Circulating and cellular markers of endothelial dysfunction with aging in rats

Area of Science:

• Cardiovascular Physiology
• Aging Research
• Endothelial Biology

Background:

• Endothelial dysfunction is a hallmark of aging, contributing to cardiovascular disease.
• Key enzymes like ACE and NOS play crucial roles in regulating vascular tone and endothelial health.
• Understanding age-related changes in these markers is vital for developing preventative strategies.

Purpose of the Study:

• To investigate the influence of aging on endothelial functional markers in rats.
• To examine the age-dependent changes in Angiotensin I converting enzyme (ACE) and nitric oxide synthase (NOS) expressions in the lung and aorta.
• To assess the correlation between these molecular changes and circulating endothelial cell levels.

Main Methods:

• Examined ACE activity and NOS mRNA expression in lung and aorta of rats aged 10, 20, and 30 months.
• Measured circulating endothelial cells.
• Assessed guanosine 3',5'-cyclic monophosphate (cGMP) concentrations in the aorta.

Main Results:

• ACE activity decreased in plasma and lungs but increased in the aorta with age.
• Constitutive endothelial NOS (eNOS) mRNA reduced in the aorta, while inducible NOS (iNOS) mRNA decreased in the aorta and increased in the lung of older rats.
• Increased circulating endothelial cells in aged rats suggest elevated endothelial turnover.

Conclusions:

• Aging significantly modifies endothelial markers involved in vasomotor tone regulation.
• Age-dependent impairment of endothelial function is evident, potentially increasing the risk of arterial wall pathologies.
• These findings highlight the complex impact of aging on the vasculature.