The impact of Sacubitril/Valsartan on cardiac fibrosis early after myocardial infarction in hypertensive rats

Background: Sacubitril/Valsartan, a dual inhibitor of the neprilysin and angiotensin receptor, exerts cardioprotective effects in heart failure. Little is known on the impact of Sacubitril/Valsartan in hypertensive patients early post myocardial infarction. Methods: Spontaneously hypertensive rats (SHR) were pretreated by daily angiotensin receptor blocker (ARB; 30 mg/kg intraperitoneally), Sacubitril/Valsartan (ARNI; 60 mg/kg intraperitoneally) or the same dosage of physiological saline for 1 week. Then each group underwent myocardial infarction induction and received the same treatment for another week. The blood pressure and cardiac function were evaluated prior to sacrifice. We performed histological and molecular evaluation of fibrosis in vivo and in vitro . Results: The blood pressure was comparable between three groups both 1 week prior to and post myocardial infarction. ARNI and ARB restore the decreased ejection fraction (57.3 ± 7.6 vs. 42.9 ± 5.2%, P < 0.05; 54.3 ± 6.9 vs. 42.9 ± 5.2%, P < 0.01, respectively) and fractional shortening (31.6 ± 5.4 vs. 22.1 ± 3.1%, P < 0.05; 29.4 ± 4.5 vs. 22.1 ± 3.1%, P < 0.05, respectively) post myocardial infarction. The infarct size and collagen deposition were also significantly mitigated in ARNI and ARB groups. In addition, ARNI and ARB treatment reduced the expression of cardiac remodeling-related factors, such as Bnp, α-SMA, Vimentin, and Col1a1 (all P < 0.05 vs. MI group). Finally, ARNI and ARB decreased the expression of α-SMA in cardiac fibroblasts treated with Ang II. Conclusion: In conclusion, pretreatment with ARNI maintained cardiac function and reduced myocardial fibrosis in myocardial infarction, probably prior to any anti-hypertensive effect.