Detection of monocyte-derived microparticles in patients with Type II diabetes mellitus

Abstract

Aims/hypothesis: The role of plasma monocyte-derived microparticles (MDMPs) and platelet-activation markers (platelet-derived microparticle [PDMP], platelet-bound CD62P [plt-CD62P], and platelet-bound CD63 [plt-CD63]) in diabetic vascular complications is not clear. We measured and compared plasma concentrations of MDMPs and the platelet-activation markers to investigate their possible contribution to diabetic vascular complications.

Methods: Activated platelets and microparticles (PDMP and MDMP) were analysed by flow cytometry. Concentrations of serum sE-selectin were measured with enzyme-linked immunosorbent assay.

Results: The concentration of MDMPs in diabetic patients was higher than in normal subjects. We found no differences in the binding of anti-GPIIb/IIIa and anti-GPIb monoclonal antibodies between groups. There were differences, however, in the concentrations of PDMPs, plt-CD62P, and plt-CD63 between Type II (non-insulin-dependent) diabetes mellitus patients and control subjects (PDMPs: 585 +/- 25 vs 263 +/- 9, p < 0.01; plt-CD62P: 28.1 % +/- 1.4 % vs 9.4 % +/- 0.6 %, p < 0.001; plt-CD63: 28.1 % +/- 1.4 % vs 8.6 % +/- 0.5 %, p < 0.001). Amounts of MDMPs correlated positively with these platelet activation markers, and the relation between PDMP and MDMP was the most significant. The concentration of MDMP in patients who had diabetes complicated with nephropathy, retinopathy, or neuropathy was higher than in those without diabetes-related complications. The increase in MDMP was particularly significant in patients with nephropathy. Concentrations of sE-selectin were higher in Type II diabetes patients than in control subjects, and correlated with MDMP, PDMP, plt-CD62P, and plt-CD63 levels in nephropathy patients.

Conclusion/interpretation: In Type II diabetes patients, we detected increased activation of monocytes, which could have been stimulated by activated platelets and PDMPs. Because the activation of monocytes is associated with vascular endothelial damage, high concentrations of MDMPs could indicate vascular complications in diabetes patients, especially those who have diabetes-related nephropathy.