Subclinical hypercortisolism (SH), defined as alterations of the hypothalamus–pituitary–adrenal axis in the absence of clinical signs or symptoms related to cortisol secretion, is a common finding in patients with adrenal incidentalomas. The clinical correlates of this pathological condition have become clearer over the last few years. The aim of this review is to summarize the co-morbidities and the clinical outcomes of patients with SH. According to the analysis of the results of the studies published within the last 15 years, hypertension and type 2 diabetes are a common finding in patients with SH, occurring roughly in 2/3 and 1/3 of the patients respectively. Moreover, several additional cardiovascular and metabolic complications, like endothelial damage, increased visceral fat accumulation and impaired lipid metabolism have been shown to increase the cardiovascular risk of those patients. Accordingly, recent independent reports investigating the natural history of the disease in a long-term follow-up setting have shown that patients with SH have a higher incidence of cardiovascular events and related mortality. Moreover, longitudinal studies have also shown increased incidence of osteoporotic vertebral fractures. Future research is needed to improve the diagnostic performance of hormonal tests, by assessment of the complete steroid profile with more accurate assays, and to define the efficacy of surgical vs medical treatment in a randomized-controlled setting.
Guido Di Dalmazi, Renato Pasquali, Felix Beuschlein and Martin Reincke
Davide Calebiro, Guido Di Dalmazi, Kerstin Bathon, Cristina L Ronchi and Felix Beuschlein
The cAMP signaling pathway is one of the major players in the regulation of growth and hormonal secretion in adrenocortical cells. Although its role in the pathogenesis of adrenocortical hyperplasia associated with Cushing's syndrome has been clarified, a clear involvement of the cAMP signaling pathway and of one of its major downstream effectors, the protein kinase A (PKA), in sporadic adrenocortical adenomas remained elusive until recently. During the last year, a report by our group and three additional independent groups showed that somatic mutations of PRKACA, the gene coding for the catalytic subunit α of PKA, are a common genetic alteration in patients with Cushing's syndrome due to adrenal adenomas, occurring in 35–65% of the patients. In vitro studies revealed that those mutations are able to disrupt the association between catalytic and regulatory subunits of PKA, leading to a cAMP-independent activity of the enzyme. Despite somatic PRKACA mutations being a common finding in patients with clinically manifest Cushing's syndrome, the pathogenesis of adrenocortical adenomas associated with subclinical hypercortisolism seems to rely on a different molecular background. In this review, the role of cAMP/PKA signaling in the regulation of adrenocortical cell function and its alterations in cortisol-producing adrenocortical adenomas will be summarized, with particular focus on recent developments.
Guido Di Dalmazi, Valentina Vicennati, Eleonora Rinaldi, Antonio Maria Morselli-Labate, Emanuela Giampalma, Cristina Mosconi, Uberto Pagotto and Renato Pasquali
Subclinical Cushing's syndrome (SCS) is defined as alterations in hypothalamic–pituitary–adrenal axis without classic signs/symptoms of glucocorticoid excess. Whether SCS leads to metabolic and cardiovascular diseases is still controversial.
To evaluate the prevalence of hypertension, type 2 diabetes (T2D), coronary heart disease (CHD), ischemic stroke, osteoporosis, and fractures, and their relationship to increasing patterns of subclinical hypercortisolism, in patients with nonsecreting adrenal adenomas (NSA) and SCS.
Using the 1 mg dexamethasone suppression test (DST), 348 patients were classified as follows: 203 were defined as NSA and 19 SCS, using the most stringent cutoff values (<50 and >138 nmol/l respectively). Patients with cortisol post-DST (50–138 nmol/l) were considered as intermediate phenotypes and classified as minor (n=71) and major (n=55) using plasma ACTH and/or urinary free cortisol as additional diagnostic tools.
SCS patients showed higher prevalence of T2D, CHD, osteoporosis, and fractures with respect to NSA. Intermediate phenotypes also showed higher prevalence of CHD and T2D with respect to NSA. The prevalence of all clinical outcomes was not different between intermediate phenotype patients, which were therefore considered as a single group (IP) for multivariate logistic regression analysis: both IP and SCS-secreting patterns showed a significant association with CHD (odds ratio (OR), 4.09; 95% confidence interval (CI), 1.47–11.38 and OR, 6.10; 95% CI, 1.41–26.49 respectively), independently of other potential risk factors. SCS was also independently associated with osteoporosis (OR, 5.94; 95% CI, 1.79–19.68).
Patterns of increasing subclinical hypercortisolism in adrenal adenomas are associated with increased prevalence of adverse metabolic and cardiovascular outcomes, independently of other potential risk factors.
Guido Di Dalmazi, Marcus Quinkler, Timo Deutschbein, Cornelia Prehn, Nada Rayes, Matthias Kroiss, Christina M Berr, Günter Stalla, Martin Fassnacht, Jerzy Adamski, Martin Reincke and Felix Beuschlein
Endogenous hypercortisolism is a chronic condition associated with severe metabolic disturbances and cardiovascular sequela. The aim of this study was to characterize metabolic alterations in patients with different degrees of hypercortisolism by mass-spectrometry-based targeted plasma metabolomic profiling and correlate the metabolomic profile with clinical and hormonal data.
Subjects (n = 149) were classified according to clinical and hormonal characteristics: Cushing’s syndrome (n = 46), adrenocortical adenomas with autonomous cortisol secretion (n = 31) or without hypercortisolism (n = 27). Subjects with suspicion of hypercortisolism, but normal hormonal/imaging testing, served as controls (n = 42). Clinical and hormonal data were retrieved for all patients and targeted metabolomic profiling was performed.
Patients with hypercortisolism showed lower levels of short-/medium-chain acylcarnitines and branched-chain and aromatic amino acids, but higher polyamines levels, in comparison to controls. These alterations were confirmed after excluding diabetic patients. Regression models showed significant correlation between cortisol after dexamethasone suppression test (DST) and 31 metabolites, independently of confounding/contributing factors. Among those, histidine and spermidine were also significantly associated with catabolic signs and symptoms of hypercortisolism. According to an discriminant analysis, the panel of metabolites was able to correctly classify subjects into the main diagnostic categories and to distinguish between subjects with/without altered post-DST cortisol and with/without diabetes in >80% of the cases.
Metabolomic profiling revealed alterations of intermediate metabolism independently associated with the severity of hypercortisolism, consistent with disturbed protein synthesis/catabolism and incomplete β-oxidation, providing evidence for the occurrence of metabolic inflexibility in hypercortisolism.