The roles of lipid and glucose metabolism in modulation of β-amyloid, tau, and neurodegeneration in the pathogenesis of Alzheimer disease

Magnesium-L-threonate treats Alzheimer's disease by modulating the microbiota-gut-brain axis

JOURNAL/nrgr/04.03/01300535-202410000-00029/figure1/v/2024-02-06T055622Z/r/image-tiff Disturbances in the microbiota-gut-brain axis may contribute to the development of Alzheimer's disease. Magnesium-L-threonate has recently been found to have protective effects on learning and memory in aged and Alzheimer's disease model mice. However, the effects of magnesium-L-threonate on the gut microbiota in Alzheimer's disease remain unknown. Previously, we reported that magnesium-L-threonate treatment improved cognition and reduced oxidative stress and inflammation in a double-transgenic line of Alzheimer's disease model mice expressing the amyloid-β precursor protein and mutant human presenilin 1 (APP/PS1). Here, we performed 16S rRNA amplicon sequencing and liquid chromatography-mass spectrometry to analyze changes in the microbiome and serum metabolome following magnesium-L-threonate exposure in a similar mouse model. Magnesium-L-threonate modulated the abundance of three genera in the gut microbiota, decreasing Allobaculum and increasing Bifidobacterium and Turicibacter. We also found that differential metabolites in the magnesium-L-threonate-regulated serum were enriched in various pathways associated with neurodegenerative diseases. The western blotting detection on intestinal tight junction proteins (zona occludens 1, occludin, and claudin-5) showed that magnesium-L-threonate repaired the intestinal barrier dysfunction of APP/PS1 mice. These findings suggest that magnesium-L-threonate may reduce the clinical manifestations of Alzheimer's disease through the microbiota-gut-brain axis in model mice, providing an experimental basis for the clinical treatment of Alzheimer's disease.

Mass Spectrometry Imaging Reveals Region-Specific Lipid Alterations in the Mouse Brain in Response to Efavirenz Treatment

Efavirenz (EFV) is a commonly used drug to treat human immunodeficiency virus infection and is known to exert adverse effects on the brain. Although it is known that EFV is associated with abnormal plasma lipid levels, the changes in the spatial localization of individual lipid molecules in brain tissue following EFV treatment are yet to be explored. In this study, we employed a matrix-assisted laser desorption/ionization mass spectrometry imaging approach to determine region-specific lipid alterations in mouse brains following EFV treatment. We detected unique spatial localization patterns of phosphatidylcholine (PC), sphingomyelin (SM), ceramide phosphoinositol (PI-Cer), and hexosylceramide (HexCer) molecules in the mouse brain. Interestingly, PC(32:0), PC(38:5), and SM(36:1;O2) showed high abundance in the hippocampus region, whereas PI-Cer(38:8) exhibited low abundance in the hippocampus region of the EFV-treated mouse brains. Additionally, we observed low abundance of PC(38:6), PC(40:6), and PI-Cer(40:3) in the thalamus region of the EFV-treated mouse brains. Furthermore, SM(40:1;O2), SM(42:2;O2), SM(42:1;O2), SM(43:2;O2), and SM(43:1;O2) exhibited their accumulation in the corpus callosum region of the EFV-treated mouse brains as compared to controls. However, HexCer(42:1;O3) exhibited depletion in the corpus callosum region in response to EFV treatment. To characterize the expression patterns of proteins, including lipid metabolizing enzymes, in response to EFV treatment, mass spectrometry-based proteomics was utilized. From these, the expression levels of 12 brain proteins were found to be significantly decreased following EFV treatment. Taken together, these multiomics data provide important insights into the effects of EFV on brain lipid metabolism.

Deciphering ApoE Genotype-Driven Proteomic and Lipidomic Alterations in Alzheimer's Disease Across Distinct Brain Regions

Alzheimer's disease (AD) is a neurodegenerative disease with a complex etiology influenced by confounding factors such as genetic polymorphisms, age, sex, and race. Traditionally, AD research has not prioritized these influences, resulting in dramatically skewed cohorts such as three times the number of Apolipoprotein E (APOE) ε4-allele carriers in AD relative to healthy cohorts. Thus, the resulting molecular changes in AD have previously been complicated by the influence of apolipoprotein E disparities. To explore how apolipoprotein E polymorphism influences AD progression, 62 post-mortem patients consisting of 33 AD and 29 controls (Ctrl) were studied to balance the number of ε4-allele carriers and facilitate a molecular comparison of the apolipoprotein E genotype. Lipid and protein perturbations were assessed across AD diagnosed brains compared to Ctrl brains, ε4 allele carriers (APOE4+ for those carrying 1 or 2 ε4s and APOE4- for non-ε4 carriers), and differences in ε3ε3 and ε3ε4 Ctrl brains across two brain regions (frontal cortex (FCX) and cerebellum (CBM)). The region-specific influences of apolipoprotein E on AD mechanisms showcased mitochondrial dysfunction and cell proteostasis at the core of AD pathophysiology in the post-mortem brains, indicating these two processes may be influenced by genotypic differences and brain morphology.

Lacticaseibacillus rhamnosus HA-114 and Bacillus subtilis R0179 Prolong Lifespan and Mitigate Amyloid-β Toxicity in C. elegans via Distinct Mechanisms

Background

Recent advances linking gut dysbiosis with neurocognitive disorders such as Alzheimer's disease (AD) suggest that the microbiota-gut-brain axis could be targeted for AD prevention, management, or treatment.

Objective

We sought to identify probiotics that can delay Aβ-induced paralysis.

Methods

Using C. elegans expressing human amyloid-β (Aβ)1-42 in body wall muscles (GMC101), we assessed the effects of several probiotic strains on paralysis.

Results

We found that Lacticaseibacillus rhamnosus HA-114 and Bacillus subtilis R0179, but not their supernatants or heat-treated forms, delayed paralysis and prolonged lifespan without affecting the levels of amyloid-β aggregates. To uncover the mechanism involved, we explored the role of two known pathways involved in neurogenerative diseases, namely mitophagy, via deletion of the mitophagy factor PINK-1, and fatty acid desaturation, via deletion of the Δ9 desaturase FAT-5. Pink-1 deletion in GMC101 worms did not modify the life-prolonging and anti-paralysis effects of HA-114 but reduced the protective effect of R0179 against paralysis without affecting its life-prolonging effect. Upon fat5 deletion in GMC101 worms, the monounsaturated C14:1 and C16:1 FAs conserved their beneficial effect while the saturated C14:0 and C16:0 FAs did not. The beneficial effects of R0179 on both lifespan and paralysis remained unaffected by fat-5 deletion, while the beneficial effect of HA-114 on paralysis and lifespan was significantly reduced.

Conclusions

Collectively with clinical and preclinical evidence in other models, our results suggest that HA-114 or R0179 could be studied as potential therapeutical adjuncts in neurodegenerative diseases such as AD.

Parallel patterns of cognitive aging in marmosets and macaques

As humans age, some experience cognitive impairment while others do not. When impairment does occur, it is not expressed uniformly across cognitive domains and varies in severity across individuals. Translationally relevant model systems are critical for understanding the neurobiological drivers of this variability, which is essential to uncovering the mechanisms underlying the brain's susceptibility to the effects of aging. As such, non-human primates are particularly important due to shared behavioral, neuroanatomical, and age-related neuropathological features with humans. For many decades, macaque monkeys have served as the primary non-human primate model for studying the neurobiology of cognitive aging. More recently, the common marmoset has emerged as an advantageous model for this work due to its short lifespan that facilitates longitudinal studies. Despite their growing popularity as a model, whether marmosets exhibit patterns of age-related cognitive impairment comparable to those observed in macaques and humans remains unexplored. To address this major limitation for the development and evaluation of the marmoset as a model of cognitive aging, we directly compared working memory ability as a function of age in macaques and marmosets on the identical working memory task. Our results demonstrate that marmosets and macaques exhibit remarkably similar age-related working memory deficits, highlighting the value of the marmoset as a model for cognitive aging research within the neuroscience community.

Exploring the complexities of 1C metabolism: implications in aging and neurodegenerative diseases

The intricate interplay of one-carbon metabolism (OCM) with various cellular processes has garnered substantial attention due to its fundamental implications in several biological processes. OCM serves as a pivotal hub for methyl group donation in vital biochemical reactions, influencing DNA methylation, protein synthesis, and redox balance. In the context of aging, OCM dysregulation can contribute to epigenetic modifications and aberrant redox states, accentuating cellular senescence and age-associated pathologies. Furthermore, OCM's intricate involvement in cancer progression is evident through its capacity to provide essential one-carbon units crucial for nucleotide synthesis and DNA methylation, thereby fueling uncontrolled cell proliferation and tumor development. In neurodegenerative disorders like Alzheimer's and Parkinson's, perturbations in OCM pathways are implicated in the dysregulation of neurotransmitter synthesis and mitochondrial dysfunction, contributing to disease pathophysiology. This review underscores the profound impact of OCM in diverse disease contexts, reinforcing the need for a comprehensive understanding of its molecular complexities to pave the way for targeted therapeutic interventions across inflammation, aging and neurodegenerative disorders.

Exploring the effect of photobiomodulation and gamma visual stimulation induced by 808 nm and visible LED in Alzheimer's disease mouse model

Although photobiomodulation (PBM) and gamma visual stimulatqion (GVS) have been overwhelmingly explored in the recent time as a possible light stimulation (LS) means of Alzheimer's disease (AD) therapy, their effects have not been assessed at once. In our research, the AD mouse model was stimulated using light with various parameters [continuous wave (PBM) or 40 Hz pulsed visible LED (GVS) or 40 Hz pulsed 808 nm LED (PBM and GVS treatment)]]. The brain slices collected from the LS treated AD model mice were evaluated using (i) fluorescence microscopy to image thioflavine-S labeled amy-loid-β (Aβ) plaques (the main hallmark of AD), or (ii) two-photon excited fluorescence (TPEF) imaging of unlabeled Aβ plaques, showing that the amount of Aβ plaques was reduced after LS treatment. The imaging results correlated well with the results of Morris water maze (MWM) test, which demonstrated that the spatial learning and memory abilities of LS treated mice were noticeably higher than those of untreated mice. The LS effect was also assessed by in vivo nonlinear optical imaging, revealing that the cerebral amyloid angiopathy decreased spe-cifically as a result of 40 Hz pulsed 808 nm irradiation, on the contrary, the angiopathy reversed after visible 40 Hz pulsed light treatment. The obtained results provide useful reference for further optimization of the LS (PBM or GVS) parameters to achieve efficient phototherapy of AD.

Cognitive impairment in long-living adults: a genome-wide association study, polygenic risk score model and molecular modeling of the APOE protein

Background

Cognitive impairment is an irreversible, aging-associated condition that robs people of their independence. The purpose of this study was to investigate possible causes of this condition and propose preventive options.

Methods

We assessed cognitive status in long-living adults aged 90+ (n = 2,559) and performed a genome wide association study using two sets of variables: Mini-Mental State Examination scores as a continuous variable (linear regression) and cognitive status as a binary variable (> 24, no cognitive impairment; <10, impairment) (logistic regression).

Results

Both variations yielded the same polymorphisms, including a well-known marker of dementia, rs429358in the APOE gene. Molecular dynamics simulations showed that this polymorphism leads to changes in the structure of alpha helices and the mobility of the lipid-binding domain in the APOE protein.

Conclusion

These changes, along with higher LDL and total cholesterol levels, could be the mechanism underlying the development of cognitive impairment in older adults. However, this polymorphism is not the only determining factor in cognitive impairment. The polygenic risk score model included 45 polymorphisms (ROC AUC 69%), further confirming the multifactorial nature of this condition. Our findings, particularly the results of PRS modeling, could contribute to the development of early detection strategies for predisposition to cognitive impairment in older adults.

Alteration of Metabolic Profiles during the Progression of Alzheimer's Disease

(1) Background: Alzheimer's disease (AD) is a progressive neurodegenerative disorder that threatens the population health of older adults. However, the mechanisms of the altered metabolism involved in AD pathology are poorly understood. The aim of the study was to identify the potential biomarkers of AD and discover the metabolomic changes produced during the progression of the disease. (2) Methods: Gas chromatography-mass spectrometry (GC-MS) was used to measure the concentrations of the serum metabolites in a cohort of subjects with AD (n = 88) and a cognitively normal control (CN) group (n = 85). The patients were classified as very mild (n = 25), mild (n = 27), moderate (n = 25), and severe (n = 11). The serum metabolic profiles were analyzed using multivariate and univariate approaches. Least absolute shrinkage and selection operator (LASSO) logistic regression was applied to identify the potential biomarkers of AD. Biofunctional enrichment analysis was performed using the Kyoto Encyclopedia of Genes and Genomes. (3) Results: Our results revealed considerable separation between the AD and CN groups. Six metabolites were identified as potential biomarkers of AD (AUC > 0.85), and the diagnostic model of three metabolites could predict the risk of AD with high accuracy (AUC = 0.984). The metabolic enrichment analysis revealed that carbohydrate metabolism deficiency and the disturbance of amino acid, fatty acid, and lipid metabolism were involved in AD progression. Especially, the pathway analysis highlighted that l-glutamate participated in four crucial nervous system pathways (including the GABAergic synapse, the glutamatergic synapse, retrograde endocannabinoid signaling, and the synaptic vesicle cycle). (4) Conclusions: Carbohydrate metabolism deficiency and amino acid dysregulation, fatty acid, and lipid metabolism disorders were pivotal events in AD progression. Our study may provide novel insights into the role of metabolic disorders in AD pathogenesis and identify new markers for AD diagnosis.

Associations between dietary patterns and dementia-related neuroimaging markers

BACKGROUND

The exploration of associations between dietary patterns and dementia-related neuroimaging markers can provide insights on food combinations that may impact brain integrity.

METHODS

Data were derived from the Swedish Gothenburg H70 Birth Cohort Study (n = 610). Three dietary patterns were obtained using principal component analysis. Magnetic resonance imaging markers included cortical thickness, an Alzheimer's disease (AD) signature score, small vessel disease, and white matter microstructural integrity. Adjusted linear/ordinal regression analyses were performed.

RESULTS

A high-protein and alcohol dietary pattern was negatively associated with cortical thickness in the whole brain (Beta: -0.011; 95% confidence interval [CI]: -0.018 to -0.003), and with an Alzheimer's disease cortical thickness signature score (Beta: -0.013; 95% CI: -0.024 to -0.001). A positive association was found between a Mediterranean-like dietary pattern and white matter microstructural integrity (Beta: 0.078; 95% CI: 0.002-0.154). No associations were found with a Western-like dietary pattern.

DISCUSSION

Dietary patterns may impact brain integrity through neurodegenerative and vascular pathways.

HIGHLIGHTS

Certain dietary patterns were associated with dementia-related neuroimaging markers. A Mediterranean dietary pattern was positively associated with white matter microstructure. A high-protein and alcohol pattern was negatively associated with cortical thickness.

A rhein-huprine hybrid protects erythrocyte membrane integrity against Alzheimer's disease related Aβ(1-42) peptide

Alzheimer's disease remains largely unknown, and currently there is no complete cure for the disease. New synthetic approaches have been developed to create multi-target agents, such as RHE-HUP, a rhein-huprine hybrid which can modulate several biological targets that are relevant to the development of the disease. While RHE-HUP has shown in vitro and in vivo beneficial effects, the molecular mechanisms by which it exerts its protective effect on cell membranes have not been fully clarified. To better understand RHE-HUP interactions with cell membranes, we used synthetic membrane models and natural models of human membranes. For this purpose, human erythrocytes and molecular model of its membrane built-up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE) were used. The latter correspond to classes of phospholipids present in the outer and inner monolayers of the human erythrocyte membrane, respectively. X-ray diffraction and differential scanning calorimetry (DSC) results indicated that RHE-HUP was able to interact mainly with DMPC. In addition, scanning electron microscopy (SEM) analysis showed that RHE-HUP modified the normal biconcave shape of erythrocytes inducing the formation of echinocytes. Moreover, the protective effect of RHE-HUP against the disruptive effect of Aβ(1-42) on the studied membrane models was tested. X-ray diffraction experiments showed that RHE-HUP induced a recovery in the ordering of DMPC multilayers after the disruptive effect of Aβ(1-42), confirming the protective role of the hybrid.

Comparison of the relationship between cognitive function and future falls in Chinese community-dwelling older adults with and without diabetes mellitus

OBJECTIVE

The aim of this study was to determine whether cognitive function is associated with future falls in older patients with diabetes mellitus (DM) compared with those without DM. Cognitive function was divided into several domains to further analyze.

METHODS

A total of 678 individuals met the inclusion criteria and comprised the final study population. The mean age was 74.35 ± 5.35 years, and 58.9% of the participants were female (n = 400). At the baseline, cognitive function was measured by the Mini Mental State Examination (MMSE), and DM diagnoses were determined by medical records. The self-reported any falls data were obtained via face-to-face questioning at the 1-year follow-up.

RESULTS

At baseline, 15.6% of participants (n = 106) were diagnosed with DM. According to whether they had any falls during 1-year follow-up, there was a significant difference between the two group in fasting plasma glucose (p = 0.012) and DM (p = 0.036) at baseline. Among the older adults with DM, those who had experienced any falls had poorer cognitive function (p = 0.014). After adjusting for various covariates, we found that MMSE (95% CI 0.790-0.991, p = 0.034), orientation to place (95% CI 0.307-0.911, p = 0.022) and registration (95% CI 0.162-0.768, p = 0.009) were significantly associated with falls in the follow-up.

CONCLUSION

Our study found that in patients with DM, cognitive function is related to future falls. Not only overall cognitive function, but also orientation to place and registration were all associated with future falls in older adults with DM. When completing the fall risk assessment of elderly patients with DM, clinicians should give more attention to the testing of cognitive function.

Transcriptomic Changes Predict Metabolic Alterations in LC3 Associated Phagocytosis in Aged Mice

LC3b (Map1lc3b) plays an essential role in canonical autophagy and is one of several components of the autophagy machinery that mediates non-canonical autophagic functions. Phagosomes are often associated with lipidated LC3b to promote phagosome maturation in a process called LC3-associated phagocytosis (LAP). Specialized phagocytes, such as mammary epithelial cells, retinal pigment epithelial (RPE) cells, and sertoli cells, utilize LAP for optimal degradation of phagocytosed material, including debris. In the visual system, LAP is critical to maintain retinal function, lipid homeostasis, and neuroprotection. In a mouse model of retinal lipid steatosis-mice lacking LC3b (LC3b-/-), we observed increased lipid deposition, metabolic dysregulation, and enhanced inflammation. Herein, we present a non-biased approach to determine if loss of LAP mediated processes modulate the expression of various genes related to metabolic homeostasis, lipid handling, and inflammation. A comparison of the RPE transcriptome of WT and LC3b-/- mice revealed 1533 DEGs, with ~73% upregulated and 27% downregulated. Enriched gene ontology (GO) terms included inflammatory response (upregulated DEGs), fatty acid metabolism, and vascular transport (downregulated DEGs). Gene set enrichment analysis (GSEA) identified 34 pathways; 28 were upregulated (dominated by inflammation/related pathways) and 6 were downregulated (dominated by metabolic pathways). Analysis of additional gene families identified significant differences for genes in the solute carrier family, RPE signature genes, and genes with a potential role in age-related macular degeneration. These data indicate that loss of LC3b induces robust changes in the RPE transcriptome contributing to lipid dysregulation and metabolic imbalance, RPE atrophy, inflammation, and disease pathophysiology.

Transcriptomic changes predict metabolic alterations in LC3 associated phagocytosis in aged mice

LC3b ( Map1lc3b ) plays an essential role in canonical autophagy and is one of several components of the autophagy machinery that mediates non-canonical autophagic functions. Phagosomes are often associated with lipidated LC3b, to pro-mote phagosome maturation in a process called LC3-associated phagocytosis (LAP). Specialized phagocytes such as mammary epithelial cells, retinal pigment epithelial (RPE) cells, and sertoli cells utilize LAP for optimal degradation of phagocytosed material, including debris. In the visual system, LAP is critical to maintain retinal function, lipid homeostasis and neuroprotection. In a mouse model of retinal lipid steatosis - mice lacking LC3b ( LC3b ^-/- ), we observed increased lipid deposition, metabolic dysregulation and enhanced inflammation. Herein we present a non-biased approach to determine if loss of LAP mediated processes modulate the expression of various genes related to metabolic homeostasis, lipid handling, and inflammation. A comparison of the RPE transcriptome of WT and LC3b ^-/- mice revealed 1533 DEGs, with ~73% upregulated and 27% down-regulated. Enriched gene ontology (GO) terms included inflammatory response (upregulated DEGs), fatty acid metabolism and vascular transport (downregulated DEGs). Gene set enrichment analysis (GSEA) identified 34 pathways; 28 were upregulated (dominated by inflammation/related pathways) and 6 were downregulated (dominated by metabolic pathways). Analysis of additional gene families identified significant differences for genes in the solute carrier family, RPE signature genes, and genes with potential role in age-related macular degeneration. These data indicate that loss of LC3b induces robust changes in the RPE transcriptome contributing to lipid dysregulation and metabolic imbalance, RPE atrophy, inflammation, and disease pathophysiology.

3D genome-selected microRNAs to improve Alzheimer's disease prediction

Introduction

Alzheimer's disease (AD) is a type of neurodegenerative disease that has no effective treatment in its late stage, making the early prediction of AD critical. There have been an increase in the number of studies indicating that miRNAs play an important role in neurodegenerative diseases including Alzheimer's disease via epigenetic modifications including DNA methylation. Therefore, miRNAs may serve as excellent biomarkers in early AD prediction.

Methods

Considering that the non-coding RNAs' activity may be linked to their corresponding DNA loci in the 3D genome, we collected the existing AD-related miRNAs combined with 3D genomic data in this study. We investigated three machine learning models in this work under leave-one-out cross-validation (LOOCV): support vector classification (SVC), support vector regression (SVR), and knearest neighbors (KNNs).

Results

The prediction results of different models demonstrated the effectiveness of incorporating 3D genome information into the AD prediction models.

Discussion

With the assistance of the 3D genome, we were able to train more accurate models by selecting fewer but more discriminatory miRNAs, as witnessed by several ML models. These interesting findings indicate that the 3D genome has great potential to play an important role in future AD research.

Focus on Alzheimer's Disease: The Role of Fibroblast Growth Factor 21 and Autophagy

Alzheimer's disease (AD) is a disorder of the central nervous system that is typically marked by progressive cognitive impairment and memory loss. Amyloid β plaque deposition and neurofibrillary tangles with hyperphosphorylated tau are the two hallmark pathologies of AD. In mammalian cells, autophagy clears aberrant protein aggregates, thus maintaining proteostasis as well as neuronal health. Autophagy affects production and metabolism of amyloid β and accumulation of phosphorylated tau proteins, whose malfunction can lead to the progression of AD. On the other hand, defective autophagy has been found to induce the production of the neuroprotective factor fibroblast growth factor 21 (FGF21), although the underlying mechanism is unclear. In this review, we highlight the significance of aberrant autophagy in the pathogenesis of AD, discuss the possible mechanisms by which defective autophagy induces FGF21 production, and analyze the potential of FGF21 in the treatment of AD. The findings provide some insights into the potential role of FGF21 and autophagy in the pathogenesis of AD.

Amyloid-PET and White Matter Hyperintensities Have Independent Effects on Baseline Cognitive Function and Synergistic Effects on Longitudinal Executive Function

Co-occurrence of beta amyloid (Aβ) and white matter hyperintensities (WMHs) increase the risk of dementia and both are considered biomarkers of preclinical dementia. Moderation and mediation modeling were used to define the interplay between global and regional Aβ and WMHs measures in relation to executive function (EF) and memory composite scores outcomes at baseline and after approximately 2 years across a sample of 714 clinically normal participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI 2). The moderation regression analysis showed additive effects of Aβ and WMHs over baseline memory and EF scores (p = 0.401 and 0.061, respectively) and synergistic effects over follow-up EF (p < 0.05). Through mediation analysis, the data presented demonstrate that WMHs effects, mediated by global and regional amyloid burden, are responsible for baseline cognitive performance deficits in memory and EF. These findings suggest that Aβ and WMHs contribute to baseline cognition independently while WMHs volumes exert effects on baseline cognitive performance directly and through influences on Aβ accumulation.

Metformin use and brain atrophy in nondemented elderly individuals with diabetes

OBJECTIVE

There is a shred of growing evidence demonstrating that diabetic patients are at higher risk of developing Alzheimer's disease compared to the general population. The previous investigation showed the protective effect of metformin for delaying dementia in diabetic patients. However, there are limited data on the effect of metformin on structural changes. This study aims to investigate the effect of metformin on hippocampal and cortical volumes in non-demented diabetic individuals.

METHOD

We entered 157 non-demented diabetic subjects including 89 mild cognitive impairment (MCI), and 68 cognitively healthy individuals from Alzheimer's disease Neuroimaging Initiative (ADNI) which were then categorized as metformin users and non-users. We used the ANCOVA model for measuring the association between metformin use and hippocampal and cortical volumes.

RESULTS

Among 157 subjects with a mean age of 71.8 (±7.7) included in this study, 76 individuals were stratified as metformin users. Results of the univariate model indicate that metformin users had a higher right (p = 0.003) and left parietal lobe volume (p = 0.004). Moreover, the volume of left cingulate was higher in those who used metformin compared to those not used it (p = 0.027). Our results were also significant for the right frontal lobe and indicated that metformin users had higher volume (p = 0.035). There were no significant differences in the hippocampus, occipital, and temporal regions.

CONCLUSION

Our findings showed the protective effects of metformin on brain volumes in non-demented elderly individuals with diabetes. Comparing the groups show strong enough results regarding the lower atrophy in metformin users.

Yoga as a Preventive Intervention for Cardiovascular Diseases and Associated Comorbidities: Open-Label Single Arm Study

Aim

Common Yoga Protocol (CYP) is a standardized yoga protocol authored by experts from all over the world under the aegis of the Ministry of AYUSH, Ayurveda, Yoga and Naturopathy, Unani, Siddha, Sowa Rigpa and Homeopathy (AYUSH). The potential of CYP can be determined as a cost-effective lifestyle modification to prevent the risk of developing cardiovascular diseases (CVD).

Methods

In this prospective trial, we compared the effect of CYP at baseline and after 1 month. A total of 374 yoga-naïve participants performed CYP under the supervision of experienced trainers. Physiological [body mass index (BMI), blood pressure, percent oxygen saturation], biochemical (fasting blood glucose and lipid profile), and neurocognitive parameters were measured before and after the intervention.

Results

At day 30 of yoga practice, serum levels of low-density lipoprotein (LDL), total cholesterol (TC), and high-density lipoprotein (HDL) were found significantly improved as compared to the baseline levels observed at the time of enrollment. Similarly, the lipid profile was also obtained from experienced trainers and found to be significantly different from those of yoga-naïve volunteers. When the intervention was compared between the healthy yoga-naïve participants with yoga-naïve participants suffering from medical issues, it was found that cholesterol profile improved significantly in the healthy-naive group as compared to the diseased group (hypertension, diabetes, underwent surgery, and CVD).

Conclusion

These results highlight the need for further research to better understand the effects of yoga on the primary prevention of CVD.

Defects of Nutrient Signaling and Autophagy in Neurodegeneration

Neurons are post-mitotic cells that allocate huge amounts of energy to the synthesis of new organelles and molecules, neurotransmission and to the maintenance of redox homeostasis. In neurons, autophagy is not only crucial to ensure organelle renewal but it is also essential to balance nutritional needs through the mobilization of internal energy stores. A delicate crosstalk between the pathways that sense nutritional status of the cell and the autophagic processes to recycle organelles and macronutrients is fundamental to guarantee the proper functioning of the neuron in times of energy scarcity. This review provides a detailed overview of the pathways and processes involved in the balance of cellular energy mediated by autophagy, which when defective, precipitate the neurodegenerative cascade of Parkinson’s disease, frontotemporal dementia, amyotrophic lateral sclerosis or Alzheimer’s disease.

Exogenous lipase administration alters gut microbiota composition and ameliorates Alzheimer's disease-like pathology in APP/PS1 mice

Alzheimer's disease (AD) represents the most common form of dementia in the elderly with no available disease modifying treatments. Altered gut microbial composition has been widely acknowledged as a common feature of AD, which potentially contributes to progression or onset of AD. To assess the hypothesis that Candida rugosa lipase (CRL), which has been shown to enhance gut microbiome and metabolite composition, can rebalance the gut microbiome composition and reduce AD pathology, the treatment effects in APPswe/PS1de9 (APP/PS1) mice were investigated. The analysis revealed an increased abundance of Acetatifactor and Clostridiales vadin BB60 genera in the gut; increased lipid hydrolysis in the gut lumen, normalization of peripheral unsaturated fatty acids, and reduction of neuroinflammation and memory deficits post treatment. Finally, we demonstrated that the evoked benefits on memory could be transferred via fecal matter transplant (FMT) into antibiotic-induced microbiome-depleted (AIMD) wildtype mice, ameliorating their memory deficits. The findings herein contributed to improve our understanding of the role of the gut microbiome in AD's complex networks and suggested that targeted modification of the gut could contribute to amelioration of AD neuropathology.

Past, present and future of therapeutic strategies against amyloid-β peptides in Alzheimer's disease: a systematic review

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in ageing, affecting around 46 million people worldwide but few treatments are currently available. The etiology of AD is still puzzling, and new drugs development and clinical trials have high failure rates. Urgent outline of an integral (multi-target) and effective treatment of AD is needed. Accumulation of amyloid-β (Aβ) peptides is considered one of the fundamental neuropathological pillars of the disease, and its dyshomeostasis has shown a crucial role in AD onset. Therefore, many amyloid-targeted therapies have been investigated. Here, we will systematically review recent (from 2014) investigational, follow-up and review studies focused on anti-amyloid strategies to summarize and analyze their current clinical potential. Combination of anti-Aβ therapies with new developing early detection biomarkers and other therapeutic agents acting on early functional AD changes will be highlighted in this review. Near-term approval seems likely for several drugs acting against Aβ, with recent FDA approval of a monoclonal anti-Aβ oligomers antibody -aducanumab- raising hopes and controversies. We conclude that, development of oligomer-epitope specific Aβ treatment and implementation of multiple improved biomarkers and risk prediction methods allowing early detection, together with therapies acting on other factors such as hyperexcitability in early AD, could be the key to slowing this global pandemic.

The emerging role of the chondroitin sulfate proteoglycan family in neurodegenerative diseases

Chondroitin sulfate (CS) is a kind of linear polysaccharide that is covalently linked to proteins to form proteoglycans. Chondroitin sulfate proteoglycans (CSPGs) consist of a core protein, with one or more CS chains covalently attached. CSPGs are precisely regulated and they exert a variety of physiological functions by binding to adhesion molecules and growth factors. Widely distributed in the nervous system in human body, CSPGs contribute to the major component of extracellular matrix (ECM), where they play an important role in the development and maturation of the nervous system, as well as in the pathophysiological response to damage to the central nervous system (CNS). While there are more than 30 types of CSPGs, this review covers the roles of the most important ones, including versican, aggrecan, neurocan and NG2 in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis. The updated reports of the treatment of neurodegenerative diseases are involving CSPGs.

Abnormal amyloid beta metabolism in systemic abnormalities and Alzheimer's pathology: Insights and therapeutic approaches from periphery

Alzheimer's disease (AD) is an age-associated, multifactorial neurodegenerative disorder that is incurable. Despite recent success in treatments that partially improve symptomatic relief, they have failed in most clinical trials. Re-holding AD for accurate diagnosis and treatment is widely known as a challenging task. Lack of knowledge of basic molecular pathogenesis might be a possible reason for ineffective AD treatment. Historically, a majority of therapy-based studies have investigated the role of amyloid-β (Aβ peptide) in the central nervous system (CNS), whereas less is known about Aβ peptide in the periphery in AD. In this review, we provide a comprehensive summary of the current understanding of Aβ peptide metabolism (anabolism and catabolism) in the brain and periphery. We show that the abnormal metabolism of Aβ peptide is significantly linked with central-brain and peripheral abnormalities; the interaction between peripheral Aβ peptide metabolism and peripheral abnormalities affects central-brain Aβ peptide metabolism, suggesting the existence of significant communication between these two pathways of Aβ peptide metabolism. This close interaction between the central brain and periphery in abnormal Aβ peptide metabolism plays a key role in the development and progression of AD. In conclusion, we need to obtain a full understanding of the dynamic roles of Aβ peptide at the molecular level in both the brain and periphery in relation to the pathology of AD. This will not only provide new information regarding the complex disease pathology, but also offer potential new clues to improve therapeutic strategies and diagnostic biomarkers for the successful treatment of AD.

Interactions between dietary patterns and genetic factors in relation to incident dementia among 70-year-olds

PURPOSE

To investigate potential interactions between dietary patterns and genetic factors modulating risk for Alzheimer's disease (AD) in relation to incident dementia.

METHODS

Data were derived from the population-based Gothenburg H70 Birth Cohort Studies in Sweden, including 602 dementia-free 70-year-olds (examined 1992-93, or 2000-02; 64% women) followed for incident dementia until 2016. Two factors from a reduced rank regression analysis were translated into dietary patterns, one healthy (e.g., vegetables, fruit, and fish) and one western (e.g., red meat, refined cereals, and full-fat dairy products). Genetic risk was determined by APOE ε4 status and non-APOE AD-polygenic risk scores (AD-PRSs). Gene-diet interactions in relation to incident dementia were analysed with Cox regression models. The interaction p value threshold was < 0.1.

RESULTS

There were interactions between the dietary patterns and APOE ε4 status in relation to incident dementia (interaction p value threshold of < 0.1), while no evidence of interactions were found between the dietary patterns and the AD-PRSs. Those with higher adherence to a healthy dietary pattern had a reduced risk of dementia among ε4 non-carriers (HR: 0.77; 95% CI: 0.61; 0.98), but not among ε4 carriers (HR: 0.86; CI: 0.63; 1.18). Those with a higher adherence to the western dietary pattern had an increased risk of dementia among ε4 carriers (HR: 1.37; 95% CI: 1.05; 1.78), while no association was observed among ε4 non-carriers (HR: 0.99; CI: 0.81; 1.21).

CONCLUSIONS

The results of this study suggest that there is an interplay between dietary patterns and APOE ε4 status in relation to incident dementia.

Lipid Profiling of Alzheimer's Disease Brain Highlights Enrichment in Glycerol(phospho)lipid, and Sphingolipid Metabolism

Alzheimer's disease (AD) is reported to be closely linked with abnormal lipid metabolism. To gain a more comprehensive understanding of what causes AD and its subsequent development, we profiled the lipidome of postmortem (PM) human brains (neocortex) of people with a range of AD pathology (Braak 0-6). Using high-resolution mass spectrometry, we employed a semi-targeted, fully quantitative lipidomics profiling method (Lipidyzer) to compare the biochemical profiles of brain tissues from persons with mild AD (n = 15) and severe AD (AD; n = 16), and compared them with age-matched, cognitively normal controls (n = 16). Univariate analysis revealed that the concentrations of 420 lipid metabolites significantly (p < 0.05; q < 0.05) differed between AD and controls. A total of 49 lipid metabolites differed between mild AD and controls, and 439 differed between severe AD and mild AD. Interestingly, 13 different subclasses of lipids were significantly perturbed, including neutral lipids, glycerolipids, glycerophospholipids, and sphingolipids. Diacylglycerol (DAG) (14:0/14:0), triacylglycerol (TAG) (58:10/FA20:5), and TAG (48:4/FA18:3) were the most notably altered lipids when AD and control brains were compared (p < 0.05). When we compare mild AD and control brains, phosphatidylethanolamine (PE) (p-18:0/18:1), phosphatidylserine (PS) (18:1/18:2), and PS (14:0/22:6) differed the most (p < 0.05). PE (p-18:0/18:1), DAG (14:0/14:0), and PS (18:1/20:4) were identified as the most significantly perturbed lipids when AD and mild AD brains were compared (p < 0.05). Our analysis provides the most extensive lipid profiling yet undertaken in AD brain tissue and reveals the cumulative perturbation of several lipid pathways with progressive disease pathology. Lipidomics has considerable potential for studying AD etiology and identifying early diagnostic biomarkers.

A Tau-Driven Adverse Outcome Pathway Blueprint Toward Memory Loss in Sporadic (Late-Onset) Alzheimer's Disease with Plausible Molecular Initiating Event Plug-Ins for Environmental Neurotoxicants

The worldwide prevalence of sporadic (late-onset) Alzheimer's disease (sAD) is dramatically increasing. Aging and genetics are important risk factors, but systemic and environmental factors contribute to this risk in a still poorly understood way. Within the frame of BioMed21, the Adverse Outcome Pathway (AOP) concept for toxicology was recommended as a tool for enhancing human disease research and accelerating translation of data into human applications. Its potential to capture biological knowledge and to increase mechanistic understanding about human diseases has been substantiated since. In pursuit of the tau-cascade hypothesis, a tau-driven AOP blueprint toward the adverse outcome of memory loss is proposed. Sequences of key events and plausible key event relationships, triggered by the bidirectional relationship between brain cholesterol and glucose dysmetabolism, and contributing to memory loss are captured. To portray how environmental factors may contribute to sAD progression, information on chemicals and drugs, that experimentally or epidemiologically associate with the risk of AD and mechanistically link to sAD progression, are mapped on this AOP. The evidence suggests that chemicals may accelerate disease progression by plugging into sAD relevant processes. The proposed AOP is a simplified framework of key events and plausible key event relationships representing one specific aspect of sAD pathology, and an attempt to portray chemical interference. Other sAD-related AOPs (e.g., Aβ-driven AOP) and a better understanding of the impact of aging and genetic polymorphism are needed to further expand our mechanistic understanding of early AD pathology and the potential impact of environmental and systemic risk factors.

A multitude of signaling pathways associated with Alzheimer's disease and their roles in AD pathogenesis and therapy

The exact molecular mechanisms associated with Alzheimer's disease (AD) pathology continue to represent a mystery. In the past decades, comprehensive data were generated on the involvement of different signaling pathways in the AD pathogenesis. However, the utilization of signaling pathways as potential targets for the development of drugs against AD is rather limited due to the immense complexity of the brain and intricate molecular links between these pathways. Therefore, finding a correlation and cross-talk between these signaling pathways and establishing different therapeutic targets within and between those pathways are needed for better understanding of the biological events responsible for the AD-related neurodegeneration. For example, autophagy is a conservative cellular process that shows link with many other AD-related pathways and is crucial for maintenance of the correct cellular balance by degrading AD-associated pathogenic proteins. Considering the central role of autophagy in AD and its interplay with many other pathways, the finest therapeutic strategy to fight against AD is the use of autophagy as a target. As an essential step in this direction, this comprehensive review represents recent findings on the individual AD-related signaling pathways, describes key features of these pathways and their cross-talk with autophagy, represents current drug development, and introduces some of the multitarget beneficial approaches and strategies for the therapeutic intervention of AD.

Mindful walking and cognition in older adults: A proof of concept study using in-lab and ambulatory cognitive measures

Mindfulness practice and walking have been linked individually to sustain cognition in older adults. This early-phase study aimed to establish proof-of-concept by evaluating whether an intervention that integrates light-intensity walking with mindfulness practices shows promising signs of improving cognition in older adults. Participants (N = 25, Mage = 72.4 ± 6.45) were community-dwelling older adults who engaged in a supervised mindful walking program over one month (8 sessions total, 2 sessions per week, 30-minute slow walking containing mindfulness skills). They completed performance-based and subjective ratings of cognitive measures in field before and after two mindful walking bouts using a smartphone app. They also completed in-lab performance-based and self-report cognitive measures at baseline and after the entire program. Controlling for demographics, potential covariates, and time trends, short-term improvements in perceived cognition and processing speed were observed from pre- to post-mindful walking sessions (i.e., 30 min) across multiple ambulatory cognitive measures (Cohen's ds range = 0.46-0.66). Longer-term improvements in processing speed and executive function were observed between baseline and end of the program (i.e., one month) across various performance-based cognitive measures (ds range = 0.43-1.28). No significant changes were observed for other cognitive domains. This early-phase study (Phase IIa) provides preliminary support that mindful walking activity is promising for sustaining cognition in older adults. Our promising findings form the building blocks of evidence needed to advance this intervention to a fully powered randomized controlled trial that examines program efficacy with a comparator. Favorable outcomes will inform the development of this lifestyle behavioral strategy for promoting healthy brain aging in late adulthood.

Concussion/Mild Traumatic Brain Injury (TBI) Induces Brain Insulin Resistance: A Positron Emission Tomography (PET) Scanning Study

Brain injury/concussion is a growing epidemic throughout the world. Although evidence supports association between traumatic brain injury (TBI) and disturbance in brain glucose metabolism, the underlying molecular mechanisms are not well established. Previously, we reported the release of cellular prion protein (PrPc) from the brain to circulation following TBI. The PrPc level was also found to be decreased in insulin-resistant rat brains. In the present study, we investigated the molecular link between PrPc and brain insulin resistance in a single and repeated mild TBI-induced mouse model. Mild TBI was induced in mice by dropping a weight (~95 g at 1 m high) on the right side of the head. The procedure was performed once and thrice (once daily) for single (SI) and repeated induction (RI), respectively. Micro PET/CT imaging revealed that RI mice showed significant reduction in cortical, hippocampal and cerebellum glucose uptake compared to SI and control. Mice that received RI also showed significant motor and cognitive deficits. In co-immunoprecipitation, the interaction between PrPc, flotillin and Cbl-associated protein (CAP) observed in the control mice brains was disrupted by RI. Lipid raft isolation showed decreased levels of PrPc, flotillin and CAP in the RI mice brains. Based on observation, it is clear that PrPc has an interaction with CAP and the dislodgment of PrPc from cell membranes may lead to brain insulin resistance in a mild TBI mouse model. The present study generated a new insight into the pathogenesis of brain injury, which may result in the development of novel therapy.

The Neuroprotective Effect of L-Carnitine against Glyceraldehyde-Induced Metabolic Impairment: Possible Implications in Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive cognitive regression and memory loss. Dysfunctions of both glucose metabolism and mitochondrial dynamics have been recognized as the main upstream events of the degenerative processes leading to AD. It has been recently found that correcting cell metabolism by providing alternative substrates can prevent neuronal injury by retaining mitochondrial function and reducing AD marker levels. Here, we induced an AD-like phenotype by using the glycolysis inhibitor glyceraldehyde (GA) and explored whether L-carnitine (4-N-trimethylamino-3-hydroxybutyric acid, LC) could mitigate neuronal damage, both in SH-SY5Y neuroblastoma cells and in rat primary cortical neurons. We have already reported that GA significantly modified AD marker levels; here we demonstrated that GA dramatically compromised cellular bioenergetic status, as revealed by glycolysis and oxygen consumption rate (OCR) evaluation. We found that LC ameliorated cell survival, improved OCR and ATP synthesis, prevented the loss of the mitochondrial membrane potential (Δψ_m) and reduced the formation of reactive oxygen species (ROS). Of note, the beneficial effect of LC did not rely on the glycolytic pathway rescue. Finally, we noticed that LC significantly reduced the increase in pTau levels induced by GA. Overall, these findings suggest that the use of LC can promote cell survival in the setting of the metabolic impairments commonly observed in AD. Our data suggest that LC may act by maintaining mitochondrial function and by reducing the pTau level.

Heterogeneous effects of genetic risk for Alzheimer's disease on the phenome

Here we report how four major forms of Alzheimer's disease (AD) genetic risk-APOE-ε4, APOE-ε2, polygenic risk and familial risk-are associated with 273 traits in ~500,000 individuals in the UK Biobank. The traits cover blood biochemistry and cell traits, metabolic and general health, psychosocial health, and cognitive function. The difference in the profile of traits associated with the different forms of AD risk is striking and may contribute to heterogenous presentation of the disease. However, we also identify traits significantly associated with multiple forms of AD genetic risk, as well as traits showing significant changes across ages in those at high risk of AD, which may point to their potential roles in AD etiology. Finally, we highlight how survivor effects, in particular those relating to shared risks of cardiovascular disease and AD, can generate associations that may mislead interpretation in epidemiological AD studies. The UK Biobank provides a unique opportunity to powerfully compare the effects of different forms of AD genetic risk on the phenome in the same cohort.

Functional effects of berberine in modulating mitochondrial dysfunction and inflammatory response in the respective amyloidogenic cells and activated microglial cells - In vitro models simulating Alzheimer's disease pathology

AIM

Berberine (BBR) is an alkaloid extracted from Coptidis Rhizoma, also known as Huang-Lian. Huang-Lian has been used extensively in traditional Chinese medicine for the treatment of various diseases, including diabetes and dementia. Because Alzheimer's disease (AD) is a complex disease that involves various pathophysiological changes, the diverse neuroprotective effects of BBR may be useful for improving the brain's energy state at an early stage of the disease.

MAIN METHODS

We performed extracellular flux and ¹H NMR-based metabolic profiling analyses to investigate the effects of BBR on metabolic processes in these cells. Pioglitazone (PIO), a peroxisome proliferator-activated receptor-γ (PPARγ) agonist has been studied extensively for the treatment of AD. We explored the combination dosing effects of BBR and PIO in vitro, then leveraged computational methods to explain the experimental finding.

KEY FINDINGS

BBR demonstrates potential in modulating the mitochondrial bioenergetics and attenuating dysfunction of the primary energy and glutathione metabolism pathways in an AD cell model. It also suppresses basal respiration and reduces the production of pro-inflammatory cytokines in activated microglial cells. Both experimental and computational observations indicate that BBR and PIO have comparable binding affinities to the PPARγ protein, suggesting both drugs may have some overlapping effects for AD.

SIGNIFICANCE

BBR exerts beneficial effects on disrupted metabolic processes in amyloidogenic cells and activated microglial cells, which are important for preventing or delaying early-stage disease progression. The choice of BBR or PIO for AD treatment depends on their respective pharmacokinetic profiles, delivery, efficacy and safety, and warrants further study.

Antidiabetic Drugs in Alzheimer's Disease and Mild Cognitive Impairment: A Systematic Review

INTRODUCTION

Considering that Alzheimer's disease (AD) and diabetes mellitus share pathophysiological features and AD remains with no cure, antidiabetic drugs like intranasal insulin, glitazones, metformin, and liraglutide are being tested as a potential treatment.

OBJECTIVE

The aim of this systematic review was to assess the efficacy of antidiabetic drugs in patients with AD, mild cognitive impairment (MCI), or subjective cognitive complaints (SCCs). Cognition was studied as the primary outcome and modulation of AD biomarkers, and imaging was also assessed as a secondary outcome.

METHODS

We conducted a search in the electronic databases PubMed/MEDLINE, EMBASE, and Scopus seeking clinical trials evaluating the effect on cognition of antidiabetic drugs in patients with AD, MCI, or SCCs.

RESULTS

A total of 23 articles were found eligible. Intranasal regular insulin improved verbal memory in most studies, especially in apoE4- patients, but results in other cognitive domains were unclear. Detemir improved cognition after 2 months of treatment, but it did not after 4 months. Pioglitazone improved cognition in diabetic patients with AD or MCI in 3 clinical trials, but it is controversial as 2 other studies did not show effect. Metformin and liraglutide showed promising results, but further research is needed as just 2 clinical trials involved each of these drugs. Almost all drugs tested were shown to modulate AD biomarkers and imaging.

CONCLUSIONS

Intranasal insulin, pioglitazone, metformin, and liraglutide are promising drugs that could be useful in the treatment of AD. However, many questions remain to be answered in future studies, so no particular antidiabetic drug can currently be recommended to treat AD.

A Western-style dietary pattern is associated with cerebrospinal fluid biomarker levels for preclinical Alzheimer's disease-A population-based cross-sectional study among 70-year-olds

BACKGROUND

Diet may be a modifiable factor for reducing the risk of Alzheimer's disease (AD). Western-style dietary patterns are considered to increase the risk, whereas Mediterranean-style dietary patterns are considered to reduce the risk. An association between diet and AD-related biomarkers have been suggested, but studies are limited.

AIM

To investigate potential relations between dietary patterns and cerebrospinal fluid (CSF) biomarkers for AD among dementia-free older adults.

METHODS

Data were derived from the population-based Gothenburg H70 Birth Cohort Studies, Sweden. A total of 269 dementia-free 70-year-olds with dietary and cerebrospinal fluid (CSF) amyloid beta (Aβ42 and Aβ40), total tau (t-tau), and phosphorylated tau (p-tau) data were investigated. Dietary intake was determined by the diet history method, and four dietary patterns were derived by principal component analysis. A Western dietary pattern, a Mediterranean/prudent dietary pattern, a high-protein and alcohol pattern, and a high-total and saturated fat pattern. Logistic regression models, with CSF biomarker pathology (yes/no) as dependent variables, and linear regression models with continuous CSF biomarker levels as dependent variables were performed. The analyses were adjusted for sex, energy intake, body mass index (BMI), educational level, and physical activity level.

RESULTS

The odds ratio for having total tau pathology (odds ratio [OR] 1.43; 95% confidence interval [CI] 1.02 to 2.01) and preclinical AD (Aβ42 and tau pathology; OR 1.79; 95% CI 1.03 to 3.10) was higher among those with a higher adherence to a Western dietary pattern. There were no other associations between the dietary patterns and CSF biomarkers that remained significant in both unadjusted and adjusted models.

DISCUSSION

Our findings suggest that higher adherence to a Western dietary pattern may be associated with pathological levels of AD biomarkers in the preclinical phase of AD. These findings can be added to the increasing amount of evidence linking diet with AD and may be useful for future intervention studies investigating dietary intake in relation to AD.

Advances in Understanding of the Role of Lipid Metabolism in Aging

During aging, body adiposity increases with changes in the metabolism of lipids and their metabolite levels. Considering lipid metabolism, excess adiposity with increased lipotoxicity leads to various age-related diseases, including cardiovascular disease, cancer, arthritis, type 2 diabetes, and Alzheimer's disease. However, the multifaceted nature and complexities of lipid metabolism make it difficult to delineate its exact mechanism and role during aging. With advances in genetic engineering techniques, recent studies have demonstrated that changes in lipid metabolism are associated with aging and age-related diseases. Lipid accumulation and impaired fatty acid utilization in organs are associated with pathophysiological phenotypes of aging. Changes in adipokine levels contribute to aging by modulating changes in systemic metabolism and inflammation. Advances in lipidomic techniques have identified changes in lipid profiles that are associated with aging. Although it remains unclear how lipid metabolism is regulated during aging, or how lipid metabolites impact aging, evidence suggests a dynamic role for lipid metabolism and its metabolites as active participants of signaling pathways and regulators of gene expression. This review describes recent advances in our understanding of lipid metabolism in aging, including established findings and recent approaches.

Perilipin 4 Protein: an Impending Target for Amyotrophic Lateral Sclerosis

The pathogenesis of amyotrophic lateral sclerosis (ALS) might exist some relationships with the abnormal lipidomic metabolisms. Therefore, we observed and analyzed the alteration of perilipin 4 (PLIN 4) distribution in the anterior horns (AH); the central canals (CC) and its surrounding gray matter; the posterior horns (PH); and the anterior, lateral, and posterior funiculus (AF, LF, and PF) of the cervical, thoracic, and lumbar segments, as well as the alteration of PLIN 4 expression in the entire spinal cords at the pre-onset, onset, and progression stages of Tg(SOD1*G93A)1Gur (TG) mice and the same period of wild-type(WT) by fluorescent immunohistochemistry, the Western blot, and the image analysis. Results showed that the PLIN 4 distributions in the spinal AH, CC and its surrounding gray matter, PH, AF, and PF of the cervical, thoracic, and lumbar segments in the TG mice at the pre-onset, onset, and progression stages significantly increased compared with those at the same periods of WT mice; the gray matter was especially significant. No significant changes were detected in the LF. PLIN 4 extensively distributed in the neurons and the proliferation neural cells. The PLIN 4 distributions significantly gradually increased from the pre-onset to onset to progression stages, and significantly correlated with the gradual increase death of neural cells. Total PLIN 4 expression in the spinal cords of TG mice significantly increased from the pre-onset, to onset, and to progression stages compared with that in the WT mice. Our data suggested that the PLIN 4 distribution and expression alterations might participate in the death of neural cells in the pathogenesis of ALS through modulating the lipidomic metabolisms and the neural cell proliferation.

Alzheimer's disease treatment: The share of herbal medicines

One of the most frequent forms of dementia in neurological disorders is Alzheimer's disease (AD). It is a chronic neurodegenerative disease characterized by impaired learning and memory. Pathological symptoms as extracellular amyloid-beta (Aβ) plaques and intracellular accumulation of neurofibrillary tangles occur in AD. Due to the aging of the population and increased prevalence of AD, discovery of new therapeutic agents with the highest effectiveness and fewer side effect seems to be necessary. Numerous synthetic medicines such as tacrine, donepezil, galantamine, rivastigmine, memantine, glutathione, ascorbic acid, ubiquinone, ibuprofen, and ladostigil are routinely used for reduction of the symptoms and prevention of disease progression. Nowadays, herbal medicines have attracted popular attention for numerous beneficial effects with little side effects. Lavandula angustifolia, Ginkgo biloba, Melissa officinalis, Crocus sativus, Ginseng, Salvia miltiorrhiza, and Magnolia officinalis have been widely used for relief of symptoms of some neurological disorders. This paper reviews the therapeutic effects of phytomedicines with prominent effects against various factors implicated in the emergence and progression of AD.

Plasma metabolomics of presymptomatic PSEN1-H163Y mutation carriers: a pilot study

BACKGROUND AND OBJECTIVE

PSEN1-H163Y carriers, at the presymptomatic stage, have reduced ¹⁸ FDG-PET binding in the cerebrum of the brain (Scholl et al., Neurobiol Aging 32:1388-1399, 2011). This could imply dysfunctional energy metabolism in the brain. In this study, plasma of presymptomatic PSEN1 mutation carriers was analyzed to understand associated metabolic changes.

METHODS

We analyzed plasma from noncarriers (NC, n = 8) and presymptomatic PSEN1-H163Y mutation carriers (MC, n = 6) via untargeted metabolomics using gas and liquid chromatography coupled with mass spectrometry, which identified 1199 metabolites. All the metabolites were compared between MC and NC using univariate analysis, as well as correlated with the ratio of Aβ_{1-42/A β 1-40} , using Spearman's correlation. Altered metabolites were subjected to Ingenuity Pathway Analysis (IPA).

RESULTS

Based on principal component analysis the plasma metabolite profiles were divided into dataset A and dataset B. In dataset A, when comparing between presymptomatic MC and NC, the levels of 79 different metabolites were altered. Out of 79, only 14 were annotated metabolites. In dataset B, 37 metabolites were significantly altered between presymptomatic MC and NC and nine metabolites were annotated. In both datasets, annotated metabolites represent amino acids, fatty acyls, bile acids, hexoses, purine nucleosides, carboxylic acids, and glycerophosphatidylcholine species. 1-docosapentaenoyl-GPC was positively correlated, uric acid and glucose were negatively correlated with the ratio of plasma Aβ_1-42 /Aβ_1-40 (P < 0.05).

INTERPRETATION

This study finds dysregulated metabolite classes, which are changed before the disease symptom onset. Also, it provides an opportunity to compare with sporadic Alzheimer's Disease. Observed findings in this study need to be validated in a larger and independent Familial Alzheimer's Disease (FAD) cohort.

A Rationale for Hypoxic and Chemical Conditioning in Huntington's Disease

Neurodegenerative diseases are characterized by adverse cellular environments and pathological alterations causing neurodegeneration in distinct brain regions. This development is triggered or facilitated by conditions such as hypoxia, ischemia or inflammation and is associated with disruptions of fundamental cellular functions, including metabolic and ion homeostasis. Targeting intracellular downstream consequences to specifically reverse these pathological changes proved difficult to translate to clinical settings. Here, we discuss the potential of more holistic approaches with the purpose to re-establish a healthy cellular environment and to promote cellular resilience. We review the involvement of important molecular pathways (e.g., the sphingosine, δ-opioid receptor or N-Methyl-D-aspartate (NMDA) receptor pathways) in neuroprotective hypoxic conditioning effects and how these pathways can be targeted for chemical conditioning. Despite the present scarcity of knowledge on the efficacy of such approaches in neurodegeneration, the specific characteristics of Huntington’s disease may make it particularly amenable for such conditioning techniques. Not only do classical features of neurodegenerative diseases like mitochondrial dysfunction, oxidative stress and inflammation support this assumption, but also specific Huntington’s disease characteristics: a relatively young age of neurodegeneration, molecular overlap of related pathologies with hypoxic adaptations and sensitivity to brain hypoxia. The aim of this review is to discuss several molecular pathways in relation to hypoxic adaptations that have potential as drug targets in neurodegenerative diseases. We will extract the relevance for Huntington’s disease from this knowledge base.

DMPK mRNA Expression in Human Brain Tissue Throughout the Lifespan

Objective

Myotonic dystrophy is a multisystem disorder caused by a trinucleotide repeat expansion on the myotonic dystrophy protein kinase (DMPK) gene. To determine whether wildtype DMPK expression patterns vary as a function of age, we analyzed DMPK expression in the brain from 99 donors ranging from 5 postconceptional weeks to 80 years old.

Methods

We used the BrainSpan messenger RNA sequencing and the Yale Microarray data sets, which included brain tissue samples from 42 and 57 donors, respectively. Collectively, donors ranged in age from 5 postconceptional weeks to 80 years old. DMPK expression was normalized for each donor across regions available in both data sets. Restricted cubic spline linear regression models were used to analyze the effects of log-transformed age and sex on normalized DMPK expression data.

Results

Age was a statistically significant predictor of normalized DMPK expression pattern in the human brain in the BrainSpan (p < 0.005) and Yale data sets (p < 0.005). Sex was not a significant predictor. Across both data sets, normalized wildtype DMPK expression steadily increases during fetal development, peaks around birth, and then declines to reach a nadir around age 10.

Conclusions

Peak expression of DMPK coincides with a time of dynamic brain development. Abnormal brain DMPK expression due to myotonic dystrophy may have implications for early brain development.

Inclusion of African American/Black adults in a pilot brain proteomics study of Alzheimer's disease

Alzheimer's disease (AD) disproportionately affects certain racial and ethnic subgroups, such as African American/Black and Hispanic adults. Genetic, comorbid, and socioeconomic risk factors contribute to this disparity; however, the molecular contributions have been largely unexplored. Herein, we conducted a pilot proteomics study of postmortem brains from African American/Black and non-Hispanic White adults neuropathologically diagnosed with AD compared to closely-matched cognitively normal individuals. Examination of hippocampus, inferior parietal lobule, and globus pallidus regions using quantitative proteomics resulted in 568 differentially-expressed proteins in AD. These proteins were consistent with the literature and included glial fibrillary acidic protein, peroxiredoxin-1, and annexin A5. In addition, 351 novel proteins in AD were identified, which could partially be due to cohort diversity. From linear regression analyses, we identified 185 proteins with significant race x diagnosis interactions across various brain regions. These differences generally were reflective of differential expression of proteins in AD that occurred in only a single racial/ethnic group. Overall, this pilot study suggests that disease understanding can be furthered by including diversity in racial/ethnic groups; however, this must be done on a larger scale.

A systematic review and meta-analysis: The effects of probiotic supplementation on metabolic profile in patients with neurological disorders

BACKGROUND AND OBJECTIVE

The objective of meta-analysis of randomized controlled trials (RCTs) was to evaluate the effects of probiotic supplementation on metabolic status in patients with neurological disorders.

METHODS

The following databases were search up to April 2019: Pubmed, Scopus, Google scholar, Web of Science, and Cochrane Central Register of Controlled Trials. The quality of the relevant extracted data was assessed according to the Cochrane risk of bias tool. Data were pooled by the use of the inverse variance method and expressed as mean difference with 95 % Confidence Intervals (95 % CI).

RESULTS

Nine studies were included in this meta-analysis. The findings suggested that probiotic supplementation resulted in a significant reduction in C-reactive protein (CRP) [Weighted Mean Difference (WMD): -1.06; 95 % CI: -1.80, -0.32] and malondialdehyde (MDA) levels (WMD: -0.32; 95 % CI: -0.46, -0.18). Supplementation with probiotics also significantly reduced insulin (WMD: -3.02; 95 % CI: -3.88, -2.15) and homeostatic model assessment for insulin resistance (HOMA-IR) (WMD: -0.71; 95 % CI: -0.89, -0.52). Probiotics significantly reduced triglycerides (WMD: -18.38; 95 % CI: -25.50, -11.26) and VLDL-cholesterol (WMD: -3.16; 95 % CI: -4.53, -1.79), while they increased HDL-cholesterol levels (WMD: 1.52; 95 % CI: 0.29, 2.75).

CONCLUSION

This meta-analysis demonstrated that taking probiotic by patients with neurological disorders had beneficial effects on CRP, MDA, insulin, HOMA-IR, triglycerides, VLDL-cholesterol and HDL-cholesterol levels, but did not affect other metabolic parameters.

The Interplay between Diabetes and Alzheimer's Disease-In the Hunt for Biomarkers

The brain is an organ in which energy metabolism occurs most intensively and glucose is an essential and dominant energy substrate. There have been many studies in recent years suggesting a close relationship between type 2 diabetes mellitus (T2DM) and Alzheimer’s disease (AD) as they have many pathophysiological features in common. The condition of hyperglycemia exposes brain cells to the detrimental effects of glucose, increasing protein glycation and is the cause of different non-psychiatric complications. Numerous observational studies show that not only hyperglycemia but also blood glucose levels near lower fasting limits (72 to 99 mg/dL) increase the incidence of AD, regardless of whether T2DM will develop in the future. As the comorbidity of these diseases and earlier development of AD in T2DM sufferers exist, new AD biomarkers are being sought for etiopathogenetic changes associated with early neurodegenerative processes as a result of carbohydrate disorders. The S100B protein seem to be interesting in this respect as it may be a potential candidate, especially important in early diagnostics of these diseases, given that it plays a role in both carbohydrate metabolism disorders and neurodegenerative processes. It is therefore necessary to clarify the relationship between the concentration of the S100B protein and glucose and insulin levels. This paper draws attention to a valuable research objective that may in the future contribute to a better diagnosis of early neurodegenerative changes, in particular in subjects with T2DM and may be a good basis for planning experiments related to this issue as well as a more detailed explanation of the relationship between the neuropathological disturbances and changes of glucose and insulin concentrations in the brain.

Decreased excitability of locus coeruleus neurons during hypercapnia is exaggerated in the streptozotocin-model of Alzheimer's disease

The locus coeruleus (LC) is a pontine nucleus important for respiratory control and central chemoreception. It is affected in Alzheimer's disease (AD) and alteration of LC cell function may account for respiratory problems observed in AD patients. In the current study, we tested the electrophysiological properties and CO₂/pH sensitivity of LC neurons in a model for AD. Sporadic AD was induced in rats by intracerebroventricular injection of 2 mg/kg streptozotocin (STZ), which induces behavioral and molecular impairments found in AD. LC neurons were recorded using the patch clamp technique and tested for responses to CO₂ (10% CO₂, pH = 7.0). The majority (~60%) of noradrenergic LC neurons in adult rats were inhibited by CO₂ exposure as indicated by a significant decrease in action potential (AP) discharge to step depolarizations. The STZ-AD rat model had a greater sensitivity to CO₂ than controls. The increased CO₂-sensitivity was demonstrated by a significantly stronger inhibition of activity during hypercapnia that was in part due to hyperpolarization of the resting membrane potential. Reduction of AP discharge in both groups was generally accompanied by lower LC network activity, depolarized AP threshold, increased AP repolarization, and increased current through a subpopulation of voltage-gated K⁺ channels (K_V). The latter was indicated by enhanced transient K_V currents particularly in the STZ-AD group. Interestingly, steady-state K_V currents were reduced under hypercapnia, a change that would favor enhanced AP discharge. However, the collective response of most LC neurons in adult rats, and particularly those in the STZ-AD group, was inhibited by CO₂.

The Differential Effect of Treadmill Exercise Intensity on Hippocampal Soluble Aβ and Lipid Metabolism in APP/PS1 Mice

Alzheimer's disease (AD) is characterized clinically by progressive impairments in learning and memory. Accumulating evidence suggests that regular exercise plays a neuroprotective role in aging-associated memory loss. Our previous study has confirmed that long-term treadmill exercise initiated either before or during the onset of β-amyloid (Aβ) pathology, was beneficial for reducing the levels of soluble Aβ and further improved cognition. In this study, in APP/PS1 mice, we assessed changes in soluble Aβ, and various blood biochemistry and molecular biological indices to assess whether exercise modulated lipid metabolism and thereby decelerated AD progression. Our results show that long-term treadmill exercise reduced the total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels, and increased the level of high-density lipoprotein cholesterol. Exercise also decreased the levels of soluble Aβ1-40 and Aβ1-42, down-regulated retinoid X receptor expression, and up-regulated liver X receptor, Apolipoprotein E, Low density lipoprotein receptor, Low density lipoprotein receptor-related protein 1, and ATP-binding cassette transporter A1 expression. This indicates that long-term treadmill exercise alters the lipoprotein content, increases lipid metabolism and cholesterol transportation, reduces the soluble Aβ, and therein plays an important neuroprotective role and delays AD progression. We further show that medium exercise intensity (60%-70% of maximal oxygen uptake) was more efficacious in increasing lipid metabolism and reducing blood lipid levels and soluble Aβ levels, than low-intensity exercise (45-55% of maximal oxygen uptake). This research has broad prospects and implications, and offers a theoretical basis for the prevention of AD.

Quantitative Trait Module-Based Genetic Analysis of Alzheimer's Disease

The pathological features of Alzheimer's Disease (AD) first appear in the medial temporal lobe and then in other brain structures with the development of the disease. In this work, we investigated the association between genetic loci and subcortical structure volumes of AD on 393 samples in the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort. Brain subcortical structures were clustered into modules using Pearson's correlation coefficient of volumes across all samples. Module volumes were used as quantitative traits to identify not only the main effect loci but also the interactive effect loci for each module. Thirty-five subcortical structures were clustered into five modules, each corresponding to a particular brain structure/area, including the limbic system (module I), the corpus callosum (module II), thalamus-cerebellum-brainstem-pallidum (module III), the basal ganglia neostriatum (module IV), and the ventricular system (module V). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results indicate that the gene annotations of the five modules were distinct, with few overlaps between different modules. We identified several main effect loci and interactive effect loci for each module. All these loci are related to the function of module structures and basic biological processes such as material transport and signal transduction.