Abstract

Background: Alcoholic associated liver disease (AALD) is a poorly characterized pathology characterized by steatosis, inflammation and fibrosis. The lack of an animal model which recapitulates key features of AALD has been a major limitation in understanding its etiology and in the development of effective therapies. To identify the cellular differences between the mouse and human liver responsible for the different injury response to alcohol we have generated humanized mice that can support human liver cells (parenchymal and non-parenchymal cells) along with human hematopoiesis [1].

Methods: In humanized and non-humanized mice (control mice having mouse liver and mouse hematopoiesis), we applied the NIAAA model of chronic and binge ethanol feeding (10-days ad libitum oral feeding with the Lieber-DeCarli ethanol liquid diet plus a single binge ethanol feeding 9 hours before the end of the experiment). This model was evaluated by: i) Serum ALT and bilirubin, ii) flow cytometry to define the immune cell composition in the liver and blood iii) H&E staining to assess steatosis, inflammation and ballooning iv) human/mouse aSMA and human Collagen-3 to asses mouse and human hepatic stellate cells activation and v) human CK8/18 to asses Mallory bodies formation.

Results: We have seen that humanized mice had higher degree of steatosis, inflammation and ALT levels than non-humanized. In particular, the humanized mice had severe macrovesicular steatosis with Mallory bodies and ballooning whereas non humanized mice have minimal microvesicular steatosis. Also, humanized mice only have abnormal levels of bilirubin, mild to moderate fibrosis, severe peripheral lymphopenia. Of note, in the high degree steatotic areas of humanized mice, we observed human hepatic stellate cell activation between steatotic human hepatocytes, and human collagen.

Conclusion: We have demonstrated that by fully humanizing mouse livers key features of AALD can be reproduced to a greater degree than they can in mouse only livers. This will be the first mouse alcohol model having high degree of macrovesicular steatosis in human hepatocytes, alcohol-driven fibrosis mediated by human hepatic stellate cells, and pathological immune responses driven by human Immune cells. This model will be a unique tool to study pathways leading to severe steatotic, fibrotic and inflammatory responses of ALD.

References

1. Song, Y., et al., Combined liver-cytokine humanization comes to the rescue of circulating human red blood cells.Science, 2021. 371(6533): p. 1019-1025.