Matrix Metalloproteinase Expression Is Related to Hemorrhagic Transformation After Cardioembolic Stroke

Abstract

Background and Purpose — In animal models of cerebral ischemia, matrix metalloproteinase (MMP) expression was significantly increased and related to blood-brain barrier disruption, edema formation, and hemorrhagic transformation (HT). MMP inhibitors reduce HT after embolic ischemia in tissue-type plasminogen activator-treated animals. We aimed to determine the relationship between MMPs and HT after human ischemic stroke. Methods — Serial MMP-2 and MMP-9 determinations were performed by means of ELISA in 39 cardioembolic strokes in the middle cerebral artery territory. Hemorrhagic events were classified according to clinical and CT criteria (hemorrhagic infarction [HI] and parenchymal hematoma [PH]). HT was evaluated on CT at 48 hours (early HT) and again between day 5 and 7 (late HT). Results — HT was present in 41% of the patients (43.75% early HI, 25% early PH and 31.25% late HI). MMP-2 values were within normal range and were unrelated to HT. Increased expression of MMP-9 (normal range <97 ng/mL) was found among patients with and without HT (159.3±82 versus 143.9±112.6 ng/mL; P =0.64). According to HT subtypes, the highest baseline MMP-9 levels corresponded to patients with late HI (240.4±111.2 versus 102.5±76.7 ng/mL for all other patients, P =0.002). Baseline MMP-9 was the only variable associated with late HI in the multiple logistic regression model (OR 9; CI 1.46, 55.24; P =0.010). Peak of MMP-9 at the 24-hour time point (250.6 ng/mL) was found before appearance of PH. Conclusions — MMPs are involved in some subtypes of HT after human cardioembolic stroke. Baseline MMP-9 level predicts late HI and a 24-hour peak precedes early PH.