title: PAI-1-derived peptide EEIIMD prevents hypoxia/ischemia-induced aggravation of endothelin- and thromboxane-induced cerebrovasoconstriction.
abstract: BACKGROUND
  Babies are frequently exposed to cerebral hypoxia and ischemia (H/I) during the perinatal period as a result of stroke, problems with delivery or post delivery respiratory management. The sole FDA approved treatment for acute stroke is tissue-type plasminogen activator (tPA). Endogenous tPA is upregulated and potentiates impairment of pial artery dilation in response to hypotension after H/I in pigs. Mitogen-activated protein kinase (MAPK), a family of at least 3 kinases, ERK, p38 and JNK, is also upregulated after H/I, with ERK contributing to impaired vasodilation. This study examined the hypothesis that H/I aggravates the vascular response to two important procontractile mediators released during CNS ischemia, endothelin-1 (ET-1) and thromboxane, which is further enhanced by tPA and ERK MAPK.
  
  
  METHODS
  Cerebral hypoxia (pO(2) 35 mmHg for 10 min via inhalation of N(2)) followed immediately by ischemia (global intracranial pressure elevation for 20 min) was produced in chloralose anesthetized piglets equipped with a closed cranial window.
  
  
  RESULTS
  H/I aggravated pial artery vasconstriction induced by ET-1 and the thromboxane mimetic U 46619. Potentiated vasoconstrictor responses were blocked by EEIIMD, an inhibitor of tPA's signaling and vascular activities, but unchanged by its inactive analogue EEIIMR. The cerebrospinal fluid concentration of ERK MAPK determined by ELISA was increased by H/I, potentiated by tPA, but blocked by EEIIMD. The ERK MAPK antagonist U 0126 blocked H/I augmented enhancement of ET-1 and U 46619 vasoconstriction.
  
  
  CONCLUSIONS
  These data indicate that H/I aggravates ET-1 and thromboxane mediated cerebral vasoconstriction by upregulating endogenous tPA and ERK MAPK.
authors.affiliation: Department of Anesthesiology and Critical Care, University of Pennsylvania, 3620 Hamilton Walk, JM3, Philadelphia, PA, l9l04, USA, armsteaw@uphs.upenn.edu.
authors.forename: William M
authors.initials: WM
authors.lastname: Armstead
authors.forename: John
authors.initials: J
authors.lastname: Riley
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Cines
authors.forename: Abd Al-Roof
authors.initials: AA
authors.lastname: Higazi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000098:blood supply* / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D003399:Craniotomy / Q000379:methods; D004195:Disease Models, Animal; D019332:Endothelin-1 / Q000494:pharmacology*; D005260:Female; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy*; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology*; D010841:Pia Mater / Q000098:blood supply; D017395:Plasminogen Activator Inhibitor 1 / Q000494:pharmacology*; D013552:Swine; D013931:Thromboxanes / Q000494:pharmacology*; D057170:Translational Research, Biomedical; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D019332:Endothelin-1; D009842:Oligopeptides; D017395:Plasminogen Activator Inhibitor 1; D013931:Thromboxanes; D014662:Vasoconstrictor Agents; C513663:glutamyl-glutamyl-isoleucyl-isoleucyl-methionyl-aspartic acid