Update in the Treatment of Retinopathy of Prematurity

Clinical Risk Factors for Retinopathy of Prematurity Reactivation after Intravitreal Antivascular Endothelial Growth Factor Injection

OBJECTIVE

To assess the rate and risk factors for reactivation of retinopathy of prematurity (ROP) after intravitreal injection (IVI) of antivascular endothelial growth factor (VEGF) agents.

STUDY DESIGN

Infants who received IVI therapy between 2017 and 2022 were enrolled and divided into 2 groups: those with and without ROP reactivation. Information on ROP variables and patient variables were analyzed using multivariable logistic regression.

RESULTS

A total of 114 infants with 223 eyes were enrolled in the study. The ROP reactivation rate was 11.4% of infants (9.9% of eyes). The mean duration of reactivation was 84 ± 45 days. Among the 223 eyes treated with IVI, reactivation rates were 6% for bevacizumab, 13.9% for aflibercept, and 22.2% for ranibizumab. A multivariable regression model showed that ranibizumab was an independent risk factor (OR 11.4, P = .008) for reactivation. Other risk factors included infants with periventricular leukomalacia (OR 13.8, P = .003), patent ductus arteriosus ligation (OR 10.7, P = .032), and infants who still required invasive mechanical ventilation on the day of IVI therapy (OR 7.0, P = .018).

CONCLUSIONS

All anti-VEGF agents carry a risk of ROP reactivation, with the risk being greater with ranibizumab 0.25 mg than with bevacizumab 0.625 mg. Reactivation of ROP should be assessed vigilantly, especially in those infants with increased risks. Future research to determine the optimal anti-VEGF selection and dosage in high-risk infants is warranted.

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.

Macular Optical Coherence Tomography Angiographic Study in Children with a History of Prematurity: A Systematic Review and Meta-Analysis

PURPOSE

to assess the changes in the macular structure in children with history of prematurity and to find the relationship between retinopathy of prematurity (ROP) treatment and macular ultrastructural changes found in optical coherence tomography angiography study.

METHODS

a search for identifying relevant studies published in English using PubMed, Google Scholar, Scopus, and Web of Science databases from the date of inception to 21 October 2022 was conducted. Studies were included if their subjects were >5 years and used Optovue device for imaging. Twelve studies were included for final analysis. After extracting data, foveal avascular zone (FAZ), vessel density (VD) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) in the foveal and parafoveal area, central foveal thickness (CFT), and visual acuity (VA) were compared between the study groups.

RESULTS

in individual who were born full term the FAZ was significantly larger. The SCP and DCP VD was significantly higher in children with history of ROP treatment. Superficial parafoveal VD was significantly lower in term children than both treated groups. The CFT was significantly higher in children with history of ROP (treated and untreated) than the terms. VA was lower in laser and IVI treated children than terms and it was related to the changes in CFT, foveal superficial and deep VD and FAZ area.

CONCLUSIONS

Patients with a history of ROP treatment have a significantly greater CFT, higher VD of foveal SCP and DCP, and lower VA than the term-born children. Furthermore, the FAZ is negatively associated with VA and CFT.

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.

Current management of surgical neonates: is it optimal or do we need to improve? A national survey of the Italian Society of Neonatology

PURPOSE

Few guidelines exist for the perioperative management (PM) of neonates with surgical conditions (SC). This study examined the current neonatal PM in Italy.

METHODS

We invited 51 neonatal intensive care units with pediatric surgery in their institution to participate in a web-based survey. The themes included (1) the involvement of the neonatologist during the PM; (2) the spread of bedside surgery (BS); (3) the critical issues concerning the neonatal PM in operating rooms (OR) and the actions aimed at improving the PM.

RESULTS

Response rate was 82.4%. The neonatologist is involved during the intraoperative management in 42.9% of the responding centers (RC) and only when the surgery is performed at the patient's bedside in 50.0% of RCs. BS is reserved for extremely preterm (62.5%) or clinically unstable (57.5%) infants, and the main barrier to its implementation is the surgical-anesthesiology team's preference to perform surgery in a standard OR (77.5%). Care protocols for specific SC are available only in 42.9% of RCs.

CONCLUSION

Some critical issues emerged from this survey: the neonatologist involvement in PM, the spread of BS, and the availability of specific care protocols need to be implemented to optimize the care of this fragile category of patients.

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.

Propranolol: a new pharmacologic approach to counter retinopathy of prematurity progression

Despite the evident progress in neonatal medicine, retinopathy of prematurity (ROP) remains a serious threat to the vision of premature infants, due to a still partial understanding of the mechanisms underlying the development of this disease and the lack of drugs capable of arresting its progression. Although ROP is a multifactorial disease, retinal vascularization is strictly dependent on oxygen concentration. The exposition of the retina of a preterm newborn, still incompletely vascularized, to an atmosphere relatively hyperoxic, as the extrauterine environment, induces the downregulation of proangiogenic factors and therefore the interruption of vascularization (first ischemic phase of ROP). However, over the following weeks, the growing metabolic requirement of this ischemic retina produces a progressive hypoxia that specularly promotes the surge of proangiogenic factors, finally leading to proliferative retinopathy (second proliferative phase of ROP). The demonstration that the noradrenergic system is actively involved in the coupling between hypoxia and the induction of vasculogenesis paved the way for a pharmacologic intervention aimed at counteracting the interaction of noradrenaline with specific receptors and consequently the progression of ROP. A similar trend has been observed in infantile hemangiomas, the most common vascular lesion of childhood induced by pre-existing hypoxia, which shares similar characteristics with ROP. The fact that propranolol, an unselective antagonist of β1/2 adrenoceptors, counteracts the growth of infantile hemangiomas, suggested the idea of testing the efficacy of propranolol in infants with ROP. From preclinical studies, ongoing clinical trials demonstrated that topical administration of propranolol likely represents the optimal approach to reconcile its efficacy and maximum safety. Given the strict relationship between vessels and neurons, recovering retinal vascularization with propranolol may add further efficacy to prevent retinal dysfunction. In conclusion, the strategy of contrasting precociously the progression of the disease appears to be more advantageous than the current wait-and-see therapeutic approach, which instead is mainly focused on avoiding retinal detachment.

Oxidative stress in the eye and its role in the pathophysiology of ocular diseases

Oxidative stress occurs through an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense mechanisms of cells. The eye is particularly exposed to oxidative stress because of its permanent exposure to light and due to several structures having high metabolic activities. The anterior part of the eye is highly exposed to ultraviolet (UV) radiation and possesses a complex antioxidant defense system to protect the retina from UV radiation. The posterior part of the eye exhibits high metabolic rates and oxygen consumption leading subsequently to a high production rate of ROS. Furthermore, inflammation, aging, genetic factors, and environmental pollution, are all elements promoting ROS generation and impairing antioxidant defense mechanisms and thereby representing risk factors leading to oxidative stress. An abnormal redox status was shown to be involved in the pathophysiology of various ocular diseases in the anterior and posterior segment of the eye. In this review, we aim to summarize the mechanisms of oxidative stress in ocular diseases to provide an updated understanding on the pathogenesis of common diseases affecting the ocular surface, the lens, the retina, and the optic nerve. Moreover, we discuss potential therapeutic approaches aimed at reducing oxidative stress in this context.

The impact after 20 years of an early detection program for severe retinopathy of prematurity in a Latin American city

Purpose

To evaluate the effects of long-standing early detection program in the incidence and trends of severe retinopathy of prematurity (ROP) in Cali, Colombia.

Methods

This was a retrospective cohort study of infants included in an ROP prevention, early detection, and prompt treatment program, from January 01, 2002, to December 31, 2021 (20 years). Infants with gestational age (GA) <37 weeks or birth weight (BW) <2000 g and those with known ROP risk factors were screened. The incidence of severe ROP was calculated, and the average annual percent change (AAPC) was estimated through a joinpoint model.

Results

16,580 infants were screened, with an average GA and BW of 31.4 ± 2.8 weeks and 1526.5 ± 56.7 g, respectively. The incidence of severe ROP was 2.69% (446 cases, 95% confidence interval [95%CI]: 2.45%; 2.95%), with an average annual decrease of - 14% (AAPC, 95%CI: -16.3%; -11.6%) from 13.6% in 2002 to 0.7% in 2021. In infants with GA <32 weeks, the incidence was 5.21%. A significant reduction in the risk of ROP was observed with increasing GA and BW (P < 0.05). Among the cases with severe ROP, 6.5% (29/446) had a GA ≥32 weeks with a maximum of 37 weeks; only 0.4% (2/446) of the detected infants had a BW >2000 g.

Conclusion

Awareness and screening as part of the early detection program to prevent ROP has shown a significant decline in the incidence of severe ROP over time. Screening infants with GA <32 weeks or BW <2000 g and preterm infants (<37 weeks) with risk factors may be a feasible decision for resource optimization.

Identification and validation of lactate metabolism-related genes in oxygen-induced retinopathy

Retinopathy of Prematurity (ROP) is a multifactorial disease characterized by abnormal retinal vascular growth in premature infants, which is one of the leading causes of childhood blindness. Lactic acid metabolism may play an imperative role in the development of ROP, but there are still few relevant studies. Our team use a dataset GSE158799 contained 284 genes in 3 P17_OIR mice and 3 P30_OIR mice to identify 41 potentially differentially expressed lactate metabolism-related genes (LMRGs) related to ROP. Then through bioinformatics analysis, we strive to reveal the interaction, the enriched pathways and the immune cell infiltration among these LMRGs, and predict their functions and internal mechanisms. These DEGs may regulate lactate metabolism, leading to the changes of metabolism and immunity, thereby inducing the development of ROP. Our results will expand our understanding of the intrinsic mechanism of ROP and may be helpful for the directions for treatment of ROP in the future.

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.

Twelve-year outcomes of bedside laser photocoagulation for severe retinopathy of prematurity

Purpose

The purpose of this study is to evaluate the 12-year outcomes of bedside laser photocoagulation (LP) for severe retinopathy of prematurity (ROP) under sedation combined with ocular surface anesthesia in neonatal intensive care units (NICU).

Design

The study is a retrospective case series.

Methods

Infants treated with bedside LP for severe ROP from April 2009 to September 2021 were included. All LP treatments were performed under sedation and surface anesthesia at the bedside in NICU. Data were recorded for clinical and demographic characteristics, total laser spots, duration of treatment, proportion of total regression of ROP, proportion of recurrence, and adverse events.

Results

A total of 364 infants (715 eyes) were included, with a mean gestational age of 28.6 ± 2.4 weeks (range: 22.6-36.6 weeks) and a mean birth weight of 1,156.0 ± 339.0 g (range: 480-2,200 g). The mean number of laser spots was 832 ± 469, and the mean duration of treatment was 23.5 ± 5.3 min per eye. Of all the eyes, 98.3% responded to LP with complete regression of ROP. ROP recurred in 15 (2.1%) eyes after the initial LP. Additional LP was performed in seven (1.0%) eyes. No patient exhibited mistaken LP of other ocular tissues, and there were no serious ocular adverse effects. None of them needed endotracheal intubation.

Conclusions

Bedside LP treatment is effective and safe for premature infants with severe ROP under sedation and surface anesthesia in NICU, especially for infants whose general condition is unstable and not suitable for transport.

[Protective effect of melatonin against oxygen-induced retinopathy: a study based on the HMGB1/NF-κB/NLRP3 axis]

OBJECTIVES

To study the protective effect of melatonin (Mel) against oxygen-induced retinopathy (OIR) in neonatal mice and the role of the HMGB1/NF-κB/NLRP3 axis.

METHODS

Neonatal C57BL/6J mice, aged 7 days, were randomly divided into a control group, a model group (OIR group), and a Mel treatment group (OIR+Mel group), with 9 mice in each group. The hyperoxia induction method was used to establish a model of OIR. Hematoxylin and eosin staining and retinal flat-mount preparation were used to observe retinal structure and neovascularization. Immunofluorescent staining was used to measure the expression of proteins and inflammatory factors associated with the HMGB1/NF-κB/NLRP3 axis and lymphocyte antigen 6G. Colorimetry was used to measure the activity of myeloperoxidase.

RESULTS

The OIR group had destruction of retinal structure with a large perfusion-free area and neovascularization, while the OIR+Mel group had improvement in destruction of retinal structure with reductions in neovascularization and perfusion-free area. Compared with the control group, the OIR group had significant increases in the expression of proteins and inflammatory factors associated with the HMGB1/NF-κB/NLRP3 axis, the expression of lymphocyte antigen 6G, and the activity of myeloperoxidase (P<0.05). Compared with the OIR group, the OIR+Mel group had significant reductions in the above indices (P<0.05). Compared with the control group, the OIR group had significant reductions in the expression of melatonin receptors in the retina (P<0.05). Compared with the OIR group, the OIR+Mel group had significant increases in the expression of melatonin receptors (P<0.05).

CONCLUSIONS

Mel can alleviate OIR-induced retinal damage in neonatal mice by inhibiting the HMGB1/NF-κB/NLRP3 axis and may exert an effect through the melatonin receptor pathway.

Harnessing the therapeutic potential of the stem cell secretome in neonatal diseases

Preterm birth and intrapartum related complications account for a substantial amount of mortality and morbidity in the neonatal period despite significant advancements in neonatal-perinatal care. Currently, there is a noticeable lack of curative or preventative therapies available for any of the most common complications of prematurity including bronchopulmonary dysplasia, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia and retinopathy of prematurity or hypoxic-ischemic encephalopathy, the main cause of perinatal brain injury in term infants. Mesenchymal stem/stromal cell-derived therapy has been an active area of investigation for the past decade and has demonstrated encouraging results in multiple experimental models of neonatal disease. It is now widely acknowledged that mesenchymal stem/stromal cells exert their therapeutic effects via their secretome, with the principal vector identified as extracellular vesicles. This review will focus on summarizing the current literature and investigations on mesenchymal stem/stromal cell-derived extracellular vesicles as a treatment for neonatal diseases and examine the considerations to their application in the clinical setting.

Hematologic Risk Factors for the Development of Retinopathy of Prematurity—A Retrospective Study

(1) Background: Retinopathy of prematurity (ROP) can cause severe visual impairment or even blindness. We aimed to assess the hematological risk factors that are associated with different stages of ROP in a cohort of preterm newborns, and to compare the clinical characteristics and therapeutic interventions between groups. (2) Methods: This retrospective study included 149 preterm newborns from a tertiary maternity hospital in Romania between January 2018 and December 2018, who were segregated into: Group 1 (with ROP, n = 59 patients), and Group 2 (without ROP, n = 90 patients). The patients that were affected by ROP were subsequently divided into the following subgroups: Subgroup 1 (Stage 1, n = 21), Subgroup 2 (Stage 2, n = 35), and Subgroup 3 (Stage 3, n = 25). The associations were analyzed using multivariate logistic regression and sensitivity analysis. (3) Results: Platelet mass indexes (PMI) that were determined in the first, seventh, and tenth days of life were significantly associated with Stage 1 ROP. PMI determined in the first day of life was also significantly associated with Stage 2 ROP. The sensitivity and specificity of these parameters were modest, ranging from 44 to 57%, and 59 to 63%. (4) Conclusions: PMI has a modest ability to predict the development of ROP.

Retinopathy of prematurity: A review of pathophysiology and signaling pathways

Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the retina and a leading cause of visual impairment and childhood blindness worldwide. The disease is characterized by an early stage of retinal microvascular degeneration, followed by neovascularization that can lead to subsequent retinal detachment and permanent visual loss. Several factors play a key role during the different pathological stages of the disease. Oxidative and nitrosative stress and inflammatory processes are important contributors to the early stage of ROP. Nitric oxide synthase and arginase play important roles in ischemia/reperfusion-induced neurovascular degeneration. Destructive neovascularization is driven by mediators of the hypoxia-inducible factor pathway, such as vascular endothelial growth factor and metabolic factors (succinate). The extracellular matrix is involved in hypoxia-induced retinal neovascularization. Vasorepulsive molecules (semaphorin 3A) intervene preventing the revascularization of the avascular zone. This review focuses on current concepts about signaling pathways and their mediators, involved in the pathogenesis of ROP, highlighting new potentially preventive and therapeutic modalities. A better understanding of the intricate molecular mechanisms underlying the pathogenesis of ROP should allow the development of more effective and targeted therapeutic agents to reduce aberrant vasoproliferation and facilitate physiological retinal vascular development.

The Determinative Role of Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a neonatal disease corresponding to vision impairment and blindness. Utilizing the pathogenesis of ROP and the risk factors affecting its progression can help prevent and reduce its incidence and lead to the emergence and development of new treatment strategies. Factors influencing retinopathy include growth and inflammatory factors that play an essential role in the pathogenesis of the ROP. This review summarizes the most critical factors in the pathogenesis of ROP.

Maternally expressed gene 3 regulates retinal neovascularization in retinopathy of prematurity

The mouse model of oxygen induced retinopathy is suitable for the study of various retinal neovascularization diseases, including retinopathy of prematurity. The maternally expressed gene 3 (MEG3) has been demonstrated to have an inhibitory effect on diabetic retinopathy. In this study, we investigated the role of MEG3 overexpression in oxygen-induced retinopathy in mice. The results showed that MEG3 overexpression effectively inhibited the production of retinal neovascularization in oxygen-induced retinopathy mice. It acts by down-regulating the expression of phosphoinositide 3-kinase, serine/threonine kinase, and vascular endothelial growth factor and pro-inflammatory factors. MEG3 overexpression lentivirus has a future as a new method for the clinical treatment of retinopathy of prematurity. The animal experiments were approved by the Animal Ethics Committee of Shengjing Hospital of China Medical University, China (approval No. 2016PS074K) on February 25, 2016.

Etanercept as a TNF-alpha inhibitor depresses experimental retinal neovascularization

PURPOSE

The formation of retinal neovascularization (RNV) is the primary pathological process underlying retinopathy of prematurity (ROP). Previous studies have shown that inflammatory factors are related to the formation of RNV. Tumor necrosis factor-α (TNF-α), as an important factor in the inflammatory response, is involved in the regulation of RNV formation. However, the mechanism through which TNF-α inhibition reduces RNV formation is not fully clarified. Therefore, the purpose of this study was to explore the effect of etanercept, an inhibitor of TNF-α, on RNV, and its possible mechanism.

METHODS

In vivo, an oxygen-induced retinopathy (OIR) mouse model was used to determine the effect of etanercept on the formation of RNV by performing immunostaining. The effect of etanercept on tumor necrosis factor receptor-associated factor 2 (TRAF2), pro-angiogenic-related factors, and pro/anti-inflammatory factors in OIR mice was assessed by real-time PCR and Western blotting. In vitro, the effect of etanercept on TNF-α-induced human retinal microvascular endothelial cell tube formation was evaluated by tube formation assays, and the potential mechanism of etanercept was explored by Western blotting.

RESULTS

In vivo, etanercept reduced the area of RNV and decreased the expression of TRAF2 in the OIR mouse model. Etanercept also suppressed the expression of several pro-angiogenic factors and regulated the pro/anti-inflammatory factors. In vitro, etanercept reduced endothelial cell tube formation by inhibiting activation of the NF-κB signaling pathway.

CONCLUSION

Etanercept can regulate pro/anti-inflammatory factors and reduce the expression of pro-angiogenic factors by inhibiting NF-κB phosphorylation, thereby reducing RNV formation.