A Adiponectina Previne a Reestenose pela Inibição da Proliferação Celular em um Modelo de Enxerto Venoso em Ratos

Impact of Perivascular Adipose Tissue on Neointimal Formation Following Endovascular Placement

Following the placement of endovascular implants, perivascular adipose tissue (PVAT) becomes an early sensor of vascular injury to which it responds by undergoing phenotypic changes characterized by reduction in the secretion of adipocyte-derived relaxing factors and a shift to a proinflammatory and pro-contractile state. Thus, activated PVAT loses its anti-inflammatory function, secretes proinflammatory cytokines and chemokines, and generates reactive oxygen species, which are accompanied by differentiation of fibroblasts into myofibroblasts and proliferation of smooth muscle cells. These subsequently migrate into the intima, leading to intimal growth. In addition, periadventitial vasa vasorum undergoes neovascularization and functions as a portal for extravasation of inflammatory infiltrates and mobilization of PVAT resident stem/progenitor cells into the intima. This review focuses on the response of PVAT to endovascular intervention-induced injury and discusses potential therapeutic targets to suppress the PVAT-initiated pathways that mediate the formation of neointima.

Pentoxifylline Prevents Restenosis by Inhibiting Cell Proliferation via p38MAPK Pathway in Rat Vein Graft Model

Coronary artery bypass grafting remains the gold standard in the therapy of advanced-stage patients. But the vein grafts are prone to restenosis or failure. Pentoxifylline (PTX) is a methylxanthine derivative with a function of inhibiting cell proliferation. We thus applied PTX locally to the vein grafts to study its effect on the inhibition of graft restenosis using a rat vein graft model. Morphometric results showed a significant decrease in the thickness of vein grafts intimal and medial at day 28 after the bypass operation. Results from Western blot and immunohistochemistry showed that PTX also significantly reduced the proliferating cell nuclear antigen (PCNA), alpha-smooth muscle actin (α-SMA) expression, and phosphorylation of p38 in vein grafts. These results firstly discovered the positive role of PTX in preventing the vein grafts restenosis and the mechanism may be inhibition of vascular smooth muscle cells (VSMCs) proliferation via the p38MAPK pathway.