Fi02 and Blood Vessel Formation in Adult Lung

Fi02 与成人肺中的血管形成

• 批准号: 6718423
• 负责人: ROSEMARY CRISTIAN JONES
• 金额: $ 38.72万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6718423
• 关键词: angiogenesis; angiopoietins; blood cells; cardiovascular injury; controlled environment chamber; digital imaging; fibroblasts; growth factor receptors; hyperoxia; laboratory rat; lung injury; oxygen tension; platelet derived growth factor; protein tyrosine kinase; pulmonary hypertension; transfection; vascular endothelial growth factors; vascular endothelium

DESCRIPTION (provided by applicant): Injuries that trigger loss of small vessels and capillaries in the adult lung, and wall overgrowth in ones that survive ultimately restrict blood flow and increase vascular resistance and pressure to cause pulmonary hypertension (PH). The long-term goals of the present studies are to obtain data for circulating blood-derived cells that have the potential to form new vascular units in the adult lung, and the RTK-ligand signaling systems that regulate blood vessel formation, as a rational basis for strategies to promote (re)growth of vascular segments and block wall overgrowth. Our recent data in an in vivo model of vascular remodeling in PH indicate that the FiO2 triggers regression and growth of vessel and capillary units to match vascular density to the functional demands of the tissue. Because vessels of the normal alveolar-capillary membrane form the continuation of capillary networks many are simple endothelial-lined channels with few, if any, mural cells. As hyperoxia (FiO2 0.87) prunes these segments, mural cells develop around ones that survive, resulting first in wall support and then in wall overgrowth. The early stage of return to air (representing relative hypoxia to the hyperoxia-adapted lung) triggers further mural cell development and the formation of new vessels and capillaries throughout the alveolar-capillary membrane. Based on preliminary data, the hypotheses tested are that circulating endothelial progenitors (CEPs) form these new vascular networks, and that FiO2 -triggered increase in expression of RTKs for PDGF (PDGFR-alpha and R-beta) by interstitial fibroblasts and ANG- 1 (TIE-2) by local endothelial cells induces mural cell development, and increase in expression of RTKs for VEGF and ANG-2 (VEGFR-1, VEGFR-2 and TIE-2) by CEPs and endothelial cells the formation of vascular units. Blood-derived cells will be characterized by cell lineage analysis. The requirement of PDGFR-beta for mural cell development will be demonstrated by function-inhibition antibody studies. FiO2--induced vascular cell regression, unit pruning, by apoptosis, will be assessed by cell death assays, and the protection afforded by VEGF investigated. Quantitative data will be obtained by state-of-the-art high resolution immunogold labeling and digital imaging techniques for (i) fluorescein labeled/luciferase transfected blood-derived cells and (ii) RTK and ligand (PDGF-AA, PDGF-BB, VEGF, ANG-land ANG-2) expression levels in endothelial and mural cells of forming vascular units in growth responses triggered by the FiO2. These approaches will demonstrate a role for blood derived cells and RTK signaling triggered by an 'abnormal' FiO2 that lead to the formation of new vascular units and wall overgrowth, and provide data on which to base therapeutic approaches to prevent or correct the vascular remodeling that results in severe illness in human patients.

描述（由申请人提供）： 损伤引发成人肺中小血管和毛细血管的损失，以及幸存者的壁过度生长，最终限制血流并增加血管阻力和压力，导致肺动脉高压（PH）。 本研究的长期目标是获得有潜力在成人肺中形成新血管单位的循环血源性细胞的数据，以及调节血管形成的RTK配体信号系统，作为促进血管段（再）生长和阻断血管壁过度生长的策略的合理基础。 我们最近在PH中血管重塑的体内模型中的数据表明，FiO 2触发血管和毛细血管单位的消退和生长，以使血管密度与组织的功能需求相匹配。 由于正常肺泡毛细血管膜的血管形成毛细血管网的延续，许多是简单的内皮衬里通道，几乎没有壁细胞。 由于高氧（FiO 2 0.87）修剪这些节段，壁细胞周围的生存，首先导致壁支持，然后在壁过度生长。 返回空气的早期阶段（代表相对于高氧适应的肺的相对缺氧）触发进一步的壁细胞发育和整个肺泡毛细血管膜的新血管和毛细血管的形成。 基于初步数据，检验的假设是循环内皮祖细胞（CEP）形成这些新的血管网络，并且FiO 2触发PDGF的RTK表达增加间质成纤维细胞的PDGFR-α和R-β以及局部内皮细胞的ANG- 1（TIE-2）诱导壁细胞发育，并增加VEGF和ANG-2的RTK表达VEGFR-1、VEGFR-2和TIE-2通过CEPs和内皮细胞形成血管单位。 将通过细胞谱系分析表征血液来源的细胞。 将通过功能抑制抗体研究证明壁细胞发育对PDGFR-β的需求。 将通过细胞死亡试验评估FiO 2诱导的血管细胞退化、细胞修剪、细胞凋亡，并研究VEGF提供的保护。 将通过最先进的高分辨率免疫金标记和数字成像技术获得定量数据，用于（i）荧光素标记/荧光素酶转染的血液来源细胞和（ii）在FiO 2触发的生长反应中形成血管单位的内皮细胞和壁细胞中的RTK和配体（PDGF-AA、PDGF-BB、VEGF、ANG-1和ANG-2）表达水平。 这些方法将证明血液来源的细胞和RTK信号传导的作用，由“异常”FiO 2触发，导致新的血管单位的形成和血管壁过度生长，并提供数据，作为治疗方法的基础，以预防或纠正导致人类患者严重疾病的血管重塑。