Evaluation of circulating microvesicles and their procoagulant activity in patients with COVID-19.

OBJECTIVE: Several pathological conditions trigger the formation of microvesicles (MVs), including infectious diseases such as COVID-19. The shedding of MVs increases the levels of inflammatory factors (e.g., interleukin-6; IL-6) and ultimately leads to an inflammatory cascade response, while also increasing the procoagulant response. The current study aimed to evaluate the level of circulating MVs and their procoagulant activity as well as the serum level of IL-6 in patients with COVID-19 and healthy controls. In this case-control study, 65 patients with COVID-19 and 30 healthy individuals were sampled after obtaining written informed consent. MVs counting was measured using conjugated CD61, CD45, CD235a, and Annexin-V antibodies. Additionally, the procoagulant activity of MVs and the IL-6 level were estimated using enzyme-linked immunosorbent assay (ELISA). RESULTS: The majority of MVs were platelet-derived MVs (PMVs). Patients with COVID-19 had significantly higher levels of MVs, procoagulant MVs, and IL-6 compared to healthy controls (p < 0.001). MVs were significantly correlated with procoagulant MVs, D-Dimer levels, fibrinogen, and IL-6, but not with platelet, lymphocyte, and neutrophil counts. CONCLUSION: Elevated levels of procoagulant MVs and their association with inflammatory and coagulation markers in patients with COVID-19 are suggested as a novel circulatory biomarker to evaluate and predict the procoagulant activity and severity of COVID-19.

Association of Circulating Procoagulant Microvesicles with Painful Vaso-Occlusive Crisis in Sickle Cell Disease.

Introduction: Thrombotic complication is one of the features of sickle cell disease (SCD), characterized by appearance of phosphatidylserine on the outer membrane of sickle-shaped red blood cells and most abundantly on membrane protrusions called microvesicles (MVs). However, the exact mechanism by which MVs may enhance coagulant activity in SCD patients has not been fully addressed. The aim of this study was to further investigate the procoagulant activity of circulating MVs in sickle cell crises. Materials and Methods: Subjects included in this cross-sectional study were 47 patients with SCD and 25 normal subjects with written informed consent obtained from all the participants. MV analysis was conducted by using CD61, CD235α, and Annexin-V monoclonal antibodies. The coagulant activity of MVs was determined by an ELISA-based procoagulant activity assay. Results: The majority of MVs were originated from platelets (CD61+) and erythrocytes (CD235+). These MVs demonstrated significantly enhanced levels during the painful crisis when compared with the steady-state period (p < 0.001) and controls (p < 0.001). Also, the procoagulant activity of MVs was significantly higher in crisis compared to those of steady state (p < 0.001) and positively correlated with the number of Annexin-V+ MVs (p < 0.001). Significant correlations were found between erythrocyte-derived MVs with hemolysis marker (r = 0.51, p < 0.001) and the hemoglobin level (r = -0.63, p < 0.001). Conclusion: The numbers of platelet- and erythrocyte-derived MVs are related to painful crisis, and their quantification in SCD may be helpful for identifying cases at increased risk of thrombotic complications.

Platelet-Derived Procoagulant Microparticles as Blood-based Biomarker of Breast Cancer.

OBJECTIVE: Breast cancer is the main cause of cancer death in women worldwide. Elevated plasma levels of circulating cell-derived microparticles (MPs) have been reported in various types of cancer, including breast cancer, with the ability to mediate inflammation and thrombosis. Microparticles are bioactive agents, and it has been suggested that MPs can be used as a diagnostic, prognostic, or therapeutic biomarker in various diseases. The aim of this study was to investigate the levels of platelet-derived MPs (PMPs) in breast cancer patients. MATERIALS AND METHODS: In this case-control study, 30 patients with breast cancer and 20 normal subjects were sampled after obtaining written consent. MPs were isolated from blood samples by centrifugation technique. CD42b and annexin V markers were used respectively for counting PMPs and procoagulant MPs with flow cytometry. RESULTS: Flow cytometry results showed that the number of PMPs and procoagulant annexin V positive MPs was significantly higher in the breast cancer patients than normal subjects (p <0.001). The number of the annexin V MPs differed significantly in patients with high tumor size (T2) compared to the patients with low tumor size (T1) and controls (p <0.001). Significant and positive correlations were found between PMP levels and tissue-based biomarkers, tumor grading, and distant metastasis (p <0.05). Tumor histological type did not correlate with the numbers of PMPs (p=0.065). CONCLUSION: Increased levels of PMPs and activity in terms of hemostasis and having a positive and significant relationship with tumor grading and metastasis may indicate the effective role of PMPs in the pathogenesis and prognosis of breast cancer.