title: In-vivo quantification of the revascularization of a human acellular dermis seeded with EPCs and MSCs in co-culture with fibroblasts and pericytes in the dorsal chamber model in pre-irradiated tissue.
abstract: BACKGROUND
  Transplantation of a cell-seeded graft may improve wound healing after radiotherapy. However, the survival of the seeded cells depends on a rapid vascularization of the graft. Co-culturing of adult stem cells may be a promising strategy to accelerate the vessel formation inside the graft. Thus, we compared the in vivo angiogenic potency of mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) using dorsal skinfold chambers and intravital microscopy.
  
  
  METHODS
  Cells were isolated from rat bone marrow and adipose tissue and characterized by immunostaining and flow cytometry. Forty-eight rats received a dorsal skinfold chamber and were divided into 2 main groups, irradiated and non-irradiated. Each of these 2 groups were further subdivided into 4 groups: unseeded matrices, matrices + fibroblasts + pericytes, matrices + fibroblasts + pericytes + MSCs and matrices + fibroblasts + pericytes + EPCs. Vessel densities were quantified semi-automatically using FIJI.
  
  
  RESULTS
  Fibroblasts + pericytes - seeded matrices showed a significantly higher vascular density in all groups with an exception of non-irradiated rats at day 12 compared to unseeded matrices. Co-seeding of MSCs increased vessel densities in both, irradiated and non-irradiated groups. Co-seeding with EPCs did not result in an increase of vascularization in none of the groups.
  
  
  CONCLUSIONS
  We demonstrated that the pre-radiation treatment led to a significant decreased vascularization of the implanted grafts. The augmentation of the matrices with fibroblasts and pericytes in co-culture increased the vascularization compared to the non-seeded matrices. A further significant enhancement of vessel ingrowth into the matrices could be achieved by the co-seeding with MSCs in both, irradiated and non-irradiated groups.
authors.affiliation: Division of Surgical Oncology and Thoracic Surgery, Department of Surgery, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany. Mario.vitacolonna@medma.uni-heidelberg.de.
authors.forename: M
authors.initials: M
authors.lastname: Vitacolonna
authors.affiliation: Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Belharazem
authors.affiliation: Division of Surgical Oncology and Thoracic Surgery, Department of Surgery, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Hohenberger
authors.affiliation: Division of Surgical Oncology and Thoracic Surgery, Department of Surgery, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
authors.forename: E D
authors.initials: ED
authors.lastname: Roessner
mesh_terms: D062088:Acellular Dermis / Q000378:metabolism / Q000528:radiation effects; D000818:Animals; D002478:Cells, Cultured; D018920:Coculture Techniques; D066026:Endothelial Progenitor Cells / Q000166:cytology* / Q000528:radiation effects; D005347:Fibroblasts / Q000166:cytology* / Q000528:radiation effects; D006801:Humans; D000069416:Intravital Microscopy; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects; D018919:Neovascularization, Physiologic / Q000528:radiation effects; D020286:Pericytes / Q000166:cytology* / Q000528:radiation effects; D051381:Rats; D011916:Rats, Inbred F344; D023822:Tissue Engineering; D014945:Wound Healing / Q000528:radiation effects
keywords: Angiogenic potential adult stem cells; Graft vascularization; Human acellular dermis; In vivo vascularization