Impact of statins on mortality and disease progression in patients with Alzheimer's disease: a nationwide cohort study.

Rac1b Increases with Progressive Tau Pathology within Cholinergic Nucleus Basalis Neurons in Alzheimer's Disease

Circadian fragmentation: a harbinger of Alzheimer's disease?

Battle against Alzheimer's Disease: The Scope and Potential Value of Magnetic Resonance Imaging Biomarkers

The hippocampus is a vulnerable and plastic brain structure that is damaged by a variety of stimuli, e.g. hypoxia, hypoperfusion, hypoglycaemia, stress and seizures. Alzheimer's disease is a common and important disorder in which hippocampal atrophy is reported. Indeed, the available evidence suggests that hippocampal atrophy is the starting point of the pathogenesis of Alzheimer's disease and a significant number of patients with hippocampal atrophy will develop Alzheimer's disease. Studies indicate that hippocampal atrophy has functional consequences, e.g. cognitive impairment. Deposition of tau protein, formation of neurofibrillary tangles and accumulation of β-amyloid (Aβ) contributes to hippocampal atrophy together with damage caused by several other factors. Some of the factors associated with the development of hippocampal atrophy in Alzheimer's disease have been identified, e.g. hypertension, diabetes mellitus, hyperlipidaemia, seizures, affective disturbances and stress, and more is being learnt about other factors. Hypertension can potentially damage the hippocampus through ischaemia caused by atherosclerosis and cerebral amyloid angiopathy. Diabetes can produce hippocampal lesions via both vascular and non-vascular pathologies and can reduce the threshold for hippocampal damage. Carriers of the apolipoprotein E (ApoE)-ε4 genotype have been shown to have greater mesial temporal atrophy and poorer memory functions than non-carriers. In addition to giving rise to abnormal lipid metabolism, the ApoE-ε4 allele can affect the course of Alzheimer's disease via both Aβ-dependent and -independent pathways. Repetitive seizures can increase Aβ-peptide production and cause neurotransmission dysfunction and cytoskeletal abnormalities or a combination of these. Affective disturbances and stress are proposed to increase corticosteroid-induced hippocampal damage in many different ways. In the absence of any specific markers for predicting Alzheimer's disease progression, it seems appropriate to learn more about the various predictors of hippocampal atrophy that determine the progression of Alzheimer's disease from mild cognitive impairment (MCI), and then attempt to address these. It would be interesting to know to what extent these predictors play a role in the development of MCI or hasten the conversion of MCI to full-blown Alzheimer's disease. Finally, it would be useful to know the extent to which these predictors can worsen or aggravate existing Alzheimer's disease. Of the clinically used drugs in Alzheimer's disease, anticholinesterases have been shown to slow down the rate of progression of hippocampal atrophy. One study observed that the neuroprotective effect of these agents is possibly due to an anti-Aβ effect produced by cholinergic stimulation. Similarly, antihypertensive and antihyperglycaemic drugs (pioglitazone and insulin) have been shown to reduce the risk of Alzheimer's disease or disease progression. Currently, there are no disease-modifying therapies available for Alzheimer's disease. It has been suggested that for treatment to be most effective, the regimen must be started before significant downstream damage has occurred (i.e. before the clinical diagnosis of Alzheimer's disease, at the stage of MCI or earlier). Since the hippocampus is a plastic structure and atrophy of this structure is closely related to the pathophysiology of Alzheimer's disease, if we could control blood pressure, regulate blood sugar, treat behavioural and psychological symptoms, achieve satisfactory lipid lowering and maintain a seizure-free state in patients with Alzheimer's disease, this may not only improve disease control but could also potentially affect the rate of disease progression.

Model-Based Economic Evaluation in Alzheimer's Disease: A Review of the Methods Available to Model Alzheimer's Disease Progression

Alzheimer's disease (AD) is the leading cause of dementia; however, men and women face differential AD prevalence, presentation, and progression risks. Characterizing metabolomic profiles during AD progression is fundamental to understand the metabolic disruptions and the biological pathways involved. However, outstanding questions remain of whether peripheral metabolic changes occur equally in men and women with AD. Here, we evaluated differential effects of metabolomic and brain volume associations between sexes. We used three cohorts from the Alzheimer's Disease Neuroimaging Initiative (ADNI), evaluated 1,368 participants, two metabolomic platforms with 380 metabolites in total, and six brain segment volumes. Using dimension reduction techniques, we took advantage of the correlation structure of the brain volume phenotypes and the metabolite concentration values to reduce the number of tests while aggregating relevant biological structures. Using WGCNA, we aggregated modules of highly co-expressed metabolites. On the other hand, we used partial least squares regression-discriminant analysis (PLS-DA) to extract components of brain volumes that maximally co-vary with AD diagnosis as phenotypes. We tested for differences in effect sizes between sexes in the association between single metabolite and metabolite modules with the brain volume components. We found five metabolite modules and 125 single metabolites with significant differences between sexes. These results highlight a differential lipid disruption in AD progression between sexes. Men showed a greater negative association of phosphatidylcholines and sphingomyelins and a positive association of VLDL and large LDL with AD progression. In contrast, women showed a positive association of triglycerides in VLDL and small and medium LDL with AD progression. Explicitly identifying sex differences in metabolomics during AD progression can highlight particular metabolic disruptions in each sex. Our research study and strategy can lead to better-tailored studies and better-suited treatments that take sex differences into account.

Spatial-temporal lipidomics reveals dysregulated lipid metabolism in mouse brain during Alzheimer's disease progression.

The FAS gene, brain volume, and disease progression in Alzheimer's disease

Multi-omics reveals changes in astrocyte fatty acid metabolism during early stages of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is characterized pathologically by the presence of senile plaques, neurofibrillary tangles, and synapse loss. Increasing evidence supports a role of amyloid beta-peptide (Abeta)-induced oxidative stress in the progression and pathogenesis of AD. In this review, we summarize evidence for a role of oxidative stress in the progression of AD by comparing the appearance of the same oxidized brain proteins from subjects with mild cognitive impairment (MCI), early AD (EAD), and late-stage AD, and relating these findings to the reported AD pathology. The identification of oxidized brain proteins in common in MCI, EAD, and AD brain suggest that certain key pathways are triggered and may be involved in the progression of AD. Exploring these pathways in detail may provide clues for better understanding the pathogenesis and progression of AD and also for the development of effective therapies to treat or delay this dementing disorder.

Background/Aims: Measuring and predicting Alzheimer's disease (AD) progression is important in order to adjust treatment and allocate care resources. We aimed to identify a combination of subtests from the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery (CERAD-NB) that best correlated with AD progression in follow-up as well as to predict AD progression. Method: A total of 236 participants with very mild [Clinical Dementia Rating (CDR) = 0.5] or mild AD (CDR = 1.0) at baseline were followed up for 3 years. The CERAD-NB and Mini-Mental State Examination (MMSE) were used to assess cognition, and the CDR scale sum of boxes (CDR-sb) was employed to evaluate AD progression. Generalized estimating equations were used to develop models to predict and follow up disease progression. Results: Performance declined on all CERAD-NB subtests. The ability of the separate subtests to distinguish between groups (baseline CDR = 0.5 or 1.0) diminished during follow-up. The best combination of subtests that explained 62% of CDR-sb variance in follow-up included verbal fluency, constructional praxis, the clock drawing test, and the MMSE. Baseline values of the same combination predicted 37% of the CDR-sb change. Conclusion: A short version of the CERAD-NB subtests provides a promising and time-efficient alternative for measuring cognitive deterioration during AD follow-up. Although the initial signs of AD include memory difficulties, it may be useful to assess non-memory tasks in follow-up.

Impact of diet and exercise on mitochondrial quality and mitophagy in Alzheimer's disease.

There is an urgent need to understand the relationships between amyloid-β (Aβ) and tau in the progression of Alzheimer's disease to identify treatment targets. Here we examine reciprocal predictions of brain Aβ burden quantified by positron emission tomography and CSF concentrations of Aβ42 and phosphorylated tau (p-tau). Each biomarker was examined over 48 months in two separate cross-lagged models; one in asymptomatic healthy elderly people (men and women), and one in patients with Alzheimer's disease (AD) dementia or mild cognitive impairment (MCI). The models examine predictions of each biomarker on the progression of the others, considering each previous and concurrent measure. In healthy elderly, lower CSF Aβ42 predicted Aβ deposition and reciprocally, Aβ burden predicted a decrease in CSF Aβ42. Lower CSF Aβ42 predicted an increase in CSF p-tau, and CSF p-tau predicted Aβ deposition. In AD/MCI, lower CSF Aβ42 predicted Aβ deposition and Aβ burden reciprocally predicted CSF Aβ42 changes; however, in contrast to healthy elderly, CSF p-tau concentrations did not predict Aβ biomarkers, or vice versa. In post hoc models examining cognitive status, CSF Aβ42 predicted Mini Mental State Examination (MMSE) scores in healthy elderly, whereas Aβ burden and CSF p-tau predicted MMSE scores in AD/MCI. The findings describe reciprocal predictions between Aβ and tau biomarkers in healthy elderly and they implicate mechanisms underlying low CSF Aβ42 in Alzheimer's disease pathogenesis and progression. In symptomatic Alzheimer's disease, CSF Aβ42 and Aβ deposition predicted each other; however, Aβ and CSF p-tau progressed independently and they independently predicted cognitive decline.SIGNIFICANCE STATEMENT This study offers empirical evidence concerning the hypothesized "amyloid cascade", as it progressed over 4 years in healthy elderly people and in Alzheimer's disease patients. In healthy elderly, CSF amyloid changes predicted amyloid deposition, CSF phosphorylated tau concentrations, and a decline in cognitive status. Phosphorylated tau concentrations specifically predicted amyloid deposition. In Alzheimer's disease patients, although amyloid deposition and CSF amyloid changes continued to "cascade", there was no evidence to suggest that amyloid and tau biomarkers predicted each other, although both amyloid deposition and CSF tau progression predicted cognitive decline independently. Taking advantage of repeated amyloid PET and CSF measures, this dynamic view offers new insight into the progression of Alzheimer's disease biomarkers and their relationships with cognitive decline.

The protective effect of statin on Alzheimer disease (AD) is still controversial, probably due to the debate about when to start the use of statin and the lack of any large-scale randomized evidence that actually supports the hypothesis. The purpose of this study was to examine the protective effect of early statin use on mild-to-moderate AD in the total Taiwanese population.This was a total population-based case-control study, using the total population of Taiwanese citizens seen in general medical practice; therefore, the findings can be applied to the general population. The study patients were those with newly diagnosed dementia (ICD-9 290.x) and prescribed any acetylcholinesterase inhibitors (AChEI) from the Taiwan National Health Insurance dataset in 1997 to 2008. The newly diagnosed eligible mild-to-moderate AD patients were traced from the dates of their index dates, which was defined as the first day to receive any AChEI treatment, back to 1 year (exposure period) to categorize them into AD with early statin use and without early statin use. Early statin use was defined as patients using statin before AChEI treatment. Alzheimer disease patients with early statin use were those receiving any statin treatment during the exposure period. Then, we used propensity-score-matched strategy to match these 2 groups as 1:1. The matched study patients were followed-up from their index dates. The primary outcome was the discontinuation of AChEI treatment, indicating AD progression.There were 719 mild-to-moderate AD-paired patients with early statin use and without early statin use for analyses. Alzheimer disease progression was statistically lower in AD patients with early statin use than those without (P = 0.00054). After adjusting for other covariates, mild-to-moderate AD patients with early stain use exhibited a 0.85-risk (95% CI = 0.76-0.95, P = 0.0066) to have AD progression than those without.Early statin use was significantly associated with a reduction in AD progression in mild-to-moderate AD patients. The future randomized trial studies can confirm our findings.

Exerkines mitigating Alzheimer's disease progression by regulating inflammation: Focusing on macrophage/microglial NLRP3 inflammasome pathway.