Figure 2. Schematic diagram. Activation of adventitial cells after balloon angioplasty is initially under the influence of perivascular PDGF-B, which elicits phenotypic modulation of adventitial cells to myofibroblasts and mediates their migration toward the lumen with concomitant increases in MMP-2 and collagen deposition, leading to neointimal hyperplasia and loss of luminal area (left hand side). Perivascular adenoviral gene transfer to overexpress the soluble truncated PDGFXR in adventitial compartment antagonizes PDGF-B signaling and attenuates the migration of adventitial cells toward the lumen, decreases MMP-2, but increases TIMP-1 and TIMP-2 expression and diminishes collagen deposition, resulting in reduced neointimal thickness and neointima to media area ratio, thereby ameliorating luminal area loss after balloon angioplasty (right hand side).