title: Confocal laser endomicroscopy for the morphometric evaluation of microvessels in human colorectal cancer using targeted anti-CD31 antibodies.
abstract: BACKGROUND
  Numerous anti-angiogenic agents are currently developed to limit tumor growth and metastasis. While these drugs offer hope for cancer patients, their transient effect on tumor vasculature is difficult to assess in clinical settings. Confocal laser endomicroscopy (CLE) is a novel endoscopic imaging technology that enables histological examination of the gastrointestinal mucosa. The aim of the present study was to evaluate the feasibility of using CLE to image the vascular network in fresh biopsies of human colorectal tissue. For this purpose we have imaged normal and malignant biopsy tissue samples and compared the vascular network parameters obtained with CLE with established histopathology techniques.
  
  
  METHODS
  Fresh non-fixed biopsy samples of both normal and malignant colorectal mucosa were stained with fluorescently labeled anti-CD31 antibodies and imaged by CLE using a dedicated endomicroscopy system. Corresponding biopsy samples underwent immunohistochemical staining for CD31, assessing the microvessel density (MVD) and vascular areas for comparison with CLE data, which were measured offline using specific software.
  
  
  RESULTS
  The vessels were imaged by CLE in both normal and tumor samples. The average diameter of normal vessels was 8.5±0.9 µm whereas in tumor samples it was 13.5±0.7 µm (p = 0.0049). Vascular density was 188.7±24.9 vessels/mm(2) in the normal tissue vs. 242.4±16.1 vessels/mm(2) in the colorectal cancer samples (p = 0.1201). In the immunohistochemistry samples, the MVD was 211.2±42.9/mm(2) and 351.3±39.6/mm(2) for normal and malignant mucosa, respectively. The vascular area was 2.9±0.5% of total tissue area for the normal mucosa and 8.5±2.1% for primary colorectal cancer tissue.
  
  
  CONCLUSIONS
  Selective imaging of blood vessels with CLE is feasible in normal and tumor colorectal tissue by using fluorescently labeled antibodies targeted against an endothelial marker. The method could be translated into the clinical setting for monitoring of anti-angiogenic therapy.
authors.affiliation: Research Center of Gastroenterology and Hepatology, University of Medicine and Pharmacy of Craiova, Craiova, Romania.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Cârţână
authors.forename: Adrian
authors.initials: A
authors.lastname: Săftoiu
authors.forename: Lucian Gheorghe
authors.initials: LG
authors.lastname: Gruionu
authors.forename: Dan Ionuţ
authors.initials: DI
authors.lastname: Gheonea
authors.forename: Daniel
authors.initials: D
authors.lastname: Pirici
authors.forename: Claudia Valentina
authors.initials: CV
authors.lastname: Georgescu
authors.forename: Adriana
authors.initials: A
authors.lastname: Ciocâlteu
authors.forename: Gabriel
authors.initials: G
authors.lastname: Gruionu
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D001706:Biopsy; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000175:diagnosis*; D004724:Endoscopy; D006801:Humans; D007413:Intestinal Mucosa / Q000098:blood supply / Q000473:pathology; D018613:Microscopy, Confocal; D055806:Microvessels / Q000378:metabolism*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D019408:Platelet Endothelial Cell Adhesion Molecule-1