脂肪在头颈部的沉积对阻塞性睡眠呼吸暂停影响的力学机制研究

Fat deposition in the head-and-neck region in obese persons is one of the leading causes of obstructive sleep apnea (OSA), but now the mechanism remains unclear. Although the prevalence of OSA is higher in obese people, not all of them are patients. It is of great significance for developing the personalized diagnosis and treatment methods to explore the mechanical mechanism of airway obstruction caused by obesity. We assume that fat deposition in the specific head-and-neck region will be a key reason for determining whether it can lead to OSA besides the effect of total fat increment. To confirm the hypothesis, this project will study and analyze the role of fat changes in each single region of the head and neck in the process of airway collapse and obstruction. To avoid the difficulties in human studies, we propose and design the fluid-structure interaction model for the real three-dimensional head-and-neck structure, based on the MRI images, to simulate and analyze the effects of individual and simultaneous volume changes of fat region on pharyngeal cavity morphology, flow state in the upper airway and respiratory function. The differences of the influence of the fat deposition among different groups were also analyzed. By comparing the results of animal fatten experiment with the results of numerical simulation, the reliability of the model for the fat growth is verified. Through the implementation of this project, we hope to reveal the puzzles surrounding the obesity as a cause of OSA.

肥胖者头颈部脂肪沉积是导致其发生阻塞性睡眠呼吸暂停（OSA）的主要原因之一，但其具体作用机制目前尚不清楚。虽然OSA在肥胖人群中患病率高，但并非所有肥胖者都会罹患OSA。探索肥胖导致气道阻塞的力学机制，对于发展个性化OSA诊断和治疗方法具有重要意义。我们提出如下假设：除了总量增加的影响之外，脂肪在头颈部特定部位的沉积是决定能否导致OSA的关键原因。为证实此假设，我们将研究和分析头颈部每个单一区域脂肪改变在气道塌陷和阻塞中所扮演的角色。为避开人体实验障碍，我们提出和设计基于MRI重建头颈部真实三维结构，用流固耦合模型模拟和分析各脂肪区域体积单独和同时变化时对咽腔形态、上气道内流动状态和呼吸功能的影响，并分析脂肪沉积影响在不同群体间的差异。通过将动物增肥实验结果与对其进行数值模拟的结果进行对比，验证数值模型用于脂肪增长研究的可靠性。希望通过本项目实施，可以解开在肥胖导致OSA问题上存在的谜团。

肥胖是阻塞性睡眠呼吸暂停（OSA）的主要风险因素之一，OSA的特点是在睡眠中反复发作的上呼吸道部分或完全塌陷。肥胖增加了头部和颈部的脂肪沉积，但它如何影响上气道形态的机械机制，以及为什么一些肥胖患者会出现阻塞性睡眠呼吸暂停，而另一些则不会，仍然不清楚。为了确定头颈部每个单一脂肪变化在改变上气道结构中的作用，并揭示肥胖引起的阻塞性睡眠呼吸暂停的机制，我们以体重指数正常的健康男性的MRI图像为参考模型，构建了一个解剖学上真实的三维头颈部结构。脂肪根据其在头颈部的位置被分为七个部分。利用这个独特的模型，我们模拟了由于增肥或减肥导致的任何单一脂肪或多个脂肪的变化而引起的上气道形态的变化。结果显示，咽旁脂肪、后颈部皮下脂肪和面部脂肪对上呼吸道的横截面积的影响最为明显。在相同的脂肪总量下，不同的脂肪分布导致了对上呼吸道形态的不同影响。本研究的重要发现显示，除了脂肪增加量外，脂肪沉积部位对影响气道塌陷也起着关键作用，并指出哪些类型的肥胖会使上气道狭窄，导致阻塞性睡眠呼吸暂停。