Brain metabolite abnormalities in ventromedial prefrontal cortex are related to duration of hypercortisolism and anxiety in patients with Cushing's syndrome

Neurochemical Anatomy of Cushing's Syndrome

The neurochemical anatomy underlying Cushing's syndrome is examined for regional brain metabolism as well as neurotransmitter levels and receptor binding of biogenic amines and amino acids. Preliminary studies generally indicate that glucose uptake, blood flow, and activation on fMRI scans decreased in neocortical areas and increased in subcortical areas of patients with Cushing's syndrome or disease. Glucocorticoid-mediated increases in hippocampal metabolism occurred despite in vitro evidence of glucocorticoid-induced decreases in glucose uptake or consumption, indicating that in vivo increases are the result of indirect, compensatory, or preliminary responses. In animal studies, glucocorticoid administration decreased 5HT levels and 5HT1A receptor binding in several brain regions while adrenalectomy increased such binding. Region-specific effects were also obtained in regard to the dopaminergic system, with predominant actions of glucocorticoid-induced potentiation of reuptake blockers and releasing agents. More in-depth neuroanatomical analyses are warranted of these and amino acid-related neurotransmission.

Hippocampal neurometabolic and structural changes from pre-to post-COVID-19: A case-series study

BACKGROUND

Neurological complications of the COVID-19 infection may be caused in part by local neurochemical and structural abnormalities that could not be detected during routine medical examinations. We examined within subject neurometabolic and structural brain alterations from pre-to post-COVID-19 in the hippocampal region of three elderly individuals (aged 63-68 years) who had a COVID-19 infection with mild symptoms. Patients were participating in an interventional study in which they were closely monitored at the time they were diagnosed with COVID-19. Patients 1 and 2 just completed 18-20 resistance training sessions prior to their diagnosis. Patient 3 was assigned to a non-training condition in the same study.

METHODS

Whole brain magnetic resonance imaging (MRI) images and proton magnetic resonance spectroscopy (1H-MRS) of the left hippocampus were collected before and after infection. Structural and spectroscopic imaging measures post-COVID-19 were contrasted to the pre-COVID-19 measures and were compared with values for Minimal Detectable Change at 95% (MDC95) and 90% (MDC90) confidence from a group of six elderly (aged 60-79 years) without COVID-19 that participated in the same study.

RESULTS

After SARS-COV-2 infection, we observed a reduction of glutamate-glutamine (Glx) in Patients 1 and 2 (≥ 42.0%) and elevation of myo-inositol (mIns) and N-acetyl-aspartate (NAA) in Patient 3 (≥ 36.4%); all > MDC90. MRI findings showed increased (Patients 1 and 2) or unchanged (Patient 3) hippocampal volume.

CONCLUSIONS

Overall, findings from this exploratory study suggest that mild COVID-19 infection could be associated with development of local neuroinflammation and reduced glutamate levels in the hippocampus. Our 1H-MRS findings may have clinical value for explaining chronic neurological and psychological complaints in COVID-19 long-haulers.

Glymphatic transport is reduced in rats with spontaneous pituitary tumor

Background and objective

Pituitary tumor in patients induces adverse alterations in the brain, accompanied by cognitive deficits. Dysfunction of glymphatic waste clearance results in accumulation of neurotoxic products within the brain, leading to cognitive impairment. However, the status of glymphatic function in the brain with pituitary tumor is unknown. Using magnetic resonance imaging (MRI) and an advanced mathematical modeling, we investigated the changes of glymphatic transport in the rats carrying spontaneous pituitary tumor.

Methods

Rats (22-24 months, female, Wistar) with and without pituitary tumor (n = 7/per group) underwent the identical experimental protocol. MRI measurements, including T2-weighted imaging and dynamic 3D T1-weighted imaging with intracisternal administration of contrast agent, were performed on each animal. The contrast-induced enhancement in the circle of Willis and in the glymphatic influx nodes were observed on the dynamic images and verified with time-signal-curves (TSCs). Model-derived parameters of infusion rate and clearance rate that characterize the kinetics of glymphatic tracer transport were evaluated in multiple representative brain regions.

Results

Our imaging data demonstrated a higher incidence of partially enhanced circle of Willis (86 vs. 14%; p < 0.033) and a lower incidence of enhancement in glymphatic influx nodes of pituitary (71 vs. 100%) and pineal (57 vs. 86%) recesses in the rats with pituitary tumor than in the rats with normal appearance of pituitary gland, indicating an intensification of impaired peri-vascular pathway and impeded glymphatic transport due to the presence of pituitary tumor. Consistently, our kinetic modeling and regional cerebral tissue quantification revealed significantly lower infusion and clearance rates in all examined regions in rats with spontaneous pituitary tumor than in non-tumor rats, representing a suppressed glymphatic transport in the brain with pituitary tumor.

Conclusion

Our study demonstrates the compromised glymphatic transport in the rat brain with spontaneous pituitary tumor. The reduced efficiency in cerebral waste clearance increases the risk for neurodegeneration in the brain that may underlie the cognitive impairment commonly seen in patients with pituitary tumors.

Long-term effects of glucocorticoid excess on the brain

The metabolic and cardiovascular clinical manifestations in patients with Cushing's syndrome (CS) are generally well known. However, recent studies have broadened the perspective of the effects of hypercortisolism, showing that both endogenous and exogenous glucocorticoid excess alter brain functioning on several time scales. Consequently, cognitive deficits and neuropsychological symptoms are highly prevalent during both active CS and CS in remission, as well as during glucocorticoid treatment. In this review, we discuss the effects of endogenous hypercortisolism and exogenously induced glucocorticoid excess on the brain, as well as the prevalence of cognitive and neuropsychological deficits and their course after biochemical remission. Furthermore, we propose possible mechanisms that may underly neuronal changes, based on experimental models and in vitro studies. Finally, we offer recommendations for future studies.

Metabolic profiling of serum from dogs with pituitary-dependent hyperadrenocorticism

Hyperadrenocorticism (HAC) is one of the most common endocrine diseases in dogs characterized by excessive cortisol production caused by an adrenocorticotropic hormone (ACTH)-secreting tumor, namely pituitary-dependent HAC (PDH) or cortisol-secreting adrenal tumor. Metabolomics presents the ability to identify small molecule metabolites. Thus, the use of metabolomics techniques in canine PDH can provide information about the pathophysiology and metabolic changes in this disease. This study aimed to identify and compare differences in serum metabolites between dogs with PDH and healthy dogs. The metabolomic profile of 20 dogs diagnosed with PDH was compared with 20 healthy dogs using liquid chromatography/mass spectrometry (LC/MS), and metabolite discrimination was performed using partial least squares-discriminant analysis (PLS-DA), the variable important in projection (VIP) and fold changes (FC) group-wise comparisons. The hypergeometric test identified the significantly altered pathways. A total of 21 metabolites were found to be significantly different between the two groups. The major alterations were found in arachidonic and decanoic acid, and phospholipids related to phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI). These metabolites are related to insulin resistance and other complications (i.e. hypertension). Our results indicate that PDH produces changes in serum metabolites of dogs, and the knowledge of these changes can aid to better understanding of pathophysiological processes involved and contribute to potentially detect new biomarkers for this disease.

Psychiatric and neurocognitive consequences of endogenous hypercortisolism

Psychiatric and neurocognitive symptoms due to hypercortisolism were already described by Harvey Cushing in his original paper on patients with Cushing's syndrome (CS). Nowadays, it is well known that psychiatric and cognitive complaints are two of the most common, and most distressing, symptoms in patients with CS. Psychiatric symptoms are indeed a major clinical manifestation of CS. The most commonly observed psychiatric conditions are depression and anxiety, whilst mania and psychosis are less common. Several domains of cognitive function are impaired at diagnosis, including episodic and working memory, executive function and attention. Following treatment, one-fourth of the patients still experience depressed mood, and the cognitive impairments are only partially restored. Consequently, quality of life in patients with CS is severely and persistently affected. Neuroimaging studies have also illustrated the deleterious effects of hypercortisolism on the brain by demonstrating reduced grey matter volumes and cortical thickness, altered resting-state functional responses and during cognitive tasks, as well as widespread reduced white matter integrity, especially in structures important for cognitive function and emotional processing, both before and after successful abrogation of hypercortisolism. In this paper, we summarize the current knowledge on the psychiatric and neurocognitive consequences of hypercortisolism in patients with CS, both before, and after successful treatment. In addition, we review the structural and functional brain abnormalities associated with hypercortisolism and discuss the influence of these factors on quality of life.

Metabolomic Biomarkers in Anxiety Disorders

Anxiety disorders range among the most prevalent psychiatric disorders and belong to the leading disorders in the study of the total global burden of disease. Anxiety disorders are complex conditions, with not fully understood etiological mechanisms. Numerous factors, including psychological, genetic, biological, and chemical factors, are thought to be involved in their etiology. Although the diagnosis of anxiety disorders is constantly evolving, diagnostic manuals rely on symptom lists, not on objective biomarkers and treatment effects are small to moderate. The underlying biological factors that drive anxiety disorders may be better suited to serve as biomarkers for guiding personalized medicine, as they are objective and can be measured externally. Therefore, the incorporation of novel biomarkers into current clinical methods might help to generate a classification system for anxiety disorders that can be linked to the underlying dysfunctional pathways. The study of metabolites (metabolomics) in a large-scale manner shows potential for disease diagnosis, for stratification of patients in a heterogeneous patient population, for monitoring therapeutic efficacy and disease progression, and for defining therapeutic targets. All of these are important properties for anxiety disorders, which is a multifactorial condition not involving a single-gene mutation. This review summarizes recent investigations on metabolomics studies in anxiety disorders.

Reversibility of cerebral blood flow in patients with Cushing's disease after surgery treatment

BACKGROUND AND OBJECTIVES

Cushing's disease (CD) patients have metabolic abnormalities in the brain caused by excessive exposure to endogenous cortisol. However, the reversibility of brain metabolism of CD patients after treatment remains largely unknown.

METHODS

This study recruited 50 CD patients seeking treatment and 34 matched normal controls (NCs). The patients were treated with Transsphenoidal Adenomectomy (TSA) and reexamined 3 months later. Cerebral blood flow (CBF) of the patients was assessed using 3D pseudo-continuous arterial spin labelling (PCASL) imaging before the treatment and at the 3-month follow-up and were compared with CBF measure of the NCs using a whole-brain voxelwise group comparison method. For remitted patients, their CBF measures and hormone level measures, including adrenocorticotropic hormone (ACTH), 24-hour urinary free cortisol (24hUFC) and serum cortisol, were compared before and after the treatment. Finally, a correlation analysis was carried out to explore the relationship between changes of CBF and hormone level measures of the remitted CD patients.

RESULTS

After the treatment, 45 patients reached remission. Compared with the NCs, the CD patients before the treatment exhibited significantly reduced CBF in cortical regions, including occipital lobe, parietal lobe, superior/middle/inferior temporal gyrus, superior/middle/inferior frontal gyrus, orbitofrontal cortex, precentral gyrus, middle/posterior cingulate gyrus, and rolandic operculum, as well as significantly increased CBF in subcortical structures, including caudate, pallidum, putamen, limbic lobe, parahippocampal gyrus, hippocampus, thalamus, and amygdala (p < 0.01, false discovery rate corrected). For the remitted patients, the change in CBF before and after the treatment displayed a spatial pattern similar to the difference between the NCs and the CD patients before the treatment, and no significant difference in CBF was observed between the NCs and the remitted CD patients after the treatment. The changes of 24hUFC were significantly correlated with the changes of averaged CBF within the subcortical region in the remitted patients (p = 0.01).

CONCLUSIONS

Our findings demonstrate that the brain metabolic abnormalities of CD patients are reversible when their hormone level changes towards normal after surgery treatment.

Dynamic changes of views on the brain changes of Cushing's syndrome using different computer-assisted tool

Cushing's syndrome (CS) provides a unique model for assessing the neurotoxic effect of chronic hypercortisolism on human brains. With the ongoing development of different computer-assisted tools, four research stages emerged, each with its own pearls and pitfalls. This review summarizes current knowledge and describes the dynamic changes of views on the brain changes of CS, especially in the current era of the rapid development of artificial intelligence and big data. The adverse effects of GC on brain are proven to be on structural, functional and cellular levels at the same time.

Reversible and the irreversible structural alterations on brain after resolution of hypercortisolism in Cushing's disease

The adverse effects of hypercortisolism on the human brain have been highlighted in previous studies of Cushing's disease (CD). However, the reversibility of brain damage after the resolution of hypercortisolism remains unclear. Thus, we studied the potential volumetric reversibility in biochemically remitted CD patients. Cross-sectional analysis demonstrated the active CD patients (n = 61) had the smallest gray matter (GM) volumes (553.33 ± 45.90 CM³) among four groups. While the GM volumes of short-term remitted CD patients (586.62 ± 46.89 CM³, n = 28) and long-term remitted CD patients (596.58 ± 45.95 CM³, n = 35) were between those of the active CD patients and healthy control subjects (628.14 ± 46.88 CM³, n = 74). Moreover, significant positive correlations between remitted time and GM volumes were only found in short-term remitted CD patients. On the contrary, the alterations of white matter (WM) in CD patients seem to be independent of concomitant hypercortisolism, persisting after remission. A preliminary longitude analysis also demonstrated similar results. Volumetric reversibility of GM, but not WM is highly prevalent in short-term after resolution of hypercortisolism in Cushing disease. Our study enhances our understanding of the reversible and the irreversible structural alterations in the human brain due to hypercortisolism.

Improvement in cognitive impairment following the successful treatment of endogenous Cushing's syndrome-a case report and literature review

BACKGROUND

Endogenous Cushing's syndrome, a rare endocrine disorder, characterised by chronic cortisol hypersecretion, results in neuropsychiatric disturbances and in cognitive deficits, which are only partially reversible after the biochemical remission of the disease.

CASE PRESENTATION

We report a case of a woman with a profound cognitive deficit and a gradual functional decline caused by Cushing's disease of at least 10 years duration. The neurosurgical resection of her 2 mm adrenocorticotropic hormone (ACTH) secreting pituitary microadenoma resulted in a successful resolution of the patient's hypercortisolism and a significant recovery of her neurocognitive function. The patient's progress was evaluated using serial clinical observations, functional assessments, Mini-Mental Status exams and through the formal neuropsychological report. Furthermore, the patient's recovery of her neurocognitive function was reflected by a sustained improvement in the patient's specific structural brain abnormalities on radiological imaging.

CONCLUSIONS

This report illustrates the importance of early detection and treatment of Cushing's syndrome in order to prevent neurocognitive impairment and neuropsychiatric disorders which are associated with an endogenous cortisol hypersecretion. The long term adverse effects of severe hypercortisolaemia on brain function and the pathophysiological mechanisms responsible for the structural and functional changes in brain anatomy due to glucocorticoid excess are reviewed.

Quality of Life in Patients With Cushing's Disease

Cushing's disease (and by extension, Cushing's syndrome) is a rare disease due to a chronic cortisol excess, which usually has an important impact on quality of life (QoL). It can lead to numerous comorbidities that can interfere with daily life, as fatigability, myopathy, bone loss and fragility, increased cardiovascular risk, depression, and cognitive alterations. Of note, psychological alterations (including depression and anxiety) occur often, and are an important determinant of impaired quality QoL. QoL scores using different questionnaires are poorer in comparison to healthy controls, other pituitary adenomas and some chronic diseases. Even if some improvements can be observed after successful treatment, recovery does not seem to be complete, and comorbidities persist. This persistent QoL impairment has been found using both generic and disease-specific QoL questionnaires, and is also reported by the patients themselves, when asked directly. Multidisciplinary teams are essential to improve patients' well-being. Clinicians should take into account the whole scope of clinical problems and address the different comorbidites associated with the disease. Screening in the psychological sphere, with further intervention if necessary, can be helpful in the management of these patients. Interventions and programs have shown promising results, although there is a need for further development of new strategies for the benefit of these patients.

Structural brain abnormalities in Cushing's syndrome

PURPOSE OF REVIEW

Alongside various physical symptoms, patients with Cushing's disease and Cushing's syndrome display a wide variety of neuropsychiatric and cognitive symptoms, which are indicative of involvement of the central nervous system. The aim of this review is to provide an overview of the structural brain abnormalities that are associated with Cushing's disease and Cushing's syndrome and their relation to behavioral and cognitive symptomatology.

RECENT FINDINGS

In this review, we discuss the gray matter structural abnormalities found in patients with active Cushing's disease and Cushing's syndrome, the reversibility and persistence of these changes and the white matter structural changes related to Cushing's syndrome. Recent findings are of particular interest because they provide more detailed information on localization of the structural changes as well as possible insights into the underlying biological processes.

SUMMARY

Active Cushing's disease and Cushing's syndrome is related to volume reductions of the hippocampus and in a prefrontal region involving the anterior cingulate cortex (ACC) and medial frontal gyrus (MFG). Whilst there are indications that the reductions in hippocampal volume are partially reversible, the changes in the ACC and MFG appear to be more persistent. In contrast to the volumetric findings, changes in white matter connectivity are typically widespread involving multiple tracts.

Dietary Acid Load and Mental Health Outcomes in Children and Adolescents: Results from the GINIplus and LISA Birth Cohort Studies

High dietary acid load may have detrimental effects on mental health during childhood and adolescence. We examined cross-sectional and prospective associations of dietary acid load and mental health problems in a population-based sample, using data from the German birth cohort studies GINIplus (German Infant Nutritional Intervention plus environmental and genetic influences on allergy development) and LISA (Influences of lifestyle-related factors on the immune system and the development of allergies in childhood). These studies included detailed assessments of dietary intake through a food frequency questionnaire (FFQ), mental health outcomes measured through the Strengths and Difficulties Questionnaire (SDQ), and covariates. Using logistic regression, cross-sectional associations between dietary acid load measured as potential renal acid load (PRAL) and SDQ subscales were assessed at age 10 years (N = 2350) and 15 years (N = 2061). Prospective associations were assessed, considering PRAL at 10 years as exposure and SDQ subscales at 15 years as outcome (N = 1685). Results indicate that children with a diet higher in PRAL have more emotional problems (OR = 1.33 (95% CI = 1.15; 1.54); p < 0.001), and show hyperactivity more often (1.22 (1.04; 1.43); p = 0.014) at 10 years. No significant associations were present either cross-sectionally at age 15 years, nor prospectively. Results were confirmed in sensitivity analyses. These findings reveal first evidence for potential relationships between PRAL and mental health in childhood, although we cannot exclude reverse causality, i.e., that dietary behavior and PRAL are influenced by mental status. Future studies should address confirmation and identify biological mechanisms.

Volumetric magnetic resonance imaging analysis in patients with short-term remission of Cushing's disease

OBJECTIVE

The data on patients with short-term remission of Cushing's disease (CD) might provide information that is not available from previous long-term remission studies. We aimed to investigate structural changes in the brain in these patients and to examine whether these changes were associated with clinical characteristics.

DESIGN

A cross-sectional study was performed.

METHODS

Thirty-four patients with CD (14 with CD in short-term remission and 20 with active CD) and 34 controls matched for age, sex and education underwent clinical evaluation and magnetic resonance imaging brain scans. Biometric measurements, disease duration and remission duration data were collected. Grey matter volumes in the whole brain were examined using voxel-based morphometry (VBM).

RESULTS

No differences were observed in the grey matter volumes of the medial frontal gyrus (MFG) and cerebellum between the patients with remitted CD and healthy controls, whereas patients with active CD had smaller grey matter volumes in these two regions compared with controls and patients with remitted CD. Furthermore, significant correlations were found between remission time and grey matter values in these regions in short-term remission patients with CD. Additionally, greater grey matter volumes in the bilateral caudate of short-term remission patients with CD were observed.

CONCLUSIONS

Trends for structural restoration were found in CD patients with short-term remission. This finding was associated with the number of days elapsed since curative surgery and the current age of the patients. This study enhances our understanding of potential reversibility after the resolution of hypercortisolism in CD patients.

White matter involvement on DTI-MRI in Cushing's syndrome relates to mood disturbances and processing speed: a case-control study

PURPOSE

Cushing's syndrome (CS) is an endocrine disorder due to prolonged exposure to cortisol. Recently, microstructural white matter (WM) alterations detected by diffusion tensor imaging (DTI) have been reported in CS patients, and related to depression, but other functional significances. remain otherwise unclear. We aimed at investigating in more depth mood symptoms in CS patients, and how these relate to cognition (information processing speed), and to WM alterations on DTI.

METHODS

The sample comprised 35 CS patients and 35 healthy controls. Beck Depression Inventory-II (BDI-II) was used to measure depressive symptoms, State-Trait Anxiety Inventory (STAI) to assess anxiety, and processing speed was measured by the Symbol Digit Modalities Test (SDMT). DTI studies were acquired using a 3-Tesla Philips-Achieva MR-facility. Voxelwise statistical analysis of fractional anisotropy (FA), mean, axial and radial diffusivities (MD, AD, RD) data were performed using FMRIB Software Library. Correlation analysis were obtained between mood and processing speed variables, and FA, MD, AD and RD values, taking both CS patients and healthy controls.

RESULTS

Active, controlled and cured CS patients showed greater depression (F = 12.4, p < 0.001), anxious state (F = 4.8, p = 0.005) and anxious trait (F = 9.6, p < 0.001) scores, than controls. Using the entire sample, depression scores correlated negatively to FA and positively to RD values. Although there were no differences in processing speed between groups, SDMT scores correlated positively to both FA and AD values.

CONCLUSIONS

There were greater depressive and anxious symptoms in CS patients than in healthy controls, but no difference in processing speed. However, DTI is related to depression and information processing speed in CS.