Endothelial Cell Dysfunction in Pulmonary Arterial Hypertension

特发性（原发性）肺动脉高压（IPAH）是丛源性肺动脉高压（PAH）的一个亚组，是一种罕见的疾病，具有严重的发病率和高死亡率。 在IPAH或更广泛的PAH组中，没有常规筛查试验或经验证的疾病活动性标志物。 因此，患者通常处于疾病的晚期阶段。IPAH和其他形式PAH的发病机制尚不清楚。目前的想法集中在一个两击假说：1）遗传易感性，和2）触发刺激，启动肺血管损伤，导致内皮细胞功能障碍。 内皮细胞通常脱落到循环中，并且是用于研究以内皮细胞功能障碍为特征的疾病的有价值的临床材料来源。 不幸的是，没有明确的方法存在用于分离临床相关数量的循环内皮细胞（CEC）。在该项目的实验室阶段，我们计划使用流式细胞术开发一种方法来分离临床相关数量的活CEC。 我们假设CEC可用于定义IPAH和其他形式PAH中差异调节生物标志物的子集，这可能导致早期诊断和更好的治疗反应测量方法。 我们还希望为未来的治疗干预确定新的靶点。 在项目的临床阶段，我们将招募以下受试者群体：1）IPAH和其他形式PAH患者（血管损伤诱导的肺动脉高压），目前未接受任何治疗，静脉治疗时间少于或等于6个月，或小于或等于1年的口服治疗2）归因于非血管损伤过程的肺动脉高压（PH）患者和3）正常人（对照组）。 所有受试者将接受右心导管插入术。将通过细胞表面标志物和寡核苷酸微阵列表征外周和从肺动脉导管抽取的CEC的疾病表型。 将通过细胞分选从CEC制备用于微阵列的总RNA并进行扩增。 此外，还将分离外周血单核细胞（PBMC）。将使用高密度寡核苷酸微阵列深入研究PBMC，以更全面地表征其转录组。我们计划通过重新研究IPAH或PAH患者在治疗干预后的相同参数来随访治疗反应。 我们于2006年6月开始积极参与该议定书的试验阶段。 迄今为止，我们已招募了26人。

Idiopathic (primary) pulmonary arterial hypertension (IPAH), a subgroup of plexogenic pulmonary arterial hypertension (PAH), is a rare disorder associated with severe morbidity and high mortality rates. There are no routine screening tests or validated markers of disease activity in IPAH, or the broader group of PAH. Therefore, patients usually present at advanced stages of disease. The pathogenesis of IPAH and other forms of PAH remain unclear. Current thinking focuses on a two-hit hypothesis: 1) genetic susceptibility, and 2) a triggering stimulus that initiates pulmonary vascular injury, resulting in endothelial cell dysfunction. Endothelial cells are normally shed into the circulation and are a valuable source of clinical material for studying diseases characterized by endothelial cell dysfunction. Unfortunately, no clear methodology exists for isolating clinically relevant numbers of circulating endothelial cells (CECs). In the bench phase of the project we plan to use flow cytometry to develop a methodology for isolating clinically relevant numbers of viable CECs. We hypothesize that CECs can be used to define a subset of differentially regulated biomarkers in IPAH and other forms of PAH that may lead to earlier diagnosis and better methods for measuring responses to therapy. We also hope to identify novel targets for future therapeutic interventions. In the clinical phase of the project, we will recruit the following subject groups: 1) patients with IPAH and other forms of PAH (vascular injury-induced pulmonary hypertension) who currently are on no therapy, less than or equal to 6 months of IV therapy, or less than or equal to one year of oral therapy 2) patients with pulmonary hypertension (PH) ascribed to a nonvascular injury process and 3) normal individuals (controls). All subjects will undergo right heart catheterization. CECs drawn peripherally and from the pulmonary artery catheter will be characterized for disease phenotype by cell surface markers and oligonucleotide microarrays. Total RNA for microarrays will be prepared from CECs by cell sorting and subjected to amplification. In addition peripheral blood mononuclear cells (PBMCs) will also be isolated. PBMCs will be studied in depth using high density oligonucleotide microarrays to more fully characterize their transcriptome. We plan to follow response to therapy by restudying the same parameters in patients with IPAH or PAH after therapeutic intervention. We started actively enrolling into the pilot phase of the protocol in June 2006. We have enrolled 26 individuals to date.