Tissue mRNA expression of the glucocorticoid receptor and its splice variants in fatal critical illness.

BACKGROUND: Critical illness results in activation of the hypothalamic-pituitary-adrenal (HPA) axis, which might be accompanied by a peripheral adaptation in glucocorticoid sensitivity. Tissue sensitivity is determined by the active glucocorticoid receptor GRalpha, of which two splice variants involving the hormone-binding domain exist, GRbeta and GR-P. OBJECTIVE: To study tissue mRNA expression of the GR and its splice variants in fatal critical illness. DESIGN AND METHODS: We assessed mRNA expression of the GRalpha, GRbeta and GR-P variants in liver (n = 58) and muscle (n = 65) of patients who had died after intensive care, and had been randomized for insulin treatment. We analysed whether GR mRNA expression was associated with insulin treatment, cortisol levels and glucocorticoid treatment. RESULTS: GRalpha and GR-P mRNA constituted 87 +/- 8% and 13 +/- 2%, respectively, of total GR mRNA in liver. GRbeta mRNA could only be amplified in five liver samples. All variants were present in most muscle samples (alpha = 96 +/- 11%, P = 3.9 +/- 0.4%, beta = 0.010 +/- 0.002%). GR expression was not associated with insulin therapy. A strong positive relationship was observed between the different GR variants in both liver and muscle (P < 0.001 for all). Serum cortisol levels were negatively associated with liver GRalpha and muscle GR-P expression (P < 0.05). mRNA expression of both liver GRalpha and GR-P, but not muscle GR, was substantially lower in patients who had received exogenous glucocorticoids (P < 0.01). CONCLUSION: We demonstrate the presence of GRalpha and GR-P mRNA in liver and of GRalpha, GRbeta and GR-P mRNA in muscle, with no evidence for altered splicing in critical illness. In contrast to muscle GR, liver GR expression was substantially lower in patients receiving exogenous glucocorticoids.

A pilot study exploring the role of glucocorticoid receptor variants in primary biliary cirrhosis and primary sclerosing cholangitis.

BACKGROUND: In primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) significant therapeutic effects of glucocorticoids have not been documented. The most important clinical problem in patients with these diseases is fatigue, which is occasionally invalidating. Abnormalities in the hypothalamo-pituitary-adrenal axis have been suggested as a cause of fatigue. Most effects of glucocorticoids are mediated by the glucocorticoid receptor (hGR alpha). Recently a causative role for a splicing variant of the glucocorticoid receptor (hGR beta) has been proposed in glucocorticoid resistance in asthma and ulcerative colitis, whereas another splicing variant (hGR P) might be associated with glucocorticoid-resistant haematological malignancies. The aims of the present pilot study were to assess abnormalities in glucocorticoid receptor expression and to relate these abnormalities to the development of fatigue and to disease activity and severity in autoimmune cholestatic liver disease. METHODS: Five fatigued and five nonfatigued patients with PBC or PSC were included, and the results were compared with healthy controls. RESULTS: The expression of hGR P was not different from controls, but hGR beta mRNA was significantly increased (p=0.02) and hGR alpha mRNA decreased (p=0.015). There were no significant differences between fatigued and nonfatigued patients. A significant negative correlation between the serum activity of alkaline phosphatase and hGR alpha and hGR P mRNA was found. CONCLUSION: Although there was no relation with fatigue, abnormalities in hGR expression appear to occur in patients with these diseases, and may play a role in its pathophysiology and the poor response to glucocorticoid treatment.