Effects of apelin on retinal microglial cells in a rat model of oxygen-induced retinopathy of prematurity

Identification of novel biomarkers for retinopathy of prematurity in preterm infants by use of innovative technologies and artificial intelligence

Retinopathy of prematurity (ROP) is a leading cause of preventable vision loss in preterm infants. While appropriate screening is crucial for early identification and treatment of ROP, current screening guidelines remain limited by inter-examiner variability in screening modalities, absence of local protocol for ROP screening in some settings, a paucity of resources and an increased survival of younger and smaller infants. This review summarizes the advancements and challenges of current innovative technologies, artificial intelligence (AI), and predictive biomarkers for the diagnosis and management of ROP. We provide a contemporary overview of AI-based models for detection of ROP, its severity, progression, and response to treatment. To address the transition from experimental settings to real-world clinical practice, challenges to the clinical implementation of AI for ROP are reviewed and potential solutions are proposed. The use of optical coherence tomography (OCT) and OCT angiography (OCTA) technology is also explored, providing evaluation of subclinical ROP characteristics that are often imperceptible on fundus examination. Furthermore, we explore several potential biomarkers to reduce the need for invasive procedures, to enhance diagnostic accuracy and treatment efficacy. Finally, we emphasize the need of a symbiotic integration of biologic and imaging biomarkers and AI in ROP screening, where the robustness of biomarkers in early disease detection is complemented by the predictive precision of AI algorithms.

Immunomodulation of MiRNA-223-based nanoplatform for targeted therapy in retinopathy of prematurity

Retinopathy of prematurity (ROP) is characterized by pathological angiogenesis and associated inflammation in the retina and is the leading cause of childhood blindness. MiRNA-223 (miR-223) drives microglial polarization toward the anti-inflammatory phenotype and offers a therapeutic approach to suppress inflammation and consequently pathological neovascularization. However, miRNA-based therapy is hindered by the low stability and non-specific cell-targeting ability of delivery systems. In the present study, we developed folic acid-chitosan (FA-CS)-modified mesoporous silica nanoparticles (PMSN) loaded with miR-223 to regulate retinal microglial polarization. The FA-CS/PMSN/miR-223 nanoparticles exhibited high stability and loading efficiency, achieved targeted delivery, and successfully escaped from lysosomes. In cultured microglial cells, treatment with FA-CS/PMSN/miR-223 nanoparticles upregulated the anti-inflammatory gene YM1/2 and IL-4RA, and downregulated the proinflammatory genes iNOS, IL-1β, and IL-6. Notably, in a mouse oxygen-induced retinopathy model of ROP, intravitreally injected FA-CS/PMSN/miR-223 nanoparticles (1 μg) decreased the retinal neovascular area by 52.6%. This protective effect was associated with the reduced and increased levels of pro-inflammatory (M1) and anti-inflammatory (M2) cytokines, respectively. Collectively, these findings demonstrate that FA-CS/PMSN/miR-223 nanoparticles provide an effective therapeutic strategy for the treatment of ROP by modulating the miR-223-mediated microglial polarization to the M2 phenotype.

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.

G-protein coupled estrogen receptor activation protects the viability of hyperoxia-treated primary murine retinal microglia by reducing ER stress

In this study, we investigated the effects of G-protein coupled estrogen receptor (GPER) activation in the early phase of retinopathy of prematurity (ROP) and its association with endoplasmic reticulum (ER) stress using primary murine retinal microglia as an experimental model. Fluorescence microscopy results show that the CD11c-positive primary retinal microglia in vitro cultured for 14 days were GPER-positive. GPER activation using GPER-agonist G-1 reduced autophagy and increased the viability of the hyperoxia-treated primary murine retinal microglia. Furthermore, GPER activation reduced the expression of ER stress-related proteins, IRE1α, PERK and ATF6 in the hyperoxia-treated primary murine retinal microglia compared to the corresponding controls. GPER activation significantly reduced a time-dependent increase in IP3R-dependent calcium release from the ER, thereby maintaining higher calcium levels in the ER of hyperoxia-treated primary retinal microglia. However, the protective effects of G-1 on the hyperoxia-treated primary retinal microglia were eliminated by inactivation of GPER using the GPER-antagonist, G-15. In conclusion, our study demonstrates that GPER activation enhances the survival of hyperoxia-treated primary retinal microglia by reducing ER stress. Our study demonstrates the therapeutic potential of GPER agonists such as G-1 in the early phase of ROP.