Activated protein C promotes neovascularization and neurogenesis in postischemic brain via protease-activated receptor 1

J Neurosci. 2008 Nov 26;28(48):12788-97. doi: 10.1523/JNEUROSCI.3485-08.2008.

Abstract

Activated protein C (APC) is a serine protease with anticoagulant and direct cytoprotective activities. Early postischemic APC application activates the cellular protein C pathway in brain endothelium and neurons, which is neuroprotective. Whether late APC administration after a transient ischemic attack is neuroprotective and whether APC influences brain repair is not known. Here, we determined safety and efficacy of late APC and tissue-plasminogen activator (tPA) administrations in a mouse model of transient brain ischemia. tPA given at 6 h after onset of ischemia killed all mice within 2 d, whereas APC given at 6 or 24 h after ischemia onset improved significantly functional outcome and reduced spread of the ischemic lesion. At 7 d postischemia, APC multiple dosing (0.8 mg/kg, i.p.) at 6-72 or 72-144 h enhanced comparably cerebral perfusion in the ischemic border by approximately 40% as shown by in vivo lectin-FITC angiography, blocked blood-brain barrier leakage of serum proteins, and increased the number of endothelial replicating cells by 4.5- to 4.7-fold. APC multidosing at 6-72 h or 72-144 h increased proliferation of neuronal progenitor cells in the subventricular zone (SVZ) by 40-50% and migration of newly formed neuroblasts from the SVZ toward the ischemic border by approximately twofold. The effects of APC on neovascularization and neurogenesis were mediated by protease-activated receptor 1 and were independent of the reduction by APC of infarction volume. Our data show that delayed APC administration is neuroprotective and mediates brain repair (i.e., neovascularization and neurogenesis), suggesting a significant extension of the therapeutic window for APC intervention in postischemic brain.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Blood-Brain Barrier / drug effects
  • Blood-Brain Barrier / metabolism
  • Blood-Brain Barrier / physiopathology
  • Brain / enzymology
  • Brain / metabolism
  • Brain / physiopathology
  • Brain Infarction / drug therapy
  • Brain Infarction / enzymology
  • Brain Infarction / physiopathology
  • Brain Ischemia / drug therapy*
  • Brain Ischemia / enzymology
  • Brain Ischemia / physiopathology
  • Cell Movement / drug effects
  • Cell Movement / physiology
  • Cell Proliferation / drug effects
  • Cerebral Arteries / enzymology
  • Cerebral Arteries / metabolism
  • Cerebral Arteries / physiopathology
  • Disease Models, Animal
  • Enzyme Activation / physiology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neovascularization, Physiologic / drug effects*
  • Neovascularization, Physiologic / physiology
  • Nerve Regeneration / physiology
  • Neurogenesis / drug effects*
  • Neurogenesis / physiology
  • Protein C / metabolism
  • Protein C / pharmacology*
  • Receptor, PAR-1 / genetics*
  • Recovery of Function / drug effects*
  • Recovery of Function / physiology
  • Reperfusion Injury / enzymology
  • Reperfusion Injury / physiopathology
  • Tissue Plasminogen Activator / toxicity
  • Treatment Outcome

Substances

  • Protein C
  • Receptor, PAR-1
  • Tissue Plasminogen Activator