Endothelial Cell‐, Platelet‐, and Monocyte/Macrophage‐Derived Microparticles are Elevated in Psoriasis Beyond Cardiometabolic Risk Factors

BACKGROUND: Psoriasis, especially when severe, is a risk factor for cardiometabolic disease beyond traditional risk factors. The mechanism of atherogenesis in psoriasis remains unknown. Cell membrane vesicles (ie, microparticles), released upon cell activation or apoptosis, have recently been associated with cardiometabolic disease and may play a pathogenic role. Microparticle levels, particularly from endothelial cells and platelets, are elevated in patients with cardiovascular disorders, metabolic syndrome, other inflammatory diseases, autoimmune conditions, and have been shown to be predictive of cardiovascular outcomes. METHODS AND RESULTS: Concentrations of microparticles with positive expression for any of 7 cell surface markers (Annexin V, CD3, CD31, CD41a, CD64, CD105, and CD144) were measured in blood samples from psoriasis patients (n=53) and control subjects without psoriasis (n=41). Platelet‐free plasma was separated from whole blood by one‐step centrifugation for microparticle analysis. Microparticles were fluorescently labeled and characterized by flow cytometry. Higher concentrations of CD105 (5.5/μL versus 2.5/μL, P<0.001), CD31 (31/μL versus 18/μL, P=0.002), CD41a (50/μL versus 22/μL, P<0.001), and CD64 (5.0/μL versus 4.1/μL, P=0.02) singly positive microparticles corresponding to endothelial cell‐, platelet‐, and monocyte/macrophage‐derived microparticles, respectively, were found in psoriasis patients compared with controls. These differences persisted after adjustment for traditional cardiometabolic risk factors including body mass index. CONCLUSIONS: Increased microparticle concentrations, independent of cardiometabolic risk factors, in patients with psoriasis suggest that the presence of increased endothelial cell, platelet, and monocyte/macrophage activation with cell turnover may contribute to the heightened atherogenesis associated with psoriasis.