Bone marrow stem cell therapy for liver disease

Substance-P prevents the cholestatic liver injury by regulating inflammatory responses

Substance-P (SP) is a neuropeptide that modulates immune responses and accelerates tissue repair in critical inflammatory disease. Liver fibrosis and cirrhosis are the ultimate outcomes of almost all chronic liver diseases caused by viral infection, steatohepatitis, autoimmune, and cholestatic injury. Despite the development of new drugs, liver transplantation is still the only fundamental treatment; thus, new therapeutic approaches to mitigate liver fibrosis and chronic inflammation are constantly being needed. The aim of this study was to examine the effect of SP on liver damage due to cholestatic stress. To induce cholestatic injury, common bile duct ligation (CBDL) was attempted, followed by systemic application of SP. SP treatment increased IL-10 and decreased TNF-α in serum with increasing levels of circulating regulatory T cells (Tregs) from the early stage of CBDL. Moreover, SP decreased CBDL-induced TGF-β1 expression in the circulation. This could create anti-inflammatory/anti-fibrotic environment under CBDL, which might ameliorate the progression of liver fibrosis in CBDL. Histological and molecular analysis revealed that SP treatment reduced ductular reaction, hepatic damage, and apoptotic hepatocytes, accompanied by diminishing type I collagen and upregulating MMP-9. These studies found that SP is a promising therapeutic candidate for immune-related liver disease as well as cholestatic liver disease, by providing hepatic protective effects via immune suppression.

Long-term Production of Glycogen and Hepatic-Derived, Cell-Invasion-Promoting Chemokines by Ultrasound-Driven Hepatic-Differentiated Human Bone Marrow Mesenchymal Stem Cells

The current treatment for liver failure is restricted to surgical liver transplantation, which is technically complicated, limited by the shortage of available organs and presents major risks to the patient. Bone marrow mesenchymal stem cells (BMSCs) represent promising sources of hepatocyte-like cells for cell transplantation treatment. However, a safe and efficient induction method for their differentiation remains to be defined. Here we further optimized an effective technique by combining high-dose treatment with hepatocyte growth factor (HGF) and ultrasound stimulation. The optimized ultrasound parameter (1.0 W/cm² intensity, 1 MHz frequency, 20% duty cycle, 100 Hz pulse repetition frequency, 60-s irradiation duration, triple times in three days) combined with different HGF doses (10, 20 and 50 ng/ml) was used to treat BMSCs. The results showed that the specific hepatic markers, including α-fetoprotein (αFP/AFP), cytokeratin 18 (CK18), albumin (ALB) and glycogen, were increased in a dose-dependent manner. Their concentration was then further increased when ultrasound irradiation was administered (P < 0.05), as indicated by PCR, Western blot and immunofluorescence staining as well as a glycogen synthesis test. Furthermore, analysis of the hepatocyte-derived chemokines showed elevated stromal cell-derived factor 1alpha (SDF-1α) and C-X-C chemokine receptor type 4 (CXCR4) after HGF treatment. Again, concentrations of those chemokines were further increased by ultrasound radiation (P < 0.05). The observed increased effect was sustained for 21 days. To summarize, we further defined the optimal combination of HGF and ultrasound treatment to increase the differentiation and chemotaxis of BMSCs in a safe, sustained and efficient manner. These findings provide a new perspective for stem cell orientation in the field of tissue engineering.

Ultrasound Irradiation Combined with Hepatocyte Growth Factor Accelerate the Hepatic Differentiation of Human Bone Marrow Mesenchymal Stem Cells

This study investigated the impact of ultrasound (US) irradiation on the hepatic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) induced by hepatocyte growth factor (HGF) and the possible mechanisms. We treated hBMSCs, using HGF with and without US irradiation. Cell viability and stem cell surface markers were analyzed. Hepatocyte-like cell markers and functional markers including α-fetoprotein (αFP/AFP), cytokeratin 18 (CK18), albumin (ALB) and glycogen content were analyzed at the time point of day 1, 3 and 5 after treatment. The involvement of Wnt/β-catenin signaling pathway was evaluated as well. The results showed that the US treatment at 1.0 W/cm² or 1.5 W/cm² for 30 s or 60 s conditions yielded favorable cell viability and engendered stem cell differentiation. At day 5, the expressions of AFP, CK18, ALB and the glycogen content were significantly elevated in the US-treated group at both messenger ribonucleic acid and protein levels (all p <0.05), in comparison with HGF and control groups. Among all the US treated groups, the expression levels of specific hepatic markers in the (1.5 W/cm² for 60 s) group were the highest. Furthermore, Wnt1, β-Catenin, c-Myc and Cyclin D1 were significantly increased after US irradiation (all p <0.05), and the enhancements of c-Myc and Cyclin D1 could be obviously impaired by the inhibitor ICG-001 (p <0.05, p <0.05), in accordance with decreased ALB and CK18 expression and glycogen content (all p <0.05). In conclusion, US irradiation was able to promote the hBMSCs' differentiation mediated by HGF in vitro safely, easily and controllably. The activation of Wnt/β-catenin signaling pathway was involved in this process. US irradiation could serve as a potentially beneficial tool for the research and application of stem cell differentiation.

BMSCs protect against liver injury via suppressing hepatocyte apoptosis and activating TGF-β1/Bax singling pathway

Many factors cause liver injury, including chronic consumption of alcohol, irregular use of drugs, excessive levels of arsenic in water. This study aims to investigate role of bone marrow-derived mesenchymal stem cells (BMSCs) in liver injury recovery and to explore mechanism. BMSCs and primary hepatocytes were isolated, cultured and identified. Hepatocyte model and hepatic fibrosis (HF) model were established using carbon tetrachloride (CCL-4). The role of BMSCs were investigated in both in vitro and in vivo levels. Cell proliferation was examined using MTT assay. Transforming growth factor-β1 (TGF-β1), Bcl-2 and Bax expression were detected using western blot and real-time PCR, respectively. Results indicated that BMSCs and primary hepatocytes were successfully isolated and identified, and hepatocyte model was successfully established. BMSCs and HGF treatment enhance viability of normal hepatocytes and hepatocyte injury model. Cell viability in BMSCs treatment and Bax-1 inhibitor treatment group was higher significantly compared to normal hepatocyte control and injury hepatocyte model, respectively (P<0.05). Bax-1 expression was significantly lower and Bcl-2 was significantly higher in Bax-1 inhibitor treatment and BMSCs treatment group compared to normal hepatocyte control (normal rats) and injury hepatocyte model (HF model), respectively (P<0.05). BMSCs significantly decreased ALT and AST levels compared to Saline group (P<0.05). In conclusion, function of BMSCs in liver injury was triggered by inhibiting hepatocyte apoptosis and leading cell proliferation through TGF-β1/Bax singling pathway. Our study proved protective role of BMSCs against liver injury via TGF-β1/Bax pathway, which would enrich application of BMSC in clinical.

Stem cell based therapies for liver diseases: Current status and perspectives

The clinical applications of stem cells have attracted wide attention for years. Stem cells could be used to treat many diseases, such as nervous diseases, diabetes mellitus, kidney disease, liver diseases, and cancer. There have been many reports about the applications of stem cells in liver diseases, although there are still many problems. Stem cell based therapies will emerge as a promising option for the treatment of liver diseases.

Progress in research of hepatic stem cells

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. There is currently a clear need for new therapies for liver disease, and it is possible that hepatic stem cell (HSC) therapy represents an exciting new therapeutic option. HSCs are undifferentiated cells with the unique ability to self-renew and potentially provide a source of human hepatocytes for regeneration of the injured liver. Evidence from pre-clinical studies is encouraging, but conclusive evidence that this translates into humans remains lacking. Further studies of the mechanisms responsible for the beneficial effects of HSC therapy are needed.