scholarly journals Retinal Macroglial Responses in Health and Disease

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Rosa de Hoz ◽  
Blanca Rojas ◽  
Ana I. Ramírez ◽  
Juan J. Salazar ◽  
Beatriz I. Gallego ◽  
...  
Keyword(s):  
Age Related Macular Degeneration ◽  
Reactive Gliosis ◽  
Blood Retinal Barrier ◽  
Waste Products ◽  
Physical Support ◽  
Age Related ◽  
Close Proximity ◽  
Health And Disease ◽  
Extracellular Ions ◽  
Retinal Pathologies

Due to their permanent and close proximity to neurons, glial cells perform essential tasks for the normal physiology of the retina. Astrocytes and Müller cells (retinal macroglia) provide physical support to neurons and supplement them with several metabolites and growth factors. Macroglia are involved in maintaining the homeostasis of extracellular ions and neurotransmitters, are essential for information processing in neural circuits, participate in retinal glucose metabolism and in removing metabolic waste products, regulate local blood flow, induce the blood-retinal barrier (BRB), play fundamental roles in local immune response, and protect neurons from oxidative damage. In response to polyetiological insults, glia cells react with a process called reactive gliosis, seeking to maintain retinal homeostasis. When malfunctioning, macroglial cells can become primary pathogenic elements. A reactive gliosis has been described in different retinal pathologies, including age-related macular degeneration (AMD), diabetes, glaucoma, retinal detachment, or retinitis pigmentosa. A better understanding of the dual, neuroprotective, or cytotoxic effect of macroglial involvement in retinal pathologies would help in treating the physiopathology of these diseases. The extensive participation of the macroglia in retinal diseases points to these cells as innovative targets for new drug therapies.

Ocular Carotenoid Status in Health and Disease

2019 ◽  
Vol 39 (1) ◽  
pp. 95-120 ◽  
Author(s):  
Lydia Sauer ◽  
Binxing Li ◽  
Paul S. Bernstein
Keyword(s):  
Macular Degeneration ◽  
Age Related Macular Degeneration ◽  
Retinal Diseases ◽  
Light Damage ◽  
Nutritional Interventions ◽  
Age Related ◽  
Dietary Nutrients ◽  
Health And Disease ◽  
Noninvasive Assessment ◽  
Retinal Pathologies

Retinal carotenoids are dietary nutrients that uniquely protect the eye from light damage and various retinal pathologies. Their antioxidative properties protect the eye from many retinal diseases, such as age-related macular degeneration. As many retinal diseases are accompanied by low carotenoid levels, accurate noninvasive assessment of carotenoid status can help ophthalmologists identify the patients most likely to benefit from carotenoid supplementation. This review focuses on the different methods available to assess carotenoid status and highlights disease-related changes and potential nutritional interventions.

scholarly journals The Impact of Oxidative Stress on Blood-Retinal Barrier Physiology in Age-Related Macular Degeneration

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Annamaria Tisi ◽  
Marco Feligioni ◽  
Maurizio Passacantando ◽  
Marco Ciancaglini ◽  
Rita Maccarone
Keyword(s):  
Oxidative Stress ◽  
Macular Degeneration ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Age Related Macular Degeneration ◽  
Blood Retinal Barrier ◽  
Functional Changes ◽  
Beneficial Effects ◽  
Age Related ◽  
The Impact

The blood retinal barrier (BRB) is a fundamental eye component, whose function is to select the flow of molecules from the blood to the retina and vice-versa, and its integrity allows the maintenance of a finely regulated microenvironment. The outer BRB, composed by the choriocapillaris, the Bruch’s membrane, and the retinal pigment epithelium, undergoes structural and functional changes in age-related macular degeneration (AMD), the leading cause of blindness worldwide. BRB alterations lead to retinal dysfunction and neurodegeneration. Several risk factors have been associated with AMD onset in the past decades and oxidative stress is widely recognized as a key factor, even if the exact AMD pathophysiology has not been exactly elucidated yet. The present review describes the BRB physiology, the BRB changes occurring in AMD, the role of oxidative stress in AMD with a focus on the outer BRB structures. Moreover, we propose the use of cerium oxide nanoparticles as a new powerful anti-oxidant agent to combat AMD, based on the relevant existing data which demonstrated their beneficial effects in protecting the outer BRB in animal models of AMD.

scholarly journals Improving Efficiency in Separating Blood Vessels from Retinal Images with Deep Learning Techniques

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3637-3640
Keyword(s):  
Diabetic Retinopathy ◽  
Deep Learning ◽  
Macular Degeneration ◽  
Blood Vessels ◽  
Age Related Macular Degeneration ◽  
Retinal Images ◽  
Retinal Vessels ◽  
Age Related ◽  
Learning Techniques ◽  
Retinal Pathologies

Retinal vessels ID means to isolate the distinctive retinal configuration issues, either wide or restricted from fundus picture foundation, for example, optic circle, macula, and unusual sores. Retinal vessels recognizable proof investigations are drawing in increasingly more consideration today because of pivotal data contained in structure which is helpful for the identification and analysis of an assortment of retinal pathologies included yet not restricted to: Diabetic Retinopathy (DR), glaucoma, hypertension, and Age-related Macular Degeneration (AMD). With the advancement of right around two decades, the inventive methodologies applying PC supported systems for portioning retinal vessels winding up increasingly significant and coming nearer. Various kinds of retinal vessels segmentation strategies discussed by using Deep Learning methods. At that point, the pre-processing activities and the best in class strategies for retinal vessels distinguishing proof are presented.

Intraocular exosomes in eye diseases

2021 ◽  
Vol 21 ◽  
Author(s):  
Hui Zhang ◽  
Xiaomin Zhang ◽  
Xiaorong Li
Keyword(s):  
Messenger Rna ◽  
Biological Fluids ◽  
Eye Diseases ◽  
Age Related Macular Degeneration ◽  
Pathological State ◽  
Barrier Dysfunction ◽  
Blood Retinal Barrier ◽  
Ecm Remodeling ◽  
Age Related ◽  
Eye Tissues

: Exosomes, nanosized extracellular vesicles with a size of 30–150nm, contain many biological materials, such as messenger RNA (mRNA), microRNA (miRNA), proteins, and transcription factors. It has been identified in all biological fluids and recognized as an important part of intercellular communication. While the role of exosomes in cancer has been studied in-depth, our understanding of their relevance for ocular tissues has just begun to evolve. Intraocular fluids, including aqueous humor and vitreous humor, play a role in nourishing eye tissues and in expelling metabolites. In the pathological state, intraocular exosomes can mediate pathological processes such as ECM remodeling, retinal inflammation, and blood-retinal barrier dysfunction. Herein, we reviewed the latest advances of intraocular exosomes in the research of several eye diseases, including glaucoma, age-related macular degeneration, myopia, and ocular tumors, and discuss how intraocular exosomes contribute to the pathogenesis and progression of multiple eye diseases.

scholarly journals C-reactive protein isoforms differentially affect outer blood-retinal barrier integrity and function

2017 ◽  
Vol 312 (3) ◽  
pp. C244-C253 ◽  
Author(s):  
Blanca Molins ◽  
Anna Pascual ◽  
Méndez ◽  
Victor Llorenç ◽  
Javier Zarranz-Ventura ◽  
...  
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Protein Isoforms ◽  
Age Related Macular Degeneration ◽  
C Reactive Protein ◽  
Barrier Dysfunction ◽  
Blood Retinal Barrier ◽  
Reactive Protein ◽  
Anti Vegf ◽  
Age Related

The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier (oBRB) and is the prime target of early age-related macular degeneration (AMD). C-reactive protein (CRP), a serum biomarker for chronic inflammation and AMD, presents two different isoforms, monomeric (mCRP) and pentameric (pCRP), that may have a different effect on inflammation and barrier function in the RPE. The results reported in this study suggest that mCRP but not pCRP impairs RPE functionality by increasing paracellular permeability and disrupting the tight junction proteins ZO-1 and occludin in RPE cells. Additionally, we evaluated the effect of drugs commonly used in clinical settings on mCRP-induced barrier dysfunction. We found that a corticosteroid (methylprednisolone) and an anti-VEGF agent (bevacizumab) prevented mCRP-induced ARPE-19 barrier disruption and IL-8 production. Furthermore, bevacizumab was also able to revert mCRP-induced IL-8 increase after mCRP stimulation. In conclusion, the presence of mCRP within retinal tissue may lead to disruption of the oBRB, an effect that may be modified in the presence of corticosteroids or anti-VEGF drugs.

scholarly journals Oxidative stress-mediated TXNIP loss causes RPE dysfunction

2019 ◽  
Vol 51 (10) ◽  
pp. 1-13 ◽  
Author(s):  
Min Ji Cho ◽  
Sung-Jin Yoon ◽  
Wooil Kim ◽  
Jongjin Park ◽  
Jangwook Lee ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Function ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Common Factor ◽  
Age Related Macular Degeneration ◽  
Autophagic Flux ◽  
Blood Retinal Barrier ◽  
Rpe Cells ◽  
Age Related

Abstract The disruption of the retinal pigment epithelium (RPE), for example, through oxidative damage, is a common factor underlying age-related macular degeneration (AMD). Aberrant autophagy also contributes to AMD pathology, as autophagy maintains RPE homeostasis to ensure blood–retinal barrier (BRB) integrity and protect photoreceptors. Thioredoxin-interacting protein (TXNIP) promotes cellular oxidative stress by inhibiting thioredoxin reducing capacity and is in turn inversely regulated by reactive oxygen species levels; however, its role in oxidative stress-induced RPE cell dysfunction and the mechanistic link between TXNIP and autophagy are largely unknown. Here, we observed that TXNIP expression was rapidly downregulated in RPE cells under oxidative stress and that RPE cell proliferation was decreased. TXNIP knockdown demonstrated that the suppression of proliferation resulted from TXNIP depletion-induced autophagic flux, causing increased p53 activation via nuclear localization, which in turn enhanced AMPK phosphorylation and activation. Moreover, TXNIP downregulation further negatively impacted BRB integrity by disrupting RPE cell tight junctions and enhancing cell motility by phosphorylating, and thereby activating, Src kinase. Finally, we also revealed that TXNIP knockdown upregulated HIF-1α, leading to the enhanced secretion of VEGF from RPE cells and the stimulation of angiogenesis in cocultured human retinal microvascular endothelial cells. This suggests that the exposure of RPE cells to sustained oxidative stress may promote choroidal neovascularization, another AMD pathology. Together, these findings reveal three distinct mechanisms by which TXNIP downregulation disrupts RPE cell function and thereby exacerbates AMD pathogenesis. Accordingly, reinforcing or restoring BRB integrity by targeting TXNIP may serve as an effective therapeutic strategy for preventing or attenuating photoreceptor damage in AMD.

The Blood–Retinal Barrier in Retinal Disease

2009 ◽  
Vol 03 (02) ◽  
pp. 105 ◽  
Author(s):  
José Cunha-Vaz ◽  
Keyword(s):  
Diabetic Retinopathy ◽  
Tight Junctions ◽  
Retinal Pigment ◽  
Water Flux ◽  
Retinal Disease ◽  
Retinal Pigment Epithelial Cells ◽  
Age Related Macular Degeneration ◽  
Retinal Diseases ◽  
Blood Retinal Barrier ◽  
Age Related

The blood–ocular barrier system is formed by two main barriers: the blood–aqueous barrier and the blood–retinal barrier (BRB). The BRB is particularly tight and restrictive and is a physiological barrier that regulates ion, protein and water flux into and out of the retina. The BRB consists of inner and outer components, the inner BRB being formed of tight junctions between retinal capillary endothelial cells and the outer BRB of tight junctions between retinal pigment epithelial cells. The BRB is essential to maintaining the eye as a privileged site and is essential for normal visual function. Alterations of the BRB play a crucial role in the development of retinal diseases. The two most frequent and relevant retinal diseases, diabetic retinopathy and age-related macular degeneration (AMD), are directly associated with alterations of the BRB. Diabetic retinopathy is initiated by an alteration of the inner BRB and neovascular AMD is a result of an alteration of the outer BRB. Treatment of retinal diseases must also deal with the BRB either by using its specific transport mechanisms or by circumventing it through intravitreal injections

scholarly journals Nitrosative Stress in Retinal Pathologies: Review

Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 543 ◽  
Author(s):  
Antolin Cantó ◽  
Teresa Olivar ◽  
Francisco Javier Romero ◽  
María Miranda
Keyword(s):  
Lipid Membranes ◽  
Nitrosative Stress ◽  
Age Related Macular Degeneration ◽  
Retinal Blood Flow ◽  
Vascular Endothelial ◽  
Nitrogen Species ◽  
Cellular Functions ◽  
Age Related ◽  
Retinal Pathologies

Nitric oxide (NO) is a gas molecule with diverse physiological and cellular functions. In the eye, NO is used to maintain normal visual function as it is involved in photoreceptor light transduction. In addition, NO acts as a rapid vascular endothelial relaxant, is involved in the control of retinal blood flow under basal conditions and mediates the vasodilator responses of different substances such as acetylcholine, bradykinin, histamine, substance P or insulin. However, the retina is rich in polyunsaturated lipid membranes and is sensitive to the action of reactive oxygen and nitrogen species. Products generated from NO (i.e., dinitrogen trioxide (N2O3) and peroxynitrite) have great oxidative damaging effects. Oxygen and nitrogen species can react with biomolecules (lipids, proteins and DNA), potentially leading to cell death, and this is particularly important in the retina. This review focuses on the role of NO in several ocular diseases, including diabetic retinopathy, retinitis pigmentosa, glaucoma or age-related macular degeneration (AMD).

Phytotherapeutic and Natural Compound Applications for Age-Related, Inflammatory and Serious Eye Ailments

2020 ◽  
Vol 13 ◽  
Author(s):  
Methiye Mancak Karakuş ◽  
Ufuk Koca Çalışkan
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Properties ◽  
Natural Compounds ◽  
Eye Diseases ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Eye Problems ◽  
Surgical Treatments ◽  
Retinal Pathologies ◽  
First Time

Background: Tissue cells of the eye are sensitive to oxidative stress leading to oxidative damage and inflammation, which have crucial roles in the pathogenesis of most of the eye diseases. Moreover, factors such as age, angiogenesis, ischemia, genetic predisposition, diabetes, obesity, and smoking affect the onset and progression of ocular anomalies. Major eye diseases are either age-related such as Age-related macular degeneration, cataracts, diabetic retinopathy, glaucoma, dry eye, or inflammatory eye diseases such as blepharitis, conjunctivitis, uveitis and other retinal pathologies, which can cause ocular damage and visual problems through oxidative stress, inflammation pathways. Although there are conventional chemical or surgical treatments, due to their mainly antiapoptotic, anti-inflammatory and antioxidant properties, phytotherapeutic preparations and their natural compounds can be applied to prevent or treat eye disease as follows: oral, topical or both. Thus, this study aims to comprehensively evaluate the pre-clinical and clinical studies of the phytotherapeutics and natural compounds used in the prevention and treatment of common serious and painful eye diseases. Moreover, for the first time, nature-derived preparations/supplements commonly used for eye problems also included in this review to present applications of the extracts/compounds in the pharmaceutical field.

Protecting the aging eye with hydrogen sulfide

2020 ◽  
Author(s):  
Akash K George ◽  
Rubens Petit Homme ◽  
Dragana Stanisic ◽  
Suresh C. Tyagi ◽  
Mahavir Singh
Keyword(s):  
Hydrogen Sulfide ◽  
Ganglion Cells ◽  
Redox Homeostasis ◽  
Age Related Macular Degeneration ◽  
Glutamate Excitotoxicity ◽  
Blood Retinal Barrier ◽  
Functional Changes ◽  
Age Related ◽  
Oxygen Gradients ◽  
Vascular Occlusive Disease

Research demonstrates that senescence is associated with tissue and organ dysfunction, and the eye is no exception. Sequelae arising from aging have been well-defined as distinct clinical entities and vision-impairment has significant psychosocial consequences. Retina and adjacent tissues like retinal pigmented epithelium (RPE) and choroid are the key structures that are required for visual perception. Any structural and functional changes in retinal layers and blood retinal barrier (BRB) could lead to age-related macular degeneration (AMD), diabetic retinopathy (DR), and glaucoma. Further, there are significant oxygen gradients in eye that can lead to excessive reactive oxygen species (ROS) resulting in endoplasmic reticulum (ER) and mitochondrial stress response. These radicals are source of functional and morphological impairment in RPE, and retinal ganglion cells (RGCs). Therefore, ocular diseases could be summarized as disturbance in the redox homeostasis. Hyperhomocysteinemia (HHcy) is a risk factor and causes vascular occlusive disease of the retina. Interestingly, hydrogen sulfide (H2S) has been proven to be an effective antioxidant agent, and it can help treat diseases by alleviating stress and inflammation. Concurrent glutamate excitotoxicity, ER stress, and microglia activation are also linked to stress, thus H2S may offer additional interventional strategy. A refined understanding of the aging eye along with H2S biology, and pharmacology may help guide newer therapies for the eye

Sign in / Sign up

Export Citation Format

Share Document