Quantitative Analyse der Mikrozirkulation von Wunden mit OPS imaging Quantitative analysis of the microcirculation of wounds using OPS imaging

Introduction: Orthogonal polarization spectral (OPS) imaging, implemented into the CYTOSCAN AIR, is a new, recently introduced technique to produce high contrast images of the microcirculation without the necessity for fluorescent dyes. The aim of the study was to validate OPS imaging against intravital fluorescence microscopy (IFM) for micro­ vascular measurements in normal skin and during wound healing. Material and Methods: Experiments were carried out on the ears of hairless mice (n = 8). A circular wound was created according to Bondar and coworkers. The diameter of arterioles and venules, red blood cell velocity in arterioles and venules, as well as the functional capillary density were assessed under normal conditions using OPS imaging and IFM. After subsequent creation of the wound these observations were repeated at the identical microvascular re­ gions (days 4,7,10,15). Images were videotaped and CapImage was used for offline com­ puter assisted analysis. Results: Using OPS imaging the micorcirculation of wounded skin on ears of hairless mice could successfully be observed. The regression analyses against standard IFM revealed significant correlation for measurements of all microcirculatory parameters investigated. Further statistical analyses using the method of Bland and Alt­ man showed a very good agreement of the data obtained with both techniques. However, for diameter as well as for FCD measurements OPS imaging yielded lower absolute values as compared to IFM. Conclusions: We were able to validate OPS imaging against IFM for the measurement of microvascular parameters in an animal model of skin wound heal­ ing. Such a device should now help to study the role of the microcirculation in physiology and pathophysiology during wound healing in patients without the need for a fluoro­ chrome or other invasive approaches. First clinical investigations are promising.