Intramyocardial BNP gene delivery improves cardiac function through distinct context-dependent mechanisms

Area of Science:

• Cardiology
• Molecular Biology
• Genetics

Background:

• B-type natriuretic peptide (BNP) is an endogenous peptide with protective actions in cardiovascular diseases.
• BNP exhibits natriuretic, diuretic, blood pressure-lowering, and antifibrotic effects.
• Investigating BNP's role in left ventricular (LV) remodeling is crucial for understanding cardiorenal protection.

Purpose of the Study:

• To examine the functional and structural effects of BNP gene transfer on LV remodeling.
• To assess BNP's impact on cardiac function and structure in models of postinfarction and hypertension.

Main Methods:

• Adenovirus-mediated gene delivery was used to overexpress human BNP in rat hearts.
• Studies were conducted in normal hearts, post-infarction hearts, and in a model of angiotensin II-induced hypertension.
• Cardiac function (fractional shortening, ejection fraction), fibrosis, capillary density, and molecular markers were analyzed.

Main Results:

• In healthy hearts, BNP gene delivery reduced myocardial fibrosis and increased capillary density.
• Post-infarction, BNP overexpression improved LV fractional shortening and ejection fraction, normalizing key molecular markers.
• In hypertension, BNP improved cardiac function and reduced fibrosis but did not affect angiogenesis or specific molecular markers.

Conclusions:

• Local intramyocardial BNP gene delivery enhances cardiac function and mitigates adverse remodeling post-infarction and in hypertension.
• Myocardial BNP demonstrates context-dependent, beneficial effects on cardiac function.
• BNP acts locally as a critical regulator of angiogenesis and fibrosis in response to mechanical load.