scholarly journals Neurodegeneration, Neuroprotection and Regeneration in the Zebrafish Retina

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 633
Author(s):  
Salvatore L. Stella ◽  
Jasmine S. Geathers ◽  
Sarah R. Weber ◽  
Michael A. Grillo ◽  
Alistair J. Barber ◽  
...  

Neurodegenerative retinal diseases, such as glaucoma and diabetic retinopathy, involve a gradual loss of neurons in the retina as the disease progresses. Central nervous system neurons are not able to regenerate in mammals, therefore, an often sought after course of treatment for neuronal loss follows a neuroprotective or regenerative strategy. Neuroprotection is the process of preserving the structure and function of the neurons that have survived a harmful insult; while regenerative approaches aim to replace or rewire the neurons and synaptic connections that were lost, or induce regrowth of damaged axons or dendrites. In order to test the neuroprotective effectiveness or the regenerative capacity of a particular agent, a robust experimental model of retinal neuronal damage is essential. Zebrafish are being used more often in this type of study because their eye structure and development is well-conserved between zebrafish and mammals. Zebrafish are robust genetic tools and are relatively inexpensive to maintain. The large array of functional and behavioral tests available in zebrafish makes them an attractive model for neuroprotection studies. Some common insults used to model retinal disease and study neuroprotection in zebrafish include intense light, chemical toxicity and mechanical damage. This review covers the existing retinal neuroprotection and regeneration literature in the zebrafish and highlights their potential for future studies.

2021 ◽  
Vol 11 (5) ◽  
pp. 321
Author(s):  
Kyoung Min Kim ◽  
Tae-Young Heo ◽  
Aesul Kim ◽  
Joohee Kim ◽  
Kyu Jin Han ◽  
...  

Artificial intelligence (AI)-based diagnostic tools have been accepted in ophthalmology. The use of retinal images, such as fundus photographs, is a promising approach for the development of AI-based diagnostic platforms. Retinal pathologies usually occur in a broad spectrum of eye diseases, including neovascular or dry age-related macular degeneration, epiretinal membrane, rhegmatogenous retinal detachment, retinitis pigmentosa, macular hole, retinal vein occlusions, and diabetic retinopathy. Here, we report a fundus image-based AI model for differential diagnosis of retinal diseases. We classified retinal images with three convolutional neural network models: ResNet50, VGG19, and Inception v3. Furthermore, the performance of several dense (fully connected) layers was compared. The prediction accuracy for diagnosis of nine classes of eight retinal diseases and normal control was 87.42% in the ResNet50 model, which added a dense layer with 128 nodes. Furthermore, our AI tool augments ophthalmologist’s performance in the diagnosis of retinal disease. These results suggested that the fundus image-based AI tool is applicable for the medical diagnosis process of retinal diseases.


ASN NEURO ◽  
2021 ◽  
Vol 13 ◽  
pp. 175909142110097
Author(s):  
Kui Cui ◽  
Fan Yang ◽  
Turan Tufan ◽  
Muhammad U. Raza ◽  
Yanqiang Zhan ◽  
...  

Dysfunction of the central noradrenergic and dopaminergic systems is the primary neurobiological characteristic of Parkinson’s disease (PD). Importantly, neuronal loss in the locus coeruleus (LC) that occurs in early stages of PD may accelerate progressive loss of dopaminergic neurons. Therefore, restoring the activity and function of the deficient noradrenergic system may be an important therapeutic strategy for early PD. In the present study, the lentiviral constructions of transcription factors Phox2a/2b, Hand2 and Gata3, either alone or in combination, were microinjected into the LC region of the PD model VMAT2 Lo mice at 12 and 18 month age. Biochemical analysis showed that microinjection of lentiviral expression cassettes into the LC significantly increased mRNA levels of Phox2a, and Phox2b, which were accompanied by parallel increases of mRNA and proteins of dopamine β-hydroxylase (DBH) and tyrosine hydroxylase (TH) in the LC. Furthermore, there was considerable enhancement of DBH protein levels in the frontal cortex and hippocampus, as well as enhanced TH protein levels in the striatum and substantia nigra. Moreover, these manipulations profoundly increased norepinephrine and dopamine concentrations in the striatum, which was followed by a remarkable improvement of the spatial memory and locomotor behavior. These results reveal that over-expression of these transcription factors in the LC improves noradrenergic and dopaminergic activities and functions in this rodent model of PD. It provides the necessary groundwork for the development of gene therapies of PD, and expands our understanding of the link between the LC-norepinephrine and dopamine systems during the progression of PD.


2019 ◽  
Vol 30 (8) ◽  
pp. 839-855 ◽  
Author(s):  
Mahasweta Das ◽  
Karthick Mayilsamy ◽  
Shyam S. Mohapatra ◽  
Subhra Mohapatra

Abstract Traumatic brain injury (TBI) is a major cause of injury-related mortality and morbidity in the USA and around the world. The survivors may suffer from cognitive and memory deficits, vision and hearing loss, movement disorders, and different psychological problems. The primary insult causes neuronal damage and activates astrocytes and microglia which evokes immune responses causing further damage to the brain. Clinical trials of drugs to recover the neuronal loss are not very successful. Regenerative approaches for TBI using mesenchymal stem cells (MSCs) seem promising. Results of preclinical research have shown that transplantation of MSCs reduced secondary neurodegeneration and neuroinflammation, promoted neurogenesis and angiogenesis, and improved functional outcome in the experimental animals. The functional improvement is not necessarily related to cell engraftment; rather, immunomodulation by molecular factors secreted by MSCs is responsible for the beneficial effects of this therapy. However, MSC therapy has a few drawbacks including tumor formation, which can be avoided by the use of MSC-derived exosomes. This review has focused on the research works published in the field of regenerative therapy using MSCs after TBI and its future direction.


Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 557 ◽  
Author(s):  
Siebren Faber ◽  
Ronald Roepman

The light sensing outer segments of photoreceptors (PRs) are renewed every ten days due to their high photoactivity, especially of the cones during daytime vision. This demands a tremendous amount of energy, as well as a high turnover of their main biosynthetic compounds, membranes, and proteins. Therefore, a refined proteostasis network (PN), regulating the protein balance, is crucial for PR viability. In many inherited retinal diseases (IRDs) this balance is disrupted leading to protein accumulation in the inner segment and eventually the death of PRs. Various studies have been focusing on therapeutically targeting the different branches of the PR PN to restore the protein balance and ultimately to treat inherited blindness. This review first describes the different branches of the PN in detail. Subsequently, insights are provided on how therapeutic compounds directed against the different PN branches might slow down or even arrest the appalling, progressive blinding conditions. These insights are supported by findings of PN modulators in other research disciplines.


Planta Medica ◽  
2019 ◽  
Vol 85 (17) ◽  
pp. 1292-1303 ◽  
Author(s):  
Isabel Martínez-Solís ◽  
Nuria Acero ◽  
Francisco Bosch-Morell ◽  
Encarna Castillo ◽  
María Eugenia González-Rosende ◽  
...  

AbstractLike other tissues of the central nervous system, the retina is susceptible to damage by oxidative processes that result in several neurodegenerative disease such as age-related macular degeneration, diabetic retinopathy, glaucoma, ischaemic retinal disease, retinal disease produced by light oxidation, and detached retina, among other diseases. The use of antioxidant substances is a solution to some health problems caused by oxidative stress, because they regulate redox homeostasis and reduce oxidative stress. This is important for neurodegeneration linked to oxidation processes. In line with this, Ginkgo biloba is a medicinal plant with excellent antioxidant properties whose effects have been demonstrated in several degenerative processes, including retinal diseases associated with neurodegeneration. This review describes the current literature on the role of ginkgo in retinal diseases associated with neurodegeneration. The information leads to the conclusion that G. biloba extracts might be a good option to improve certain neurodegenerative retinal diseases, but more research is needed to determine the safety and efficacy of G. biloba in these retinal degenerative processes.


2019 ◽  
Vol 45 (10) ◽  
pp. 668-672
Author(s):  
Landon James Rohowetz

Anti-vascular endothelial growth factor (anti-VEGF) therapy has revolutionised the treatment of a variety of ophthalmic conditions and has become the first-line therapy for a range of retinal diseases. Bevacizumab, a VEGF inhibitor first approved for the treatment of colorectal cancer, has been shown to be nearly or virtually as effective and safe as other anti-VEGF therapies in the treatment of certain retinal diseases but is not approved or registered by the Food and Drug Administration or European Medicines Agency. While other anti-VEGF options are approved and registered, they are generally more expensive and less accessible. Accordingly, despite its off-label status, bevacizumab is frequently used for a variety of disabling retinal diseases. Indeed, bevacizumab is included on the World Health Organization’s list of essential medicines. However, its use in some parts of the world remains restricted due to its off-label status. How, then, should healthcare authorities approach this situation? What are the ethical and societal implications of adhering to a standard and generally effective evaluation and approval system while restricting access to a potentially cost-saving therapy? In countries where its use is not restricted, how should providers approach off-label treatment with bevacizumab? By examining the evidence behind bevacizumab’s efficacy and safety and evaluating the individual and societal implications of off-label use and restriction, this paper illustrates the ethical factors providers and policy makers must consider in the off-label use of bevacizumab and ultimately argues for increased access to bevacizumab in the treatment of retinal disease.


1995 ◽  
Vol 7 (3) ◽  
pp. 647 ◽  
Author(s):  
EC Mallard ◽  
CE Williams ◽  
BM Johnston ◽  
PD Gluckman

Perinatal asphyxia is thought to be a significant cause of still birth and neurological sequelae. Although several different patterns of neuronal injury are seen in the newborn, previously little was known about the precise cause and effect relationships. This brief review summarizes recent research which has identified how prenatal factors such as recurrent episodes of asphyxia, gestational age, growth retardation and cerebral temperature may influence the severity and regional distribution of neuronal loss.


Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2594
Author(s):  
Yue Ruan ◽  
Tobias Böhmer ◽  
Subao Jiang ◽  
Adrian Gericke

The retina is a part of the central nervous system, a thin multilayer with neuronal lamination, responsible for detecting, preprocessing, and sending visual information to the brain. Many retinal diseases are characterized by hemodynamic perturbations and neurodegeneration leading to vision loss and reduced quality of life. Since catecholamines and respective bindings sites have been characterized in the retina, we systematically reviewed the literature with regard to retinal expression, distribution and function of alpha1 (α1)-, alpha2 (α2)-, and beta (β)-adrenoceptors (ARs). Moreover, we discuss the role of the individual adrenoceptors as targets for the treatment of retinal diseases.


Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 705 ◽  
Author(s):  
Emilie Picard ◽  
Alejandra Daruich ◽  
Jenny Youale ◽  
Yves Courtois ◽  
Francine Behar-Cohen

Iron is essential for cell survival and function. It is a transition metal, that could change its oxidation state from Fe2+ to Fe3+ involving an electron transfer, the key of vital functions but also organ dysfunctions. The goal of this review is to illustrate the primordial role of iron and local iron homeostasis in retinal physiology and vision, as well as the pathological consequences of iron excess in animal models of retinal degeneration and in human retinal diseases. We summarize evidence of the potential therapeutic effect of iron chelation in retinal diseases and especially the interest of transferrin, a ubiquitous endogenous iron-binding protein, having the ability to treat or delay degenerative retinal diseases.


2020 ◽  
Vol 13 (11) ◽  
pp. 379
Author(s):  
Michał Wiciński ◽  
Eryk Wódkiewicz ◽  
Karol Górski ◽  
Maciej Walczak ◽  
Bartosz Malinowski

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are oral anti-hyperglycemic agents approved for the treatment of type 2 diabetes mellitus. Some reports suggest their presence in the central nervous system and possible neuroprotective properties. SGLT2 inhibition by empagliflozin has shown to reduce amyloid burden in cortical regions of APP/PS1xd/db mice. The same effect was noticed regarding tau pathology and brain atrophy volume. Empagliflozin presented beneficial effect on cognitive function, which may be connected to an increase in cerebral brain-derived neurotrophic factor. Canagliflozin and dapagliflozin may possess acetylcholinesterase inhibiting activity, resembling in this matter Alzheimer’s disease-registered therapies. SGLT2 inhibitors may prove to impact risk factors of atherosclerosis and pathways participating both in acute and late stage of stroke. Their mechanism of action can be related to induction in hepatocyte nuclear factor-1α, vascular endothelial growth factor-A, and proinflammatory factors limitation. Empagliflozin may have a positive effect on preservation of neurovascular unit in diabetic mice, preventing its aberrant remodeling. Canagliflozin seems to present some cytostatic properties by limiting both human and mice endothelial cells proliferation. The paper presents potential mechanisms of SGLT-2 inhibitors in conditions connected with neuronal damage, with special emphasis on Alzheimer’s disease and cerebral ischemia.


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