Matrix Metalloprotease 3 Exacerbates Hemorrhagic Transformation and Worsens Functional Outcomes in Hyperglycemic Stroke
Background and Purpose—Acute hyperglycemia worsens the clinical outcomes and exacerbates cerebral hemorrhage after stroke. The mediators of hemorrhagic transformation (HT) in hyperglycemic stroke are not fully understood. Matrix metalloproteinase 3 (MMP3) plays a critical role in the tissue plasminogen activator–induced HT. However, the role of MMP3 in exacerbating the HT and worsening the functional outcomes in hyperglycemic stroke remains unknown.
Methods—Control/normoglycemic and hyperglycemic (blood glucose, 140–200 mg/dL) male Wistar rats were subjected to middle cerebral artery occlusion for 90 minutes and either 24 hours or 7 days reperfusion. MMP3 was inhibited pharmacologically (UK 356618, 15 mg/kg IV at reperfusion) or knocked down in the brain by shRNA lentiviral particles (injected intracerebroventricular). Neurovascular injury was assessed at 24 hours, and functional outcomes were assessed at 24 hours, day 3, and day 7. MMP3 activity was measured in brain homogenate and cerebral macrovessels. Localization of MMP3 within the neurovascular unit after hyperglycemic stroke was demonstrated by immunohistochemistry.
Results—Hyperglycemia significantly increased MMP3 activity in the brain after stroke, and this was associated with exacerbated HT and worsened functional outcomes. MMP3 inhibition significantly reduced HT and improved functional outcomes.
Conclusions—MMP3 plays a critical role in mediating cerebrovascular injury in hyperglycemic stroke. Our findings point out MMP3 as a potential therapeutic target in hyperglycemic stroke.
- Received August 21, 2015.
- Revision received December 10, 2015.
- Accepted December 27, 2015.
- © 2016 American Heart Association, Inc.