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Pathophysiologic responses in brain after stroke are highly complex. Thus far, a singular focus on saving neurons alone has not revealed any clinically effective neuroprotectants. To address this limitation, the concept of a neu-rovascular unit was developed. Within this conceptual framework, brain function and dysfunction are manifested at the level of cell–cell signaling between neuronal, glial and vascular elements. | MINIREVIEW Brain angiogenesis in developmental and pathological processes neurovascular injury and angiogenic recovery after stroke Ken Arai Guang Jin Deepti Navaratna and Eng H. Lo Neuroprotection Research Laboratory Massachusetts General Hospital Harvard MedicalSchool Charlestown MA USA Keywords angiogenesis edema endothelialprogenitor cell hemorrhage ischemia matrix metalloproteinase neurogenesis neurovascular unit remodeling stroke Correspondence K. Arai Neuroprotection Research Laboratory Massachusetts General Hospital Room 2414 149 13th St Charlestown MA 02129 USA Fax 1 617 726 7830 Tel 1 617 724 9503 E-mail karai@partners.org Received 19 February 2009 revised 1 May 2009 accepted 8 May 2009 doi 10.1111 j.1742-4658.2009.07176.x Pathophysiologic responses in brain after stroke are highly complex. Thus far a singular focus on saving neurons alone has not revealed any clinically effective neuroprotectants. To address this limitation the concept of a neurovascular unit was developed. Within this conceptual framework brain function and dysfunction are manifested at the level of cell-cell signaling between neuronal glial and vascular elements. For stroke coordinated responses at the neurovascular interface will mediate acute as well as chronic events in ischemic and hemorrhagic brain tissue. In this minireview we briefly survey two representative examples of neurovascular responses in stroke. During the early acute phase of neurovascular injury bloodbrain barrier perturbations should predominate with key roles for various matrix proteases. During the delayed phase brain angiogenesis may provide the critical neurovascular substrates for neuronal remodeling. In this minireview we propose the hypothesis that the biphasic nature of neurovascular responses represents an endogenous attempt by damaged parenchyma to trigger brain angiogenesis and repair. This phenomenon may allow acute deleterious signals to transition into beneficial effects during stroke recovery. .
