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

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)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 +/- 14.4 years, 14 men, and body mass index (BMI) of 25.0 +/- 4.2 kg/m(2)] were studied and compared with 15 healthy subjects (51.3 +/- 13.5 years, 7 men, and BMI of 26.3 +/- 3.7 kg/m(2)). Plasma apelin-12 and -36 were measured using the enzyme immunometric assay method. Plasma electronegative low-density lipoprotein [LDL(-)] levels were measured using ELISA method, and tumor necrosis factor-alpha, 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 +/- 0.60 ng/mL) and healthy subjects (0.83 +/- 0.23 ng/mL). In contrast, apelin-12 levels were significantly higher in patients (0.34 +/- 0.15 ng/mL vs. 0.24 +/- 0.13 ng/mL in healthy subjects). TNF-alpha, 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.345577581Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Unidade de Pesquisa Clinica (UCP)-HUAP-UFFConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

The Relationship between Apelin and Parathyroid Hormone in Hemodialysis Patients

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Both apelin and parathyroid hormone (PTH) are endogenous ligands for G-protein-coupled receptors. Apelin acts as a mitogenic agent for osteoblasts, and metabolic bone abnormalities are frequently seen in hemodialysis (HD) patients because of hyperparathyroidism. The aim of this study was to analyze plasma apelin levels in HD patients and to determine whether they are related to PTH concentrations. A total of 23 HD patients [15 men and 8 women, with a mean (SD) age of 54.2 (4.4) years and a mean body mass index (BMI) of 25.0 (4.1) kg/m(2)] were studied and compared with 15 healthy subjects [6 men and 9 women, with a mean (SD) age of 51.3 (13.6) years and a BMI of 27.0 (4.3) kg/m(2)]. Plasma apelin-36 was measured using an enzyme immunometric assay method and PTH was measured by ELISA. There was no significant difference in apelin levels between the patients [0.80 (0.6) ng/mL] and the healthy subjects [0.83 (0.23) ng/mL]. There was a positive correlation between apelin and PTH (r = 0.66, p = 0.0001). The patients with PTH >300 pg/mL had significantly higher plasma apelin levels [1.17 (0.7) ng/mL] compared with the patients with PTH <300 pg/mL [0.50 (0.15) ng/mL] (p = 0.003). In conclusion, HD patients with secondary hyperparathyroidism have high plasma apelin levels, which suggest that apelin may protect bone in HD patients by acting as an osteoblastic factor.348970973Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq