Evaluation of a combined laser Doppler flowmetry and iontophoresis technique for the assessment of equine cutaneous microvascular function.

The research tested a combined laser Doppler flowmetry and iontophoresis (LDFI) technique, typically applied in human medical procedures, as a non-invasive method for analyzing horse microvascular function relating to diseases like laminitis.

Background and Objectives

• The study aimed to test the efficacy and reliability of the Laser Doppler flowmetry and iontophoresis (LDFI) method in assessing microvascular function in horses.
• This method is normally employed in human microvascular function examinations, and the researchers wanted to assess its potential for research and clinical usage in equine microvascular function analysis.
• The study was focused on facilitating the understanding and study of diseases such as laminitis in horses.

Methods

• Baseline and vasoactive agonist (acetylcholine and nitroprusside)-induced microvascular flux was quantified in six clinically normal horses.
• The measurements were taken at two different sites: the dorsal pastern adjacent to the coronary band and the gluteal region.
• This experiment was carried out 5 or 6 times under standardized conditions to monitor the results for reliability and consistency.

Results

• The findings showed that both acetylcholine and nitroprusside notably increased microvascular flux.
• It was noted that skin pigmentation significantly attenuated the baseline flux but did not affect the magnitude of the agonist-triggered vasodilatory response.
• This indicated that the skin colour of the horses had an impact on the LDFI readings.

Conclusion

• Despite being easy to execute, the LDFI method’s usefulness in studying and assessing the equine cutaneous microcirculation was found to be limited, primarily because of its questionable reliability.
• The technique showed substantial variability in baseline and agonist-induced microvascular flux among individual horses and within the same horse over different trials, demonstrating its poor consistency and reliability.