Epigenetic modulation of DNA Is associated with fatigue, depression and anxiety in patients with Cushing's syndrome in remission: A genome-wide methylation study
The Endocrine Society's 97th Annual Meeting & Expo (ENDO 2015) — CAM Glad, JC Andersson-Assarsson, P Berglund, R Bergthorsdottir, O Ragnarsson, G Johannsson | March 06, 2015
Summary: Researchers conducted this study to determine whether patients with Cushing's syndrome (CS) that is in remission have specific epigenetic alterations that are associated with persistent cognitive impairments, anxiety, fatigue, and depression. Patients with CS in remission were shows to have specific DNA methylation that differed from that of healthy controls and was strongly correlated with clinical traits of anxiety, depression and fatigue, they concluded, adding that their results may suggest that an interaction between the glucocorticoid and the retinoic acid receptor is implicated in the long-term outcome of patients with CS in remission. The persistent cognitive impairment observed in patients with CS in remission, therefore, may be due to epigenetic modulation of DNA, they concluded.
- For this cross-sectional, case-controlled, single center study, researchers included 48 women with CS in remission (mean age±SD: 52.9±14 years) and 16 controls (mean age±SD: 53.6±16 years) matched for age, gender and educational level.
- The mean age at diagnosis of CS was 37±14 years and the median (interquartile range) duration of remission was 13 (5-19) years.
- In all, 37 patients had Cushing’s disease (CD) and 11 had a cortisol producing adrenal adenoma.
- Researchers used the fatigue impact scale (FIS) to evaluate fatigue, and the comprehensive psychopathological rating scale to evaluate depression and anxiety; they assessed cognitive function by standardized neuropsychological tests.
- DNA was isolated from whole blood, and DNA methylation was analyzed on the Illumina Infinium HumanMethylation450K BeadChip, which simultaneously interrogates >465,000 methylation sites per sample.
- Researchers performed data quality control and analysis using the ChAMP methylation analysis package in R, and used Spearmen's rho to perform correlation analyses.
- Researchers found that patients had higher median score for FIS, depression and anxiety.
- Methylation analysis identified 3,903 probes (in 340 genes) in regions that were differently methylated between CS patients and controls, and they found that 28% of these were significantly correlated to at least one of the clinical traits.
- Fatigue, depression and anxiety were the most commonly correlated traits, and two of the most highly correlated genes were RXRB and COL11A2.
- Gene ontology analysis revealed that these belong to the same GO-terms and are involved in retinoic acid receptor activity.
- Finally, researchers found that both genes were specifically hypomethylated in cases as compared to controls.
This project has received financial support from the Swedish federal government under the LUA/ALF agreement, The Health & Medical Care Committee of the Regional Executive Board, Region Västra Götaland, The Swedish Society of Medicine and The Swedish Society of Endocrinology.