Mitochondrial Antioxidant Therapy Fails to Improve Obese Asthma Outcomes.

BACKGROUND: Obesity is associated with poorly controlled asthma. One reason for this may be the increased mitochondrial oxidative stress in obese asthma. Indeed, targeting oxidative stress reduces airway reactivity in animal models. The purpose of this trial was to investigate the potential efficacy of the mitochondrial-targeted antioxidant MitoQuinone (MitoQ) for the treatment of poorly controlled asthma in people with obesity. METHODS: A twelve week, randomized, double-masked, placebo-controlled trial of 40 mg MitoQ versus placebo in adults with obesity and poorly controlled asthma was performed. The primary outcome was change in airway reactivity, with secondary outcomes of change in asthma control, quality of life, and lung function. RESULTS: Twenty participants were randomized to MitoQ, 18 to placebo. After 12 weeks, there was no difference in change in airway reactivity to methacholine (provocative dose producing a 20% decrease in FEV1) between the group assigned to MitoQ (median change= 0.0 μg [IQR -25.5 to 1.4]) or placebo (change = -0.8 μg [IQR -57 to 0.0]), p=0.81. There was no difference in the change in Asthma Control Test score (MitoQ 1 [IQR -1 to 2], placebo 1 [-2 to 2]), p=0.62, or Marks Asthma Quality of Life Score (MitoQ -0.08 [IQR -0.35 to 0.10], placebo -0.05 [-0.30 to 0.15]), p=0.80. CONCLUSION: MitoQ was well tolerated but did not improve airway reactivity, asthma control, or lung function. Targeting oxidative stress in people with obesity and poorly controlled asthma with MitoQ is unlikely to be efficacious for the treatment of asthma.