Retina in Health and Disease

Editor


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Collection Editor
1. School of Optometry, University of Montreal, Montreal, QC, Canada
2. Department of Neurology and Neurosurgery, The Montreal Neurological Institute, McGill University, Montreal, QC, Canada
3. Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
Interests: visual system; retina; lateral geniculate nucleus; endocannabinoids; blindness; humans; monkeys; histology; immunohistochemistry
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

Dear Colleagues,

Vision is the most important sense in higher mammals. The retina is the first step in visual processing and is the window to the brain. It is not surprising that problems arising in the retina would lead to moderate to severe visual impairments. According to the World Health Organization, 1.2 billion people suffer from visual impairments and blindness. Moreover, people live longer, and many retinal diseases become more frequent. New advances in retina research offer hope to cure many of these illnesses. For example, in recent years, the endocannabinoid system, present in the retina, has become an interesting therapeutic target. Other new approaches (e.g., stem cell therapy) and technological advances (e.g., retinal implants) are underway to cure these diseases. Of course, to understand pathology, one must know about the normal retina. In this issue, we would like to present up-to-date advances on the healthy retina (e.g., anatomy, physiology, molecular biology), as well as common retinal diseases and pharmacological treatments.

Potential topics include but are not limited to:

  • Normal retinal development in animal and human models
  • Functionals aspects: physiology and perception (color and form perception, single unit physiology and electroretinography)
  • From photoreceptors to vision and perception
  • The endocannabinoid system in the normal retina: expression, localization, and function
  • Role of the endocannabinoid system in development
  • Retinal genetics
  • Retinal pathologies: AMD, glaucoma, neurovascular diseases, color blindness, genetic diseases (Lieber Amaurosis), perceptual anomalies, illusions, hallucinations (Charles Bonnet syndrome).

Prof. Dr. Maurice Ptito
Collection Editor

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Related Special Issue

Published Papers (5 papers)

2022

14 pages, 3352 KiB  
Article
Surgical Menopause Impairs Retinal Conductivity and Worsens Prognosis in an Acute Model of Rat Optic Neuropathy
by Edyta Olakowska, Piotr Rodak, Anna Pacwa, Joanna Machowicz, Bartosz Machna, Joanna Lewin-Kowalik and Adrian Smedowski
Cells 2022, 11(19), 3062; https://doi.org/10.3390/cells11193062 - 29 Sep 2022
Cited by 4 | Viewed by 1882
Abstract
Deficiency of estradiol during the menopausal period is an important risk factor for neurodegenerative diseases, including various optic neuropathies. The aim of this study was to evaluate the impact of surgical menopause on the function and survival ratio of RGCs in the rat [...] Read more.
Deficiency of estradiol during the menopausal period is an important risk factor for neurodegenerative diseases, including various optic neuropathies. The aim of this study was to evaluate the impact of surgical menopause on the function and survival ratio of RGCs in the rat model of ONC (optic nerve crush). We used eight-week-old female Long Evans rats, divided into two main groups depending on the time between ovariectomy procedure (OVA) and euthanasia (two weeks vs. seven weeks), and subgroups—OVA, OVA + ONC, or ONC. Retinal function was assessed with electroretinography (ERG). RGC loss ratio was evaluated using immunolabelling and counting of RGCs. Seven weeks after OVA, the menopause morphologically affected interneurons but not RGC; however, when the ONC procedure was applied, RGCs appeared to be more susceptible to damage in case of deprivation of estrogens. In our analysis, PhNR (photopic negative responses) were severely diminished in the OVA + ONC group. A deprivation of estrogens in menopause results in accelerated retinal neurodegeneration that firstly involves retinal interneurons. The lack of estrogens increases the susceptibility of RGCs to insults. Full article
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12 pages, 1563 KiB  
Article
Age and Sex-Related Changes in Retinal Function in the Vervet Monkey
by Catarina Micaelo-Fernandes, Joseph Bouskila, Roberta M. Palmour, Jean-François Bouchard and Maurice Ptito
Cells 2022, 11(17), 2751; https://doi.org/10.3390/cells11172751 - 3 Sep 2022
Cited by 1 | Viewed by 2061
Abstract
Among the deficits in visual processing that accompany healthy aging, the earliest originate in the retina. Moreover, sex-related differences in retinal function have been increasingly recognized. To better understand the dynamics of the retinal aging trajectory, we used the light-adapted flicker electroretinogram (ERG) [...] Read more.
Among the deficits in visual processing that accompany healthy aging, the earliest originate in the retina. Moreover, sex-related differences in retinal function have been increasingly recognized. To better understand the dynamics of the retinal aging trajectory, we used the light-adapted flicker electroretinogram (ERG) to functionally assess the state of the neuroretina in a large cohort of age- and sex-matched vervet monkeys (N = 35), aged 9 to 28 years old, with no signs of obvious ocular pathology. We primarily isolated the cone–bipolar axis by stimulating the retina with a standard intensity light flash (2.57 cd/s/m2) at eight different frequencies, ranging from 5 to 40 Hz. Sex-specific changes in the voltage and temporal characteristics of the flicker waveform were found in older individuals (21–28 years-old, N = 16), when compared to younger monkeys (9–20 years-old, N = 19), across all stimulus frequencies tested. Specifically, significantly prolonged implicit times were observed in older monkeys (p < 0.05), but a significant reduction of the amplitude of the response was only found in old male monkeys (p < 0.05). These changes might reflect ongoing degenerative processes targeting the retinal circuitry and the cone subsystem in particular. Altogether, our findings corroborate the existing literature in humans and other species, where aging detrimentally affects photopic retinal responses, and draw attention to the potential contribution of different hormonal environments. Full article
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20 pages, 1466 KiB  
Article
High-Fat Diet Alters the Retinal Pigment Epithelium and Choroidal Transcriptome in the Absence of Gut Microbiota
by Jason Xiao, Bingqing Xie, David Dao, Melanie Spedale, Mark D’Souza, Betty Theriault, Seenu M. Hariprasad, Dinanath Sulakhe, Eugene B. Chang and Dimitra Skondra
Cells 2022, 11(13), 2076; https://doi.org/10.3390/cells11132076 - 30 Jun 2022
Cited by 4 | Viewed by 2804
Abstract
Relationships between retinal disease, diet, and the gut microbiome have started to emerge. In particular, high-fat diets (HFDs) are associated with the prevalence and progression of several retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR). These effects are thought to [...] Read more.
Relationships between retinal disease, diet, and the gut microbiome have started to emerge. In particular, high-fat diets (HFDs) are associated with the prevalence and progression of several retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR). These effects are thought to be partly mediated by the gut microbiome, which modulates interactions between diet and host homeostasis. Nevertheless, the effects of HFDs on the retina and adjacent retinal pigment epithelium (RPE) and choroid at the transcriptional level, independent of gut microbiota, are not well-understood. In this study, we performed the high-throughput RNA-sequencing of germ-free (GF) mice to explore the transcriptional changes induced by HFD in the RPE/choroid. After filtering and cleaning the data, 649 differentially expressed genes (DEGs) were identified, with 616 genes transcriptionally upregulated and 33 genes downregulated by HFD compared to a normal diet (ND). Enrichment analysis for gene ontology (GO) using the DEGs was performed to analyze over-represented biological processes in the RPE/choroid of GF-HFD mice relative to GF-ND mice. GO analysis revealed the upregulation of processes related to angiogenesis, immune response, and the inflammatory response. Additionally, molecular functions that were altered involved extracellular matrix (ECM) binding, ECM structural constituents, and heparin binding. This study demonstrates novel data showing that HFDs can alter RPE/choroid tissue transcription in the absence of the gut microbiome. Full article
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10 pages, 2926 KiB  
Article
Computerized Texture Analysis of Optical Coherence Tomography Angiography of Choriocapillaris in Normal Eyes of Young and Healthy Subjects
by Asadolah Movahedan, Phillip Vargas, John Moir, Gabriel Kaufmann, Lindsay Chun, Claire Smith, Nathalie Massamba, Patrick La Riviere and Dimitra Skondra
Cells 2022, 11(12), 1934; https://doi.org/10.3390/cells11121934 - 15 Jun 2022
Cited by 2 | Viewed by 2265
Abstract
Computerized texture analysis uses higher-order mathematics to identify patterns beyond what the naked eye can recognize. We tested its feasibility in optical coherence tomography angiography imaging of choriocapillaris. Our objective was to determine sets of parameters that provide coherent and consistent output when [...] Read more.
Computerized texture analysis uses higher-order mathematics to identify patterns beyond what the naked eye can recognize. We tested its feasibility in optical coherence tomography angiography imaging of choriocapillaris. Our objective was to determine sets of parameters that provide coherent and consistent output when applied to a homogeneous, healthy group of patients. This observational cross-sectional study involved 19 eyes of 10 young and healthy Caucasian subjects. En-face macular optical coherence tomography angiography of superficial choriocapillaris was obtained by the RTVue-XR Avanti system. Various algorithms were used to extract texture features. The mean and standard deviation were used to assess the distribution and dispersion of data points in each metric among eyes, which included: average gray level, gray level yielding 70% threshold and 30% threshold, balance, skewness, energy, entropy, contrast, edge mean gradient, root-mean-square variation, and first moment of power spectrum, which was compared between images, showing a highly concordant homology between all eyes of participants. We conclude that computerized texture analysis for en-face optical coherence tomography angiography images of choriocapillaris is feasible and provides values that are coherent and tightly distributed around the mean in a homogenous, healthy group of patients. Homology of blob size among subjects may represent a “repeat pattern” in signal density and thus a perfusion in the superficial choriocapillaris of healthy young individuals of the same ethnic background. Full article
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10 pages, 1611 KiB  
Review
Role of Damage-Associated Molecular Patterns (DAMPs/Alarmins) in Severe Ocular Allergic Diseases
by Ken Fukuda, Waka Ishida, Tatsuma Kishimoto, Isana Nakajima, Yusaku Miura, Tamaki Sumi and Kenji Yamashiro
Cells 2022, 11(6), 1051; https://doi.org/10.3390/cells11061051 - 20 Mar 2022
Cited by 6 | Viewed by 3009
Abstract
Severe ocular allergic diseases, such as atopic keratoconjunctivitis and vernal keratoconjunctivitis, cause severe allergic inflammation in the conjunctiva and corneal epithelial damage, resulting in visual disturbances. The involvement of damage (danger)-associated molecular patterns (DAMPs/alarmins) in the pathogenesis of these diseases has been recognized. [...] Read more.
Severe ocular allergic diseases, such as atopic keratoconjunctivitis and vernal keratoconjunctivitis, cause severe allergic inflammation in the conjunctiva and corneal epithelial damage, resulting in visual disturbances. The involvement of damage (danger)-associated molecular patterns (DAMPs/alarmins) in the pathogenesis of these diseases has been recognized. Alarmins released from damaged corneal epithelial cells or eosinophils play a critical role in the induction of corneal lesions, vicious loop of corneal injury, and exacerbation of conjunctival allergic inflammation. Alarmins in the conjunctiva also play an essential role in the development of both allergic inflammation, based on the acquired immune system, and type 2 inflammation by innate immune responses in the ocular surface. Therefore, alarmins may be a potentially important therapeutic target in severe refractory ocular allergic diseases. Full article
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