Oxidative stress is associated with arterial dysfunction and enhanced intima-media thickness in children with hypercholesterolemia: the potential role of nicotinamide-adenine dinucleotide phosphate oxidase.
BACKGROUND
Endothelial dysfunction and intima-media thickness are precocious manifestations of hypercholesterolemia, but the mechanism is unclear.


OBJECTIVE
The aim of the study was to analyze the interplay among endothelial dysfunction, intima-media thickness, and oxidative stress in children with hypercholesterolemia.


METHODS
We performed a cross-sectional study comparing flow-mediated dilation, intima-media thickness, lipid profile, urinary isoprostanes as markers of oxidative stress, and platelet expression of gp91(phox), the catalytic unit of nicotinamide-adenine dinucleotide phosphate oxidase, in a population of 50 children with hypercholesterolemia (mean age +/- SD: 10.0 +/- 3.7 years) and 50 children without hypercholesterolemia (mean age: 9.2 +/- 3.5 years). Four children with hereditary deficiency of gp91(phox) were studied also.


RESULTS
Children with hypercholesterolemia had reduced flow-mediated dilation (mean +/- SD: 6.2 +/- 2.4 vs 9.2 +/- 2.5%) and enhanced intima-media thickness (0.45 +/- 0.07 vs 0.40 +/- 0.06 mm), urinary isoprostanes (86.9 +/- 51.6 vs 45.9 +/- 25.6 pg/mg creatinine), and gp91(phox) platelet expression (4.4 +/- 3.8 vs 2.0 +/- 1.7 mean fluorescence) compared with control subjects. At bivariate analysis, flow-mediated dilation was correlated with low-density lipoprotein cholesterol, intima-media thickness, urinary isoprostanes, and platelet gp91(phox). Stepwise multiple linear regression analysis showed that, in children with hypercholesterolemia, flow-mediated dilation and intima-media thickness were significantly associated with low-density lipoprotein cholesterol and urinary isoprostanes; also, gp91(phox) platelet expression was an independent predictor of urinary isoprostanes. Children with gp91(phox) hereditary deficiency showed downregulation of platelet gp91(phox) and reduced urinary excretion of isoprostanes.


CONCLUSIONS
The study suggests that gp91(phox)-mediated oxidative stress may have a pathogenic role in the anatomic and functional changes of the arterial wall occurring in children with premature atherosclerosis.
Martino
Francesco
F
IV Divisione di Clinica Medica, Viale del Policlinico 155, Rome, 00161, Italy.
Loffredo
Lorenzo
L
Carnevale
Roberto
R
Sanguigni
Valerio
V
Martino
Eliana
E
Catasca
Elisa
E
Zanoni
Cristina
C
Pignatelli
Pasquale
P
Violi
Francesco
F