In vivo reflectance-mode confocal microscopy provides insights in human skin microcirculation and histomorphology

PURPOSE Various approaches are used to study microcirculation, however, no modality evaluates microcirculation and histomorphology on cellular levels. We hypothesized that reflectance-mode confocal microscopy (RCM) enables simultaneous evaluation in vivo of both microcirculation and histomorphology. PRINCIPALS The forearm of 20 volunteers was exposed to either local heat stress (HS-group), or to local cold stress (CS-group). RCM was performed prior and after temperature stress to evaluate quantitative blood-cell flow, capillary loop diameter, granular cell size, and basal layer thickness. RESULTS In the HS-group, we observed significant increase in capillary loop diameter and increased blood-cell flow after heat stress. In the CS-group, significant decreases of capillary loop diameter and in blood-cell flow were determined following cold stress. Granular cell size and basal layer thickness differed insignificantly prior and after local temperature stress. CONCLUSIONS RCM provides real-time and in vivo high resolution imaging of temperature-dependent changes in the human skin microcirculation and histomorphology on cellular levels.