HEPATIC SOD1 GENE EXPRESSION CHANGES IN THE NAFLD PATHOGENESIS IN OBESITY

Steatosis in the liver in obesity increases the work of mitochondria to utilize excess lipids. An overload of β-oxidation of fatty acids, the tricarboxylic acid cycle, and oxidative phosphorylation leads to a decrease in ATP and an increase in the formation of reactive oxygen species. Normally, mitochondria can efficiently remove elevated levels of reactive oxygen species using the cell's antioxidant system and metabolic adaptation to altered conditions. This study aimed to investigate the role of hepatic SOD expression in the pathogenesis of NAFLD in obesity. It was found that the level of SOD1 expression in the liver in obese patients with and without type 2 diabetes with a BMI > 40 kg/m2 was lower than in healthy donors. The copy number of mitochondrial DNA (mtDNA) in the liver in all obese patients was more than two times lower than in the control group. In the liver of obese patients without type 2 diabetes, the SOD1 protein level and the mtDNA copy number were interrelated and negatively correlated with the area of fatty inclusions. Thus, in obese patients, a decrease in antioxidant defense in the liver leads to the vulnerability of mitochondria, which, in turn, contributes to the progression of steatosis and insulin resistance.

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