Endothelial dysfunction in middle-aged and older men with low testosterone is associated with elevated circulating...

Area of Science:

• Cardiovascular Biology
• Endocrinology
• Vascular Aging

Background:

• Low testosterone in aging men is associated with accelerated vascular aging and endothelial dysfunction.
• The precise mechanisms linking low testosterone to endothelial dysfunction remain unclear.
• Endothelin-1 (ET-1) is a potent vasoconstrictor implicated in vascular disease.

Purpose of the Study:

• To investigate the association between plasma endothelin-1 (ET-1) levels and brachial artery flow-mediated dilation (FMD) in middle-aged and older men with low testosterone.
• To compare endothelial function and ET-1 levels across different testosterone status groups.

Main Methods:

• Plasma ET-1 levels and brachial artery FMD were measured in three groups: young men, middle-aged/older men with normal testosterone, and middle-aged/older men with low testosterone.
• Endothelial cell ET-1 expression was assessed via endovascular biopsy in a subset of participants.
• Statistical analyses were performed to determine associations between variables.

Main Results:

• Middle-aged/older men with low testosterone exhibited significantly reduced FMD compared to both young men and age-matched men with normal testosterone.
• Plasma ET-1 levels were significantly higher in men with low testosterone compared to the other two groups.
• A significant inverse correlation was found between plasma ET-1 levels and FMD, suggesting ET-1 contributes to endothelial dysfunction.

Conclusions:

• Accelerated age-associated endothelial dysfunction in men with low testosterone is associated with elevated circulating ET-1.
• Higher plasma ET-1 is a potential mechanism contributing to reduced vascular endothelial function in this population.
• The exact source of increased plasma ET-1 in men with low testosterone requires further investigation.