Adenovirus-mediated gene transfer of TIMP-4 reduces neointimal hyperplasia in balloon-injured rat carotid artery

ObjectiveTo determine the effects of a recombinant replication-deficient adenovirus encoding human tissue inhibitor of metalloproteinase-4 (Ad.TIMP-4) on vascular smooth muscle cell (VSMC) function in vitro and neointimal development in the injured rat carotid artery.MethodsWestern blotting, gelatin zymography and reverse zymography were used to characterize the expression and functional activity of the TIMP-4 secreted by Ad.TIMP-4-infected VSMCs. The migration and proliferation of VSMCs in vitro were separately detected by using Millicell-PCF invasion chambers and [3H]-thymidine incorporation assay. Immunohistochemistry and morphometric analysis were used to determine the local expression of TIMP-4 and its effect on neointima development in a rat carotid artery balloon injury model.ResultsVSMCs infected with Ad.TIMP-4 expressed functionally active human TIMP-4 which increased with the duration of infection. TIMP-4 expression inhibited VSMC migration, but not significantly affect VSMC proliferation. In a balloon-injured rat carotid artery model, a significant 62% reduction in neointimal area was found in Ad.TIMP-4–infected vessels at 14 days after injury. Ad.TIMP-4 infection had no effect on medial area.ConclusionOur results indicated TIMP-4 over expression can significantly inhibit the migration of cultured VSMCs and prevent neointimal formation after vascular injury. Our findings provide additional evidence that TIMP-4 could play an important role in vascular pathophysiology, and may be an important therapeutic target for future drug development.