Increased Resting-State Functional Connectivity in Patients With Autoimmune Addison Disease

CONTEXT

Individuals with autoimmune Addison disease (AAD) take replacement medication for the lack of adrenal-derived glucocorticoid (GC) and mineralocorticoid hormones from diagnosis. The brain is highly sensitive to these hormones, but the consequence of having AAD for brain health has not been widely addressed.

OBJECTIVE

The present study compared resting-state functional connectivity (rs-fc) of the brain between individuals with AAD and healthy controls.

METHODS

Fifty-seven patients with AAD (33 female) and 69 healthy controls (39 female), aged 19 to 43 years were scanned with 3-T magnetic resonance imaging (MRI).

RESULTS

Independent component and subsequent dual regression analyses revealed that individuals with AAD had stronger rs-fc compared to controls in 3 networks: the bilateral orbitofrontal cortex (OFC), the left medial visual and left posterior default mode network. A higher GC replacement dose was associated with stronger rs-fc in a small part of the left OFC in patients. We did not find any clear associations between rs-fc and executive functions or mental fatigue.

CONCLUSION

Our results suggest that having AAD affects the baseline functional organization of the brain and that current treatment strategies of AAD may be one risk factor.

An update on the long-term outcomes of prenatal dexamethasone treatment in congenital adrenal hyperplasia

First-trimester prenatal treatment with glucocorticoid (GC) dexamethasone (DEX) in pregnancies at risk for classic congenital adrenal hyperplasia (CAH) is associated with ethical dilemmas. Though effective in reducing virilisation in girls with CAH, it entails exposure to high doses of GC in fetuses that do not benefit from the treatment. The current paper provides an update on the literature on outcomes of prenatal DEX treatment in CAH cases and unaffected subjects. Long-term follow-up research is still needed to determine treatment safety. In addition, advances in early prenatal diagnostics for CAH and sex-typing as well as studies assessing dosing effects of DEX may avoid unnecessary treatment and improve treatment safety.

First Trimester Dexamethasone Treatment Is Not Associated With Alteration in Resting-state Connectivity at Adolescent or Adult Age

CONTEXT

Prenatal treatment with dexamethasone (DEX) has been used to prevent virilization in females at risk of congenital adrenal hyperplasia (CAH). Both affected and unaffected girls, as well boys, are treated until the genotype and sex of the fetus is known (gestational weeks 10-12). After that, only affected girls are treated until term. Exposure to a high synthetic glucocorticoid dosage may alter the developmental trajectory of the brain, with alterations in resting-state functional connectivity of the brain at adult age.

OBJECTIVE

To investigate resting-state functional connectivity in subjects at risk of having CAH, exposed to DEX treatment during the first trimester of fetal life, both in the whole brain and in 3 regions of interest (amygdala, hippocampus, and superior frontal gyrus).

DESIGN, SETTING, AND PARTICIPANTS

Eighteen participants (8 females) at risk of having CAH, exposed to DEX treatment, and 38 controls (24 females), age range 16 to 26 years, from a single research institute, underwent functional magnetic resonance imaging of the brain during rest. We used 2 different approaches: an exploratory whole-brain analysis and seed-based analysis. For seed-based analysis, we chose 3 different brain regions (amygdala, hippocampus, and superior frontal gyrus) based on our previous findings and literature evidence.

RESULTS

We did not observe any differences in functional connectivity during rest, either in the whole brain nor in seed-based connectivity analyses at this adolescent and young adult age.

CONCLUSIONS

Our results are reassuring; however, future studies on larger samples and with more sensitive methodologies are needed to confirm these findings.

First Trimester DEX Treatment Is Not Associated with Altered Brain Activity During Working Memory Performance in Adults

CONTEXT

Prenatal dexamethasone (DEX) treatment is sometimes used in pregnancies at risk for congenital adrenal hyperplasia (CAH) to prevent virilization in female fetuses with CAH. In boys and in fetuses not having CAH, there is no benefit of early DEX treatment and the risks of this therapy must be thoroughly investigated. High doses of prenatal glucocorticoid might alter the developmental trajectory of the brain into adulthood, even for CAH unaffected subjects treated with DEX for a short term during the first trimester.

OBJECTIVE

The present study investigated brain activation during working memory performance in DEX-treated subjects compared with controls.

DESIGN, SETTING, AND PARTICIPANTS

We tested 18 participants who were exposed to DEX during the first trimester of fetal life but did not have CAH (8 females; mean age 20.78 [standard deviation (SD), 2.67] years) and 40 control participants (24 females; mean age 20.53 [SD, 2.64]) from a single research institute. Participants underwent functional magnetic resonance imaging on a 3T scanner during a verbal and visuospatial working memory task.

RESULTS

We did not observe any differences in brain activity during working memory performance. However, DEX-treated subjects responded faster during the experimental condition of the verbal WM task.

CONCLUSIONS

First trimester DEX treatment did not seem to result in altered working memory-related brain activity at adult age. Our findings contribute to the risk-benefit assessment of prenatal DEX treatment in the context of CAH.

First-Trimester Prenatal Dexamethasone Treatment Is Associated With Alterations in Brain Structure at Adult Age

CONTEXT

Prenatal treatment of human disease is rare. Dexamethasone (DEX) is used in pregnancies at risk for congenital adrenal hyperplasia (CAH) to prevent virilization in an affected female fetus. The safety and long-term consequences of prenatal DEX exposure on the brain are largely unknown.

OBJECTIVE

We investigate whether first-trimester prenatal DEX treatment is associated with alterations in brain structure at adult age, and if these alterations are associated with DNA methylation, mood, and cognitive abilities.

DESIGN, SETTING, AND PARTICIPANTS

T1-weighted and diffusion-weighted imaging scans, from a single research institute, are compared between 19 (9 women) first-trimester DEX-treated individuals, at risk of CAH but not having CAH, and 43 (26 women) controls (age range, 16.0-26.4 years).

RESULTS

DEX-treated participants showed bilateral enlargement of the amygdala, increased surface area and volume of the left superior frontal gyrus, and widespread increased radial, mean, and axial diffusivity of white matter, in particular in the superior longitudinal fasciculi and corticospinal tracts. In the DEX-treated group, increased mean and radial diffusivity correlated with increased methylation of the promotor region of the FKBP5 gene. There were no group differences in cognition or in scales assessing depression or anxiety, and the relationship between brain structure and cognition did not differ between DEX-treated and controls.

CONCLUSIONS

First-trimester prenatal DEX treatment is associated with structural alterations of the brain at adult age, with an accompanying change in gene methylation. The findings add to the safety concerns of prenatal DEX treatment in the context of CAH.

Altered Gray Matter Structure and White Matter Microstructure in Patients with Congenital Adrenal Hyperplasia: Relevance for Working Memory Performance

Congenital adrenal hyperplasia (CAH) has been associated with brain structure alterations, but systematic studies are lacking. We explore brain morphology in 37 (21 female) CAH patients and 43 (26 female) healthy controls, aged 16–33 years, using structural magnetic resonance imaging to estimate cortical thickness, surface area, volume, subcortical volumes, and white matter (WM) microstructure. We also report data on a small cohort of patients (n = 8) with CAH, who received prenatal dexamethasone (DEX). Patients with CAH had reduced whole brain volume (4.23%) and altered structure of the prefrontal, parietal, and superior occipital cortex. Patients had reduced mean FA, and reduced RD and MD, but not after correcting for brain volume. The observed regions are hubs of the visuospatial working memory and default mode (DMN) networks. Thickness of the left superior parietal and middle frontal gyri was associated with visuospatial working memory performance, and patients with CAH performed worse on this task. Prenatal treatment with DEX affected brain structures in the parietal and occipital cortex, but studies in larger cohorts are needed. In conclusion, our study suggests that CAH is associated with brain structure alterations, especially in the working memory network, which might underlie the cognitive outcome observed in patients.