- 期刊
Role of Airway Smooth Muscle in Asthma: Contraction and Beyond
呼吸道平滑肌在氣喘的角色：收縮及其它功能
摘要
氣喘是一種慢性的炎症疾病，其特徵包含可逆性氣道阻塞、氣道過度反應與氣道發炎。呼吸道平滑肌可見於氣管至末梢細支氣管中，它被認爲是調節支氣管運動張力的重要組織。事實上，呼吸道平滑肌在正常肺部的生理相關機轉至今仍不清楚。在疾病狀況下如氣喘，呼吸道平滑肌的角色傳統上認爲是一種調節支氣管運動張力的被動組織。然而，更多的證據顯示呼吸道平滑肌也可以參與氣道發炎與重塑的進行。呼吸道平滑肌的收縮可調節氣管的內逕大小與氣道阻力，而這些變化可以受到細胞素與細胞外間質改變的影響，進而導致氣道過度反應，呼吸道平滑肌也可失學成一種免疫調節細胞，進而調控氣道發炎。除此之外，在氮喘患者，呼吸道平滑肌體只也明顯增加，這種現象代表著慢性發炎後的增生反應。這些證據顯示在疾病狀況下如氣喘，呼吸道平滑肌進顯著的表形變化。這篇綜論將探討呼吸道平滑肌的功能，說明它除了是一種被動的調節支氣管運動張力的組織外，也可以在氣喘中失學調節氣道發炎與重塑的角色。因此，進一步的研究與瞭解調控呼吸道平滑肌的細胞與分子機構，可提供未來治療氣 喘的新方向。
並列摘要
Asthma is a chronic inflammatory disease characterized by reversible airway obstruction, airway hyperresponsiveness, and airway inflammation. Airway smooth muscle (ASM), existing in the trachea and in the bronchial tree up to the terminal bronchioles, serves as an important structural effector tissue to regulate bronchomotor tone. However, the physiological relevance of ASM in healthy lungs is still unclear. In a disease status such as asthma, the role of ASM has been conventionally thought of as a passive tissue regulating bronchomotor tone. Nevertheless, growing evidence shows that ASM may also be involved in the development of airway inflammation and airway remodeling. The contraction of ASM regulates the airway luminal diameter and modulates airway resistance, which can be augmented by cytokines as well as extracellular matrix alterations leading to airway hyperresponsiveness. ASM may also serve as an immunomodulatory cell, regulating airway inflammation. In addition, ASM mass increases in asthma and may represent a proliferative response due to chronic inflammation. This evidence suggests that ASM undergoes marked phenotypic modulation in a disease status such as asthma. This review will present evidence that ASM, a passive contractile tissue, may also play an important role in the perpetuation of airway inflammation and the remodeling of the airway in asthma. Further investigation and understanding of the cellular and molecular mechanisms that regulate ASM functions may offer new therapeutic approaches in the treatment of asthma.