Evaluation of Morphology and Microcirculation of the Pancreas by ex vivo and in vivo Reflectance Confocal Microscopy

Pancreatic proteases in serum induce leukocyte-endothelial adhesion and pancreatic microcirculatory failure

“…In addition to demonstrating a direct promoting effect of pancreatic proteases on the interactions of leukocytes and endothelium through fluorescence microscopy in vivo, we evaluated changes in the pancreatic microcirculation by in vivo confocal microscopy. This novel technique has previously been evaluated by our group for real-time evaluation of unimpaired microcirculation in the healthy pancreas [13]. The advantage of real-time confocal microscopy is that it enables the assessment of tissue perfusion of the pancreas without the use of potentially toxic dyes required for conventional invivo fluorescence microscopy [64,65].…”

“…The operating parameters and experimental setup have been specified in detail [13,20]. Briefly, for real-time confocal microscopy, laparotomy was performed after anesthesia 9 h after induction of acute pancreatitis, and the pancreatic head was released from the surrounding tissue by carefully dissecting the tissue connections to the transverse mesocolon and the ligament of Treitz.…”

“…The pancreatic microcirculation in each experiment was quantitated by determination of the functional capillary density (FCD), defined as the length of erythrocyte-perfused capillaries (mm) per observation area (mm 2 ) [13,20]. A grid (squared-type/square size 50 Ìm) was superimposed on the video screen and intersections of erythrocyte-perfused capillaries with this grid system were counted.…”

“…In this study we provide evidence that both elastase and trypsin in serum alone trigger this interaction and that this process in vitro is independent of proinflammatory cytokines or oxygen radicals. Employing real-time reflectance confocal microscopy (CM) [13] and intravital fluorescence microscopy in vivo, we demonstrate that the activated leukocyte-endothelial interaction following infusion of these proteases leads directly to reduced microcirculatory perfusion, which in turn can be prevented in part by inhibition of proteases.…”

Signal transduction, calcium and acute pancreatitis

“…In this regard, extension of these studies to other in vitro and in vivo models of acute pancreatitis will be useful [68,69]. The calcium-signalling abnormalities themselves require further characterisation, to distinguish principal features that are disease initiators, including amplitude, timing and subcellular location.…”