What turns on the endothelins?

Area of Science:

• Cardiovascular Physiology
• Endocrinology
• Immunology

Background:

• Elevated endothelin-1 (ET-1) production occurs in pathologies like ischemia-reperfusion, vasculitis, heart failure, and septic shock.
• These conditions correlate with increased cytokine production, including tumor necrosis factor-alpha and interleukin-2.

Purpose of the Study:

• To investigate the link between cytokine-induced endothelial activation and endothelin-1 (ET-1) system upregulation.
• To determine the role of ET-1 in cytokine-mediated cardiovascular effects in pathological states.

Main Methods:

• Administration of tumor necrosis factor-alpha and interleukin-2 to rats to measure circulating ET-1 levels.
• Assessment of ET-1-dependent coronary vasoconstriction and coronary perfusion pressure in rats with adjuvant polyarthritis.
• Evaluation of endothelin receptor antagonist effects on coronary perfusion pressure in disease models.

Main Results:

• Cytokine administration in rats led to rapid increases in circulating ET-1 levels and pronounced ET-1-dependent coronary vasoconstriction.
• Rats with adjuvant polyarthritis exhibited significant increases in coronary perfusion pressure, which were abolished by endothelin receptor antagonists.
• Coronary perfusion pressure in rats served as a sensitive bioassay for ET-1 activity due to its potent vasoconstrictive effects.

Conclusions:

• The endothelin-1 (ET-1) system is typically latent but can be rapidly upregulated by cytokines during endothelial activation in disease states.
• Cytokine-induced ET-1 production plays a significant role in cardiovascular changes observed in various pathological conditions.
• Targeting the ET-1 pathway may offer therapeutic potential in diseases associated with inflammation and vasoconstriction.