scholarly journals Advances in retina imaging as potential biomarkers for early diagnosis of Alzheimer’s disease

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ying Zhang ◽  
Yanjiang Wang ◽  
Ce Shi ◽  
Meixiao Shen ◽  
Fan Lu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Optical Coherence Tomography ◽  
Early Diagnosis ◽  
Optical Coherence ◽  
Social Burden ◽  
Microvascular Changes ◽  
Preclinical Ad ◽  
The Brain ◽  
Potential Biomarkers

AbstractAs the most common form of dementia, Alzheimer’s disease (AD) is characterized by progressive cognitive impairments and constitutes a major social burden. Currently, the invasiveness and high costs of tests have limited the early detection and intervention of the disease. As a unique window of the brain, retinal changes can reflect the pathology of the brain. In this review, we summarize current understanding of retinal structures in AD, mild cognitive impairment (MCI) and preclinical AD, focusing on neurodegeneration and microvascular changes measured using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) technologies. The literature suggests that the impairment of retinal microvascular network and neural microstructure exists in AD, MCI and even preclinical AD. These findings provide valuable insights into a better understanding of disease pathogenesis and demonstrate that retinal changes are potential biomarkers for early diagnosis of AD and monitoring of disease progression.

scholarly journals Optical coherence tomography angiography in preclinical Alzheimer’s disease

2019 ◽  
Vol 104 (2) ◽  
pp. 157-161 ◽  
Author(s):  
Jacoba Alida van de Kreeke ◽  
Hoang-Ton Nguyen ◽  
Elles Konijnenberg ◽  
Jori Tomassen ◽  
Anouk den Braber ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Optical Coherence Tomography ◽  
Optical Coherence Tomography Angiography ◽  
Vessel Density ◽  
Binding Potential ◽  
Continuous Measure ◽  
Optical Coherence ◽  
Mz Twins ◽  
The Brain

Background/aimsAs a protrusion from the brain, the retina might reflect the status of the brain. Previous studies showed a decrease in vessel density and foveal avascular zone (FAZ) enlargement on optical coherence tomography angiography (OCTA) in individuals suffering from Alzheimer’s disease (AD). This study aims to assess whether such changes are already present in preclinical stages of AD, in a population of monozygotic (MZ) twins.Methods124 cognitively healthy individuals (MZ twins, ages 60–93 years) underwent [18F]flutemetamol amyloid positron emission tomography (PET) scanning and OCTA. PET scans were visually rated for cortical amyloid-beta (Aβ) positivity. Parametric global cortical non-displaceable binding potential (BPND) was used as a continuous measure for Aβ aggregation. FAZ size and vessel densities for the inner and outer ring of the macular ETDRS grid and in a 3–6 mm ring around the optic nerve head (ONH) were measured.OCTA measures were associated with visual Aβ score,BPNDand amyloid load estimated by twin concordance on visual Aβ score. Twin correlations were estimated as a measure of maximum heritability of OCTA measures.Results13 of 124 participants were Aβ+. Aβ+ individuals had significantly higher vessel density than Aβ– individuals in all regions but did not differ in FAZ size. Twin analyses showed a positive association between and vessel densities in all regions.BPNDtended to be associated with higher vessel density in the inner ring. Twin correlations were moderate/high for all OCTA parameters except vessel density around the ONH, which correlated weakly.ConclusionRetinal vessel density was higher in individuals with preclinical AD.

scholarly journals Magnetic Nanoparticles as In Vivo Tracers for Alzheimer’s Disease

2020 ◽  
Vol 6 (1) ◽  
pp. 13
Author(s):  
Bhargy Sharma ◽  
Konstantin Pervushin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Diagnosis ◽  
Contrast Agents ◽  
Neurological Diseases ◽  
Pulse Sequences ◽  
Experimental Conditions ◽  
Magnetic Resonance Imaging Mri ◽  
The Brain

Drug formulations and suitable methods for their detection play a very crucial role in the development of therapeutics towards degenerative neurological diseases. For diseases such as Alzheimer’s disease, magnetic resonance imaging (MRI) is a non-invasive clinical technique suitable for early diagnosis. In this review, we will discuss the different experimental conditions which can push MRI as the technique of choice and the gold standard for early diagnosis of Alzheimer’s disease. Here, we describe and compare various techniques for administration of nanoparticles targeted to the brain and suitable formulations of nanoparticles for use as magnetically active therapeutic probes in drug delivery targeting the brain. We explore different physiological pathways involved in the transport of such nanoparticles for successful entry in the brain. In our lab, we have used different formulations of iron oxide nanoparticles (IONPs) and protein nanocages as contrast agents in anatomical MRI of an Alzheimer’s disease (AD) brain. We compare these coatings and their benefits to provide the best contrast in addition to biocompatibility properties to be used as sustainable drug-release systems. In the later sections, the contrast enhancement techniques in MRI studies are discussed. Examples of contrast-enhanced imaging using advanced pulse sequences are discussed with the main focus on important studies in the field of neurological diseases. In addition, T1 contrast agents such as gadolinium chelates are compared with the T2 contrast agents mainly made of superparamagnetic inorganic metal nanoparticles.

Sign in / Sign up

Export Citation Format

Share Document