Retinal involvement in Alzheimer's disease (AD): evidence and current progress on the non-invasive diagnosis and monitoring of AD-related pathology using the eye

2020 ◽  
Vol 31 (8) ◽  
pp. 883-904
Author(s):  
Fidelis Chibhabha ◽  
Yang Yaqi ◽  
Feng Li
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Future Research ◽  
Pathological Changes ◽  
Non Invasive ◽  
Impaired Memory ◽  
Age Related ◽  
Cerebral Pathology ◽  
Visual Problems ◽  
The Brain

AbstractAlzheimer's disease (AD) is a common form of age-related dementia that mostly affects the aging population. Clinically, it is a disease characterized by impaired memory and progressive cognitive decline. Although the pathological hallmarks of AD have been traditionally described with a general confinement in the brain, recent studies have shown similar pathological changes in the retina, which is a developmental outgrowth of the forebrain. These AD-related neurodegenerative changes in the retina have been implicated to cause early visual problems in AD even before cognitive impairment becomes apparent. With recent advances in research, the commonly held view that AD-related cerebral pathology causes visual dysfunction through disruption of central visual pathways has been re-examined. Currently, several studies have already explored how AD manifests in the retina and the possibility of using the same retina as a window to non-invasively examine AD-related pathology in the brain. Non-invasive screening of AD through the retina has the potential to improve on early detection and management of the disease since the majority of AD cases are usually diagnosed very late. The purpose of this review is to provide evidence on the involvement of the retina in AD and to suggest a possible direction for future research into the non-invasive screening, diagnosis, and monitoring of AD using the retina.

scholarly journals Promise and Challenge: The Lens Model as a Biomarker for Early Diagnosis of Alzheimer's Disease

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Tian Tian ◽  
Boai Zhang ◽  
Yanjie Jia ◽  
Zhaoming Li
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Diagnosis ◽  
Accurate Diagnosis ◽  
Lens Model ◽  
Non Invasive ◽  
Diagnosis And Prognosis ◽  
Protein Deposits ◽  
Age Related ◽  
The Brain

Alzheimer’s disease (AD) is the most common form of dementia pathologically characterized by cerebral amyloid-beta (Aβ) deposition. Early and accurate diagnosis of the disease still remains a big challenge. There is evidence that Aβaggregation starts to occur years before symptoms arise. Noninvasive monitoring of Aβplaques is critical for both the early diagnosis and prognosis of AD. Presently, there is a major effort on looking for a reasonably priced technology capable of diagnosing AD by detecting the presence of Aβ. Studies suggest that AD is systemic rather than brain-limited focus diseases and the aggregation of the disease-causing proteins also takes place in lens except the brain. There is a possible relationship between AD and a specific subtype of age-related cataract (supranuclear cataract). If similar abnormal protein deposits are present in the lens, it would facilitate non-invasive diagnosis and monitoring of disease progression. However, there are controversies on the issues related to performance and validation of Aβdeposition in lens as biomarkers for early detection of AD. Here we review the recent findings concerning Aβdeposition in the lenses of AD patients and evaluate if the ocular lens can provide a biomarker for AD.

scholarly journals Probable Causes of Alzheimer’s Disease

Sci ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 16
Author(s):  
James David Adams
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Lactic Acid ◽  
Blood Brain Barrier ◽  
Transient Receptor Potential ◽  
Brain Barrier ◽  
Folate Intake ◽  
Blood Brain ◽  
Age Related ◽  
The Brain

A three-part mechanism is proposed for the induction of Alzheimer’s disease: (1) decreased blood lactic acid; (2) increased blood ceramide and adipokines; (3) decreased blood folic acid. The age-related nature of these mechanisms comes from age-associated decreased muscle mass, increased visceral fat and changes in diet. This mechanism also explains why many people do not develop Alzheimer’s disease. Simple changes in lifestyle and diet can prevent Alzheimer’s disease. Alzheimer’s disease is caused by a cascade of events that culminates in damage to the blood–brain barrier and damage to neurons. The blood–brain barrier keeps toxic molecules out of the brain and retains essential molecules in the brain. Lactic acid is a nutrient to the brain and is produced by exercise. Damage to endothelial cells and pericytes by inadequate lactic acid leads to blood–brain barrier damage and brain damage. Inadequate folate intake and oxidative stress induced by activation of transient receptor potential cation channels and endothelial nitric oxide synthase damage the blood–brain barrier. NAD depletion due to inadequate intake of nicotinamide and alterations in the kynurenine pathway damages neurons. Changes in microRNA levels may be the terminal events that cause neuronal death leading to Alzheimer’s disease. A new mechanism of Alzheimer’s disease induction is presented involving lactic acid, ceramide, IL-1β, tumor necrosis factor α, folate, nicotinamide, kynurenine metabolites and microRNA.

scholarly journals Non-invasive in vivo hyperspectral imaging of the retina for potential biomarker use in Alzheimer’s disease

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xavier Hadoux ◽  
Flora Hui ◽  
Jeremiah K. H. Lim ◽  
Colin L. Masters ◽  
Alice Pébay ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Hyperspectral Imaging ◽  
Spectral Difference ◽  
Non Invasive ◽  
Potential Biomarker ◽  
Negative Controls ◽  
The Brain ◽  
Independent Cohort

Abstract Studies of rodent models of Alzheimer’s disease (AD) and of human tissues suggest that the retinal changes that occur in AD, including the accumulation of amyloid beta (Aβ), may serve as surrogate markers of brain Aβ levels. As Aβ has a wavelength-dependent effect on light scatter, we investigate the potential for in vivo retinal hyperspectral imaging to serve as a biomarker of brain Aβ. Significant differences in the retinal reflectance spectra are found between individuals with high Aβ burden on brain PET imaging and mild cognitive impairment (n = 15), and age-matched PET-negative controls (n = 20). Retinal imaging scores are correlated with brain Aβ loads. The findings are validated in an independent cohort, using a second hyperspectral camera. A similar spectral difference is found between control and 5xFAD transgenic mice that accumulate Aβ in the brain and retina. These findings indicate that retinal hyperspectral imaging may predict brain Aβ load.

scholarly journals Osmotin-loaded magnetic nanoparticles with electromagnetic guidance for the treatment of Alzheimer's disease

Nanoscale ◽  
2017 ◽  
Vol 9 (30) ◽  
pp. 10619-10632 ◽  
Author(s):  
Faiz Ul Amin ◽  
Ali Kafash Hoshiar ◽  
Ton Duc Do ◽  
Yeongil Noh ◽  
Shahid Ali Shah ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Magnetic Nanoparticles ◽  
Neurodegenerative Disease ◽  
Amyloid Beta ◽  
Age Related ◽  
Electromagnetic Guidance ◽  
The Brain

Alzheimer's disease (AD) is the most prevalent age-related neurodegenerative disease, pathologically characterized by the accumulation of aggregated amyloid beta (Aβ) in the brain.

scholarly journals Factors associated with brain ageing - a systematic review

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jo Wrigglesworth ◽  
Phillip Ward ◽  
Ian H. Harding ◽  
Dinuli Nilaweera ◽  
Zimu Wu ◽  
...  
Keyword(s):  
Systematic Review ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Community Dwelling ◽  
Systematic Search ◽  
Current Evidence ◽  
Chronological Age ◽  
Future Research ◽  
Age Related ◽  
Brain Ageing

Abstract Background Brain age is a biomarker that predicts chronological age using neuroimaging features. Deviations of this predicted age from chronological age is considered a sign of age-related brain changes, or commonly referred to as brain ageing. The aim of this systematic review is to identify and synthesize the evidence for an association between lifestyle, health factors and diseases in adult populations, with brain ageing. Methods This systematic review was undertaken in accordance with the PRISMA guidelines. A systematic search of Embase and Medline was conducted to identify relevant articles using search terms relating to the prediction of age from neuroimaging data or brain ageing. The tables of two recent review papers on brain ageing were also examined to identify additional articles. Studies were limited to adult humans (aged 18 years and above), from clinical or general populations. Exposures and study design of all types were also considered eligible. Results A systematic search identified 52 studies, which examined brain ageing in clinical and community dwelling adults (mean age between 21 to 78 years, ~ 37% were female). Most research came from studies of individuals diagnosed with schizophrenia or Alzheimer’s disease, or healthy populations that were assessed cognitively. From these studies, psychiatric and neurologic diseases were most commonly associated with accelerated brain ageing, though not all studies drew the same conclusions. Evidence for all other exposures is nascent, and relatively inconsistent. Heterogenous methodologies, or methods of outcome ascertainment, were partly accountable. Conclusion This systematic review summarised the current evidence for an association between genetic, lifestyle, health, or diseases and brain ageing. Overall there is good evidence to suggest schizophrenia and Alzheimer’s disease are associated with accelerated brain ageing. Evidence for all other exposures was mixed or limited. This was mostly due to a lack of independent replication, and inconsistency across studies that were primarily cross sectional in nature. Future research efforts should focus on replicating current findings, using prospective datasets. Trial registration A copy of the review protocol can be accessed through PROSPERO, registration number CRD42020142817.

scholarly journals Elevated age-related cortical iron, ferritin and amyloid plaques in APPswe/PS1ΔE9 transgenic mouse model of Alzheimer’s disease

2019 ◽  
pp. S445-S451 ◽  
Author(s):  
H. Svobodová ◽  
D. Kosnáč ◽  
Z. Balázsiová ◽  
H. Tanila ◽  
P.O. Miettinen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Plaques ◽  
Amyloid Plaque ◽  
Free Iron ◽  
Model Of Alzheimer’S Disease ◽  
Age Related ◽  
Concentration Changes ◽  
The Brain ◽  
Important Marker

Iron is very important element for functioning of the brain. Its concentration changes with aging the brain or during disease. The aim of our work was the histological examination of content of ferritin and free iron (unbound) in brain cortex in association with Aβ plaques from their earliest stages of accumulation in amyloid plaque forming APP/PS1 transgenic mice. Light microscopy revealed the onset of plaques formation at 8-monthage. Detectable traces of free iron and no ferritin were found around plaques at this age, while the rate of their accumulation in and around Aβ plaques was elevated at 13 months of age. Ferritin accumulated mainly on the edge of Aβ plaques, while the smaller amount of free iron was observed in the plaque-free tissue, as well as in and around Aβ plaques. We conclude that free iron and ferritin accumulation follows the amyloid plaques formation. Quantification of cortical iron and ferritin content can be an important marker in the diagnosis of Alzheimer’s disease.

The Mechanical Cause of Age-Related Dementia (Alzheimer's Disease): The Brain is Destroyed by the Pulse

2015 ◽  
Vol 44 (2) ◽  
pp. 355-373 ◽  
Author(s):  
Jonathan Stone ◽  
Daniel M. Johnstone ◽  
John Mitrofanis ◽  
Michael O'Rourke
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Age Related ◽  
The Brain

scholarly journals Non-Invasive RF Technique for Detecting Different Stages of Alzheimer’s Disease and Imaging Beta-Amyloid Plaques and Tau Tangles in the Brain

2020 ◽  
Vol 39 (12) ◽  
pp. 4060-4070
Author(s):  
Imran Saied ◽  
Tughrul Arslan ◽  
Siddharthan Chandran ◽  
Colin Smith ◽  
Tara Spires-Jones ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Plaques ◽  
Beta Amyloid ◽  
Non Invasive ◽  
The Brain

Metabolic syndrome, Alzheimer's disease, and Covid 19: A possible correlation

2021 ◽  
Vol 18 ◽  
Author(s):  
Carmine Finelli
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Metabolic Syndrome ◽  
Current Knowledge ◽  
Future Research ◽  
Breathing Exercises ◽  
Lung Capacity ◽  
Age Related ◽  
Key Indicators ◽  
The Impact

: Age and comorbidities are key indicators of hospital admission, serious illness, and mortality in COVID-19 patients. Patients with age-related comorbidities, such as cardiovascular disease, hypertension, diabetes, chronic kidney disease, NAFLD, obesity, and metabolic syndrome, are more likely to require hospitalization and suffer severe sickness of COVID-19. Patients with Alzheimer’s disease and risk factors associated with dementia may also be more vulnerable to serious COVID-19 infection. Peripheral inflammation, including in patients who recover from illness, may promote the course of neurodegenerative disorders through neuroinflammatory pathways The aim of this study is to examine the impact of COVID-19 on immunity in patients with age-related diseases such as metabolic syndrome and Alzheimer’s disease and also to hypothesize the possible correlation between metabolic syndrome, Alzheimer’s disease, and COVID-19. Identifying the mechanisms that explain the complicated interaction between metabolic syndrome, Alzheimer’s disease, COVID-19, inflammation, and immunity could be crucial to designing effective pharmacological therapies and procedures. This study adds to our basic information about the new coronavirus by synthesizing current knowledge of these linkages. To reduce inflammation and enhance immunity, patients should acquire good lifestyle practices. Walking, breathing exercises, and a nutritious diet all help in improving lung capacity and immunity. Future research into novel therapeutics for patients with metabolic syndrome, Alzheimer’s disease, and COVID-19 inflammation and immunology is encouraged by this paper.

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