RESUMO
OBJECTIVES: Vascular abnormalities such as endothelial dysfunction and arterial stiffness have been described in patients with beta-thalassemia major (beta-TM). Increased concentrations of oxidised low-density lipoprotein cholesterol (oxLDL) have been observed in those patients, but possible associations between oxLDL and arterial function in beta-TM have not been defined. METHODS: Twenty-six patients (11 males) with beta-TM (age 23 +/- 4 yr) and 30 age and gender-matched healthy subjects were studied. Aortic stiffness was assessed by carotid-femoral pulse wave velocity (PWVc-f) using applanation tonometry; brachio-radial artery stiffness was assessed by carotid-radial PWV (PWVc-r). Flow-mediated dilatation (FMD) of the brachial artery and oxLDL (ELISA) were also measured. RESULTS: Patients with beta-TM had higher oxLDL levels (68.6 +/- 13.7 mU/mg vs. 50.0 +/- 12.6 mU/mg, P = 0.005), decreased FMD (3.6 +/- 2.5% vs. 7.3 +/- 3.5%, P = 0.001) and higher PWVc-f compared with controls (8.4 +/- 1.7 vs. 7.2 +/- 1.1. P < 0.002). FMD of the brachial artery was negatively associated with OxLDL concentrations in simple linear (r(2) = -0.25, P = 0.001) and multiple linear regression analysis (beta = -0.242, P = 0.03, R(2) = 0.43, P = 0.0002). PWVc-r was positively associated with OxLDL (r(2) = 0.23, P = 0.003) and showed a tendency in multiple regression analysis (beta = 0.18, P = 0.05). PWVc-r and FMD were also significantly correlated (beta = -0.213, P = 0.04) in beta-TM patients. There was no association between oxLDL and PWVc-f. CONCLUSION: An association between oxLDL, arterial elastic properties and endothelial dysfunction of muscular arteries was found. OxLDL may represent a contributing factor for the vascular manifestations described in beta-TM patients.
