Effects of Curcumin on miR-21/Tregs and IL-6 in PBMCs From Patients With Myocardial Infarction

The present study aimed to evaluate the effects of curcumin on the percentage of Tregs as well as miR-21 gene expression and IL-6 levels in peripheral blood mononuclear cells (PBMCs) in patients experiencing myocardial infarction (MI) compared to the controls. Isolation of PBMCs was performed from the peripheral blood of the subjects of the studied groups (50 patients with MI as a case group, and 50 controls). The effects of the low doses of curcumin (0.1 and 1 µM, for 48 h) on the studied parameters were evaluated and compared to the positive and negative controls in vitro. Flow cytometry analysis was used to determine the percentages of regulatory T cells. For gene expression measurement and cytokines assay, Real-time PCR and ELISA were carried out. The proportion of regulatory T cells was markedly lower in PBMCs from patients with MI (P = .03) compared to the controls. microRNA (miR)-21 expression (P = .01) was decreased while the serum level of IL-6 was increased (P = .008) in PBMCs from patients with MI compared to the controls. In vitro, curcumin treatment improved the percentage of Tregs (P =.02) while decreasing miR-21 expression (0.03) and the IL-6 level (P = .02) in PBMCs isolated from patients with MI when compared to untreated cells. The present study provided new insights into the mechanism of the anti-inflammatory effect of curcumin by affecting miR-21/Tregs in MI. Therefore, curcumin may be effective in the improvement of cardiac injury after MI through immunomodulatory mechanisms.