Ocular toxoplasmosis (OT), caused by Toxoplasma gondii, is the leading cause of retinochoroiditis worldwide, with particularly severe cases in Brazil. The treatment used for OT is the combination of cotrimoxazole and corticosteroids. However, this therapy includes prolonged treatment, resistance to circulating strains, and cytotoxic effects for patients. The intensification of the inflammatory response against T. gondii can exacerbate retinal tissue damage. In this study, the HDAC6 inhibitor Tubastatin A was evaluated by intravitreal injection in the murine ocular toxoplasmosis model. Tubastatin A has presented anti-T. gondii activity and an interesting potential for immunoregulation in the approach to eye disease. The inhibition of HDAC6 interferes with the establishment of infection by blocking the recruitment of the host cell cytoskeleton, which is necessary for the active entry of tachyzoites. After 5 days of treatment, Tubastatin A prevented the progression of lesions in the infected retina from the 10th postinfection day. Tubastatin A restored retinal tissue barriers and regulated the HDAC6-Hsp90 pathway, leading to decreased VEGF and HSF1 expression, which may help prevent neovascularization observed in OT patients. A single intravitreal dose of Tubastatin A established an anti-inflammatory microenvironment that supported retinal tissue homeostasis. Tubastatin regulated micro- and macroglial activation, reduced immunolabeling of Iba1 and GFAP (glial fibrillary acidic), and decreased the secretion of IL-12, IL-4, and IL-17A, key cytokines associated with OT pathology. The combination of Tubastatin A with antifolates may be a viable new treatment regimen to protect retinal tissue and prevent blindness in patients.

There are limited surgical options to successfully close a refractory macular hole. One promising option is an autologous neurosensory retinal free flap transplantation. An autologous neurosensory retinal free flap transplantation places a graft of peripheral autologous retinal tissue into the macular hole and was developed to improve post-surgical outcomes. Here, clinical instrumentation and a high-resolution adaptive optics system imaged the graft and host tissue of a patient whose refractory macular hole was successfully closed with an autologous neurosensory retinal free flap transplantation. A 71-year-old Hispanic female with bilateral moderate nonproliferative diabetic retinopathy (visual acuity of 20/100 in each eye) underwent an autologous neurosensory retinal free flap transplantation in the right eye only, which successfully closed a large refractory macular hole measuring 4° in diameter. Although somewhat variable, the best-corrected visual acuity improved from 20/100 to 20/70 with a subjective improvement noted by the patient. The eye was examined using (1) fundus photography and (2) clinical optical coherence tomography both presurgery and post surgery and (3) with adaptive optics-optical coherence tomography-scanning laser ophthalmoscopy post surgery. Postsurgical clinical optical coherence tomography imaging revealed restoration of the external limiting membrane within the graft. Adaptive optics-optical coherence tomography imaging provided enhanced lateral and axial resolution and showed a restored inner segment/outer segment junction within the graft. Adaptive optics-optical coherence tomography also revealed the cone outer segment tip layer in the host tissue, highlighting preservation of the microarchitecture and indicating that the host tissue was not negatively impacted by the surgery or the presence of the graft. Further, adaptive optics-scanning laser ophthalmoscopy imaging revealed photoreceptors within the graft and surrounding host tissue, indicating surgical success, graft acceptance and viable host tissue. Although the exact physiological mechanisms that promote macular hole closure and intraretinal cellular changes after an autologous neurosensory retinal free flap transplantation are unknown, imaging supports the procedure as a reasonable surgical option for refractory macular hole closure. The preserved integrity of the host tissue suggests that the graft does not negatively impact the retina following the surgery. Furthermore, the improvement in the inner segment/outer segment junction and external limiting membrane noted over time within the graft are considered favorable as they relate to the structure and function of the retina.

Chronic inflammation is closely linked to retinal ganglion cell (RGC) damage in glaucoma. However, naturally derived biomaterials often lack sufficient anti-inflammatory activity and fail to effectively support RGC survival. In this study, we developed a stem cell-loaded, nanovesicle-integrated sericin-based hydrogel, SerMA-PC@PNVs, designed to enhance the survival of RGCs in glaucomatous conditions. Nanovesicles (NVs) derived from periodontal ligament stem cells (PDLSCs) were obtained via ultracentrifugation and liposome extrusion. These NVs were loaded with procyanidins (PC) and functionalized with acrylate-polyethylene glycol-N-hydroxysuccinimide (AC-PEG-NHS). The modified NVs (PC@PNVs) were then covalently grafted onto methacrylated sericin (SerMA) through a photo-cross-linking reaction to form the SerMA-PC@PNVs hydrogel scaffold. In vitro studies demonstrated that the SerMA-PC@PNV scaffold enhanced the secretion of neurotrophic factors by encapsulated PDLSCs. Both in vitro and in vivo results confirmed that the SerMA-PC@PNVs/PDLSCs hydrogel effectively reprogrammed microglial polarization from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype, thereby creating a neuroprotective microenvironment favorable for RGC survival. Mechanistically, RNA sequencing of retinal tissues revealed significant regulation of pathways associated with the "inflammatory response" and "apoptotic process". Single-cell RNA sequencing further demonstrated an increase in RGC populations and a reduction in neutrophils and microglia following treatment. Microglial subclustering analysis validated the hydrogel's regulatory effects on "inflammatory response" signaling. In conclusion, the SerMA-PC@PNVs/PDLSCs can promote the survival of glaucoma-damaged RGCs by regulating the inflammatory response.

Suppression of HIF-1α alleviates the symptoms associated with diabetic retinopathy in mice.

3D Structural Phenotype of the Optic Nerve Head in Glaucoma and Myopia-A Key to Improving Glaucoma Diagnosis in Myopic Populations.

Full-length spatial transcriptome strategy based on robust and low-cost target tissue capture.

Multiomics data reveal microglia's promotion for choroidal neovascularization in endothelial cells.

Differential expression of VGLUT1, GAD65, GAD67, and MAP2 in the retina of hibernating Anatolian ground squirrel (Spermophilus xanthoprymnus).

Zinc transporter proteins in the retina as potential biomarkers for staging early Alzheimer's disease: Comparative analysis in human and mouse models.

Diabetic retinopathy (DR), a common complication of diabetes, is a leading cause of blindness globally. Cytochrome C oxidase copper chaperone (COX17) is important for Cytochrome C oxidase assembly, and COX17 overexpression is reported to improve mitochondrial function in renal tissue. This study aimed to explore whether COX17 alleviated DR by regulating mitochondrial function. Diabetes was induced in rats by a single intraperitoneal injection of 65 mg/kg streptozotocin (STZ). Overexpression of COX17 was performed by infection of adeno-associated virus into the vitreous body of rats 2 weeks after STZ injection. Human retinal microvascular endothelial cells (HRMECs) were cultured with high-glucose (HG) medium (20 mM d-glucose). Immunofluorescence assay, enzymatic histochemistry assay, CCK-8 assay, DCFH-DA staining, flow cytometry, western blot, and real-time PCR were performed. COX17 expression was decreased in the retinal tissues of diabetic rats and HG-stimulated HRMECs. COX17 overexpression alleviated retinal neovascularisation and increased retinal thickness in diabetic rats. COX17 overexpression decreased ROS and apoptosis and increased Cytochrome C oxidase activity, mtDNA copy number, ATP content, and mitochondrial membrane potential (MMP) in both the retinal tissues of diabetic rats and HG-induced HRMECs. Overexpression of COX17 effectively reduced cell apoptosis and increased cell viability. Overexpression of COX17 increased mtDNA in HG-induced HRMECs. Overall, our study suggested that COX17 overexpression exerted protective effects in the retinas of diabetic rats and in HRMECs by stabilising mitochondrial function.

Pigmentation varies widely across humans and is shaped by melanin quantity, type, and spatial distribution. Retinal pigmentation protects against light-induced damage, yet its genetic and evolutionary bases remain unclear. We developed a deep learning framework (DeepGRP) to quantify retinal pigmentation from high-resolution fundus images and conducted a genome-wide association study (GWAS), identifying 42 signals, including 26 previously unidentified loci, with single-nucleotide polymorphism–based heritability of 21.4%. Single-nucleus assay for transposase-accessible chromatin by sequencing and RNA sequencing of human fetal retinal tissues revealed key cellular contributors, including retinal pigment epithelium and photoreceptor cells. Among candidate genes, ARHGAP18 emerged as a previously unrecognized regulator of melanogenesis. Evidence of polygenic adaptation in Europeans suggests selection driven by snow-reflected light at high latitudes. A polygenic risk score for retinal pigmentation correlated with a 4.8-fold higher risk of myopia and a 1.5-fold lower risk of skin cancer. These findings demonstrate the power of deep learning for large-scale ocular phenotyping and reveal insights into the genetic and evolutionary architecture of retinal pigmentation.

Objective: The objective of this study was to evaluate the efficacy of intravenous lipid emulsion (ILE) application in comparison to ethanol in the treatment of optic neuropathy resulting from acute methanol intoxication in rats. Methods: 64 male rats were divided into 7 groups: Group 1 (control group), Group 2 (methanol group), Group 3 (methanol + ethanol group), Group 4 (methanol + ILE group), Group 5 (methanol + ethanol + ILE group), Group 6 (ethanol group), and Group 7 (ILE group). Blood samples were taken to analysis liver and kidney function. The rats were sacrificed. The optic nerve and retina were examined histologically. Results: The combination of methanol, ethanol, and ILE has a positive effect on LDH and CK-MB levels. Histopathologically, marked vascularization and vacuolization were observed in the optic nerve in the methanol group. These changes were not significant in the group receiving methanol, intravenous lipid emulsion, and ethanol together. ILE and ethanol did not cause any significant apoptotic changes in the retina (p=0.357). Significant edema, vascularization, apoptotic changes, and vacuolization were observed in the retinal tissue in the methanol group. These effects were not observed in the methanol + ILE and methanol + ILE +ethanol groups compared to the control group. Conclusion: The combination of methanol, ethanol, and ILE has a beneficial effect, especially on cardiac damage. Histopathologically, the combination of methanol + ethanol + ILE reduces the negative effects of methanol on the optic nerve and retina.

Background: Exposure to natural green environments has been associated with various physiological and psychological benefits, including potential improvements in visual acuity. This study investigates the molecular and visual effects of daily exposure to green landscapes among individuals with myopia in Parepare, Indonesia. Methods: A total of 250 participants with clinically diagnosed mild to moderate myopia were enrolled from January to December 2024. Participants underwent daily 2-hour exposure to green rice fields and were evaluated biweekly using standardized Snellen chart assessments over a 10-week period. Changes in visual acuity were tracked and statistically analyzed. Ethical clearance was obtained (EC/66891/01/2024). Results: Visual acuity improved significantly across the 10-week period. Biweekly assessments demonstrated a consistent improvement in uncorrected distance visual acuity, with a mean improvement of 0.2 logMAR by week 10. Molecularly, retinal tissue response to the green wavelength (495–570 nm) suggests reduced oxidative stress and increased dopamine activity, contributing to visual clarity. Conclusion: Daily exposure to natural green scenery can lead to measurable improvements in visual acuity, potentially via both ocular relaxation and molecular pathways involving dopamine signaling and oxidative stress reduction.

Mesenchymal stromal cells (MSCs) have emerged as a promising disease-modifying therapy for the complications of diabetes mellitus (DM), including diabetic retinopathy (DR). However, the optimal treatment regimen remains unclear, and challenges persist regarding the timing, route of delivery and the mechanisms underlying the therapeutic effects. This study focused on human umbilical cord-derived mesenchymal stromal cells (hUC-MSCs), to elucidate their retinal protective effects, and investigate the underlying mechanisms by which a single intravenous injection might ameliorate the pathological alterations of DR. Two time points after the development of DM were chosen for the in vivo experiments to study the effects of the intervention after different times of exposure to hyperglycemia. hUC-MSCs were injected via the tail vein at 8 and 16 weeks after STZ injection. Retinal samples were collected 2 weeks post-treatment to analyze the therapeutic effect of MSCs on DR. In vitro experiments were conducted using a Müller cell line and a retinal microvascular endothelial cell line cultured under high-glucose conditions, with treatment by hUC-MSCs conditioned media (MSC-CM), to explore the underlying mechanisms. After a single intravenous injection of hUC-MSCs at week 16 and not 8 weeks post-STZ injection, retinal tissue showed improved thickness of the inner nuclear layer. There was also an increase in the number of acellular capillaries observed in retinal flat mounts of diabetic animals which was improved in the DM and MSC treatment group. MSC treatment reduced high glucose induced activation markers (GFAP and Vimentin) of Müller cells and alleviated endoplasmic reticulum (ER) stress. VEGF expression was also reduced in the retina. MSC-conditioned media also reversed high glucose-induced expression of VEGF in Müller cells. Finally, in a retinal microvascular endothelial cell line, high glucose concentrations, demonstrated increased ER stress which was reduced by MSC conditioned media. Single Intravenous injection of hUC-MSC to DM animals could alleviate DR via reducing Müller cell and endothelial cell activation and ER stress, and thus might represent a promising therapy for DR.

The-state-of-the-art literature is eagerly searching for protective strategies of chemotherapy-induced retinal neurotoxicity, driven by oxidative stress, ER stress, mitochondrial dysfunction, and autophagy impairment. We investigated the neuroprotective effects of tempol, a stable nitroxide antioxidant, capable of crossing biological barriers and mitigating cisplatin-induced cytomolecular insult. Forty-eight Wistar rats were divided into control, cisplatin-treated, tempol-treated, and CIS + TEM-cotreated groups. Retinal tissues were analyzed through histological, immunohistochemical, and biomolecular oxidative profile and NGF expression techniques. Autophagy, ER stress markers, and ultrastructural changes were evaluated. Cisplatin induced severe retinal degeneration, characterized by photoreceptor disorganization, mitochondrial damage, impaired redox path-ways, impaired autophagy (LC3↓, p62↑), downregulated NGF, and ER stress activation (CHOP↑, JNK↑, XBP1↑, BiP↑). Tempol pre- and co-treatment restored the high baseline level of retinal autophagy as proved by immunohistochemical and mRNA upregulation of LC3 and downregulation of p62 in ganglion cell, inner nuclear, and outer nuclear layers as well as Beclin 1 gene expression restoration. Furthermore, tempol alleviated ER stress and preserved mitochondrial ultrastructure driven by NGF upregulation and restored redox sensitive pathways, leading to improved retinal ganglion and RPE cell architecture and neuroprotection. This study provides critical insights into the molecular mechanisms of cisplatin-induced retinopathy, emphasizing oxidative stress, ER stress, autophagy inhibition, and apoptosis. It highlights tempol's therapeutic potential as a neuroprotective agent targeting oxidative-apoptotic pathways and restoring ER-mitochondrial-autophagy-neurotrophic retinal homeostasis.

Type 2 diabetic (T2D) individuals are predisposed to enduring vascular complications despite therapeutic/lifestyle intervention due to 'metabolic memory', an epigenetic reprogramming in various cell/tissue types. The present study examined the potential role of DNMT isoforms in regulating glucose-induced metabolic memory and associated changes in endothelial metabolism leading to diabetic complications. The study involved micro/macro vascular endothelial cells (ECs), high-fat diet (HFD)-induced diabetic mouse models, and subjects with diabetic retinopathy (DR) at varying enforced levels of glycemia. Immunoblotting and HPLC-based analysis were performed to examine the expression of DNMT isoforms and global DNA methylation levels. Reactive oxygen species (ROS) and inflammatory mediators were analyzed by Spectramax and multiplex ELISA respectively. Cell cycle analysis and angiogenesis assays were performed by flowcytometry and 3D spheroid assays. Integrated omics analysis using LC-MS and RRBS was performed to identify metabolic and epigenomic signatures of metabolic memory. Candidate genes were validated in clinically characterized individuals with DR by RT-PCR. High glucose and AGEs persistently elevated expression of the DNMT1 but not DNMT3A and DNMT3B despite glucose normalization. Global DNA methylation, DNA synthesis, angiogenesis, oxidative stress, inflammatory mediators, and nucleotide metabolism intermediates were elevated and sustained despite glucose normalization. Metabolic memory was associated with differential methylation of genes associated with vascular functions and nucleotide metabolism. We observed persistent DNA methylation of IMPDH2, the rate-limiting enzyme of purine metabolism. DNMT1 and IMPDH2 were elevated in retinal and umbilical vein endothelial cells invitro, as well as retinal and aortic tissues of the HFD mice despite dietary intervention, which were reduced upon treatment with 5-aza-2'-deoxycytidine. IMPDH2 transcripts were elevated in subjects with DR undergoing antidiabetic therapy and in the exosomes derived from the vitreous of subjects with proliferative DR. Mycophenolate mofetil, a pharmacological inhibitor of IMPDH2, decreased sustained levels of DNMT1 and impeded sprout formation in 3D endothelial cultures induced by transient hyperglycemic conditions. Our study provides novel insights into the biology of metabolic memory by identifying IMPDH2 regulated by DNMT1 during epigenetic and metabolic reprogramming, with clinical relevance to the pathogenesis of DR.

Age-related macular degeneration (AMD) is a leading cause of central vision loss, and effective treatment options are limited once photoreceptors and the retinal pigment epithelium (RPE) are lost. In advanced stages, vision restoration requires strategies that replace or bypass degenerated retinal circuitry. Retinal sheet transplantation using fetal neural retinal tissue has emerged as a promising intervention, demonstrating long-term survival, integration with the host retina, and partial restoration of light-driven responses. We previously showed that such transplants can restore fundamental visual response properties in the primary visual cortex (V1) of rapidly degenerating rats. However, it remains unclear whether restored retinal input can support higher-order cortical computations that depend on the integration of classical and extra-classical receptive field mechanisms.In this study, we extend this investigation by evaluating whether fetal retinal sheet transplants can restore extra-classical surround modulation in neurons of higher visual areas (V2). Fetal retinal sheets (E18–E19) derived from donor rats were transplanted into one eye of Rho-S334ter line-3 rats at ages P41–P78, when rod degeneration is nearly complete and cones are largely nonfunctional. Animals were assessed 2.2–9.3 months post-surgery using in vivo extracellular single-unit recordings from V2, optokinetic testing, OCT imaging, and histology. Control groups included normal-vision rats, age-matched degenerated rats (AMC), and sham-operated line-3 rats.Transplants survived long term, developed laminated and rosetted photoreceptor structures, and integrated with the host retina. Optokinetic testing revealed significant improvement in spatial acuity in transplanted eyes compared with degenerated controls beginning at three months post-surgery. Transplanted rats exhibited a markedly higher proportion of visually responsive V2 neurons than degenerated animals (21.0% vs. 8.2%). They also showed significantly shorter response latencies and larger visually evoked response amplitudes, indicating improved transmission of retinal signals to the cortex.To quantify surround suppression, neurons were tested with sinusoidal gratings confined to the classical receptive field and gratings extended to full-field size. Transplanted rats displayed robust surround suppression properties similar to normal controls, including significantly reduced firing rates and narrower tuning under full-field conditions. A Support Vector Machine (SVM) classifier trained on net responses to CRF and FF stimulus sizes reliably distinguished control and transplanted neurons from degenerated ones but could not separate control from transplant, further indicating similar response properties in these two groups.These findings provide the first demonstration that retinal sheet transplants restore not only basic visual responses but also higher-order cortical mechanisms involving extra-classical surround suppression. This recovery of surround suppression in V2 suggests that transplanted retinal tissue can re-establish functionally meaningful circuits capable of supporting complex visual processing. The results underscore the therapeutic potential of retinal sheet transplantation for advanced retinal degenerative disease and provide the first evidence of surround suppression in the rat V2.

PurposeTo evaluate changes in retinal neurovascular and mitochondrial function after a 24-week yoga intervention in healthy older adults.MethodsThirty participants (mean age 72 ± 6 years; 25 females, 5 males) were randomized to either a cue-based yoga program (n = 15) or traditional Hatha yoga (n = 15), with 60-minute sessions three times per week for 24 weeks. Retinal assessments were conducted at baseline and follow-up. Optical coherence tomography angiography (OCTA) was used to evaluate retinal structure and vessel density. Retinal blood flow was measured with the Retinal Function Imager, and mitochondrial function was assessed via macular flavoprotein fluorescence using the OcuMet Beacon.ResultsSignificant increases were observed in retinal blood flow (2.21 to 2.72 nL/s, P = 0.002), capillary function (0.12 to 0.14 nL/s/mm, P = 0.004), and tissue perfusion (1.91 to 2.38 nL/s/mm³, P = 0.004). Macular flavoprotein fluorescence decreased (31.7 to 30.1 gsu, P = 0.041), suggesting improved mitochondrial function. No significant changes were found in vessel density, vessel length density, foveal avascular zone area, choriocapillaris density, or total retinal thickness. Between-group differences were mostly nonsignificant, except for baseline and change values in choriocapillaris density and change values in retinal thickness (P < 0.05).ConclusionsA 24-week yoga intervention was associated with improved retinal blood flow, capillary efficiency, and tissue perfusion in healthy older adults, with indications of enhanced mitochondrial function. These findings suggest yoga may support retinal vascular and metabolic health during aging.

Diabetic retinopathy is a common complication of diabetes mellitus that is characterised by neurovascular dysfunction and chronic inflammation. The stimulator of IFN genes (STING) signalling pathway plays a key role in inflammatory diseases. However, its cell-specific function and value as an early-intervention target for diabetic retinopathy remain unclear. We analysed public single-cell (sc)RNA-seq datasets from fibrous membranes of individuals with proliferative diabetic retinopathy and idiopathic macular hole, normal post-mortem retinas and retinal endothelial cells from diabetic and non-diabetic mice. A type 2 diabetes mouse model was established using a high-fat diet and streptozocin to assess STING localisation and expression differences. Using adeno-associated virus (serotype 2/1), siRNA or STING inhibitor H-151, we evaluated the effects of STING on inflammation and cell function both in vivo and in vitro. scRNA-seq analysis revealed increased STING expression and enriched IFN signalling in endothelial cells from samples of both humans and mice with diabetes. Our mouse model exhibited increased STING expression, along with its co-localisation with CD31, and upregulated IFNs in retinal tissues. Flow cytometry confirmed diabetes-induced endothelial cell-specific phosphorylation of TBK1, a downstream effector of STING. Genetic deletion or pharmacological inhibition of STING significantly ameliorated retinal inflammation and neurovascular dysfunction in diabetic mice. Our findings demonstrate endothelial-intrinsic activation of the cyclic GMP-AMP synthase (cGAS)/STING/IFN pathway as a key driver of retinal inflammation and neurovascular dysfunction in diabetes. Targeting this pathway may offer a potential therapeutic approach for early intervention in diabetic retinopathy.

To explore the methylation status of MSH6 in retinoblastoma (RB) and its impact on clinicopathological features and diagnosis. Differentially expressed genes were identified through bioinformatics screening of the GSE24673 and GSE125903 datasets, combined with GeneCards database analysis. A total of 102 RB patients and 62 trauma-enucleated controls between January 2018 and December 2023 were enrolled, with their clinicopathological data and retinal tissues collected. The mRNA and methylation levels of MSH6 in retinal tissues were detected using real-time quantitative polymerase chain reaction (PCR) and methylation-specific PCR. Western blot analysis was conducted in one pair of RB and control tissues for preliminary protein-level validation of MSH6 expression. Based on the methylation status of MSH6, RB patients were categorized into two groups: low-methylation and high-methylation. Both univariate and multivariate analyses were conducted to identify independent factors influencing the methylation levels using clinicopathological data. Receiver operating characteristic (ROC) curves were applied to evaluate the diagnostic potential of MSH6 methylation in RB. Bioinformatics analysis of public datasets revealed that MSH6 expression was downregulated across multiple cancers, RB. Consistently, in clinical RB tissues, MSH6 mRNA expression was significantly lower than that in control retinal tissues, whereas the promoter methylation level of MSH6 was markedly higher (both P<0.001), indicating that promoter hypermethylation may contribute to transcriptional silencing of MSH6 in RB. Patients with higher MSH6 methylation levels showed more advanced pathological classification and a higher frequency of metastasis. Multivariate logistic regression confirmed that metastatic status (P=0.008, OR=3.51) and pathological classification (P=0.005, OR=3.7) were independent factors associated with MSH6 methylation. Receiver operating characteristic (ROC) analysis demonstrated that MSH6 methylation could effectively distinguish RB tissues from non-tumorous controls (AUC=0.847, sensitivity=78.43%, specificity=80.65%), suggesting that MSH6 hypermethylation may serve as a potential diagnostic biomarker for RB. The methylation level of the MSH6 gene may be a key factor in RB pathogenesis. The methylation status of the MSH6 gene is closely associated with clinicopathological features and shows diagnostic potential.