MMP-2/MMP-9 plasma level and brain expression in cerebral amyloid angiopathy-associated hemorrhagic stroke.

Cerebral amyloid angiopathy (CAA) is one of the main causes of intracerebral hemorrhage (ICH) in the elderly. Matrix metalloproteinases (MMPs) have been implicated in blood–brain barrier disruption and ICH pathogenesis. In this study, we determined the levels MMP-2 and MMP-9 in plasma and their brain expression in CAA-associated hemorrhagic stroke. Although MMP-2 and MMP-9 plasma levels did not differ among patients and controls, their brain expression was increased in perihematoma areas of CAA-related hemorrhagic strokes compared with contralateral areas and nonhemorrhagic brains. In addition, MMP-2 reactivity was found in β-amyloid (Aβ)-damaged vessels located far from the acute ICH and in chronic microbleeds. MMP-2 expression was associated to endothelial cells, histiocytes and reactive astrocytes, whereas MMP-9 expression was restricted to inflammatory cells. In summary, MMP-2 expression within and around Aβ-compromised vessels might contribute to the vasculature fatal fate, triggering an eventual bleeding.