Research on liver regeneration as an answer to the shortage of donors for liver transplantation

VEGF165 gene-modified human umbilical cord blood mesenchymal stem cells protect against acute liver failure in rats

BACKGROUND

Human umbilical cord blood mesenchymal stem cells (HUCB-MSCs) can exert a protective effect in rat models of acute liver failure (ALF). Vascular endothelial growth factor 165 (VEGF₁₆₅ ) is the predominant VEGF isoform and possesses a strong pro-angiogenic function. In the present study, HUCB-MSC served as the gene delivery vehicle for the VEGF₁₆₅ gene, and we explored the therapeutic effects of this system on ALF.

METHODS

HUCB-MSCs were infected with an adenovirus expressing green fluorescent protein (GFP)-VEFG fusion protein (Ad-VEGF₁₆₅ ) to overexpress VEGF₁₆₅ or an adenovirus expressing GFP (Ad-GFP) as control. The control and modified HUCB-MSCs were then transplanted into ALF model rats. Liver function and liver pathological changes were assessed by biochemical tests and liver histology. Immunohistochemistry was carried out to determine the expression of, CD34, Ki67 and VEGF.

RESULTS

VEGF₁₆₅ overexpression enhanced the multipotency of HUCB-MSCs and promoted the homing and colonization of HUCB-MSC in the liver tissues of ALF rats. Furthermore, although HUCB-MSC transplantation ameliorated liver damage and promoted liver regeneration to some extent in ALF rats, Ad-VEGF₁₆₅ -HUCB-MSC transplantation showed stronger therapeutic effects on ALF.

CONCLUSIONS

In summary, transplantation of VEGF₁₆₅ -modified HUCB-MSCs exert stronger therapeutic effects on ALF than HUCB-MSCs. The present study provides a novel therapeutic approach for ALF.

Resina Draconis Reduces Acute Liver Injury and Promotes Liver Regeneration after 2/3 Partial Hepatectomy in Mice

Aim

To investigate the protective effects and possible mechanisms of action of resina draconis (RD) on acute liver injury and liver regeneration after 2/3 partial hepatectomy (PH) in mice.

Methods

2/3 PH was used to induce acute liver injury. Mice were divided into three groups: sham, vehicle + 2/3 PH, and RD + 2/3 PH. Resina draconis was administered intragastrically after 2/3 PH into the RD + 2/3 PH group, and the same volume of vehicle (1% sodium carboxymethyl cellulose) was injected into the vehicle + 2/3 PH group and sham group mice. The index of liver to body weight (ILBW) and proliferating cell nuclear antigen (PCNA) were assayed to evaluate liver regeneration. Blood and liver tissues were collected for serological and western blotting analysis.

Results

Resina draconis protected against 2/3 PH-induced acute severe liver injury and promoted liver regeneration as shown by significantly increased ILBW compared with that of controls. 2/3 PH increased serum AST and ALT levels, which were significantly decreased by RD treatment, while 2/3 PH decreased serum TP and ALB, which were increased by RD treatment. In the RD + 2/3 PH group, PCNA expression was significantly increased compared with the 2/3 PH group. Further, hepatocyte growth factor (HGF), TNFα, and EGFR levels were increased in the RD group at postoperative days 2 and 4 compared with the those in the 2/3 PH group.

Conclusion

Our results suggest that RD ameliorates acute hepatic injury and promotes liver cell proliferation, liver weight restoration, and liver function after 2/3 PH, probably via HGF, TNFα, and EGFR signaling.

Therapeutic effect of human umbilical cord blood mesenchymal stem cells combined with G-CSF on rats with acute liver failure

Human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) have been used to facilitate healing in animal models of liver injury, while granulocyte colony-stimulating factor (G-CSF) has been shown to stimulate stem cell mobilization and these cells may contribute to liver repair. hUCB-MSCs were characterized by flow cytometry, and transplanted into rats with d-galactosamine (D-GalN)/lipopolysaccharides (LPS)-induced acute liver failure (ALF) together with granulocyte colony-stimulating factor (G-CSF). Liver function, oxidative stress and pro-inflammatory cytokines expressions were examined using enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin (HE) staining was used to observe the morphological changes. Apoptosis was investigated by terminal dUTP nick end labeling (TUNEL) staining. Bromodeoxyuridine (BrdU) cell proliferation assay was analyzed by immunofluorescence and immunohistochemistry. In the results, cultured hUCB-MSCs displayed proliferation and adipogenic and osteogenic differentiation potentials. hUCB-MSCs in combination with G-CSF significantly attenuated ALF-induced liver function injury. Furthermore, hUCB-MSCs and G-CSF treatment remarkably suppressed the secretions of pro-inflammatory cytokines and MDA activation induced by ALF. In addition, inflammation, lesions and cell apoptosis in liver tissues were obviously ameliorated by application of hUCB-MSCs and G-CSF. In conclusion, hUCB-MSCs, alone or co-treatment with G-CSF could ameliorate ALF in rats by inhibiting liver function injury, production of pro-inflammatory cytokines, oxidative stress, and liver cell apoptosis.

Generation of fully functional hepatocyte-like organoids from human induced pluripotent stem cells mixed with Endothelial Cells

Despite advances in stem cell research, cell transplantation therapy for liver failure is impeded by a shortage of human primary hepatocytes (HPH), along with current differentiation protocol limitations. Several studies have examined the concept of co-culture of human induced pluripotent cells (hiPSCs) with various types of supporting non-parenchymal cells to attain a higher differentiation yield and to improve hepatocyte-like cell functions both in vitro and in vivo. Co-culturing hiPSCs with human endothelial cells (hECs) is a relatively new technique that requires more detailed studies. Using our 3D human embryoid bodies (hEBs) formation technology, we interlaced Human Adipose Microvascular Endothelial Cells (HAMEC) with hiPSCs, leading to a higher differentiation yield and notable improvements across a wide range of hepatic functions. We conducted a comprehensive gene and protein secretion analysis of our HLCs coagulation factors profile, showing promising results in comparison with HPH. Furthermore, a stage-specific glycomic analysis revealed that the differentiated hepatocyte-like clusters (HLCs) resemble the glycan features of a mature tissue rather than cells in culture. We tested our HLCs in animal models, where the presence of HAMEC in the clusters showed a consistently better performance compared to the hiPSCs only group in regard to persistent albumin secretion post-transplantation.

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.

Clinical Course and Genetic Susceptibility of Primary Biliary Cirrhosis: Analysis of a Prospective Cohort

BACKGROUND

Natural history of primary biliary cirrhosis (PBC) is partially characterized in patients from the Mediterranean area whose genetic background differs from that of Northern Europeans.

OBJECTIVES

We aimed to describe genetic susceptibility and clinical course of PBC in patients from Southern Italy.

METHODS

Socio-demographic, clinical, biochemical and histological data at diagnosis as well as disease progression of 81 PBC consecutive patients were collected. All subjects were treated with Ursodeoxycholic acid at a dose of 15 mg/kg. HLA class II DRB1 alleles were compared with those of 237 healthy control subjects. IL28B genotyping for IL28B rs12979860 C/T and rs80899917 G/T was performed in a sub-group of patients.

RESULTS

HLA-DRB1*07 (RR 5.3, P = 0.0008) and HLA-DRB1*08 (RR n.c. P = 0.0005) were significantly associated with the risk of PBC development. Patients younger than 45 years had significantly higher alanine aminotransferase (P = 0.038) and alkaline phosphatase levels (P = 0.047) than older cases. In comparison to non-CC rs12979860, patients with CC rs12979860 genotype showed an early histological stage at onset (93.8% vs. 62.5%, P = 0.03). After a mean follow-up of 61 months, three patients died, one underwent liver transplantation and sixteen (21.9%) had progression of the disease. At multivariate analysis, extrahepatic autoimmune disease (P = 0.04), pruritus (P = 0.008) and advanced histological stage (P < 0.0001) were independent risk factors for disease progression.

CONCLUSIONS

HLA-DRB1*07 and HLA-DRB1*08 alleles increase susceptibility to disease development. At onset, higher biochemical activity was observed in younger patients, whereas rs12979860 CC genotype was associated with milder histological stage. Pruritus and coexistence of extrahepatic autoimmune diseases were significantly associated with poorer prognosis.

Scalable Differentiation of Human iPSCs in a Multicellular Spheroid-based 3D Culture into Hepatocyte-like Cells through Direct Wnt/β-catenin Pathway Inhibition

Treatment of acute liver failure by cell transplantation is hindered by a shortage of human hepatocytes. Current protocols for hepatic differentiation of human induced pluripotent stem cells (hiPSCs) result in low yields, cellular heterogeneity, and limited scalability. In the present study, we have developed a novel multicellular spheroid-based hepatic differentiation protocol starting from embryoid bodies of hiPSCs (hiPSC-EBs) for robust mass production of human hepatocyte-like cells (HLCs) using two novel inhibitors of the Wnt pathway. The resultant hiPSC-EB-HLCs expressed liver-specific genes, secreted hepatic proteins such as Albumin, Alpha Fetoprotein, and Fibrinogen, metabolized ammonia, and displayed cytochrome P450 activities and functional activities typical of mature primary hepatocytes, such as LDL storage and uptake, ICG uptake and release, and glycogen storage. Cell transplantation of hiPSC-EB-HLC in a rat model of acute liver failure significantly prolonged the mean survival time and resolved the liver injury when compared to the no-transplantation control animals. The transplanted hiPSC-EB-HLCs secreted human albumin into the host plasma throughout the examination period (2 weeks). Transplantation successfully bridged the animals through the critical period for survival after acute liver failure, providing promising clues of integration and full in vivo functionality of these cells after treatment with WIF-1 and DKK-1.

Expression of MicroRNA-155 is Downregulated in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B Patients

BACKGROUND

Persistent hepatitis B virus (HBV) infection is sustained by inadequate immune responses, either natural or acquired. Recent studies have suggested that immune responses to viral infection may be affected by microRNA (miR)-155, via its involvement in immune cell differentiation and maturation. However, little is known on the specific interaction between miR-155 and HBV in host antiviral immunity.

OBJECTIVES

This study evaluated the levels of miR-155 in peripheral blood mononuclear cells (PBMCs) of chronic hepatitis B (CHB) patients, relative to that of healthy subjects, and investigated an association between miR-155 levels and HBV DNA or alanine aminotransferase (ALT).

PATIENTS AND METHODS

Total RNA was extracted from peripheral venous blood samples of 90 treatment-naive patients with chronic HBV infection and 20 healthy volunteers. The levels of miR-155 in the PBMCs were measured by real-time quantitative polymerase chain reaction. Serum HBV DNA and liver enzymes were estimated using standard clinical laboratory methods.

RESULTS

In the HBV-infected patients, the miR-155 levels were significantly lower than in the healthy controls (P = 0.001). Chronic HBV-infected patients with elevated ALT had higher levels of miR-155 compared with patients with normal ALT (P = 0.014). No correlations were found between miR-155 and ALT or HBV DNA.

CONCLUSIONS

The miR-155 appeared to be suppressed during HBV infection. The significantly higher miR-155 levels in ALT-elevated patients infected with HBV suggest that miR-155 levels in PBMCs correlate with the immune state of patients with chronic HBV infection.

Pre-administration of turmeric prevents methotrexate-induced liver toxicity and oxidative stress

BACKGROUND

Methotrexate (MTX) is an antimetabolite broadly used in treatment of cancer and autoimmune diseases. MTX-induced hepatotoxicity limits its application. We investigated hepatoprotective effects of turmeric in MTX-induced liver toxicity.

METHODS

All experiments were performed on male Wistar albino rats that were randomly divided into six groups. Group one received saline orally for 30 days (control group), groups two and three received turmeric extract (100, 200 mg/kg respectively) orally for 30 days, group four received single dose, of MTX IP at day 30, groups five and six received turmeric extract 100 and 200 mg/kg orally respectively for 30 days and single dose of methoterxate IP (20 mg/kg) at day 30. Four days after MTX injection animals were sacrificed and evaluated. Blood ALT and AST (indicators of hepatocyte injury), ALP and bilirubin (markers of biliary function), albumin (reflect liver synthetic function) as well as the plasma TAS concentration (antioxidant defenses) were determined. The cellular antioxidant defense activities were examined in liver tissue samples using SOD, CAT, and GSH-Px for the oxidative stress, and MDA for lipid peroxidation. In addition, liver damage was evaluated histopathologically.

RESULTS

MTX significantly induced liver damage (P<0.05) and decreased its antioxidant capacity, while turmeric was hepatoprotective. Liver tissue microscopic evaluation showed that MTX treatment induced severe centrilobular and periportal degeneration, hyperemia of portal vein, increased artery inflammatory cells infiltration and necrosis, while all of histopathological changes were attenuated by turmeric (200 mg/kg).

CONCLUSION

Turmeric extract can successfully attenuate MTX-hepatotoxicity. The effect is partly mediated through extract's antinflammatory activity.