OBJECTIVE: Cushing\'s syndrome is characterized by high morbidity and mortality with high interindividual variability. Easily measurable biomarkers, in addition to the hormone assays currently used for diagnosis, could reflect the individual biological impact of glucocorticoids. The aim of this study is to identify such biomarkers through the analysis of whole blood transcriptome.
METHODS: Whole blood transcriptome was evaluated in 57 samples from patients with overt Cushing\'s syndrome, mild Cushing\'s syndrome, eucortisolism, and adrenal insufficiency. Samples were randomly split into a training cohort to set up a Cushing\'s transcriptomic signature and a validation cohort to assess this signature.
METHODS: Total RNA was obtained from whole blood samples and sequenced on a NovaSeq 6000 System (Illumina). Both unsupervised (principal component analysis) and supervised (Limma) methods were used to explore the transcriptome profile. Ridge regression was used to build a Cushing\'s transcriptome predictor.
RESULTS: The transcriptomic profile discriminated samples with overt Cushing\'s syndrome. Genes mostly associated with overt Cushing\'s syndrome were enriched in pathways related to immunity, particularly neutrophil activation. A prediction model of 1500 genes built on the training cohort demonstrated its discriminating value in the validation cohort (accuracy .82) and remained significant in a multivariate model including the neutrophil proportion (P = .002). Expression of FKBP5, a single gene both overexpressed in Cushing\'s syndrome and implied in the glucocorticoid receptor signaling, could also predict Cushing\'s syndrome (accuracy .76).
CONCLUSIONS: Whole blood transcriptome reflects the circulating levels of glucocorticoids. FKBP5 expression could be a nonhormonal marker of Cushing\'s syndrome.

OBJECTIVE: To investigate the clinical, laboratory findings and signal intensity index (SII) on magnetic resonance imaging (MRI) of patients with bilateral and unilateral macronodular mild autonomous cortisol secretion (MACS).
METHODS: Clinical and laboratory findings of 81 patients with MACS were examined from retrospective records. SII of adenomas and internodular areas were evaluated by MRI. The unilateral group included patients with an adrenal macronodule (≥1 cm) in a single adrenal gland, while the bilateral group included patients with at least one macronodule in both adrenal glands.
RESULTS: In total, 46 patients were in the unilateral (57%), while 35 (43%) patients were in the bilateral groups. The dehydroepiandrosterone sulphate (DHEA-S) level was lower in the unilateral than in the bilateral group (p < .001). The presence of type 2 diabetes mellitus (T2DM), glycosylated haemoglobin (HbA1c) and low-density lipoprotein (LDL) concentrations were higher in the bilateral group (p < .05). However, no significant difference was detected in terms of adrenocorticotropic hormone (ACTH) and overnight 1 mg dexamethasone suppression test (DST) between the two groups (p > .05). There was no difference in SII between adenomas within the same patient, as well as between the unilateral and bilateral groups (p > .05). Logistic regression analysis based on the differentiation between unilateral and bilateral macronodular MACS demonstrated that DHEA-S, HbA1c and LDL concentrations were associated factors.
CONCLUSIONS: DHEA-S levels may not be as suppressed in patients with bilateral macronodular MACS as compared to those with unilateral adenoma. T2DM and hypercholesterolaemia have a higher frequency in bilateral patients. However, ACTH, overnight 1 mg DST and SII may not provide additional information for differentiation of bilaterality and unilaterality.

BACKGROUND: The impact of abnormal cortisol secretion on cognitive functions in patients with mild autonomous cortisol secretion (MACS) remains uncertain.
OBJECTIVE: To assess cognitive functions, determine serum brain-derived neurotrophic factor (BDNF) concentration in patients with MACS, and investigate the association between cognitive subdomains and BDNF.
METHODS: We prospectively recruited 84 participants-28 patients with MACS, 28 patients with nonfunctional adrenal adenoma (NFAA), and 28 control subjects matched for age, gender, body mass index (BMI), visceral adiposity, and educational level. The serum BDNF concentration of participants was measured. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition-focused interviews and Montreal Cognitive Assessments (MoCA) were carried out by an experienced psychiatrist.
RESULTS: Patients with MACS had a higher serum BDNF concentration than the NFAA (P = .001), while that of patients with NFAA was lower than the controls (P = .044). Linear regression analysis revealed BMI and morning cortisol after overnight 1 mg dexamethasone (DST) were mostly associated with BDNF (P < .05). No significant difference was found in MoCA scores between MACS and NFAA groups (P = .967), whereas those were lower than the control group (P = .004). When the cognitive subdomains were examined separately, MACS group performed higher memory score than NFAA (P = .045), but lower language scores than both the NFAA (P = .024) and control groups (P < .001). In the whole group, BDNF concentration was positively correlated with memory score (r = 0.337, P = .002), whereas DST was negatively correlated with language score (r = -0.355, P = .008).
CONCLUSIONS: Low-grade hypercortisolism is associated with elevated BDNF concentrations, which may be a protective factor for memory function in patients with MACS relative to those with NFAA.

Glucocorticoids (GCs) play an important role in metabolic adaptation, regulating carbohydrate-lipid homeostasis and the immune system. Because they also have anti-inflammatory and immunosuppressive properties, synthetic analogues of GCs have been developed and are widely used in the treatment of chronic inflammatory conditions and in organ transplantation. GCs are among the most commonly prescribed drugs in the world. However, long term and high GC doses can cause side effects such as GC-induced diabetes and lipodystrophy. In recent years, a large number of independent studies have reported the effects of constitutive and adipocyte-specific deletion of the GC receptor (GR) in mice under different diets and treatments, resulting in contrasting phenotypes. To avoid potential compensatory mechanisms associated with the constitutive adipocyte GR silencing during adipose tissue development, our team has generated an inducible mouse model of GR deletion specifically in the adipocyte (AdipoGR-KO). Using this mouse model, we were able to demonstrate the critical role of the adipocyte GR in GC-induced metabolic changes. Indeed, under conditions of hypercorticism, AdipoGR-KO mice showed an improvement in glucose tolerance and insulin sensitivity, as well as in lipid profile, despite a massive increase in adiposity. This result is explained by a densification of adipose tissue vascularization, highlighting the repressive role of adipocyte GR in the healthy expansion of this tissue. Our work has largely contributed to the demonstration of the important role of the adipocyte GR in the physiology and pathophysiology of the adipose tissue and its impact on energy homeostasis.

A retrospective cross-sectional study was conducted to assess the frequency of low-dose dexamethasone suppression test (LDDST) patterns in canine patients that had clinicopathologic signs consistent with Cushing\'s syndrome (CS). Medical records for patients of interest (N = 128) were reviewed between January 2014 and December 2020 to analyse and classify LDDST results based upon the following patterns: lack of suppression, partial suppression, complete suppression, escape, or inverse. Complete suppression, lack of suppression, partial suppression, escape, and inverse patterns were identified in 39.1%, 31.2%, 14.1%, 10.1% and 5.5% of cases respectively. LDDST results were also evaluated with respect to clinical signs, serum alkaline phosphatase (ALP) activity, urine specific gravity (USG) and adrenal ultrasonographic findings. There was no association between LDDST patterns and clinical signs (p = 0.11), increased ALP (p = 0.32), USG (p = 0.33) or adrenal ultrasonographic findings (p = 0.19). In all dogs that demonstrated complete suppression or an inverse pattern, CS was excluded by the attending clinician. The diagnosis of CS was also excluded without further exploration in 23.1%, 7.5% and 5.6% of dogs that demonstrated an escape pattern, lack of suppression and partial suppression pattern, respectively. These results suggest that the clinical significance of LDDST patterns, particularly escape and inverse patterns, are misunderstood by some clinicians, leading them to prematurely exclude the diagnosis of CS.

Osilodrostat is a novel potent oral steroidogenesis inhibitor with a non-steroidal chemical structure, recently approved for the treatment of adult patients with endogenous Cushing\'s syndrome, and Cushing\'s disease not cured bytab pituitary surgery or in whom pituitary surgery is not an option. Osilodrostat has been evaluated in different multicentre phase II and III clinical studies, and has shown to have notable effects, such as significant reductions in cortisol secretion, associated with significant improvement in body weight, blood pressure, glucose metabolism, lipid profile, psychological status and quality of life. The favourable safety profile, combined with the relevant efficacy, could make osilodrostat suitable as medical treatment in several phases of the Cushing\'s syndrome treatment journey: before surgery, as preoperative treatment, or instead of surgery, in cases where surgery is not an option or refused, as first-line treatment; after surgery, in cases of persistent or recurrent disease, as second-line treatment; after second surgery or radiotherapy following pituitary surgery as bridging treatment waiting for the definitive disease control, as third-line treatment. Further real-world clinical experience data are needed to confirm the current knowledge.

Cushing\'s syndrome (CS) arises from an excess of endogenous or exogenous cortisol, with Cushing\'s disease specifically implicating a pituitary adenoma and exaggerated adrenocorticotropic hormone (ACTH) production. Typically, Cushing\'s disease presents with characteristic symptoms such as weight gain, central obesity, moon face, and buffalo hump. This case report presents an unusual manifestation of CS in a 48-year-old male with a history of hypertension, where severe hypokalemia was the primary presentation. Initial complaints included bilateral leg swelling, muscle weakness, occasional shortness of breath, and a general feeling of not feeling well. Subsequent investigations revealed hypokalemia, metabolic alkalosis, and an abnormal response to dexamethasone suppression, raising concerns about hypercortisolism. Further tests, including 24-hour urinary free cortisol and ACTH testing, confirmed significant elevations. Brain magnetic resonance imaging (MRI) identified a pituitary macroadenoma, necessitating neurosurgical intervention. This case underscores the rarity of CS presenting with severe hypokalemia, highlighting the diagnostic challenges and the crucial role of a collaborative approach in managing such intricate cases.

The most common form of hypercortisolism is iatrogenic Cushing\'s syndrome. Lipodystrophy and metabolic disorders can result from the use of exogenous glucocorticoids (GC). Adipocytes play an important role in the production of circulating exosomal microRNAs, and knockdown of Dicer promotes lipodystrophy. The aim of this study is to investigate the effect of GCs on epididymal fat and to assess their influence on circulating microRNAs associated with fat turnover. The data indicate that despite the reduction in adipocyte volume due to increased lipolysis and apoptosis, there is no difference in tissue mass, suggesting that epididymal fat pad, related to animal size, is not affected by GC treatment. Although high concentrations of GC have no direct effect on epididymal microRNA-150-5p expression, GC can induce epididymal adipocyte uptake of microRNA-150-5p, which regulates transcription factor Ppar gamma during adipocyte maturation. In addition, GC treatment increased lipolysis and decreased glucose-derived lipid and glycerol incorporation. In conclusion, the similar control and GC epididymal fat mass results from increased dense fibrogenic tissue and decreased adipocyte volume induced by the lipolytic effect of GC. These findings demonstrate the complexity of epididymal fat. They also highlight how this disease alters fat distribution. This study is the first in a series published by our laboratory showing the detailed mechanism of adipocyte turnover in this disease.

BACKGROUND: The human adrenal cortex consists of three functionally and structurally distinct layers; zona glomerulosa, zona fasciculata (zF), and zona reticularis (zR), and produces adrenal steroid hormones in a layer-specific manner; aldosterone, cortisol, and adrenal androgens, respectively. Cortisol-producing adenomas (CPAs) occur mostly as a result of somatic mutations associated with the protein kinase A pathway. However, how CPAs develop after adrenocortical cells acquire genetic mutations, remains poorly understood.
METHODS: We conducted integrated approaches combining the detailed histopathologic studies with genetic, RNA-sequencing, and spatially resolved transcriptome (SRT) analyses for the adrenal cortices adjacent to human adrenocortical tumours.
RESULTS: Histopathological analysis revealed an adrenocortical nodular structure that exhibits the two-layered zF- and zR-like structure. The nodular structures harbour GNAS somatic mutations, known as a driver mutation of CPAs, and confer cell proliferative and autonomous steroidogenic capacities, which we termed steroids-producing nodules (SPNs). RNA-sequencing coupled with SRT analysis suggests that the expansion of the zF-like structure contributes to the formation of CPAs, whereas the zR-like structure is characterised by a macrophage-mediated immune response.
CONCLUSIONS: We postulate that CPAs arise from a precursor lesion, SPNs, where two distinct cell populations might contribute differently to adrenocortical tumorigenesis. Our data also provide clues to the molecular mechanisms underlying the layered structures of human adrenocortical tissues.
BACKGROUND: KAKENHI, The Uehara Memorial Foundation, Daiwa Securities Health Foundation, Kaibara Morikazu Medical Science Promotion Foundation, Secom Science and Technology Foundation, ONO Medical Research Foundation, and Japan Foundation for Applied Enzymology.

Cushing\'s syndrome (CS) is a complex disorder characterized by the excessive secretion of cortisol, with Cushing\'s disease (CD), particularly associated with pituitary tumors, exhibiting heightened morbidity and mortality. Although transsphenoidal pituitary surgery (TSS) stands as the primary treatment for CD, there is a crucial need to optimize patient prognosis. Current medical therapy serves as an adjunctive measure due to its unsatisfactory efficacy and unpredictable side effects. In this comprehensive review, we delve into recent advances in understanding the pathogenesis of CS and explore therapeutic options by conducting a critical analysis of potential drug targets and candidates. Additionally, we provide an overview of the design strategy employed in previously reported candidates, along with a summary of structure-activity relationship (SAR) analyses and their biological efficacy. This review aims to contribute valuable insights to the evolving landscape of CS research, shedding light on potential avenues for therapeutic development.