Positive association between plasma levels of oxidized low-density lipoprotein and myeloperoxidase after hemodialysis in patients with diabetic end-stage renal disease

Abstract

End-stage renal disease (ESRD) patients undergoing hemodialysis (HD) have a high prevalence of cardiovascular events. Low-density lipoprotein (LDL) in dialysis patients has been shown to be susceptible to in vitro peroxidation; therefore, oxidized-LDL (ox-LDL) could be generated in these patients. Moreover, myeloperoxidase (MPO) released from activated neutrophils may play a role in the induction of LDL oxidation. The purpose of this study was to investigate the relationship between plasma ox-LDL levels, plasma MPO levels, and serum high-sensitivity C-reactive protein (hs-CRP) levels during initial HD in patients with diabetic ESRD. Patients (n=28) had serial venous blood samples drawn before and after HD at the initial, second, and third sessions. Plasma ox-LDL levels were measured using a specific monoclonal antibody (DLH3), and plasma MPO levels were measured using an enzyme-linked immunosorbent assay kit. Plasma ox-LDL levels and MPO levels after a single HD session increased significantly (ox-LDL, P<0.005; MPO, P<0.0001) compared with levels before that HD session. However, the increase was transient since the levels returned to pre-HD session levels. Additionally, plasma MPO levels showed a positive correlation with plasma ox-LDL levels during HD (R=0.62, P=0.0029). No significant change was observed in serum hs-CRP levels before and after each HD session. This study demonstrates that plasma MPO levels are directly associated with plasma ox-LDL levels in diabetic ESRD patients during initial HD. These findings suggest a pivotal role for MPO and ox-LDL in the progression and acceleration of atherosclerosis in patients undergoing HD.

Keywords: atherosclerosis; end-stage renal disease; inflammation; oxidative stress.