Cellular Senescence in Livers from Children with End Stage Liver Disease

Background: Senescent cells occur in adults with cirrhotic livers independent of the etiology. Aim: Investigate the presence rate of cellular senescence and expression of cell cycle check points in livers from children with end stage disease. Methodology/Principal Findings: Livers of five children aged three years or less undergoing liver transplantation due to tyrosinemia (n = 1), biliary atresia (n = 2), or fulminant hepatitis (n = 2) were analyzed for senescence associated beta-galactosidase (SA-beta gal) activity and p16INK4a, p21cip1 and p53. All livers displayed positive cellular staining for SA-beta gal in the canals of Hering and interlobular biliary ducts. In the presence of cirrhosis (3/5 cases) SA-beta gal was found at the cholangioles and hepatocytes surrounding the regenerative nodules. Children with fulminant hepatic failure without cirrhosis had significant ductular transformation with intense SA-beta gal activity. No SA-beta gal activity was evident in the fibrous septa. Staining for p53 had a similar distribution to that observed for SA-beta gal. Staining for p16(INK4a) and p21(cip1) was positive in the explanted liver of the patient with tyrosinemia, in the hepatocytes, the canals of Hering, cholangioles and interlobular bile ducts. In the livers with fulminant hepatitis, p21(cip1) staining occurred in the areas of ductular transformation and in the interlobular bile ducts. Conclusions/Significance: Cellular senescence in livers of children with end stage disease is associated with damage rather than corresponding to an age dependent phenomenon. Further studies are needed to support the hypothesis that these senescence markers correlate with disease progression.