Levels of renalase and advanced oxidation protein products with regard to catecholamines in haemodialysed patients

The main mediators of the sympathetic nervous system in the effectors part are catecholamines (CA). An increased sympathetic nerve activity observed in chronic kidney disease (CKD), is due to a raised level of CA in plasma. Renalase is a protein secreted by the kidneys, composed of 342 amino acids, which is able to metabolize the circulating CA and possibly play an important role in the regulation of sympathetic tone and blood pressure. Also, oxidative stress, defined as a disruption of the equilibrium between the generation of oxidants, is a crucial factor in the development of the inflammatory syndrome associated with CKD. The advanced oxidation protein products (AOPP) represent exquisite markers of phagocyte-derived oxidative stress. The aim of the study was to investigate the concentration of renalase and explore the associations between AOPP with regards to CA in haemodialysis (HD) patients. The study was conducted among 50 residents of the municipality and neighbouring villages in the province of Lublin, central-eastern Poland. In the studied patients, it was found that an average concentration of renalase was 44.8 ± 6.5 μg/mL, whereas of AOPP plasma levels - 57.5 ± 21.5 μmol/L. The results demonstrated the correlation between levels of renalase and AOPP in the HD patients. Indeed, elevated levels of renalase and AOPP in HD may be due to the presence of uremic toxins in blood. The concentration of urea affects the plasma concentrations of AOPP and renalase causing a direct relationship between renalase and AOPP. However, there is no clear relationship between renalase and circulating catecholamines in HD patients.