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一种疾病- 随着咽气道尺寸的减小和咽气道可膨胀性的增加，我们 几乎不了解肥胖如何改变咽壁组织的机械特性， 这些变化。PI开发了一种新的MRI应用，具有组织运动跟踪（空间模块， 磁化或SPAMM <$）检查咽部区域变化之间的关系， 麻醉大鼠的气道大小和咽壁组织运动。利用这项创新技术，我们将 通过研究三组Zucker大鼠来确定肥胖对咽力学的影响， 不同程度的身体脂肪：瘦，肥胖，甚至更肥胖的大鼠喂食高脂肪饮食。我们的全球低- 肥胖通过气道狭窄、气道扩张和气道扩张损害咽部气道通畅， 可伸缩性，和不太有效的肌肉力学。目的1是确定1）咽气道是否 在年龄匹配的Zucker大鼠中，顺应性和闭合压力按以下顺序逐渐增加： <肥胖<脂肪增加的肥胖大鼠，以及2）这些发现是否与 咽脂肪目的2是确定咽壁组织运动的变化， 气道压力上升至诱导气道塌陷。将在应用期间使用SPAMM进行MRI 将低于大气压的压力施加到隔离的、密封的上气道，以测试1）气道塌陷是否主要是 由于咽前壁移位到气道中，以及2）对于给定的咽 区域，咽壁组织运动与气道压力下降之间的关系是进步的- 在年龄匹配的Zucker大鼠中，vively按以下顺序增加：瘦<肥胖<脂肪增加的肥胖大鼠。目的 图3是确定在电激活咽壁的过程中3组Zucker大鼠中的咽壁组织运动。 舌前肌和舌后肌。其结果将决定墙与墙之间的关系 在一定刺激强度范围内的组织位移和气道尺寸的增加逐渐减少 在年龄匹配的Zucker大鼠中的顺序为：瘦>肥胖>脂肪增加的肥胖。拟议的研究 将为肥胖如何影响咽力学提供新的信息，并增加我们的理解 为什么肥胖患者在睡眠中容易发生咽部气道塌陷。

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.