Background: Takayasu Arteritis (TA) is a chronic inflammation involving the aorta and its main branches, often leading to a combination of dilatation and secondary thrombus formation. However, the diagnose of active stage remains an issue. Microparticles (MPs) are membrane-bound vesicles derived from vascular and intravascular cells such as platelets (PMPs) and endothelial cells (EMPs), and are elevated in patients with cardiovascular disorders, metabolic syndrome, other inflammatory diseases, and autoimmune conditions.
Objective: Characterization of the abundance and origin of circulating MPs in TA patients and healthy controls and to determine any associations with disease activity.
Methods: We analyzed MPs isolated from the plasma of 32 TA patients, including 14 active stage patients and 18 healthy subjects by flow cytometry using AnxV and antibodies to platelet and endothelial cell surface markers.
Results: Active TA patients had increased concentrations of total MPs (p=0.0289) and Anx V- MPs (p=0.035) compared with stable ones. In the subgroup of Anx V- MPs and Anx V+ MPs, significance increased concentrations of Anx V+ EMPs (p=0.0319), Anx V- MPs from unknown nature (p=0.0195) and Anx V- EMPs (p=0.0066) were observed in active patients compared with stable patients. There were no significant differences between stable patients and healthy subjects. With receiver operating characteristic (ROC) curve, we analyzed the association between Anx V- MPs and disease activity (area under curve [AUC]=0.786; 95% confidence interval [CI]: 0.618~0.953; P=0.006.).
Conclusion: The concentrations and composition of MPs in active TA patients differ significantly from those in stable ones. Anx V- MPs might be considered to be a biomarker of disease activity. These findings call for further study on the role of MPs on TA pathogenesis.