Aldosterone mediates cardiac fibrosis in the setting of hypertension

Area of Science:

• Cardiovascular Science
• Renal Physiology
• Molecular Cardiology

Background:

• Arterial hypertension induces cardiac remodeling, characterized by cardiomyocyte hypertrophy, inflammation, fibrosis, and rarefaction.
• Hormonal factors, particularly Angiotensin II and aldosterone, play a significant role in pathological cardiac remodeling.
• Cardiac fibrosis involves a complex interplay of pro-fibrotic (e.g., TGF-ß, galectin-3) and anti-fibrotic (e.g., BNP, ANP) factors.

Purpose of the Study:

• To review the specific impact of inappropriate aldosterone stimulation on the development of cardiac fibrosis.
• To highlight the role of mineralocorticoid receptor activation in macrophages in mediating aldosterone-induced cardiac fibrosis.

Main Methods:

• Review of experimental models, including transgenic mice with altered renin or aldosterone-synthase expression.
• Analysis of studies involving cell-specific deletion of the mineralocorticoid receptor in macrophages.
• Synthesis of findings on the balance of fibrotic and anti-fibrotic factors in the hypertensive heart.

Main Results:

• Aldosterone, in collaboration with Angiotensin II, promotes cardiomyocyte hypertrophy, inflammation, and fibrosis.
• Cardiac fibrosis is regulated by a balance between pro-fibrotic and anti-fibrotic signaling pathways.
• Activation of the mineralocorticoid receptor within macrophages is a critical mediator of cardiac fibrosis.

Conclusions:

• Excessive aldosterone stimulation is a key driver of cardiac fibrosis in hypertension.
• Targeting macrophage mineralocorticoid receptor activation may represent a therapeutic strategy for hypertensive cardiac fibrosis.