Sacco Oliviero, Silvestri Michela, Sabatini Federica, Sale Rosa, Defilippi Anna-Carla, Rossi Giovanni A
Pulmonary Division, G Gaslini Institute, 16148 Genoa, Italy.
Paediatr Respir Rev. 2004;5 Suppl A:S35-40. doi: 10.1016/s1526-0542(04)90008-5.
Extensive lesions and changes in the architecture of the airway walls are commonly described in patients with respiratory infections, asthma, chronic bronchitis and interstitial lung diseases. Current knowledge identifies in airway epithelial cells and in fibroblasts the two cell types mainly involved in tissue repair after injury. During inflammatory respiratory disorders, extensive injury of airway epithelium may occur, with shedding of a large sheet of damaged cells in the bronchial and alveolar lumen but also with activation of the surviving epithelial cells and of the underlying fibroblasts. Indeed, besides acting as a physical and functional barrier to external agents, the epithelial surface of the bronchi has the capability to modulate the repair processes through the secretion of extracellular matrix proteins and the interaction with interstitial fibroblasts. Besides releasing pro-inflammatory cytokines and chemokines, the surviving epithelial cells and the underlying fibroblasts secrete factors contributing to airway repair, including the formation of the provisional extracellular matrix. This is indeed the substrate to which the epithelial cells at the edge of the lesion can attach to migrate in order to reconstitute the surface layer. In these processes airway epithelial cells receive the support of bronchial wall fibroblasts which actively release cytokines stimulating epithelial cell functions.
在患有呼吸道感染、哮喘、慢性支气管炎和间质性肺病的患者中，气道壁广泛的病变和结构改变较为常见。目前的认识表明，气道上皮细胞和成纤维细胞是损伤后组织修复中主要涉及的两种细胞类型。在炎症性呼吸系统疾病期间，气道上皮可能会发生广泛损伤，支气管和肺泡腔内会有一大片受损细胞脱落，同时存活的上皮细胞和其下方的成纤维细胞也会被激活。事实上，除了作为对外界因素的物理和功能屏障外，支气管的上皮表面还能够通过分泌细胞外基质蛋白以及与间质成纤维细胞相互作用来调节修复过程。除了释放促炎细胞因子和趋化因子外，存活的上皮细胞和其下方的成纤维细胞还分泌有助于气道修复的因子，包括形成临时细胞外基质。这确实是病变边缘的上皮细胞能够附着并迁移以重建表层的底物。在这些过程中，气道上皮细胞得到支气管壁成纤维细胞的支持，后者会积极释放刺激上皮细胞功能的细胞因子。
