Myocyte-specific nanoplatform-enabling photodynamic cardiac ablation

肌细胞特异性纳米平台实现光动力心脏消融

基本信息

批准号：
8383284
负责人：
Jerome Kalifa
金额：
$ 19.44万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-16 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8383284
关键词：
Ablation Action Potentials Adipocytes Adult Affect American Animals Antibodies Area Arrhythmia Binding Caliber Cancerous Cardiac Cardiac ablation Cell Death Cells Chest Chest wall structure Coculture Techniques Coronary Development Dyes Energy Transfer Epicardium Event Excision Fibroblasts Fibrosis Fistula Frequencies Generations Heart Hemorrhage Histology Inflammation Inflammatory Inflammatory Infiltrate Injury Investigation Lasers Left Light Lighting Maps Methodology Modality Modeling Motion Muscle Cells Myocardial Myofibroblast Nature Necrosis Neurons Optics Oxygen Peptides Perforation Perfusion Pharmaceutical Preparations Photochemotherapy Photosensitizing Agents Preparation Pulmonary veins Radio Radiofrequency Interstitial Ablation Rattus Reaction Reactive Oxygen Species Refractory Regional Perfusion Safety Sampling Spasm Staining method Stains Stenosis Subgroup Surgical sutures Techniques Testing Tissues Toxic effect Ventricular base blebbistatin experience in vivo innovation research study voltage

项目摘要

DESCRIPTION (provided by applicant): Regional myocardial ablation enabled by radio-frequency or other energies is currently the main treatment modality for drug-refractory arrhythmias. However, the highly unspecific nature of current ablation methodologies is responsible for unnecessary damage to cardiac or peri-cardiac tissue, thus severely hampering ablation safety and efficacy. Photodynamic therapy (PDT) has been extensively studied for treating cancerous cells. In PDT, after activation by light, photosensitizer agents transfer energy to oxygen molecules and generate reactive oxygen species which induce cell death exquisitely confined to photosensitized cells, while adjacent non photosensitized cells are spared. In specific aim 1, we will use a recently developed cardiac targeting peptide (CTP) that binds to myocytes while it does not attach to other cardiac cells. In preliminary experiments, we have demonstrated that CTP-PDT-NPs delivered in co-cultures of adult rat ventricular myocytes and fibroblasts, led to myocytes-specific damage after laser illumination. Thus, we hypothesize that in isolated Langendorff-perfused rat hearts, CTP- conjugated-PDT-NPs (CTP-PDT-NPs) will enable obtaining myocyte-specific ablation while fibroblasts will be spared. With optical mapping techniques, we will determine how myocyte-specific ablation after illumination of a ventricular region with a 671 nm Laser, compares with non-specific ablation in terms of impulse propagation during pacing and during reentry. In specific aim 2, we will determine whether myocyte-specific ablation with PDT-NPs could be implemented in the whole animal. In this aim, CTP-PDT-NPs will be injected intravenously in an anesthetized rat open chest model. After 10-30 minutes, we will illuminate a small region of the ventricular epicardium and subsequently, the heart will be removed and an immunohistological investigation with myocyte and fibroblast cell-specific antibody staining will be conducted. This will enable to assess the degree of damage induced to myocytes, and the extent to which fibroblasts and other non-myocyte cells were spared. Also, in a subgroup of rats, the chest wall will be sutured after ablation and animals will be followed-up for one month. Then, after heart removal, histological testing will be conducted to detect inflammatory infiltrates and fibrosis and assess fibroblast proliferation. Results will be compared with those of rats that underwent radiofrequency ablation or were sham operated. In this aim, we hypothesize that myocyte-specific ablation in vivo will associate with a decreased inflammatory reaction and fibroblast differentiation into myofibroblasts, as well as a dampened fibroblast proliferation and fibrosis formation. PUBLIC HEALTH RELEVANCE: Regional myocardial ablation enabled by radio-frequency or other energies is currently the main treatment modality for drug-refractory arrhythmias which are cardiac conditions affecting several million Americans each year. However, the highly unspecific nature of current ablation methodologies is responsible for unnecessary damage to cardiac or peri-cardiac tissue, thus severely hampering ablation safety and efficacy. Here, we propose to investigate an innovative ablation approach that will enable targeting specifically those cardiac cells involved in the initiation and perpetuation of arrhythmic conditions. Thus, this project coul pave the way for developing safer and more efficient therapies for cardiac arrhythmias.

描述（由申请人提供）：当前，通过射频或其他能量来实现区域心肌消融，目前是药物难治性心律不齐的主要治疗方式。但是，当前消融方法的高度非特异性性质是对心脏或心脏组织组织的不必要损害，从而严重阻碍了消融安全性和有效性。光动力疗法（PDT）已被广泛研究用于治疗癌细胞。在PDT中，光线激活后，光敏剂转移能量对氧分子并产生活性氧，这些氧气诱导细胞死亡精确地局限于光敏细胞，而相邻的非光敏细胞则被保留下来。在特定的目标1中，我们将使用最近开发的心脏靶向肽（CTP），该肽（CTP）与肌细胞结合，而它不连接到其他心脏细胞。在初步实验中，我们证明了在成年大鼠心室心肌细胞和成纤维细胞共培养中传递的CTP-PDT-NP，导致激光照明后特定于肌细胞特异性损伤。因此，我们假设在孤立的langendorff垂直的大鼠心脏中，CTP-共轭PDT-NP（CTP-PDT-NPS）将能够获得肌细胞特异性消融，而成纤维细胞将被保留。借助光学映射技术，我们将确定用671 nm激光照明心室区域后的肌细胞特异性消融，与在起搏期间和重新进入过程中的脉冲繁殖方面相比，与非特异性消融相比。在特定的目标2中，我们将确定是否可以在整个动物中实施用PDT-NP的肌细胞特异性消融。在此目标中，CTP-PDT-NP将静脉注射在麻醉大鼠开放式胸部模型中。 10-30分钟后，我们将照亮心室心外膜的一小部分区域，随后将去除心脏，并将对心肌细胞和成纤维细胞特异性抗体染色进行免疫组织学研究。这将能够评估诱导肌细胞的损伤程度，以及育纤维细胞和其他非肌细胞细胞的程度。同样，在大鼠亚组中，将在消融后将缝合胸壁跟进一个月。然后，在去除心脏后，将进行组织学检测以检测炎症性浸润和纤维化并评估成纤维细胞增殖。结果将与经历射频消融或假手术的大鼠的结果进行比较。在此目标中，我们假设体内肌细胞特异性消融将与炎症反应降低和成纤维细胞分化为肌纤维细胞，以及衰减的成纤维细胞增殖和纤维化的形成。公共卫生相关性：通过射频或其他能量来实现的区域心肌消融，目前是药物难治性心律不齐的主要治疗方式，这是每年影响数百万美国人的心脏病。但是，当前消融方法的高度非特异性性质是对心脏或心脏组织组织的不必要损害，从而严重阻碍了消融安全性和有效性。在这里，我们建议研究一种创新的消融方法，该方法将使特定靶向那些涉及心律不齐条件的涉及的心脏细胞。因此，该项目为为心律不齐而开发更安全，更有效的疗法铺平了道路。