Expression features of miR-155 and miR-28 microRNAs in patients with long COVID and arterial hypertension

Post-COVID syndrome, known as long COVID, is characterized by prolonged systemic inflammation and vascular dysfunction, particularly in individuals with arterial hypertension. MicroRNAs, such as miR-155 and miR-28, are regarded as potential molecular markers of this pathological condition. This study aimed to evaluate the expression patterns of miR-155 and miR-28 in patients with long COVID depending on the presence of hypertension, and to evaluate their associations with markers of inflammation and vascular impairment. A total of 102 patients were examined at least four weeks after recovery from COVID-19. Two groups of patients were formed, i.e., individuals with or without arterial hypertension (respectively, 50 and 52 subjects). Plasma levels of miR-155 and miR-28 were measured using reverse transcription quantitative PCR. General statistical and correlation analyses were performed. The results demonstrated that patients with hypertension exhibited elevated expression of miR-155 and reduced levels of miR-28, along with increased concentrations of inflammatory markers such as C-reactive protein, interleukin-6, B-type natriuretic peptide, and fibrin degradation products. In contrast, normotensive patients showed more stable biomarker profiles. These findings suggest that miR-155 and miR-28 reflect the degree of inflammatory and vascular activation in long COVID. The association between hypertension and dysregulation of these microRNAs highlights their potential utility for risk stratification and post-infection monitoring in affected individuals.