Untargeted Plasma Metabolomics Unravels a Metabolic Signature for Tissue Sensitivity to Glucocorticoids in Healthy Subjects: Its Implications in Dietary Planning for a Healthy Lifestyle

In clinical practice, differences in glucocorticoid sensitivity among healthy subjects may influence the outcome and any adverse effects of glucocorticoid therapy. Thus, a fast and accurate methodology that could enable the classification of individuals based on their tissue glucocorticoid sensitivity would be of value. We investigated the usefulness of untargeted plasma metabolomics in identifying a panel of metabolites to distinguish glucocorticoid-resistant from glucocorticoid-sensitive healthy subjects who do not carry mutations in the human glucocorticoid receptor (NR3C1) gene. Applying a published methodology designed for the study of glucocorticoid sensitivity in healthy adults, 101 healthy subjects were ranked according to their tissue glucocorticoid sensitivity based on 8:00 a.m. serum cortisol concentrations following a very low-dose dexamethasone suppression test. Ten percent of the cohort, i.e., 11 participants, on each side of the ranking, with no NR3C1 mutations or polymorphisms, were selected, respectively, as the most glucocorticoid-sensitive and most glucocorticoid-resistant of the cohort to be analyzed and compared with untargeted blood plasma metabolomics using gas chromatography–mass spectrometry (GC–MS). The acquired metabolic profiles were evaluated using multivariate statistical analysis methods. Nineteen metabolites were identified with significantly lower abundance in the most sensitive compared to the most resistant group of the cohort, including fatty acids, sugar alcohols, and serine/threonine metabolism intermediates. These results, combined with a higher glucose, sorbitol, and lactate abundance, suggest a higher Cori cycle, polyol pathway, and inter-tissue one-carbon metabolism rate and a lower fat mobilization rate at the fasting state in the most sensitive compared to the most resistant group. In fact, this was the first study correlating tissue glucocorticoid sensitivity with serine/threonine metabolism. Overall, the observed metabolic signature in this cohort implies a worse cardiometabolic profile in the most glucocorticoid-sensitive compared to the most glucocorticoid-resistant healthy subjects. These findings offer a metabolic signature that distinguishes most glucocorticoid-sensitive from most glucocorticoid-resistant healthy subjects to be further validated in larger cohorts. Moreover, they support the correlation of tissue glucocorticoid sensitivity with insulin resistance and metabolic syndrome-associated pathways, further emphasizing the need for nutritionists and doctors to consider the tissue glucocorticoid sensitivity in dietary and exercise planning, particularly when these subjects are to be treated with glucocorticoids.

Letter to the Editor: “Glucocorticoid Resistance in Premature Adrenarche and PCOS: From Childhood to Adulthood”

The conclusion of Panayiotopoulos et al. that glucocorticoid resistance accounted for 57% to 67% of their premature adrenarche and polycystic ovary syndrome cases cannot be accepted from the data presented. This is because proper validation of their method for determining glucocorticoid sensitivity is not presented. Furthermore, the method seems insensitive to physiologic glucocorticoid concentrations.

Glucocorticoid Resistance in Premature Adrenarche and PCOS: From Childhood to Adulthood

Context We hypothesize that impaired glucocorticoid sensitivity (GC sensitivity) plays a role in the development of premature adrenarche (PA) and polycystic ovarian syndrome (PCOS) by increasing androgen synthesis. Objective To study glucocorticoid sensitivity in vitro in subjects with PA and PCOS. Patients and Methods Fourteen subjects (10 girls, 4 boys, 6.9 ± 0.6 years) with PA; 27 subjects with PCOS (17 ± 2.5 years) and 31 healthy controls were enrolled in the study. All subjects and controls underwent GC sensitivity analysis in vitro using a fluorescein labeled-dexamethasone (F-DEX) assay. A GC sensitivity index (GCSI) was calculated as area under the curve of the F-DEX assay results. Subjects were classified as GC resistant if the GCSI ≤ 264 and GC sensitive if the GCSI ≥ 386. Results In the PA group, 8 of 14 subjects were resistant with GCSI of 179.7 ± 39.9, 4 were within the normal range with GCSI of 299.6 ± 27.9, and 2 had increased GC sensitivity with GCSI of 423.5 ± 47.9. In the PCOS group, 18 of 27 subjects were GC-resistant with GCSI of 180.9 ± 58.2, 8 were within the normal range with GCSI of 310.7 ± 26.4, and 1 had increased GCSI of 395.4. In the PCOS GC-resistant subgroup, cortisol was higher compared with PCOS with normal GCSI (P < 0.05). In the combined PCOS plus female control group, GCSI correlated negatively with cortisol and testosterone (P < 0.05). Conclusion GC resistance was found in more than 50% of patients with PCOS and PA. The findings strongly suggest that GC resistance is associated with states of PA and PCOS.