Hepatic stellate cell hypertrophy is associated with metabolic liver fibrosis

Céline Hoffmann,Julien Fernandes,Pascal Roux,Frédéric Charlotte,Anne Danckaert,Virginie Escriou,Isabelle Brocheriou,Karine Clément,Anne-Marie Lachagès,Fabienne Foufelle,Christine Charrueau,Dominique Bonnefont-Rousselot,Nour El Houda Djerir,Bernard Hainque,Vlad Ratziu,Pascal Bigey,Judith Aron-Wisnewsky

doi:10.1038/s41598-020-60615-0

Abstract

Hepatic fibrosis is a major consequence of chronic liver disease such as non-alcoholic steatohepatitis which is undergoing a dramatic evolution given the obesity progression worldwide, and has no treatment to date. Hepatic stellate cells (HSCs) play a key role in the fibrosis process, because in chronic liver damage, they transdifferentiate from a “quiescent” to an “activated” phenotype responsible for most the collagen deposition in liver tissue. Here, using a diet-induced liver fibrosis murine model (choline-deficient amino acid-defined, high fat diet), we characterized a specific population of HSCs organized as clusters presenting simultaneously hypertrophy of retinoid droplets, quiescent and activated HSC markers. We showed that hypertrophied HSCs co-localized with fibrosis areas in space and time. Importantly, we reported the existence of this phenotype and its association with collagen deposition in three other mouse fibrosis models, including CCl4-induced fibrosis model. Moreover, we have also shown its relevance in human liver fibrosis associated with different etiologies (obesity, non-alcoholic steatohepatitis, viral hepatitis C and alcoholism). In particular, we have demonstrated a significant positive correlation between the stage of liver fibrosis and HSC hypertrophy in a cohort of obese patients with hepatic fibrosis. These results lead us to conclude that hypertrophied HSCs are closely associated with hepatic fibrosis in a metabolic disease context and may represent a new marker of metabolic liver disease progression.

Highlights

HSCs are localized in the space of Disse, interposed between liver sinusoidal endothelial cells (LSECs) and hepatocytes; they represent ~10% of all resident liver cells
While using choline-deficient amino acid-defined and high fat diet (CDAHFD) mouse model in a parallel study to investigate the role of HSCs in the onset and development of hepatic fibrosis in a steatohepatitis context, we found out the existence of clusters of HSCs, characterized by a particular phenotype not previously described in a context of metabolic liver fibrosis
A slight perisinusoidal fibrosis was detected from the 6th week of CDAHFD administration, which started from the centrilobular zone and evolved progressively to a marked stage from 9 weeks and stabilized throughout the 22 weeks of experiment (Fig. 1e)

Summary

Introduction

HSCs are localized in the space of Disse, interposed between liver sinusoidal endothelial cells (LSECs) and hepatocytes; they represent ~10% of all resident liver cells. One of the most widely used liver toxins for experimental induction of a liver injury is carbon tetrachloride (CCl4)[9] This kind of hepatotoxic model reproduces some important features of human liver fibrosis, the etiology of the fibrosis is different from that resulting from a chronic metabolic liver disease such as NASH. Methionine and choline deficient (MCD) diet is the major nutritional model for NASH study and induces macrovesicular steatosis, hepatocellular death, inflammation, oxidative stress, and liver fibrosis[10]. This paper describes the characterization of this specific population of HSCs and focuses on demonstrating its association with hepatic fibrosis, on several animal models of metabolic liver fibrosis, as well as in a preliminary study on human samples exhibiting liver fibrosis

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Results

Conclusion