Apelin Receptor (APJ) Expression during Cardiopulmonary Bypass in Children Undergoing Surgical Repair

Abstract

Background and AimsIn human adults, and animals, the Apelin-APJ ligand-receptor system is emerging as having a role in the pathogenesis of cardiovascular function and heart failure. The aim was to investigate expression, and regulation by oxygen, of the Apelin APJ receptor (APJ) in myocardium obtained from children undergoing corrective surgery with cardiopulmonary bypass for repair of congenital heart defects.MethodsWestern blotting and Real-time PCR were used to determine if APJ was expressed in the infant myocardium, if expression was influenced by the duration of myocardial ischemia and if any relationship existed between APJ expression and early post-operative outcome. The next aim was to determine if there was a difference in mRNA expression of APJ in myocardium from cyanotic patients compared with acyanotic patients and if re-perfusing myocardium in vitro with either hypoxic, normoxic or hyperoxic oxygen affected APJ mRNA expression.ResultsAPJ was expressed in all myocardial samples and myocardium exposed to longer durations of ischemia and cardioplegia expressed higher levels of APJ (p<0.05). There was a significant correlation between APJ expression in myocardium resected after 10 min with both oxygen extraction ratio (p = 0.021, rho = −0.523) and mixed venous oxygen saturation (p = 0.028, rho 0.52). This association did not exist for myocardium collected before 10 min. There was no difference in APJ expression between cyanotic and acyanotic patients. No difference was found in APJ expression whether re-perfused with low, normal or high oxygen.ConclusionsChanges in APJ expression were observed during cardiopulmonary bypass in children and the reasons for this require further investigation.

Load-dependent effects of apelin on murine cardiomyocytes

“…Apelin orthologues are present in many species including pig, rhesus macaque, cow and zebrafish. Apelin and apelin receptor have been shown previously to be expressed in cardiomyocytes of human ( Kleinz et al., 2005 , Walker et al., 2014 ) and rodents ( Ronkainen et al., 2007 , Kawamata et al., 2001 ). Apelin is synthesised as pre-proapelin, a 77 amino acid pre-proprotein ( Tatemoto et al., 2001 ).…”

Apelin Is a Prototype of Novel Drugs for the Treatment of Acute Myocardial Infarction and Adverse Myocardial Remodeling

“…The endogenous agonist of the apelin receptor apela mRNA was detected in the rat heart [ 18 ]. It was demonstrated that the apelin receptor is expressed in the atrial tissue and heart ventricles of rats [ 25 ] and in the human heart [ 26 ]. The apelin receptor was identified in the epicardial coronary arteries of rats [ 27 ].…”

Apelin-12 and its receptor as diagnostic biomarkers of childhood and adult diseases

“…na aktywacji receptora naskórkowego czynnika wzrostu i fosfatazy [48,51,52]. Zmiany w ekspresji receptora APJ w układzie sercowo-naczyniowym badano także u dzieci poddanych operacjom kardiochirurgicznym z powodu wad serca, jednak wyniki nie były jednoznaczne [53].…”