Inflammation in Vein Graft Disease: A Genetic Approach

描述（由申请人提供）： 主动脉冠状静脉移植物动脉粥样硬化困扰着超过200万美国人。虽然它与自体动脉的动脉粥样硬化有许多共同的特征，但静脉移植物动脉粥样硬化的进展要快得多。由于动脉粥样硬化是一种慢性炎症性疾病，炎性细胞因子如肿瘤坏死因子α（TNF α）可能有助于血管病变的发展。初步研究表明，TNF对体外培养的血管平滑肌细胞（SMC）有很强的致动脉粥样硬化活性。我们的中心假设是TNF在体内对静脉移植失败有很大贡献。虽然活化的巨噬细胞和SMC都可以产生TNF，但这种细胞因子对静脉移植物疾病的贡献以及TNF可能加重静脉移植物动脉粥样硬化的细胞和分子机制尚不完全清楚。为了研究这些问题，我们最近开发了一种新的小鼠静脉移植模型，使用同源下腔静脉颈动脉间置移植物。因此，我们可以独立于受体循环细胞的遗传背景来操纵静脉移植物壁的遗传背景。我们的初步研究显示，当移植到血脂正常的TNFR1-/-受体中时，缺乏TNF受体1信号传导（TNFR1-/-）的移植物中静脉移植物新生内膜形成显著减少（40%）。我们的第一个目的是确定TNF α在正常和高脂血症条件下体内静脉移植物动脉粥样硬化中的作用。为了实现这一目标，我们将使用野生型（C57 Bl/6）或同源载脂蛋白E缺陷（ApoE-/-）小鼠作为同源静脉移植物的促动脉粥样硬化受体。静脉移植物将来自野生型或TNF受体-1缺陷（TNFR1-/-）小鼠。所有受体小鼠还将表达β-半乳糖苷酶标记基因（来自Rosa 26小鼠品系），以允许评价血管源性细胞对静脉移植物的浸润。我们的第二个目的是评估重组TNF抑制剂在血脂水平正常或升高的小鼠中减弱静脉移植物新生内膜形成的潜力。这将通过检查野生型或ApoE-/-小鼠中的静脉移植物重塑来实现，所述小鼠已被我们创建的表达p55TNFR1-IgG融合蛋白的重组腺病毒感染。确定TNF促进静脉移植物动脉粥样硬化的细胞机制可能对许多静脉移植物疾病患者具有治疗意义。

DESCRIPTION (provided by applicant): Aortocoronary vein graft atherosclerosis afflicts over two million Americans. While it shares many features with atherosclerosis of native arteries, vein graft atherosclerosis progresses considerably more rapidly. Inasmuch as atherosclerosis is a chronic inflammatory disorder, inflammatory cytokines such as Tumor Necrosis Factor alpha (TNFalpha) might contribute to vascular lesion development. Preliminary studies demonstrate a strong proatherogenic activity of TNF on vascular smooth muscle cells (SMCs) in vitro. Our Central Hypothesis is that TNF contributes substantially to vein graft failure in vivo. While both activated macrophages and SMCs can produce TNF, the contribution of this cytokine to vein graft disease, and the cellular and molecular mechanisms by which TNF may accentuate vein graft atherosclerosis, are incompletely understood. To study these issues, we recently developed a new murine vein graft model that uses congenic inferior vena cavae to carotid artery interposition grafts. As a result, we can manipulate the genetic background of the vein graft wall independently from that of the recipient's circulating cells. Our preliminary studies show a significant reduction (40%) of vein graft neointima formation in grafts that are deficient in TNF receptor 1 signaling (TNFR1-/-), when placed into normolipidemic TNFR1-/- recipients. Our first aim is to determine the role of TNFalpha in vein graft atherosclerosis under normal and hyperlipidemic conditions in vivo. To achieve this aim, we will use wild type (C57Bl/6) or congenic apolipoprotein E deficient (ApoE-/-) mice as pro-atherogenic recipients of congenic vein grafts. The vein grafts will be derived from either wild type or TNF receptor-1-deficient (TNFR1-/-) mice. All of the recipient mice will also express the beta-galactosidase marker gene (from the Rosa 26 mouse strain) to allow for evaluation of vein graft infiltration by recipient-derived cells. Our second aim is to assess the potential for a recombinant TNF Inhibitor to attenuate vein graft neointima formation in mice with normal or elevated lipid levels. This will be achieved by examining vein graft remodeling in wild-type or ApoE-/- mice, that have been infected with a recombinant adenovirus expressing a p55TNFR1-IgG fusion protein that we have created. Defining cellular mechanisms by which TNF promotes vein graft atherosclerosis may have therapeutic implications for the many patients with vein graft disease.