Characterization of Retinal Drusen in Subjects at High Genetic Risk of Developing Sporadic Alzheimer’s Disease: An Exploratory Analysis

López‐Cuenca, Inés; Salobrar‐García, Elena; Gil-Salgado, Inés; Sánchez-Puebla, Lídia; Elvira‐Hurtado, Lorena; Fernández‐Albarral, José A.; Ramírez‐Toraño, Federico; Barabash, Ana; Frutos-Lucas, Jaisalmer de; Salazar, Juan J.; Ramı́rez, José M.; Hoz, Rosa de

doi:10.3390/jpm12050847

Cited by 5 publications

(7 citation statements)

References 48 publications

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“…Also, retinal amyloid/inclusion bodies indicated in AD [ 72 , 73 ] are also found in retinal drusenoid structures in age-related macular degeneration (AMD) [ 74 ]. It must however be noted that other studies have found no association between a family history of AD/APOE e4 genotype and the presence of drusen, and that amyloid deposits are distinct from drusenoid structures [ 72 , 75 ]. Without a multimodal imaging model of blue autofluorescence imaging, color fundus, and spectral domain OCT, drusenoid structures in AMD may be falsely counted as retinal amyloid or inclusion bodies.…”

Section: Discussionmentioning

confidence: 99%

Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer’s disease

Arthur,

Ravichandran,

Snyder

et al. 2023

Alz Res Therapy

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Background Compared to standard neuro-diagnostic techniques, retinal biomarkers provide a probable low-cost and non-invasive alternative for early Alzheimer’s disease (AD) risk screening. We have previously quantified the periarteriole and perivenule capillary free zones (mid-peripheral CFZs) in cognitively unimpaired (CU) young and older adults as novel metrics of retinal tissue oxygenation. There is a breakdown of the inner retinal blood barrier, pericyte loss, and capillary non-perfusion or dropout in AD leading to potential enlargement of the mid-peripheral CFZs. We hypothesized the mid-peripheral CFZs will be enlarged in CU older adults at high risk for AD compared to low-risk individuals. Methods 20 × 20° optical coherence tomography angiography images consisting of 512 b-scans, 512 A-scans per b-scan, 12-µm spacing between b-scans, and 5 frames averaged per each b-scan location of the central fovea and of paired major arterioles and venules with their surrounding capillaries inferior to the fovea of 57 eyes of 37 CU low-risk (mean age: 66 years) and 50 eyes of 38 CU high-risk older adults (mean age: 64 years; p = 0.24) were involved in this study. High-risk participants were defined as having at least one APOE e4 allele and a positive first-degree family history of AD while low-risk participants had neither of the two criteria. All participants had Montreal Cognitive Assessment scores ≥ 26. The mid-peripheral CFZs were computed in MATLAB and compared between the two groups. Results The periarteriole CFZ of the high-risk group (75.8 ± 9.19 µm) was significantly larger than that of the low-risk group (71.3 ± 7.07 µm), p = 0.005, Cohen’s d = 0.55. The perivenule CFZ of the high-risk group (60.4 ± 8.55 µm) was also significantly larger than that of the low-risk group (57.3 ± 6.40 µm), p = 0.034, Cohen’s d = 0.42. There were no significant differences in foveal avascular zone (FAZ) size, FAZ effective diameter, and vessel density between the two groups, all p > 0.05. Conclusions Our results show larger mid-peripheral CFZs in CU older adults at high risk for AD, with the potential for the periarteriole CFZ to serve as a novel retinal vascular biomarker for early AD risk detection.

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Section: Discussionmentioning

confidence: 99%

Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer’s disease

Arthur,

Ravichandran,

Snyder

et al. 2023

Alz Res Therapy

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“…AMD is associated with the accumulation of degenerative material called drusen between the RPE and its basement membrane, eventually leading to a degeneration of overlying photoreceptors. Pathological examination of drusen has shown the presence of Aβ protein, suggesting a link with AD [17,18]. Glaucoma is a progressive ocular condition characterized by loss of RGC and thinning of its axons, the retinal nerve fiber layer (RNFL) of the retina.…”

Section: Ad Macular Degeneration and Glaucoma: Common Pathogenetic Me...mentioning

confidence: 99%

“…Sustained elevation of IOP leads to slowing of axonal conduction within RNFL, causing accumulation of Aβ and p-tau in RGCs, resulting in neuronal degeneration. Loss of RGC leads to axonal loss, thinning of RNFL, and optic atrophy, which leads to blindness [18,19].…”

Section: Ad Macular Degeneration and Glaucoma: Common Pathogenetic Me...mentioning

confidence: 99%

Eye as a window to the brain: Review of retinal changes in Alzheimer’s dementia

Sastry

Keshavamurthy²

2022

J Stud Res

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Alzheimer's disease (AD) is the most common neurodegenerative disease causing significant morbidity and mortality in the elderly, affecting million worldwide. Diagnosis of AD is mainly by clinical symptoms, use of tests to detect loss of higher mental functions, and confirmed by neuroimaging studies such as magnetic resonance imaging and positron emission tomography. Current research in AD aims at early detection of pathological changes in the brain and development of disease-modifying drugs. Testing the effectiveness of these drugs requires the development of a noninvasive and cost-effective screening tool. Retinal changes in patients with AD mirror those found in the brain and offers a window for early detection of AD before cognitive changes set it. This article reviews the pathological correlation between retinal changes and AD and the current advances in retinal imaging to detect AD.

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“…Abnormalities on OCTA images usually indicate the presence of a number of diseases, such as early glaucomatous optic neuropathy [1], diabetic retinopathy [2], and age-related macular degeneration [3]. Some other recent studies have shown that deep microvascular morphological changes revealed by OCTA images are associated with Alzheimer's disease [4] and mild cognitive impairment [5]. This opens up new ideas to investigate the relationship between abnormalities in retinal vessels and various neurodegenerative diseases.…”

Section: Introductionmentioning

confidence: 97%

“…Mse loss 3. Mse loss + contrastive loss 4. Mse loss + contrastive loss + image augmentation (CLANE) 5.…”

mentioning

confidence: 99%

Retinal OCTA Image Segmentation Based on Global Contrastive Learning

Feng

Wang

et al. 2022

Sensors

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The automatic segmentation of retinal vessels is of great significance for the analysis and diagnosis of retinal related diseases. However, the imbalanced data in retinal vascular images remain a great challenge. Current image segmentation methods based on deep learning almost always focus on local information in a single image while ignoring the global information of the entire dataset. To solve the problem of data imbalance in optical coherence tomography angiography (OCTA) datasets, this paper proposes a medical image segmentation method (contrastive OCTA segmentation net, COSNet) based on global contrastive learning. First, the feature extraction module extracts the features of OCTA image input and maps them to the segment head and the multilayer perceptron (MLP) head, respectively. Second, a contrastive learning module saves the pixel queue and pixel embedding of each category in the feature map into the memory bank, generates sample pairs through a mixed sampling strategy to construct a new contrastive loss function, and forces the network to learn local information and global information simultaneously. Finally, the segmented image is fine tuned to restore positional information of deep vessels. The experimental results show the proposed method can improve the accuracy (ACC), the area under the curve (AUC), and other evaluation indexes of image segmentation compared with the existing methods. This method could accomplish segmentation tasks in imbalanced data and extend to other segmentation tasks.

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Characterization of Retinal Drusen in Subjects at High Genetic Risk of Developing Sporadic Alzheimer’s Disease: An Exploratory Analysis

Cited by 5 publications

References 48 publications

Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer’s disease

Retinal mid-peripheral capillary free zones are enlarged in cognitively unimpaired older adults at high risk for Alzheimer’s disease

Eye as a window to the brain: Review of retinal changes in Alzheimer’s dementia

Retinal OCTA Image Segmentation Based on Global Contrastive Learning

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