UC Irvine

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.

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 β-galactosidase (SA-βgal) activity and p16INK4a, p21cip1 and p53. All livers displayed positive cellular staining for SA-βgal in the canals of Hering and interlobular biliary ducts. In the presence of cirrhosis (3/5 cases) SA-βgal 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-βgal activity. No SA-βgal activity was evident in the fibrous septa. Staining for p53 had a similar distribution to that observed for SA-βgal. 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.

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.