Airway Eosinophil Activation by Anticholinergic Therapy

描述（由申请人提供）：虽然在β-受体激动剂中加入抗胆碱能药物已被证明对急性哮喘发作有益，但在慢性稳定型哮喘的治疗中使用抗胆碱能药物令人失望，似乎对其他药物的治疗作用不大。我们最近发现，在抗原激发时用抗胆碱能阿托品治疗卵清蛋白致敏动物，24小时后（此时阿托品已消失）测量的迷走神经介导的高反应性显著增加。此时的组织学检查显示嗜酸性粒细胞活化显著增加，如嗜酸性粒细胞主要碱性蛋白的细胞外沉积增加所反映的。因此，抗胆碱能药物治疗加重了气道疾病。我们假设抗胆碱能药物阻断了嗜酸性粒细胞上的毒蕈碱受体，而这种受体通常起着限制嗜酸性粒细胞活化的作用。阻断嗜酸性粒细胞上的这些毒蕈碱受体会增加嗜酸性粒细胞的活化和气道疾病。描述乙酰胆碱对嗜酸性粒细胞功能的影响以及负责的特异性毒蕈碱受体将具有重大的临床意义。如果负责抑制嗜酸性粒细胞活化的特异性毒蕈碱受体与M3受体（负责平滑肌收缩）不同，则M3受体的选择性拮抗作用将允许支气管扩张而不增强嗜酸性粒细胞活化。或者，如果这是不可能的，激活嗜酸性粒细胞的抗胆碱能药物可能提供了一个理由，抗胆碱能药物与治疗相结合，旨在限制嗜酸性粒细胞的激活，如CCR 3拮抗剂。我们提出两个具体目标：具体目标1：使用选择性拮抗剂来确定哪个毒蕈碱受体亚型负责抗胆碱能药物增强卵清蛋白诱导的对迷走神经刺激的高反应性的能力。具体目标二：确认豚鼠嗜酸性粒细胞上存在毒蕈碱受体，将这些观察结果扩展至人嗜酸性粒细胞，并确定刺激嗜酸性粒细胞毒蕈碱受体对体外嗜酸性粒细胞活化的影响。项目叙述：阻断肺部神经释放物质的药物用于治疗哮喘。我们发现这些药物可能会激活白色血细胞，使哮喘恶化。在这个项目中，我们将找出这些药物是如何使哮喘恶化的，并在这样做的过程中，找出如何设计一种治疗方法，不会有这些负面影响。

DESCRIPTION (provided by applicant): While the addition of anticholinergics to (-agonists has been shown to be beneficial in acute asthma attacks, the use of anticholinergics in the management of chronic stable asthma has been disappointing, and seems to add little to treatment with other agents. We have recently made the surprising observation that treating ovalbumin sensitized animals with the anticholinergic atropine at the time of antigen challenge markedly increases vagally mediated hyperreactivity measured 24 hours later (by which time the atropine has worn off). Histological examination at that time shows markedly increased eosinophil activation, as reflected in increased extracellular deposition of eosinophil major basic protein. Thus the anticholinergic treatment made the airway disease worse. We hypothesize that anticholinergic medications block muscarinic receptors on eosinophils that normally function to limit eosinophil activation. Blocking these muscarinic receptors on the eosinophils increases eosinophil activation and worsens airway disease. Delineating the effects of acetylcholine on eosinophil function as well as the specific muscarinic receptor responsible will have substantial clinical implications. If the specific muscarinic receptor responsible for inhibiting eosinophil activation is different from the M3 receptor (which is responsible for smooth muscle contraction), then selective antagonism of the M3 receptor would allow bronchodilitation without potentiating eosinophil activation. Alternatively, if this is not possible, activation of eosinophils by anticholinergics might provide a rationale for combining anticholinergics with treatments aimed at limiting eosinophil activation, such as CCR3 antagonists. We propose two specific aims: Specific Aim 1: To use selective antagonists to determine which subtype of muscarinic receptor is responsible for the ability of anticholinergics to potentiate ovalbumin induced hyperreactivity to vagal stimulation. Specific Aim 2: To confirm the presence of muscarinic receptors on guinea pig eosinophils, to extend these observations to human eosinophils, and to determine the effects of stimulation of eosinophil muscarinic receptors on eosinophil activation in vitro. PROJECT NARRATIVE: Drugs that block substances released by nerves in the lungs are used to treat asthma. We have found that these drugs may activate white blood cells to make the asthma worse. In this project, we will find out how these drugs are making the asthma worse and, in so doing, find out how to design a treatment that won't have these negative effects.