Coronary Dysfunction, BK Channels, & Exercise in Heart Failure

描述(由申请人提供)：本提案的总体目的是评估大电导钙激活钾(BKCa)通道在射血分数(HFpEF)保留的心力衰竭患者冠状动脉血管功能障碍中的作用，并研究运动训练对这一过程的影响。我们的长期目标是确定HFpEF中冠状动脉血管功能障碍的分子机制，确定运动作为保存正常冠状动脉血管功能(CVF)的可行治疗方法的有效性。这项建议的具体目的是：1.)为确定SMC BKCa通道在HFpEF小型猪的表达/活性丧失是否是导致冠状动脉血管功能障碍的关键机制，研究SMC通道在HFpEF疾病进展中的作用，并确定调控这些过程的分子信号机制；目的：确定运动训练是否增加SMC BKCa通道的活性/表达，从而预防冠状动脉血管功能障碍和左心室功能和代谢关系的恶化。为了检验这些问题，我们将使用一种新的HFpEF微型猪模型，它被认为是临床相关的，也是关于人类CVF翻译影响的黄金标准。时间研究将被用来检验SMC BKCa通道是否先于HFpEF的发展，或者是疾病过程的表现。此外，我们将在15周的运动后进行实验，以验证以下假设：利用不同强度的训练方案，慢性运动保留了HFpEF中BKCa通道的活动/表达、冠状动脉血管功能以及左心室功能和代谢关系。将在BKCa通道激动剂(NS-1619，HenA)和拮抗剂(Penitrem A)的存在下，进行全面的体内(超声；冠脉血流；左心功能，即压力-容量环；代谢，即心肌VO2)和体外(离体微动脉，膜片钳)实验。使用综合方法，这些技术将使我们能够确定心力衰竭时CVF受损的机制是否是SMC BKCa通道表达/活性的丧失，检查该SMC通道在疾病进展中的作用，并确定运动作为一种治疗方法在保留HFpEF小型猪的正常冠状动脉血管和左室功能方面的有效性。

DESCRIPTION (provided by applicant): The general purpose of this proposal is to assess the contributions of smooth muscle cell (SMC) large conductance Ca2+-activated potassium (BKCa) channels to coronary vascular dysfunction in heart failure with preserved ejection fraction (HFpEF) and examine the effects of exercise training on this process. Our long-term objective is to identify the molecular mechanisms underlying coronary vascular dysfunction in HFpEF determine the efficacy of exercise as a viable treatment for preserving normal coronary vascular function (CVF). The specific aims of this proposal are: 1.) To determine if the loss of SMC BKCa channel expression/activity in miniature swine with HFpEF is a key mechanism underlying coronary vascular dysfunction, examine the role of this SMC channel in the disease progression of HFpEF, and identify molecular signaling mechanisms regulating these processes; and 2.) To determine if exercise training increases SMC BKCa channel activity/expression thus preventing coronary vascular dysfunction and deterioration of LV functional and metabolic relationships in miniature swine with HFpEF. To examine these issues, we will use a novel miniature swine model of HFpEF, which is considered both clinically relevant and a gold standard for translational impact regarding CVF in humans. Temporal studies will be used to test whether SMC BKCa channels precede the development of HFpEF or are a manifestation of the disease process. Further, we will perform experiments following 15 weeks of exercise to test the hypothesis that chronic exercise preserves BKCa channel activity/expression, coronary vascular function, and LV functional and metabolic relationships in HFpEF utilizing training protocols of differing intensity. Comprehensive in vivo (Ultrasound; Coronary Blood Flow; LV function, i.e. Pressure-Volume loops; metabolic, i.e. Myocardial VO2) and in vitro (isolated arteriole, patch-clamp) experiments will be performed in the presence of BKCa channel agonists (NS-1619, HENA) and antagonists (Penitrem A). Using an integrated approach, these techniques will allow us to determine if the mechanism underlying impaired CVF in HF is the loss of SMC BKCa channel expression/activity, examine the role of this SMC channel in disease progression, and determine the effectiveness of exercise as a treatment for preserving normal coronary vascular and LV function in miniature swine with HFpEF.