Neurodegenerative Eye Disease Research Articles

WNT-inhibitory factor 1-mediated glycolysis protects photoreceptor cells in diabetic retinopathy

BackgroundIn diabetic retinopathy (DR), hypoxia-inducible factor (HIF-1α) induces oxidative stress by upregulating glycolysis. This process leads to neurodegeneration, particularly photoreceptor cell damage, which further contributes to retinal microvascular deterioration. Further, the regulation of Wnt-inhibitory factor 1 (WIF1), a secreted Wnt signaling antagonist, has not been fully characterized in neurodegenerative eye diseases. We aimed to explore the impact of WIF1 on photoreceptor function within the context of DR.MethodTwelve-week-old C57BL/KsJ-db/db mice were intravitreally injected with WIF1 overexpression lentivirus. After 4 weeks, optical coherence tomography (OCT), transmission electron microscopy (TEM), H&E staining, and electroretinography (ERG) were used to assess the retinal tissue and function. The potential mechanism of action of WIF1 in photoreceptor cells was explored using single-cell RNA sequencing. Under high-glucose conditions, 661 W cells were used as an in vitro DR model. WIF1-mediated signaling pathway components were assessed using quantitative real-time PCR, immunostaining, and western blotting.ResultTypical diabetic manifestations were observed in db/db mice. Notably, the expression of WIF1 was decreased at the mRNA and protein levels. These pathological manifestations and visual function improved after WIF1 overexpression in db/db mice. TEM demonstrated that WIF1 restored damaged mitochondria, the Golgi apparatus, and photoreceptor outer segments. Moreover, ERG indicated the recovery of a-wave potential amplitude. Single-cell RNA sequencing and in vitro experiments suggested that WIF1 overexpression prevented the expression of glycolytic enzymes and lactate production by inhibiting the canonical Wnt signaling pathway, HIF-1α, and Glut1, thereby reducing retinal and cellular reactive oxygen species levels and maintaining 661 W cell viability.ConclusionsWIF1 exerts an inhibitory effect on the Wnt/β-catenin-HIF-1α-Glut1 glycolytic pathway, thereby alleviating oxidative stress levels and mitigating pathological structural characteristics in retinal photoreceptor cells. This mechanism helps preserve the function of photoreceptor cells in DR and indicates that WIF1 holds promise as a potential therapeutic candidate for DR and other neurodegenerative ocular disorders.Graphical

Small extracellular vesicles derived from human induced pluripotent stem cell-differentiated neural progenitor cells mitigate retinal ganglion cell degeneration in a mouse model of optic nerve injury.

JOURNAL/nrgr/04.03/01300535-202502000-00034/figure1/v/2024-05-28T214302Z/r/image-tiff Several studies have found that transplantation of neural progenitor cells (NPCs) promotes the survival of injured neurons. However, a poor integration rate and high risk of tumorigenicity after cell transplantation limits their clinical application. Small extracellular vesicles (sEVs) contain bioactive molecules for neuronal protection and regeneration. Previous studies have shown that stem/progenitor cell-derived sEVs can promote neuronal survival and recovery of neurological function in neurodegenerative eye diseases and other eye diseases. In this study, we intravitreally transplanted sEVs derived from human induced pluripotent stem cells (hiPSCs) and hiPSCs-differentiated NPCs (hiPSC-NPC) in a mouse model of optic nerve crush. Our results show that these intravitreally injected sEVs were ingested by retinal cells, especially those localized in the ganglion cell layer. Treatment with hiPSC-NPC-derived sEVs mitigated optic nerve crush-induced retinal ganglion cell degeneration, and regulated the retinal microenvironment by inhibiting excessive activation of microglia. Component analysis further revealed that hiPSC-NPC derived sEVs transported neuroprotective and anti-inflammatory miRNA cargos to target cells, which had protective effects on RGCs after optic nerve injury. These findings suggest that sEVs derived from hiPSC-NPC are a promising cell-free therapeutic strategy for optic neuropathy.

An efficient novel approach for glaucoma classification on retinal fundus images through machine learning paradigm

Glaucoma, a neuro-degenerative eye disease, is the result of an increase in intraocular pressure inside the retina. It is the second-leading cause of blindness worldwide, and if an early diagnosis is not made, it can lead to total blindness. There is a critical need to develop a system that can work well without a lot of equipment, qualified medical professionals, and requires less time about this core issue. This article provides a thorough examination of the main machine learning (ML) techniques employed in the processing of retinal images for the identification and diagnosis of glaucoma. Machine learning (ML) has been demonstrated to be a crucial technique for the development of computer-assisted technology. Machine learning (ML) techniques can be used to construct predictive models for the early diagnosis of glaucoma. Our objective is to develop a machine learning algorithm that can accurately forecast the likelihood of developing glaucoma using patient data. Ophthalmologists have also conducted a significant amount of secondary research over the years. Such characteristics emphasise the importance of ML while analysing retinal pictures.

Analysis of microRNA expression in rat retina at the early stages of retinopathy development

Age-related macular degeneration (AMD), a neurodegenerative eye disease, is the primary cause of blindness globally, especially affecting the elderly population. MicroRNAs, a type of single-stranded, non-coding RNAs of about 22 nucleotides in length, primarily regulate gene expression negatively. Alterations in the miRNA profile during AMD’s development could potentially aid in early detection and progression monitoring of the disease. However, no data are available on the microRNA expression patterns in the retina during the early stages of AMD. Investigating the molecular mechanisms that underlie age-related retinal degeneration at an early stage, prior to the manifestation of any symptoms, could provide insights into the molecular events that initiate the irreversible stage. In the case of OXYS rats with accelerated aging, dystrophic changes in the RPE, neuroretinal thinning, and impaired choroidal microcirculation — the primary indicators of the dry form of AMD — spontaneously occur by the age of 3 months [1]. A comparative analysis was conducted in this study on microRNA expression in the retinas of OXYS rats at two different stages of retinopathy — 20 days (preclinical) and 3 months (manifestation) — as well as in control Wistar rats. Small RNA-seq sequencing was performed on the DNBSEQ platform. According to differential expression analysis (DESeq2, q-value 0.05), at 20 days of age, 2 microRNAs exhibited altered expression in OXYS rats compared to Wistar rats. Similarly, at 3 months of age, the expression of 16 microRNAs in OXYS rats was altered compared to Wistars, with 7 miRNAs showing increased levels and 9 miRNAs showing decreased levels. Analysis of age-related changes in miRNA expression demonstrated that in the OXYS rat retina between 20 days and 3 months, the levels of 134 miRNAs altered: 59 miRNAs increased, and 75 miRNAs decreased. Over the course of 20 days to 3 months, 94 miRNAs underwent alterations in the retinas of Wistar rats. Among these, the level of 48 miRNAs increased while the level of 46 miRNAs decreased. The RNAhybrid, miRanda, and TargetScan programs were used to search for target genes of differentially presented miRNAs among different groups. Following this, gene ontologies were studied. In comparison to Wistar rats, “adhesion contacts” and “synaptic vesicle cycle” categories are noticeably populated with target genes of miRNA DE at 20 days in OXYS rats. MiRNA target genes with lower levels at 3 months in OXYS rats compared to Wistar rats are significantly enriched in categories such as vascular branching, extracellular matrix organization, adhesion, and protein deubiquitination. Target genes with increased miRNA levels at 3 months in OXYS rats, compared to Wistar rats, are significantly represented in various signaling pathways, such as mTOR, MAPK, VEGF, and thyroid hormone. Target genes, which serve as common targets for at least 10 microRNAs (miRNAs), were chosen for analysis of the targetome subject to regulation by miRNA molecules exhibiting modified expression. Targetomes containing 400 to 600 genes were obtained for miRNAs that increased or decreased levels in both OXYS and Wistar rats between 20 days and 3 months. Notably, these targetomes were enriched in categories such as axonogenesis, retinal layer formation, visual learning, focal adhesion, and endocytosis. Profiling of 84 miRNAs of the retina of OXYS and Wistar rats at the age of 20 days and 3 months was carried out using PCR panels (Qiagen) to verify the results of small RNA-seq. Our analysis revealed highly convergent results between sequencing and PCR panels. Thus, 16 miRNAs showing altered expression in OXYS retina may serve as potential biomarkers and new targets for studying AMD pathogenesis.

Role of NLRP3 in the immunopathogenesis of neurodegenerative eye diseases

Neurodegenerative eye pathology is one of the leading causes of visual impairment and blindness worldwide. Primary open-angle glaucoma (POAG) belongs to the group of neurodegenerative ophthalmic diseases and is characterized by a permanent or periodic increase in intraocular pressure, followed by development of typical visual field defects, decreased visual acuity and optic nerve atrophy. Recent studies show that local inflammation, triggered by the innate immune system is the first line of defense against the pathogens and tissue destruction products, playing an important role in the POAG pathogenesis. The aim was to study the neurodegenerative ophthalmic disorder in a rabbit model, and to compare the data on distribution of alleles and genotypes of the polymorphic marker rs7525979 of NLRP3 gene in the patients with POAG. At the first stage, we studied the complex tissue samples of the retina/retinal pigment epithelium (TCS/RPE) isolated from the eyes of 14 experimental animals and 7 intact rabbits without eye damage. Neurodegenerative pathology of the eye in rabbits was carried out in the Experimental Center at the Helmholtz National Medical Research Center by a single subretinal injection of 0.01 ml of 0.9% sodium chloride solution. NLRP3 gene expression levels in TCS/RPE samples were evaluated by real-time polymerase chain reaction (PCR-RV). At the second stage, peripheral blood samples were examined in patients who were diagnosed with POAG of various stages, as well as without glaucoma. DNA was isolated from blood samples, which was subsequently analyzed for the polymorphic markers study using PCR-RT technique. According to the results of the study, we noted an increased expression of the NLRP3 gene in the TCS/RPE samples from experimental animals with simulated retinal degeneration. Moreover, an association of alleles and genotypes of the NLRP3 gene was revealed in patients with POAG. The data obtained may be indicative for involvement of NLRP3 inflammasome components in development of neurodegenerative retinal lesions in POAG.

Neuroprotection of Retinal Ganglion Cells Suppresses Microglia Activation in a Mouse Model of Glaucoma.

Microglial activation has been implicated in many neurodegenerative eye diseases, but the interrelationship between cell loss and microglia activation remains unclear. In glaucoma, there is no consensus yet whether microglial activation precedes or is a consequence of retinal ganglion cell (RGC) degeneration. We therefore investigated the temporal and spatial appearance of activated microglia in retina and their correspondence to RGC degeneration in glaucoma. We used an established microbead occlusion model of glaucoma in mouse whereby intraocular pressure (IOP) was elevated. Specific antibodies were used to immunolabel microglia in resting and activated states. To block retinal gap junction (GJ) communication, which has been shown previously to provide significant neuroprotection of RGCs, the GJ blocker meclofenamic acid was administered or connexin36 (Cx36) GJ subunits were ablated genetically. We then studied microglial activation at different time points after microbead injection in control and neuroprotected retinas. Histochemical analysis of flatmount retinas revealed major changes in microglia morphology, density, and immunoreactivity in microbead-injected eyes. An early stage of microglial activation followed IOP elevation, as indicated by changes in morphology and cell density, but preceded RGC death. In contrast, the later stage of microglia activation, associated with upregulation of major histocompatibility complex class II expression, corresponded temporally to the initial loss of RGCs. However, we found that protection of RGCs afforded by GJ blockade or genetic ablation largely suppressed microglial changes at all stages of activation in glaucomatous retinas. Together, our data strongly suggest that microglia activation in glaucoma is a consequence, rather than a cause, of initial RGC degeneration and death.

Safety and Target Engagement of Complement C1q Inhibitor ANX007 in Neurodegenerative EyeDisease: Results from Phase I Studies in Glaucoma.

Complement C1q, the initiating molecule of the classical complement cascade, is involved in synapse elimination and neuronal loss in neurodegenerative diseases including glaucoma. Here we report an evaluation of the safety, tolerability, and ocular pharmacokinetics (PK) and pharmacodynamics of intravitreal (IVT) injections of ANX007, an anti-C1q monoclonal antibody fragment that blocks activation of the classical complement cascade. An open-label, single-dose-escalation phase Ia study followed by a double-masked, randomized, sham-controlled, repeat-injection phase Ib study. A total of 26 patients with primary open-angle glaucoma. Nine patients with primary open-angle glaucoma (mean Humphrey visual field deviation between-3 and-18 decibels [dB]) were enrolled in phase Ia and received single doses of ANX007 (1.0 mg, n=3; 2.5 mg, n=3; or 5.0 mg, n=3). Seventeen patients (mean Humphrey visual field deviation between-3 and-24 dB) were enrolled in phase Ib and randomized to 2 monthly doses of ANX007 (sham, n=6; 2.5 mg ANX007, n=6; or 5 mg ANX007, n=5). Safety and tolerability (including laboratory evaluation of urinalysis, complete blood count, and serum chemistries), ANX007 PK, target engagement, and immunogenicity. The mean age overall was 70 years in phase Ia and 68 years in phase Ib. In both studies, no serious adverse events were observed, no non-ocular treatment-emergent adverse events (TEAEs) attributable to study drug were reported, and ocular TEAEs were mild. Intraocular pressure returned to normal levels for all patients within 45 minutes of IVT injection. No clinically significant deviations in laboratory results were observed. In the phase Ib study, C1q in the aqueous humor was reduced to undetectable levels in both the 2.5 mg and 5 mg cohorts 4 weeks after the first ANX007 dose. In these studies, single and repeat IVT ANX007 injections were well tolerated and demonstrated full target engagement 4 weeks after dosing with both low and high doses, supporting monthly or less-frequent dosing. Further investigation in neurodegenerative ocular diseases is warranted. Proprietary or commercial disclosure may be found after the references.

Investigation of local expression of NLRP3 inflammasome complex genes in modeling retinal degeneration <i>in vivo</i>

Neurodegenerative ophthalmopathology is one of the main causes of irreversible blindness and disability in the world. In the pathogenesis of diseases of this group, more and more attention has recently been paid to the role of local inflammation caused by the activation of innate immunity and the mechanisms of its genetic regulation. In recent years, works have appeared in the field of experimental ophthalmology that have demonstrated the possibility of NLRP1, NLRP3 inflammasome complexes assembling when exposed to hyperglycemia, oxygen deprivation of retinal cells, as well as modeling compressive stress similar to that in glaucoma [15]. However, the mechanism of inflammasome involvement in the development of neurodegenerative eye diseases remains unclear. The aim of the study was to investigate the local expression of genes encoding proteins of the NLRP3 inflammasome complex (NLRP3, CASP-1) in an experimental model of retinal degeneration in rabbits. The studies were performed on samples of tissue complex (TC) of the retina/retinal pigment epithelium (RPE) (retina/RPE TC), isolated from the eyes of 14 New Zealand albino rabbits, in which degenerative retinal lesion was modeled by a single subretinal injection of 0.01 mL of 0.9% sodium chloride solution, and 7 healthy rabbits without eye damage. The formation of retinal degeneration was judged on the basis of changes in morphofunctional parameters obtained during specialized ophthalmological research methods (optical coherence tomography, fundus autofluorescence, electroretinography) at follow-up periods of 1, 3 and 6 months. The level of expression of NLRP3 and CASP-1 genes in the retina/RPE TC was evaluated by reverse transcription polymerase chain reaction (RT-PCR). According to the results of the study, a statistically significant increase in NLRP3 gene expression (p < 0.001) was noted in the retina/RPE TC of experimental animals, which may indicate the involvement of NLRP-3 inflammasome components in the development of neurodegenerative retinal lesions. At the same time, the expression of the gene encoding CASP-1 was detected only in the retina/RPE TC of experimental eyes and is probably due to local inflammatory mechanisms in the retinal tissue. The high level of NLRP3, CASP-1 mRNA, detected in all retina/RPE TC samples of experimental eyes at late stages of the experiment (3 and 6 months), allows us to assume the formation of mechanisms (for example, activated glial phenotype) that support inflammation in retinal tissue. This should be taken into account in actively developing transplantation methods for the treatment of retinal degeneration.

Paeoniflorin Protects Retinal Ganglion Cells in Experimental Glaucoma

Glaucoma is a progressive neurodegenerative eye disease characterized by raised intraocular pressure and a loss of retinal ganglion cells, resulting in partial or total vision loss. We have investigated whether paeoniflorin could reduce intraocular pressure and improve retinal ganglion cell survival in glaucoma-induced rats. In rats with raised intraocular pressure induced by injecting hypertonic saline solution into the limbal veins, oral paeoniflorin markedly brought down the elevated intraocular pressure and significantly prevented retinal ganglion cell loss, as determined by the terminal deoxynucleotidyl transferase dUTP nick end labeling assay and Fluoro-Gold labeling. The expression of the transforming growth factor β protein was effectively diminished by paeoniflorin administration. Also, the expression of extracellular matrix components matrix metalloproteinase 9 a tissue inhibitor of metalloproteinase 1—laminin, collagen I, and collagen IV in the optic nerve head and retinal ganglion cell layer were effectively diminished. Paeoniflorin substantially upregulated the activation of Janus kinase-2/signal transducer and activator of transcription proteins-3 signaling, which plays a crucial role in retinal ganglion cell survival. These results illustrate a protective effect of paeoniflorin through reduction of intraocular pressure, retinal ganglion cell loss, and changes in the extracellular matrix by regulating transforming growth factor β2 signaling and Janus kinase-2/signal transducer and activator of transcription protein-3 signaling. The present work demonstrates that paeoniflorin may be a promising therapeutic agent for glaucoma.

Development of melatonin-loaded, human-serum-albumin nanoparticles formulations using different methods of preparation for ophthalmic administration

The use of proteins such as human serum albumin (HSA) to form nanometric systems seems very promising since they are non-toxic, biodegradable and have no antigenic activity. This molecule is ideal to transport insoluble drugs such as melatonin (Mel), which has antiapoptotic and antioxidant properties and appears promising for the treatment of neurodegenerative eye diseases. The objective of this study was to obtain nanoparticulate systems loaded with Mel, improving the conventional desolvation method. Systems were stabilised using two different strategies: one through the use of Eudragit S100 as a cross-linking agent and the other through thermal stabilisation. The systems thus obtained (Np-HSA-Eu-Mel and Np-HSA-Mel, respectively) were characterised and compared in terms of physicochemical and pharmacotechnical parameters. Whitish colloidal dispersions of nanometric size (≈170 nm), spherical shape, and monodisperse population were obtained. Besides, the pH was close to neutrality reaching 20 % drug encapsulation whereas the process performance was higher than 80 %. In FT-IR studies, thermal analysis and X-ray diffraction (XRD), the incorporation of the drug in the cavities of the nanoparticles could be evidenced. Regarding the physical stability of nanoparticles, for Np-HSA-Eu-Mel instability was observed at pH > 7. However, Np-HSA-Mel was able to remain stable at different pH levels. Mel release from these systems was consequently affected, where the former released faster than the active compared to the last.On the other hand, it was observed that the drying process (lyophilization in this case) applied to the nanoparticles suspensions does not affect their original properties after redispersion over a three months period. Likewise, the formulation did not produce irritation when administered topically, whereas when administered subconjunctivally, only slight irritation was observed 24 h after administration. According to the result of this study, the Np-HSA-Mel formulation could achieve advantageous properties as a vehicle for the transport of insoluble drugs for the treatment of neurodegenerative diseases at the ocular level.

Specific changes of zinc and metallothioneins during the in vitro maturation and ageing of a retinal pigment epithelium cellular model

AbstractPurposeDuring ageing, the retinal pigment epithelium (RPE) undergoes several morphological and physiological alterations such as loss of melanin, formation of extracellular deposits and metal dyshomeostasis. We examined the age‐related changes in the transcriptome and metallome (metal content in cellular cytosol, membrane and culture media) of the ageing RPE to give an insight into the origin of risk factors linked with neurodegenerative eye diseases like AMD.MethodsWe established a primary human RPE cells culture model to study the maturation (10, 21 and 59 days in culture) and ageing (91 and 133 days in culture) of cells in vitro. We analyzed the transcriptome by RNA sequencing (RNAseq) and determined the metallome by inductively coupled plasma mass spectrometry (ICP‐MS). Localization of specific proteins was carried out by immunocytochemistry.ResultsRPE differentiation markers increased significantly from 10 to 59 days in culture, followed by a decrease from 91 days onwards, as determined by RNAseq and immunocytochemistry assays. After 59 days in culture, there was an alteration in the expression of genes associated with essential biological processes, some of them being phosphorylation, oxidation‐reduction and ion transport. Metal content (i.e., Na, P, Mg, Ca, Cu and Zn) in the cellular cytosol and membranes showed mixed tendencies with time. Interestingly, cytosolic zinc levels decreased from 10 to 59 days (maturing RPE) but increased at 91 and 133 days (ageing RPE). This biphasic change was mirrored by the gene expression changes of specific isoforms of the zinc‐binding metallothioneins including MT1G and MT2A.ConclusionsGene expression and metal content showed time‐dependent changes in the in vitro RPE cell culture model. We observed a specific association between zinc levels and metallothionein expressions during maturation and ageing that, if confirmed by further evidences, may shed light for the metal dyshomeostasis observed during AMD.

Новые возможности нейропротекторной терапии при дегенеративных и ишемических поражениях сетчатки и зрительного нерва

The presented literature review highlights the significance of the ischemia as a reason of reducing visual acuity in case of having such diseases as rhegmatogenous retinal detachment, primary open-angle glaucoma, AION and optic nerve atrophy. The expediency of prescribing “Cytoflavin” in the background of ischemia in case of neurodegenerative eye diseases is justified. The evidence of the effectiveness of this medicine in ophthalmological practice is provided.

Automated glaucoma detection from fundus images using wavelet-based denoising and machine learning

Glaucoma is a domineering and irretrievable neurodegenerative eye disease produced by the optical nerve head owed to extended intra-ocular stress inside the eye. Recognition of glaucoma is an essential job for ophthalmologists. In this paper, we propose a methodology to classify fundus images into normal and glaucoma categories. The proposed approach makes use of image denoising of digital fundus images by utilizing a non-Gaussian bivariate probability distribution function to model the statistics of wavelet coefficients of glaucoma images. The traditional image features were extracted followed by the popular feature selection algorithm. The selected features are then fed to the least square support vector machine classifier employing various kernel functions. The comparison result shows that the proposed approach offers maximum classification accuracy of nearly 91.22% over the existing best approaches.

The rare C9 P167S risk variant for age-related macular degeneration increases polymerization of the terminal component of the complement cascade.

Age-related macular degeneration (AMD) is a complex neurodegenerative eye disease with behavioral and genetic etiology and is the leading cause of irreversible vision loss among elderly Caucasians. Functionally significant genetic variants in the alternative pathway of complement have been strongly linked to disease. More recently, a rare variant in the terminal pathway of complement has been associated with increased risk, Complement component 9 (C9) P167S. To assess the functional consequence of this variant, C9 levels were measured in two independent cohorts of AMD patients. In both cohorts, it was demonstrated that the P167S variant was associated with low C9 plasma levels. Further analysis showed that patients with advanced AMD had elevated sC5b-9 compared to those with non-advanced AMD, although this was not associated with the P167S polymorphism. Electron microscopy of membrane attack complexes (MACs) generated using recombinantly produced wild type or P167S C9 demonstrated identical MAC ring structures. In functional assays, the P167S variant displayed a higher propensity to polymerize and a small increase in its ability to induce hemolysis of sheep erythrocytes when added to C9-depleted serum. The demonstration that this C9 P167S AMD risk polymorphism displays increased polymerization and functional activity provides a rationale for the gene therapy trials of sCD59 to inhibit the terminal pathway of complement in AMD that are underway.

Glaucoma detection in retinal fundus images using U-Net and supervised machine learning algorithms

Background and objectiveGlaucoma is a neuro-degenerative eye disease developed due to an increase in the Intra-ocular Pressure inside the retina. Being the second largest cause of blindness worldwide, it can lead the person towards complete blindness if an early diagnosis does not take place. With respect to this underlying issue, there is an immense need of developing a system that can effectively work in the absence of excessive equipments, skilled medical practitioners and also is less time consuming. MethodsThis work proposes an offline Computer-Aided Diagnosis (CAD) system for glaucoma diagnosis using retinal fundus images. This application is developed using image processing, deep learning and machine learning approaches. Le-Net architecture is used for input image validation and Region of Interest (ROI) detection is done using brightest spot algorithm. Further, the optic disc and optic cup segmentation is performed with the help of U-Net architecture and classification is done using SVM, Neural Network and Adaboost classifiers. ResultsThe accuracy of 99% is achieved using Le-Net for input image validation. Considering the application of brightest spot algorithm, an accuracy of 98.67% is achieved for ROI extraction. Further, a dice-coefficient of 0.93 and 0.87 was attained for the segmentation of optic disc and optic cup respectively using U-Net architecture. Using SVM, Neural Network and Adaboost classifiers, the proposed methodology managed to achieve a classification accuracy, recall, specificity and sensitivity of 100%, thus proving the system to be reliable and promising. ConclusionsIn conclusion, the proposed desktop application is easy to use and can play a major role in early glaucoma detection. The modular design of the CAD system is made up of a set of standalone components that can be used for a variety of different tasks for detecting and classifying glaucoma. Due to the model being trained on a variety of different datasets, the system proves to be robust and more accurate.

Biotechnology and Biomaterial-Based Therapeutic Strategies for Age-Related Macular Degeneration. Part II: Cell and Tissue Engineering Therapies.

Age-related Macular Degeneration (AMD) is an up-to-date untreatable chronic neurodegenerative eye disease of multifactorial origin, and the main causes of blindness in over 65 y.o. people. It is characterized by a slow progression and the presence of a multitude of factors, highlighting those related to diet, genetic heritage and environmental conditions, present throughout each of the stages of the illness. Current therapeutic approaches, mainly consisting on intraocular drug delivery, are only used for symptoms relief and/or to decelerate the progression of the disease. Furthermore, they are overly simplistic and ignore the complexity of the disease and the enormous differences in the symptomatology between patients. Due to the wide impact of the AMD and the up-to-date absence of clinical solutions, Due to the wide impact of the AMD and the up-to-date absence of clinical solutions, different treatment options have to be considered. Cell therapy is a very promising alternative to drug-based approaches for AMD treatment. Cells delivered to the affected tissue as a suspension have shown poor retention and low survival rate. A solution to these inconveniences has been the encapsulation of these cells on biomaterials, which contrive to their protection, gives them support, and favor their retention of the desired area. We offer a two-papers critical review of the available and under development AMD therapeutic approaches, from a biomaterials and biotechnological point of view. We highlight benefits and limitations and we forecast forthcoming alternatives based on novel biomaterials and biotechnology methods. In this second part we review the preclinical and clinical cell-replacement approaches aiming at the development of efficient AMD-therapies, the employed cell types, as well as the cell-encapsulation and cell-implant systems. We discuss their advantages and disadvantages and how they could improve the survival and integration of the implanted cells.

Biotechnology and Biomaterial-Based Therapeutic Strategies for Age-Related Macular Degeneration. Part I: Biomaterials-Based Drug Delivery Devices.

Age-related Macular Degeneration (AMD) is an up-to-date untreatable chronic neurodegenerative eye disease of multifactorial origin, and the main causes of blindness in over 65 years old people. It is characterized by a slow progression and the presence of a multitude of factors, highlighting those related to diet, genetic heritage and environmental conditions, present throughout each of the stages of the illness. Current therapeutic approaches, mainly consisting of intraocular drug delivery, are only used for symptoms relief and/or to decelerate the progression of the disease. Furthermore, they are overly simplistic and ignore the complexity of the disease and the enormous differences in the symptomatology between patients. Due to the wide impact of the AMD and the up-to-date absence of clinical solutions, the development of biomaterials-based approaches for a personalized and controlled delivery of therapeutic drugs and biomolecules represents the main challenge for the defeat of this neurodegenerative disease. Here we present a critical review of the available and under development AMD therapeutic approaches, from a biomaterials and biotechnological point of view. We highlight benefits and limitations and we forecast forthcoming alternatives based on novel biomaterials and biotechnology methods. In the first part we expose the physiological and clinical aspects of the disease, focusing on the multiple factors that give origin to the disorder and highlighting the contribution of these factors to the triggering of each step of the disease. Then we analyze available and under development biomaterials-based drug-delivery devices (DDD), taking into account the anatomical and functional characteristics of the healthy and ill retinal tissue.

MicroRNAs in neurodegenerative eye disease

Introduction: Neurodegenerative diseases affect the central nervous system and cause progressive dysfunction. These debilitating and incurable conditions are characterized by loss of neuronal cell function and are often associated with atrophy of the affected nervous system structures. The retina and the optic nerve are considered an extension of the central nervous system due to their embryonic origin and myelination by oligodendrocytes. Thereby, common physiopathological mechanism may be implicated in the neurodegeneration progress, regulated by key molecules as microRNAs. Aim: To determine the expression profile of microRNAs in peripheral blood in patients with neurodegenerative eye diseases such Glaucoma and Alzheimer´s disease. Methods: Observational, multicentric, comparative study. 50 patients distributed into four groups were included for this study: 10 (20%) with Alzheimer's disease, 20 (40%) with Glaucoma and 20 (40%) healthy control individuals. Results: miR-155 was found to be with tendency to overexpression in the Glaucoma group. miR-483 was found to be significatively overexpressed by five times in the Glaucoma group compared to control individuals. No significant changes were observed for Alzheimer’s disease group in both microRNAs. Conclusion: The preliminary results observed in this study, may suggest that the miR155 and miR483 microRNAs show peripheral blood levels that can be measured in a repeatable and reliable way, this opens the way to a new route of early diagnosis and possible treatment for neurodegenerative eye disease like glaucoma.

Ginkgo Biloba Extract in Ophthalmic and Systemic Disease, With a Focus on Normal-Tension Glaucoma.

Glaucoma is a neurodegenerative eye disease that results in retinal ganglion cell loss and ultimately loss of vision. Elevated intraocular pressure (IOP) is the most common known risk factor for retinal ganglion cell damage and visual field loss, and the only modifiable risk factor proven to reduce the development and progression of glaucoma. This has greatly influenced our approach and assessment in terms of diagnosis and treatment. However, as many as ≥50% of patients with progressive vision loss from primary open angle glaucoma without IOP elevation (≤22 mm Hg) have been reported in the United States and Canada; 90% in Japan and 80% in Korea. Extensive research is currently underway to identify the etiology of risk factors for glaucoma other than or in addition to elevated IOP (so-called “normal-tension” glaucoma; NTG) and use this knowledge to expand available treatment options. Currently, Food and Drug Administration-approved medications for glaucoma exclusively target elevated IOP, suggesting the need for additional approaches to treatment options beyond the current scope as the definition of glaucoma changes to encompass cellular and molecular mechanisms. This review focuses on alternative medical approaches, specifically Ginkgo Biloba extract, as a potential treatment option for normal-tension glaucoma.

Extracellular Signal-Regulated Kinase 1/2 Pathway Is Insufficiently Involved in the Neuroprotective Effect by Hydrogen Sulfide Supplement in Experimental Glaucoma.

Glaucoma is a neurodegenerative eye disease characterized by gradually impaired visual field and irreversible blindness due to retinal ganglion cell (RGC) loss. Our previous studies have confirmed that hydrogen sulfide (H2S) takes part in the glaucomatous process and contributes to RGC protection. The present study aimed to further investigate the role of extracellular signal-regulated kinase 1/2 (ERK 1/2) pathway underlying the impact of H2S, to better understand the mechanism through which H2S exerts neuroprotection in glaucoma. An established rat glaucoma model was used and 168 rats were qualified to undergo sodium hydrosulfide (NaHS, a H2S donor)/PD98059 (an ERK inhibitor) treatment. Then the survival and apoptosis of RGC were evaluated through retrograde labeling and TUNEL staining, along with activity evaluations of ERK 1/2 pathway, intrinsic apoptotic pathway, glial activation, nuclear factor kappa B (NF-κB) pathway, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, autophagy, and TNF-α production through immunohistochemistry, Western blotting, and ELISA. The study demonstrated that NaHS suppressed ERK 1/2 pathway activity similarly to PD98059 in retinas of experimental glaucoma rats, while PD98059 also similarly suppressed glial activation, NF-κB pathway, NADPH oxidase, and TNF-α production. However, PD98059 did not affect RGC survival, apoptotic regulation, or autophagy as NaHS did. Our study indicated that inhibition of ERK 1/2 pathway might partly contribute to the neuroprotection by H2S in experimental glaucoma; however, it was insufficient to initiate the therapeutic effect on its own.