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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, METHODS, RESULTS. Meshes: Administration, Inhalation, Androstadienes, Animals, Antigens, Asthma, Bronchi, Bronchoalveolar Lavage Fluid, Female, Fluticasone, Gene Expression Regulation, Glucocorticoids, Horse Diseases, Horses, Male, Muscle, Smooth, Myosin Heavy Chains, Protein Isoforms, Remission Induction, Smooth Muscle Myosins, Trachea.
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Do inhaled corticosteroids modulate the ( + ) insert smooth muscle myosin heavy chain in the equine asthmatic airways? Context: Overexpression of the (+)insert smooth muscle myosin heavy chain (SMMHC) isoform could contribute to airway bronchospasm by increasing the velocity of contraction. Whether the (+)insert isoform is present in the small airways and its expression is reversible in asthma are unknown. To determine the anatomical location and the expression kinetics of the (+)insert SMMHC isoform in airways of horses with heaves and to evaluate its modulation in response to disease status. We evaluated the (+)insert SMMHC isoform in the airways of horses with heaves during disease exacerbation and remission, and in controls. The expression kinetics of the SMMHC (+)insert was then assessed at multiple time points in two studies: first, in horses with heaves treated for a 1-year period with antigen avoidance alone, inhaled corticosteroids alone or both; second, in horses with heaves before and after a 30-day natural antigen exposure. Gene expression analysis was assessed by quantitative PCR and protein expression was confirmed by targeted mass spectrometry. The (+)insert SMMHC isoform was significantly increased in central and peripheral airways, but not in the trachea of heaves-affected horses in clinical exacerbation when compared horses with heaves in remission and controls. Both corticosteroid administration and antigen avoidance led to a significant reduction of the (+)insert expression in the airways. The (+)insert SMMHC isoform was not significantly increased in airways after 1 month of antigenic re-exposure.
assistant
The (+)insert SMMHC expression is increased throughout the bronchial tree in horses with heaves and reversible by corticosteroids administration and antigen avoidance. Final Decision: yes