Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 19 4 2024 10 30 256 263 Achmad Lefi Department of Cardiology and Vascular Medicine, Faculty of Medicine Universitas Airlangga-Dr. Soetomo General Hospital, Surabaya, Indonesia. Denisa Asmarani Department of Cardiology and Vascular Medicine, Faculty of Medicine Universitas Airlangga-Dr. Soetomo General Hospital, Surabaya, Indonesia. Budi Dharmadjati Department of Cardiology and Vascular Medicine, Faculty of Medicine Universitas Airlangga-Dr. Soetomo General Hospital, Surabaya, Indonesia. Denny Suwanto Department of Cardiology and Vascular Medicine, Faculty of Medicine Universitas Airlangga-Dr. Soetomo General Hospital, Surabaya, Indonesia. Mahendra Saputra Department of Cardiology and Vascular Medicine, Faculty of Medicine Universitas Airlangga-Dr. Soetomo General Hospital, Surabaya, Indonesia. Vemaniarti Pravitasari Department of Cardiology and Vascular Medicine, Faculty of Medicine Universitas Airlangga-Dr. Soetomo General Hospital, Surabaya, Indonesia. Faizal Anandita Department of Cardiology and Vascular Medicine, Faculty of Medicine Universitas Airlangga-Dr. Soetomo General Hospital, Surabaya, Indonesia. 2024 05 07 2024 10 19 Background: Rheumatic heart disease (RHD) is exacerbated by chronic inflammation that stimulates the release of proinflammatory cytokines, most notably transforming growth factor-beta 1 (TGF-β1), which promotes myofibroblast differentiation. This study aims to determine the optimal dosage of Lisinopril, an angiotensin-converting enzyme inhibitor, for mitigating the fibrotic changes associated with RHD. Methods: This in vitro, posttest-only control group study involved obtaining valvular interstitial cells from the heart valves of 25 male New Zealand rabbits (Oryctolagus cuniculus). Valvular interstitial cells were divided into 5 groups: a control group exposed to TGF-β1, and 4 experimental groups exposed to various Lisinopril doses (1 µM, 10 µM, and 100 µM) in addition to TGF-β1. The effect of Lisinopril on myofibroblast differentiation was assessed by measuring alpha-smooth muscle actin (αSMA) expression through immunocytochemical methods. Statistical significance was determined using an independent T-test with a P value of less than 0.050. Results: Independent T-tests conducted on 25 male Oryctolagus cuniculus demonstrated significantly lower αSMA expression in the groups treated with various Lisinopril doses (1 µM, 10 µM, and 100 µM) compared with the TGF-β1-induced control group (P<0.050). The most significant reduction in αSMA expression was observed in the group treated with the highest Lisinopril dose of 100 µM. Conclusion: Lisinopril demonstrates a significant ability to inhibit TGF-β1-induced myofibroblast differentiation in rabbit valve interstitial cells, with the 100 µM dose proving most effective. These results suggest that Lisinopril may have the potential to curb RHD progression, warranting further investigations in vivo. https://rhythm.tums.ac.ir/index.php/jthc/article/view/2091