Objective: Accumulation of advanced oxidation protein products (AOPP) has been found in patients with chronic kidney disease (CKD). The study was performed to investigate the association between serum levels of AOPP and atherosclerosis in CKD.
Methods: 109 CKD patients were involved in this cross-sectional cohort study. Carotid artery intima-medial thickness (IMT), cross-sectional calculated intima-media area (cIM area) and plaques were determined with non-invasive high-resolution B-mode ultrasonography. Serum levels of AOPP, malonyldialdehyde (MDA), glutathione peroxidase (GSHPx) and C-reactive protein (CRP) were also determined.
Results: Higher serum AOPP levels were found in patients with CKD [(64.72 +/- 19.69) micromol/L] as compared with those in healthy controls [(30.16 +/- 6.46) micromol/L, P < 0.01]. AOPP levels in dialysis patients [(70.02 +/- 16.51) micromol/L] were significantly higher than those in pre-dialysis patients [(51.71 +/- 15.53) micromol/L, P < 0.01]. AOPP levels increased with the progression of renal dysfunction and inversely correlated with creatinine clearance (Ccr) (r = -0.292, P < 0.05). Patients with carotid artery plaques showed significantly higher levels of AOPP [(73.87 +/- 19.40) micromol/L] as compared with patients without carotid artery plaques [(58.41 +/- 16.09) micromol/L, P < 0.01]. Serum levels of AOPP were strongly associated with carotid artery IMT (r = 0.332, P < 0.01) and cIM area (r = 0.288, P < 0.05). By stepwise multiple regression analysis and adjusting for age, gender, blood pressure, smoking, diabetes, body mass index (BMI), hemoglobin, lipid and albumin, strong association was still present between AOPP levels and carotid artery IMT (beta = 0.313, P < 0.001) and cIMarea (beta = 0.301, P < 0.01). Serum levels of AOPP were correlated positively with serum MDA (r = 0.300, P = 0.01) and CRP levels (r = 0.255, P < 0.05), while negatively with serum GSHPx (r = -0.647, P < 0.01).
Conclusions: Serum levels of AOPP increased with the progression of renal failure and closely associated with occurrence of atherosclerosis. Strong association between serum AOPP and CRP suggests that AOPP might be involved in the pathogenesis of micro-inflammation which has been considered as a contributing factor for atherosclerosis in CKD.