Acute ischemic stroke - Polymorphonuclear leukocyte membrane fluidity and cytosolic Ca2+ concentration at baseline and after chemotactic activation

Background and Purpose-Several reports have considered the role of systemic leukocytes in acute ischemic stroke (AIS). initially, greater attention wa s focused on the leukocyte count and subsequently on their adhesiveness, ag gregation, rheology, and activation. The aim of this study was the evaluati on of certain polymorphonuclear leukocyte (PMN) parameters, reflecting thei r rheology and activation, in subjects with AIS. Methods-In a group of 19 subjects with AIS and in a control group of 18 sub jects with asymptomatic vascular atherosclerotic disease, we evaluated the PMN membrane fluidity and cytosolic Ca2+ concentration at baseline and afte r in vitro chemotactic activation with 4-phorbol 12-myristate 13-acetate (P MA) and N-formyl-methionyl-leucyl-phenylalanine (fMLP). Results-From the obtained data, it is evident that at baseline only PMN mem brane fluidity distinguishes control subjects from AIS subjects. After PMN activation with PMA and fMLP, prolonged for 5 and 15 minutes, we found an i ncrease in PMN cytosolic Ca2+ concentration and a decrease in PMN membrane fluidity only in subjects with AIS. Conclusions-These findings emphasize that in subjects with AIS a functional alteration of systemic PMN cells is clearly expressed during chemotactic a ctivation, although the mechanism of this abnormality is not yet explained.