title: The peritoneal cavity is a distinct compartment of angiogenic molecular mediators.
abstract: OBJECTIVE
  This study was designed to analyze porcine plasma and peritoneal fluid for concentration differences of angiogenic molecular mediators and to determine local peritoneal sites of production of these molecules.
  
  
  BACKGROUND
  The peritoneum is now recognized as a dynamic cellular membrane with important functions, including antigen presentation; transport and movement of fluid, solutes, and particulate matter across serosal cavities; and secretion of glycosaminoglycans, extracellular matrix proteins, proinflammatory cytokines, and growth factors. The mechanisms of the peritoneal response to injury and the factors that determine the outcome of the reactive or reparative processes of the peritoneum remain poorly defined.
  
  
  METHODS
  Domestic swine (n = 12) underwent percutaneous diagnostic peritoneal lavage to obtain preincision peritoneal fluid for biochemical analysis. Open biopsy samples of parietal peritoneum and omentum were obtained for immunochemical and molecular analysis. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) levels were quantitated by enzyme-linked immunosorbent assay, and nitrite/nitrate (NOx) measured by nonenzymatic assay. Sections of formalin-fixed tissue were stained for immunoreactivity to VEGF, bFGF, and nitric oxide synthase (NOS). Frozen homogenized peritoneum and omentum were prepared for isolation of protein and RNA. An endothelial growth assay was created using human umbilical vein endothelial cells cultured with peritoneal fluid with or without anti-VEGF or anti-bFGF antibodies.
  
  
  RESULTS
  The mean plasma concentrations of VEGF, bFGF, and NOx were 20 +/- 5 pg/mL, 35 +/- 9 pg/mL, and 4.5 +/- 1.3 microm, compared with mean peritoneal fluid concentrations of 395 +/- 75 pg/mL, 486 +/- 72 pg/mL, and 35.0 +/- 8.8 mum respectively (P < 0.05 for each molecule). Immunochemistry demonstrated VEGF, bFGF, and NOS protein in mesothelium, submesothelium, and omentum. The use of Western blotting and reverse transcription polymerase chain reaction confirmed peritoneal and omental presence of VEGF and NOS-2. The use of endothelial bioassay documented peritoneal fluid angiogenic activity, which was inhibited by addition of neutralizing antibody to VEGF or bFGF.
  
  
  CONCLUSIONS
  Peritoneal compartmentalization of angiogenic mediators important in wound healing, inflammation, and tumor growth suggests that the plasma concentrations of these mediators do not reflect their tissue concentrations or local biological activity.
authors.affiliation: Department of Surgery, University of New Mexico HSC, Albuquerque, New Mexico 87131-0001, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Nachtsheim
authors.forename: Ben
authors.initials: B
authors.lastname: Dudley
authors.forename: Paul L
authors.initials: PL
authors.lastname: McNeil
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Howdieshell
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000737:chemistry*; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000032:analysis* / Q000097:blood; D007150:Immunohistochemistry; D009569:Nitric Oxide / Q000032:analysis* / Q000097:blood; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000097:blood; D013552:Swine; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis* / Q000097:blood
chemical_list: D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase