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PURPOSE: To evaluate the feasibility and safety of intravitreal injection of autologous CD34+ stem cells from bone marrow (BMSCs) in eyes with vision loss from retinitis pigmentosa (RP). DESIGN: Phase I prospective, open-label, single-center study. PARTICIPANTS: Seven eyes (7 patients) with RP with best-corrected visual acuity (BCVA) of 20/60 to 20/400 or visual field constriction to within 10°. METHODS: A comprehensive examination with ETDRS BCVA, macular OCT, perimetry, and fluorescein angiography was performed at baseline, 1 to 3 months, and 6 months after study treatment. Bone marrow aspiration, isolation of CD34+ BMSCs under good manufacturing practice conditions, and intravitreal cell injection were performed on the same day. The CD34+ cells were isolated from bone marrow using a Ficoll gradient and the Miltenyi CliniMACS system. Isolated CD34+ cells were released for clinical use if viability, sterility, and purity met the release criteria accepted by the United States Food and Drug Administration for this clinical study. MAIN OUTCOME MEASURES: Number of CD34+ cells isolated for injection and adverse events associated with study treatment during follow-up. Secondary outcome measures are changes in BCVA and perimetry. RESULTS: All isolated CD34+ cells passed the release criteria. A mean of 3.26 ± 0.66 million viable CD34+ cells (range 1.6 to 7.05 million) were injected intravitreally per eye. No adverse event was noted during the study follow-up except for 1 participant who was noted with transient cells in the anterior chamber with mild elevation in intraocular pressure at 18 hours after study injection which normalized by 24 hours. Best-corrected visual acuity remained within 2 lines of baseline or improved in all participants at 6 months follow-up. Perimetry was stable or improved in all eyes during study follow-up except 1 eye with transient improvement at 1 month and worsening of both eyes at 6 months. CONCLUSIONS: Intravitreal injection of autologous CD34+ BMSCs is feasible and appears to be well tolerated in eyes with vision loss from RP. A larger randomized prospective study would be needed to evaluate further the safety and potential efficacy of this cell therapy for vision loss associated with RP. FINANCIAL DISCLOSURES: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Photoreceptor degeneration is a major cause of untreatable blindness worldwide and has recently been targeted by emerging technologies, including cell- and gene-based therapies. Cell types of neural lineage have shown promise for replacing either photoreceptors or retinal pigment epithelial cells following delivery to the subretinal space, while cells of bone marrow lineage have been tested for retinal trophic effects following delivery to the vitreous cavity. Here we explore an alternate approach in which cells from the immature neural retinal are delivered to the vitreous cavity with the goal of providing trophic support for degenerating photoreceptors. Rat and human retinal progenitor cells were transplanted to the vitreous of rats with a well-studied photoreceptor dystrophy, resulting in substantial anatomical preservation and functional rescue of vision. This work provides scientific proof-of-principle for a novel therapeutic approach to photoreceptor degeneration that is currently being evaluated in clinical trials.

Vacuolar protein sorting 35 (VPS35), the core component of the retromer complex which regulates endosomal trafficking, is genetically linked with Parkinson's disease (PD). Impaired vision is a common non-motor manifestation of PD. Here, we show mouse retinas with VPS35-deficient rods exhibit synapse loss and visual deficit, followed by progressive degeneration concomitant with the emergence of Lewy body-like inclusions and phospho-α-synuclein (P-αSyn) aggregation. Ultrastructural analyses reveal VPS35-deficient rods accumulate aggregates in late endosomes, deposited as lipofuscins bound to P-αSyn. Mechanistically, we uncover a protein network of VPS35 and its interaction with HSC70. VPS35 deficiency promotes sequestration of HSC70 and P-αSyn aggregation in late endosomes. Microglia which engulf lipofuscins and P-αSyn aggregates are activated, displaying autofluorescence, observed as bright dots in fundus imaging of live animals, coinciding with pathology onset and progression. The Rod∆Vps35 mouse line is a valuable tool for further mechanistic investigation of αSyn lesions and retinal degenerative diseases.

MicroRNAs (miRs) are short, evolutionarily conserved noncoding RNAs that canonically downregulate expression of target genes. The miR family composed of miR-204 and miR-211 is among the most highly expressed miRs in the retinal pigment epithelium (RPE) in both mouse and human and also retains high sequence identity. To assess the role of this miR family in the developed mouse eye, we generated two floxed conditional KO mouse lines crossed to the RPE65-ERT2-Cre driver mouse line to perform an RPE-specific conditional KO of this miR family in adult mice. After Cre-mediated deletion, we observed retinal structural changes by optical coherence tomography; dysfunction and loss of photoreceptors by retinal imaging; and retinal inflammation marked by subretinal infiltration of immune cells by imaging and immunostaining. Single-cell RNA sequencing of diseased RPE and retinas showed potential miR-regulated target genes, as well as changes in noncoding RNAs in the RPE, rod photoreceptors, and Müller glia. This work thus highlights the role of miR-204 and miR-211 in maintaining RPE function and how the loss of miRs in the RPE exerts effects on the neural retina, leading to inflammation and retinal degeneration.

Mutations in the adiponectin receptor 1 gene (AdipoR1) lead to retinitis pigmentosa and are associated with age-related macular degeneration. This study explores the effects of AdipoR1 gene deficiency in mice, revealing a striking decline in ω3 polyunsaturated fatty acids (PUFA), an increase in ω6 fatty acids, and elevated ceramides in the retina. The AdipoR1 deficiency impairs peroxisome proliferator-activated receptor α signaling, which is crucial for FA metabolism, particularly affecting proteins associated with FA transport and oxidation in the retina and retinal pigmented epithelium. Our lipidomic and proteomic analyses indicate changes that could affect membrane composition and viscosity through altered ω3 PUFA transport and synthesis, suggesting a potential influence of AdipoR1 on these properties. Furthermore, we noted a reduction in the Bardet-Biedl syndrome proteins, which are crucial for forming and maintaining photoreceptor outer segments that are PUFA-enriched ciliary structures. Diminution in Bardet-Biedl syndrome-proteins content combined with our electron microscopic observations raises the possibility that AdipoR1 deficiency might impair ciliary function. Treatment with inhibitors of ceramide synthesis led to substantial elevation of ω3 LC-PUFAs, alleviating photoreceptor degeneration and improving retinal function. These results serve as the proof of concept for a ceramide-targeted strategy to treat retinopathies linked to PUFA deficiency, including age-related macular degeneration.

Retinal prosthetics are one of the leading therapeutic strategies to restore lost vision in patients with retinitis pigmentosa and age-related macular degeneration. Much work has described patterns of spiking in retinal ganglion cells (RGCs) in response to electrical stimulation, but less work has examined the underlying retinal circuitry that is activated by electrical stimulation to drive these responses. Surprisingly, little is known about the role of inhibition in generating electrical responses or how inhibition might be altered during degeneration. Using whole-cell voltage-clamp recordings during subretinal electrical stimulation in the rd10 and wild-type (wt) retina, we found electrically evoked synaptic inputs differed between ON and OFF RGC populations, with ON cells receiving mostly excitation and OFF cells receiving mostly inhibition and very little excitation. We found that the inhibition of OFF bipolar cells limits excitation in OFF RGCs, and a majority of both pre- and postsynaptic inhibition in the OFF pathway arises from glycinergic amacrine cells, and the stimulation of the ON pathway contributes to inhibitory inputs to the RGC. We also show that this presynaptic inhibition in the OFF pathway is greater in the rd10 retina, compared with that in the wt retina.

Because derivation of retinal organoids (ROs) and transplantation are frequently split between geographically distant locations, we developed a special shipping device and protocol capable of the organoids' delivery to any location. Human embryonic stem cell (hESC)-derived ROs were differentiated from the hESC line H1 (WA01), shipped overnight to another location, and then transplanted into the subretinal space of blind immunodeficient retinal degeneration (RD) rats. Development of transplants was monitored by spectral-domain optical coherence tomography. Visual function was accessed by optokinetic tests and superior colliculus (SC) electrophysiology. Cryostat sections through transplants were stained with hematoxylin and eosin; or processed for immunohistochemistry to label human donor cells, retinal cell types, and synaptic markers. After transplantation, ROs integrated into the host RD retina, formed functional photoreceptors, and improved vision in rats with advanced RD. The survival and vision improvement are comparable with our previous results of hESC-ROs without a long-distance delivery. Furthermore, for the first time in the stem cell transplantation field, we demonstrated that the response heatmap on the SC showed a similar shape to the location of the transplant in the host retina, which suggested the point-to-point projection of the transplant from the retina to SC. In conclusion, our results showed that using our special device and protocol, the hESC-derived ROs can be shipped over long distance and are capable of survival and visual improvement after transplantation into the RD rats. Our data provide a proof-of-concept for stem cell replacement as a therapy for RD patients.

PURPOSE: To describe and evaluate a novel method to determine the validity of measurements made using cycle-by-cycle (CxC) recording techniques in patients with advanced retinal degenerations (RD) having low-amplitude flicker electroretinogram (ERG) responses. METHODS: The method extends the original CxC recording algorithm introduced by Sieving et al., retaining the original recording setup and the preliminary analysis of raw data. Novel features include extended use of spectrum analysis, reduction of errors due to known sources, and a comprehensive statistical assessment using three different tests. The method was applied to ERG recordings from seven patients with RD and two patients with CNGB3 achromatopsia. RESULTS: The method was implemented as a Windows application to processes raw data obtained from a commercial ERG system, and it features a computational toolkit for statistical assessment of ERG recordings with amplitudes as low as 1 µV, commonly found in advanced RD patients. When recorded using conditions specific for eliciting cone responses, none of the CNGB3 patients had a CxC validated response, indicating that no signal artifacts were present with our recording conditions. A comparison of the presented method with conventional 30 Hz ERG was performed. Bland-Altman plots indicated good agreement (mean difference, -0.045 µV; limits of agreement, 0.193 to -0.282 µV) between the resulting amplitudes. Within-session test-retest variability was 15%, comparing favorably to the variability of standard ERG amplitudes. CONCLUSIONS: This novel method extracts highly reliable clinical recordings of low-amplitude flicker ERGs and effectively detects artifactual responses. It has potential value both as a cone outcome variable and planning tool in clinical trials on natural history and treatment of advanced RDs.

Inherited retinopathies are devastating diseases that in most cases lack treatment options. Disease-modifying therapies that mitigate pathophysiology regardless of the underlying genetic lesion are desirable due to the diversity of mutations found in such diseases. We tested a systems pharmacology-based strategy that suppresses intracellular cAMP and Ca2+ activity via G protein-coupled receptor (GPCR) modulation using tamsulosin, metoprolol, and bromocriptine coadministration. The treatment improves cone photoreceptor function and slows degeneration in Pde6βrd10 and RhoP23H/WT retinitis pigmentosa mice. Cone degeneration is modestly mitigated after a 7-month-long drug infusion in PDE6A-/- dogs. The treatment also improves rod pathway function in an Rpe65-/- mouse model of Leber congenital amaurosis but does not protect from cone degeneration. RNA-sequencing analyses indicate improved metabolic function in drug-treated Rpe65-/- and rd10 mice. Our data show that catecholaminergic GPCR drug combinations that modify second messenger levels via multiple receptor actions provide a potential disease-modifying therapy against retinal degeneration.

Age‐related macular degeneration (AMD) is an emerging cause of blindness in aged people worldwide. One of the key signs of AMD is the degeneration of the retinal pigment epithelium (RPE), which is indispensable for the maintenance of the adjacent photoreceptors. Because of impaired energy metabolism resulting from constant light exposure, hypoxia, and oxidative stress, accumulation of drusen in AMD‐affected eyes is observed. Drusen contain damaged cellular proteins, lipoprotein particles, lipids and carbohydrates and they are related to impaired protein clearance, inflammation, and extracellular matrix modification. When autophagy, a major cellular proteostasis pathway, is impaired, the accumulations of intracellular lipofuscin and extracellular drusen are detected. As these aggregates grow over time, they finally cause the disorganisation and destruction of the RPE and photoreceptors leading to visual loss. In this review, the role of autophagy in drusen biogenesis is discussed since impairment in removing cellular waste in RPE cells plays a key role in AMD progression. In the future, means which improve intracellular clearance might be of use in AMD therapy to slow the progression of drusen formation. [ABSTRACT FROM AUTHOR]

High intraocular pressure causes retinal ganglion cell injury in primary and secondary glaucoma diseases, yet the molecular landscape characteristics of retinal cells under high intraocular pressure remain unknown. Rat models of acute hypertension ocular pressure were established by injection of cross-linked hyaluronic acid hydrogel (Healaflow®). Single-cell RNA sequencing was then used to describe the cellular composition and molecular profile of the retina following high intraocular pressure. Our results identified a total of 12 cell types, namely retinal pigment epithelial cells, rod-photoreceptor cells, bipolar cells, Müller cells, microglia, cone-photoreceptor cells, retinal ganglion cells, endothelial cells, retinal progenitor cells, oligodendrocytes, pericytes, and fibroblasts. The single-cell RNA sequencing analysis of the retina under acute high intraocular pressure revealed obvious changes in the proportions of various retinal cells, with ganglion cells decreased by 23%. Hematoxylin and eosin staining and TUNEL staining confirmed the damage to retinal ganglion cells under high intraocular pressure. We extracted data from retinal ganglion cells and analyzed the retinal ganglion cell cluster with the most distinct expression. We found upregulation of the B3gat2 gene, which is associated with neuronal migration and adhesion, and downregulation of the Tsc22d gene, which participates in inhibition of inflammation. This study is the first to reveal molecular changes and intercellular interactions in the retina under high intraocular pressure. These data contribute to understanding of the molecular mechanism of retinal injury induced by high intraocular pressure and will benefit the development of novel therapies. [ABSTRACT FROM AUTHOR]

Retinitis Pigmentosa (RP) is a heterogenous group of inherited disorder, and its progression not only affects the retina but also the primary visual cortex. This manifests imbalances in the excitatory and inhibitory neurotransmission. Here, we investigated if changes in cortical functioning is linked to alterations in GABAergic population of neurons and its two important subsets, somatostatin (SST) and parvalbumin (PV) neuron in rd1 model of retinal degeneration (RD). We demonstrate marked decrease in the proportion of SST neurons in different layers of cortex whereas PV neurons were less affected. Moreover, we found reduced expression of glutamatergic thalamic afferents (VGLUT2) due to lack of visual activity. These results suggest PV neurons are likely recruited by the cortical circuitry to increase the inhibitory drive and compensate the disrupted inhibition-excitation balance. However, reduced SST expression perhaps results in weakening of stimulus selectivity. Delineating their functional role during RD will provide insights for acquisition of high-resolution vision thereby improving current state of vision restoration. [ABSTRACT FROM AUTHOR]

Inherited retinal diseases (IRDs) represent a diverse group of genetic disorders leading to progressive degeneration of the retina due to mutations in over 280 genes. This review focuses on the various methodologies for the preclinical characterization and evaluation of adeno-associated virus (AAV)-mediated gene therapy as a potential treatment option for IRDs, particularly focusing on gene therapies targeting mutations, such as those in the RPE65 and FAM161A genes. AAV vectors, such as AAV2 and AAV5, have been utilized to deliver therapeutic genes, showing promise in preserving vision and enhancing photoreceptor function in animal models. Despite their advantages—including high production efficiency, low pathogenicity, and minimal immunogenicity—AAV-mediated therapies face limitations such as immune responses beyond the retina, vector size constraints, and challenges in large-scale manufacturing. This review systematically compares different experimental models used to investigate AAV-mediated therapies, such as mouse models, human retinal explants (HREs), and induced pluripotent stem cell (iPSC)-derived retinal organoids. Mouse models are advantageous for genetic manipulation and detailed investigations of disease mechanisms; however, anatomical differences between mice and humans may limit the translational applicability of results. HREs offer valuable insights into human retinal pathophysiology but face challenges such as tissue degradation and lack of systemic physiological effects. Retinal organoids, on the other hand, provide a robust platform that closely mimics human retinal development, thereby enabling more comprehensive studies on disease mechanisms and therapeutic strategies, including AAV-based interventions. Specific outcomes targeted in these studies include vision preservation and functional improvements of retinas damaged by genetic mutations. This review highlights the strengths and weaknesses of each experimental model and advocates for their combined use in developing targeted gene therapies for IRDs. As research advances, optimizing AAV vector design and delivery methods will be critical for enhancing therapeutic efficacy and improving clinical outcomes for patients with IRDs. [ABSTRACT FROM AUTHOR]

Monoamine neurotransmitters generated by de novo synthesis are rapidly transported and stored into synaptic vesicles at axon terminals. This transport is essential both for sustaining synaptic transmission and for limiting the toxic effects of monoamines. Here, synthesis of the monoamine histamine by histidine decarboxylase (HDC) and subsequent loading of histamine into synaptic vesicles are shown to be physically and functionally coupled within Drosophila photoreceptor terminals. This process requires HDC anchoring to synaptic vesicles via interactions with N-ethylmaleimide-sensitive fusion protein 1 (NSF1). Disassociating HDC from synaptic vesicles disrupts visual synaptic transmission and causes somatic accumulation of histamine, which leads to retinal degeneration. We further identified a proteasome degradation system mediated by the E3 ubiquitin ligase, purity of essence (POE), which clears mislocalized HDC from the soma, thus eliminating the cytotoxic effects of histamine. Taken together, our results reveal a dual mechanism for translocation and degradation of HDC that ensures restriction of histamine synthesis to axonal terminals and at the same time rapid loading into synaptic vesicles. This is crucial for sustaining neurotransmission and protecting against cytotoxic monoamines. Synopsis: Neurotransmitters are key for synaptic transmission at axon terminals, but their transport modalities remain debated. This study demonstrates that coupling of histamine synthesis with its loading into synaptic vesicles by anchoring histidine decarboxylase (HDC) to synaptic vesicles is critical to maintaining neurotransmission and preventing cytotoxic side effects. Coupling histamine synthesis with synaptic vesicle loading is critical for neurotransmitter homeostasis and synaptic transmission. HDC is co-transported with synaptic vesicles to axonal terminals through binding with vesicle-fusing ATPase NSF1. HDC remaining in soma is degraded by the E3 ubiquitin ligase POE via the proteasome. Aberrant accumulation of histamine in the soma is cytotoxic and causes retinal degeneration. Anchoring of histidine decarboxylase to synaptic vesicles is critical to maintaining neurotransmission and preventing cytotoxic side effects. [ABSTRACT FROM AUTHOR]

The interplay between human microbiota and various physiological systems has garnered significant attention in recent years. The gut microbiota plays a critical role in maintaining physiological homeostasis and influences various aspects of human health, particularly via the gut brain axis. Since 2017, the challenging concept of the gut-retina axis has emerged thanks to a network analysis emphasizing the potential role of the gut microbiota disruption in the development of the age-related macular degeneration and further retinal damages. Many other ocular disorders have been linked to the dysbiosis of the gut microbiota, including uveitis and glaucoma. It has been shown that age related macular degeneration can be prevented or reversed using a diet that induces changes in the gut microbiota. The potential link between the gut microbiota as well as others types of microbiota such as the ocular surface microbiota and the development/progression of age related as well as inherited retinal degenerations and other degenerative eye diseases, has recently been broadened. Therefore, the pathogenesis of several eye diseases has recently been associated with a larger perception called the gut eye axis. This minireview examines the potential mechanisms underlying the gut eye axis and suggests implications for the management of eye diseases. By understanding the modulation of the gut microbiota and its impact on eye disease, this minireview provides insight into potential therapeutic interventions and avenues for future research. [ABSTRACT FROM AUTHOR]

IntroductionMethodsResultsDiscussionBardet-Biedl Syndrome (BBS) is a ciliopathy causing developmental defects and progressive retinal dystrophy, whereas choroidal coloboma is a developmental defect causing structural deficiency in the posterior retina. Both are rarely reported together.Here, we describe the phenotype and genotype of three unrelated patients with co-occurrence of Bardet-Biedl Syndrome and chorioretinal coloboma and review the pertinent literature.We describe three unrelated patients, with variable clinical features of Bardet Biedl syndrome. None had family history of BBS or coloboma. Each carried biallelic variants in BBS1, BBS9 and TTC8 gene, respectively. Two had unilateral chorioretinal coloboma, while one had bilateral chorioretinal coloboma.Although there may be other explanatory factors yet to be revealed, our data suggests that chorioretinal coloboma may be associated with BBS. The Hedgehog (Hh) signaling pathway, an intercellular communicator for development of the eye, is dependent on the primary cilia and plays a crucial role in the closure of the optic fissure. Both disorders therefore involve disruption of primary cilia function which may explain their association. [ABSTRACT FROM AUTHOR]

Background: miR-210 is one of the most evolutionarily conserved microRNAs. It is known to be involved in several physiological and pathological processes, including response to hypoxia, angiogenesis, cardiovascular diseases and cancer. Recently, new roles of this microRNA are emerging in the context of eye and visual system homeostasis. Recent studies in Drosophila melanogaster unveiled that the absence of miR-210 leads to a progressive retinal degeneration characterized by the accumulation of lipid droplets and disruptions in lipid metabolism. However, the possible conservation of miR-210 knock-out effect in the mammalian retina has yet to be explored. Results: We further investigated lipid anabolism and catabolism in miR-210 knock-out (KO) flies, uncovering significant alterations in gene expression within these pathways. Additionally, we characterized the retinal morphology of flies overexpressing (OE) miR-210, which was not affected by the increased levels of the microRNA. For the first time, we also characterized the retinal morphology of miR-210 KO and OE mice. Similar to flies, miR-210 OE did not affect retinal homeostasis, whereas miR-210 KO mice exhibited photoreceptor degeneration. To explore other potential parallels between miR-210 KO models in flies and mice, we examined lipid metabolism, circadian behaviour, and retinal transcriptome in mice, but found no similarities. Specifically, RNA-seq confirmed the lack of involvement of lipid metabolism in the mice's pathological phenotype, revealing that the differentially expressed genes were predominantly associated with chloride channel activity and extracellular matrix homeostasis. Simultaneously, transcriptome analysis of miR-210 KO fly brains indicated that the observed alterations extend beyond the eye and may be linked to neuronal deficiencies in signal detection and transduction. Conclusions: We provide the first morphological characterization of the retina of miR-210 KO and OE mice, investigating the role of this microRNA in mammalian retinal physiology and exploring potential parallels with phenotypes observed in fly models. Although the lack of similarities in lipid metabolism, circadian behaviour, and retinal transcriptome in mice suggests divergent mechanisms of retinal degeneration between the two species, transcriptome analysis of miR-210 KO fly brains indicates the potential existence of a shared upstream mechanism contributing to retinal degeneration in both flies and mammals. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusions Recently, an ‘hyperreflective ganglion cell layer band’ (HGB) has been described on spectral‐domain optical coherence tomography (SD‐OCT) in a subset of patients with retinitis pigmentosa (RP). This study aims to validate and describe the frequency of HGB in a large cohort of Portuguese patients with RP.This single‐centre, cross‐sectional cohort study included consecutive patients with a genetic diagnosis of RP. SD‐OCT images were reviewed to identify the presence of the HGB and other retinal comorbidities. The HGB was defined as a continuous hyperreflective band within the thickness of the ganglion cell layer (GCL). We built mixed‐effects regression models, accounting for inter‐eye correlations, to investigate features predictive of visual acuity. Subsequently, a reduced model was fitted.A total of 398 eyes from 201 patients were included. HGB was identified in 69 (17.3%) eyes from 39 (19.4%) patients. Patients presenting with the HGB were significantly younger at diagnosis and at symptom onset. Median BCVA [ETDRS (IQR)] was 65 (29) letters in eyes with the HGB and 70 (21) letters in eyes without HGB (p < 0.001). In both the full and reduced mixed‐effects models, the presence of HGB and macular hole (MH) was significantly associated with worse BCVA.This study validates the recent description of HGB within the GCL in a subset of patients with RP. Eyes with HGB demonstrated significantly worse BCVA compared to those without HGB, suggesting that the presence of HGB may serve as an SD‐OCT biomarker of worse visual prognosis in these patients. [ABSTRACT FROM AUTHOR]

Transmembrane protein 184b (Tmem184b) has been implicated in axon degeneration and neuromuscular junction dysfunction. Notably, Tmem184b exhibits high expression levels in the retina; however, its specific function within this tissue remains poorly understood. To elucidate the role of Tmem184b in the mammalian visual system, we developed a Tmem184b knockout (KO) model for further investigation. Loss of Tmem184b led to significant decreases in both a and b wave amplitudes of scotopic electroretinogram (ERG) and reduced b wave amplitudes of photopic ERG, respectively, reflecting damage to both the photoreceptors and secondary neuronal cells of the retina. Histologic analyses showed a progressive retinal thinning accompanied by the significantly loss of retinal cells including cone, rod, bipolar, horizontal and retinal ganglion cells. The expression levels of photo‐transduction‐related proteins were down‐regulated in KO retina. TUNEL (terminal deoxynucleotidyl transferase‐mediated biotinylated Uridine‐5'‐triphosphate [UTP] nick end labelling) and glial fibrillary acidic protein (GFAP)‐labelling results suggested the increased cell death and inflammation in the KO mice. RNA‐sequencing analysis and GO enrichment analysis revealed that Tmem184b deletion resulted in down‐regulated genes involved in various biological processes such as visual perception, response to hypoxia, regulation of transmembrane transporter activity. Taken together, our study revealed essential roles of Tmem184b in the mammalian retina and confirmed the underlying mechanisms including cell death, inflammation and hypoxia pathway in the absence of Tmem184b, providing a potential target for therapeutic and diagnostic development. [ABSTRACT FROM AUTHOR]

Whole genome sequencing has been an effective tool in the discovery of variants that cause rare diseases. In this study, we determined the suitability of a novel avidity sequencing approach for rare disease applications. We built a sample to results workflow, combining this sequencing technology with standard library preparation kits, analysis workflows, and interpretation tools. We applied the workflow to ten pedigrees with inherited retinal degeneration (IRD) phenotype. Candidate variants of interest identified through whole genome sequencing were further evaluated using segregation analysis in the additional family members. Potentially causal variants in known IRD genes were detected in five of the ten cases. These high confidence variants were found in ABCA4, CERKL, MAK, PEX6 and RDH12 genes associated with retinal degeneration, that could be sufficient to cause pathology. Pending confirmatory clinical evaluation, we observed a 50% diagnostic yield, consistent with previously reported outcomes of IRD patient analysis. The study confirms that avidity sequencing is effective in detection of causal variants when used for whole genome sequencing in rare disease applications. [ABSTRACT FROM AUTHOR]

Key Clinical Message: The discovery of compound heterozygous NMNAT1 mutations (c.245T>C; p.Val82Ala and c.575A>G; p.Asp192Gly) provides a genetic explanation for Leber congenital amaurosis 9 in an Iranian patient. The proband's symptoms—including severe visual impairment, nystagmus, night blindness, and retinal degeneration—align with Leber congenital amaurosis 9 clinical features. This case underscores the value of exome‐sequencing in diagnosing rare genetic disorders and highlights its role in guiding personalized genetic counseling and potential treatments. Leber congenital amaurosis is a severe early‐onset inherited retinal dystrophy. This study delves into the genetic basis of Leber congenital amaurosis, pinpointing compound heterozygous mutations in the NMNAT1 gene as significant causative factors. While one mutation validates previous findings (c.245T>C; p.Val82Ala), the second (c.575A>G; p.Asp192Gly) proves novel, expanding the genetic landscape of Leber congenital amaurosis 9. Both mutations, inherited independently from nonconsanguineous parents, contribute to the intricate genetic basis of light on Leber congenital amaurosis 9 in this case. The identified mutations shed light on Leber congenital amaurosis genetics in the Iranian population, showcasing the efficacy of exome‐sequencing for molecular diagnoses in hereditary retinal degeneration. These findings provide valuable insights for tailored genetic counseling and potential therapeutic interventions. [ABSTRACT FROM AUTHOR]

Syntaxin 3 is a member of a large protein family of syntaxin proteins that mediate fusion between vesicles and their target membranes. Mutations in the ubiquitously expressed syntaxin 3A splice form give rise to a serious gastrointestinal disorder in humans called microvillus inclusion disorder, while mutations that additionally involve syntaxin 3B, a splice form that is expressed primarily in retinal photoreceptors and bipolar cells, additionally give rise to an early onset severe retinal dystrophy. In this review, we discuss recent studies elucidating the roles of syntaxin 3B and the regulation of syntaxin 3B functionality in membrane fusion and neurotransmitter release in the vertebrate retina. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to answer a key question: is MYO7A-inherited retinal dystrophy (MYO7A-IRD) a photoreceptor-first or retinal pigment epithelium-first disease? A second aim was to determine the most useful biomarkers to monitor disease progression in pediatric patients with Usher syndrome type 1B (USH1) secondary to MYO7A mutation. Methods: Fifty-two eyes from 26 patients with genetically-confirmed MYO7A-IRD underwent swept-source optical coherence tomography (SS-OCT). Structural abnormalities were evaluated and correlated with follow-up time and best corrected visual acuity (BCVA). All patients were evaluated at baseline and after ≥ 40 months of follow-up. Results: The mean (SD) patient age was 9.92 (± 4.1) years. Mean follow-up time was 43 (± 3.2) months. At the final evaluation, the most common qualitative abnormalities in the subfoveal area were alterations in the photoreceptor outer segments (76.9% of eyes) and in the interdigitation zone (IZ) (80.8%). The presence of cystoid macular edema at baseline was independently associated with worse BCVA at the final assessment (increase in LogMAR estimate = 0.142; t(45.00) = 2.78, p = 0.009). The mean width of the ellipsoid and interdigitation zones decreased significantly (by 668 μm and 278 μm, respectively; both p < 0.001). Conclusion: This study shows that disruption of the photoreceptor outer segments and the IZ are the first alterations detected by SS-OCT in the early phases of MYO7A-IRD. These data highlight the potential value of measuring the width of the ellipsoid and IZ to evaluate disease progression. These findings also demonstrate the utility of monitoring for the emergence of cystic lesions as biomarkers of worse visual prognosis in patients with MYO7A-IRD. [ABSTRACT FROM AUTHOR]

'Wet' age-related macular degeneration (AMD) is characterized by pathologic choroidal neovascularization (CNV) that destroys central vision. Abundant evidence points to inflammation and immune cell dysfunction in the progression of CNV in AMD. Mast cells are resident immune cells that control the inflammatory response. Mast cells accumulate and degranulate in the choroid of patients with AMD, suggesting they play a role in CNV. Activated mast cells secrete various biologically active mediators, including inflammatory cytokines and proteolytic enzymes such as tryptase. We investigated the role of mast cells in AMD using a model of CNV. Conditioned media from activated mast cells exerts proangiogenic effects on choroidal endothelial cells and choroidal explants. Laser-induced CNV in vivo was markedly attenuated in mice genetically depleted of mast cells (KitW−sh/W−sh) and in wild-type mice treated with mast cell stabilizer, ketotifen fumarate. Tryptase was found to elicit pronounced choroidal endothelial cell sprouting, migration and tubulogenesis; while tryptase inhibition diminished CNV. Transcriptomic analysis of laser-treated RPE/choroid complex revealed collagen catabolism and extracellular matrix (ECM) reorganization as significant events correlated in clusters of mast cell activation. Consistent with these analyses, compared to wildtype mice choroids of laser-treated mast cell-deficient mice displayed less ECM remodelling evaluated using collagen hybridizing peptide tissue binding. Findings herein provide strong support for mast cells as key players in the progression of pathologic choroidal angiogenesis and as potential therapeutic targets to prevent pathological neovascularization in 'wet' AMD. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is the leading cause of visual impairment in patients age 50 and older, with an estimated 200 million people affected worldwide and a projected 288 million by 2040. This article provides an overview of the epidemiology, risk factors, pathophysiology, clinical manifestations, diagnosis, management, and nursing considerations for AMD to equip nurses with the knowledge to play a crucial role in the early detection of this disease. [ABSTRACT FROM AUTHOR]

Purpose: To explore patterns of disease expression in Alagille syndrome (ALGS). Methods: Patients underwent ophthalmic examination, optical coherence tomography (OCT) imaging, fundus intravenous fluorescein angiography (IVFA), perimetry and full-field electroretinograms (ffERGs). An adult ALGS patient had multimodal imaging and specialized perimetry. Results: The proband (P1) had a heterozygous pathogenic variant in JAG1; (p.Gln410Ter) and was incidentally diagnosed at age 7 with a superficial retinal hemorrhage, vascular tortuosity, and midperipheral pigmentary changes. The hemorrhage recurred 15 months later. Her monozygotic twin sister (P2) had a retinal hemorrhage at the same location at age 11. Visual acuities for both patients were 20/30 in each eye. IVFA was normal. OCT showed thinning of the outer nuclear in the peripapillary retina. A ffERG showed normal cone-mediated responses in P1 (rod-mediated ERGs not documented), normal ffERGs in P2. Coagulation and liver function were normal. An unrelated 42-year-old woman with a de-novo pathogenic variant (p. Gly386Arg) in JAG1 showed a similar pigmentary retinopathy and hepatic vascular anomalies; rod and cone function was normal across large expanses of structurally normal retina that sharply transitioned to a blind atrophic peripheral retina. Conclusion: Nearly identical recurrent intraretinal hemorrhages in monozygotic twins with ALGS suggest a shared subclinical microvascular abnormality. We hypothesize that the presence of large areas of functionally and structurally intact retina surrounded by severe chorioretinal degeneration, is against a predominant involvement of JAG1 in the function of the neurosensory retina, and that instead, primary abnormalities of chorioretinal vascular development and/or homeostasis may drive the peculiar phenotypes. [ABSTRACT FROM AUTHOR]

Purpose: To gain an insight into the pathophysiology of RAB28-associated inherited retinal degeneration through detailed phenotyping and long-term longitudinal follow-up. Methods: The patient underwent complete ophthalmic examinations. Visual function was assessed with microperimetry, full-field electroretinography (ffERG), imaging with optical coherence tomography (OCT), short-wave (SW), and near-infrared (NIR) fundus autofluorescence (FAF). Results: A healthy Haitian woman with homozygous pathogenic variants (c.68C > T; p.Ser23Phe) in RAB28 presented at 16 years of age with a four-year history of blurred vision. Visual acuities were 20/125 in each eye, which remained relatively stable since. At age 27, cone ffERGs were non-detectable and borderline for rod-mediated responses. Kinetic fields were full to a V-4e target, undetectable to a small I-4e stimulus. Microperimetry showed an absolute central scotoma surrounded by a pericentral relative scotoma. SD-OCT showed an undetectable or barely detectable foveal and parafoveal photoreceptor outer nuclear layer (ONL), photoreceptor outer segment (POS), and retinal pigment epithelium (RPE) signals and loss of the SW- and NIR-FAF signals. This atrophic region was separated from a normally laminated retina by a narrow transition zone (TZ) of hyper SW- and NIR-FAF that co-localized with preserved ONL but abnormally thinned POS and RPE. There was minimal centrifugal (<100 $\mu $ μ m) expansion over a six-year period. Conclusion: The cone-rod dystrophy phenotype documented herein supports a critical role of RAB28 for cone function and POS maintenance. Severe central photoreceptor and RPE loss with a predilection for POS loss in TZs suggests possible disruptions of complex mechanisms that maintain central cone photoreceptor and RPE homeostasis. [ABSTRACT FROM AUTHOR]

Biallelic variants in SUMF1 are associated with multiple sulfatase deficiency (MSD), a rare lysosomal storage disorder typically diagnosed in early infancy or childhood, marked by severe neurodegeneration and early mortality. We present clinical and molecular characterisation of three unrelated patients aged 13 to 58 years with milder clinical manifestations due to SUMF1 disease variants, including two adult patients presenting with apparent non‐syndromic retinal dystrophy. Whole genome sequencing identified biallelic SUMF1 variants in all three patients; Patient 1 homozygous for a complex allele c.[290G>T;293T>A]; p.[(Gly97Val);(Val98Glu)], Patient 2 homozygous for c.866A>G; p.(Tyr289Cys), and Patient 3 compound heterozygous for c.726‐1G>C and p.(Tyr289Cys). Electroretinography indicated a rod‐cone dystrophy with additional possible inner retinal dysfunction in all three patients. Biochemical studies confirmed reduced, but not absent, sulfatase enzyme activity in the absence of extra‐ocular disease (Patient 1) or only mild systemic disease (Patients 2, 3). These cases are suggestive that non‐null SUMF1 genotypes can cause an attenuated clinical phenotype, including retinal dystrophy without systemic complications, in adulthood. [ABSTRACT FROM AUTHOR]

Glyburide, a sulfonylurea drug used to treat type 2 diabetes, boasts neuroprotective effects by targeting the sulfonylurea receptor 1 (SUR1) and associated ion channels in various cell types, including those in the central nervous system and the retina. Previously, we demonstrated that glyburide therapy improved retinal function and structure in a rat model of diabetic retinopathy. In the present study, we explore the application of glyburide in non-neovascular ("dry") age-related macular degeneration (AMD), another progressive disease characterized by oxidative stress-induced damage and neuroinflammation that trigger cell death in the retina. We show that glyburide administration to a human cone cell line confers protection against oxidative stress, inflammasome activation, and apoptosis. To corroborate our in vitro results, we also conducted a case-control study, controlling for AMD risk factors and other diabetes medications. It showed that glyburide use in patients reduces the odds of new-onset dry AMD. A positive dose-response relationship is observed from this analysis, in which higher cumulative doses of glyburide further reduce the odds of new-onset dry AMD. In the quest for novel therapies for AMD, glyburide emerges as a promising repurposable drug given its known safety profile. The results from this study provide insights into the multifaceted actions of glyburide and its potential as a neuroprotective agent for retinal diseases; however, further preclinical and clinical studies are needed to validate its therapeutic potential in the context of degenerative retinal disorders such as AMD. [ABSTRACT FROM AUTHOR]