Apolipoprotein E phenotype regulates cholesterol absorption in healthy 13-month-old children - The STRIP study

High serum cholesterol concentration is one of the key risk factors in deve lopment of atherosclerosis, which may begin early in life and later progres s to symptomatic coronary heart disease. In adults, apoE polymorphism stron gly influences cholesterol metabolism, as subjects with apoE 3/4 or 4/4 (co llectively called apoE4) phenotype absorb cholesterol effectively and thus also have higher cholesterol absorption-reflecting plant sterol concentrati ons in serum than subjects with other apoE phenotypes. Because of the inver se correlation of absorption and synthesis of cholesterol, concentrations o f cholesterol synthesis-reflecting serum cholesterol precursor sterols are lower in subjects with apoE4 than in subjects with other phenotypes. To ana lyze whether apoE phenotype affects cholesterol absorption and synthesis in early childhood, we measured serum plant sterol (campesterol and sitostero l) and cholesterol precursor sterol (desmosterol and lathosterol) concentra tions in healthy 13-month old children using gas-liquid chromatography. The 36 study children were participants in a randomized prospective trial (the Special Turku Coronary Risk Factor Intervention Project) aimed at decreasi ng exposure of the children to environmental atherosclerosis risk factors. The 16 apoE4 children had 30% to 50% higher cholesterol-adjusted campestero l and sitosterol concentrations in serum than the 20 apoE 3/3 children (p = 0.002 and p = 0.02, respectively). The concentrations of cholesterol precu rsor sterols in serum did not differ between the two groups of children. We conclude that the young apoE4 children may absorb cholesterol and plant st erols more effectively than the children with apoE 3/3 phenotype without co mpensatory reduction in endogenous synthesis of cholesterol.