Histological and immunohistochemical characterization of feline hepatic lipidosis.

Abstract

Feline hepatic lipidosis is an acute critical syndrome that can result into mortality. Classically this condition is considered to involve merely simple steatosis and not progress into liver failure. During histological evaluation some features of steatitis appear to be present. In human medicine there is a condition called non alcoholic fatty liver disease(NAFLD) involving steatosis, steatitis and cirrhosis, to which feline lipidosis may exhibit similarities. To further investigate feline lipidosis we performed immunohistochemistry on samples that have been histologically graded by the NAS-score, used for evaluation and staging of NAFLD.

Fifteen archival samples of cat liver have been included in this study, of which twelve feline lipidosis samples and three healthy control animals. All feline lipidosis samples have been scored for steatosis, ballooning, inflammation, fibrosis and oval cells resulting in a NAS-score. Samples have been evaluated by immunohistochemical staining for regeneration of hepatocytes or liver progenitor cells(LPC) (Ki67, K19), inflammatory reaction with macrophages and lymphocytes (MAC387, CD3), hepatic stellate cells(HSC) and fibrosis (αSMA, Sirius red). Feline lipidosis samples show little to no hepatocyte regeneration, little LPC activation and decreased numbers of macrophages and lymphocytes. In all feline lipidosis samples HSC are increased and early fibrosis is present.