The Progenitor Cell Compartment in the Feline Liver: An (Immuno)Histochemical Investigation

Abstract

Abstract. The hepatic progenitor compartment is of vital importance in liver regeneration when hepatocellular replication is impaired, as it occurs in acute fulminant hepatitis or severe liver fibrosis. It consists of resident progenitor cells in the normal liver, and ductular reaction and intermediate hepatobiliary cells in diseased livers. An histologic and immunohistochemical study was conducted to demonstrate putative hepatic progenitor cells in the normal liver (n 5 5) and in a range of hepatic diseases (n 5 13) in the cat. Formalin-fixed, paraffin-embedded specimens were stained with HE, the van Gieson stain, and the reticulin stain according to Gordon and Sweet, and immunohistochemically stained for cytokeratin-7 (CK7), human hepatocyte marker 1 (Hepar1), and multidrug resistancebinding protein-2/ATP binding cassette C2 (MRP2). The normal feline liver contains a liver progenitor cell morphologically similar to humans and dogs, which resides in the canal of Hering. In acute and chronic feline liver diseases a ductular reaction is present, whether in the parenchyma or in a portal or septal location. The putative progenitor cells could easily be demonstrated by staining for CK7, whereas they were generally negative for Hepar1 and MRP2. In a parenchymal ductular reaction mitotic figures and cells with an intermediate hepatobiliary phenotype could be demonstrated. This is the first account of hepatic progenitor cells in feline liver.

Presumed primary and secondary hepatic copper accumulation in cats

“…8 Hepatic copper concentrations in those cats were approximately 4,000 µg/g of dry weight. Information in 2 other anecdotal reports 11,20 of cats with suspected PCH has not helped characterize this syndrome. In 1 study 11 regarding hepatic copper accumulation in cats with spontaneously developing hepatobiliary disorders, only qualitative characteristics of copper distribution but not quantitative measures of copper concentrations were determined.…”

Hepatic copper and iron accumulation and histologic findings in 104 feline liver biopsies

“…5,14 Copper-associated hepatitis has also been reported in a 2-year-old male intact Abyssinian cat and a 0.5-year-old male intact Somali cat, though clinical findings and outcome were not reported. 9 Prognosis for dogs with primary copper-associated hepatopathies varies with stage of disease at diagnosis; dogs diagnosed while still asymptomatic have a much better outcome. It seems reasonable that stage of disease at diagnosis and severity of copper accumulation would similarly impact on prognosis for cats.…”

Histopathologic Features, Immunophenotyping, Clonality, and Eubacterial Fluorescence In Situ Hybridization in Cats With Lymphocytic Cholangitis/Cholangiohepatitis

“…18,31 This histologic feature has not been described in cats with lymphocytic cholangitis, and it may serve as a marker of bile duct immunoinjury as lymphocytes target or ''chase'' bile ductules.…”