Biomarkers of oxidative and nitrosative damage in Alzheimer's disease and mild cognitive impairment

Embracing complexity of (brain) aging

Aging is a multifactorial process occurring in a pathophysiological continuum which leads to organ and system functional loss. While aging is not a disease, its pathophysiological continuum predisposes to illness and multimorbidity clusters which share common biomolecular mechanisms-the pillars of aging. Brain aging and neurodegeneration share many hallmarks with other age-related diseases. The central nervous system is often the weakest link susceptible to the aging process and its deterioration, resulting in cognitive impairment and other symptoms; the aging process is associated with proteostasis collapse, stem cell exhaustion, repair mechanisms, altered brain nutrient sensing, endothelial changes, inflammation, oxidative distress, and energy unbalance, as well as other disturbances. These mechanisms are highly interwoven, and considerable research is aimed at their disentanglement and detection of their clinically relevant impact, particularly in order to identify pharmacological and non-pharmacological preventive and therapeutic strategies.

Exploring the significance of lipids in Alzheimer's disease and the potential of extracellular vesicles

Lipids play a significant role in maintaining central nervous system (CNS) structure and function, and the dysregulation of lipid metabolism is known to occur in many neurological disorders, including Alzheimer's disease. Here we review what is currently known about lipid dyshomeostasis in Alzheimer's disease. We propose that small extracellular vesicle (sEV) lipids may provide insight into the pathophysiology and progression of Alzheimer's disease. This stems from the recognition that sEV likely contributes to disease pathogenesis, but also an understanding that sEV can serve as a source of potential biomarkers. While the protein and RNA content of sEV in the CNS diseases have been studied extensively, our understanding of the lipidome of sEV in the CNS is still in its infancy.

Endoplasmic reticulum stress and its role in various neurodegenerative diseases

The Endoplasmic reticulum (ER), a critical cellular organelle, maintains cellular homeostasis by regulating calcium levels and orchestrating essential functions such as protein synthesis, folding, and lipid production. A pivotal aspect of ER function is its role in protein quality control. When misfolded proteins accumulate within the ER due to factors like protein folding chaperone dysfunction, toxicity, oxidative stress, or inflammation, it triggers the Unfolded protein response (UPR). The UPR involves the activation of chaperones like calnexin, calreticulin, glucose-regulating protein 78 (GRP78), and Glucose-regulating protein 94 (GRP94), along with oxidoreductases like protein disulphide isomerases (PDIs). Cells employ the Endoplasmic reticulum-associated degradation (ERAD) mechanism to counteract protein misfolding. ERAD disruption causes the detachment of GRP78 from transmembrane proteins, initiating a cascade involving Inositol-requiring kinase/endoribonuclease 1 (IRE1), Activating transcription factor 6 (ATF6), and Protein kinase RNA-like endoplasmic reticulum kinase (PERK) pathways. The accumulation and deposition of misfolded proteins within the cell are hallmarks of numerous neurodegenerative diseases. These aberrant proteins disrupt normal neuronal signalling and contribute to impaired cellular homeostasis, including oxidative stress and compromised protein degradation pathways. In essence, ER stress is defined as the cellular response to the accumulation of misfolded proteins in the endoplasmic reticulum, encompassing a series of signalling pathways and molecular events that aim to restore cellular homeostasis. This comprehensive review explores ER stress and its profound implications for the pathogenesis and progression of neurodegenerative diseases.

The relationship between handgrip strength and cognitive function among older adults in China: Functional limitation plays a mediating role

BACKGROUND

The deterioration of cognitive function with age has become a major public health issue. To date, the underlying mechanisms of the association between handgrip strength and cognitive function were poorly understood. This study aimed to examine the mediating effect of functional limitation in the longitudinal relationship between handgrip strength and subsequent cognitive function.

METHODS

This research recruited 4416 participants aged 60 and above from wave 2015 and 2018 of the China Longitudinal Study of Health and Retirement (CHARLS). We conducted the linear regression model and bootstrap analyses to test the mediating role of functional limitation in the relationship between handgrip strength and cognitive function.

RESULTS

After adjusting the confounders, handgrip strength was positively associated with subsequent cognitive function (β = 0.12, P < 0.001) and was negatively associated with functional limitation (β = -0.14, P < 0.001). The mediation effect of functional limitation accounted for 23.33 % of the total effect regarding the handgrip strength with cognitive function, and the magnitude of mediation effect was a*b = 0.021 (95%CI: 0.017-0.027).

LIMITATIONS

The variable of functional limitations was self-reported. And this study did not analyse the severity and duration of handgrip strength loss and functional limitations, which may lose some information.

CONCLUSIONS

Our findings revealed that handgrip strength not only directly influenced cognitive function among older individuals but also indirectly via functional limitation over 3-year follow-up. Physical exercise targeting handgrip strength and functional limitation may be an effective approach to prevent and delay cognitive decline.

The longitudinal bidirectional association between sarcopenia and cognitive function in community-dwelling older adults: Findings from the China Health and Retirement Longitudinal Study

Background

Although an association between sarcopenia and cognitive function has been demonstrated, the directional association remains unclear. The present study aimed to evaluate the longitudinal reciprocal relationship and identify the possible temporal sequence between sarcopenia and cognitive function in older Chinese adults.

Methods

Data were collected from the China Health and Retirement Longitudinal Study (CHARLS) baseline survey in 2011 and the follow-up survey in 2015. Cognitive function was measured by episodic memory and executive function. Sarcopenia status (non-sarcopenia, possible sarcopenia and sarcopenia) was defined based on the Asian Working Group for Sarcopenia 2019 criteria. Linear regression analysis and ordinal logistic regression analysis were employed to investigate the relationship between baseline sarcopenia status and follow-up cognition, as well as the association of baseline cognition with follow-up sarcopenia status, respectively. A cross-lagged panel analysis was performed to simultaneously evaluate the bidirectional association and the strength of the temporal relationship.

Results

Of 2689 participants, the median age was 65.0 years and 1249 (46.5%) were female. After adjusting for potential confounders and baseline measurements, baseline sarcopenia status was dose-dependently associated with subsequent cognitive scores (β = -0.45; P for trend = 0.001), and baseline cognitive scores (in tertiles) were also dose-dependently associated with subsequent sarcopenia status (odds ratio (OR) = 0.86; P for trend = 0.017). The cross-lagged panel analysis indicated that the standardised effect size of sarcopenia status on cognitive function (β = -0.09; P < 0.001) is larger relative to the effect of cognitive function on sarcopenia status (β = -0.05; P = 0.019).

Conclusions

There is a longitudinal, bidirectional relationship between sarcopenia status and cognitive function in older Chinese adults. Sarcopenia is likely the driving force in these dynamic associations. These findings imply that interventions in either sarcopenia or cognitive decline may have the ability to generate reciprocal benefits over time. More research is warranted to confirm these findings and to further elucidate underlying causal pathways.

Serum Biomarkers to Mild Cognitive Deficits in Children and Adolescents

Intellectual disability (ID) is a condition characterized by significant limitations in both cognitive development and adaptive behavior. The diagnosis is made through clinical assessment, standardized tests, and intelligence quotient (IQ). Genetic, inflammation, oxidative stress, and diet have been suggested to contribute to ID, and biomarkers could potentially aid in diagnosis and treatment. Study included children and adolescents aged 6-16 years. The ID group (n = 16) and the control group (n = 18) underwent the Wechsler Intelligence Scale for Children (WISC-IV) test, and blood samples were collected. Correlations between biomarker levels and WISC-IV test scores were analyzed. The ID group had an IQ score below 75, and the values of four domains (IQ, IOP, IMO, and IVP) were lower compared to the control group. Serum levels of FKN, NGF-β, and vitamin B12 were decreased in the ID group, while DCFH and nitrite levels were increased. Positive correlations were found between FKN and the QIT and IOP domains, NGF and the QIT and IMO domains, and vitamin B12 and the ICV domain. TNF-α showed a negative correlation with the ICV domain. Our study identified FKN, NGF-β, and vitamin B12 as potential biomarkers specific to ID, which could aid in the diagnosis and treatment of ID. TNF-α and oxidative stress biomarkers suggest that ID has a complex etiology, and further research is needed to better understand this condition and develop effective treatments. Future studies could explore the potential implications of these biomarkers and develop targeted interventions based on their findings.

A promising therapeutic peptide and preventive/diagnostic biomarker for age-related diseases: The Elabela/Apela/Toddler peptide

Elabela (ELA), Apela or Toddler peptide is a hormone peptide belonging to the adipokine group and a component of apelinergic system, discovered in 2013-2014. Given its high homology with apelin, the first ligand of APJ receptor, ELA likely mediates similar effects. Increasing evidence shows that ELA has a critical function not only in embryonic development, but also in adulthood, contributing to physiological and pathological conditions, such as the onset of age-related diseases (ARD). However, still little is known about the mechanisms and molecular pathways of ELA, as well as its precise functions in ARD pathophysiology. Here, we report the mechanisms by which ELA/APJ signaling acts in a very complex network of pathways for the maintenance of physiological functions of human tissue and organs, as well as in the onset of some ARD, where it appears to play a central role. Therefore, we describe the possibility to use the ELA/APJ pathway, as novel biomarker (predictive and diagnostic) and target for personalized treatments of ARD. Its potentiality as an optimal peptide candidate for therapeutic ARD treatments is largely described, also detailing potential current limitations.

One-year change in sarcopenia was associated with cognitive impairment among haemodialysis patients

BACKGROUND

Our study aimed to evaluate change in sarcopenia, its defining components over 1 year follow-up and investigate associations with subsequent cognitive decline, incident mild cognitive impairment (MCI) and dementia among patients undergoing haemodialysis (HD).

METHODS

In the multicentre, longitudinal study, 1117 HD patients aged 56.8 ± 14.3 years (654 men; and 463 women) from 17 dialysis centres in Guizhou Province, China, were recruited in 2019 and followed up for 1 year in 2020. Sarcopenia was diagnosed with Asian Working Group for Sarcopenia criteria using appendicular skeletal muscle mass index (ASMI) and handgrip strength (HGS). Body composition was measured using body composition monitor; body water, weight, and height were corrected to calculate ASMI. HGS was measured by mechanical handgrip dynamometer. Cognitive function was measured with Mini Mental State Examination. Multivariate linear, logistic regression models and subgroup analyses were employed to examine the associations of changes in sarcopenia, ASMI, and HGS with Mini Mental State Examination score change, and incident MCI, dementia.

RESULTS

Four hundred fourteen (37.1%) patients had sarcopenia at baseline; during 1 year follow-up, 257 (23.0%) developed MCI and 143 (12.8%) developed dementia. According to changes in sarcopenia, patients were stratified into four groups: non-sarcopenia; non-sarcopenia to sarcopenia; sarcopenia; and sarcopenia to non-sarcopenia. HD patients in sarcopenia and non-sarcopenia to sarcopenia groups had higher risk of MCI (34.8%, 32.0%, vs. 17.4%) and dementia (20.6%, 19.8%, vs. 8.7%), compared non-sarcopenia group (P < 0.001). Multivariate linear regression analyses showed that sarcopenia [regression coefficients (β) -1.098, 95% confidence interval (CI) -1.872, -0.324, P = 0.005] and non-sarcopenia to sarcopenia (β -1.826, -2.441, -1.212, P < 0.001) were associated with faster cognitive decline compared to non-sarcopenia. HGS decline (β 0.046, 0.027-0.064, P < 0.001) and ASMI decline (β 0.236, 0.109-0.362, P < 0.001) were both positively associated with cognitive decline. Multivariate logistic regression analyses demonstrated that patients with sarcopenia and non-sarcopenia to sarcopenia were both at increased risk of developing MCI [odds ratio (OR) 1.788, 95% CI 1.115-2.870, P = 0.016 and OR 1.589, 95% CI 1.087-2.324, P = 0.017, respectively], but only non-sarcopenia to sarcopenia was at increased risk of dementia (OR 1.792, 95% CI 1.108-2.879, P = 0.017). Both greater change of ASMI and HGS had lower risk of MCI with adjusted ORs of 0.857 (0.778-0.945, P = 0.002) and 0.976 (0.963-0.989, P < 0.001). Robust associations were found among female individuals, aged >60 years, and with low educational level.

CONCLUSIONS

Longitudinal associations were observed between new-onset, persistent sarcopenia, and cognitive impairment. Early detection and intervention should be implemented to delay the onset of sarcopenia and improve cognitive health among HD patients.

Concordant and Discordant Cerebrospinal Fluid and Plasma Cytokine and Chemokine Responses in Mild Cognitive Impairment and Early-Stage Alzheimer's Disease

Neuroinflammation may be a pathogenic mediator and biomarker of neurodegeneration at the boundary between mild cognitive impairment (MCI) and early-stage Alzheimer's disease (AD). Whether neuroinflammatory processes are endogenous to the central nervous system (CNS) or originate from systemic (peripheral blood) sources could impact strategies for therapeutic intervention. To address this issue, we measured cytokine and chemokine immunoreactivities in simultaneously obtained lumbar puncture cerebrospinal fluid (CSF) and serum samples from 39 patients including 18 with MCI or early AD and 21 normal controls using a 27-plex XMAP bead-based enzyme-linked immunosorbent assay (ELISA). The MCI/AD combined group had significant (p < 0.05 or better) or statistically trend-wise (0.05 ≤ p ≤ 0.10) concordant increases in CSF and serum IL-4, IL-5, IL-9, IL-13, and TNF-α and reductions in GM-CSF, b-FGF, IL-6, IP-10, and MCP-1; CSF-only increases in IFN-y and IL-7 and reductions in VEGF and IL-12p70; serum-only increases in IL-1β, MIP-1α, and eotaxin and reductions in G-CSF, IL-2, IL-8 and IL-15; and discordant CSF-serum responses with reduced CSF and increased serum PDGF-bb, IL-17a, and RANTES. The results demonstrate simultaneously parallel mixed but modestly greater pro-inflammatory compared to anti-inflammatory or neuroprotective responses in CSF and serum. In addition, the findings show evidence that several cytokines and chemokines are selectively altered in MCI/AD CSF, likely corresponding to distinct neuroinflammatory responses unrelated to systemic pathologies. The aggregate results suggest that early management of MCI/AD neuroinflammation should include both anti-inflammatory and pro-neuroprotective strategies to help prevent disease progression.

Non-linear relationship between dietary vitamin E intake and cognitive performance in older adults

OBJECTIVES

This study aimed to explore the relationship between dietary vitamin E (VE) intake and cognitive function in older adults.

STUDY DESIGN

This was a cross-sectional study.

METHODS

We applied data from the National Health and Nutrition Examination Survey obtained during 2011-2014 that met our requirements. The cognitive ability assessments included the Consortium to Establish a Registry for Alzheimer's Disease Word Learning (CERAD-WL) and Delayed Recall (CERAD-DR) tests, the animal fluency test, the Digit Symbol Substitution Test, and a composite z-score calculated by summing z-scores of individual tests. We used binary logistic regression analysis to explore the relationship between VE intake and cognitive performance. The results are reported using odds ratios and 95% confidence intervals. Our study also included sex-stratified analyses and sensitivity analysis. A restricted cubic splines model was used to evaluate the dose-response relationship between dietary VE intake and cognitive function.

RESULTS

This study found that a higher intake of dietary VE was associated with a lower risk of cognitive impairment in patients. Sensitivity analysis shows stable results. The results of the gender stratification analysis showed that dietary VE intake was negatively related to the risk of cognitive disorder among females. An irregular L-shaped dose-response relationship was observed between dietary VE intake and cognitive impairment risk.

CONCLUSIONS

Dietary VE intake was negatively related to the risk of cognitive disorder in older adults, with a higher VE intake lowering the risk.

Mitochondrial Bioenergetics, Redox Balance, and Calcium Homeostasis Dysfunction with Defective Ultrastructure and Quality Control in the Hippocampus of Aged Female C57BL/6J Mice

Aging is a physiological process that generates progressive decline in many cellular functions. There are many theories of aging, and one of great importance in recent years is the mitochondrial theory of aging, in which mitochondrial dysfunction that occurs at advanced age could be responsible for the aged phenotype. In this context, there is diverse information about mitochondrial dysfunction in aging, in different models and different organs. Specifically, in the brain, different studies have shown mitochondrial dysfunction mainly in the cortex; however, until now, no study has shown all the defects in hippocampal mitochondria in aged female C57BL/6J mice. We performed a complete analysis of mitochondrial function in 3-month-old and 20-month-old (mo) female C57BL/6J mice, specifically in the hippocampus of these animals. We observed an impairment in bioenergetic function, indicated by a decrease in mitochondrial membrane potential, O2 consumption, and mitochondrial ATP production. Additionally, there was an increase in ROS production in the aged hippocampus, leading to the activation of antioxidant signaling, specifically the Nrf2 pathway. It was also observed that aged animals had deregulation of calcium homeostasis, with more sensitive mitochondria to calcium overload and deregulation of proteins related to mitochondrial dynamics and quality control processes. Finally, we observed a decrease in mitochondrial biogenesis with a decrease in mitochondrial mass and deregulation of mitophagy. These results show that during the aging process, damaged mitochondria accumulate, which could contribute to or be responsible for the aging phenotype and age-related disabilities.

Associations between glutamic acid decarboxylase antibodies, oxidative stress markers, and cognitive capacity in adolescents who stutter

In this study, we amid to evaluate the correlation between the change in the expressed levels of anti-GAD antibodies titers, oxidative stress markers, cytokines markers, and cognitive capacity in adolescents with mild stuttering. Eighty participants (60 male/20 female) with the age range of 10-18 years with moderate stutteringparticipated in this study. To assess the stuttering and cognitive function, stutteringseverity instrument (SSI-4; 4th edit.)and the LOTCA-7 scores assessment were applied respectively in all subjects. In addition, serum GAD antibodies, cytokines like TNF-α, CRP,and IL-6 withtotal antioxidant capacity and nitric oxide as oxidative stress markers were estimated using calorimetry and immunoassay techniques.The results showed that good cognitive capacity was reported in about 56.25 % of the study population (n = 45) with a 117.52 ± 6.3 mean LOTCA-7 score. However, abnormal cognitive function was identified in 43.75 % of the study population (n = 35); they were categorized into moderate (score 62-92, n = 35), and poor (score 31-62; n = 10). There were significant associations between cognitive capacity reported and all biomarkers. The expression of GAD antibodies is significantly associated with the degree of cognitive capacity among students with stuttering. Significant association with the reduction (P = 0.01) in LOTCA-7 score domains, particularly orientation, thinking operations, attention, and concentration among students with variable cognitive capacity compared to controls. In addition, the expressed higher GAD antibodies in students with moderate and poor cognitive capacity showed to be significantly correlated with both elevated concentrations of cytokines; TNF-α, CRP, and IL-6, and the reduction of TAC and nitric oxide (NO) respectively. This study concludes that abnormality of cognitive capacity showed to be associated with higher expression of GAD antibodies, cytokines, and oxidative stress in school students with moderate stuttering.

Association between sarcopenia and cognitive function in older Chinese adults: Evidence from the China health and retirement longitudinal study

Background

Sarcopenia and cognitive impairment are the most common causes of disability in the aging population. The potential role of sarcopenia in the development of cognitive impairment remains poorly understood. A cross-sectional analysis was performed using nationally representative data to evaluate associations between sarcopenia and cognition in China.

Methods

We included 2,391 participants (35.63% female) who were at least 60 years of age in 2015 from the China Health and Retirement Longitudinal Study (CHARLS). Muscle strength, appendicular skeletal mass (ASM), and physical performance measurements, were measured to diagnose sarcopenia according to the Asian Working Group for Sarcopenia 2019 (AWGS2019). Cognitive function was assessed by 10 items in the Telephone Interview for Cognitive Status (TICS-10), delayed word recall, and graph drawing. Based on cognitive score tertiles, data were divided into three groups. Multiple linear and logistic regression models were used to assess the relationship between sarcopenia and cognition.

Results

The prevalence of possible sarcopenia was 27.16% for men and 27.46% for women. Cognitive decline was significantly associated with sarcopenia status (β = -0.88, p < 0.001) and negatively associated with components of sarcopenia in male group. The results remained consistent in male after further adjusting for creatinine, uric acid, blood sugar, etc. Low cognitive function in female was only associated with low muscle strength (β = -0.85, p = 0.02). In addition, participants with possible sarcopenia had greater risk of cognitive decline than those without sarcopenia (OR = 1.41; 95% CI: 1.06-1.87). However, the same association was not significant in female group.

Conclusion

We suggest that sarcopenia might be associated with cognition function, with possible sarcopenia being significantly associated with higher cognition risk in China population, which providing a further rationale for timely recognition and management of sarcopenia.

Associations between dietary and blood inflammatory indices and their effects on cognitive function in elderly Americans

Objective

To determine the correlations between dietary and blood inflammation indices in elderly Americans and their effects on cognitive function.

Methods

This research extracted data from the 2011-2014 National Health and Nutrition Examination Survey for 2,479 patients who were ≥60 years old. Cognitive function was assessed as a composite cognitive function score (Z-score) calculated from the results of the Consortium to Establish a Registry for Alzheimer's Disease Word Learning and Delayed Recall tests, the Animal Fluency test, and the Digit Symbol Substitution Test. We used a dietary inflammatory index (DII) calculated from 28 food components to represent the dietary inflammation profile. Blood inflammation indicators included the white blood cell count (WBC), neutrophil count (NE), lymphocyte count (Lym), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), neutrophil-albumin ratio (NAR), systemic immune-inflammation index [SII, calculated as (peripheral platelet count) × NE/Lym], and systemic inflammatory response index [SIRI, calculated as (monocyte count) × NE/Lym]. WBC, NE, Lym, NLR, PLR, NAR, SII, SIRI, and DII were initially treated as continuous variables. For logistic regression, WBC, NE, Lym, NLR, PLR, NAR, SII, and SIRI were divided into quartile groups, and DII was divided into tertile groups.

Results

After adjusting for covariates, WBC, NE, NLR, NAR, SII, SIRI, and DII scores were markedly higher in the cognitively impaired group than in the normal group (p < 0.05). DII was negatively correlated with the Z-score when combined with WBC, NE, and NAR (p < 0.05). After adjusting for all covariates, DII was positively correlated with SII in people with cognitive impairment (p < 0.05). Higher DII with NLR, NAR, SII, and SIRI all increased the risk of cognitive impairment (p < 0.05).

Conclusion

DII was positively correlated with blood inflammation indicators, and higher DII and blood inflammation indicators increased the risk of developing cognitive impairment.

Copper-containing nanoparticles: Mechanism of antimicrobial effect and application in dentistry-a narrative review

Copper has been used as an antimicrobial agent long time ago. Nowadays, copper-containing nanoparticles (NPs) with antimicrobial properties have been widely used in all aspects of our daily life. Copper-containing NPs may also be incorporated or coated on the surface of dental materials to inhibit oral pathogenic microorganisms. This review aims to detail copper-containing NPs' antimicrobial mechanism, cytotoxic effect and their application in dentistry.

Jatamansinol from Nardostachys jatamansi Ameliorates Tau-Induced Neurotoxicity in Drosophila Alzheimer's Disease Model

Nardostachys jatamansi has long been used to prepare Medhya Rasayana in traditional Indian Ayurveda medicine to treat neurological disorders and enhance memory. Jatamansinol from the N. jatamansi against Alzheimer's disease (AD) showed that it could be a multitargeted drug against AD. Drosophila is an ideal model organism for studying a progressive age-related neurodegenerative disease such as AD since its neuronal organizations and functioning are highly similar to that of humans. The current study investigates the neuroprotective properties of jatamansinol against Tau-induced neurotoxicity in the AD Drosophila model. Results indicate jatamansinol is not an antifeedant for larva and adult Drosophila. Lifespan, locomotor activity, learning and memory, Tau protein expression level, eye degeneration, oxidative stress level, and cholinesterase activities were analyzed in 10, 20, and 30-day-old control (wild type), and tauopathy flies reared on jatamansinol supplemented food or regular food without jatamansinol supplementation. Jatamansinol treatment significantly extends the lifespan, improves locomotor activity, enhances learning and memory, and reduces Tau protein levels in tauopathy flies. It boosts the antioxidant enzyme activities, prevents Tau-induced oxidative stress, ameliorates eye degeneration, and inhibits cholinesterase activities in Tau-induced AD model. This study provides the first evidence that jatamansinol protects against Tau's neurotoxic effect in the AD Drosophila model, and it can be a potential therapeutic drug candidate for AD.

A Fluorine-19 Magnetic Resonance Probe, Shiga-Y5, Downregulates Thioredoxin-Interacting Protein Expression in the Brain of a Mouse Model of Alzheimer's Disease

Thioredoxin-interacting protein (TXNIP) is involved in multiple disease-associated functions related to oxidative stress, especially by inhibiting the anti-oxidant- and thiol-reducing activity of thioredoxin (TXN). Shiga-Y5 (SY5), a fluorine-19 magnetic resonance probe for detecting amyloid-β deposition in the brain, previously showed therapeutic effects in a mouse model of Alzheimer's disease; however, the mechanism of action of SY5 remains unclear. SY5 passes the blood-brain barrier and then undergoes hydrolysis to produce a derivative, Shiga-Y6 (SY6), which is a TXNIP-negative regulator. Therefore, this study investigates the therapeutic role of SY5 as the prodrug of SY6 in the thioredoxin system in the brain of a mouse model of Alzheimer's disease. The intraperitoneal injection of SY5 significantly inhibited TXNIP mRNA (p = 0.0072) and protein expression (p = 0.0143) induced in the brain of APP/PS1 mice. In contrast, the levels of TXN mRNA (p = 0.0285) and protein (p = 0.0039) in the brain of APP/PS1 mice were increased after the injection of SY5. The ratio of TXN to TXNIP, which was decreased (p = 0.0131) in the brain of APP/PS1 mice, was significantly increased (p = 0.0072) after the injection of SY5. These results suggest that SY5 acts as a prodrug of SY6 in targeting the thioredoxin system and could be a potential therapeutic compound in oxidative stress-related diseases in the brain.

Effects of Low-Intensity Transcranial Pulsed Ultrasound Treatment in a Model of Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease. One of the main pathology markers of AD is the beta-amyloid plaques (βA_1-42) created from residues of the badly processed amyloid precursor protein. The accumulation of these plaques can induce neuroinflammation and oxidative stress and impair antioxidant mechanisms, culminating in cognitive and memory deficits. New therapies are necessary to treat AD as the approved drugs do not treat the progress of the disease. Transcranial low-intensity pulsed ultrasound (LIPUS) affects brain metabolism and could be tested as a treatment for AD. This study was aimed at evaluating the LIPUS treatment in a model of AD induced by βA_1-42 intracerebroventricularly (ICV) and its effects on learning memory, neurotrophins, neuroinflammation and oxidative status. βA_1-42 was administered ICV 24 h before the start of a 5-wk LIPUS treatment. The treatment with LIPUS improved recognition memory, as well as increasing nerve growth factor β and brain-derived neurotrophic factor levels in the hippocampus and cortex. There was a decrease in protein damage in the hippocampus treated with LIPUS. Neuroinflammation and oxidative stress were not present in the AD model used. The results indicated that LIPUS is a novel and promising adjuvant strategy for treatment of the late stage of AD.

Associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults

This study examined the associations between vitamin E, oxidative stress markers, total homocysteine levels, and physical activity or cognitive capacity in older adults. One hundred and six older adults (62 men, 44 women) within the age range of 56-81 years participated. The Global Physical Activity Questionnaire and the Loewenstein Occupational Therapy Cognitive Assessment were used to assess physical activity and cognitive function, respectively. Vitamin E (e.g., α-tocopherol and γ-tocopherol), oxidative stress markers (e.g., total antioxidant capacity and nitric oxide), and total homocysteine were estimated. There were significant associations between physical activity (high versus moderate versus poor) and all biomarkers (all p = 0.000, and p = 0.010 for γ-tocopherol). While total homocysteine and total antioxidant capacity were significantly associated with cognitive capacity (p = 0.000), vitamin E levels (e.g., α-tocopherol and γ-tocopherol) and nitric oxide (p = 0.354, 0.103 and 0.060, respectively) were not related to cognitive capacity in older adults. This study concludes that physical activity was associated with Vitamin E, oxidative stress markers, total homocysteine, and cognitive capacity in older adults. Although cognitive capacity was associated with total homocysteine and total antioxidant capacity, it was unrelated to vitamin E levels and nitric oxide in older adults.

mTOR in Alzheimer disease and its earlier stages: Links to oxidative damage in the progression of this dementing disorder

Alzheimer's disease (AD) is the most prevalent form of dementia in the elderly population and has worldwide impact. The etiology of the disease is complex and results from the confluence of multiple mechanisms ultimately leading to neuronal loss and cognitive decline. Among risk factors, aging is the most relevant and accounts for several pathogenic events that contribute to disease-specific toxic mechanisms. Accumulating evidence linked the alterations of the mammalian target of rapamycin (mTOR), a serine/threonine protein kinase playing a key role in the regulation of protein synthesis and degradation, to age-dependent cognitive decline and pathogenesis of AD. To date, growing studies demonstrated that aberrant mTOR signaling in the brain affects several pathways involved in energy metabolism, cell growth, mitochondrial function and proteostasis. Recent advances associated alterations of the mTOR pathway with the increased oxidative stress. Disruption of all these events strongly contribute to age-related cognitive decline including AD. The current review discusses the main regulatory roles of mTOR signaling network in the brain, focusing on its role in autophagy, oxidative stress and energy metabolism. Collectively, experimental data suggest that targeting mTOR in the CNS can be a valuable strategy to prevent/slow the progression of AD.

Physical Exercise Training Improves Judgment and Problem-Solving and Modulates Serum Biomarkers in Patients with Alzheimer's Disease

Alzheimer's disease (AD) is characterized by progressive impairment of memory, with an etiology involving oxidative stress and inflammation. Exercise training is a safe, efficacious, and economic approach to manage neurodegenerative diseases. In AD, the biomarkers of oxidative damage to lipids, proteins, and DNA are elevated. In the present study, we aimed to evaluate whether exercise is effective in patients with AD by assessing the serum biomarkers associated with the redox status, neurotrophin levels, and inflammatory system. This nonrandomized clinical study (n = 15) involved 22 training sessions performed twice a week (60 min/session) in patients diagnosed with AD. The cognitive and self-awareness tests were performed 48 h before and after the physical training session. In patients with AD, physical training significantly improved the judgment and problem-solving domains of the memory score; however, general mental health, memory, orientation, and home/hobby domains were improved slightly, and the neurotrophin levels remained unaltered. Significantly, the markers of protein integrity also increased following exercise. Furthermore, catalase activity and ROS levels decreased, nitrite levels increased, and interleukin-4 level increased following physical training in patients with AD. Although proinflammatory cytokines remained unaltered, the levels of neuron-specific enolase, a marker of neuronal damage, decreased following exercise training in these patients. In conclusion, physical exercise training could be a safe and effective method for blocking the AD progression and improving the antioxidant capacity and anti-inflammatory system, whereas certain assessed biomarkers could be utilized to monitor AD therapy.

Associations of sarcopenia and its defining components with cognitive function in community-dwelling oldest old

BACKGROUND

This study aimed to investigate the associations of sarcopenia and its defining components with cognitive function in community-dwelling oldest old (over 80 years old) in China.

METHODS

Sarcopenia was diagnosed by the 2019 Asian Working Group for Sarcopenia (AWGS) criteria. Cognitive function was evaluated by the Montreal Cognitive Assessment (MoCA). Logistic and linear regression models were used to explore the associations of sarcopenia and its defining components with risk of mild cognitive impairment (MCI), and performance on multiple cognitive domains among 428 adults aged 80 years and older.

RESULTS

The overall prevalence of sarcopenia was 35.5%, with 40.34% for men and 32.14% for women. The prevalence of MCI was higher among sarcopenic oldest old than non-sarcopenic oldest old (28.95% vs. 17.39%, p = 0.005). Multivariate logistic regression analyses showed that sarcopenia [odds ratio (OR) = 1.86, 95% confidence interval (CI): 1.04-3.33], low handgrip strength (HS) [OR = 2.33, 95% CI: 1.40-3.87] and slow gait speed (GS) [OR = 2.31, 95% CI: 1.13-4.72] were significantly and independently associated with risk of MCI. Multivariate linear regression analyses showed that low HS was associated with worse performance in global cognitive function, visuospatial and executive function, naming and delayed recall.

CONCLUSIONS

Sarcopenia, low HS and low GS was significantly associated with MCI in community-dwelling oldest old. The associations between sarcopenia and its defining components with different cognitive subdomains could be further explored in the future.

The Diagnostic Potential of Amyloidogenic Proteins

Neurodegenerative disorders are a highly prevalent class of diseases, whose pathological mechanisms start before the appearance of any clear symptoms. This fact has prompted scientists to search for biomarkers that could aid early treatment. These currently incurable pathologies share the presence of aberrant aggregates called amyloids in the nervous system, which are composed of specific proteins. In this review, we discuss how these proteins, their conformations and modifications could be exploited as biomarkers for diagnostic purposes. We focus on proteins that are associated with the most prevalent neurodegenerative disorders, including Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, and frontotemporal dementia. We also describe current challenges in detection, the most recent techniques with diagnostic potentials and possible future developments in diagnosis.

Roflumilast and tadalafil improve learning and memory deficits in intracerebroventricular Aβ1-42 rat model of Alzheimer's disease through modulations of hippocampal cAMP/cGMP/BDNF signaling pathway

BACKGROUND

Alzheimer's disease (AD) is the most prevalent age-dependent neurodegenerative disease characterized by progressive impairment of memory and cognitive functions. Cyclic nucleotides like cAMP and cGMP are well-known to play an important role in learning and memory functions. Enhancement of cAMP and cGMP levels in the hippocampus by phosphodiesterase (PDE) inhibitors might be a novel therapeutic approach for AD. Thus, the present study was planned to explore the therapeutic potential of roflumilast (RFM) and tadalafil (TDF) phosphodiesterase inhibitors in intracerebroventricular (ICV) Aβ1-42 induced AD in rats.

METHODS

ICV Aβ1-42 was administered in rats followed by treatment with RFM (0.05 mg/kg) and TDF (0.51 mg/kg) for 15 days. Novel object recognition (NOR), and Morris water maze (MWM) test were performed during the drug treatment schedule. On the day, 22 rats were sacrificed, and hippocampus was separated for biochemical, neuroinflammation, and histopathological analysis.

RESULTS

Aβ1-42 infused rats were induce behavioral impairment and increased AChE, BACE-1, Aβ1-42, GSK-3β, phosphorylated tau (p-Tau), pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) levels, oxidative stress (increased MDA, Nitrite and decreased GSH), histopathological changes, and reduced cAMP, cGMP, and BDNF levels. RFM and TDF significantly attenuated Aβ1-42 induced memory deficits and neuropathological alterations in the hippocampus.

CONCLUSION

The outcomes of the current study indicate that RFM and TDF lead to memory enhancement through upregulation of cAMP/cGMP/BDNF pathway, thus they may have a therapeutic potential in cognitive deficits associated with AD.

Palm Fruit Bioactive Complex (PFBc), a Source of Polyphenols, Demonstrates Potential Benefits for Inflammaging and Related Cognitive Function

Cognitive function is a key aspect of healthy aging. Inflammation associated with normal aging, also called inflammaging is a primary risk factor for cognitive decline. A diet high in fruits and vegetable and lower in calories, particularly a Mediterranean Diet, may lower the risk of age-related cognitive decline due in part to the associated high intake of antioxidants and polyphenols. A phenolic, Palm Fruit Bioactive complex (PFBc) derived from the extraction process of palm oil from oil palm fruit (Elaeis guineensis), is reported to offset inflammation due to its high antioxidant, especially vitamin E, and polyphenol content. The benefit is thought to be achieved via the influence of antioxidants on gene expression. It is the purpose of this comprehensive review to discuss the etiology, including gene expression, of mild cognitive impairment (MCI) specific to dietary intake of antioxidants and polyphenols and to focus on the potential impact of nutritional interventions specifically PFBc has on MCI. Several in vitro, in vivo and animal studies support multiple benefits of PFBc especially for improving cognitive function via anti-inflammatory and antioxidant mechanisms. While more human studies are needed, those completed thus far support the benefit of consuming PFBc to enhance cognitive function via its anti-inflammatory antioxidant functions.

Nutrition status mediates the association between cognitive decline and sarcopenia

In this study, we investigated whether nutrition status mediates the relationship between cognitive decline and sarcopenia. Sarcopenia was assessed in 4023 community-dwelling older adults from West China using the AWGS 2014 diagnostic criteria. Cognitive function and nutrition status were assessed using the 10-item Short Portable Mental Status Questionnaire (SPMSQ) and Mini Nutrition Assessment-Short Form (MNA-SF) scale, respectively. Mediation model regression analysis demonstrated that nutrition status was negatively associated with sarcopenia (β = -0.521; 95% CI: -0.583 to -0.459). The indirect effects of cognitive decline on sarcopenia were significant after adjusting for age, sex, and ethnicity (β = 0.015; 95% CI: 0.012 to 0.017), but the direct effects of cognitive decline on sarcopenia were not statistically significant after adding nutrition status as a parameter in the mediation model analysis (β = -0.001; 95% CI: -0.008 to 0.005). Structural equation model (SEM) framework pathway analysis confirmed the association between nutrition status, cognitive decline, and sarcopenia. These findings demonstrate that the negative effects of cognitive decline on sarcopenia were mediated by nutrition status. We therefore postulate that maintaining a good nutrition status delays the negative effects of cognitive decline on sarcopenia in older adults.

Glutathione Serum Levels and Rate of Multimorbidity Development in Older Adults

We aimed to investigate the association between baseline levels of total serum glutathione (tGSH) and rate of chronic disease accumulation over time. The study population (n = 2,596) was derived from a population-based longitudinal study on ≥60-year-olds living in Stockholm. Participants were clinically assessed at baseline, 3- and 6-year follow-ups. Multimorbidity was measured as the number of chronic conditions from a previously built list of 60 diseases. Linear mixed models were applied to analyze the association between baseline tGSH levels and the rate of multimorbidity development over 6 years. We found that at baseline, participants with ≥4 diseases had lower tGSH levels than participants with no chronic conditions (3.3 vs 3.6 µmol/L; p < .001). At follow-up, baseline levels of tGSH were inversely associated with the rate of multimorbidity development (β * time: -0.044, p < .001) after adjusting for age, sex, education, levels of serum creatinine, C-reactive protein, albumin, body mass index, smoking, and time of dropout or death. In conclusion, serum levels of tGSH are inversely associated with multimorbidity development; the association exists above and beyond the link between tGSH and specific chronic conditions. Our findings support the hypothesis that tGSH is a biomarker of multisystem dysregulation that eventually leads to multimorbidity.

Molecular Mechanisms and Genetics of Oxidative Stress in Alzheimer's Disease

Alzheimer’s disease is the most common neurodegenerative disorder that can cause dementia in elderly over 60 years of age. One of the disease hallmarks is oxidative stress which interconnects with other processes such as amyloid-β deposition, tau hyperphosphorylation, and tangle formation. This review discusses current thoughts on molecular mechanisms that may relate oxidative stress to Alzheimer’s disease and identifies genetic factors observed from in vitro, in vivo, and clinical studies that may be associated with Alzheimer’s disease-related oxidative stress.

Modulation of Proteome Profile in AβPP/PS1 Mice Hippocampus, Medial Prefrontal Cortex, and Striatum by Palm Oil Derived Tocotrienol-Rich Fraction

Tocotrienol-rich fraction (TRF) is a mixture of vitamin E analogs derived from palm oil. We previously demonstrated that supplementation with TRF improved cognitive function and modulated amyloid pathology in AβPP/PS1 mice brains. The current study was designed to examine proteomic profiles underlying the therapeutic effect of TRF in the brain. Proteomic analyses were performed on samples of hippocampus, medial prefrontal cortex (mPFC), and striatum using liquid chromatography coupled to Q Exactive HF Orbitrap mass spectrometry. From these analyses, we profiled a total of 5,847 proteins of which 155 proteins were differentially expressed between AβPP/PS1 and wild-type mice. TRF supplementation of these mice altered the expression of 255 proteins in the hippocampus, mPFC, and striatum. TRF also negatively modulated the expression of amyloid beta A4 protein and receptor-type tyrosine-protein phosphatase alpha protein in the hippocampus. The expression of proteins in metabolic pathways, oxidative phosphorylation, and those involved in Alzheimer’s disease were altered in the brains of AβPP/PS1 mice that received TRF supplementation.

Incident Impaired Cognitive Function in Sarcopenic Obesity: Data From the National Health and Aging Trends Survey

Objectives

The prevalence of obesity with sarcopenia is increasing in adults aged ≥65 years. This geriatric syndrome places individuals at risk for synergistic complications that leads to long-term functional decline. We ascertained the relationship between sarcopenic obesity and incident long-term impaired global cognitive function in a representative US population.

Design

A longitudinal, secondary data set analysis using the National Health and Aging Trends Survey.

Setting

Community-based older adults in the United States.

Participants

Participants without baseline impaired cognitive function aged ≥65 years with grip strength and body mass index measures.

Methods

Sarcopenia was defined using the Foundation for the National Institutes of Health Sarcopenia Project grip strength cut points (men <35.5 kg; women <20 kg), and obesity was defined using standard body mass index (BMI) categories. Impaired global cognition was identified as impairment in the Alzheimer's Disease-8 score or immediate/delayed recall, orientation, clock-draw test, date/person recall. Proportional hazard models ascertained the risk of impaired cognitive function over 8 years (referent = neither obesity or sarcopenia).

Results

Of the 5822 participants (55.7% women), median age category was 75 to 80, and mean grip strength and BMI were 26.4 kg and 27.5 kg/m², respectively. Baseline prevalence of sarcopenic obesity was 12.9%, with an observed subset of 21.2% participants having impaired cognitive function at follow-up. Compared with those without sarcopenia or obesity, the risk of impaired cognitive function was no different in obesity alone [hazard ratio (HR) 0.98; 95% confidence interval (CI) 0.82-1.16]), but was significantly higher in sarcopenia (HR 1.60; 95% CI 1.42-1.80) and sarcopenic obesity (HR 1.20; 95% CI 1.03-1.40). There was no significant interaction term between sarcopenia and obesity.

Conclusions

Both sarcopenia and sarcopenic obesity are associated with an increased long-term risk of impaired cognitive function in older adults.

Biological and Functional Biomarkers of Aging: Definition, Characteristics, and How They Can Impact Everyday Cancer Treatment

Purpose of Review

Recognize which are the elements that predict why a person is aging faster or slower and which intervention we can arrange to slow down the process, which permits to prevent or delay the progression of multimorbidity and disability.

Recent Findings

Aging is a complex process that leads to changes in all the systems of the body and all the functions of the person; however, aging develops at different rates in different people, and chronological age is not always consistent with biological age.

Summary

Gerontologists are focused not only on finding the best theory able to explain aging but also on identifying one or more markers, which are able to describe aging processes. These biomarkers are necessary to better define the aging-related pathologies, manage multimorbidity, and improve the quality of life. The aim of this paper is to review the most recent evidence on aging biomarkers and the clusters related to them for personalization of treatments.

Metallotexaphyrins as MRI-Active Catalytic Antioxidants for Neurodegenerative Disease: A Study on Alzheimer's Disease

The complex etiology of neurodegeneration continues to stifle efforts to develop effective therapeutics. New agents elucidating key pathways causing neurodegeneration might serve to increase our understanding and potentially lead to improved treatments. Here, we demonstrate that a water-soluble manganese(II) texaphyrin (MMn) is a suitable magnetic resonance imaging (MRI) contrast agent for detecting larger amyloid beta constructs. The imaging potential of MMn was inferred on the basis of in vitro studies and in vivo detection in Alzheimer's disease C. elegans models via MRI and ICP-MS. In vitro antioxidant- and cellular-based assays provide support for the notion that this porphyrin analog shows promise as a therapeutic agent able to mitigate the oxidative and nitrative toxic effects considered causal in neurodegeneration. The present report marks the first elaboration of an MRI-active metalloantioxidant that confers diagnostic and therapeutic benefit in Alzheimer's disease models without conjugation of a radioisotope, targeting moiety, or therapeutic payload.

Vitamin E and Alzheimer's disease: the mediating role of cellular aging

BACKGROUND

Vitamin E represents a potent antioxidant and anti-inflammatory system, playing a role in Alzheimer's disease (AD). Different plasma concentrations of the forms of vitamin E are observed in AD compared to cognitively healthy subjects.

AIM

Since these modifications may modulate the markers of oxidative stress and cellular aging, we aim to explore the relationship between vitamin E forms and leukocyte telomere length (LTL) in AD.

METHODS

53 AD subjects and 40 cognitively healthy controls (CTs) were enrolled. The vitamin E forms (α-, β-, γ- and δ-tocopherol, α-, β-, γ- and δ-tocotrienol), the ratio of α-tocopherylquinone/α-tocopherol and 5-nitro-γ-tocopherol/γ-tocopherol (markers of oxidative/nitrosative damage) and LTL were measured.

RESULTS AND DISCUSSION

Regression model was used to explore the associations of vitamin E forms and LTL with AD. The interaction of LTL in the association between vitamin E forms and AD was tested. AD subjects showed significantly lower concentrations of α-, β-, γ- and δ-tocopherol, α- and δ-tocotrienol, total tocopherols, total tocotrienols and total vitamin E compared to CTs. AD subjects showed higher values of nitrosative/oxidative damage. The adjusted analyses confirmed a significant relationship of AD with plasma concentrations of α- and β-tocopherols, δ-tocotrienol, total tocopherols, total tocotrienol, total vitamin E and oxidative/nitrosative damage. However, nitrosative damage was significantly associated with AD only in subjects with higher LTL and not in those expressing marked cellular aging.

CONCLUSIONS

Our study confirms the role of vitamin E in AD pathology and indicates that nitrosative damage influences the association with AD only in subjects characterized by longer LTL.

Prevalence of sarcopenia in multi ethnics adults and the association with cognitive impairment: findings from West-China health and aging trend study

Background

Sarcopenia is a condition that is characterized by loss of muscle mass, muscle strength and muscle functional impairment with ageing. It is associated with poor health outcomes, premature death and a significant burden on the global health economy. The prevalence of sarcopenia in China is unknown since most of the studies are lack of uniform standard. The study was undertaken to study the prevalence of sarcopenia and the association with cognitive impairment among multi-ethnic adults aged 50 years old or older in western China.

Methods

We measured gait speed, handgrip strength and muscle mass by using bioelectrical impedance analysis (BIA) for all eligible participants and 4500 participants were eligible for the analysis. We defined sarcopenia using the diagnostic algorithm recommended by the Asian Working Group for Sarcopenia (AWGS). We assessed the participants’ cognitive functions using the 10-item Short Portable Mental Status Questionnaire (SPMSQ). Relationships between sarcopenia and cognitive impairment were analyzed using univariate and multivariate analyses.

Results

Of 4500 participants (mean age 62.4 ± 8.3 years), 869 (19.31%) adults were sarcopenia. 446 (9.9%) participants were identified as having mild cognitive impairment, 144 (3.2%) adults were identified as having moderate/severe cognitive impairment. After adjusting for age, gender, ethnics and other potential cofounders, cognitive impairment was found to be independently associated with sarcopenia with a dosage effect (mild cognitive impairment: odds ratio [OR]: 1.41, 95% CI 1.10–1.82; moderate/severe cognitive impairment: OR: 3.05, 95% CI 2.08–4.49). After gender stratification, the association between mild cognitive impairment with sarcopenia in male is not significant, while is still significant in female. While the association between moderate/severe cognitive impairment is independently associated with sarcopenia in both male and female.

Conclusions

The prevalence rates of sarcopenia, mild cognitive impairment, moderate/severe cognitive impairment among the communities aged 50 or older in western China were 19.31, 9.9 and 3.2%, respectively. Cognitive impairment was significantly associated with sarcopenia with a dosage effect, especially in female.

2-Amino-3'-dialkylaminobiphenyl-based fluorescent intracellular probes for nitric oxide surrogate N2O3

Fluorescent probes for nitric oxide (NO), or more frequently for its oxidized surrogate dinitrogen trioxide (N2O3), have enabled scientists to study the contributions of this signaling molecule to many physiological processes. Seeking to improve upon limitations of other probes, we have developed a family of fluorescent probes based on a 2-amino-3'-dialkylaminobiphenyl core. This core condenses with N2O3 to form benzo[c]cinnoline structures, incorporating the analyte into the newly formed fluorophore, which results in product fluorescence with virtually no background contribution from the initial probe. We varied the substituents in the core in order to optimize both the reactivity of the probes with N2O3 and their cinnoline products' fluorescence wavelengths and brightness. The top candidates were then applied to cultured cells to verify that they could respond to NO within cellular milieus, and the top performer, NO530, was compared with a "gold standard" commercial probe, DAF-FM, in a macrophage-derived cell line, RAW 264.7, stimulated to produce NO. NO530 demonstrated similar or better sensitivity and higher selectivity for NO than DAF, making it an attractive potential alternative for NO tracking in various applications.

Nrf2/ARE Pathway Modulation by Dietary Energy Regulation in Neurological Disorders

Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates the expression of an array of enzymes with important detoxifying and antioxidant functions. Current findings support the role of high levels of oxidative stress in the pathogenesis of neurological disorders. Given the central role played by Nrf2 in counteracting oxidative damage, a number of studies have targeted the modulation of this transcription factor in order to confer neuroprotection. Nrf2 activity is tightly regulated by oxidative stress and energy-based stimuli. Thus, many dietary interventions based on energy intake regulation, such as dietary energy restriction (DER) or high-fat diet (HFD), modulate Nrf2 with consequences for a variety of cellular processes that affect brain health. DER, by either restricting calorie intake or meal frequency, activates Nrf2 thereby triggering its protective effects, whilst HFD inhibit this pathway, thereby exacerbating oxidative stress. Consequently, DER protocols can be valuable strategies in the management of central nervous system (CNS) disorders. Herein, we review current knowledge of the role of Nrf2 signaling in neurological diseases, namely Alzheimer’s disease, Parkinson’s disease, multiple sclerosis and cerebral ischemia, as well as the potential of energy intake regulation in the management of Nrf2 signaling.

The Full Spectrum of Alzheimer's Disease Is Rooted in Metabolic Derangements That Drive Type 3 Diabetes

The standard practice in neuropathology is to diagnose Alzheimer's disease (AD) based on the distribution and abundance of neurofibrillary tangles and Aβ deposits. However, other significant abnormalities including neuroinflammation, gliosis, white matter degeneration, non-Aβ microvascular disease, and insulin-related metabolic dysfunction require further study to understand how they could be targeted to more effectively remediate AD. This review addresses non-Aβ and non-pTau AD-associated pathologies, highlighting their major features, roles in neurodegeneration, and etiopathic links to deficits in brain insulin and insulin-like growth factor signaling and cognitive impairment. The discussion delineates why AD with its most characteristic clinical and pathological phenotypic profiles should be regarded as a brain form of diabetes, i.e., type 3 diabetes, and entertains the hypothesis that type 3 diabetes is just one of the categories of insulin resistance diseases that can occur independently or overlap with one or more of the others, including type 2 diabetes, metabolic syndrome, and nonalcoholic fatty liver disease.

Protein nitration profile of CD3+ lymphocytes from Alzheimer disease patients: Novel hints on immunosenescence and biomarker detection

Alzheimer's disease (AD) is a progressive form of dementia characterized by increased production of amyloid-β plaques and hyperphosphorylated tau protein, mitochondrial dysfunction, elevated oxidative stress, reduced protein clearance, among other. Several studies showed systemic modifications of immune and inflammatory systems due, in part, to decreased levels of CD3⁺ lymphocytes in peripheral blood in AD. Considering that oxidative stress, both in the brain and in the periphery, can influence the activation and differentiation of T-cells, we investigated the 3-nitrotyrosine (3-NT) proteome of blood T-cells derived from AD patients compared to non-demented (ND) subjects by using a proteomic approach. 3-NT is a formal protein oxidation and index of nitrosative stress. We identified ten proteins showing increasing levels of 3-NT in CD3⁺ T-cells from AD patients compared with ND subjects. These proteins are involved in energy metabolism, cytoskeletal structure, intracellular signaling, protein folding and turnover, and antioxidant response and provide new insights into the molecular mechanism that impact reduced T-cell differentiation in AD. Our results highlight the role of peripheral oxidative stress in T-cells related to immune-senescence during AD pathology focusing on the specific targets of protein nitration that conceivably can be suitable to further therapies. Further, our data demonstrate common targets of protein nitration between the brain and the periphery, supporting their significance as disease biomarkers.

Activation of Nrf2/ARE pathway alleviates the cognitive deficits in PS1V97L-Tg mouse model of Alzheimer's disease through modulation of oxidative stress

Oxidative stress refers to an imbalance between oxidative and antioxidative systems due to environmental factors. Although oxidative stress is implicated in the pathogenesis of Alzheimer's disease (AD), its precise role is not yet understood. We aimed to investigate the pathogenic mechanisms of the oxidative stress by using in vitro cultured neurons and in vivo AD models of PS1V97L-transgenic (Tg) mice. Our results showed that when oxidative stress became increasingly evident, the endogenous protective pathway of nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) decreased in 10-month-old PS1V97L-Tg mice. Activating the Nrf2/ARE pathway suppressed oxidative stress, decreased amyloid-β (Aβ), and improved the cognitive function of the PS1V97L-Tg mice. In contrast, blocking the Nrf2/ARE pathway augmented oxidative injury and decreased the cell viability of PS1V97L-Tg neurons. Our results highlight the role of the Nrf2/ARE pathway in regulating oxidative stress of the PS1V97L-Tg mice and may indicate a potential therapeutic avenue for AD treatment.

Association among handgrip strength, body mass index and decline in cognitive function among the elderly women

Background

The association between handgrip strength combined with body mass index (BMI) and cognitive impairment has not been thoroughly examined. We aimed to investigate whether the relationship between handgrip strength and risk of cognitive impairment is altered by the presence of obesity in older women.

Methods

A total of 544 older women aged over 65 years without cognitive impairment from the Korean Longitudinal Study of Aging (KLoSA) were included in the study. Handgrip strength was classified in a binary manner (weak or strong) or in tertiles and obesity was defined as a BMI ≥ 25 kg/m², in accordance with the Asia-Pacific World Health Organization criteria. Incident cognitive impairment was defined as a Korean Mini-mental State Examination (K-MMSE) score of less than 24 after eight years of follow-up.

Results

Strong handgrip strength was associated with reduced likelihood of developing cognitive impairment compared to weak handgrip strength in obese women (adjusted odds ratio, aOR 0.23, 95% confidence interval, CI 0.08–0.66). The highest tertile of handgrip strength was associated with reduced risk of incident cognitive impairment (aOR 0.16, 95% CI 0.04–0.70), compared to the lowest tertile of handgrip strength in obese women, with a significant linear trend (p for trend = 0.016). Furthermore, the highest tertile of handgrip strength was significantly associated with smaller decline in K-MMSE scores compared to the lowest tertile of handgrip strength in obese women (p value = 0.009). There was no association between handgrip strength and incident cognitive impairment in non-obese women.

Conclusions

Strong handgrip strength was associated with reduced risk of cognitive impairment among obese women, but not in non-obese women. Handgrip strength may be a simple and useful marker for predicting future cognitive impairment among obese women.

Electronic supplementary material

The online version of this article (10.1186/s12877-018-0918-9) contains supplementary material, which is available to authorized users.

Lactobacilli and bifidobacteria ameliorate memory and learning deficits and oxidative stress in β-amyloid (1–42) injected rats

The gastrointestinal microbiota affects brain function, including memory and learning. In this study we investigated the effects of probiotics on memory and oxidative stress biomarkers in an experimental model of Alzheimer’s disease. Sixty rats were randomly divided into 5 groups: control; control-probiotics, which received probiotics for 8 weeks; sham operation, which received an intrahippocampal injection of phosphate-buffered saline; Alzheimer, which received an intrahippocampal injection of β-amyloid (Aβ1–42); and Alzheimer-probiotics, which in addition to being injected with Aβ1–42, received 2 g (1 × 1010 CFU/g) of probiotics (Lactobacillus acidophilus, L. fermentum, Bifidobacterium lactis, and B. longum) for 8 weeks. Memory and learning were measured using the Morris water maze, and oxidative stress biomarkers in the hippocampus were measured using ELISA kits. Morris water maze results indicated that compared with the Alzheimer group, the Alzheimer-probiotics group had significantly improved spatial memory, including shorter escape latency and travelled distance and greater time spent in the target quadrant. There was also improvement in oxidative stress biomarkers such as increased malondialdehyde levels and superoxide dismutase activity following the β-amyloid injection. Overall, it seems that probiotics play a role in improving memory deficit and inhibiting the pathological mechanisms of Alzheimer’s disease by modifying microbiota.

Comparative Evaluation of the Antioxidant and Anti-Alzheimer's Disease Potential of Coumestrol and Puerarol Isolated from Pueraria lobata Using Molecular Modeling Studies

The current study assesses the antioxidant effects of two similar isoflavonoids isolated from Pueraria lobata, coumestrol and puerarol, along with the cholinergic and amyloid-cascade pathways to mitigate Alzheimer’s disease (AD). Antioxidant activity was evaluated via 1,1-diphenyl-2-picryhydrazyl (DPPH) and peroxynitrite (ONOO⁻) scavenging ability further screened via ONOO⁻-mediated nitrotyrosine. Similarly, acetyl- and butyrylcholinesterase (AChE/BChE) and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) inhibitory activities were assessed together with docking and kinetic studies. Considering DPPH and ONOO⁻ scavenging activity, coumestrol (EC₅₀ values of 53.98 and 1.17 µM) was found to be more potent than puerarol (EC₅₀ values of 82.55 and 6.99 µM) followed by dose dependent inhibition of ONOO⁻-mediated nitrotyrosine. Coumestrol showed pronounced AChE and BChE activity with IC₅₀ values of 42.33 and 24.64 µM, respectively, acting as a dual cholinesterase (ChE) inhibitor. Despite having weak ChE inhibitory activity, puerarol showed potent BACE1 inhibition (28.17 µM). Kinetic studies of coumestrol showed AChE and BChE inhibition in a competitive and mixed fashion, whereas puerarol showed mixed inhibition for BACE1. In addition, docking simulations demonstrated high affinity and tight binding capacity towards the active site of the enzymes. In summary, we undertook a comparative study of two similar isoflavonoids differing only by a single aliphatic side chain and demonstrated that antioxidant agents coumestrol and puerarol are promising, potentially complementary therapeutics for AD.