Open AccessLoss of Hepatic Carcinoembryonic Antigen‐Related Cell Adhesion Molecule 1 Links Nonalcoholic Steatohepatitis to Atherosclerosis
Author(s) -
Ghadieh Hilda E.,
Abu Helal Raghd,
Muturi Harrison T.,
Issa Daniella D.,
Russo Lucia,
Abdallah Simon L.,
Najjar John A.,
Benencia Fabian,
Vazquez Guillermo,
Li Wei,
Najjar Sonia M.
Publication year - 2020
Publication title -
hepatology communications
Language(s) - English
Resource type - Journals
ISSN - 2471-254X
DOI - 10.1002/hep4.1590
Subject(s) - medicine , endocrinology , insulin resistance , hyperinsulinemia , steatohepatitis , proinflammatory cytokine , fatty liver , insulin receptor , insulin , biology , inflammation , disease
Patients with nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) commonly develop atherosclerosis through a mechanism that is not well delineated. These diseases are associated with steatosis, inflammation, oxidative stress, and fibrosis. The role of insulin resistance in their pathogenesis remains controversial. Albumin ( Alb ) Cre + Cc1 flox ( fl ) /fl mice with the liver‐specific null deletion of the carcinoembryonic antigen‐related cell adhesion molecule 1 ( Ceacam1 ; alias Cc1 ) gene display hyperinsulinemia resulting from impaired insulin clearance followed by hepatic insulin resistance, elevated de novo lipogenesis, and ultimately visceral obesity and systemic insulin resistance. We therefore tested whether this mutation causes NAFLD/NASH and atherosclerosis. To this end, mice were propagated on a low‐density lipoprotein receptor ( Ldlr ) −/− background and at 4 months of age were fed a high‐cholesterol diet for 2 months. We then assessed the biochemical and histopathologic changes in liver and aortae. Ldlr −/− AlbCre + Cc1 fl/fl mice developed chronic hyperinsulinemia with proatherogenic hypercholesterolemia, a robust proinflammatory state associated with visceral obesity, elevated oxidative stress (reduced NO production), and an increase in plasma and tissue endothelin‐1 levels. In parallel, they developed NASH (steatohepatitis, apoptosis, and fibrosis) and atherosclerotic plaque lesions. Mechanistically, hyperinsulinemia caused down‐regulation of the insulin receptor followed by inactivation of the insulin receptor substrate 1–protein kinase B–endothelial NO synthase pathway in aortae, lowering the NO level. This also limited CEACAM1 phosphorylation and its sequestration of Shc‐transforming protein (Shc), activating the Shc–mitogen‐activated protein kinase–nuclear factor kappa B pathway and stimulating endothelin‐1 production. Thus, in the presence of proatherogenic dyslipidemia, hyperinsulinemia and hepatic insulin resistance driven by liver‐specific deletion of Ceacam1 caused metabolic and vascular alterations reminiscent of NASH and atherosclerosis. Conclusion: Altered CEACAM1‐dependent hepatic insulin clearance pathways constitute a molecular link between NASH and atherosclerosis.