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Translational Vision Science &... Nov 2023This systematic review evaluates the safety and efficacy of ocular gene therapy using adeno-associated virus (AAV). (Meta-Analysis)
Meta-Analysis
PURPOSE
This systematic review evaluates the safety and efficacy of ocular gene therapy using adeno-associated virus (AAV).
METHODS
MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov were searched systematically for controlled or non-controlled interventional gene therapy studies using key words related to retinal diseases, gene therapy, and AAV vectors. The primary outcome measure was safety, based on ocular severe adverse events (SAEs). Secondary outcome measures evaluated efficacy of the therapy based on best corrected visual acuity (BCVA) and improvements in visual sensitivity and systemic involvement following ocular delivery. Pooling was done using a DerSimonian Laird random effects model. Risk of bias was assessed using the Cochrane Risk of Bias Tool, version 1.
RESULTS
Our search identified 3548 records. Of these, 80 publications met eligibility criteria, representing 28 registered clinical trials and 5 postmarket surveillance studies involving AAV gene therapy for Leber congenital amaurosis (LCA), choroideremia, Leber hereditary optic neuropathy (LHON), age-related macular degeneration (AMD), retinitis pigmentosa (RP), X-linked retinoschisis, and achromatopsia. Overall, AAV therapy vectors were associated with a cumulative incidence of at least one SAE of 8% (95% confidence intervals [CIs] of 5% to 12%). SAEs were often associated with the surgical procedure rather than the therapeutic vector itself. Poor or inconsistent reporting of adverse events (AEs) were a limitation for the meta-analysis. The proportion of patients with any improvement in BCVA and visual sensitivity was 41% (95% CIs of 31% to 51%) and 51% (95% CIs of 31% to 70%), respectively. Systemic immune involvement was associated with a cumulative incidence of 31% (95% CI = 21% to 42%).
CONCLUSIONS
AAV gene therapy vectors appear to be safe but the surgical procedure required to deliver them is associated with some risk. The large variability in efficacy can be attributed to the small number of patients treated, the heterogeneity of the population and the variability in dosage, volume, and follow-up.
TRANSLATIONAL RELEVANCE
This systematic review will help to inform and guide future clinical trials.
Topics: Humans; Retinal Degeneration; Dependovirus; Macular Degeneration; Retinitis Pigmentosa; Genetic Therapy
PubMed: 37982768
DOI: 10.1167/tvst.12.11.24 -
Stem Cells Translational Medicine Jan 2024Cone cell death is a characteristic shared by various retinal degenerative disorders, such as cone-rod dystrophy, Stargardt disease, achromatopsia, and retinitis...
Cone cell death is a characteristic shared by various retinal degenerative disorders, such as cone-rod dystrophy, Stargardt disease, achromatopsia, and retinitis pigmentosa. This leads to conditions like color blindness and permanently impaired visual acuity. Stem cell therapy focused on photoreceptor replacement holds promise for addressing these conditions. However, identifying surface markers that aid in enriching retinal progenitor cells (RPCs) capable of differentiating into cones remains a complex task. In this study, we employed single-cell RNA sequencing to scrutinize the transcriptome of developing retinas in C57BL/6J mice. This revealed the distinctive expression of somatostatin receptor 2 (Sstr2), a surface protein, in late-stage RPCs exhibiting the potential for photoreceptor differentiation. In vivo lineage tracing experiments verified that Sstr2+ cells within the late embryonic retina gave rise to cones, amacrine and horizontal cells during the developmental process. Furthermore, Sstr2+ cells that were isolated from the late embryonic mouse retina displayed RPC markers and exhibited the capability to differentiate into cones in vitro. Upon subretinal transplantation into both wild-type and retinal degeneration 10 (rd10) mice, Sstr2+ cells survived and expressed cone-specific markers. This study underscores the ability of Sstr2 to enrich late-stage RPCs primed for cone differentiation to a large extent. It proposes the utility of Sstr2 as a biomarker for RPCs capable of generating cones for transplantation purposes.
Topics: Animals; Mice; Mice, Inbred C57BL; Receptors, Somatostatin; Retina; Retinal Cone Photoreceptor Cells; Retinal Degeneration; Stem Cells
PubMed: 37935630
DOI: 10.1093/stcltm/szad073 -
European Journal of Ophthalmology Nov 2023Achromatopsia is an autosomal recessive cone dysfunction syndrome, characterized by absence of color discrimination, low visual acuity, photophobia, and nystagmus....
BACKGROUND
Achromatopsia is an autosomal recessive cone dysfunction syndrome, characterized by absence of color discrimination, low visual acuity, photophobia, and nystagmus. Achromatopsia constitutes a common cause of visual impairment in children, with a prevalence of 1:30,000 worldwide.
OBJECTIVE
To characterize the clinical characteristics of achromatopsia, the main genes causing the disease in our population and the clinical course of the disease, with an emphasis on visual function stability with increasing age.
METHODS
Retrospective study based on medical charts of patients with achromatopsia. Patients were divided into two groups according to their age at last follow-up: older and younger than 10 years. A subset of patients with long term follow-up were analyzed separately, with patients being described in both age groups.
RESULTS
Seventy-six patients were included in the study. The mean age was 14.28 years. Variants in the CNGA3 gene were the most common (73.6%). Clinical characteristics included photophobia (96.2%), nystagmus (93.6%), hypermetropia (72.3%) and strabismus (51.1%). In the large cohort there was no correlation of age with visual acuity ( = 0.129). In the separate subset cohort with long follow-up there was a relative improvement in visual acuity with age ( < 0.001).
CONCLUSIONS
CNGA3 is the main gene associated with achromatopsia in our population (around ∼ 73%), which is in contrast to the distribution worldwide (∼ 25%). Most achromats suffer from photophobia and nystagmus, and the main refractive error is hypermetropia. Achromatopsia's natural course seems to be stationary, and there may even be a slight improvement in visual acuity with time.
PubMed: 37920903
DOI: 10.1177/11206721231212768 -
International Journal of Molecular... Oct 2023This study aimed to investigate the prevalence of color vision deficiencies (CVDs) and determine whether carriers could be detected by analyzing the visual pigment...
This study aimed to investigate the prevalence of color vision deficiencies (CVDs) and determine whether carriers could be detected by analyzing the visual pigment genes. Materials and Methods: The data of students who underwent routine CVD screening using the Ishihara color test in Kaohsiung, Southern Taiwan were analyzed. Furthermore, the DNA samples of 80 randomly selected females and four obligate carriers were analyzed. The most upstream genes, downstream genes, and the most downstream genes in the red/green pigment gene arrays were amplified separately using polymerase chain reaction (PCR), and exon 5 of each gene was analyzed. The prevalence of congenital red-green CVD in this study was 3.46% in males and 0.14% in females. The PCR analysis of the first gene, downstream gene, and last gene revealed normal patterns in 73 normal cases. Seven unusual patterns were detected in two proton carriers and five deutan carriers. Among the randomly selected females, 8.8% (7/80) were CVD carriers. The prevalence of CVD among male Taiwanese students in this study was 3.46%. Female carriers of congenital CVD can be identified by molecular analysis of the visual pigment genes. The proportion of CVD carriers among the randomly selected females was 8.8%, which was slightly higher than expected and further studies are warranted.
Topics: Humans; Male; Female; Color Vision Defects; Color Perception; Retinal Pigments; Prevalence; Taiwan; Cardiovascular Diseases
PubMed: 37894926
DOI: 10.3390/ijms242015247 -
Indian Journal of Ophthalmology Nov 2023This study aimed to evaluate color perception (CP) changes on Ishihara plates following red-tinted contact lenses in subjects with low vision (LV) from retinal diseases. (Observational Study)
Observational Study
PURPOSE
This study aimed to evaluate color perception (CP) changes on Ishihara plates following red-tinted contact lenses in subjects with low vision (LV) from retinal diseases.
METHODS
A cross-sectional observational study without control involved 84 subjects, aged 20-70 years, having LV from retinal diseases to examine CP changes following wearing red-tinted contact lenses. The subjects viewed Ishihara plates, with each eye separately, before and after wearing red lenses in two categories: "plates 1-21" and "plates 22-25". Change in CP with the use of a red lens was the primary outcome measure.
RESULTS
There was a significant increase in the number of plates read in both categories, that is, plates 1-21 (P = 0.002) and plates 22-25 (P = 0.032), the latter being used to diagnose the red-green defects. Although 70 eyes could read both digits on plates 22-25 and appeared to have normal color vision (CV) at baseline, this number rose to 99 eyes following the use of red-tinted lenses. There was a significant change in the type of CP (red defect/green defect/normal/undefined defect) (P = 0.022) with the application of a red-tinted lens.
CONCLUSIONS
The use of red-tinted lenses caused a significant increase in the number of plates read, increased the number of subjects who appeared normal on plates 22-25, and significantly changed CP of LV subjects. These lenses can be a valuable aid for LV subjects. Although Ishihara plates can diagnose only red-green defects, further studies on CV testing techniques that detect both red-green and blue-yellow CV defects are recommended.
Topics: Humans; Color Perception; Vision, Low; Cross-Sectional Studies; Vision Tests; Color Vision Defects; Retinal Diseases; Color Vision
PubMed: 37870020
DOI: 10.4103/IJO.IJO_2532_22 -
Investigative Ophthalmology & Visual... Oct 2023Achromatopsia is a rare inherited disorder rendering retinal cone photoreceptors nonfunctional. As a consequence, the sizable foveal representation in the visual cortex...
PURPOSE
Achromatopsia is a rare inherited disorder rendering retinal cone photoreceptors nonfunctional. As a consequence, the sizable foveal representation in the visual cortex is congenitally deprived of visual input, which prompts a fundamental question: is the cortical representation of the central visual field in patients with achromatopsia remapped to take up processing of paracentral inputs? Such remapping might interfere with gene therapeutic treatments aimed at restoring cone function.
METHODS
We conducted a multicenter study to explore the nature and plasticity of vision in the absence of functional cones in a cohort of 17 individuals affected by autosomal recessive achromatopsia and confirmed biallelic disease-causing CNGA3 or CNGB3 mutations. Specifically, we tested the hypothesis of foveal remapping in human achromatopsia. For this purpose, we applied two independent functional magnetic resonance imaging (fMRI)-based mapping approaches, i.e. conventional phase-encoded eccentricity and population receptive field mapping, to separate data sets.
RESULTS
Both fMRI approaches produced the same result in the group comparison of achromatopsia versus healthy controls: sizable remapping of the representation of the central visual field in the primary visual cortex was not apparent.
CONCLUSIONS
Remapping of the cortical representation of the central visual field is not a general feature in achromatopsia. It is concluded that plasticity of the human primary visual cortex is less pronounced than previously assumed. A pretherapeutic imaging workup is proposed to optimize interventions.
Topics: Humans; Color Vision Defects; Retinal Cone Photoreceptor Cells; Cyclic Nucleotide-Gated Cation Channels; Mutation; Visual Cortex
PubMed: 37847226
DOI: 10.1167/iovs.64.13.23 -
BMC Ophthalmology Sep 2023Posterior scleritis is an inflammatory reaction of the sclera that occurs posterior to the ora serrata. The aim of this study was to present a case of posterior...
BACKGROUND
Posterior scleritis is an inflammatory reaction of the sclera that occurs posterior to the ora serrata. The aim of this study was to present a case of posterior scleritis and to analyze choroidal circulatory and structural changes using laser speckle flowgraphy (LSFG) and optical coherence tomography (OCT), respectively.
CASE PRESENTATION
A 64-year-old man presented to our department because of hyperemia of the left eye for one week, diplopia, ocular pain, and distorted vision when looking leftward. At an initial examination, his best-corrected visual acuity was 1.0 Oculi uterque (OU), with mild conjunctival hyperemia oculus dexter (OD) and marked ciliary hyperemia oculus sinister (OS). Color fundus photographs revealed a cluster of choroidal folds extending from the macula to the inferior retinal region OS. Swept-Source OCT showed choroidal thickening OD, and bacillary layer detachment and paracentral middle maculopathy on the paracentral side of the optic nerve papilla, suggesting severe inflammation. Fluorescein angiography showed hyperfluorescence in the optic disc and window defects around the macula OU. Indocyanine green angiography showed mottled choroidal vascular hyperpermeability findings in the late stage. B-mode echography displayed thickening of the posterior wall of the left eye. Orbital magnetic resonance imaging showed the thickened posterior eyeball. The patient was diagnosed with posterior scleritis, and 30 mg of oral prednisolone was then given and tapered off over the next 4 months. The hyperemia and intraocular inflammation resolved after the treatment. The rate of change in macular blood flow assessed by the mean blur rate on LSFG was 20.5% and 20.2% decrease OD and OS, respectively, before and after treatment. The central choroidal thickness showed 8.8% and 37.8% decrease OD and OS, respectively.
CONCLUSION
Posterior scleritis complicated with choroiditis was suggested to show different choroidal circulatory dynamics from those in other choroidal inflammations.
Topics: Male; Humans; Middle Aged; Scleritis; Hyperemia; Choroid; Inflammation; Retina
PubMed: 37726746
DOI: 10.1186/s12886-023-03140-8 -
Signal Transduction and Targeted Therapy Sep 2023The endoplasmic reticulum (ER) functions as a quality-control organelle for protein homeostasis, or "proteostasis". The protein quality control systems involve... (Review)
Review
The endoplasmic reticulum (ER) functions as a quality-control organelle for protein homeostasis, or "proteostasis". The protein quality control systems involve ER-associated degradation, protein chaperons, and autophagy. ER stress is activated when proteostasis is broken with an accumulation of misfolded and unfolded proteins in the ER. ER stress activates an adaptive unfolded protein response to restore proteostasis by initiating protein kinase R-like ER kinase, activating transcription factor 6, and inositol requiring enzyme 1. ER stress is multifaceted, and acts on aspects at the epigenetic level, including transcription and protein processing. Accumulated data indicates its key role in protein homeostasis and other diverse functions involved in various ocular diseases, such as glaucoma, diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, achromatopsia, cataracts, ocular tumors, ocular surface diseases, and myopia. This review summarizes the molecular mechanisms underlying the aforementioned ocular diseases from an ER stress perspective. Drugs (chemicals, neurotrophic factors, and nanoparticles), gene therapy, and stem cell therapy are used to treat ocular diseases by alleviating ER stress. We delineate the advancement of therapy targeting ER stress to provide new treatment strategies for ocular diseases.
Topics: Humans; Endoplasmic Reticulum Stress; Unfolded Protein Response; Color Vision Defects; Autophagy; Epigenomics
PubMed: 37709773
DOI: 10.1038/s41392-023-01570-w -
Genetics in Medicine : Official Journal... Dec 2023CNGA3 encoding the main subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors is one of the major disease-associated genes for achromatopsia. Most...
PURPOSE
CNGA3 encoding the main subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors is one of the major disease-associated genes for achromatopsia. Most CNGA3 variants are missense variants with the majority being functionally uncharacterized and therefore hampering genetic diagnosis. In light of potential gene therapy, objective variant pathogenicity assessment is essential.
METHODS
We established a medium-throughput aequorin-based luminescence bioassay allowing mutant CNGA3 channel function assessment via quantification of CNGA3 channel-mediated calcium influx in a cell culture system, thereby enabling American College of Medical Genetics and Genomics/Association for Molecular Pathology-based variant re-classification.
RESULTS
We provide functional read-out obtained for 150 yet uncharacterized CNGA3 missense substitutions of which 55 were previously categorized as variants of uncertain significance (VUS) identifying 25 as functionally normal and 125 as functionally abnormal. These data enabled the American College of Medical Genetics and Genomics/ Association for Molecular Pathology-based variant re-classification of 52/55 VUS as either benign, likely benign, or likely pathogenic reaching a VUS re-classification rate of 94.5%.
CONCLUSION
Our aequorin-based bioassay allows functionally ensured clinical variant interpretation for 150 CNGA3 missense variants enabling and supporting VUS re-classification and assuring molecular diagnosis to patients affected by CNGA3-associated achromatopsia, hereby identifying patients eligible for future gene therapy trials on this disease.
Topics: Humans; Color Vision Defects; Aequorin; Retinal Cone Photoreceptor Cells; Mutation, Missense; Genomics; Cyclic Nucleotide-Gated Cation Channels
PubMed: 37689994
DOI: 10.1016/j.gim.2023.100979 -
PloS One 2023Colour-related search tasks are common in many professional fields. The study investigated whether increasing chromatic saturation can enhance the visual performance of...
BACKGROUND
Colour-related search tasks are common in many professional fields. The study investigated whether increasing chromatic saturation can enhance the visual performance of individuals with colour vision deficiency (CVD) in colour-related search tasks.
METHODS
10 normal trichromats (5M, 5F; Mean (SD) age: 23.1 (3.3) years) and 15 individuals with CVD [8 deutans and 7 protans identified by HRR plates] (14M, 1F; aged 28.6 (8.7) years) participated in this study. Four naturalistic sceneries of everyday tasks/ birds, animals and flowers of 15 different colour combinations (1 pair of colours in each combination. e.g., 'brown/black' or 'red/green') were presented in 'low' saturation, 'original' (unaltered images) and 'high' saturation condition using the Psychopy program on a colour-calibrated monitor. On each trial, the subject was asked to identify a specific-coloured target.
RESULTS
Overall, the visual search performance index (expressed as product of accuracy and a reciprocal of reaction time (%correct*s-1) of the normal trichromats [Mean (SD):77.76% correct*s-1 (16.32)] was significantly higher than CVD [45.71% correct*s-1 (18.95)] in the "original" test images (p = 0.001), but in individuals with CVD, there was no significant difference between 'original' [45.71% correct*s-1 (18.95)] and 'high' saturation condition ([47.43% correct*s-1 (20.07)]; p > 0.05). However, colour-wise, increased saturation showed improvements (≥ 10%) in protans mainly for 'red' combinations with other colours such as white (i.e., 'red/white'), purple, orange, grey, green, brown and black.
CONCLUSION
The study suggests that increasing the saturation of certain colour combinations can potentially aid in the visual search performance of individuals with CVD. This knowledge will help in better counselling and management of the patients.
Topics: Animals; Chemical Phenomena; Color Vision Defects; Flowers; Humans; Male; Female; Young Adult; Adult
PubMed: 37682873
DOI: 10.1371/journal.pone.0290782