Dyslipoproteinemia and oxidative modification of low-density lipoprotein (oxLDL) contribute to the development of oxidative stress and atherosclerosis in chronic kidney disease (CKD). On the contrary, high-density lipoprotein cholesterol (HDL-C), especially HDL3-C subtype, has protective effect against oxidative damage. There is limited evidence referring HDL-C subclass levels in patients on dialysis. This study was designed to compare lipid abnormalities and oxLDL levels in hemodialysis (HD) and peritoneal dialysis (PD) patients. Serum lipids, HDL subclasses, and oxLDL were measured in 55 patients with CKD-stage 5 (31 patients on HD and 24 patients on PD) and in 21 normal controls (NC). The results showed that in dialysis patients, triglycerides were higher than in controls (p < 0.0001) and HDL-C was significantly lower (p < 0.0001). The HDL2-C subclass concentration did not differ significantly between patients and controls, while HDL3-C was lower in patients (11 ± 0.5 mg/dL) than in NC (23 ± 1, p < 0.0001). oxLDL levels were markedly increased in patients (1.92 ± 0.29 mg/L) compared to NC (0.22 ± 0.05, p < 0.0001). Patients on PD had higher levels of cholesterol (p < 0.001) and apolipoprotein B (p < 0.05) than patients on HD. However, HDL-C, HDL-C subclasses, and oxLDL concentrations did not differ significantly between PD and HD patients. It is concluded that patients with CKD have a nearly 10-fold elevation of oxLDL compared with NC. Patients on PD have differences in the lipid profile compared with patients on HD; however, both modalities seem to possess similar potential to atherosclerosis development.

Background:Dyslipoproteinemia and oxidative modification of LDL (oxLDL) are common symptoms in patients suffering from chronic renal failure on hemodialysis (HD), and contribute to the development of oxidative stress. High-density lipoprotein cholesterol (HDL-C) protects against atherosclerosis by inhibiting the oxidation of lipoproteins and by supporting reverse cholesterol transport. This study intends to examine the association of oxLDL with HDL2 and HDL3 subclasses of HDL-C in HD patients, in order to elucidate whether oxidative stress influences HDL-C composition. Methods: Thirty-four patients on HD and 21 age- and sex-matched controls were studied. HDL2 and HDL3-C subclasses were isolated from serum according to a single-step precipitation method following a homogenous HDL-C assay. oxLDL was measured by ELISA. Results: In HD patients, oxLDL concentration was higher compared to the controls (1.40 ± 0.47 vs. 0.21 ± 0.05 mg/l, p = 0.017) and was significantly associated to total cholesterol (r = 0.480, p = 0.044), LDL-C (r = 0.544, p = 0.019), HDL-C (r = –0.589, p = 0.027) and C-reactive protein (r = 0.578, p = 0.024). Comparing HDL-C subclasses, only HDL2-C was negatively correlated to oxLDL levels (r = –0.565, p = 0.035). Conclusions: In HD patients, high serum levels of oxLDL are associated with low HDL2-C subclass levels. This might suggest that oxidative stress affects the HDL subclass more related to the protecting activity of HDL-C, contributing to atherosclerosis development.

Oxidative stress plays a significant role in the development of inflammation in patients undergoing hemodialysis (HD). This study intends to evaluate the relationship between C-reactive protein (CRP) and the newly established marker of lipid peroxidation, d-ROMs (reactive oxygen metabolites), in comparison with different indicators of oxidative stress. Plasma total antioxidant capacity (TAC), lipid peroxidation products malonaldehyde (MDA) and 4-hydroxyalkenals, as well as d-ROMs, were determined in 24 patients before HD and in 21 normal controls (NC). It was found that HD patients had higher levels of d-ROMs than NC (p = 0.033). A highly significant positive correlation was observed between logCRP and d-ROMs concentrations (p < 0.0001, r = 0.85) in patients, but not in NC. The concentrations of TAC and MDA were not associated with CRP in HD or in NC individuals. It is concluded that d-ROMs concentration is a potent marker of oxidative injury that is strongly indicative of the inflammatory status in HD patients.

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