Glucosamine Enhancement of BDNF Expression and Animal Cognitive Function

Role of brain-derived neurotrophic factor in frailty: From mechanisms to interventions

Frailty is a common medical syndrome which largely increases the risk of disability, depression, falls, hospitalization and mortality. An increasing number of research suggests that frailty is reversible by medical interventions at its early stage. Therefore, efficient detection is utterly important for frail population. Since numerous biological processes have been indicated in frail population, the critical regulators in these biological processes could provide biomarkers for early detection or treatment for frailty. The brain-derived neurotrophic factor (BDNF) has been associated with several biological process ranging from cognitive function to inflammation, therefore it could be an important regulator for frailty. In this review, we would discuss the mechanism association between different indicators of frailty and BDNF. Furthermore, we summarize the approaches to interfere with BDNF in healthy and pathologic condition, which could lead to identification of potential interventional strategies for frailty.

Association between outdoor artificial light at night and executive function among depressive patients: the mediating effect of sleep timing

Recent evidence highlights the potential impact of outdoor artificial light at night (ALAN) on sleep, and later sleep timing may be a risk factor for executive dysfunction. Depression is commonly associated with executive dysfunction, which significantly compromise prognosis. However, it remains unclear whether sleep-wake phase mediate the effects of outdoor ALAN on executive function. We assessed whether sleep timing mediated the association between outdoor ALAN and executive function among depressed patients. Between 2017 and 2023, 798 inpatients with depression were enrolled from the Fourth People's Hospital of Hefei. The outdoor ALAN exposure of patients was estimated using satellite images. All participants were assessed for sleep conditions using the Pittsburgh Sleep Quality Index (PSQI) and for executive function using the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A). We employed multifactor linear regression models to investigate the association between outdoor ALAN exposure and executive function, adjusted for potential confounders. Additionally, mediation models were utilized to explore the mediating role of sleep timing in this association. Our study found that greater ALAN exposure was significantly associated with higher executive function scores. The exposure of participants at 12 months prior to enrollment had the greatest effect, for each interquartile range (IQR 29.93 nW/cm2/sr) increase in outdoor ALAN exposure, the Global Executive Composite (GEC) scores increased by 6.12 (95 % confidence interval [CI]: 2.49, 9.74). Mediation analysis indicated that sleep midpoint significantly mediated the relationship between outdoor ALAN and executive function, with a mediated proportion of 22.39 %. The study suggested that outdoor ALAN exposure has adverse effects on executive function in depressed patients, and sleep-wake phase may mediate the association between outdoor ALAN exposure and executive function.

The Cognitive Footprint of Medication Use

INTRODUCTION

The cognitive side-effects of medication are common, but often overlooked in practice, and not routinely considered in interventional trials or post-market surveillance. The cognitive footprint of a medication seeks to quantify the impact of its cognitive effects based on magnitude, duration, and interaction with other factors, evaluated across the exposed population.

METHODS

Bayesian multivariable regression analysis of retrospective population-based cross-sectional cohorts.

RESULTS

We replicate positive and negative cognitive effects of commonly used medications in UK Biobank, and extend observed associations to two additional cohorts, the EPIC Norfolk, and the Caerphilly Prospective Cohort. We quantify the resultant cumulative impact at the population level given known patterns of prescribing and compare it with exemplar common diseases.

CONCLUSION

The cognitive side-effects of commonly used drugs may have significant impact at the population level. Consideration should be given to a routine structured assessment of cognition in interventional trials and post-market surveillance.

Causality of genetically determined glucosamine supplementation on cognition and sarcopenia: a Mendelian randomization study

BACKGROUND

Evidence indicates a negative link between glucosamine and age-related cognitive decline and sarcopenia. However, the causal relationship remains uncertain. This study aims to verify whether glucosamine is causally associated with cognitive function and sarcopenia.

METHOD

Forty-eight genetic variants linked to glucosamine use were extracted from the MRC-IEU consortium. Besides, we gathered cognition proxy indicators [cognitive performance and fluid intelligence score (FIS)], and sarcopenia-related indicators, namely, appendicular lean mass (ALM), whole body fat-free mass (WBFM), low hand grip strength, facial aging (FA), moderate to vigorous physical activity levels, usual walking pace and DNA methylation GrimAge acceleration from the large publicly available genome-wide association studies. Initially, Mendelian randomization (MR) analyses were conducted to ascertain the causal impact of glucosamine on cognition and sarcopenia-related traits. Subsequently, the two-step MR and multivariable MR (MVMR) were employed to examine whether any mediators causally mediated the observed associations.

RESULT

MR analysis indicated that glucosamine was associated with increased cognitive performance (p = 8.46E-04), FIS (p = 7.50E-04), ALM (p = 6.45E-08), WBFM (p = 1.97E-03), usual walking pace (p = 2.55E-07), and moderate to vigorous physical activity levels (p = 3.29E-03), but associated with decreased FA risk (p = 3.77E-05) and DNA methylation GrimAge acceleration (p = 0.001). However, there were no significant causal associations between glucosamine and low hand grip strength. Multivariable MR showed that glucosamine continued to have a significant effect on cognitive performance, FIS, ALM, WBFM, usual walking pace, and moderate to vigorous physical activity levels after controlling for osteoarthritis (OA) and body mass index (BMI) (p < 0.05). We further found that C-reactive protein levels (CRP) may mediate the association of glucosamine and ALM, WBFM, usual walking pace, and physical activity (p < 0.05), and basal metabolic rate (BMR) may mediate the association of glucosamine and cognitive performance, FIS, ALM, WBFM, and usual walking pace (p < 0.05).

CONCLUSION

Regular glucosamine use enhances cognitive function and postpones sarcopenia for preserving the functional capacities necessary, and the impact of glucosamine on cognition and sarcopenia could be partially attributed to the mediation of BMR and CRP.

Glucosamine Enhancement of Learning and Memory Functions by Promoting Fibroblast Growth Factor 21 Production

Fibroblast growth factor 21 (FGF21) plays a crucial role in metabolism and brain function. Glucosamine (GLN) has been recognized for its diverse beneficial effects. This study aimed to elucidate the modulation of FGF21 production by GLN and its impact on learning and memory functions. Using both in vivo and in vitro models, we investigated the effects of GLN on mice fed with a normal diet or high-fat diet and on mouse HT22 hippocampal cells, STHdhQ7/Q7 striatal cells, and rat primary cortical neurons challenged with GLN. Our results indicated that GLN promotes learning and memory functions in mice and upregulates FGF21 expression in the hippocampus, cortex, and striatum, as well as in HT22 cells, STHdhQ7/Q7 cells, and cortical neurons. In animals receiving GLN together with an FGF21 receptor FGFR1 inhibitor (PD173074), the GLN-enhanced learning and memory functions and induction of FGF21 production in the hippocampus were significantly attenuated. While exploring the underlying molecular mechanisms, the potential involvement of NF-κB, Akt, p38, JNK, PKA, and PPARα in HT22 and NF-κB, Akt, p38, and PPARα in STHdhQ7/Q7 were noted; GLN was able to mediate the activation of p65, Akt, p38, and CREB in HT22 and p65, Akt, and p38 in STHdhQ7/Q7 cells. Our accumulated findings suggest that GLN may increase learning and memory functions by inducing FGF21 production in the brain. This induction appears to be mediated, at least in part, through GLN's activation of the NF-κB, Akt, p38, and PKA/CREB pathways.

The prenatal use of agmatine prevents social behavior deficits in VPA-exposed mice by activating the ERK/CREB/BDNF signaling pathway

BACKGROUND

According to reports, prenatal exposure to valproic acid can induce autism spectrum disorder (ASD)-like symptoms in both humans and rodents. However, the exact cause and therapeutic method of ASD is not fully understood. Agmatine (AGM) is known for its neuroprotective effects, and this study aims to explore whether giving agmatine hydrochloride before birth can prevent autism-like behaviors in mouse offspring exposed prenatally to valproic acid.

METHODS

In this study, we investigated the effects of AGM prenatally on valproate (VPA)-exposed mice. We established a mouse model of ASD by prenatally administering VPA. From birth to weaning, we evaluated mouse behavior using the marble burying test, open-field test, and three-chamber social interaction test on male offspring.

RESULTS

The results showed prenatal use of AGM relieved anxiety and hyperactivity behaviors as well as ameliorated sociability of VPA-exposed mice in the marble burying test, open-field test, and three-chamber social interaction test, and this protective effect might be attributed to the activation of the ERK/CREB/BDNF signaling pathway.

CONCLUSION

Therefore, AGM can effectively reduce the likelihood of offspring developing autism to a certain extent when exposed to VPA during pregnancy, serving as a potential therapeutic drug.

No Associations Between Glucosamine Supplementation and Dementia or Parkinson's Disease: Findings From a Large Prospective Cohort Study

BACKGROUND

We investigated the associations between habitual use of glucosamine and incident dementia and Parkinson's disease in a population-based cohort.

METHODS

Using the UK Biobank data, we included around 0.29 million middle- to old-aged participants free of dementia or Parkinson's disease at baseline. Glucosamine supplementation was measured by questionnaire at baseline. Some participants additionally answered 1-5 rounds of 24-hour dietary recalls afterwards, particularly 112 243 participants (for dementia) and 112 084 (for Parkinson's disease). Incident cases of dementia and Parkinson's disease were identified through linkage to health administrative data sets. We examined the associations of glucosamine supplementation with incident dementia and Parkinson's disease using Cox proportional-hazards regression models with adjustment for various covariates.

RESULTS

During the study period (median follow-up: 9.1-10.9 years), 4 404 and 1 637 participants developed dementia and Parkinson's disease, respectively. Glucosamine intake was not associated with incident dementia or Parkinson's disease. In fully adjusted models, the hazard ratios associated with glucosamine intake were 1.06 [95% confidence interval (CI): 0.99, 1.14] for dementia and 0.97(95% CI: 0.86, 1.09) for Parkinson's disease. In the subsample, similar results were found as the frequency of reported glucosamine use over multiple dietary surveys was associated with neither of the 2 conditions.

CONCLUSIONS

Habitual supplementation of glucosamine was not associated with incident dementia or Parkinson's disease.

Habitual glucosamine use, APOE genotypes, and risk of incident cause-specific dementia in the older population

BACKGROUND

The relationship of glucosamine use with incident dementia in the older population remains uncertain. We aimed to evaluate the longitudinal association between habitual glucosamine supplement and the risk of cause-specific dementia and examine the possible effect modifiers on this association.

METHODS

The study included 214,945 participants over the age of 60 who had available information on glucosamine use and did not have dementia at baseline in the UK Biobank. The APOE genotypes were determined by a combination variant of rs429358 and rs7412. The primary outcome was incident vascular dementia, incident Alzheimer's disease, and incident frontotemporal dementia, respectively.

RESULTS

Over a median follow-up duration of 12 years, 1039, 1774, and 122 participants developed vascular dementia, Alzheimer's disease, and frontotemporal dementia, respectively. Overall, habitual glucosamine use was significantly associated with a lower risk of incident vascular dementia (adjusted HR, 0.82; 95%CI, 0.70-0.96), but not significantly associated with incident Alzheimer's disease (adjusted HR, 1.02; 95%CI, 0.92-1.14) and incident frontotemporal dementia (adjusted HR, 0.95; 95%CI, 0.63-1.43). Moreover, the inverse association between habitual glucosamine use and incident vascular dementia was more pronounced in participants with concomitant supplement of calcium (P-interaction = 0.011), and those without concomitant supplement of zinc (P-interaction = 0.018). However, APOE ε4 dosage and baseline cognitive function did not significantly modify the relationships of glucosamine use with incident vascular dementia or Alzheimer's disease (All P-interactions > 0.05).

CONCLUSIONS

Regardless of APOE genotypes and baseline cognitive function, habitual glucosamine use was significantly inversely associated with incident vascular dementia in the older population.

Association of regular glucosamine use with incident dementia: evidence from a longitudinal cohort and Mendelian randomization study

BACKGROUND

Emerging data suggests the neuroprotective and anti-neuroinflammatory effects of glucosamine. We aimed to examine the association between regular glucosamine use and risk of incident dementia, including dementia subtypes.

METHODS

We conducted large-scale observational and two-sample Mendelian randomization (MR) analyses. Participants in UK Biobank having accessible data for dementia incidence and who did not have dementia at baseline were included in the prospective cohort. Through the Cox proportional hazard model, we examined the risks of incident all-cause dementia, Alzheimer's disease (AD), and vascular dementia among glucosamine users and non-users. To further test the causal association between glucosamine use and dementia, we conducted a 2-sample MR utilizing summary statistics from genome-wide association studies (GWAS). The GWAS data were obtained from observational cohort participants of mostly European ancestry.

RESULTS

During a median follow-up of 8.9 years, there were 2458 cases of all-cause dementia, 924 cases of AD, and 491 cases of vascular dementia. In multivariable analysis, the hazard ratios (HR) of glucosamine users for all-cause dementia, AD, and vascular dementia were 0.84 (95% CI 0.75-0.93), 0.83 (95% CI 0.71-0.98), and 0.74 (95% CI 0.58-0.95), respectively. The inverse associations between glucosamine use and AD appeared to be stronger among participants aged below 60 years than those aged above 60 years (p = 0.04 for interaction). The APOE genotype did not modify this association (p > 0.05 for interaction). Single-variable MR suggested a causal relationship between glucosamine use and lower dementia risk. Multivariable MR showed that taking glucosamine continued to protect against dementia after controlling for vitamin, chondroitin supplement use and osteoarthritis (all-cause dementia HR 0.88, 95% CI 0.81-0.95; AD HR 0.78, 95% CI 0.72-0.85; vascular dementia HR 0.73, 95% CI 0.57-0.94). Single and multivariable inverse variance weighted (MV-IVW) and MR-Egger sensitivity analyses produced similar results for these estimations.

CONCLUSIONS

The findings of this large-scale cohort and MR analysis provide evidence for potential causal associations between the glucosamine use and lower risk for dementia. These findings require further validation through randomized controlled trials.

Resveratrol Ameliorates Trigeminal Neuralgia-Induced Cognitive Deficits by Regulating Neural Ultrastructural Remodelling and the CREB/BDNF Pathway in Rats

Chronic pain often leads to cognitive impairment. Resveratrol (Res), a natural polyphenol existing in Polygonum cuspidatum, has been widely investigated for its antinociceptive, anti-inflammatory, and neuroprotective properties. Our aim was to explore the ameliorating effects of resveratrol on pain-related behaviors and learning and memory deficits induced by cobra venom-induced trigeminal neuralgia (TN). The TN model of rats was established by injecting cobra venom solution beneath the epineurium of the infraorbital nerve. Resveratrol was intragastrically administered at a dose of 40 mg/kg twice daily beginning on postoperative day 15. CREB inhibitor 666-15 was intraperitoneally administered at a dose of 10 mg/kg from POD 35-42 after morning resveratrol treatment. Mechanical allodynia was measured via von Frey filaments. Rat free movement was videotaped and analyzed. Spatial learning and memory were evaluated via the Morris water maze test. Ultrastructures of the hippocampal DG region and infraorbital nerve were observed by transmission electron microscopy. We found that resveratrol alleviated TN-induced allodynia, ameliorated learning and memory deficits, restored the ultrastructure of hippocampal neurons and synapses, repaired the damaged myelin sheath of the infraorbital nerve, and activated the CREB/BDNF pathway in the hippocampus of TN rats. CREB inhibitor administration suppressed the resveratrol-rescued abnormal hippocampal ultrastructural changes and aggravated spatial learning and memory impairment by inhibiting CREB/BDNF pathway activation in the hippocampus. Our findings indicated that resveratrol alleviated pain and improved cognitive deficits, probably by regulating neural ultrastructure remodelling and the CREB/BDNF pathway.

Forsythoside B ameliorates diabetic cognitive dysfunction by inhibiting hippocampal neuroinflammation and reducing synaptic dysfunction in ovariectomized mice

BACKGROUND

Diabetes-associated cognitive impairment (DACI) is a common complication of diabetes, and studies have shown that DACI is more severe in postmenopausal patients with diabetes. Forsythoside B (FTS⋅B) can inhibit inflammation and reduce synaptic dysfunction, which can improve cognitive function. However, it has not been confirmed whether FTS⋅B has a reversing or retarding effect on postmenopausal diabetic encephalopathy.

METHODS

Seven days after bilateral ovariectomy (OVX) or sham surgery, adult female C57 mice (n = 15/group) received intraperitoneal injection of streptozotocin (60 mg/kg/day/L) and citrate buffer for 5 consecutive days to induce diabetes mellitus (DM). Fourteen days later, ovariectomized diabetic mice were given intraperitoneal injection of FTS⋅B (100, 150 mg/kg/day/L) and subcutaneous injection of 17β-estradiol (1 mg/kg) for 8 weeks [OVX + DM + low-FTS⋅B group (L-F), OVX + DM + high-FTS⋅B group (H-F), and OVX + DM + 17β-estradiol (ER)]. In addition, the following control groups were defined: Sham, OVX, DM, and OVX + DM (O + D). Fasting plasma glucose, body weight and blood insulin levels were determined in each group of mice. Next, their cognitive function was tested through behavioral experiments. Hematoxylin & eosin (H&E) and Nissl staining were used to detect the morphological changes in the hippocampus. The aggregation of amyloid beta (Aβ) and the hyperaggregation of p-tau were assessed by immunohistochemistry. Interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), brain-derived neurotrophic factor (BDNF), post-synaptic density-95 (PSD-95), synaptophysin, and synapsin-1 expression in the hippocampus was detected by real-time polymerase chain reaction (RT-PCR) and western blot analysis.

RESULTS

FTS⋅B can decrease fasting glucose and blood insulin level. Behavioral results showed that cognitive decline was the most severe in the O + D group, and the ER, L-F, and H-F groups revised the cognitive decline. Compared to the O + D group, more normal morphology, which has obvious nucleoli and clear nuclear membrane, was observed by H&E and Nissl staining in the ER, L-F, and H-F groups. FTS⋅B alleviated DACI by reducing the aggregation of Aβ and the hyperaggregation of p-tau in the hippocampus. Moreover, the protein and mRNA expression showed that FTS⋅B not only inhibited inflammation by decreasing IL-1β, IL-6, and TNF-α but also modulated synaptic plasticity by increasing BDNF, PSD-95, synaptophysin, and synapsin-1.

CONCLUSION

These results suggest that FTS⋅B may be a novel therapeutic target for postmenopausal diabetic encephalopathy treatment.

Non-invasive, targeted, and non-viral ultrasound-mediated brain-derived neurotrophic factor plasmid delivery for treatment of autism in a rat model

Autism has clinical manifestations such as social interaction disorder, speech and intellectual development disorder, narrow interest range, and stereotyped and repetitive behavior, all of which bring considerable economic and mental burden to society and families, and represent a public health problem requiring urgent attention. Brain-derived neurotrophic factor (BDNF) plays an important role in supporting survival, differentiation, growth, and synapse formation of neurons and participates in the plasticity of nerves. However, it is difficult for BDNF to penetrate the blood-brain barrier (BBB) due to its large molecular weight. Low-frequency focused ultrasound (FUS) combined with microbubbles (MBs) has been demonstrated to be a promising method for opening the BBB non-invasively, transiently, and locally. Here, we studied the therapeutic effect of FUS combined with BDNF plasmid-loaded cationic microbubbles (BDNFp-CMBs) in a rat model of autism. BDNF-CMBs were prepared and the transfection efficiency of FUS combined with BDNF-CMBs was tested in vitro. A rat model of autism was established from the juvenile male offspring of Sprague-Dawley (SD) pregnant rats treated with sodium valproate (VPA) solution through intraperitoneal injection. The autism rats were randomized into three groups: the VPA group, which received no treatment, the BDNFp group, which was treated by injection of BDNFp, and the FUS + BDNFp-CMBs group, which was administered FUS combined with BDNFp-CMBs. Age-matched normal rats served as the control group (Con). Following treatment, stereotyped, exploratory, and social–behavioral tests were performed on the animals in each group. The rat brains were then collected for subsequent histological examination, and the changes in synaptic structures in the prefrontal cortex (PFC) were detected under transmission electron microscopy. The results showed that the constructed BDNFp could be loaded onto CMBs with high loading efficiency. The BDNFp-CMBs prepared in this study showed good stability in vivo. FUS combined BDNFp-CMBs could effectively and non-invasively open the BBB of rats. The stereotyped, exploratory, and social behaviors of the FUS + BDNFp-CMBs group were significantly improved. Compared to the VPA group, the abnormality of neuronal morphology and number in the PFC of the FUS + BDNFp-CMBs was alleviated to a certain extent and was accompanied by restoration of the damaged synapses in the encephalic region. Our work demonstrates the positive therapeutic effect of BDNF delivered by FUS non-invasively across the BBB into the PFC in a rat model of autism, offering a potential strategy for treating autism.

Liraglutide Improves Cognitive and Neuronal Function in 3-NP Rat Model of Huntington's Disease

Huntington’s disease (HD) is an autosomal dominant inherited neurodegenerative disease characterized by progressive motor, psychiatric, and cognitive abnormalities. The antidiabetic drug liraglutide possesses a neuroprotective potential against several neurodegenerative disorders; however, its role in Huntington’s disease (HD) and the possible mechanisms/trajectories remain elusive, which is the aim of this work. Liraglutide (200 μg/kg, s.c) was administered to rats intoxicated with 3-nitropropionic acid (3-NP) for 4 weeks post HD model induction. Liraglutide abated the 3-NP-induced neurobehavioral deficits (open field and elevated plus maze tests) and histopathological changes. Liraglutide downregulated the striatal mRNA expression of HSP 27, PBR, and GFAP, while it upregulated that of DARPP32. On the molecular level, liraglutide enhanced striatal miR-130a gene expression and TrKB protein expression and its ligand BDNF, while it reduced the striatal protein content and mRNA expression of the death receptors sortilin and p75NTR, respectively. It enhanced the neuroprotective molecules cAMP, p-PI3K, p-Akt, and p-CREB, besides modulating the p-GSK-3β/p-β-catenin axis. Liraglutide enhanced the antioxidant transcription factor Nrf2, abrogated TBARS, upregulated both Bcl2 and Bcl-XL, and downregulated Bax along with decreasing caspase-3 activity. Therefore, liraglutide exerts a neurotherapeutic effect on 3-NP-treated rats that is, besides the upturn of behavioral and structural findings, it at least partially, increased miR-130a and modulated PI3K/Akt/CREB/BDNF/TrKB, sortilin, and p75NTR, and Akt/GSK-3β/p-β-catenin trajectories besides its capacity to decrease apoptosis and oxidative stress, as well as its neurotrophic activity.

The impact of glucosamine on age-related macular degeneration in patients: A nationwide, population-based cohort study

Purpose

To analyze the association between glucosamine (GlcN) use and the risk of age-related macular degeneration (AMD) using claims data from the National Health Insurance Research Database (NHIRD).

Methods

A retrospective, population-based study was conducted with NHIRD data from a 14-year period (2000–2013). Chi-squared and Student’s t-tests were used to evaluate differences between the study and comparison cohorts for categorical and continuous variables, respectively. Risk factors for disease development were examined by the adjusted hazard ratio (aHR) with 95% confidence interval. Kaplan-Meier analysis was performed to compare the cumulative risk of AMD between the two cohorts.

Results

In total, 1,344 patients with GlcN treatment were enrolled in the study cohort and 5,376 patients without GlcN use were enrolled in the comparison cohort. The incidence rate of AMD was lower with GlcN use (3.65%) than without GlcN use (5.26%) (P = 0.014). GlcN use was associated with a lower risk of developing AMD among patients with hyperlipidemia, coronary artery disease, chronic obstructive pulmonary disease, stroke, other neurological disorders, or degenerative arthritis. Although the incidence of wet type AMD did not significantly differ (P = 0.91), the incidence of dry type AMD was lower in patients with GlcN use (2.9%) than those without GlcN use (4.84%) (P = 0.003). Kaplan-Meier analysis similarly revealed a lower rate of dry type AMD in patients with GlcN use compared to those without GlcN use (log-rank P = 0.004).

Conclusions

GlcN treatment can decrease the risk of developing dry type AMD. Further prospective controlled studies are needed to determine the effectiveness of GlcN treatment in patients with AMD and the associated mechanism.

Voluntary wheel running is capable of improving cognitive function only in the young but not the middle-aged male APPSwe/PS1De9 mice

To determine whether voluntary wheel running could improve cognitive function from both the young and middle-aged APP/PS1 mice and the underlying mechanisms involved in. Young (9-weeks old) and middle-aged (24-weeks old) APP/PS1 mice were randomly assigned into control and exercise groups, respectively. Mice from exercise group had free and unlimited access to the running wheel for a total of 16 weeks. Voluntary exercise only improved cognitive function from young but not the middle-aged APP/PS1 mice. This might be owing to that in young APP/PS1 mice voluntary exercise reduced tau phosphorylation via inhibiting p-GSK3β activity, as well as reduced neuro-inflammation and elevated key proteins involved in synaptic plasticity. Additionally, exercise also elevated circulating L-Valine, Glucosamine, Formylanthranilic acid, Myristic acid level and improved gut microbiota profiles (i.e. elevated Oscillibacter, EF097061_g, EU454870_g, EU504554_g, EU505046_g and EF096172_g and reduced Alistipes). Improved circulating metabolites and intestinal microbiome might also contribute to improved learning and memory abilities post exercise. For the middle-aged APP/PS1 mice, exercise reduced ADAM10 and GFAP protein expression in hippocampus, with no notable alterations in circulating metabolites; additionally, mice from exercise group had markedly reduced abundance of the phyla Proteobacteria and Tenericutes, genera Bacteroides and Faecalibacterium, and elevated abundance of the genera Allobaculum. It is suggested that voluntary exercise should be initiated at an early adulthood period rather than at late stage in order to prevent cognitive decline or Alzheimer's disease.