Septic serum induces glucocorticoid resistance and modifies the expression of glucocorticoid isoforms receptors: a prospective cohort study and in vitro experimental assay.

BACKGROUND: A protective role for glucocorticoid therapy in animal models of sepsis was shown many decades ago. In human sepsis, there is new interest in glucocorticoid therapy at a physiological dose after reports of improved response to vasopressor drugs and decreased mortality in a selected group of patients. However, other reports have not confirmed these results. Cellular glucocorticoid resistance could explain a possible cause of that. To evaluate this hypothesis, we evaluated the expression of glucocorticoid receptor beta, the dominant negative isoform of glucocorticoid receptor, in peripheral mononuclear cells of septic patients and the effect of serum septic patients over glucocorticoid receptor expression and glucocorticoid sensitivity in immune cells culture. METHODS: A prospective cohort study and an in vitro experimental study with matched controls were developed. Nine patients with septic shock and nine healthy controls were prospectively enrolled. Mononuclear cells and serum samples were obtained from the patients with sepsis on admission to the Intensive Care Unit and on the day of discharge from hospital, and from healthy volunteers matched by age and sex with the patients. Glucocorticoid receptor alpha and beta expression from patients and from immune cell lines cultured in the presence of serum from septic patients were studied by western blot. Glucocorticoid sensitivity was studied in control mononuclear cells cultured in the presence of serum from normal or septic patients. A statistical analysis was performed using a Mann-Whitney test for non-parametric data and analysis of variance for multiple comparison; P<0.05 was considered significant. RESULTS: The patients' glucocorticoid receptor beta expression was significantly higher on admission than on discharge, whereas the alpha receptor was not significantly different. In vitro, septic serum induced increased expression of both receptors in T and B cells in culture, with a greater effect on receptor beta than the control serum. Septic serum induced glucocorticoid resistance in control mononuclear cells. CONCLUSION: There is a transient increased expression of glucocorticoid receptor beta in mononuclear cells from septic patients. Serum from septic patients induces cell glucocorticoid resistance in vitro. Our findings support a possible cell glucocorticoid resistance in sepsis.

Effects of methotrexate on the expression of the translational isoforms of glucocorticoid receptors α and ß: correlation with methotrexate efficacy in rheumatoid arthritis patients.

OBJECTIVES: To test the effect of MTX on the expression of glucocorticoid receptor (GR) α and ß isoforms AB, C and D in peripheral blood mononuclear cells (PBMCs) in culture, from newly diagnosed RA patients and to evaluate whether the test results correlate with patients' subsequent response to MTX treatment. METHODS: Twenty patients with early active RA were enrolled. Patients who had previously received any DMARD or cytotoxic agent, or who had received CSs in the 6 months before enrolment were excluded. PBMCs from all patients were obtained and cultured in the presence and absence of MTX (10(-4), 10(-6) and 10(-8) M). The expression of GR isoforms was evaluated by western blot. After blood samples were taken, patients entered a 24-week study receiving MTX, diclofenac and prednisone (10 mg/day). At Week 24, the ACR core set of disease activity measures was calculated and a correlation between the MTX effect on patients' PBMC GR expression in vitro and the ACR response was evaluated. RESULTS: MTX 10(-6) M in the culture medium induced the expression of the PBMC isoform AB of GRα (P = 0.009). Other GR isoforms were unaffected. The magnitude of the induced expression correlated with the ACR response to treatment at Week 24 of therapy (r = 0.92, P = 0.00003). CONCLUSION: MTX in vitro induces greater expression of GRαAB isoform in PBMC from RA patients who later respond to MTX treatment than in non-responding patients. This may have clinical applications for predicting MTX efficacy in RA patients.