title: Age-associated induction of cell membrane CD47 limits basal and temperature-induced changes in cutaneous blood flow.
abstract: OBJECTIVE
  We tested the hypothesis that the matricellular protein thrombospondin-1 (TSP1), through binding to and activation of the cell receptor CD47, inhibits basal and thermal-mediated cutaneous blood flow.
  
  
  BACKGROUND
  Abnormal and decreased cutaneous blood flow in response to temperature changes or vasoactive agents is a feature of cardiovascular disease and aging. The reasons for decreased cutaneous blood flow remain incompletely understood. Furthermore, a role for matricellular proteins in the regulation skin blood flow has never been proposed.
  
  
  METHODS
  C57BL/6 wild type, TSP1-null, and CD47-null 12- and 72-week-old male mice underwent analysis of skin blood flow (SkBF) via laser Doppler in response to thermal stress and vasoactive challenge.
  
  
  RESULTS
  Young and aged TSP1- and CD47-null mice displayed enhanced basal and thermal sensitive SkBF changes compared with age-matched wild type controls. Nitric oxide-mediated increases in SkBF were also greater in null mice. TSP1 and CD47 were expressed in skin from young wild type mice, and both were significantly upregulated in aged animals. Tissue 3',5'-cyclic guanosine monophosphate, a potent vasodilator, was greater in skin samples from null mice compared with wild type regardless of age. Finally, treating wild type animals with a CD47 monoclonal antibody that inhibits TSP1 activation of CD47 enhanced SkBF in both young and aged animals.
  
  
  CONCLUSIONS
  These results suggest that secreted TSP1, via its cognate receptor CD47, acutely modulates SkBF. These data further support therapeutically targeting CD47 to mitigate age-associated loss of SkBF and maximize wound healing.
authors.affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
authors.forename: Natasha M
authors.initials: NM
authors.lastname: Rogers
authors.forename: David D
authors.initials: DD
authors.lastname: Roberts
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Isenberg
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001794:Blood Pressure / Q000502:physiology; D051928:CD47 Antigen / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D017078:Laser-Doppler Flowmetry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D012867:Skin / Q000098:blood supply* / Q000378:metabolism*; D013696:Temperature; D019700:Thrombospondin 1 / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D051928:CD47 Antigen; D012333:RNA, Messenger; D019700:Thrombospondin 1; D009569:Nitric Oxide; D006152:Cyclic GMP