title: A morphometric study of mechanotransductively induced dermal neovascularization.
abstract: BACKGROUND
  Mechanical stretch has been shown to induce vascular remodeling and increase vessel density, but the pathophysiologic mechanisms and the morphologic changes induced by tensile forces to dermal vessels are poorly understood.
  
  
  METHODS
  A custom computer-controlled stretch device was designed and applied to the backs of C57BL/6 mice (n=38). Dermal and vascular remodeling was studied over a 7-day period. Corrosion casting and three-dimensional scanning electron microscopy and CD31 staining were performed to analyze microvessel morphology. Hypoxia was assessed by immunohistochemistry. Western blot analysis of vascular endothelial growth factor (VEGF) and mRNA expression of VEGF receptors was performed.
  
  
  RESULTS
  Skin stretching was associated with increased angiogenesis as demonstrated by CD31 staining and vessel corrosion casting where intervascular distance and vessel diameter were decreased (p<0.01). Immediately after stretching, VEGF dimers were increased. Messenger RNA expression of VEGF receptor 1, VEGF receptor 2, neuropilin 1, and neuropilin 2 was increased starting as early as 2 hours after stretching. Highly proliferating epidermal cells induced epidermal hypoxia starting at day 3 (p<0.01).
  
  
  CONCLUSIONS
  Identification of significant hypoxic cells occurred after identification of neovessels, suggesting an alternative mechanism. Increased expression of angiogenic receptors and stabilization of VEGF dimers may be involved in a mechanotransductive, prehypoxic induction of neovascularization.
authors.affiliation: Boston, Mass.; Lausanne, Switzerland; and Mainz, Germany From the Tissue Engineering and Wound Healing Laboratory, Division of Plastic Surgery, and the Laboratory of Adaptive and Regenerative Biology, Department of Surgery, Brigham and Women's Hospital, Harvard Medical School; the Department of Plastic, Reconstructive, and Aesthetic Surgery, University Hospital of Lausanne; the Department of Surgery, Vascular Biology Program, Harvard Medical School, Children's Hospital Boston; and the Institute of Functional and Clinical Anatomy, University Medical Center of the Johannes Gutenberg-University Mainz.
authors.forename: Paolo
authors.initials: P
authors.lastname: Erba
authors.forename: Lino F
authors.initials: LF
authors.lastname: Miele
authors.forename: Avner
authors.initials: A
authors.lastname: Adini
authors.forename: Maximilian
authors.initials: M
authors.lastname: Ackermann
authors.forename: James M
authors.initials: JM
authors.lastname: Lamarche
authors.forename: Britlyn D
authors.initials: BD
authors.lastname: Orgill
authors.forename: Robert J
authors.initials: RJ
authors.lastname: D'Amato
authors.forename: Moritz A
authors.initials: MA
authors.lastname: Konerding
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Mentzer
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Orgill
mesh_terms: D000818:Animals; D015153:Blotting, Western; D049109:Cell Proliferation; D004195:Disease Models, Animal; D004817:Epidermis / Q000502:physiology*; D004847:Epithelial Cells / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D012038:Regeneration / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012867:Skin / Q000098:blood supply* / Q000473:pathology*; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013718:Tensile Strength; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A