Effect of Glycemic Control on Plasma Oxidized Low Density Lipoprotein Levels in Diabetics

Abstract

Objective: Increased low-density lipoprotein (LDL) glycation in diabetics could facilitate LDL oxidation, which is proatherogenic. I studied plasma oxidized LDL (OxLDL) levels in diabetics and non-diabetics, their relation to glycemic control, and their circadian variations. Methods: OxLDL in diabetics (n=32) and in non-diabetics without coronary artery diseases (n=20) were compared. OxLDL in diabetics (n=24) was measured on Days 2, 3, 4, 8 and the last day of hospitalization. Circadian variation in OxLDL in diabetics (n=18) was also examined. Glycemic control was implemented during hospitalization. Patients: The diabetics were divided into two groups; moderately-controlled (MC) group (HbA1c < 9.0% at admission, n = 15) and poorly-controlled (PC) group (HbA1c ≧ 9.0% at admission, n = 9). Results： In the MC group, OxLDL decreased by 20.8% after glycemic control (p = 0.0139), but not in the PC group. OxLDL is correlated with LDL on Days 3, 4, 8 (r = 0.837, 0.864, 0.801, respectively), TG on Day 8(r = 0.932), and Lp(a) at discharge (r = 0.871). In the PC group, OxLDL was 15.8% higher on the average in the daytime than at night (p = 0.0024). Conclusion： Plasma OxLDL is decreased by glycemic control, particularly in moderately glycemic controlled patients. OxLDL has a circadian variation, particularly in poorly glycemic controlled patients. Long-term glycemic control could reduce the progression of atherosclerosis, by reducing OxLDL levels.