Airway Eosinophil Activation by Anticholinergic Therapy

描述(由申请人提供)：虽然抗胆碱能药加用(-激动剂)已被证明对急性哮喘发作有益，但抗胆碱能药在治疗慢性稳定期哮喘方面的使用一直令人失望，而且似乎对其他药物的治疗没有什么帮助。我们最近做了一个令人惊讶的观察，在抗原攻击时用抗胆碱能阿托品治疗卵蛋白致敏的动物，显著增加了24小时后测量的迷走神经介导的高反应性(到那时阿托品已经消失)。当时的组织学检查显示嗜酸性粒细胞活化明显增加，这反映在细胞外嗜酸性粒细胞主要碱性蛋白的沉积增加。因此，抗胆碱能治疗使呼吸道疾病恶化。我们假设抗胆碱能药物可以阻断嗜酸性粒细胞上的M受体，而M受体通常起到限制嗜酸性粒细胞激活的作用。阻断嗜酸性粒细胞上的这些M受体会增加嗜酸性粒细胞的激活，加重呼吸道疾病。阐明乙酰胆碱对嗜酸性粒细胞功能的影响以及与之相关的特异性M受体将具有重要的临床意义。如果负责抑制嗜酸性粒细胞激活的特定M受体与负责平滑肌收缩的M3受体不同，那么选择性拮抗M3受体将允许在不增强嗜酸性粒细胞激活的情况下扩张支气管。或者，如果这是不可能的，通过抗胆碱能药激活嗜酸性粒细胞可能提供了将抗胆碱能药与旨在限制嗜酸性粒细胞激活的治疗相结合的理由，如CCR3拮抗剂。我们提出了两个特定的目标：特定的目标1：使用选择性拮抗剂来确定哪种M受体亚型与抗胆碱能药增强卵白蛋白诱导的迷走神经刺激的高反应性有关。具体目的2：证实豚鼠嗜酸性粒细胞上是否存在M受体，并将这种观察推广到人的嗜酸性粒细胞，并确定体外刺激嗜酸细胞M受体对嗜酸性粒细胞激活的影响。项目简介：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细胞，使哮喘恶化。在这个项目中，我们将找出这些药物如何使哮喘恶化，并在这样做的过程中，找出如何设计一种不会产生这些负面影响的治疗方法。

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.