Abstract
BACKGROUND:
We and others have shown that the gamma tocopherol (γT) isoform of vitamin E has multiple anti-inflammatory and antioxidant actions and that γT supplementation reduces eosinophilic and endotoxin (LPS)-induced neutrophilic airway inflammation in animal models and healthy human volunteers.
OBJECTIVE:
To determine if γT supplementation reduces eosinophilic airway inflammation and acute neutrophilic response to inhaled LPS challenge in volunteers with asthma.
METHODS:
Participants with mild asthma were enrolled in a double-blinded, placebo controlled crossover study to assess the effect of 1200 mg of γT daily for 14 days on sputum eosinophils, mucins and cytokines. We also assessed the effect on acute inflammatory response to inhaled LPS challenge following γT treatment, focusing on changes in sputum neutrophilia, mucins and cytokines. Mucociliary clearance was measured using gamma scintigraphy.
RESULTS:
Fifteen subjects with mild asthma completed both arms of the study. Compared to placebo, γT notably reduced pre-LPS challenge sputum eosinophils and mucins, including MUC5AC, and reduced LPS-induced airway neutrophil recruitment 6 and 24-hours after challenge. Mucociliary clearance was slowed 4-hours post-challenge in the placebo group but not in the γT treatment group. Total sputum mucins (but not MUC5AC) were reduced at 24-hours post-challenge during γT treatment compared to placebo.
CONCLUSION:
γT supplementation for 14 days reduced inflammatory features of asthma, including sputum eosinophils and mucins, as well as acute airway response to inhaled LPS challenge when compared to placebo. Larger scale clinical trials are needed to assess the efficacy of γT supplements as a complementary or steroid-sparing treatment for asthma.