Identification of mildly oxidized low-density lipoprotein (electronegative LDL) and its auto-antibodies IgG in children and adolescents hypercholesterolemic offsprings

Background Oxidative modification of low-density lipoproteins (LDL) is an essential step in atherogenesis, generating minimally oxidized LDL, also called electronegative LDL [LDL(−)], which has chemotactic, cytotoxic and immunogenic properties. Methods and results Serum LDL(−) and anti-LDL(−) auto-antibodies (IgG) were evaluated in 28 children and adolescents with familial hypercholesterolemia (FH) antecedents, with or without early coronary artery disease in first-degree relatives (eCAD), hypercholesterolemic (hc) or normocholesterolemic (nc) versus a control group of normocholesterolemic children without pathologic antecedents (C). ELISA method was used for detection of LDL(−) and anti-LDL(−) IgG. LDL(−) serum levels did not differ among the four groups (FH-eCAD-hc 41.4 ± 24.9 μg/dl; FH-hc 38.3 ± 11.2 μg/dl; FH-nc 47.3 ± 17.0 μg/dl and C 44.2 ± 28.8 μg/dl, p = 0.659). However, IgG anti-LDL(−) auto-antibodies were significantly higher in the control group in comparison to the FH groups with or without eCAD, independent of hypercholesterolemia or normocholesterolemia (FH-eCAD-hc 0.825 ± 0.289 μg/dl; FH-hc 0.667 ± 0.307 μg/dl; FH-nc 0.763 ± 0.204 μg/dl and C 1.105 ± 0.233 μg/dl, p = 0.006). When the auto-antibodies of groups with FH, with or without eCAD and with or without hypercholesterolemia were compared, no differences were found (p = 0.509). Conclusion These results showed that FH and/or eCAD children and adolescents have lower titers of auto-antibodies anti-LDL(−) than children from normal families, independent of serum LDL-cholesterol or serum LDL(−).