Historical aspects of hepatocyte transplantation

Bone mesenchymal stem cell transplantation via four routes for the treatment of acute liver failure in rats

In the present study, we assessed the efficiency of four BMSC transplantation methods as a therapy for liver failure. A rat model (80 Sprague-Dawley rats) of D-galactosamine (D-gal)/lipopolysaccharide (LPS)-induced acute liver failure (ALF) was established and the rats were divided into 5 groups: a hepatic artery injection group, a portal vein injection group, a vena caudalis injection group, an intraperitoneal injection group and a control group (16 per group). Following transplantation, the liver tissue and blood samples were collected on days 1, 3 and 7, we detected the EdU (5-ethynyl-2′-deoxyuridine)-labeled cells homing to the liver tissue and assessed the proliferating cell nuclear antigen (PCNA) and cysteine-containing aspartate-specific protease (caspase)-3 expression in the liver tissue and detected the levels of stromal cell-derived factor 1 (SDF-1) and hepatocyte growth factor (HGF) in the liver tissues. Compared with the control group, the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and damage to the liver tissue in the hepatic artery group, the portal vein group and the vena caudalis group improved in vivo. The expression of PCNA and HGF in the liver was higher and caspase-3 expression was lower in the hepatic artery injection group, the portal vein injection group and the vena caudalis injection group than that in the intraperitoneal injection and control groups. The EdU-labeled BMSCs were only observed homing to the liver tissue in these three groups. However, no significant differences were observed between these three groups. Liver function in the rats with ALF was improved following BMSC transplantation via 3 endovascular implantation methods (through the hepatic artery, portal vein and vena caudalis). These 3 methods were effective in transplanting BMSCs for the treatment of ALF. However, the selection of blood vessel in the implantation pathway does not affect the transplantation outcome. Transplantation via intraperitoneal injection showed no therapeutic effect in our animal experiments.

Blockade of endothelial G(i) protein enhances early engraftment in intraportal cell transplant to mouse liver

The limited availability of liver donors and recent progress in cell therapy technologies has centered interest on cell transplantation as a therapeutic alternative to orthotopic liver transplant for restoring liver function. Following transplant by intraportal perfusion, the main obstacle to cell integration in the parenchyma is the endothelial barrier. Transplanted cells form emboli in the portal branches, inducing ischemia and reperfusion injury, which cause disruption of endothelial impermeability and activate the immune system. Approximately 95% of transplanted cells fail to implant and die within hours by anoikis or are destroyed by the host immune system. Intravascular perfusion of Bordetella pertussis toxin (PTx) blocks endothelial G(i) proteins and acts as a reversible inducer of actin cytoskeleton reorganization, leading to interruption of cell confluence in vitro and increased vascular permeability in vivo. PTx treatment of the murine portal vascular tree 2 h before intraportal perfusion of embryonic stem cells facilitated rapid cell engraftment. By 2 h postperfusion, the number of implanted cells in treated mice was more than fivefold greater than in untreated controls, a difference that was maintained to at least 30 days posttransplant. We conclude that prior to cell transplant, PTx blockade of the G(i) protein pathway in liver endothelium promotes rapid, efficient cell implantation in liver parenchyma, and blocks chemokine receptor signaling, an essential step in early activation of the immune system.

Long-term superior performance of a stem cell/hepatocyte device for the treatment of acute liver failure

Cell-based technologies to support/restore organ function represent one of the most promising avenues in the treatment of acute liver failure (ALF). Recently, mesenchymal stem cells (MSCs) have been reported as a new therapeutic for inflammatory conditions. Here, we demonstrate the efficacy of MSCs, when cocultured with hepatocytes, to provide combination hepatic and antiinflammatory therapy in the setting of ALF. MSCs were shown to have multiple beneficial effects in vitro that were relevant in a therapeutic context, including (1) hepatocellular functional support, (2) secretion of molecules that inhibit hepatocyte apoptosis, and (3) modulation of an acute phase response by hepatocytes cultured in ALF-induced serum. In addition, we show that the MSC secretome is dynamically changed in response to serum exposure from ALF rats. We then conducted a therapeutic trial of liver assist devices (LADs). LADs containing cocultures of MSCs and hepatocytes provided a greater survival benefit compared to other coculture and monocellular control LADs. Treatment with MSC-hepatocyte devices was associated with specific improvements in hepatic functional and histological parameters as well as decreasing inflammatory serum cytokine levels, validating a combined therapeutic effect. Moreover, MSC coculture reduced the overall cell mass of the device by an order of magnitude. These findings demonstrate the importance of nonparenchymal cells in the cellular composition of LADs, and strongly support the integration of MSCs into hepatocyte-coculture-based LADs as a potential destination therapy for ALF.