Advances in understanding and management of retinopathy of prematurity

[Smartphone-based fundus imaging: applications and adapters]

BACKGROUND

Smartphone-based fundus imaging (SBFI) is an innovative and low-cost alternative for color fundus photography. Since the first reports on this topic more than 10 years ago a large number of studies on different adapters and clinical applications have been published.

OBJECTIVE

The aim of this review article is to provide an overview on the development of SBFI and adapters and clinical applications published so far.

MATERIAL AND METHODS

A literature search was performed using the MEDLINE and Science Citation Index Expanded databases without time restrictions.

RESULTS

Overall, 11 adapters were included and compared in terms of exemplary image material, field of view, acquisition costs, weight, software, application range, smartphone compatibility and certification. Previously published SBFI applications are screening for diabetic retinopathy, glaucoma and retinopathy of prematurity as well as the application in emergency medicine, pediatrics and medical education/teaching. Image quality of conventional retinal cameras is in general superior to SBFI. First approaches on automatic detection of diabetic retinopathy through SBFI are promising and the use of automatic image processing algorithms enables the generation of wide-field image montages.

CONCLUSION

SBFI is a versatile, mobile, low-cost alternative to conventional equipment for color fundus photography. In addition, it facilitates the delegation of ophthalmological examinations to assistance personnel in telemedical settings, could simplify retinal documentation, improve teaching, and improve ophthalmological care, particularly in countries with low and middle incomes.

FACTORS ASSOCIATED WITH REACTIVATION AFTER INTRAVITREAL BEVACIZUMAB OR RANIBIZUMAB THERAPY IN INFANTS WITH RETINOPATHY OF PREMATURITY

PURPOSE

To investigate the efficacy and risk factors of intravitreal antivascular endothelial growth factor injection (anti-VEGF therapy) for retinopathy of prematurity (ROP).

METHODS

We retrospectively reviewed 80 consecutive eyes of 43 patients with Type 1 ROP or worse who received anti-VEGF therapy during January 2012-February 2018. Patients were divided into those who were injected with 0.25 mg of bevacizumab (IVB group, 37 eyes) and 0.25 mg of ranibizumab (IVR group, 43 eyes). Serum VEGF concentrations of 18 patients were measured before and after IVR.

RESULTS

Antivascular endothelial growth factor injection therapy reduced ROP activity in all eyes; however, 14 eyes (17.5%) exhibited reactivation. The reactivation rates of the IVB and IVR groups were 13.5% and 20.9%, respectively (P = 0.556). Multivariate logistic regression analysis showed that postmenstrual age ≤35 weeks at anti-VEGF therapy (P = 0.014) and aggressive posterior ROP (P = 0.044) was significantly associated with reactivation. Serum VEGF was significantly suppressed at Days 1 (P < 0.001) and 7 (P = 0.012) after IVR and returned to the preinjection level by Day 14 (P = 0.210).

CONCLUSION

Both IVR and IVB seemed effective in reducing ROP activity. Reactivation after anti-VEGF therapy may be associated with younger postmenstrual age at anti-VEGF therapy and aggressive posterior ROP.

Variability of Retinal Oxygen Metrics in Healthy and Diabetic Subjects

Purpose

Previous studies have reported alterations in total retinal blood flow (TRBF), oxygen delivery (DO2), oxygen metabolism (MO2), and oxygen extraction fraction (OEF) due to retinal diseases. The purposes of the current study were to determine variabilities and establish normal confidence intervals (CIs) for these metrics.

Methods

A total of 22 healthy and 14 diabetic subjects participated in the study. Retinal vascular oxygen saturation (SO2) and TRBF were measured by oximetry and Doppler optical coherence tomography, respectively. DO2, MO2, and OEF were calculated from SO2 and TRBF measurements. Means, standard deviations (SDs), and CIs of metrics were determined in healthy subjects. Intra-visit variability was determined by the mean SDs of repeated measurements. Inter-visit variability was determined by the difference of measurements between two visits.

Results

TRBF was 44 ± 15 µL/min (95% CI, 37-51) in healthy subjects. Intra-visit variabilities of TRBF were 5 µL/min and 6 µL/min in healthy and diabetic subjects, respectively. Inter-visit variability of TRBF was 3 µL/min in diabetic subjects. DO2, MO2, and OEF were 8.3 ± 2.9 µLO2/min (95% CI, 7.0-9.6), 3.2 ± 0.9 µLO2/min (95% CI, 2.8-3.6), and 0.40 ± 0.08 (95% CI, 0.36-0.43), respectively, in healthy subjects. Inter-visit variabilities of DO2, MO2, and OEF were 0.6 µLO2/min, 0.1 µLO2/min, and 0.03, respectively, in diabetic subjects.

Conclusions

The findings established variabilities and normal baselines for TRBF, DO2, MO2, and OEF measurements in a small cohort of subjects.

Translational Relevance

The variability and normal baselines of retinal oxygen metrics may be useful for diagnosing and monitoring patients with retinal diseases.

VEGFR1 signaling in retinal angiogenesis and microinflammation

Five vascular endothelial growth factor receptor (VEGFR) ligands (VEGF-A, -B, -C, -D, and placental growth factor [PlGF]) constitute the VEGF family. VEGF-A binds VEGF receptors 1 and 2 (VEGFR1/2), whereas VEGF-B and PlGF only bind VEGFR1. Although much research has been conducted on VEGFR2 to elucidate its key role in retinal diseases, recent efforts have shown the importance and involvement of VEGFR1 and its family of ligands in angiogenesis, vascular permeability, and microinflammatory cascades within the retina. Expression of VEGFR1 depends on the microenvironment, is differentially regulated under hypoxic and inflammatory conditions, and it has been detected in retinal and choroidal endothelial cells, pericytes, retinal and choroidal mononuclear phagocytes (including microglia), Müller cells, photoreceptor cells, and the retinal pigment epithelium. Whilst the VEGF-A decoy function of VEGFR1 is well established, consequences of its direct signaling are less clear. VEGFR1 activation can affect vascular permeability and induce macrophage and microglia production of proinflammatory and proangiogenic mediators. However the ability of the VEGFR1 ligands (VEGF-A, PlGF, and VEGF-B) to compete against each other for receptor binding and to heterodimerize complicates our understanding of the relative contribution of VEGFR1 signaling alone toward the pathologic processes seen in diabetic retinopathy, retinal vascular occlusions, retinopathy of prematurity, and age-related macular degeneration. Clinically, anti-VEGF drugs have proven transformational in these pathologies and their impact on modulation of VEGFR1 signaling is still an opportunity-rich field for further research.

Comparison of Outcomes Between Combined Sparing Laser Photocoagulation and Intravitreal Bevacizumab Treatment Versus Conventional Laser Photocoagulation in Aggressive Posterior Retinopathy of Prematurity

PURPOSE

To report the clinical outcomes of combined sparing laser photocoagulation and intravitreal bevacizumab treatment compared to conventional laser photocoagulation for the treatment of aggressive posterior retinopathy of prematurity (APROP).

METHODS

A medical chart review was performed on all consecutive eyes with APROP that were treated with conventional laser photocoagulation or laser photocoagulation and intravitreal bevacizumab (IVB) injection between July 2019 and August 2020. The data were recorded for time to reversal of plus disease, time to total regression of retinopathy of prematurity (ROP) after intervention, total laser spots and area, proportion of eyes with satisfactory anatomical outcomes, and adverse events. Outcomes of the two groups were compared.

RESULTS

Sixteen eyes of 8 infants with APROP were included in the analysis. Eight eyes of 4 infants received combined sparing laser photocoagulation and IVB treatment, and 8 eyes of 4 infants received conventional laser photocoagulation. All 8 eyes in the combined treatment group and 6 of 8 eyes in the conventional treatment group showed regression of ROP with a satisfactory anatomical outcome. The average time to total regression of ROP was 34 days in the combined treatment group and 56 days in the conventional treatment group (P = .005). The number of laser spots was significantly lower in the combined treatment group (P = .03).

CONCLUSIONS

Combined sparing laser photocoagulation and IVB treatment for eyes with APROP achieved ROP regression twice as fast, had fewer laser spots, and had a satisfactory anatomical outcome in comparison to conventional laser photocoagulation. [J Pediatr Ophthalmol Strabismus. 2021;58(5):292-297.].

Adenosine A2A receptor antagonism protects against hyperoxia-induced retinal vascular loss via cellular proliferation

Retinopathy of prematurity (ROP) remains one of the major causes of blindness in children worldwide. While current ROP treatments are mostly disruptive to reduce proliferative neovascularization by targeting the hypoxic phase, protection against early hyperoxia-induced retinal vascular loss represents an effective therapeutic window, but no such therapeutic strategy is available. Built upon our recent demonstration that the protection against oxygen-induced retinopathy by adenosine A_2A receptor (A_2A R) antagonists is most effective when administered at the hyperoxia (not hypoxic) phase, we here uncovered the cellular mechanism underlying the A_2A R-mediated protection against early hyperoxia-induced retinal vascular loss by reversing the inhibition of cellular proliferation via possibly multiple signaling pathways. Specifically, we revealed two distinct stages of the hyperoxia phase with greater cellular proliferation and apoptosis activities and upregulation of adenosine signaling at postnatal 9 day (P9) but reduced cellular activities and adenosine-A_2A R signaling at P12. Importantly, the A_2A R-mediated protection at P9 was associated with the reversal of hyperoxia-induced inhibition of progenitor cells at the peripheral retina at P9 and of retinal endothelial proliferation at P9 and P12. The critical role of cellular proliferation in the hyperoxia-induced retinal vascular loss was validated by the increased avascular areas by siRNA knockdown of the multiple signaling molecules involved in modulation of cellular proliferation, including activin receptor-like kinase 1, DNA-binding protein inhibitor 1, and vascular endothelial growth factor-A.

[Pathogenetically oriented approach to prevention of retinopathy of prematurity (experimental study)]

Intraperitoneal injections of exogenous melatonin during the development of the retinal vascular system in experimental rats has been shown in a number of experimental studies on the model of EROP to prevent the appearance of histological signs of the development of experimental retinopathy of prematurity (EROP), stabilize the blood-retinal barrier and have a pronounced antioxidant effect, but pathogenetic basis for these phenomena hasn't been studied.

PURPOSE

To study the influence mechanism of melatonin and its analogues on the development of EROP at the preclinical stage of the pathological process to substantiate new approaches to prevention of ROP.

MATERIAL AND METHODS

The study included 42 Wistar rat pups (84 eyes) divided into 6 groups: control group, experimental group (rat pups with EROP), experimental groups who underwent injections of melatonin and its analogues K-148, AL-3, K-096. The pups were euthanized on day 7 (4-5 pups from each group at each study period), binocular enucleation was performed, and the content of hypoxia-induced factor1α (HIF-1α) and VEGF-A was determined in retinal samples.

RESULTS

The intraperitoneal injections of melatonin and its analogs led to a significant decrease in the level of HIF-1α and VEGF-A in the retina of the rat pups of the experimental group until the beginning of pathological vasoproliferation.

CONCLUSION

Melatonin and its analogues are able to prevent the development of EROP by reducing the level of angiogenic factors in the retina of rat pups at the stage of existing avascular zones, which allows for them to be considered as a new promising approach to preventing the development of ROP.

Aggressive posterior retinopathy of prematurity: a review on current understanding

A review of literature was performed, focused on the etiopathogenesis of aggressive posterior retinopathy of prematurity (APROP), the characteristic and atypical clinical features, management strategies, anatomical and visual outcomes. Characteristically APROP has zone I/posterior zone II involvement with prominent plus disease, featureless junction, large vascular loops, flat extra-retinal fibrovascular proliferation, and a rapidly progressive course. The risk factors for APROP are extreme prematurity (birth weight ≤1000 gram and/or gestational age ≤28 weeks), dysregulated oxygen supplementation, intrauterine growth retardation, sepsis, and thrombocytopenia. The uncommon presentations include small zone I disease, a hybrid disease with additional ridge tissue, and APROP in bigger babies with birth weight greater than 1500 g. Laser photocoagulation role is limited by the resultant visual field loss and high refractive error. Although anti-vascular endothelial growth factor injection allows peripheral retinal vascularization; reactivation of disease, systemic absorption of the drug and long-term safety are the chief concerns. Early vitrectomy is required when tractional retinal detachment develops. The visual outcome depends upon the morphology and vascular development of the macula. With the limited yet emerging new understanding of the pathophysiology, a multifaceted rational and individualized treatment strategy is suggested for APROP. Best practices in neonatal intensive care may prevent the occurrence of APROP. Further studies need to be performed for the prevention and safe, effective management of APROP.

Caffeine and Its Neuroprotective Role in Ischemic Events: A Mechanism Dependent on Adenosine Receptors

Ischemia is characterized by a transient, insufficient, or permanent interruption of blood flow to a tissue, which leads to an inadequate glucose and oxygen supply. The nervous tissue is highly active, and it closely depends on glucose and oxygen to satisfy its metabolic demand. Therefore, ischemic conditions promote cell death and lead to a secondary wave of cell damage that progressively spreads to the neighborhood areas, called penumbra. Brain ischemia is one of the main causes of deaths and summed with retinal ischemia comprises one of the principal reasons of disability. Although several studies have been performed to investigate the mechanisms of damage to find protective/preventive interventions, an effective treatment does not exist yet. Adenosine is a well-described neuromodulator in the central nervous system (CNS), and acts through four subtypes of G-protein-coupled receptors. Adenosine receptors, especially A₁ and A_2A receptors, are the main targets of caffeine in daily consumption doses. Accordingly, caffeine has been greatly studied in the context of CNS pathologies. In fact, adenosine system, as well as caffeine, is involved in neuroprotection effects in different pathological situations. Therefore, the present review focuses on the role of adenosine/caffeine in CNS, brain and retina, ischemic events.

Outcome of 532 nm Nd:YAG laser photocoagulation in retinopathy of prematurity from a referral center

Clinical relevance: Retinopathy of prematurity is a preventable blinding disorder worldwide. Laser photocoagulation is said to be the gold standard care of treatment. However, various factors are known to affect the outcome.Background: The purpose of this study was to analyse the risk factors in patients with laser treatment requiring retinopathy of prematurity (ROP) and the outcome of 532 nm Nd:YAG laser photocoagulation (LP).Methods: Patients who underwent LP for ROP at a tertiary referral centre between January 2012 and January 2019 were enrolled. Those who were born and followed-up at the institution of the authors were in Group 1 and those who were born and followed-up elsewhere and referred to the authors for treatment were in Group 2. The clinical features, gestational ages, birth weights, and data regarding the treatment were retrospectively reviewed. The need for pars plana vitrectomy was taken as a poor outcome.Results: The mean gestational age and birth rate was 26.7 ± 1.9 weeks and 927.2 ± 263.5 grams, respectively, in Group 1 (57 infants, 111 eyes); and 28.5 ± 2.5 weeks and 1174.8 ± 385 grams, respectively, in Group 2 (66 infants, 131eyes) (p < 0.001 for both). The extent of the disease (p < 0.001), the zone of the disease (p = 0.002), and the timing of LP (p < 0.001) were significantly different between groups. In the whole cohort, the zone (p = 0.006) and stage (p < 0.001) of the disease, aggressive posterior disease (p = 0,009), and tunica vasculosa lentis were found to significantly interfere with the outcome.Conclusion: Eyes with more severe disease undergoing timely treatment and eyes with less severe disease undergoing delayed management had similar prognosis. A favourable outcome was obtained with 532 nm green laser in ROP.

Potential Effects of Nutraceuticals in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), the most common cause of childhood blindness, is a hypoxia-induced eye disease characterized by retinal neovascularization. In the normal retina, a well-organized vascular network provides oxygen and nutrients as energy sources to maintain a normal visual function; however, it is disrupted when pathological angiogenesis is induced in ROP patients. Under hypoxia, inadequate oxygen and energy supply lead to oxidative stress and stimulate neovasculature formation as well as affecting the function of photoreceptors. In order to meet the metabolic needs in the developing retina, protection against abnormal vascular formation is one way to manage ROP. Although current treatments provide beneficial effects in reducing the severity of ROP, these invasive therapies may also induce life-long consequences such as systemic structural and functional complications as well as neurodevelopment disruption in the developing infants. Nutritional supplements for the newborns are a novel concept for restoring energy supply by protecting the retinal vasculature and may lead to better ROP management. Nutraceuticals are provided in a non-invasive manner without the developmental side effects associated with current treatments. These nutraceuticals have been investigated through various in vitro and in vivo methods and are indicated to protect retinal vasculature. Here, we reviewed and discussed how the use of these nutraceuticals may be beneficial in ROP prevention and management.

Operational guidelines for ROP in India: A summary

Retinopathy of Prematurity (ROP) is a potentially blinding disease of the eye that can affect infants born four or more weeks preterm and have received intensive neonatal care. ROP is a dynamic, time-bound disease that is not present at birth. Preventing visual loss from ROP in India requires scaling up services for screening and treatment for ROP to match the exponential growth in neonatal intensive care in India and other low- and middle-income countries. Operational guidelines for prevention of visual loss from ROP will facilitate rapid scale up of services, by identifying key players and their roles and responsibility in the Indian context. The guidelines recommend broad eligibility criteria for screening (gestational age ≤34 weeks, birth weight ≤2000 gms) as the special newborn care unit (SNCU) have varying quality of neonatal care. Treatment is based on the early treatment for retinopathy of prematurity (ET-ROP) study treatment criteria. The screening criteria could be revisited when more contextual evidence on the risk of ROP is available in India.

Early management of sight threatening retinopathy in incontinentia pigmenti

BACKGROUND

Early blindness secondary to incurable retinal detachment is one of the main complications of incontinentia pigmenti (IP). The efficiency of ophthalmological management for preventing such evolution has not been proven. The objective of this retrospective study was to report a screening and treatment strategy of the vascular retinopathy in newborns and infants with IP.

RESULTS

All files of patients diagnosed with IP within the two first months of life in a single tertiary referral center, between 2010 and 2015, were retrospectively included. The minimum follow-up duration was three years. Patients had undergone systematic indirect ophthalmoscopy examination, looking for signs of peripheric retinal vasculopathy, according to a standardized schedule: at diagnosis, at age 1, 2, 3, 6, 9, 12, 18 and 24 months, and then once a year. Urgent laser therapy was performed under anesthesia in case of signs of retinal ischemia. Nineteen children files (17 girls) were studied. Median age at IP diagnosis was 1 day [0-44]; median age at first retinal evaluation was 25 days. Retinal manifestations occurred in 7 patients (n = 10/38 eyes, 26.3%); they were diagnosed at median age 19 days [3-59]. These patients underwent one or two ablative session per eye (mean 1.7, median 2), under general anaesthesia. No retinal detachment or fold occurred during the follow-up (median 6 years [3-9.8]).

CONCLUSION

Ocular screening should be performed in all cases of IP as soon as possible after diagnosis. A strict ophthalmological monitoring and prophylactic treatment of retinal vasculopathy can efficiently prevent the early blinding complications of the disease.

Effect and mechanism of the long noncoding RNA MALAT1 on retinal neovascularization in retinopathy of prematurity

AIMS

The most typical pathological manifestation of retinopathy of prematurity (ROP) is Retinal neovascularization (RNV). Long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been reported to mediate angiogenesis. Our experiment aimed to research the effect and mechanism of the MALAT1 on RNV in ROP.

MAIN METHODS

C57 mice was used to establish oxygen-introduced retinopathy (OIR), and divided into control, hyperoxia, hyperoxia control siRNA, and hyperoxia MALAT1 siRNA groups.

KEY FINDINGS

It was shown that MALAT1 mRNA was high expressed in the retinas of OIR mice. Further studies revealed that after intravitreal injection of MALAT1 siRNA, the degree of retinopathy was significantly reduced compared with OIR group. In addition, the protein and mRNA expression levels of CCN1, AKT and VEGF were significantly decreased. This was accompanied by a decrease in inflammatory genes including IL-1β, IL-6, and TNF-α compared with the hyperoxia control siRNA mice.

SIGNIFICANCE

The result suggested that MALAT1 may be involved in the process of RNV in ROP and MALAT1 siRNA may be a promising agent for the treatment of ROP by inhibiting RNV.

Ultra-wide-field scanning laser ophthalmoscopy and optical coherence tomography in FEVR: findings and its diagnostic ability

BACKGROUND/AIMS

To describe some novel vitreoretinal microstructural findings in patients with mild familial exudative vitreoretinopathy (FEVR) on ultra-wide-field scanning laser ophthalmoscopy (UWF-SLO) and UWF optical coherence tomography (UWF-OCT) and to evaluate their clinical significance.

METHODS

A total of 32 patients and 32 healthy controls were studied. An additional independent 40 FEVR patients, 44 patients with non-FEVR retinopathies and 40 healthy controls participated in a diagnostic test to validate the abilities of novel findings in FEVR screening.

RESULTS

A novel anatomic change, named Temporal Mid-Peripheral Vitreoretinal Interface Abnormality (TEMPVIA), was found on UWF-SLO in 88.3% of FEVR patients and in none of the healthy controls. The clinical significance of TEMPVIA was further validated by a diagnostic test in new independent cases, with satisfying sensitivity (91.5%) and specificity (98.8%) and Youden Index 0.90. In addition to foveal hypoplasia, some previously unrecognised, novel clinical changes in FEVR, for instance, retinoschisis, focal retinal thickening, sudden thinning of the retina and retinal ridge, were identified using UWF-OCT.

CONCLUSION

The results of this study have led to an update of the clinical spectrum of FEVR and have improved our understanding of its pathogenesis. TEMPVIA is therefore suggested to be a useful biomarker in the screening strategy for mild FEVR.

Lens-sparing vitrectomy for stage 4A retinopathy of prematurity in infants with aggressive-posterior ROP: Anatomic and functional results

AIM

To assess long-term anatomic and functional outcomes of early lens-sparing vitrectomy (LSV) for stage 4A retinopathy of prematurity (ROP) in infants with aggressive-posterior ROP (AP-ROP) which progressed to retinal detachment despite laser treatment.

METHODS

Chart review of infants who underwent early 25-gage LSV for stage 4A ROP. Outcomes were anatomic success, mean visual acuity (VA), development of postoperative complications, and refractive changes. Follow-up examinations were performed at 1, 3, 6, 12, and then every 6 months.

RESULTS

Ten eyes of seven preterm infants who underwent LSV were included. Mean follow-up was 36 ± 13.4 months and mean postmenstrual age (PMA) at last follow-up was 37 ± 13.7 months. Mean gestational age (GA) and weight at birth was 26 ± 1.4 weeks and 639 ± 180 g. Two eyes had vitreous hemorrhage 4 and 14 days after surgery, respectively. At last follow-up anatomic success was 100%, mean VA was 20/80 and eight eyes (80%) had high myopic refractive correction (mean spherical equivalent -11.25 D).

CONCLUSION

Early LSV for stage 4A ROP with AP-ROP and progression to retinal detachment is efficacious in terms of anatomic and functional outcomes. Anatomic success is associated with visual improvement despite possible myopic refraction changes during follow-up.

Smartphone-Based Fundus Imaging-Where Are We Now?

With the advent of smartphone-based fundus imaging (SBFI), a low-cost alternative to conventional digital fundus photography has become available. SBFI allows for a mobile fundus examination, is applicable both with and without pupil dilation, comes with built-in connectivity and post-processing capabilities, and is relatively easy to master. Furthermore, it is delegable to paramedical staff/technicians and, hence, suitable for telemedicine. Against this background a variety of SBFI applications have become available including screening for diabetic retinopathy, glaucoma, and retinopathy of prematurity and its applications in emergency medicine and pediatrics. In addition, SBFI is convenient for teaching purposes and might serve as a surrogate for direct ophthalmoscopy. First wide-field montage techniques are available and the combination of SBFI with machine learning algorithms for image analyses is promising. In conclusion, SBFI has the potential to make fundus examinations and screenings for patients particularly in low- and middle-income settings more accessible and, therefore, aid tackling the burden of diabetic retinopathy, glaucoma, and retinopathy of prematurity screening. However, image quality for SBFI varies substantially and a reference standard for grading appears prudent. In addition, there is a strong need for comparison of different SBFI approaches in terms of applicability to disease screening and cost-effectiveness.

CircPDE4B inhibits retinal pathological angiogenesis via promoting degradation of HIF-1α though targeting miR-181c

Retinopathy of prematurity is a major cause of childhood blindness worldwide. Hence, exploring the proper treatment methods is a must in tacking this disease. qRT-PCR and western blot were used to detect the expression of genes and proteins, respectively. The proliferation of human retinal vascular endothelial cells (HRECs) was ensured by MTT assay. The luciferase activity was measured through luciferase assay. The inverted phase-contrast light microscope was used to observe the formation of a vascular tube. In the present study, our data demonstrated that circPDE4B was downregulated, while hypoxia-inducible factor-1α (HIF-1α) and VEGFA were upregulated in the retinopathy of prematurity model in vitro and in vivo. CircPDE4B increasing remarkably inhibited the expression of HIF-1α and VEGFA in hypoxia-induced HRECs and subsequent repressed cell proliferation and pathological angiogenesis. We further found that miR-181c suppressed the expression of von Hippel-Lindau (VHL), while circPDE4B could promote VHL expression via binding to miR-181c. Finally, our results revealed that circPDE4B inhibited the expression of VEGFA and pathological angiogenesis via facilitating VHL-mediated ubiquitin degradation of HIF-1α. In conclusion, circPDE4B suppressed the expression of VEGFA and pathological angiogenesis via promoting VHL-mediated ubiquitin degradation of HIF-1α through binding to miR-181c. Our study indicated that circPDE4B might be an effective therapeutic target of retinopathy of prematurity.

Study protocol for prognosis and treatment strategy of peripheral persistent avascular retina after intravitreal anti-VEGF therapy in retinopathy of prematurity

BACKGROUND

Prophylactic peripheral photocoagulation has been proposed to be applied to persistent, peripheral, avascular retina for retinopathy of prematurity (ROP) patients who have received an intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents. However, there are doubts regarding the necessity of this prophylactic action regardless of fundus fluorescein angiography (FFA) results. The adverse prognosis for persistent avascular retina after anti-VEGF therapy in ROP patients is not well understood. The relationship between vascular leakage and an adverse prognosis is also unknown. Therefore, it would be of value to study the above issues to shape the treatment strategy of persistent avascular retina after intravitreal anti-VEGF therapy in ROP patients.

METHODS/DESIGN

This is a prospective study of ROP patients with persistent avascular retina who have received anti-VEGF intravitreal therapy and have never received laser therapy. All the eyes being studied will be followed up and examined by FFA after anti-VEGF treatment and categorized into two groups, a leakage group and a non-leakage group according to the extent of vascular leakage from FFA results. The eyes being studied in the leakage group will be further randomized into two groups, a laser group and a non-laser group. A cohort study (observational) will be conducted on the non-leakage group and the non-laser group (with leakage) to investigate the incidence of an adverse prognosis for reactivation, retinal tear and retinal detachment; as well as to investigate the relationship between vascular leakage from FFA results and the abovementioned pathological changes. A randomized controlled study (experimental) will be conducted on the leakage group to compare the prognosis between the laser group and the non-laser group.

DISCUSSION

The present study aims to investigate the occurrence rates of an adverse prognosis including reactivation, retinal tear and retinal detachment after anti-VEGF therapy in ROP patients with persistent avascular retina; to assess the relationship between vascular leakage from FFA results and the abovementioned pathological changes; to compare the prognosis of persistent avascular retina with or without prophylactic peripheral photocoagulation in these patients; to shape the treatment strategy and provide evidence for the indications of prophylactic photocoagulation.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR), ID: ChiCTR-ROC-17013253. Registered on 5 November 2017. http://www.chictr.org.cn/showproj.aspx?proj=22703.

Effect of red blood cell transfusion on the development of retinopathy of prematurity: A systematic review and meta-analysis

BACKGROUND

The effect of red blood cell (RBC) transfusion on retinopathy of prematurity (ROP) is difficult to establish, because ROP may also be influenced by other factors. Therefore, we carried out a systematic review and meta-analysis to explore the relationship between RBC transfusion and the development of ROP.

METHODS

The PubMed, Embase, Cochrane Library and Web of Science databases were searched from their inception to September 1, 2019. Observational studies that reported the relationship between RBC transfusion and ROP after adjusting for other potential risk factors were included. The combined result was analyzed by a random effect model. Heterogeneity and publication bias were tested, and sensitivity analysis was performed.

RESULTS

Of the 2628 identified records, 18 studies including 15072 preterm infants and 5620 cases of ROP were included. A random effect model was used and revealed that RBC transfusion was significantly associated with ROP (pooled OR = 1.50, 95% CI: 1.27-1.76), with moderate heterogeneity among the included studies (I2 = 44.2%). Subgroup analysis indicated that RBC transfusion was more closely related to ROP in the group with a gestational age (GA) ≤32 weeks (OR = 1.77, 95% CI: 1.29-2.43) but not in the groups with a GA ≤34 weeks (OR = 1.36, 95% CI: 0.85-2.18) or a GA <37 weeks (OR = 1.25, 95% CI: 0.86-1.82). No obvious publication bias was found based on the funnel plot and Egger's test. Removing any single study did not significantly alter the combined result in the sensitivity analysis.

CONCLUSIONS

Our study revealed that RBC transfusion is an independent risk factor for the development of ROP, especially in younger preterm infants. However, there seemed to be no evidence to support an effect of RBC transfusion on ROP in older groups. Further studies addressing this issue in older preterm neonates are warranted.

Inhibition of retinal neovascularization by a PEDF-derived nonapeptide in newborn mice subjected to oxygen-induced ischemic retinopathy

Retinopathy of prematurity (ROP) is a growing cause of lifelong blindness and visual defects as improved neonatal care worldwide increases survival in very-low-birthweight preterm newborns. Advancing ROP is managed by laser surgery or a single intravitreal injection of anti-VEGF, typically at 33-36 weeks gestational age. While newer methods of scanning and telemedicine improve monitoring ROP, the above interventions are more difficult to deliver in developing countries. There is also concern as to laser-induced detachment and adverse developmental effects in newborns of anti-VEGF treatment, spurring a search for alternative means of mitigating ROP. Pigment epithelium-derived factor (PEDF), a potent angiogenesis inhibitor appears late in gestation, is undetected in 25-28 week vitreous, but present at full term. Its absence may contribute to ROP upon transition from high-to-ambient oxygen environment or with intermittent hypoxia. We recently described antiangiogenic PEDF-derived small peptides which inhibit choroidal neovascularization, and suggested that their target may be laminin receptor, 67LR. The latter has been implicated in oxygen-induced ischemic retinopathy (OIR). Here we examined the effect of a nonapeptide, PEDF 336, in a newborn mouse OIR model. Neovascularization was significantly decreased in a dose-responsive manner by single intravitreal (IVT) injections of 1.25-7.5 μg/eye (1.0-6.0 nmol/eye). By contrast, anti-mouse VEGFA₁₆₄ was only effective at 25 ng/eye, with limited dose-response. Combination of anti-VEGFA₁₆₄ with PEDF 336 gave only the poorer anti-VEGF response while abrogating the robust inhibition seen with peptide-alone, suggesting a need for VEGF in sensitizing the endothelium to the peptide. VEGF stimulated 67LR presentation on endothelial cells, which was decreased in the presence of PEDF 336. Mouse and rabbit eyes showed no histopathology or inflammation after IVT peptide injection. Thus, PEDF 336 is a potential ROP therapeutic, but is not expected to be beneficial in combination with anti-VEGF.

Myopia and anterior segment optical coherence tomography findings in laser-treated retinopathy of prematurity eyes

PURPOSE

To evaluate structural features and visual outcomes in eyes with a prior history of laser treatment for retinopathy of prematurity (ROP).

METHODS

Laser-treated eyes for type 1 ROP, preterm monitored eyes, and full-term control eyes were included. LogMAR conversion of Snellen best-corrected visual acuity and spherical equivalent based on cycloplegic refraction were measured in children 5-15 years of age. Anterior segment optical coherence tomography (OCT) was used to study structural features, including anterior chamber angle (ACA) in a subset of eyes.

RESULTS

A total of 50 eyes of 50 patients were included (19 full-term eyes, 19 laser-treated type 1 ROP eyes, 12 preterm monitored eyes). Of these, 44 eyes had visual outcomes data, and 15 eyes had anterior segment data. There was no significant difference in sex or age at final examination between the three groups. There was no significant difference in gestational age between the laser-treated and preterm monitored groups. Compared with the full-term control group and the preterm monitored group, the laser-treated ROP group had narrower ACA and more myopic refractive error. There was a significant correlation between ACA and spherical equivalent.

CONCLUSIONS

Laser treatment may affect angle configuration in ROP eyes. Anterior segment OCT is an easy and useful modality that could aid in screening for visually impairing conditions such as myopia and glaucoma in children with ROP.

A new approach to neonatal medical management that could transform the prevention of retinopathy of prematurity: Theoretical considerations

Retinopathy of prematurity (ROP) is a disease of the immature retina and is the leading global cause of blindness in children. Two postnatal phases of the disease are distinguished, the first phase is thought to be caused by hyperoxia. One of the most relevant ROP risk factor in routine clinical practice is blood transfusion which leads to the introduction into the neonatal circulation of 'non-physiological' adult haemoglobin (HbA) rather than the physiological foetal haemoglobin (HbF). Due to their different affinities for oxygen, HbA will release into retina more oxygen than HbF. It can be expected that this much greater influx of oxygen from HbA may be sensed by the relevant retinal receptors as hyperoxia. Based on the above considerations, I propose that the introduction of non-physiological HbA from adult donors during blood transfusion for anaemia is of key importance in the development and progression of ROP. This hypothesis predicts that there is an HbA limit, beyond which the sequence of events described in the pathogenesis of ROP is triggered. To prevent ROP, I propose launching a new medical field: neonatal transfusion medicine. This system would involve the collection and preparation of umbilical cord blood from the placenta of healthy newborns (containing almost 100% HbF), which would then be administered to premature newborns (who are at risk of ROP) instead of adult blood.

Non-contact smartphone-based fundus imaging compared to conventional fundus imaging: a low-cost alternative for retinopathy of prematurity screening and documentation

Retinopathy of prematurity (ROP) is a frequent cause of treatable childhood blindness. The current dependency of telemedicine-based ROP screening on cost-intensive equipment does not meet the needs in economically disadvantaged regions. Smartphone-based fundus imaging (SBFI) allows for affordable and mobile fundus examination and, therefore, could facilitate cost-effective telemedicine-based ROP screening in low-resources settings. We compared non-contact SBFI and conventional contact fundus imaging (CFI) in terms of feasibility for ROP screening and documentation. Twenty-six eyes were imaged with both SBFI and CFI. Field-of-view was smaller (ratio of diameters, 1:2.5), level of detail was equal, and examination time was longer for SBFI as compared to CFI (109.0 ± 57.8 vs. 75.9 ± 36.3 seconds, p < 0.01). Good agreement with clinical evaluation by indirect funduscopy was achieved for assessment of plus disease and ROP stage for both SBFI (squared Cohen's kappa, 0.88 and 0.81, respectively) and CFI (0.86 and 0.93). Likewise, sensitivity/specificity for detection of plus disease and ROP was high for both SBFI (90%/100% and 88%/93%, respectively) and CFI (80%/100% and 100%/96%). SBFI is a non-contact and low-cost alternative to CFI for ROP screening and documentation that has the potential to considerably improve ROP care in middle- and low-resources settings.

Favorable outcomes in the treatment of aggressive posterior retinopathy of prematurity

OBJECTIVES

To report the results of intravitreal ranibizumab injection as primary therapy in aggressive posterior retinopathy of prematurity, the process of the disease, and the additive treatments performed.

METHODS

This retrospective case review included 15 eyes of 8 premature babies with aggressive posterior retinopathy of prematurity who were initially treated with intravitreal ranibizumab injection. The documented data were gestational age, birth weight, gender, postmenstrual age at intravitreal ranibizumab injection, zone of retinopathy of prematurity, reactivation time of disease, iris neovascularization, retinal hemorrhage, anatomical outcome, and additional treatment.

RESULTS

Median gestational age at birth was 26 (range, 23-27) weeks, birth weight was 730 (range, 550-970) g, and postconceptional age at aggressive posterior retinopathy of prematurity diagnosis and intravitreal ranibizumab injection was 35 (range, 33-35) weeks. Intravitreal ranibizumab injection was performed as primary treatment. Two eyes necessitated a second intravitreal ranibizumab injection. The reactivation of retinopathy of prematurity was 5 (range, 3-7) weeks after intravitreal ranibizumab injection. Recurrence of the disease in Zone II was treated with laser photocoagulation. A favorable outcome was obtained in all eyes (100%).

CONCLUSION

Aggressive posterior retinopathy of prematurity is a serious, rapidly progressing form of retinopathy of prematurity that requires quick and proper management. This study indicates that primary treatment with ranibizumab and laser photocoagulation on recurrence provide favorable anatomical outcomes.

Enhancing Retinal Endothelial Glycolysis by Inhibiting UCP2 Promotes Physiologic Retinal Vascular Development in a Model of Retinopathy of Prematurity

Purpose

We address the hypothesis that uncoupling protein 2 (UCP2), a cellular glucose regulator, delays physiologic retinal vascular development (PRVD) by interfering with glucose uptake through glucose transporter 1 (Glut1).

Methods

In the rat 50/10 oxygen-induced retinopathy (OIR) model, retinal Glut1 and UCP2 were measured and compared to room air (RA)-raised pups at postnatal day 14 (p14). Pups in OIR and RA received intraperitoneal genipin, an UCP2 inhibitor, or control every other day from p3 until p13. Analyses at p14 included avascular/total retinal area (AVA), Western blots of retinal UCP2 and Glut1, and immunostaining of Glut1 in retinal cryosections. Intravitreal neovascular/total retinal area (IVNV) was analyzed at p18, and electroretinograms were performed at p26. Glut1 and phosphorylated VEGFR2 (p-VEGFR2), glucose uptake, adenosine triphosphate (ATP) production, and cell proliferation were measured in human retinal microvascular endothelial cells (hRMVECs) pretreated with genipin or transfected with UCP2siRNA, Glut1siRNA, or control siRNA when incubated with VEGF or PBS.

Results

At p14, OIR pups had increased AVA with decreased Glut1 and increased UCP2 in the retina compared to RA retinas. Intraperitoneal genipin increased retinal Glut1 and reduced AVA. Compared to control, treatment with genipin or knockdown of UCP2 significantly increased Glut1, glucose uptake, ATP production, VEGF-induced p-VEGFR2 and cell proliferation in hRMVECs. Knockdown of Glut1 inhibited VEGF-induced p-VEGFR2. Genipin-treated OIR pups with decreased AVA at p14 had reduced IVNV at p18 and increased amplitudes in a- and b-waves at p26.

Conclusions

Extending PRVD by increasing retinal endothelial glucose uptake may represent a strategy to prevent severe retinopathy of prematurity and vision loss.

Experimental Evidence Behind Clinical Trial Outcomes in Retinopathy of Prematurity

Treatment of severe retinopathy of prematurity (ROP) has evolved over the last decade. This article reviews recent clinical trials and experimental evidence that supports clinical outcomes and observations, including the efficacy of anti-vascular endothelial growth factor (VEGF) agents in reducing the vascular activity of severe ROP, and the mechanisms behind recurrent stage 3 ROP and plus disease in some infants treated with anti-VEGF agents. Also discussed will be current imaging modalities that link experimental models of ROP with longitudinal human studies and which provide exciting future opportunities to enhance the understanding of pathophysiology of ROP and improve treatments. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:228-234.].

Norrie disease gene polymorphism in Indonesian infants with retinopathy of prematurity

OBJECTIVE

Retinopathy of prematurity (ROP) is a major cause of blindness in newborn infants, which also occurs in low-income and middle-income countries. Why ROP progresses in some infants while it regresses in others is still presently unknown. Studies suggest that genetic factors might be involved. Mutations in the Norrie disease (ND) gene are suspected to be related to advanced ROP development. Indonesia is a country with relatively high incidence of ROP, yet the role of these genetic factors in the pathogenesis of ROP cases is still unknown. The study aimed to investigate the presence of mutations in ND on the X chromosome in infants with both non-advanced and advanced ROP in Indonesia.

METHODS AND ANALYSIS

This is a case-control study of polymorphisms in six variants within the ND gene in exon 3, C597A, L108P, R121W, A105T, V60E and C110G, in preterm newborn infants in four major hospitals in Greater Jakarta, Indonesia.

RESULTS

We included 162 preterm newborn infants. ROP was diagnosed in 83 infants, and 79 infants served as controls. Among those with ROP, 57 infants had type 2, while others had type 1. We did not find any gene polymorphisms in any of the infants with ROP nor in the control group.

CONCLUSION

We conclude that it is very unlikely that the six polymorphisms in exon 3 of the ND gene studied in this paper are involved in the development or progression of ROP in preterm infants in our population sample in Indonesia.

Three-dimensional pattern of extraretinal neovascular development in retinopathy of prematurity

BACKGROUND

The application of three-dimensional (3D) visualization techniques to evaluate the earliest visible onset of abnormal retinal vascular development in preterm infants with retinopathy of prematurity (ROP), using bedside non-contact optical coherence tomography (OCT) imaging to characterize morphology and sequential structural changes of abnormal extraretinal neovascularization.

METHODS

Thirty-one preterm infants undergoing routine ROP screening with written informed consent for research imaging were enrolled in this prospective observational study. We imaged the macula and temporal periphery of preterm infants using a handheld OCT system (Envisu 2300 or handheld swept-source research system). The scans obtained were segmented and, using enhanced ray casting, were converted to 3D volumes to which color filter was applied.

RESULTS

Using colorized 3D visualization, we defined extraretinal neovascular structures as buds, bridging networks, and placoid lesions. We could longitudinally follow progression and regression of extraretinal neovascularization in stage 3 ROP after treatment in one infant over 12 weeks and document the appearance of early buds, and formation of florid neovascularization. From stages 2 to 3 ROP, we observed progression from sessile buds to a complex plaque that corresponded to stage 3 ROP on clinical examination. We demonstrated regression of neovascular complexes to small pre-retinal tufts after treatment with anti-VEGF.

CONCLUSIONS

The extension of OCT processing to include surface flattening and colorization that further improved structural analysis rendered better understanding of extraretinal tissue. Our ability to image similar areas in the same infant over multiple visits enabled us to study the evolution of these structural components and follow pathological vascular events longitudinally in development and regression after treatment. These methods can be applied to further study which are likely contribute to our understanding of the pathophysiology of neovascularization in ROP.

Effects of Prematurity on the Cutaneous Microcirculatory Network in the First Weeks of Life

Background: Preterm infants are at increased risk for hypertension in adolescence. Microcirculatory dysfunction has been identified as an underlying cause for cardiovascular disease. Our goal was to document the development of the cutaneous microcirculation in preterm infants during the first weeks of life and to compare it to the situation in term infants at birth. Methods: In 20 preterm infants, microcirculatory parameters were obtained prospectively by Sidestream Dark Field (SDF) Imaging at the upper inner arm once a week until discharge or 37 weeks of gestational age. A single microcirculatory measurement was obtained in 30 term infants during the first 3 days of life. Videos were blinded and analyzed with the AVA software. Results: Microcirculatory parameters in preterm infants differ significantly from term infants with a lower vessel surface (VS), a lower percentage of large and medium but higher percentage of small vessels, a higher Functional Vessel Density (FVD), and a higher Microcirculatory Flow Index (MFI). In multivariable linear regression models we could demonstrate a statistically significant association between the dependent microcirculatory variables (VS, diameter distribution, MFI) and gestational age as independent predictor variable while adjusting for postnatal days of life. Looking at the longitudinal follow-up data of preterm infants by means of a multivariable mixed-effects linear regression model adjusting for clinical variables, there is a significant decrease in FVD with increasing postnatal age, however no other significant changes in microcirculatory parameters over time. Accordingly, comparing the microcirculatory parameters of near term former preterm infants with term born neonates, we could still find significant differences with a higher FVD, lower VS and differences in vessel diameters in the former premature group. Conclusion: Infants born prematurely exhibit distinct microcirculatory alterations compared to term neonates with gestational age at birth being associated with microvascular parameters. Interestingly, this premature vascular phenotype persists even close to corrected term age. In view of the known increased cardiovascular risk of former preterm infants, our observations might have important clinical impact. The factors governing the development of the microvascular network in preterm infants and the contribution of microcirculatory changes observed here to vascular pathology in later life need to be further investigated.

Effects of LY294002 on the function of retinal endothelial cell in vitro

AIM

To study the effects of LY294002 [phosphatidylinositol 3-kinase (PI3K) inhibitor] on the function and mechanisms of retinal endothelial cells (RECs) in vitro.

METHODS

RECs were randomly divided into control group and LY294002 treatment group. RECs in the control group were placed the incubator for hypoxic exposure in vitro. RECs in the LY294002 treatment group were pretreated with LY294002 (40 µmol/L) under hypoxic condition. The expression of matrix metalloproteinase (MMP)-2, MMP-9, vascular endothelial growth factor (VEGF), and apoptosis and proliferation of RECs were evaluated with Western blot, real-time reverse transcription-polymerase chain reaction (RT-PCR), and flow cytometric analysis, correspondently.

RESULTS

Compared with the control group, treating the RECs with LY294002 was able to remarkably inhibit cell proliferation rates (t_1d=2.13, t_2d=2.65, t_3d=2.36, t_4d=2.06, all P<0.05). Flow cytometric analysis indicated that a moderate increase in apoptosis in the LY294002 treatment group compared to the control group (t=2.51, P<0.05). The expression of MMP-2, MMP-9 and VEGF were downregulated in the LY294002 treatment group by Western blot and real-time RT-PCR (all P<0.05).

CONCLUSION

LY294002 regulates the function of RECs by reducing the expression of MMP-2, MMP-9, and VEGF in vitro. LY294002 may provide an effective method for preventing pathological angiogenesis.

Blockade of TREM-1 prevents vitreoretinal neovascularization in mice with oxygen-induced retinopathy

In pathological retinal neovascularization (RNV) disorders, the retina is infiltrated by activated leukocytes and macrophages. Triggering receptor expressed on myeloid cells 1 (TREM-1), an inflammation amplifier, activates monocytes and macrophages and plays an important role in cancer, autoimmune and other inflammation-associated disorders. Hypoxia-inducible TREM-1 is involved in cancer angiogenesis but its role in RNV remains unclear. Here, to close this gap, we evaluated the role of TREM-1 in RNV using a mouse model of oxygen-induced retinopathy (OIR). We found that hypoxia induced overexpression of TREM-1 in the OIR retinas compared to that of the room air group. TREM-1 was observed specifically in areas of pathological RNV, largely colocalizing with macrophage colony-stimulating factor (M-CSF) and CD45- and Iba-1-positive cells. TREM-1 blockade using systemically administered first-in-class ligand-independent TREM-1 inhibitory peptides rationally designed using the signaling chain homooligomerization (SCHOOL) strategy significantly (up to 95%) reduced vitreoretinal neovascularization. The peptides were well-tolerated when formulated into lipopeptide complexes for peptide half-life extension and targeted delivery. TREM-1 inhibition substantially downregulated retinal protein levels of TREM-1 and M-CSF suggesting that TREM-1-dependent suppression of pathological angiogenesis involves M-CSF. Targeting TREM-1 using TREM-1-specific SCHOOL peptide inhibitors represents a novel strategy to treat retinal diseases that are accompanied by neovascularization including retinopathy of prematurity.

Macular Structures, Optical Components, and Visual Acuity in Preschool Children after Intravitreal Bevacizumab or Laser Treatment

PURPOSE

To investigate the macular structures, optical components, and visual acuity in preschool-aged children with a history of type I retinopathy of prematurity who underwent either intravitreal bevacizumab (IVB), laser, or a combination of treatments.

DESIGN

Comparative interventional case series.

METHODS

Setting: A referred medical center in Taiwan.

STUDY POPULATION

Eighty eyes from 42 patients (33 IVB-treated eyes from 17 children, 24 laser-treated eyes from 13 children, and 23 laser + IVB-treated eyes from 12 children).

OBSERVATION PROCEDURE

Spectral-domain optical coherence tomography.

MAIN OUTCOME MEASURES

The retinal thickness in the foveal area and the associated morphologic changes in foveal depression.

RESULTS

Compared with the laser-treated and laser + IVB-treated eyes, the IVB-treated eyes had less myopia and deeper anterior chamber depths but presented similar axial lengths and corneal curvatures (P = .001, P = .002, P = .95, and P = .16, respectively). The IVB-treated eyes had significantly thinner foveal, parafoveal, and perifoveal retinal thicknesses (P < .01 for all) and a higher incidence of foveal depression than the laser- or laser + IVB-treated eyes. The macular and subfoveal choroidal thicknesses did not differ among the groups (P = .21 and P = .63, respectively). Moreover, compared with the eyes treated with laser or laser + IVB, the IVB-treated eyes had better uncorrected visual acuity, although a significant difference was not observed in best-corrected visual acuity (P = .008 and P = .29, respectively).

CONCLUSIONS

Compared with laser therapy, IVB-treated eyes were associated with deeper anterior chamber depths and thinner foveal, parafoveal, and perifoveal thicknesses. Moreover, these IVB-treated eyes had fewer refractive errors and better uncorrected visual acuity.

The Erythropoietin Promoter Variant rs1617640 Is Not Associated with Severe Retinopathy of Prematurity, Independent of Treatment with Erythropoietin

In this case-control study, the erythropoietin (EPO) promoter variant s1617640, linked to high intravitreal EPO concentrations and increased risk of diabetic retinopathy, was not associated with severe retinopathy of prematurity. This finding was observed both in infants with and without recombinant EPO administration.

Outcomes and prognostic factors for aggressive posterior retinopathy of prematurity following initial treatment with intravitreal ranibizumab

Background

This study sought to identify factors associated with retinal detachment and retreatment of aggressive posterior retinopathy of prematurity (APROP) initially treated with intravitreal ranibizumab (IVR) injection as well as the efficacy of IVR treatment.

Methods

This was a retrospective study. A total of 83 preterm infants (160 eyes) diagnosed with APROP who were primarily treated with IVR were included. The 160 eyes were divided into two groups based on the anatomic outcomes. Group A included 35 eyes that developed retinal detachment, and Group B included 125 eyes without retinal detachment. The following patient factors were retrospectively reviewed: gender, gestational age (GA), birth weight (BW), postmenstrual age (PMA) at first treatment, iris neovascularizations, retinal hemorrhage, neutrophil and lymphocyte counts before the first intravitreal injection, neutrophil-to-lymphocyte ratio (NLR), anatomical outcomes, additional treatment and follow-up time. Three dummy variables were created as dependent variables based on the methods of retreatment. The possible risk factors for APROP were evaluated, and statistical analyses included univariate and multivariate logistic regression.

Results

A total of 160 eyes from 83 preterm infants (56 males and 27 females) underwent initial IVR treatment with a follow-up time of 17.17 ± 10.54 months. Thirty-five of the 160 (21.9%) eyes progressed to retinal detachment, and 82 of the 125 (65.6%) non-retinal detachment eyes needed retreatment, with favorable anatomical outcomes. The disease improved approximately 1.5 ± 1.2 weeks after the first IVR treatment. The mean recurrence period of APROP was approximately 7.5 ± 6.9 weeks after the first IVR treatment. Multiple logistic regression analysis revealed postmenstrual age (P < 0.001) and neutrophil count (P = 0.009) as the most significant factors for retinal detachment in APROP. Retinal hemorrhage (P = 0.007) and BW (P = 0.04) were most significantly associated with APROP recurrence and retreatment.

Conclusions

IVR injection is an effective treatment for APROP. In this study, older postmenstrual age and low neutrophil count were identified as risk factors for retinal detachment in APROP. In addition, retinal hemorrhage and low BW were significantly associated with recurrence and retreatment in non-retinal detachment APROP. Thus, patients with a lower BW, older postmenstrual age, low neutrophil count and retinal hemorrhage should be reexamined in a timely and more frequent manner.

The utility of ultra-widefield fluorescein angiography in pediatric retinal diseases

Background

Ultra-widefield angiography is the latest technology in the evolution of fundus fluorescein angiography. With the ability to capture up to 200° of the fundus in a single image, far peripheral retinal pathology can be imaged. Generally, obtaining high-quality fundus fluorescein angiography in a child without sedation in the outpatient setting is exceedingly challenging. Therefore, there are advantages to imaging platforms that can capture the peripheral retina in young children without anesthesia. Often pediatric retinal diseases have pathology localized to the far periphery, which further validates the utility of ultra-widefield angiography. Ultra-widefield angiography has been successfully used without sedation for evaluation of children with various pediatric retinal diseases such as Coats disease, familial exudative vitreoretinopathy, and retinopathy of prematurity.

Conclusion

This non-contact, non-mydriatic modality has been utilized in the evaluation of pediatric retinal diseases and demonstrated to have benefits over conventional fluorescein angiography techniques.

Pharmacotherapy and ROP: Going Back to the Basics

Retinopathy of prematurity (ROP) is a leading cause of blindness in preterm infants around the world. Through the development of animal models and clinical trials our understanding of the pathophysiology of this disease and approach to therapy has evolved significantly since ROP was first described in the 1940s in the United States. The mainstay of treatment in ROP remains ablative laser therapy to the avascular retina but pharmacologic agents are being more and more commonly used with new targets for pharmacotherapy emerging. This paper summarizes our current understanding of the pathophysiology of ROP based on the data gleaned from animal models and discusses current approaches to pharmacotherapy.

Medical and developmental outcomes of bevacizumab versus laser for retinopathy of prematurity

BACKGROUND

Infants with stage 3+ retinopathy of prematurity (ROP) in zone I or zone II posterior were randomized to initial treatment with bevacizumab or laser in a multicenter trial (BEAT-ROP). The purpose of this study was to assess the effects of bevacizumab on nonophthalmologic outcomes.

METHODS

At one study site, inborn infants of <27 weeks' gestational age underwent medical and standardized neurologic and developmental assessments at 18-22 months' corrected age (age after expected date of full-term delivery).

RESULTS

Of the 18 infants enrolled at our site, 16 (7 bevacizumab, 9 laser) were evaluated for medical and neurodevelopmental outcomes at 18-28 months' corrected age. For each of the groups, the medians and ranges of growth percentiles were low compared with norms for healthy infants. The ranges for Bayley III developmental scores were also low relative to expected norms for healthy infants. There were no significant differences between the bevacizumab and laser therapy groups in weight (median percentile: bevacizumab, 18; laser, 7), length, head circumference, cerebral palsy, or Bayley scores (median Cognitive Composite Score: bevacizumab, 85; laser, 65). There was a significant difference in length of hospital stay (median days, 98 vs 140 days) favoring the bevacizumab group.

CONCLUSIONS

In this patient cohort 2-year follow-up evaluation of infants treated with bevacizumab versus laser therapy for retinopathy of prematurity showed no adverse effects on medical or neurodevelopmental outcomes.

Targeted Knockdown of Overexpressed VEGFA or VEGF164 in Müller cells maintains retinal function by triggering different signaling mechanisms

Oxygen-induced retinopathy (OIR) upregulates Müller cell vascular endothelial growth factor A (VEGFA) that causes intravitreal neovascularization similar to severe retinopathy of prematurity (ROP). Safety concerns exist with anti-VEGF treatment for ROP. We evaluated long-term knockdown of Müller cell-VEGFA with short-hairpin RNAs to VEGFA or VEGF164 via subretinal lentivirus delivery (L-VEGFAshRNA, L-VEGF164shRNA) on retinal structure and function in a rat OIR model. Lectin-stained retinal flat mounts analyzed for areas of avascular/total retina (AVA) and intravitreal neovascular/total retina (IVNV) showed initial significantly reduced IVNV by L-VEGFAshRNA and L-VEGF164shRNA compared to control, luciferase-shRNA lentivirus, without late recurrence. Spectral-domain optical coherence tomography (OCT) and immunohistochemical sections (IHC) demonstrated changes in retinal layer thicknesses in L-VEGFAshRNA or L-VEGF164shRNA  compared to control. Ganzfeld electroretinograms were increased in L-VEGFAshRNA or L-VEGF164shRNA compared to control. Erythropoietin (EPO), brain-derived neurotrophic factor, glial-derived neurotrophic factor, nerve growth factor, neurotrophin-3 (NT-3) mRNAs were increased in L-VEGFAshRNA, but not L-VEGF164shRNA retinas. In cultured rat Müller cells, knockdown of VEGF upregulated NT-3 and EPO, whereas treatment with EPO activated neuroprotective signaling. Methods to reduce IVNV by selective knockdown of VEGFA, and particularly VEGF164, in Müller cells may have fewer deleterious effects than nonselective VEGFA inhibition to all cells in the retina.

Analysis of Retinal Vascular Plexuses and Interplexus Connections

The retina is a highly organized neural tissue consisting of three neural layers and two synaptic layers. Blood vessels that nourish the mouse and human neural retina mirror this organization consisting of three plexus layers, or plexuses, that run parallel within the retina, connected by interplexus vessels to create a closed vascular network. Here, we describe a methodology to describe this organization that can be used to interrogate factors mediating retinal vessel patterning including: coverage of the vascular plexuses, branching and orientation of the interplexus connections, and digital reconstruction of the retinal vasculature to measure vessel length and density. The methodology focuses on the mouse retina, but can easily be adapted to study retinal vessels of other species.

Targeting Intramembrane Protein-Protein Interactions: Novel Therapeutic Strategy of Millions Years Old

Intramembrane protein-protein interactions (PPIs) are involved in transmembrane signal transduction mediated by cell surface receptors and play an important role in health and disease. Recently, receptor-specific modulatory peptides rationally designed using a general platform of transmembrane signaling, the signaling chain homooligomerization (SCHOOL) model, have been proposed to therapeutically target these interactions in a variety of serious diseases with unmet needs including cancer, sepsis, arthritis, retinopathy, and thrombosis. These peptide drug candidates use ligand-independent mechanisms of action (SCHOOL mechanisms) and demonstrate potent efficacy in vitro and in vivo. Recent studies surprisingly revealed that in order to modify and/or escape the host immune response, human viruses use similar mechanisms and modulate cell surface receptors by targeting intramembrane PPIs in a ligand-independent manner. Here, I review these intriguing mechanistic similarities and discuss how the viral strategies optimized over a billion years of the coevolution of viruses and their hosts can help to revolutionize drug discovery science and develop new, disruptive therapies. Examples are given.