Relationship between MVD and meshed-capillaries using magnifying NBI colonoscopy in colorectal precursor lesions.

Background/aims: To prospectively investigate differences in angiogenesis between low-grade dysplasia (LGD) and hyperplastic polyps, as well as the relationship between microvessel density (MVD) as identified by histological analysis and meshed-capillary (MC) vessels visualized using magnifying narrow band imaging (NBI) colonoscopy.

Methodology: Immunohistochemical analysis of MVD was performed using monoclonal antibody against CD31. The number and thickness of vessels were investigated for 45 LGD and 25 hyperplastic polyps. In contrast, NBI colonoscopy was able to classify all lesions into either visualization or nonvisualization of MC vessels.

Results: No significant difference was seen in the number of thin vessels (< or =10 microm) using immunohistochemical MVD analysis between LGDand hyperplasic polyps (p = 0.36). In contrast, the number of intermediate (11-20 microm) and thick vessels (> or =21 microm) differed significantly between LGD and hyperplasic polyps, respectively (p < 0.0001, p < 0.0001). In NBI findings, the presence of MC vessels was found in 98% (44 of 45) of LGD, while MC vessels were absent in 92% (23 of 25) of hyperplasic polyps.

Conclusions: We postulated that the incidence of intermediate and thick vessels (>10 microm) is related to angiogenesis occurring during carcinogenesis of colorectal mucosa. Furthermore, the appearance of visualized MC vessels during magnifying NBI colonoscopy can be used to identify angiogenesis in colorectal LGD and hyperplastic polyps.