Mira E, Benazzo M, De Paoli F, Casasco A, Calligaro A
Clinica Otorinolaringoiatrica, Università di Pavia.
Acta Otorhinolaryngol Ital. 1997 Feb;17(1 Suppl 56):3-16.
The literature proving the presence of a surface tension lowering substance (STLS) on the lining layer of mammalian Eustachian tube (ET) is critically reviewed. A further review of the chemical studies on tubal washings based on chromatographic analysis methods (TLC and HPLC) is performed, and is concluded that ET epithelium is coated by a mixture of phospholipids, similar but not identical to the pulmonary surfactant and with similar but less powerful surface activity. In both cases, and with minor differences between the different mammalian species, phosphatidylcholine (PC), and in particular its disaturated fraction, dipalmitoilphosphatidylcholine (DPPC), is the predominating and the most active compound. ET surfactant is synthesized by ET epithelium and secreted in form of osmiophilic multilamellar bodies into the tubal lumen. The exact function of the ET surfactant is not fully understood: it may play an important role in ET physiology by facilitating the tubal opening to allow for aeration of the middle ear and adequate drainage or could act as a release agent, preventing solid-to-solid adhesion of the tubal walls and contrasting the adhesive action of the glycoproteins of the mucous blanket. On the other hand a phospholipidic surfactant seems to be produced by the mucosa of the other parts of the upper airways, i.e. nose and trachea. In this case a surface active agent could act in preventing the transudation of serum into the lumen, in enhancing the phagocytosis or in facilitating the mucociliary transport. Recent data on humans, suggesting that a relative deficiency or an alterated production of tubal surfactant could play a role in the pathogenesis of secretory otitis media (SOM) or middle ear effusion (MEE), are reviewed. Administration of exogenous surfactant or pharmacological stimulation of the production of tubal surfactant could improve ET function and be of value in some cases of SOM. Personal data, suggesting than ambroxol (a drug stimulating the production of pulmonary surfactant by the alveolar type II pneumocytes) exerts a similar activating effect on the tubotympanal secretory cells, are reported. These data support the results of clinical studies on the treatment of SOM with ambroxol.
对证明哺乳动物咽鼓管（ET）内衬层存在表面张力降低物质（STLS）的文献进行了批判性综述。基于色谱分析方法（薄层色谱法和高效液相色谱法）对咽鼓管冲洗液的化学研究进行了进一步综述，得出结论：ET上皮被磷脂混合物覆盖，与肺表面活性剂相似但不完全相同，且具有相似但较弱的表面活性。在这两种情况下，不同哺乳动物物种之间存在细微差异，磷脂酰胆碱（PC），尤其是其二饱和部分二棕榈酰磷脂酰胆碱（DPPC），是主要且最具活性的化合物。ET表面活性剂由ET上皮合成，并以嗜锇性多层小体的形式分泌到咽鼓管腔内。ET表面活性剂的确切功能尚未完全了解：它可能通过促进咽鼓管开放以允许中耳通气和充分引流，在ET生理学中发挥重要作用，或者可以作为一种释放剂，防止咽鼓管壁的固-固粘连并对抗粘液毯糖蛋白的粘附作用。另一方面，上呼吸道其他部位，即鼻子和气管的粘膜似乎也产生磷脂表面活性剂。在这种情况下，表面活性剂可以起到防止血清渗入管腔、增强吞噬作用或促进粘液纤毛运输的作用。综述了关于人类的最新数据，这些数据表明咽鼓管表面活性剂的相对缺乏或产生改变可能在分泌性中耳炎（SOM）或中耳积液（MEE）的发病机制中起作用。在某些SOM病例中，给予外源性表面活性剂或对咽鼓管表面活性剂的产生进行药理刺激可能会改善ET功能并具有价值。报告了个人数据，表明氨溴索（一种刺激肺泡II型上皮细胞产生肺表面活性剂的药物）对鼓室分泌细胞具有类似的激活作用。这些数据支持了用氨溴索治疗SOM的临床研究结果。
