A Natural History Study of Novel Biomarkers in Pulmonary Arterial Hypertension

肺动脉高压（WHO I组）是一种罕见的疾病与生存率低。由1）遗传易感性和2）引发肺血管损伤的触发刺激（两次打击假说）导致的内皮功能障碍似乎在PAH的发病机制和进展中发挥核心作用。炎症似乎驱动这种功能失调的内皮表型，在遗传易感的IPAH和DaPAH患者中传播损伤和修复周期。然而，尽管有越来越多的证据表明PAH患者存在血管炎症，但缺乏关于该过程的时间演变及其对右心室（RV）和肺血管重塑的贡献的详细表型研究。 在该方案中，通过超声心动图、6分钟步行、心肺负荷测试、肺功能测试、心脏CT、高级心脏MRI技术、基因表达谱和血清生物标志物对受试者进行全面表征。我们假设，这些受试者的详细特征，结合PAH中血管炎症的时间演变及其对RV和肺血管功能的影响的更严格的概况，将为传统的疾病严重程度测量增加预后价值，并为未来的研究提出新的治疗靶点。 该方案最初于2012年10月获得NHLBI IRB批准。随后，在合作研究中心寻求并获得了IRB批准，并在2013年夏季之前在所有机构进行了各种修订。2013 - 2015年，我们在NIH建立了一个PAH临床研究项目，该项目由具有心脏病学、肺部和重症监护专业知识的多学科医务人员以及在确保遵守临床方案同时保持最高临床护理标准方面具有丰富经验的监管和研究护理支持人员组成。 在2015-16报告期内，我们与NIH人类免疫学中心合作，进行了一项蛋白质组学分析研究，以确定螺内酯对PAH相关循环介质的影响。基于荧光珠的免疫测定使用Bio-ELISA法测定健康对照组（N=24）和PAH受试者（N=55）的细胞因子，将其分为3个诊断组（IPAH/遗传性PAH，n=26;结缔组织疾病相关性PAH，n=19;其他n=10;先天性心脏病相关性PAH，n=7;药物诱导的PAH，n=1;遗传性出血性毛细血管扩张相关PAH，n=1和门肺PAH，n=1）。使用多元线性回归模型调整PAH临床特征：年龄、性别、人种、NYHA/WHO分级（I/II与III/IV）、6分钟步行距离（6 MWD）、前列腺素类输注、当前使用1种PAH特异性治疗和螺内酯。与健康对照相比，PAH患者的不同样本中循环细胞因子水平升高。功能分类和6 MWD用测试的细胞因子的子集适度跟踪。目前的治疗似乎不会影响这种炎症特征，但混淆的临床合并症和相对较少的受试者数量可能阻碍了我们检测PAH治疗相关差异的能力。在2016年国际心肺移植学会第36届年会和科学会议（JHLT 35（4S）：S360，2016）上提交了题为“PAH中的血清细胞因子谱”的这项工作的摘要。 在2016-17报告期内，我们与人类免疫学中心（CHI）进行了合作。我们将为CHI提供样本，他们将处理这些样本用于炎症标志物和全血基因表达研究，以扩大我们对PAH受试者进行免疫表型分析的能力。我们还与NHLBI的移植基因组学实验室（LTG）合作，使用基于无细胞DNA的工具进行探索性研究，以评估PAH的发病机制和相关损伤。 本方案开放供入组。目前正在从多个地点收到推荐信。迄今为止（2017年8月），本研究已审查了203例潜在受试者的图表，47例受试者已入组。

Pulmonary arterial hypertension (WHO Group I) is a rare disorder associated with poor survival. Endothelial dysfunction resulting from 1) genetic susceptibility, and 2) a triggering stimulus that initiates pulmonary vascular injury, the two-hit hypothesis, appears to play a central role both in the pathogenesis and progression of PAH. Inflammation appears to drive this dysfunctional endothelial phenotype, propagating cycles of injury and repair in genetically susceptible patients with IPAH and DaPAH. However, despite mounting evidence of vascular inflammation in patients with PAH, detailed phenotypic studies are lacking on the temporal evolution of this process and its contribution to right ventricular (RV) and pulmonary vascular remodeling. In this protocol subjects are thoroughly characterized by echocardiogram, 6-minute walk, cardiopulmonary stress testing, pulmonary function testing, cardiac CT, advanced cardiac MRI techniques, gene expression profiling, and serum biomarkers. We hypothesize that a detailed characterization of these subjects in conjunction with a more rigorous profile of the temporal evolution of vascular inflammation in PAH and its impact on RV and pulmonary vascular function will add prognostic value to traditional measures of disease severity and suggest novel therapeutic targets for future research. The protocol was initially approved by the NHLBI IRB in October 2012. Subsequently IRB approval was sought and obtained at collaborating sites and various amendments were brought into alignment at all institutions by summer 2013. In 2013 -15 we established at the NIH a clinical research PAH program consisting of a multidisciplinary medical staff with expertise in cardiology, pulmonary, and critical care as well as a regulatory and research nursing support staff with extensive experience in assuring compliance with clinical protocols while maintaining the highest standards of clinical care. In 2015-16 reporting period, in collaboration with the Center of Human Immunology at the NIH, we conducted a proteomic profiling study in order to determine the effects of spironolactone on circulating mediators relevant to PAH. Fluorescent bead-based immunoassay (Bio-Plex) was used to measure cytokines in healthy controls (N=24) and PAH subjects (N=55) divided into 3 diagnostic groups (IPAH/Hereditary-PAH, n=26; Connective Tissue Disease Associated-PAH, n=19; and Other n=10 Congenital Heart Disease Associated-PAH, n=7; drug-induced PAH, n=1; hereditary hemorrhagic telangiectasia-associated PAH, n=1 and porto-pulmonary PAH, n=1). Multiple linear regression models were used to adjust for PAH clinical characteristics: Age, gender, race, NYHA/WHO classification (I/II versus III/IV), 6-minute walk distance (6MWD), prostanoid infusion, current use of 1 PAH-specific therapy, and spironolactone. Circulating cytokine levels were elevated across a diverse sample of PAH patients compared to healthy controls. Functional classification and 6MWD modestly tracked with a subset of the tested cytokines. Current therapies did not appear to influence this inflammatory signature, but confounding clinical comorbidities and the relatively small number of subjects may have hindered our ability to detect PAH-treatment related differences. An abstract from this work entitled "Serum Cytokine Profiling in PAH" was presented at the 2016 International Society for Heart and Lung Transplantation 36th Annual Meeting and Scientific Sessions (JHLT 35(4S):S360, 2016). During the 2016-17 reporting period we entered into a collaboration with the Center for Human Immunology (CHI). We will provide CHI with samples that they will process for markers of inflammation, and whole blood gene expression studies in order to expand our ability to immunophenotype subjects with PAH. We also entered into a collaboration with the Laboratory of Transplantation Genomics (LTG) of the NHLBI to do exploratory studies using cell-free DNA based tools to evaluate the pathogenesis of and injury related to PAH. The protocol is open for enrollment. Referrals are currently being received from multiple sites. To date (August 2017) 203 charts of potential subjects have been reviewed for this study and 47 subjects have been enrolled.