Cellular senescence in livers from children with end stage liver disease

Abstract

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

Figure 1. Representative images of senescence associated marker (β-galactosidase) and cell cycle markers (p16^INK4a, p21^cip1 and p53).

SA-βgal expression (turquoise blue) in fresh liver sections of the recipients with end stage liver disease. (A–B) Intense SA-βgal in canals of Hering (cH), interlobular bile ducts (bd) and cholangioles (ch) in a patient with biliary atresia. (case 2) Magnification: 20×, 60×. (C) Ductular transformation of hepatocytes (dt) exhibiting SA-βgal in a patient with fulminant hepatic failure (case 4). Magnification: 40×. (D–I) Nuclear staining in formalin fixed paraffin embedded livers with end stage liver disease. (D) p53 canals of Hering (cH) and interlobular bile ducts (bd) in a patient with biliary atresia (case 3). (E) Canals of Hering (cH), interlobular bile ducts (bd) and hepatocyte ductular transformation (dt) in a patient with acute liver failure (case 4). (F) Hepatocytes in the regenerative nodules (h) and in the bile duct in the fibrotic bands (bd) in a patient with tyrosinemia (case 1), Magnification: 40×. (G) p16^INK4a staining in the hepatocytes (h) inside a regenerative nodule (case 1). Magnification: 20×, (H) p21^cip1, staining in bile duct (bd) in the fibrotic bands and in the hepatocytes (h) inside a regenerative nodule (case 1). Magnification: 40×. (I) p21^cip1 staining in the nuclei of cells that aggregate to form ductular transformation structures (dt) (case 4). Magnification 40×.