alpha-Tocopherol supplementation reduces inflammation and apoptosis in high cholesterol mediated nonalcoholic steatohepatitis.


Demirel-Yalciner T., Sozen E. , Ozaltin E., Sahin A. , Ozer N.

BioFactors (Oxford, England), vol.47, pp.403-413, 2021 (Journal Indexed in SCI Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 47
  • Publication Date: 2021
  • Doi Number: 10.1002/biof.1700
  • Title of Journal : BioFactors (Oxford, England)
  • Page Numbers: pp.403-413
  • Keywords: apoptosis, fibrosis, high cholesterol diet, inflammation, NASH, alpha-tocopherol, FATTY LIVER-DISEASE, HEPATIC STELLATE CELLS, OXIDATIVE STRESS, VITAMIN-E, LIPID OXIDATION, C-JUN, EXPRESSION, AUTOPHAGY, NAFLD, ACIDS

Abstract

Inflammation and apoptosis signaling are crucial steps in the progression from nonalcoholic fatty liver disease (NAFLD) to nonalcoholic steatohepatitis (NASH). Alpha-tocopherol, the most active form of vitamin E, is an important modulator of signaling mechanisms, but its involvement to cholesterol-induced NASH pathogenesis remains poorly defined. Herein we have reported a novel effect of alpha-tocopherol in the transition from hepatic steatosis to NASH. High cholesterol diet alone (without alpha-tocopherol) in rabbits elevated NASH development as indicated by increased inflammatory response, apoptotic activity and liver fibrosis. Such elevation results from induction of signaling mechanisms since the expressions of IL1 beta, phospho c-Jun/c-Jun ratio, JNK, caspase 9, CHOP and Bax were increased, and recruitment of macrophage, alpha-smooth muscle actin (alpha-SMA) and COL1A1 into the liver tissue were induced. Alpha-tocopherol supplementation inhibited inflammatory response, apoptosis and fibrosis development without affecting lipid accumulation in high cholesterol-induced NASH. Specifically, alpha-tocopherol lowered the inflammatory level as observed by reduced macrophage infiltration and JNK/c-Jun signaling. Lower inflammatory status co-occurred with the reduction of CHOP and Bax expressions as well as fibrosis-related COL1A1 and alpha-SMA levels. Taken together, alpha-tocopherol supplementation inhibits cholesterol-induced NASH development by lowering JNK/c-Jun/inflammation axis in addition to JNK/CHOP/apoptosis signaling, which might contribute to resistance against NAFLD/NASH transition.