Establishing chronic models of age-related macular degeneration via long-term iron ion overload.

Age-related macular degeneration (AMD) is characterized by the degenerative senescence in the retinal pigment epithelium (RPE) and photoreceptors, which is accompanied by the accumulation of iron ions in the aging retina. However, current models of acute oxidative stress are still insufficient to simulate the gradual progression of AMD. To address this, we established chronic injury models by exposing the aRPE-19 cells, 661W cells, and mouse retina to iron ion overload over time. Investigations at the levels of cell biology and molecular biology were performed. It was demonstrated that long-term treatment of excessive iron ions induced senescence-like morphological changes, decreased cell proliferation, and impaired mitochondrial function, contributing to apoptosis. Activation of the mitogen-activated protein kinase (MAPK) pathway and the downstream molecules were confirmed both in the aRPE-19 and 661W cells. Furthermore, iron ion overload resulted in dry AMD-like lesions and decreased visual function in the mouse retina. These findings suggest that chronic exposure to overloading iron ions plays a significant role in the pathogenesis of retinopathy and provide a potential model for future studies on AMD.NEW & NOTEWORTHY To explore the possibility of constructing reliable research carriers on age-related macular degeneration (AMD), iron ion overload was applied to establish models in vitro and in vivo. Subsequent investigations into cellular physiology and molecular biology confirmed the presence of senescence in these models. Through this study, we hope to provide a better option of feasible methods for future researches into AMD.

Precise prediction of size of a foldable capsular vitreous body via computerized three-dimensional ocular reconstruction in severe retinal detachment.

BACKGROUND: This study aimed to precisely predict the size and silicone oil injection of a foldable capsular vitreous body (FCVB) via computerized three-dimensional (3D) ocular reconstruction in the treatment of severe retinal detachment in China. METHODS: The 3D software Unigraphics NX was applied to determine the volume of the inner cavity with 16-30 mm axial length, assigning the anterior and posterior chambers, the FCVB sizes, and the silicone oil injection volume, and modeling the data between the axial length and the FCVB size. In clinical practice, IOL Master was applied to accurately measure the axial length of the contralateral healthy eye to anchor the anterior-posterior and horizontal diameters of the operated eye in horizontal position CT, and compared with the model to recommend the FCVB size and silicone oil amount, and the clinical effect was validated in cases across five hospitals in China. RESULTS: For the axial length of 16-30 mm, the volume of the inner cavity is 1.2 ml-8.4 ml. FCVB size and silicone oil volume were recommended based on this volume of the inner cavity. Of 253 cases, we noted 11 cases implanted with AV-10P and 1.05 ± 0.21 ml of silicone oil, 41 with AV-12P and 1.58 ± 0.18 ml of silicone oil, 163 with AV-13.5P and 2.48 ± 0.29 ml of silicone oil, 31 with AV-15P and 3.57 ± 0.39 ml of silicone oil, and 7 with AV-17P and 5.71 ± 0.81 ml of silicone oil. There was no significant difference in postoperative visual acuity scores compared with preoperative (P = 0.097), postoperative IOP(10.29 ± 0.57mmHg)was slightly higher than preoperative IOP (9.76 ± 0.48 mmHg), but there was still no statistically significant difference between the two comparisons (P = 0.405). CONCLUSION: Three-dimensional reconstruction prediction is a good solution for eyeballs with obvious individualized changes in severe retinal detachment, and this method helps doctors standardize FCVB size selection and the silicone oil amount for patients.

MAP4K4 is involved in the neuronal development of retinal photoreceptors.

Mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) is a potential regulator of photoreceptor development. To investigate the mechanisms underlying MAP4K4 during the neuronal development of retinal photoreceptors, we generated knockout models of C57BL/6j mice in vivo and 661 W cells in vitro. Our findings revealed homozygous lethality and neural tube malformation in mice subjected to Map4k4 DNA ablation, providing evidence for the involvement of MAP4K4 in early stage embryonic neural formation. Furthermore, our study demonstrated that the ablation of Map4k4 DNA led to the vulnerability of photoreceptor neurites during induced neuronal development. By monitoring transcriptional and protein variations in mitogen-activated protein kinase (MAPK) signaling pathway-related factors, we discovered an imbalance in neurogenesis-related factors in Map4k4 -/- cells. Specifically, MAP4K4 promotes jun proto-oncogene (c-JUN) phosphorylation and recruits other factors related to nerve growth, ultimately leading to the robust formation of photoreceptor neurites. These data suggest that MAP4K4 plays a decisive role in regulating the fate of retinal photoreceptors through molecular modulation and contributes to our understanding of vision formation.

Oxidative stress-induced lncRNA CYLD-AS1 promotes RPE inflammation via Nrf2/miR-134-5p/NF-κB signaling pathway.

Oxidative stress-induced damage to and dysfunction of retinal pigment epithelium (RPE) cells are important pathogenetic factors of age-related macular degeneration (AMD); however, the underlying molecular mechanism is not fully understood. Long noncoding RNAs (lncRNAs) have important roles in various biological processes. In this study, using an oxidative damage model in RPE cells, we identified a novel oxidation-related lncRNA named CYLD-AS1. We further revealed that the expression of CYLD-AS1 was increased in RPEs during oxidative stress. Depletion of CYLD-AS1 promoted cell proliferation and mitochondrial function and protected RPE cells against hydrogen peroxide (H2 O2 )-induced damage. Mechanistically, CYLD-AS1 also regulated the expression of NRF2, which is related to oxidative stress, and NF-κB signaling pathway members, which are related to inflammation. Remarkably, these two signaling pathways were mediated by the CYLD-AS1 interactor miR-134-5p. Moreover, exosomes secreted by CYLD-AS1 knockdown RPE cells had a lower proinflammatory effect than those secreted by control cells. In summary, our study revealed that CYLD-AS1 affects the oxidative stress-related and inflammatory functions of RPE cells by sponging miR-134-5p to mediate NRF2/NF-κB signaling pathway activity, suggesting that targeting CYLD-AS1 could be a promising strategy for the treatment of AMD and related diseases.

METTL3 attenuates proliferative vitreoretinopathy and epithelial-mesenchymal transition of retinal pigment epithelial cells via wnt/ß-catenin pathway.

Proliferative vitreoretinopathy (PVR) is a refractory vitreoretinal fibrosis disease, and epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells is the key pathological mechanism of PVR. However, few studies focused on the role of METTL3, the dominating methyltransferase for m6A RNA modification in PVR pathogenesis. Immunofluorescence staining and qRT-PCR were used to determine the expression of METTL3 in human tissues. Lentiviral transfection was used to stably overexpress and knockdown METTL3 in ARPE-19 cells. MTT assay was employed to study the effects of METTL3 on cell proliferation. The impact of METTL3 on the EMT of ARPE-19 cells was assessed by migratory assay, morphological observation and expression of EMT markers. Intravitreal injection of cells overexpressing METTL3 was used to assess the impact of METTL3 on the establishment of the PVR model. We found that METTL3 expression was less in human PVR membranes than in the normal RPE layers. In ARPE-19 cells, total m6A abundance and the METTL3 expression were down-regulated after EMT. Additionally, METTL3 overexpression inhibited cell proliferation through inducing cell cycle arrest at G0/G1 phase. Furthermore, METTL3 overexpression weakened the capacity of TGFß1 to trigger EMT by regulating wnt/ß -catenin pathway. Oppositely, knockdown of METTL3 facilitated proliferation and EMT of ARPE-19 cells. In vivo, intravitreal injection of METTL3-overexpressing cells delayed the development of PVR compared with injection of control cells. In summary, this study suggested that METTL3 is involved in the PVR process, and METTL3 overexpression inhibits the EMT of ARPE-19 cells in vitro and suppresses the PVR process in vivo.

Risk Factors and Prognosis of Pediatric Open Globe Injuries without Initial Light Perception.

PURPOSE: The aim of this study was to investigate the possible risk factors and prognosis of initial no light perception (NLP) in pediatric open globe injuries (POGI). PROCEDURES: This retrospective, comparative, interventional case-control study included 865 eyes of POGI patients presenting to a tertiary referral ophthalmic center from January 1, 2011 to December 31, 2015. Eyes were divided into 2 groups: the NLP group included eyes with initial NLP, and the light perception (LP) group included eyes with initial LP or vision better than LP. RESULTS: The following risk factors were significantly related to initial NLP: severe intraocular hemorrhage (OR 3.287, p = 0.015), retinal detachment (RD; OR 2.527, p = 0.007), choroidal damage (OR 2.680, p = 0.016), and endophthalmitis (OR 4.221, p < 0.001). Choroidal damage is related to remaining NLP after vitreoretinal surgery (OR 12.384, p = 0.003). At the last visit, more eyes in the NLP group suffered from silicone oil-sustained status (OR 0.266, p = 0.020) or ocular atrophy (OR 0.640, p = 0.004), and fewer eyes benefitted from final LP (OR 41.061, p < 0.001) and anatomic success (OR 4.515, p < 0.001). CONCLUSION: Severe intraocular hemorrhage, RD, choroidal damage, and endophthalmitis were possible predictors of initial NLP in POGI. Choroidal damage was the major factor related to an NLP prognosis. Traumatized eyes with initial NLP could be anatomically and functionally preserved by vitreoretinal surgery.

m6A methyltransferase METTL3 promotes retinoblastoma progression via PI3K/AKT/mTOR pathway.

Retinoblastoma (RB) is a common intraocular malignancy in children. Due to the poor prognosis of RB, it is crucial to search for efficient diagnostic and therapeutic strategies. Studies have shown that methyltransferase-like 3 (METTL3), a major RNA N (6)-adenosine methyltransferase, is closely related to the initiation and development of cancers. Nevertheless, whether METTL3 is associated with RB remains unexplored. Therefore, we investigated the function and mechanisms of METTL3 in the regulation of RB progression. We manipulated METTL3 expression in RB cells. Then, cell proliferation, apoptosis, migration and invasion were analysed. We also analysed the expression of PI3K/AKT/mTOR pathway members. Finally, we incorporated subcutaneous xenograft mouse models into our studies. The results showed that METTL3 is highly expressed in RB patients and RB cells. We found that METTL3 knockdown decreases cell proliferation, migration and invasion of RB cells, while METTL3 overexpression promotes RB progression in vitro and in vivo. Moreover, two downstream members of the PI3K/AKT/mTOR pathway, P70S6K and 4EBP1, were affected by METTL3. Our study revealed that METTL3 promotes the progression of RB through PI3K/AKT/mTOR pathways in vitro and in vivo. Targeting the METTL3/PI3K/AKT/mTOR signalling axis could be a promising therapeutic strategy for the treatment of RB.

ID2 protects retinal pigment epithelium cells from oxidative damage through p-ERK1/2/ID2/NRF2.

Age-related macular degeneration (AMD) is the leading cause of blindness during aging. The degeneration of retinal pigment epithelium (RPE) is the main pathologic characteristic of AMD. ID2 is a member of the Inhibitor of DNA binding proteins (ID) family and is involved in regulation of cell proliferation and differentiation. However, currently the role of ID2 in oxidative injury response in RPE cells remains unknown. Here we showed that oxidative stress increased ID2 expression in RPE cells. Knockdown of ID2 promoted cell apoptosis and increased ROS level in RPE cells that were subjected to oxidative damage. In addition, over-expression of ID2 attenuated the oxidative damage response in RPE cells. Mechanistically, ID2 protected RPE cells from oxidative damage through activating NRF2. Furthermore, phosphorylation of ERK1/2 positively regulated the protective function of ID2. Finally, we confirmed that the oxidative damage increased Id2 expression and over-expression of Id2 elevated Nrf2 expression in primary mouse RPE cells. Therefore, ID2 protects RPE cells from oxidative damage through the p-ERK1/2/ID2/NRF2 pathway. Our study contributes to a better understanding of the mechanisms underlying oxidative stress in AMD and may present a new strategy for AMD treatment.

Modified technique for transscleral fixation of posterior chamber intraocular lenses.

BACKGROUND: Suture exposure remains to be a potential problem of transscleral fixated posterior chamber intraocular lens (PCIOL). We report a modified technique to minimize the risk of suture exposure for the transscleral fixation of PCIOL. METHODS: The modified surgical technique is as following: at first, two 3 mm × 4 mm square scleral pockets were created from groove incisions at opposite positions. A straight needle attached to a 10-0 polypropylene suture was passed through one incision groove. Then, a 27-Gauge hollow needle passed through the opposite sclera incision bed was used to retrieve the straight fine needle via its barrel. The sutures were tied to themselves after one more bite on the scleral bed. At last, the suture ends were left long (about 4 mm) and laid flat into corresponding laminar scleral pockets. This modified technique of PCIOL was performed in 48 post-traumatic aphakic vitrectomized eyes from 48 patients (47 male, one female) with mean age of 34.8 ± 14.8 years. Main outcome measures included best corrective visual acuity (BCVA), IOL decentration, IOL tilt, and postoperative complications. RESULTS: The mean follow-up was 32.3 ± 10.8 months (3-67 months). The LogMAR BCVA remained stable, from a preoperative value of 0.46 ± 0.34 to postoperative 0.44 ± 0.34 (p = 0.69). Mild IOL tilt (5-10°) was observed in five eyes, and slight IOL decentration (0.5-1.0 mm) was seen in three cases. No case of suture exposure, suture breakage, IOL dislocation, or endophthalmitis was observed during the follow up period. CONCLUSION: The modified technique allowed stable placement of PCIOLs in post-traumatic aphakic eyes with a wide range of follow-up. Our procedure might have the potential benefit to avoid suture exposure in scleral-fixated IOL implantation.

Causative organisms of post-traumatic endophthalmitis: a 20-year retrospective study.

BACKGROUND: A wide range of organisms that enter the eye following ocular trauma can cause endophthalmitis. This study was to investigate the spectrum of pathogens and antibiotic susceptibility of bacterial isolates from a large cohort of post-traumatic endophthalmitis cases. METHODS: A retrospective study of 912 post-traumatic endophthalmitis patients treated at a tertiary eye-care center in China was performed. The associations between risk factors and the most common isolated organisms were investigated by Chi square Test. The percent susceptibilities for the first 10 years (1990-1999) and the second 10 years (2000-2009) were compared by Chi square test. p < 0.05 was considered statistically significant. RESULTS: Three-hundred-forty-seven (38.1%) cases of endophthalmitis were culture-positive, and 11 (3.2%) showed mixed infections (Gram-negative bacilli and fungi), yielding a total of 358 microbial pathogens. Culture proven organisms included 150 (41.9%) Gram-positive cocci, 104 (29.1%) Gram-negative bacilli, 44 (12.3%) Gram-positive bacilli, and 60 (16.8%) fungi. The coagulase-negative staphylococcal (CNS) species S. epidermidis (21.8%) and S. saprophyticus (12.0%) were the predominant pathogens, followed by Bacillus subtilis (8.7%), Pseudomonas aeruginosa (7.8%), and Escherichia coli (6.4%). Delayed repair over 24 h (p < 0.001) and metallic injury (p < 0.01) were significantly associated with positive culture of CNS. The most frequent fungal species were Aspergillus (26/60), followed by yeast-like fungi (18/60). P. aeruginosa was relatively sensitive to ciprofloxacin (83.3%), cefoperazone (75%), tobramycin (75%), cefuroxime (75%), and ceftazidime (75%) during the second decade. Multi-drug resistance was observed in the predominant Gram-negative bacteria. CONCLUSION: We identified a broad spectrum of microbes causing post-traumatic endophthalmitis, with Gram-positive cocci the most frequently identified causative organism, followed by Bacillus species, fungi, and mixed infections. CNS infection was statistically associated with delayed repair and metallic injury. Variation in antibiotic susceptibility was observed among isolated bacteria and between different periods. Ciprofloxacin and ceftazidime in the first and second decades of the study, respectively, showed the highest activity against bacterial post-traumatic endophthalmitis. For infections caused by P. aeruginosa, a combination therapy of ciprofloxacin, tobramycin, and one of the cephalosporins might provide optimal coverage according to data from the second decade.

Lens Displacement and Retinal Injury in Blunt Eye Trauma.

Introduction: We aimed to investigate the incidence and prognosis of retinal injury in patients with lens dislocation caused by blunt eye trauma. Methods: We retrospectively analyzed 53 patients who underwent lensectomy and vitrectomy for contusive lens dislocation and had no preoperative retinal injuries. Patients were categorized according to the presence of retinal injury discovered intraoperatively. The clinical features of 53 eyes were assessed during a 3-month postoperative follow-up. Results: Retinal injuries were observed intraoperatively in 28 patients (52.8%), predominantly in peripheral regions, with a single retinal tear being the most common type. Total lens dislocation was more frequent than subluxation in the group with retinal injuries. The intraocular pressure (IOP) at the 3-month follow-up was significantly lower than the initial IOP in both groups, with no significant differences between them. The corrected distance visual acuity (CDVA) significantly improved in both groups without significant differences. Conclusion: Half of the patients without preoperative retinal injuries were found to have injuries during surgery. Total lens dislocation carried a greater risk of retinal injuries than subluxation. The improvement in CDVA after prompt retinal injury treatment did not significantly differ from that in patients without retinal injury, highlighting the importance of prompt intervention.

Blockage of Notch signaling inhibits the migration and proliferation of retinal pigment epithelial cells.

The Notch signaling is an evolutionarily conserved cell-cell communication pathway that plays critical roles in the proliferation, survival, apoptosis, and fate determination of mammalian cells. Retinal pigment epithelial (RPE) cells are responsible for supporting the function of the neural retina and maintaining vision. This study investigated the function of Notch signaling in RPE cells. We found that the members of the Notch signaling pathway components were differentially expressed in RPE cells. Furthermore, blockage of Notch signaling inhibited the migration and proliferation of RPE cells and reduced the expression levels of certain Notch signaling target genes, including HES1, MYC, HEY2, and SOX9. Our data reveal a critical role of Notch signaling in RPE cells, suggesting that targeting Notch signaling may provide a novel approach for the treatment of ophthalmic diseases related to RPE cells.

Protective effect of ginsenoside Rg1 on 661W cells exposed to oxygen-glucose deprivation/reperfusion via keap1/nrf2 pathway.

AIM: To construct an in vitro model of oxygen-glucose deprivation/reperfusion (OGD/R) induced injury to the optic nerve and to study the oxidative damage mechanism of ischemia-reperfusion (I/R) injury in 661W cells and the protective effect of ginsenoside Rg1. METHODS: The 661W cells were treated with different concentrations of Na2S2O4 to establish OGD/R model in vitro. Apoptosis, intracellular reactive oxygen species (ROS) levels and superoxide dismutase (SOD) levels were measured at different time points during the reperfusion injury process. The injury model was pretreated with graded concentrations of ginsenoside Rg1. Real-time polymerase chain reaction (PCR) was used to measure the expression levels of cytochrome C (cyt C)/B-cell lymphoma-2 (Bcl2)/Bcl2 associated protein X (Bax), heme oxygenase-1 (HO-1), caspase9, nuclear factor erythroid 2-related factor 2 (nrf2), kelch-like ECH-associated protein 1 (keap1) and other genes. Western blot was used to detect the expression of nrf2, phosphorylated nrf2 (pnrf2) and keap1 protein levels. RESULTS: Compared to the untreated group, the cell activity of 661W cells treated with Na2S2O4 for 6 and 8h decreased (P<0.01). Additionally, the ROS content increased and SOD levels decreased significantly (P<0.01). In contrast, treatment with ginsenoside Rg1 reversed the cell viability and SOD levels in comparison to the Na2S2O4 treated group (P<0.01). Moreover, Rg1 reduced the levels of caspase3, caspase9, and cytC, while increasing the Bcl2/Bax level. These differences were all statistically significant (P<0.05). Western blot analysis showed no significant difference in the protein expression levels of keap1 and nrf2 with Rg1 treatment, however, Rg1 significantly increased the ratio of pnrf2/nrf2 protein expression compared to the Na2S2O4 treated group (P<0.001). CONCLUSION: The OGD/R process is induced in 661W cells using Na2S2O4. Rg1 inhibits OGD/R-induced oxidative damage and alleviates the extent of apoptosis in 661W cells through the keap1/nrf2 pathway. These results suggest a potential protective effect of Rg1 against retinal I/R injury.

Silibinin Prevents TGFß-Induced EMT of RPE in Proliferative Vitreoretinopathy by Inhibiting Stat3 and Smad3 Phosphorylation.

Purpose: The purpose of this study was to investigate the effects of silibinin on epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) and proliferative vitreoretinopathy (PVR) formation, as well as its underlying molecular mechanism. Methods: Cellular morphological change and EMT molecular markers were evaluated by using phase contrast imaging, qPCR, and Western blot (WB) to investigate the impact of silibinin on the EMT of ARPE-19 cells. Scratch assay and transwell assay were used to study the effect of silibinin on cell migration. An intravitreally injected RPE-induced rat PVR model was used to assess the effect of silibinin on PVR in vivo. RNA-seq was applied to study the molecular mechanism of silibinin-mediated PVR prevention. Results: Silibinin inhibited TGFß1-induced EMT and migration of RPE in a dose-dependent manner in vitro. Moreover, silibinin prevented proliferative membrane formation in an intravitreal injected RPE-induced rat PVR model. In line with these findings, RNA-seq revealed a global suppression of TGFß1-induced EMT and migration-related genes by silibinin in RPEs. Mechanistically, silibinin reduced TGFß1-induced phosphorylation levels of Smad3 and Stat3, and Smad3 nuclear translocation in RPE. Conclusions: Silibinin inhibits the EMT of RPE cells in vitro and prevents the formation of PVR membranes in vivo. Mechanistically, silibinin inhibits Smad3 phosphorylation and suppresses Smad3 nuclear translocation through the inhibition of Stat3 phosphorylation. These findings suggest that silibinin may serve as a potential treatment for PVR.

Preliminary efficacy and safety of a silicone oil-filled foldable capsular vitreous body in the treatment of severe retinal detachment.

PURPOSE: We previously invented a novel foldable capsular vitreous body (FCVB) in the treatment of severe retinal detachment. The purpose of this study was to determine its hydrolytic stability in vitro and further evaluate its efficacy and safety in human eyes. METHODS: The hydrolytic stability test proceeded according to State Food and Drug Administration guidelines about intraocular lenses of the ophthalmic implants. A standard three-port pars plana vitrectomy was performed, and FCVB was triple folded and sent into the vitreous cavity of three eyes; then silicone oil was injected into the capsule to support the retina. The treated eyes were examined using Goldmann applanation tonometry, fundus photography, optical coherence tomography, noncontact specular microscopy, and ultrasound biomicroscopy during a 12-month follow-up appointment. RESULTS: The mass of FCVB with silicone oil after 60-day accelerating aging temperature was equal to that at baseline. The FCVB can easily be implanted into the vitreous cavity through a 3-mm incision. The visual acuity and intraocular pressure after FCVB implantation show a slight elevation compared with those of preoperative eyes. The fundus and optical coherence tomography showed that the FCVB was well distributed in the vitreous cavity and evenly supported the retina. Retinal reattachment was found in 3 eyes at the 12-month examination. There was no statistically significant decrease in the density of corneal endothelial cells from baseline to 12 months after FCVB implantation. Ultrasound biomicroscopy showed that the FCVB smoothly contacted but not crushed the ciliary body. CONCLUSION: Silicone oil-filled FCVB was shown to be effective and safe in 3 eyes as a vitreous substitute over a 12-month observation time.

Clinical Features of Endogenous Endophthalmitis Secondary to Minimally Invasive Upper Urinary Tract Calculus Removal.

PURPOSE: To evaluate endogenous endophthalmitis clinical features following minimally invasive removal of upper urinary tract calculi. METHODS: Medical records of twelve patients (17 eyes) with endogenous endophthalmitis secondary to minimally invasive upper urinary tract calculus removal were retrospectively reviewed. RESULTS: Diabetes mellitus was found in 7 patients (58%). 10 patients (83%) suffered from fever. The stone extraction and ocular symptom onset interval ranged from 2 to 22 days. All eyes presented as vitritis and fluffy yellow-white retinal exudates. Hypopyon was only found in 3 eyes (18%). 5 patients (42%) were misdiagnosed as uveitis which led to mismanagement. Ocular fluids were culture positive for only C. albicans in 12 eyes (71%). 10 of 12 eyes (83%) with silicon oil tamponade obtained a final BCVA≥0.05. CONCLUSIONS: C. albicans was the most common endogenous endophthalmitis pathogen after urinary calculus removal by minimally invasive surgery. Pars plana vitrectomy with silicon oil tamponade may be helpful to achieve a favorable visual outcome. Routine ophthalmologic evaluation by the uveitis or vitreoretinal specialist may be necessary within 2 weeks after the urological procedures.

Primary Vitreoretinal Lymphoma: A Retrospective Study of 20 Eyes.

Purpose: This study aimed to describe and analyze the clinical features of 20 eyes of 15 primary vitreoretinal lymphoma (PVRL) patients. Methods: This was a retrospective case series and a review of the literature. Fifteen PVRL patients (20 affected eyes) referred between February 2011 and December 2019 were recruited, and their medical records were retrospectively reviewed. Results: Among these 15 PVRL patients, seven were men (46.67%), and five had bilateral PVRL (33.33%). The median onset age was 66 ± 9.26 years and six (40%) patients had central nervous system (CNS) involvement, and two of them died of CNS-related complications. The ocular symptoms varied from decreased vision to binocular diplopia. The ocular manifestations were diverse and involved both the anterior and posterior segments, including the vitreous cells, subretinal white-yellow lesions, cotton-wool spots, and ophthalmoplegia. The rate of misdiagnosis and failure to diagnose was 100%, and 30% of them were misdiagnosed as uveitis. We found five cases revealing rare characteristics of this malignancy. Among them, there were two cases with mild hypertensive retinopathy exhibiting cotton-wool spots, one case mimicking age-related macular degeneration (AMD), one case with systemic lupus erythematosus (SLE), and one patient had extraocular muscle involvement. To the best of our knowledge, we reported PVRL exhibiting cotton-wool spots as the main manifestation and coexisting with extraocular myopathy for the first time. Conclusions: PVRL is a rare intraocular malignancy that commonly masquerades as uveitis. As the clinical signs and symptoms are atypical, ophthalmologists must carefully examine patients to avoid misdiagnosis or a failure to diagnose. Cotton-wool spots and extraocular myopathy might be the dominant initial symptoms in PVRL patients, and AMD should be considered a differential diagnosis of PVRL. SLE patients under immunosuppressive treatment could have spontaneous PVRL.

Arbutin Protects Retinal Pigment Epithelium Against Oxidative Stress by Modulating SIRT1/FOXO3a/PGC-1α/ß Pathway.

Age-related macular degeneration (AMD), which is the leading cause of blindness among the elderly in western societies, is majorly accompanied by retinal pigment epithelium (RPE) degeneration. Because of the irreversible RPE cell loss among oxidative stress, it is crucial to search for available drugs for atrophic (dry) AMD. RNA-Seq analysis revealed that genes related to aging and mitochondrial health were differentially expressed under Arbutin treatment, whereas compared to oxidative injury, our study demonstrated that Arbutin substantially abrogated oxidative stress-induced cell senescence and apoptosis linked to intracellular antioxidant enzyme system homeostasis maintenance, restored mitochondrial membrane potential (MMP), and reduced the SA-ß-GAL accumulation in RPE. Furthermore, Arbutin alleviated oxidative stress-mediated cell apoptosis and senescence via activation of SIRT1, as evidenced by the increase of the downstream FoxO3a and PGC-1α/ß that are related to mitochondrial biogenesis, and the suppression of NF-κB p65 inflammasome, whereas rehabilitation of oxidative stress by SIRT1 inhibitor attenuated the protective effect of Arbutin. In conclusion, we validated the results in an in vivo model constructed by NAIO3-injured mice. OCT and HE staining showed that Arbutin sustained retinal integrity in the case of oxidative damage in vivo, and the disorder of RPE cytochrome was alleviated through fundus observation. In summary, our findings identified that oxidative stress-induced mitochondrial malfunction and the subsequent senescence acceleration in RPE cells, whereas Arbutin inhibited TBHP-induced RPE degeneration via regulating the SIRT1/Foxo3a/PGC-1α/ß signaling pathway. These findings suggested that Arbutin is a new agent with potential applications in the development of AMD diseases.

Maintaining blood retinal barrier homeostasis to attenuate retinal ischemia-reperfusion injury by targeting the KEAP1/NRF2/ARE pathway with lycopene.

Retinal ischemia-reperfusion (I/R) often results in intractable visual impairments, where blood retinal barrier (BRB) homeostasis mediated by retinal pigment epithelium (RPE) and retinal microvascular endothelium (RME) is crucial. However, strategies targeting the BRB are limited. Thus, we investigated the inconclusive effect of lycopene (LYC) in retinal protection under I/R. LYC elevated cellular viability and reversed oxidative stress in aRPE-19 cells/hRME cells under I/R conditions based on oxygen-glucose deprivation (OGD) in vitro. Molecular analysis showed that LYC promoted NRF2 expression and enhanced the downstream factors of the KEAP1/NRF2/ARE pathway: LYC increased the activities of antioxidants, including SOD and CAT, whereas it enhanced the mRNA expression of HO-1 (ho-1) and NQO-1 (nqo-1). The activation resulted in restrained ROS and MDA. On the other hand, LYC ameliorated the damage to retinal function and morphology in a mouse I/R model, which was established by unilateral ligation of the left pterygopalatine artery/external carotid artery and reperfusion. LYC promoted the expression of NRF2 in both the neural retina and the RPE choroid in vivo. This evidence revealed the potential of LYC in retinal protection under I/R, uncovering the pharmacological effect of the KEAP1/NRF2/ARE pathway in BRB targeting. The study generates new insights into scientific practices in retinal research.

2,3,5,6-Tetramethylpyrazine protects retinal photoreceptors against endoplasmic reticulum stress by modulating ATF4-mediated inhibition of PRP aggregation.

Endoplasmic reticulum (ER) stress is a common threat to photoreceptors during the pathogenesis of chronic retinopathies and often results in irreversible visual impairment. 2,3,5,6-Tetramethylpyrazine (TMP), which possesses many beneficial pharmacological activities, is a potential drug that could be used to protect photoreceptors. In the present study, we found that the cellular growth rate of 661 W cells cultured under low glucose conditions was lower than that of control cells, while the G2/M phase of the cell cycle was longer. We further found that the mitochondrial membrane potential (ΔΨm) was lower and that ER stress factor expression was increased in 661 W cells cultured under low glucose conditions. TMP reversed these trends. Visual function and cell counts in the outer nuclear layer (ONL) were low and the TUNEL-positive rate in the ONL was high in a C3H mouse model of spontaneous retinal degeneration. Similarly, visual function was decreased, and the TUNEL-positive rate in the ONL was increased in fasted C57/BL6j mice compared with control mice. On the other hand, ER stress factor expression was found to be increased in the retinas of both mouse models, as shown by reverse transcription real-time PCR (RT-qPCR) and western blotting. TMP reversed the physiological and molecular biological variations observed in both mouse models, and ATF4 expression was enhanced again. Further investigation by using western blotting illustrated that the proportion of insoluble prion protein (PRP) versus soluble PRP was reduced both in vitro and in vivo. Taken together, these results suggest that TMP increased the functions of photoreceptors by alleviating ER stress in vitro and in vivo, and the intrinsic mechanism was the ATF4-mediated inhibition of PRP aggregation. TMP may potentially be used clinically as a therapeutic agent to attenuate the functional loss of photoreceptors during the pathogenesis of chronic retinopathies. KEY MESSAGES: • Already known: TMP is a beneficial drug mainly used in clinic to enhance organ functions, and the intrinsic mechanism is still worthy of exploring. • New in the study: We discovered that TMP ameliorated retinal photoreceptors function via ER stress alleviation, which was promoted by ATF4-mediated inhibition of PRP aggregation. • Application prospect: In prospective clinical practices, TMP may potentially be used in the clinic as a therapeutic agent to attenuate the photoreceptors functional reduction in chronic retinopathies.