Obesity Effects on Pharyngeal Airway Mechanics by MRI

肥胖是阻塞性睡眠呼吸暂停最重要的预测因素。尽管我们知道肥胖是有关联的-- 随着咽部呼吸道大小的减少和咽部呼吸道塌陷性的增加，我们有 几乎不了解肥胖是如何改变咽壁组织的机械性能来影响 这些变化。PI开发了具有组织运动跟踪(空间模块)的MRI的新应用 磁化作用，或Spamm)，以检查咽部局部变化之间的关系 麻醉大鼠的呼吸道大小和咽壁组织运动。使用这项创新技术，我们将 通过对三组Zucker大鼠的研究，确定肥胖对咽力学的影响 不同程度的身体脂肪：精瘦、肥胖、甚至更肥胖的大鼠喂食高脂肪食物。我们的全球次元- 论点是肥胖通过气道狭窄、气道增加而损害咽部呼吸道通畅 可崩解性，以及效率较低的肌肉力学。目的1)确定1)咽部呼吸道 在年龄匹配的Zucker大鼠中，依从性和关闭压力按以下顺序逐渐增加：瘦身 肥胖和脂肪增加的肥胖大鼠，以及2)这些发现是否与 咽部脂肪。目标2是确定咽壁组织运动的变化 呼吸道压力上升到引起的呼吸道塌陷。在应用期间，将执行带有Spamm的MRI 对隔离、封闭的上呼吸道进行亚大气压试验1)是否主要以呼吸道塌陷为主 由于咽前壁移位进入呼吸道，以及2)对于给定的咽部 咽壁组织运动与呼吸道压力降低的关系正在研究中。 在年龄匹配的Zucker大鼠中，活跃度按以下顺序增加：瘦肉型肥胖大鼠。目标 3测定3组Zucker大鼠在电刺激时咽壁组织的运动。 舌头突出和伸缩肌。结果将决定墙与墙之间的关系 在一定刺激强度范围内，组织移位和气道大小增加逐渐减少 在年龄匹配的Zucker大鼠中，顺序为：瘦身肥胖和肥胖加重肥胖。建议进行的研究 将提供有关肥胖如何影响咽部力学的新信息，并增加我们对 为什么肥胖患者在睡眠时容易出现咽部呼吸道塌陷。

Obesity is the most important predictor for obstructive sleep apnea. Although we know that obesity is assoc- iated with a decrease in pharyngeal airway size and an increase in pharyngeal airway collapsibility, we have almost no understanding of how obesity alters the mechanical properties of pharyngeal wall tissues to effect these changes. The PI has developed a novel application of MRI with tissue motion tracking (spatial modul- ation of magnetization, or SPAMM¿) to examine the relationships between regional changes in pharyngeal airway size and pharyngeal wall tissue motion in anesthetized rats. Using this innovative technique, we will determine the effects of obesity on pharyngeal mechanics by studying three groups of Zucker rats with different degrees of body fat: lean, obese, and even more obese rats fed a high-fat diet. Our global hypo- thesis is that obesity compromises pharyngeal airway patency through airway narrowing, increased airway collapsibility, and less effective muscle mechanics. Aim 1 is to determine 1) whether pharyngeal airway compliance and closing pressure progressively increase across age-matched Zucker rats in the order: lean < obese < fat-augmented obese rats, and 2) whether these findings are directly related to the amount of pharyngeal fat. Aim 2 is to determine changes in pharyngeal wall tissue motion for increasingly negative airway pressure up to induced airway collapse. MRI with SPAMM will be performed during application of subatmospheric pressure to the isolated, sealed upper aiway to test 1) whether airway collapse is primarily due to displacement of the anterior pharyngeal wall into the airway, and 2) whether, for a given pharyngeal region, the relationship between pharyngeal wall tissue motion and airway pressure decrements is progress- ively increased across age-matched Zucker rats in the order: lean < obese < fat-augmented obese rats. Aim 3 is to determine pharyngeal wall tissue motion in the 3 groups of Zucker rats during electrical activation of tongue protrudor and retractor muscles. The results will determine whether the relationship between wall tissue displacement and increase in airway size over a range of stimulus intensities is progressively reduced across age-matched Zucker rats in the order: lean > obese > fat augmented obese. The proposed studies will provide new information on how obesity affects pharyngeal mechanics and increase our understanding of why obese patients are predisposed to pharyngeal airway collapse during sleep.