Differences in AQP1 and AQP4 localization and modulation in the heart of adult patients undergoing aortic valve replacement surgery

MARIA TERESA POLITI; FEDERICO OCHOA; VANINA NETTI; RAUL FERREYRA; GUILLERMO BORTMAN; CELINA MORALES; ANTONIO PIAZZA; CLAUDIA CAPURRO

Mar del Plata

Congreso; Congreso de la Sociedad Argentina de Fisiología (SAFIS); 2018

Sociedad Argentina de Fisiología (SAFIS)

Title: Differences in AQP1 and AQP4 localization and modulation in the heart of adult patients undergoing aortic valve replacement surgeryAuthors: María Teresa Politi1, Federico Ochoa2, Vanina Netti1, Raúl Ferreyra3, Guillermo Bortman3, Celina Morales4, Antonio Piazza3, Claudia Capurro11: Universidad de Buenos Aires, Facultad de Medicina, IFIBIO Houssay, Laboratorio de Biomembranas.2: Universidad de Buenos Aires, Facultad de Medicina, IFIBIO Houssay, Laboratorio de Fisiopatología.3: Departamento de Cardiología, Sanatorio de la Trinidad ? Mitre.4: Universidad de Buenos Aires, Facultad de Medicina, Laboratorio de Fisiopatología Cardiovascular.Background: Cardiopulmonary bypass (CPB) is an essential strategy in heart valve replacement surgery; however, it may produce myocardial edema and dysfunction. Aquaporins (AQP) 1 and 4 are selective water channels found in myocardial tissue. In animals, AQP1 increases after CPB and possibly produces myocardial edema. In human subjects information is still scarce. We designed an observational study to evaluate changes in AQP1 and 4 expression after CPB using myocardial biopsies from adult patients undergoing aortic valve replacement surgery. Our previous results suggest that AQP1 expression increases after CPB, while AQP4 expression decreases. The goals of this study are: 1) To identify the cellular localization of AQP1 and 4; 2) To explore possible candidates that may explain changes in AQPs expression during CPB. Methods: 15 patients undergoing aortic valve replacement surgery were enrolled. Biopsies were taken from the anterior wall of the left ventricle before and after CPB using an automatic transmural fine-needle. Immunohistochemistry was performed using anti-AQP1 and anti-AQP4 antibodies. Data from routine blood tests were collected. Data are expressed as mean ± SEM. Results: Immunohistochemistry staining identified AQP1 expression in the endothelium of myocardial capillaries and AQP4 expression in cardiomyocytes, both before and after CPB. Throughout CPB, there was an increase in calculated plasmatic osmolarity (in mOsm: 287.5±2.8 vs 292.0±1.7; p=0.0346) and glycemia (in mg/dl: 118.9±7.5 vs 194.6±10.5; p