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Hypothalamic volume, sleep, and APOE genotype in cognitively healthy adults
INTRODUCTION: Sleep dysfunction in those at higher risk of dementia may be associated with early structural changes to the hypothalamus. METHODS: We used multivariate regression to analyze self-reported sleep (Pittsburgh Sleep Quality Index [PSQI]) from cognitively healthy participants in the PREVENT Dementia and Alzheimer's and Families (ALFA) studies (n = 1939), stratified by apolipoprotein E (APOE) genotype as homozygotes, heterozygotes, and non-carriers. FreeSurfer was used to extract hypothalamic subunit volumes from T1-weighted magnetic resonance images. RESULTS: APOE ε4 homozygotes had a larger anterior–superior hypothalamus compared to heterozygotes and non-carriers, an effect which was driven by younger people in the cohort. APOE ε4 carriers had a higher PSQI global score after age 55, and smaller anterior–superior and tubular–superior subunits were associated with more sleep disturbances. Sleep duration and efficiency worsened with age, but only in participants with a small anterior–inferior hypothalamus. DISCUSSION: This suggests that aging and APOE ε4 are associated with hypothalamic changes, highlighting mechanisms linking sleep dysfunction to dementia. Highlights: Apolipoprotein E (APOE) ε4 homozygotes ha a larger anterior–superior hypothalamus. APOE ε4 carriers have worse sleep, but only after age 55. Worse sleep in APOE ε4 carriers was associated with smaller hypothalamic subunits. Higher age was associated with worse sleep in people with a small hypothalamus.
Pain in women: bridging the gender pain gap.
Bridging the gender pain gap requires collaborative efforts that address female-specific biological and psychosocial dimensions of pain through evidence-based, compassionate and empathy-driven approaches.
Effect of climate on traits of dominant and rare tree species in the world's forests.
Species' traits and environmental conditions determine the abundance of tree species across the globe. The extent to which traits of dominant and rare tree species differ remains untested across a broad environmental range, limiting our understanding of how species traits and the environment shape forest functional composition. We use a global dataset of tree composition of >22,000 forest plots and 11 traits of 1663 tree species to ask how locally dominant and rare species differ in their trait values, and how these differences are driven by climatic gradients in temperature and water availability in forest biomes across the globe. We find three consistent trait differences between locally dominant and rare species across all biomes; dominant species are taller, have softer wood and higher loading on the multivariate stem strategy axis (related to narrow tracheids and thick bark). The difference between traits of dominant and rare species is more strongly driven by temperature compared to water availability, as temperature might affect a larger number of traits. Therefore, climate change driven global temperature rise may have a strong effect on trait differences between dominant and rare tree species and may lead to changes in species abundances and therefore strong community reassembly.
Global, Regional, and National Burden of Nontraumatic Subarachnoid Hemorrhage: The Global Burden of Disease Study 2021.
IMPORTANCE: Nontraumatic subarachnoid hemorrhage (SAH) represents the third most common stroke type with unique etiologies, risk factors, diagnostics, and treatments. Nevertheless, epidemiological studies often cluster SAH with other stroke types leaving its distinct burden estimates obscure. OBJECTIVE: To estimate the worldwide burden of SAH. DESIGN, SETTING, AND PARTICIPANTS: Based on the repeated cross-sectional Global Burden of Disease (GBD) 2021 study, the global burden of SAH in 1990 to 2021 was estimated. Moreover, the SAH burden was compared with other diseases, and its associations with 14 individual risk factors were investigated with available data in the GBD 2021 study. The GBD study included the burden estimates of nontraumatic SAH among all ages in 204 countries and territories between 1990 and 2021. EXPOSURES: SAH and 14 modifiable risk factors. MAIN OUTCOMES AND MEASURES: Absolute numbers and age-standardized rates with 95% uncertainty intervals (UIs) of SAH incidence, prevalence, mortality, and disability-adjusted life-years (DALYs) as well as risk factor-specific population attributable fractions (PAFs). RESULTS: In 2021, the global age-standardized SAH incidence was 8.3 (95% UI, 7.3-9.5), prevalence was 92.2 (95% UI, 84.1-100.6), mortality was 4.2 (95% UI, 3.7-4.8), and DALY rate was 125.2 (95% UI, 110.5-142.6) per 100 000 people. The highest burden estimates were found in Latin America, the Caribbean, Oceania, and high-income Asia Pacific. Although the absolute number of SAH cases increased, especially in regions with a low sociodemographic index, all age-standardized burden rates decreased between 1990 and 2021: the incidence by 28.8% (95% UI, 25.7%-31.6%), prevalence by 16.1% (95% UI, 14.8%-17.7%), mortality by 56.1% (95% UI, 40.7%-64.3%), and DALY rate by 54.6% (95% UI, 42.8%-61.9%). Of 300 diseases, SAH ranked as the 36th most common cause of death and 59th most common cause of DALY in the world. Of all worldwide SAH-related DALYs, 71.6% (95% UI, 63.8%-78.6%) were associated with the 14 modeled risk factors of which high systolic blood pressure (population attributable fraction [PAF] = 51.6%; 95% UI, 38.0%-62.6%) and smoking (PAF = 14.4%; 95% UI, 12.4%-16.5%) had the highest attribution. CONCLUSIONS AND RELEVANCE: Although the global age-standardized burden rates of SAH more than halved over the last 3 decades, SAH remained one of the most common cardiovascular and neurological causes of death and disabilities in the world, with increasing absolute case numbers. These findings suggest evidence for the potential health benefits of proactive public health planning and resource allocation toward the prevention of SAH.
Sociodemographic influences on substance use in psychosis in an African cohort.
BACKGROUND: Substance use is common among individuals with psychotic disorders, but limited research exists on the variations in substance use across countries in Africa. This study aims to investigate the frequency of alcohol, tobacco, cannabis, and khat consumption in individuals with bipolar disorder (BD) and schizophrenia (SCZ) across four African countries: South Africa, Ethiopia, Kenya, and Uganda. METHODS: We utilized data from the Neuropsychiatric Genetics of African Populations-Psychosis project, a large case-control study which will soon have genetic data on over 42,000 participants, half with psychosis. Information on substance use was collected using the Alcohol, Smoking and Substance Involvement Screening Test v3 (ASSIST). The outcome was categorized into never (lifetime usage, no), irregular usage (weekly or monthly) and regular (daily use) based on reported frequency in the past three months. Each substance was modeled individually as an outcome in ordinal regression model adjusting for demographic factors of sex, education and country. Stratified analyses were performed to assess country-specific effects. RESULTS: Individuals with BD had significantly higher odds of alcohol consumption compared to those with SCZ. Males showed higher odds of alcohol, tobacco, and khat consumption compared to females. Significant variations in alcohol, tobacco, and cannabis consumption were observed across different study countries. Education level was significantly associated with khat consumption, with higher education levels associated with lower odds of consumption. CONCLUSION: Country and sex-specific differences in substance use behaviors exist in a large-scale African case-control study of people with psychosis. The findings here are in line with previous work regarding sex and regional differences, though they differ from studies conducted in US populations in that minimal evidence was found to support a relationship between level of education and frequency of substance use for any of the substances studied. This suggests that there may be distinct sociodemographic correlates of substance use in Africa and highlights the critical need to consider individuals of diverse ancestry in large-scale studies while also taking into account regional differences when examining substance use behaviors.
African leadership in brain diplomacy: The Yaoundé declaration advances the global brain economy playbook for better brain Health.
Africa, the world's second-largest continent is home to 1.5 billion people, accounting for nearly 20% of the global population, (60% under age 25). By 2050, Africa's population will be 2.5 billion, and by 2035, more young Africans will be entering the workforce each year than in the rest of the world combined. Africa also hosts a rich social, cultural, and geopolitical diversity across its 5 geopolitical zones covering 54 countries. It is the most genetically, culturally, and linguistically diverse region on the planet. However, Africa's contribution to the global economy could be more significant if it urgently embraces the brain economy and leads in the development of new methodologies and approaches which can be exported around the world. In this paper, we explain our strategy to advance the Yaoundé Declaration for the Brain Economy, Brain Health, and Brain Capital. The Declaration has been endorsed by Cameroon's President, His Excellency Paul Biya, and demonstrates African leadership in global brain and society innovations, laying out a roadmap for how Africa can outcompete other economies by deftly deploying brain science-inspired policies and investments. We outline a new economic approach for African jobs, economic growth, sustainability, resilience, health, and well-being. The brain economy offers a broader framework than the current sustainable development goals (SDG) agenda. The Yaoundé Declaration is trans-disciplinary and cross-cutting across sectors: 32 sitting members of government from different sectors having co-authored this paper. It aligns with many aspects of the United Nations Pact for the Future and can accelerate the SDG.
Missed opportunities in early psychosis care: Retrospective chart review of cardiovascular disease monitoring, disengagement and weight changes in a Ghanaian psychiatric hospital
Background Patients with psychosis face an elevated risk of cardiovascular mortality and are more likely to disengage from care. While antipsychotics are essential for treatment, they further increase this risk. Despite this, Ghana lacks a national policy for monitoring cardiovascular risk factors in individuals on antipsychotics. Aims To evaluate disengagement in care and weight changes among newly diagnosed psychotic patients at Accra Psychiatric Hospital, and to inform clinical practice. Method A retrospective review of medical records was conducted for patients newly diagnosed with non-affective psychotic disorders between June 2022 and May 2023. Patients were reviewed for 6 months, with assessments at baseline, 3 months and 6 months. Outcomes included antipsychotic prescription patterns, dropout rates, cardiovascular disease monitoring and weight changes. Descriptive statistics, multinomial logistic regression and linear mixed-effects models were used for analysis. Results The number of patients disengaged from care within the first month was 53.1%, and within 6 months 75.5%; 62.8% received olanzapine at baseline. Weight gain was exponential, with 40% experiencing clinically significant weight gain at 3 months, increasing to 58% at 6 months. Less than 50% of patients had their blood sugar and lipid profiles checked before starting antipsychotics. Higher baseline weight was associated with increased weight over time (β = 0.96, t = 80, P < 0.001, 95% CI 0.93, 0.98). Conclusions High disengagement rates, low cardiovascular disease monitoring and exponential weight gain were observed. Targeted interventions, robust monitoring protocols and further research are needed to improve patient outcomes.
Nutraceuticals: using food to enhance brain health by modulating postnatal neurogenesis in animal models and patient populations
Adult hippocampal neurogenesis, while occurring throughout life, decreases with age and in some neurodegenerative diseases. As decreased hippocampal neurogenesis is correlated with cognitive decline, efforts have been made to increase levels of neurogenesis, either through natural compounds, environmental interventions or novel pharmacological compounds. Nutraceuticals are food products with medical benefits such as antioxidation, anti-inflammation or neuroprotection. There has been increasing interest in these “functional foods” and their active compounds in recent years, providing natural alternatives to de novo pharmaceuticals. This review highlights key nutraceuticals that promote neurogenesis and/or improve cognitive outcomes. By outlining the effects of these compounds in the animal models employed and in clinical populations, we also suggest further investigations. We examine common targets and pathways through which these nutraceuticals are believed to exert pro-neurogenic effects. Most nutraceutical preparations contain multiple components, any of which may exert effects on neurogenesis. Identifying key active compounds in nutraceuticals may enable researchers to better understand their effects and standardize doses across studies. The less stringent regulatory requirements for nutraceuticals can be a double-edged sword. While allowing easier access to the beneficial effects, higher doses of these compounds may have detrimental effects. Hence, research in this field should not only aim to identify the benefits of these compounds but also to identify efficacious and safe dosages for them. Our aims are to provide understanding of nutraceuticals, provide evidence for their benefits on neurogenesis and neurogenesis-related behaviors and finally to summarize potential mechanisms and help guide future work.
Neurofeedback modulation of insula activity via MEG-based brain-machine interface: a double-blind randomized controlled crossover trial.
Insula activity has often been linked to pain perception, making it a potential target for therapeutic neuromodulation strategies such as neurofeedback. However, it is not known whether insula activity is under cognitive control and, if so, whether this activity is consequently causally related to pain. Here, we conducted a double-blind randomized controlled crossover trial to test the modulation of insula activity and pain thresholds using neurofeedback training. Nineteen healthy subjects underwent neurofeedback training for upmodulation and downmodulation of right insula activity using our magnetoencephalography (MEG)-based brain-machine interface. We observed significant differences in insula activity between the upmodulation and downmodulation training sessions. Furthermore, resting-state insula activity significantly decreased following downmodulation training compared to following upmodulation training. Compared with upmodulation training, downmodulation training was also associated with increased pain thresholds, albeit with no significant interaction effect. These findings show that humans can cognitively modulate insula activity as a potential route to develop therapeutic MEG neurofeedback systems for clinical testing. However, the present findings do not provide direct evidence of a causal link between modulation of insula activity and changes in pain thresholds.
Metabolic engineering of stomatal precursor cells enhances photosynthetic water-use efficiency and vegetative growth under water-deficit conditions in Arabidopsis thaliana.
Stomata are epidermal pores that control the exchange of gaseous CO2 and H2O between plants and their environment. Modulating stomatal density can alter this exchange and thus presents a viable target for engineering improved crop productivity and climate resilience. Here, we show that stomatal density in Arabidopsis thaliana can be decreased by the expression of a water-forming NAD(P)H oxidase targeted to stomatal precursor cells. We demonstrate that this reduction in stomatal density occurs irrespective of whether the expressed enzyme is localized to the cytosol, chloroplast stroma or chloroplast intermembrane space of these cells. We also reveal that this decrease in stomatal density occurs in the absence of any measurable impact on the efficiency and thermal sensitivity of photosynthesis, or on stomatal dynamics. Consequently, overexpression plants exhibit a higher intrinsic water-use efficiency due to an increase in CO2 fixed per unit water transpired. Finally, we demonstrate that this enhanced water-use efficiency translates to an improvement in vegetative growth and biomass accumulation under water-deficit conditions. Together, these results thus provide a novel approach for enhancing plant productivity through metabolic engineering of stomatal density.
Bacterial pathogenomics.
Genomes from all of the crucial bacterial pathogens of humans, plants and animals have now been sequenced, as have genomes from many of the important commensal, symbiotic and environmental microorganisms. Analysis of these sequences has revealed the forces that shape pathogen evolution and has brought to light unexpected aspects of pathogen biology. The finding that horizontal gene transfer and genome decay have key roles in the evolution of bacterial pathogens was particularly surprising. It has also become evident that even the definitions for 'pathogen' and 'virulence factor' need to be re-evaluated.
Mutations in γ-aminobutyric acid (GABA) transaminase genes in plants or Pseudomonas syringae reduce bacterial virulence.
Pseudomonas syringae pv. tomato DC3000 is a bacterial pathogen of Arabidopsis and tomato that grows in the apoplast. The non-protein amino acid γ-amino butyric acid (GABA) is produced by Arabidopsis and tomato and is the most abundant amino acid in the apoplastic fluid of tomato. The DC3000 genome harbors three genes annotated as gabT GABA transaminases. A DC3000 mutant lacking all three gabT genes was constructed and found to be unable to utilize GABA as a sole carbon and nitrogen source. In complete minimal media supplemented with GABA, the mutant grew less well than wild-type DC3000 and showed strongly reduced expression of hrpL and avrPto, which encode an alternative sigma factor and effector, respectively, associated with the type III secretion system. The growth of the gabT triple mutant was weakly reduced in Arabidopsis ecotype Landberg erecta (Ler) and strongly reduced in the Ler pop2-1 GABA transaminase-deficient mutant that accumulates higher levels of GABA. Much of the ability to grow on GABA-amended minimal media or in Arabidopsis pop2-1 leaves could be restored to the gabT triple mutant by expression in trans of just gabT2. The ability of DC3000 to elicit the hypersensitive response (HR) in tobacco leaves is dependent upon deployment of the type III secretion system, and the gabT triple mutant was less able than wild-type DC3000 to elicit this HR when bacteria were infiltrated along with GABA at levels of 1 mm or more. GABA may have multiple effects on P. syringae-plant interactions, with elevated levels increasing disease resistance.
Effects of 28-day simvastatin administration on emotional processing, reward learning, working memory, and salivary cortisol in healthy participants at-risk for depression: OxSTEP, an online experimental medicine trial.
BACKGROUND: Statins are among the most prescribed medications worldwide. Both beneficial (e.g. antidepressant and pro-cognitive) and adverse (e.g. depressogenic and cognitive-impairing) mental health outcomes have been described in clinical studies. The underlying neuropsychological mechanisms, whether positive or negative, are, however, not established. Clarifying such activities has implications for the safe prescribing and repurposing potential of these drugs, especially in people with depression. METHODS: In this double-blind, randomized, placebo-controlled experimental medicine study, we investigated the effects of simvastatin on emotional processing, reward learning, working memory, and waking salivary cortisol (WSC) in 101 people at-risk for depression due to reported high loneliness scores (mean 7.3 ± 1.2 on the UCLA scale). This trial was largely conducted during periods of social distancing due to the COVID-19 pandemic (July 2021-February 2023), and we employed a fully remote design within a UK-wide sample. RESULTS: High retention rates, minimal outlier data, and typical main effects of task condition (e.g. emotion) were seen in all cognitive tasks, indicating this approach was comparable to in-person testing. After 28 days, we found no statistically significant differences (F's 0.20) for any of the measures of emotional processing, reward learning, working memory, and WSC. CONCLUSIONS: Study results do not substantiate concerns regarding adverse neuropsychiatric events due to statins and support the safety of their prescribing in at-risk populations. Although other unmeasured cognitive processes may be involved, our null findings are also in line with more recent clinical evidence suggesting statins do not show antidepressant or pro-cognitive efficacy.