BNP as a Marker and Mediator of Myocardial Wall Stress

Mechanism of BNP Synthesis and Release

BNP is released directly from ventricular myocardium when mechanical stress increases wall tension due to volume or pressure overload【1】.
Ventricular myocytes synthesize and secrete BNP in response to end‑diastolic wall stress caused by elevated ventricular volume or pressure【1】.
BNP production requires de novo gene transcription; the BNP gene is rapidly up‑regulated by stress signals rather than being stored in pre‑formed granules【2】【3】.
In heart failure and other cardiac pathologies, BNP synthesis shifts from the atria to the ventricles, making the ventricles the predominant source【2】【4】.
The precursor pre‑proBNP is cleaved to proBNP and then proteolytically processed by furin and corin into NT‑proBNP and the biologically active BNP peptide【1】.

Increased ventricular filling pressures raise end‑diastolic wall stress, prompting BNP release【1】.
Myocardial ischemia from supply‑demand mismatch, especially in vulnerable subendocardial regions, stimulates BNP secretion【1】.
Fluid retention leading to volume overload activates BNP production【2】.
Pressure overload conditions such as aortic stenosis or systemic hypertension trigger BNP release【2】【5】.
Ventricular myocytes re‑express fetal genes—including BNP—when exposed to chronic pressure or volume overload【3】【4】.

Elevated BNP concentrations are observed in all edematous states with salt and fluid overload and in renal failure, not exclusively in heart failure【2】【5】.
Because BNP rises proportionally to myocardial wall stress, it serves as a quantitative marker of cardiac stress rather than a disease‑specific biomarker【2】.

BNP promotes natriuresis and diuresis, helping to reduce intravascular volume overload【2】【3】.
BNP induces vasodilation, thereby decreasing afterload【2】.
BNP antagonizes the renin‑angiotensin‑aldosterone system and the sympathetic nervous system, contributing to neurohormonal modulation【2】【4】.
BNP inhibits cardiac and vascular remodeling, providing cytoprotective effects that limit adverse structural changes【3】【4】.