title: Human in vivo cellular response to a cross-linked acellular collagen implant.
abstract: BACKGROUND
  Hernia surgery, in particular parastomal hernia mesh repair and new techniques for hernia prevention, require novel biomaterials that avoid fibrosis and potential bowel erosion, while retaining adequate strength for their intended purpose. The aim was to evaluate the human host response to an acellular porcine-derived cross-linked collagen implant.
  
  
  METHODS
  In a prospective pilot study on prevention of parastomal herniation, 15 patients undergoing loop stoma formation had an implant placed within the anterior abdominal wall. Histopathology and immunohistochemistry were performed to analyse the implant qualitatively and, where appropriate, quantitatively for biocompatibility, degradation, cellular infiltration, neo-extracellular matrix (ECM) formation and neovascularization.
  
  
  RESULTS
  At a median of 7 (range 1-8) months, 12 of 15 patients had stoma reversal and 11 implant biopsies were obtained. In biopsies from ten of the 11 patients all responses were limited to the periphery of the implant and native pores. There was a minimal inflammatory response and minimal degradation of the implant. Fibroblastic and neovascular infiltration were noted, as was matrix metalloproteinase 1 activity with organized deposition of host collagen, fibronectin and laminin.
  
  
  CONCLUSIONS
  The collagen implant demonstrated excellent biocompatibility and resistance to degradation in most patients. However, fibrovascular in-growth and ECM deposition were limited. This implant has excellent potential for soft tissue reinforcement.
authors.affiliation: Centre for Academic Surgery, Institute of Cellular and Molecular Science, The Royal London Hospital, Barts and The London NHS Trust, Queen Mary School of Medicine and Dentistry, University of London, London, UK. t.hammond@qmul.ac.uk
authors.forename: T M
authors.initials: TM
authors.lastname: Hammond
authors.forename: J
authors.initials: J
authors.lastname: Chin-Aleong
authors.forename: H
authors.initials: H
authors.lastname: Navsaria
authors.forename: N S
authors.initials: NS
authors.lastname: Williams
mesh_terms: D001706:Biopsy; D003094:Collagen / Q000627:therapeutic use*; D006547:Hernia / Q000517:prevention & control*; D006789:Host vs Graft Reaction; D006801:Humans; D007077:Ileal Diseases / Q000517:prevention & control*; D007081:Ileostomy / Q000379:methods*; D007082:Ileum / Q000473:pathology*; D007150:Immunohistochemistry; D010865:Pilot Projects; D011446:Prospective Studies; D019919:Prosthesis Implantation / Q000379:methods; D012086:Reoperation / Q000706:statistics & numerical data; D054047:Surgical Stomas / Q000473:pathology*; D013718:Tensile Strength
chemical_list: C422414:Permacol; D003094:Collagen