Is there any relationship between cold-induced vasodilatation and vasomotion?

Area of Science:

• Microcirculation Physiology
• Vascular Biology
• Dermatology

Background:

• Cold-induced vasodilatation (CIV) and vasomotion (VM) are distinct microvascular reactions.
• A direct relationship between CIV and VM has not been previously established.
• Raynaud phenomenon offers a model to study these vascular responses.

Purpose of the Study:

• To investigate the potential relationship between cold-induced vasodilatation (CIV) and vasomotion (VM).
• To analyze fingertip blood flow oscillations during cold exposure in healthy controls and Raynaud phenomenon patients.
• To explore the role of arteriolar-venular anastomoses (AVAs) in these microcirculatory responses.

Main Methods:

• Laser Doppler fluxmetry was used to measure fingertip blood flow in 14 participants (7 controls, 7 Raynaud patients).
• Measurements were taken at room temperature, during cold water immersion (0-6°C), and post-immersion.
• Fourier spectral analysis was applied to the laser Doppler signal to characterize flow oscillations.

Main Results:

• Two distinct patterns of fingertip blood flow oscillations were identified.
• Low-frequency, high-amplitude oscillations (1 cycle/4-6 min) occurred during cold stimulation, resembling CIV.
• High-frequency, low-amplitude oscillations (2-8 cycles/min) persisted throughout, similar to vasomotion (VM).
• These VM-like oscillations were observed in both groups and during both temperature conditions.

Conclusions:

• The findings suggest that cold-induced vasodilatation (CIV) flow oscillations might be an expression of vasomotion (VM) within arteriolar-venular anastomoses (AVAs).
• This provides a potential mechanistic link between CIV and VM in microvascular regulation.
• The study highlights the significant role of AVAs in fingertip blood flow dynamics during thermal stress.