Cyclosporin A Inhibits Albumin Synthesis in Huh7 Cells

BACKGROUND/AIMS Hypoalbuminemia occurs frequently in renal transplant recipients immediately after renal transplantation. We studied the regulation of hepatic albumin synthesis by cyclosporin A (CsA) in Huh7 cells. METHODS Huh7 cells were incubated with various concentrations of CsA for 4, 8, 16, and 24 hours. Albumin was measured in Huh7 cell-conditioned medium by sandwich enzyme-linked immunosorbent assay and Western blot. Albumin mRNA expression was analyzed by Northern blotting in CsA-treated cells. RESULTS CsA (10(-7)-10(-4) M) inhibited albumin synthesis in Huh7 cells in a dose- dependent manner. A Western blot analysis for albumin in the conditioned medium released from CsA-treated (10(-7)-10(-5) M) cells also showed significant inhibition of albumin synthesis in a dose-dependent manner. Vehicle (olive oil) did not affect albumin synthesis. In contrast, a Northern blot analysis revealed no inhibition of albumin mRNA expression by CsA at any time point from 1-24 hours, indicating that the inhibition of albumin synthesis occurred at the translational level. CONCLUSIONS Our results suggest that inhibition of hepatic albumin synthesis by high dose CsA contributes to the hypoalbuminemia in renal transplant recipients.