Transplantation of bone marrow cells reduces CCl4 -induced liver fibrosis in mice

Allometrically scaling tissue forces drive pathological foreign-body responses to implants via Rac2-activated myeloid cells

Small animals do not replicate the severity of the human foreign-body response (FBR) to implants. Here we show that the FBR can be driven by forces generated at the implant surface that, owing to allometric scaling, increase exponentially with body size. We found that the human FBR is mediated by immune-cell-specific RAC2 mechanotransduction signalling, independently of the chemistry and mechanical properties of the implant, and that a pathological FBR that is human-like at the molecular, cellular and tissue levels can be induced in mice via the application of human-tissue-scale forces through a vibrating silicone implant. FBRs to such elevated extrinsic forces in the mice were also mediated by the activation of Rac2 signalling in a subpopulation of mechanoresponsive myeloid cells, which could be substantially reduced via the pharmacological or genetic inhibition of Rac2. Our findings provide an explanation for the stark differences in FBRs observed in small animals and humans, and have implications for the design and safety of implantable devices.

Potential advantages of genetically modified mesenchymal stem cells in the treatment of acute and chronic liver diseases

Liver damage caused by toxicity can lead to various severe conditions, such as acute liver failure (ALF), fibrogenesis, and cirrhosis. Among these, liver cirrhosis (LC) is recognized as the leading cause of liver-related deaths globally. Unfortunately, patients with progressive cirrhosis are often on a waiting list, with limited donor organs, postoperative complications, immune system side effects, and high financial costs being some of the factors restricting transplantation. Although the liver has some capacity for self-renewal due to the presence of stem cells, it is usually insufficient to prevent the progression of LC and ALF. One potential therapeutic approach to improving liver function is the transplantation of gene-engineered stem cells. Several types of mesenchymal stem cells from various sources have been suggested for stem cell therapy for liver disease. Genetic engineering is an effective strategy that enhances the regenerative potential of stem cells by releasing growth factors and cytokines. In this review, we primarily focus on the genetic engineering of stem cells to improve their ability to treat damaged liver function. We also recommend further research into accurate treatment methods that involve safe gene modification and long-term follow-up of patients to increase the effectiveness and reliability of these therapeutic strategies.

Cell and Tissue Therapy for the Treatment of Chronic Liver Disease

Liver disease is an important clinical problem, impacting 600 million people worldwide. It is the 11th-leading cause of death in the world. Despite constant improvement in treatment and diagnostics, the aging population and accumulated risk factors led to increased morbidity due to nonalcoholic fatty liver disease and steatohepatitis. Liver transplantation, first established in the 1960s, is the second-most-common solid organ transplantation and is the gold standard for the treatment of liver failure. However, less than 10% of the global need for liver transplantation is met at the current rates of transplantation due to the paucity of available organs. Cell- and tissue-based therapies present an alternative to organ transplantation. This review surveys the approaches and tools that have been developed, discusses the distinctive challenges that exist for cell- and tissue-based therapies, and examines the future directions of regenerative therapies for the treatment of liver disease.

Vitamin E pretreated Wharton's jelly-derived mesenchymal stem cells attenuate CCl4-induced hepatocyte injury in vitro and liver fibrosis in vivo

Oxidative microenvironment in fibrotic liver alleviates the efficacious outcome of mesenchymal stem cells (MSCs)-based cell therapy. Recent evidence suggests that pharmacological pretreatment is a rational approach to harness the MSCs with higher therapeutic potential. Here, we investigated whether Vitamin E pretreatment can boost the antifibrotic effects of Wharton's jelly-derived MSCs (WJMSCs). We used rat liver-derived hepatocytes injured by CCl₄ treatment in co-culture system with Vitamin E pretreated-WJMSCs (Vit E-WJMSCs) to evaluate the hepatoprotective effect of Vit E-WJMSCs. After 24 h of co-culturing, we found that Vit E-WJMSCs rescued injured hepatocytes as hepatocyte injury-associated medium (AST, ALT, and ALP) and mRNA (Cyp2e1, Hif1-α, and Il-1β) markers reduced to normal levels. Subsequently, CCl₄-induced liver fibrosis rat models were employed to examine the antifibrotic potential of Vit E-WJMSCs. After 1 month of cell transplantation, it was revealed that Vit E-WJMSCs transplantation ceased fibrotic progression, as evident by improved hepatic architecture and functions, more significantly in comparison to naïve WJMSCs. In addition, Vit E-WJMSCs transplantation decreased the expressions of fibrosis-associated gene (Tgf-β1, α-Sma, and Col1α1) markers in the liver parenchyma. Intriguingly, the results of tracing experiments discovered that more WJMSCs engrafted in the Vit E-WJMSCs treated rat livers compared to naïve WJMSCs treated livers. These findings implicate that pretreatment of WJMSCs with Vitamin E improves their tolerance to hostile niche of fibrotic liver; thereby further enhancing their efficacy for hepatic fibrosis.

C-Kit, a Double-Edged Sword in Liver Regeneration and Diseases

Previous studies have reported an important role of c-kit in embryogenesis and adulthood. Activation of the SCF/KIT signal transduction pathway is customarily linked to cell proliferation, migration and survival thus influence hematopoiesis, pigmentation, and spermatogenesis. The role of c-kit in the liver is controversial, it is however argued that it is a double-edged sword in liver regeneration and diseases. First, liver c-kit⁺ cells, including oval cells, bile epithelial cells, and part of hepatocytes, participate in liver tissue repair by regenerating target cells according to the type of liver injury. At the same time, c-kit⁺ mast cells, act as immature progenitors in circulation, playing a critical role in liver fibrosis. Furthermore, c-kit is also a proto-oncogene. Notably, c-kit overexpression regulates gastrointestinal stromal tumors. Various studies have explored on c-kit and hepatocellular carcinoma, nevertheless, the intricate roles of c-kit in the liver are largely understudied. Herein, we extensively summarize previous studies geared toward providing hints for future clinical and basic research.

Combination of mesenchymal stem cell-conditioned medium and botulinum toxin type A for treating human hypertrophic scars

BACKGROUND

Both mesenchymal stem cell-conditioned medium (MSC CM) and Botox have demonstrated therapeutic effects for hypertrophic scar (HS). It is unclear whether a synergistic effect occurs when these treatments are used in combination. We aimed to investigate the therapeutic effects of MSC CM and Botox alone when compared with those of a combined regimen on HS.

METHODS

Fibroblasts from human HS were isolated and treated with Dulbecco's modified Eagle's medium (DMEM), MSCCM, or Botox alone or a combination of MSCCM and Botox. We also used an in vivo HS-buried null mice model to investigate the efficacy of combination treatment.

RESULTS

The results demonstrated that the combination of MSC CM and Botox downregulated both mRNA and protein levels of type I collagen, type III collagen, and alpha-smooth muscle actin (α-SMA) in HS fibroblasts. The combined regimen also suppressed fibroblast proliferative activity, increased apoptosis, and displayed significant inhibitory effects on the contractile ability of HS fibroblasts compared to MSC CM, Botox, or DMEM alone. Using an in vivo HS-buried null mice model, significant scar weight reduction, cell apoptosis, and less α-SMA expression were observed from the combined regimen of MSC CM and Botox compared to those from the other groups. The combined regimen also significantly improved arrangement and deposition of collagen fibers.

CONCLUSIONS

This study demonstrates that a combination of MSC CM and Botox exhibited a significant therapeutic effect compared to monotherapy. Clinical translation of this therapy should be further considered.

The role of stem cells in liver injury and repair

Introduction: Liver disease is an increasing cause of worldwide mortality, and currently the only curative treatment for end-stage liver disease is whole organ allograft transplantation. Whilst this is an effective treatment, there is a shortage of suitable grafts and consequently some patients die whilst on the waiting list. Cell therapy provides an alternative treatment to increase liver function and potentially ameliorate fibrosis. Areas covered: In this review, we discuss the different cellular sources for therapy investigated to date in humans including mature hepatocytes, hematopoietic stem cells, mesenchymal stromal cells and hepatic progenitor cells. Cells investigated in animals include embryonic stem cells, induced pluripotent stem cells and directly reprogrammed cells. We then appraise the experience and evidence base underlying each cell type. Expert opinion: We discuss how this field may evolve in the years to come focusing on opportunities to enhance the intrinsic regenerative response with therapeutic targets and cell therapies. Growing expertise in tissue engineering will likely lead to increasingly complex bio-reactors and bio-artificial livers, which open a further avenue to restore liver function and delay or prevent the need for transplantation.

Repeated Autologous Bone Marrow Transfusion through Portal Vein for Treating Decompensated Liver Cirrhosis after Splenectomy

Objective

This study is aimed at examining the impact of repeated intraportal autologous bone marrow transfusion (ABMT) in patients with decompensated liver cirrhosis after splenectomy.

Methods

A total of 25 patients with decompensated liver cirrhosis undergoing splenectomy were divided into ABMT and control groups. The portal vein was cannulated intraoperatively using Celsite Implantofix through the right gastroomental vein. Both groups were given a routine medical treatment. Then, 18 mL of autologous bone marrow was transfused through the port in the patients of the ABMT group 1 week, 1 month, and 3 months after laminectomy, while nothing was given to the control group. All patients were monitored for adverse events. Liver function tests, including serum albumin (ALB), alanine aminotransferase (ALT), total bilirubin (TB), prothrombin activity (PTA), cholinesterase (CHE), α-fetoprotein (AFP), and liver stiffness measurement (LSM), were conducted before surgery and 1, 3, and 6 months after surgery.

Results

Significant improvements in ALB, ALT, and CHE levels and decreased LSM were observed in the ABMT group compared with those in the control group (P < 0.05). TB and PTA improved in both groups but with no significant differences between the groups. No significant changes were observed in AFP in the control group, but it decreased in the ABMT group. No major adverse effects were noted during the follow-up period in the patients of either group.

Conclusions

Repeated intraportal ABMT was clinically safe, and liver function of patients significantly improved. Therefore, this therapy has the potential to treat patients with decompensated liver cirrhosis after splenectomy. This trial was registered with the identification number of ChiCTR-ONC-17012592.

Transplantation of human matrix metalloproteinase-1 gene-modified bone marrow-derived mesenchymal stem cell attenuates CCL4-induced liver fibrosis in rats

It has been reported that bone marrow-derived mesenchymal stem cells (BMSCs) alleviated liver fibrosis. We investigated whether BMSCs transfected with human matrix metalloproteinase 1 (BMSCs/MMP1) would improve their therapeutic effect in liver fibrosis induced by carbon tetrachloride (CCl₄) in rats. BMSCs were transfected with an adenovirus carrying enhanced green fluorescence protein (GFP) and human MMP1 gene. BMSCs or BMSCs/MMP1 were directly injected into fibrotic rats via the tail vein. GFP-labeled cells appeared in the fibrotic liver after BMSC transplantation. The expression of BMSCs/MMP1 elevated levels of MMP1 in vitro. Although BMSC administration reduced liver fibrosis, transplantation of BMSCs/MMP1 enhanced the reduction of liver fibrosis to a higher level. Treatment with BMSCs/MMP1 not only decreased collagen content but also suppressed activation of hepatic stellate cells (HSCs) in fibrotic liver, which led to subsequent improvement of both liver injury and fibrosis. Treatment with BMSCs/MMP1 resulted in an improved therapeutic effect compared with BMSCs alone, which is probably because of the sustainably expressed MMP1 level in the liver. BMSCs/MMP1 transplantation not only improved biochemical parameters but also attenuated progression of liver fibrosis, suggesting that BMSCs may be a potential cell source in preventing liver fibrosis and MMP1 gene may enhance the anti-fibrotic effect of BMSCs.

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.

The Human Amnion Epithelial Cell Secretome Decreases Hepatic Fibrosis in Mice with Chronic Liver Fibrosis

Background: Hepatic stellate cells (HSCs) are the primary collagen-secreting cells in the liver. While HSCs are the major cell type involved in the pathogenesis of liver fibrosis, hepatic macrophages also play an important role in mediating fibrogenesis and fibrosis resolution. Previously, we observed a reduction in HSC activation, proliferation, and collagen synthesis following exposure to human amnion epithelial cells (hAEC) and hAEC-conditioned media (hAEC-CM). This suggested that specific factors secreted by hAEC might be effective in ameliorating liver fibrosis. hAEC-derived extracellular vesicles (hAEC-EVs), which are nanosized (40–100 nm) membrane bound vesicles, may act as novel cell–cell communicators. Accordingly, we evaluated the efficacy of hAEC-EV in modulating liver fibrosis in a mouse model of chronic liver fibrosis and in human HSC.

Methods: The hAEC-EVs were isolated and characterized. C57BL/6 mice with CCl₄-induced liver fibrosis were administered hAEC-EV, hAEC-CM, or hAEC-EV depleted medium (hAEC-EVDM). LX2 cells, a human HSC line, and bone marrow-derived mouse macrophages were exposed to hAEC-EV, hAEC-CM, and hAEC-EVDM. Mass spectrometry was used to examine the proteome profile of each preparation.

Results: The extent of liver fibrosis and number of activated HSCs were reduced significantly in CCl₄-treated mice given hAEC-EVs, hAEC-CM, and hAEC EVDM compared to untreated controls. Hepatic macrophages were significantly decreased in all treatment groups, where a predominant M2 phenotype was observed. Human HSCs cultured with hAEC-EV and hAEC-CM displayed a significant reduction in collagen synthesis and hAEC-EV, hAEC-CM, and hAEC-EVDM altered macrophage polarization in bone marrow-derived mouse macrophages. Proteome analysis showed that 164 proteins were unique to hAEC-EV in comparison to hAEC-CM and hAEC-EVDM, and 51 proteins were co-identified components with the hAEC-EV fraction.

Conclusion: This study provides novel data showing that hAEC-derived EVs significantly reduced liver fibrosis and macrophage infiltration to an extent similar to hAEC-EVDM and hAEC-CM. hAEC-EV-based therapy may be a potential therapeutic option for liver fibrosis.

Muse Cells, a New Type of Pluripotent Stem Cell Derived from Human Fibroblasts

A new type of mesenchymal stem cells (MSCs) that expresses stage-specific embryonic antigen 3 (SSEA-3) and the mesenchymal cell marker CD105 are known as multilineage-differentiating stress-enduring (Muse) cells. Studies have shown that stem cells in suspension cultures are more likely to generate embryoid body-like stem cell spheres and maintain an undifferentiated phenotype and pluripotency. We separated Muse cells derived from human dermal fibroblasts by long-term trypsin incubation (LTT) through suspension cultures in methylcellulose. The Muse cells obtained expressed several pluripotency markers, including Nanog, Oct4, Sox2, and SSEA-3, and could differentiate in vitro into cells of the three germ layers, such as hepatocytes (endodermal), neural cells (ectodermal) and adipocytes, and osteocytes (mesodermal cells). These cells showed a low level of DNA methylation and a high nucleo-cytoplasmic ratio. Our study provides an innovative and exciting platform for exploring the potential cell-based therapy of various human diseases using Muse cells as well as their great possibility for regenerative medicine.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Adipose tissue-derived stem cells suppress hypertrophic scar fibrosis via the p38/MAPK signaling pathway

BACKGROUND

Hypertrophic scars (HS) generally occur after injury to the deep layers of the dermis, resulting in functional deficiency for patients. Growing evidence has been identified that the supernatant of adipose tissue-derived stem cells (ADSCs) significantly ameliorates fibrosis of different tissues, but limited attention has been paid to its efficacy on attenuating skin fibrosis. In this study, we explored the effect and possible mechanism of ADSC-conditioned medium (ADSC-CM) on HS.

METHOD

Real-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting were used to detect the expression of collagen I (Col1), collagen III (Col3), and α-smooth muscle actin (α-SMA) after fibroblasts and cultured HS tissues were stimulated with ADSC-CM and p38 inhibitor/activator. Immunofluorescence staining was performed to test the expression of α-SMA. Masson's trichrome staining, hematoxylin and eosin (H&E) staining, and immunohistochemistry staining were carried out to assess the histological and pathological change of collagen in the BALB/c mouse excisional model. All data were analyzed by using SPSS17.0 software. Statistical analysis was performed by Student's t tests.

RESULTS

The in vitro and ex vivo study revealed ADSC-CM decreased the expression of Col1, Col3, and α-SMA. Together, thinner and orderly arranged collagen was manifested in HS tissues cultured with ADSC-CM. Dramatically, the assessed morphology showed an accelerated healing rate, less collagen deposition, and col1- and col3-positive cells in the ADSC-CM treated group. Importantly, the protein level of p-p38 was downregulated in a concentration-dependent manner in HS-derived fibroblasts with ADSC-CM treatment, which further decreased the expression of p-p38 after the application of its inhibitor, SB203580. SB203580 led to an obvious decline in the expression of Col1, Col3, and α-SMA in fibroblasts and cultured HS tissues and presented more ordered arrangement and thinner collagen fibers in BALB/c mice. Lastly, anisomycin, an agonist of p38, upregulated the expression of fibrotic proteins and revealed more disordered structure and denser collagen fibers.

CONCLUSION

This study demonstrated that ADSC-CM could decrease collagen deposition and scar formation in in vitro, ex vivo and in vivo experiments. The regulation of the p38/MAPK signaling pathway played an important role in the process. The application of ADSC-CM may provide a novel therapeutic strategy for HS treatment, and the anti-scarring effect can be achieved by inhibition of the p38/MAPK signaling pathway.

PIN1 Suppresses the Hepatic Differentiation of Pulp Stem Cells via Wnt3a

This study aimed to investigate the role of PIN1 on the hepatic differentiation of human dental pulp stem cells (hDPSCs) and its signaling pathway, as well as the potential therapeutic effects of hDPSC transplantation and PIN1 inhibition on CCl₄ (carbon tetrachloride)-induced liver fibrosis in mice. The in vitro results showed that hepatic differentiation was suppressed by infection with adenovirus-PIN1 and promoted by PIN1 inhibitor juglone via the downregulation of Wnt3a and β-catenin. Compared with treatment with either hDPSC transplantation or juglone alone, the combination of hDPSCs and juglone into CCl₄-injured mice significantly suppressed liver fibrosis and restored serum levels of alanine transaminase, aspartate transaminase, and ammonia. Collectively, the present study shows for the first time that PIN1 inhibition promotes hepatic differentiation of hDPSCs through the Wnt/β-catenin pathway. Furthermore, juglone in combination with hDPSC transplantation effectively treats liver fibrosis, suggesting that hDPSC transplantation with PIN1 inhibition may be a novel therapeutic candidate for the treatment of liver injury.

Autologous bone marrow transplantation in decompensated liver: Systematic review and meta-analysis

AIM: To evaluate the efficacy of autologous bone marrow mononuclear cell transplantation in decompensated liver disease.

METHODS: Medline, EMBASE, PubMed, Science Direct, and the Cochrane Library were searched for relevant studies. Retrospective case-control studies were included along with randomized clinical trials. Meta-analysis was performed in line with recommendations from the Cochrane Collaboration software review manager. Heterogeneity was assessed using a random-effects model.

RESULTS: Four randomized controlled trials and four retrospective studies were included. Cell transplantation increased serum albumin level by 1.96 g/L (95%CI: 0.74-3.17; P = 0.002], 2.55 g/L (95%CI: 0.32-4.79; P = 0.03), and 3.65 g/L (95%CI: 0.76-6.54; P = 0.01) after 1, 3, and 6 mo, respectively. Patients who had undergone cell transplantation also had a lower level of total bilirubin [mean difference (MD): -1.37 mg/dL; 95%CI: -2.68-(-0.06); P = 0.04] after 6 mo. This decreased after 1 year when compared to standard treatment (MD: -1.26; 95%CI: -2.48-(-0.03); P = 0.04]. A temporary decrease in alanine transaminase and aspartate transaminase were significant in the cell transplantation group. However, after 6 mo treatment, patients who had undergone cell transplantation had a slightly longer prothrombin time (MD: 5.66 s, 95%CI: 0.04-11.28; P = 0.05). Changes in the model for end-stage liver disease score and Child-Pugh score were not statistically significant.

CONCLUSION: Autologous bone marrow transplantation showed some benefits in patients with decompensated liver disease. However, further studies are still needed to verify its role in clinical treatment for end-stage liver disease.

Inhibition of hepatic stellate cells by bone marrow-derived mesenchymal stem cells in hepatic fibrosis

BACKGROUND/AIMS

Therapies involving bone-marrow-derived mesenchymal stem cells (BM-MSCs) have considerable potential in the management of hepatic disease. BM-MSCs have been investigated in regenerative medicine due to their ability to secrete various growth factors and cytokines that regress hepatic fibrosis and enhance hepatocyte functionality. The aim of this study was to determine the antifibrosis effect of BM-MSCs on activated hepatic stellate cells (HSCs) and the mechanism underlying how BM-MSCs modulate the function of activated HSCs.

METHODS

We used HSCs in both direct and indirect co-culture systems with BM-MSCs to evaluate the antifibrosis effect of BM-MSCs. The cell viability and apoptosis were evaluated by a direct co-culture system of activated HSCs with BM-MSCs. The activations of both HSCs alone and HSCs with BM-MSCs in the direct co-culture system were observed by immunocytochemistry for alpha-smooth muscle actin (α-SMA). The levels of growth factors and cytokines were evaluated by an indirect co-culture system of activated HSCs with BM-MSCs.

RESULTS

The BM-MSCs in the direct co-culture system significantly decreased the production of α-SMA and the viability of activated HSCs, whereas they induced the apoptosis of activated HSCs. The BM-MSCs in the indirect co-culture system decreased the production of transforming growth factor-β1 and interleukin (IL)-6, whereas they increased the production of hepatocyte growth factor and IL-10. These results confirmed that the juxtacrine and paracrine effects of BM-MSCs can inhibit the proliferative, fibrogenic function of activated HSCs and have the potential to reverse the fibrotic process by inhibiting the production of α-SMA and inducing the apoptosis of HSCs.

CONCLUSIONS

These results have demonstrated that BM-MSCs may exert an antifibrosis effect by modulating the function of activated HSCs.

Use of a transjugular intrahepatic portosystemic shunt combined with autologous bone marrow cell infusion in patients with decompensated liver cirrhosis: an exploratory study

BACKGROUND AIMS

Currently, there is no treatment for decompensated liver cirrhosis except for liver transplantation. The safety and effect on liver function of a transjugular intrahepatic portosystemic shunt (TIPS) with and without autologous bone marrow cell (BMC) infusion in patients with decompensated liver cirrhosis were determined.

METHODS

Ten patients who were diagnosed with decompensated liver cirrhosis during the period from September 2011 to July 2012 were enrolled in this study. The patients underwent TIPS (TIPS group) or combined treatment with TIPS and BMC infusion through the hepatic artery (TIPS+BMC group). All patients were monitored for adverse events, liver function and complications caused by portal hypertension during a period of 52 weeks.

RESULTS

The number of infused BMCs was 2.65 ± 1.20 ×10(9). Significant improvements in the serum levels of albumin and total bilirubin and decreased Child-Pugh scores were observed in patients treated with both TIPS and BMCs (P < 0.05), whereas no such changes were observed in the TIPS group. Endoscopic findings showed that varices in the esophagus and the gastric fundus were alleviated after either treatment. All 10 patients showed a complete or partial resolution of ascites at 4 weeks. No major adverse effects were noted during the follow-up period for patients in either group.

CONCLUSIONS

TIPS combined with BMC infusion is clinically safe; the treatment improved liver function and alleviated complications caused by portal hypertension; therefore, this combination has potential for treatment of patients with decompensated liver cirrhosis.

Paracrine action of mesenchymal stromal cells delivered by microspheres contributes to cutaneous wound healing and prevents scar formation in mice

BACKGROUND AIMS

Accumulating evidence suggests that mesenchymal stromal cells (MSCs) participate in wound healing to favor tissue regeneration and inhibit fibrotic tissue formation. However, the evidence of MSCs to suppress cutaneous scar is extremely rare, and the mechanism remains unidentified. This study aimed to demonstrate whether MSCs-as the result of their paracrine actions on damaged tissues-would accelerate wound healing and prevent cutaneous fibrosis.

METHODS

For efficient delivery of MSCs to skin wounds, microspheres were used to maintain MSC potency. Whether MSCs can accelerate wound healing and alleviate cutaneous fibrosis through paracrine action was investigated with the use of a Transwell co-culture system in vitro and a murine model in vivo.

RESULTS

MSCs cultured on gelatin microspheres fully retained their cell surface marker expression profile, proliferation, differentiation and paracrine potential. Co-cultures of MSCs and fibroblasts indicated that the benefits of MSCs on suppressing fibroblast proliferation and its fibrotic behavior induced by inflammatory cytokines probably were caused by paracrine actions. Importantly, microspheres successfully delivered MSCs into wound margins and significantly accelerated wound healing and concomitantly reduced the fibrotic activities of cells within the wounds and excessive accumulation of extracellular matrix as well as the transforming growth factor-β1/transforming growth factor-β3 ratio.

CONCLUSIONS

This study provides insight into what we believe to be a previously undescribed, multifaceted role of MSC-released protein in reducing cutaneous fibrotic formation. Paracrine action of MSCs delivered by microspheres may thus qualify as a promising strategy to enhance tissue repair and to prevent excessive fibrosis during cutaneous wound healing.

Mobilization of endogenous bone marrow-derived stem cells in a thioacetamide-induced mouse model of liver fibrosis

The clinical significance of enhancing endogenous circulating haematopoietic stem cells is becoming increasingly recognized, and the augmentation of circulating stem cells using granulocyte-colony stimulating factor (G-CSF) has led to promising preclinical and clinical results for several liver fibrotic conditions. However, this approach is largely limited by cost and the infeasibility of maintaining long-term administration. Preclinical studies have reported that StemEnhance, a mild haematopoietic stem cell mobilizer, promotes cardiac muscle regeneration and remedies the manifestation of diabetes. However, the effectiveness of StemEnhance in ameliorating liver cirrhosis has not been studied. This study is the first to evaluate the beneficial effect of StemEnhance administration in a thioacetamide-induced mouse model of liver fibrosis. StemEnhance augmented the number of peripheral CD34-positive cells, reduced hepatic fibrosis, improved histopathological changes, and induced endogenous liver proliferation. In addition, VEGF expression was up-regulated, while TNF-α expression was down-regulated in thioacetamide-induced fibrotic livers after StemEnhance intake. These data suggest that StemEnhance may be useful as a potential therapeutic candidate for liver fibrosis by inducing reparative effects via mobilization of haematopoietic stem cells.

Effect of bone marrow-derived mesenchymal stem cells on hepatic fibrosis in a thioacetamide-induced cirrhotic rat model

Background

Cirrhosis is a long-term consequence of chronic hepatic injury with fibrosis. No effective therapy is currently available for decompensated cirrhosis except liver transplantation. Hence, we investigated the effect of bone marrow-derived mesenchymal stem cells (BM-MSCs) on hepatic fibrosis in a thioacetamide (TAA)-induced cirrhotic rat model.

Methods

The BM-MSCs were injected directly into the right liver lobe twice, at 6 and 8 weeks during the 12-week TAA administration, in thioacetamide (TAA)-induced cirrhotic rats model, and hepatic fibrosis was evaluated. At 12 weeks, the effect of BM-MSCs on hepatic fibrosis was analyzed histomorphologically using the Laennec fibrosis scoring system, and the collagen proportionate area was quantified. Cirrhosis-related factors, such as transforming growth factor β1 (TGF-β1), type 1 collagen (collagen-1), α-smooth muscle actin (α-SMA), and P-Smad3/Smad3 expression levels, were evaluated using real-time polymerase chain reaction and western blot assays.

Results

According to the Laennec fibrosis scoring system, histological improvement was observed in hepatic fibrosis after BM-MSC treatment (P <0.01). The percentage of the collagen proportionate area decreased from 16.72 ± 5.51 to 5.06 ± 1.27 after BM-MSC treatment (P <0.01). The content of hepatic hydroxyproline was significantly lower in the BM-MSC treated group (46.25 ± 13.19) compared to the untreated cirrhotic group (85.81 ± 17.62; P <0.01). BM-MSC administration significantly decreased TGF-β1, collagen-1, and α-SMA expression in TAA-induced cirrhotic rats (P <0.01). We also confirmed P-Smad3/Smad3, downstream effectors of the TGF-β1 signaling pathway, and found that MSC transplantation inhibited Smad3 phosphorylation.

Conclusions

BM-MSC treatment attenuated hepatic fibrosis in rats with TAA-induced cirrhosis, raising the possibility of the clinical use of BM-MSCs in the treatment of cirrhosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-014-0198-6) contains supplementary material, which is available to authorized users.

Bone marrow stem cell therapy for liver disease

Liver disease is a rising cause of mortality and morbidity, and treatment options remain limited. Liver transplantation is curative but limited by donor organ availability, operative risk and long-term complications. The contribution of bone marrow (BM)-derived stem cells to tissue regeneration has been recognised and there is considerable interest in the potential benefits of BM stem cells in patients with liver disease. In chronic liver disease, deposition of fibrous scar tissue inhibits hepatocyte proliferation and leads to portal hypertension. Although initial reports had suggested transdifferentiation of stem cells into hepatocytes, the beneficial effects of BM stem cells are more likely derived from the ability to breakdown scar tissue and stimulate hepatocyte proliferation. Studies in animal models have yielded promising results, although the exact mechanisms and cell type responsible have yet to be determined. Small-scale clinical studies have quickly followed and, although primarily designed to examine safety and feasibility of this approach, have reported improvements in liver function in treated patients. Well-designed, controlled studies are required to fully determine the benefits of BM stem cell therapy.

Outcomes of autologous bone marrow mononuclear cell transplantation in decompensated liver cirrhosis

AIM: To determine the long-term efficacy of autologous bone marrow mononuclear cells (BM-MNCs) transplantation in terms of improving liver function and reducing complications in patients with decompensated cirrhosis.

METHODS: A total of 47 inpatients with decompensated liver cirrhosis were enrolled in this trial, including 32 patients undergoing a single BM-MNCs transplantation plus routine medical treatment, and 15 patients receiving medical treatment only as controls. Forty-three of 47 patients were infected with hepatitis B virus. Bone marrow of 80-100 mL was obtained from each patient and the BM-MNCs suspension was transfused into the liver via the hepatic artery. The efficacy of BM-MNCs transplantation was monitored during a 24-mo follow-up period.

RESULTS: Liver function parameters in the two groups were observed at 1 mo after BM-MNCs transfusion. Prealbumin level was 118.3 ± 25.3 mg/L vs 101.4 ± 28.7 mg/L (P = 0.047); albumin level was 33.5 ± 3.6 g/L vs 30.3 ± 2.2 g/L (P = 0.002); total bilirubin 36.9 ± 9.7 mmol/L vs 45.6 ± 19.9 mmol/L (P = 0.048); prothrombin time 14.4 ± 2.3 s vs 15.9 ± 2.8 s (P = 0.046); prothrombin activity 84.3% ± 14.3% vs 74.4% ± 17.8% (P = 0.046); fibrinogen 2.28 ± 0.53 g/L vs 1.89 ± 0.44 g/L (P = 0.017); and platelet count 74.5 ± 15.7 × 10⁹/L vs 63.3 ± 15.7 × 10⁹/L (P = 0.027) in the treatment group and control group, respectively. Differences were statistically significant. The efficacy of BM-MNCs transplantation lasted 3-12 mo as compared with the control group. Serious complications such as hepatic encephalopathy and spontaneous bacterial peritonitis were also significantly reduced in BM-MNCs transfused patients compared with the controls. However, these improvements disappeared 24 mo after transplantation.

CONCLUSION: BM-MNCs transplantation is safe and effective in patients with decompensated cirrhosis. It also decreases the incidence of serious complications.

Soluble factors derived from human amniotic epithelial cells suppress collagen production in human hepatic stellate cells

BACKGROUND

Intravenous infusion of human amniotic epithelial cells (hAECs) has been shown to ameliorate hepatic fibrosis in murine models. Hepatic stellate cells (HSCs) are the principal collagen-secreting cells in the liver. The aim of this study was to investigate whether factors secreted by hAECs and present in hAEC-conditioned medium (CM) have anti-fibrotic effects on activated human HSCs.

METHODS

Human AECs were isolated from the placenta and cultured. Human hepatic stellate cells were exposed to hAEC CM to determine potential anti-fibrotic effects.

RESULTS

HSCs treated for 48 h with hAEC CM displayed a significant reduction in the expression of the myofibroblast markers α-smooth muscle actin and platelet-derived growth factor. Expression of the pro-fibrotic cytokine transforming growth factor-β1 (TGF-β1) and intracellular collagen were reduced by 45% and 46%, respectively. Human AEC CM induced HSC apoptosis in 11.8% of treated cells and reduced HSC proliferation. Soluble human leukocyte antigen-G1, a hAEC-derived factor, significantly decreased TGF-β1 and collagen production in activated HSCs, although the effect on collagen production was less than that of hAEC CM. The reduction in collagen and TGF-B1 could not be attributed to PGE2, relaxin, IL-10, TGF-B3, FasL or TRAIL.

CONCLUSIONS

Human AEC CM treatment suppresses markers of activation, proliferation and fibrosis in human HSCs as well as inducing apoptosis and reducing proliferation. Human AEC CM treatment may be effective in ameliorating liver fibrosis and warrants further study.

Histological improvement following administration of autologous bone marrow-derived mesenchymal stem cells for alcoholic cirrhosis: a pilot study

BACKGROUND

In experimental models, bone marrow-derived mesenchymal stem cells (BM-MSCs) have the capacity to differentiate into hepatocytes and exhibit antifibrotic effects. However, there have been no studies in humans with alcoholic cirrhosis.

AIM

The aim of this study was to elucidate the antifibrotic effect of BM-MSCs in patients with alcoholic cirrhosis, as a phase II clinical trial.

METHODS

Twelve patients (11 males, 1 female) with baseline biopsy-proven alcoholic cirrhosis who had been alcohol free for at least 6 months were enrolled. BM-MSCs were isolated from each patient's BM and amplified for 1 month, and 5 × 10(7) cells were then injected twice, at weeks 4 and 8, through the hepatic artery. One patient was withdrawn because of ingestion of alcohol. Finally, 11 patients completed the follow-up biopsy and laboratory tests at 12 weeks after the second injection. The primary outcome was improvement in the patients' histological features.

RESULTS

According to the Laennec fibrosis system, histological improvement was observed in 6 of 11 patients (54.5%). The Child-Pugh score improved in ten patients (90.9%) and the levels of transforming growth factor-β1, type 1 collagen and α-smooth muscle actin significantly decreased (as assessed by real-time reverse transcriptase polymerase chain reaction) after BM-MSCs therapy (P < 0.05). No significant complications or side effects were observed during this study.

CONCLUSIONS

Bone marrow-derived mesenchymal stem cells therapy in alcoholic cirrhosis induces a histological and quantitative improvement of hepatic fibrosis.

Accumulation of xenotransplanted canine bone marrow cells in NOD/SCID/γc(null) mice with acute hepatitis induced by CCl4

Bone marrow cell infusion (BMI) has recently been suggested as an effective therapy for refractory liver disease; however, the efficiency of BMI using canine bone marrow cells (cBMCs) has not been reported. We evaluated the accumulation potential of cBMCs in a mouse model of acute liver failure. Acute hepatitis was induced by carbon tetrachloride (CCl4) treatment in NOD/SCID/γc(null)(NOG) mice and wild-type (WT) C57BL mice, and the characteristics of liver dysfunction and the degree of hepatic injury and regeneration were compared between the two mouse models. Next, female CCl4-treated NOG mice were xenotransplanted with male PKH26-labeled cBMCs, and the potential of cBMCs to accumulate in injured liver tissue compartments was examined. Fluorescence microscopy was performed to histologically detect the infused cBMCs, and DNA polymerase chain reaction was performed for detection of the male Y chromosome (SRY gene) in the recipient female NOG mice. The number of PKH26-positive cBMCs transplanted in the liver tissue gradually increased in the NOG mice. The infused cBMCs were located in the necrotic area of the liver at an early stage after transplantation, and most had accumulated a week after transplantation. However, the therapeutic efficacy of the xenotransplantation remained unclear, because no significant differences were observed concerning the extent liver injury and regeneration between the cBMC-transplanted and saline control mice. These results suggest that cBMCs will specifically accumulate in injured liver tissue and that BMC transplantation may have the potential to repair liver deficiency.

Mesenchymal stem cells restore CCl4-induced liver injury by an antioxidative process

We have investigated BM (bone marrow)-derived MSCs (mesenchymal stem cells) for the treatment of liver injury. It was hypothesized that MSC-mediated resolution of liver injury could occur through an antioxidative process. After being injected with CCl4 (carbon tetrachloride), mice were injected with syngenic BM-derived MSCs or normal saline. Oxidative stress activity of the MSCs was determined by the analysis of ROS (reactive oxygen species) and SOD (superoxide dismutase) activity. In addition, cytoprotective genes of the liver tissue were assessed by real-time PCR and ARE (antioxidant-response element) reporter assay. Up-regulated ROS of CCl4-treated liver cells was attenuated by co-culturing with MSCs. Suppression of SOD by adding an SOD inhibitor decreased the effect of MSCs on injured liver cells. MSCs significantly increased SOD activity and inhibited ROS production in the injured liver. The gene expression levels of Hmox-1 (haem oxygenase-1), BI-1 (Bax inhibitor-1), HGF (hepatocyte growth factor), GST (glutathione transferase) and Nrf2 (nuclear factor-erythoid 2 p45 subunit-related factor 20), attenuated by CCl4, were increased up to basal levels after MSC transplantation. In addition, MSCs induced an ARE, shown by luciferase activity, which represented a cytoprotective response in the injured liver. Evidence of a new cytoprotective effect is shown in which MSCs promote an antioxidant response and supports the potential of using MSC transplantation as an effective treatment modality for liver disease.

Bone marrow cell transplantation is associated with fibrogenic cells apoptosis during hepatic regeneration in cholestatic rats

Liver fibrosis is accompanied by hepatocyte death and proliferation of α-SMA+ fibrogenic cells (activated hepatic stellate cells and myofibroblasts), which synthesize extracellular matrix components that contribute to disorganization of the hepatic parenchyma and loss of liver function. Therefore, apoptosis of these fibrogenic cells is important to hepatic regeneration. This study aimed to analyze the effect of cell therapy using bone marrow mononuclear cell (BMMNC) transplantation on α-SMA expression and on apoptosis of hepatic cells during liver fibrosis induced by bile duct ligation (BDL). Livers were collected from normal rats, fibrotic rats after 14 and 21 days of BDL, and rats that received BMMNC at 14 days of BDL and were analyzed after 7 days. Apoptosis in fibrogenic cells was analyzed by immunoperoxidase, confocal microscopy, and Western blotting, and liver regeneration was assessed by proliferating cell nuclear antigen staining. Results showed that caspase-3 and proliferating cell nuclear antigen expression were significantly increased in the BMMNC-treated group. Additionally, confocal microscopy analysis showed cells coexpressing α-SMA and caspase-3 in these animals, suggesting fibrogenic cell death. These results suggest a novel role for BMMNC in liver regeneration during fibrotic disease by stimulating fibrogenic cells apoptosis and hepatocyte proliferation, probably through secretion of specific cytokines that modulate the hepatic microenvironment toward an antifibrogenic balance.

Effect evaluation of interleukin-1 receptor antagonist nanoparticles for mesenchymal stem cell transplantation

AIM: To study the efficacy of marrow mesenchymal stem cells (MSCs) transplantation combined with interleukin-1 receptor antagonist (IL-1Ra) for acute liver failure (ALF).

METHODS: Chinese experimental miniature swine were randomly divided into four groups (n = 7), and all animals were given D-galactosamine (D-gal) to induce ALF. Group A animals were then injected with 40 mL saline via the portal vein 24 h after D-gal induction; Group B animals were injected with 2 mg/kg IL-1Ra via the ear vein 18 h, 2 d and 4 d after D-gal induction; Group C received approximately 1 × 10⁸ green fluorescence protein (GFP)-labeled MSCs (GFP-MSCs) suspended in 40 mL normal saline via the portal vein 24 h after D-gal induction; Group D animals were injected with 2 mg/kg IL-1Ra via the ear vein 18 h after D-gal induction, MSCs transplantation was then carried out at 24 h after D-gal induction, and finally 2 mg/kg IL-1Ra was injected via the ear vein 1 d and 3 d after surgery as before. Liver function, serum inflammatory parameters and pathological changes were measured and the fate of MSCs was determined.

RESULTS: The optimal efficiency of transfection (97%) was achieved at an multiplicity of infection of 80, as observed by fluorescence microscopy and flow cytometry (FCM). Over 90% of GFP-MSCs were identified as CD44+ CD90+ CD45- MSCs by FCM, which indicated that most GFP-MSCs retained MSCs characteristics. Biochemical assays, the levels of serum inflammatory parameters and histological results in Group D all showed a significant improvement in liver injury compared with the other groups (P < 0.05). The number of GFP-MSCs in Group D was also greater than that in Group B, and the long-term cell proliferation rate was also better in Group D than in the other groups.

CONCLUSION: MSCs transplantation is useful in ALF, IL-1Ra plays an important role in alleviating the inflammatory condition, and combination therapy with MSCs transplantation and IL-1Ra is a promising treatment for ALF.

Mesenchymal stem cells and Interleukin-6 attenuate liver fibrosis in mice

BACKGROUND

Mesenchymal stem cell (MSC) transplantation has emerged as a promising therapy for liver fibrosis. Issues concerning poor MSC survival and engraftment in the fibrotic liver still persist and warrant development of a strategy to increase MSC potency for liver repair. The present study was designed to examine a synergistic role for Interleukin-6 (IL-6) and MSCs therapy in the recovery of carbon tetrachloride (CCl(4)) induced injured hepatocytes in vitro and in vivo.

METHODS

Injury was induced through 3 mM and 5 mM CCl(4) treatment of cultured hepatocytes while fibrotic mouse model was established by injecting 0.5 ml/kg CCl(4) followed by treatment with IL-6 and MSCs. Effect of MSCs and IL-6 treatment on injured hepatocytes was determined by lactate dehydrogenase release, RT-PCR for (Bax, Bcl-xl, Caspase3, Cytokeratin 8, NFκB, TNF-α) and annexin V apoptotic detection. Analysis of MSC and IL-6 treatment on liver fibrosis was measured by histopathology, PAS, TUNEL and Sirius red staining, RT-PCR, and liver function tests for Bilirubin and Alkaline Phosphatase (ALP).

RESULTS

A significant reduction in LDH release and apoptosis was observed in hepatocytes treated with a combination of MSCs and IL-6 concomitant with upregulation of anti-apoptotic gene Bcl-xl expression and down regulation of bax, caspase3, NFκB and TNF-α. Adoptive transfer of MSCs in fibrotic liver pretreated with IL-6 resulted increased MSCs homing and reduced fibrosis and apoptosis. Hepatic functional assessment demonstrated reduced serum levels of Bilirubin and ALP.

CONCLUSION

Pretreatment of fibrotic liver with IL-6 improves hepatic microenvironment and primes it for MSC transplantation leading to enhanced reduction of liver injury after fibrosis. Synergistic effect of IL-6 and MSCs seems a favored therapeutic option in attenuation of liver apoptosis and fibrosis accompanied by improved liver function.

Mesenchymal stem cells: a revolution in therapeutic strategies of age-related diseases

The great evolutionary biologist Theodosius Dobzhansky once said: "Nothing in biology makes sense except in the light of evolution". Aging is a complex biological phenomenon and the factors governing the process of aging and age-related diseases are only beginning to be understood, oxidative stress, telomere shortening in DNA components and genetic changes were shown to be the mainly regulating mechanisms during the recent decades. Although a considerable amount of both animal and clinical data that demonstrate the extensive and safe use of mesenchymal stromal cells (MSCs) is available, the precise summarization and identification of MSCs in age-related diseases remains a challenge. Along this line, this review discussed several typical age-related diseases for which MSCs have been proved to confer protection and put forward a hypothesis for the association among MSCs and age-related diseases from an evolutionary perspective. Above all, we hope further and more research efforts could be aroused to elucidate the role and mechanisms that MSCs involved in the age-related diseases.

Implication for bone marrow derived stem cells in hepatocyte regeneration after orthotopic liver transplantation

The liver has the outstanding ability to regenerate itself and restore parenchymal tissue after injury. The most common cell source in liver growth/regeneration is replication of preexisting hepatocytes although liver progenitor cells have been postulated to participate in liver regeneration in cases of massive injury. Bone marrow derived hematopoietic stem cells (BM-HSC) have the formal capacity to act as a source for hepatic regeneration under special circumstances; however, the impact of this process in liver tissue maintenance and regeneration remains controversial. Whether BM-HSC are involved in liver regeneration or not would be of particular interest as the cells have been suggested to be an alternative donor source for the treatment of liver failure. Data from murine models of liver disease show that BM-HSC can repopulate liver tissue and restore liver function; however, data obtained from human liver transplantation show only little evidence for liver regeneration by this mechanism. The cell source for liver regeneration seems to depend on the nature of regeneration process and the extent of injury; however, the precise mechanisms still need to be resolved. Current data suggest, that in human orthotopic liver transplantation, liver regeneration by BM-HSC is a rather rare event and therefore not of clinical relevance.

Human liver stem cells improve liver injury in a model of fulminant liver failure

Liver transplantation is currently the only effective therapy for fulminant liver failure, but its use is limited by the scarcity of organs for transplantation, high costs, and lifelong immunosuppression. Here we investigated whether human liver stem cells (HLSCs) protect from death in a lethal model of fulminant liver failure induced by intraperitoneal injection of D-galactosamine and lipopolysaccharide in SCID mice. We show that injection of HLSCs and of HLSC-conditioned medium (CM) significantly attenuates mouse mortality in this model. Histopathological analysis of liver tissue showed reduction of liver apoptosis and enhancement of liver regeneration. By optical imaging we observed a preferential localization of labeled HLSCs within the liver. HLSCs were detected by immunohistochemistry in large liver vessels (at 24 hours) and in the liver parenchyma (after day 3). Fluorescence in situ hybridization analysis with the human pan-centromeric probe showed that positive cells were cytokeratin-negative at 24 hours. Coexpression of cytokeratin and human chromosome was observed at 7 and, to a lesser extent, at 21 days. HLSC-derived CM mimicked the effect of HLSCs in vivo. Composition analysis of the HLSC-CM revealed the presence of growth factors and cytokines with liver regenerative properties. In vitro experiments showed that HLSC-CM protected human hepatocytes from apoptosis and enhanced their proliferation.

CONCLUSION

These data suggest that fulminant liver failure may potentially benefit from treatment with HLSCs or HLSC-CM.

Inhibition of kupffer cell activity improves transplantation of human adipose-derived stem cells and liver functions

Numerous approaches to cell transplantation of the hepatic or the extrahepatic origin into liver tissue have been developed; however, the efficiency of cell transplantation remains low and liver functions are not well corrected. The liver is a highly immunoreactive organ that contains many resident macrophages known as Kupffer cells. Here, we show that the inhibition of Kupffer cell activity improves stem cell transplantation into liver tissue and corrects some of the liver functions under conditions of liver injury. We found that, when Kupffer cells were inhibited by glycine, numerous adipose-derived stem cells (ASCs) were successfully transplanted into livers, and these transplanted cells showed hepatoprotective effects, including decrease of liver injury factors, increase of liver regeneration, and albumin production. On the contrary, injected ASCs without glycine recruited numerous Kupffer cells, not lymphocytes, and showed low transplantation efficiency. Intriguingly, successfully transplanted ASCs in liver tissue modulated Kupffer cell activity to inhibit tumor necrosis factor-α secretion. Thus, our data show that Kupffer cell inactivation is an important step in order to improve ASC transplantation efficiency and therapeutic potential in liver injuries. In addition, the hepatoprotective function of glycine has synergic effects on liver protection and the engraftment of ASCs.

Nitric oxide augments mesenchymal stem cell ability to repair liver fibrosis

Background

Liver fibrosis is a major health problem worldwide and poses a serious obstacle for cell based therapies. Mesenchymal stem cells (MSCs) are multipotent and important candidate cells for future clinical applications however success of MSC therapy depends upon their homing and survival in recipient organs. This study was designed to improve the repair potential of MSCs by transplanting them in sodium nitroprusside (SNP) pretreated mice with CCl₄ induced liver fibrosis.

Methods

SNP 100 mM, a nitric oxide (NO) donor, was administered twice a week for 4 weeks to CCl₄-injured mice. MSCs were isolated from C57BL/6 wild type mice and transplanted in the left lateral lobe of the liver in experimental animals. After 4 weeks, animals were sacrificed and liver improvement was analyzed. Analysis of fibrosis by qRT-PCR and sirius red staining, homing, bilirubin and alkaline phosphatase (ALP) serum levels between different treatment groups were compared to control.

Results

Liver histology demonstrated enhanced MSCs homing in SNP-MSCs group compared to MSCs group. The gene expression of fibrotic markers; αSMA, collagen 1α1, TIMP, NFκB and iNOS was down regulated while cytokeratin 18, albumin and eNOS was up-regulated in SNP-MSCs group. Combine treatment sequentially reduced fibrosis in SNP-MSCs treated liver compared to the other treatment groups. These results were also comparable with reduced serum levels of bilirubin and ALP observed in SNP-MSCs treated group.

Conclusion

This study demonstrated that NO effectively augments MSC ability to repair liver fibrosis induced by CCl₄ in mice and therefore is a better treatment regimen to reduce liver fibrosis.