Prolonged methylprednisolone treatment suppresses systemic inflammation in patients with unresolving acute respiratory distress syndrome: evidence for inadequate endogenous glucocorticoid secretion and inflammation-induced immune cell resistance to glucocorticoids.

Abstract

Nuclear factor-kappaB (NF-kappaB) and glucocorticoid receptor-alpha (GR-alpha) have diametrically opposed functions in regulating inflammation. We investigated whether unresolving acute respiratory distress syndrome (ARDS) is associated with systemic inflammation- induced glucocorticoid resistance and whether prolonged methylprednisolone administration accelerates the suppression of systemic inflammatory indices and normalizes the sensitivity of the immune system to glucocorticoids. Patients enrolled into a randomized trial evaluating prolonged methylprednisolone administration in unresolving ARDS had serial plasma samples collected before and after randomization. In the plasma, we measured the concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukins (IL) IL-1beta and IL-6, adrenocorticotropic hormone (ACTH), and cortisol. The ability of patient plasma to influence the NF-kappaB and GR-signal transduction systems of normal peripheral blood leukocytes (PBL) was examined. Patients treated with methylprednisolone had progressive and sustained reductions of TNF-alpha, IL-1beta, IL-6, ACTH, and cortisol concentrations over time. Normal PBL exposed to plasma samples collected during methylprednisolone exhibited significant progressive increases in all aspects of GR-mediated activity and significant reductions in NF-kappaB DNA-binding and transcription of TNF-alpha and IL-1beta. These findings provide support for the presence of endogenous glucocorticoid inadequacy in the control of inflammation and systemic inflammation-induced peripheral glucocorticoid resistance in ARDS. Prolonged methylprednisolone administration accelerated the resolution of both systemic inflammation and peripheral acquired glucocorticoid resistance in ARDS.