Amyloid-β Peptides in Plasma and Cognitive Decline After 1 Year Follow-Up in Alzheimer's Disease Patients

Background: While both cognitive and magnetic resonance imaging (MRI) data has been used to predict progression in Alzheimer’s disease, heterogeneity between patients makes it challenging to predict the rate of cognitive and functional decline for individual subjects. Objective: To investigate prognostic power of MRI-based biomarkers of medial temporal lobe atrophy and macroscopic tissue change to predict cognitive decline in individual patients in clinical trials of early Alzheimer’s disease. Methods: Data used in this study included 312 patients with mild cognitive impairment from the ADNI dataset with baseline MRI, cerebrospinal fluid amyloid-β, cognitive test scores, and a minimum of two-year follow-up information available. We built a prognostic model using baseline cognitive scores and MRI-based features to determine which subjects remain stable and which functionally decline over 2 and 3-year follow-up periods. Results: Combining both sets of features yields 77%accuracy (81%sensitivity and 75%specificity) to predict cognitive decline at 2 years (74%accuracy at 3 years with 75%sensitivity and 73%specificity). When used to select trial participants, this tool yields a 3.8-fold decrease in the required sample size for a 2-year study (2.8-fold decrease for a 3-year study) for a hypothesized 25%treatment effect to reduce cognitive decline. Conclusion: When used in clinical trials for cohort enrichment, this tool could accelerate development of new treatments by significantly increasing statistical power to detect differences in cognitive decline between arms. In addition, detection of future decline can help clinicians improve patient management strategies that will slow or delay symptom progression.

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Amyloid-β misfolding as a plasma biomarker indicates risk for future clinical Alzheimer’s disease in individuals with subjective cognitive decline

Alzheimer s Research & Therapy ◽

10.1186/s13195-020-00738-8 ◽

2020 ◽

Vol 12 (1) ◽

Author(s):

Julia Stockmann ◽

Inge M. W. Verberk ◽

Nina Timmesfeld ◽

Robin Denz ◽

Brian Budde ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Roc Curve ◽

External Validation ◽

Area Under The Curve ◽

Amyloid Β ◽

Sensor Technology ◽

Subjective Cognitive Decline

Abstract Background We evaluated Aβ misfolding in combination with Aβ42/40 ratio as a prognostic tool for future clinical progression to mild cognitive impairment (MCI) or dementia due to Alzheimer’s disease (AD) in individuals with subjective cognitive decline (SCD). Methods Baseline plasma samples (n = 203) from SCD subjects in the SCIENCe project and Amsterdam Dementia Cohort (age 61 ± 9 years; 57% male, mean follow-up time 2.7 years) were analyzed using immuno-infrared-sensor technology. Within 6 years of follow-up, 22 (11%) individuals progressed to MCI or dementia due to AD. Sensor readout values > 1646 cm− 1 reflected normal Aβ folding; readouts at ≤ 1646 cm− 1 reflected low and at < 1644 cm− 1 high misfolding. We used Cox proportional hazard models to quantify Aβ misfolding as a prognostic biomarker for progression to MCI and dementia due to AD. The accuracy of the predicted development of MCI/AD was determined by time-dependent receiver operating characteristic (t-ROC) curve analyses that take individual follow-up and conversion times into account. Statistical models were adjusted for age, sex, and APOEε4 status. Additionally, plasma Aβ42/40 data measured by SIMOA were statistically analyzed and compared. Results All 22 patients who converted to MCI or AD-dementia within 6 years exhibited Aβ misfolding at baseline. Cox analyses revealed a hazard ratio (HR) of 19 (95% confidence interval [CI] 2.2–157.8) for future conversion of SCD subjects with high misfolding and of 11 (95% CI 1.0–110.1) for those with low misfolding. T-ROC curve analyses yielded an area under the curve (AUC) of 0.94 (95% CI 0.86–1.00; 6-year follow-up) for Aβ misfolding in an age, sex, and APOEε4 model. A similar model with plasma Aβ42/40 ratio yielded an AUC of 0.92 (95% CI, 0.82–1.00). The AUC increased to 0.99 (95% CI, 0.99–1.00) after inclusion of both Aβ misfolding and the Aβ42/40 ratio. Conclusions A panel of structure- and concentration-based plasma amyloid biomarkers may predict conversion to clinical MCI and dementia due to AD in cognitively unimpaired subjects. These plasma biomarkers provide a noninvasive and cost-effective alternative for screening early AD pathological changes. Follow-up studies and external validation in larger cohorts are in progress for further validation of our findings.

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Age, vascular disease, and Alzheimer’s disease pathologies in amyloid negative elderly adults

Alzheimer s Research & Therapy ◽

10.1186/s13195-021-00913-5 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Tengfei Guo ◽

Susan M. Landau ◽

William J. Jagust ◽

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Fdg Pet ◽

Amyloid Β ◽

Hippocampal Volume ◽

Factors Associated ◽

Male Sex ◽

The Relationship

Abstract Background We recently reported that CSF phosphorylated tau (p-Tau181) relative to Aβ40 (CSF p-Tau/Aβ40 ratio) was less noisy and increased associations with Alzheimer’s disease (AD) biomarkers compared to CSF p-Tau181 alone. While elevations of CSF p-Tau/Aβ40 can occur in amyloid-β (Aβ) negative (Aβ-) individuals, the factors associated with these elevations and their role in neurodegeneration and cognitive decline are unknown. We aim to explore factors associated with elevated tau in CSF, and how these elevated tau are related to neurodegeneration and cognitive decline in the absence of Aβ positivity. Methods We examined relationships between CSF p-Tau/Aβ40, and CSF Aβ42/Aβ40, Aβ PET, and white matter hyperintensities (WMH) as well as vascular risk factors in 149 cognitively unimpaired and 52 impaired individuals who were presumably not on the Alzheimer’s disease (AD) pathway due to negative Aβ status on both CSF and PET. Subgroups had 18F-fluorodeoxyglucose (FDG) PET and adjusted hippocampal volume (aHCV), and longitudinal measures of CSF, aHCV, FDG PET, and cognition data, so we examined CSF p-Tau/Aβ40 associations with these measures as well. Results Elevated CSF p-Tau/Aβ40 was associated with older age, male sex, greater WMH, and hypertension as well as a pattern of hippocampal atrophy and temporoparietal hypometabolism characteristic of AD. Lower CSF Aβ42/Aβ40, higher WMH, and hypertension but not age, sex, Aβ PET, APOE-ε4 status, body mass index, smoking, and hyperlipidemia at baseline predicted CSF p-Tau/Aβ40 increases over approximately 5 years of follow-up. The relationship between CSF p-Tau/Aβ40 and subsequent cognitive decline was partially or fully explained by neurodegenerative measurements. Conclusions These data provide surprising clues as to the etiology and significance of tau pathology in the absence of Aβ. It seems likely that, in addition to age, both cerebrovascular disease and subthreshold levels of Aβ are related to this tau accumulation. Crucially, this phenotype of CSF tau elevation in amyloid-negative individuals share features with AD such as a pattern of metabolic decline and regional brain atrophy.

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Pharmacogenetics of Angiotensin-Converting Enzyme Inhibitors in Patients with Alzheimer's Disease Dementia

Current Alzheimer Research ◽

10.2174/1567205014666171016101816 ◽

2018 ◽

Vol 15 (4) ◽

pp. 386-398 ◽

Cited By ~ 22

Author(s):

Fabricio Ferreira de Oliveira ◽

Elizabeth Suchi Chen ◽

Marilia Cardoso Smith ◽

Paulo Henrique Ferreira Bertolucci

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Angiotensin Converting Enzyme ◽

Cognitive Decline ◽

Enzyme Inhibitors ◽

Late Onset ◽

Amyloid Β ◽

Converting Enzyme ◽

Converting Enzyme Inhibitors ◽

Alzheimer’S Disease Dementia

Background: While the angiotensin-converting enzyme degrades amyloid-β, angiotensinconverting enzyme inhibitors (ACEis) may slow cognitive decline by way of cholinergic effects, by increasing brain substance P and boosting the activity of neprilysin, and by modulating glucose homeostasis and augmenting the secretion of adipokines to enhance insulin sensitivity in patients with Alzheimer’s disease dementia (AD). We aimed to investigate whether ACE gene polymorphisms rs1800764 and rs4291 are associated with cognitive and functional change in patients with AD, while also taking APOE haplotypes and anti-hypertensive treatment with ACEis into account for stratification. Methods: Consecutive late-onset AD patients were screened with cognitive tests, while their caregivers were queried for functional and caregiver burden scores. Prospective pharmacogenetic correlations were estimated for one year, considering APOE and ACE genotypes and haplotypes, and treatment with ACEis. Results: For 193 patients, minor allele frequencies were 0.497 for rs1800764 – C (44.6% heterozygotes) and 0.345 for rs4291 – T (38.9% heterozygotes), both in Hardy-Weinberg equilibrium. Almost 94% of all patients used cholinesterase inhibitors, while 155 (80.3%) had arterial hypertension, and 124 used ACEis. No functional impacts were found regarding any genotypes or pharmacological treatment. Either for carriers of ACE haplotypes that included rs1800764 – T and rs4291 – A, or for APOE4- carriers of rs1800764 – T or rs4291 – T, ACEis slowed cognitive decline independently of blood pressure variations. APOE4+ carriers were not responsive to treatment with ACEis. Conclusion: ACEis may slow cognitive decline for patients with AD, more remarkably for APOE4- carriers of specific ACE genotypes.

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24(S)-Saringosterol Prevents Cognitive Decline in a Mouse Model for Alzheimer’s Disease

Marine Drugs ◽

10.3390/md19040190 ◽

2021 ◽

Vol 19 (4) ◽

pp. 190

Author(s):

Nikita Martens ◽

Melissa Schepers ◽

Na Zhan ◽

Frank Leijten ◽

Gardi Voortman ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

Cognitive Decline ◽

Inflammatory Marker ◽

Amyloid Β ◽

Liver Fat ◽

Gas Chromatography Mass Spectrometry ◽

Memory Decline ◽

Plaque Load

We recently found that dietary supplementation with the seaweed Sargassum fusiforme, containing the preferential LXRβ-agonist 24(S)-saringosterol, prevented memory decline and reduced amyloid-β (Aβ) deposition in an Alzheimer’s disease (AD) mouse model without inducing hepatic steatosis. Here, we examined the effects of 24(S)-saringosterol as a food additive on cognition and neuropathology in AD mice. Six-month-old male APPswePS1ΔE9 mice and wildtype C57BL/6J littermates received 24(S)-saringosterol (0.5 mg/25 g body weight/day) (APPswePS1ΔE9 n = 20; C57BL/6J n = 19) or vehicle (APPswePS1ΔE9 n = 17; C57BL/6J n = 19) for 10 weeks. Cognition was assessed using object recognition and object location tasks. Sterols were analyzed by gas chromatography/mass spectrometry, Aβ and inflammatory markers by immunohistochemistry, and gene expression by quantitative real-time PCR. Hepatic lipids were quantified after Oil-Red-O staining. Administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice without affecting the Aβ plaque load. Moreover, 24(S)-saringosterol prevented the increase in the inflammatory marker Iba1 in the cortex of APPswePS1ΔE9 mice (p < 0.001). Furthermore, 24(S)-saringosterol did not affect the expression of lipid metabolism-related LXR-response genes in the hippocampus nor the hepatic neutral lipid content. Thus, administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice independent of effects on Aβ load and without adverse effects on liver fat content. The anti-inflammatory effects of 24(S)-saringosterol may contribute to the prevention of cognitive decline.

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Gestational Stress Augments Postpartum β-Amyloid Pathology and Cognitive Decline in a Mouse Model of Alzheimer’s Disease

Cerebral Cortex ◽

10.1093/cercor/bhy251 ◽

2018 ◽

Vol 29 (9) ◽

pp. 3712-3724 ◽

Cited By ~ 5

Author(s):

Zahra Jafari ◽

Jogender Mehla ◽

Bryan E Kolb ◽

Majid H Mohajerani

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Risk Factor ◽

Cognitive Decline ◽

Noise Exposure ◽

Amyloid Β ◽

Control Group ◽

Plaque Size ◽

Model Of Alzheimer’S Disease ◽

Gestational Stress

Abstract Besides well-known risk factors for Alzheimer’s disease (AD), stress, and in particular noise stress (NS), is a lifestyle risk factor common today. It is known that females are at a significantly greater risk of developing AD than males, and given that stress is a common adversity in females during pregnancy, we hypothesized that gestational noise exposure could exacerbate the postpartum development of the AD-like neuropathological changes during the life span. Pregnant APPNL-G-F/NL-G-F mice were randomly assigned to either the stress condition or control group. The stress group was exposed to the NS on gestational days 12–16, which resulted in a markedly higher hypothalamic–pituitary–adrenal (HPA) axis responsivity during the postpartum stage. Higher amyloid-β (Aβ) deposition and larger Aβ plaque size in the olfactory area were the early onset impacts of the gestational stress (GS) seen at the age of 4 months. This pattern of increased Aβ aggregation and larger plaque size were observed in various brain areas involved in both AD and stress regulation, especially in limbic structures, at the age of 6 months. The GS also produced anxiety-like behavior, deficits in learning and memory, and impaired motor coordination. The findings suggest that environmental stresses during pregnancy pose a potential risk factor in accelerating postpartum cognitive decline and AD-like neuropathological changes in the dams (mothers) later in life.

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Smell identification test as a progression marker in Alzheimer's disease

European Psychiatry ◽

10.1016/s0924-9338(11)72209-x ◽

2011 ◽

Vol 26 (S2) ◽

pp. 502-502

Author(s):

L. Velayudhan ◽

M. Pritchard ◽

S. Lovestone

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Late Onset ◽

Linear Regression Analysis ◽

Rapid Progressors ◽

Progression Marker ◽

Identification Test ◽

Smell Identification

IntroductionFactors influencing or predicting progression in Alzheimer's disease (AD) is not well understood. Olfactory dysfunction, impaired smell identification in particular, is known to occur in AD. Mesial temporal lobe, important for memory function is also critical for the processing of olfactory information. In view of the common anatomical substrate, we hypothesized that olfaction dysfunction worsens faster in people with AD with rapid cognitive decline compared to those with slower cognitive decline.AimsTo test whether smell identification test can be used as a predictor for illness progression in AD patients.MethodsForty one participants with late onset mild to moderate AD were recruited from mental health services for older adults. Subjects were classified as ‘Rapid Progressors’ defined on ‘a-priori’ with a loss of 2 or more points in Mini-Mental State Examination (MMSE) within six months. Assessments included MMSE, Neuropsychiatric Inventory, Bristol Activities of Daily Living, and the University of Pennsylvania Smell Identification Test (UPSIT), at baseline and after 3 months.ResultsTwenty subjects were ‘Rapid Progressors’, and had lower UPSIT scores compared to ‘Non-Rapid Progressors’ both at the baseline (p = 0.02) and at follow up after 3 months (p = 0.05). Baseline UPSIT correlated with follow up UPSIT (r = 0.5, p < 0.01) and MMSE (r = 0.4, p = 0.04). Also it was the baseline UPSIT score that best predicted (p < 0.05) the follow up smell and cognitive function on linear regression analysis.ConclusionsSmell identification function could be useful as a clinical measure to assess and predict progression in AD.

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The Trajectory of Cerebrospinal Fluid Growth-Associated Protein 43 in the Alzheimer’s Disease Continuum: A Longitudinal Study

Journal of Alzheimer s Disease ◽

10.3233/jad-215456 ◽

2021 ◽

pp. 1-12

Author(s):

Heng Zhang ◽

Diyang Lyu ◽

Jianping Jia ◽

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cerebrospinal Fluid ◽

Amyloid Β ◽

Dementia Patients ◽

Positron Emission ◽

Potential Biomarker ◽

Synaptic Degeneration ◽

Over Time

Background: Synaptic degeneration has been suggested as an early pathological event that strongly correlates with severity of dementia in Alzheimer’s disease (AD). However, changes in longitudinal cerebrospinal fluid (CSF) growth-associated protein 43 (GAP-43) as a synaptic biomarker in the AD continuum remain unclear. Objective: To assess the trajectory of CSF GAP-43 with AD progression and its association with other AD hallmarks. Methods: CSF GAP-43 was analyzed in 788 participants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI), including 246 cognitively normal (CN) individuals, 415 individuals with mild cognitive impairment (MCI), and 127 with AD dementia based on cognitive assessments. The associations between a multimodal classification scheme with amyloid-β (Aβ), tau, and neurodegeneration, and changes in CSF GAP-43 over time were also analyzed. Results: CSF GAP-43 levels were increased at baseline in MCI and dementia patients, and increased significantly over time in the preclinical (Aβ-positive CN), prodromal (Aβ-positive MCI), and dementia (Aβ-positive dementia) stages of AD. Higher levels of CSF GAP-43 were also associated with higher CSF phosphorylated tau (p-tau) and total tau (t-tau), cerebral amyloid deposition and hypometabolism on positron emission tomography, the hippocampus and middle temporal atrophy, and cognitive performance deterioration at baseline and follow-up. Furthermore, CSF GAP-43 may assist in effectively predicting the probability of dementia onset at 2- or 4-year follow-up. Conclusion: CSF GAP-43 can be used as a potential biomarker associated with synaptic degeneration in subjects with AD; it may also be useful for tracking the disease progression and for monitoring the effects of clinical trials.

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Neurophysiological signatures in Alzheimer’s disease are distinctly associated with TAU, amyloid-β accumulation, and cognitive decline

Science Translational Medicine ◽

10.1126/scitranslmed.aaz4069 ◽

2020 ◽

Vol 12 (534) ◽

pp. eaaz4069 ◽

Cited By ~ 5

Author(s):

Kamalini G. Ranasinghe ◽

Jungho Cha ◽

Leonardo Iaccarino ◽

Leighton B. Hinkley ◽

Alexander J. Beagle ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Decline ◽

Amyloid Β ◽

Tracer Uptake ◽

Therapeutic Approaches ◽

Regional Patterns ◽

Positron Emission ◽

Network Synchrony ◽

Network Disruptions

Neural synchrony is intricately balanced in the normal resting brain but becomes altered in Alzheimer’s disease (AD). To determine the neurophysiological manifestations associated with molecular biomarkers of AD neuropathology, in patients with AD, we used magnetoencephalographic imaging (MEGI) and positron emission tomography with amyloid-beta (Aβ) and TAU tracers. We found that alpha oscillations (8 to 12 Hz) were hyposynchronous in occipital and posterior temporoparietal cortices, whereas delta-theta oscillations (2 to 8 Hz) were hypersynchronous in frontal and anterior temporoparietal cortices, in patients with AD compared to age-matched controls. Regional patterns of alpha hyposynchrony were unique in each neurobehavioral phenotype of AD, whereas the regional patterns of delta-theta hypersynchrony were similar across the phenotypes. Alpha hyposynchrony strongly colocalized with TAU deposition and was modulated by the degree of TAU tracer uptake. In contrast, delta-theta hypersynchrony colocalized with both TAU and Aβ depositions and was modulated by both TAU and Aβ tracer uptake. Furthermore, alpha hyposynchrony but not delta-theta hypersynchrony was correlated with the degree of global cognitive dysfunction in patients with AD. The current study demonstrates frequency-specific neurophysiological signatures of AD pathophysiology and suggests that neurophysiological measures from MEGI are sensitive indices of network disruptions mediated by TAU and Aβ and associated cognitive decline. These findings facilitate the pursuit of novel therapeutic approaches toward normalizing network synchrony in AD.

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Midlife physical activity is associated with lower incidence of vascular dementia but not Alzheimer’s disease

Alzheimer s Research & Therapy ◽

10.1186/s13195-019-0538-4 ◽

2019 ◽

Vol 11 (1) ◽

Cited By ~ 3

Author(s):

Oskar Hansson ◽

Martina Svensson ◽

Anna-Märta Gustavsson ◽

Emelie Andersson ◽

Yiyi Yang ◽

...

Keyword(s):

Physical Activity ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Vascular Dementia ◽

Lower Incidence ◽

Amyloid Β ◽

Synaptic Proteins ◽

Cancer Study ◽

Diet And Cancer

Abstract Background Physical activity might reduce the risk of developing dementia. However, it is still unclear whether the protective effect differs depending on the subtype of dementia. We aimed to investigate if midlife physical activity affects the development of vascular dementia (VaD) and Alzheimer’s disease (AD) differently in two large study populations with different designs. Methods Using a prospective observational design, we studied whether long-distance skiers of the Swedish Vasaloppet (n = 197,685) exhibited reduced incidence of VaD or AD compared to matched individuals from the general population (n = 197,684) during 21 years of follow-up (median 10, interquartile range (IQR) 5–15 years). Next, we studied the association between self-reported physical activity, stated twice 5 years apart, and incident VaD and AD in 20,639 participants in the Swedish population-based Malmo Diet and Cancer Study during 18 years of follow-up (median 15, IQR 14–17 years). Finally, we used a mouse model of AD and studied brain levels of amyloid-β, synaptic proteins, and cognitive function following 6 months of voluntary wheel running. Results Vasaloppet skiers (median age 36.0 years [IQR 29.0–46.0], 38% women) had lower incidence of all-cause dementia (adjusted hazard ratio (HR) 0.63, 95% CI 0.52–0.75) and VaD (adjusted HR 0.49, 95% CI 0.33–0.73), but not AD, compared to non-skiers. Further, faster skiers exhibited a reduced incidence of VaD (adjusted HR 0.38, 95% CI 0.16–0.95), but not AD or all-cause dementia compared to slower skiers. In the Malmo Diet and Cancer Study (median age 57.5 years [IQR 51.0–63.8], 60% women), higher physical activity was associated with reduced incidence of VaD (adjusted HR 0.65, 95% CI 0.49-0.87), but not AD nor all-cause dementia. These findings were also independent of APOE-ε4 genotype. In AD mice, voluntary running did not improve memory, amyloid-β, or synaptic proteins. Conclusions Our results indicate that physical activity in midlife is associated with lower incidence of VaD. Using three different study designs, we found no significant association between physical activity and subsequent development of AD.

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