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P028. Immunohistochemical expression of Angiopoietin 1 (Ang1) and microvessels density in colon of patients with inflammatory bowel disease (IBD)


P.M. Linares1, M.E. Fernández-Contreras1, A. Algaba2, M. Guijarro Rojas3, F. Bermejo2, M. Chaparro1, J.P. Gisbert1

1Hospital Universitario de la Princesa-IP, Gastroenterology and CIBEREHD, Madrid, Spain; 2Hospital Universitario de Fuenlabrada, Gastroenterology, Fuenlabrada, Spain; 3Hospital Universitario de la Princesa-IP, Pathology, Madrid, Spain



Background: Recent data suggest that Ang1 may play a role in inflammatory angiogenesis, that may be involved in the onset and evolution of IBD. To evaluate the possible differences between IBD and non-IBD, ulcerative colitis (UC) and Crohn's disease (CD), disease activity and histology findings, we have studied the density of microvessels (MV) expressing Ang1 (Ang1+MV) in colonic epithelium of patients with and without IBD.

Methods: Biopsies from patients with and without IBD subjected to colonoscopy by medical criteria were studied by immunohistochemistry. MV were quantified by direct count in four fields at 40X magnification. The mean number of Ang1+MV was studied together with endoscopic and histopathological findings. Endoscopic activity was classified as active and quiescent disease, based on the endoscopic Mayo Subscore (UC) and SES-CD (CD) index. In cases with active disease, biopsies were taken from both endoscopically affected and non-affected mucosa. Following pathologist's criteria, biopsies were classified as normal, affected mucosa, unspecific inflammation, and quiescent.

Results: 67 biopsies from 52 patients with histological diagnosis of IBD (31 UC and 21 EC) and 19 from subjects without IBD were studied. 38.6% cases had active disease. MV count was lower in samples from patients without IBD (Table 1; p < 0.0001), even when comparing only normal mucosa. Patients with UC showed the highest count of Ang1+MV in both cases (Table 2). MV density was also increased in samples with endoscopic activity (52.3±19.5 vs 41.7±15.8; P = 0.02) but it did not correlate with histology.

SD: Standard deviation.
Table 1.
 All samplesNormal histology
 NAng1 (Mean±SD)PNAng1 (Mean±SD)P
UC1948.3±17.4 751.1±12.8
CD4237.3±14.8<0.0001436.6±15.00.001
Non-IBD2531.6±7 1931.6±7
Table 2.
 P value
 All samplesNormal histology
Non-IBD vs UC<0.0001<0.0001
Non-IBD vs CD0.10.3
CD vs UC0.010.1

Conclusions:

  1. UC was associated with an increased density of Ang1+MV, even in samples with normal histology.
  2. Ang1+MV count was higher in mucosa with endoscopic activity.
  3. Our findings might support a role of Ang1 in inflammation induced angiogenesis.