Apelin in hemodialysis patients: is there relationship with oxidative and inflammation markers?

Inflammation and oxidative stress are importante features associated with pathogenesis of cardiovascular disease in hemodialysis (HD) patients. Apelin is a bioactive peptide involved in a variety of physiological functions that has been associated with inflammation, however; little is known about apelin in chronic kidney disease (CKD). Thus, the purpose of this study was to analyse apelin plasma levels in HD patients and verify if there is any relationship with inflammation and oxidative markers. Twenty-four HD patients (53.6±14.4 years of age, 14 men and body mass index (BMI) of 25.0±4.2kg/m2) were studied and compared to 15 healthy subjects (51.3±13.5 years of age, 7 men and BMI of 26.3±3.7kg/m2). Plasma apelin-12 and -36 were measured using the enzyme immunometric assay (EIA) method. Plasma electronegative low density lipoprotein (LDL-) levels were measured using ELISA method. The levels of tumor-necrosis factor-α (TNF-α), interleukin-6, leptin and plasminogen activator inhibitor-1 were measured by a multiplex assay kit and C-reactive protein (CRP) by immunoturbidimetry. There was no difference between apelin-36 levels in HD patients (0.82±0.60ng/mL) and healthy subjects (0.83±0.23ng/mL). In contrast, apelin-12 levels were significantly higher in patients, 0.34 ±0.15ng/mL than in healthy subjects, 0.24±0.13ng/mL. Inflammation (TNF-α and CRP) and oxidative markers levels (LDL-) were higher in HD patients (5.4±1.3pg/mL, 0.15 (0.33)mg/dL and 0.19±0.13U/L, respectively); however, there was not correlation among apelin-12 or -36 and inflammatory or oxidative markers. In conclusion, plasma apelin seems to be not associated with inflammatory and oxidative status in HD patients