Relation between liver fat content and the rate of VLDL apolipoprotein B-100 synthesis in children with protein-energy malnutrition

Abstract

Background: Fatty infiltration of the liver is associated with an increased morbidity and mortality in children with severe protein-energy malnutrition (PEM), but its pathogenesis remains unclear. Although impaired synthesis of VLDL apolipoprotein B-100 (VLDL-apo B-100) is generally accepted as the pathogenetic mechanism, the rate of it synthesis has not been measured in children with PEM.

Objective: The objective of the study was to ascertain the relation between the degree of hepatic steatosis and the rate of VLDL-apo B-100 synthesis in children with PEM.

Design: The fractional and absolute rates of VLDL-apo B-100 synthesis were measured with a prime-constant intravenous infusion of [2H3]leucine in 13 severely malnourished children (8 boys and 5 girls) aged 7-18 mo. Hepatic fat content was estimated by computerized tomography scanning by using the ratio of liver to spleen (L:S) attenuation. The ratio is inversely related to hepatic fat content such that the lower the L:S, the greater the amount of fat in the liver.

Results: There were significant inverse relations between L:S attenuation and VLDL-apo B-100 concentration (P < 0.02), the absolute rate of VLDL-apo B-100 synthesis (P < 0.02), and plasma triacylglycerol (P < 0.02) and serum cholesterol (P < 0.05) concentrations.

Conclusions: These results suggest that children with PEM synthesize VLDL-apo B-100 at a faster rate as the degree of hepatic fat infiltration increases. Thus, fatty infiltration of the liver in PEM is not due to a reduction in the synthesis of VLDL-apo B-100.