Gamma tocopherol-enriched supplement reduces sputum eosinophilia and endotoxin-induced sputum neutrophilia in volunteers with asthma

Background: We and others have shown that the gamma tocopherol (gamma T) isoform of vitamin E has multiple anti-inflammatory and antioxidant actions and that gamma T supplementation reduces eosinophilic and endotoxin (LPS)-induced neutrophilic airway inflammation in animal models and healthy human volunteers. Objective: We sought to determine whether gamma T 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 gamma T daily for 14 days on sputum eosinophils, mucins, and cytokines. We also assessed the effect on acute inflammatory response to inhaled LPS challenge following gamma T 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 with placebo, gamma T notably reduced pre-LPS challenge sputum eosinophils and mucins, including mucin 5AC and reduced LPS-induced airway neutrophil recruitment 6 and 24 hours after challenge. Mucociliary clearance was slowed 4 hours postchallenge in the placebo group but not in the gamma T treatment group. Total sputum mucins (but not mucin 5AC) were reduced at 24 hours postchallenge during gamma T treatment compared with placebo. Conclusions: When compared with placebo, gamma T supplementation for 14 days reduced inflammatory features of asthma, including sputum eosinophils and mucins, as well as acute airway response to inhaled LPS challenge. Larger scale clinical trials are needed to assess the efficacy of gamma T supplements as a complementary or steroid-sparing treatment for asthma.