Endothelial activation, inflammation and premature atherosclerosis in children with familial dyslipidemia.

OBJECTIVES: Prospective studies demonstrated an increased cardiovascular risk in subjects with high levels of either the endothelial-platelet activation marker P-selectin or high-sensitivity C-reactive protein (hs-CRP). Both children with heterozygous familial hypercholesterolemia (FH) and those with familial combined hyperlipidemia (FCHL) are prone to premature atherosclerosis. Our objective was to investigate in children with either FH or FCHL whether P-selectin and hs-CRP contribute to carotid intima-media thickness (IMT), along with increased plasma lipid levels. METHODS: Carotid IMT, serum lipids and soluble P-selectin and hs-CRP levels were measured in 88 children (mean age 10.5+/-4.3 years) including 44 dyslipidemic children (25 with FH and 19 with FCHL) and 44 non-dyslipidemic controls. RESULTS: Carotid IMT was significantly higher among dyslipidemic than in control children (0.46+/-0.06mm vs 0.43+/-0.06mm, p=0.003) and serum P-selectin levels as well [129(50-254)ng/mL vs 50(24.5-130)ng/mL, p<0.001]. FH but not FCHL children had higher hs-CRP levels than controls [0.7(0.01-6.9)mg/L vs 0.3(0.1-1.2)mg/L, p=0.006]. In the entire sample of dyslipidemic children, carotid IMT was positively associated with soluble P-selectin levels (rho=0.30, p=0.049), but not with hs-CRP. The association between P-selectin and carotid IMT was independent from confounders, including plasma lipid levels. CONCLUSION: Endothelial-platelet activation, more than low-grade systemic inflammation, correlates with premature atherosclerosis among children with familial dyslipidemia, this association being independent from plasma lipid levels.

The type of LDLR gene mutation predicts cardiovascular risk in children with familial hypercholesterolemia.

OBJECTIVE: To ascertain whether the molecular characterization of a defect in the low-density lipoprotein (LDL) receptor gene (LDLR) in children with heterozygous familial hypercholesterolemia (heFH) identifies subjects at greater risk of developing premature coronary artery disease (pCAD) later in life. STUDY DESIGN: We investigated 264 children with heFH from 201 families, along with 148 affected parents and 100 unaffected siblings. The lipid profile was assessed before any treatment was provided, and genotype analysis was performed to characterize LDLR defects. In a subgroup of children with heFH and controls, we measured aorta and carotid intima-media thickness (aIMT and cIMT). The prevalence of pCAD in parents and/or grandparents with heFH was recorded. RESULTS: The children with heFH with a family history of pCAD had higher LDL cholesterol and apolipoprotein B levels and greater aIMT and cIMT than those with negative family history. Compared with carriers of LDLR-defective mutations, carriers of LDLR-negative mutations had a more severe phenotype, in terms of plasma lipid levels and IMT, and a higher prevalence of pCAD in first-degree relatives (36% vs 6.7%; P < .001). CONCLUSIONS: The study of heFH in children, in which other risk factors for CAD play a minor role, allows early identification of those at increased risk for developing pCAD, who merit more stringent clinical control and early pharmacologic treatment.