treatment of liver injuries, and the therapeutic efficacy greatly depends on their homing to the site of injury. In the present study, we detected significant upregulation of hepatocyte growth factor (HGF) in the serum and liver in mice with acute or chronic liver injury. In vitro study revealed that upregulation of miR-9-5p or miR-221-3p promoted the migration of human MSCs (hMSCs) toward HGF. Moreover, overexpression of miR-9-5p or miR-221-3p promoted hMSC homing to the injured liver and resulted in significantly higher engraftment upon peripheral infusion. hMSCs reduced hepatic necrosis and inflammatory infiltration but showed little effect on extracellular matrix (ECM) deposition. By contrast, hMSCs overexpressing miR-9-5p or miR-221-3p resulted in not only less centrilobular necrosis and venous congestion but also a significant reduction of ECM deposition, leading to obvious improvement of hepatocyte morphology and alleviation of fibrosis around central vein and portal triads. Further studies showed that hMSCs inhibited the activation of hepatic stellate cells (HSCs) but could not decrease the expression of TIMP-1 upon acute injury and the expression of MCP-1 and TIMP-1 upon chronic injury, while hMSCs overexpressing miR-9-5p or miR-221-3p led to further inactivation of HSCs and downregulation of all three fibrogenic and proinflammatory factors TGF-β, MCP-1, and TIMP-1 upon both acute and chronic injuries. Overexpression of miR-9-5p or miR-221-3p significantly downregulated the expression of α-SMA and Col-1α1 in activated human hepatic stellate cell line LX-2, suggesting that miR-9-5p and miR-221-3p may partially contribute to the alleviation of liver injury by preventing HSC activation and collagen expression, shedding light on improving the therapeutic efficacy of hMSCs via microRNA modification.

Synergistic Hepatoprotective Effects of Mesenchymal Stem Cells and Platelet-Rich Plasma in a Rat Model of Bile Duct Ligation-Induced Liver Cirrhosis

Liver cirrhosis poses a global health challenge marked by significant prevalence and mortality. Current therapeutic options are limited by high costs and immune-mediated rejection, necessitating the exploration of innovative strategies to enhance hepatic self-rehabilitation, and counteract the underlying pathological mechanisms. We evaluated the hepatoprotective activity of rat adipose-derived mesenchymal stem cells (ADMSCs) in combination with platelet-rich plasma (PRP) and recombinant human hepatocyte growth factor (rh-HGF) on a rat model of liver fibrosis/cirrhosis induced by bile duct ligation (BDL). Treatment with PRP or rh-HGF alone did not yield significant hepatoprotection in the BDL-induced liver cirrhosis model. However, ADMSC transplantation alone exhibited the potential to alleviate impaired liver conditions. The combination of PRP and rh-HGF demonstrated superior ameliorative effects compared to either treatment alone. Notably, the combination of ADMSC + PRP or ADMSC + rh-HGF significantly enhanced hepatoprotective capacity compared to individual or combined PRP and rh-HGF therapies. Injection of ADMSC via the tail vein reduced inflammation, hepatocyte damage, and collagen deposition, improving overall liver function. This improvement was more pronounced when ADMSC was administered with PRP and rh-HGF versus monotherapy. Our study concludes that ADMSCs exert antifibrotic effects by inhibiting hepatic stellate cell proliferation, collagen synthesis, and inducing apoptosis. ADMSCs also demonstrate immune-modulatory effects and transdifferentiate into hepatic progenitor cells, secreting trophic factors, cytokines, and chemokines that promote impaired liver regeneration. The observed arrest in liver fibrosis progression highlights the potential therapeutic impact of these interventions.

Secretome of Hypoxia-Preconditioned Mesenchymal Stem Cells Promotes Liver Regeneration and Anti-Fibrotic Effect in Liver Fibrosis Animal Model

<b>Background and Objective:</b> Liver fibrosis (LF) is a most common pathological process characterized by the activation of hepatocytes leading to the accumulation of extracellular matrix (ECM). Hypoxia precondition treated in MSCs (H-MSCs) could enhance their immunomodulatory and regeneration capability, through expressing robust anti-inflammatory cytokines and growth factors, known as H-MSCs secretome (SH-MSCs) that are critical for the improvement of liver fibrosis. However, the study regarding the efficacy and mechanism of action of SH-MSCs in ameliorating liver fibrosis is still inconclusive. In this study, the therapeutic potential and underlying mechanism for SH-MSCs in the treatment of liver fibrosis were investigated. <b>Materials and Methods:</b> A rat model with liver fibrosis induced by CCl₄ was created and maintained for 8 weeks. The rats received intravenous doses of SH-MSCs and secretome derived from normoxia MSCs (SN-MSCs), filtered using a tangential flow filtration (TFF) system with different molecular weight cut-off categories, both at a dosage of 0.5 mL. The ELISA assay was employed to examine the cytokines and growth factors present in both SH-MSCs and SN-MSCs. On the ninth day, the rats were euthanized and liver tissues were collected for subsequent histological examination and analysis of mRNA expression. <b>Results:</b> The ELISA test revealed that SH-MSCs exhibited higher levels of VEGF, PDGF, bFGF, IL-10, TGF-β and IL-6 compared to SN-MSCs. <i>In vivo</i>, administration of SH-MSCs notably decreased mortality rates. It also demonstrated a reduction in liver fibrosis, collagen fiber areas, α-SMA positive staining and relative mRNA expression of TGF-β. Conversely, SN-MSCs also contributed to liver fibrosis improvement, although SH-MSCs demonstrated more favorable outcomes. <b>Conclusion:</b> Current findings suggested that SH-MSCs could improve CCl₄-induced liver fibrosis and decrease α-SMA and TGF-β expression.

Mesenchymal stromal cells in hepatic fibrosis/cirrhosis: from pathogenesis to treatment

Hepatic fibrosis/cirrhosis is a significant health burden worldwide, resulting in liver failure or hepatocellular carcinoma (HCC) and accounting for many deaths each year. The pathogenesis of hepatic fibrosis/cirrhosis is very complex, which makes treatment challenging. Endogenous mesenchymal stromal cells (MSCs) have been shown to play pivotal roles in the pathogenesis of hepatic fibrosis. Paradoxically, exogenous MSCs have also been used in clinical trials for liver cirrhosis, and their effectiveness has been observed in most completed clinical trials. There are still many issues to be resolved to promote the use of MSCs in the clinic in the future. In this review, we will examine the controversial role of MSCs in the pathogenesis and treatment of hepatic fibrosis/cirrhosis. We also investigated the clinical trials involving MSCs in liver cirrhosis, summarized the parameters that need to be standardized, and discussed how to promote the use of MSCs from a clinical perspective.

Apoptotic bone marrow-derived mononuclear cells accelerate liver regeneration after extended resection

Objective: to compare the efficiency of regenerative processes in the liver using apoptotic bone marrow-derived mononuclear cells (BMMCs) and intact BMMCs from healthy animals on an extended liver resection (ELR) model.

Materials and methods. Male Wistar rats (n = 77) with an ELR model (70–75%) were divided into 3 groups: group 1 (control with a single intraperitoneal injection of saline), group 2 (single intraperitoneal injection of unsorted intact BMMCs at a dose of 30–35 × 106, and group 3 (single intraperitoneal injection of apoptotic BMMCs at the same dose). Restoration of biochemical parameters of liver function and mass, as well as the emerging microstructural changes in hepatocytes in histological preparations, were monitored by assessing hepatocyte mitotic activity (MA) during the first 7–10 days after ELR.

Results. It was found that in groups 2 and 3, as compared with group 1, there was no death after ELR modeling, and that the biochemical parameters of liver function normalized more rapidly (at days 10–14). Hepatocyte MA in group 3 sharply increased as early as on day 1, and mitotic index (MI) averaged 14‰, reaching 20.9‰ in some experiments; MI in the control group remained at the baseline by this time, while in group 2, MI was only 3.2‰. In group 3, liver mass recovered more rapidly after ELR to baseline values already at days 8–10, whereas the recovery was at day 12–14 and day 17–20 in group 2 and group 1, respectively. It was suggested that the more pronounced increase in the efficiency of regenerative processes in the liver after ELR in group 3 after using apoptotic BMMCs was due to the release from these cells of a large spectrum of formed paracrine factors, including various classes of RNA molecules involved in the regeneration process.

Conclusion. Apoptotic BMMNCs have a more effective adaptive and regulatory potential than intact BMMCs because reorganizations are rapidly formed in the damaged liver cells, providing an early and more powerful activation of the targeted regenerative program.

Mesenchymal stromal cells (MSCs) and their exosome in acute liver failure (ALF): a comprehensive review

Recently, mesenchymal stromal cells (MSCs) and their derivative exosome have become a promising approach in the context of liver diseases therapy, in particular, acute liver failure (ALF). In addition to their differentiation into hepatocytes in vivo, which is partially involved in liver regeneration, MSCs support liver regeneration as a result of their appreciated competencies, such as antiapoptotic, immunomodulatory, antifibrotic, and also antioxidant attributes. Further, MSCs-secreted molecules inspire hepatocyte proliferation in vivo, facilitating damaged tissue recovery in ALF. Given these properties, various MSCs-based approaches have evolved and resulted in encouraging outcomes in ALF animal models and also displayed safety and also modest efficacy in human studies, providing a new avenue for ALF therapy. Irrespective of MSCs-derived exosome, MSCs-based strategies in ALF include administration of native MSCs, genetically modified MSCs, pretreated MSCs, MSCs delivery using biomaterials, and also MSCs in combination with and other therapeutic molecules or modalities. Herein, we will deliver an overview regarding the therapeutic effects of the MSCs and their exosomes in ALF. As well, we will discuss recent progress in preclinical and clinical studies and current challenges in MSCs-based therapies in ALF, with a special focus on in vivo reports.

From hair to liver: emerging application of hair follicle mesenchymal stem cell transplantation reverses liver cirrhosis by blocking the TGF-β/Smad signaling pathway to inhibit pathological HSC activation

Liver cirrhosis (LC) involves multiple systems throughout the body, and patients with LC often die of multiple organ failure. However, few drugs are useful to treat LC. Hair follicle mesenchymal stem cells (HF-MSCs) are derived from the dermal papilla and the bulge area of hair follicles and are pluripotent stem cells in the mesoderm with broad prospects in regenerative medicine. As an emerging seed cell type widely used in skin wound healing and plastic surgery, HF-MSCs show considerable prospects in the treatment of LC due to their proliferation and multidirectional differentiation capabilities. We established an LC model in C57BL/6J mice by administering carbon tetrachloride (CCl₄) and injected HF-MSCs through the tail vein to explore the therapeutic effects and potential mechanisms of HF-MSCs on LC. Here, we found that HF-MSCs improved liver function and ameliorated the liver pathology of LC. Notably, PKH67-labeled HF-MSCs were detected in the injured liver and expressed the hepatocyte-specific markers cytokeratin 18 (CK18) and albumin (ALB). In addition, in contrast to that in the LC group, the α-SMA expression showed a decreasing trend in the treatment group in vitro and in vivo, indicating that the pathological activation of hepatic stellate cells (HSCs) was inhibited by HF-MSC treatment. Moreover, the levels of transforming growth factor β (TGF-β1) and p-Smad3, a signaling molecule downstream of TGF-β1, were increased in mice with LC, while HF-MSC treatment reversed these changes in vivo and in vitro. Based on these findings, HF-MSCs may reverse LC by blocking the TGF-β/Smad pathway and inhibiting the pathological activation of HSCs, which may provide evidence for the application of HF-MSCs to treat LC.

ECM1 modified HF-MSCs targeting HSC attenuate liver cirrhosis by inhibiting the TGF-β/Smad signaling pathway

Hair follicle-derived mesenchymal stem cells (HF-MSCs) show considerable therapeutic potential for liver cirrhosis (LC). To improve the effectiveness of naïve HF-MSC treatments on LC, we used bioinformatic tools to identify an exogenous gene targeting HSCs among the differentially expressed genes (DEGs) in LC to modify HF-MSCs. Extracellular matrix protein 1 (ECM1) was identified as a DEG that was significantly downregulated in the cirrhotic liver. Then, ECM1-overexpressing HF-MSCs (ECM1-HF-MSCs) were transplanted into mice with LC to explore the effectiveness and correlated mechanism of gene-overexpressing HF-MSCs on LC. The results showed that ECM1-HF-MSCs significantly improved liver function and liver pathological injury in LC after cell therapy relative to the other treatment groups. Moreover, we found that ECM1-HF-MSCs homed to the injured liver and expressed the hepatocyte-specific surface markers ALB, CK18, and AFP. In addition, hepatic stellate cell (HSC) activation was significantly inhibited in the cell treatment groups in vivo and in vitro, especially in the ECM1-HF-MSC group. Additionally, TGF-β/Smad signal inhibition was the most significant in the ECM1-HF-MSC group in vivo and in vitro. The findings indicate that the genetic modification of HF-MSCs with bioinformatic tools may provide a broad perspective for precision treatment of LC.

Regenerative Potential of Mesenchymal Stem Cells' (MSCs) Secretome for Liver Fibrosis Therapies

Chronic liver injuries lead to liver fibrosis and then to end-stage liver cirrhosis. Liver transplantation is often needed as a course of treatment for patients in critical conditions, but limitations associated with transplantation prompted the continuous search for alternative therapeutic strategies. Cell therapy with stem cells has emerged as an attractive option in order to stimulate tissue regeneration and liver repair. Transplanted mesenchymal stem cells (MSCs) could trans-differentiate into hepatocyte-like cells and, moreover, show anti-fibrotic and immunomodulatory effects. However, cell transplantation may lead to some uncontrolled side effects, risks associated with tumorigenesis, and cell rejection. MSCs' secretome includes a large number of soluble factors and extracellular vesicles (EVs), through which they exert their therapeutic role. This could represent a cell-free strategy, which is safer and more effective than MSC transplantation. In this review, we focus on cell therapies based on MSCs and how the MSCs' secretome impacts the mechanisms associated with liver diseases. Moreover, we discuss the important therapeutic role of EVs and how their properties could be further used in liver regeneration.

Regulatory T Cells Improved the Anti-cirrhosis Activity of Human Amniotic Mesenchymal Stem Cell in the Liver by Regulating the TGF-β-Indoleamine 2,3-Dioxygenase Signaling

Liver fibrosis is a progression stage of chronic liver disease, while current therapies cannot cure or attune cirrhosis effectively. Human amniotic mesenchymal stromal cell (hAMSC) presented immunoregulatory and tissue repairability of multiple illnesses. Regulatory T cells (Treg) had been proved to be functional in reducing immune cell activity. We showed that co-infusion of hAMSC and Treg prevented mild liver fibrosis comparing with hAMSC or Treg alone group. In vitro study indicated that the addition of Treg or the supernatant of Treg improved the hepatocyte growth factor (HGF) secreting and cell differentiation ability of hAMSC. Reduction of TGF-β significantly decreased the HGF secreting and differentiation of hAMSC. Multiple signal neutralizers were added to the culture to understand further the mechanism, which showed that 1-MT, the suppressor of Indoleamine 2,3-dioxygenase (IDO), was involved in the effect of TGF-β in regulating hAMSC. Depletion of TGF-β or IDO signaling successfully abolished the effect of Treg in improving hAMSC's function both in vitro and vivo. Finally, our result indicated that Treg improved the function of hAMSC by regulating the TGF-β-IDO signaling and co-infusion of hAMSC and Treg provided a promising approach for treating liver cirrhosis.

The Immunomodulatory Properties of Mesenchymal Stem Cells Play a Critical Role in Inducing Immune Tolerance after Liver Transplantation

Although liver transplantation is considered to be the best choice for patients with end-stage liver diseases, postoperative immune rejection still cannot be overlooked. Patients with liver transplantation have to take immunosuppressive drugs for a long time or even their entire lives, in which heavy economic burden and side effects caused by the drugs have become the major impediment for liver transplantation. There is a growing body of evidences indicating that mesenchymal stem cell (MSC) transplantation, a promising tool in regenerative medicine, can be used as an effective way to induce immune tolerance after liver transplantation based on their huge expansion potential and unique immunomodulatory properties. MSCs have been reported to inhibit innate immunity and adaptive immunity to induce a tolerogenic microenvironment. In in vitro studies, transplanted MSCs show plasticity in immune regulation by altering their viability, migration, differentiation, and secretion in the interactions with the surrounding host microenvironment. In this review, we aim to provide an overview of the current understanding of immunomodulatory properties of MSCs in liver transplantation, to elucidate the potential mechanisms behind MSCs regulating immune response, especially in vivo and the influence of the microenvironment, and ultimately to discuss the feasible strategies to improve the clinical prognosis of liver transplantation. Only after exhaustive understanding of potential mechanisms of the MSC immunomodulation can we improve the safety and effectiveness of MSC treatment and achieve better therapeutic effects.

Bone Marrow-derived Mesenchymal Stem Cells Reverse Hepatic Fibrosis, Improved Vascularity, and Attenuate the Apoptosis in Carbon Tetrachloride-induced Hepatic Fibrosis Experimental Rats

Background: Liver fibrosis is a sequel of different chronic inflammatory diseases. The most effective treatment for end-stage liver fibrosis is liver transplantation; but the shortage of donor organs, immunological rejection, surgical complications, and high medical costs limit the transplantation. That’s why we are in argent need to develop new strategies in treatment.  Objectives: to evaluate the role of MSCs in regenerating liver cells and reverse hepatic fibrosis. Materials and Methods: 30 Animals were randomly divided into three groups (10 animals each): group 1: a negative control; group 2: induced liver fibrosis (pathological control).; group 3: induced liver fibrosis that received undifferentiated BM MSCs (3×106 cells/ml intraperitoneally/single dose); The extent of fibrosis, vascularization, and inflammation and hepatic cell apoptosis were evaluated together with assessment of liver functions. Results: The MSCs treated group showed significant improvement of liver functions, and attenuation of fibrosis histopathologicaly and down regulate the expression of TGF ß versus the induced fibrosis group. inflammatory marker(TNF,IL-6) were down regulated and vascularity was restored in MSCs treated group  compared to CCL4 induced fibrosis rats.  Conclusion: MSCs provide promising therapeutic agents in treatment of liver fibrosis.

Application of Modified Mesenchymal Stem Cells Transplantation in the Treatment of Liver Injury

Acute and chronic hepatitis, cirrhosis, and other liver diseases pose a serious threat to human health; however, liver transplantation is the only reliable treatment for the terminal stage of liver diseases. Previous researchers have shown that mesenchymal stem cells (MSCs) are characterized by differentiation and paracrine effects, as well as anti-oxidative stress and immune regulation functions. When MSCs are transplanted into animals, they migrate to the injured liver tissue along with the circulation, to protect the liver and alleviate the injury through the paracrine, immune regulation and other characteristics, making mesenchymal stem cell transplantation a promising alternative therapy for liver diseases. Although the efficacy of MSCs transplantation has been confirmed in various animal models of liver injury, many researchers have also proposed various pretreatment methods to improve the efficacy of mesenchymal stem cell transplantation, but there is still lack a set of scientific methods system aimed at improving the efficacy of transplantation therapy in scientific research and clinical practice. In this review, we summarize the possible mechanisms of MSCs therapy and compare the existing methods of MSCs modification corresponding to the treatment mechanism, hoping to provide as a reference to help future researchers explore a safe and simple transplantation strategy.

Mesenchymal stem cell therapy for liver disease: current status and future perspectives

PURPOSE OF REVIEW

Liver transplantation is the gold standard for the treatment of end-stage liver disease. However, a shortage of donor organs, high cost, and surgical complications limit the use of this treatment. Cellular therapies using hepatocytes, hematopoietic stem cells, bone marrow mononuclear cells, and mesenchymal stem cells (MSCs) are being investigated as alternative treatments to liver transplantation. The purpose of this review is to describe studies using MSC transplantation for liver diseases based on the reported literature and to discuss prospective research designed to improve the efficacy of MSC therapy.

RECENT FINDINGS

MSCs have several properties that show potential to regenerate injured tissues or organs, such as homing, transdifferentiation, immunosuppression, and cellular protective capacity. Additionally, MSCs can be noninvasively isolated from various tissues and expanded ex vivo in sufficient numbers for clinical evaluation.

SUMMARY

Currently, there is no approved MSC therapy for the treatment of liver disease. However, MSC therapy is considered a promising alternative treatment for end-stage liver diseases and is reported to improve liver function safely with no side effects. Further robust preclinical and clinical studies will be needed to improve the therapeutic efficacy of MSC transplantation.

Mesenchymal Stem Cells for the Treatment of Liver Disease: Present and Perspectives

Mesenchymal stem cell transplantation is an emerging therapy for treating chronic liver diseases. The potential of this treatment has been evaluated in preclinical and clinical studies. Although the mechanisms of mesenchymal stem cell transplantation are still not completely understood, accumulating evidence has revealed that their immunomodulation, differentiation, and antifibrotic properties play a crucial role in liver regeneration. The safety and therapeutic effects of mesenchymal stem cells in patients with chronic liver disease have been observed in many clinical studies. However, only modest improvements have been seen, partly because of the limited feasibility of transplanted cells at present. Here, we discuss several strategies targeted at improving viable cell engraftment and the potential challenges in the use of extracellular vesicle-based therapies for liver disease in the future.

Mesenchymal Stromal Cell Therapy in Novel Porcine Model of Diffuse Liver Damage Induced by Repeated Biliary Obstruction

In liver surgery, biliary obstruction can lead to secondary biliary cirrhosis, a life-threatening disease with liver transplantation as the only curative treatment option. Mesenchymal stromal cells (MSC) have been shown to improve liver function in both acute and chronic liver disease models. This study evaluated the effect of allogenic MSC transplantation in a large animal model of repeated biliary obstruction followed by partial hepatectomy. MSC transplantation supported the growth of regenerated liver tissue after 14 days (MSC group, n = 10: from 1087 ± 108 (0 h) to 1243 ± 92 mL (14 days); control group, n = 11: from 1080 ± 95 (0 h) to 1100 ± 105 mL (14 days), p = 0.016), with a lower volume fraction of hepatocytes in regenerated liver tissue compared to resected liver tissue (59.5 ± 10.2% vs. 70.2 ± 5.6%, p < 0.05). Volume fraction of connective tissue, blood vessels and bile vessels in regenerated liver tissue, serum levels of liver enzymes (AST, ALT, ALP and GGT) and liver metabolites (albumin, bilirubin, urea and creatinine), as well as plasma levels of IL-6, IL-8, TNF-α and TGF-β, were not affected by MSC transplantation. In our novel, large animal (pig) model of repeated biliary obstruction followed by partial hepatectomy, MSC transplantation promoted growth of liver tissue without any effect on liver function. This study underscores the importance of translating results between small and large animal models as well as the careful translation of results from animal model into human medicine.

Mesenchymal Stem Cells Suppress TGF-β Release to Decrease α-SMA Expression in Ameliorating CCl4-Induced Liver Fibrosis

Introduction:

Liver fibrosis (LF) is the excessive deposition of extracellular matrix (ECM), produced by overactivated hepatic stellate cells, following prolonged transforming growth factor-β (TGF-β) stimulation. The ability of mesenchymal stem cells (MSCs) to improve LF has been reported. However, the mechanisms of MSCs to ameliorate LF through suppressing TGF-β and α-smooth muscle actin (α-SMA) remains unclear.

Aim:

To investigate the effects of MSCs treatment on suppressing TGF-β levels and decreasing α-SMA expression in an LF model.

Methods:

In this study, wenty-four male Wistar rats were injected intraperitoneal (IP) with carbon tetrachloride (CCL4), twice weekly, for eight weeks, to induce LF. Rats were randomly assigned to six groups: Sham, Control, Sham-lo, Sham-hi, and MSC-treated groups, at doses of 1 x 10⁶ (T1) and 2x10⁶ (T2) cells. TGF-β levels were analyzed by enzyme-linked immunosorbent assay (ELISA), whereas α-SMA expression was determined by immunohistochemistry staining.

Results:

MSCs decreased the expression of TGF-β in T1 and T2 groups on day 3 and 14. The T2 group showed lower TGF-β levels than that in the T1 group. This finding was in line with the observed decrease in α-SMA expression and the number of collagen.

Conclusion:

MSCs treatment ameliorated LF by suppressing TGF-β production, leading to decreased α-SMA expression in a CCL4-induced LF animal model.

Mesenchymal stem cell therapy for liver disease: full of chances and challenges

Liver disease is a major health problem that endangers human health worldwide. Currently, whole organ allograft transplantation is the gold standard for the treatment of end-stage liver disease. A shortage of suitable organs, high costs and surgical complications limit the application of liver transplantation. Mesenchymal stem cell therapy has been considered as a promising alternative approach for end-stage liver disease. Some clinical trials have confirmed the effectiveness of MSC therapy for liver disease, but its application has not been promoted and approved. There are still many issues that should be solved prior to using MSC therapy in clinical applications. The types of liver disease that are most suitable for MSC application should be determined, and the preparation and engraftment of MSCs should be standardized. These may be bottlenecks that limit the use of MSCs. We investigated 22 completed and several ongoing clinical trials to discuss these questions from a clinical perspective. We also discussed the important mechanisms by which MSCs play a therapeutic role in liver disease. Finally, we also proposed novel prospective approaches that can improve the therapeutic effect of MSCs.

Therapeutic potential of bone marrow-derived mesenchymal stem cells and imatinib in a rat model of liver fibrosis

Considering the global increase in the prevalence of hepatic fibrosis and ineffective disease treatment, novel therapies are urgently needed. The current study is focused on comparing the therapeutic effects of mesenchymal stem cells (MSC)/imatinib combination therapy to single (MSCs or imatinib) therapy, in a rat model of carbon tetrachloride (CCL4)-induced liver fibrosis. Using rats, hepatic fibrosis was induced by injection of CCL4. Rats were divided into 5 groups: CCL4-induced hepatic fibrosis, phosphate buffered saline (PBS) treatment (vehicle control), Bone marrow-MSCs (BM_MSCs), imatinib, and bone marrow-MSCs/imatinib co-treatment. The therapeutic impact of these approaches was determined using histopathology, sirius-red staining, serum markers, and qRT-PCR for over expression of matrix components. IHC and Western blot were conducted for further confirmation of the results. Single treatment with MSCs or imatinib and the combination therapy, all significantly reduced serum levels of ALT, AST, and ALP concomitant with down-regulation of α-SMA, pro-collagen I, pro-collagen III, collagen IV, and laminin. A significant reduction of ECM components deposits and a decrease in α-SMA expression were detected in all treatment groups. Pathological observations demonstrated that 20% and 40% of the rats in the MSC and MSC/imatinib group were in grade F0 respectively, while 80% of the rats of the imatinib group were in grade 2. Even though all treatment strategies studied resulted in an equally potent reduction in the mRNA and protein expression levels of pro-fibrotic markers, in aspect of pathological observations, our results demonstrate the highest therapeutic potential of utilizing combination of BM-MSCs and imatinib.

Multifunctional nanoparticles in stem cell therapy for cellular treating of kidney and liver diseases

The review gives an overview of the mechanisms of internalization and distribution of nanoparticles in stem cells this is achieved via providing analysis of the methods used in exploring the migration routes of stem cells, and their reciprocity. In addition, exploring microenvironment target in the body, and tracking the fate of exogenously transplanted stem cells by using innovative and non-invasive techniques will also be discussed. Such techniques like magnetic resonance imaging (MRI), multimodality tracking, optical imaging, and nuclear medicine imaging, which were designed to follow up stem cell migration. This review will explain the various distinctive strategies to enhance homing of labeled stem cells with nanoparticles into damaged hepatic and renal tissues, this purpose was obtained by inducing a specific gene into stem cells, various chemokines, and applying an external magnetic field. Also, this work illustrates how to improve nanoparticles uptake by using transfection agents or covalently binding an exogenous protein (i.e., Human immunodeficiency virus-Tat protein) or conjugating a receptor-specific monoclonal antibody or make modifications to iron coat. It contains stem cell labeling methods such as extracellular labeling and internalization approaches. Ultimately, our review indicates trails of researchers in nanoparticles utilization in stem cell therapy in both kidney and liver diseases.

Toll-Like Receptor 5 Signaling Ameliorates Liver Fibrosis by Inducing Interferon β-Modulated IL-1 Receptor Antagonist in Mice

Bacterial flagellin, recognized by cell surface of Toll-like receptor (TLR) 5, is a potent activator of many types of cells, leading to the activation of innate or adaptive immunity, which are pivotal in regulating fibrotic process. However, the exact role of TLR5 signaling in hepatic fibrogenesis remains unclear, and this study aims to elucidate its underlying mechanisms. Flagellin was injected to hepatotoxin- and cholestasis-induced liver fibrosis murine models. Flagellin-induced TLR5 activation significantly decreased the severity of liver fibrosis. Interestingly, the expression levels of IL-1 receptor antagonist (IL1RN) and interferon (IFN)β markedly increased in fibrotic livers on flagellin treatment. Consistently, in vivo activation of TLR5 signaling markedly increased IFNβ and IL1RN expression in the livers. Notably, flagellin injection significantly exacerbated the severity of liver fibrosis in IFN-α/β receptor 1 (IFNAR1) knockout mice. Furthermore, hepatic expression of IL1RN in the fibrotic livers of IFNAR1 knockout mice was significantly lower than those of wild-type mice. In support of these findings, flagellin-mediated IL1RN production is not sufficient to alleviate the severity of hepatic fibroinflammatory responses in IFNAR1-deficient milieu. Finally, hepatic stellate cells treated with IL1RN had significantly decreased cellular activation and its associated fibrogenic responses. Collectively, manipulation of TLR5 signaling may be a promising therapeutic strategy for the treatment of liver fibrosis.

A Brief Analysis of Mesenchymal Stem Cells as Biological Drugs for the Treatment of Acute-on-Chronic Liver Failure (ACLF): Safety and Potency

Acute-on-Chronic Liver Failure (ACLF) is characterized by acute exacerbation of chronic hepatitis, organ failure, high mortality, and poor prognosis. At present, the clinical methods of treatment include comprehensive treatment with medicines, artificial liver system, and Orthotopic Liver Transplantation (OLT), and of these, OLT is considered the most effective treatment for ACLF. However, it is difficult for ACLF patients to benefit from OLT due to the shortage of liver donors, high cost, unpredictable postoperative complications, and long-term use of immunosuppressive drugs; therefore, it is important to explore a new treatment option. With the development of stem cell transplantation technology in recent years, several studies have shown that treatment of ACLF with Mesenchymal Stem Cells (MSCs) leads to higher survival rates, and has good tolerance and safety rates, thereby improving the liver function and quality of life of patients; it has also become one of the popular research topics in clinical trials. This paper summarizes the current clinical interventions and treatments of ACLF, including the clinical trials, therapeutic mechanisms, and research progress on MSC application in the treatment of ACLF. The problems and challenges of the development of MSC-based therapy in the future are also discussed.

Effect of Autologous Bone Marrow Stem Cell Therapy in Patients with Liver Cirrhosis: A Meta-analysis

Background and Aims: Although autologous bone marrow stem cell (BMSC) transplantation is an effective treatment for liver cirrhosis, there are few reports describing the optimal delivery route and number of injected BMSCs. Methods: A literature search was conducted using PubMed, ISI Web of Science, Cochrane Central Register of Controlled Trials, and EBSCO. A meta-analysis was performed to assess the effect of BMSCs on liver and coagulation function indices. Subgroup analysis was performed based on number of injected BMSCs, delivery route, and length of follow-up. Results: A total of 15 studies were selected from among 1903 potential studies for analysis. Autologous BMSC transplantation significantly improved aspartate aminotransferase, total bilirubin, albumin, prothrombin time, prothrombin activity, prothrombin concentration, Child-Pugh score, and model for end-stage liver disease. In the subgroup analysis of cell numbers, all four of the indices were significantly improved when the number of BMSCs was >4 × 10⁸. The subgroup analysis referring to the delivery route showed that arterial infusion increased the therapeutic effect over venous infusion. Finally, in the subgroup analysis of follow-up length, the results showed that BMSC therapy significantly improved liver function at 2 weeks after transplantation. In addition, this therapy improved coagulation 4 weeks after the transplant, with a maintenance of efficacy for up to 24 weeks. Conclusions: Autologous BMSC therapy is beneficial for liver improvement and coagulation in patients with liver cirrhosis. The therapeutic effect was generated at 2-4 weeks after transplantation. The effect lasted for 24 weeks but no more than 48 weeks. The greatest benefit to patients was observed with a 4 × 10⁸ autologous BMSC transplant via the hepatic artery.

Overproduction of Tenascin-C Driven by Lipid Accumulation in the Liver Aggravates Hepatic Ischemia/Reperfusion Injury in Steatotic Mice

The purpose of this study was to assess the significance of tenascin-C (Tnc) expression in steatotic liver ischemia/reperfusion injury (IRI). The critical shortage in donor organs has led to the use of steatotic livers in transplantation regardless of their elevated susceptibility to hepatic IRI. Tnc is an endogenous danger signal extracellular matrix molecule involved in various aspects of immunity and tissue injury. In the current study, mice were fed with a steatosis-inducing diet and developed approximately 50% hepatic steatosis, predominantly macrovesicular, before being subjected to hepatic IRI. We report here that lipid accumulation in hepatocytes inflated the production of Tnc in steatotic livers and in isolated hepatic stellate cells. Moreover, we show that the inability of Tnc-/- deficient steatotic mice to express Tnc significantly protected these mice from liver IRI. Compared with fatty controls, Tnc-/- steatotic mice showed significantly reduced serum transaminase levels and enhanced liver histological preservation at both 6 and 24 hours after hepatic IRI. The lack of Tnc expression resulted in impaired lymphocyte antigen 6 complex, locus (Ly6G) neutrophil and macrophage antigen-1 (Mac-1) leukocyte recruitment as well as in decreased expression of proinflammatory mediators (interleukin 1β, tumor necrosis factor α, and chemokine [C-X-C motif] ligand 2) after liver reperfusion. Myeloperoxidase (MPO) is the most abundant cytotoxic enzyme secreted by neutrophils and a key mediator of neutrophil-induced oxidative tissue injuries. Using an in vitro model of steatosis, we also show that Tnc markedly potentiated the effect of steatotic hepatocytes on neutrophil-derived MPO activity. In conclusion, our data support the view that inhibition of Tnc is a promising therapeutic approach to lessen inflammation in steatotic livers and to maximize their successful use in organ transplantation.

Mesenchymal stem cells in preclinical cancer cytotherapy: a systematic review

Mesenchymal stem cells (MSC) comprise a heterogeneous population of rapidly proliferating cells that can be isolated from adult (e.g., bone marrow, adipose tissue) as well as fetal (e.g., umbilical cord) tissues (termed bone marrow (BM)-, adipose tissue (AT)-, and umbilical cord (UC)-MSC, respectively) and are capable of differentiation into a wide range of non-hematopoietic cell types. An additional, unique attribute of MSC is their ability to home to tumor sites and to interact with the local supportive microenvironment which rapidly conceptualized into MSC-based experimental cancer cytotherapy at the turn of the century. Towards this purpose, both naïve (unmodified) and genetically modified MSC (GM-MSC; used as delivery vehicles for the controlled expression and release of antitumorigenic molecules) have been employed using well-established in vitro and in vivo cancer models, albeit with variable success. The first approach is hampered by contradictory findings regarding the effects of naïve MSC of different origins on tumor growth and metastasis, largely attributed to inherent biological heterogeneity of MSC as well as experimental discrepancies. In the second case, although the anti-cancer effect of GM-MSC is markedly improved over that of naïve cells, it is yet apparent that some protocols are more efficient against some types of cancer than others. Regardless, in order to maximize therapeutic consistency and efficacy, a deeper understanding of the complex interaction between MSC and the tumor microenvironment is required, as well as examination of the role of key experimental parameters in shaping the final cytotherapy outcome. This systematic review represents, to the best of our knowledge, the first thorough evaluation of the impact of experimental anti-cancer therapies based on MSC of human origin (with special focus on human BM-/AT-/UC-MSC). Importantly, we dissect the commonalities and differences as well as address the shortcomings of work accumulated over the last two decades and discuss how this information can serve as a guide map for optimal experimental design implementation ultimately aiding the effective transition into clinical trials.

Taking advantage of the potential of mesenchymal stromal cells in liver regeneration: Cells and extracellular vesicles as therapeutic strategies

Cell-based therapies for acute and chronic liver diseases are under continuous progress. Mesenchymal stem/stromal cells (MSCs) are multipotent cells able to migrate selectively to damaged tissue and contribute to its healing and regeneration. The MSC pro-regenerative effect occurs due to their immunomodulatory capacity and their ability to produce factors that promote cell protection and survival. Likewise, it has been observed that part of their paracrine effect is mediated by MSC-derived extracellular vesicles (EVs). EVs contain proteins, lipids and nucleic acids (DNA, mRNA, miRNA, lncRNA) from the cell of origin, allowing for intercellular communication. Recently, different studies have demonstrated that MSC-derived EVs could reproduce, at least in part, the biological effects obtained by MSC-based therapies. Moreover, due to EVs' stability for long periods of time and easy isolation methods they have become a therapeutic option to MSCs treatments. This review summarizes the latest results achieved in clinical trials using MSCs as cell therapy for liver regeneration, the role of EVs in liver physiopathology and the potential of MSCderived EVs as intercellular mediators and therapeutic tools in liver diseases.

Therapeutic potential effect of bone marrow-derived mesenchymal stem cells on chronic liver disease in murine Schistosomiasis Mansoni

Some reports have shown that mesenchymal stem cells (MSCs) therapy could ameliorate chemically-induced hepatic fibrosis. This research assesses the therapeutic action of bone marrow mesenchymal stem cells (BM-MSCs) on chronic diseased liver in Schistosoma mansoni infected mice. All infected female mice divided into three groups, one group (15 mice) treated with oral praziquantel (PZQ), second group (15 mice) received intravenous injection of BM-MSCs and third group (15 mice) treated with both MSCs + PZQ. Two control groups (15 mice each) subdivided into one infected and second healthy one. BM-MSCs were obtained from bones of both femur and tibia of male mice (30 mice), then cultured and characterized morphologically by detection of CD105 by flow cytometer. Liver tissues for all groups were examined histopathologically. Measuring of the collagen 1 gene expression was done by real-time PCR and immunohistochemical study to detect stem cells differentiation for detection of MSCs engraftments in liver tissue. MSCs treatment caused marked improvement and regression of fibrosis, and prevents deposition of collagen and reduced the expression of collagen 1 gene in infected mice on their liver tissues, especially when used with PZQ in mice treatment. It can be concluded that, MSCs is a good therapeutic method for liver fibrosis caused by S. mansoni infection.

Current Perspectives Regarding Stem Cell-Based Therapy for Liver Cirrhosis

Liver cirrhosis is a major cause of mortality and a common end of various progressive liver diseases. Since the effective treatment is currently limited to liver transplantation, stem cell-based therapy as an alternative has attracted interest due to promising results from preclinical and clinical studies. However, there is still much to be understood regarding the precise mechanisms of action. A number of stem cells from different origins have been employed for hepatic regeneration with different degrees of success. The present review presents a synopsis of stem cell research for the treatment of patients with liver cirrhosis according to the stem cell type. Clinical trials to date are summarized briefly. Finally, issues to be resolved and future perspectives are discussed with regard to clinical applications.

Hepatic recruitment of CD11b+Ly6C+ inflammatory monocytes promotes hepatic ischemia/reperfusion injury

Monocytes infiltrate damaged liver tissue during noninfectious liver injury and often have dual roles, perpetuating inflammation and promoting resolution of inflammation and fibrosis. However, how monocyte subsets distribute and are differentially recruited in the liver remain unclear. In the current study, the subpopulations of infiltrating monocytes were examined following liver ischemia/reperfusion (I/R) injury in mice using flow cytometry. CD11b⁺Ly6C high (Ly6C^hi) cells (inflammatory monocytes) and CD11b⁺Ly6C low cells (reparative monocytes) were recruited into the liver following I/R injury. Treatment with clodronate-loaded liposomes, which transiently deplete systemic macrophages, alleviated hepatic damage. Mice genetically deficient in C-C motif chemokine ligand 2 (CCL2), or its receptor C-C chemokine receptor 2 (CCR2), exhibited diminished hepatic damage compared with wild-type mice following I/R, by controlling intrahepatic inflammatory Ly6C^hi monocyte accumulation. In addition, the CCR2 specific inhibitor RS504393 alleviated hepatic I/R injury. The results suggest that the CCR2/ CCL2 axis an important role in monocyte infiltration and may represent a novel target for the treatment of liver I/R injury.

Clinical trials using mesenchymal stem cells in liver diseases and inflammatory bowel diseases

Mesenchymal stem cell (MSC) therapies have been used in clinical trials in various fields. These cells are easily expanded, show low immunogenicity, can be acquired from medical waste, and have multiple functions, suggesting their potential applications in a variety of diseases, including liver disease and inflammatory bowel disease. MSCs help prepare the microenvironment, in response to inflammatory cytokines, by producing immunoregulatory factors that modulate the progression of inflammation by affecting dendritic cells, B cells, T cells, and macrophages. MSCs also produce a large amount of cytokines, chemokines, and growth factors, including exosomes that stimulate angiogenesis, prevent apoptosis, block oxidation reactions, promote remodeling of the extracellular matrix, and induce differentiation of tissue stem cells. According to ClinicalTrials.gov, more than 680 clinical trials using MSCs are registered for cell therapy of many fields including liver diseases (more than 40 trials) and inflammatory bowel diseases (more than 20 trials). In this report, we introduce background and clinical studies of MSCs in liver disease and inflammatory bowel diseases.

Role of mesenchymal stem cells, their derived factors, and extracellular vesicles in liver failure

Liver failure is a severe clinical syndrome with a poor prognosis. Mesenchymal stem cell (MSC) transplantation has emerged as a new intervention in treating liver failure. It is conventionally recognized that MSCs exert their therapeutic effect mainly through transdifferentiation. Recently, published articles have shown that MSCs work in liver failure by secreting trophic and immunomodulatory factors as well as extracellular vesicles (EVs) before transdifferentiation. In particular,MSC-derived EVs have shown similar curative effects as MSCs. Here we review the role of MSCs as well as their derived factors and EVs in liver failure and discuss the use of MSC-derived EVs instead of intact MSCs in treating liver failure.

Quantitative evaluation of human bone mesenchymal stem cells rescuing fulminant hepatic failure in pigs

OBJECTIVE

Stem cell transplantation provides a promising alternative for the treatment of fulminant hepatic failure (FHF). However, it lacks fundamental understanding of stem cells' activities. Our objective was to clarify stem cell-recipient interactions for overcoming barriers to clinical application.

DESIGN

We used an in-house large-animal (pig) model of FHF rescue by human bone marrow mesenchymal stem cells (hBMSCs) and profiled the cells' activities. The control and transplantation groups of pigs (n=15 per group) both received a D-galactosamine (D-Gal) injection (1.5 g/kg). The transplantation group received hBMSCs via intraportal vein infusion (3×10⁶ cells/kg) immediately after D-Gal administration. The stem cell-recipient interactions were quantitatively evaluated by biochemical function, cytokine array, metabolite profiling, transcriptome sequencing and immunohistochemistry.

RESULTS

All pigs in the control group died within an average of 3.22 days, whereas 13/15 pigs in the transplantation group lived >14 days. The cytokine array and metabolite profiling analyses revealed that hBMSC transplantation suppressed D-Gal-induced life-threatening cytokine storms and stabilised FHF within 7 days, while human-derived hepatocytes constituted only ∼4.5% of the pig hepatocytes. The functional synergy analysis of the observed profile changes indicated that the implanted hBMSCs altered the pigs' cytokine responses to damage through paracrine effects. Delta-like ligand 4 was validated to assist liver restoration in both pig and rat FHF models.

CONCLUSIONS

Our results delineated an integrated model of the multifaceted interactions between stem cells and recipients, which may open a new avenue to the discovery of single molecule-based therapeutics that simulate stem cell actions.

Transplantation with autologous bone marrow-derived mesenchymal stem cells for alcoholic cirrhosis: Phase 2 trial

Bone marrow-derived mesenchymal stem cell (BM-MSC) transplantation has been suggested as an effective therapy for liver cirrhosis. The efficacy and safety of autologous BM-MSC transplantation in the treatment of alcoholic cirrhosis were investigated. Seventy-two patients with baseline biopsy-proven alcoholic cirrhosis who had been alcohol-abstinent for more than 6 months underwent a multicenter, randomized, open-label, phase 2 trial. Patients were randomly assigned to three groups: one control group and two autologous BM-MSC groups that underwent either one-time or two-time hepatic arterial injections of 5 × 10⁷ BM-MSCs 30 days after BM aspiration. A follow-up biopsy was performed 6 months after enrollment, and adverse events were monitored for 12 months. The primary endpoint was improvement in fibrosis quantification based on picrosirius red staining. The secondary endpoints included liver function tests, Child-Pugh score, and Model for End-stage Liver Disease score. Outcomes were analyzed by per-protocol analysis. In terms of fibrosis quantification (before versus after), the one-time and two-time BM-MSC groups were associated with 25% (19.5 ± 9.5% versus 14.5 ± 7.1%) and 37% (21.1 ± 8.9% versus 13.2 ± 6.7%) reductions in the proportion of collagen, respectively (P < 0.001). In the intergroup comparison, two-time BM-MSC transplantation in comparison with one-time BM-MSC transplantation was not associated with improved results in fibrosis quantification (P > 0.05). The Child-Pugh scores of both BM-MSC groups (one-time 7.6 ± 1.0 versus 6.3 ± 1.3 and two-time 7.8 ± 1.2 versus 6.8 ± 1.6) were also significantly improved following BM-MSC transplantation (P < 0.05). The proportion of patients with adverse events did not differ among the three groups.

CONCLUSION

Autologous BM-MSC transplantation safely improved histologic fibrosis and liver function in patients with alcoholic cirrhosis. (Hepatology 2016;64:2185-2197).

In vitro differentiated hepatic oval-like cells enhance hepatic regeneration in CCl4 -induced hepatic injury

Hepatic oval cells are likely to be activated during advanced stage of liver fibrosis to reconstruct damaged hepatic tissue. However, their scarcity, difficulties in isolation, and in vitro expansion hampered their transplantation in fibrotic liver. This study was aimed to investigate the repair potential of in vitro differentiated hepatic oval-like cells in CCl₄ -induced liver fibrosis. BMSCs and oval cells were isolated and characterized from C57BL/6 GFP⁺ mice. BMSCs were differentiated into oval cells by preconditioning with HGF, EGF, SCF, and LIF and analyzed for the oval cells-specific genes. Efficiency of oval cells to reduce hepatocyte injury was studied by determining cell viability, release of LDH, and biochemical tests in a co-culture system. Further, in vivo repair potential of differentiated oval cells was determined in CCl₄ -induced fibrotic model by gene expression analysis, biochemical tests, mason trichrome, and Sirius red staining. Differentiated oval cells expressed hepatic oval cells-specific markers AFP, ALB, CK8, CK18, CK19. These differentiated cells when co-cultured with injured hepatocytes showed significant hepato-protection as measured by reduction in apoptosis, LDH release, and improvement in liver functions. Transplantation of differentiated oval cells like cells in fibrotic livers exhibited enhanced homing, reduced liver fibrosis, and improved liver functions by augmenting hepatic microenvironment by improved liver functions. This preconditioning strategy to differentiate BMSCs into oval cell leads to improved survival and homing of transplanted cells. In addition, reduction in fibrosis and functional improvement in mice with CCl₄ -induced liver fibrosis was achieved.

Transplantation of MSCs Overexpressing HGF into a Rat Model of Liver Fibrosis

PURPOSE

The aim of this study is to evaluate the effect of overexpressing human hepatocyte growth factor (HGF) for mesenchymal stem cells (MSCs) in liver fibrosis regeneration and magnetic resonance (MR) tracking of MSCs in rat liver.

PROCEDURES

MSCs were transfected with ad-HGF/ad-green fluorescent protein (GFP) and labeled with superparamagnetic iron oxide (SPIO). The characteristics of SPIO-HGF/MSCs were investigated. Prussian blue staining for iron assessment was conducted in vitro and in vivo. SPIO-HGF/MSCs (group A) or SPIO-GFP/MSCs (group B) were transplanted into a rat model of liver fibrosis, and MR imaging of the rat liver was performed. The signal to noise ratio (SNR) and R2* (1/T2*) value were measured. Prussian blue staining was performed to detect the in vivo distribution of MSCs, and liver Ki67 immunohistochemistry (IHC) staining was studied. The serum levels of HGF, alanine aminotransferase (ALT) and hyaluronic acid (HA) were determined.

RESULTS

The positive rate of HGF transfection was 93.17 % and the HGF/MSCs were labeled with SPIO successfully (97.80 ± 1.06 %). Labeling of MSCs with SPIO did not alter cell proliferation in vitro. The signal intensity of liver T2* WI images decreased on day 1 after cell transplantation and recovered to pre-transplantation level on day 15 (group A) and day 13 (group B). The SNR of group A were significantly lower than that of group B (P = 0.006), and the R2* values of group A were significantly higher than those of group B (P < 0.001). The R2* value had a significantly negative correlation with SNR. There were more Prussian blue-positive cells in of group A were more than in group B in vivo. The positive rate of Ki67 was 16.11 ± 2.13 %, and the serum level of ALT/HA was decreased in group A.

CONCLUSION

HGF transfection improved MSCs localization in the liver and aided liver repair. The R2* value might be a feasible index in addition to SNR to track the SPIO-MSC transplantation in the liver.

Prospects for Adult Stem Cells in the Treatment of Liver Diseases

Hepatocytes constitute the main bulk of the liver and perform several essential functions. After injury, the hepatocytes have a remarkable capacity to regenerate and restore functionality. However, in some cases, the endogenous hepatocytes cannot replicate or restore the function, and liver transplantation, which is not exempt of complications, is required. Stem cells offer in theory the possibility of generating unlimited supply of hepatocytes in vitro due to their capacity to self-renew and differentiate when given the right cues. Stem cells isolated from an array of tissues have been investigated for their capacity to differentiate into hepatocyte-like cells in vitro and are employed in rescue experiments in vivo. Adult stem cells have gained in attractiveness over embryonic stem cells for liver cell therapy due to their origin, multipotentiality, and the possibility of autologous transplantation. This review deals with the promise and limitations of adult stem cells in clinically restoring liver functionality.

Ex Vivo Stromal Cell-Derived Factor 1-Mediated Differentiation of Mouse Bone Marrow Mesenchymal Stem Cells into Hepatocytes Is Enhanced by Chinese Medicine Yiguanjian Drug-Containing Serum

Yiguanjian is administered in traditional Chinese medicine for liver diseases and has been demonstrated to reduce liver fibrosis. This study investigated the effect of Yiguanjian drug-containing serum (YGJ) with Stromal Cell-Derived Factor 1 (SDF-1) and Hepatocyte Growth Factor (HGF) on the differentiation of murine bone-marrow-derived mesenchymal cells (BM-MSCs) into hepatocytes in vitro. Adherent MSCs were isolated from murine bone marrow. Differentiation was induced by 20 ng/mL HGF, 50 ng/mL SDF-1, and 20% Yiguanjian drug-containing serum for 7 to 28 days, and mature hepatocytes' marker albumin (ALB) and cholangiocytes' marker cytokeratin-18 (CK-18) were assessed by immunocytochemistry and western blot. BM-MSCs exhibited homogeneous spindle shape growth after subculture and stained positive for CD90 and negative for CD34. After induction with HGF + normal serum or YGJ for 14 days, HGF + SDF-1 + normal serum for 7 days, or HGF + SDF-1 + YGJ for 5 days, MSCs' morphology changed gradually and begun to resemble hepatocyte-like cells. Cultures supplemented with HGF + SDF-1 + YGJ contained significantly higher proportions of ALB and CK-18 positive cells than cultures supplemented with HGF + SDF-1 + normal serum at day 7. These observations corroborated the results of western blot. In conclusion, Yiguanjian drug-containing serum could facilitate the differentiation of murine BM-MSCs into hepatocytes in vitro and has a synergistic effect with SDF-1 and HGF.

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

Chronic alcohol consumption is a major cause of liver disease. The term alcoholic liver disease (ALD) refers to a spectrum of mild to severe disorders including steatosis, steatohepatitis, cirrhosis, and hepatocellular carcinoma. With limited therapeutic options, stem cell therapy offers significant potential for these patients. In this article, we review the pathophysiologic features of ALD and the therapeutic mechanisms of multipotent mesenchymal stromal cells, also referred to as mesenchymal stem cells (MSCs), based on their potential to differentiate into hepatocytes, their immunomodulatory properties, their potential to promote residual hepatocyte regeneration, and their capacity to inhibit hepatic stellate cells. The perfect match between ALD pathogenesis and MSC therapeutic mechanisms, together with encouraging, available preclinical data, allow us to support the notion that MSC transplantation is a promising therapeutic strategy to manage ALD onset and progression.

Mesenchymal Stem Cell-Mediated Effects of Tumor Support or Suppression

Mesenchymal stem cells (MSCs) can exhibit a marked tropism towards site of tumors. Many studies have reported that tumor progression and metastasis increase by MSCs. In contrast, other studies have shown that MSCs suppress growth of tumors. MSCs contribute to tumor growth promotion by several mechanisms: (1) transition to tumor-associated fibroblasts; (2) suppression of immune response; (3) promotion of angiogenesis; (4) stimulation of epithelial-mesenchymal transition (EMT); (5) contribution to the tumor microenvironment; (6) inhibition of tumor cell apoptosis; and (7) promotion of tumor metastasis. In contrast to the tumor-promoting properties, MSCs inhibit tumor growth by increasing inflammatory infiltration, inhibiting angiogenesis, suppressing Wnt signaling and AKT signaling, and inducing cell cycle arrest and apoptosis. In this review, we will discuss potential mechanisms by which MSC mediates tumor support or suppression and then the possible tumor-specific therapeutic strategies using MSCs as delivery vehicles, based on their homing potential to tumors.

Protective effects of extracts from Pomegranate peels and seeds on liver fibrosis induced by carbon tetrachloride in rats

BACKGROUND

Liver fibrosis is a feature in the majority of chronic liver diseases and oxidative stress is considered to be its main pathogenic mechanism. Antioxidants including vitamin E, are effective in preventing liver fibrogenesis. Several plant-drived antioxidants, such as silymarin, baicalin, beicalein, quercetin, apigenin, were shown to interfere with liver fibrogenesis. The antioxidans above are polyphenols, flavonoids or structurally related compounds which are the main chemical components of Pomegranate peels and seeds, and the antioxidant activity of Pomegranate peels and seeds have been verified. Here we investigated whether the extracts of pomegranate peels (EPP) and seeds (EPS) have preventive efficacy on liver fibrosis induced by carbon tetrachloride (CCl4) in rats and explored its possible mechanisms.

METHODS

The animal model was established by injection with 50 % CCl4 subcutaneously in male wistar rats twice a week for four weeks. Meanwhile, EPP and EPS were administered orally every day for 4 weeks, respectively. The protective effects of EPP and EPS on biochemical metabolic parameters, liver function, oxidative markers, activities of antioxidant enzymes and liver fibrosis were determined in CCl4-induced liver toxicity in rats.

RESULTS

Compared with the sham group, the liver function was worse in CCl4 group, manifested as increased levels of serum alanine aminotransferase, aspartate aminotransferase and total bilirubin. EPP and EPS treatment significantly ameliorated these effects of CCl4. EPP and EPS attenuated CCl4-induced increase in the levels of TGF-β1, hydroxyproline, hyaluronic acid laminin and procollagen type III. They also restored the decreased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and inhibited the formation of lipid peroxidized products in rats treated with CCl4.

CONCLUSION

The EPP and EPS have protective effects against liver fibrosis induced by CCl4, and its mechanisms might be associated with their antioxidant activity, the ability of decreasing the level of TGF-β1 and inhibition of collagen synthesis.

Mesenchymal stem cell therapy for cirrhosis: Present and future perspectives

Cirrhosis occurs as a result of various chronic liver injuries, which may be caused by viral infections, alcohol abuse and the administration of drugs and chemicals. Recently, bone marrow cells (BMCs), hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) have been used for developing treatments for cirrhosis. Clinical trials have investigated the therapeutic potential of BMCs, HSCs and MSCs for the treatment of cirrhosis based on their potential to differentiate into hepatocytes. Although the therapeutic mechanisms of BMC, HSC and MSC treatments are still not fully characterized, the evidence thus far has indicated that the potential therapeutic mechanisms of MSCs are clearer than those of BMCs or HSCs with respect to liver regenerative medicine. MSCs suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, reverse liver fibrosis and enhance liver functionality. This paper summarizes the clinical studies that have used BMCs, HSCs and MSCs in patients with liver failure or cirrhosis. We also present the potential therapeutic mechanisms of BMCs, HSCs and MSCs for the improvement of liver function.

Autologous bone marrow stem cell transplantation in patients with liver failure: a meta-analytic review

Autologous bone marrow stem cell (ABMSC) transplantation has been utilized in clinical practice to treat patients with liver failure, but the therapeutic effect remains to be defined. A meta-analysis is essential to assess clinical advantages of ABMSC transplantation in patients with liver failure. A systematic search of published works [eg, PubMed, Medline, Embase, Chin J Clinicians (Electronic edition), and Science Citation Index] was conducted to compare clinical outcomes of ABMSC transplantation in patients with liver failure. Meta-analytic results were tested by fixed-effects model or random-effects model, dependent on the characteristics of variables. A total of 534 patients from seven studies were included in final meta-analysis. Subsequent to ABMSC transplantation, there was no significant improvement in general symptom and signs such as loss of appetite, fatigue, and ascites. Activities of serum ALT were not significantly decreased with weighted mean difference (WMD) of -19.36 and 95% confidence interval (CI) -57.53 to 18.80 (P=0.32). Postoperative level of albumin (ALB) was expectedly enhanced by stem cell transplantation (WMD 2.97, 95% CI 0.52 to 5.43, P<0.05, I(2)=84%). Coagulation function was improved as demonstrated by a short prothrombin time (PT) (WMD -1.18, 95% CI -2.32 to -0.03, P<0.05, I(2)=6%), but was not reflected by prothrombin activity (PTA) (P=0.39). Total bilirubin (TBIL) was drastically diminished after ABMSC therapy (WMD -14.85, 95% CI -20.39 to -9.32, P<0.01, I(2)=73%). Model for end-stage liver disease (MELD) scores were dramatically reduced (WMD -2.27, 95% CI -3.53 to -1.02, P<0.01, I(2)=0%). The advantage of ABMSC transplantation could be maintained more than 24 weeks as displayed by time-courses of ALB, TBIL, and MELD score. ABMSC transplantation does provide beneficial effects for patients with liver failure. Therapeutic effects can last for 6 months. However, long-term effects need to be determined.

Mesenchymal stem cells: In vivo therapeutic application ameliorates carbon tetrachloride induced liver fibrosis in rats

BACKGROUND

Egypt has the highest prevalence of hepatitis C virus in the world with infection rate up to 60%, for which liver fibrosis or hepatic carcinoma is the final outcome. Stem cell therapy provides a new hope for hepatic repair instead of traditional treatment, liver transplantation, as it is safer, gives long term engraftment and avoid expensive immunosuppressive drugs and unexpected hazardous effects.

AIM

This work aimed at determining the therapeutic potential of mesenchymal stem cells (MSC) in hepatic repair as a new line of therapy for liver fibrosis.

METHODS

33 female albino rats were divided into three groups: Group I: 10 rats injected subcutaneously with olive oil, Group II: 13 rats injected with carbon tetrachloride (CCl4) and Group III: 10 rats injected with CCl4 then bone marrow derived MSC from male rats. Blood and liver tissue samples were taken from all rats for biochemical and histological study.

RESULTS

Liver functions for group II rats showed significant deterioration in response to CCl4 in addition to significant histological changes in liver lobules and portal areas. Those parameters tend to be normal in MSC-treated group. Group III rats revealed normalized liver function and histological picture. Meanwhile, most of the pathological lesions were still detected in rats of second group.

CONCLUSION

Undifferentiated MSCs have the ability to ameliorate CCl4 induced liver injury in albino rats in terms of liver functions and histological features. So, stem cell therapy can be considered clinically to offer a hope for patients suffering from liver fibrosis.

Mesenchymal stem cell therapy for liver fibrosis

Currently, the most effective treatment for end-stage liver fibrosis is liver transplantation; however, transplantation is limited by a shortage of donor organs, surgical complications, immunological rejection, and high medical costs. Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have the potential to differentiate into hepatocytes, and therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. In addition, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis and enhance liver functionality. Despite these advantages, issues remain; MSCs also have fibrogenic potential and the capacity to promote tumor cell growth and oncogenicity. This paper summarizes the properties of MSCs for regenerative medicine and their therapeutic mechanisms and clinical application in the treatment of liver fibrosis. We also present several outstanding risks, including their fibrogenic potential and their capacity to promote pre-existing tumor cell growth and oncogenicity.

Repeated versus single transplantation of mesenchymal stem cells in carbon tetrachloride-induced liver injury in mice

Despite its numerous limitations, liver transplants are the only definite cure for end-stage liver disease. Various stem cell populations may contribute to liver regeneration, of which there is accumulating evidence of the contribution of mesenchymal stem cells (MSCs). This study examines the hypothesis that repeated infusions of human bone marrow-derived MSCs (hBMMSCs)can improve liver injury in an experimental model. MSCs were intravenously transplanted into immunosuppressed mice with carbon tetrachloride (CCl(4))-induced liver fibrosis. Transplanting 3x10(6) MSCs in three divided doses improved survival,liver fibrosis and necrosis compared with injection of the same number of MSCs in a single dose. This was accompanied by increased influence on the expression of the fibrogenic/fibrolytic related genes Col1a1, Timp1 and Mmp13 in the repeated transplant group. Repeat administration of MSCs was three times more effective in homing of PKH-tagged transplanted cells 3 weeks post-transplant compared with the single transplant group. The benefits of repeated transplants may be of considerable significance in clinical trials on liver failure.