Nerve growth factor – The key factor in endothelial aging, angiogenesis and gastric ulcer healing

 描述（由申请人提供）： 背景/依据：血管生成-新毛细血管的形成是组织损伤（例如胃糜烂（GE）和溃疡（GU））愈合所必需的基本过程。老年人和大鼠的胃粘膜（老年胃粘膜）表现出对损伤的易感性增加、血管生成受损和愈合延迟。[Our总体假设是神经生长因子（NGF）对于胃内皮细胞（EC）活力、功能、血管生成和GU愈合是关键的，并且衰老EC中的NGF缺乏是衰老个体中胃血管生成和GU愈合的衰老相关损伤的主要机制。这一假设的基本原理源于我们的初步研究，表明：1）老化胃EC（AGEC）具有降低的NGF表达，并且NGF蛋白和/或NGF基因治疗恢复老化EC细胞中的体外血管生成并逆转NSAID诱导的血管生成抑制，和[2]用NGF局部治疗老化大鼠中的GU显著增加了NGF和VEGF的局部表达，血管生成，加速溃疡愈合，并改善粘膜再生。我们的具体目标是确定是否以及在多大程度上：1）NGF及其信号传导对于胃EC的活力、功能和血管生成至关重要，并确定其作用机制。 潜在的分子机制; 2）NGF缺乏症：（a）EC老化和EC增殖和血管生成的老化相关损伤的关键机制和（B）NGF治疗或NGF基因治疗是否恢复老化EC中的体外血管生成; [3]用NGF局部治疗老化大鼠中的GU将改善血管再生和GU愈合，以及这些事件是否可以使用共聚焦激光显微内镜（CLE）在体内和真实的时间可视化。]我们的长期目标是发现新的机制，调节胃血管生成和其损害的老化，提供一个基础的治疗性使用的神经生长因子，以改善血管生成和愈合的GU在老龄化的个人和使用CLE在体内评估GU愈合，血管再生和确定GU疤痕异常，可能是溃疡复发的基础。设计图：由于EC是血管生成的关键靶点和效应器，因此，在从年轻和衰老大鼠胃粘膜分离的EC的体外研究中，我们将确定EC功能的衰老相关损伤的机制，NGF、VEGF及其受体的表达，PI 3 K/Akt和MAPK信号传导，以及NGF在EC存活、迁移、增殖和血管生成中的作用。接下来，我们将在体内检查老年大鼠和年轻大鼠GU愈合和血管再生的顺序事件，并确定局部注射NGF是否会改善老年大鼠GU愈合和预防NSAID诱导的GU复发。我们还将使用来自年轻和老年个体的GU的人类标本来确定我们的实验结果的人类相关性。意义：我们项目的中心主题是新血管形成，损伤愈合和衰老的影响。2006年，约3900万美国人（占人口的12%）年龄在65岁或以上，预计到2030年这一数字将达到约7000万。这一人群的组织和器官损伤以及GU并发症的风险很高。衰老中血管生成受损是延迟愈合、发病率和死亡率的关键因素。[最近的研究表明，非H。幽门螺杆菌，非NSAID溃疡（“特发性”溃疡）正在增加，它们占所有溃疡的30%， 有“特发性”出血性溃疡病史的人复发性溃疡出血的风险很高，死亡率也很高（83 - 92%）。因此，GU复发及其并发症仍然是重要的临床问题，特别是在老年和重症患者中。拟议的研究将提供深入了解新的机制和调节作用的神经生长因子和血管生成GU愈合和他们的关系，这些过程中与年龄相关的损害。这一新的信息可以适用于其他领域的粘膜愈合，包括炎症性肠病，食管糜烂和溃疡，以及癌症相关的新血管形成。

 DESCRIPTION (provided by applicant): Background/Rationale: Angiogenesis - formation of new capillary blood vessels is a fundamental process essential for healing of tissue injury, e.g. gastric erosions (GE) and ulcers (GU). Gastric mucosa of aging humans and rats (aging gastric mucosa) exhibits increased susceptibility to injury, impaired angiogenesis and delayed healing. [Our overall hypothesis is that nerve growth factor (NGF) is critical for gastric endothelial cell (EC) viability, function, angiogenesis and GU healing, and that NGF deficiency in aging ECs is the major mechanism of aging-related impairment of gastric angiogenesis and GU healing in aging individuals.] The rationale for this hypothesis stems from our preliminary studies showing that: 1) aging gastric ECs (AGECs) have reduced expression of NGF, and NGF protein and/or NGF gene therapy restores in vitro angiogenesis in aging ECs cells and reverses NSAIDs-induced inhibition of angiogenesis, and [2) local treatment of GU in aging rats with NGF significantly increases local expression of NGF and VEGF, angiogenesis, accelerates ulcer healing, and improves mucosal regeneration.] Our specific objectives are to determine whether and to what extent: 1) NGF and its signaling are critical for gastric ECs viability, function and angiogenesis and to identify the underlying molecular mechanisms; 2) NGF deficiency is: (a) crucial mechanism for ECs' aging and for aging-related impairment of EC proliferation and angiogenesis and (b) whether NGF treatment or NGF gene therapy restores in vitro angiogenesis in aging ECs; [3) Local treatment of GUs in aging rats with NGF will improve vascular regeneration and GU healing and whether these events can be visualized in vivo and in real time using confocal laser endomicroscopy (CLE).] Our long-term objective is to uncover novel mechanisms that regulate gastric angiogenesis and its impairment in aging, to provide a basis for the therapeutic use of NGF to improve angiogenesis and healing of GU in aging individuals and to use CLE for in vivo assessment of GU healing, vascular regeneration and for identifying GU scar abnormalities that may be the basis for the ulcer recurrence. Design: Since ECs are critical targets and effectors of angiogenesis, in in vitro studies in ECs isolated from gastric mucosa of young and aging rats we will determine the mechanisms underlying aging related impairment of EC functions, expression of NGF, VEGF, their receptors, PI3K/Akt and MAPK signaling, and the role of NGF in EC survival, migration, proliferation and angiogenesis. Next we will examine in vivo in aging and young rats sequential events of GU healing and vascular regeneration and will determine whether locally injected NGF will improve GU healing in aging rats and prevent NSAIDs-induced GU recurrence. We will also determine human relevance of our experimental findings using human specimens of GUs from young and aging individuals. Significance: The central topic of our project is neovascularization, injury healing and impact of aging. In 2006, ~39 million Americans (12% of population) were 65 years of age or older, and this number is projected to reach ~70 million by 2030. This population is at high risk of tissue and organ injuries, and GU complications. Impaired angiogenesis in aging is a key factor in delayed healing, morbidity and mortality. [Recent studies indicate that the incidence of non-H. pylori, non-NSAIDs ulcers ("idiopathic" ulcers) is increasing and they constitute up to 30% of all ulcers and patients with a history of "idiopathic" bleeding ulcers have a high risk of recurrent ulcer bleeding and a high mortality 83 - 92%. Therefore the GU recurrence and its complications still remain important clinical issue, especially in aging and severely ill patients.] The proposed studies will provide insight into novel mechanisms and the regulatory role of NGF and angiogenesis in GU healing and their relation to aging-related impairment of these processes. This novel information can be applicable to other areas of mucosal healing including inflammatory bowel disease, esophageal erosions and ulcers, as well as to cancer-related neovascularization.