Abstract T P207: Matrix Metalloproteinase 3 (MMP3) Exacerbates the Hemorrhagic Transformation in Hyperglycemic Stroke
Acute hyperglycemia (HG) worsens stroke outcomes and increases the risk of cerebral hemorrhage especially with the co-administration of tissue plasminogen activator (tPA). MMP3 mediates tPA-induced hemorrhagic transformation (HT) after stroke. However, the role of MMP3 in hyperglycemic stroke is unknown. The working hypothesis of the current study is that HG upregulates MMP3 activity and worsens vascular injury after stroke and this response is independent of the method of reperfusion.
Methods: Control and mildly HG rats (160-200 mg/dl, achieved by 30% glucose injection (i.p.) 15 min prior to surgery, n=7-9/group) were subjected to either 90 min middle cerebral artery (MCA) suture occlusion and 22.5 h reperfusion, or to humanized thromboembolic stroke. At 24 h, neurological deficit, infarct size, edema, HT occurrence rate (HT index) and tissue hemoglobin (Hb) were measured. MMP3 activity in isolated cerebral microvasculature and/or brain homogenates was quantified by FRET assay. In addition, MMP-3 expression was assessed in brain microvascular endothelial cells (BVEC) subjected to 90 min hypoxia followed by 22.5 h reoxygenation.
Results: While HG did not increase infarct size when compared to control animals, this mild elevation in blood glucose (BG) significantly increased vascular injury indicated by HT index, edema and Hb content in ischemic hemispheres . This was associated with a significant increase in MMP3 activity in both cerebral micro-vasculature and brain homogenates (Table, *p<0.05 vs control). In vitro, the combination of hypoxia and HG has increased MMP3 expression more than each alone (*p<0.05 vs control).
Conclusion: Even mild elevations in BG increased MMP3 activity and augmented vascular injury following ischemic stroke. Our findings suggest that MMP3 might be playing an important role in worsening the outcomes in hyperglycemic stroke and MMP3 inhibition may be a potential therapeutic target.
Author Disclosures: S. Hafez: None. M. Abdelsaid: None. N. Hoda: None. M. Coucha: None. S. Fagan: None. A. Ergul: None.
This research has received full or partial funding support from the American Heart Association, Greater Southeast Affiliate – Alabama, Florida, Georgia, Louisiana, Mississippi, Puerto Rico, Tennessee, U.S. Virgin Islands.
- © 2014 by American Heart Association, Inc.