Effect of histone deacetylase inhibitor (vorinostat) on new-onset diabetes induced by tacrolimus.

Objective: The immunosuppressant tacrolimus is a major cause of new-onset diabetes after transplantation. The aim of this study was to evaluate whether a low dose of the histone-deacetylase inhibitor (vorinostat) might ameliorate tacrolimus-induced new-onset diabetes.

Methods: Thirty 8-week-old male Wistar rats were randomly divided into five groups: a control group, tacrolimus group (1.5 mg/kg intraperitoneally for 28 days), vorinostat group (15 mg/kg orally for 28 days), a group receiving tacrolimus with vorinostat for 28 days; and a group receiving coadministration of tacrolimus for 28 days and vorinostat for 14 days. Diabetes development was assessed on the basis of serum glucose, insulin, HOMA-IR and C-peptide. To investigate the mechanism of vorinostat, we assessed inflammatory markers (tumor necrosis factor-α and interleukin-1β), an antioxidant marker (glutathione), an oxidant marker (nicotinamide adenine dinucleotide phosphate hydrogen oxidase) and an apoptosis marker (caspase-3). Kidney functions (creatinine and blood urea nitrogen) were also assessed.

Results: The administration of tacrolimus for 28 days resulted in significantly increased serum glucose and decreased C-peptide and insulin levels than those in the control group. However, coadministration of vorinostat significantly decreased hyperglycemia and increased C-peptide and insulin levels. Moreover, combined treatment with tacrolimus and vorinostat, compared with tacrolimus treatment alone, resulted in significantly reduced inflammatory and oxidant markers, and increased glutathione. Additionally, vorinostat improved the kidney parameters.

Conclusion: Vorinostat at a low dose (15 mg/kg) induces anti-inflammatory and antioxidative effects that protect the pancreas and kidney against the development of new-onset diabetes due to tacrolimus in rats. This experimental study provides insights supporting further clinical trials to improve the post-kidney transplantation protocol through addition of vorinostat to the immunosuppressive regimen.