title: In-vivo and in-vitro histological evaluation of two commercially available acellular dermal matrices.
abstract: OBJECTIVE
  Post-herniation abdominal wall repair can be performed with synthetic or biologic meshes. Synthetics have been associated with complications, so biologics are promising alternatives. The methods used to decellularize biological matrices may affect the extracellular components. This study evaluated the post-implantation biological response of two allogenic acellular dermal matrices (ADMs) in a hernia model.
  
  
  METHODS
  Testing was conducted with two ADMs from different manufacturers: RTI Biologics (ADM-R) and LifeCell (ADM-L). Samples were evaluated for collagen IV, glycosaminoglycans (GAGs), and elastin before implantation. Samples were also used to repair bilateral full-thickness defects in rat abdominal walls. Pathologist evaluations included explant dimensions, inflammation, neovascularization, mature implant tissue, fibrosis, encapsulation, necrosis, mineralization, adhesions, granulomas, and hemorrhages at four and eight weeks post-implantation.
  
  
  RESULTS
  GAG distribution in ADM-R samples was more consistent with native dermis than that in ADM-L samples. Collagen IV was visible in ADM-R, but not in ADM-L. The four-week ADM-R explants showed primarily lymphocytic infiltrates, and less inflammation at eight weeks. The four-week ADM-L explants showed primarily lymphocytic infiltrates, and sustained inflammation at eight weeks. Fibroplasia at four and eight weeks was higher in ADM-L than in ADM-R. Encapsulation, mature connective tissue, and vascular profile scores were comparable between groups. Picrosirius red image analysis showed no significant differences between groups.
  
  
  CONCLUSIONS
  The post-processing matrix characterization and in-vivo response showed notable differences in these ADMs, despite similar allogenic origin. Future investigations into the different matrix composition with regard to fibrosis and inflammation are warranted.
authors.affiliation: RTI Biologics, Inc. Surgical Specialties Department, Alachua, FL, USA. jfaleris@rtix.com
authors.forename: J A
authors.initials: JA
authors.lastname: Faleris
authors.forename: R M C
authors.initials: RM
authors.lastname: Hernandez
authors.forename: D
authors.initials: D
authors.lastname: Wetzel
authors.forename: R
authors.initials: R
authors.lastname: Dodds
authors.forename: D C
authors.initials: DC
authors.lastname: Greenspan
mesh_terms: D034861:Abdominal Wall / Q000098:blood supply* / Q000473:pathology*; D000818:Animals; D001672:Biocompatible Materials; D004549:Elastin / Q000032:analysis; D024022:Fibrillar Collagens / Q000032:analysis*; D006025:Glycosaminoglycans / Q000032:analysis; D007249:Inflammation / Q000473:pathology; D008422:Materials Testing; D023421:Models, Animal; D018919:Neovascularization, Physiologic; D051381:Rats; D017207:Rats, Sprague-Dawley; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D024022:Fibrillar Collagens; D006025:Glycosaminoglycans; D004549:Elastin