Oxidized LDL at low concentrations inhibits in vitro angiogenesis of human coronary artery endothelial cells. Hermes Toros Xavier, Dulcinéia Saes Parra Abdalla, Tânia Leme da Rocha Martinez, Antonio Ricardo de Toledo Gagliardi, José Antonio Franchini Ramires

Abstract

 To investigate the effects of low concentrations of oxidized LDL (oxLDL) on in vitro cell angiogenesis, represented by tube formation from human coronary artery endothelial cells (HCAEC). Methods and Results: Cultures of HCAEC were treated with low concentrations of native LDL (nLDL) isolated from human plasma, electronegative LDL [LDL(-)], a sub-fraction of LDL with minimal oxidative characteristics, and chemical minimally oxidized LDL, through methods of low degree and times of oxidation; the effects were compared. We established the ability of nLDL, LDL(-), oxLDL(ENO-HCO3-/1’) and oxLDL(ENO-HCO3-/10’) in low concentrations, of 1 and 4 µg/mL, to investigate their effects on tube formation from HCAECs in Matrigel™. No inhibiting effect nLDL was observed on tube formation from HCAECs. LDL(-), oxLDL(ENO-HCO3-/1’) or oxLDL(ENO-HCO3-/10’) inhibited the formation of capillary-like structures in a dose-dependent manner. Conclusion: The effects of oxLDL on the coronary endothelial cells in culture, inhibiting the process of angiogenesis are proportional to the concentration and degree of oxidation of LDL. Our data, however, should be interpreted in light of the limitations inherent in in vitro experimentation, albeit their value in exploring pathophysiological mechanisms. Yet, these resuts furnish new insight into mechanisms by which OxLDL may impair endothelial functions related to atherogenesis and its clinical complications.