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 (Q. 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 mu g/dl; FH-hc 38.3 +/- 11.2 mu g/dl; FH-nc 47.3 +/- 17.0 mu g/dl and C 44.2 28.8 l.Lg/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 mu g/dl; FH-hc 0.667 +/- 0.307 mu g/dl; FH-nc 0.763 +/- 0.204 mu g/dl and C 1.105 +/- 0.233 mu g/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(-). (c) 2005 Elsevier Ireland Ltd. All rights reserved.