Enhancing the nitric oxide synthesis pathway in asthma: a plausible therapeutic approach?

Asthma is an inflammatory disease of the airways, caused by various allergens and characterized by airway hyper-responsiveness to stimuli. Inflammatory responses have two phases: an early asthma response in which acute inflammation mediators, such as histamine, induce bronchospasm; and a late asthma response involving more chronic and complex local inflammation. Nitric oxide (NO) is an endogenous mediator with bronchodilating and anti-inflammatory properties that is downregulated in asthma as a result of local inflammation. The augmented availability of NO in the lungs may represent a plausible approach for the treatment of asthma; however, the mechanisms leading to the decreased expression of this molecule have not been fully elucidated, and demonstration of the therapeutic effects of NO-enhancing compounds in asthma requires further research.