Human Liver-derived Stem Cells Research Articles

Hepatogenic Potential and Liver Regeneration Effect of Human Liver-derived Mesenchymal-Like Stem Cells.

Human liver-derived stem cells (hLD-SCs) have been proposed as a possible resource for stem cell therapy in patients with irreversible liver diseases. However, it is not known whether liver resident hLD-SCs can differentiate toward a hepatic fate better than mesenchymal stem cells (MSCs) obtained from other origins. In this study, we compared the differentiation ability and regeneration potency of hLD-SCs with those of human umbilical cord matrix-derived stem cells (hUC-MSCs) by inducing hepatic differentiation. Undifferentiated hLD-SCs expressed relatively high levels of endoderm-related markers (GATA4 and FOXA1). During directed hepatic differentiation supported by two small molecules (Fasudil and 5-azacytidine), hLD-SCs presented more advanced mitochondrial respiration compared to hUC-MSCs. Moreover, hLD-SCs featured higher numbers of hepatic progenitor cell markers on day 14 of differentiation (CPM and CD133) and matured into hepatocyte-like cells by day 7 through 21 with increased hepatocyte markers (ALB, HNF4A, and AFP). During in vivo cell transplantation, hLD-SCs migrated into the liver of ischemia-reperfusion injury-induced mice within 2 h and relieved liver injury. In the thioacetamide (TAA)-induced liver injury mouse model, transplanted hLD-SCs trafficked into the liver and spontaneously matured into hepatocyte-like cells within 14 days. These results collectively suggest that hLD-SCs hold greater hepatogenic potential, and hepatic differentiation-induced hLD-SCs may be a promising source of stem cells for liver regeneration.

Human Liver-Derived Stem Cells Improve Fibrosis and Inflammation Associated with Nonalcoholic Steatohepatitis.

Cell therapy may be regarded as a feasible alternative to whole organ transplantation to treat end-stage liver diseases. Human liver stem cells (HLSCs) are a population of cells easily obtainable and expandable from a human adult liver biopsy. HLSCs share with mesenchymal stromal cells the same phenotype, gene expression profile, and differentiation capabilities. In addition, HLSCs show a specific commitment to the hepatic phenotype. Injection of HLSCs into immunodeficient mice fed with a methionine-choline-deficient diet to induce nonalcoholic steatohepatitis ameliorates liver function and morphology. In particular, HLSC treatment induced a reduction of liver fibrosis and inflammation at morphological and molecular levels. Moreover, HLSCs were able to persist for up to 3 weeks after the injection. In conclusion, HLSCs have healing effects in a model of chronic liver disease.

Protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A-induced acute liver injury in mice

Objective: To investigate the protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A (ConA)-induced acute liver injury in mice. Methods: A total of 88 male C57BL/6 mice were randomly divided into normal control group (group C), ConA model group (group M), and human liver-derived stem cells (HYX1)+ConA group (group E); according to the interval between phosphate buffer/HYX1 injection and ConA injection, Groups M and E were further divided into 3-hour groups (M1 and E1 groups), 6-hour groups (M2 and E2 groups), 12-hour groups (M3 and E3 groups), 24-hour groups (M4 and E4 groups), and 48-hour groups (M5 and E5 groups). The levels of alanine aminotransferase (ALT), aspartate transaminase (AST), and total bilirubin (TBil) in peripheral blood were measured, liver tissue sections were used to observe pathological changes, and the Ishak score for liver inflammation was determined. The independent samples t-test was used for comparison between groups, and P < 0.05 was considered statistically significant. Results: The levels of ALT, AST, and TBil in group C were (36.25±1.16) U/L, (120.20±5.77) U/L, and (2.20±0.23) μmol/L, respectively; the levels of ALT, AST, and TBil and Ishak score were (8 721.23±837.39) U/L, (8 110.31±290.10) U/L, (8.41±0.10) μmol/L, and (13.32±1.30), respectively, in group M1, (8 334.31±666.50) U/L, (7 560.20±760.34) U/L, (10.40±0.80) μmol/L, and (12.67±0.81), respectively, in group M2, (8 960.75±551.93) U/L, (8 535.62±675.14) U/L, (10.95±1.43) μmol/L, and (14.57±0.65), respectively, in group M3, (8 618.57±886.40) U/L, (11 440.54 ± 1 327.86) U/L, (13.30±1.86) μmol/L, and (13.21±1.06), respectively, in group M4, and (10 170.13±1 112.37) U/L, (11 470.56±1 108.40) U/L, (12.75±1.55) μmol/L, and (15.07±1.58), respectively, in group M5. The levels of ALT, AST, and TBil and Ishak score were (1 016.35±163.47) U/L, (952.30±103.91) U/L, (7.77±0.62) μmol/L, and (3.50±0.21), respectively, in group E1, (42.10±6.20) U/L, (126.72±13.33) U/L, (3.41±0.53) μmol/L, and (2.01±0.40), respectively, in group E2, (44.21±4.30) U/L, (216.71±35.88) U/L, (3.47±0.44) μmol/L, and (2.13±0.25), respectively, in group E3, (2 909.69±212.14) U/L, (2 988.43±333.70) U/L, (7.03±0.93) μmol/L, and (4.70±0.50), respectively, in group E4, and (7 874.26±799.60) U/L, (10 940.54±947.35) U/L, (10.53±1.09) μmol/L, and (8.60±0.83), respectively, in group E5. Groups M1-M5 had significantly higher levels of ALT, AST, and TBil than group C (all P < 0.01), and groups M1-M4 had significantly higher levels of AST and ALT than groups E1-E4 (all P < 0.01), while there were no significant differences in the levels of AST and ALT between groups M5 and E5 (both P > 0.05). The pathological sections of liver tissue showed that compared with group M, group E had significant reductions in the degree of necrosis and Ishak score (both P < 0.05). Conclusion: Intraperitoneal transplantation of human liver-derived stem cells has a protective effect against ConA-induced acute liver injury in mice, and the injection at 6 and 12 hours in advance has the best protective effect.

Suppression of T-Cell Proliferation by and B7-H1 Expression on Human Liver-Derived Stem Cells

BackgroundMany types of stem cells have been widely used for the treatment of liver diseases. The therapeutic effect of stem cells is predominantly based on the immune regulatory properties of these cells. MethodsWe isolated human liver stem cells (HLSCs), which are considered intrahepatic stem cells, and examined their suppression of T-cell proliferation induced by phytohemagglutinin. ResultsHLSCs inhibited phytohemagglutinin-induced T-cell proliferation not only in direct co-culture but also in indirect co-culture in a cell number–dependent manner. That is, T-cell proliferation was substantially inhibited by cell-to-cell contact regardless of soluble factor(s). B7-H1, a co-inhibitory molecule that relies on cell-to-cell contact, was found to be constitutively expressed at low levels on HLSCs. Furthermore, its expression was upregulated moderately by tumor necrosis factor-α and dramatically by interferon-γ. ConclusionsThese results suggest that HLSCs would have therapeutic effects through T-cell suppression in acute liver diseases.

In Vitro Differentiation of Human Liver-derived Stem Cells with Mesenchymal Characteristics into Immature Hepatocyte-like Cells

Liver transplantation is severely limited by donor shortage although it is the only effective treatment for end-stage liver disease. So the best alternative is hepatocyte transplantation. For obtaining human hepatocytes, some stem cells originating from extrahepatic or intraheptic tissues have been isolated and characterized. Previously we have reported that human liver-derived stem cells (HLSCs) could be isolated and expanded from donated livers unsuitable for transplantation; they expressed some markers of mesenchymal stem cells but neither hematopoietic nor oval cells. In this study, we isolated and expanded HLSCs with mesenchymal characteristics from another adult human liver. They showed mesenchymal morphology and grew well under serum condition similar to our previous reports. Also, they expressed some markers of mesenchymal stem cells, such as CD44, CD73, CD90, and CD105, through fluorescence-activated cell sorting analysis. When HLSCs were sequentially exposed to fibroblast growth factor−1 (FGF-1), FGF-4, and hepatocyte growth factor (HGF) followed by FGF-4, HGF, oncostatin M, and dexamethasone, they became round or polygonal, and expressed some hepatic markers such as albumin and α1-antitrypsin in the gene or protein level. Also, they showed urea synthesis activity 7 days after treatment of FGF-4, HGF, oncostatin M, and dexamethasone. These results provided that HLSCs would be a useful cell source in the field of regenerative medicine as well as liver cell biology.

Differentiation and Major Histocompatibility Complex Antigen Expression in Human Liver–Derived Stem Cells

Stem cells are a promising source for liver repopulation after cell transplantation, but whether the adult liver contains hepatic stem cells is controversial. The purpose of this study was to characterize the properties and expression profile of major histocompatibility complex (MHC) antigens on the surface of human-derived stem cells. Human liver–derived stem cells (HLSC7) were isolated from the nontumorous tissue of a patient who underwent a resection of an hepatic hemangioendothelioma. We characterized HLSC7 using a fluorescence-activated cell sorter, polymerase chain reactions, and immunofluorescence assays. HLSC7 expressed mesenchymal but not hematopoietic stem cell markers. HLSC7 underwent osteogenic, chondrogenic, and hepatogenic differentiation when cultured in appropriate differentiation media. However, HLSC7 did not differentiate into adipocytes. In addition, HLSC7 did not express MHC class II (HLA-DP, -DQ, and -DR) antigens. However, they did express MHC class I antigens. These results suggest that human liver–derived stem cells express MHC class I antigens and thus may be rejected on transplantation. Therefore, in addition to studies on stem cell differentiation, one must overcome immunologic barriers for successful clinical application of this therapy.

Human liver-derived stem cells.

The search for human oval cells or bi-potential stem cells in the human liver is the subject of intensive investigation. Fetal hepatocytes (hepatoblasts) have some proliferative and bipotential capacity, but access to sufficient numbers of cells remains limiting. Candidate stem cells in the adult normal and diseased human liver have been identified using markers such as OV6, CD34, c-kit and NCAM. Lack of stem cell marker specificity however, remains a problem and further, more specific markers are required. The molecular signaling molecules and transcription factors that control proliferation and cell differentiation pathways into hepatocyte or biliary phenotype are beginning to emerge. However, whether any of the current liver stem cell approaches will be converted into effective clinical cell transplantation or gene therapy treatments has yet to be proven.