Cortical thickness abnormalities in long-term remitted Cushing's disease

Long-Term Consequences of Cushing Syndrome: A Systematic Literature Review

It is held that the condition of endogenous chronic hypersecretion of cortisol (Cushing syndrome, CS), causes several comorbidities, including cardiovascular and metabolic disorders, musculoskeletal alterations, as well as cognitive and mood impairment. Therefore, CS has an adverse impact on the quality of life and life expectancy of affected patients. What remains unclear is whether disease remission may induce a normalization of the associated comorbid conditions. In order to retrieve updated information on this issue, we conducted a systematic search using the Pubmed and Embase databases to identify scientific papers published from January 1, 2000, to December 31, 2022. The initial search identified 1907 potentially eligible records. Papers were screened for eligibility and a total of 79 were included and classified by the main topic (cardiometabolic risk, thromboembolic disease, bone impairment, muscle damage, mood disturbances and quality of life, cognitive impairment, and mortality). Although the limited patient numbers in many studies preclude definitive conclusions, most recent evidence supports the persistence of increased morbidity and mortality even after long-term remission. It is conceivable that the degree of normalization of the associated comorbid conditions depends on individual factors and characteristics of the conditions. These findings highlight the need for early recognition and effective management of patients with CS, which should include active treatment of the related comorbid conditions. In addition, it is important to maintain a surveillance strategy in all patients with CS, even many years after disease remission, and to actively pursue specific treatment of comorbid conditions beyond cortisol normalization.

Comparison of two corticosteroid regimens on brain volumetrics in patients with Duchenne muscular dystrophy

OBJECTIVE

Duchenne muscular dystrophy (DMD) is a neuromuscular disorder in which many patients also have neurobehavioral problems. Corticosteroids, the primary pharmacological treatment for DMD, have been shown to affect brain morphology in other conditions, but data in DMD are lacking. This study aimed to investigate the impact of two corticosteroid regimens on brain volumetrics in DMD using magnetic resonance imaging (MRI).

METHODS

In a cross-sectional, two-center study, T1-weighted MRI scans were obtained from three age-matched groups (9-18 years): DMD patients treated daily with deflazacort (DMDd, n = 20, scan site: Leuven), DMD patients treated intermittently with prednisone (DMDi, n = 20, scan site: Leiden), and healthy controls (n = 40, both scan sites). FSL was used to perform voxel-based morphometry analyses and to calculate intracranial, total brain, gray matter, white matter, and cerebrospinal fluid volumes. A MANCOVA was employed to compare global volumetrics between groups, with site as covariate.

RESULTS

Both patient groups displayed regional differences in gray matter volumes compared to the control group. The DMDd group showed a wider extent of brain regions affected and a greater difference overall. This was substantiated by the global volume quantification: the DMDd group, but not the DMDi group, showed significant differences in gray matter, white matter, and cerebrospinal fluid volumes compared to the control group, after correction for intracranial volume.

INTERPRETATION

Volumetric differences in the brain are considered part of the DMD phenotype. This study suggests an additional impact of corticosteroid treatment showing a contrast between pronounced alterations seen in patients receiving daily corticosteroid treatment and more subtle differences in those treated intermittently.

Reversibility of Impaired Large-Scale Functional Brain Networks in Cushing's Disease after Surgery Treatment: A Longitudinal Study

INTRODUCTION

Chronic exposure to excessive endogenous cortisol leads to brain changes in Cushing's disease (CD). However, it remains unclear how CD affects large-scale functional networks (FNs) and whether these effects are reversible after treatment. This study aimed to investigate functional network changes of CD patients and their reversibility in a longitudinal cohort.

METHODS

Active CD patients (N = 37) were treated by transsphenoidal pituitary surgery and reexamined 3 months later. FNs were computed from resting-state fMRI data of the CD patients and matched normal controls (NCs, N = 37). A pattern classifier was built on the FNs to distinguish active CD patients from controls and applied to FNs of the CD patients at the 3-month follow-up. Two subgroups of endocrine-remitted CD patients were identified according to their classification scores, referred to as image-based phenotypically (IBP) recovered and unrecovered CD patients, respectively. The informative FNs identified by the classification model were compared between NCs, active CD patients, and endocrine-remitted patients as well as between IBP recovered and unrecovered CD patients to explore their functional network reversibility.

RESULTS

All 37 CD patients reached endocrine remission after treatment. The classification model identified three informative FNs, including cerebellar network (CerebN), fronto-parietal network (FPN), and default mode network. Among them, CerebN and FPN partially recovered toward normal at 3 months after treatment. Moreover, the informative FNs were correlated with 24-h urinary-free cortisol and emotion scales in CD patients.

CONCLUSION

These findings suggest that CD patients have aberrant FNs that are partially reversible toward normal after treatment.

Dynamic functional connectivity changes associated with psychiatric traits and cognitive deficits in Cushing's disease

Cushing's disease is a rare neuroendocrine disorder with excessive endogenous cortisol, impaired cognition, and psychiatric symptoms. Evidence from resting-state fMRI revealed the abnormalities of static brain connectivity in patients with Cushing's disease (CD patients). However, it is unknown whether the CD patients' dynamic functional connectivity would be abnormal and whether the dynamic features are associated with deficits in cognition and psychopathological symptoms. Here, we evaluated 50 patients with Cushing's disease and 57 healthy participants by using resting-state fMRI and dynamic functional connectivity (dFNC) approach. We focused on the dynamic features of default mode network (DMN), salience network (SN), and central executive network (CEN) because these are binding sites for the cognitive-affective process, as well as vital in understanding the pathophysiology of psychiatric disorders. The dFNC was further clustered into four states by k-mean clustering. CD patients showed more dwell time in State 1 but less time in State 4. Intriguingly, group differences in dwell time in these two states can explain the cognitive deficits of CD patients. Moreover, the inter-network connections between DMN and SN and the engagement time in State 4 negatively correlated with anxiety and depression but positively correlated with cognitive performance. Finally, the classifier trained by the dynamic features of these networks successfully classified CD patients from healthy participants. Together, our study revealed the dynamic features of CD patients' brains and found their associations with impaired cognition and emotional symptoms, which may open new avenues for understanding the cognitive and affective deficits induced by Cushing's disease.

Glucocorticoids and cognitive function: a walkthrough in endogenous and exogenous alterations

PURPOSE

The hypothalamic-pituitary-adrenal (HPA) axis exerts many actions on the central nervous system (CNS) aside from stress regulation. Glucocorticoids (GCs) play an important role in affecting several cognitive functions through the effects on both glucocorticoid (GR) and mineralocorticoid receptors (MR). In this review, we aim to unravel the spectrum of cognitive dysfunction secondary to derangement of circulating levels of endogenous and exogenous glucocorticoids.

METHODS

All relevant human prospective and retrospective studies published up to 2022 in PubMed reporting information on HPA disorders, GCs, and cognition were included.

RESULTS

Cognitive impairment is commonly found in GC-related disorders. The main brain areas affected are the hippocampus and pre-frontal cortex, with memory being the most affected domain. Disease duration, circadian rhythm disruption, circulating GCs levels, and unbalanced MR/GR activation are all risk factors for cognitive decline in these patients, albeit with conflicting data among different conditions. Lack of normalization of cognitive dysfunction after treatment is potentially attributable to GC-dependent structural brain alterations, which can persist even after long-term remission.

CONCLUSION

The recognition of cognitive deficits in patients with GC-related disorders is challenging, often delayed, or mistaken. Prompt recognition and treatment of underlying disease may be important to avoid a long-lasting impact on GC-sensitive areas of the brain. However, the resolution of hormonal imbalance is not always followed by complete recovery, suggesting irreversible adverse effects on the CNS, for which there are no specific treatments. Further studies are needed to find the mechanisms involved, which may eventually be targeted for treatment strategies.

Association between use of systemic and inhaled glucocorticoids and changes in brain volume and white matter microstructure: a cross-sectional study using data from the UK Biobank

OBJECTIVE

To test the hypothesis that systemic and inhaled glucocorticoid use is associated with changes in grey matter volume (GMV) and white matter microstructure.

DESIGN

Cross-sectional study.

SETTING

UK Biobank, a prospective population-based cohort study of adults recruited in the UK between 2006 and 2010.

PARTICIPANTS

After exclusion based on neurological, psychiatric or endocrinological history, and use of psychotropic medication, 222 systemic glucocorticoid users, 557 inhaled glucocorticoid users and 24 106 controls with available T1 and diffusion MRI data were included.

MAIN OUTCOME MEASURES

Primary outcomes were differences in 22 volumetric and 14 diffusion imaging parameters between glucocorticoid users and controls, determined using linear regression analyses adjusted for potential confounders. Secondary outcomes included cognitive functioning (six tests) and emotional symptoms (four questions).

RESULTS

Both systemic and inhaled glucocorticoid use were associated with reduced white matter integrity (lower fractional anisotropy (FA) and higher mean diffusivity (MD)) compared with controls, with larger effect sizes in systemic users (FA: adjusted mean difference (AMD)=-3.7e-3, 95% CI=-6.4e-3 to 1.0e-3; MD: AMD=7.2e-6, 95% CI=3.2e-6 to 1.1e-5) than inhaled users (FA: AMD=-2.3e-3, 95% CI=-4.0e-3 to -5.7e-4; MD: AMD=2.7e-6, 95% CI=1.7e-7 to 5.2e-6). Systemic use was also associated with larger caudate GMV (AMD=178.7 mm³, 95% CI=82.2 to 275.0), while inhaled users had smaller amygdala GMV (AMD=-23.9 mm³, 95% CI=-41.5 to -6.2) than controls. As for secondary outcomes, systemic users performed worse on the symbol digit substitution task (AMD=-0.17 SD, 95% CI=-0.34 to -0.01), and reported more depressive symptoms (OR=1.76, 95% CI=1.25 to 2.43), disinterest (OR=1.84, 95% CI=1.29 to 2.56), tenseness/restlessness (OR=1.78, 95% CI=1.29 to 2.41), and tiredness/lethargy (OR=1.90, 95% CI=1.45 to 2.50) compared with controls. Inhaled users only reported more tiredness/lethargy (OR=1.35, 95% CI=1.14 to 1.60).

CONCLUSIONS

Both systemic and inhaled glucocorticoid use are associated with decreased white matter integrity and limited changes in GMV. This association may contribute to the neuropsychiatric side effects of glucocorticoid medication, especially with chronic use.

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.

Increased medial prefrontal cortical thickness and resilience to traumatic experiences in North Korean refugees

Little is known regarding structural brain changes in traumatized refugees and the association with psychopathology. In the present study, the cortical thickness in North Korean refugees and the association with psychological symptoms were explored. North Korean refugees with lifetime post-traumatic stress disorder (PTSD group, n = 27), trauma-exposed North Korean refugees without lifetime PTSD (trauma-exposed control (TEC) group, n = 23), and healthy South Korean controls without traumatic experiences (HC group, n = 51) completed questionnaires assessing depression, anxiety, somatization, and PTSD symptoms. The cortical thickness was measured by magnetic resonance imaging (MRI) using FreeSurfer. Age- and sex-adjusted cortical thickness of the right medial prefrontal cortex (mPFC) was greater in the TEC group than in the HC group. However, significant differences were not observed between the PTSD and HC groups. Increased right mPFC thickness was significantly correlated with less anxiety and somatization after controlling for age and sex in the TEC group, but not in the PTSD or HC groups. North Korean refugees who did not develop PTSD after trauma showed increased right mPFC thickness, which was associated with less severe psychiatric symptoms. These findings indicate that increased mPFC thickness might have helped to reduce PTSD and psychiatric symptoms after trauma, and likely reflects resilience achieved by potentially enhancing emotional regulation in the mPFC.

Effects of Long-Term Endogenous Corticosteroid Exposure on Brain Volume and Glial Cells in the AdKO Mouse

Chronic exposure to high circulating levels of glucocorticoids has detrimental effects on health, including metabolic abnormalities, as exemplified in Cushing’s syndrome (CS). Magnetic resonance imaging (MRI) studies have found volumetric changes in gray and white matter of the brain in CS patients during the course of active disease, but also in remission. In order to explore this further, we performed MRI-based brain volumetric analyses in the AdKO mouse model for CS, which presents its key traits. AdKO mice had reduced relative volumes in several brain regions, including the corpus callosum and cortical areas. The medial amygdala, bed nucleus of the stria terminalis, and hypothalamus were increased in relative volume. Furthermore, we found a lower immunoreactivity of myelin basic protein (MBP, an oligodendrocyte marker) in several brain regions but a paradoxically increased MBP signal in the male cingulate cortex. We also observed a decrease in the expression of glial fibrillary acidic protein (GFAP, a marker for reactive astrocytes) and ionized calcium-binding adapter molecule 1 (IBA1, a marker for activated microglia) in the cingulate regions of the anterior corpus callosum and the hippocampus. We conclude that long-term hypercorticosteronemia induced brain region-specific changes that might include aberrant myelination and a degree of white matter damage, as both repair (GFAP) and immune (IBA1) responses are decreased. These findings suggest a cause for the changes observed in the brains of human patients and serve as a background for further exploration of their subcellular and molecular mechanisms.