Glomerular glucocorticoid receptor expression is reduced in late responders to steroids in adult-onset minimal change disease

Abstract

Background. Compared to children, adult patients with minimal change disease (MCD) tend to have a slower response to steroids, but little is known about the factors influencing the steroid responsiveness in these patients. In this study, we investigated the difference in the expression of the glomerular glucocorticoid receptor (GCR) according to steroid responsiveness in 28 adult-onset MCD patients. Methods. Based on the response to steroid treatment, the patients were divided into early responders (ER, n = 20) and late responders (LR, n = 8) according to the response to steroids on the basis of 4 weeks of treatment. The clinical and laboratory findings, and the glomerular mRNA and protein expression of GCR and nephrin, assessed by real-time polymerase chain reaction and immunohistochemistry, respectively, were compared between the ER and LR groups. Ten microscopic haematuric patients in whom renal biopsy was performed and revealed no histological abnormalities were included for control (C). Results. The mRNA expression of GCR was significantly lower in the LR than that in the ER group (P < 0.01), whereas it was comparable between the C and ER groups. GCR protein expression was also decreased in the LR compared with the C and ER groups. In contrast, there was no significant difference in nephrin mRNA expression among the three groups. On the other hand, the GCR mRNA expression correlated inversely with the time to complete remission (r = -0.49, P < 0.05), but not with the amount of proteinuria at presentation. Conclusion. In conclusion, the levels of glomerular GCR expression may be a useful predictor of steroid responsiveness in adult-onset MCD patients.