Ventricular natriuretic peptide

Ventricular Natriuretic Peptide (VNP), also known as Brain Natriuretic Peptide (BNP) when referring to its cardiac origin, is a peptide hormone primarily involved in the regulation of blood pressure and fluid balance in the body. It is secreted by the ventricles of the heart in response to excessive stretching of heart muscle cells (cardiomyocytes). The release of VNP is a crucial component of the body's response to heart failure and conditions leading to increased blood volume and pressure.

Function

Ventricular Natriuretic Peptide plays a significant role in the body's cardiovascular homeostasis by inducing natriuresis (the excretion of sodium through urine), thereby reducing blood volume and pressure. It achieves this by inhibiting the functions of the renin-angiotensin-aldosterone system (RAAS), reducing the absorption of sodium in the kidneys, and dilating the blood vessels. Additionally, VNP inhibits the secretion of aldosterone from the adrenal cortex, further promoting sodium and water excretion.

Clinical Significance

The measurement of BNP or its precursor, N-terminal pro b-type natriuretic peptide (NT-proBNP), is widely used in the diagnosis and management of heart failure. Elevated levels of these peptides are indicative of increased ventricular pressure and can be used to assess the severity of the condition. Furthermore, VNP has therapeutic implications; synthetic analogs such as Nesiritide are used in the treatment of acute decompensated heart failure to rapidly decrease cardiac filling pressures and improve symptoms.

Pathophysiology

In conditions such as heart failure, where the heart's ability to pump blood efficiently is compromised, the ventricles respond by secreting increased amounts of VNP. This compensatory mechanism aims to reduce the workload on the heart by decreasing blood volume and pressure. However, in chronic heart failure, the continuous high levels of VNP can lead to detrimental effects, including electrolyte imbalances and reduced responsiveness to natriuretic peptides, a condition known as natriuretic peptide system "resistance."

Research Directions

Current research is focused on exploring the potential of VNP as a biomarker for early detection of heart failure and its utility in predicting the prognosis of patients with cardiovascular diseases. Additionally, studies are investigating the development of new therapeutic agents that can enhance the natriuretic peptide system or mimic the actions of VNP to treat heart failure more effectively.

See Also

• Atrial Natriuretic Peptide
• C-type Natriuretic Peptide
• Renin-Angiotensin System
• Heart Failure