Western blotting analysis for quantitative detection of CYP2C19 expression in liver tissues in the setting of living donor liver transplantation

Background: The cytochrome P450 (CYP) drug-metabolizing enzymes play an important role in cellular metabolism. Therapeutic failure or drug toxicity in the period after liver transplantation (LT) is influenced by the drug metabolizing capacity of the graft. The expression levels of CYP2C19 enzyme are often used as an indicator of the functioning of the CYP system. The aim of the present study was to assess the CYP2C19 protein expression in the setting of living donor liver transplantation (LDLT) by using western blotting analysis. Methodology: We performed CYP2C19 genotyping of liver biopsy samples obtained from 24 donors and 8 recipients each in the pre- and post-LT periods, after which we analyzed the CYP enzyme activity by using western blotting analysis. Results: The CYP2C19/β-actin ratio, which was an indicator of CYP expression, was 61.75% (23-100%) in donors, 59.13% (15-100%) in pre-LT recipients and 46.71% (12-67%) in post-LT recipients (p>0.05). The CYP2C19 expression levels associated with different genotypes were as follows: homozygous extensive metabolizers (HomEMs; n=24), 56.63±24.74%; heterozygous extensive metabolizers (HetEMs; n=15), 63.0±25.14% and poor metabolizers (PMs; n=1), 82.0% (p>0.05). Conclusions: Western blotting analysis showed low CYP2C19 protein expression not only in samples from the pre- and post-LT recipients but also from the donors.