Clinical and biochemical impact of BCL1 polymorphic genotype of the glucocorticoid receptor gene in patients with adrenal incidentalomas

Pathophysiology of Mild Hypercortisolism: From the Bench to the Bedside

Mild hypercortisolism is defined as biochemical evidence of abnormal cortisol secretion without the classical detectable manifestations of overt Cushing’s syndrome and, above all, lacking catabolic characteristics such as central muscle weakness, adipose tissue redistribution, skin fragility and unusual infections. Mild hypercortisolism is frequently discovered in patients with adrenal incidentalomas, with a prevalence ranging between 5 and 50%. This high variability is mainly due to the different criteria used for defining this condition. This subtle cortisol excess has also been described in patients with incidentally discovered pituitary tumors with an estimated prevalence of 5%. To date, the mechanisms responsible for the pathogenesis of mild hypercortisolism of pituitary origin are still not well clarified. At variance, recent advances have been made in understanding the genetic background of bilateral and unilateral adrenal adenomas causing mild hypercortisolism. Some recent data suggest that the clinical effects of glucocorticoid (GC) exposure on peripheral tissues are determined not only by the amount of the adrenal GC production but also by the peripheral GC metabolism and by the GC sensitivity. Indeed, in subjects with normal cortisol secretion, the combined estimate of cortisol secretion, cortisone-to-cortisol peripheral activation by the 11 beta-hydroxysteroid dehydrogenase enzyme and GC receptor sensitizing variants have been suggested to be associated with the presence of hypertension, diabetes and bone fragility, which are three well-known consequences of hypercortisolism. This review focuses on the pathophysiologic mechanism underlying both the different sources of mild hypercortisolism and their clinical consequences (bone fragility, arterial hypertension, subclinical atherosclerosis, cardiovascular remodeling, dyslipidemia, glucose metabolism impairment, visceral adiposity, infections, muscle damage, mood disorders and coagulation).

Dexamethasone measurement during low-dose suppression test for suspected hypercortisolism: threshold development with and validation

BACKGROUND AND AIM

Dexamethasone Suppression Test (DST), recommended for Cushing's Syndrome (CS) diagnosis, explores the pituitary feedback to glucocorticoids. Its diagnostic accuracy could be affected by dexamethasone bioavailability, and therefore, we have developed and validated a dexamethasone threshold after 1-mg DST.

MATERIALS AND METHODS

We studied 200 subjects: 125 patients were considered retrospectively and 75 were enrolled prospectively as the validation cohort. Serum dexamethasone, Late Night Salivary Cortisol (LNSC), and Urinary Free Cortisol (UFC) were measured with LC-MS/MS. Normal LNSC and UFC levels were used to exclude CS. The lower 2.5th percentile of dexamethasone distribution in non-CS patients with cortisol ≤ 50 nmol/L after 1-mg DST was used as threshold.

RESULTS

16 patients were CS and 184 non-CS (108 adrenal incidentaloma and 76 excluded CS); 4.5 nmol/L resulted the calculated threshold. Cortisol after 1-mg DST confirmed high sensitivity (100% at 50 nmol/L cut-off) and moderate-low specificity (63%, increased to 91% at 138 nmol/L) to diagnose CS in the whole cohort of patients. We could reduce the number of false-positive results (from 10 to 6 and from 7 to 4 in AI and excluded CS) considering adequate dexamethasone levels. Dexamethasone levels were not affected by hypercortisolism, age, gender, smoke, weight, and creatinine. 6% of non-CS patients did not achieve adequate dexamethasone levels (40% of tests with serum cortisol > 138 nmol/L after 1-mg DST).

CONCLUSIONS

We developed and validated the routine dexamethasone measurement during 1-mg DST: it is independent from patient's clinical presentation, and it should be used to increase the specificity of serum cortisol levels.

Evaluation of body composition using dual-energy X-ray absorptiometry in patients with non-functioning adrenal incidentalomas and an intermediate phenotype: Is there an association with metabolic syndrome?

PURPOSE

Metabolic syndrome (MS) and sarcopenia are associated with increased cardiovascular risk. No studies using dual-energy x-ray absorptiometry (DXA) have evaluated association between body composition (BC) changes and MS in adrenal incidentaloma (AI). Our aim was to analyse BC in non-functioning AI (NFAI) and intermediate phenotype (IP) relative to controls and to correlate with cortisol levels.

METHODS

Cross-sectional study with 44 NFAI (serum cortisol ≤ 50 nmol/L after the overnight 1 mg dexamethasone suppression test), 27 IP (cortisol 51-138 nmol/L), and 41 controls (normal adrenal on imaging examination) using DXA. Autonomic cortisol secretion (cortisol > 138 nmol/L) was excluded from the study. BC data were compared using criteria for MS (World Health Organization, National Cholesterol Education Program-Adult Treatment Panel-III, American Association of Clinical Endocrinologists (AACE), and International Diabetes Federation).

RESULTS

There was no significant difference in clinical data and body mass index (BMI) among the three groups. Waist circumference (WC) was larger in AI vs. controls (p < 0.01). Waist-to-hip ratio was higher in NFAI vs. controls and waist-to-height ratio was higher in IP vs. controls (p = 0.03 and p = 0.02, respectively). The frequency of MS was higher in AI vs. controls. BC was not different among the groups. Patients with AI there was a significant association of MS with both an increase in total fat and body fat index (all criteria), and a significant difference between MS and smaller BMI-adjusted lean mass (AACE, p = 0.036). No correlation of cortisol after 1 mg dexamethasone test with BC or MS. AI and WC were independently associated with MS.

CONCLUSIONS

AI presented high frequency of MS and was independently associated with MS. Possible deleterious effects of cortisol secretion seem to initially affect the muscular system.

Analysis of BCLI, N363S and ER22/23EK Polymorphisms of the Glucocorticoid Receptor Gene in Adrenal Incidentalomas

CONTEXT

Patients with adrenal incidentalomas (AI) may experience detrimental consequences due to a minimal cortisol excess sustained by adrenal adenoma. SNPs of the glucocorticoid receptor gene (NR3C1) modulate individual sensitivity to glucocorticoids and may interfere with the clinical presentation.

OBJECTIVE

To compare the frequency of N363S, ER22/23EK and BclI SNPs in patients with AI with the general population and to evaluate whether these SNPs are linked to consequences of cortisol excess.

SETTING

Multicentric, retrospective analysis of patients referred from 2010 to 2014 to 4 centers (Orbassano, Milano, Messina [Italy] and Zagreb [Croatia]).

PATIENTS

411 patients with AI; 153 males and 258 females and 186 from blood donors.

MAIN OUTCOMES MEASURES

All patients and controls were genotyped for BclI, N363S and ER22/23EK and SNPs frequency was associated with clinical and hormonal features.

RESULTS

SNP frequency was: SNP frequency was: N363S 5.4% (MAF 0.027), BclI 54.7% (MAF 0.328), ER22/23EK 4.4% (MAF 0.022), without any significant difference between patients and controls. N363S was more frequent in hypertensive patients (p = 0.03) and was associated with hypertension (p = 0.015) in patients with suppressed cortisol after the 1-mg DST.

CONCLUSIONS

Our results demonstrate that SNPs of the glucocorticoid receptor gene do not play a pathogenetic role for AI. The impact of any single SNP on the phenotypic expression of minimal cortisol excess is limited and their analysis does not provide additional data that may be exploited for patient management.