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.