ADENOVIRUS-MEDIATED GENE-TRANSFER OF THE HUMAN TISSUE INHIBITOR OF METALLOPROTEINASE-2 BLOCKS VASCULAR SMOOTH-MUSCLE CELL INVASIVENESS IN-VITRO AND MODULATES NEOINTIMAL DEVELOPMENT IN-VIVO

Background-Endovascular injury induced by balloon withdrawal leads to the increased activation of matrix metalloproteinases (MMPs) in the va scular wall, allowing smooth muscle cells (SMCs) to digest the surroun ding extracellular matrix (ECM) and migrate from the media into the in tima. The objective of this study was to examine the effects of a repl ication-deficient adenovirus carrying the cDNA for human tissue inhibi tor of metalloproteinase-2 (AdCMV.hTIMP-2) on SMC function in vitro an d neointimal development in the injured rat carotid artery. Methods an d Results-Infection of cultured rat aortic SMCs at a multiplicity of i nfection of 100 with AdCMV.hTIMP-2 resulted in high-level expression o f hTIMP-2 mRNA and protein secretion into the medium. Conditioned medi a (CM) from AdCMV.hTIMP-2-infected but not control virus (AdCMV.null o r AdCMV.beta gal)-infected SMCs inhibited MMP-2 activity on gelatin zy mograms as well as the chemoattractant-directed migration of SMCs acro ss reconstituted basement membrane proteins in the Boyden chamber assa y. In contrast, AdCMV.hTIMP-2 CM had no effect on chemoattractant-dire cted migration of SMCs occurring in the absence of an ECM barrier or o n the proliferation of cultured neointimal SMCs, Delivery of AdCMV.hTI MP-2 (2.5 X 10(9) pfu) to the carotid artery wall at the time of ballo on withdrawal injury inhibited SMC migration into the intima by 36% (P < 0.05) at 4 days and neointimal area by 53% (P < 0.01) at 8 days and by 12% (P=NS) at 21 days after injury. AdCMV.hTIMP-2 had no effect on medial area. Conclusions-Adenovirus-mediated hTIMP-2 gene transfer in hibits SMC invasiveness in vitro and in vivo and delays neointimal dev elopment after carotid injury.