Elevated levels of platelet microparticles are associated with disease activity in rheumatoid arthritis

Abstract

Objective. Platelets are involved in various thrombotic events, often by means of platelet-derived microparticles (PMPs). It is likely that platelets are also involved in inflammation. Because inflammatory processes play a central role in rheumatoid arthritis (RA), we sought to determine whether PMPs are present in this disease.Methods. This descriptive, cross-sectional study included 19 RA patients and 10 healthy controls. Nine of the patients had active RA (erythrocyte sedimentation rate [ESR] >28 mm/hour and/or C-reactive protein [CRP] level >28 mg/liter, >9 painful joints, and >6 swollen joints), and 10 had inactive disease (ESR <27 mm/hour, CRP <27 mg/liter, no tender joints, and no swollen joints). Platelet counts and PMP numbers were determined using cell counter and flow cytometry, respectively.Results. Platelet counts in the 3 groups were similar. However, levels of PMPs in RA patients were significantly higher than those in healthy controls (median 616 versus 118 ؋ 10 6 /liter; P ‫؍‬ 0.005). PMP levels were higher in patients with active RA than in those with inactive RA (median 2,104 versus 504 ؋ 10 6 /liter; P > 0.05). Moreover, PMP levels correlated with disease activity (r ‫؍‬ 0.67, P ‫؍‬ 0.05).

Altered profile of circulating microparticles in rheumatoid arthritis patients

“…In line with our results, other studies performed with RA patients showed increased MP counts, total or specific from different cell subsets and associated with some clinical features [27][28][29]. However, evidence is limited and results are heterogeneous and even contradictory, probably because of the different methodologies used.…”

“…Hence, we could attribute these results to the analysis performed in our study. In fact, increased PMP counts in RA were observed when annexin-V binding was used [28,29], however, when alternative procedures were performed, opposed results were achieved [19,29]. This lead us to hypothesize that the total labelling protocol performed in this work could mask the differences in Annexin V-positive PMPs due to an elevated number of negative-events.…”

Increased circulating platelet–neutrophil, platelet–monocyte complexes, and platelet activation in patients with ulcerative colitis: A comparative study

“…However, more studies should be conducted to prove the association of the increase in these parameters with clinical thrombotic events. It was stated that PMP increased with platelet activation and it was related with CD62P expression [18,22]. In addition, it was suggested that PMP increased thrombin formation, the adhesion of leukocytes onto vascular surfaces, and played roles in thromboembolic events by stimulating leukocyte-leukocyte and leukocyte-platelet interactions [23,24].…”

“…In addition, it was suggested that PMP increased thrombin formation, the adhesion of leukocytes onto vascular surfaces, and played roles in thromboembolic events by stimulating leukocyte-leukocyte and leukocyte-platelet interactions [23,24]. Some studies reported an association between the level of PMP and the development of thromboembolic, atherosclerotic events [18,22,25]. In one recent study, it was reported that PMPs were increased in active UC and that their levels correlated with CAI and sP-selectin [12].…”

Platelet and red blood cell interactions and their role in rheumatoid arthritis

“…Hyperactive platelets and their products are found in higher proportions at inflammatory sites than in circulation [72]. While inflammatory pathways differ from haemostatic, they share several common mediators that may cause platelet functions to overlap [73].…”