The effect of age and obesity on platelet amyloid precursor protein processing and plasma markers of oxidative stress and inflammation

Poor Cognitive Agility Conservation in Obese Aging People

Life expectancy has been boosted in recent decades at expenses of increasing the age-associated diseases. Dementia, for its incidence, stands out among the pathologies associated with aging. The exacerbated cognitive deterioration disables people from carrying out their daily lives autonomously and this incidence increases exponentially after 65 years of age. The etiology of dementia is a miscellaneous combination of risk factors that restrain the quality of life of our elderly. In this sense, it has been established that some metabolic pathologies such as obesity and diabetes act as a risk factor for dementia development. In contrast, a high educational level, as well as moderate physical activity, have been shown to be protective factors against cognitive impairment and the development of dementia. In the present study, we have evaluated the metabolic composition of a population between 60-90 years old, mentally healthy and with high academic degrees. After assessing agility in mental state, we have established relationships between their cognitive abilities and their body composition. Our data support that excess body fat is associated with poorer maintenance of cognition, while higher percentages of muscle mass are associated with the best results in the cognitive tests.

A Review of miRNAs as Biomarkers and Effect of Dietary Modulation in Obesity Associated Cognitive Decline and Neurodegenerative Disorders

There has been a progressive increase in the prevalence of obesity and its comorbidities such as type 2 diabetes and cardiovascular diseases worldwide. Recent studies have suggested that the crosstalk between adipose tissue and central nervous system (CNS), through cellular mediators and signaling pathways, may causally link obesity with cognitive decline and give rise to neurodegenerative disorders. Several mechanisms have been proposed in obesity, including inflammation, oxidative stress, insulin resistance, altered lipid and cholesterol homeostasis, which may result in neuroinflammation, altered brain insulin signaling, amyloid-beta (Aβ) deposition and neuronal cell death. Since obesity is associated with functional and morphological alterations in the adipose tissues, the resulting peripheral immune response augments the development and progression of cognitive decline and increases susceptibility of neurodegenerative disorders, such as Alzheimer's Disease (AD) and Parkinson's Disease (PD). Studies have also elucidated an important role of high fat diet in the exacerbation of these clinical conditions. However, the underlying factors that propel and sustain this obesity associated cognitive decline and neurodegeneration, remains highly elusive. Moreover, the mechanisms linking these phenomena are not well-understood. The cumulative line of evidence have demonstrated an important role of microRNAs (miRNAs), a class of small non-coding RNAs that regulate gene expression and transcriptional changes, as biomarkers of pathophysiological conditions. Despite the lack of utility in current clinical practices, miRNAs have been shown to be highly specific and sensitive to the clinical condition being studied. Based on these observations, this review aims to assess the role of several miRNAs and aim to elucidate underlying mechanisms that link obesity with cognitive decline and neurodegenerative disorders. Furthermore, this review will also provide evidence for the effect of dietary modulation which can potentially ameliorate cognitive decline and neurodegenerative diseases associated with obesity.

Aβ misfolding in blood plasma is inversely associated with body mass index even in middle adulthood

Background

To understand the potential for early intervention and prevention measures in Alzheimer’s disease, the association between risk factors and early pathological change needs to be assessed. Hence, the aim of this study was to determine whether risk factors of Alzheimer’s clinical syndrome (clinical AD), such as body mass index (BMI), are associated with Aβ misfolding in blood, a strong risk marker for AD among older adults.

Methods

Information on risk factors and blood samples were collected at baseline in the ESTHER study, a population-based cohort study of older adults (age 50–75 years) in Germany. Aβ misfolding in blood plasma was analyzed using an immuno-infrared-sensor in a total of 872 participants in a nested case-control design among incident dementia cases and matched controls. Associations between risk factors and Aβ misfolding were assessed by multiple logistic regression. For comparison, the association between the risk factors and AD incidence during 17 years of follow-up was investigated in parallel among 5987 cohort participants.

Results

An inverse association with Aβ misfolding was seen for BMI at age 50 based on reported weight history (aOR 0.64, 95% CI 0.43–0.96, p = 0.03). Similar but not statistically significant associations were seen for BMI at baseline (i.e., mean age 68) and at age 40. No statistically significant associations with Aβ misfolding were found for other risk factors, such as diabetes, smoking, and physical activity. On the other hand, low physical activity was associated with a significantly reduced risk of developing clinical AD compared to physical inactivity.

Conclusions

Our results support that AD pathology may be detectable and associated with reduced weight even in middle adulthood, many years before clinical diagnosis of AD. Physical activity might reduce the risk of onset of AD symptoms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13195-021-00889-2.

Dexibuprofen ameliorates peripheral and central risk factors associated with Alzheimer's disease in metabolically stressed APPswe/PS1dE9 mice

BACKGROUND

Several studies stablished a relationship between metabolic disturbances and Alzheimer´s disease (AD) where inflammation plays a pivotal role. However, mechanisms involved still remain unclear. In the present study, we aimed to evaluate central and peripheral effects of dexibuprofen (DXI) in the progression of AD in APPswe/PS1dE9 (APP/PS1) female mice, a familial AD model, fed with high fat diet (HFD). Animals were fed either with conventional chow or with HFD, from their weaning until their sacrifice, at 6 months. Moreover, mice were divided into subgroups to which were administered drinking water or water supplemented with DXI (20 mg kg-1 d-1) for 3 months. Before sacrifice, body weight, intraperitoneal glucose and insulin tolerance test (IP-ITT) were performed to evaluate peripheral parameters and also behavioral tests to determine cognitive decline. Moreover, molecular studies such as Western blot and RT-PCR were carried out in liver to confirm metabolic effects and in hippocampus to analyze several pathways considered hallmarks in AD.

RESULTS

Our studies demonstrate that DXI improved metabolic alterations observed in transgenic animals fed with HFD in vivo, data in accordance with those obtained at molecular level. Moreover, an improvement of cognitive decline and neuroinflammation among other alterations associated with AD were observed such as beta-amyloid plaque accumulation and unfolded protein response.

CONCLUSIONS

Collectively, evidence suggest that chronic administration of DXI prevents the progression of AD through the regulation of inflammation which contribute to improve hallmarks of this pathology. Thus, this compound could constitute a novel therapeutic approach in the treatment of AD in a combined therapy.

Acceleration of α-synuclein fibril formation and associated cytotoxicity stimulated by silica nanoparticles as a model of neurodegenerative diseases

A wide range of biophysical and theoretical analysis were employed to explore the formation of (α-syn) amyloid fibril formation as a model of Parkinson's disease in the presence of silica oxide nanoparticles (SiO₂ NPs). Also, different cellular and molecular assays such as MTT, LDH, caspase, ROS, and qPCR were performed to reveal the α-syn amyloid fibrils-associated cytotoxicity against SH-SY5Y cells. Fluorescence measurements showed that SiO₂ NPs accelerate the α-syn aggregation and exposure of hydrophobic moieties. Congo red absorbance, circular dichroism (CD), and transmission electron microscopy (TEM) analysis depicted the SiO₂ NPs accelerated the formation of α-syn amyloid fibrils. Molecular docking study showed that SiO₂ clusters preferably bind to the N-terminal of α-syn as the helix folding site. We also realized that SiO₂ NPs increase the cytotoxicity of α-syn amyloid fibrils through a significant decrease in cell viability, increase in membrane leakage, activation of caspase-9 and -3, elevation of ROS, and increase in the ratio of Bax/Bcl2 mRNA. The cellular assay indicated that α-syn amyloid fibrils formed in the presence of SiO₂ NPs induce their cytotoxic effects through the mitochondrial-mediated intrinsic apoptosis pathway. We concluded that these data may reveal some adverse effects of NPs on the progression of Parkinson's disease.

Inflammatory Diseases and Vitamin E-What Do We Know and Where Do We Go?

Inflammation-driven diseases and related comorbidities, such as the metabolic syndrome, obesity, fatty liver disease, and cardiovascular diseases cause significant global burden. There is a growing body of evidence that nutrients alter inflammatory responses and can therefore make a decisive contribution to the treatment of these diseases. Recently, the inflammasome, a cytosolic multiprotein complex, has been identified as a key player in inflammation and the development of various inflammation-mediated disorders, with nucleotide-binding domain and leucine-rich repeat pyrin domain (NLRP) 3 being the inflammasome of interest. Here an overview about the cellular signaling pathways underlying nuclear factor "kappa-light-chain-enhancer" of activated B-cells (NF-κB)- and NLRP3-mediated inflammatory processes, and the pathogenesis of the inflammatory diseases atherosclerosis and non-alcoholic fatty liver disease (NAFLD) is provided; next, the current state of knowledge for drug-based and dietary-based interventions for treating cardiovascular diseases and NAFLD is discussed. To date, one of the most important antioxidants in the human diet is vitamin E. Various in vitro and in vivo studies suggest that the different forms of vitamin E and also their derivatives have anti-inflammatory activity. Recent publications suggest that vitamin E-and possibly metabolites of vitamin E-are a promising therapeutic approach for treating inflammatory diseases such as NAFLD.