Ketone body production is differentially altered in steatosis and non-alcoholic steatohepatitis in obese humans.

ABSTRACT

BACKGROUND & AIMS: Levels of ketone bodies have been reported to be both increased and decreased in individuals with non-alcoholic fatty liver disease. We investigated whether the metabolism of ketone bodies is different in simple steatosis and in non-alcoholic steatohepatitis (NASH). METHODS: Serum low molecular weight molecules including ketone bodies were measured using high-throughput proton (1H) nuclear magnetic resonance in 116 (76 categorized unequivocally to those with normal liver, simple steatosis or NASH) morbidly obese individuals [age 47.3 ± 8.7 (mean ± SD) years, body mass index 45.1 ± 6.1 kg/m(2) , 39 men and 77 women] with histological assessment of NASH and analysis of gene expression in the liver. Finally, we correlated ß-hydroxybutyrate (ß-OHB) levels with NASH predicting score in Metabolic Syndrome in Men Study (METSIM) population study (n = 8749 non-diabetic men). RESULTS: Levels of ketone bodies were lower in individuals with NASH compared to individuals with simple steatosis (P = 0.004 and P = 0.018 for ß-OHB and acetoacetate respectively). Lower levels of ß-OHB were associated with the NASH predicting score in the METSIM study (P = 0.001). Liver inflammation correlated with mRNA expression of genes regulating ketolysis in the liver (Spearman correlation 0.379-0.388, P < 0.0006 for ACAT1, ACSS2 and BDH1). CONCLUSION: Lower levels of ketone bodies in individuals with NASH compared to individuals with simple steatosis suggest a decrease in ketone body metabolism in NASH.