Altered circulating Tregs and their functional cytokines in hypertensive patients with or without left ventricular hypertrophy

Abstract Background:Left ventricular hypertrophy (LVH) is the most common target organ damage in hypertension. In addition to the increased left ventricular afterload, immune injury participates in LVH pathogenesis. CD4+CD25+Foxp3+ regulatory T lymphocytes (Tregs) are a T cell subset with immunomodulatory effects; abnormal Treg numbers or functions can cause immune disorders. This study aimed to explore the role of Tregs in LVH by investigating circulating Tregs and associated cytokine levels in hypertensive patients with LVH.Methods:Blood samples were collected from 69 healthy individuals (control group, CG), 91 hypertensive patients with LVH (LVH group) and 83 hypertensive patients without LVH (essential hypertension, EH group). Circulating Tregs and associated cytokines were measured by flow cytometry and enzyme-linked immunosorbent assays, respectively.Results:Circulating Tregs were significantly lower in EH and LVH patients than in CG subjects. The circulating Treg level was lower in LVH patients than in EH patients. No correlation between blood pressure regulation and Treg levels was found in EH or LVH patients. Furthermore, circulating Tregs in postmenopausal females were lower than those in males among LVH patients. Additionally, serum IL-10 and transforming growth factor (TGF)-β1 were decreased in EH and LVH patients, and the serum IL-6 level was significantly increased in LVH patients. Circulating Tregs were negatively correlated with CK, LDL, apoB, high-sensitivity C-reactive protein and left ventricular mass index values.Conclusion:Our study is the first to demonstrate the significantly decreased circulating Treg proportion in LVH patients. The protective effect of Tregs in LVH is independent of blood pressure regulation. The functional Treg cytokines IL-6, IL-10 and TGF-β1 participate in this immunomodulatory process.Trial registration: The study was approved by the Institutional Medical Ethics Committee of the Second Xiangya Hospital of Central South University (2018/No.046).