Purpose Cushing’s disease (CD), also known as pituitary-dependent hyperadrenocorticism, is caused by adrenocorticotropic hormone (ACTH)-secreting pituitary tumours. Affected humans and dogs have similar clinical manifestations, however, the incidence of the canine disease is thousand-fold higher. This makes the dog an obvious model for studying the pathogenesis of pituitary-dependent hyperadrenocorticism. Despite certain similarities identified at the molecular level, the question still remains whether the two species have a shared oncogenetic background. Recently, hotspot recurrent mutations in the gene encoding for ubiquitin specific protease 8 (USP8) have been identified as the main driver behind the formation of ACTH-secreting pituitary adenomas in humans. In this study, we aimed to verify whether USP8 mutations also play a role in the development of such tumours in dogs. Methods Presence of USP8 mutations was analysed by Sanger and PCR-cloning sequencing in 38 canine ACTH-secreting adenomas. Furthermore, the role of USP8 and EGFR protein expression was assessed by immunohistochemistry in a subset of 25 adenomas. Results None of the analysed canine ACTH-secreting adenomas presented mutations in the USP8 gene. In a subset of these adenomas, however, we observed an increased nuclear expression of USP8, a phenotype characteristic for the USP8 mutated human tumours, that correlated with smaller tumour size but elevated ACTH production in those tumours. Conclusions Canine ACTH-secreting pituitary adenomas lack mutations in the USP8 gene suggesting a different genetic background of pituitary tumourigenesis in dogs. However, elevated nuclear USP8 protein expression in a subset of tumours was associated with a similar phenotype as in their human counterparts, indicating a possible end-point convergence of the different genetic backgrounds in the two species. In order to establish the dog as a useful animal model for the study of CD, further comprehensive studies are needed.

We assume that a specific health constraint, e.g., a certain aspect of bodily function or quality of life that is measured by a variable X, is absent (or irrelevant) in a healthy reference population (Ref0), and it is materially present and precisely measured in a diseased reference population (Ref1). We further assume that some amount of this constraint of interest is suspected to be present in a population under study (SP). In order to quantify this issue, we propose the introduction of an intuitive measure, the population comparison index (PCI), that relates the mean value of X in population SP to the mean values of X in populations Ref0 and Ref1. This measure is defined as PCI[X] = (mean[X|SP] − mean[X|Ref0])/(mean[X|Ref1] − mean[X|Ref0]) × 100[%], where mean[X|.] is the average value of X in the respective group of individuals. For interpretation, PCI[X] ≈ 0 indicates that the values of X in the population SP are similar to those in population Ref0, and hence, the impairment measured by X is not materially present in the individuals in population SP. On the other hand, PCI[X] ≈ 100 means that the individuals in SP exhibit values of X comparable to those occurring in Ref1, i.e., the constraint of interest is equally present in populations SP and Ref1. A value of 0 < PCI[X] < 100 indicates that a certain percentage of the constraint is present in SP, and it is more than in Ref0 but less than in Ref1. A value of PCI[X] > 100 means that population SP is even more affected by the constraint than population Ref1.

Background Although surgery is considered the first-line treatment for patients with endogenous Cushing’s syndrome (CS), medical therapy is often required to control severe hypercortisolism. Metyrapone and osilodrostat are both steroidogenic inhibitors targeting the 11β-hydroxylase, however, their therapeutic effectiveness has not yet been directly compared. This study aimed to evaluate metyrapone and osilodrostat in the short-term therapy of CS. Methods Retrospective analysis of patients with endogenous CS treated with metyrapone or osilodrostat as monotherapy for at least 4 weeks. Main outcome measures were serum cortisol and 24h urinary free cortisol (UFC) at baseline (T0) and after 2 (T1), 4 (T2), and 12 weeks (T3) of therapy. Results 16 patients with endogenous CS were identified (pituitary n=7, adrenal n=4, ectopic CS n=5). Each 8 patients were treated with metyrapone and osilodrostat. Despite heterogeneity, both groups showed comparable mean UFC levels at T0 (metyrapone: 758 µg/24h vs osilodrostat: 817 µg/24h; p=0.93). From T0 to T1, the decrease of UFC was less pronounced under metyrapone than osilodrostat (-21.3% vs -68.4%; median daily drug dose: 1000 mg vs 4 mg). This tendency persisted at T2 (-37.3% vs -50.1%; median drug dose: 1250 mg vs 6 mg) while at T3 a decrease in UFC from T0 was more pronounced in the metyrapone group (-71.5% vs -51.5%; median dose 1250 mg vs 7 mg). Under osilodrostat, a QTc-interval prolongation was identified at T3 (mean 432 ms vs 455 ms). From T0 to T2, the number of antihypertensive drugs remained comparable under metyrapone and decreased under osilodrostat (n= -0.3 vs n= -1.0). Conclusion Although both drugs show comparable therapeutic efficacy, osilodrostat seems to reduce cortisol levels and to control blood pressure faster.

Background Adrenal incidentalomas with cortisol autonomy are associated with increased cardiovascular morbidity and mortality. Specific data on the clinical and biochemical course of affected patients are lacking. Methods Retrospective study from a tertiary referral centre in Germany. After exclusion of overt hormone excess, malignancy and glucocorticoid medication, patients with adrenal incidentalomas were stratified according to serum cortisol after 1 mg dexamethasone: autonomous cortisol secretion (ACS), >5.0; possible ACS (PACS), 1.9-5.0; non-functioning adenomas (NFA), ≤1.8 µg/dl. Results A total of 260 patients were enrolled (147 women (56.5%), median follow-up 8.8 (2.0-20.8) years). At initial diagnosis, median age was 59.5 (20-82) years, and median tumour size was 27 (10-116) mm. Bilateral tumours were more prevalent in ACS (30.0%) and PACS (21.9%) than in NFA (8.1%). Over time, 40/124 (32.3%) patients had a shift of their hormonal secretion pattern (NFA to PACS/ACS, n=15/53; PACS to ACS, n=6/47; ACS to PACS, n=11/24; PACS to NFA, n=8/47). However, none of the patients developed overt Cushing’s syndrome. Sixty-one patients underwent adrenalectomy (NFA, 17.9%; PACS, 24.0%; ACS, 39.0%). When non-operated patients with NFA were compared to PACS and ACS at last follow-up, arterial hypertension (65.3% vs. 81.9% and 92.0%; p<0.05), diabetes (23.8% vs. 35.6% and 40.0%; p<0.01), and thromboembolic events (PACS: HR 3.43, 95%-CI 0.89-13.29; ACS: HR 5.96, 95%-CI 1.33-26.63; p<0.05) were significantly less frequent, along with a trend towards a higher rate of cardiovascular events in case of cortisol autonomy (PACS: HR 2.23, 95%-CI 0.94-5.32; ACS: HR 2.60, 95%-CI 0.87-7.79; p=0.1). Twenty-five (12.6%) of the non-operated patients died, with higher overall mortality in PACS (HR 2.6, 95%-CI 1.0-4.7; p=0.083) and ACS (HR 4.7, 95%-CI 1.6-13.3; p<0.005) compared to NFA. In operated patients, prevalence of arterial hypertension decreased significantly (77.0% at diagnosis to 61.7% at last follow-up; p<0.05). The prevalence of cardiovascular events and mortality did not differ significantly between operated and non-operated patients, whereas thromboembolic events were significantly less frequent in the surgical treatment group. Conclusion Our study confirms relevant cardiovascular morbidity in patients with adrenal incidentalomas (especially those with cortisol autonomy). These patients should therefore be monitored carefully, including adequate treatment of typical cardiovascular risk factors. Adrenalectomy was associated with a significantly decreased prevalence of hypertension. However, more than 30% of patients required reclassification according to repeated dexamethasone suppression tests. Thus, cortisol autonomy should ideally be confirmed before making any relevant treatment decision (e.g. adrenalectomy).

Purpose Pheochromocytomas and Paragangliomas (PPGL) result in chronic catecholamine excess and serious health complications. A recent study obtained a metabolic signature in plasma from PPGL patients; however, its targeted nature may have generated an incomplete picture and a broader approach could provide additional insights. We aimed to characterize the plasma metabolome of PPGL patients before and after surgery, using an untargeted approach, and to broaden the scope of the investigated metabolic impact of these tumors. Design A cohort of 36 PPGL patients was investigated. Blood plasma samples were collected before and after surgical tumor removal, in association with clinical and tumor characteristics. Methods Plasma samples were analyzed using untargeted nuclear magnetic resonance (NMR) spectroscopy metabolomics. The data were evaluated using a combination of uni- and multi-variate statistical methods. Results Before surgery, patients with a nonadrenergic tumor could be distinguished from those with an adrenergic tumor based on their metabolic profiles. Tyrosine levels were significantly higher in patients with high compared to those with low BMI. Comparing subgroups of pre-operative samples with their post-operative counterparts, we found a metabolic signature that included ketone bodies, glucose, organic acids, methanol, dimethyl sulfone and amino acids. Three signals with unclear identities were found to be affected. Conclusions Our study suggests that the pathways of glucose and ketone body homeostasis are affected in PPGL patients. BMI-related metabolite levels were also found to be altered, potentially linking muscle atrophy to PPGL. At baseline, patient metabolomes could be discriminated based on their catecholamine phenotype.