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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 -
Journal of Agricultural and Food... Jul 2024Excessive hydrogen peroxide (HO) generated during retinal cell metabolic activity could lead to oxidative degeneration of retinal pigment epithelium (RPE) tissue, a...
Excessive hydrogen peroxide (HO) generated during retinal cell metabolic activity could lead to oxidative degeneration of retinal pigment epithelium (RPE) tissue, a specific pathological process implicated in various retinal diseases resulting in blindness, which can be mitigated by taking dietary antioxidants to prevent inflammation and impaired cellular dysfunction. This study tested the hypothesis that damages induced by oxidative stresses can be mitigated by lutein in a HO-challenged model, which was based on an ARPE-19 cell monolayer cultured on three-dimensional (3D)-printed fibrous scaffolds. Pretreating these models with lutein (0.5 μM) for 24 h can significantly lower the oxidative stress and maintain phagocytosis and barrier function. Moreover, lutein can modulate the NLRP3 inflammasome, leading to a ∼40% decrease in the pro-inflammatory cytokine (IL-1β and IL-18) levels. Collectively, this study suggests that the 3D RPE model is an effective tool to examine the capability of lutein to modulate cellular functionalities and regulate NLRP3 inflammation.
Topics: Retinal Pigment Epithelium; NLR Family, Pyrin Domain-Containing 3 Protein; Humans; Inflammasomes; Hydrogen Peroxide; Lutein; Oxidative Stress; Cell Line; Interleukin-1beta; Interleukin-18; Models, Biological
PubMed: 38897610
DOI: 10.1021/acs.jafc.4c01537 -
International Journal of Ophthalmology 2024To evaluate the effect of auraptene (AUR) treatment in forms of free and encapsulated in niosome nanoparticles by investigating the mRNA expression level of vascular...
AIM
To evaluate the effect of auraptene (AUR) treatment in forms of free and encapsulated in niosome nanoparticles by investigating the mRNA expression level of vascular endothelium growth factor (VEGF)-A and platelet-derived growth factors (PDGFs) in human retinal pigment epithelium (RPE) cell line.
METHODS
Niosome nanocarriers were produced using two surfactants Span 60 and Tween 80. RPE cell line was treated with both free AUR and niosome-encapsulated. Optimum dosage of treatments was calculated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression of and , , , genes was measured after total RNA extraction and cDNA synthesis, using real-time polymerase chain reaction (RT-PCR).
RESULTS
The highest entrapment efficiency (EE) was achieved by Span 60:cholesterol (1:1) with 64.3%. The half maximal inhibitory concentration (IC) of free and niosome-encapsulated AUR were 38.5 and 27.78 µg/mL, respectively. Release study revealed that niosomal AUR had more gradual delivery to the cells. RT-PCR results showed reduced expression levels of , , , , and after treatment with both free and niosomal AUR.
CONCLUSION
Niosomal formulation of Span 60: cholesterol (1:1) is an effective drug delivery approach to transfer AUR to RPE cells. VEGF-A, PDGF-A, PDGF-B, PDGF-C, and PDGF-D are four angiogenic factors, inhibiting which by niosomal AUR may be effective in age-related macular degeneration.
PubMed: 38895680
DOI: 10.18240/ijo.2024.06.06 -
International Journal of Ophthalmology 2024To explore the effect of epidermal growth factor receptor (EGFR) inhibition by erlotinib and EGFR siRNA on epidermal growth factor (EGF)-induced activation of retinal...
AIM
To explore the effect of epidermal growth factor receptor (EGFR) inhibition by erlotinib and EGFR siRNA on epidermal growth factor (EGF)-induced activation of retinal pigment epithelium (RPE) cells.
METHODS
Human RPE cell line (ARPE-19 cells) was activated by 100 ng/mL EGF. Erlotinib and EGFR siRNA were used to intervene EGF treatment. Cellular viability, proliferation, and migration were detected by methyl thiazolyl tetrazolium (MTT) assay, bromodeoxyuridine (BrdU) staining assay and wound healing assay, respectively. EGFR/protein kinase B (AKT) pathway proteins and N-cadherin, α-smooth muscle actin (α-SMA), and vimentin were tested by Western blot assay. EGFR was also determined by immunofluorescence staining.
RESULTS
EGF treatment for 24h induced a significant increase of ARPE-19 cells' viability, proliferation and migration, phosphorylation of EGFR/AKT proteins, and decreased total EGFR expression. Erlotinib suppressed ARPE-19 cells' viability, proliferation and migration through down regulating total EGFR and AKT protein expressions. Erlotinib also inhibited EGF-induced an increase of proliferative and migrative ability in ARPE-19 cells and clearly suppressed EGF-induced EGFR/AKT proteins phosphorylation and decreased expression of N-cadherin, α-SMA, and vimentin proteins. Similarly, EGFR inhibition by EGFR siRNA significantly affected EGF-induced an increase of cell proliferation, viability, and migration, phosphorylation of EGFR/AKT proteins, and up-regulation of N-cadherin, α-SMA, and vimentin proteins.
CONCLUSION
Erlotinib and EGFR-knockdown suppress EGF-induced cell viability, proliferation, and migration EGFR/AKT pathway in RPE cells. EGFR inhibition may be a possible therapeutic approach for proliferative vitreoretinopathy (PVR).
PubMed: 38895677
DOI: 10.18240/ijo.2024.06.05 -
BioRxiv : the Preprint Server For... Jun 2024Mutations in the ( gene are associated with inherited, non-syndromic vision loss. Here, we used CRISPR/Cas9 to induce truncating -null mutations in to create a disease...
Mutations in the ( gene are associated with inherited, non-syndromic vision loss. Here, we used CRISPR/Cas9 to induce truncating -null mutations in to create a disease model. We then tracked progression of retinal degeneration in these animals from the ages of 6 weeks to 3 years old. We found that retinal degeneration caused by -null is age-dependent and likely involves death or damage to the retinal pigment epithelium (RPE) that precedes photoreceptor degeneration. As -null frogs age, they develop large cellular debris deposits in the subretinal space and outer segment layer which resemble subretinal drusenoid deposits (SDD) in their location, histology, and representation in color fundus photography and optical coherence tomography (OCT). In older frogs, these SDD-like deposits accumulate in size and number, and they are present before retinal degeneration occurs. Evidence for an RPE origin of these deposits includes infiltration of pigment granules into the deposits, thinning of RPE as measured by OCT, and RPE disorganization as measured by histology and OCT. The appearance and accumulation of SDD-like deposits and RPE thinning and disorganization in our animal model suggests an underlying disease mechanism for -null mediated blindness of death and dysfunction of the RPE preceding photoreceptor degeneration, instead of direct effects upon photoreceptor outer segment morphogenesis, as was previously hypothesized.
PubMed: 38895468
DOI: 10.1101/2024.06.03.597229