Rat mesenteric arterial bed perfusion with alfa-hemolysin (hlya) treated erythrocytes induces ATP release and vessel contraction

STRINGA, PABLO; ENRIQUE, NICOLÁS; LEFEVRE, SOPHIE DENISE; MILESI, MARIA VERÓNICA; LEAL DENIS, MARIA FLORENCIA; ALVAREZ, CORA LILIA; SCHWARZBAUM, PABLO; HERLAX, VANESA; MATE, SABINA; OSTUNI, MARIANO

Rio de Janeiro

Congreso; 38th IUPS Congress (International Union of Physiology Sciences); 2017

IUPS (International Union of Physiology Sciences)

We have previously demonstrated that morphological and rheological properties of 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 membrane fragility and swelling, together with an enhanced ATP release and significant hemolysis. Since the resulting extracellular released ATP is a potential modulator of vascular resistance (VR), we decided to test the effect of continuous perfusion of RBCs exposed to HlyA or ProHlyA (the non-hemolytic form of HlyA) on the mesenteric arterial bed pressure (MABP) with the aim to observe the effects of RBC alterations on a physiological in vitro model of peripheral resistance. Methods: The small intestinal (jejunum and ileum) with the vascular pedicle was isolated from rats and the superior mesenteric artery and the portal 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 a pressure transducer connected to the arterial inflow line. After organ stability, RBC suspension (10% hematocrit in KRS) was perfused at the same rate, and the MABP was monitored. Then the preparation was washed with KRS and subsequently perfused with HlyA- or ProHlyA-RBC. In each condition a sample of the solution leaving from portal vein was taken at 2-min intervals and ATP was immediately measured by a luminescence technique. The same protocol was performed in the presence of 100 µM suramin (a non-selective purinergic receptor blocker). Results: i. perfusion of HlyA-RBC increased MABP value (205 ± 77 % n=7 p