Changes in vascular responsiveness during a hyperglycemia challenge measured by near-infrared spectroscopy vascular occlusion test

Background Postprandial hyperglycemia is associated with impaired vascular responsiveness. Recent studies have established the use of a near-infrared spectroscopy (NIRS)-derived approach, combined with a vascular occlusion test (VOT), to examine vascular responsiveness within the microvasculature in normoglycemia. The aim of this study was to examine whether this NIRS-VOT technique could detect differences in vascular responsiveness following a hyperglycemic challenge. Methods and results Fourteen young healthy individuals participated in the study. Participants underwent five vascular occlusion tests (pre, 30, 60, 90 and 120 min after glucose ingestion). Vascular responsiveness was determined by the slope 2 of oxygen saturation (Slope 2 StO₂) and the area under the curve of oxygen saturation (StO_2AUC) signal. All individuals had a significant increase in blood glucose concentration after 30 min (p < 0.001), 60 min (p < 0.001) and 90 min (p < 0.01) after glucose ingestion. The Slope 2 StO₂ increased at 90 min (p < 0.01) after glucose ingestion. Conversely, The StO_2AUC was significantly decreased 90 min following the glucose challenge (p < 0.01). A negative correlation was observed between average StO_2AUC and average Slope 2 StO₂ (r = − 0.995; p < 0.05). Conclusion This study showed that the NIRS-VOT technique is capable of detecting differential changes in vascular responsiveness to a hyperglycemic challenge, as indicated by a steeper Slope 2 StO₂ and decreased StO_2AUC following 90 min of an oral glucose challenge.