Liver regeneration is impaired by FK778 in partially hepatectomized rats, while supplemental uridine restores both liver growth and hepatocyte proliferation

Aim: The impact of mandatory immunosuppression on liver regeneration after segmental liver transplantation is of clinical importance. FK778, a novel immunosuppressant, inhibits pyrimidine biosynthesis and prevents rejection after organ transplantation in a dose-dependent manner. We investigated the effect of FK778 at a highly effective dose on liver regeneration in a small animal model. Methods: Inbred Lewis rats were subjected to 70% partial hepatectomy (PH) and treated with saline (n = 28), uridine (n = 16), FK778 alone (n = 28) or in combination with uridine (n = 16). FK778 was given intravenously daily at a dose of 25 mg/kg bodyweight (bw) and uridine was given daily intraperitoneally at a dose of 250 mg/kg bw. Liver bodyweight ratio (LBR), hepatocyte proliferation index (PI), blood chemistry and morphological analysis were incorporated. PI was determined by Ki-67 immunostaining. De Ritis ratio was calculated to assess the extent of liver damage. Results: In FK778-treated animals PI was decreased at 24 h and 72 h and LBR was lower at 48 h and 72 h (P