Is endothelin-1 a mediator in asthma?

There is a growing understanding of the effects and potential pathophysiological role of the ETs in asthma and several of the criteria required to strongly implicate ET-1 as a mediator in this disease have been fulfilled. However, some of the information is preliminary, equivocal and requires confirmation. Furthermore, the most important and most difficult criteria, the clinical testing of potent and selective ET receptor antagonists in these diseases has not been conducted and will probably not be completed for several years. A critical area of research continues to be the elucidation and classification of the ET receptor subtypes mediating the diverse effects of ET-1 in the lung. The unequivocal determination of the pathophysiological role of the ETs in asthma awaits the results of clinical trials with appropriate compounds. Only after these results will we know whether ET-1 has fulfilled its promise as a key player in lung pathophysiology, rather than being added to the list of purported important mediators with unfulfilled expectations.