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Photochemical & Photobiological... Jun 2024Blue light exposure of the ocular apparatus is currently rising. This has motivated a growing concern about potential deleterious effects on different eye structures. To...
Blue light exposure of the ocular apparatus is currently rising. This has motivated a growing concern about potential deleterious effects on different eye structures. To address this, ARPE-19 cells were used as a model of the retinal pigment epithelium and subjected to cumulative expositions of blue light. The most relevant cellular events previously associated with blue-light-induced damage were assessed, including alterations in cell morphology, viability, cell proliferation, oxidative stress, inflammation, and the induction of DNA repair cellular mechanisms. Consistent with previous reports, our results provide evidence of cellular alterations resulting from repeated exposure to blue light irradiation. In this context, we explored the potential protective properties of the vegetal extract from Polypodium leucotomos, Fernblock® (FB), using the widely known treatment with lutein as a reference for comparison. The only changes observed as a result of the sole treatment with either FB or lutein were a slight but significant increase in γH2AX cells and the raise in the nuclear levels of NRF2. Overall, our findings indicate that the treatment with FB (similarly to lutein) prior to blue light irradiation can alleviate blue-light-induced deleterious effects in RPE cells, specifically preventing the drop in both cell viability and percentage of EdU cells, as well as the increase in ROS generation, percentage of γH2AX nuclei (more efficiently with FB), and TNF-α secretion (the latter restored only by FB to similar levels to those of the control). On the contrary, the induction in the P21 expression upon blue light irradiation was not prevented neither by FB nor by lutein. Notably, the nuclear translocation of NRF2 induced by blue light was similar to that observed in cells pre-treated with FB, while lutein pre-treatment resulted in nuclear NRF2 levels similar to control cells, suggesting key differences in the mechanism of cellular protection exerted by these compounds. These results may represent the foundation ground for the use of FB as a new ingredient in the development of alternative prophylactic strategies for blue-light-associated diseases, a currently rising medical interest.
PubMed: 38909335
DOI: 10.1007/s43630-024-00606-6 -
International Immunopharmacology Jun 2024There is growing interest in evaluating the safety and therapeutic potential of existing treatments such as tocilizumab (TCZ), an IL-6 receptor antagonist used to treat...
There is growing interest in evaluating the safety and therapeutic potential of existing treatments such as tocilizumab (TCZ), an IL-6 receptor antagonist used to treat inflammatory diseases. However, there have been reports of increased inflammation in patients with HTLV-1 uveitis after TCZ treatment, and its ocular safety in the HTLV-1 infected state remains unknown. This study focused on assessing the impact of TCZ on HTLV-1-infected ocular cells using an in vitro model in which retinal pigment epithelial cells were cocultured with irradiated HTLV-1-infected T-cell lines. TCZ did not significantly affect cellular viability, inflammatory markers, or HTLV-1 proviral loads at various concentrations (25/50/100 µg/ml), indicating no increased risk of HTLV-1 viral infection and no exacerbation of the inflammatory aspects of HTLV-1 infection in the ocular cells. These promising results support the potential of TCZ as a safe treatment option for HTLV-1-infected patients, particularly those with eye infections.
PubMed: 38908082
DOI: 10.1016/j.intimp.2024.112460 -
Scientific Reports Jun 2024To improve the understanding of potential pathological mechanisms of macular edema (ME), we try to discover biomarker candidates related to ME caused by diabetic...
To improve the understanding of potential pathological mechanisms of macular edema (ME), we try to discover biomarker candidates related to ME caused by diabetic retinopathy (DR) and retinal vein occlusion (RVO) in spectral-domain optical coherence tomography images by means of deep learning (DL). 32 eyes of 26 subjects with non-proliferative DR (NPDR), 77 eyes of 61 subjects with proliferative DR (PDR), 120 eyes of 116 subjects with branch RVO (BRVO), and 17 eyes of 15 subjects with central RVO (CRVO) were collected. A DL model was implemented to guide biomarker candidate discovery. The disorganization of the retinal outer layers (DROL), i.e., the gray value of the retinal tissues between the external limiting membrane (ELM) and retinal pigment epithelium (RPE), the disrupted and obscured rate of the ELM, ellipsoid zone (EZ), and RPE, was measured. In addition, the occurrence, number, volume, and projected area of hyperreflective foci (HRF) were recorded. ELM, EZ, and RPE are more likely to be obscured in RVO group and HRFs are observed more frequently in DR group (all P ≤ 0.001). In conclusion, the features of DROL and HRF can be possible biomarkers related to ME caused by DR and RVO in OCT modality.
Topics: Humans; Macular Edema; Tomography, Optical Coherence; Retinal Vein Occlusion; Diabetic Retinopathy; Female; Male; Biomarkers; Middle Aged; Aged; Retinal Pigment Epithelium; Deep Learning
PubMed: 38906954
DOI: 10.1038/s41598-024-63144-2 -
Scientific Reports Jun 2024Diabetic retinopathy (DR) is a multifactorial disease displaying vascular-associated pathologies, including vascular leakage and neovascularization, ultimately leading...
Diabetic retinopathy (DR) is a multifactorial disease displaying vascular-associated pathologies, including vascular leakage and neovascularization, ultimately leading to visual impairment. However, animal models accurately reflecting these pathologies are lacking. Vascular endothelial growth factor A (VEGF-A) is an important factor in the development of micro- and macro-vascular pathology in DR. In this study, we evaluated the feasibility of using a cumate-inducible lentivirus (LV) mediated expression of vegf-a to understand DR pathology in vitro and in vivo. Retinal pigment epithelial cells (ARPE-19) were transduced with cumate-inducible LV expressing vegf-a, with subsequent analysis of vegf-a expression and its impact on cell proliferation, viability, motility, and permeability. Cumate tolerability in adult Wistar rat eyes was assessed as an initial step towards a potential DR animal model development, by administering cumate via intravitreal injections (IVT) and evaluating consequent effects by spectral domain optical coherence tomography (SD-OCT), flash electroretinography (fERG), ophthalmic examination (OE), and immunohistochemistry. Transduction of ARPE-19 cells with cumate-inducible LV resulted in ~ 2.5-fold increase in vegf-a mRNA and ~ threefold increase in VEGF-A protein secretion. Transduced cells displayed enhanced cell proliferation, viability, permeability, and migration in tube-like structures. However, IVT cumate injections led to apparent retinal toxicity, manifesting as retinal layer abnormalities, haemorrhage, vitreous opacities, and significant reductions in a- and b-wave amplitudes, along with increased microglial activation and reactive gliosis. In summary, while cumate-inducible LV-mediated vegf-a expression is valuable for in vitro mechanistic studies in cellular drug discovery, its use is not a feasible approach to model DR in in vivo studies due to cumate-induced retinal toxicity.
Topics: Animals; Vascular Endothelial Growth Factor A; Diabetic Retinopathy; Lentivirus; Rats; Retinal Pigment Epithelium; Humans; Rats, Wistar; Cell Proliferation; Disease Models, Animal; Cell Line; Intravitreal Injections; Male; Cell Movement; Cell Survival; Tomography, Optical Coherence; Genetic Vectors
PubMed: 38906906
DOI: 10.1038/s41598-024-63590-y -
Investigative Ophthalmology & Visual... Jun 2024Recent studies have shown that the retinal pigment epithelium (RPE) relies on fatty acid oxidation (FAO) for energy, however, its role in overall retinal health is...
PURPOSE
Recent studies have shown that the retinal pigment epithelium (RPE) relies on fatty acid oxidation (FAO) for energy, however, its role in overall retinal health is unknown. The only FAO disorder that presents with chorioretinopathy is long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD). Studying the molecular mechanisms can lead to new treatments for patients and elucidate the role of FAO in the RPE. This paper characterizes the chorioretinopathy progression in a recently reported LCHADD mouse model.
METHODS
Visual assessments, such as optokinetic tracking and fundus imaging, were performed in wildtype (WT) and LCHADD mice at 3, 6, 10, and 12 months of age. Retinal morphology was analyzed in 12-month retinal cross-sections using hematoxylin and eosin (H&E), RPE65, CD68, and TUNEL staining, whereas RPE structure was assessed using transmission electron microscopy (TEM). Acylcarnitine profiles were measured in isolated RPE/sclera samples to determine if FAO was blocked. Bulk RNA-sequencing of 12 month old male WT mice and LCHADD RPE/sclera samples assessed gene expression changes.
RESULTS
LCHADD RPE/sclera samples had a 5- to 7-fold increase in long-chain hydroxyacylcarnitines compared to WT, suggesting an impaired LCHAD step in long-chain FAO. LCHADD mice have progressively decreased visual performance and increased RPE degeneration starting at 6 months. LCHADD RPE have an altered structure and a two-fold increase in macrophages in the subretinal space. Finally, LCHADD RPE/sclera have differentially expressed genes compared to WT, including downregulation of genes important for RPE function and angiogenesis.
CONCLUSIONS
Overall, this LCHADD mouse model recapitulates early-stage chorioretinopathy seen in patients with LCHADD and is a useful model for studying LCHADD chorioretinopathy.
Topics: Animals; Disease Models, Animal; Mice; Retinal Pigment Epithelium; Mice, Inbred C57BL; Long-Chain-3-Hydroxyacyl-CoA Dehydrogenase; Choroid Diseases; Male; Retinal Diseases; Microscopy, Electron, Transmission
PubMed: 38904639
DOI: 10.1167/iovs.65.6.33 -
Bioscience Reports Jun 2024
Expression of Concern: Madecassoside protects retinal pigment epithelial cells against hydrogen peroxide induced oxidative stress and apoptosis through the activation of Nrf2/HO-1 pathway.
Topics: NF-E2-Related Factor 2; Oxidative Stress; Hydrogen Peroxide; Apoptosis; Humans; Heme Oxygenase-1; Retinal Pigment Epithelium; Signal Transduction; Triterpenes; Epithelial Cells; Cell Line; Membrane Proteins; Animals
PubMed: 38904175
DOI: 10.1042/BSR-2019-4347_EOC -
Cureus May 2024Congenital simple hamartoma of the retinal pigment epithelium (CSHRPE) is a rare benign tumor often detected incidentally during routine eye exams. We present a case of...
Congenital simple hamartoma of the retinal pigment epithelium (CSHRPE) is a rare benign tumor often detected incidentally during routine eye exams. We present a case of multifocal CSHRPE in a 32-year-old Hispanic woman, emphasizing the diagnostic challenges posed by its presentation and the pivotal role of multimodal imaging in accurate diagnosis. Despite initial difficulties due to a history of trauma and pigmented fundus, advanced imaging techniques, including optical coherence tomography (OCT), OCT angiography (OCTA), fluorescein angiography (FA), and indocyanine green angiography (ICGA), facilitated a precise diagnosis. Notably, OCTA revealed high signal intensity and flow at the largest nodule site while FA and ICGA exhibited characteristic blockage patterns. Moreover, smaller nodules exhibited OCT findings supporting the theory of islands of retinal pigment epithelium (RPE) cells proliferating ectopically within the retina. Our case underscores the importance of comprehensive imaging assessment in distinguishing CSHRPE from other lesions, contributing to a deeper understanding of this rare ocular condition.
PubMed: 38903341
DOI: 10.7759/cureus.60755 -
Canadian Journal of Ophthalmology.... Jun 2024To compare the visibility and accessibility of the outer retina in neovascular age-related macular degeneration (nAMD) between 2 OCT devices.
OBJECTIVE
To compare the visibility and accessibility of the outer retina in neovascular age-related macular degeneration (nAMD) between 2 OCT devices.
METHODS
In this prospective, cross-sectional exploratory study, differences in thickness and loss of individual outer retinal layers in eyes with nAMD and in age-matched healthy eyes between a next-level High-Res OCT device and the conventional SPECTRALIS OCT (both Heidelberg Engineering GmbH, Heidelberg, Germany) were analyzed. Eyes with nAMD and at least 250 nL of retinal fluid, quantified by an approved deep-learning algorithm (Fluid Monitor, RetInSight, Vienna, Austria), fulfilled the inclusion criteria. The outer retinal layers were segmented using automated layer segmentation and were corrected manually. Layer loss and thickness were compared between both devices using a linear mixed-effects model and a paired t test.
RESULTS
Nineteen eyes of 17 patients with active nAMD and 17 healthy eyes were included. For nAMD eyes, the thickness of the retinal pigment epithelium (RPE) differed significantly between the devices (25.42 μm [95% CI, 14.24-36.61] and 27.31 μm [95% CI, 16.12-38.50] for high-resolution OCT and conventional OCT, respectively; p = 0.033). Furthermore, a significant difference was found in the mean relative external limiting membrane loss (p = 0.021). However, the thickness of photoreceptors, RPE integrity loss, and photoreceptor integrity loss did not differ significantly between devices in the central 3 mm. In healthy eyes, a significant difference in both RPE and photoreceptor thickness between devices was shown (p < 0.001).
CONCLUSION
Central RPE thickness was significantly thinner on high-resolution OCT compared with conventional OCT images explained by superior optical separation of the RPE and Bruch's membrane.
PubMed: 38901467
DOI: 10.1016/j.jcjo.2024.05.014 -
Retina (Philadelphia, Pa.) Jul 2024To describe the progression from outer retinal neovascularization (ORNV) to exudative subretinal new vessels (SRNVs) in idiopathic macular telangiectasia type 2.
PURPOSE
To describe the progression from outer retinal neovascularization (ORNV) to exudative subretinal new vessels (SRNVs) in idiopathic macular telangiectasia type 2.
METHODS
A total of 135 patients (270 eyes) imaged with optical coherence tomography angiography were included.
MAIN OUTCOME MEASURES
Ellipsoid zone loss, outer retinal hyperreflectivity, ORNV, and SRNVs. Outer retinal neovascularization was defined as a flow signal passing through the outer plexiform layer, with or without vertical linear outer retinal hyperreflectivity on the optical coherence tomography B-scan. Subretinal new vessels were defined as an abnormal capillary network with a peripheral anastomotic arcade seen on en face optical coherence tomography angiography and a convex hyperreflectivity at the retinal pigment epithelium.
RESULTS
Subretinal new vessels were observed in 38/270 eyes (14%). Subretinal new vessels were at a fibrotic stage in 24/38 eyes and at an exudative stage in 6/38 eyes, and a progression from ORNV to SRNVs was documented in 8/38 eyes. All cases showed an ellipsoid zone loss. In seven eyes (2.5%), SRNVs were also associated with subepithelial neovascularization. No retinochoroidal anastomosis was detected. The visual acuity dropped when SRNVs were present.
CONCLUSION
In this case series, SRNVs were found in 14% of eyes. In all cases, they were associated with an ellipsoid zone loss and with outer retinal hyperreflectivity. A progression from ORNV to SRNVs was observed.
Topics: Humans; Tomography, Optical Coherence; Female; Male; Retinal Neovascularization; Fluorescein Angiography; Aged; Middle Aged; Retinal Telangiectasis; Visual Acuity; Retinal Vessels; Retrospective Studies; Fundus Oculi; Disease Progression; Retinal Pigment Epithelium; Aged, 80 and over; Adult
PubMed: 38900579
DOI: 10.1097/IAE.0000000000004079 -
Nature Communications Jun 2024Phototransduction involves changes in concentration of ions and other solutes within photoreceptors and in subretinal space, which affect osmotic pressure and the...
Phototransduction involves changes in concentration of ions and other solutes within photoreceptors and in subretinal space, which affect osmotic pressure and the associated water flow. Corresponding expansion and contraction of cellular layers can be imaged using optoretinography (ORG), based on phase-resolved optical coherence tomography (OCT). Until now, ORG could reliably detect only photoisomerization and phototransduction in photoreceptors, primarily in cones under bright stimuli. Here, by employing a phase-restoring subpixel motion correction algorithm, which enables imaging of the nanometer-scale tissue dynamics during minute-long recordings, and unsupervised learning of spatiotemporal patterns, we discover optical signatures of the other retinal structures' response to visual stimuli. These include inner and outer segments of rod photoreceptors, retinal pigment epithelium, and subretinal space in general. The high sensitivity of our technique enables detection of the retinal responses to dim stimuli: down to 0.01% bleach level, corresponding to natural levels of scotopic illumination. We also demonstrate that with a single flash, the optoretinogram can map retinal responses across a 12° field of view, potentially replacing multifocal electroretinography. This technique expands the diagnostic capabilities and practical applicability of optoretinography, providing an alternative to electroretinography, while combining structural and functional retinal imaging in the same OCT machine.
Topics: Tomography, Optical Coherence; Animals; Retinal Pigment Epithelium; Retinal Rod Photoreceptor Cells; Retina; Light; Photic Stimulation; Algorithms; Male
PubMed: 38898002
DOI: 10.1038/s41467-024-49014-5