RT Journal Article SR Electronic T1 The immune response to resistive breathing JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1033 OP 1043 DO 10.1183/09031936.04.00067904 VO 24 IS 6 A1 T. Vassilakopoulos A1 C. Roussos A1 S. Zakynthinos YR 2004 UL http://erj.ersjournals.com/content/24/6/1033.abstract AB Resistive breathing is an “immune challenge” for the body, initiating an inflammatory response consisting of an elevation of plasma cytokines, and the recruitment and activation of lymphocyte subpopulations. These cytokines do not originate from monocytes, but are, instead, produced within the diaphragm, secondary to the increased muscle activation. Oxidative stress is a major stimulus for the cytokine induction, secondary to resistive breathing. The production of cytokines within the diaphragm may be mediating the diaphragm muscle fibre injury that occurs with strenuous contractions, or contributing towards the expected repair process. These cytokines may also compromise diaphragmatic contractility or contribute towards the development of muscle cachexia. They may also have systemic effects, mobilising glucose from the liver and free fatty acid from the adipose tissue to the strenuously working respiratory muscles. At the same time, they stimulate the hypothalamic-pituitary-adrenal axis, leading to production of adrenocorticotropin and β-endorphins. The adrenocorticotropin response may represent an attempt of the organism to reduce the injury occurring in the respiratory muscles via the production of glucocorticoids and the induction of the acute phase-response proteins. The β-endorphin response would decrease the activation of the respiratory muscles and change the pattern of breathing, which becomes more rapid and shallow, possibly in an attempt to reduce and/or prevent further injury to the respiratory muscles.