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Aging, Angiogenesis, and the Neuropeptide Y (NPY) System

衰老、血管生成和神经肽 Y (NPY) 系统

基本信息

批准号：
6479269
负责人：
Joanna B. Kitlinska
金额：
$ 7.76万
依托单位：
GEORGETOWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-04-01 至 2004-03-31
项目状态：
已结题

项目摘要

Age-dependent impairment of angiogenesis leads to increased progression of ischemic vascular diseases, delayed wound healing, as well as slower tumor growth and spread. The mechanisms of reduced angiogenesis have not been fully elucidated yet but may include alterations in endothelial responsiveness, cell-matrix interactions and lack of angiogenic factors and their receptors. Neuropeptide Y (NPY) is commonly known as a sympathetic transmitter and vasoconstrictor. Recent our laboratory has established its new and potent activities as an angiogenic and mitogenic factor for vascular smooth muscle and endothelial cells in vitro, and in vivo in the rat hindlimb ischemic model. The overall goal of this research is to establish if alternations in the NPY system are involved in the age-related impairment of angiogenesis. The specific aims are to determine if: 1) NPY-mediated angiogenesis is diminished with age; 2) NPY synthesis/release occurring under physiological condition and in response to angiogenic stimuli is reduced in aged animals; 3) expression of the NPY angiogenic receptors (Y1, Y2, Y5) and its converting enzyme dipeptidyl peptidase IV (DPPIV, which converts NPY to an angiogenically active fragment, NPY3-36) is altered with age 4) age-related changes in NPY angiogenic systems are due to decreased levels of basic fibroblast growth factor (bFGF) in aging. These studies will be perform4ed on both animal (young and aged mice) and cellular models. Spontaneous, as well as NPY- and bFGF-induced sprouting of mouse aortas will be compared between both age groups. The mouse hindlimb ischemic model will be employed to determine the effect of aging on NPY-induced angiogenesis in ischemia. New vessels will be detected by CD31 immunostaining and by their casting by perfusion with latex. Systemic and local NPY levels, as well as expression of angiogenic stimuli, will be determined. The cellular model will include NPY stimulation of aortic endothelial cells from young and aged mice and measuring their mitogenic response in parallel to the expression of NPY receptors. Interactions between bFGF and NPY angiogenic systems and their age-related modulations will be established by determining the levels of growth factors and NPY receptors in ischemic tissues of aged and young animals, also after NPY or bFGF treatment. Moreover, cross-inhibition with neutralizing antibody of bFGF- and NPY-induced neovascularization as well as bFGF-mediated angiogenesis in Y2 knockout mice will be investigated using aortic sprouting assay. This research will help to establish the mechanism(s) of age-related changes in angiogenesis, which may have important implications for the development of ne2w therapeutic strategies in older patients-an enhancement of angiogenesis in the ischemic disease.

年龄依赖性血管生成损伤会导致缺血性血管疾病进展加快、伤口愈合延迟以及肿瘤生长和扩散减慢。血管生成减少的机制尚未完全阐明，但可能包括内皮反应性的改变、细胞-基质相互作用以及血管生成因子及其受体的缺乏。神经肽 Y (NPY) 通常被称为交感神经递质和血管收缩剂。最近，我们的实验室在体外和大鼠后肢缺血模型中确定了其作为血管平滑肌和内皮细胞的血管生成和有丝分裂因子的新的有效活性。本研究的总体目标是确定 NPY 系统的改变是否与年龄相关的血管生成损伤有关。具体目标是确定：1）NPY 介导的血管生成是否随着年龄的增长而减少； 2) 在老年动物中，生理条件下和对血管生成刺激的反应中发生的 NPY 合成/释放减少； 3) NPY 血管生成受体 (Y1、Y2、Y5) 及其转化酶二肽基肽酶 IV (DPPIV，将 NPY 转化为血管生成活性片段 NPY3-36) 的表达随着年龄的增长而改变 4) NPY 血管生成系统中与年龄相关的变化是由于衰老过程中碱性成纤维细胞生长因子 (bFGF) 水平降低所致。这些研究将在动物（年轻和老年小鼠）和细胞模型上进行。将比较两个年龄组之间自发的以及 NPY 和 bFGF 诱导的小鼠主动脉发芽。小鼠后肢缺血模型将用于确定衰老对 NPY 诱导的缺血血管生成的影响。新血管将通过 CD31 免疫染色和乳胶灌注铸型来检测。将确定全身和局部 NPY 水平以及血管生成刺激的表达。该细胞模型将包括对年轻和老年小鼠的主动脉内皮细胞进行 NPY 刺激，并与 NPY 受体表达平行地测量它们的有丝分裂反应。 bFGF 和 NPY 血管生成系统之间的相互作用及其与年龄相关的调节将通过测定老年和幼龄动物缺血组织中生长因子和 NPY 受体的水平来确定，也可以在 NPY 或 bFGF 治疗后进行。此外，将使用主动脉萌芽试验研究 Y2 敲除小鼠中 bFGF 和 NPY 诱导的新血管形成以及 bFGF 介导的血管生成与中和抗体的交叉抑制。这项研究将有助于建立与年龄相关的血管生成变化的机制，这可能对开发老年患者的新治疗策略（增强缺血性疾病中的血管生成）具有重要意义。