Assessment and management of retinopathy of prematurity in the era of anti-vascular endothelial growth factor (VEGF)

Erianin inhibits cell migration and induces apoptosis by inhibiting VEGF-α/PI3K/AKT signaling pathway in malignant melanoma

Erianin, extracted from Dendrobium chrysotoxum Lindl, has shown significant antitumour activity in various cancers, including bladder, cervical, and nasopharyngeal carcinoma. This study explores Erianin's impact on melanoma, a prevalent intraocular malignancy in adults, emphasizing cell growth inhibition and its mechanism. Vascular endothelial growth factor-α (VEGF-α), a validated therapeutic target in uveal melanoma angiogenesis, was considered. Despite its origin from Dendrobium plants in the Orchidaceae family, Erianin's anti-melanoma effects and its potential to inhibit the PI3K/AKT/mTOR signalling pathway to decrease VEGF-α secretion in melanoma cells remain unexplored. Thus, Erianin's effects on A375 cells and its underlying molecular mechanisms were investigated. Erianin induced apoptosis in A375 cells, as demonstrated by flow cytometry and western blot assays. Additionally, Erianin inhibited A375 cell migration, proliferation, and invasion in vitro, evidenced by cell scratch, EdU stain, and transwell cell invasion assays. Mechanistically, Erianin downregulated VEGF-α and VEGF Receptor 2 expression while inhibiting PI3K/AKT pathway activation, indicated by western blot and immunofluorescence analyses. Furthermore, both western blot and immunofluorescence analyses confirmed Erianin's regulation of VEGF-α and VEGFR2 expression. This study suggests that Erianin is a novel compound capable of inducing cell apoptosis while suppressing the activation of the VEGF/PI3K/AKT signalling pathway in A375 cells, thereby inhibiting cell proliferation.

Targeting mitochondrial DNA-STING-NF-κB Axis-mediated microglia activation by cryptotanshinone alleviates ischemic retinopathy

BACKGROUND

Ischemic retinopathy, a leading cause of vision impairment, involves oxidative stress and dysregulated inflammation, with microglia playing a key role. Cryptotanshinone (CTS), a bioactive compound from Salvia miltiorrhiza, exhibits anti-inflammatory and antioxidant properties and thus has the potential for development as a therapeutic agent. However, the actual mechanism of action of CTS in ischemic retinopathy is not known. Overactivation of the STING pathway in microglia is critical in ischemic retinopathy pathogenesis and a potential target of CTS.

PURPOSE

This study aimed to explore whether CTS alleviates ischemic retinopathy by modulating microglial STING signaling.

METHODS

Oxygen-induced retinopathy (OIR) mice and hypoxia-induced microglial cells were used. CTS efficacy in ischemic retinopathy was evaluated at multiple stages using fluorescein fundus angiography, electroretinogram, H&E staining, and Western blotting of relevant proteins. Network pharmacology and RNA sequencing identified STING as a key target. Furthermore, surface plasmon resonance (SPR), molecular docking, and site-directed mutagenesis were systematically employed to elucidate the precise binding interface between CTS and the STING protein. STING activation and knockout models were employed to further investigate the mechanisms of action of CTS.

RESULTS

CTS treatment reduced microglial activation and pathological retinal angiogenesis, and protected both retinal function and structure in OIR mice. Network pharmacology, RNA sequencing, and experimental validation demonstrated a significant link between the protective effect of CTS and the inhibition of STING signaling. Mechanistically, CTS suppressed cytosolic mtDNA release, blocked STING translocation from the ER to the Golgi, and enhanced lysosomal STING degradation. These CTS-mediated effects were abolished by STING activation and absent in Sting-deficient OIR mice. Notably, CTS combined with anti-VEGF therapy showed synergistic efficacy in suppressing pathological retinal neovascularization.

CONCLUSION

CTS, a natural inhibitor of STING, alleviated ischemic retinopathy by inhibiting the mtDNA-STING-NF-κB signaling pathway via multifaceted mechanisms in microglia.

Persistent avascular retina in retinopathy of prematurity

Persistent avascular retina (PAR) has been increasingly reported with the increased use of anti-vascular endothelial growth factor (VEGF) agents in treatment-requiring ROP. However, they have also been observed in ROP eyes that did not meet treatment requirement and spontaneously regressed. PAR is highlighted in the updated nomenclature under the International Classification of Retinopathy of Prematurity, 3rd edition (ICROP3) consensus statement, underscoring the increased emphasis in detecting PAR. PAR has been noted to persist beyond existing ROP screening guidelines, and were found to be associated with complications like retinal tear and detachment, especially in eyes with more posterior PAR. Thus, serial monitoring of retinal vascularization, facilitated by fluorescein angiography and wide-field imaging, for these associated complications have been encouraged. The current lack of consensus in the follow-up and management of PAR prompts further work in this area: understanding the natural course of retinal vascularization in both untreated and treated ROP, the modulation of anti-VEGF on retinal function, and the clinical significance of PAR-associated vascular patterns can help to guide management protocols for PAR in ROP eyes.

LncRNA MALAT1's role in the development of retinopathy: A review

Long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and retinopathy are 2 distinct yet interconnected areas of research in the field of ocular studies. MALAT1, with its diverse biological functions, has been extensively studied and demonstrated to play a role in various diseases, including ocular pathologies. Its involvement in alternative splicing regulation, transcriptional control, and the competing endogenous RNA (ceRNA) network suggests its potential implication in retinopathy. Retinopathy refers to a group of disorders that affect the retina, leading to vision impairment and, in severe cases, even blindness. These conditions include diabetic retinopathy, retinoblastoma, proliferative vitreoretinopathy, retinopathy of prematurity, and retinal neurodegeneration. The understanding of the molecular mechanisms underlying the development and progression of retinopathy, along with the potential involvement of MALAT1, can provide valuable insights for the diagnosis and treatment of this condition. Retinopathy, characterized by various manifestations and underlying mechanisms, presents a significant challenge in the field of ophthalmology. As a complex disease, its pathogenesis involves multifactorial factors, including angiogenic dysregulation, inflammatory responses, oxidative stress, and cellular signaling abnormalities. The emerging role of long noncoding RNA MALAT1 in retinopathy has attracted considerable attention. MALAT1 has been found to participate in multiple cellular processes, including alternative splicing regulation and transcriptional control. Additionally, the competing endogenous RNA (ceRNA) network involving MALAT1 indicates its potential relevance as a regulator in retinopathy. Further investigations into the specific mechanisms underlying MALAT1's involvement in retinopathy pathogenesis may provide valuable insights into the development of diagnostic and therapeutic approaches for managing retinal disorders.

Biglycan stimulates retinal pathological angiogenesis via up-regulation of CXCL12 expression in pericytes

Retinal pathological angiogenesis (PA) is a common hallmark in proliferative retinopathies, including age-related macular degeneration (AMD), proliferative diabetic retinopathy (PDR), and retinopathy of prematurity (ROP). The mechanisms underlying PA is complex and incompletely understood. In this study, we investigated the role of extracellular matrix (ECM) protein biglycan (BGN) in PA using an oxygen-induced retinopathy (OIR) mouse model, along with hypoxia (1% O2) conditions for incubating pericytes and endothelial cells in vitro. We found a significant upregulation of Bgn in the retinas of OIR mice. Intravitreal injection of Bgn-specific small interfering RNA (siRNA) in OIR mice at postnatal day 12 (P12) effectively curbed retinal PA at P17. Using cultured cells, we found that BGN expression in pericytes was highly sensitive to hypoxic stimulation compared to endothelial cells. We further showed that BGN stimulated retinal PA via the upregulation of C-X-C motif chemokine ligand 12 (CXCL12). Inhibition of the CXCL12-CXCR4 axis effectively diminished PA in OIR mouse. In conclusion, our study demonstrated the stimulatory role of BGN in retinal PA, identified the link between BGN and CXCL12 expression, and further highlighted the role of pericytes in retinal PA.

Tracking astrocyte polarization in the retina in retinopathy of prematurity

Astrocyte patterns affect the normal development of the retinal vascular network in retinopathy of prematurity (ROP), which is associated with VEGF secretion. However, the role of the astrocyte polarization in this process remains unknown. Therefore, this study aimed to track the status of A1/A2 reactive astrocytes in the retinas of the oxygen-induced retinopathy (OIR) model and their association with VEGF expression. The C57BL/6 mouse OIR model was constructed to characterize the pathological changes in ROP. Immunofluorescence of iB4 and GFAP staining was performed to observe changes in the vascular network and astrocyte pattern at different time points (P0, P7, P12, P17, and P21). C3-labeled A1 reactive and S100A10-labeled A2 reactive astrocytes and VEGF were also observed. The pattern of GFAP-labeled astrocyte was altered concurrently with the iB4-positive vascular network during OIR. Astrocyte activity was significantly weakened at P12 and significantly enhanced at P17. Notably, the number of C3-labeled A1 reactive astrocytes was significantly increased at P12, decreased at P17, and normalized at P21 in OIR models. S100A10-labeled A2 reactive astrocytes were significantly increased at P17 but did not change significantly at P12 or P17. VEGF levels were decreased at P7-P12 and increased at P12-P17. The expression pattern of VEGF was opposite to that of C3-labeled A1 reactive astrocytes and identical to that of S100A10-labeled A2 reactive astrocytes. In conclusion, the astrocyte pattern and vascular network exhibited similar changes during the OIR process, and the periods of vaso-obliteration and neo-vascularization display an abnormal activation in A1-and A2-reactive astrocytes.

m6A-methylase METTL3 promotes retinal angiogenesis through modulation of metabolic reprogramming in RPE cells

Retinal neovascularization (RNV) disease is one of the leading causes of blindness, yet the molecular underpinnings of this condition are not well understood. To delve into the critical aspects of cell-mediated angiogenesis, we analyzed our previously published single-cell data. Our analysis revealed that retinal pigment epithelium (RPE) cells serve a crucial promotional function in angiogenesis. RPE cells were regulated by N6-methyladenosine (m6A). Next, we detected several critical m6A methylase in hypoxic ARPE-19 cells and in oxygen-induced retinopathy (OIR) mice, our results revealed a significant decrease in the level of methyltransferase like 3 (METTL3). METTL3 specific inhibitor STM2457 intravitreal injection or METTL3 conditional knockout mice both showed a significantly reduced neovascularization area of retina. Additionally, the angiogenesis-related abilities of human retinal endothelial cells (HRECs) were diminished after co-cultured with ARPE-19 treated with STM2457 or sh-METTL3 in vitro. Furthermore, through the integration of Methylated RNA immunoprecipitation (MeRIP) sequencing and RNA sequencing, we discovered that the metabolic enzyme quinolinate phosphoribosyltransferase (QPRT) was directly modified by METTL3 and recognized by the YTH N6-methyladenosine RNA binding protein C1 (YTHDC1). Moreover, after over-expressing QPRT, the angiogenic abilities of HRECs were improved through the phosphorylated phosphatidylinositol-3-kinase (p-PI3K)/ phosphorylated threonine kinase (p-AKT) pathway. Collectively, our study provided a novel therapeutic target for retinal angiogenesis.

Implementation of Artificial Intelligence in Retinopathy of Prematurity Care: Challenges and Opportunities

The diagnosis of retinopathy of prematurity (ROP) is primarily image-based and suitable for implementation of artificial intelligence (AI) systems. Increasing incidence of ROP, especially in low and middle-income countries, has also put tremendous stress on health care systems. Barriers to the implementation of AI include infrastructure, regulatory, legal, cost, sustainability, and scalability. This review describes currently available AI and imaging systems, how a stable telemedicine infrastructure is crucial to AI implementation, and how successful ROP programs have been run in both low and middle-income countries and high-income countries. More work is needed in terms of validating AI systems with different populations with various low-cost imaging devices that have recently been developed. A sustainable and cost-effective ROP screening program is crucial in the prevention of childhood blindness.

Safety and efficacy of ripasudil eye drops in preterm infants with retinopathy of prematurity: phase 1/2, open label, single-arm trial

PURPOSE

To assess the safety and efficacy of ripasudil for retinopathy of prematurity (ROP).

STUDY DESIGN

Phase 1/2, multicenter, open-label, single-arm, 12-week clinical trial.

METHODS

Infants born with gestational age (GA) of ≤ 32 weeks or weight of ≤ 1500 g with zone I or II, ≥ stage 1, ROP in both eyes were enrolled. Ripasudil eye drops were administered to patients in both eyes. Phase 1 was a dose-escalation study (once daily for 1 week, then twice daily for 2 weeks); an additional dosing up to 9 weeks was allowed if no safety issues occurred. In phase 2, ripasudil was administered twice daily for up to 12 weeks. Adverse events were assessed. The proportion of patients with type 1 ROP progression, number of days for type 1 ROP progression, and progression to the most advanced ROP stage were estimated.

RESULTS

Twenty-four infants were enrolled (phase 1, n = 3; phase 2, n = 21). Nineteen and four patients experienced systemic and ocular adverse events, respectively. Efficacy endpoints were not different between the ripasudil and historical control groups. However, in the GA ≤ 27 weeks subgroup, fewer patients progressed to type 1 ROP in the ripasudil than in the historical control group (P = 0.09). In the GA ≤ 27 weeks subgroups, the 25th percentile for the number of days for type 1 ROP progression was 22 days in the historical control group and 44 days in the ripasudil group.

CONCLUSION

Ripasudil was safe and inhibited/delayed type 1 ROP progression, especially in infants with short GA.

MDSCs promote pathological angiogenesis in ocular neovascular disease

BACKGROUND

Ocular neovascular diseases, which contribute significantly to vision loss, lack effective preventive treatments. Recent studies have highlighted the significant involvement of immune cells in neovascular retinopathy. Myeloid-derived suppressor cells (MDSCs) promote the development of neovascularization, but it is unknown whether they participate in pathological neovascularization and whether they are expected to be a therapeutic target.

METHOD

We investigated the role of MDSCs in promoting pathological angiogenesis using an oxygen-induced retinopathy (OIR) model, employing flow cytometry, immunofluorescence, and smart-seq analysis. Then, we evaluated the proportion of MDSCs in patient blood samples using flow cytometry. Additionally, we assessed the effect of MDSC depletion using an anti-Gr-1 monoclonal antibody on retinal vasculopathy and alterations in retinal microglia.

RESULTS

In the OIR model, an elevated ratio of MDSCs was observed in both blood and retinal tissue during phase II (Neovascularization). The depletion of MDSCs resulted in reduced retinal neovascularization and vaso-obliteration, along with a decrease in microglia within the neovascularization area. Furthermore, analysis of gene transcripts associated with MDSCs indicated activation of vascular endothelial growth factor (VEGF) regulation and inflammation. Importantly, infants with ROP exhibited a higher proportion of MDSCs in their blood samples.

CONCLUSION

Our results suggested that excessive MDSCs represent an unrecognized feature of ocular neovascular diseases and be responsible for the retinal vascular inflammation and angiogenesis, providing opportunities for new therapeutic approaches to ocular neovascular disease.

C176-loaded and phosphatidylserine-modified nanoparticles treat retinal neovascularization by promoting M2 macrophage polarization

Retinal neovascularization (RNV), a typical pathological manifestation involved in most neovascular diseases, causes retinal detachment, vision loss, and ultimately irreversible blindness. Repeated intravitreal injections of anti-VEGF drugs were developed against RNV, with limitations of incomplete responses and adverse effects. Therefore, a new treatment with a better curative effect and more prolonged dosage is demanding. Here, we induced macrophage polarization to anti-inflammatory M2 phenotype by inhibiting cGAS-STING signaling with an antagonist C176, appreciating the role of cGAS-STING signaling in the retina in pro-inflammatory M1 polarization. C176-loaded and phosphatidylserine-modified dendritic mesoporous silica nanoparticles were constructed and examined by a single intravitreal injection. The biosafe nanoparticles were phagocytosed by retinal macrophages through a phosphatidylserine-mediated "eat me" signal, which persistently release C176 to suppress STING signaling and thereby promote macrophage M2 polarization specifically. A single dosage can effectively alleviate pathological angiogenesis phenotypes in murine oxygen-induced retinopathy models. In conclusion, these C176-loaded nanoparticles with enhanced cell uptake and long-lasting STING inhibition effects might serve as a promising way for treating RNV.

Reduction of pathological retinal neovascularization, vessel obliteration, and artery tortuosity by PEDF protein in an oxygen-induced ischemic retinopathy rat model

Retinopathy of prematurity (ROP) is a severe retinal disease in premature infants characterized by pathological neovascularization, obliteration of retinal vessels and increased vessel tortuosity. Currently, there are no completely satisfactory treatments for ROP. Pigment epithelium-derived factor (PEDF), a potent inhibitor of angiogenesis, appears late in gestation and its deficiency may be linked to development of ROP. This study investigates the preclinical efficacy of PEDF protein alone or in combination with VEGF antagonists for treating ROP. The safety of PEDF protein in the rat eye was assessed using functional in vivo measurements and histology. The efficacy of intravitreal injections (IVI) of various treatments was evaluated in a rat oxygen-induced retinopathy (OIR) model using in vivo imaging and flatmount analyses. No functional or histological side-effects were found in rat eyes after intravitreal PEDF protein injection. PEDF protein alone or combined with anti-VEGF drugs significantly reduced pathological neovascularization and vessel obliteration, comparable to the effects of anti-VEGF drugs alone. Regarding arterial tortuosity, treatment with a combination of PEDF, and VEGF antagonist was more effective than treatment with anti-VEGF alone. IVI of PEDF protein is safe. PEDF protein alone or combined with VEGF antagonists shows similar efficacy in reducing pathological neovascularization and vessel obliteration as anti-VEGF agents. Furthermore, only treatments involving PEDF protein, alone or with VEGF antagonists, significantly improved the quality of retinal vasculature. Thus, PEDF protein alone or combined with anti-VEGF agents presents a promising alternative to current anti-VEGF treatments for ROP.

The impact of gut microbiota on morbidities in preterm infants

The gut microbiota undergoes substantial development from birth, and its development in the initial years of life has a potentially lifelong effect on the health of the individual. However, various factors can disrupt the development of the gut microbiota, leading to a condition known as dysbiosis, particularly in preterm infants. Current studies involving adults have suggested that the gut microbiota not only influences the gut but also has multidimensional effects on remote organs; these pathways are often referred to as the gut-organ axis. Imbalance of the gut microbiota may lead to the development of multiple diseases. Recent studies have revealed that gut dysbiosis in preterm infants may cause several acute morbidities-such as necrotizing enterocolitis, late-onset sepsis, bronchopulmonary dysplasia, and retinopathy of prematurity-and it may also influence long-term outcomes including neurodevelopment and somatic growth. This review mainly presents the existing evidence regarding the relationships between the gut microbiota and these morbidities in preterm infants and explores the role of the gut-organ axis in these morbidities. This paper thus offers insights into the future perspectives on microbiota interventions for promoting the health of preterm infants.

Comparison of Different Doses of Oral and Ocular Propranolol for Retinopathy of Prematurity: A Network Meta-Analysis

OBJECTIVE

The efficacy and safety of propranolol for retinopathy of prematurity (ROP) remain under debate. This network meta-analysis (NMA) focuses on whether a ranking may be established for different dose levels of propranolol as treatment of ROP in terms of stage progression as the primary outcome, with appearance of plus disease and need for anti-vascular endothelial growth factors (anti-VEGFs) or laser therapy as secondary endpoints.

METHODS

Fourteen studies (10 randomised controlled trials, three single-arm trials and one retrospective observational study) of 474 patients treated with oral or ocular propranolol were retrieved from databases up to April 2024. Meta-insight and model-based NMA were undertaken to evaluate the propranolol dose-response relationship. Studies were evaluated for model fit, risk of bias and Confidence of evidence In Network Meta-Analysis (CINeMA). Effect sizes were determined as odds ratio (OR) with 95% credible interval (CrI).

RESULTS

Bayesian analysis showed a trend towards improved effects for propranolol given at late stages (stages 2-3; S23) of ROP progression compared with its administration at earlier stages (stages 0-1; S01). OR values for oral propranolol 1.5 and 2 mg/kg/day given at S23 were 0.13 (95% CrI 0.04-0.37) and 0.16 (95% CrI 0.04-0.61), respectively, while given at S01 were 0.28 (95% CrI 0.02-2.96) and 0.78 (95% CrI 0.14-4.43), respectively. Similarly, OR of eye propranolol 0.2% at S23 was 0.37 (95% CrI 0.09-1.00) versus an S01 OR of 0.64 (95% CrI 0.21-2.04). Surface under the cumulative ranking curve (SUCRA) analyses confirmed best probability values for oral propranolol 1.5-2 mg/kg followed by eye propranolol 0.2%, all at S23. Model-based NMA showed nonlinearity in the dose-response for oral propranolol with a trend to greater maximal effect for its administration at late versus early stages. For secondary endpoints, lower risk values were found with oral propranolol 1.5 mg/kg/day at S23 for progression to plus disease (OR 0.14; 95% CrI 0.02-0.84) and need for anti-VEGFs (OR 0.23; 95% CrI 0.05-0.93) and laser (OR 0.16; 95% CrI 0.02-1.10) therapies also followed by eye propranolol 0.2%, and a similar profile was obtained with SUCRA analysis. Lower doses (0.5-1.0 mg/kg/day) of oral propranolol retained efficacy. Threat of adverse events was estimated as risk difference versus control with no difference for eye propranolol 0.2% and oral propranolol 0.5 mg/kg/day, modest increases of risk for oral propranolol 1.0 and 1.5 mg/kg/day and the highest risk difference for oral propranolol 2.0 mg/kg/day (0.06; 95% CI -0.01 to 0.13).

CONCLUSION

A diminished risk of disease progression and need for additional treatment was obtained with propranolol in ROP, but safety is a potential concern. Propranolol eye micro-drops (0.2%) can be as efficacious as oral propranolol. Nonetheless, the evidence is limited due to the paucity and quality of the available studies.

Icariin alleviates oxygen-induced retinopathy by targeting microglia hexokinase 2

Retinopathy of prematurity (ROP) is a retinal disease-causing retinal neovascularization that can lead to blindness. Oxygen-induced retinopathy (OIR) is a widely used ROP animal model. Icariin (ICA) has anti-oxidative and anti-inflammation properties; however, whether ICA has a regulatory effect on OIR remains unclear. In this study, ICA alleviated pathological neovascularization, microglial activation and blood-retina barrier (BRB) damage in vivo. Further results indicated that endothelial cell tube formation, migration and proliferation were restored by ICA treatment in vitro. Proteomic microarrays and molecular mimicry revealed that ICA can directly bind to hexokinase 2 (HK2) and decrease HK2 protein expression in vivo and in vitro. In addition, ICA inhibited the AKT/mTOR/HIF1α pathway activation. The effects of ICA on pathological neovascularization, microglial activation and BRB damage disappeared after HK2 overexpression in vivo. Similarly, the endothelial cell function was revised after HK2 overexpression. HK2 overexpression reversed ICA-induced AKT/mTOR/HIF1α pathway inhibition in vivo and in vitro. Therefore, ICA prevented pathological angiogenesis in OIR in an HK2-dependent manner, implicating ICA as a potential therapeutic agent for ROP.

Continuous oxygen saturation and risk of retinopathy of prematurity in a Japanese cohort

BACKGROUND/AIMS

We assessed the associations between retinopathy of prematurity (ROP) and continuous measurements of oxygen saturation (SpO2), and developed a risk prediction model for severe ROP using birth data and SpO2 data.

METHODS

This retrospective study included infants who were born before 30 weeks of gestation between August 2009 and January 2019 and who were screened for ROP at a single hospital in Japan. We extracted data on birth weight (BW), birth length, gestational age (GA) and minute-by-minute SpO2 during the first 20 days from the medical records. We defined four SpO2 variables using sequential measurements. Multivariate logistic regression was used to develop a model that combined birth data and SpO2 data to predict treatment-requiring ROP (TR-ROP). The model's performance was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

Among 350 infants, 83 (23.7%) required ROP treatment. The SpO2 variables in infants with TR-ROP differed significantly from those with non-TR-ROP. The average SpO2 and high SpO2 showed strong associations with GA (r=0.73 and r=0.70, respectively). The model incorporating birth data and the four SpO2 variables demonstrated good discriminative ability (AUC=0.83), but it did not outperform the model incorporating BW and GA (AUC=0.82).

CONCLUSION

Data obtained by continuous SpO2 monitoring demonstrated valuable associations with severe ROP, as well as with GA. Differences in the distribution of average SpO2 and high SpO2 between infants with TR-ROP and non-TR-ROP could be used to establish efficient cut-off values for risk determination.

A comparative study of stereopsis in term and preterm children with and without retinopathy of prematurity

PURPOSE

To evaluate stereopsis in term-born, preterm, and preterm children with and without retinopathy of prematurity (ROP) and its treatment.

METHODS

The cross-sectional study included 322 children between 3 and 11 years of age born term or preterm, with or without ROP, and with or without treatment for ROP. The ROP treatments were laser therapy, intravitreal injection (IVI) of anti-vascular endothelial growth factor, or their combination. Stereoacuity was measured using the Titmus Stereo Test, and the results among various age groups were analyzed.

RESULTS

Stereopsis was found to improve with increasing age at testing (P < 0.001) across the entire study population. The term group exhibited significantly better stereoacuity than the preterm group (P < 0.001). At 3-5 years and 6-8 years, the preterm children without ROP exhibited significantly better stereoacuity than did those with ROP (P < 0.001 and P = 0.02, respectively); however, at 9-11 years, both groups exhibited similar stereoacuity (P = 0.34). The stereoacuity in the children with untreated ROP was similar to that of the children with treated ROP in all age groups (P > 0.05). No significant differences in stereopsis were identified between children with ROP treated with laser versus with IVI (P > 0.05). From multivariate analysis, younger age at testing (P = 0.001) and younger gestational age (P < 0.001) were associated with poorer stereopsis.

CONCLUSIONS

Stereopsis development gradually improved with age in all groups. The children born preterm exhibited poorer stereoacuity than those born term. Children with ROP treated with laser photocoagulation versus IVI may exhibit similar levels of stereoacuity. Younger age at testing and gestational age were independent risk factors for poorer stereoacuity.

Vascular development analysis: a study for tertiary anti-vascular endothelial growth factor therapy after second reactivation of retinopathy of prematurity

Purpose

To observe the vascular development results of tertiary anti-vascular endothelial growth factor (anti-VEGF) therapy following spontaneous second reactivation of retinopathy of prematurity (ROP).

Methods

This retrospective study included 22 infants (42 eyes) with Type 1 or aggressive ROP (A-ROP) who received three anti-VEGF drug treatments for ROP from January 2018 to December 2022. The vascular growth, possible associated risk factors, and the retinal vascularization (DB/DF ratio) were assessed.

Results

The mean follow-up was 17.6 months. After the 3rd intravitreal injection, seven eyes showed complete vascularization (Group 1), while the remaining 35 eyes demonstrated persistent avascular retina (PAR) (Group 2). In Group 2, 17 eyes maintained a stable state and were classified in the regression subgroup. The other 18 eyes developed a 3rd reactivation (reactivation subgroup) and were treated with laser photocoagulation (LPC).Birth weight (BW) was significantly lower in Group 2 than in Group 1 (p < 0.001). The decision tree analysis shows that only infants weighing more than 1,250 g (17.50%) had a chance to achieve complete retinal vascularization. The possibility of PAR was higher in patients with BW <1,250 g than ≥1,250 g (70.00% vs. 12.50%). In addition, most infants with BW ≥ 1,290 g and initial ROP disease in Zone I or posterior Zone II developed PAR.

Conclusion

Tertiary IVR can successfully treat a second ROP reactivation and improve peripheral retinal vascularization. BW is the most significant factor related to complete retinal vascularization. Our decision tree model may be helpful in predicting the prognosis of anti-VEGF drugs in the event of a second ROP reactivation.

Characteristics of retinal vascularization in reactivated retinopathy of prematurity requiring treatment and clinical outcome after reinjection of ranibizumab

This study aimed to determine whether the state of retinal vascularization after anti-vascular endothelial growth factor (anti-VEGF) injection can help predict the risk of reactivated retinopathy of prematurity (ROP) requiring treatment and whether repeated ranibizumab injection will be effective in such cases. We retrospectively reviewed 24 infants (43 eyes) who received ranibizumab monotherapy between January 2021 and December 2022. All eyes were classified as having non-retreated ROP or retreated ROP. The state of ROP at the time of treatment, the time required for resolution of plus disease, and the extent of vascularization at 4 and 8 weeks after treatment were analyzed. Extent of temporal retinal vascularization was measured with serial fundus images using disc-fovea distance (DF) unit and disc diameter (DD). Reactivated ROP requiring treatment occurred in six infants (25.0%) and ten eyes (23.3%) after ranibizumab treatment. The mean retreatment interval was 9.0 ± 3.3 weeks (range 4-16). In the retreated ROP group, the time required for the resolution of plus disease after primary injection was longer compared to the control group (13.3 days vs 5.2 days), with a mean ROP regression time of 3.4 weeks. All eyes in the retreated ROP showed retinal vascularization < 0.5 DF from the original site at 4 weeks after injection. In 90% of cases with retreated ROP, the extent of vascularization at 8 weeks after injection was within 1 DF from the original ROP site, and all cases showed reactivation in the posterior Zone II area. The extent of retinal neovascularization in the retreated group was an average of 0.7 DD (vs 1.7 DD) and 1.3 DD (vs 3.3 DD) at 4 and 8 weeks after injection, respectively. After ranibizumab retreatment, only one reactivated case with vitreous traction progressed to focal retinal detachment, while all other cases regressed with peripheral vascular development. The continuation of delayed retinal blood vessel development after ≥ 8 weeks may indicate a high likelihood of reactivated ROP requiring treatment. In the absence of vitreous traction, ranibizumab reinjection is likely to be effective in treating reactivated ROP requiring treatment.

Recent Advances in Nanomedicine for Ocular Fundus Neovascularization Disease Management

As an indispensable part of the human sensory system, visual acuity may be impaired and even develop into irreversible blindness due to various ocular pathologies. Among ocular diseases, fundus neovascularization diseases (FNDs) are prominent etiologies of visual impairment worldwide. Intravitreal injection of anti-vascular endothelial growth factor drugs remains the primary therapy but is hurdled by common complications and incomplete potency. To renovate the current therapeutic modalities, nanomedicine emerged as the times required, which is endowed with advanced capabilities, able to fulfill the effective ocular fundus drug delivery and achieve precise drug release control, thus further improving the therapeutic effect. This review provides a comprehensive summary of advances in nanomedicine for FND management from state-of-the-art studies. First, the current therapeutic modalities for FNDs are thoroughly introduced, focusing on the key challenges of ocular fundus drug delivery. Second, nanocarriers are comprehensively reviewed for ocular posterior drug delivery based on the nanostructures: polymer-based nanocarriers, lipid-based nanocarriers, and inorganic nanoparticles. Thirdly, the characteristics of the fundus microenvironment, their pathological changes during FNDs, and corresponding strategies for constructing smart nanocarriers are elaborated. Furthermore, the challenges and prospects of nanomedicine for FND management are thoroughly discussed.

Comparison of different agents and doses of anti-vascular endothelial growth factors (aflibercept, bevacizumab, conbercept, ranibizumab) versus laser for retinopathy of prematurity: A network meta-analysis

Laser photocoagulation (LPC) and/or intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections constitute the current standard treatment for retinopathy of prematurity (ROP). This network meta-analysis focus on whether a ranking of interventions may be established for different dose levels of intravitreal injection of anti-VEGF agents (aflibercept, bevacizumab, conbercept, ranibizumab) as primary treatments for ROP versus laser in terms of retreatment rate as primary outcome, and time to retreatment and refractive error as secondary endpoints, since best anti-VEGF dosage remains under debate. Sixty-eight studies (15 randomized control trials and 53 nonrandomized studies) of 12,356 eyes of 6445 infants were retrieved from databases (2005 Jan. - 2023 June). Studies were evaluated for model fit, risk of bias and confidence of evidence in Network Meta-Analysis (CINeMA). Bayesian NMA showed that anti-VEGF drugs were not inferior to laser in terms of retreatment rate. For intravitreal bevacizumab (IVB), doses half of the conventional infant dose showed a low risk of retreatment rate (risk ratio (RR) of 1.43; 95% credible interval (CrI): 0.508, 4.03). On probability ranking as surface under the cumulative ranking curve (SUCRA) plot, half dose of bevacizumab had a better position than conventional and augmented (1.2-2 times the regular dose) doses. A similar probability trend was observed for half vs. conventional doses of aflibercept and ranibizumab. Conventional infant dose of conbercept showed the lowest risk for retreatment (RR 0.846; 95% CrI: 0.245, 2.91). For secondary endpoints, lower doses of anti-VEGF agents were associated with shorter times to retreatment. The largest changes were noted for the augmented doses of bevacizumab and ranibizumab (0.3 mg) with means of 14.1 weeks (95% CrI: 6.65, 21.6) and 12.8 weeks (95% CrI: 3.19, 20.9), respectively. Finally, NMA demonstrated better refractive profile for anti-VEGF than laser therapy, especially for the conventional infant doses of bevacizumab and ranibizumab which exhibited a significantly better refractive profile than LPC, with mean differences of 1.67 (spherical equivalent - diopters) (95% CrI: 0.705, 2.67) and 2.19 (95% CrI: 0.782, 3.59), respectively. In the SUCRA plots, LPC had a markedly different position with a higher probability for myopia. Further clinical trials comparing different intravitreal doses of anti-VEGF agents are needed, but our findings suggest that low doses of these drugs retain efficacy and may reduce ocular and systemic undesired events.

Multifunctional nano-in-micro delivery systems for targeted therapy in fundus neovascularization diseases

Fundus neovascularization diseases are a series of blinding eye diseases that seriously impair vision worldwide. Currently, the means of treating these diseases in clinical practice are continuously evolving and have rapidly revolutionized treatment opinions. However, key issues such as inadequate treatment effectiveness, high rates of recurrence, and poor patient compliance still need to be urgently addressed. Multifunctional nanomedicine can specifically respond to both endogenous and exogenous microenvironments, effectively deliver drugs to specific targets and participate in activities such as biological imaging and the detection of small molecules. Nano-in-micro (NIM) delivery systems such as metal, metal oxide and up-conversion nanoparticles (NPs), quantum dots, and carbon materials, have shown certain advantages in overcoming the presence of physiological barriers within the eyeball and are widely used in the treatment of ophthalmic diseases. Few studies, however, have evaluated the efficacy of NIM delivery systems in treating fundus neovascular diseases (FNDs). The present study describes the main clinical treatment strategies and the adverse events associated with the treatment of FNDs with NIM delivery systems and summarizes the anatomical obstacles that must be overcome. In this review, we wish to highlight the principle of intraocular microenvironment normalization, aiming to provide a more rational approach for designing new NIM delivery systems to treat specific FNDs.

Contemporary Patterns and Underlying Causes of Vitrectomy in Pediatric and Adolescent Patients: A Nationwide, Population-Based Analysis

PURPOSE

We determined the incidence, etiology, and longitudinal trends of vitreoretinal diseases necessitating pars plana vitrectomy (PPV) in the pediatric and adolescent population.

DESIGN

Nationwide, population-based cohort study.

METHODS

This study utilized data extracted from the Korean National Health Claims database spanning from 2009 to 2020. All pediatric and adolescent patients (under 20 years of age) who underwent PPV across the Korean population were included. The cumulative incidence of PPV was estimated from 2009 to 2020, with 2009 to 2011 as the washout period. The annual trends of PPV incidence, the proportion of each etiology, and comorbidity were estimated based on sex and specific age groups.

RESULTS

In total, 1913 patients, including 83 infants, 746 pediatric patients, and 1084 adolescents, were newly identified as having undergone PPV surgery. The cumulative incidence of PPV surgery per 100,000 individuals was 21.42 (95% CI, 21.41-21.43). The rate of PPV was 2.4 times higher for males than females, and the rate of trauma as a comorbidity was also higher for males than females (13.1% vs 4.8%). Among males aged 5 years and older, the incidence of PPV nearly halved from 2011 to 2020. Among the primary etiologies, ROP had the highest rate (72%) in infants (under 1 year), while RD was most common (63%) in individuals aged 5 to 19 years. Myopia was present in 30.3% of patients, and atopic dermatitis was present in 31.8% of all patients.

CONCLUSION

The primary etiologies underlying the need for PPV in the pediatric and adolescent populations vary by sex and age group. The incidence of PPV continues to decline in the adolescent population. Therefore, tailored patient education and age-specific etiological examination are recommended.

Corneal Endothelial Morphology and Ocular Biometric Indexes in Premature Children With and Without Retinopathy of Prematurity

Purpose

The purpose of this study was to analyze human corneal endothelial cells (HCECs) morphology and ocular biometrics in premature (PM) children with or without retinopathy of prematurity (ROP).

Methods

Retrospective data on patient demographics, HCECs status, and ocular biometrics with at least 2 visits between 2016 and 2021 were reviewed. The main outcomes were endothelial cell density (ECD), coefficient of variation (CV), hexagonal cell ratio (HEX), central corneal thickness (CCT), axial length, anterior chamber depth, keratometry, corneal diameter, pupil diameter, and refraction status. Generalized estimating equation was used to evaluate the differences between PM no-ROP and ROP groups. We also analyzed the trend of ECD, CV, HEX, and CCT change with age between groups.

Results

The study included 173 PM patients without ROP and 139 patients with ROP. A total of 666 and 544 measurements were recorded in the PM no-ROP and ROP groups, respectively. The ROP group had higher spherical power, myopic spherical equivalent (SE), and steeper steep keratometry (K; P < 0.05). The ROP group had higher CV (P = 0.0144), lower HEX (P = 0.0012) and thicker CCT (P = 0.0035). In the HCECs parameters, the ROP group had slower ECD decrement (P < 0.0001), faster CV decrement (P = 0.0060), and faster HEX increment (P = 0.0001). A difference in corneal morphology changes between the ROP and PM no-ROP groups were prominent in patients with lower gestational age (GA) in the subgroup analysis.

Conclusions

Worse HCECs morphology and higher myopic status were initially observed in patients with prior ROP but not in PM patients with no-ROP. ECD and HCECs morphology improved with age, especially in patients with low GA.

The role of pericyte in ocular vascular diseases

Pericytes are located in the stromal membrane of the capillary outer wall and contain endothelial cells (ECs). They are pivotal in regulating blood flow, enhancing vascular stability, and maintaining the integrity of the blood-retina barrier (BRB)/blood-brain barrier (BBB). The pluripotency of pericytes allows them to differentiate into various cell types, highlighting their significance in vascular disease pathogenesis, as demonstrated by previous studies. This potential enables pericytes to be a potential biomarker for the diagnosis and a target for treatment of vascular disorders. The retina, an essential part of the eyeball, is an extension of cerebral tissue with a transparent refractive medium. It offers a unique window for assessing systemic microvascular lesions. Routine fundus examination is necessary for patients with diabetes and hypertension. Manifestations, such as retinal artery tortuosity, dilation, stenosis, and abnormal arteriovenous anastomosis, serve as typical hallmarks of retinal vasculopathy. Therefore, studies of ocular vascular diseases significantly facilitate the exploration of systemic vascular diseases.

Efficacy comparison of 21 interventions to prevent retinopathy of prematurity: a Bayesian network meta-analysis of randomized controlled trials

BACKGROUND

The objective of this study was to evaluate the comparative efficacy of current interventions for the prevention of retinopathy of prematurity (ROP) in premature infants.

METHODS

A network meta-analysis (NMA) was performed. We searched PubMed, Web of Science, Scopus, Embase, and the Cochrane Library for relevant studies from their inception to May 5, 2022. Publications were eligible for our study if they were randomized controlled trials (RCTs) involving preterm infants at <37 weeks of gestational age and reported the incidence of any-stage ROP treated with the interventions of interest. The overall effect was pooled using the random effects model.

RESULTS

We identified 106 RCTs (involving 23894 participants). This NMA showed that vitamin A supplementation markedly reduced the incidence of ROP, in comparison with placebo (odds ratio [OR] = 0.59, 95% credible interval [95% CrI] 0.33, 0.85), fish oil-based lipid emulsion (OR = 0.57, 95% CrI 0.24, 0.90), early erythropoietin (OR = 0.51, 95% CrI 0.34, 0.98), probiotics (OR = 0.48, 95% CrI 0.32, 0.97), and human milk (OR = 0.50, 95% CrI 0.21, 0.78). Vitamin A supplementation has the highest probability of being the best option for reducing the ROP risk compared with the other 20 interventions based on its surface under the cumulative ranking curve (SUCRA) value (SUCRA = 92.50%, 95% CrI 0.71, 1.00).

CONCLUSIONS

Our findings suggest that among 21 interventions, vitamin A supplementation might be the best method of preventing ROP. This NMA offers an important resource for further efforts to develop preventive strategies for ROP.

Ferroptosis as a potential therapeutic target for age-related macular degeneration

Cell death plays a crucial part in the process of age-related macular degeneration (AMD), but its mechanisms remain elusive. Accumulating evidence suggests that ferroptosis, a novel form of regulatory cell death characterized by iron-dependent accumulation of lipid hydroperoxides, has a crucial role in the pathogenesis of AMD. Numerous studies have suggested that ferroptosis participates in the degradation of retinal cells and accelerates the progression of AMD. Furthermore, inhibitors of ferroptosis exhibit notable protective effects in AMD, underscoring the significance of ferroptosis as a pivotal mechanism in the death of retinal cells during the process of AMD. This review aims to summarize the molecular mechanisms of ferroptosis in AMD, enumerate potential inhibitors and discuss the challenges and future opportunities associated with targeting ferroptosis as a therapeutic strategy, providing important information references and insights for the prevention and treatment of AMD.

Targeting adenosine A2A receptors for early intervention of retinopathy of prematurity

Retinopathy of prematurity (ROP) continues to pose a significant threat to the vision of numerous children worldwide, primarily owing to the increased survival rates of premature infants. The pathologies of ROP are mainly linked to impaired vascularization as a result of hyperoxia, leading to subsequent neovascularization. Existing treatments, including anti-vascular endothelial growth factor (VEGF) therapies, have thus far been limited to addressing pathological angiogenesis at advanced ROP stages, inevitably leading to adverse side effects. Intervention to promote physiological angiogenesis during the initial stages could hold the potential to prevent ROP. Adenosine A2A receptors (A2AR) have been identified in various ocular cell types, exhibiting distinct densities and functionally intricate connections with oxygen metabolism. In this review, we discuss experimental evidence that strongly underscores the pivotal role of A2AR in ROP. In particular, A2AR blockade may represent an effective treatment strategy, mitigating retinal vascular loss by reversing hyperoxia-mediated cellular proliferation inhibition and curtailing hypoxia-mediated neovascularization in oxygen-induced retinopathy (OIR). These effects stem from the interplay of endothelium, neuronal and glial cells, and novel molecular pathways (notably promoting TGF-β signaling) at the hyperoxia phase. We propose that pharmacological targeting of A2AR signaling may confer an early intervention for ROP with distinct therapeutic benefits and mechanisms than the anti-VEGF therapy.

IL1R2 promotes retinal angiogenesis to participate in retinopathy of prematurity by activating the HIF1α/PFKFB3 pathway

Retinopathy of prematurity (ROP) is the leading cause of blindness in children, but there is no safe and effective treatment available. Interleukin-1 receptor type 2 (IL1R2) acts as a decoy receptor for IL-1 may affect ROP progression. This study aimed to investigate the role of IL1R2 in ROP. A microglial cell model was established under hypoxia conditions and co-cultured with choroidal endothelial cells, while an oxygen-induced retinopathy (OIR) model was also established. Microglial activation and IL1R2 levels in retinal tissues were analyzed using immunofluorescence assay. Endothelial cell migration was evaluated by Transwell assay and scratch test, angiogenesis was assessed using ELISA and tube formation assay, and proliferation was evaluated by EdU assay. The HIF1α/PFKFB3 pathway was analyzed by western blot. We observed that IL1R2 expression was predicted to be upregulated in ROP and was increased in hypoxia-treated BV2 cells. Additionally, IL1R2 levels were upregulated in the retinal tissues of OIR mice and correlated with microglial activation. In vitro experiments, we found that hypoxia promoted endothelial cell migration, angiogenesis, proliferation, and activated the HIF1α/PFKFB3 pathway, which were rescued by IL1R2 knockdown. Moreover, NHWD-870 (a HIF1α/PFKFB3 pathway inhibitor) suppressed endothelial cell migration, angiogenesis, and proliferation induced by IL1R2 overexpression. In conclusion, IL1R2 facilitates the migration, angiogenesis, and proliferation of choroidal endothelial cells by activating the HIF1α/PFKFB3 pathway to regulate ROP progression.

Retinopathy of Prematurity-Targeting Hypoxic and Redox Signaling Pathways

Retinopathy of prematurity (ROP) is a proliferative vascular ailment affecting the retina. It is the main risk factor for visual impairment and blindness in infants and young children worldwide. If left undiagnosed and untreated, it can progress to retinal detachment and severe visual impairment. Geographical variations in ROP epidemiology have emerged over recent decades, attributable to differing levels of care provided to preterm infants across countries and regions. Our understanding of the causes of ROP, screening, diagnosis, treatment, and associated risk factors continues to advance. This review article aims to present the pathophysiological mechanisms of ROP, including its treatment. Specifically, it delves into the latest cutting-edge treatment approaches targeting hypoxia and redox signaling pathways for this condition.

Choroidal measurements in decision making for retinopathy of prematurity: a decision tree analysis

BACKGROUND

To compare the choroidal thickness and vascular profile of premature infants with ROP (retinopathy of prematurity) using a handheld SD-OCT device.

METHODS

We performed horizontal SD-OCT scans through the fovea in 115 eyes of 66 premature infants. Premature infants included 2 groups [infants with ROP requiring treatment (as treatment group) vs. infants without ROP or with ROP not- requiring treatment (as no-treatment group)] Choroidal thicknesses (CT) were measured at 5 points, including the fovea, 250 µm, and 500 µm mm nasal and temporal to the fovea. The choroidal vascularity index (CVI) and choroidal stromal index (CSI) were also calculated. The classification and regression tree (CRT) algorithm was used to predict the need for treatment based on all OCT characteristics.

RESULTS

Mean CT was higher in 500 µm nasal to the fovea compared to temporal CT (275.8 ± 64.8 and 257.1 ± 57.07, P value < 0.03). No statistically significant difference was found regarding CVI, corrected CVI, and temporal and nasal CT in the treatment group versus the no-treatment group. The foveal CT was significantly lower in ROP patients with the plus disease compared to not-plus ROP (P value = 0.03. ANOVA, Bonferroni posthoc test). CT was not significantly different between plus and pre-plus patients (P-value = 0.9, ANOVA, Bonferroni posthoc test). No significant relationship was found between the stage of ROP and choroidal thickness (P value > 0.05, GEE). The decision tree analysis showed that in infants with ROP, the most important predictor for the need for treatment is CSI.

CONCLUSION

This study delineated the possible effectiveness of choroidal measurements as an additive to decision-making for ROP. We also demonstrated that choroidal involution is associated with the presence of plus disease, not with the stage of ROP. We demonstrated that choroidal measurements are very sensitive but not specific tools for assessing the need for treatment in ROP patients.

Advances in human reproductive biomarkers

Reproductive biomarkers are important regulators in women, especially during pregnancy and childbirth. Because of their essential role in women's health, the discovery and quantification of reproductive biomarkers is of great clinical importance. Nowadays, there are many detection strategies to detect these biomarkers, including VEGF, human chorionic gonadotropin (hCG), etc. Consider the limitations and problems of conventional diagnostic methods, new methods are being developed, one of the most important being methods based on nanotechnology. This review includes a review of methods for diagnosing reproductive biomarkers, ranging from mainstream to nanotechnology-based methods. The bulk of this article is an in-depth introduction to the latest advances in biosensor and nanosensor research for the detection and quantitative identification of reproductive biomarkers.

Neonatal sepsis as a cause of retinopathy of prematurity: An etiological explanation

Retinopathy of prematurity (ROP) is a complex neonatal disorder with multiple contributing factors. In this paper we have mounted the evidence in support of the proposal that neonatal sepsis meets all requirements for being a cause of ROP (not a condition, mechanism, or even innocent bystander) by means of initiating the early stages of the pathomechanism of ROP occurrence, systemic inflammation. We use the model of etiological explanation, which distinguishes between two overlapping processes in ROP causation. It can be shown that sepsis can initiate the early stages of the pathomechanism via systemic inflammation (causation process) and that systemic inflammation can contribute to growth factor aberrations and the retinal characteristics of ROP (disease process). The combined contribution of these factors with immaturity at birth (as intrinsic risk modifier) and prenatal inflammation (as extrinsic facilitator) seems to provide a cogent functional framework of ROP occurrence. Finally, we apply the Bradford Hill heuristics to the available evidence. Taken together, the above suggests that neonatal sepsis is a causal inducer of ROP.

Discussing pathologic mechanisms of Diabetic retinopathy & therapeutic potentials of curcumin and β-glucogallin in the management of Diabetic retinopathy

Diabetic retinopathy (DR) is a form of retinal microangiopathy that occurs as a result of long-term Diabetes mellitus (DM). Patients with Diabetes mellitus typically suffer from DR as a progression of the disease that may be due to initiation and dysregulation of pathways like the polyol, hexosamine, the AGE/RAGE, and the PKC pathway, which all have negative impacts on eye health and vision. In this review, various databases, including PubMed, Google Scholar, Web of Science, and Science Direct, were scoured for data relevant to the aforementioned title. The three most common therapies for DR today are retinal photocoagulation, anti-vascular endothelial growth factor (VEGF) therapy, and vitrectomy, however, there are a number of drawbacks and limits to these methods. So, it is of critical importance and profound interest to discover treatments that may successfully address the pathogenesis of DR. Curcumin and β-glucogallin are the two potent compounds of natural origin that are already being used in various nutraceutical formulations for several ailments. They have been shown potent antiapoptotic, anti-inflammatory, antioxidant, anticancer, and pro-vascular function benefits in animal experiments. Their parent plant species have been used for generations by practitioners of traditional herbal medicine for the treatment and prevention of various eye ailments. In this review, we will discuss about pathophysiology of Diabetic retinopathy and the therapeutic potentials of curcumin and β-glucogallin one of the principal compounds from Curcuma longa and Emblica officinalis in Diabetic retinopathy.

Fundus fluorescein angiography imaging of retinopathy of prematurity in infants: A review

Fluorescein angiography in retinopathy of prematurity is increasingly utilized over the past decade. The development of ultra-wide-field imaging combined with fluorescein angiography has allowed improved visualization of the peripheral retinal vasculature. Patient cooperation in the pediatric population is particularly challenging, but hand-held digital retinal photography has shown promise and can visualize the infant retina without the need for anesthesia and intravenous access. Many features of retinopathy of prematurity and its response to laser and anti-VEGF treatment can be either exclusively or better visualized on fluorescein angiography compared to indirect ophthalmoscopy or color fundus photography. Disease treatment is gradually shifting from laser photocoagulation to intravitreal anti-VEGF agents, the latter being associated with late-onset vision-threatening sequelae. The role of fluorescein angiography in retinopathy of prematurity monitoring will continue to increase with the longer follow-up required and different clinical behavior seen with anti-VEGF treatment. We highlight the utility, safety, and importance of fluorescein angiography in the diagnosis, treatment, and follow-up of retinopathy of prematurity.

SYVN1 Promotes STAT3 Protein Ubiquitination and Exerts Antiangiogenesis Effects in Retinopathy of Prematurity Development

PURPOSE

SYVN1, a gene involved in endoplasmic reticulum-associated degradation, has been found to exert a protective effect by inhibiting inflammation in retinopathy. This study aimed to clarify whether SYVN1 is involved in the pathogenesis of retinopathy of prematurity (ROP) and its potential as a candidate for target therapy.

METHODS

Human retinal microvascular endothelial cells (hRMECs) and a mouse model of oxygen-induced retinopathy (OIR) were used to reveal the retinopathy development-associated protein expression and molecular mechanism. An adenovirus overexpressing SYVN1 or vehicle control was injected intravitreally at postnatal day 12 (P12), and the neovascular lesions were evaluated in retinal flatmounts with immunofluorescence staining, and hematoxylin and eosin staining at P17. Visual function was assessed by using electroretinogram (ERG).

RESULTS

Endogenous SYVN1 expression dramatically decreased in hRMECs under hypoxia and in ROP mouse retinas. SYVN1 regulated the signal transducer and activator of transcription 3 (STAT3)/vascular endothelial growth factor (VEGF) axis. SYVN1 overexpression promoted ubiquitination and degradation of STAT3, decreased the levels of phospho-STAT3, secretion of VEGF, and formation of neovascularization in hRMECs, which could be rescued by STAT3 activator treatment. In addition, SYVN1 overexpression prevented neovascularization and extended physiologic retinal vascular development in the retinal tissues of OIR mice without affecting retinal function.

CONCLUSIONS

SYVN1 has a protective effect against OIR, and the molecular mechanisms are partly through SYVN1-mediated ubiquitination of STAT3 and the subsequent downregulation of VEGF. These findings strongly support our assumption that SYVN1 confers ROP resistance and may be a potentially novel pharmaceutical target against proliferative retinopathy.

MicroRNA-124-3p Attenuated Retinal Neovascularization in Oxygen-Induced Retinopathy Mice by Inhibiting the Dysfunction of Retinal Neuroglial Cells through STAT3 Pathway

MicroRNA (miRNA) is a non-coding RNA that can regulate the expression of many target genes, and it is widely involved in various important physiological activities. MiR-124-3p was found to associate with the normal development of retinal vessels in our previous study, but the mechanism of its anti-angiogenic effect on pathological retinal neovascularization still needed to be explored. Therefore, this study aimed to investigate the effect and mechanism of miR-124-3p on retinal neovascularization in mice with oxygen-induced retinopathy (OIR). Here, we found that intravitreal injection of miR-124-3p agomir attenuated pathological retinal neovascularization in OIR mice. Moreover, miR-124-3p preserved the astrocytic template, inhibited reactive gliosis, and reduced the inflammatory response as well as necroptosis. Furthermore, miR-124-3p inhibited the signal transducer and activator of transcription 3 (STAT3) pathway and decreased the expression of hypoxia-inducible factor-1α and vascular endothelial growth factor. Taken together, our results revealed that miR-124-3p inhibited retinal neovascularization and neuroglial dysfunction by targeting STAT3 in OIR mice.

VEGF Detection via Impedance Spectroscopy on Surface Functionalized Interdigitated Biosensor

Vascular endothelial growth factor (VEGF), a clinically important biomarker, often plays a key role in angiogenesis, would healing, tumor growth, lung development, and in retinal diseases. Hence, detecting and quantifying VEGF is deemed medically important in clinical diagnosis for many diseases. In this report, a simple yet highly cost-effective platform was proposed for VEGF protein detection using commercially available interdigitated sensors that are surface modified to present DNA optimally for VEGF capture. The dielectric characteristics between the fingers of the sensor were modulated by the negatively charged aptamer-VEGF capture, and the impedance was estimated using an impedance analyzer. Impedance-spectra tests were compared among pristine unmodified surfaces, functionalized monolayer surfaces, and aptamer-grafted surfaces in order to evaluate the efficacy of VEGF detection. From our results, the sensitivity experiments as conducted showed the ability of the interdigitated sensor to detect VEGF at a low concentration of 5 pM (200 pg/mL). The specificity of the functionalized sensor in detecting VEGF was further examined by comparing the impedance to platelet-derived growth factor, and the results confirm the specificity of the sensor. Finally, the Nyquist plot of impedance spectra was also presented to help data visualization and the overall performance of the device was found to be a highly suitable template for a smart biosensor for the detection of VEGF.

Identification and clinical significance of tsRNAs and miRNAs in PBMCs of treatment-requiring retinopathy of prematurity

The aim of the study is to reveal the expression profiling and clinical significance of peripheral blood mononuclear cell (PBMC) tRNA-derived small RNAs (tsRNAs) and microRNAs (miRNAs) of premature infants with treatment-requiring retinopathy of prematurity (ROP). Significantly altered tsRNAs and miRNAs were screened using small RNA sequencing. RT-qPCR was used to verify the altered RNAs identified by small RNA transcriptomics. The target genes, their enriched functions, and possibly involved signaling pathways were identified by bioinformatics analyses. According to the small RNA sequencing, 125 tsRNAs and 205 miRNAs were significantly altered in PBMCs obtained from infants with treatment-requiring ROP compared with the premature controls without retinopathy. We preliminarily validated the significant alterations of 6 tsRNAs and 9 miRNAs. The target genes for those tsRNAs were enriched for cellular macromolecule metabolic process, intracellular anatomical structure, transcription regulatory region nucleic acid binding, and Th17 cell differentiation; those of the altered miRNAs were enriched for the developmental process, cell junction, DNA-binding transcription activator activity, and FoxO signaling pathway. By verification with the extended sample size, we identified tsRNAs and miRNAs that could be potential biomarkers with clinical values. The study recognized the alterations and clinical significance of changed tsRNA/miRNA profiles in PBMCs from premature infants with ROP. These significantly altered tsRNAs and miRNAs might be useful as potential diagnostic biomarkers and molecular targets for treatment-requiring ROP.

Retinopathy of prematurity: risk stratification by gestational age

OBJECTIVE

To identify gestational age (GA) specific risk factors for severe ROP (sROP).

STUDY DESIGN

Single-center cohort stratified by GA into <24 weeks, 24-26 weeks and ≥27 weeks.

RESULTS

132/1106 (11.9%) developed sROP. Time to full feeds was the only risk factor [HR 1.003 (1.001-1.006), p = 0.04] for infants<24 weeks GA. For infants 24-26 weeks GA, a higher GA was protective [HR 0.66 (0.51-0.85), p < 0.01], whereas steroids for bronchopulmonary dysplasia (BPD) [HR 2.21 (1.28-3.26), p < 0.01], patent ductus arteriosus (PDA) ligation [HR 1.99 (1.25-3.11), p < 0.01] and use of nitric oxide [HR 1.96 (1.11-3.30), p = 0.01] increased the hazard of sROP. Increasing birthweight was protective [HR 0.70 (0.54-0.89), p < 0.01] in infants ≥27 weeks GA. Cumulative hazard of sROP reached 1.0 by fifteen weeks for <24 weeks GA, 0.4 by twenty weeks for 24-26 weeks GA, and 0.05 by twenty weeks after birth for ≥27 weeks GA.

CONCLUSIONS

Risk factors, cumulative hazard, and time to sROP vary by GA.

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Pediatric Retinal Diseases

Indirect ophthalmoscopy and handheld retinal imaging are the most common and traditional modalities for the evaluation and documentation of the pediatric fundus, especially for pre-verbal children. Optical coherence tomography (OCT) allows for in vivo visualization that resembles histology, and optical coherence tomography angiography (OCTA) allows for non-invasive depth-resolved imaging of the retinal vasculature. Both OCT and OCTA were extensively used and studied in adults, but not in children. The advent of prototype handheld OCT and OCTA have allowed for detailed imaging in younger infants and even neonates in the neonatal care intensive unit with retinopathy of prematurity (ROP). In this review, we discuss the use of OCTA and OCTA in various pediatric retinal diseases, including ROP, familial exudative vitreoretinopathy (FEVR), Coats disease and other less common diseases. For example, handheld portable OCT was shown to detect subclinical macular edema and incomplete foveal development in ROP, as well as subretinal exudation and fibrosis in Coats disease. Some challenges in the pediatric age group include the lack of a normative database and the difficulty in image registration for longitudinal comparison. We believe that technological improvements in the use of OCT and OCTA will improve our understanding and care of pediatric retina patients in the future.

The β3 adrenoceptor in proliferative retinopathies: "Cinderella" steps out of its family shadow

In the retina, hypoxic condition leads to overgrowing leaky vessels resulting in altered metabolic supply that may cause impaired visual function. Hypoxia-inducible factor-1 (HIF-1) is a central regulator of the retinal response to hypoxia by activating the transcription of numerous target genes, including vascular endothelium growth factor, which acts as a major player in retinal angiogenesis. In the present review, oxygen urge by the retina and its oxygen sensing systems including HIF-1 are discussed in respect to the role of the beta-adrenergic receptors (β-ARs) and their pharmacologic manipulation in the vascular response to hypoxia. In the β-AR family, β1- and β2-AR have long been attracting attention because their pharmacology is intensely used for human health, while β3-AR, the third and last cloned receptor is no longer increasingly emerging as an attractive target for drug discovery. Here, β3-AR, a main character in several organs including the heart, the adipose tissue and the urinary bladder, but so far a supporting actor in the retina, has been thoroughly examined in respect to its function in retinal response to hypoxia. In particular, its oxygen dependence has been taken as a key indicator of β3-AR involvement in HIF-1-mediated responses to oxygen. Hence, the possibility of β3-AR transcription by HIF-1 has been discussed from early circumstantial evidence to the recent demonstration that β3-AR acts as a novel HIF-1 target gene by playing like a putative intermediary between oxygen levels and retinal vessel proliferation. Thus, targeting β3-AR may implement the therapeutic armamentarium against neovascular pathologies of the eye.

Systemic Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a vasoproliferative vitreoretinal disorder, is the leading cause of childhood blindness worldwide. Although angiogenic pathways have been the main focus, cytokine-mediated inflammation is also involved in ROP etiology. Herein, we illustrate the characteristics and actions of all cytokines involved in ROP pathogenesis. The two-phase (vaso-obliteration followed by vasoproliferation) theory outlines the evaluation of cytokines in a time-dependent manner. Levels of cytokines may even differ between the blood and the vitreous. Data from animal models of oxygen-induced retinopathy are also valuable. Although conventional cryotherapy and laser photocoagulation are well established and anti-vascular endothelial growth factor agents are available, less destructive novel therapeutics that can precisely target the signaling pathways are required. Linking the cytokines involved in ROP to other maternal and neonatal diseases and conditions provides insights into the management of ROP. Suppressing disordered retinal angiogenesis via the modulation of hypoxia-inducible factor, supplementation of insulin-like growth factor (IGF)-1/IGF-binding protein 3 complex, erythropoietin, and its derivatives, polyunsaturated fatty acids, and inhibition of secretogranin III have attracted the attention of researchers. Recently, gut microbiota modulation, non-coding RNAs, and gene therapies have shown promise in regulating ROP. These emerging therapeutics can be used to treat preterm infants with ROP.

Persistent Vascular Anomalies in Retinopathy of Prematurity Children: Ultra-Widefield Fluorescein Angiography Findings until School Age

Purpose

To investigate vascular abnormalities, including persistent avascular retina (PAR), in a large cohort of patients with regressed or treated retinopathy of prematurity (ROP) through long-term follow-up until school age.

Design

Retrospective large cohort study.

Participants

We included pediatric patients (< 18 years old) with a history of nontreated or treated ROP (treated with either photocoagulation or intravitreal injection [IVI]) and regularly followed up until 2020.

Methods

Upon enrollment, we categorized patients into 4 groups: prematurity, regressed ROP, and IVI and laser treatment ROP groups. All patients had undergone visual acuity examinations, OCT, and ultrawide-field fluorescein angiography.

Main Outcome Measures

Percentage of eyes with PAR (greater than or equal to the area of 2 disc diameters from the ora serrata to vascular termini) and with vascular abnormalities in the peripheral and posterior retina.

Results

In total, we included 187 eyes of 95 patients. The prevalence of PAR was 0%, 33.33%, and 31.65% in eyes in the prematurity, regressed ROP, and IVI treatment groups, respectively (P < 0.0001). There was no significant difference in the percentage of PAR eyes when comparing regressed ROP group (33.33%) with the IVI treatment group (31.65%). At least 1 type of vascular abnormality was noted until school age in all (100%) treated ROP eyes. Although multivariate analysis found a significant association between IVI treatment and PAR (odds ratio: 10.28, 95% confidence interval: 3.29-32.14) until the school age of 6 to 8 years old, there were no stage 3 eyes in the spontaneously regressed group, suggesting that stage 3 ROP in the IVI group could also drive the association.

Conclusions

Approximately one-third of ROP eyes with spontaneous regression or IVI treatment still exhibit PAR when the child reaches school age. Several distinct vascular anomalies at the vascular-avascular juncture and within the vascularized retina can persist in these children. The clinical significance of these anomalies and the decision whether to treat them warrant further investigation to optimize their outcomes.

Financial Disclosures

The authors have no proprietary or commercial interest in any materials discussed in this article.

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