Stem cells for end stage liver disease: How far have we got?

Functional characterization of CD49f+ hepatic stem/progenitor cells in adult mice liver

Hepatic Stem/progenitor cells (HSPCs) have gained a large amount of interest for treating acute liver disease. However, the isolation and identification of HSPCs are unclear due to the lack of cell-specific surface markers. To isolate adult HSPCs, we used cell surface-marking antibodies, including CD49f and Sca-1. Two subsets of putative HSPCs, Lin^-CD45^-Sca-1^-CD49f⁺ (CD49f⁺) and Lin^-CD45^-Sca-1⁺CD49f^- (Sca-1⁺) cells, were isolated from adult mice liver by flow cytometry. Robust proliferative activity and clonogenic activity were found in both CD49f⁺ and Sca-1⁺ cells through colony-forming tests and cell cycle analyses. Immunofluorescence staining revealed that CD49f⁺ cells expressed ALB and CK-19 while Sca-1⁺ cells expressed only ALB, indicating that CD49f⁺ cells were bipotential and capable of differentiating into hepatocyte and cholangiocyte. Consequently, PAS stain showed that differentiated CD49f⁺ and Sca-1⁺ cells synthesised glycogen, indicating they could differentiate into functional hepatocytes. mRNA expression profile indicated that both CD49f⁺ and Sca-1⁺ cells showed differential expression of genes that are associated with liver progenitor function such as Sox9 and EpCam. Moreover, two subsets of putative HSPCs were activated by DDC and we found that their abundance and proliferation increased with age. In summary, we hypothesized that CD49f⁺ cells were a type of potential HSPCs and may be utilised for clinical stem cell therapy.

Prednisolone and mesenchymal stem cell preloading protect liver cell migration and mitigate extracellular matrix modification in transplanted decellularized rat liver

INTRODUCTION

Regenerative medicine provides promising approaches for treating chronic liver diseases. Previous studies indicate that decellularized liver architecture is damaged by invading non-hepatic inflammatory cells. This study aimed to use anti-inflammatory and regenerative potency of bone marrow-derived mesenchymal stem cells (BM-MSC) and prednisolone for reducing fibrosis and balancing inflammatory cell migration into the decellularized liver scaffold.

MATERIAL AND METHOD

The liver was decellularized by perfusing Sodium Lauryl Ether Sulfate (SLES), and nuclei depletion and extracellular matrix (ECM) retention were confirmed by DNA quantification, histochemical, and immunohistochemical assessments. Scaffolds were loaded with BM-MSCs, prednisolone, or a combination of both, implanted at the anatomical place in the rat partial hepatectomized and followed up for 2 and 4 weeks.

RESULTS

Labeled-MSCs were traced in the transplanted scaffolds; however, they did not migrate into the intact liver. Immunohistochemistry showed that the hepatoblasts, cholangiocytes, stellate, and oval cells invaded into all the scaffolds. Bile ducts were more abundant in the border of the scaffolds and intact liver. Stereological assessments showed a significant reduction in the number of lymphocytes and neutrophils in prednisolone-loaded scaffolds. The regeneration process and angiogenesis were significantly higher in the group treated with cell/prednisolone-loaded bioscaffolds. Collagen fibers were significantly reduced in the scaffolds pre-treated with cell/prednisolone, prednisolone, or BM-MSCs, compared to the control group.

CONCLUSION

Loading prednisolone into the scaffolds can be a worthy approach to restrict inflammation after transplantation. Although pre-loading of the scaffolds with a combination of cells/prednisolone could not alleviate inflammation, it played an important role in regeneration and angiogenesis.

Potentials of Differentiated Human Cord Blood-Derived Unrestricted Somatic Stem Cells in Treatment of Liver Cirrhosis

OBJECTIVES

Liver transplantation is the well-known treatment for chronic liver diseases; however, postoperative complications and lack of donors continue to be limitations with this treatment. Investigating new modalities for treatment of chronic liver illness is a must. In the present study, we aimed to clarify the effects of an in vitro hepatocyte-differentiated human unrestricted somatic stem cell transplant as a new cell-based therapy in an experimental model of chronic liver failure.

MATERIALS AND METHODS

Human umbilical cord blood-derived unrestricted somatic stem cells were isolated, cultured, propagated, and characterized. Cells were directed to differentiate into hepatocyte-like cells. An animal model of carbon tetrachloride cirrhotic liver failure was prepared, and the human in vitro differentiated unrestricted somatic stem cells were transplanted into the experimental model. Animals that did not receive transplant served as the pathologic control group. Animals were euthanized 12 weeks after transplant, and liver functions and histopathology were assessed.

RESULTS

Compared with the pathologic control group, the transplant group showed improvements in levels of alanine aminotransferase, aspartate aminotransferase, albumin, and bilirubin. Histopathologic examination of the transplant group also showed improvements in hydropic degeneration and fibrosis.

CONCLUSIONS

The use of unrestricted somatic stem cells, isolated and propagated from cord blood and then differentiated into hepatocyte-like cells, improved both fibrosis and normal function of cirrhotic livers. These cells could be considered as a line of cell-based therapy in cases of chronic liver disease.

Overexpression of c-Met in bone marrow mesenchymal stem cells improves their effectiveness in homing and repair of acute liver failure

Background

Transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) has emerged as a novel therapy for acute liver failure (ALF). However, the homing efficiency of BMSCs to the injured liver sites appears to be poor. In this study, we aimed to determine if overexpression of c-Met in BMSCs could promote the homing ability of BMSCs to rat livers affected by ALF.

Methods

Overexpression of c-Met in BMSCs (c-Met-BMSCs) was attained by transfection of naive BMSCs with the lenti-c-Met-GFP. The impact of transplanted c-Met-BMSCs on both homing and repair of ALF was evaluated and compared with lenti-GFP empty vector transfected BMSCs (control BMSCs).

Results

After cells were transfected with the lenti-c-Met-GFP vector, the BMSCs displayed very high expression of c-Met protein as demonstrated by Western blot. In addition, in vitro transwell migration assays showed that the migration ability of c-Met-BMSCs was significantly increased in comparison with that of control BMSCs (P < 0.05), and was dependent on hepatocyte growth factor (HGF). Furthermore, rats with ALF that received transplanted c-Met-BMSCs showed significantly improved homing ability to the injured liver; this was accompanied by elevated survival rates and liver function in the ALF rats. Parallel pathological examination further confirmed that transplantation of c-Met-BMSCs ameliorated liver injury with reduced hepatic activity index (HAI) scores, and that the effects of c-Met-BMSCs were more profound than those of control BMSCs.

Conclusions

Overexpression of c-Met promotes the homing of BMSCs to injured hepatic sites in a rat model of ALF, thereby improving the efficacy of BMSC therapy for ALF repair.

Transplant of Hepatocytes, Undifferentiated Mesenchymal Stem Cells, and In Vitro Hepatocyte-Differentiated Mesenchymal Stem Cells in a Chronic Liver Failure Experimental Model: A Comparative Study

OBJECTIVES

Liver transplant is the cornerstone line of treatment for chronic liver diseases; however, the long list of complications and obstacles stand against this operation. Searching for new modalities for treatment of chronic liver illness is a must. In the present research, we aimed to compare the effects of transplant of undifferentiated human mesenchymal stem cells, in vitro differentiated mesenchymal stem cells, and adult hepatocytes in an experimental model of chronic liver failure.

MATERIALS AND METHODS

Undifferentiated human cord blood mesenchymal stem cells were isolated, pro-pagated, and characterized by morphology, gene expression analysis, and flow cytometry of surface markers and in vitro differentiated into hepatocyte-like cells. Rat hepatocytes were isolated by double perfusion technique. An animal model of chronic liver failure was developed, and undifferentiated human cord blood mesenchymal stem cells, in vitro hepato-genically differentiated mesenchymal stem cells, or freshly isolated rat hepatocytes were transplanted into a CCL4 cirrhotic experimental model. Animals were killed 3 months after transplant, and liver functions and histopathology were assessed.

RESULTS

Compared with the cirrhotic control group, the 3 cell-treated groups showed improved alanine aminotransferase, aspartate aminotransferase, albumin, and bilirubin levels, with best results shown in the hepatocyte-treated group. Histopathologic examination of the treated groups showed improved fibrosis, with best results obtained in the undifferentiated mesenchymal stem cell-treated group.

CONCLUSIONS

Both adult hepatocytes and cord blood mesenchymal stem cells proved to be promising candidates for cell-based therapy in liver regeneration on an experimental level. Improved liver function was evident in the hepatocyte-treated group, and fibrosis control was more evident in the undifferentiated mesenchymal stem cell-treated group.

Ultrasound-guided percutaneous portal transplantation of peripheral blood monocytes in patients with liver cirrhosis

BACKGROUND/AIMS

Liver transplantation offers the only definite cure for cirrhosis but lacking donors is problem. Stem cell therapy is attractive in this setting. In this study, we aimed to explore the safety and efficacy of ultrasound-guided percutaneous portal transplantation of peripheral blood monocyte cell (PBMC) in cirrhotic patients.

METHODS

A total of nine decompensated cirrhotic patients were randomized into three groups: group 1 (n = 3) was control group, group 2 (n = 3) received granulocyte-colony stimulating factor (G-CSF) mobilization for 3 days, and group 3 (n = 3) received G-CSF mobilized PBMCs by leukapheresis and PBMC transplantation through ultrasound-guided percutaneous portal vein puncture. Liver function and clinical features were evaluated.

RESULTS

At baseline, the Child-Turcotte-Pugh and the model for end-stage liver disease scores were comparable in study groups. Compared with group 1, there was a tendency to improve liver function in group 3 at 6 months after treatment. Treatment was tolerable and no complications were encountered related to the G-CSF mobilization or percutaneous portal administration of PBMCs. Imaging studies showed patent portal veins at the end of the study period.

CONCLUSIONS

Autologous PBMC transplantation through ultrasound-guided percutaneous portal vein puncture could be considered as a safe alternative treatment for decompensated cirrhotic patients.

Therapeutic Potential of Bone Marrow-Derived Mesenchymal Stem Cells on Experimental Liver Injury Induced by Schistosoma mansoni: A Histological Study

Background and Objectives

Bone marrow derived mesenchymal stem cells (BM-MSCs) have been proposed as effective treatment of many diseases owing to their unique ability to differentiate into other cell types in vivo. Schistosoma mansoni (S. mansoni) infection is characterized by hepatic granuloma formation around schistosome eggs at acute stage of infection, followed by hepatic fibrosis at chronic and advanced stages. Whether BM-MSCs have an ameliorative effect on hepatic tissue injury caused by S. mansoni infection or not, was inspected in the current study.

Materials and Results

Female Swiss Albino mice were divided into a control group and an experimental group. Half of control animals served as donors for bone marrow stem cells, and the other half was used to collect liver samples. Experimental group was injected with circariae of S. mansoni, and then subdivided into three subgroups; Subgroup B1, sacrificed after eight weeks of infection without treatment, subgroup B2, received BM-MSCs at the eighth week and sacrificed four weeks later, and subgroup B3, was untreated till the twelfth week of infection. Histological examination of liver samples showed the formation of granulomas and liver fibrosis which were extensive in subgroup B3. However, treated subgroup illustrated improvement of liver histology, signs of hepatocytes regeneration, and possible contribution of oval cell in the process of hepatic and biliary regeneration.

Conclusion

BM-MSCs decreased liver fibrosis and contributed to an increase in oval cells, generation of new hepatocytes and/or to the improvement of resident hepatocytes in S. mansoni infected mice.

SDF-1/CXCR4 Axis Promotes MSCs to Repair Liver Injury Partially through Trans-Differentiation and Fusion with Hepatocytes

MSCs have become a popular target for developing end-stage liver therapies. In this study, two models of bone marrow chimeric mice were used to construct the liver failure models. Then it was found that MSCs can transdifferentiate into hepatocyte-like cells and these hepatocyte-like cells can significantly express albumin. Furthermore it was also found that MSCs can fuse with the hepatocytes and these cells had the proliferation activity. However, the percentage of transdifferentiation was significantly higher than fusion. So it was considered that MSCs which transdifferentiated into hepatocyte-likes cells played important roles for repairing the injuring liver function.

Isolation of adipose and bone marrow mesenchymal stem cells using CD29 and CD90 modifies their capacity for osteogenic and adipogenic differentiation

Mesenchymal stem cells isolated from rats are frequently used for tissue engineering research. However, considerable differences have been identified between rat mesenchymal stem cells and those derived from humans, and no defined panel of markers currently exists for the isolation of these cells. The aim of this study was to examine the effects of cell sorting for CD29⁺/CD90⁺ cells from rat adipose and bone marrow tissues on their differentiation and expression of stem cell–associated genes. Flow cytometry showed 66% and 78% CD29⁺/CD90⁺ positivity within passage 1 of adipose and bone marrow cultures, respectively. CD29⁺/CD90⁺ cells showed a reduction in both osteogenic and adipogenic differentiation when compared with unsorted cells, as determined by alizarin red and Oil Red-O staining, respectively. These findings could not entirely be explained by fluorescence-activated cell sorting–induced cell injury as sort recovery was only modestly affected in adipose-derived cells. Maintaining cells in fluorescence-activated cell sorting buffer did not affect adipose-derived cell viability, but a significant (p < 0.05) reduction was found in bone marrow–derived cell viability. Additionally, CD29⁺/CD90⁺ selection was associated with a significant decrease in the expression of Lin28, Sox2, Nanog and CD73 in adipose-derived cell cultures, whereas differences in stem cell–associated gene expression were not observed in sorted bone marrow–derived cell cultures. In summary, this study demonstrated that fluorescence-activated cell sorting had differential effects on adipose-derived cells and bone marrow–derived cells, and both CD29⁺/CD90⁺ cells displayed a significantly reduced capacity for osteogenic/adipogenic differentiation. In conclusion, we identify that maintaining heterogeneity within the mesenchymal stem cell population may be important for optimal differentiation.

Stem cells with decellularized liver scaffolds in liver regeneration and their potential clinical applications

End-stage hepatic failure is a potentially life-threatening condition for which orthotopic liver transplantation (OLT) is the only effective treatment. However, a shortage of available donor organs for transplantation each year results in the death of many patients waiting for liver transplantation. Cell-based therapies and hepatic tissue engineering have been considered as alternatives to liver transplantation. However, primary hepatocyte transplantation has rarely produced therapeutic effects because mature hepatocytes cannot be effectively expanded in vitro, and the availability of hepatocytes is often limited by shortages of donor organs. Decellularization is an attractive technique for scaffold preparation in stem cell-based liver engineering, as the resulting material can potentially retain the liver architecture, native vessel network and specific extracellular matrix (ECM). Thus, the reconstruction of functional and practical liver tissue using decellularized scaffolds becomes possible. This review focuses on the current understanding of liver tissue engineering, whole-organ liver decellularization techniques, cell sources for recellularization and potential clinical applications and challenges.

Bone marrow derived stem cells for the treatment of end-stage liver disease

End-stage disease due to liver cirrhosis is an important cause of death worldwide. Cirrhosis results from progressive, extensive fibrosis and impaired hepatocyte regeneration. The only curative treatment is liver transplantation, but due to the several limitations of this procedure, the interest in alternative therapeutic strategies is increasing. In particular, the potential of bone marrow stem cell (BMSC) therapy in cirrhosis has been explored in different trials. In this article, we evaluate the results of 18 prospective clinical trials, and we provide a descriptive overview of recent advances in the research on hepatic regenerative medicine. The main message from the currently available data in the literature is that BMSC therapy is extremely promising in the context of liver cirrhosis. However, its application should be further explored in randomized, controlled trials with large cohorts and long follow-ups.

Ameliorative effect of bone marrow-derived stem cells on injured liver of mice infected with Schistosoma mansoni

The technique of stem cells or hepatocytes transplantation has recently improved in order to bridge the time before whole-organ liver transplantation. In the present study, unfractionated bone marrow stem cells (BMSCs) were harvested from the tibial and femoral marrow compartments of male mice, which were cultured in Dulbecco's modified Eagle's medium (DMEM) with and without hepatocyte growth factor (HGF), and then transplanted into Schistosoma mansoni-infected female mice on their 8th week post-infection. Mice were sacrificed monthly until the third month of bone marrow transplantation, serum was collected, and albumin concentration, ALT, AST, and alkaline phosphatase (ALP) activities were assayed. On the other hand, immunohistopathological and immunohistochemical changes of granuloma size and number, collagen content, and cells expressing OV-6 were detected for identification of liver fibrosis. BMSCs were shown to differentiate into hepatocyte-like cells. Serum ALT, AST, and ALP were markedly reduced in the group of mice treated with BMSCs than in the untreated control group. Also, granuloma showed a marked decrease in size and number as compared to the BMSCs untreated group. Collagen content showed marked decrease after the third month of treatment with BMSCs. On the other hand, the expression of OV-6 increased detecting the presence of newly formed hepatocytes after BMSCs treatment. BMSCs with or without HGF infusion significantly enhanced hepatic regeneration in S. mansoni-induced fibrotic liver model and have pathologic and immunohistopathologic therapeutic effects. Also, this new therapeutic trend could generate new hepatocytes to improve the overall liver functions.

Human induced pluripotent stem cells derived hepatocytes: rising promise for disease modeling, drug development and cell therapy

Recent advances in the study of human hepatocytes derived from induced pluripotent stem cells (iPSC) represent new promises for liver disease study and drug discovery. Human hepatocytes or hepatocyte-like cells differentiated from iPSC recapitulate many functional properties of primary human hepatocytes and have been demonstrated as a powerful and efficient tool to model human liver metabolic diseases and facilitate drug development process. In this review, we summarize the recent progress in this field and discuss the future perspective of the application of human iPSC derived hepatocytes.

Comparison of different methods for the isolation of mesenchymal stem cells from human umbilical cord Wharton's jelly

Several techniques have been devised for the dissociation of tissues for primary culture. These techniques can affect the quantity and quality of the isolated cells. The aim of our study was to develop the most appropriate method for the isolation of human umbilical cord-derived mesenchymal (hUCM) cells. In the present study, we compared four methods for the isolation of hUCM cells: three enzymatic methods; collagenase/hyaluronidase/trypsin (CHT), collagenase/trypsin (CT) and trypsin (Trp), and an explant culture (Exp) method. The trypan blue dye exclusion test, the water-soluble tetrazolium salt-1 (WST-1) assay, flow cytometry, alkaline phosphatase activity and histochemical staining were used to evaluate the results of the different methods. The hUCM cells were successfully isolated by all methods but the isolation method used profoundly altered the cell number and proliferation capacity of the isolated cells. The cells were successfully differentiated into adipogenic and osteogenic lineages and alkaline phosphatase activity was detected in the hUCM cell colonies of all groups. Flow cytometry analysis revealed that CD44, CD73, CD90 and CD105 were expressed in all groups, while CD34 and CD45 were not expressed. The expression of C-kit in the enzymatic groups was higher than in the explant group, while the expression of Oct-4 was higher in the CT group compared to the other groups. We concluded that the collagenase/trypsin method of cell isolation yields a higher cell density than the others. These cells expressed a higher rate of pluripotent cell markers such as C-kit and Oct-4, while the explant method of cell isolation resulted in a higher cell proliferation rate and activity compared to the other methods.

A review on the therapeutic potential of embryonic and induced pluripotent stem cells in hepatic repair

Despite the liver being proliferatively quiescent, it maintains balance between cell gain and cell loss, invokes a rapid regenerative response following hepatocyte loss, and restores liver mass. Human liver has immense regenerative capacity. Liver comprises many cell types with specialized functions. Of these cell types, hepatocytes play several key roles, but are most vulnerable to damage. Recent studies suggest that the extrahepatic stem cell pool contributes to liver regeneration. Stem cell therapies have the potential to enhance hepatic regeneration. Both embryonic and induced pluripotent stem cells could be a suitable source to regenerate hepatocytes. In the present review, we discuss the therapeutic potential of stem cells in hepatic repair and focus on the clinical applications of stem cells.

Use of stem cells for liver diseases-current scenario

End-stage liver disease and liver failure are major health problems worldwide leading to high mortality and morbidity and high healthcare costs. Currently, orthotropic liver transplantation is the only effective treatment available to the patients of end-stage liver disease. However, a serious shortage of liver donors, high cost, and risk of organ rejection are the major obstacles to liver transplantation. Because of the ability of stem cells for differentiation into any tissue type, they have huge potential in therapy of various end-stage or degenerative diseases and traumatic injuries. Stem cell therapy has the potential to provide a valuable adjunct and alternative to liver transplantation and has immense potential in the management of end stage liver disease and liver failure. Stem cell therapy can be mediated by either a direct contribution to the functional hepatocyte population with embryonic, induced pluripotent, or adult stem cells or by promotion of endogenous regenerative processes with bone marrow-derived stem cells. Initial translational studies have been encouraging and have suggested improved liver function in advanced chronic liver disease and enhanced liver regeneration after portal vein embolization and partial hepatic resection. Stem cells infusion in cirrhotic patients has improved liver parameters and could form a viable bridge to transplantation. The present review summarizes basic of stem cell biology relevant to clinicians and an update on recent advances on the management of liver diseases using stem cells.

Therapeutic potentials of mesenchymal stem cells derived from human umbilical cord

Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs), isolated from discarded extra-embryonic tissue after birth, are promising candidate source of mesenchymal stem cells (MSCs). Apart from their prominent advantages in abundant supply, painless collection, and faster self-renewal, hUC-MSCs have shown the potencies to differentiate into a variety of cells of three germ layers (such as bone, cartilage, adipose, skeletal muscle, cardiomyocyte, endothelium, hepatocyte-like cluster, islet-like cluster, neuron, astrocyte and oligodendrocyte), to synthesize and secret a set of trophic factors and cytokines, to support the expansion and function of other cells (like hematopoietic stem cells, embryonic stem cells, natural killer cells, islet-like cell clusters, neurons and glial cells), to migrate toward and home to pathological areas, and to be readily transfected with conventional methods. Two excellent previous reviews documenting the characteristics of this cell population with special emphasis on its niche, isolation, surface markers and primitive properties have been published recently. In this review, we will firstly give a brief introduction of this cell population, and subsequently dwell on the findings of differential capacities with emphasis on its therapeutic potentials.

Rescue of lethal hepatic failure by hepatized lymph nodes in mice

BACKGROUND & AIMS

Hepatocyte transplantation is a potential therapeutic approach for liver disease. However, most patients with chronic hepatic damage have cirrhosis and fibrosis, which limit the potential for cell-based therapy of the liver. The development of an ectopic liver as an additional site of hepatic function represents a new approach for patients with end-stage liver disease. We investigated the development and function of liver tissue in lymph nodes in mice with liver failure.

METHODS

Hepatocytes were isolated from 8- to 12-week-old mice and transplanted by intraperitoneal injection into 8- to 12-week-old fumarylacetoacetate hydrolase mice (Fah(-/-)), a model of the human liver disease tyrosinemia type I. Survival was monitored and the locations and functions of the engrafted liver cells were determined.

RESULTS

Lymph nodes of Fah(-/-) mice were colonized by transplanted hepatocytes; Fah(+) hepatocytes were detected adjacent to the CD45(+) lymphoid cells of the lymphatic system. Ten weeks after transplantation, these mice had substantial improvements in serum levels of transaminases, bilirubin, and amino acids. Homeostatic expansion of donor hepatocytes in lymph nodes rescued the mice from lethal hepatic failure.

CONCLUSIONS

Functional ectopic liver tissue in lymph nodes rescues mice from lethal hepatic disease; lymph nodes therefore might be used as sites for hepatocyte transplantation.

Bone marrow cells obtained from cirrhotic rats do not improve function or reduce fibrosis in a chronic liver disease model

BACKGROUND

The objective of this study was to evaluate the therapeutic potential of bone marrow cells (BMCs) obtained from cirrhotic donors in a model of chronic liver disease.

METHODS

Chronic liver injury was induced in female Wistar rats by the association of an alcoholic diet with intraperitoneal injections of carbon tetrachloride. BMCs obtained from cirrhotic donors or placebo were injected through the portal vein. Blood analysis of alanine aminotransferase (ALT) and albumin levels, ultrasound assessment including the measurement of the portal vein diameter (PVD) and liver echogenicity, histologic evaluation with hematoxylin and eosin and Sirius red staining, and quantification of collagen deposition were performed.

RESULTS

ALT and albumin blood levels showed no significant differences between the experimental groups two months after injection. Additionally, no significant variation in PVD and liver echogenicity was found. Histological analysis also showed no significant variation in collagen deposition two months after placebo or BMC injection.

CONCLUSION

This study suggests that, even though BMC therapy using cells from healthy donors has previously shown to be effective, this is not the case when BMCs are obtained from cirrhotic animals. This result has major clinical implications when considering the use of autologous BMCs from patients with chronic liver diseases.

Transcriptional profiling and hepatogenic potential of acute hepatic failure-derived bone marrow mesenchymal stem cells

Liver stem cell (LSC) transplantation is a promising alternate approach to liver transplantation for patients with end-stage liver disease. However, the precise origin of LSCs remains unclear. Herein we determine if bone marrow mesenchymal stem cells (BMSCs) isolated from rats in acute hepatic failure (AHF) possess hepatic characteristics and have differentiation potential. BMSCs were isolated from AHF and sham-operated rats, and primary hepatocytes were isolated from normal rats for comparison. The transcriptomic profile of BMSCs and primary hepatocytes was analyzed using the Affymetrix GeneChip Rat Genome 230 2.0 Array. BMSCs isolated from AHF and normal rats were induced to differentiate into hepatocytes in vitro and the degree of hepatic differentiation was assessed using quantitative real time RT-PCR, immunohistochemistry, and biochemical assays. AHF-derived BMSCs had a significantly different gene expression profile compared to control BMSCs. Thirty-four gene/probe sets were expressed in both AHF-derived BMSCs and primary hepatocytes, but were absent in control-derived BMSCs, including 3 hepatocyte-specific genes. Forty-four genes were up-regulated more than 2-fold in AHF-derived BMSCs compared to controls, including 3 genes involved in hepatocyte metabolism and development. Furthermore, AHF-derived BMSCs expressed more hepatocyte related genes than control BMSCs. Additional experiments to validate the differentiation of AHF-derived BMSCs, compared to control-derived BMSCs, showed that several hepatocyte-specific genes and proteins [such as albumin (ALB) and alpha fetoprotein (AFP)] were expressed earlier, and at higher levels, after 1 week of differentiation. Hepatocyte-specific metabolic functions were also significantly higher in the AHF group compared to control cells.

CONCLUSION

AHF-derived BMSCs had a hepatic transcriptional profile and expressed hepatocyte specific genes early during differentiation, and possessed greater hepatogenic potency in vitro compared to cells isolated from control animals, further confirming their potential as a stem cell-based therapy for end-stage liver disease.

Stem cell-based therapies for liver diseases: state of the art and new perspectives

Millions of patients worldwide suffer from end-stage liver pathologies, whose only curative therapy is liver transplantation (OLT). Given the donor organ shortage, alternatives to OLT have been evaluated, including cell therapies. Hepatocyte transplantation has been attempted to cure metabolic liver disorders and end-stage liver diseases. The evaluation of its efficacy is complicated by the shortage of human hepatocytes and their difficult expansion and cryopreservation. Recent advances in cell biology have led to the concept of "regenerative medicine", based on the therapeutic potential of stem cells (SCs). Different types of SCs are theoretically eligible for liver cell replacement. These include embryonic and fetal SCs, induced pluripotent cells, annex SCs, endogenous liver SCs, and extrahepatic adult SCs. Aim of this paper is to critically analyze the possible sources of SCs suitable for liver repopulation and the results of the clinical trials that have been published until now.

Progress in stem cell-derived technologies for hepatocellular carcinoma

Primary hepatocellular carcinoma (HCC) is a common malignancy that has a poor prognosis because it is often diagnosed at an advanced stage. HCC normally develops as a consequence of underlying liver disease and is most often associated with cirrhosis. Surgical resection and liver transplantation are the current best options to treat liver cancer. However, problems associated with liver transplantation, such as shortage of donors, risk of immune rejection, and tissue damage following surgery provided the impetus for development of alternative therapies. The emerging field of stem cell therapy has raised hopes for finding curative options for liver cancer. Stem cells have the ability not only to proliferate after transplantation but also to differentiate into most mammalian cell types in vivo. In this review, progress on stem cell-derived technologies for the treatment of liver cancer is discussed.

Could co-transplantation of iPS cells derived hepatocytes and MSCs cure end-stage liver disease?

Orthotopic liver transplantation is, to date, the only proven effective treatment for end-stage liver disease. However, it suffers from lack of donors and immunorejection. Here, we speculate that co-transplantation of induced pluripotent stem (iPS) cells derived hepatocytes and mesenchymal stem cells (MSCs) may offer an alternative way to treat patients with end-stage liver disease. Recently, progress on iPS cells, homogeneous differentiation of hepatocyte-like cells from embryonic stem cells (ESCs), and paracrine effects by MSCs highlight the possibility. Safe, efficient and rapid generation of iPS cells has been reliably produced by several experimental laboratories. Methods for highly efficient and homogeneous differentiation of ESCs into functional hepatocytes have been established as well. Moreover, paracrine effects by MSCs have been proven to play an important role in liver regeneration and repair, and the effects can be used as an enhancer for engraftment. All of these remarkable developments lead to this hypothesis which may offer a novel therapeutic strategy for treatment of patients with end-stage liver disease, though some issues about safety and efficacy need to be further guaranteed.