Remimazolam attenuates lipopolysaccharide-induced neuroinflammation and cognitive dysfunction.

OBJECTIVE: Remimazolam, a novel benzodiazepine, is widely used as an anesthetic in endoscopic procedures; however, its effects on cognitive function remain unclear, limiting its broader application in general anaesthesia. Neuroinflammation is a well-established key factor in the etiology and progression of cognitive dysfunction, including conditions such as Alzheimer's disease, Parkinson's disease, postoperative delirium, and postoperative cognitive dysfunction. Preclinical studies have demonstrated that remimazolam exerts anti-inflammatory and neuroprotective effects, and clinical reports indicate a reduced incidence of postoperative delirium in patients treated with remimazolam. Nevertheless, whether remimazolam improves cognitive function through its anti-inflammatory properties remains uncertain. This study aimed to investigate the neuroprotective effects of remimazolam and its underlying mechanism in a lipopolysaccharide (LPS)-induced model of neuroinflammation, neuronal injury, and cognitive dysfunction METHODS: C57BL/6 J male mice were administered LPS intraperitoneally to establish a model of neuroinflammation-induced cognitive impairment. A subset of mice received remimazolam via intraperitoneal injection 30 minutes prior to LPS administration. Cognitive performance was evaluated using behavioural tests, including the Morris Water Maze (MWM), Novel Object Recognition (NOR) test, and Open Field Test (OFT). Hippocampal tissues were analyzed by haematoxylin-eosin (HE) staining to assess structural changes. Inflammatory markers, including Interleukin (IL)-6, IL-1ß, and tumor necrosis factor-α, were quantified using enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR. Immunofluorescence was used to detect translocator protein (TSPO) and markers of microglia activation (IBA-1, CD16/32, and CD206). RESULTS: (1) Remimazolam reversed LPS-induced cognitive deficits, as evidenced by shorter spatial exploration latency and increased platform crossings in the MWM, and an elevated recognition index in the NOR test. (2) Remimazolam improved hippocampal morphology, reducing LPS-induced neuronal damage. (3) Remimazolam significantly decreased levels of hippocampal inflammatory cytokines, inhibited microglial activation, promoted M2-type microglia polarization, and increased TSPO expression. CONCLUSION: Remimazolam demonstrated neuroprotective and anti-neuroinflammatory effects in a mouse model of LPS-induced cognitive impairment. These effects are likely mediated through the regulation of TSPO, which inhibits microglial activation and promotes the polarization of microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype.

Later-Life Cognitive Trajectories and Risk of Death: Results from a 6-Year Longitudinal Study of 7082 Chinese.

BACKGROUND AND OBJECTIVES: To identify cognitive decline trajectories in a Chinese elderly population, explore the associations between these trajectories and mortality, and further identify risk factors related to certain trajectories of cognitive decline. DESIGN: Prospective cohort study. SETTING: The group-based trajectory modeling and Cox proportional hazards models were conducted to explore the association between cognitive trajectory groups and mortality, while multinomial logistic regression models were constructed to estimate potential risk factors. PARTICIPANTS: We included 7082 participants aged 65 years or above in three consecutive but non-overlapping cohorts of the Chinese Longitudinal Healthy Longevity Survey with the Chinese version of the Mini-Mental State Examination up to 6 years. Participants were subsequently followed for a median (IQR) of 2.89 (1.38-3.12) years to obtain their survival status and date of death. MEASUREMENTS: Chinese version of the Mini-Mental State Examination was used to measure participants' cognitive function. RESULTS: Through use of group-based trajectory modeling, we determined three cognitive trajectory groups. Then, after adjusting for confounding factors, we found a monotonic and positive association between cognitive decline and mortality risk. Meanwhile, the association varied among elderly populations in different age groups and BMI categories, but did not differ by sex, smoking, drinking and exercising. Older seniors, females and those with poorer baseline cognitive function and less social participation tended to be more likely to be in the unfavorable trajectory groups. CONCLUSION: We found that the faster the cognitive decline, the higher the mortality, especially among those aged 65-79 years and those overweight. Our findings suggested the importance of implement better monitoring of the cognitive function of the elderly population.

Impact of psilocybin on cognitive function: A systematic review.

Psilocybin is a classic psychedelic with demonstrated preliminary clinical efficacy in a range of psychiatric disorders. Evaluating the impact of psilocybin on cognitive function is essential to unravel its potential benefits and risks. In this systematic review, we assessed psilocybin's effect on cognitive function through a comprehensive search of electronic databases from inception to January 2024, identifying 20 articles involving 2,959 participants. While 85% of studies were conducted in healthy volunteers, most of these studies (85%) used macrodoses, ranging from 45 µg/kg to 30 mg/70 kg. Various cognitive aspects were evaluated and yielded mixed results. Global cognitive function, and processing speed remained mostly unchanged in healthy individuals; However, a limited number of studies reported improvements in certain areas such as sustained attention, working memory, and executive function especially in patients with treatment-resistant depression (TRD). Emotional processing was positively modified, particularly in TRD patients. Psilocybin was observed to enhance emotional empathy without significantly altering cognitive empathy and social cognition. Cognitive flexibility and creative cognition were noted to initially decline but could potentially improve over time. Additionally, with respect to learning and memory skills, psilocybin showed promise in improving specific memory types such as semantic associations and associative learning, while its effects on episodic and verbal memory have been less pronounced compared to other cognitive enhancers. The observed mixed findings underscore the complexity of psilocybin's cognitive influence. Further research is essential to provide a clearer understanding of psilocybin's impact on cognitive domains and to guide the development of safe and effective interventions.

Clinical efficacy of low-intensity pulsed ultrasound in Parkinson's disease with cognitive impairment.

OBJECTIVE: Low-intensity pulsed ultrasound (LIPUS), is a new technique for invasive brain stimulation and modulation that has emerged recently, but the effects in Parkinson's disease with cognitive impairment (PD-CI) have been less observed. In this study, we collected 56 patients with PD-CI who were continuously treated with LIPUS for 8 weeks, and observed the clinical efficacy of LIPUS on PD-CI patients by comparing with the Sham stimulation continuous treatment. METHODS: Fifty-six PD-CI patients were divided into the Sham group (given Sham stimulation on top of conventional medication, n = 28) and the LIPUS group (given LIPUS stimulation on top of conventional medication, n = 28), and both groups continued treatment for 8 weeks. Post-treatment efficacy and pre- and post-treatment cognitive function [Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA)], emotional state [Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI)], quality of life [Unified Parkinson's Disease Rating Scale (UPDRS), 39-item Parkinson's Disease Questionnaire (PDQ-39)], and serologic indices [5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA)] were compared. RESULTS: The total effective rate of the LIPUS group was higher versus that of the Sham group. In both groups, MMSE and MoCA scores increased; BDI and BAI scores decreased; UPDRS and PDQ-39 scores were reduced; the levels of 5-HT, NE, and DA were elevated. The above changes were more pronounced in the LIPUS group (all P < 0.05). CONCLUSION: The application of LIPUS on PD-CI could ameliorate patients' cognitive function, emotional state and quality of life, and regulate and optimize neurotransmitter expression levels.

Self-Employment Transitions and Health Outcomes in Later Life: Evidence From China.

Background and Objectives: Self-employment is a vital alternative to waged employment for older workers. Recent research has shown that employment transitions frequently occur when individuals approach retirement. However, evidence of how older people's health changes when they switch between self and waged employment is lacking, particularly outside Western contexts. To address this research gap, we explored the health impact of employment transitions for the older working population in China by hukou (urban or rural household registration status), region, and education. Research Design and Methods: We employed fixed effect models to examine the impact of employment transitions on cognitive, mental, and physical health and life satisfaction drawing on data from four waves (2011, 2013, 2015, and 2018) of the China Health and Retirement Longitudinal Study (N = 4,606). Given China's unique context, we analyzed the results of agricultural and nonagricultural work separately. Results: Individuals transitioning into or remaining in self-employment had lower self-rated health and life satisfaction than those remaining in waged employment. There was no significant difference in cognitive functioning or depressive symptoms. Additionally, those who transitioned from self-employment into waged employment rated their health worse than those who remained in waged employment. The health impacts were more apparent for agricultural than nonagricultural self-employment, particularly for older workers living in urban regions with rural hukou and lower education levels. Discussion and Implications: Most older Chinese transitioning into or staying self-employed are or were pushed into self-employment due to their low human capital and socioeconomic status, which affects their subsequent health. Pension reform and policies supporting older adults to stay in the workforce could help close the economic and health gaps between rural and urban older adults.

Cognitive function in dyslipidemia patients: exploring the impact of statins.

Background: Evidence regarding the relationship between the use of statins and cognitive outcomes presents varying findings. This study aims to analyze the relationship between sustained statin use and cognitive performance in dyslipidemia patients. Methods: This study presents findings from the Beijing Ageing Brain Rejuvenation Initiative (BABRI) study, in which a cohort of community-dwelling dyslipidemia patients (Entire sample, N = 1,062, aged 50-86) was recruited. Participants were divided into two groups based on their sustained use statins (Statins group, N = 677) or not use any lipid-lowering agents (Untreated group, N = 385). Furthermore, the entire sample was stratified by age into the middle-aged sample (N = 451) and the older people sample (N = 611), following a similar categorization based on statin application. ANCOVA was used to evaluate the relationship between sustained statin use and cognitive function. Results: Overall, in the total sample, the statins group demonstrated better cognition in overall cognition, memory, visuospatial ability, attention, executive function, and language domains compared to the untreated group. Moreover, the statins group only showed better performance in attention among the middle-aged sample. In the older people sample, statins group exhibited superior cognitive performance across various cognitive domains compared to untreated group. Conclusion: Among dyslipidemia patients in Beijing community, sustained statin users exhibited superior cognitive function across all domains compared to untreated individuals, with particularly noticeable improvements among those aged 65 and above. These findings underscore the protective effect of statins on cognitive function in dyslipidemia patients, highlighting significant benefits for the older people population.

Investigating the Correlation Between Cognitive Function and Fasting Blood Sugar, Fasting Insulin Level and Insulin Sensitivity in Patients With Multiple Sclerosis.

INTRODUCTION: There has been a surge in interest in identifying the factors that impact cognitive impairment (CI) in patients with multiple sclerosis (MS). The purpose of our study was to examine the correlation between fasting blood sugar (FBS), fasting insulin level, as well as insulin sensitivity and cognitive function in patients with MS. MATERIAL AND METHODS: A total of 85 patients with MS enrolled in this cross-sectional study. Insulin sensitivity (IS) was determined using the quantitative insulin sensitivity check index (Quicki) formula. Cognitive function was evaluated using the Persian version of the Brief International Cognitive Assessment for MS (BICAMS). Spearman correlation test was employed to examine the correlation between cognition and FBS, insulin and IS. RESULTS: The mean ± SD age of the participants was 39.4 ± 10.2 years, and 62 (72.9%) were female. The participants had a FBS level of 87.05 ± 11.73 mg/dL, insulin level of 10.14 ± 7.57 µU/mL and a Quicki index of 0.36 ± 0.05. A higher score on the BVMT-R and BVMT-R-Delayed subtests showed a significant negative correlation with FBS (r: -0.32; p: 0.003 and r: -0.31; p: 0.004, respectively). Conversely, a significant negative correlation (r: -0.24; p: 0.031) was observed between higher fasting insulin levels and the CVLT_II score. IS showed a positive correlation with the CVLT-II (r: 0.24; p: 0.027) and BVMT_R (r: 0.21; p: 0.054) subtests. CONCLUSION: Our data indicate that elevated fasting glucose, developed fasting insulin levels and reduced insulin sensitivity may serve as potential predictors for CI in patients with MS.

Cognitive Benefits of Hearing Aids in Elderly Indian Population: A Longitudinal Study.

Age-related hearing loss is common among older individuals and is linked to cognitive impairment and a decrease in overall quality of life. Although hearing aids enhance auditory capabilities, their influence on cognitive performance in the Indian context has not been thoroughly investigated. This study investigates the cognitive benefits of hearing aids in elderly Indian patients with age-related hearing loss. A prospective cohort study was conducted at a tertiary care centre between January 2021 and December 2022. The study included 200 elderly patients who were fitted with behind-the-ear (BTE) or receiver-in-canal (RIC) hearing aids. The assessment of cognitive function was conducted using two standardised tests: the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). The assessment of quality of life was conducted using the WHOQOL-OLD questionnaire, while hearing acuity was examined by pure-tone audiometry and speech perception tests. Data were collected at baseline, 6 months, and 18 months. Multiple linear regression analysis identified predictors of cognitive outcomes. There were significant enhancements in MMSE, MoCA, HHIE, and WHOQOL-OLD scores across the 18-month duration (p < 0.001). The pure-tone audiometry thresholds and speech perception scores demonstrated significant improvement (p < 0.001). Regression analysis indicated that baseline cognitive function, hearing ability, and quality of life were significant predictors of cognitive outcomes at 18 months. No severe cognitive impairment or other confounding severe medical conditions were reported. This study revealed that the use of hearing aids has a substantial positive impact on cognitive function, quality of life, and hearing ability in the older Indian population suffering from age-related hearing loss. Timely intervention and the availability of hearing aids are essential for improving cognitive health and overall well-being in this demographic. Future study should look into the consequences and influence of various hearing aid models. Supplementary Information: The online version contains supplementary material available at 10.1007/s12070-024-04939-7.

A meta-analysis of the effects of transcranial direct current stimulation combined with cognitive training on working memory in healthy older adults.

Background: Working memory (WM) loss, which can lead to a loss of independence, and declines in the quality of life of older adults, is becoming an increasingly prominent issue affecting the ageing population. Transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique, is emerging as a potential alternative to pharmacological treatments that shows promise for enhancing WM capacity and May enhance the effects of cognitive training (CT) interventions. Objective: The purpose of this meta-analysis was to explore how different tDCS protocols in combination with CT enhanced WM in healthy older adults. Methods: Randomized controlled trials (RCTs) exploring the effects of tDCS combined with CT on WM in healthy older adults were retrieved from the Web of Science, PubMed, Embase, Scopus and the Cochrane Library databases. The search time period ranged from database inception to January 15, 2024. Methodological quality of the trials was assessed using the risk-of-bias criteria for RCTs from the Cochrane Collaboration Network, and RevMan 5.3 (Cochrane, London, United Kingdom) was used for the meta-analysis of the final literature outcomes. Results: Six RCTs with a total of 323 participants were ultimately included. The results of the meta-analysis show that tDCS combined with CT statistically significantly improves WM performance compared to the control sham stimulation group in healthy older adults [standard mean difference (SMD) = 0.35, 95% CI: 0.11-0.59, I 2 = 0%, Z = 2.86, p = 0.004]. The first subgroup analysis indicated that, when the stimulus intensity was 2 mA, a statistically significant improvement in WM performance in healthy older adults was achieved (SMD = 0.39, 95% CI: 0.08-0.70, I 2 = 6%, Z = 2.46, p = 0.01). The second subgroup analysis showed that long-term intervention (≥ 10 sessions) with tDCS combined with CT statistically significantly improved WM compared to the control group in healthy older adults (SMD = 0.72, 95% CI: 0.22-1.21, I 2 = 0%, Z = 2.85, p = 0.004). Conclusion: tDCS combined with CT statistically significantly improves WM in healthy older adults. For the stimulus parameters, long-term interventions (≥ 10 sessions) with a stimulation intensity of 2 mA are the most effective.

Neuropsychological impact of Sanda training on athlete attention performance.

Background: Sanda, a martial art that primarily involves punching, kicking, and throwing techniques, requires athletes to maintain high levels of concentration during combat. Sanda principally involves striking the opponent to secure victory, with trauma frequently occurring to the head; however, it remains unclear whether prolonged training enhances or impairs the athletes' attentional capacities. This study aimed to investigate the impact of Sanda training on athletes' attention by employing attention network tests. Methods: A retrospective analysis was conducted on 37 professional Sanda athletes from a certain sports academy; 38 college students from the same institution majoring in physical education were recruited as the control group. Control participants had no prior experience in Sanda training, and the Sanda and control groups were matched in terms of sex, age, and education level. The Attention Network Test (ANT) was administered to both groups to compare differences in efficiency across the alerting, orienting, and executive control networks. Results: Compared to the control group, the Sanda athletes exhibited significantly higher executive control network efficiency values and executive control network efficiency ratios (P < 0.05). There were no significant differences between the Sanda group and the control group regarding the efficiency values of the alerting and orienting networks (P > 0.05). Additionally, total accuracy and total reaction time between the Sanda athletes and control participants showed no statistically significant differences (P > 0.05). Conclusion: Sanda practice has detrimental effects on attention, including a decrease in the efficiency of the executive control network and a prolongation of the total reaction time. Therefore, athletes should improve attention training and use head protection to prevent frequent head impacts during training.

Association between a body shape index and cognitive impairment among US older adults aged 40 years and above from a cross-sectional survey of the NHANES 2011-2014.

Purpose: This research aimed to assess the correlation between the Adjusted Body Shape Index (ABSI) and the presence of abdominal aortic calcification (AAC) among middle-aged and older American adults. Methods: Employing a cross-sectional design, this study analyzed data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES), focusing on 3077 participants aged 40 and above. AAC detection was conducted using dual-energy X-ray absorptiometry (DXA). ABSI was determined based on waist circumference (WC), weight, and height data. The association between ABSI and AAC was examined through multiple linear regression, smoothed curve analysis, threshold effect evaluation, subgroup analysis, and interaction testing. Results: The study encompassed 3077 individuals aged 40 and above. Findings indicated a noteworthy positive relationship between ABSI and AAC when adjusting various covariates. Analysis of threshold effects identified a K-point at 0.0908, showing no significant effect to its left but a significant effect to its right. Further, subgroup and interaction analyses highlighted the ABSI-AAC connection specifically within different age groups and among individuals with diabetes. Conclusion: Higher ABSI was correlated with higher AAC score.

Systematic Review and Meta-Analysis Confirm the Moderate Efficacy of High-Frequency r-TMS in Alzheimer's Disease: Mediating Effects of Anhedonia-Apathy and Add-On Motor-Cognitive Excersizes.

OBJECTIVES: Alzheimer's disease (AD) presents a major global health issue of significant socio-economic impact. Pharmacological treatments for AD have limited efficacy, prompting the exploration of alternative therapies, such as repetitive transcranial magnetic stimulation (rTMS), a promising non-invasive technique to enhance cognitive function in AD patients. Our systematic review and meta-analysis aim to evaluate the efficacy of rTMS in relation to cognitive function in AD patients, identify optimal rTMS stimulation parameters, and understand the underlying neural mechanisms. METHODS: We conducted a comprehensive literature search in PubMed using predefined search terms to identify original research articles investigating the effects of rTMS on cognitive function in AD patients. We selected only randomized controlled trials (RCTs) with sufficient quantitative data for comparing active rTMS to the sham-coil treatment, and then performed a random effects meta-analysis using standardized mean differences (SMDs) to synthesize the effects across studies. RESULTS: The systematic review included 22 studies, among which 14 RCTs met our criteria for meta-analysis. High-frequency rTMS, particularly targeting the dorsolateral prefrontal cortex (DLPFC), evoked significant cognitive improvements in AD patients, with a moderate positive effect size of rTMS on cognitive function (Hedges' g=0.580, 95% CI [0.268, 0.892], p<0.001), albeit with substantial heterogeneity (I²=59%). Funnel plot asymmetry and Egger's test suggested a potential publication bias, but fail-safe N analysis indicated a robust finding. Moreover, anhedonia-apathy symptoms and motor-cognitive exercises mediated the efficacy of tTMS in ameliorating cognitive functioning across several studies. CONCLUSION: rTMS demonstrates moderate efficacy in improving cognitive function in AD-patients, most distinctly with high-frequency rTMS stimulation protocols targeting the DLPFC area. The meta-analysis support rTMS as a viable therapeutic intervention for cognitive enhancement in AD. Future promising research should focus on personalized treatment strategies targeting mediating factors, baseline connectivity patterns, and TMS-induced neuroplasticity in AD.

Melatonin attenuates intermittent hypoxia-induced cognitive impairment in aged mice: The role of inflammation and synaptic plasticity.

Intermittent hypoxia (IH), a major pathophysiologic alteration in obstructive sleep apnea syndrome (OSAS), is an important contributor to cognitive impairment. Increasing research suggests that melatonin has anti-inflammatory properties and improves functions related to synaptic plasticity. However, it is unclear whether melatonin has a protective effect against OSAS-induced cognitive dysfunction in aged individuals and the involved mechanisms are also unclear. Therefore, in the study, the effects of exposure to IH alone and IH in combination with daily melatonin treatment were investigated in C57BL/6 J mice aged 18 months. Assessment of the cognitive ability of mice in a Morris water maze showed that melatonin attenuated IH-induced impairment of learning and memory in aged mice. Enzyme-linked immunosorbent assay, polymerase chain reaction, and western blotting molecular techniques showed that melatonin treatment reduced the levels of the proinflammatory cytokines, interleukin-1ß, interleukin-6, and tumor necrosis factor-α, decreased the levels of NOD-like receptor thermal protein domain associated protein 3 and nuclear factor kappa-B, lowered the levels of ionized calcium-binding adapter molecule 1 and glial fibrillary acidic protein, and increased the levels of the synaptic proteins, activity-regulated cytoskeleton-associated protein, growth-associated protein-43, postsynaptic density protein 95, and synaptophysin in IH-exposed mice. Moreover, electrophysiological results showed that melatonin ameliorated the decline in long-term potentiation induced by IH. The results suggest that melatonin can ameliorate IH-induced cognitive deficits by inhibiting neuroinflammation and improving synaptic plasticity in aged mice.

Telomere length and 4-year changes in cognitive function in an older Mediterranean population at high risk of cardiovascular disease.

BACKGROUND: Cognitive decline, a common process of brain ageing, has been associated with telomere length (TL). Delving into the identification of reliable biomarkers of brain ageing is essential to prevent accelerated cognitive impairment. METHODS: We selected 317 non-smoking 'Prevención con Dieta Mediterránea-Plus' (PREDIMED-Plus) participants (mean age, 65.8 ± 5.0 years) with metabolic syndrome from two trial centres who were following a lifestyle intervention. We measured TL and cognitive function at baseline and after 3 and 4 years of follow-up, respectively. Associations between baseline or 3-year changes in TL and baseline or 4-year changes in cognitive function were analysed using multivariable regression models. RESULTS: Baseline TL was not associated with baseline cognitive performance. Nevertheless, longer baseline TL was associated with improved 4-year changes in the Executive Function domain (ß: 0.29; 95%CI: 0.12 to 0.44; P < 0.001) and the Global Cognitive Function domain (ß: 0.19; 95%CI: 0.05 to 0.34; P = 0.010). Besides, a positive association was found between longer baseline TL and improved 4-year changes in the animal version of the Verbal Fluency Test (ß: 0.33; 95%CI: 0.12 to 0.52; P = 0.002). By contrast, 3-year changes in TL were not associated with changes in cognitive function after 4 years. CONCLUSIONS: Longer baseline TL could protect from cognitive decline and be used as a useful biomarker of brain ageing function in an older Mediterranean population at risk of cardiovascular disease and cognitive impairment.

Chronic Corticosterone Administration-Induced Mood Disorders in Laboratory Rodents: Features, Mechanisms, and Research Perspectives.

Mood disorders mainly affect the patient's daily life, lead to suffering and disability, increase the incidence rate of many medical illnesses, and even cause a trend of suicide. The glucocorticoid (GC)-mediated hypothalamus-pituitary-adrenal (HPA) negative feedback regulation plays a key role in neuropsychiatric disorders. The balance of the mineralocorticoid receptor (MR)/glucocorticoid receptor (GR) level contributes to maintaining the homeostasis of the neuroendocrine system. Consistently, a chronic excess of GC can also lead to HPA axis dysfunction, triggering anxiety, depression, memory loss, and cognitive impairment. The animal model induced by chronic corticosterone (CORT) administration has been widely adopted because of its simple replication and strong stability. This review summarizes the behavioral changes and underlying mechanisms of chronic CORT administration-induced animal models, including neuroinflammatory response, pyroptosis, oxidative stress, neuroplasticity, and apoptosis. Notably, CORT administration at different doses and cycles can destroy the balance of the MR/GR ratio to make dose-dependent effects of CORT on the central nervous system (CNS). This work aims to offer an overview of the topic and recommendations for future cognitive function research.

The Association of the Oral Microbiota with Cognitive Functioning in Adolescence.

Background: A growing body of research supports the role of the microbial communities residing in the digestive system in the host's cognitive functioning. Most of these studies have been focused on the gut microbiome and its association with clinical phenotypes in middle-aged and older adults. There is an insufficiency of population-based research exploring the association of normative cognitive functioning with the microbiome particularly with the oral microbiota. Methods: In this study, using metagenomics and metabolomics, we characterized the salivary microbiome diversity in a sample of 51 males of Hispanic and African American origin aged 12-18 years and explored the associations between the microbiome and the youths' cognitive performance captured with the Kaufman Assessment Battery for Children II (KABC-II). Results: Several bacterial species of the oral microbiota and related metabolic pathways were associated with cognitive function. In particular, we found negative associations between indicators of general intelligence and the relative abundance of Bacteroidetes and Lachnospiraceae and positive associations with Bifidobacteriaceae and Prevotella histicola sp. Among metabolic pathways, the super pathways related to bacterial cell division and GABA metabolism were linked to cognitive function. Conclusions: The results of our work are consistent with the literature reporting on the association between microbiota and cognitive function and support further population work to elucidate the potential for a healthy oral microbiome to improve cognitive health.

Grip strength and depressive symptoms in Chinese middle-aged and older adults: the mediating effects of cognitive function.

Objective: This study investigates the associations and mediating pathways between grip strength, cognitive function, and depression in middle-aged and elderly individuals in China. Methods: Utilizing data from the 2011 China Health and Retirement Longitudinal Study (CHARLS), we employed logistic regression and mediation analysis to examine the relationships and mediating factors between grip strength, cognitive function, and depression, while adjusting for potential confounders. Results: The study included 6,841 participants, of whom 1,734 (25.35%) exhibited symptoms of depression. Our findings indicate that weak grip strength is significantly associated with an increased risk of depression (OR: 1.57, 95% CI: 1.32-1.87) among the middle-aged and elderly population. Conversely, good cognitive function was found to be protective against depression (OR: 0.94, 95% CI: 0.93-0.95). Grip strength indirectly affected depression through cognitive function, accounting for 9.4% of the total effect (ß = -0.008, 95% CI [-0.013, -0.004]). This mediating effect was 23.8% in men (ß = -0.013, 95% CI [-0.020, -0.007]); and 23.2% in those aged 60 years and over (ß = -0.015, 95% CI [-0.022, -0.009]). Conclusion: This study highlights that weak grip strength increases risk of depressive symptoms, and adequate cognitive function can mitigate the association between weak grip strength and an increased risk of depression among middle-aged and elderly individuals in China. Psychological care for elder adults with weak grip strength and poor cognitive function should be strengthened.

Sources of perceived social support and cognitive function among older adults: a longitudinal study in rural China.

Background: Studies have shown the positive impact of perceived social support on cognitive function among older adults in rural areas. However, existing studies often overlook the impact of different support sources. This study aimed to explore the relationship between the diverse sources of perceived social support and cognitive function. Methods: Participants were drawn from the Guizhou Rural Older Adults' Health Study (HSRO) in China. We included 791 participants who participated in a baseline survey in 2019 and a 3-year follow-up survey. Perceived social support was investigated from the six main sources (friend, relative, children, spouse, sibling, and neighbor). Hierarchical linear regression models were used to observe the effects of diverse sources of perceived social support and their combinations on cognitive function. Results: Cognitive function was positively associated with perceived support from children, friends, and neighbors. A positive association was found between cognitive function and increases in each additional source [ß = 0.75 (95%CI: 0.51, 0.98), p < 0.001]. Older adults who perceived support from both children and friends showed better cognitive function [ß = 2.53 (95%CI: 1.35, 3.72), p < 0.001]. The perception of support from spouse, siblings, and relatives did not show a statistically significant association with cognitive function among older adults in rural areas. Conclusion: This study found that the association between different sources of perceived social support and cognitive function was varied. This study provides scientific evidence that personalized support strategies may benefit in promoting cognitive health in rural older adults.

Hippocampal iron overload and spatial reference memory impairment: Insights from a rat model.

BACKGROUND: Brain iron overload may induce neuronal death and lead to cognitive impairment. The hippocampus is a critical limbic structure involved in memory. This study aimed to investigate iron overload and its role in hippocampal damage and memory impairment using a rat model. METHODS: Young rats (2 weeks old) received intraperitoneal injections of high-dose iron solution (Group H, n = 10), low-dose iron solution (Group L, n = 10) and normal saline as control (Group D, n = 5). The Morris water maze (MWM) test was performed on all rats to evaluate their spatial reference memory by assessing their escape latency time and number of platform crossing. The iron content and neuronal damage in hippocampal tissue sections of the rats were assessed semi-quantitatively using diaminobenzidine (DAB)-enhanced Perl's Prussian blue (PPB) staining, and their correlation with spatial reference memory performance was evaluated. RESULTS: The escape latency in Group H was significantly longer compared to Groups L and D (P < 0.05). The number of platform crossings was significantly lower in Group H than in Group L or D (P < 0.001). The neuronal cells in Group H had more brown iron deposits than those of Groups L and D. There were significant correlations between the severity of structural damage in the hippocampal tissue and the number of platform crossings (P1 = 0.001 for Group H; P2 = 0.043 for Group L). CONCLUSION: This study showed an association between hippocampal iron-induced structural damage and spatial reference memory impairment in a rat model. This work should advance our understanding of hippocampal iron overload on cognitive functioning.