[Microcirculation of the small intestines in local and generalized circulatory disorders]

Microcirculatory disturbances are known to affect the integrity of the gastrointestinal barrier. In our experiments, we aimed at characterizing the intramural microcirculatory reactions in response to various circulatory disorders using intravital microscopy with orthogonal spectral imaging technique. For the analysis and comparison of the microcirculatory reactions in the intestinal ileal mucosa, longitudinal muscle and Peyer's patches, a novel mathematical formula was established.

The microcirculatory consequences of mesenteric artery occlusion, endotoxemia, hemorrhagic shock and nitric oxide synthesis inhibition were characterized.

During reperfusion, red blood cell velocity (RBCV) decreased by approx. 20% in all layers which persisted by end of the observation. In response to endotoxin, microcirculation of the muscle was more affected than that of the mucosa. In the hypovolemic phase of hemorrhagic shock and the late phase of resuscitation, a characteristic oscillatory flow pattern appeared in the villi and the weighed arithmetic average of RBCV decreased by 50%. NO synthesis inhibition caused an approx. 40% fall in RBCV in all layers and a spatial heterogeneity in the villi.

Systemic circulatory disorders are characterized by a non-uniform microcirculatory failure and a redistribution of blood flow between the different layers favouring the mucosa. Using the suggested mathematical formula, the microcirculatory alterations can be characterized and compared.