Type 1 diabetics: Polymorphonuclear leukocyte membrane fluidity and cytosolic Ca2+ concentration at baseline and after chemotactic activation

In a group of 32 type 1 diabetics (23 males and 9 females) we evaluated at baseline PMN membrane fluidity (obtained by marking intact and unstimulated PMN cells with the fluorescent probe 1-[4-(trimethylamino)phenyl]-6-phenyl -1, 3, 5-hexatriene [TMADPH]) and PMN cytosolic Ca2+ concentration (obtaine d by marking intact and unstimulated PMN cells,vith the fluorescent probe F ura 2-AM) while in a group of 21 type 1 diabetics (15 males and 6 females) the same PMN parameters were examined at baseline and after activation (pro longed for 5 and 15 min) with 4-phorbol U-myristate 13-acetate (PMA) and N- formyl-methionyl-leucyl-phenylalanine (fMLP). PMN membrane fluidity but not PMN cytosolic Ca2+ concentration distinguishes normals from type 1 diabeti cs. No correlation was seen between these PMN parameters in normals and typ e 1 diabetics nor were significant relationships found between PMN membrane fluidity and cytosolic Ca2+ concentration with plasma parameters (serum gl ucose, cholesterol and triglycerides), In type 1 diabetics, after activatio n with both agents, the behaviour of the PMN membrane fluidity and cytosoli c Ca2+ concentration is different from normals. These data may be a marker of neutrophil dysfunction, more evident after in vitro activation.