SABAs downregulate anti-inflammatory effects of inhaled corticosteroids as shown by higher bromotyrosine levels

Previous research suggests that short-acting beta2-agonists (SABAs) may downregulate the anti-inflammatory effects of inhaled corticosteroids, thereby increasing asthma morbidity.

3-bromotyrosine and 3,5-dibromotyrosine levels are markers of eosinophil activation. 3-Bromotyrosine levels correlate with eosinophil cationic protein levels. These modified tyrosine residues provide useful information about the inflammatory state of the airways.

In this study, levels of 3-bromotyrosine and 3,5-dibromotyrosine were measured in sputum during treatment with terbutaline, budesonide, and their combination in 28 patients with persistent asthma.

Treatment with budesonide lowered 3-bromotyrosine levels compared with placebo and terbutaline. Budesonide-terbutaline lowered 3,5-dibromotyrosine levels compared with placebo and terbutaline treatments.

3-bromotyrosine and 3,5-dibromotyrosine were significantly raised when terbutaline was added to budesonide treatment.

The authors concluded that 3-Bromotyrosine and 3,5-dibromotyrosine reflect treatment effects in asthma and support previous findings that SABAs impair the anti-inflammatory effects of inhaled corticosteroids.

Bromotyrosines in sputum proteins and treatment effects of terbutaline and budesonide in asthma. van Dalen CJ, Aldridge RE, Chan T, Senthilmohan R, Hancox RJ, Cowan JO, Taylor DR, Town GI, Kettle AJ. Ann Allergy Asthma Immunol. 2009 Oct;103(4):348-53.
Image source: Terbutaline. Wikipedia, public domain.

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