Effect of tacrolimus and cyclosporine A on suppression of albumin secretion induced by inflammatory cytokines in cultured human hepatocytes.

OBJECTIVE AND DESIGN

To investigate the effect of tacrolimus (FK506) and cyclosporine A (CSA) on albumin secretion and on the IL-6 -induced suppression of albumin synthesis in cultured human hepatocytes.

METHODS

HepG2 cells were cultured separately with IL-6, IL-10 (0-10 ng/ml) and FK506, CSA (0-100 ng/ml) for 48 h. In another experiment, HepG2 cells were incubated with different amounts of FK506 and CSA (0-10 ng/ml) in the presence of IL-6 (5 ng/ml). The albumin levels in these groups of hepatic cultures were measured by radioimmunoassay. The concentration of LDH secreted by cells stimulated with FK506 and CSA was detected by spectrophotometry.

RESULTS

IL-6 decreased the levels of albumin in a dose-dependent manner (P < 0.01), maximal inhibition was observed at 5 ng/ml. Neither IL-10 nor FK506 modulated albumin production. However, FK506 decreased LDH levels in the supernatant of cells (P < 0.05) and prevented the IL-6-induced suppression of albumin synthesis (P < 0.01) in a dose dependent manner. In contrast, CSA caused only a slight decrease in albumin levels (P < 0.05). In addition, CSA slightly increased the amount of LDH in HepG2 cells and did not interfere with the IL-6-induced decrease in albumin synthesis.

CONCLUSIONS

These findings suggest that IL-6, but not IL- 10, may play an important role in the suppression of hepatic albumin secretion. FK506 but not CSA protects against the suppression of hepatic albumin synthesis caused by IL-6.