The corticotrophin-releasing factor/urocortin system regulates white fat browning in mice through paracrine mechanisms

Objectives: The corticotrophin-releasing factor (CRF)/urocortin system is expressed in the adipose tissue of mammals, but its functional role in this tissue remains unknown. Methods: Pharmacological manipulation of the activity of CRF receptors, CRF1 and CRF2, was performed in 3T3L1 white pre-adipocytes and T37i brown pre-adipocytes during in vitro differentiation. The expression of genes of the CRF/urocortin system and of markers of white and brown adipocytes was evaluated along with mitochondrial biogenesis and cellular oxygen consumption. Metabolic evaluation of corticosterone-deficient or supplemented Crhr1-null (Crhr1−/−) mice and their wild-type controls was performed along with gene expression analysis carried out in white (WAT) and brown (BAT) adipose tissues. Results: Peptides of the CRF/urocortin system and their cognate receptors were expressed in both pre-adipocyte cell lines. In vitro pharmacological studies showed an inhibition of the expression of the CRF2 pathway by the constitutive activity of the CRF1 pathway. Pharmacological activation of CRF2 and, to a lesser extent, inhibition of CRF1 signaling induced molecular and functional changes indicating transdifferentiation of white pre-adipocytes and differentiation of brown pre-adipocytes. Crhr1−/− mice showed increased expression of CRF2 and its agonist Urocortin 2 in adipocytes that was associated to brown conversion of WAT and activation of BAT. Crhr1−/− mice were resistant to diet-induced obesity and glucose intolerance. Restoring physiological circulating corticosterone levels abrogated molecular changes in adipocytes and the favorable phenotype of Crhr1−/− mice. Conclusions: Our findings suggest the importance of the CRF2 pathway in the control of adipocyte plasticity. Increased CRF2 activity in adipocytes induces browning of WAT, differentiation of BAT and is associated with a favorable metabolic phenotype in mice lacking CRF1. Circulating corticosterone represses CRF2 activity in adipocytes and may thus regulate adipocyte physiology through the modulation of the local CRF/urocortin system. Targeting CRF receptor signaling specifically in the adipose tissue may represent a novel approach to tackle obesity

Functional role of T-cell receptor nanoclusters in signal initiation and antigen discrimination

Antigen recognition by the T-cell receptor (TCR) is a hallmark of the adaptive immune system. When the TCR engages a peptide bound to the restricting major histocompatibility complex molecule (pMHC), it transmits a signal via the associated CD3 complex. How the extracellular antigen recognition event leads to intracellular phosphorylation remains unclear. Here, we used single-molecule localization microscopy to quantify the organization of TCR–CD3 complexes into nanoscale clusters and to distinguish between triggered and nontriggered TCR–CD3 complexes. We found that only TCR–CD3 complexes in dense clusters were phosphorylated and associated with downstream signaling proteins, demonstrating that the molecular density within clusters dictates signal initiation. Moreover, both pMHC dose and TCR–pMHC affinity determined the density of TCR–CD3 clusters, which scaled with overall phosphorylation levels. Thus, TCR–CD3 clustering translates antigen recognition by the TCR into signal initiation by the CD3 complex, and the formation of dense signaling-competent clusters is a process of antigen discrimination

Endocrinology in the time of COVID-19: Management of Cushing’s syndrome

Clinical evaluation should guide those needing immediate investigation. Strict adherence to COVID-19 protection measures is necessary. Alternative ways of consultations (telephone, video) should be used. Early discussion with regional/national experts about investigation and management of potential and existing patients is strongly encouraged. Patients with moderate or severe clinical features need urgent investigation and management. Patients with active Cushing’s syndrome, especially when severe, are immunocompromised and vigorous adherence to the principles of social isolation is recommended. In patients with mild features or in whom a diagnosis is less likely, clinical re-evaluation should be repeated at 3 and 6 months or deferred until the prevalence of SARS-CoV-2 has significantly decreased; however, those individuals should be encouraged to maintain social distancing. Diagnostic pathways may need to be very different from usual recommendations in order to reduce possible exposure to SARS-CoV-2. When extensive differential diagnostic testing and/or surgery is not feasible, it should be deferred and medical treatment should be initiated. Transsphenoidal pituitary surgery should be delayed during high SARS-CoV-2 viral prevalence. Medical management rather than surgery will be the used for most patients, since the short- to mid-term prognosis depends in most cases on hypercortisolism rather than its cause; it should be initiated promptly to minimize the risk of infection in these immunosuppressed patients. The risk/benefit ratio of these recommendations will need re-evaluation every 2–3 months from April 2020 in each country (and possibly local areas) and will depend on the local health care structure and phase of pandemic

Can single molecule localization microscopy be used to map closely spaced RGD nanodomains?

Cells sense and respond to nanoscale variations in the distribution of ligands to adhesion receptors. This makes single molecule localization microscopy (SMLM) an attractive tool to map the distribution of ligands on nanopatterned surfaces. We explore the use of SMLM spatial cluster analysis to detect nanodomains of the cell adhesion-stimulating tripeptide arginine-glycine-aspartic acid (RGD). These domains were formed by the phase separation of block copolymers with controllable spacing on the scale of tens of nanometers. We first determined the topology of the block copolymer with atomic force microscopy (AFM) and then imaged the localization of individual RGD peptides with direct stochastic optical reconstruction microscopy (dSTORM). To compare the data, we analyzed the dSTORM data with DBSCAN (density-based spatial clustering application with noise). The ligand distribution and polymer topology are not necessary identical since peptides may attach to the polymer outside the nanodomains and/or coupling and detection of peptides within the nanodomains is incomplete. We therefore performed simulations to explore the extent to which nanodomains could be mapped with dSTORM. We found that successful detection of nanodomains by dSTORM was influenced by the inter-domain spacing and the localization precision of individual fluorophores, and less by non-specific absorption of ligands to the substratum. For example, under our imaging conditions, DBSCAN identification of nanodomains spaced further than 50 nm apart was largely independent of background localisations, while nanodomains spaced closer than 50 nm required a localization precision of ~11 nm to correctly estimate the modal nearest neighbor distance (NDD) between nanodomains. We therefore conclude that SMLM is a promising technique to directly map the distribution and nanoscale organization of ligands and would benefit from an improved localization precision

Update on Medical Treatment of Cushing’s Syndrome

First-line treatment of endogenous Cushing’s syndrome (CS) is surgical removal of the tumor responsible for cortisol excess. However, medical therapy has an established role in treatment when patients are not surgical candidates or decline surgery, residual or recurrent disease is present and not amenable to repeat resection, and control of hypercortisolism is needed either preoperatively or while awaiting the effects of radiotherapy. The approach to medical therapy should be tailored based on the etiology, degree of hypercortisolism, and patient characteristics. Currently available medical therapy for all etiologies of CS either blocks adrenal production of cortisol or blocks its action at the level of the glucocorticoid receptor. Currently available medical therapy for Cushing’s disease (CD) targets the adrenocorticotropic hormone-secreting pituitary tumor through activation of somatostatin and dopamine receptors, alkylating DNA damage, or immune system activation. More focused therapy with greater efficacy and fewer adverse effects is needed, particularly in the case of CD, with potential targets and drugs identified and in development.</p

Use of late-night salivary cortisol to monitor response to medical treatment in Cushing’s disease

Objective Monitoring of patients with Cushing’s disease on cortisol-lowering drugs is usually performed with urinary free cortisol (UFC). Late-night salivary cortisol (LNSC) has an established role in screening for hypercortisolism and can help to detect the loss of cortisol circadian rhythm. Less evidence exists regarding the usefulness of LNSC in monitoring pharmacological response in Cushing’s disease. Design Exploratory analysis evaluating LNSC during a Phase III study of long-acting pasireotide in Cushing’s disease (clinicaltrials.gov: NCT01374906). Methods Mean LNSC (mLNSC) was calculated from two samples, collected on the same days as the first two of three 24-h urine samples (used to calculate mean UFC [mUFC]). Clinical signs of hypercortisolism were evaluated over time. Results At baseline, 137 patients had evaluable mLNSC measurements; 91.2% had mLNSC exceeding the upper limit of normal (ULN; 3.2 nmol/L). Of patients with evaluable assessments at month 12 (n = 92), 17.4% had both mLNSC ≤ULN and mUFC ≤ULN; 22.8% had mLNSC ≤ULN, and 45.7% had mUFC ≤ULN. There was high variability in LNSC (intra-patient coefficient of variation (CV): 49.4%) and UFC (intra-patient CV: 39.2%). mLNSC levels decreased over 12 months of treatment and paralleled changes in mUFC. Moderate correlation was seen between mLNSC and mUFC (Spearman’s correlation: ρ = 0.50 [all time points pooled]). Greater improvements in systolic/diastolic blood pressure and weight were seen in patients with both mLNSC ≤ULN and mUFC ≤ULN. Conclusion mUFC and mLNSC are complementary measurements for monitoring treatment response in Cushing’s disease, with better clinical outcomes seen for patients in whom both mUFC and mLNSC are controlled

AME position statement on adrenal incidentaloma.

Objective: To assess currently available evidence on adrenal incidentaloma and provide recommendations for clinical practice. Design: A panel of experts (appointed by the Italian Association of Clinical Endocrinologists (AME)) appraised the methodological quality of the relevant studies, summarized their results, and discussed the evidence reports to find consensus. Radiological assessment: Unenhanced computed tomography (CT) is recommended as the initial test with the use of an attenuation value of <= 10 Hounsfield units (HU) to differentiate between adenomas and non-adenomas. For tumors with a higher baseline attenuation value, we suggest considering delayed contrast-enhanced CT studies. Positron emission tomography (PET) or PET/CT should be considered when CT is inconclusive, whereas fine needle aspiration biopsy may be used only in selected cases suspicious of metastases (after biochemical exclusion of pheochromocytoma). Hormonal assessment: Pheochromocytoma and excessive overt cortisol should be ruled out in all patients, whereas primary aldosteronism has to be considered in hypertensive and/or hypokalemic patients. The 1 mg overnight dexamethasone suppression test is the test recommended for screening of subclinical Cushing's syndrome (SCS) with a threshold at 138 nmol/l for considering this condition. A value of 50 nmol/l virtually excludes SCS with an area of uncertainty between 50 and 138 nmol/l. Management: Surgery is recommended for masses with suspicious radiological aspects and masses causing overt catecholamine or steroid excess. Data are insufficient to make firm recommendations for or against surgery in patients with SCS. However, adrenalectomy may be considered when an adequate medical therapy does not reach the treatment goals of associated diseases potentially linked to hypercortisolism

Time Until Partial Response in Metastatic Adrenocortical Carcinoma Long-Term Survivors

A partial response (PR) has been proposed as a surrogate for overall survival in advanced adrenocortical carcinoma (ACC). The primary endpoint of the study was to characterize the time until a PR in patients with metastatic ACC treated with a standard therapy is achieved. Long-term survivors were selected to allow evaluation of delayed tumor response to mitotane. Records from patients with metastatic ACC that survived for &gt; 24 months were retrieved. Tumor response was analyzed according to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Time until a tumor response, after treatment initiation or therapeutic plasma mitotane level, was analyzed. Sixty-eight patients were analyzed. The first-line systemic therapy was mitotane as a monotherapy (M) (n = 57) or cytotoxic polychemotherapy plus/minus mitotane (PC ± M) (n = 11). The second-line therapy was M (n = 2) or PC ± M (n = 41). Thirty-two PRs occurred in 30/68 patients (44.1%): this was obtained for 13 (40.6%) during M and during PC ± M for 19/32 responders (59.4%). PRs were observed within 6 months of starting M or PC ± M in 76.9 and 94.7% of responses, respectively, within 6 months of therapeutic plasma mitotane being first observed in 88.9% of responses with M and in 53.3% of responses with PC ± M. All PRs (but one) occurred within 1 year after initiating treatment. To conclude, Most patients with metastatic ACC and long survival times had PRs within the first 6 months of standard systemic therapy, and almost all within the first year. The absence of response after that period could be considered as a treatment failure. Maintenance of mitotane therapy in non-responders after 1 year should be questioned in future randomized trials

Prognostic factors in stage III-IV adrenocortical carcinomas (ACC): an European Network for the Study of Adrenal Tumor (ENSAT) study.

BACKGROUND: The clinical course of advanced adrenocortical carcinoma (ACC) is heterogeneous. Our study aimed primarily to refine and make headway in the prognostic stratification of advanced ACC. PATIENTS AND METHODS: Patients with advanced ENSAT ACC (stage III or stage IV) at diagnosis registered between 2000 and 2009 in the ENSAT database were enrolled. The primary end point was overall survival (OS). Parameters of potential prognostic relevance were selected. Univariate and multivariate analyses were carried out: model 1 'before surgery'; model 2 'post-surgery'. RESULTS: Four hundred and forty-four patients with advanced ENSAT ACC (stage III: 210; stage IV: 234) were analyzed. After a median follow-up of 55.2 months, the median OS was 24 months. A modified ENSAT (mENSAT) classification was validated: stage III (invasion of surrounding tissues/organs or the vena renalis/cava) and stage IVa, IVb, IVc (2, 3 or >3 metastatic organs, including N, respectively). Two- or 5-year OS was 73%, 46%, 26% and 15% or 50%, 15%, 14% and 2% for stages III, IVa, IVb and IVc, respectively. In the multivariate analysis, mENSAT stages (stages IVa, IVb, or IVc, respectively) were significantly correlated with OS (P 6 and/or Ki67 ≥20%, P = 0.06) in model 2. CONCLUSION: The mENSAT classification and GRAS parameters (Grade, R status, Age and Symptoms) were found to best stratify the prognosis of patients with advanced ACC

Improvement in clinical features of hypercortisolism during osilodrostat treatment: findings from the phase III LINC 3 trial in Cushing's disease

Purpose Cushing’s disease is associated with substantial morbidity and impaired quality of life (QoL) resulting from excess cortisol exposure. The current study explored improvements in clinical signs and additional specific manifestations of hypercortisolism during osilodrostat (potent oral 11β-hydroxylase inhibitor) therapy by degree of control of mean urinary free cortisol (mUFC). Methods LINC 3 (NCT02180217) was a prospective, open-label, 48-week study of osilodrostat (starting dose: 2 mg bid; maximum: 30 mg bid) that enrolled 137 adults with Cushing’s disease and mUFC > 1.5 times the upper limit of normal (ULN). mUFC (normal range 11‒138 nmol/24 h), cardiometabolic parameters (blood pressure, weight, waist circumference, body mass index, total cholesterol, fasting plasma glucose, glycated haemoglobin), physical manifestations of hypercortisolism (facial rubor, striae, fat distribution, bruising, hirsutism [females], muscle atrophy) and QoL were evaluated. mUFC was defined as controlled if ≤ ULN, partially controlled if > ULN but ≥ 50% reduction from baseline, and uncontrolled if > ULN and < 50% reduction from baseline. Concomitant medications were permitted throughout the study. Results At weeks 24 and 48, respectively, mUFC was controlled in 93 (67.9%) and 91 (66.4%) patients, partially controlled in 20 (14.6%) and 13 (9.5%), and uncontrolled in 24 (17.5%) and 33 (24.1%). Overall, mean improvements from baseline in cardiometabolic at week 24 were greater in patients with controlled or partially controlled versus uncontrolled mUFC; at week 48, improvements occurred irrespective of mUFC control. Generally, physical manifestations and QoL progressively improved from baseline irrespective of mUFC control. Conclusions Improvements in clinical signs and additional specific manifestations of hypercortisolism associated with Cushing’s disease occurred alongside decreases in mUFC