Imaging of the Intestinal Microcirculation during Acute and Chronic Inflammation

SIMPLE SUMMARY: Microcirculation refers to the smallest blood vessels within the body. During inflammation, changes can occur within these vessels which can further disease processes. Blood vessels in the gut are particularly vulnerable. Videomicroscopy devices are important for examining these changes. In animal experiments, intravital microscopy is the gold standard for evaluation. This technique allows for the visualization of these vessels within living animals. The changes that occur vary depending on the length of time the inflammation has been occurring for. Examples of these changes include changes in blood flow, vessel density and immune cell activation. This review discusses these changes in the context of various inflammatory conditions including infections of the intestine and pancreas, and non-infectious conditions of the bowel. ABSTRACT: Because of its unique microvascular anatomy, the intestine is particularly vulnerable to microcirculatory disturbances. During inflammation, pathological changes in blood flow, vessel integrity and capillary density result in impaired tissue oxygenation. In severe cases, these changes can progress to multiorgan failure and possibly death. Microcirculation may be evaluated in superficial tissues in patients using video microscopy devices, but these techniques do not allow the assessment of intestinal microcirculation. The gold standard for the experimental evaluation of intestinal microcirculation is intravital microscopy, a technique that allows for the in vivo examination of many pathophysiological processes including leukocyte-endothelial interactions and capillary blood flow. This review provides an overview of changes in the intestinal microcirculation in various acute and chronic inflammatory conditions. Acute conditions discussed include local infections, severe acute pancreatitis, necrotizing enterocolitis and sepsis. Inflammatory bowel disease and irritable bowel syndrome are included as examples of chronic conditions of the intestine.