The role of serum apelin in retinopathy of prematurity

Differences in Oxygen-Induced Retinopathy Susceptibility Between Two Sprague Dawley Rat Vendors: A Comparison of Retinal Transcriptomes

PURPOSE

To determine the retinal transcriptomic differences underlying the oxygen-induced retinopathy phenotypes between Sprague Dawley rat pups from two commonly used commercial vendors. This will allow us to discover genes and pathways that may be related to differences in disease severity in similarly aged premature babies and suggest possible new treatment approaches.

METHODS

We analyzed retinal vascular morphometry and transcriptomes from Sprague Dawley rat pups from Charles River Laboratories and Envigo (previously Harlan). Room air control and oxygen-induced retinopathy groups were compared. Oxygen-induced retinopathy was induced with the rat 50/10 model.

RESULTS

Pups from Charles River Laboratories developed a more severe oxygen-induced retinopathy phenotype, with 3.6-fold larger percent avascular area at P15 and twofold larger % neovascular area at P20 than pups from Envigo. Changes in retinal transcriptomes of rat pups from both vendors were substantial at baseline and in response to oxygen-induced retinopathy. Baseline differences centered on activated pathways of neuronal development in Charles River Laboratories pups. In response to oxygen-induced retinopathy, during the neovascular phase, retinas from Charles River Laboratories pups exhibited activation of pathways regulating necrosis, neuroinflammation, and interferon signaling, supporting the observed increase of neovascularization. Conversely, retinas from Envigo pups showed decreased necrosis and increased focal adhesion kinase signaling, supporting more normal vascular development. Comparing oxygen-induced retinopathy transcriptomes at P15 to those at P20, canonical pathways such as phosphate and tensin homolog, interferon, and coordinated lysosomal expression and regulation element signaling were identified, highlighting potential novel mechanistic targets for future research.

CONCLUSION

Transcriptomic profiles differ substantially between rat pup retinas from Charles River Laboratories and Envigo at baseline and in response to oxygen-induced retinopathy, providing insight into vascular morphologic differences. Comparing transcriptomes identified new pathways for further research in oxygen-induced retinopathy pathogenesis and increased scientific rigor of this model.

Plasma Level of Apelin as a Promising Factor for Retinopathy of Prematurity

INTRODUCTION

The aim of this study was to investigate the relevance of plasma levels of apelin and other risk factors in infants with retinopathy of prematurity (ROP).

METHODS

This was a single-center cross-sectional study. Fifty preterm infants with ROP and 50 preterm infants without ROP were enrolled. The analysis included evaluation of gestational age (GA), birth weight (BW), and measurement of plasma concentrations of apelin, vascular endothelial growth factor (VEGF), erythropoietin (EPO), and insulin-like growth factor (IGF-1) using enzyme-linked immunosorbent assay.

RESULTS

The mean BW and GA of babies with ROP were considerably lower than those without ROP (p < 0.001, p = 0.003, respectively). Plasma levels of VEGF, EPO, and IGF-1 were all lower in babies with ROP (all p < 0.001), while plasma apelin levels were greater (p < 0.001). We compared the sensitivity and selected the best cut-offs while keeping the specificity constant (80.0%). Among all the criteria, plasma apelin levels had the best sensitivity (72%), with the cut-off of 21.08 pg/mL. Multivariable logistic regression analyses showed that the plasma level of apelin was the only parameter associated with ROP (p = 0.02, OR = 16, 95% CI: 1.54-166.53). The area under the curve of the multivariable regression model that comprised GA, BW alone was 0.67, while that of the model that included apelin was 0.90.

CONCLUSIONS

Plasma apelin level demonstrated good sensitivity and specificity with regard to the association of ROP; the inclusion of apelin may be a promising factor to include in screening criteria.

Correlation between apelin and VEGF levels in retinopathy of prematurity: a matched case-control study

Background

Although several clinical studies have analysed the relationship between the levels of vascular endothelial growth factor (VEGF) and apelin-13 in venous blood and retinopathy of prematurity (ROP), no definitive conclusions have been reached. This study aimed to investigate the relationship between apelin-13 levels and VEGF levels and ROP.

Methods

Differences in plasma apelin-13 and VEGF levels were analysed in two groups of infants born with birth weight < 1500 g and gestational age < 32 weeks at Peking University People’ s Hospital. One group comprised infants diagnosed with ROP and the other group was a control group comprising infants without ROP.

Results

Apelin-13 levels were significantly lower in the ROP group than in the control group, while VEGF levels showed the opposite result (both P < 0.001). Infants with severe ROP had lower apelin-13 levels and higher VEGF levels than with mild ROP (both P < 0.05).The receiver operating characteristic curve for apelin-13 level as the indicator of ROP showed that a cut-off value of 119.6 pg/mL yielded a sensitivity of 84.8% and a specificity of 63.6%, while for VEGF level, the cut-off value of 84.3 pg/mL exhibited a sensitivity of 84.8% and a specificity of 66.7%.

Conclusions

Plasma apelin-13 and VEGF levels at 4–6 weeks of age may play a role in assisting the diagnosis of ROP.

Multiple roles of apelin/APJ system in eye diseases

Apelin is an endogenous ligand of G protein-coupled receptor (APJ), and they compose apelin/APJ system. Apelin/APJ system is widely distributed in tissues and plays pleiotropic roles. Attractively, more emphasis has recently been placed on the effects of apelin/APJ system in eye diseases, such as retinopathy of prematurity (ROP), diabetic retinopathy (DR) and diabetic macular edema (DME). In this review, we elaborated the roles of apelin/APJ system in the pathophysiological processes of eye. Concretely, apelin/APJ system induces retinal gliosis and angiogenesis. Hypoxia-inducible factors (HIFs) are involved in apelin/APJ system-triggered ROP progress. Apelin/APJ system mediates DR-induced retinopathy. Apelin/APJ system maintains retinal functions and health by protecting Müller cells from apoptosis. Apelin/APJ system suppresses the NMDA-induced retinal ganglion cell (RGC) loss to protect optic nerve damage. Overall, apelin/APJ system is a potential therapeutic target for eye disease.

Incidence and Risk Factors for Retinopathy of Prematurity (ROP) in Biggest Neonatal Intensive Care Unit in Itay Elbaroud City, Behera Province, Egypt

Aim of the Work

To evaluate the incidence and risk factors for development of retinopathy of prematurity (ROP) in the biggest neonatal intensive care unit (NICU) in Itay Elbaroud City, Behera province, Egypt.

Methods

We studied data of 240 newly born infants with gestational age (GA) ≤34 weeks or birth weight (BW) ≤2000 g or infants with unstable course who were admitted to the biggest NICU in Itay Elbaroud City, Behera province, Egypt, 
between October 1, 2018 and October 31, 2020. There is no standard screening system in Egypt. Furthermore, we had screened babies more than 1500 g, more than 32 weeks and found signs of ROP, so we decided to expand our inclusion criteria to include babies up to 2000 g of birth weight and up to 34 weeks gestational age in addition to older and heavier babies with unstable course in NICUs. Clinical information about perinatal neonates was collected by reviewing medical charts. The main outcomes are the incidence and severity of ROP. The relationship of clinical risk factors and the development of ROP were analyzed.

Results

The overall incidence of ROP was 34.1%, and the overall incidence of type 1 ROP was 26.3% of infants. ROP was significantly associated with GA (odds ratio; OR: 6.8; (3.7–12.3), BW (OR: 4.1; 2.3–7.3), apnea, supplementary oxygen administration, and thrombocytopenia.

Conclusion

The incidence of ROP is high in Itay Elbaroud city, Behera Province, Egypt. Immaturity, low birth weight, low gestational age, oxygen administration, apnea, thrombocytopenia, and jaundice are important risk factors for development of ROP.

Retinopathy prematurity: a systematic review and meta-analysis study based on neonatal and maternal risk factors

BACKGROUND

Retinopathy of prematurity is the abnormal development of retinal arteries in preterm neonates less than 32 weeks and weighing 1500 g, and less, which can lead to visual impairment during life and blindness. This study aims to investigate the relationship between some clinical characteristics of neonates and mothers with Retinopathy of prematurity in the world via a systematic review and meta-analysis.

MATERIALS AND METHODS

The present study is a systematic review and meta-analysis on the relationship between maternal and neonatal clinical variables with Retinopathy of prematurity in the world from the beginning of 2000 to the end of 2020. Accordingly, all English articles published on the topic were searched in scientific databases of Web of Science, PubMed, Google Scholar, Science Direct, and Scopus. The articles were searched independently by two researchers. Statistical analysis of data was performed using fixed and random effects model statistical tests in the meta-analysis, Cochran, meta-regression, I² index, Funnel plot, and Begg's by STATA software program, version 14.

RESULT

A total of 191 studies with a sample size of 140,921 persons were including in the meta-analysis. Accordingly, Preterm delivery ≤28 weeks (OR:6.3, 95% CI:4.9-8.1), Birth Weight ≤1000 g (OR:5.8, 95% CI:4.8-6.8), Birth Weight ≤1500 g (OR:4.8, 95% CI:3.8-6.1), PROM (OR:1.2, 95% CI:1.0-1.4), induced fertility (OR:1.9, 95% CI:1.1-3.0) and Chorioamnionitis (OR:1.5, 95% CI:1.0-2.2) There was a statistically significant association with retinopathy.

CONCLUSION

Based on the results of the present meta-analysis, the risk of retinopathy of prematurity in neonates born at 28 weeks and less, LBW (weight 1500 g and less), neonatal hypotension, chorioamnionitis, and induced fertility increases.

Monitoring of tumor vascular normalization: the key points from basic research to clinical application

Tumor vascular normalization alleviates hypoxia in the tumor microenvironment, reduces the degree of malignancy, and increases the efficacy of traditional therapy. However, the time window for vascular normalization is narrow; therefore, how to determine the initial and final points of the time window accurately is a key factor in combination therapy. At present, the gold standard for detecting the normalization of tumor blood vessels is histological staining, including tumor perfusion, microvessel density (MVD), vascular morphology, and permeability. However, this detection method is almost unrepeatable in the same individual and does not dynamically monitor the trend of the time window; therefore, finding a relatively simple and specific monitoring index has important clinical significance. Imaging has long been used to assess changes in tumor blood vessels and tumor changes caused by the oxygen environment in clinical practice; some preclinical and clinical research studies demonstrate the feasibility to assess vascular changes, and some new methods were in preclinical research. In this review, we update the most recent insights of evaluating tumor vascular normalization.

Retinopathy of prematurity: a review of risk factors and their clinical significance

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease that affects premature infants. Despite improvements in neonatal care and management guidelines, ROP remains a leading cause of childhood blindness worldwide. Current screening guidelines are primarily based on two risk factors: birth weight and gestational age; however, many investigators have suggested other risk factors, including maternal factors, prenatal and perinatal factors, demographics, medical interventions, comorbidities of prematurity, nutrition, and genetic factors. We review the existing literature addressing various possible ROP risk factors. Although there have been contradictory reports, and the risk may vary between different populations, understanding ROP risk factors is essential to develop predictive models, to gain insights into pathophysiology of retinal vascular diseases and diseases of prematurity, and to determine future directions in management of and research in ROP.