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* = Presenting author

P026 Relationship between histological and endoscopic activity and angiogenic and lymphangiogenic factors expression in patients with inflammatory bowel disease

P.M. Linares1, M. Chaparro1, A. Algaba2, I. Guerra2, F. Bermejo2, J.P. Gisbert*1

1Hospital Universitario de La Princesa, IIS-IP and CIBERehd, Gastroenterology Unit, Madrid, Spain, 2Hospital Universitario de Fuenlabrada, Gastroenterology Unit, Madrid, Spain

Background

Aim: To correlate the main angiogenic and lymphangiogenic factors expression in colonic mucosa biopsies with the endoscopic and histological activity in patients with inflammatory bowel disease (IBD)

Methods

Prospective study in patients with IBD that underwent a colonoscopy because of medical criteria. Samples of colonic tissue biopsies for histological analyses were obtained. In patients where activity was observed during colonoscopy, samples from affected and non-affected mucosa were also taken. Endoscopic activity was assessed by endoscopic Mayo subscore for ulcerative colitis (UC) and SES-CD for Crohn's disease (CD). Considering histological findings, patients were classified into four groups: Quiescent IBD, mild, moderate and severe lesion. VEGFA, -C, -D, -R1, -R2, -R3 and PlGF expression Results were graded as follows: (++) over 50% of the tissue cells were stained, (+) below 50%, and (-) completely negative. Ang1, Ang2 and Tie2 were assessed as the average density of five hot spots at a magnification of x40. Protein expression was determined by immunohistochemistry

Results

82 biopsies from 58 patients with IBD (36 UC and 22 CD) were included. 64% of the patients did not have endoscopic activity, 16% had moderate, 14% mild and 6% severe activity. There were significant (p<0.01) differences in the mean count of Ang1 and Ang2 depending on endoscopic activity. Higher expression of Ang1 and Ang2 was found when the endoscopic activity was severe compared to inactive disease. According to histology, 60% of the patients had quiescent IBD, 20% had moderate lesions, 15% mild and 5% severe lesions. Expression of VEGFD (p<0.05), PlGF (p<0.05) and VEGFR3 (p<0.01), and mean count of Ang1 (p<0.05) and Ang2 (p<0.01) were also significantly different depending on the histological activity. These expressions were increased in parallel with the severity of histological lesions excepting for VEGFD, that was decreased with the severity of the activity. Positive correlations (p<0.05) between histological activity and expression of Ang1 (r=0.4), Ang2 (r=0.5), PlGF (r=0.4), VEGFC (r=0.3), and VEGFR3 (r=0.3), and negative for VEGFD (r=-0.3), were demonstrated. On the other hand, positive correlations (p<0.05) between endoscopic activity and expression of Ang1(r=0.4), Ang2(r=0.5), PlGF(r=0.4), and negative for VEGFD(r=-0.3), were found. The best area under the Receiver Operator Characteristic (ROC) curve for the diagnosis of histological activity was 0.73 for Ang1 (cut-off at 39.8: 89% sensitivity and 56% specificity)

Conclusion

The expression of VEGFA, -D, -R3, PlGF, and Ang1 and -2 in mucosal biopsies correlates with the histological activity of IBD. Ang-1 and -2 expressions in mucosal samples are markers of histological and endoscopic activity