Altered skin flowmotion in hypertensive humans.

Area of Science:

• Cardiovascular Physiology
• Microvascular Function
• Hypertension Research

Background:

• Essential hypertension is linked to impaired nitric oxide (NO)-dependent vasodilation in the skin.
• Understanding microvascular control alterations in hypertension is crucial for cardiovascular health.
• Spectral analysis of laser-Doppler flowmetry offers insights into vasoreactivity.

Purpose of the Study:

• To characterize skin flowmotion using spectral analysis during vasodilation in hypertensive and normotensive individuals.
• To investigate the role of nitric oxide synthase (NOS) inhibition on microvascular control.
• To compare spectral characteristics between hypertensive and normotensive subjects.

Main Methods:

• Laser-Doppler flowmetry was used to record skin blood flow during local heating in 18 hypertensive and 18 normotensive participants.
• Pharmacological inhibition of NOS using N(G)-nitro-l-arginine methyl ester (l-NAME) via microdialysis assessed NO-dependent vasodilation.
• Fast Fourier Transformation (FFT) analyzed power spectral densities (PSDs) across different frequency intervals.

Main Results:

• Local heating increased total PSD in all frequency intervals for both groups.
• Hypertensives exhibited lower total and neurogenic PSDs compared to normotensives, with altered normalized contributions.
• NOS inhibition reduced total PSD in both groups, with hypertensives showing significantly lower endothelial, neurogenic, and total PSDs.

Conclusions:

• Essential hypertension is associated with altered neurogenic and NOS-dependent control of skin microvascular function.
• Spectral analysis is a valuable non-invasive tool for assessing vasoreactivity and microvascular dysfunction.
• Findings suggest impaired endothelial and neurogenic contributions to skin blood flow regulation in hypertension.