NASH-inducing diets in Göttingen Minipigs

Abstract Background Due to the human-like physiology, a minipig model of non-alcoholic steatohepatitis (NASH) could be valuable. Pigs, however, rarely develop substantial hepatic steatosis, even when fed diets with high fat, fructose and cholesterol (FFC) content. The potential of choline-deficient, amino acid defined high fat diets (CDAHFD) was therefore evaluated in Gottingen Minipigs. Methods Castrated male Gottingen Minipigs were fed either Chow (n=5) or one of three NASH diets: FFC (n=5); CDAHFD with sucrose (CDAHFD-S; n=4) or fructose (CDAHFD-F; n=4) for 8 weeks. Liver and blood samples were collected after 2 weeks and at termination. Results Compared to Chow, the body weight was higher after FFC (9.8 ± 0.4 versus 8.5 ± 1.2 kg; mean ± SD) and less after CDAHFD-S (6.4 ± 0.8 kg) and CDAHFD-F (6.9 ± 0.8 kg). Liver weight per kg body weight was significantly increased in all 3 NASH groups (FFC 2.1 times; and both CDAHFD diets 3.1 times). Histologically, pronounced macrovesicular steatosis developed only in the CDAHFD groups. Inflammation was present in all three NASH groups. In the CDAHFD groups, inflammatory cells formed crown-like structures around steatotic hepatocytes. Sirius red staining revealed mild fibrosis in the two CDAHFD groups with the fibrotic potential being further supported by immunohistochemical staining for activated stellate cells and gene expression analyses. No noticeable differences were found between CDAHFD-S and CDAHFD-F. Conclusions Gottingen Minipigs fed CDAHFD developed pronounced steatosis with inflammation around steatotic hepatocytes and incipient fibrosis, thereby showing potential as a model for human NASH. Further studies are needed to investigate the period needed for marked fibrosis to develop.