Association of Estradiol and Visceral Fat With Structural Brain Networks and Memory Performance in Adults

Metagenomic gut microbiome analysis of Japanese patients with multiple chemical sensitivity/idiopathic environmental intolerance

BACKGROUND

Although the pathology of multiple chemical sensitivity (MCS) is unknown, the central nervous system is reportedly involved. The gut microbiota is important in modifying central nervous system diseases. However, the relationship　between the gut microbiota and MCS remains unclear. This study aimed to identify gut microbiota variations associated with MCS using shotgun metagenomic sequencing of fecal samples.

METHODS

We prospectively recruited 30 consecutive Japanese female patients with MCS and analyzed their gut microbiomes using shotgun metagenomic sequencing. The data were compared with metagenomic data obtained from 24 age- and sex-matched Japanese healthy controls (HC).

RESULTS

We observed no significant difference in alpha and beta diversity of the gut microbiota between the MCS patients and HC. Focusing on the important changes in the literatures, at the genus level, Streptococcus, Veillonella, and Akkermansia were significantly more abundant in MCS patients than in HC (p < 0.01, p < 0.01, p = 0.01, respectively, fold change = 4.03, 1.53, 2.86, respectively). At the species level, Akkermansia muciniphila was significantly more abundant (p = 0.02, fold change = 3.3) and Faecalibacterium prausnitzii significantly less abundant in MCS patients than in HC (p = 0.03, fold change = 0.53). Functional analysis revealed that xylene and dioxin degradation pathways were significantly enriched (p < 0.01, p = 0.01, respectively, fold change = 1.54, 1.46, respectively), whereas pathways involved in amino acid metabolism and synthesis were significantly depleted in MCS (p < 0.01, fold change = 0.96). Pathways related to antimicrobial resistance, including the two-component system and cationic antimicrobial peptide resistance, were also significantly enriched in MCS (p < 0.01, p < 0.01, respectively, fold change = 1.1, 1.2, respectively).

CONCLUSIONS

The gut microbiota of patients with MCS shows dysbiosis and alterations in bacterial functions related to exogenous chemicals and amino acid metabolism and synthesis. These findings may contribute to the further development of treatment for MCS.

TRIAL REGISTRATION

This study was registered with the University Hospital Medical Information Clinical Trials Registry as UMIN000031031. The date of first trial registration: 28/01/2018.

Plasma homocysteine level, estradiol level, and brain atrophy: a Mendelian randomization study

OBJECTIVES

Observational studies link elevated plasma homocysteine (Hcy) with vascular disease. Our aim was to assess the gender difference in the association between the plasma tHcy level and brain atrophy and identify the possible influencer. We employed Mendelian randomization (MR) to explore the causal relationship between plasma tHcy level, estradiol level, and brain atrophy.

METHODS

A total of 687 patients with brain atrophy were included, and gender-specific subgroup analyses in association between tHcy and brain atrophy are conducted. From genome-wide association studies, we selected genetic variants (P < 5 × 10-8) for the plasma tHcy level and estradiol level. We investigated the degree of brain atrophy (including gray matter volume and total brain volume) in the UK biobank (n = 7,916). The inverse variance-weighted and several sensitivity MR regression analyses were carried out.

RESULTS

The plasma tHcy level was significantly associated with brain atrophy for females, but not for males. An MR study showed that there was little evidence of the causal link between elevated plasma tHcy and brain atrophy. On the other hand, we found evidence to support causality for genetically decreased estradiol with higher risk of brain atrophy. Furthermore, genetic predisposition to elevated plasma tHcy was associated with a lower estradiol level.

CONCLUSIONS

The influence of estradiol on the association between tHcy and brain atrophy deserves further investigation.

The role of cognitive function in the relationship between surrogate markers of visceral fat and depressive symptoms in general middle-aged and elderly population: A nationwide population-based study

BACKGROUND

The relationship between obesity and depressive symptoms is well documented, but not visceral fat, especially among Chinese adults are scarce. We aimed to investigate the association between visceral fat and depressive symptoms and the mediation of cognitive function.

METHODS

A total of 19,919 and 5555 participants from the China Health and Retirement Longitudinal Study were enrolled in the cross-sectional and follow-up analyses. Depressive symptoms were measured by the Center of Epidemiological studies depression scale (CES-D). Visceral fat measured by the waist circumference triglyceride (WT) index [calculated as waist circumference (cm)* triglyceride (mmol/L)]. The relationship between the WT index and depressive symptoms was analyzed by binary logistics and Poisson regression. The mediated role of cognitive ability was examined by intermediary analysis.

RESULTS

In the cross-sectional study, higher visceral fat was associated with a lower risk of depressive symptoms. But in the follow-up study, individuals in quintile 2 to quintile 4 of the WT index have a reduced risk of depressive symptoms after four years. Compared with the lower index, quintile 2 of the WT index protected from difficulty concentrating (RR [95%CI]: 0.90 [0.82,0.98], p = 0.023), feeling scared (RR [95%CI]: 0.86 [0.73,0.98], p = 0.030) and feeling that life could not go on (RR [95%CI]: 0.85 [0.74,0.98], p = 0.023). Moreover, cognitive ability explained 11.52 % of the association between visceral fat and depressive symptoms.

CONCLUSIONS

Our findings show that moderate visceral fat was associated with a lower risk of depressive symptoms in middle-aged and older Chinese, partly mediated by cognitive function.

Relationships Between Body Composition and Cognitive Impairment in Hospitalised Middle-Aged Type 2 Diabetic Patients

Objective

The aim of this study was to elucidate the relationship between specific body composition and the risk of Cognitive Impairment (CI) in middle-aged Type 2 Diabetes Mellitus (T2DM) patients.

Methods

This cross-sectional study included 504 hospitalized patients with T2DM from the Department of Endocrinology and Metabolism of the Tianjin Union Medical Center. Subjects were grouped by sex, and cognitive status was assessed using the Montreal Cognitive Assessment (MoCA). The relationship between body composition and cognitive ability was investigated with the use of linear regression analysis. The association between body composition and CI risk was determined by logistic regression analysis.

Results

The prevalence of CI was 39.3% in middle-aged T2DM patients. After adjusting for age, education, marriage status, carotid atherosclerosis, cerebrovascular disease and hemoglobin, multiple linear regression analysis showed that lean mass index (LMI), body mass index (BMI) and appendicular skeletal muscle index (SMI) were significant predictors for the MoCA scores in men (p < 0.05). In addition, BMI (OR 0.913, 95% CI 0.840-0.992) and LMI (OR 0.820, 95% CI 0.682-0.916) were independent protective factors for CI in males. After adjusted for age, education, marriage status, dietary control of diabetes and cerebrovascular disease, visceral obesity (VO, OR 1.950, 95% CI 1.033-3.684) and abdominal obesity (AO, OR 2.537, 95% CI 1.191-5.403) were risk factors for CI in female patients.

Conclusion

The results suggest that there may be different mechanisms underlying the relationship of body compositions and cognitive performance between middle-aged male and female patients with T2DM. In addition, our finding of potential determinants of cognitive impairment may facilitate the development of intervention programs for middle-aged type 2 diabetic patients. Nevertheless, more large prospective studies looking at cognition and changes in body composition over time are needed in the future to further support their association.

The association between regional adiposity, cognitive function, and dementia-related brain changes: a systematic review

Background

Adiposity has been previously associated with cognitive impairment and Alzheimer's disease and related disorders (ADRD). Body mass index (BMI) is the most common measure of global adiposity, but inconsistent results were found since it is a global measurement. BMI does not represent regional fat distribution which differs between sexes, race, and age. Regional fat distribution may contribute differently to cognitive decline and Alzheimer's disease (AD)-related brain changes. Fat-specific targeted therapies could lead to personalized improvement of cognition. The goal of this systematic review is to explore whether regional fat depots, rather than central obesity, should be used to understand the mechanism underlying the association between adiposity and brain.

Methods

This systematic review included 33 studies in the English language, conducted in humans aged 18 years and over with assessment of regional adiposity, cognitive function, dementia, and brain measures. We included only studies that have assessed regional adiposity using imaging technics and excluded studies that were review articles, abstract only or letters to editor. Studies on children and adolescents, animal studies, and studies of patients with gastrointestinal diseases were excluded. PubMed, PsychInfo and web of science were used as electronic databases for literature search until November 2022.

Results

Based on the currently available literature, the findings suggest that different regional fat depots are likely associated with increased risk of cognitive impairment, brain changes and dementia, especially AD. However, different regional fat depots can have different cognitive outcomes and affect the brain differently. Visceral adipose tissue (VAT) was the most studied regional fat, along with liver fat through non-alcoholic fatty liver disease (NAFLD). Pancreatic fat was the least studied regional fat.

Conclusion

Regional adiposity, which is modifiable, may explain discrepancies in associations of global adiposity, brain, and cognition. Specific regional fat depots lead to abnormal secretion of adipose factors which in turn may penetrate the blood brain barrier leading to brain damage and to cognitive decline.

Neuroimaging Investigations of Obesity: a Review of the Treatment of Sex from 2010

PURPOSE OF REVIEW

To summarize the results of adult obesity neuroimaging studies (structural, resting-state, task-based, diffusion tensor imaging) published from 2010, with a focus on the treatment of sex as an important biological variable in the analysis, and identify gaps in sex difference research.

RECENT FINDINGS

Neuroimaging studies have shown obesity-related changes in brain structure, function, and connectivity. However, relevant factors such as sex are often not considered. We conducted a systematic review and keyword co-occurrence analysis. Literature searches identified 6281 articles, of which 199 met inclusion criteria. Among these, only 26 (13%) considered sex as an important variable in the analysis, directly comparing the sexes (n = 10; 5%) or providing single-sex/disaggregated data (n = 16, 8%); the remaining studies controlled for sex (n = 120, 60%) or did not consider sex in the analysis (n = 53, 27%). Synthesizing sex-based results, obesity-related parameters (e.g., body mass index, waist circumference, obese status) may be generally associated with more robust morphological alterations in men and more robust structural connectivity alterations in women. Additionally, women with obesity generally expressed increased reactivity in affect-related regions, while men with obesity generally expressed increased reactivity in motor-related regions; this was especially true under a fed state. The keyword co-occurrence analysis indicated that sex difference research was especially lacking in intervention studies. Thus, although sex differences in the brain associated with obesity are known to exist, a large proportion of the literature informing the research and treatment strategies of today has not specifically examined sex effects, which is needed to optimize treatment.

Effects of follicle-stimulating hormone on fat metabolism and cognitive impairment in women during menopause

Lipid metabolism disorder is a common pathological manifestation of menopausal women, and is also an important risk factor for many diseases at this stage of life. Epidemiological studies have shown that high levels of follicle-stimulating hormone (FSH) in menopausal women are closely associated with changes in body composition, central obesity, and cognitive decline. Exogenous FSH causes growth and proliferation of adipose, whereas blockage of the FSH signaling pathway leads to decline in adipose. Mechanistically, FSH, FSH receptor (FSHR), G protein coupling, gene mutation and other pathways are involved in adipogenesis and cognitive impairment. Here, we review the critical role and potential interactions of FSH in adipogenesis and cognitive impairment in menopausal women. Further understanding of the exact mechanisms of FSH aggravating obesity and cognitive impairment may provide a new perspective for promoting healthy aging in menopausal women.

Impact of obesity and diet on brain structure and function: a gut-brain-body crosstalk

Most societies witness an ever increasing prevalence of both obesity and dementia, a scenario related to often underestimated individual and public health burden. Overnutrition and weight gain have been linked with abnormal functionality of homoeostasis brain networks and changes in higher cognitive functions such as reward evaluation, executive functions and learning and memory. In parallel, evidence has accumulated that modifiable factors such as obesity and diet impact the gut-brain axis and modulate brain health and cognition through various pathways. Using neuroimaging data from epidemiological studies and randomised clinical trials, we aim to shed light on the underlying mechanisms and to determine both determinants and consequences of obesity and diet at the level of human brain structure and function. We analysed multimodal 3T MRI of about 2600 randomly selected adults (47 % female, 18-80 years of age, BMI 18-47 kg/m²) of the LIFE-Adult study, a deeply phenotyped population-based cohort. In addition, brain MRI data of controlled intervention studies on weight loss and healthy diets acquired in lean, overweight and obese participants may help to understand the role of the gut-brain axis in food craving and cognitive ageing. We find that higher BMI and visceral fat accumulation correlate with accelerated brain age, microstructure of the hypothalamus, lower thickness and connectivity in default mode- and reward-related areas, as well as with subtle grey matter atrophy and white matter lesion load in non-demented individuals. Mediation analyses indicated that higher visceral fat affects brain tissue through systemic low-grade inflammation, and that obesity-related regional changes translate into cognitive disadvantages. Considering longitudinal studies, some, but not all data indicate beneficial effects of weight loss and healthy diets such as plant-based nutrients and dietary patterns on brain ageing and cognition. Confounding effects of concurrent changes in other lifestyle factors or false positives might help to explain these findings. Therefore a more holistic intervention approach, along with open science tools such as data and code sharing, in-depth pre-registration and pooling of data could help to overcome these limitations. In addition, as higher BMI relates to increased head micro-movements during MRI, and as head motion in turn systematically induces image artefacts, future studies need to rigorously control for head motion during MRI to enable valid neuroimaging results. In sum, our results support the view that overweight and obesity are intertwined with markers of brain health in the general population, and that weight loss and plant-based diets may help to promote brain plasticity. Meta-analyses and longitudinal cohort studies are underway to further differentiate causation from correlation in obesity- and nutrition-brain research.

Effects of reducing sedentary behaviour duration by increasing physical activity, on cognitive function, brain function and structure across the lifespan: a systematic review protocol

INTRODUCTION

Greater engagement in sedentary behaviours has been related to poorer cognitive functions in epidemiological research. However, the effects of reducing sedentary behaviour duration on cognitive function, brain function, and structure remain poorly understood. This systematic review aims to synthesise the evidence on the effects of reducing sedentary behaviour duration by increasing time spent in physical activity on cognitive function, brain structure and function in apparently healthy children, adolescents and adults.

METHODS AND ANALYSIS

The protocol follows Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The literature search will be conducted (search dates: August-September 2022) across six databases: PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (via EBSCO Host), PsycINFO (via ProQuest), SPORTDiscus and Web of Science (Science and Social Science Citation Index). The inclusion criteria are as follows: randomised and non-randomised experimental studies as defined by the Cochrane Handbook, published in English, in peer-reviewed journals, and as theses or dissertations. References of included papers will be screened for additional studies. Acute and chronic interventions targeting children (≥ 4 years), adolescents, younger adults (≥ 18-40 years), middle-aged (40-64 years) and older adults (65+ years) will be eligible. Methodological quality will be assessed with the Effective Public Health Practice Project quality assessment tool for quantitative studies. Qualitative synthesis will be stratified by intervention type (acute vs chronic), intervention content (reducing sedentary time or interrupting prolonged sitting) and outcome (cognitive, brain structure and function).

ETHICS AND DISSEMINATION

No primary data collection will be conducted as part of this systematic review. Study findings will be disseminated through peer-reviewed publications, conference presentations and social media.

PROSPERO REGISTRATION NUMBER

CRD42020200998.

Bidirectional communication between brain and visceral white adipose tissue: Its potential impact on Alzheimer's disease

A variety of axes between brain and abdominal organs have been reported, but the interaction between brain and visceral white adipose tissue (vWAT) remains unclear. In this review, we summarized human studies on the association between brain and vWAT, and generalized their interaction and the underlying mechanisms according to animal and cell experiments. On that basis, we come up with the concept of the brain-vWAT axis (BVA). Furthermore, we analyzed the potential mechanisms of involvement of BVA in the pathogenesis of Alzheimer's disease (AD), including vWAT-derived fatty acids, immunological properties of vWAT, vWAT-derived retinoic acid and vWAT-regulated insulin resistance. The proposal of BVA may expand our understanding to some extent of how the vWAT impacts on brain health and diseases, and provide a novel approach to study the pathogenesis and treatment strategies of neurodegenerative disorders.

Management of menopause: a view towards prevention

Women spend approximately one-third of their lives with menopause, which occurs around 50 years of age. It is now appreciated that several important metabolic and cardiovascular disease risks emerge during the menopausal transition. Many important conditions occur 10-15 years after menopause, including weight gain and obesity, metabolic syndrome, diabetes, osteoporosis, arthritis, cardiovascular disease, dementia, and cancer; therefore, the occurrence of menopause heralds an important opportunity to institute preventative strategies. These strategies will lead to improved quality of life and decreased mortality. Various strategies are presented for treating symptoms of menopause and diseases that are asymptomatic. Among several strategies is the use of hormone therapy, which has efficacy for symptoms and osteoporosis, and can improve metabolic and cardiovascular health. When instituted early, which is key, in younger postmenopausal women (under 60 years) oestrogen has been found to consistently decrease mortality with a favourable risk-benefit profile in low-risk women. Prospective data show that long-term therapy might not be required for this benefit.

Sex Differences in Cognition Across Aging

Sex and gender differences are seen in cognitive disturbances in a variety of neurological and psychiatry diseases. Men are more likely to have cognitive symptoms in schizophrenia whereas women are more likely to have more severe cognitive symptoms with major depressive disorder and Alzheimer's disease. Thus, it is important to understand sex and gender differences in underlying cognitive abilities with and without disease. Sex differences are noted in performance across various cognitive domains - with males typically outperforming females in spatial tasks and females typically outperforming males in verbal tasks. Furthermore, there are striking sex differences in brain networks that are activated during cognitive tasks and in learning strategies. Although rarely studied, there are also sex differences in the trajectory of cognitive aging. It is important to pay attention to these sex differences as they inform researchers of potential differences in resilience to age-related cognitive decline and underlying mechanisms for both healthy and pathological cognitive aging, depending on sex. We review literature on the progressive neurodegenerative disorder, Alzheimer's disease, as an example of pathological cognitive aging in which human females show greater lifetime risk, neuropathology, and cognitive impairment, compared to human males. Not surprisingly, the relationships between sex and cognition, cognitive aging, and Alzheimer's disease are nuanced and multifaceted. As such, this chapter will end with a discussion of lifestyle factors, like education and diet, as modifiable factors that can alter cognitive aging by sex. Understanding how cognition changes across age and contributing factors, like sex differences, will be essential to improving care for older adults.

The Potential Crosstalk Between the Brain and Visceral Adipose Tissue in Alzheimer's Development

The bidirectional communication between the brain and peripheral organs have been widely documented, but the impact of visceral adipose tissue (VAT) dysfunction and its relation to structural and functional brain changes have yet to be fully elucidated. This review initially examines the clinical evidence supporting associations between the brain and VAT before visiting the roles of the autonomic nervous system, fat and glucose metabolism, neuroinflammation, and metabolites. Finally, the possible effects and potential mechanisms of the brain-VAT axis on the pathogenesis of Alzheimer's disease are discussed, providing new insights regarding future prevention and therapeutic strategies.

Associations between abdominal adipose tissue, reproductive span, and brain characteristics in post-menopausal women

The menopause transition involves changes in oestrogens and adipose tissue distribution, which may influence female brain health post-menopause. Although increased central fat accumulation is linked to risk of cardiometabolic diseases, adipose tissue also serves as the primary biosynthesis site of oestrogens post-menopause. It is unclear whether different types of adipose tissue play diverging roles in female brain health post-menopause, and whether this depends on lifetime oestrogen exposure, which can have lasting effects on the brain and body even after menopause. Using the UK Biobank sample, we investigated associations between brain characteristics and visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (ASAT) in 10,251 post-menopausal females, and assessed whether the relationships varied depending on length of reproductive span (age at menarche to age at menopause). To parse the effects of common genetic variation, we computed polygenic scores for reproductive span. The results showed that higher VAT and ASAT were both associated with higher grey and white matter brain age, and greater white matter hyperintensity load. The associations varied positively with reproductive span, indicating more prominent associations between adipose tissue and brain measures in females with a longer reproductive span. The effects were in general small, but could not be fully explained by genetic variation or relevant confounders. Our findings indicate that associations between abdominal adipose tissue and brain health post-menopause may partly depend on individual differences in cumulative oestrogen exposure during reproductive years, emphasising the complexity of neural and endocrine ageing processes in females.

Violent suicide attempt history in elderly patients with bipolar disorder: The role of sex, abdominal obesity, and verbal memory: Results from the FACE-BD cohort (FondaMental Advanced center of Expertise for Bipolar Disorders)

BACKGROUND

Bipolar disorder (BD) is a chronic, lifelong condition, associated with increased risk of obesity, cognitive impairment, and suicidal behaviors. Abdominal obesity and a higher risk of violent suicide attempt (SA) seem to be shared correlates with older age, BD, and male sex until middle age when menopause-related female body changes occur. This study aimed at assessing the role of abdominal obesity and cognition in the violent SA burden of individuals with BD.

METHODS

From the well-defined nationwide cohort FACE-BD (FondaMental Advanced center of Expertise for Bipolar Disorders), we extracted data on 619 euthymic BD patients that were 50 years or older at inclusion. Cross-sectional clinical, cognitive, and metabolic assessments were performed. SA history was based on self-report.

RESULTS

Violent SA, in contrast to non-violent and no SA, was associated with higher waist circumference, abdominal obesity and poorer California Verbal Learning Test short-delay free recall (CVLT-SDFR) (ANOVA, p < .001, p = .014, and p = .006). Waist circumference and abdominal obesity were associated with violent SA history independently of sex, BD type and anxiety disorder (Exp(B) 1.02, CI 1.00-1.05, p = .018; Exp(B) 2.16, CI 1.00-4.64, p = .009, accordingly). In an exploratory model, waist circumference and CVLT-SDFR performance mediated the association between male sex and violent SA.

LIMITATIONS

Cross-sectional design and retrospective reporting.

CONCLUSIONS

Violent SA history was associated with abdominal obesity and poorer verbal memory in older age BD patients. These factors were interlinked and might mediate the association between male sex and violent SA.

In search of sex-related mediators of affective illness

Sex differences in the rates of affective disorders have been recognized for decades. Studies of physiologic sex-related differences in animals and humans, however, have generally yielded little in terms of explaining these differences. Furthermore, the significance of these findings is difficult to interpret given the dynamic, integrative, and highly context-dependent nature of human physiology. In this article, we provide an overview of the current literature on sex differences as they relate to mood disorders, organizing existing findings into five levels at which sex differences conceivably influence physiology relevant to affective states. These levels include the following: brain structure, network connectivity, signal transduction, transcription/translation, and epigenesis. We then evaluate the importance and limitations of this body of work, as well as offer perspectives on the future of research into sex differences. In creating this overview, we attempt to bring perspective to a body of research that is complex, poorly synthesized, and far from complete, as well as provide a theoretical framework for thinking about the role that sex differences ultimately play in affective regulation. Despite the overall gaps regarding both the underlying pathogenesis of affective illness and the role of sex-related factors in the development of affective disorders, it is evident that sex should be considered as an important contributor to alterations in neural function giving rise to susceptibility to and expression of depression.

Drug Repurposing for Alzheimer's Disease Based on Protein-Protein Interaction Network

Alzheimer's disease (AD) is known as a critical neurodegenerative disorder. It worsens as symptoms concerning dementia grow severe over the years. Due to the globalization of Alzheimer's disease, its prevention and treatment are vital. This study proposes a method to extract substantial gene complexes and then introduces potential drugs in Alzheimer's disease. To this end, a protein-protein interaction (PPI) network was utilized to extract five meaningful gene complexes functionally interconnected. An enrichment analysis to introduce the most important biological processes and pathways was accomplished on the obtained genes. The next step is extracting the drugs related to AD and introducing some new drugs which may be helpful for this disease. Finally, a complete network including all the genes associated with each gene complex group and genes' target drug was illustrated. For validating the proposed potential drugs, Connectivity Map (CMAP) analysis was accomplished to determine target genes that are up- or downregulated by proposed drugs. Medical studies and publications were analyzed thoroughly to introduce AD-related drugs. This analysis proves the accuracy of the proposed method in this study. Then, new drugs were introduced that can be experimentally examined as future work. Raloxifene and gentian violet are two new drugs, which have not been introduced as AD-related drugs in previous scientific and medical studies, recommended by the method of this study. Besides the primary goal, five bipartite networks representing the genes of each group and their target miRNAs were constructed to introduce target miRNAs.

Drug repositioning based on network-specific core genes identifies potential drugs for the treatment of autism spectrum disorder in children

Identification of exact causative genes is important for in silico drug repositioning based on drug-gene-disease relationships. However, the complex polygenic etiology of the autism spectrum disorder (ASD) is a challenge in the identification of etiological genes. The network-based core gene identification method can effectively use the interactions between genes and accurately identify the pathogenic genes of ASD. We developed a novel network-based drug repositioning framework that contains three steps: network-specific core gene (NCG) identification, potential therapeutic drug repositioning, and candidate drug validation. First, through the analysis of transcriptome data for 178 brain tissues, gene network analysis identified 365 NCGs in 18 coexpression modules that were significantly correlated with ASD. Second, we evaluated two proposed drug repositioning methods. In one novel approach (dtGSEA), we used the NCGs to probe drug-gene interaction data and identified 35 candidate drugs. In another approach, we compared NCG expression patterns with drug-induced transcriptome data from the Connectivity Map database and found 46 candidate drugs. Third, we validated the candidate drugs using an in-house mental diseases and compounds knowledge graph (MCKG) that contained 7509 compounds, 505 mental diseases, and 123,890 edges. We found a total of 42 candidate drugs that were associated with mental illness, among which 10 drugs (baclofen, sulpiride, estradiol, entinostat, everolimus, fluvoxamine, curcumin, calcitriol, metronidazole, and zinc) were postulated to be associated with ASD. This study proposes a powerful network-based drug repositioning framework and also provides candidate drugs as well as potential drug targets for the subsequent development of ASD therapeutic drugs.

Association Between Visceral Fat and Brain Cortical Thickness in the Elderly: A Neuroimaging Study

Background

Despite emerging evidence suggesting that visceral fat may play a major role in obesity-induced neurodegeneration, little evidence exists on the association between visceral fat and brain cortical thickness in the elderly.

Purpose

We aimed to examine the association between abdominal fat and brain cortical thickness in a Korean elderly population.

Methods

This cross-sectional study included elderly individuals without dementia (n = 316). Areas of visceral fat and subcutaneous fat (cm²) were estimated from computed tomography scans. Regional cortical thicknesses (mm) were obtained by analyzing brain magnetic resonance images. Given the inverted U-shaped relationship between visceral fat area and global cortical thickness (examined using a generalized additive model), visceral fat area was categorized into quintiles, with the middle quintile being the reference group. A generalized linear model was built to explore brain regions associated with visceral fat. The same approach was used for subcutaneous fat.

Results

The mean (standard deviation) age was 67.6 (5.0) years. The highest quintile (vs. the middle quintile) group of visceral fat area had reduced cortical thicknesses in the global [β = -0.04 mm, standard error (SE) = 0.02 mm, p = 0.004], parietal (β = -0.04 mm, SE = 0.02 mm, p = 0.01), temporal (β = -0.05 mm, SE = 0.02 mm, p = 0.002), cingulate (β = -0.06 mm, SE = 0.02 mm, p = 0.01), and insula lobes (β = -0.06 mm, SE = 0.03 mm, p = 0.02). None of the regional cortical thicknesses significantly differed between the highest and the middle quintile groups of subcutaneous fat area.

Conclusion

The findings suggest that a high level of visceral fat, but not subcutaneous fat, is associated with a reduced cortical thickness in the elderly.

The development of structural covariance networks during the transition from childhood to adolescence

Structural covariance conceptualizes how morphologic properties of brain regions are related to one another (across individuals). It can provide unique information to cortical structure (e.g., thickness) about the development of functionally meaningful networks. The current study investigated how structural covariance networks develop during the transition from childhood to adolescence, a period characterized by marked structural re-organization. Participants (N = 192; scans = 366) completed MRI assessments between 8.5 and 14.5 years of age. A sliding window approach was used to create “age-bins”, and structural covariance networks (based on cortical thickness) were created for each bin. Next, generalized additive models were used to characterize trajectories of age-related changes in network properties. Results revealed nonlinear trajectories with “peaks” in mean correlation and global density that are suggestive of a period of convergence in anatomical properties across the cortex during early adolescence, prior to regional specialization. “Hub” regions in sensorimotor cortices were present by late childhood, but the extent and strength of association cortices as “hubs” increased into mid-adolescence. Moreover, these regional changes were found to be related to rates of thinning across the cortex. In the context of neurocognitive networks, the frontoparietal, default mode, and attention systems exhibited age-related increases in within-network and between-network covariance. These regional and modular developmental patterns are consistent with continued refinement of socioemotional and other complex executive functions that are supported by higher-order cognitive networks during early adolescence.

Estrogen, brain structure, and cognition in postmenopausal women

Declining estrogen levels before, during, and after menopause can affect memory and risk for Alzheimer's disease. Undesirable side effects of hormone variations emphasize a role for hormone therapy (HT) where possible benefits include a delay in the onset of dementia-yet findings are inconsistent. Effects of HT may be mediated by estrogen receptors found throughout the brain. Effects may also depend on lifestyle factors, timing of use, and genetic risk. We studied the impact of self-reported HT use on brain volume in 562 elderly women (71-94 years) with mixed cognitive status while adjusting for aforementioned factors. Covariate-adjusted voxelwise linear regression analyses using a model with 16 predictors showed HT use as positively associated with regional brain volumes, regardless of cognitive status. Examinations of other factors related to menopause, oophorectomy and hysterectomy status independently yielded positive effects on brain volume when added to our model. One interaction term, HTxBMI, out of several examined, revealed significant negative association with overall brain volume, suggesting a greater reduction in brain volume than BMI alone. Our main findings relating HT to regional brain volume were as hypothesized, but some exploratory analyses were not in line with existing hypotheses. Studies suggest lower levels of estrogen resulting from oophorectomy and hysterectomy affect brain volume negatively, and the addition of HT modifies the relation between BMI and brain volume positively. Effects of HT may depend on the age range assessed, motivating studies with a wider age range as well as a randomized design.

Adiposity-related insulin resistance and thickness of the cerebral cortex in middle-aged adults

The thickness of the cerebral cortex decreases with ageing. Recent research suggests that obesity and type 2 diabetes mellitus may accelerate this cortical thinning, and that obesity-related insulin resistance may be a shared mechanistic pathway. Ageing of the cerebral cortex demonstrates sex-specific trajectories, with a gradual shift towards accelerated thinning beginning in midlife. Here, we investigated whether adiposity-related insulin resistance is associated with lower thickness of the human cerebral cortex in a community-based sample of middle-aged adults. We studied 533 adult participants (36-65 years) from the Saguenay Youth Study. Adiposity was assessed with bioimpedance, and insulin resistance was evaluated from a fasting blood sample with the homeostatic model assessment of insulin resistance (HOMA-IR). Associations between adiposity-related insulin resistance (adiposity/IR) and cortical thickness were assessed with linear models, separately in males and females younger or older than 50 years. Potential biological underpinnings were investigated with virtual histology. Adiposity/IR was associated with lower cortical thickness in females older than 50 years but not in males or younger females. The strength of the association varied across the cerebral cortex, with regions of the lateral frontal and parietal cortices and the superior temporal cortex demonstrating most pronounced thinning. Based on virtual histology, adiposity/IR-related cortical thinning may involve neurones, astrocytes, oligodendrocytes and ependymal cells acting so that they lower the cortical potential for synaptogenesis, formation of dendritic spines, production of extracellular matrix and myelination. Adiposity-related insulin resistance is associated with lower cortical thickness in middle-aged women older than 50 years. This aspect of thinning may involve neuronal and glial cells in a way that lowers the capacity of the cerebral cortex for neuronal plasticity and maintenance of myelination.

Association Between 17-β-Estradiol and Interleukin-8 and Visual Field Progression in Postmenopausal Women with Primary Angle Closure Glaucoma

PURPOSE

To investigate an association between sex hormones and inflammatory cytokines, and to determine whether baseline 17-β-estradiol (E2) and interleukin-8 (IL-8) are associated with visual field (VF) progression in postmenopausal women with primary angle closure glaucoma (PACG).

DESIGN

A prospective cross-sectional and cohort study.

PARTICIPANTS

The cross-sectional study enrolled 200 postmenopausal women with PACG and 151 healthy postmenopausal women as normal control subjects. A total of 105 postmenopausal women with PACG were included and followed up for ≥2 years in the cohort study.

METHODS

All participants were evaluated for levels of baseline sex hormones (follicle-stimulating hormone, prolactin, progesterone, testosterone, luteinizing hormone, and E2) and inflammatory cytokines (IL-1, IL-2, IL-6, IL-8, IL-10, and C-reactive protein) and underwent VF examinations. The cross-sectional study was conducted to establish risk factors for postmenopausal women with PACG using logistic regression analysis. The cohort study was designed to identify factors that could be used to predict VF progression in postmenopausal women with PACG using multivariate Cox regression analyses. The main outcome measures included factors associated with VF progression over time.

RESULTS

Decreased E2 (odds ratio 0.88 [95% confidence interval {CI} 0.78-0.99], P = .007) and increased IL-8 (odds ratio 1.12 [95% CI 1.01-1.23], P < .001) levels were risk factors in postmenopausal women with PACG. A significant negative correlation was observed between IL-8 levels and E2 (r = -0.21, P = .02). Multivariable regression analyses revealed a significant correlation between E2 levels and visual field mean deviation (MD) (B = -0.16, P = .04 [95% CI -.09 to -.003) and between IL-8 levels and MD (B = 0.36, P < .001 [95% CI 0.01-0.02]). During follow-up, 48 (45.71%) patients showed VF progression. Lower baseline E2 (hazard ratio 0.85 [95% CI 0.82-0.88], P = .04) and higher baseline IL-8 levels (hazard ratio 1.01 [95% CI 1.00-1.02], P = .004) were associated with progression of glaucoma. Patients with lower E2 levels had a significantly higher rate of PACG progression (log-rank test P < .001), similar to those with higher IL-8 levels (log-rank test P = .04).

CONCLUSIONS

Decreased E2 and increased IL-8 levels at baseline are significant predictors of VF progression in postmenopausal women with PACG.

Inadequacy of Vitamin D Nutritional Status in Individuals with Metabolically Unhealthy Obesity Phenotype: The Relevance of Insulin Resistance

PURPOSE

The aim was to evaluate 25(OH)D serum concentrations in metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUHO) and its relation with biochemical and clinical parameters in both groups according to homeostatic model assessment-insulin resistance (HOMA-IR) definition of the obesity phenotypes.

PATIENTS AND METHODS

Descriptive cross-sectional study was conducted with individuals of both genders. Anthropometric data [waist circumference, body mass index (BMI)] and metabolic parameters: blood glucose, glycated hemoglobin, insulin, lipid profile, calcium, phosphorus, parathyroid hormone (PTH) and high-sensitivity c-reactive protein (hs-CRP) and (25(OH)D) were obtained. The cutoff points for vitamin D deficiency and insufficiency were ≤20 and 21-29 ng/mL, respectively. Individuals were classified as MUHO according to HOMA-IR≥2.5.

RESULTS

This study comprised 232 individuals with obesity (BMI≥35 kg/m²; 42.6±4.7 kg/m²). The MUHO phenotype was observed in 76.7% of the population. The mean values of glucose (P<0.001), insulin (P<0.001), HOMA-IR (P<0.001), and triglycerides (P=0.049) were significantly higher in the MUHO than in the MHO phenotype group. The mean value of 25(OH)D showed a significant difference between the MHO and MUHO phenotype groups (P=0.011). Additionally, and in line, lower mean 25(OH)D values were found in the MUHO vs the MHO phenotype group in the deficiency (14.5±3.6 ng/mL/17.1±2.7 ng/mL, P=0.004) and insufficiency (24.5±2.9 ng/mL/25.7±2.6 ng/mL, P=0.077) 25(OH)D groups. An increase of 1 ng/mL of vitamin D increased in 1.051 (95% CI= 1.011-1.093, P=0.012) the odds of the healthy phenotype.

CONCLUSION

The highest prevalence of inadequacy of serum concentrations of 25(OH)D and greater severity of this deficiency in individuals with MUHO phenotype were observed. Low serum concentrations of this vitamin were associated, mainly, with insulin resistance. Monitoring the nutritional status of vitamin D in individuals with obesity that present with MUHO phenotype may contribute to minimize the occurrence and aggravation of diseases associated with obesity.