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An imbalance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) contributes to the left ventricle (LV) remodeling that occurs after myocardial infarction (MI). However, translation of these observations into a clinically relevant, therapeutic strategy remains to be established. The present study investigated targeted TIMP augmentation through regional injection of a degradable hyaluronic acid hydrogel containing recombinant TIMP-3 (rTIMP-3) in a large animal model. MI was induced in pigs by coronary ligation. Animals were then randomized to receive targeted hydrogel/rTIMP-3, hydrogel alone, or saline injection and followed for 14 days. Instrumented pigs with no MI induction served as referent controls. Multimodal imaging (fluoroscopy/echocardiography/magnetic resonance imaging) revealed that LV ejection fraction was improved, LV dilation was reduced, and MI expansion was attenuated in the animals treated with rTIMP-3 compared to all other controls. A marked reduction in proinflammatory cytokines and increased smooth muscle actin content indicative of myofibroblast proliferation occurred in the MI region with hydrogel/rTIMP-3 injections. These results provide the first proof of concept that regional sustained delivery of an MMP inhibitor can effectively interrupt adverse post-MI remodeling.
Eckhouse et al. (Wed,) studied this question.