Predicting Heart Failure: Gene Profiling of Amplified RNA From Human Biopsies

描述（由申请人提供）：本R21申请将评估在冠状动脉搭桥（CABG）手术期间使用患者左心室（LV）活检扩增的RNA的可行性，以确定早期心脏重构的基因表达特征。作为首次尝试从症状前患者获得基因标记，这代表了一个新的研究领域，有可能加强与健康相关的研究。随着美国人口的老龄化，以及老年心肌梗死（MI）后患者生存率的提高，心力衰竭是一个巨大的公共卫生挑战。它是65岁以上住院患者的主要诊断：冠心病（CAD）导致心力衰竭的人群归因风险为62%，吸烟导致心力衰竭风险为17%，高血压导致心力衰竭风险为10%。一旦出现心脏病的症状，心脏的重塑就已经发生了。我们建议通过识别分子途径来改善治疗，这些分子途径是缺血性心脏病患者早期预防这种重塑过程的新治疗靶点。尽管微阵列的使用越来越多，但我们对无症状心功能障碍患者心脏转录组的早期变化知之甚少，这些变化可能导致心力衰竭。这在很大程度上是因为除了移植的衰竭心脏或心室辅助装置（VAD）手术外，没有足够的组织可用于RNA杂交到阵列。然而，当心功能障碍发展到完全衰竭时，复杂的早期、代偿性和晚期分子变化无法解开。我们提出了一种新的方法——从所有心衰阶段（症状前到严重阶段）的缺血性心脏病CABG患者的左室活检扩增RNA中获得基因表达谱，以区分无症状患者（ACC/AHA阶段a和B）、心功能受损患者（C期）和严重心力衰竭患者（D期）心衰的基因表达谱。我们的实验室现在成功地从活检大小的心脏标本中进行（两步）扩增ng量的RNA。我们还开发了一种新的临床数据收集工具，允许根据临床和生活方式变量对患者进行分层。具体目的有：(1)：测试鉴定缺血性心脏病患者心脏基因表达特征的可行性，作为心力衰竭严重程度增加的功能；(2)：检验确定可预防危险因素（吸烟）对缺血性心脏病高危患者转录组贡献的可行性，从而评估根据危险因素隔离患者的能力。这些研究将开辟新的领域，从无症状患者的纳克数量的RNA中确定基因谱的新应用，将有助于确定心脏病发展早期阶段的基因特征，并将构成迈向先发制人医学的第一步。这些初步研究将有助于识别症状前早期心力衰竭患者的基因表达特征。这将为我们实现先发制人或预防医学的目标迈出重要的第一步。通过这种方式，在未来，患者可以在重大疾病进展发生之前进行积极治疗。

DESCRIPTION (provided by applicant): This R21 application will assess the feasibility of using RNA amplified from left ventricular (LV) biopsies of patients during coronary artery bypass graft (CABG) surgery, in order to identify gene expression signatures of early cardiac remodeling. As a first attempt to obtain a gene signature from pre-symptomatic patients, this represents a novel area of investigation with the potential to enhance health-related research. With the aging of the US population, and improved survival of older patients after myocardial infarction (MI), heart failure is a huge public health challenge. It is the primary diagnosis for hospitalization of people over 65: The population-attributable risk for heart failure is 62% from coronary artery disease (CAD), 17% from smoking, and 10% from hypertension. Once individuals develop symptoms of heart disease, remodeling of the heart has already occurred. We propose to improve treatment by identifying molecular pathways that are novel therapeutic targets for early prevention of this remodeling process, in patients with ischemic heart disease. Despite increasing use of microarrays, we have little knowledge of early changes in the human cardiac transcriptome in asymptomatic patients with cardiac dysfunction that could lead to failure. This is in large part because insufficient tissue is available for RNA hybridization to arrays, except from explanted failing hearts or during ventricular assist device (VAD) surgery. However, when cardiac dysfunction has progressed to full blown failure, the complex early, compensatory and late molecular changes cannot be disentangled. We propose a novel approach - to obtain gene expression profiles from amplified RNA of LV biopsies from CABG patients with ischemic heart disease at all stages of heart failure - presymptomatic to severe - in order to distinguish gene expression profiles that foreshadow heart failure in asymptomatic patients (ACC/AHA stages A and B), in patients with impaired cardiac function (stage C) and patients with severe failure (stage D). Our laboratory now successfully performs (two-step) amplification of ng amounts of RNA from biopsy-sized cardiac specimens. We also developed a new clinical data collection tool to allow stratification of patients according to clinical and lifestyle variables. Specific Aims are (1): to test the feasibility of identifying cardiac gene expression signatures of patients with ischemic heart disease, as a function of increasing severity of heart failure; (2): to test the feasibility of identifying the contribution of a preventable risk factor (smoking) to the transcriptome of at risk patients with ischemic heart disease and thus assess the ability to segregate patients according to risk factors. These studies will break new ground by identifying novel applications for gene profiling from nanogram quantities of RNA from asymptomatic patients, will help identify gene signatures of early stages in cardiac disease development, and will constitute a first step towards pre- emptive medicine. These pilot studies will help identify gene expression signatures from pre-symptomatic patients with incipient heart failure. This will provide an important first step towards our goal of pre-emptive or preventative medicine. In this manner, in the future, patients can be aggressively treated before significant disease progression occurs.