Methylation of HPA axis related genes in men with hypersexual disorder

Hypersexual Disorder (HD) defined as non-paraphilic sexual desire disorder with components of compulsivity, impulsivity and behavioral addiction, and proposed as a diagnosis in the DSM 5, shares some overlapping features with substance use disorder including common neurotransmitter systems and dysregulated hypothalamic-pituitary-adrenal (HPA) axis function. In this study, comprising 67 HD male patients and 39 male healthy volunteers, we aimed to identify HPA-axis coupled CpG-sites, in which modifications of the epigenetic profile are associated with hypersexuality. The genome-wide methylation pattern was measured in whole blood using the Illumina Infinium Methylation EPIC BeadChip, measuring the methylation state of over 850K CpG sites. Prior to analysis, the global DNA methylation pattern was pre-processed according to standard protocols and adjusted for white blood cell type heterogeneity. We included CpG sites located within 2000bp of the transcriptional start site of the following HPA-axis coupled genes: Corticotropin releasing hormone (CRH), corticotropin releasing hormone binding protein (CRHBP), corticotropin releasing hormone receptor 1 (CRHR1), corticotropin releasing hormone receptor 2 (CRHR2), FKBP5 and the glucocorticoid receptor (NR3C1). We performed multiple linear regression models of methylation M-values to a categorical variable of hypersexuality, adjusting for depression, dexamethasone non-suppression status, Childhood Trauma Questionnaire total score and plasma levels of TNF-alpha and IL-6. Of 76 tested individual CpG sites, four were nominally significant (p<0.05), associated with the genes CRH, CRHR2 and NR3C1. Cg23409074-located 48bp upstream of the transcription start site of the CRH gene - was significantly hypomethylated in hypersexual patients after corrections for multiple testing using the FDR-method. Methylation levels of cg23409074 were positively correlated with gene expression of the CRH gene in an independent cohort of 11 healthy male subjects. The methylation levels at the identified CRH site, cg23409074, were significantly correlated between blood and four different brain regions. CRH is an important integrator of neuroendocrine stress responses in the brain, with a key role in the addiction processes. Our results show epigenetic changes in the CRH gene related to hypersexual disorder in men.

Second-line tests in the differential diagnosis of ACTH-dependent Cushing's syndrome

INTRODUCTION

Diagnosing Cushing's syndrome (CS) can be a challenge, especially in ACTH-dependent CS, when it comes to detecting the origin of ACTH secretion.

MATERIALS AND METHODS

Retrospective data were collected on 170 patients with ACTH-dependent CS (149 CD, 21 EAS) referring to two endocrinology units, focusing on three non-invasive tests: dexamethasone 8 mg overnight challenge (HDDST); corticotrophin-releasing hormone (CRH) assay and the desmopressin (DDAVP) test.

RESULTS

Patients with EAS were slightly older and had higher ACTH, serum and urinary cortisol levels than patients with CD (p < 0.01). CD patients had a stronger ACTH and cortisol response after CRH injection (p < 0.0001), and a more pronounced reduction in cortisol levels after HDDST (p < 0.0001). A threshold percentage ACTH increase after CRH stimulation of 72.4 % was able to identify CD with a sensitivity (SE) of 76 % (95 % CI 68-83) and a specificity (SP) of 100 % (95 % CI 83-100). As for HDDST, a cortisol suppression >52.7 % below the basal level suggested a pituitary origin with a SE of 88 % (95 % CI 81-93) and a SP of 90 % (95 % CI 68-99). There were no cases of EAS with positive responses to both these tests. Increases in ACTH and cortisol levels after the DDAVP test were also higher in CD than in EAS (p < 0.01), though the SE and SP were lower.

CONCLUSIONS

Patients with CD showed a stronger response to HDDST and CRH, and the adopted cut-offs showed a good SE and SP in discriminating them from patients with EAS. Concordant tests indicated CD when positive, whereas no response to either test was highly suggestive of EAS. The DDAVP test was of limited utility in the diagnostic phase. In conclusion, the choice of tests may play an important part in the differential diagnosis of ACTH-dependent CS.