scholarly journals Inflammation and Insulin Resistance as Risk Factors and Potential Therapeutic Targets for Alzheimer’s Disease

2021 ◽  
Vol 15 ◽  
Author(s):  
Angeles Vinuesa ◽  
Carlos Pomilio ◽  
Amal Gregosa ◽  
Melisa Bentivegna ◽  
Jessica Presa ◽  
...  

Overnutrition and modern diets containing high proportions of saturated fat are among the major factors contributing to a low-grade state of inflammation, hyperglycemia and dyslipidemia. In the last decades, the global rise of type 2 diabetes and obesity prevalence has elicited a great interest in understanding how changes in metabolic function lead to an increased risk for premature brain aging and the development of neurodegenerative disorders such as Alzheimer’s disease (AD). Cognitive impairment and decreased neurogenic capacity could be a consequence of metabolic disturbances. In these scenarios, the interplay between inflammation and insulin resistance could represent a potential therapeutic target to prevent or ameliorate neurodegeneration and cognitive impairment. The present review aims to provide an update on the impact of metabolic stress pathways on AD with a focus on inflammation and insulin resistance as risk factors and therapeutic targets.

2021 ◽  
pp. 107385842110407
Author(s):  
Wenhui Qu ◽  
Ling Li

As resident immune cells of the brain, microglia serve pivotal roles in regulating neuronal function under both physiological and pathological conditions, including aging and the most prevalent neurodegenerative disease, Alzheimer’s disease (AD). Instructed by neurons, microglia regulate synaptic function and guard brain homeostasis throughout life. Dysregulation of microglial function, however, can lead to dire consequences, including aggravated cognitive decline during aging and exacerbated neuropathology in diseases. The triggering receptor expressed on myeloid cells 2 (TREM2) is a key regulator of microglial function. Loss-of-function variants of TREM2 are associated with an increased risk of AD. TREM2 orchestrates the switch of microglial transcriptome programming that modulates microglial chemotaxis, phagocytosis, and inflammatory responses, as well as microglial regulation of synaptic function in health and disease. Intriguingly, the outcome of microglial/TREM2 function is influenced by age and the context of neuropathology. This review summarizes the rapidly growing research on TREM2 under physiological conditions and in AD, particularly highlighting the impact of TREM2 on neuronal function.


2005 ◽  
Vol 33 (5) ◽  
pp. 1041-1044 ◽  
Author(s):  
G.J. Biessels ◽  
L.J. Kappelle

Type II diabetes mellitus (DM2) is associated with an increased risk of cognitive dysfunction and dementia. The increased risk of dementia concerns both Alzheimer's disease and vascular dementia. Although some uncertainty remains into the exact pathogenesis, several mechanisms through which DM2 may affect the brain have now been identified. First, factors related to the ‘metabolic syndrome’, a cluster of metabolic and vascular risk factors (e.g. dyslipidaemia and hypertension) that is closely linked to DM2, may be involved. A number of these risk factors are predictors of cerebrovascular disease, accelerated cognitive decline and dementia. Secondly, hyperglycaemia may be involved, through adverse effects of potentially ‘toxic’ glucose metabolites on the brain and its vasculature. Thirdly, insulin itself may be involved. Insulin can directly modulate synaptic plasticity and learning and memory, and disturbances in insulin signalling pathways in the periphery and in the brain have recently been implicated in Alzheimer's disease and brain aging. Insulin also regulates the metabolism of β-amyloid and tau, the building blocks of amyloid plaques and neurofibrillary tangles, the neuropathological hallmarks of Alzheimer's disease. In this paper, the evidence for the association between DM2 and dementia and for each of these underlying mechanisms will be reviewed, with emphasis on the role of insulin itself.


2014 ◽  
Vol 39 (1-2) ◽  
pp. 105-115 ◽  
Author(s):  
Jong Bin Bae ◽  
You Joung Kim ◽  
Ji Won Han ◽  
Tae Hui Kim ◽  
Joon Hyuk Park ◽  
...  

Background/Aims: Knowledge of incidence rates and risk factors is essential for the development of strategies to treat patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Methods: A subpopulation of the Nationwide Survey on Dementia Epidemiology (460 Korean subjects aged ≥65 years from 2 rural and 2 urban districts) was followed up for 3.5 years. The age-specific incidence was estimated and risk factors were identified. Results: The age-standardized incidence of AD and MCI was 7.9 and 28.1 cases per 1,000 person-years, respectively. MCI was associated with a 6-fold increased risk of AD. Depression was a risk factor for AD with MCI. Age, lack of formal education, illiteracy, rural residence, and marital status were associated with the risk of AD. Conclusion: Strategies to control modifiable risk factors should be implemented to decrease the incidence of AD. © 2014 S. Karger AG, Basel


2008 ◽  
Vol 10 (3) ◽  
pp. 345-357 ◽  

There is a strong association between late-life depression, cognitive impairment, cerebrovascular disease, and poor cognitive outcomes, including progressive dementia, especially Alzheimer's disease. While neuroimaging evidence suggests that cerebrovascular disease plays a prominent role, it seems that depression alone may also confer substantial risk for developing Alzheimer's disease. The relationships between the prominent cerebrovascular changes, other structural abnormalities, specific forms of cognitive dysfunction, and increased risk for developing Alzheimer's disease among those with late-life depression have been difficult to reconcile. The varied findings suggest that there are likely multiple pathways to poor cognitive outcomes. We present a framework outlining multiple, non-mutually exclusive etiologic links between depression, cognitive impairment, and progressive decline, including dementia. Importantly, the model is both testable and falsifiable. Going forward, using models such as this to inform research should accelerate knowledge acquisition on the depression/dementia relationship that may be useful for dementia prevention, monitoring the impact of depression treatment on clinical status and course of illness.


2019 ◽  
Vol 34 (6) ◽  
pp. 846-846
Author(s):  
J Osuna ◽  
K Thomas ◽  
E Edmonds ◽  
K Bangen ◽  
A Weigand ◽  
...  

Abstract Objective Early identification of those at risk for mild cognitive impairment (MCI) and Alzheimer’s disease (AD) is critical for early intervention. Recent work shows that subtle cognitive decline (SCD), operationally-defined using sensitive neuropsychological scores, predicts progression to MCI/AD and is associated with AD biomarkers. We aimed to determine whether SCD adds unique value in predicting progression to MCI/AD above and beyond other AD risk factors. Method 547 cognitively unimpaired participants from the Alzheimer’s Disease Neuroimaging Initiative (359 without SCD; 188 with SCD) underwent neuropsychological testing and lumbar puncture. Participants were classified as SCD if they performed >1 SD below the demographically-adjusted mean on 1) two neuropsychological total scores in different cognitive domains, or 2) two memory test process scores (e.g., intrusion errors), or 3) one total score and one process score. Cox regressions examined whether SCD status predicted progression to MCI and AD within 5 years after adjusting for age, education, sex, MMSE, depressive symptoms, ischemia risk, apolipoprotein E genotype, and AD biomarker “positivity” based on the cerebrospinal fluid phosphorylated tau-to-β-amyloid ratio. Results SCD status predicted progression to MCI (HR = 2.74, 95% CI = 2.07-3.63, p < .001) and AD (HR = 2.20, 95% CI = 1.04-4.65, p = .04) within 5 years, even after including known AD risk factors in the model. Conclusion SCD conveys a 2-3 fold increased risk of progression to MCI/AD and is a unique predictor above and beyond risk factors that are commonly used in preclinical AD research. These findings support our novel SCD criteria as a cost-effective and non-invasive method for identifying those at risk for future cognitive decline.


Author(s):  
A. Rosenberg ◽  
F. Mangialasche ◽  
T. Ngandu ◽  
A. Solomon ◽  
M. Kivipelto

Alzheimer’s disease (AD) and dementia are a global public health priority, and prevention has been highlighted as a pivotal component in managing the dementia epidemic. Modifiable risk factors of dementia and AD include lifestyle-related factors, vascular and metabolic disorders, and psychosocial factors. Randomized controlled clinical trials (RCTs) are needed to clarify whether modifying such factors can prevent or postpone cognitive impairment and dementia in older adults. Given the complex, multifactorial, and heterogeneous nature of late-onset AD and dementia, interventions targeting several risk factors and mechanisms simultaneously may be required for optimal preventive effects. The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) is the first large, long-term RCT to demonstrate that a multidomain lifestyle-based intervention ameliorating vascular and lifestyle-related risk factors can preserve cognitive functioning and reduce the risk of cognitive decline among older adults at increased risk of dementia. To investigate the multidomain intervention in other populations and diverse cultural and geographical settings, the World-Wide FINGERS (WW-FINGERS) network was recently launched (https://alz.org/wwfingers). Within this network, new FINGER-type trials with shared core methodology, but local culture and context-specific adaptations, will be conducted in several countries. The WW-FINGERS initiative facilitates international collaborations, provides a platform for testing multidomain strategies to prevent cognitive impairment and dementia, and aims at generating high-quality scientific evidence to support public health and clinical decision-making. Furthermore, the WW-FINGERS network can support the implementation of preventive strategies and translation of research findings into practice.


2020 ◽  
Vol 17 ◽  
Author(s):  
Hyung-Ji Kim ◽  
Jae-Hong Lee ◽  
E-nae Cheong ◽  
Sung-Eun Chung ◽  
Sungyang Jo ◽  
...  

Background: Amyloid PET allows for the assessment of amyloid β status in the brain, distinguishing true Alzheimer’s disease from Alzheimer’s disease-mimicking conditions. Around 15–20% of patients with clinically probable Alzheimer’s disease have been found to have no significant Alzheimer’s pathology on amyloid PET. However, a limited number of studies had been conducted this subpopulation in terms of clinical progression. Objective: We investigated the risk factors that could affect the progression to dementia in patients with amyloid-negative amnestic mild cognitive impairment (MCI). Methods: This study was a single-institutional, retrospective cohort study of patients over the age of 50 with amyloidnegative amnestic MCI who visited the memory clinic of Asan Medical Center with a follow-up period of more than 36 months. All participants underwent brain magnetic resonance imaging (MRI), detailed neuropsychological testing, and fluorine-18[F18]-florbetaben amyloid PET. Results: During the follow-up period, 39 of 107 patients progressed to dementia from amnestic MCI. In comparison with the stationary group, the progressed group had a more severe impairment in verbal and visual episodic memory function and hippocampal atrophy, which showed an Alzheimer’s disease-like pattern despite the lack of evidence for significant Alzheimer’s disease pathology. Voxel-based morphometric MRI analysis revealed that the progressed group had a reduced gray matter volume in the bilateral cerebellar cortices, right temporal cortex, and bilateral insular cortices. Conclusion: Considering the lack of evidence of amyloid pathology, clinical progression of these subpopulation may be caused by other neuropathologies such as TDP-43, abnormal tau or alpha synuclein that lead to neurodegeneration independent of amyloid-driven pathway. Further prospective studies incorporating biomarkers of Alzheimer’s diseasemimicking dementia are warranted.


2021 ◽  
pp. 1-6
Author(s):  
Dianxu Ren ◽  
Oscar L. Lopez ◽  
Jennifer H. Lingler ◽  
Yvette Conley

We examined the association between APOE ɛ2/ɛ4 with incident Alzheimer’s disease (AD) and mild cognitive impairment (MCI) among African Americans using the national dataset from the National Alzheimer’s Coordinating Center (NACC) from 2005 to September 2019. Compared to ɛ3/ɛ3 carriers, ɛ2/ɛ4 carriers exhibited a similar risk of incident AD (adjusted hazard ratio [aHR] = 0.85, 95% CI [0.39, 1.84]) among the AD cohort and similar risk of incident MCI (aHR = 0.88, 95% CI [0.51, 1.50]) among the MCI cohort. Our findings suggest that, unlike the increased risk of AD and MCI in non-Latino whites, APOE ɛ2/ɛ4 genotype is not associated with the incidence of AD and MCI among African Americans.


2021 ◽  
Vol 8 (1) ◽  
pp. e000759
Author(s):  
Daniel Higbee ◽  
Raquel Granell ◽  
Esther Walton ◽  
Roxanna Korologou-Linden ◽  
George Davey Smith ◽  
...  

RationaleLarge retrospective case-control studies have reported an association between chronic obstructive pulmonary disease (COPD), reduced lung function and an increased risk of Alzheimer’s disease. However, it remains unclear if these diseases are causally linked, or due to shared risk factors. Conventional observational epidemiology suffers from unmeasured confounding and reverse causation. Additional analyses addressing causality are required.ObjectivesTo examine a causal relationship between COPD, lung function and Alzheimer’s disease.MethodsUsing two-sample Mendelian randomisation, we used single nucleotide polymorphisms (SNPs) identified in a genome wide association study (GWAS) for lung function as instrumental variables (exposure). Additionally, we used SNPs discovered in a GWAS for COPD in those with moderate to very severe obstruction. The effect of these SNPs on Alzheimer’s disease (outcome) was taken from a GWAS based on a sample of 24 807 patients and 55 058 controls.ResultsWe found minimal evidence for an effect of either lung function (OR: 1.02 per SD; 95% CI 0.91 to 1.13; p value 0.68) or liability for COPD on Alzheimer’s disease (OR: 0.97 per SD; 95% CI 0.92 to 1.03; p value 0.40).ConclusionNeither reduced lung function nor liability COPD are likely to be causally associated with an increased risk of Alzheimer’s, any observed association is likely due to unmeasured confounding. Scientific attention and health prevention policy may be better focused on overlapping risk factors, rather than attempts to reduce risk of Alzheimer’s disease by targeting impaired lung function or COPD directly.


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