Apelin: A Peptide Involved in Cardiovascular Risk in Hemodialysis Patients?

Abstract

Inflammation, oxidative stress, and obesity are important features associated with pathogenesis of cardiovascular disease, a major contributor to the mortality of hemodialysis (HD) patients. Apelin is an adipokine involved in a variety of physiological functions; however, little is known about apelin in chronic kidney disease (CKD). Thus, the purpose of this study was to analyze apelin plasma levels in HD patients and verify whether there is any relationship with inflammation, oxidative markers, and obesity. Twenty-four HD patients [53.6 AE 14.4 years, 14 men, and body mass index (BMI) of 25.0 AE 4.2 kg/m 2 ] were studied and compared with 15 healthy subjects (51.3 AE 13.5 years, 7 men, and BMI of 26.3 AE 3.7 kg/m 2 ). Plasma apelin-12 and -36 were measured using the enzyme immunometric assay method. Plasma electronegative lowdensity lipoprotein [LDL(-)] levels were measured using ELISA method, and tumor necrosis factor-α, interleukin-6, leptin, and plasminogen activator inhibitor-1 levels were measured by a multiplex assay kit. C-Reactive protein (CRP) was determined by immunoturbidimetry. Anthropometric data were also evaluated. There was no difference between apelin-36 levels in HD patients (0.82 AE 0.60 ng/mL) and healthy subjects (0.83 AE 0.23 ng/mL). In contrast, apelin-12 levels were significantly higher in patients (0.34 AE 0.15 ng/mL vs. 0.24 AE 0.13 ng/mL in healthy subjects). TNF-α, CRP, and LDL(-) levels were higher in patients; however, there was no correlation among apelin-12 or -36 and inflammatory or oxidative markers. The adiposity parameters were also not associated with apelin-12 or -36. In conclusion, plasma apelin seems to be not associated with cardiovascular risk in HD patients.

Apelin and nutritional status in children on dialysis

“…27 On the other hand, in support to our results, three recent papers did not show a difference between apelin in dialysis patients and healthy individuals. [28][29][30] The discrepancy between previous and the latest reports might be due to various factors influencing apelin production/release and removal or the methodological heterogeneity of the studies. In accordance with Karadag et al, 31 we also found age was inversely correlated with serum apelin levels.…”

“…In the current study, apelin was positively correlated with ESR and CRP in children on PD and HD. Malyszko 27,28 These different results might be related with changes in the inflammatory profile of PD, HD, adult and pediatric populations.…”

“…Likewise, Mafra et al and Leal et al did not find an association between apelin and adiposity markers. 28,29 These evidences suggested apelin might not be a useful indicator of nutritional status in children on dialysis.…”

Serum level of apelin-13 negatively correlated with NT-proBNP in heart failure patients

“…It seems to be a guardian of the living organism, human or animal, which regulates basic functions of the systems and tissues, helps in the process of recovery after an injury and appears to delay the onset of diseases. Although some of the results reported so far give apelin anti-inflammatory properties, the exogenous administration of apelin being able to lower the inflammatory factors such as tumor necrosis factor (TNF ) and interleukin 1 (IL-1 ) [17,18], its level being increased after lowering the cholesterol level by dietary or pharmacological measures [19] or being in reverse relationship with the level of inflammation in the body [8], other studies do not have such clear results about its relationship with the inflammatory markers [20,21]. This is probably due to the complex actions exerted by apelin and its receptor in vivo compared with in vitro conditions.…”

Untitled

“…A role of the kidney in metabolizing apelin has not been investigated. 13 Yilmaz and associates found that endothelial dysfunction in type-2 diabetics with early diabetic nephropathy is associated with low circulating adiponectin. Also, apelin receptor mRNA and protein expression significantly decreased in both ischemic and nonischemic kidneys experimentally.…”