Activation of hepatic stellate cells in liver tissue of patients with fulminant liver failure after treatment with bioartificial liver

Randomized Trial of Spheroid Reservoir Bioartificial Liver in Porcine Model of Posthepatectomy Liver Failure

Acute liver failure (ALF) is a catastrophic condition that can occur after major liver resection. The aim of this study was to determine the effects of the spheroid reservoir bio-artificial liver (SRBAL) on survival, serum chemistry, and liver regeneration in posthepatectomy ALF pigs. Wild-type large white swine (20 kg-30 kg) underwent intracranial pressure (ICP) probe placement followed by 85% hepatectomy. Computed tomography (CT) volumetrics were performed to measure the extent of resection, and at 48 hours following hepatectomy to assess regeneration of the remnant liver. Animals were randomized into three groups based on treatment delivered 24-48 hours after hepatectomy: Group1-standard medical therapy (SMT, n = 6); Group2-SMT plus bio-artificial liver treatment using no hepatocytes (0 g, n = 6); and Group3-SMT plus SRBAL treatment using 200 g of primary porcine hepatocyte spheroids (200 g, n = 6). The primary endpoint was survival to 90 hours following hepatectomy. Death equivalent was defined as unresponsive grade 4 hepatic encephalopathy or ICP greater than 20 mmHg with clinical evidence of brain herniation. All animals in both (SMT and 0 g) control groups met the death equivalent before 51 hours following hepatectomy. Five of 6 animals in the 200-g group survived to 90 hours (P < 0.01). The mean ammonia, ICP, and international normalized ratio values were significantly lower in the 200-g group. CT volumetrics demonstrated increased volume regeneration at 48 hours following hepatectomy in the 200-g group compared with the SMT (P < 0.01) and 0-g (P < 0.01) groups. Ki-67 staining showed increased positive staining at 48 hours following hepatectomy (P < 0.01). Conclusion: The SRBAL improved survival, reduced ammonia, and accelerated liver regeneration in posthepatectomy ALF. Improved survival was associated with a neuroprotective benefit of SRBAL therapy. These favorable results warrant further clinical testing of the SRBAL.

Systematic review: extracorporeal bio-artificial liver-support system for liver failure

BACKGROUND

Orthotopic liver transplantation (OLT) is the only effective long-term treatment for liver failure by now. However, it is not yet a perfect choice due to donor-organ shortage and the need of a lifelong immunosuppressive therapy. Therefore, it is necessary to find a new approach to fighting the disease. Several published clinical trials have reported the therapeutic effect of bio-artificial liver (BAL) for liver failure.

OBJECTIVE

To overview and evaluate the current clinical application and outcomes of extracorporeal BAL support system during the past 15 years.

METHODS

Relevant studies were retrieved from PubMed and Cochrane Library databases. Independent assessments and the final consensus decision were performed by three independent reviewers. Acceptable study designs included randomized controlled trials, controlled clinical trials, and case reports. A total of 31 studies were tabulated and critically appraised in terms of characteristics, methods, and outcomes.

RESULTS

There was a trend of falling into the normal ranges with the clinical and biochemical parameters after the BAL treatment. The neurological status of most patients was improved or stabilized during BAL treatment as well. No significant effect on survival could be seen after the BAL treatment.

CONCLUSIONS

Although BAL system proved to be a success in some clinical cases reported, it still needs to be improved greatly.

Distinct mechanism of small-for-size fatty liver graft injury--Wnt4 signaling activates hepatic stellate cells

In this study, we aimed to investigate the significance of hepatic stellate cells (HSCs) activation in small-for-size fatty liver graft injury and to explore the underlying molecular mechanism in a rat liver transplantation model. A rat orthotopic liver transplantation model using fatty grafts (40% of fatty changes) and cirrhotic recipients was applied. Intragraft gene expression profiles, ultrastructure features and HSCs activation were compared among the rats received different types of grafts (whole vs. small-for-size, normal vs. fatty). The distinct molecular signature of small-for-size fatty graft injury was identified by cDNA microarray screening and confirmed by RT-PCR detection. In vitro functional studies were further conducted to investigate the direct effect of specific molecular signature on HSCs activation. HSCs activation was predominantly present in small-for-size fatty grafts during the first 2 weeks after transplantation, and was strongly correlated with progressive hepatic sinusoidal damage and significant upregulation of intragraft Wnt4 signaling pathway. In vitro suppression of Wnt4 expression could inhibit HSC activation directly. In conclusion, upregulation of Wnt4 signaling led to direct HSC activation and subsequently induced small-for-size fatty liver grafts injury. Discovery of this distinct mechanism may lay the foundation for prophylactic treatment for marginal graft injury in living donor liver transplantation.

Hepatic Stellate Cells in Biopsies From Liver Allografts With Acute Rejection

BACKGROUND

[corrected] Hepatic stellate cells (HSCs) are nonparenchymal elements that play a major role in fibrogenesis due to various pathologies. HSCs are easily activated by certain injuries, which produce contraction and relaxation of HSCs, resulting in hepatic microcirculatory disturbances. The present study sought to analyze the expression of alpha-smooth muscle actin (alpha-SMA) positive HSCs in liver allografts during acute rejection episodes (ARE), determining whether it was related to the pathogenesis of this immune response.

MATERIALS AND METHODS

Using immunohistochemistry and a semiquantitative scoring system, the expression of alpha-SMA in HSCs was analyzed in liver allografts with ARE (group 1, n = 64) or without ARE (group 2, n = 20). Normal liver tissue from transplant donors (group 3, n = 53) served as the control materials.

RESULTS

Significantly more alpha-SMA positive HSCs were found in group 2 than in the other two groups (P < .05). The minimal difference observed between groups 1 and 3 was not statistically significant. As well, no statistical association was found between expression of alpha-SMA and the clinical parameters of age, gender, etiology of liver failure, donor type (partial or whole), posttransplantation period, and liver function tests.

CONCLUSIONS

While these results represent preliminary findings, it may be possible that HSC expression is a protective mechanism during ARE in hepatic allograft patients. If this is true, enhanced expression of this protein may mitigate ARE in liver allograft patients.