PB1349 - Effect of polarized red laser photobiomodulation therapy on endothelial functionof healthy human brachial artery using diagnostic ultrasound- based Flow- Mediated Dilation (FMD) protocol

Background: The pathological complications of atherosclerosis, namely infarction and stroke, remain the leading cause of mortality in the world. Preceding atherosclerosis is endothelial dysfunction. There is therefore, interest in the application of non-invasive clinical tools to enhance and assess endothelial function.

Aims: We used an ultrasound-based computerized image analysis method in this work to examine the effect of polarized red laser (632nm, 250 J/cm2) irradiation on the endothelial function in healthy volunteers.

Methods: The Flow-Mediated Dilation (FMD) test is the standard tool used to assess endothelial function. FMD is typically expressed as the percentage increase in the artery diameter above baseline. A pneumatic tourniquet placed around the healthy subjects’ forearm, just below the elbow and inflated to a super systolic blood pressure for 5 minutes for FMD examination. In this study we used a new computerized analysis method for measurement of instantaneous changes in far and near arterial walls in sequential ultrasound images. Approximately 70 sequential ultrasound images spanning three cardiac cycles were analyzed from each FMD examination to detect instantaneous changes in the far and near walls and lumen maximum, minimum, and mean diameters.

Results: FMD assessment and morphometric analysis of the mean value for arterial diameter in the treatment group showed a significant increase compared with the other groups (P < 0.05).

Conclusion(s): Red laser photobiomodulation therapy, can cause to enhance the endothelial nitric oxide synthase, resulting in an increase in the arterial diameter. Furthermore, we concluded that our new ultrasound image processing software is realable to accurate and repeated evaluation of FMD.