title: Ca²⁺-dependent nitric oxide release in the injured endothelium of excised rat aorta: a promising mechanism applying in vascular prosthetic devices in aging patients.
abstract: BACKGROUND
  Nitric oxide is key to endothelial regeneration, but it is still unknown whether endothelial cell (EC) loss results in an increase in NO levels at the wound edge. We have already shown that endothelial damage induces a long-lasting Ca²⁺ entry into surviving cells though connexin hemichannels (CxHcs) uncoupled from their counterparts on ruptured cells. The physiological outcome of injury-induced Ca²⁺ inflow is, however, unknown.
  
  
  METHODS
  In this study, we sought to determine whether and how endothelial scraping induces NO production (NOP) in the endothelium of excised rat aorta by exploiting the NO-sensitive fluorochrome, DAF-FM diacetate and the Ca²⁺-sensitive fluorescent dye, Fura-2/AM.
  
  
  RESULTS
  We demonstrated that injury-induced NOP at the lesion site is prevented in presence of the endothelial NO synthase inhibitor, L-NAME, and in absence of extracellular Ca²⁺. Unlike ATP-dependent NO liberation, the NO response to injury is insensitive to BTP-2, which selectively blocks store-operated Ca²⁺ inflow. However, injury-induced NOP is significantly reduced by classic gap junction blockers, and by connexin mimetic peptides specifically targeting Cx37Hcs, Cx40HCs, and Cx43Hcs. Moreover, disruption of caveolar integrity prevents injury-elicited NO signaling, but not the accompanying Ca²⁺ response.
  
  
  CONCLUSIONS
  The data presented provide the first evidence that endothelial scraping stimulates NO synthesis at the wound edge, which might both exert an immediate anti-thrombotic and anti-inflammatory action and promote the subsequent re-endothelialization.
authors.forename: Roberto
authors.initials: R
authors.lastname: Berra-Romani
authors.forename: José Everardo
authors.initials: JE
authors.lastname: Avelino-Cruz
authors.forename: Abdul
authors.initials: A
authors.lastname: Raqeeb
authors.forename: Alessandro
authors.initials: A
authors.lastname: Della Corte
authors.forename: Mariapia
authors.initials: M
authors.lastname: Cinelli
authors.forename: Stefania
authors.initials: S
authors.lastname: Montagnani
authors.forename: Germano
authors.initials: G
authors.lastname: Guerra
authors.forename: Francesco
authors.initials: F
authors.lastname: Moccia
authors.forename: Franco
authors.initials: F
authors.lastname: Tanzi
mesh_terms: D000367:Age Factors; D000368:Aged; D000818:Animals; D001011:Aorta / Q000378:metabolism* / Q000601:surgery; D001807:Blood Vessel Prosthesis; D002118:Calcium / Q000502:physiology*; D004730:Endothelium, Vascular / Q000293:injuries / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009569:Nitric Oxide; D002118:Calcium