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ABSTRACT A young woman presented at our clinic with sudden visual loss in the right eye, recurrent vertigo, and right-sided tinnitus. We performed a complete ophthalmological evaluation. This revealed effects of the condition on the small arterioles of the peripheral retina. Susac syndrome is characterized by the clinical triad of retinal arteriolar occlusions, cochleovestibular manifestations, and encephalopathy (which can be identified by neuroimaging abnormalities). Early diagnosis and immunosuppressive therapy improved the patient's visual acuity and the remission of her other symptoms. Hemi-central retinal artery occlusion is an atypical neuro-ophthalmological finding in this disease. However, its identification as a sign of Susac syndrome may facilitate timely diagnosis and accurate treatment.
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Exposure to the non-protein amino acid cyanotoxin ß-N-methylamino-L-alanine (BMAA), released by cyanobacteria found in many water reservoirs has been associated with neurodegenerative diseases. We previously demonstrated that BMAA induced cell death in both retina photoreceptors (PHRs) and amacrine neurons by triggering different molecular pathways, as activation of NMDA receptors and formation of carbamate-adducts was only observed in amacrine cell death. We established that activation of Retinoid X Receptors (RXR) protects retinal cells, including retina pigment epithelial (RPE) cells from oxidative stress-induced apoptosis. We now investigated the mechanisms underlying BMAA toxicity in these cells and those involved in RXR protection. BMAA addition to rat retinal neurons during early development in vitro increased reactive oxygen species (ROS) generation and polyADP ribose polymers (PAR) formation, while pre-treatment with serine (Ser) before BMAA addition decreased PHR death. Notably, RXR activation with the HX630 agonist prevented BMAA-induced death in both neuronal types, reducing ROS generation, preserving mitochondrial potential, and decreasing TUNEL-positive cells and PAR formation. This suggests that BMAA promoted PHR death by substituting Ser in polypeptide chains and by inducing polyADP ribose polymerase activation. BMAA induced cell death in ARPE-19 cells, a human epithelial cell line; RXR activation prevented this death, decreasing ROS generation and caspase 3/7 activity. These findings suggest that RXR activation prevents BMAA harmful effects on retinal neurons and RPE cells, supporting this activation as a broad-spectrum strategy for treating retina degenerations.
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Diamino Aminoácidos , Toxinas de Cianobactérias , Espécies Reativas de Oxigênio , Epitélio Pigmentado da Retina , Receptores X de Retinoides , Diamino Aminoácidos/farmacologia , Animais , Ratos , Espécies Reativas de Oxigênio/metabolismo , Receptores X de Retinoides/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/efeitos dos fármacos , Epitélio Pigmentado da Retina/citologia , Neurônios Retinianos/metabolismo , Neurônios Retinianos/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Humanos , Morte Celular/efeitos dos fármacosRESUMO
The purpose of this study was to analyze and molecularly describe the largest group of patients with ABCA4-associated retinal degeneration in Latin America. Pathogenic variants in ABCA4, a member of the ATP Binding Cassette (ABC) transporters superfamily, is one of the most common causes of inherited visual deficiency in humans. Retinal phenotypes associated with genetic defects in ABCA4 are collectively known as ABCA4-associated retinal degenerations (ABCA4R), a group of recessively inherited disorders associated with a high allelic heterogeneity. While large groups of Caucasian and Asiatic individuals suffering from ABCA4R have been well characterized, molecular information from certain ethnic groups is limited or unavailable, precluding a more realistic knowledge of ABCA4-related mutational profile worldwide. In this study, we describe the molecular findings of a large group of 211 ABCA4R index cases from Mexico. Genotyping was performed using either next generation sequencing (NGS) of a retinal dystrophy genes panel or exome. ABCA4 targeted mutation testing was applied to a subgroup of subjects in whom founder mutations were suspected. A total of 128 different ABCA4 pathogenic variants were identified, including 22 previously unpublished variants. The most common type of genetic variation was single nucleotide substitutions which occurred in 92.7% (408/440 alleles). According to the predicted protein effect, the most frequent variant type was missense, occurring in 83.5% of disease-causing alleles (368/440). Mutations such as p.Ala1773Val are fully demonstrated as a founder effect in native inhabitants of certain regions of Mexico. This study also gives us certain indications of other founder effects that need to be further studied in the near future. This is the largest molecularly characterized ABCA4R Latin American cohort, and our results supports the value of conducting genetic screening in underrepresented populations for a better knowledge of the mutational profile leading to monogenic diseases.
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Transportadores de Cassetes de Ligação de ATP , Genótipo , Degeneração Retiniana , Humanos , Transportadores de Cassetes de Ligação de ATP/genética , México , Masculino , Feminino , Degeneração Retiniana/genética , Criança , Mutação , Adulto , Adolescente , Pessoa de Meia-Idade , Sequenciamento de Nucleotídeos em Larga Escala , Alelos , Fenótipo , Pré-Escolar , Adulto Jovem , LinhagemRESUMO
Glaucoma, the leading cause of irreversible blindness worldwide, is a neurodegenerative disease characterized by chronic axonal damages and progressive loss of retinal ganglion cells, with increased intraocular pressure (IOP) as the primary risk factor. While current treatments focus solely on reducing IOP, understanding glaucoma through experimental models is essential for developing new therapeutic strategies and biomarkers for early diagnosis. Our research group developed an ocular hypertension rat model based on limbal plexus cautery, which provides significant glaucomatous neurodegeneration up to four weeks after injury. We evaluated long-term morphological, functional, and vascular alterations in this model. Our results showed that transient ocular hypertension, lasting approximately one week, can lead to progressive increase in optic nerve cupping and retinal ganglion cells loss. Remarkably, the pressure insult caused several vascular changes, such as arteriolar and venular thinning, and permanent choroidal vascular swelling. This study provides evidence of the longitudinal effects of a pressure insult on retinal structure and function using clinical modalities and techniques. The multifactorial changes reported in this model resemble the complex retinal ganglion cell degeneration found in glaucoma patients, and therefore may also provide a unique tool for the development of novel interventions to either halt or slow down disease progression.
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Modelos Animais de Doenças , Glaucoma , Pressão Intraocular , Células Ganglionares da Retina , Animais , Ratos , Glaucoma/fisiopatologia , Glaucoma/patologia , Células Ganglionares da Retina/patologia , Pressão Intraocular/fisiologia , Vasos Retinianos/patologia , Vasos Retinianos/fisiopatologia , Hipertensão Ocular/fisiopatologia , Hipertensão Ocular/patologia , Ratos Sprague-DawleyRESUMO
PURPOSE: To investigate the incidence and outcomes of retinal tear (RT) and retinal detachment (RD) after cataract extraction in patients with a history of previous phakic RT. DESIGN: Retrospective case series. PARTICIPANTS: Patients with phakic eyes with RT that were treated successfully with laser photocoagulation or cryotherapy and subsequently underwent cataract surgery. METHODS: A retrospective review of data between April 1, 2012, and May 31, 2023, was performed. Exclusions included prior vitreoretinal surgery before cataract removal and follow-up of less than 6 months after cataract surgery. MAIN OUTCOME MEASURES: The incidence of RTs and RDs after cataract surgery, along with visual and anatomic outcomes. RESULTS: Of 12 109 phakic eyes treated for RTs, 1039 eyes (8.6%) underwent cataract surgery. After exclusions, 713 eyes of 660 patients were studied. The mean ± standard deviation follow-up period after cataract surgery was 34.8 ± 24.6 months, with a median of 239 and 246 days to a new RT or RD development, respectively. The overall incidence of RT and RD diagnosis after cataract surgery was 7.3% (52/713; 2.9% and 4.3%, respectively), with a 1-year incidence of 5.6% (2.2% and 3.4%, respectively). Multivariable regression analysis identified a higher risk of RT and RD among younger individuals (odds ratio [OR], 1.034; P = 0.028), male patients (OR, 2.058; P = 0.022), and those with a shorter interval between laser treatment and cataract surgery (OR, 1.001; P = 0.011). Single-surgery anatomic success for the RD repair was achieved in 25 eyes (80.6%) at 3 months, with a 100% final reattachment rate. The median final visual acuity was 0.10 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, 20/25) for RT, showing no significant change from after cataract surgery, and 0.18 logMAR (Snellen equivalent, 20/30) for RD, a significant worsening from after cataract surgery. CONCLUSIONS: One year after cataract surgery, the rate of diagnosed RT and RD in patients with previously treated RTs was relatively high, occurring in nearly 1 in 18 eyes. Higher risk was noted among younger individuals, male patients, and patients with a shorter interval between initial treatment for RT and cataract surgery. Retinal detachment repair achieved good anatomic results, but vision declined. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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OBJECTIVE: The objective of the study is to compare the optic coherence tomography (OCT) parameters of the healthy and affected sides of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) and to investigate the relationships between these and the improvement in hearing levels. METHODS: A bilateral eye evaluation of patients diagnosed with ISSNHL was performed with OCT. The ganglion cell complex (GCC) and retina nerve fiber layer (RNFL) thickness values were recorded and the differences between the two eyes were examined. RESULTS: An evaluation was made of 39 patients with a mean age of 44.82 ± 14.90 years. The RNFL thickness of the eyes was determined to be mean 89.87 ± 3.65 µm on the affected side and 103.87 ± 3.98 µm on the healthy control side (p = 0.0001). The mean GCC was determined to be mean 90.46 ± 3.49 µm on the affected side and 103.77 ± 3.96 µm on the healthy control side (p = 0.0001). CONCLUSIONS: A statistically significant difference was observed between the healthy and affected eyes of patients with ISSNHL with respect to mean GCC and mean RNFL thickness. OCT could be a useful technique for measuring this neural degeneration.
OBJETIVO: Comparar e investigar los parámetros de la tomografía de coherencia óptica (OCT) de los lados sanos y afectados de pacientes con pérdida auditiva neurosensorial súbita idiopática (PANSI). MÉTODO: La evaluación ocular bilateral de los pacientes diagnosticados con PANSI se realizó con OCT. Se registraron los valores de espesor del complejo de células ganglionares (CCG) y de la capa de fibras nerviosas de la retina (CFNR), y se examinaron las diferencias entre los dos ojos. RESULTADOS: Se evaluaron 39 pacientes, con una edad media de 44.82 ± 14.90 años. Se determinó que el grosor de la CFNR de los ojos era una media de 89.87 ± 3.65 µm en el lado afectado y 103.87 ± 3.98 µm en el lado de control sano (p = 0.0001). Se determinó que el CCG medio era 90.46 ± 3.49 µm en el lado afectado y 103.77 ± 3.96 µm en el lado de control sano (p = 0.0001). CONCLUSIONES: Se encontró una diferencia estadísticamente significativa entre los ojos sanos y afectados de pacientes con PANSI con respecto al CCG medio y al espesor medio de la CFNR. La OCT podría ser una técnica útil para medir esta degeneración neuronal.
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Axônios , Fibras Nervosas , Tomografia de Coerência Óptica , Humanos , Tomografia de Coerência Óptica/métodos , Adulto , Feminino , Masculino , Fibras Nervosas/patologia , Pessoa de Meia-Idade , Axônios/patologia , Células Ganglionares da Retina/patologia , Perda Auditiva Neurossensorial/diagnóstico por imagem , Perda Auditiva Súbita/diagnóstico por imagem , Adulto JovemRESUMO
BACKGROUND: Retinopathy of Prematurity (ROP) is a proliferative retinal vascular disease occurring in the retina of premature infants and is the main cause of childhood blindness. Nowadays anti-VEGF and retinal photocoagulation are mainstream treatments for ROP, but they develop a variety of complications. Hydrogen (H2) is widely considered as a useful neuroprotective and antioxidative therapeutic method for hypoxic-ischemic disease without toxic effects. However, whether H2 provides physiological angiogenesis promotion, neovascularization suppression and glial protection in the progression of ROP is largely unknown.This study aims to investigate the effects of H2 on retinal angiogenesis, neovascularization and neuroglial dysfunction in the retinas of oxygen-induced retinopathy (OIR) mice. METHODS: In this study, mice that were seven days old and either wild-type (WT) or Nrf2-deficient (Nrf2-/-) were exposed to 75% oxygen for 5 days and then returned to normal air conditions. Different stages of hydrogen gas (H2) inhalation were administered. Vascular obliteration, neovascularization, and blood vessel leakage were analyzed and compared. To count the number of neovascularization endothelial nuclei, routine HE staining of retinal sections was conducted. Immunohistochemistry was performed using DyLight 594 labeled GSL I-isolectin B4 (IB4), as well as primary antibodies against proliferating cell nuclear antigen (PCNA), glial fibrillary acidic protein (GFAP), and Iba-1. Western blots were used to measure the expression of NF-E2-related factor 2 (Nrf2), vascular endothelial growth factor (VEGF), Notch1, Dll4, and HIF-1α. Additionally, the expression of target genes such as NQO1, HO-1, Notch1, Hey1, Hey2, and Dll4 was measured. Human umbilical vein endothelial cells (HUVECs) treated with H2 under hypoxia were used as an in vitro model. RT-PCR was used to evaluate the mRNA expression of Nrf2, Notch/Dll4, and the target genes. The expression of reactive oxygen species (ROS) was observed using immunofluorescence staining. RESULTS: Our results indicate that 3-4% H2 does not disturb retinal physiological angiogenesis, but ameliorates vaso-obliteration and neovascularization in OIR mice. Moreover, H2 prevents the decreased density and reverses the morphologic and functional changes in retinal astrocytes caused by oxygen-induced injury. In addition, H2 inhalation reduces microglial activation, especially in the area of neovascularization in OIR mice. H2 plays a protective role in vascular regeneration by promoting Nrf2 activation and suppressing the Dll4-induced Notch signaling pathway in vivo. Also, H2 promotes the proliferation of HUVECs under hypoxia by negatively regulating the Dll4/Notch pathway and reducing ROS levels through Nrf2 pathway aligning with our findings in vivo.Moreover, the retinal oxygen-sensing mechanisms (HIF-1α/VEGF) are also involved in hydrogen-mediated retinal revascularization and neovascularization suppression. CONCLUSIONS: Collectively, our results indicate that H2 could be a promising therapeutic agent for POR treatment and that its beneficial effect in human ROP might involve the activation of the Nrf2-Notch axis as well as HIF-1α/VEGF pathways.
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Modelos Animais de Doenças , Hidrogênio , Neuroglia , Oxigênio , Neovascularização Retiniana , Retinopatia da Prematuridade , Animais , Hidrogênio/farmacologia , Neovascularização Retiniana/tratamento farmacológico , Neuroglia/efeitos dos fármacos , Camundongos , Retinopatia da Prematuridade/tratamento farmacológico , Camundongos Endogâmicos C57BL , Retina/efeitos dos fármacos , Animais Recém-Nascidos , Regeneração/efeitos dos fármacos , Imuno-Histoquímica , Vasos Retinianos/efeitos dos fármacosRESUMO
Macular holes (MHs), including atraumatic idiopathic and refractory MHs, affect central vision acuity due to full-thickness defects in the retinal tissue. The existing controversy regarding the pathophysiology and management of MHs has significantly improved with the implementation of internal limiting membrane (ILM) surgical techniques and improved MH closure rates. Thus, to determine the effect of ILM techniques on large idiopathic and refractory MH management, the present study systematically reviewed 5910 original research articles extracted from online literature databases, including PubMed, Cochrane, Google Scholar, and Embase, following the PRISMA guidelines. The primary outcome measures were MH closure rate and postoperative visual acuity. A total of 23 randomized controlled trials (RCTs) with adequate patient information and information on the effect of ILM peeling, inverted ILM flaps, autologous retinal transplantation (ART), and ILM insertion techniques on large idiopathic and refractory MH patients were retrieved and analyzed using RevMan software (version 5.3) provided by the Cochrane Collaboration. Statistical risk of bias analysis was also conducted on the selected sources using RoB2, which showed a low risk of bias in the included studies. A meta-analysis indicated that the inverted ILM flap technique had a significantly greater MH closure rate for primary MH than the other treatment methods (OR = 3. 22, 95% CI 1.34-7.43; p = 0.01). Furthermore, the findings showed that the inverted ILM flap group had significantly better postoperative visual acuity than did the other treatment options for patients with idiopathic MH (WMD = - 0.13; 95% CI = 0.22-0.09; p = 0.0002). The ILM peeling technique had the second highest statistical significance for MH closure rates in patients with idiopathic MH (OR = 2. 72, 95% CI: 1.26-6.32; p = 0.016). In refractory MHs, autologous retinal transplant (ART) and multilayer ILM plug (MIP) techniques improve the closure rate and visual function; human amniotic membrane grafting (hAMG) provides a high degree of anatomical outcomes but disappointing visual results. This study demonstrated the reliability and effectiveness of ILM techniques in improving the functional and anatomical outcomes of large idiopathic and refractory MH surgery. These findings will help clinicians choose the appropriate treatment technique for patients with idiopathic and refractory MH.
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BACKGROUND: Diabetic retinopathy (DR) stands as the foremost cause of preventable blindness in adults. Despite efforts to expand DR screening coverage in the Brazilian public healthcare system, challenges persist due to various factors including social, medical, and financial constraints. Our objective was to evaluate the quality of images obtained with the AirDoc, a novel device, compared to Eyer portable camera which has already been clinically validated. METHODS: Images were captured by two portable retinal devices: AirDoc and Eyer. The included patients had their fundus images obtained in a screening program conducted in Blumenau, Santa Catarina. Two retina specialists independently assessed image's quality. A comparison was performed between both devices regarding image quality and the presence of artifacts. RESULTS: The analysis included 129 patients (mean age of 61 years), with 29 (43.28%) male and an average disease duration of 11.1 ± 8 years. In Ardoc, 21 (16.28%) images were classified as poor quality, with 88 (68%) presenting artifacts; in Eyer, 4 (3.1%) images were classified as poor quality, with 94 (72.87%) presenting artifacts. CONCLUSIONS: Although both Eyer and AirDoc devices show potential as screening tools, the AirDoc images displayed higher rates of ungradable and low-quality images, that may directly affect the DR and DME grading. We must acknowledge the limitations of our study, including the relatively small sample size. Therefore, the interpretations of our analyses should be approached with caution, and further investigations with larger patient cohorts are warranted to validate our findings.
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Leber congenital amaurosis (LCA)/early-onset severe retinal dystrophy (EOSRD) stand as primary causes of incurable childhood blindness. This study investigates the clinical and molecular architecture of syndromic and non-syndromic LCA/EOSRD within a Chilean cohort (67 patients/60 families). Leveraging panel sequencing, 95.5% detection was achieved, revealing 17 genes and 126 variants (32 unique). CRB1, LCA5, and RDH12 dominated (71.9%), with CRB1 being the most prevalent (43.8%). Notably, four unique variants (LCA5 p.Glu415*, CRB1 p.Ser1049Aspfs*40 and p.Cys948Tyr, RDH12 p.Leu99Ile) constituted 62.7% of all disease alleles, indicating their importance for targeted analysis in Chilean patients. This study underscores a high degree of inbreeding in Chilean families affected by pediatric retinal blindness, resulting in a limited mutation repertoire. Furthermore, it complements and reinforces earlier reports, indicating the involvement of ADAM9 and RP1 as uncommon causes of LCA/EOSRD. These data hold significant value for patient and family counseling, pharmaceutical industry endeavors in personalized medicine, and future enrolment in gene therapy-based treatments, particularly with ongoing trials (LCA5) or advancing preclinical developments (CRB1 and RDH12).
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Mutação , Distrofias Retinianas , Humanos , Distrofias Retinianas/genética , Distrofias Retinianas/terapia , Distrofias Retinianas/diagnóstico , Chile/epidemiologia , Masculino , Feminino , Criança , Pré-Escolar , Oxirredutases do Álcool/genética , Proteínas de Membrana/genética , Proteínas do Olho/genética , Amaurose Congênita de Leber/genética , Amaurose Congênita de Leber/terapia , Amaurose Congênita de Leber/diagnóstico , Linhagem , Proteínas do Tecido Nervoso/genética , Adolescente , Alelos , Variação Genética , Oftalmopatias HereditáriasRESUMO
Complications from diabetic retinopathy such as diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) constitute leading causes of preventable vision loss in working-age patients. Since vascular endothelial growth factor (VEGF) plays a major role in the pathogenesis of these complications, VEGF inhibitors have been the cornerstone of their treatment. Anti-VEGF monotherapy is an effective but burdensome treatment for DME. However, due to the intensive and burdensome treatment, most patients in routine clinical practice are undertreated, and therefore, their outcomes are compromised. Even in adequately treated patients, persistent DME is reported anywhere from 30% to 60% depending on the drug used. PDR is currently treated by anti-VEGF, panretinal photocoagulation (PRP) or a combination of both. Similarly, a number of eyes, despite these treatments, continue to progress to tractional retinal detachment and vitreous hemorrhage. Clearly there are other molecular pathways other than VEGF involved in the pathogenesis of DME and PDR. One of these pathways is the angiopoietin-Tie signaling pathway. Angiopoietin 1 (Ang1) plays a major role in maintaining vascular quiescence and stability. It acts as a molecular brake against vascular destabilization and inflammation that is usually promoted by angiopoietin 2 (Ang2). Several pathological conditions including chronic hyperglycemia lead to Ang2 upregulation. Recent regulatory approval of the bi-specific antibody, faricimab, may improve long term outcomes in DME. It targets both the Ang/Tie and VEGF pathways. The YOSEMITE and RHINE were multicenter, double-masked, randomized non-inferiority phase 3 clinical trials that compared faricimab to aflibercept in eyes with center-involved DME. At 12 months of follow-up, faricimab demonstrated non-inferior vision gains, improved anatomic outcomes and a potential for extended dosing when compared to aflibercept. The 2-year results of the YOSEMITE and RHINE trials demonstrated that the anatomic and functional results obtained at the 1 year follow-up were maintained. Short term outcomes of previously treated and treatment-naive eyes with DME that were treated with faricimab during routine clinical practice suggest a beneficial effect of faricimab over other agents. Targeting of Ang2 has been reported by several other means including VE-PTP inhibitors, integrin binding peptide and surrobodies.
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BACKGROUND: To describe the phenotype and genotype of 10 Brazilian patients with variants in MFRP, posterior microphthalmos and retinal findings. METHODS: Complete ophthalmological evaluation was done at 4 different Brazilian centers. Genetic analysis was performed using commercial next generation sequencing panels for inherited retinal disorders. RESULTS: Ages of the patients ranged from 10 to 65 years and visual acuities from 0,05 to no perception of light. All were hyperopes (+4,25 to + 17,50) with a short axial length (14,4 mm to 18 mm). Common posterior segment features, though not present in all, were optic disc drusen (5/10), foveoschisis (5/10) and retinal pigmentary changes (8/10). Isolated patients presented with macular atrophy, serous retinal detachment, and chorioretinal folds. The most common variant in MFRP found in our patients was a deletion in exon 5 (c.498delC; p.Asn267Thrfs *25), present in all except 2 patients. Other variants found were c.523C>T (p.Gln175*), c.298delG (p.Ala100Argfs *37), c.666del (p.Thr223Argfs *83) and the novel variant c.257C>A (p.Ala86Asp). CONCLUSIONS: This is the first report of Brazilian patients with posterior microphthalmos and pathogenic variants in MFRP and the first describe of the variant p.Ala86Asp in literature. Our cases confirm the previously reported phenotype of high hyperopia, optic disc drusen, alterations in foveal architecture, retinal pigmentary changes with loss of photoreceptor function and visual field constriction. Report of such a rare condition is important to increase awareness to the phenotype of posterior microphthalmia with associated retinal conditions.
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Microftalmia , Humanos , Microftalmia/genética , Microftalmia/patologia , Feminino , Masculino , Criança , Adulto , Adolescente , Pessoa de Meia-Idade , Brasil , Idoso , Adulto Jovem , Proteínas de Membrana/genética , Fenótipo , Acuidade Visual/fisiologia , Oxirredutases do Álcool/genética , Doenças Retinianas/genética , Doenças Retinianas/diagnóstico , Mutação , GenótipoRESUMO
Non-exudative age-related macular degeneration (NE-AMD) is the leading blindness cause in the elderly. Clinical and experimental evidence supports that early alterations in macular retinal pigment epithelium (RPE) mitochondria play a key role in NE-AMD-induced damage. Mitochondrial dynamics (biogenesis, fusion, fission, and mitophagy), which is under the central control of AMP-activated kinase (AMPK), in turn, determines mitochondrial quality. We have developed a NE-AMD model in C57BL/6J mice induced by unilateral superior cervical ganglionectomy (SCGx), which progressively reproduces the disease hallmarks circumscribed to the temporal region of the RPE/outer retina that exhibits several characteristics of the human macula. In this work we have studied RPE mitochondrial structure, dynamics, function, and AMPK role on these parameters' regulation at the nasal and temporal RPE from control eyes and at an early stage of experimental NE-AMD (i.e., 4 weeks post-SCGx). Although RPE mitochondrial mass was preserved, their function, which was higher at the temporal than at the nasal RPE in control eyes, was significantly decreased at 4 weeks post-SCGx at the same region. Mitochondria were bigger, more elongated, and with denser cristae at the temporal RPE from control eyes. Exclusively at the temporal RPE, SCGx severely affected mitochondrial morphology and dynamics, together with the levels of phosphorylated AMPK (p-AMPK). AMPK activation with metformin restored RPE p-AMPK levels, and mitochondrial dynamics, structure, and function at 4 weeks post-SCGx, as well as visual function and RPE/outer retina structure at 10 weeks post-SCGx. These results demonstrate a key role of the temporal RPE mitochondrial homeostasis as an early target for NE-AMD-induced damage, and that pharmacological AMPK activation could preserve mitochondrial morphology, dynamics, and function, and, consequently, avoid the functional and structural damage induced by NE-AMD.
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Proteínas Quinases Ativadas por AMP , Modelos Animais de Doenças , Degeneração Macular , Camundongos Endogâmicos C57BL , Mitocôndrias , Dinâmica Mitocondrial , Epitélio Pigmentado da Retina , Animais , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Camundongos , Degeneração Macular/patologia , Degeneração Macular/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/patologia , Proteínas Quinases Ativadas por AMP/metabolismo , Humanos , Metformina/farmacologiaRESUMO
Introduction: Platelet-activating factor (PAF), PAF receptor (PAFR), and PAF- synthesis/degradation systems are involved in essential CNS processes such as neuroblast proliferation, differentiation, migration, and synaptic modulation. The retina is an important central nervous system (CNS) tissue for visual information processing. During retinal development, the balance between Retinal Progenitor Cell (RPC) proliferation and differentiation is crucial for proper cell determination and retinogenesis. Despite its importance in retinal development, the effects of PAFR deletion on RPC dynamics are still unknown. Methods: We compared PAFR knockout mice (PAFR-/-) retinal postnatal development proliferation and differentiation aspects with control animals. Electrophysiological responses were analyzed by electroretinography (ERG). Results and discussion: In this study, we demonstrate that PAFR-/- mice increased proliferation during postnatal retinogenesis and altered the expression of specific differentiation markers. The retinas of postnatal PAFR-/- animals decreased neuronal differentiation and synaptic transmission markers, leading to differential responses to light stimuli measured by ERG. Our findings suggest that PAFR signaling plays a critical role in regulating postnatal RPC cell differentiation dynamics during retinal development, cell organization, and neuronal circuitry formation.
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BACKGROUND: Rhegmatogenous retinal detachment (RRD) is a serious condition that occurs when the retina detaches from its underlying retinal pigment epithelium. RRDs associated with giant retinal tears (GRTs) are caused by retinal tears at least 90° or one-quarter of the circumferential extent. This scoping review systematically identifies and summarizes clinical studies evaluating surgical techniques for the management of GRT-related RRDs, discusses functional and visual outcomes and the risk factors affecting treatment outcomes. METHODS: This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, Google Scholar, and Springer Link databases were searched for relevant papers (from January 2001 to March 2023). Studies that were published in the English language and reported the risk factors, management, and treatment outcomes of GRT-related RRDs were included in the review. The outcome measures included anatomic success rates, changes in BCVA (logMAR) from baseline to the final follow-up, and adverse events. RESULTS: A total of 11,982 articles were identified. After the title and abstract review, 71 studies were deemed eligible for full-text review. Thirty-six studies that met the eligibility criteria were included in the final review. Four surgical techniques were identified: pars plana vitrectomy (PPV), combined PPV and scleral buckling, scleral buckling alone, and pneumatic retinopexy. Various types of tamponades, including gas, silicone oil, and air, have been used. PPV was the most commonly used surgical technique in 33.1-100% of patients. Among the 20 studies that used PPV alone, 17 were associated with preoperative PVR. In addition, scleral buckling alone or in combination with PPV was reported as a treatment option in 10 studies, with 2-100% of patients experiencing scleral buckling alone and 13.6-100% experiencing combined PPV and complementary scleral buckling. Primary anatomic success (PAS) was achieved with retinal reattachment via a single operation with no residual tamponade, whereas final anatomic success (FAS) was achieved via more than one operation with no residual tamponade. Reported single surgery anatomic success (SSAS) rates range from 65.51 to 100%. The preoperative best-corrected visual acuity (BCVA) ranged from 0.067 to 2.47 logMAR, whereas the postoperative BCVA ranged from 0.08 to 2.3 logMAR. An improvement in visual acuity was observed in 29 studies. Cataracts (3.9-28.3%) were the most common postoperative complication, followed by high IOP (0.01-51.2%) and PVR (0.8-31.57%). CONCLUSION: PPV is the most common surgical technique, and currently microincision vitrectomy surgery (MIVS) systems are commonly employed. Silicone oil is the most frequently used tamponade in RRD repair. Risk factors for GRT-related RRD include age, sex, lens status, high myopia status, proliferative vitreoretinopathy (PVR), presenting visual acuity, the extent of the GRT and retinal detachment, and macular involvement. Future research areas include guidelines to reduce variability in the reporting of surgical methodology, choice of tamponades, and reporting of functional and visual outcomes to inform the best therapeutic interventions in GRT-related RRD.
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BACKGROUND: Describe complications and clinical outcomes of heavy silicone oil (HSO) Oxane HD® use as an alternative to overcome the challenges of performing vitrectomy to treat tractional and rhegmatogenous retinal detachments with proliferative vitreoretinopathy (PVR). METHODS: A retrospective, observational study was performed on patients from one center from August 2014 to Aug 2023. It was included patients who underwent surgery using HSO Oxane HD® to treat rhegmatogenous retinal detachment with PVR or mixed tractional and rhegmatogenous diabetic retinal detachment. Severely ill patients who could not attend to follow up were excluded. The primary outcome was successful retinal attachment at first postoperative month. A descriptive analysis was performed. RESULTS: Among the 31 patients, 29 (93.5%) underwent surgeries due to rhegmatogenous retinal detachment and two (6.5%) for diabetic retinal detachment. The primary anatomic success was achieved in 27 (87.1%) patients. At the final visit, 17 (56.6%) had vision better than 20/400 (range, 20/30 to light perception). The vision was stable or improved in 22 (76.8%) patients at the end of follow-up. Nineteen (61.3%) patients required hypotensive eye drops after HSO use and twelve (38.7%) still required hypotensive eye drops at the final follow-up; three (9.7%) patients required additional glaucoma surgeries. CONCLUSIONS: HSO is safe and useful for complex retinal detachments cases specially with inferior tears and PVR. Ocular hypertension is frequent and usually clinically controlled with hypotensive eyedrops. Close postoperatively follow-up is advised due to the ocular complications, particularly elevated intraocular pressure and emulsification.
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PURPOSE: To assess the relationship between macular choroidal thickness (CT) measurements and retinal sensitivity (RS) in eyes with myopia and different stages of myopic maculopathy. METHODS: A masked, cross-sectional, and consecutive study involving patients with emmetropia/myopia (control group) and high myopia (HM) eyes. Automated choroidal thickness (CT) and manual outer retinal layer (ORL) thickness were acquired using swept-source optical coherence tomography, while retinal sensitivity (RS) assessed by microperimetry (MP3) in all regions of the macular Early Treatment Diabetic Retinopathy Study (ETDRS) grid. Comparisons were made between groups, and correlations were performed among these measurements, demographic and ocular parameters and myopic maculopathy classification. RESULTS: A total of 37 (74 eyes) patients were included in the study. The mean age was 39 ± 13 years, and 28 patients (76%) were female. HM eyes exhibited inferior best-corrected visual acuity and a more advanced myopic maculopathy classification compared to the control group. The mean macular CT were 255 and 179 µm in the control and HM eyes (P < 0.001), respectively. In the HM eyes, superior ETDRS region presented the greatest values. Mean RS in control and HM groups was 28 and 24 dB (P = 0.001), respectively. Inner temporal followed by superior, were the regions of higher RS. Mean ORL thickness was 83 and 79 µm (P < 0.001), in the control and HM groups, respectively. The inner temporal ETDRS region presented the thickest measure. CT correlated significantly with RS (r = 0.41, P < 0.001) and ORL thickness, (r = 0.58, P < 0.001), which also correlated with RS (r = 0.40, P < 0.001). Spherical equivalent, axial length and myopic maculopathy stage were the parameters that most correlated with CT, RS and ORL thickness. For every 100 µm increase in thickening of CT there was an average increase of 3.4 µm in ORL thickness and 2.7 dB in RS. Myopic maculopathy classification demonstrated influence only with CT. CONCLUSION: Myopia degree is related to ORL and choroidal thinning and deterioration of retinal sensitivity in some ETDRS regions of the macula. Choroidal thinning is associated to with a decline of retinal sensitivity, thinning of ORL, and worsening of myopic maculopathy classification, so new treatments are necessary to prevent myopia progression.
RESUMO
The retina is a central nervous tissue essential to visual perception and highly susceptible to environmental damage. Lower vertebrate retinas activate intrinsic regeneration mechanisms in response to retinal injury regulated by a specialized population of progenitor cells. The mammalian retina does not have populations of progenitor/stem cells available to activate regeneration, but contains a subpopulation of differentiated cells that can be reprogrammed into retinal stem cells, the ciliary epithelium (CE) cells. Despite the regenerative potential, stem cells derived from CE exhibit limited reprogramming capacity probably associated with the expression of intrinsic regulatory mechanisms. Platelet-activating factor (PAF) is a lipid mediator widely expressed in many cells and plays an important role in stem cell proliferation and differentiation. During mammalian development, PAF receptor signaling showed important effects on retinal progenitors' cell cycle regulation and neuronal differentiation that need to be further investigated. In this study, our findings suggested a dynamic role for PAF receptor signaling in CE cells, impacting stem cell characteristics and neurosphere formation. We showed that PAF receptors and PAF-related enzymes are downregulated in retinal progenitor/stem cells derived from PE cells. Blocking PAFR activity using antagonists increased the expression of specific progenitor markers, revealing potential implications for retinal tissue development and maintenance.
Assuntos
Glicoproteínas da Membrana de Plaquetas , Receptores Acoplados a Proteínas G , Retina , Células-Tronco , Animais , Proliferação de Células , Células-Tronco/metabolismo , Epitélio , MamíferosRESUMO
BACKGROUND: Myopic traction maculopathy (MTM) is a complication of pathological myopia and encompasses various pathological conditions caused by tractional changes in the eye. These changes include retinoschisis, foveal retinal detachment, and lamellar or full-thickness macular holes (FTMHs). This meta-analysis evaluated the safety and efficacy of novel surgical for treating MTM. METHODS: To compare the outcomes of different surgical approaches for MTM, multiple databases, including Web of Science, PubMed, Scopus, ClinicalTrials.gov, the Cochrane Central Register of Controlled Trials, Ovid MEDLINE, Embase, and the Meta-Register of Controlled Trials, were comprehensively searched. The meta-analysis was performed using RevMan 5.1. RESULTS: Nine comparative studies involving 350 eyes were included in this meta-analysis. There were significant differences between fovea-sparing internal limiting membrane peeling (FSIP) and standard internal limiting membrane peeling (ILMP). Preoperative best-corrected visual acuity BCVA (standard mean difference (SMD): -0.10, 95% CI: -0.32 to 0.12) and central foveal thickness CFT (SMD: 0.05, 95% CI: -0.22 to 0.33) were not significantly different (p = 0.39 and p = 0.71, respectively). However, the postoperative BCVA improved significantly (SMD = - 0.47, 95% CI: - 0.80, - 0.14, p = 0.006) in the FSIP group compared to the standard ILMP group. Postoperative CFT did not differ significantly between the two groups (p = 0.62). The FSIP group had a greater anatomical success rate than the other groups, although the difference was not statistically significant (p = 0.26). The incidence of postoperative macular hole formation was significantly lower (OR = 0.19, 95% CI = 0.07-0.54; p = 0.05) in the FSIP group than in the standard ILMP group. The unique characteristics of highly myopic eyes, such as increased axial length and structural changes, may have contributed to the greater incidence of FTMH in the ILMP group. CONCLUSION: Based on the findings of this meta-analysis, FSIP is the initial surgical approach for early-stage MTM and has shown promising outcomes. However, to establish the safest and most efficient surgical technique for treating different MTM stages, further comparative studies, specifically those focusing on ILMP and FSIP, are necessary. TRIAL REGISTRATION: Retrospectively registered.