Two patients with Knobloch syndrome due to mutation in COL8A1 gene: case report and review of the literature.

BACKGROUND: Knobloch syndrome (KNO, OMIM # 267,750) is a rare ciliopathy group sydrome characterized by a collagen synthesis disorder. It represents an uncommon cause of pediatric retinal detachment. This report presents two cases with different COL18A1 gene mutations, complicated by retinal detachment. CASE PRESENTATION: Both cases exhibited high myopia and various degrees of occipital skull defect. The first case, a female, had bilateral congenital retinal detachment, posterior embryotoxon, and strabismus. The second case, a male, had unilateral congenital retinal detachment and neuromotor developmental delay. The first case, diagnosed in the early months of life, underwent successful retinal reattachment surgery. However, surgery was not performed on the second case, who presented with late-stage unilateral retinal detachment and pre-phthisis. CONCLUSIONS: The report describes two patients with Knobloch syndrome, one of whom responded favorably to surgery for retinal detachment in both eyes. Successful anatomical results were achieved with early surgical interventions. It is essential to recognize the phenotypic and genetic heterogeneity within KNO.

Statistical Evaluation of ERG Responses: A New Method to Validate Cycle-by-Cycle Recordings in Advanced Retinal Degenerations.

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.

Unveiling Drivers of Retinal Degeneration in RCS Rats: Functional, Morphological, and Molecular Insights.

Retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, significantly contribute to adult blindness. The Royal College of Surgeons (RCS) rat is a well-established disease model for studying these dystrophies; however, molecular investigations remain limited. We conducted a comprehensive analysis of retinal degeneration in RCS rats, including an immunodeficient RCS (iRCS) sub-strain, using ocular coherence tomography, electroretinography, histology, and molecular dissection using transcriptomics and immunofluorescence. No significant differences in retinal degeneration progression were observed between the iRCS and immunocompetent RCS rats, suggesting a minimal role of adaptive immune responses in disease. Transcriptomic alterations were primarily in inflammatory signaling pathways, characterized by the strong upregulation of Tnfa, an inflammatory signaling molecule, and Nox1, a contributor to reactive oxygen species (ROS) generation. Additionally, a notable decrease in Alox15 expression was observed, pointing to a possible reduction in anti-inflammatory and pro-resolving lipid mediators. These findings were corroborated by immunostaining, which demonstrated increased photoreceptor lipid peroxidation (4HNE) and photoreceptor citrullination (CitH3) during retinal degeneration. Our work enhances the understanding of molecular changes associated with retinal degeneration in RCS rats and offers potential therapeutic targets within inflammatory and oxidative stress pathways for confirmatory research and development.

Fluorescence Lifetime Imaging of Human Retinal Pigment Epithelium in Pentosan Polysulfate Toxicity Using Adaptive Optics Scanning Light Ophthalmoscopy.

Purpose: Fluorescence lifetime ophthalmoscopy (FLIO) is an emerging clinical modality that could provide biomarkers of retinal health beyond fluorescence intensity. Adaptive optics (AO) ophthalmoscopy provides the confocality to measure fluorescence lifetime (FL) primarily from the retinal pigment epithelium (RPE) whereas clinical FLIO has greater influence from fluorophores in the inner retina and lens. Adaptive optics fluorescence lifetime ophthalmoscopy (AOFLIO) measures of FL in vivo could provide insight into RPE health at different stages of disease. In this study, we assess changes in pentosan polysulfate sodium (PPS) toxicity, a recently described toxicity that has clinical findings similar to advanced age-related macular degeneration. Methods: AOFLIO was performed on three subjects with PPS toxicity (57-67 years old) and six age-matched controls (50-64 years old). FL was analyzed with a double exponential decay curve fit and with phasor analysis. Regions of interest (ROIs) were subcategorized based on retinal features on optical coherence tomography (OCT) and compared to age-matched controls. Results: Twelve ROIs from PPS toxicity subjects met the threshold for analysis by curve fitting and 15 ROIs met the threshold for phasor analysis. Subjects with PPS toxicity had prolonged FL compared to age-matched controls. ROIs of RPE degeneration had the longest FLs, with individual pixels extending longer than 900 ps. Conclusions: Our study shows evidence that AOFLIO can provide meaningful information in outer retinal disease beyond what is obtainable from fluorescence intensity alone. More studies are needed to determine the prognostic value of AOFLIO.

MIR96 Has Good Potential to Differentiate Human Bone Marrow-Derived Mesenchymal Stem Cells into Photoreceptor-Like Cells.

OBJECTIVES: MicroRNAs play an important role in the development and function of neuron cells. Among these, the miRNA known as MIR96 is abundantly expressed in mammalian retina and significantly affects differentiation, maturation, and survival of human photoreceptor cells. In this study, a mimic to miRNA-96 was transfected into human bone marrowderived mesenchymal stem cells to explore the biological functions of MIR96 at differentiation processing. MATERIALS AND METHODS: A mimic to miRNA-96 and a competitive control were transfected into human bone marrow-derived mesenchymal stem cells using Lipofectamine. After 24 and 48 hours, we evaluated changes in expression levels of genes associated with neural progenitor and photoreceptor differentiation (OTX2, NRL, protein kinase C, SLC1A1, and recoverin) by real-time polymerase chain reaction. In addition, we measured expression of mRNA and protein of the CRX gene (neuroretinal progenitor cell marker) and the RHO gene (terminal differentiation marker) using real-time polymerase chain reaction and immunocytochemistry, respectively. RESULTS: Real-time polymerase chain reaction results showed increased levels of RHO and recoverin mRNA after 24 hours in transfected cells. In addition, mRNA levels of OTX2, CRX, NRL, RHO, recoverin, and protein kinase C increased after 48 hours in transfected cells. Immunocytochemistry results confirmed these findings by demonstrating RHO and CRX at both 24 and 48 hours in transfected cells. CONCLUSIONS: Control of the expression of MIR96 can be a good strategy to promote cell differentiation and can be used in cell therapy for retinal degeneration. Our results showed that human bone marrow-derived mesenchymal stem cells can differentiate into photoreceptor cells after transfection with MIR96. These results support therapeutic use of MIR96 in retinal degeneration and suggest human bone marrowderived mesenchymal stem cells as a promising tool for interventions.

Simultaneous Pigmented Paravenous Retinochoroidal Atrophy and Retinitis Pigmentosa in the Contralateral Eye.

This case report describes a simultaneous diagnosis of paravenous retinochoroidal atrophy and retinitis pigmentosa in the same patient.

FOVEAL PHENOTYPES IN CHOROIDEREMIA ON ADAPTIVE OPTICS SCANNING LIGHT OPHTHALMOSCOPY.

PURPOSE: Choroideremia is an X-linked inherited retinal degeneration involving the choriocapillaris, retinal pigment epithelium, and photoreceptors. Adaptive optics scanning light ophthalmoscopy allows visualization of retinal structure at the level of individual cells and is well poised to provide insight into the pathophysiologic mechanisms underpinning the retinal degeneration in choroideremia. METHODS: Foveal adaptive optics scanning light ophthalmoscopy images of 102 eyes of 54 individuals with choroideremia were analyzed. Measures were compared with those from standard clinical imaging. Visual acuity was also measured and compared with quantitative foveal metrics. RESULTS: The 3 distinct phenotypes observed were: relatively normal (5 eyes, 4 individuals), spiderweb (9 eyes, 7 individuals), and salt and pepper (87 eyes, 47 individuals). Peak cone density (86 eyes of 51 individuals) was significantly lower in choroideremia than in healthy retinas (P < 0.0001, range: 29,382-157,717 cones/mm2). Peak cone density was significantly related to extent of retained ellipsoid zone on en face optical coherence tomography (r2 = 0.47, P = 0.0009) and inversely related to visual acuity (r2 = 0.20, P = 0.001). CONCLUSION: Distinct phenotypes can be observed on adaptive optics scanning light ophthalmoscopy imaging in choroideremia that cannot always be discerned on standard clinical imaging. Quantitative measures on adaptive optics imaging are related to the structural and functional severity of disease.

Eye Drop with Fas-Blocking Peptide Attenuates Age-Related Macular Degeneration.

Age-related macular degeneration (AMD), characterized by macular retinal degeneration, poses a significant health concern due to the lack of effective treatments for prevalent dry AMD. The progression of AMD is closely linked to reactive oxygen species and Fas signaling, emphasizing the need for targeted interventions. In this study, we utilized a NaIO3-induced retinal degeneration mouse model to assess the efficacy of Fas-blocking peptide (FBP). Intravitreal administration of FBP successfully suppressed Fas-mediated inflammation and apoptosis, effectively arresting AMD progression in mice. We developed a 6R-conjugated FBP (6R-FBP) for eye drop administration. 6R-FBP, administered as an eye drop, reached the retinal region, attenuating degeneration by modulating the expression of inflammatory cytokines and blocking Fas-mediated apoptosis in rodent and rabbit NaIO3-induced retinal degeneration models to address practical concerns. Intravitreal FBP and 6R-FBP eye drops effectively reduced retinal degeneration and improved retinal thickness in rodent and rabbit models. This study highlights the therapeutic potential of FBP, particularly 6R-FBP as an eye drop, in inhibiting Fas-mediated cell signaling and protecting against retinal cell death and inflammation in dry AMD. Future investigations should explore the translational prospects of this approach in primates with eye structures comparable to those of humans.

Halofuginone prevents outer retinal degeneration in a mouse model of light-induced retinopathy.

Photoreceptor cell death can cause progressive and irreversible visual impairments. Still, effective therapies on retinal neuroprotection are not available. Hypoxia-inducible factors (HIFs) are transcriptional factors which strongly regulate angiogenesis, erythropoiesis, intracellular metabolism, and programed cell death under a hypoxic or an abnormal metabolic oxidative stress condition. Therefore, we aimed to unravel that inhibition of HIFs could prevent disease progression in photoreceptor cell death, as recent studies showed that HIFs might be pathologic factors in retinal diseases. Adult male balb/cAJcl (8 weeks old; BALB/c) were used to investigate preventive effects of a novel HIF inhibitor halofuginone (HF) on a murine model of light-induced retinopathy. After intraperitoneal injections of phosphate-buffered saline (PBS) or HF (0.4 mg/kg in PBS) for 5 days, male BALB/c mice were subjected to a dark-adaption to being exposed to a white LED light source at an intensity of 3,000 lux for 1 hour in order to induce light-induced retinal damage. After extensive light exposure, retinal damage was evaluated using electroretinography (ERG), optical coherence tomography (OCT), and TUNEL assay. Light-induced retinal dysfunction was suppressed by HF administration. The amplitudes of scotopic a-wave and b-wave as well as that of photopic b-wave were preserved in the HF-administered retina. Outer retinal thinning after extensive light exposure was suppressed by HF administration. Based on the TUNEL assay, cell death in the outer retina was seen after light exposure. However, its cell death was not detected in the HF-administered retina. Halofuginone was found to exert preventive effects on light-induced outer retinal cell death.

Integrative Kinase Activity Profiling and Phosphoproteomics of rd10 Mouse Retina during cGMP-Dependent Retinal Degeneration.

Inherited retinal degenerative diseases (IRDs) are a group of rare diseases that lead to a progressive loss of photoreceptor cells and, ultimately, blindness. The overactivation of cGMP-dependent protein kinase G (PKG), one of the key effectors of cGMP-signaling, was previously found to be involved in photoreceptor cell death and was studied in murine IRD models to elucidate the pathophysiology of retinal degeneration. However, PKG is a serine/threonine kinase (STK) with several hundred potential phosphorylation targets and, so far, little is known about the specificity of the target interaction and downstream effects of PKG activation. Here, we carried out both the kinome activity and phosphoproteomic profiling of organotypic retinal explant cultures derived from the rd10 mouse model for IRD. After treating the explants with the PKG inhibitor CN03, an overall decrease in peptide phosphorylation was observed, with the most significant decrease occurring in seven peptides, including those from the known PKG substrate cyclic-AMP-response-element-binding CREB, but also Ca2+/calmodulin-dependent kinase (CaMK) peptides and TOP2A. The phosphoproteomic data, in turn, revealed proteins with decreased phosphorylation, as well as proteins with increased phosphorylation. The integration of both datasets identified common biological networks altered by PKG inhibition, which included kinases predominantly from the so-called AGC and CaMK families of kinases (e.g., PKG1, PKG2, PKA, CaMKs, RSKs, and AKTs). A pathway analysis confirmed the role of CREB, Calmodulin, mitogen-activated protein kinase (MAPK) and CREB modulation. Among the peptides and pathways that showed reduced phosphorylation activity, the substrates CREB, CaMK2, and CaMK4 were validated for their retinal localization and activity, using immunostaining and immunoblotting in the rd10 retina. In summary, the integrative analysis of the kinome activity and phosphoproteomic data revealed both known and novel PKG substrates in a murine IRD model. This data establishes a basis for an improved understanding of the biological pathways involved in cGMP-mediated photoreceptor degeneration. Moreover, validated PKG targets like CREB and CaMKs merit exploration as novel (surrogate) biomarkers to determine the effects of a clinical PKG-targeted treatment for IRDs.

Transplanted human photoreceptors transfer cytoplasmic material but not to the recipient mouse retina.

BACKGROUND: The discovery of material transfer between transplanted and host mouse photoreceptors has expanded the possibilities for utilizing transplanted photoreceptors as potential vehicles for delivering therapeutic cargo. However, previous research has not directly explored the capacity for human photoreceptors to engage in material transfer, as human photoreceptor transplantation has primarily been investigated in rodent models of late-stage retinal disease, which lack host photoreceptors. METHODS: In this study, we transplanted human stem-cell derived photoreceptors purified from human retinal organoids at different ontological ages (weeks 10, 14, or 20) into mouse models with intact photoreceptors and assessed transfer of human proteins and organelles to mouse photoreceptors. RESULTS: Unexpectedly, regardless of donor age or mouse recipient background, human photoreceptors did not transfer material in the mouse retina, though a rare subset of donor cells (< 5%) integrated into the mouse photoreceptor cell layer. To investigate the possibility that a species barrier impeded transfer, we used a flow cytometric assay to examine material transfer in vitro. Interestingly, dissociated human photoreceptors transferred fluorescent protein with each other in vitro, yet no transfer was detected in co-cultures of human and mouse photoreceptors, suggesting that material transfer is species specific. CONCLUSIONS: While xenograft models are not a tractable system to study material transfer of human photoreceptors, these findings demonstrate that human retinal organoid-derived photoreceptors are competent donors for material transfer and thus may be useful to treat retinal degenerative disease.

Compounding engineered mesenchymal stem cell-derived exosomes: A potential rescue strategy for retinal degeneration.

The prevalence of retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, has been increasing globally and is linked to the aging population and improved life expectancy. These diseases are characterized by chronic, progressive neuronal damage or depletion of the photoreceptor cells in the retina, and limited effective treatment options are currently available. Mesenchymal stem cell-derived exosomes (MSC-EXOs) containing cytokines, growth factors, lipids, mRNA, and miRNA, which act as mediators of intercellular communication transferring bioactive molecules to recipient cells, offer an appealing, non-cellular nanotherapeutic approach for retinal degenerative diseases. However, treatment specificity is compromised due to their high heterogeneity in size, content, functional effects, and parental cellular source. To improve this, engineered MSC-EXOs with increased drug-loading capacity, targeting ability, and resistance to bodily degradation and elimination have been developed. This review summarizes the recent advances in miRNAs of MSC-EXOs as a treatment for retinal degeneration, discussing the strategies and methods for engineering therapeutic MSC-EXOs. Notably, to address the single functional role of engineered MSC-EXOs, we propose a novel concept called "Compound Engineered MSC-EXOs (Co-E-MSC-EXOs)" along with its derived potential therapeutic approaches. The advantages and challenges of employing Co-E-MSC-EXOs for retinal degeneration in clinical applications, as well as the strategies and issues related to them, are also highlighted.

Voluntary exercise preserves visual function and reduces inflammatory response in an adult mouse model of autosomal dominant retinitis pigmentosa.

Whole-body physical exercise has been shown to promote retinal structure and function preservation in animal models of retinal degeneration. It is currently unknown how exercise modulates retinal inflammatory responses. In this study, we investigated cytokine alterations associated with retinal neuroprotection induced by voluntary running wheel exercise in a retinal degeneration mouse model of class B1 autosomal dominant retinitis pigmentosa, I307N Rho. I307N Rho mice undergo rod photoreceptor degeneration when exposed to bright light (induced). Our data show, active induced mice exhibited significant preservation of retinal and visual function compared to inactive induced mice after 4 weeks of exercise. Retinal cytokine expression revealed significant reductions of proinflammatory chemokines, keratinocyte-derived chemokine (KC) and interferon gamma inducible protein-10 (IP-10) expression in active groups compared to inactive groups. Through immunofluorescence, we found KC and IP-10 labeling localized to retinal vasculature marker, collagen IV. These data show that whole-body exercise lowers specific retinal cytokine expression associated with retinal vasculature. Future studies should determine whether suppression of inflammatory responses is requisite for exercise-induced retinal protection.

Intrinsic signal optoretinography of dark adaptation abnormality due to rod photoreceptor degeneration.

This research aims to investigate the potential of using intrinsic optical signal (IOS) optoretinography (ORG) to objectively detect dark adaptation (DA) abnormalities related to rod photoreceptor degeneration. Functional optical coherence tomography (OCT) was employed in both wild-type (WT) and retinal degeneration 10 (rd10) mice to conduct this assessment. Dynamic OCT measurements captured the changes in retinal thickness and reflectance from light-to-dark transition. Comparative analysis revealed significant IOS alterations within the outer retina. Specifically, a reduction in thickness from external limiting membrane (ELM) peak to retinal pigment epithelium (RPE) peak was observed (WT: 1.13 ± 0.69 µm, 30 min DA; rd10: 2.64 ± 0.86 µm, 30 min DA), as well as a decrease in the intensity of the inner segment ellipsoid zone (EZ) in 30 min DA compared to light adaptation (LA). The reduction of relative EZ intensity was notable in rd10 after 5 min DA and in WT after 15 min DA, with a distinguishable difference between rd10 and WT after 10 min DA. Furthermore, our findings indicated a significant decrease in the relative intensity of the hypo-reflective band between EZ and RPE in rd10 retinas during DA, which primarily corresponds to the outer segment (OS) region. In conclusion, the observed DA-IOS abnormalities, including changes in ELM-RPE thickness, EZ, and OS intensity, hold promise as differentiators between WT and rd10 mice before noticeable morphological abnormalities occur. These findings suggest the potential of this non-invasive imaging technique for the early detection of dysfunction in retinal photoreceptors.

Macrophages coordinate immune response to laser-induced injury via extracellular traps.

BACKGROUND: Retinal degeneration results from disruptions in retinal homeostasis due to injury, disease, or aging and triggers peripheral leukocyte infiltration. Effective immune responses rely on coordinated actions of resident microglia and recruited macrophages, critical for tissue remodeling and repair. However, these phagocytes also contribute to chronic inflammation in degenerated retinas, yet the precise coordination of immune response to retinal damage remains elusive. Recent investigations have demonstrated that phagocytic cells can produce extracellular traps (ETs), which are a source of self-antigens that alter the immune response, which can potentially lead to tissue injury. METHODS: Innovations in experimental systems facilitate real-time exploration of immune cell interactions and dynamic responses. We integrated in vivo imaging with ultrastructural analysis, transcriptomics, pharmacological treatments, and knockout mice to elucidate the role of phagocytes and their modulation of the local inflammatory response through extracellular traps (ETs). Deciphering these mechanisms is essential for developing novel and enhanced immunotherapeutic approaches that can redirect a specific maladaptive immune response towards favorable wound healing in the retina. RESULTS: Our findings underscore the pivotal role of innate immune cells, especially macrophages/monocytes, in regulating retinal repair and inflammation. The absence of neutrophil and macrophage infiltration aids parenchymal integrity restoration, while their depletion, particularly macrophages/monocytes, impedes vascular recovery. We demonstrate that macrophages/monocytes, when recruited in the retina, release chromatin and granular proteins, forming ETs. Furthermore, the pharmacological inhibition of ETosis support retinal and vascular repair, surpassing the effects of blocking innate immune cell recruitment. Simultaneously, the absence of ETosis reshapes the inflammatory response, causing neutrophils, helper, and cytotoxic T-cells to be restricted primarily in the superficial capillary plexus instead of reaching the damaged photoreceptor layer. CONCLUSIONS: Our data offer novel insights into innate immunity's role in responding to retinal damage and potentially help developing innovative immunotherapeutic approaches that can shift the immune response from maladaptive to beneficial for retinal regeneration.

A genetic screen to uncover mechanisms underlying lipid transfer protein function at membrane contact sites.

Lipid transfer proteins mediate the transfer of lipids between organelle membranes, and the loss of function of these proteins has been linked to neurodegeneration. However, the mechanism by which loss of lipid transfer activity leads to neurodegeneration is not understood. In Drosophila photoreceptors, depletion of retinal degeneration B (RDGB), a phosphatidylinositol transfer protein, leads to defective phototransduction and retinal degeneration, but the mechanism by which loss of this activity leads to retinal degeneration is not understood. RDGB is localized to membrane contact sites through the interaction of its FFAT motif with the ER integral protein VAP. To identify regulators of RDGB function in vivo, we depleted more than 300 VAP-interacting proteins and identified a set of 52 suppressors of rdgB The molecular identity of these suppressors indicates a role of novel lipids in regulating RDGB function and of transcriptional and ubiquitination processes in mediating retinal degeneration in rdgB9 The human homologs of several of these molecules have been implicated in neurodevelopmental diseases underscoring the importance of VAP-mediated processes in these disorders.

Cohen syndrome combined with psychiatric symptoms: a case report.

BACKGROUND: Cohen syndrome (CS) is a rare autosomal recessive inherited condition characterized by pathological changes affecting multiple systems. The extensive clinical variability associated with CS poses a significant diagnostic challenge. Additionally, there is limited documentation on the co-occurrence of CS with psychiatric symptoms. CASE REPORT: We report a case of a 30-year-old patient exhibiting characteristic physical features and psychiatric symptoms. Whole exome sequencing identified two heterozygous variants, a nonsense variation c.4336 C > T and a missense mutation c.4729G > A. Integrating clinical manifestations with genetic test results, we established the diagnosis of CS combined with psychiatric symptoms. CONCLUSIONS: This case introduces a novel missense variant as a candidate in the expanding array of VPS13B pathogenic variants. Its clinical significance remains unknown, and further investigation may broaden the spectrum of pathogenic variants associated with the VPS13B gene. Early diagnosis of CS is crucial for the prognosis of young children and holds significant importance for their families.

[Features of genetic mutations in children with high myopia combined with peripheral retinal degenerations]. / Osobennosti mutatsii v genakh u detei s vysokoi blizorukost'yu, sochetayushcheisya s perifericheskimi vitreokhorioretinal'nymi distrofiyami.

Degenerative changes in the peripheral regions of the ocular fundus allow a closer look at both the role of collagen genes and their mutations in children with high myopia. PURPOSE: The study investigates the features of genetic mutations in children with high myopia combined with peripheral retinal degenerations. MATERIAL AND METHODS: Study group was formed from the database of genetic studies of the Scientific and Clinical Center OOO Oftalmic, which consists of 4362 patients referred for medical genetic counseling and molecular genetic testing from 2016 to 2021. Selection criteria were: male and female patients, aged 5-18 years old, who had the following clinical signs: high myopia (>6.00 D) and the presence of peripheral retinal degenerations (PRD). The study considered both isolated cases of ophthalmic pathology, as well as its syndromic forms. The final selection included 40 children. All patients had consulted with a geneticist. Whole-exome sequencing (WES), next generation sequencing (NGS), and single gene sequencing were conducted by taking 5 mL of peripheral venous blood and extracting deoxyribonucleic acid (DNA). RESULTS: In patients with isolated cases of ophthalmic pathology (peripheral retinal degenerations and high myopia) with a confirmed genetic diagnosis, mutations in the COL2A1 gene were detected in 77.4% of cases, and in the COL11A1 gene - in 22.6% of cases. In Stickler syndrome with a confirmed genetic diagnosis, mutations in the COL2A1 gene were detected in 33.3% of cases. In Marshall syndrome, the mutation in the COL11A1 gene was detected in 11.1% of cases. In children with Ehlers-Danlos, Knobloch type 1, Cohen, Marfan, Wagner syndromes mutations in the genes COL5A1, COL18A1, VPS13B, FBN1, VCAN were detected in 55.6% of cases. In 33.3% of cases of Knobloch type 1, Cohen, Wagner syndromes the mutation is found in both copies of the gene (i.e., in both chromosomes), which leads to the development of peripheral retinal degenerations with high myopia. CONCLUSION: The results of the conducted molecular genetic testing expand our understanding of the mutation spectrum in the genes of children with both isolated cases of ophthalmic pathology, as well as syndromic pathology.

Retinal Ciliopathies and Potential Gene Therapies: A Focus on Human iPSC-Derived Organoid Models.

The human photoreceptor function is dependent on a highly specialised cilium. Perturbation of cilial function can often lead to death of the photoreceptor and loss of vision. Retinal ciliopathies are a genetically diverse range of inherited retinal disorders affecting aspects of the photoreceptor cilium. Despite advances in the understanding of retinal ciliopathies utilising animal disease models, they can often lack the ability to accurately mimic the observed patient phenotype, possibly due to structural and functional deviations from the human retina. Human-induced pluripotent stem cells (hiPSCs) can be utilised to generate an alternative disease model, the 3D retinal organoid, which contains all major retinal cell types including photoreceptors complete with cilial structures. These retinal organoids facilitate the study of disease mechanisms and potential therapies in a human-derived system. Three-dimensional retinal organoids are still a developing technology, and despite impressive progress, several limitations remain. This review will discuss the state of hiPSC-derived retinal organoid technology for accurately modelling prominent retinal ciliopathies related to genes, including RPGR, CEP290, MYO7A, and USH2A. Additionally, we will discuss the development of novel gene therapy approaches targeting retinal ciliopathies, including the delivery of large genes and gene-editing techniques.

New Perspectives in Stem Cell Transplantation and Associated Therapies to Treat Retinal Diseases: From Gene Editing to 3D Bioprinting.

Inherited and non-inherited retinopathies can affect distinct cell types, leading to progressive cell death and visual loss. In the last years, new approaches have indicated exciting opportunities to treat retinopathies. Cell therapy in retinitis pigmentosa, age-related macular disease, and glaucoma have yielded encouraging results in rodents and humans. The first two diseases mainly impact the photoreceptors and the retinal pigmented epithelium, while glaucoma primarily affects the ganglion cell layer. Induced pluripotent stem cells and multipotent stem cells can be differentiated in vitro to obtain specific cell types for use in transplant as well as to assess the impact of candidate molecules aimed at treating retinal degeneration. Moreover, stem cell therapy is presented in combination with newly developed methods, such as gene editing, Müller cells dedifferentiation, sheet & drug delivery, virus-like particles, optogenetics, and 3D bioprinting. This review describes the recent advances in this field, by presenting an updated panel based on cell transplants and related therapies to treat retinopathies.