No abstract

Participants randomized to cardiovascular exercise experienced improvements in influenza seroprotection throughout the entire influenza season, whereas those in the balance and flexibility intervention did not. Although there were no differences in reported respiratory tract infections, the exercise group exhibited reduced overall illness severity and sleep disturbance. These data support the hypothesis that regular endurance exercise improves influenza vaccine responses.

No abstract

We have reported previously that moderate intensity aerobic exercise training attenuates airway inflammation in a murine asthma model. Recent studies implicate regulatory T (Treg) cells in decreasing asthma-related airway inflammation; as such, the current study examined the effect of exercise on Treg cell function in a murine asthma model. Mice were sensitized with ovalbumin (OVA) prior to the start of exercise training at a moderate intensity 3× / week for 4 wks; exercise was performed as treadmill running (13.5 m/min, 0% grade). Mice were OVA challenged repeatedly throughout the exercise protocol. At protocol completion, mice were analyzed for changes in the number and suppressive function of CD4+CD25+Foxp3+ cells isolated from lungs, mediastinal lymph nodes, and spleens. Results show that exercise increased significantly the number of Foxp3+ cells within the lungs and mediastinal lymph nodes, but not the spleens, of OVA-treated mice as compared with sedentary controls. Exercise also enhanced the suppression function of CD4+CD25+Foxp3+ Treg cells derived from OVA-treated mice as compared with sedentary controls. Specifically, Treg cells from exercised, OVA-treated mice more effectively suppressed CD4+CD25− cell proliferation and Th2 cytokine production in vitro. Enhanced suppression was associated with increased protein levels of TGF-β and lesser amounts of IL-10 and IL-17; however, blocking TGF-β had no effect on suppressive functions. These data demonstrate that exercise-mediated increases in Treg cell function may play a role in the attenuation of airway inflammation. Further, these results indicate that moderate intensity aerobic exercise training may alter the Treg cell function within the asthmatic airway.

β(2)-Adrenoceptor (β2AR) agonists are the most effective class of bronchodilators and a mainstay of asthma management. The first potent β2AR agonist discovered and widely used in reversing the airway constriction associated with asthma exacerbation was the endogenous activator of the β2AR, epinephrine. In this study, we demonstrate that activation of the β2AR by epinephrine is paradoxically required for development of the asthma phenotype. In an antigen-driven model, mice sensitized and challenged with ovalbumin showed marked elevations in three cardinal features of the asthma phenotype: inflammatory cells in their bronchoalveolar lavage fluid, mucin over production, and airway hyperresponsiveness. However, genetic depletion of epinephrine using mice lacking the enzyme to synthesize epinephrine, phenylethanolamine N-methyltransferase, or mice that had undergone pharmacological sympathectomy with reserpine to deplete epinephrine, had complete attenuation of these three cardinal features of the asthma phenotype. Furthermore, administration of the long-acting β2AR agonist, formoterol, a drug currently used in asthma treatment, to phenylethanolamine N-methyltransferase-null mice restored the asthma phenotype. We conclude that β2AR agonist-induced activation is needed for pathogenesis of the asthma phenotype. These findings also rule out constitutive signaling by the β2AR as sufficient to drive the asthma phenotype, and may help explain why chronic administration of β2AR agonists, such as formoterol, have been associated with adverse outcomes in asthma. These data further support the hypothesis that chronic asthma management may be better served by treatment with certain "β-blockers."