MiR-21, miR-126 and miR-181b expression in Thromboangiitis obliterans.

Background: Several studies have demonstrated the participation of by-products of the NF-kB pathway in thromboangiitis obliterans, however, the involvement of microRNAs 21, 126 and 181b that are related to this pathway in TAO activation is unknown. Patients and methods: We analyzed the serum levels of miR-21, miR-126 and miR-181b in TAO patients at two times separated by 6 months (TAO-1 and TAO-2 groups) and compared them with three healthy control groups with smokers (SC), former smokers (FSC) and never smokers (NSC). Results: Three patients activated the disease between periods TAO-1 and TAO-2, with elevation of the studied microRNAs. We identified an overexpression of miR-21 in TAO-2 compared to NSC (CI 5.37-21.45; p<0.01); FSC (CI 1.46-18.14; p=0.02) and SC (CI 0.97-16.13; p=0.03). MiR-126 showed overexpression in TAO-2 relative to NSC (CI 3.36-30.95. p=0.02). MiR-181b showed overexpression relative to NSC (CI 0.27-14.18. p=0.04). The groups with a history of smoking had higher means of the microRNAs studied, but without statistical difference. Conclusions: Serum levels of microRNAs 21, 126 and 181b appears to be upregulated in TAO patients and to correlate with periods of greater disease activity, but further studies with a larger number of patients are needed to validate an eventual process of using them as biomarkers of disease activity.