Increased platelet activation markers in rheumatoid arthritis: Are they related with subclinical atherosclerosis?

Atherosclerotic cardiovascular mortality is increased in rheumatoid arthritis (RA) patients. We evaluated the association of inflammatory response with platelet, endothelial, coagulation activation parameters; and subclinical atherosclerosis in RA patients. We included 27 RA patients (21 female; six male) and 19 healthy subjects (14 female; five male). Disease activity score (DAS28) in RA patients was calculated; and patients were divided into two groups as active and inactive. Flow cytometry was used to determine platelet CD62P expression, platelet microparticles (PMP), platelet-monocyte (PMC) and platelet-neutrophil complexes (PNC). Plasma E-selectin, thrombin-antithrombin (TAT) complex, and serum sCD40L levels were determined by ELISA. The intima-media thickness (IMT) of carotid arteries was determined by B-mode ultrasonography. In RA patients, platelet CD62P expression (p< 0.001), PMC (p = 0.037) and sCD40L (p< 0.001) levels were increased when compared to the control group. PNC (p = 0.07) and TAT levels (p = 0.1) were non-significantly higher, and PMP level (p = 0.075) was nonsignificantly lower in RA patients. Soluble E-selectin level was significantly higher in the active RA group than in the inactive RA group (p = 0.009). There was no correlation between carotid IMT and activity markers, the evaluated parameters (p>0.05).The increase in markers of active platelets, CD62P and sCD40L, and PMC levels might be associated with the increased cardiovascular mortality in RA. Nevertheless, none of these parameters were associated with carotid IMT: this suggests that one cross-sectional value might not be a good marker for atherosclerosis.