Cardiovascular risks in hemodialyzed patients: could apelin have a role?

ABSTRACT

Apelin is a newly discovered adipocytokine and is produced by the white adipose tissue but is expressed, to a lesser extent in the kidney and heart. Apelin has recently been shown to be a potent positive inotropic agent in normal hearts. In addition, there is increasing evidence suggesting the role of apelin in the pathology of cardiovascular system. Cardiovascular disease is known to be a major contributor to the mortality and morbidity in patients with chronic renal failure. The aim of this study was to determine the apelin level in hemodialyzed patients and to assess its association to echocardiographic parameters among these patients. Forty uremic patients on maintenance hemodialysis were included in this study and compared with age and sex matched forty control subjects. Plasma apelin level, plasma nitrates and nitrites and routine biochemical investigations together with echocardiography were done for all subjects. Patients on hemodialysis showed significant lower level of apelin as compared to control group [5.59 +/- 2.97, 8.60 +/- 0.97 respectively, p<0.001]. Left ventricular internal end-diastolic dimension [LVIDd], Left ventricular internal end-systolic dimension [LVISd], interventricular septal thickness [IVS] were higher significantly among patients compared to control [p<0.001, <0.001, 0.02 respectively]. There was significant negative correlation between plasma apelin level and both LVIDd [p=0.003] and LVISd [p=0.046], suggesting the inotropic role of apelin. There was significant positive correlation between plasma apelin level and both plasma nitrates and nitrites [p<0.001] suggesting that apelin may mediate its effect via nitric oxide. Apelin level was significantly lower in hemodialysis patients. Apelin may be involved pathophysiology of cardiovascular disease in chronic renal failure. The therapeutic role of apelin as inotropic agent in uremic patients is to be investigated