Comparative proteomics reveals different protein expression in platelets in patients with alcoholic liver cirrhosis.

BACKGROUND: The role of platelets in disease progression as well as the function of platelets as part of the haemostatic and immunological system in patients with liver cirrhosis is only incompletely understood. This is partly due to difficulties in assessing platelet function. Proteome analyses of platelets have been used to further investigate the role of platelets in other diseases. AIM: To assess possible changes in the platelet proteome during different stages of alcohol induced liver cirrhosis compared to healthy donors. PATIENTS AND METHODS: A 45 ml blood sample was drawn from 18 participants aged 18-80 years evenly divided into three groups of healthy donors, patients with less advanced alcohol induced liver cirrhosis (Child-Pugh < 7) and patients with advanced liver cirrhosis (Child-Pugh > 10). The blood was processed to isolate platelets and perform subsequent two-dimensional gel-electrophoresis using a SYPRO™ Ruby dye. After computational analysation significantly in- or decreased protein spots (defined as a two-fold abundance change between different study cohorts and ANOVA < 0.05) were identified via liquid chromatography-mass spectrometry (LCMS) and searching against human protein databases. RESULTS: The comparative analysis identified four platelet proteins with progressively decreased protein expression in patients with liver cirrhosis. More specifically Ras-related protein Rab-7a (Rab-7a), Ran-specific binding protein 1 (RANBP1), Rho GDP-dissociation inhibitor 1 (RhoGDI1), and 14-3-3 gamma. CONCLUSION: There is significant change in protein expression in the platelet proteome throughout the disease progression of alcohol induced liver cirrhosis. The identified proteins are possibly involved in haemostatic and immunoregulatory function of platelets.

Vitamin A deficiency in chronic cholestatic liver disease: Is vitamin A therapy beneficial?

Chronic cholestatic diseases are progressive diseases of the biliary tract that cause hepatic fibrosis and ultimately lead to liver failure. Liver transplantation is the sole curative option currently available, and because of high morbidity and mortality rates of these diseases, new therapeutic approaches are needed. Vitamin A is a nutrient essential for health as it regulates many processes, including epithelial growth and immunological processes. Vitamin A is primarily stored in hepatic stellate cells, and during liver injury, through an unknown mechanism, these cells lose vitamin A and convert into collagen-producing myofibroblasts, which contributes to hepatic fibrosis. Vitamin A deficiencies in chronic cholestatic diseases have been frequently reported, and therefore, retinoid metabolism has attracted a lot of attention. Retinoids have been shown to attenuate or even prevent hepatic fibrosis, and to regulate hepatic immunological response to cholestatic injury in different rodent models of chronic cholestasis. Recently, their potential as therapeutic drugs in primary sclerosing cholangitis patients was analyzed. The aim of this review is to summarize the existing knowledge and hypotheses about vitamin A role and the disease progression in cholestatic liver disease.

The MBOAT7 rs641738 variant is associated with an improved outcome in primary sclerosing cholangitis.

BACKGROUND AND AIMS: Primary sclerosing cholangitis (PSC) is a chronic cholestatic disease that causes liver cirrhosis, leading to liver failure. Additionally, PSC is a risk factor for cholangiocarcinoma. Its mechanism is unknown, and liver transplantation remains the sole curative option. The membrane bound O-acyltransferase domain containing 7 (MBOAT7) rs641738 and rs626283 variant alleles have been associated with both an accelerated progression of the disease and a higher risk for developing a more severe phenotype in many chronic hepatic diseases. Thus, we analysed their effect on long-term outcomes and laboratory parameters in PSC patients. METHODS: We determined MBOAT7 genotypes and estimated the actuarial survival rate free of liver transplantation, using the Kaplan-Meier estimator. The differences between the estimates were analysed using the log-rank test. Patient blood was drawn and analysed for different serum parameters including cholestatic markers. Additionally, MBOAT7 RNA expression in human hepatic cell lines MZCHA1 (a biliary adenocarcinoma cell line), HepG2 (a hepatocellular carcinoma cell line), LX-2 (hepatic stellate cell line) and H-69 (cholangiocyte cell line) was analysed. RESULTS: Transplant-free survival was significantly prolonged in carriers of two rs641738 variant alleles, which was referred to as the TT genotype (mean 19.6 years; 95% confidence interval [CI]: 16.3-22.9 years) compared to the CC (mean 15.4 years, 95% CI 12.8-18.0 years) and heterozygous genotypes (mean 13.2 years, 95% CI 11.4-15.0 years) (P=0.017). This effect was restricted to male patients. We confirmed the high expression of MBOAT7 in hepatic stellate cells and found that MBOAT7 is less expressed in biliary epithelial cell lines, compared to parenchymal hepatic cells. CONCLUSIONS: Unlike other chronic liver diseases, carrying two MBOAT7 variant alleles does not seem to affect PSC patients negatively, but seems to have a positive effect on transplant-free survival. This study could help improve individual prognosis in PSC patients and give some new perspective on the involvement of the immune system in PSC.