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

描述（由申请人提供）：该R21申请将评估在冠状动脉旁路移植术（CABG）手术期间使用从患者左心室（LV）活检扩增的RNA的可行性，以鉴定早期心脏重塑的基因表达特征。作为从症状前患者获得基因签名的第一次尝试，这代表了一个新的调查领域，有可能加强与健康相关的研究。随着美国人口的老龄化，以及心肌梗死（MI）后老年患者生存率的提高，心力衰竭是一个巨大的公共卫生挑战。这是65岁以上人群住院的主要诊断：心力衰竭的人群归因风险为62%来自冠状动脉疾病（CAD），17%来自吸烟，10%来自高血压。一旦个体出现心脏病的症状，心脏重塑已经发生。我们建议通过鉴定作为早期预防缺血性心脏病患者这种重塑过程的新治疗靶点的分子途径来改善治疗。尽管微阵列的使用越来越多，但我们对可能导致心力衰竭的无症状心功能不全患者的人类心脏转录组的早期变化知之甚少。这在很大程度上是因为没有足够的组织可用于RNA杂交到阵列，除了来自心脏衰竭或心室辅助装置（VAD）手术期间。然而，当心功能不全进展为完全衰竭时，复杂的早期、代偿性和晚期分子变化不能被解开。我们提出了一种新的方法-从缺血性心脏病CABG患者在心力衰竭的所有阶段（症状前到严重）的LV活检的扩增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（阶段C）和严重衰竭患者（阶段D）中预示心力衰竭的基因表达谱。我们的实验室现在成功地进行（两步）扩增ng量的RNA从活检大小的心脏标本。我们还开发了一种新的临床数据收集工具，可以根据临床和生活方式变量对患者进行分层。具体目的是（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函数;（2）：测试鉴定可预防的风险因素（吸烟）对缺血性心脏病风险患者转录组的贡献的可行性，从而评估根据风险因素分离患者的能力。这些研究将通过从无症状患者的纳克量RNA中确定基因谱的新应用而开辟新天地，将有助于确定心脏病发展早期阶段的基因特征，并将构成先发制人医学的第一步。这些试点研究将有助于识别早期心力衰竭症状前患者的基因表达特征。这将为我们实现先发制人或预防性医疗的目标迈出重要的第一步。通过这种方式，在未来，患者可以在发生重大疾病进展之前进行积极治疗。

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.