Obesity in aging exacerbates blood-brain barrier disruption, neuroinflammation, and oxidative stress in the mouse hippocampus: effects on expression of genes involved in beta-amyloid generation and Alzheimer's disease

Neuropathological links between T2DM and LOAD: systematic review and meta-analysis

Recent decades have described parallel neuropathological mechanisms increasing the risk for developing late-onset Alzheimer's dementia (LOAD) in type 2 diabetes mellitus (T2DM); however, still little is known of the role of diabetic encephalopathy and brain atrophy in LOAD. The aim of this systematic review is to provide a comprehensive view on diabetic encephalopathy/cerebral atrophy, taking into account neuroimaging data, neuropathology, metabolic and endocrine mechanisms, amyloid formation, brain perfusion impairments, neuroimmunology, and inflammasome activation. Key switches were identified, to further meta-analyze genomic candidate loci and epigenetic modifications. For the qualitative meta-analysis of genomic bases extracted, human linkage studies were examined; for epigenetic mechanisms, data from both human and animal studies are described. For the systematic review of pathophysiological mechanisms, 1,259 publications were evaluated and 93 gene loci extracted for candidate risk linkages. Sixty-six publications were evaluated for genomic association and descriptions of epigenomic modifications. Overall accumulated results highlight the insulin signaling system, vascular markers, inflammation and inflammasome pathways, amylin interactions, and glycosylation mechanisms. The protocol was registered with PROSPERO (ID: CRD42023440535).

Investigation of the mechanism of Buyang Huanwu decoction in improving learning and memory impairment in Alzheimer's disease mice based on lipidomics

In this study, a lipid disorder Alzheimer's disease (AD) model was developed with high-fat diet and D-galactose injected intraperitoneally (HFD & D-gal) to evaluate the activities of Buyang Huanwu Decoction (BYHWD) compared with donepezil hydrochloride. The learning and memory abilities of BYHWD were evaluated by Morris water maze test (MWM). The lipid levels in serum, histopathology, and immunohistochemistry of hyperphosphorylated tau protein in hippocampal neurons were conducted to prove the therapy effects of BYHWD. After the identification of constituents absorbed into the brain using LC-MS, UPLC-TQ-MS was employed to analyze endogenous lipid metabolites in the hippocampi of mice. Based on the validated differential markers identified through lipidomics analysis, we further substantiated potential therapeutic pathway of BYHWD through the application of molecular docking technology. The mechanism underlying BYHWD was subsequently confirmed by palmitic acid-injured HT22 cells. The results showed that BYHWD significantly improved the cognitive deficits and regulated the lipid levels of HFD & D-gal mice. BYHWD also protected the neuronal cell condition of hippocampal neurons, increased the density of dendritic spines, and reduced the expression of P-tau. Lipidomics revealed that 41 differential lipid metabolites were retuned after BYHWD administration, and this change may be related to the PPARγ pathway. Calycosin-7-glucoside showed good interaction with PPARγ in vivo composition analysis. Calycosin-7-glucoside increased the mRNA expression levels of lipid metabolism-related enzymes and PPARγ, as well as the expression of PPARγ protein in vitro study. BYHWD activated the PPARγ pathway to induce peroxisome proliferation and regulated lipid metabolism disorders in the AD mice brain.

Peripheral Inflammation and Insulin Resistance: Their Impact on Blood-Brain Barrier Integrity and Glia Activation in Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory impairment, and synaptic dysfunction. The accumulation of amyloid beta (Aβ) plaques and hyperphosphorylated tau protein leads to neuronal dysfunction, neuroinflammation, and glial cell activation. Emerging evidence suggests that peripheral insulin resistance and chronic inflammation, often associated with type 2 diabetes (T2D) and obesity, promote increased proinflammatory cytokines, oxidative stress, and immune cell infiltration. These conditions further damage the blood-brain barrier (BBB) integrity and promote neurotoxicity and chronic glial cell activation. This induces neuroinflammation and impaired neuronal insulin signaling, reducing glucose metabolism and exacerbating Aβ accumulation and tau hyperphosphorylation. Indeed, epidemiological studies have linked T2D and obesity with an increased risk of developing AD, reinforcing the connection between metabolic disorders and neurodegeneration. This review explores the relationships between peripheral insulin resistance, inflammation, and BBB dysfunction, highlighting their role in glial activation and the exacerbation of AD pathology.

Understanding Cognitive Decline in Aging: Mechanisms and Mitigation Strategies - A Narrative Review

Cognitive decline is a natural process that accompanies aging. In some cases, such as in sarcopenia-burdened or diseased older adults, the disease course may be more rapid. Declining cognitive function is associated with changes in the central nervous system per se or peripheral triggers that impair cognition. This review discusses issues related to central, central-peripheral, and peripheral factors that enhance cognitive deterioration, such as cortical thickness, cerebral white matter structure and function, blood-brain barrier (BBB) disruption, insulin resistance, inflammation, and vascular dysfunction. BBB permeability appears to be a critical point for factors associated with aging that may accelerate cognitive decline. Thus, we provide an in-depth analysis of the central-peripheral crosstalk. Additionally, we discuss high-intensity interval training (HIIT) as a promising strategy to counteract changes that accompany the aging process. Resistance (RHIIT) and aerobic (AHIIT) may be beneficial for cognitive health among the elderly, but their lack of empirical confirmation is a huge gap in the research.

Risk Factors, Pathological Changes, and Potential Treatment of Diabetes-Associated Cognitive Dysfunction

BACKGROUND

Diabetes is a prevalent public health issue worldwide, and the cognitive dysfunction and subsequent dementia caused by it seriously affect the quality of life of patients.

METHODS

Recent studies were reviewed to provide a comprehensive summary of the risk factors, pathogenesis, pathological changes and potential drug treatments for diabetes-related cognitive dysfunction (DACD).

RESULTS

Several risk factors contribute to DACD, including hyperglycemia, hypoglycemia, blood sugar fluctuations, hyperinsulinemia, aging, and others. Among them, modifiable risk factors for DACD include blood glucose control, physical activity, diet, smoking, and hypertension management, while non-modifiable risk factors include age, genetic predisposition, sex, and duration of diabetes. At the present, the pathogenesis of DACD mainly includes insulin resistance, neuroinflammation, vascular disorders, oxidative stress, and neurotransmitter disorders.

CONCLUSIONS

In this review, we provide a comprehensive summary of the risk factors, pathogenesis, pathological changes and potential drug treatments for DACD, providing information from multiple perspectives for its prevention and management.

Murine Non-Transgenic Models of Alzheimer's Disease Pathology: Focus on Risk Factors

Alzheimer's disease (AD) represents a significant challenge among neurodegenerative disorders, as effective treatments and therapies remain largely undeveloped. Despite extensive research efforts employing various methodologies and diverse genetic models focused on amyloid-β (Aβ) pathology, the research for effective therapeutic strategies remains inconclusive. The key pathological features of AD include Aβ senile plaques, neurofibrillary tangles (NFTs), and the activation of neuroinflammatory pathways. Presently, investigations into AD and assessing potential treatments predominantly utilize Aβ transgenic models. Conversely, non-transgenic models may provide valuable insights into the multifaceted pathological states associated with AD. Thus, these models may serve as practical complementary tools for evaluating therapeutic and intervention strategies, since the primary AD risk factors are most frequently modeled. This review aims to critically assess the existing literature on AD non-transgenic models induced by streptozotocin, scopolamine, aging, mechanical stress, metals, and dietary patterns to enhance their application in AD research.

Chronic β3 adrenergic agonist treatment improves neurovascular coupling responses, attenuates blood-brain barrier leakage and neuroinflammation, and enhances cognition in aged mice

Microvascular endothelial dysfunction, characterized by impaired neurovascular coupling, reduced glucose uptake, blood-brain barrier disruption, and microvascular rarefaction, plays a critical role in the pathogenesis of age-related vascular cognitive impairment (VCI). Emerging evidence points to non-cell autonomous mechanisms mediated by adverse circulating milieu (an increased ratio of pro-geronic to anti-geronic circulating factors) in the pathogenesis of endothelial dysfunction leading to impaired cerebral blood flow and cognitive decline in the aging population. In particular, age-related adipose dysfunction contributes, at least in part, to an unfavorable systemic milieu characterized by chronic hyperglycemia, hyperinsulinemia, dyslipidemia, and altered adipokine profile, which together contribute to microvascular endothelial dysfunction. Hence, in the present study, we aimed to test whether thermogenic stimulation, an intervention known to improve adipose and systemic metabolism by increasing cellular energy expenditure, could mitigate brain endothelial dysfunction and improve cognition in the aging population. Eighteen-month-old C57BL/6J mice were treated with saline or β3-adrenergic agonist (CL 316, 243, CL) for 6 weeks followed by functional analysis to assess endothelial function and cognition. CL treatment improved neurovascular coupling responses and rescued brain glucose uptake in aged animals. In addition, CL treatment also attenuated blood-brain barrier leakage and associated neuroinflammation in the cortex and increased microvascular density in the hippocampus of aged mice. More importantly, these beneficial changes in microvascular function translated to improved cognitive performance in aged mice. Our results suggest that β3-adrenergic agonist treatment improves multiple aspects of cerebromicrovascular function and can be potentially repurposed for treating age-associated cognitive decline.

Altered cognitive function in obese patients: relationship to gut flora

Obesity is a risk factor for non-communicable diseases such as cardiovascular disease and diabetes, which are leading causes of death and disability. Today, China has the largest number of overweight and obese people, imposing a heavy burden on China's healthcare system. Obesity adversely affects the central nervous system (CNS), especially cognitive functions such as executive power, working memory, learning, and so on. The gradual increase in adult obesity rates has been accompanied by a increase in childhood obesity rates. In the past two decades, the obesity rate among children under 5 years of age has increased from 32 to 42 million. If childhood obesity is not intervened in the early years, it will continue into adulthood and remain there for life. Among the potential causative factors, early lifestyle may influence the composition of the gut flora in childhood obesity, such as the rate and intake of high-energy foods, low levels of physical activity, may persist into adulthood, thus, early lifestyle interventions may improve the composition of the gut flora in obese children. Adipose Axis plays an important role in the development of obesity. Adipose tissue is characterized by increased expression of nucleoside diphosphate-linked molecule X-type motif 2 (NUDT2), amphiphilic protein AMPH genes, which encode proteins that all play important roles in the CNS. NUDT2 is associated with intellectual disability. Furthermore, amphiphysin (AMPH) is involved in glutamatergic signaling, ganglionic synapse development, and maturation, which is associated with mild cognitive impairment (MCI) and Alzheimer's disease (AD). All of the above studies show that obesity is closely related to cognitive decline in patients. Animal experiments have confirmed that obesity causes changes in cognitive function. For example, high-fat diets rich in long- and medium-chain saturated fatty acids may adversely affect cognitive function in obese mice. This process may be attributed to the Short-Chain Fatty Acid (SCFA)-rich high-fat diet (HFD) activating enterocyte TLR signaling, especially TLR-2 and TLR-4, altering the downstream MyD88-4 signaling, thereby impacting the downstream MyD88-NF-κB signaling cascade and up-regulating the levels of pro-inflammatory factors and lipopolysaccharide (LPS). These changes result in the loss of integrity of the intestinal mucosa and cause an imbalance in the internal environment. Obesity may lead to the disruption of the intestinal flora and damage the intestinal barrier function, causing intestinal flora dysbiosis. In recent years, a growing number of studies have investigated the relationship between obesity and the intestinal flora. For example, high-fat and high-sugar diets have been found to lead to the thinning of the mucus layer of the colon, a decrease in the number of tight junction proteins, and an increase in intestinal permeability in mice. Such changes alter the composition of intestinal microorganisms, allow endotoxins into the blood circulation, and induce neuroinflammation and brain damage. Therefore, obesity affects cognitive function and is even hereditary. This paper reviews the obesity-induced cognitive dysfunction, the underlying mechanisms, the research progress of intestinal flora dysregulation in obese patients, the relationship between intestinal flora and cognitive function changes, and the research progress on intestinal flora dysregulation in obese patients. We want to regulate the internal environment of obese patients from the perspective of intestinal flora, improving the cognitive function of obese patients, and prevent obesity-induced changes in related neurological functions.

Exploring the global impact of obesity and diet on dementia burden: the role of national policies and sex differences

Obesity is a significant modifiable risk factor for dementia. This study aims to quantify the global impact of obesity on dementia burden and examine how national strategies for managing overweight/obesity and dietary factors influence dementia prevalence and mortality, with a focus on sex-specific differences. We used data from the Global Burden of Disease (GBD) and World Health Organization (WHO) to evaluate the association between obesity age-standardized prevalence rate (ASPR) and dementia age-standardized mortality rate (ASMR) and ASPR across 161 countries. A two-step multivariate analysis adjusted for socioeconomic and lifestyle factors was performed. Temporal trends in dementia were analyzed based on the presence of national obesity management strategies and varying dietary scores. A 1% increase in national obesity prevalence was associated with a 0.36% increase in dementia mortality (OR: 1.0036; 95% CI: 1.0028-1.0045) in males and 0.12% in females (OR: 1.0012; 95% CI: 1.0007-1.0018). A 1% increase in national obesity ASPR was associated with an increase in ASPR of dementia by 0.26% for males (OR: 1.0026, 95% CI: 1.0024-1.0028) and 0.05% for females (OR: 1.0005, 95% CI: 1.0004-1.0006). Males exhibited a higher susceptibility to obesity-related dementia. Countries with national obesity management strategies showed a significantly greater reduction in dementia mortality, particularly among females (P = 0.025). Higher dietary scores were associated with a more significant decrease in dementia prevalence across both sexes. Rising obesity prevalence is linked to increased dementia burden globally, with males being more vulnerable to this relationship. National management of overweight/obesity and healthier dietary habits may help mitigate the dementia burden, emphasizing the need for integrated public health interventions.

Cerebromicrovascular mechanisms contributing to long COVID: implications for neurocognitive health

Long COVID (also known as post-acute sequelae of SARS-CoV-2 infection [PASC] or post-COVID syndrome) is characterized by persistent symptoms that extend beyond the acute phase of SARS-CoV-2 infection, affecting approximately 10% to over 30% of those infected. It presents a significant clinical challenge, notably due to pronounced neurocognitive symptoms such as brain fog. The mechanisms underlying these effects are multifactorial, with mounting evidence pointing to a central role of cerebromicrovascular dysfunction. This review investigates key pathophysiological mechanisms contributing to cerebrovascular dysfunction in long COVID and their impacts on brain health. We discuss how endothelial tropism of SARS-CoV-2 and direct vascular infection trigger endothelial dysfunction, impaired neurovascular coupling, and blood-brain barrier disruption, resulting in compromised cerebral perfusion. Furthermore, the infection appears to induce mitochondrial dysfunction, enhancing oxidative stress and inflammation within cerebral endothelial cells. Autoantibody formation following infection also potentially exacerbates neurovascular injury, contributing to chronic vascular inflammation and ongoing blood-brain barrier compromise. These factors collectively contribute to the emergence of white matter hyperintensities, promote amyloid pathology, and may accelerate neurodegenerative processes, including Alzheimer's disease. This review also emphasizes the critical role of advanced imaging techniques in assessing cerebromicrovascular health and the need for targeted interventions to address these cerebrovascular complications. A deeper understanding of the cerebrovascular mechanisms of long COVID is essential to advance targeted treatments and mitigate its long-term neurocognitive consequences.

Endothelial Colony-Forming Cells (ECFCs) in cerebrovascular aging: Focus on the pathogenesis of Vascular Cognitive Impairment and Dementia (VCID), and treatment prospects

Endothelial colony-forming cells (ECFCs), a unique endothelial progenitor subset, are essential for vascular integrity and repair, providing significant regenerative potential. Recent studies highlight their role in cerebrovascular aging, particularly in the pathogenesis of vascular cognitive impairment and dementia (VCID). Aging disrupts ECFC functionality through mechanisms such as oxidative stress, chronic inflammation, and cellular senescence, leading to compromised vascular repair and reduced neurovascular resilience. ECFCs influence key cerebrovascular processes, including neurovascular coupling (NVC), blood-brain barrier (BBB) integrity, and vascular regeneration, which are critical for cognitive health. Age-related decline in ECFC quantity and functionality contributes to vascular rarefaction, diminished cerebral blood flow (CBF), and BBB permeability-processes that collectively exacerbate cognitive decline. This review delves into the multifaceted role of ECFCs in cerebrovascular aging and underscores their potential as therapeutic targets in addressing age-related vascular dysfunctions, presenting new directions for mitigating the effects of aging on brain health.

Dietary flaxseed: Cardiometabolic benefits and its role in promoting healthy aging

Flaxseed, a rich source of omega-3 polyunsaturated fatty acid alpha-linolenic acid (ALA), lignans, and soluble fiber, has attracted attention for its potential to improve multiple cardiometabolic risk factors. While its benefits are well-recognized, comprehensive evaluations of its direct impact on clinical outcomes, such as the prevention or progression of cardiometabolic diseases, remain limited. Additionally, its potential to support healthy aging and longevity through fundamental biological mechanisms has not been fully elucidated. This review synthesizes existing research on flaxseed supplementation, highlighting its effects on cardiometabolic risk factors and outcomes, the underlying biological mechanisms, and its broader implications for health promotion and aging. Findings demonstrate that flaxseed supplementation significantly improves several cardiometabolic risk factors, including body weight, body mass index, lipid levels, blood pressure, glycemic measures, markers of inflammation (e.g., C-reactive protein and interleukin-6), oxidative stress, and liver enzymes. Blood pressure reductions range from approximately 2 to 15 mmHg for systolic blood pressure and 1 to 7 mmHg for diastolic blood pressure, with the magnitude influenced by dose, duration, and baseline risk profiles. While direct evidence linking flaxseed to the prevention of hypertension, metabolic syndrome, metabolic dysfunction-associated steatotic liver disease, type 2 diabetes, chronic kidney disease, and cardiovascular disease is limited, its bioactive components-ALA, lignans, and fiber-are strongly associated with reduced risks of these conditions. The benefits of flaxseed are mediated through multiple pathways, including anti-inflammatory and antioxidant effects, improved lipid levels, improved glucose metabolism and insulin sensitivity, modulation of gut microbiota, and enhanced vascular health. Beyond cardiometabolic outcomes, flaxseed may influence key biological processes relevant to aging, underscoring its potential to promote healthy aging and longevity. Optimal cardiometabolic benefits appear to be achieved with ground whole flaxseed at doses of ≥ 30 g/day for at least 12 weeks, particularly among individuals at high cardiometabolic risk. Future research should focus on elucidating flaxseed's mechanisms of action, clarifying its role in disease prevention, and refining dietary recommendations to harness its potential for cardiometabolic health and aging interventions.

A multifactorial lens on risk factors promoting the progression of Alzheimer's disease

The prevalence of Alzheimer's disease (AD) among adults has continued to increase over the last two decades, which has sparked a significant increase in research that focuses on the topic of "brain health." While AD is partially determined by a genetic predisposition, there are still numerous pathophysiological factors that require further research. This research requirement stems from the acknowledgment that AD is a multifactorial disease that to date, cannot be prevented. Therefore, addressing and understanding the potential AD risk factors is necessary to increase the quality of life of an aging population. To raise awareness of critical pathways that impact AD progression, this review manuscript describes AD etiologies, structural impairments, and biomolecular changes that can significantly increase the risk of AD. Among them, a special highlight is given to inflammasomes, which have been shown to bolster neuroinflammation. Alike, the role of brain-derived neurotrophic factor, an essential neuropeptide that promotes the preservation of cognition is presented. In addition, the functional role of neurovascular units to regulate brain health is highlighted and contrasted to inflammatory conditions, such as cellular senescence, vascular damage, and increased visceral adiposity, who all increase the risk of neuroinflammation. Altogether, a multifactorial interventional approach is warranted to reduce the risk of AD.

Pharmacological inactivation of a non-canonical gp130 signaling arm attenuates chronic systemic inflammation and multimorbidity induced by a high-fat diet

Interleukin-6 (IL-6) is a major pro-inflammatory cytokine that demonstrates a robust correlation with age and body mass index (BMI) as part of the senescence-associated secretory phenotype. IL-6 cytokines also play a crucial role in metabolic homeostasis and regenerative processes primarily via the canonical STAT3 pathway. Thus, selective modulation of IL-6 signaling may offer a unique opportunity for therapeutic interventions. Our recent studies identified a novel non-canonical signaling pathway that involves prolonged activation of SRC family of kinases (SFKs) by IL-6/gp130, where genetic or pharmacological inhibition of this pathway was protective in several acute injury models. This study was designed to assess the effect of a small molecule (R159) that inhibits the non-canonical signaling in a mouse model of multimorbidity induced by chronic inflammation. Aged mice were fed a high-fat diet (HFD) to exacerbate chronic inflammation and inflammaging-related conditions, and R159 significantly decreased systemic inflammatory responses in adipose tissue and liver. R159 was protective against trabecular bone and articular cartilage loss and markedly prevented neurogenesis decline. Moreover, R159 reduced weight gain induced by HFD and increased physical activity levels. These findings suggest that selective pharmacological inhibition of SFK signaling downstream of IL6/gp130 offers a promising strategy to alleviate systemic chronic inflammation and relevant multimorbidity.

Coffee consumption and cardiometabolic health: a comprehensive review of the evidence

This review provides a comprehensive synthesis of longitudinal observational and interventional studies on the cardiometabolic effects of coffee consumption. It explores biological mechanisms, and clinical and policy implications, and highlights gaps in the evidence while suggesting future research directions. It also reviews evidence on the causal relationships between coffee consumption and cardiometabolic outcomes from Mendelian randomization (MR) studies. Findings indicate that while coffee may cause short-term increases in blood pressure, it does not contribute to long-term hypertension risk. There is limited evidence indicating that coffee intake might reduce the risk of metabolic syndrome and non-alcoholic fatty liver disease. Furthermore, coffee consumption is consistently linked with reduced risks of type 2 diabetes (T2D) and chronic kidney disease (CKD), showing dose-response relationships. The relationship between coffee and cardiovascular disease is complex, showing potential stroke prevention benefits but ambiguous effects on coronary heart disease. Moderate coffee consumption, typically ranging from 1 to 5 cups per day, is linked to a reduced risk of heart failure, while its impact on atrial fibrillation remains inconclusive. Furthermore, coffee consumption is associated with a lower risk of all-cause mortality, following a U-shaped pattern, with the largest risk reduction observed at moderate consumption levels. Except for T2D and CKD, MR studies do not robustly support a causal link between coffee consumption and adverse cardiometabolic outcomes. The potential beneficial effects of coffee on cardiometabolic health are consistent across age, sex, geographical regions, and coffee subtypes and are multi-dimensional, involving antioxidative, anti-inflammatory, lipid-modulating, insulin-sensitizing, and thermogenic effects. Based on its beneficial effects on cardiometabolic health and fundamental biological processes involved in aging, moderate coffee consumption has the potential to contribute to extending the healthspan and increasing longevity. The findings underscore the need for future research to understand the underlying mechanisms and refine health recommendations regarding coffee consumption.

Therapeutic effects of alpha lipoic acid and/or caffeine-loaded chitosan nanoparticles on memory impairment and neurochemical changes in high-fat diet-induced obese rats

The therapeutic effects of alpha lipoic acid (LA) and/or caffeine-loaded chitosan nanoparticles (CCNPs) on obesity-induced memory impairment were evaluated in the present study. Rats were divided into control rats, obese rats induced by high fat diet (HFD) and obese rats treated with LA and/or CCNPs. Obesity was confirmed by measuring the body mass index (BMI). Memory and cognitive functions were evaluated by novel object recognition test (NORT). The levels of serotonin (5-HT), dopamine (DA), norepinephrine (NE), lipid peroxidation (MDA), nitric oxide (NO), reduced glutathione (GSH), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), leptin (LEP) and ghrelin (GHR) and the activities of monoamine oxidase (MAO), acetylcholinesterase (AchE) and Na+,K+,ATPase were determined in the cortex and hippocampus. The cerebral histopathological alterations were examined in obese rats. Obese rats showed impaired memory and exhibited significant neurochemical changes, including decreased levels of 5-HT, DA, GSH, GHR, and Na+,K+-ATPase activity, as well as an increase in AchE, MAO, MDA, NO, IL-1β, TNF-α, and LEP. LA and/or CCNPs treatment reduced BMI and improved memory. LA or CCNPs alleviated the cortical and hippocampal neurochemical changes and histopathological changes induced by obesity. Furthermore, LA and CCNPs exhibited antioxidant and anti-inflammatory properties, which likely contributed to their effects. However, no synergistic effect was observed between LA and CCNPs. These findings suggest that LA or CCNPs may be a potential therapy against obesity and its adverse effects on memory, mediated by their ability to restore monoamine levels and exhibit antioxidant and anti-inflammatory properties.

Linking peripheral atherosclerosis to blood-brain barrier disruption: elucidating its role as a manifestation of cerebral small vessel disease in vascular cognitive impairment

Aging plays a pivotal role in the pathogenesis of cerebral small vessel disease (CSVD), contributing to the onset and progression of vascular cognitive impairment and dementia (VCID). In older adults, CSVD often leads to significant pathological outcomes, including blood-brain barrier (BBB) disruption, which in turn triggers neuroinflammation and white matter damage. This damage is frequently observed as white matter hyperintensities (WMHs) in neuroimaging studies. There is mounting evidence that older adults with atherosclerotic vascular diseases, such as peripheral artery disease, ischemic heart disease, and carotid artery stenosis, face a heightened risk of developing CSVD and VCID. This review explores the complex relationship between peripheral atherosclerosis, the pathogenesis of CSVD, and BBB disruption. It explores the continuum of vascular aging, emphasizing the shared pathomechanisms that underlie atherosclerosis in large arteries and BBB disruption in the cerebral microcirculation, exacerbating both CSVD and VCID. By reviewing current evidence, this paper discusses the impact of endothelial dysfunction, cellular senescence, inflammation, and oxidative stress on vascular and neurovascular health. This review aims to enhance understanding of these complex interactions and advocate for integrated approaches to manage vascular health, thereby mitigating the risk and progression of CSVD and VCID.

Supramolecular approach to the design of nanocarriers for antidiabetic drugs: targeted patient-friendly therapy

Diabetes and its complications derived are among serious global health concerns that critically deteriorate the quality of life of patients and, in some cases, result in lethal outcome. Herein, general information on the pathogenesis, factors aggravating the course of the disease and drugs used for the treatment of two types of diabetes are briefly discussed. The aim of the review is to introduce supramolecular strategies that are currently being developed for the treatment of diabetes mellitus and that present a very effective alternative to chemical synthesis, allowing the fabrication of nanocontainers with switchable characteristics that meet the criteria of green chemistry. Particular attention is paid to organic (amphiphilic and polymeric) formulations, including those of natural origin, due to their biocompatibility, low toxicity, and bioavailability. The advantages and limitations of different nanosystems are discussed, with emphasis on their adaptivity to noninvasive administration routes.<br>The bibliography includes 378 references.

Single Nuclei Transcriptomics Reveals Obesity-Induced Endothelial and Neurovascular Dysfunction: Implications for Cognitive Decline

Obesity confers risk for cardiovascular disease and vascular dementia. However, genomic alterations modulated by obesity in endothelial cells in the brain and their relationship to other neurovascular unit (NVU) cells are unknown. We performed single nuclei RNA sequencing (snRNAseq) of the NVU (endothelial cells, astrocytes, microglia, and neurons) from the hippocampus of obese (ob/ob) and wild-type (WT) male mice to characterize obesity-induced transcriptomic changes in a key brain memory center and assessed blood-brain barrier permeability (BBB) by gadolinium-enhanced magnetic resonance imaging (MRI). Ob/ob mice displayed obesity, hyperinsulinemia, and impaired glucose tolerance. snRNAseq profiled 14 distinct cell types and 32 clusters within the hippocampus of ob/ob and WT mice and uncovered differentially expressed genes (DEGs) in all NVU cell types, namely, 4462 in neurons, 1386 in astrocytes, 125 in endothelial cells, and 154 in microglia. Gene ontology analysis identified important biological processes such as angiogenesis in endothelial cells and synaptic trafficking in neurons. Cellular pathway analysis included focal adhesion and insulin signaling, which were common to all NVU cell types. Correlation analysis revealed significant positive correlations between endothelial cells and other NVU cell types. Differentially expressed long non-coding RNAs (lncRNAs) were observed in cells of the NVU-affecting pathways such as TNF and mTOR. BBB permeability showed a trend toward increased signal intensity in ob/ob mice. Taken together, our study provides in-depth insight into the molecular mechanisms underlying cognitive dysfunction in obesity and may have implications for therapeutic gene targeting.

Overweight and obesity significantly increase colorectal cancer risk: a meta-analysis of 66 studies revealing a 25-57% elevation in risk

The incidence of colorectal cancer (CRC) has been steadily rising, and obesity has been identified as a significant risk factor. Numerous studies suggest a strong correlation between excess body weight and increased risk of CRC, but comprehensive quantification through pooled analysis remains limited. This study aims to systematically review and meta-analyze the existing literature to evaluate the association between obesity and CRC risk, considering variations across sex and study designs. A systematic literature search was conducted in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science to identify randomized controlled trials and human clinical trials from 1992 to 2024. Statistical analysis was performed using the https://metaanalysisonline.com web application using a random effects model to estimate the pooled hazard rates (HR). Forest plots, funnel plots, and Z-score plots were utilized to visualize results. We identified 52 clinical trials and 14 case-control studies, encompassing a total of 83,251,050 and 236,877 subjects, respectively. The pooled analysis indicated that obesity significantly increased the prevalence of CRC (HR = 1.36, 95% CI = 1.24-1.48, p < 0.01). This effect was consistent across sexes, with HRs of 1.57 (95% CI = 1.38-1.78, p = 0.01) for males and 1.25 (95% CI = 1.14-1.38, p < 0.01) for females. Case-control studies specifically showed an effect, but with marginal significance only (HR = 1.27, 95% CI = 0.98-1.65, p = 0.07). The Z-score plot indicated the need for additional analysis in the case-control group. A significant heterogeneity was observed across studies in all four settings. This meta-analysis provides robust evidence that obesity is a significant risk factor for colorectal cancer, with an overall hazard rate indicating a 36% increased risk. The effect is pronounced across both sexes, with males showing a slightly higher risk compared to females. Although case-control studies showed a weaker association, the overall trend supports the link between obesity and CRC. These results underscore the importance of public health interventions aimed at reducing obesity to potentially lower the risk of colorectal cancer.

Role of the gut microbiome in mediating sex-specific differences in the pathophysiology of Alzheimer's disease

Alzheimer's disease (AD) presents distinct pathophysiological features influenced by biological sex, with women disproportionately affected due to sex-specific genetic, hormonal, and epigenetic factors. This review delves into three critical areas of sex differences in AD: First, we explore how genetic predisposition and hormonal changes, particularly those involving sex-specific modifications, influence susceptibility and progression of the disease. Second, we examine the neuroimmune dynamics in AD, emphasizing variations in microglial activity between sexes during crucial developmental stages and the effects of hormonal interventions on disease outcomes. Crucially, this review highlights the significant role of gut microbiome perturbations in shaping AD pathophysiology in a sex-specific manner, suggesting that these alterations can further influence microglial activity and overall disease trajectory. Third, we provide a viewpoint that advocates for personalized therapeutic strategies that integrate the understanding of hormonal fluctuations and microbiome dynamics into treatment plans in order to optimize patient outcomes.

Atherosclerotic burden and cerebral small vessel disease: exploring the link through microvascular aging and cerebral microhemorrhages

Cerebral microhemorrhages (CMHs, also known as cerebral microbleeds) are a critical but frequently underestimated aspect of cerebral small vessel disease (CSVD), bearing substantial clinical consequences. Detectable through sensitive neuroimaging techniques, CMHs reveal an extensive pathological landscape. They are prevalent in the aging population, with multiple CMHs often being observed in a given individual. CMHs are closely associated with accelerated cognitive decline and are increasingly recognized as key contributors to the pathogenesis of vascular cognitive impairment and dementia (VCID) and Alzheimer's disease (AD). This review paper delves into the hypothesis that atherosclerosis, a prevalent age-related large vessel disease, extends its pathological influence into the cerebral microcirculation, thereby contributing to the development and progression of CSVD, with a specific focus on CMHs. We explore the concept of vascular aging as a continuum, bridging macrovascular pathologies like atherosclerosis with microvascular abnormalities characteristic of CSVD. We posit that the same risk factors precipitating accelerated aging in large vessels (i.e., atherogenesis), primarily through oxidative stress and inflammatory pathways, similarly instigate accelerated microvascular aging. Accelerated microvascular aging leads to increased microvascular fragility, which in turn predisposes to the formation of CMHs. The presence of hypertension and amyloid pathology further intensifies this process. We comprehensively overview the current body of evidence supporting this interconnected vascular hypothesis. Our review includes an examination of epidemiological data, which provides insights into the prevalence and impact of CMHs in the context of atherosclerosis and CSVD. Furthermore, we explore the shared mechanisms between large vessel aging, atherogenesis, microvascular aging, and CSVD, particularly focusing on how these intertwined processes contribute to the genesis of CMHs. By highlighting the role of vascular aging in the pathophysiology of CMHs, this review seeks to enhance the understanding of CSVD and its links to systemic vascular disorders. Our aim is to provide insights that could inform future therapeutic approaches and research directions in the realm of neurovascular health.

Young blood-mediated cerebromicrovascular rejuvenation through heterochronic parabiosis: enhancing blood-brain barrier integrity and capillarization in the aged mouse brain

Age-related cerebromicrovascular changes, including blood-brain barrier (BBB) disruption and microvascular rarefaction, play a significant role in the development of vascular cognitive impairment (VCI) and neurodegenerative diseases. Utilizing the unique model of heterochronic parabiosis, which involves surgically joining young and old animals, we investigated the influence of systemic factors on these vascular changes. Our study employed heterochronic parabiosis to explore the effects of young and aged systemic environments on cerebromicrovascular aging in mice. We evaluated microvascular density and BBB integrity in parabiotic pairs equipped with chronic cranial windows, using intravital two-photon imaging techniques. Our results indicate that short-term exposure to young systemic factors leads to both functional and structural rejuvenation of cerebral microcirculation. Notably, we observed a marked decrease in capillary density and an increase in BBB permeability to fluorescent tracers in the cortices of aged mice undergoing isochronic parabiosis (20-month-old C57BL/6 mice [A-(A)]; 6 weeks of parabiosis), compared to young isochronic parabionts (6-month-old, [Y-(Y)]). However, aged heterochronic parabionts (A-(Y)) exposed to young blood exhibited a significant increase in cortical capillary density and restoration of BBB integrity. In contrast, young mice exposed to old blood from aged parabionts (Y-(A)) rapidly developed cerebromicrovascular aging traits, evidenced by reduced capillary density and increased BBB permeability. These findings underscore the profound impact of systemic factors in regulating cerebromicrovascular aging. The rejuvenation observed in the endothelium, following exposure to young blood, suggests the existence of anti-geronic elements that counteract microvascular aging. Conversely, pro-geronic factors in aged blood appear to accelerate cerebromicrovascular aging. Further research is needed to assess whether the rejuvenating effects of young blood factors could extend to other age-related cerebromicrovascular pathologies, such as microvascular amyloid deposition and increased microvascular fragility.

Neural ageing and synaptic plasticity: prioritizing brain health in healthy longevity

Ageing is characterized by a gradual decline in the efficiency of physiological functions and increased vulnerability to diseases. Ageing affects the entire body, including physical, mental, and social well-being, but its impact on the brain and cognition can have a particularly significant effect on an individual's overall quality of life. Therefore, enhancing lifespan and physical health in longevity studies will be incomplete if cognitive ageing is over looked. Promoting successful cognitive ageing encompasses the objectives of mitigating cognitive decline, as well as simultaneously enhancing brain function and cognitive reserve. Studies in both humans and animal models indicate that cognitive decline related to normal ageing and age-associated brain disorders are more likely linked to changes in synaptic connections that form the basis of learning and memory. This activity-dependent synaptic plasticity reorganises the structure and function of neurons not only to adapt to new environments, but also to remain robust and stable over time. Therefore, understanding the neural mechanisms that are responsible for age-related cognitive decline becomes increasingly important. In this review, we explore the multifaceted aspects of healthy brain ageing with emphasis on synaptic plasticity, its adaptive mechanisms and the various factors affecting the decline in cognitive functions during ageing. We will also explore the dynamic brain and neuroplasticity, and the role of lifestyle in shaping neuronal plasticity.

Peripheral inflammation is associated with brain atrophy and cognitive decline linked to mild cognitive impairment and Alzheimer's disease

Inflammation is an important factor in Alzheimer's disease (AD). An NMR measurement in plasma, glycoprotein acetyls (GlycA), captures the overall level of protein production and glycosylation implicated in systemic inflammation. With its additional advantage of reducing biological variability, GlycA might be useful in monitoring the relationship between peripheral inflammation and brain changes relevant to AD. However, the associations between GlycA and these brain changes have not been fully evaluated. Here, we performed Spearman's correlation analyses to evaluate these associations cross-sectionally and determined whether GlycA can inform AD-relevant longitudinal measurements among participants in the Alzheimer's Disease Neuroimaging Initiative (n = 1506), with additional linear models and stratification analyses to evaluate the influences of sex or diagnosis status and confirm findings from Spearman's correlation analyses. We found that GlycA was elevated in AD patients compared to cognitively normal participants. GlycA correlated negatively with multiple concurrent regional brain volumes in females diagnosed with late mild cognitive impairment (LMCI) or AD. Baseline GlycA level was associated with executive function decline at 3-9 year follow-up in participants diagnosed with LMCI at baseline, with similar but not identical trends observed in the future decline of memory and entorhinal cortex volume. Results here indicated that GlycA is an inflammatory biomarker relevant to AD pathogenesis and that the stage of LMCI might be relevant to inflammation-related intervention.

Cellular Components of the Blood-Brain Barrier and Their Involvement in Aging-Associated Cognitive Impairment

Human life expectancy has been significantly extended, which poses major challenges to our healthcare and social systems. Aging-associated cognitive impairment is attributed to endothelial dysfunction in the cardiovascular system and neurological dysfunction in the central nervous system. The central nervous system is considered an immune-privileged tissue due to the exquisite protection provided by the blood-brain barrier. The present review provides an overview of the structure and function of blood-brain barrier, extending the cell components of blood-brain barrier from endothelial cells and pericytes to astrocytes, perivascular macrophages and oligodendrocyte progenitor cells. In particular, the pathological changes in the blood-brain barrier in aging, with special focus on the underlying mechanisms and molecular changes, are presented. Furthermore, the potential preventive/therapeutic strategies against aging-associated blood-brain barrier disruption are discussed.

Chronic β3 adrenergic agonist treatment improves brain microvascular endothelial function and cognition in aged mice

Microvascular endothelial dysfunction, characterized by impaired neurovascular coupling, reduced glucose uptake, blood-brain barrier disruption, and microvascular rarefaction, plays a critical role in the pathogenesis of age-related vascular cognitive impairment (VCI). Emerging evidence points to non-cell autonomous mechanisms mediated by adverse circulating milieu (an increased ratio of pro-geronic to anti-geronic circulating factors) in the pathogenesis of endothelial dysfunction leading to impaired cerebral blood flow and cognitive decline in the aging population. In particular, age-related adipose dysfunction contributes, at least in part, to an unfavorable systemic milieu characterized by chronic hyperglycemia, hyperinsulinemia, dyslipidemia, and altered adipokine profile, which together contribute to microvascular endothelial dysfunction. Hence, in the present study, we aimed to test whether thermogenic stimulation, an intervention known to improve adipose and systemic metabolism by increasing cellular energy expenditure, could mitigate brain endothelial dysfunction and improve cognition in the aging population. Eighteen-month-old old C57BL/6J mice were treated with saline or CL (β3-adrenergic agonist) for 6 weeks followed by functional analysis to assess endothelial function and cognition. CL treatment improved neurovascular coupling responses and rescued brain glucose uptake in aged animals. In addition, CL treatment also attenuated blood-brain barrier leakage and associated neuroinflammation in the cortex of aged animals. More importantly, these beneficial changes in microvascular function translated to improved cognitive performance in radial arm water maze and Y-maze tests. Our results suggest that β3-adrenergic agonist treatment improves multiple aspects of brain microvascular endothelial function and can be potentially repurposed for treating age-associated cognitive decline.

Excision of the endothelial blood-brain barrier insulin receptor does not alter spatial cognition in mice fed either a chow or high-fat diet

Insulin is transported across the blood-brain barrier (BBB) endothelium to regulate aspects of metabolism and cognition. Brain insulin resistance often results from high-fat diet (HFD) consumption and is thought to contribute to spatial cognition deficits. To target BBB insulin function, we used Cre-LoxP genetic excision of the insulin receptor (InsR) from endothelial cells in adult male mice. We hypothesized that this excision would impair spatial cognition, and that high-fat diet consumption would exacerbate these effects. Excision of the endothelial InsR did not impair performance in two spatial cognition tasks, the Y-Maze and Morris Water Maze, in tests held both before and after 14 weeks of access to high-fat (or chow control) diet. The HFD increased body weight gain and induced glucose intolerance but did not impair spatial cognition. Endothelial InsR excision tended to increase body weight and reduce sensitivity to peripheral insulin, but these metabolic effects were not associated with impairments to spatial cognition and did not interact with HFD exposure. Instead, all mice showed intact spatial cognitive performance regardless of whether they had been fed chow or a HFD, and whether the InsR had been excised or not. Overall, the results indicate that loss of the endothelial InsR does not impact spatial cognition, which is in line with pharmacological evidence that other mechanisms at the BBB facilitate insulin transport and allow it to exert its pro-cognitive effects.

Air pollution accelerates the development of obesity and Alzheimer's disease: the role of leptin and inflammation - a mini-review

Air pollution is an urgent concern linked to numerous health problems in low- and middle-income countries, where 92% of air pollution-related deaths occur. Particulate matter 2.5 (PM2.5) is the most harmful component of air pollutants, increasing inflammation and changing gut microbiota, favoring obesity, type 2 diabetes, and Alzheimer's Disease (AD). PM2.5 contains lipopolysaccharides (LPS), which can activate the Toll-like receptor 4 (TLR4) signaling pathway. This pathway can lead to the release of pro-inflammatory markers, including interleukins, and suppressor of cytokine signaling-3 (SOCS3), which inhibits leptin action, a hormone that keeps the energy homeostasis. Leptin plays a role in preventing amyloid plaque deposition and hyperphosphorylation of tau-protein (p-tau), mechanisms involved in the neurodegeneration in AD. Approximately 50 million people worldwide are affected by dementia, with a significant proportion living in low-and middle-income countries. This number is expected to triple by 2050. This mini-review focuses on the potential impact of PM2.5 exposure on the TLR4 signaling pathway, its contribution to leptin resistance, and dysbiosis that exacerbates the link between obesity and AD.

Mechanistic correlation of molecular pathways in obesity-mediated stroke pathogenesis

Obesity, a prominent risk factor for the development of heart attacks and several cardiovascular ailments. Obesity ranks as the second most significant avoidable contributor to mortality, whereas stroke stands as the second leading cause of death on a global scale. While changes in lifestyle have been demonstrated to have significant impacts on weight management, the long-term weight loss remains challenging, and the global prevalence of obesity continues to rise. The pathophysiology of obesity has been extensively studied during the last few decades, and an increasing number of signal transduction pathways have been linked to obesity preclinically. This review is focused on signaling pathways, and their respective functions in regulating the consumption of fatty food as well as accumulation of adipose tissue, and the resulting morphological and cognitive changes in the brain of individuals with obesity. We have also emphasized the recent progress in the mechanisms behind the emergence of obesity, as elucidated by both experimental and clinical investigations. The mounting understanding of signaling transduction may shed light on the future course of obesity research as we move into a new era of precision medicine.

Obesity during preclinical Alzheimer's disease development exacerbates brain metabolic decline

Alzheimer's disease (AD) is the most common form of dementia. Obesity in middle age increases AD risk and severity, which is alarming given that obesity prevalence peaks at middle age and obesity rates are accelerating worldwide. Midlife, but not late-life obesity increases AD risk, suggesting that this interaction is specific to preclinical AD. AD pathology begins in middle age, with accumulation of amyloid beta (Aβ), hyperphosphorylated tau, metabolic decline, and neuroinflammation occurring decades before cognitive symptoms appear. We used a transcriptomic discovery approach in young adult (6.5 months old) male and female TgF344-AD rats that overexpress mutant human amyloid precursor protein and presenilin-1 and wild-type (WT) controls to determine whether inducing obesity with a high-fat/high-sugar "Western" diet during preclinical AD increases brain metabolic dysfunction in dorsal hippocampus (dHC), a brain region vulnerable to the effects of obesity and early AD. Analyses of dHC gene expression data showed dysregulated mitochondrial and neurotransmission pathways, and up-regulated genes involved in cholesterol synthesis. Western diet amplified the number of genes that were different between AD and WT rats and added pathways involved in noradrenergic signaling, dysregulated inhibition of cholesterol synthesis, and decreased intracellular lipid transporters. Importantly, the Western diet impaired dHC-dependent spatial working memory in AD but not WT rats, confirming that the dietary intervention accelerated cognitive decline. To examine later consequences of early transcriptional dysregulation, we measured dHC monoamine levels in older (13 months old) AD and WT rats of both sexes after long-term chow or Western diet consumption. Norepinephrine (NE) abundance was significantly decreased in AD rats, NE turnover was increased, and the Western diet attenuated the AD-induced increases in turnover. Collectively, these findings indicate obesity during prodromal AD impairs memory, potentiates AD-induced metabolic decline likely leading to an overproduction of cholesterol, and interferes with compensatory increases in NE transmission.

Accelerated Aging Induced by an Unhealthy High-Fat Diet: Initial Evidence for the Role of Nrf2 Deficiency and Impaired Stress Resilience in Cellular Senescence

High-fat diets (HFDs) have pervaded modern dietary habits, characterized by their excessive saturated fat content and low nutritional value. Epidemiological studies have compellingly linked HFD consumption to obesity and the development of type 2 diabetes mellitus. Moreover, the synergistic interplay of HFD, obesity, and diabetes expedites the aging process and prematurely fosters age-related diseases. However, the underlying mechanisms driving these associations remain enigmatic. One of the most conspicuous hallmarks of aging is the accumulation of highly inflammatory senescent cells, with mounting evidence implicating increased cellular senescence in the pathogenesis of age-related diseases. Our hypothesis posits that HFD consumption amplifies senescence burden across multiple organs. To scrutinize this hypothesis, we subjected mice to a 6-month HFD regimen, assessing senescence biomarker expression in the liver, white adipose tissue, and the brain. Aging is intrinsically linked to impaired cellular stress resilience, driven by dysfunction in Nrf2-mediated cytoprotective pathways that safeguard cells against oxidative stress-induced senescence. To ascertain whether Nrf2-mediated pathways shield against senescence induction in response to HFD consumption, we explored senescence burden in a novel model of aging: Nrf2-deficient (Nrf2+/-) mice, emulating the aging phenotype. Our initial findings unveiled significant Nrf2 dysfunction in Nrf2+/- mice, mirroring aging-related alterations. HFD led to substantial obesity, hyperglycemia, and impaired insulin sensitivity in both Nrf2+/- and Nrf2+/+ mice. In control mice, HFD primarily heightened senescence burden in white adipose tissue, evidenced by increased Cdkn2a senescence biomarker expression. In Nrf2+/- mice, HFD elicited a significant surge in senescence burden across the liver, white adipose tissue, and the brain. We postulate that HFD-induced augmentation of senescence burden may be a pivotal contributor to accelerated organismal aging and the premature onset of age-related diseases.

A latent clinical-anatomical dimension relating metabolic syndrome to brain structure and cognition

The link between metabolic syndrome (MetS) and neurodegenerative as well as cerebrovascular conditions holds substantial implications for brain health in at-risk populations. This study elucidates the complex relationship between MetS and brain health by conducting a comprehensive examination of cardiometabolic risk factors, brain morphology, and cognitive function in 40,087 individuals. Multivariate, data-driven statistics identified a latent dimension linking more severe MetS to widespread brain morphological abnormalities, accounting for up to 71% of shared variance in the data. This dimension was replicable across sub-samples. In a mediation analysis, we could demonstrate that MetS-related brain morphological abnormalities mediated the link between MetS severity and cognitive performance in multiple domains. Employing imaging transcriptomics and connectomics, our results also suggest that MetS-related morphological abnormalities are linked to the regional cellular composition and macroscopic brain network organization. By leveraging extensive, multi-domain data combined with a dimensional stratification approach, our analysis provides profound insights into the association of MetS and brain health. These findings can inform effective therapeutic and risk mitigation strategies aimed at maintaining brain integrity.

PET imaging of synaptic density in Parkinsonian disorders

Synaptic dysfunction and altered synaptic pruning are present in people with Parkinsonian disorders. Dopamine loss and alpha-synuclein accumulation, two hallmarks of Parkinson's disease (PD) pathology, contribute to synaptic dysfunction and reduced synaptic density in PD. Atypical Parkinsonian disorders are likely to have unique spatiotemporal patterns of synaptic density, differentiating them from PD. Therefore, quantification of synaptic density has the potential to support diagnoses, monitor disease progression, and treatment efficacy. Novel radiotracers for positron emission tomography which target the presynaptic vesicle protein SV2A have been developed to quantify presynaptic density. The radiotracers have successfully investigated synaptic density in preclinical models of PD and people with Parkinsonian disorders. Therefore, this review will summarize the preclinical and clinical utilization of SV2A radiotracers in people with Parkinsonian disorders. We will evaluate how SV2A abundance is associated with other imaging modalities and the considerations for interpreting SV2A in Parkinsonian pathology.

Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction

The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.

The Semmelweis Study: a longitudinal occupational cohort study within the framework of the Semmelweis Caring University Model Program for supporting healthy aging

The Semmelweis Study is a prospective occupational cohort study that seeks to enroll all employees of Semmelweis University (Budapest, Hungary) aged 25 years and older, with a population of 8866 people, 70.5% of whom are women. The study builds on the successful experiences of the Whitehall II study and aims to investigate the complex relationships between lifestyle, environmental, and occupational risk factors, and the development and progression of chronic age-associated diseases. An important goal of the Semmelweis Study is to identify groups of people who are aging unsuccessfully and therefore have an increased risk of developing age-associated diseases. To achieve this, the study takes a multidisciplinary approach, collecting economic, social, psychological, cognitive, health, and biological data. The Semmelweis Study comprises a baseline data collection with open healthcare data linkage, followed by repeated data collection waves every 5 years. Data are collected through computer-assisted self-completed questionnaires, followed by a physical health examination, physiological measurements, and the assessment of biomarkers. This article provides a comprehensive overview of the Semmelweis Study, including its origin, context, objectives, design, relevance, and expected contributions.

Fibrinogen in mice cerebral microvessels induces blood-brain barrier dysregulation with aging via a dynamin-related protein 1-dependent pathway

We previously reported evidence that oxidative stress during aging leads to adverse protein profile changes of brain cortical microvessels (MVs: end arterioles, capillaries, and venules) that affect mRNA/protein stability, basement membrane integrity, and ATP synthesis capacity in mice. As an extension of our previous study, we also found that proteins which comprise the blood-brain barrier (BBB) and regulate mitochondrial quality control were also significantly decreased in the mice's cortical MVs with aging. Interestingly, the neuroinflammatory protein fibrinogen (Fgn) was increased in mice brain MVs, which corresponds with clinical reports indicating that the plasma Fgn concentration increased progressively with aging. In this study, protein-protein interaction network analysis indicated that high expression of Fgn is linked with downregulated expression of both BBB- and mitochondrial fission/fusion-related proteins in mice cortical MVs with aging. To investigate the mechanism of Fgn action, we observed that 2 mg/mL or higher concentration of human plasma Fgn changed cell morphology, induced cytotoxicity, and increased BBB permeability in primary human brain microvascular endothelial cells (HBMECs). The BBB tight junction proteins were significantly decreased with increasing concentration of human plasma Fgn in primary HBMECs. Similarly, the expression of phosphorylated dynamin-related protein 1 (pDRP1) and other mitochondrial fission/fusion-related proteins were also significantly reduced in Fgn-treated HBMECs. Interestingly, DRP1 knockdown by shRNA(h) resulted in the reduction of both BBB- and mitochondrial fission/fusion-related proteins in HBMECs. Our results suggest that elevated Fgn downregulates DRP1, leading to mitochondrial-dependent endothelial and BBB dysfunction in the brain microvasculature.

Rejuvenation of cerebromicrovascular function in aged mice through heterochronic parabiosis: insights into neurovascular coupling and the impact of young blood factors

Age-related impairment of neurovascular coupling (NVC; "functional hyperemia") is a critical factor in the development of vascular cognitive impairment (VCI). Recent geroscience research indicates that cell-autonomous mechanisms alone cannot explain all aspects of neurovascular aging. Circulating factors derived from other organs, including pro-geronic factors (increased with age and detrimental to vascular homeostasis) and anti-geronic factors (preventing cellular aging phenotypes and declining with age), are thought to orchestrate cellular aging processes. This study aimed to investigate the influence of age-related changes in circulating factors on neurovascular aging. Heterochronic parabiosis was utilized to assess how exposure to young or old systemic environments could modulate neurovascular aging. Results demonstrated a significant decline in NVC responses in aged mice subjected to isochronic parabiosis (20-month-old C57BL/6 mice [A-(A)]; 6 weeks of parabiosis) when compared to young isochronic parabionts (6-month-old, [Y-(Y)]). However, exposure to young blood from parabionts significantly improved NVC in aged heterochronic parabionts [A-(Y)]. Conversely, young mice exposed to old blood from aged parabionts exhibited impaired NVC responses [Y-(A)]. In conclusion, even a brief exposure to a youthful humoral environment can mitigate neurovascular aging phenotypes, rejuvenating NVC responses. Conversely, short-term exposure to an aged humoral milieu in young mice accelerates the acquisition of neurovascular aging traits. These findings highlight the plasticity of neurovascular aging and suggest the presence of circulating anti-geronic factors capable of rejuvenating the aging cerebral microcirculation. Further research is needed to explore whether young blood factors can extend their rejuvenating effects to address other age-related cerebromicrovascular pathologies, such as blood-brain barrier integrity.

Protective effect of melatonin on blood-brain barrier damage caused by Endotoxemia

OBJECTIVE

Endotoxins, products of Gram-negative bacteria, are the primary cause of blood-brain barrier (BBB) damage. In the present study, we aimed to investigate the possible neuroprotection mechanisms of melatonin on BBB damage induced by endotoxemia.

METHODS

Adult, female Sprague-Dawley rats (n = 42) were separated into four random groups as a control group and three treatment groups. Lipopolysaccharide (7,5 mg/kg/day) was administrated for a single dose to generate a 24-hour sepsis model on rats. Melatonin (10 mg/kg/day) was treated a week before sepsis. Afterward, the dissected brain tissues were examined by histopathological, biochemical, and molecular analyses.

RESULTS

LPS caused weight loss in the groups. As a result, degenerated neurons with cytoplasmic vacuoles and irregular pyknotic nuclei, pale stained necrotic neurons, and vascular congestion were observed in LPS-exposed rats. However, MEL decreased the number of degenerated neurons in treated groups. MEL treatment increased ZO1 and Occludin immunoreactivity while decreasing TLR4 in brain tissues. MEL effect on protein expression was recorded for ZO1 increase and TLR4 decrease in brain tissue compared to LPS groups. MEL also decreased MDA levels in brain tissue.

CONCLUSIONS

MEL recovered the degenerative damage of sepsis by contributing to blood-brain barrier integrity, and by decreasing inflammation, thus the neuroprotective effects of MEL might provide an experimental basis for clinical applications.

Role of Metalloproteinases in Diabetes-associated Mild Cognitive Impairment

Diabetes has been linked to an increased risk of mild cognitive impairment (MCI), a condition characterized by a subtle cognitive decline that may precede the development of dementia. The underlying mechanisms connecting diabetes and MCI involve complex interactions between metabolic dysregulation, inflammation, and neurodegeneration. A critical mechanism implicated in diabetes and MCI is the activation of inflammatory pathways. Chronic low-grade inflammation, as observed in diabetes, can lead to the production of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and interferon-gamma (IFNγ), each of which can exacerbate neuroinflammation and contribute to cognitive decline. A crucial enzyme involved in regulating inflammation is ADAM17, a disintegrin, and metalloproteinase, which can cleave and release TNF-α from its membrane-bound precursor and cause it to become activated. These processes, in turn, activate additional inflammation-related pathways, such as AKT, NF-κB, NLP3, MAPK, and JAK-STAT pathways. Recent research has provided novel insights into the role of ADAM17 in diabetes and neurodegenerative diseases. ADAM17 is upregulated in both diabetes and Alzheimer's disease, suggesting a shared mechanism and implicating inflammation as a possible contributor to much broader forms of pathology and pointing to a possible link between inflammation and the emergence of MCI. This review provides an overview of the different roles of ADAM17 in diabetes-associated mild cognitive impairment diseases. It identifies mechanistic connections through which ADAM17 and associated pathways may influence the emergence of mild cognitive impairment.

A latent clinical-anatomical dimension relating metabolic syndrome to brain structure and cognition

The link between metabolic syndrome (MetS) and neurodegenerative as well cerebrovascular conditions holds substantial implications for brain health in at-risk populations. This study elucidates the complex relationship between MetS and brain health by conducting a comprehensive examination of cardiometabolic risk factors, cortical morphology, and cognitive function in 40,087 individuals. Multivariate, data-driven statistics identified a latent dimension linking more severe MetS to widespread brain morphological abnormalities, accounting for up to 71% of shared variance in the data. This dimension was replicable across sub-samples. In a mediation analysis we could demonstrate that MetS-related brain morphological abnormalities mediated the link between MetS severity and cognitive performance in multiple domains. Employing imaging transcriptomics and connectomics, our results also suggest that MetS-related morphological abnormalities are linked to the regional cellular composition and macroscopic brain network organization. By leveraging extensive, multi-domain data combined with a dimensional stratification approach, our analysis provides profound insights into the association of MetS and brain health. These findings can inform effective therapeutic and risk mitigation strategies aimed at maintaining brain integrity.

Central mechanisms in sympathetic nervous dysregulation in obesity

Cardiovascular and metabolic complications associated with excess adiposity are linked to chronic activation of the sympathetic nervous system, resulting in a high risk of mortality among obese individuals. Obesity-related positive energy balance underlies the progression of hypertension, end-organ damage, and insulin resistance, driven by increased sympathetic tone throughout the body. It is, therefore, important to understand the central network that drives and maintains sustained activation of the sympathetic nervous system in the obese state. Experimental and clinical studies have identified structural changes and altered dynamics in both grey and white matter regions in obesity. Aberrant activation in certain brain regions has been associated with altered reward circuitry and metabolic pathways including leptin and insulin signaling along with adiposity-driven systemic and central inflammation. The impact of these pathways on the brain via overactivity of the sympathetic nervous system has gained interest in the past decade. Primarily, the brainstem, hypothalamus, amygdala, hippocampus, and cortical structures including the insular, orbitofrontal, temporal, cingulate, and prefrontal cortices have been identified in this context. Although the central network involving these structures is much more intricate, this review highlights recent evidence identifying these regions in sympathetic overactivity in obesity.

Exposome and unhealthy aging: environmental drivers from air pollution to occupational exposures

The aging population worldwide is facing a significant increase in age-related non-communicable diseases, including cardiovascular and brain pathologies. This comprehensive review paper delves into the impact of the exposome, which encompasses the totality of environmental exposures, on unhealthy aging. It explores how environmental factors contribute to the acceleration of aging processes, increase biological age, and facilitate the development and progression of a wide range of age-associated diseases. The impact of environmental factors on cognitive health and the development of chronic age-related diseases affecting the cardiovascular system and central nervous system is discussed, with a specific focus on Alzheimer's disease, Parkinson's disease, stroke, small vessel disease, and vascular cognitive impairment (VCI). Aging is a major risk factor for these diseases. Their pathogenesis involves cellular and molecular mechanisms of aging such as increased oxidative stress, impaired mitochondrial function, DNA damage, and inflammation and is influenced by environmental factors. Environmental toxicants, including ambient particulate matter, pesticides, heavy metals, and organic solvents, have been identified as significant contributors to cardiovascular and brain aging disorders. These toxicants can inflict both macro- and microvascular damage and many of them can also cross the blood-brain barrier, inducing neurotoxic effects, neuroinflammation, and neuronal dysfunction. In conclusion, environmental factors play a critical role in modulating cardiovascular and brain aging. A deeper understanding of how environmental toxicants exacerbate aging processes and contribute to the pathogenesis of neurodegenerative diseases, VCI, and dementia is crucial for the development of preventive strategies and interventions to promote cardiovascular, cerebrovascular, and brain health. By mitigating exposure to harmful environmental factors and promoting healthy aging, we can strive to reduce the burden of age-related cardiovascular and brain pathologies in the aging population.

Assessment of cerebral autoregulatory function and inter-hemispheric blood flow in older adults with internal carotid artery stenosis using transcranial Doppler sonography-based measurement of transient hyperemic response after carotid artery compression

Unhealthy vascular aging promotes atherogenesis, which may lead to significant internal carotid artery stenosis (CAS) in 5 to 7.5% of older adults. The pathogenic factors that promote accelerated vascular aging and CAS also affect the downstream portion of the cerebral microcirculation in these patients. Primary treatments of significant CAS are eversion endarterectomy or endarterectomy with patch plasty. Factors that determine adequate hemodynamic compensation and thereby the clinical consequences of CAS as well as medical and surgical complications of carotid reconstruction surgery likely involve the anatomy of the circle of Willis (CoW), the magnitude of compensatory inter-hemispheric blood flow, and the effectiveness of cerebral microcirculatory blood flow autoregulation. This study aimed to test two hypotheses based on this theory. First, we hypothesized that patients with symptomatic and asymptomatic CAS would exhibit differences in autoregulatory function and inter-hemispheric blood flow. Second, we predicted that anatomically compromised CoW would associate with impaired inter-hemispheric blood flow compensation. We enrolled older adults with symptomatic or asymptomatic internal CAS (>70% NASCET criteria; n = 46) and assessed CoW integrity by CT angiography. We evaluated transient hyperemic responses in the middle cerebral arteries (MCA) after common carotid artery compression (CCC; 10 s) by transcranial Doppler sonography (TCD). We compared parameters reflecting autoregulatory function (e.g., transient hyperemic response ratio [THRR], return to baseline time [RTB], changes of vascular resistance) and inter-hemispheric blood flow (residual blood flow velocity). Our findings revealed that CAS was associated with impaired cerebral vascular reactivity. However, we did not observe significant differences in autoregulatory function or inter-hemispheric blood flow between patients with symptomatic and asymptomatic CAS. Moreover, anatomically compromised CoW did not significantly affect these parameters. Notably, we observed an inverse correlation between RTB and THRR, and 49% of CAS patients exhibited a delayed THRR, which associated with decreased inter-hemispheric blood flow. Future studies should investigate how TCD-based evaluation of autoregulatory function and inter-hemispheric blood flow can be used to optimize surgical techniques and patient selection for internal carotid artery revascularization.

The multifaceted benefits of walking for healthy aging: from Blue Zones to molecular mechanisms

Physical activity, including walking, has numerous health benefits in older adults, supported by a plethora of observational and interventional studies. Walking decreases the risk or severity of various health outcomes such as cardiovascular and cerebrovascular diseases, type 2 diabetes mellitus, cognitive impairment and dementia, while also improving mental well-being, sleep, and longevity. Dose-response relationships for walking duration and intensity are established for adverse cardiovascular outcomes. Walking's favorable effects on cardiovascular risk factors are attributed to its impact on circulatory, cardiopulmonary, and immune function. Meeting current physical activity guidelines by walking briskly for 30 min per day for 5 days can reduce the risk of several age-associated diseases. Additionally, low-intensity physical exercise, including walking, exerts anti-aging effects and helps prevent age-related diseases, making it a powerful tool for promoting healthy aging. This is exemplified by the lifestyles of individuals in Blue Zones, regions of the world with the highest concentration of centenarians. Walking and other low-intensity physical activities contribute significantly to the longevity of individuals in these regions, with walking being an integral part of their daily lives. Thus, incorporating walking into daily routines and encouraging walking-based physical activity interventions can be an effective strategy for promoting healthy aging and improving health outcomes in all populations. The goal of this review is to provide an overview of the vast and consistent evidence supporting the health benefits of physical activity, with a specific focus on walking, and to discuss the impact of walking on various health outcomes, including the prevention of age-related diseases. Furthermore, this review will delve into the evidence on the impact of walking and low-intensity physical activity on specific molecular and cellular mechanisms of aging, providing insights into the underlying biological mechanisms through which walking exerts its beneficial anti-aging effects.

Glucose Transport and Utilization in the Hippocampus: From Neurophysiology to Diabetes-Related Development of Dementia

The association of diabetes with cognitive dysfunction has at least 60 years of history, which started with the observation that children with type 1 diabetes mellitus (T1D), who had recurrent episodes of hypoglycemia and consequently low glucose supply to the brain, showed a deficit of cognitive capacity. Later, the growing incidence of type 2 diabetes mellitus (T2D) and dementia in aged populations revealed their high association, in which a reduced neuronal glucose supply has also been considered as a key mechanism, despite hyperglycemia. Here, we discuss the role of glucose in neuronal functioning/preservation, and how peripheral blood glucose accesses the neuronal intracellular compartment, including the exquisite glucose flux across the blood-brain barrier (BBB) and the complex network of glucose transporters, in dementia-related areas such as the hippocampus. In addition, insulin resistance-induced abnormalities in the hippocampus of obese/T2D patients, such as inflammatory stress, oxidative stress, and mitochondrial stress, increased generation of advanced glycated end products and BBB dysfunction, as well as their association with dementia/Alzheimer's disease, are addressed. Finally, we discuss how these abnormalities are accompained by the reduction in the expression and translocation of the high capacity insulin-sensitive glucose transporter GLUT4 in hippocampal neurons, which leads to neurocytoglycopenia and eventually to cognitive dysfunction. This knowledge should further encourage investigations into the beneficial effects of promising therapeutic approaches which could improve central insulin sensitivity and GLUT4 expression, to fight diabetes-related cognitive dysfunctions.

Nicotinamide, an acetylcholinesterase uncompetitive inhibitor, protects the blood‒brain barrier and improves cognitive function in rats fed a hypercaloric diet

Oxidative stress and inflammation induced by abundant consumption of high-energy foods and caloric overload are implicated in the dysfunction of the blood‒brain barrier (BBB), cognitive impairment, and overactivation of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These enzymes hydrolyse acetylcholine, affecting anti-inflammatory cholinergic signalling. Our aim was to evaluate whether nicotinamide (NAM) attenuates the impairment of the BBB and cognitive function, improving cholinergic signalling. Forty male rats were distributed into five groups: one group was fed a standard diet, and the remaining groups were fed a high-fat diet and a beverage with 40% sucrose (HFS; high-fat sucrose). In three of the HFS groups, the carbohydrate was replaced by drinking water containing different concentrations of NAM for 5 h every morning for 12 weeks. The biochemical profile, levels of stress and inflammation markers, cholinesterase activities, BBB permeability, and cognitive capacity were evaluated. The results showed that the HFS diet disturbed the metabolism of carbohydrates and lipids, causing insulin resistance. Simultaneously, AChE and BChE activities, levels of proinflammatory cytokines, oxidation of proteins and lipoperoxidation increased along with decreased antioxidant capacity in serum. In the hippocampus, increased activity of cholinesterases, protein carbonylation and lipoperoxidation were associated with decreased antioxidant capacity. Systemic and hippocampal changes were reflected in increased BBB permeability and cognitive impairment. In contrast, NAM attenuated the above changes by reducing oxidative stress and inflammation through decreasing cholinesterase activities, especially by uncompetitive inhibition. NAM may be a potential systemic and neuroprotective agent to mitigate cognitive damage due to hypercaloric diets.

The Role of Methionine-Rich Diet in Unhealthy Cerebrovascular and Brain Aging: Mechanisms and Implications for Cognitive Impairment

As aging societies in the western world face a growing prevalence of vascular cognitive impairment and Alzheimer's disease (AD), understanding their underlying causes and associated risk factors becomes increasingly critical. A salient concern in the western dietary context is the high consumption of methionine-rich foods such as red meat. The present review delves into the impact of this methionine-heavy diet and the resultant hyperhomocysteinemia on accelerated cerebrovascular and brain aging, emphasizing their potential roles in cognitive impairment. Through a comprehensive exploration of existing evidence, a link between high methionine intake and hyperhomocysteinemia and oxidative stress, mitochondrial dysfunction, inflammation, and accelerated epigenetic aging is drawn. Moreover, the microvascular determinants of cognitive deterioration, including endothelial dysfunction, reduced cerebral blood flow, microvascular rarefaction, impaired neurovascular coupling, and blood-brain barrier (BBB) disruption, are explored. The mechanisms by which excessive methionine consumption and hyperhomocysteinemia might drive cerebromicrovascular and brain aging processes are elucidated. By presenting an intricate understanding of the relationships among methionine-rich diets, hyperhomocysteinemia, cerebrovascular and brain aging, and cognitive impairment, avenues for future research and potential therapeutic interventions are suggested.

Pericyte loss impairs the blood-brain barrier and cognitive function in aged mice after anesthesia/surgery

AIMS

This study was designed to investigate the role of pericytes in the pathogenesis of perioperative neurocognitive disorder (PND).

METHODS

In this study, we established a PND model via sevoflurane anesthesia and tibial fracture surgery in 2-month-old and 16-month-old male C57BL/6 mice. On the third postoperative day, the mice were subjected to behavioral testing or sacrificed to collect brain tissue. The progression of hippocampal blood-brain barrier (BBB) disruption and neuroinflammation was detected using transmission electron microscope and immunofluorescence. We also used western blotting to measure the levels of plasma-derived protein immunoglobulin G (IgG) and albumin in the hippocampus to assess the leakage of the BBB.

RESULTS

Aged mice did not experience age-related cognitive decline and BBB disruption compared with younger mice but only increased glial cell activity. Anesthesia/Surgery damaged cognitive function, reduced pericyte coverage, decreased the length of capillaries and levels of occludin and claudin-5, destroyed the structure of the BBB, exacerbated IgG and albumin accumulation in the hippocampus, and enhanced the activation of microglia and astrocytes in the hippocampus of aged mice. However, these negative effects did not occur in young mice.

CONCLUSION

Our study showed that the loss of pericytes led to increased BBB permeability and neuroinflammation after anesthesia/surgery in aged mice, ultimately resulting in cognitive dysfunction.

Obesity exacerbates postoperative cognitive dysfunction by activating the PARP1/NAD+/SIRT1 axis through oxidative stress

The purposes of this study were to explore the impact of obesity on postoperative cognitive dysfunction (POCD) and to investigate the underlying mechanism by which obesity exacerbates POCD. In this study, fifteen-month-old male C57BL/6 J mice were fed a High-fat diet for three months to establish obesity models. Internal fixation of tibial fractures under isoflurane inhalation was performed to construct a POCD animal model. Three days after surgery, mice were subjected to the Morris water maze (MWM) experiment to evaluate their learning and memory abilities. The findings from the MWM experiment revealed that in comparison to the Ad Libitum Surgical group (ALS), mice in the High-fat Surgical group (HFS) exhibited prolonged escape latencies and reduced platform crossings. These outcomes suggest the potential exacerbating role of obesity in cognitive impairment within the POCD mouse models. Immunofluorescence (IF) findings demonstrate that obesity intensifies anesthesia and surgery-induced oxidative stress levels within the hippocampus. Compared to the Ad Libitum Control group (ALC), an elevation in PARP1 expression and a reduction in the NAD+/NADH ratio and SIRT1 expression were observed in the hippocampus of mice from the ALS. Moreover, when contrasting the HFS group with the ALS group, increased PARP1 expression along with decreased NAD+/NADH ratio and SIRT1 expression were evident. In vitro studies found that compared with the Control group (CON), oil red staining and BODIPY probe staining showed significant lipid droplet aggregation in the palmitic acid (PA) group. IF results demonstrated that HT22 cells in the PA group experienced oxidative stress and activation of the PARP1/NAD+/SIRT1 axis in contrast to the CON group. Moreover, manipulation of PARP1 expression in HT22 cells through PARP1 lentivirus-based silencing or overexpression revealed a converse relationship between PARP1 expression levels and the NAD+/NADH ratio as well as SIRT1 expression levels. This study concludes that obesity may exacerbate POCD by triggering activation of the oxidative stress-induced PARP1/NAD+/SIRT1 axis.