RAT MESENTERIC ARTERIAL BED PERFUSION WITH ΑLFA-HEMOLYSIN (HLYA) TREATED ERYTHROCYTES INDUCES ATP RELEASE AND VESSEL CONTRACTION

MILESI MV, STRINGA P, HERLAX V, LEAL DENIS MF, ENRIQUE NJ, MATE SM, ALVAREZ CL, LEFEVRE SD, OSTUNI MA, SCHWARZBAUM PJ

Simposio; 38th World Congress International Union of Physiological Sciences; 2017

RAT MESENTERIC ARTERIAL BED PERFUSION WITH ΑLFA-HEMOLYSIN (HLYA) TREATED ERYTHROCYTES INDUCES ATPRELEASE AND VESSEL CONTRACTIONMARIA VERONICA MILESI1;PABLO STRINGA1; VANESA HERLAX2; MARIA FLORENCIA LEALDENIS3; NICOLAS JORGE ENRIQUE1; SABINA MARIA MATE2;CORA LILIA ALVAREZ3; SOPHIE DENISSE LEFEVRE4; MARIANOANIBAL OSTUNI4; PABLO JULIO SCHWARZBAUM3. 1.INSTITUTO DE ESTUDIOS INMUNOLÓGICOS Y FISIOPATOLÓGICOS (IIFP,CONICET?UNLP, LA PLATA - ARGENTINA; 2.INSTITUTO DE INVESTIGACIONES BIOQUÍMICASDE LA PLATA (INIBIOLP) CONICET - UNLP, LA PLATA - ARGENTINA; 3.INSTITUTO DEQUÍMICA Y FISICO-QUÍMICA BIOLÓGICAS (IQUIFIB) CONICET - UBA, CAPITAL FEDERAL -ARGENTINA; 4.UMR-S1134, INTEGRATED BIOLOGY OF RED BLOOD CELLS, INSERM,UNIVERSITÉ PARIS DIDEROT, SORBONNE, PARIS - FRANCA. AbstractWe have previously demonstrated that morphological and rheological propertiesof human erythrocytes change when they were exposed to the α -hemolysin toxin (HlyA), released by uropathogenic strains of E. coli.Particularly, HlyA treated erythrocytes (HlyA-RBC) showed increased membranefragility and swelling, together with an enhanced ATP release and significanthemolysis. Since the resulting extracellular released ATP is a potentialmodulator of vascular resistance (VR), we decided to test the effect ofcontinuous perfusion of RBCs exposed to HlyA or ProHlyA (the non-hemolytic formof HlyA) on the mesenteric arterial bed pressure (MABP) with the aim to observethe effects of RBC alterations on a physiological in vitro model of peripheralresistance. Methods: The small intestinal (jejunum and ileum) with the vascularpedicle was isolated from rats and the superior mesenteric artery and theportal vein were cannulated for vascular perfusion. Krebs Ringer solution (KRS,37ºC) was perfused at 1 ml/min and MABP was measured continuously by means of apressure transducer connected to the arterial inflow line. After organstability, RBC suspension (10% hematocrit in KRS) was perfused at the samerate, and the MABP was monitored. Then the preparation was washed with KRS andsubsequently perfused with HlyA- or ProHlyA-RBC. In each condition a sample ofthe solution leaving from portal vein was taken at 2-min intervals and ATP wasimmediately measured by a luminescence technique. The same protocol wasperformed in the presence of 100 µM suramin (a non-selective purinergicreceptor blocker). Results: i. perfusion of HlyA-RBC increased MABP value (205± 77 % n=7 p<0.05) compared with RBC, while the values measured with HlyA-RBC+ suramin, and Pro HlyA-RBC were not different of that obtained with RBC.Consistent with these results, the highest ATP values were measured in thesamples from Hyla-RBC in a range of 4.41 to 54.07 n=3) compared with thosemeasured with only RBC (ATP values in a range of 0.09 to 1.18 µM n=3).Conclusion: Perfusion of Hlya-RBC suspension induces intravascular ATP release,which activates purinergic receptors that mediate contraction of the mesentericblood vessels. Thus, uropathogenic E. coli infections could have a relevantimpact on arterial blood pressure by changes on peripheral resistance