Diabetes mellitus: Polymorphonuclear leukocyte (PMN) filtration parametersand PMN membrane fluidity after chemotactic activation

The goal of this research was to determine leukocyte rheology at baseline a nd after chemotactic activation in type I and type II diabetics. In 19 norm al subjects, 21 type I diabetics, and 16 type II diabetics at baseline and after in vitro chemotactic activation (prolonged for 5 and 15 minutes) with two stimulating agents (4-phorbol 12-myristate 13-acetate [PMA] and N-form yl-methionyl-leucyl-phenylalanine [fMLP]), we evaluated polymorphonuclear ( PMN) filtration parameters (using a St. George filtrometer [Carri-Med, Dork ing, UK] and considering the initial relative flow rate [IRFR] and the conc entration of clogging particles [CPI) and PMN membrane fluidity (obtained b y marking PMNs with the fluorescent probe 1-(4-[trimethylamino]phenyl)-6-ph enyl-1,3,5-hexatriene (TMA-DPH), At baseline, there was a difference betwee n normals and type I and II diabetics for PMN membrane fluidity only. After activation in normals and diabetics of both types, a significant variation was present in PMN filtration parameters (IRFR and CP) at both 5 and 15 mi nutes. In normals, no variation was present in PMN membrane fluidity after activation with PMA or fMLP, After PMN activation, only in type I diabetics was a significant decrease in PMN membrane fluidity present at both 5 and 15 minutes. After PMN activation with either PMA or fMLP in comparison to b asal values, only the mean variation (Delta%) of the IRFR was significantly different between normals, type I diabetics, and type II diabetics at both 5 and 15 minutes. From the data obtained, it is evident that after activat ion, the PMN filtration pattern shows a specific behavior in diabetics of b oth types, while PMN membrane fluidity changes only in type I diabetics. Th e latter finding may be the basis of a metabolic pattern present in PMNs of this type, revealed after in vitro activation. Copyright (C) 1999 by W.B. Saunders Company.