Adrenal gland size in obstructive sleep apnea: Morphological assessment of hypothalamic pituitary adrenal axis activity

Adrenal gland volume measurement in depressed patients

PURPOSE

Prior studies have shown contradicting results regarding adrenal gland volume (AGV) in depressed patients, with some reporting significant enlargement and others not. The aim of this study was to retrospectively compare CT image segmentations of the adrenal glands in patients with depression to a control group with stringent exclusion criteria to minimize confounding factors.

METHODS

We included patients diagnosed with depression (ICD-10: F32/33) who underwent abdominal CT imaging between 2012 and 2022 and did not have any other psychiatric disorders. Diagnoses that could potentially influence AGV were excluded. The resulting 31 depressed patients were compared to a matching control group of 31 patients without depression. The AGV was manually segmented in thin-sliced reconstructions (≤1 mm).

RESULTS

Total AGV in the depressed group was 6.78 (5.19-7.56) cm3 compared to 6.90 (5.54-10.05) cm3 in the control group. There was no significant difference in AGV between the two groups after adjusting for age, height, and weight. A positive correlation was observed between AGV and height (r = 0.41, p < 0.001) and weight (r = 0.52, p < 0.001). Males showed significantly larger AGV than females (p ≤ 0.001), and left AGV was significantly larger than right AGV (p < 0.001). Patients within the depressed group who underwent imaging after a suicide attempt showed larger total AGV compared to the control group, though not statistically significant.

CONCLUSION

AGV is not increased in the well-selected cohort of depressed patients in this study, which contrasts with some previous reports in literature. Further multi-centric studies are required to identify potentially influencing factors such as attempted suicide.

Genetic overlap between major depressive disorder and obstructive sleep apnea

Objective

Observational studies have frequently shown a co-occurrence of psychiatric disorders and Obstructive sleep apnea (OSA), with major depressive disorder (MDD) being a prevalent psychiatric disorder. This study aims to investigate the genetic overlap between MDD and OSA to explore their underlying pathological mechanisms.

Methods

Leveraging the extensive and recent GWAS for OSA and MDD, we conducted genetic correlation analyses utilizing Linkage disequilibrium score regression (LDSC), re-evaluated their pleiotropic Single-nucleotide polymorphisms (SNP) with Cross-Phenotype Association (CPASSOC) and Colocalization (COLOC), investigated the overlap at the gene level using physical annotations and Multi-marker Analysis of GenoMic Annotation (MAGMA), and finally employed Mendelian randomization (MR) to assess potential causal relationships between the two disorders.

Results

Upon our investigation, we established that MDD and OSA exhibit high heritability (h2MDD=0.02, h2OSA=0.04) alongside a significant genetic correlation (rg=0.31, P= 1.42E-23). Utilizing CPASSOC, we identified 397 pleiotropic SNPs, associable with 45 loci, two of which share common genetic fragments with a pleiotropic role. Furthermore, the MAGMA study uncovered a total of 154 pleiotropic genes capable of influencing multiple brain regions. Lastly, leveraging MR analysis, we concluded that MDD heightens the risk of developing OSA (P=3. 10E-04, OR (95%CI):1.28(1.12~ 1.47)).

Conclusion

In summary, our study identified PCLO as a common gene between OSA and MDD and provided evidence that MDD causally contributes to the development of OSA. These insights enhance our understanding of the shared mechanisms underlying the comorbidity of these conditions.

Acetylome Analyses Provide New Insights into the Effect of Chronic Intermittent Hypoxia on Hypothalamus-Dependent Endocrine Metabolism Impairment

Paediatric obstructive sleep apnoea (OSA) is a highly prevalent sleep disorder resulting in chronic intermittent hypoxia (CIH) that has been linked to metabolism and endocrine impairment. Protein acetylation, which is a frequently occurring posttranslational modification, plays pivotal roles in the regulation of hypothalamic processes. However, the effects of CIH-induced global protein acetylation on hypothalamic function and endocrine metabolism remain poorly understood. To bridge this knowledge gap, we conducted a study utilizing liquid chromatography-mass spectrometry to analyse the lysine acetylome and proteome of the hypothalamus in healthy infantile mice exposed to 3 weeks of intermittent hypoxia (as a CIH model) compared to normoxic mice (as controls). Our analysis identified and quantified 2699 Kac sites in 2453 proteins. These acetylated proteins exhibited disruptions primarily in endocrine metabolism, the citrate cycle (TCA cycle), synapse function, and circadian entrainment. Additionally, we observed significant down-regulation of proteins that are known to be involved in endocrine hormone secretion. This study aimed to elucidate the molecular mechanisms underlying CIH-induced alterations in protein acetylation within the hypothalamus. By providing valuable insights into the pathophysiological processes associated with CIH and their impacts on hypothalamic function, our findings contribute to a deeper understanding of the consequences stemming from CIH-induced changes in protein acetylation within the hypothalamus as well as its potential role in endocrine impairment.

Sleep apnea and ischemic stroke- a perspective for translational preclinical modelling

Obstructive sleep apnea (OSA) is associated with ischemic stroke. There is, however, a lack of knowledge on the exact cause-effect relationship, and preclinical models of OSA for experimental ischemic stroke investigations are not well characterized. In this review, we discuss sleep apnea and its relationship with stroke risk factors. We consider how OSA may lead to ischemic stroke and how OSA-induced metabolic syndrome and hypothalamic-pituitary axis (HPA) dysfunction could serve as therapeutic targets to prevent ischemic stroke. Further, we examine the translational potential of established preclinical models of OSA. We conclude that metabolic syndrome and HPA dysfunction, which are often overlooked in the context of experimental stroke and OSA studies, are crucial for experimental consideration to improve the body of knowledge as well as the translational potential of investigative efforts.

Age-related morphometrics of normal adrenal glands based on deep learning-aided segmentation

OBJECTIVE

This study aims to evaluate the morphometrics of normal adrenal glands in adult patients semiautomatically using a deep learning-based segmentation model.

MATERIALS AND METHODS

A total of 520 abdominal CT image series with normal findings, from January 1, 2016, to March 14, 2019, were retrospectively collected for the training of the adrenal segmentation model. Then, 1043 portal venous phase image series of inpatient contrast-enhanced abdominal CT examinations with normal adrenal glands were included for analysis and grouped by every 10-year gap. A 3D U-Net-based segmentation model was used to predict bilateral adrenal labels followed by manual modification of labels as appropriate. Quantitative parameters (volume, CT value, and diameters) of the bilateral adrenal glands were then analyzed.

RESULTS

In the study cohort aged 18-77 years old (554 males and 489 females), the left adrenal gland was significantly larger than the right adrenal gland [all patients, 2867.79 (2317.11-3499.89) mm³ vs. 2452.84 (1983.50-2935.18) mm³, P < 0.001]. Male patients showed a greater volume of bilateral adrenal glands than females in all age groups (all patients, left: 3237.83 ± 930.21 mm³ vs. 2646.49 ± 766.42 mm³, P < 0.001; right: 2731.69 ± 789.19 mm³ vs. 2266.18 ± 632.97 mm³, P = 0.001). Bilateral adrenal volume in male patients showed an increasing then decreasing trend as age increased that peaked at 38-47 years old (left: 3416.01 ± 886.21 mm³, right: 2855.04 ± 774.57 mm³).

CONCLUSIONS

The semiautomated measurement revealed that the adrenal volume differs as age increases. Male patients aged 38-47 years old have a peaked adrenal volume.

Sleep Problems in Chronic Inflammatory Diseases: Prevalence, Treatment, and New Perspectives: A Narrative Review

Epidemiological studies have shown that individuals with sleep problems are at a greater risk of developing immune and chronic inflammatory diseases. As sleep disorders and low sleep quality in the general population are frequent ailments, it seems important to recognize them as serious public health problems. The exact relation between immunity and sleep remains elusive; however, it might be suspected that it is shaped by others stress and alterations of the circadian rhythm (commonly caused by for example shift work). As studies show, drugs used in the therapy of chronic inflammatory diseases, such as steroids or monoclonal antibodies, also influence sleep in more complex ways than those resulting from attenuation of the disease symptoms. Interestingly, the relation between sleep and immunity appears to be bidirectional; that is, sleep may influence the course of immune diseases, such as inflammatory bowel disease. Thus, proper diagnosis and treatment of sleep disorders are vital to the patient's immune status and, in effect, health. This review examines the epidemiology of sleep disorders and immune diseases, the associations between them, and their current treatment and novel perspectives in therapy.

Gut microbiota modulates stress-induced hypertension through the HPA axis

Stress is associated with an increased risk of hypertension, and the incidence of stress-related hypertension has risen rapidly in recent years; however, the underlying mechanisms remain elusive. Gut dysbiosis has been demonstrated to contribute to hypertension and hyperactivation of the hypothalamus-pituitary-adrenal (HPA) axis. Based on our previous findings showing the altered gut microbiota in the rats of stress-induced hypertension (SIH), the present study aims to investigate whether the stress-induced alteration in gut microbiota can lead to the dysfunction of the HPA axis which contributes to the development of SIH. SIH was developed in rats subjected to electric foot-shock combined with buzzer noise stressors. The gut microbiota of rats were deleted by administering an antibiotic cocktail containing ampicillin (1 g/L), vancomycin (500 mg/L), neomycin (1 g/L), and metronidazole (1 g/L) in drinking water. The serum levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were tested using enzyme-linked immunosorbent assay (ELISA). The mRNA expression of glucocorticoid receptor (GR) and corticotropin-releasing factor (CRF), CRFR1 and CRFR2 was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The cellular protein expressions of corticotropin-releasing hormone (CRH), c-fos, and GR were examined by immunohistochemical staining. In the present study, SIH rats showed a hyperactive HPA axis as indicated by the increased CRH expression in the paraventricular nucleus (PVN) of the hypothalamus, the elevated serum ACTH or CORT concentrations, and increased adrenal gland index. The decreased GR expression and increased CRFR1 in the hypothalamus might underlie the hyperactivation of the HPA axis. The microbial deletion by antibiotics mitigated the hyperactivation of the HPA axis and attenuated the stress-induced elevation of blood pressure, indicating that the causal link of gut microbiota to SIH is mediated, at least in part, by the HPA axis activity. Our findings shed new light on the mechanisms underlying SIH.