Polymorphonuclear leukocyte membrane fluidity and cytosolic Ca 2+ concentration in subjects with vascular atherosclerotic disease subdivided according to its extent

An abnormal activation state of polymorphonuclear leukocytes (PMN) plays a key role in organ injury induced by vascular atherosclerotic disease (VAD) and diabetes mellitus (DM). PMN membrane fluidity and cytosolic Ca²⁺ content can be considered markers of PMN activation. In this research we evaluated the PMN membrane fluidity and cytosolic Ca²⁺ content in VAD subjects with and without type 2 DM and examined the association between these parameters and the mono- or polyvascular localization. We enrolled 155 VAD subjects, including 92 non-diabetic (group A: mean age 63.6±9.2 years) and 63 diabetic patients (group B: mean age 65.4±7.8 years). Among group A 63 patients had monovascular and 29 polyvascular disease; among group B 30 patients had monovascular and 22 polyvascular disease. In each patient we evaluated the PMN membrane fluidity labelling the cells with the fluorescent probe 1,4-(trimethylamino)-phenyl-4-phenylhexatriene (TMA-DPH) and the PMN cytosolic Ca²⁺ content marking the cells with the fluorescent probe Fura 2-AM. PMN membrane fluidity did not discriminate normal subjects from diabetic and non-diabetic VAD subjects, while cytosolic Ca²⁺ content was increased in both groups. PMN membrane fluidity did not distinguish normal subjects from mono- or polyvascular VAD patients with and without type 2 DM. PMN cytosolic Ca²⁺ content was increased especially in monovascular VAD patients; both mono- and polyvascular VAD subjects with DM had a PMN cytosolic Ca²⁺ content higher than normals. Our results show the presence of an increased PMN cytosolic Ca²⁺ content in diabetic and non-diabetic VAD subjects but no association was observed between this increase and the mono- or polyvascular localization.