Kostikas K, Koutsokera A, Papiris S, Gourgoulianis K I, Loukides S
Respiratory Medicine Department, University of Thessaly Medical School, Larissa, Greece.
Clin Exp Allergy. 2008 Apr;38(4):557-65. doi: 10.1111/j.1365-2222.2008.02940.x.
Exhaled breath condensate (EBC) analysis, a rather appealing and promising method, can be used to evaluate conveniently and non-invasively a wide range of molecules from the respiratory tract, and to understand better the pathways propagating airway inflammation. A large number of mediators of inflammation, including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, prostanoids, nitrogen oxides, peptides and cytokines, have been studied in EBC. Concentrations of such mediators have been shown to be related to the underlying asthma and its severity and to be modulated by therapeutic interventions. Despite the encouraging positive results to date, the introduction of EBC in everyday clinical practice requires the resolution of some methodological pitfalls, the standardization of EBC collection and finally the identification of a reliable biomarker that is reproducible has normal values and provides information regarding the underlying inflammatory process and the response to treatment. So far, none of the parameters studied in EBC fulfils the aforementioned requirements with one possible exception: pH. EBC pH is reproducible, has normal values, reflects a significant part of asthma pathophysiology and is measurable on-site with standardized methodology although some methodological aspects of measurement of pH in EBC (e.g. the effect of ambient CO(2), sample de-aeration, time for pH measurement) require further research. However, EBC pH has not been evaluated prospectively as a guide for treatment, in a manner similar to exhaled NO and sputum eosinophils. EBC represents a simple and totally non-invasive procedure that may contribute towards our understanding of asthma pathophysiology. Besides the evaluation of new biomarkers, the standardization of the already existing procedures is warranted for the introduction of EBC in clinical practice.
呼出气冷凝液（EBC）分析是一种颇具吸引力且前景广阔的方法，可用于便捷、无创地评估呼吸道中的多种分子，并更好地理解气道炎症的传播途径。大量炎症介质，包括腺苷、氨、过氧化氢、异前列腺素、白三烯、前列腺素、氮氧化物、肽和细胞因子，已在EBC中得到研究。这些介质的浓度已显示与潜在的哮喘及其严重程度相关，并可通过治疗干预进行调节。尽管迄今为止取得了令人鼓舞的积极成果，但要将EBC引入日常临床实践，需要解决一些方法学上的缺陷，实现EBC采集的标准化，最终确定一种可靠的生物标志物，该标志物具有可重复性、正常数值，并能提供有关潜在炎症过程和治疗反应的信息。到目前为止，EBC中研究的参数无一满足上述要求，可能pH值是个例外。EBC的pH值具有可重复性、有正常数值，反映了哮喘病理生理学的重要部分，并且可以使用标准化方法在现场进行测量，不过EBC中pH值测量的一些方法学方面（例如环境二氧化碳的影响、样品除气、pH值测量时间）需要进一步研究。然而，EBC的pH值尚未像呼出气一氧化氮和痰液嗜酸性粒细胞那样，以前瞻性方式作为治疗指导进行评估。EBC是一种简单且完全无创的程序，可能有助于我们理解哮喘病理生理学。除了评估新的生物标志物外，为了将EBC引入临床实践，对现有程序进行标准化也是必要的。
