Background-Prospective epidemiological studies have shown that low plasma levels of HDL cholesterol (HDL-C) are associated with an increased risk for cardiovascular disease (CVD). Despite nearly 40 years of research, however, it is unclear whether this also holds true for individuals with severely reduced levels of HDL-C due to mutations in the lecithin:cholesterol acyltransferase (LCAT) gene. Better insight into CVD risk in these individuals may provide clues toward the potential of LCAT as a pharmaceutical target to raise HDL-C levels. Methods and Results-Lipids, lipoproteins, high-sensitivity C-reactive protein (CRP), and carotid artery intima-media thickness (IMT) were assessed in 47 heterozygotes for LCAT gene mutations and 58 family controls. Compared with controls, heterozygotes presented with a mean 36% decrease in HDL-C levels (PϽ0.0001), a 23% increase in triglyceride levels (PϽ0.0001), and a 2.1-fold increase in CRP levels (PϽ0.0001). Mean carotid IMT was significantly increased in heterozygotes compared with family controls (0.623Ϯ0.13 versus 0.591Ϯ0.08 mm). After adjustment for age, gender, and alcohol use, this difference proved statistically significant (PϽ0.0015). Conclusions-The data show that heterozygosity for LCAT gene defects is associated with low HDL-C levels and elevated concentration of triglycerides and CRP in plasma. This phenotype underlies increased IMT in carriers versus controls, which suggests that LCAT protects against atherosclerosis. This in turn indicates that targeting LCAT to raise HDL-C may reduce CVD risk.

In adults with familial hypercholesterolaemia (FH), cholesterol lowering with statins has been shown to improve the endothelial function, a hallmark of early atherogenesis. Currently, therapeutic options for treating high cholesterol levels in FH children are limited. Plant sterols safely and effectively reduce serum cholesterol concentrations by inhibiting cholesterol absorption. Therefore, we evaluated the effect of plant sterols on cholesterol and vascular function in prepubertal children with FH. We included 41 children (5-12 years old) with FH in a double-blind crossover trial using spreads containing 2.3 g of plant sterols (mainly sitosterol and campesterol) per 15 g spread and a placebo spread for a 4-week period, separated by a 6-week washout period. Lipid levels and endothelial function were assessed after both 4-week treatment periods. Endothelial function was assessed as flow-mediated dilation (FMD) of the brachial artery using a wall tracking system. Data were compared to those of 20 healthy controls. Intake of 2.3 g plant sterols per day decreased total cholesterol (-11%) and low-density cholesterol (-14%) as compared to placebo spread in FH children. FH children treated with placebo spread were characterized by an impaired FMD compared to healthy control children (7.2% +/- 3.4% versus 10.1% +/- 4.2%, p < 0.005). However, the reduction of LDL in FH children did not improve FMD (placebo: 7.2% +/- 3.4% versus plant sterols: 7.7% +/- 4.1%). In conclusion, the present study shows a clear reduction of LDL cholesterol by plant sterol treatment. However, short-term plant sterol treatment does not improve the endothelial function in FH children.