Is Plasma Alpha-Tocopherol Associated with Electronegative LDL in Obese Adolescents?

Abstract

Summary Obesity has increased in children and adolescents. What is reflected in the early occurrence of cardiometabolic alterations, like hypertension and type 2 diabetes, where the oxLDL formation is stimulated. Various studies have shown that plasma a-tocopherol (a-TP) can protect LDL against oxidation. Nevertheless, the action of plasma a-TP in cardiovascular diseases remains controversial. We conducted a cross-sectional study to evaluate plasma a-TP and its impact on the concentration of LDL(2). Adolescents (n5150) of both sexes were classified into three groups: healthy weight (HW; 50%), overweight (OV; 22%), and obese (OB; 28%). Lipid profile, LDL(2), anti-oxLDL and anti-LDL(2) antibodies, CRP (ELISA) and plasma a-TP (HPLC) were analyzed. Demographic, anthropometric, and food intake data were evaluated. Crude and energy-adjusted intake of vitamin E in the OB group were higher than in the HW group (p,0.001). Crude and energy-adjusted vitamin E intakes were not correlated with plasma a-TP (r520.07; p50. 412 and r520.064; p50.467, respectively). Subjects in the OB group had higher TC and LDL-C and lower HDL-C than in the HW and OV groups. C-reactive protein and anti-oxLDL antibodies changed as a function of BMI. The impact of obesity was reinforced by high values for LDL(2) and low content of plasma a-TP in comparison with the HW (p,0.001) and OV groups (p50.03). This negative profile was maintained for the ratio between a-TP and TC or LDL-C. Plasma a-TP, a-TP/TC and a-TP/LDL-C were negatively associated with LDL(2) and other cardiometabolic risk factors (BMI, WC, AC and anti-oxLDL). Our results demonstrate that obesity in adolescents is associated with high levels of LDL(2) and low plasma a-TP content.

Gender disparity in LDL-induced cardiovascular damage and the protective role of estrogens against electronegative LDL

“…Increased proportions of electronegative LDL have been described in many conditions that define metabolic syndrome, such as hypertriglyceridemia [10], diabetes [4,11], insulin resistance [12], obesity [13], and hypertension [14]. Previously, we separated plasma LDL according to charge into 5 subfractions, L1-L5, by using anion-exchange chromatography and showed that plasma levels of L5—the most electronegative subfraction of LDL—are higher in patients with MetS and ST-segment elevation myocardial infarction (STEMI) than in healthy individuals [15].…”

Association of oxidative stress biomarkers with adiposity and clinical staging in women with breast cancer

“…In addition, we have shown that LDL( − ) and α-tocopherol and retinol are inversely correlated. To date, these associations have not been reported in the literature although a relationship between LDL( − ) and α-tocopherol was previously observed in obese adolescents, 34 patients submitted to haemodialysis 35 and subjects with dyslipidaemia. 36 Delimares et al 37 observed that the oxLDL generation was associated with an increased risk of breast cancer (odds ratio = 1.02, 95% confidence interval = 1.001-1.031), suggesting that elevated oxLDL levels, indicating the involvement of lipid peroxidation, can lead to higher oxidative stress.…”

“…The LDL particles can be modified, resulting in a more electronegative LDL subfraction with oxidised characteristics 39 and proinflammatory properties. 40 Previously, we proposed that LDL( − ) is a potential early biomarker for oxidative stress; 34 this likelihood could be reinforced by their antibodies anti-LDL( − ). The present study confirms that women with breast cancer are in oxidative stress and show modified particles with different levels of oxidative damage.…”

Inter-relações entre índice -3, estresse oxidativo e composição corporal em mulheres com câncer de mama

“…In addition, we have shown that LDL(-) and -tocopherol and retinol are inversely correlated. To date, these associations have not been reported in the literature although a relationship between LDL(-) and -tocopherol was previously observed in obese adolescents (30), submitted to hemodialysis (31) and dyslipidemia (32).…”