Assessment of blood flow in the small intestine by laser Doppler flowmetry: Comparison of healthy small intestine and small intestine in Crohn's disease

Abstract

Blood flow and blood distribution were investigated in 40 patients with normal small intestine and the relation between blood flow and the morphological features of Crohn's disease was examined in 11 patients with Crohn's disease by laser Doppler flowmetry from the serosal side during surgery. In normal small intestine, blood flow was measured at six points: upper, middle, and lower small intestine, each of the mesenteric borders, and the antimesenteric surface. In Crohn's disease, macroscopically normal tissue and affected lesions were observed in detail by intraoperative endoscopy after blood flow measurement. The blood flow values in the normal small intestine gradually decreased from the upper to the lower small intestine. As the level of inflammation progressed in Crohn's disease the blood flow values gradually decreased; the exudative stage of Crohn's disease (aphthoid ulcer) showed blood flow values that were slightly below those in macroscopically normal tissue. These results are the first to demonstrate decreased blood flow in affected lesions in Crohn's disease and changes in blood flow according to the degree of inflammation in vivo.

On the role of ischemia in the pathogenesis of IBD

“…Lunderquist and Knutsson 20 showed that in chronic IBD with luminal narrowing, the mesenteric arterial caliber decreases from its initial dilated state to one characterized by irregularity, tortuosity, right angle bifurcations, and a reduced arterial caliber, suggesting that decreased blood flow and diminished perfusion are features of the chronically inflamed bowel. In a study comparing blood flow measurements of endoscopically normal and inflamed small intestine in patients with CD, Tateishi et al 26 found that as the inflammation worsened, blood flow gradually decreased. That poor perfusion and microvascular ischemia vary with disease duration and activity was further substantiated using isotope washout techniques to examine regional intestinal blood flow and its intramural distribution at different stages of disease.…”

“…The paradox remains, however, that an increased vascularity does not necessarily imply adequate and appropriate perfusion, as evidenced by ultrasound studies that have shown decreased perfusion in the segments of chronically inflamed IBD intestine. 21,26,27 The knowledge that such neovasculature frequently is dysfunctional has provided opportunities to develop novel therapeutic approaches for IBD. Increased understanding of the vascular biology of IBD has now allowed researchers to begin to exploit the numerous perturbations involving the microvasculature; for example, it has been shown that there is an increased expression of cellular adhesion molecules and selective recruitment of leukocytes binding to a4 integrin in the chronically inflamed intestine.…”

Colon Ischemia: Recent Insights and Advances

“…Interestingly, decreased blood flow and diminished perfusion are features of chronically inflamed bowel, as shown by studies in patients with inflammatory bowel disease (IBD) [6], and as inflammation worsens, blood flow decreases [7]. Also noteworthy is the relationship between small vessel occlusion and subsequent granuloma formation [8], again raising the question of whether IBD has an ischemic component [9•].…”

Effects of n–3 Polyunsaturated Fatty Acids and Vitamin E on Colonic Mucosal Leukotriene Generation, Lipid Peroxidation, and Microcirculation in Rats with Experimental Colitis

“…Recent studies using laser Doppler flowmetry during endoscopy or surgery demonstrated that impaired intestinal microcirculation may play a pathogenic role and may be related to the degree of inflammation in patients with IBD [7, 8]. Since LTs and LPO are potent mediators of microcirculatory change [9, 10], their overproduction in the mucosa may contribute to the impaired mucosal blood flow and could lead to mucosal damage.…”

“…Impaired mucosal microcirculation of the intestine has been reported in IBD patients [7, 8]. Decreased mucosal blood flow is thought to be induced by many factors, including LTs and LPO, and it can cause tissue damage both directly and through the overproduction of various chemical mediators [9, 10].…”