Protective Effect of Esmolol on the Hypertensive Aortic Wall Persists After Withdrawal of Short-Term Treatment

Background: Our research group has previously demonstrated the protective effect of short-term treatment with esmolol on large artery remodeling. However, whether this beneficial effect persists after treatment withdrawal remains unknown. Therefore, the aim of the present study was to investigate whether regression of thoracic aorta remodeling after a short-term esmolol treatment persists following drug withdrawal. Methods: Adult male spontaneously hypertensive rats (SHRs) received either esmolol (300 µg/kg/min) or vehicle (saline solution) by continuous infusion for 48 h. Following treatment, animals were evaluated either immediately (SHR-E 48 h group) or after withdrawal periods of 7 days (SHR-E 7 d group) or 1 month (SHR-E 1 m group). Hemodynamic parameters, thoracic aorta geometry, extracellular matrix composition (elastin and collagen), and the passive mechanical response of the arterial wall (β parameter) were assessed in all animals. Results: Forty-eight hours of esmolol treatment significantly reduced blood pressure and attenuated thoracic aortic wall thickness, external diameter, cross-sectional area, collagen content and elastic fiber density. Additionally, passive mechanical testing showed a significant reduction in the β parameter, indicating improved arterial compliance after treatment. Remarkably, these structural and mechanical benefits persisted for up to one month after withdrawal, despite the return of blood pressure to hypertensive levels. Conclusions: Protective effect of esmolol on aortic remodeling is persistent after treatment withdrawal in SHRs, perhaps independent of blood pressure.