Pregnancy-induced hypertension and retinopathy of prematurity: a meta-analysis

Retinopathy of prematurity protection conferred by uteroplacental insufficiency through erythropoietin signaling in an experimental Murine Model

BACKGROUND

Recent clinical studies suggest that preeclampsia, characterized by uteroplacental insufficiency (UPI) and infant intrauterine growth restriction (IUGR), may be protective against retinopathy of prematurity (ROP) in preterm infants. Experimental models of UPI/IUGR have found an association of erythropoietin (EPO) with less severe oxygen-induced retinopathy (OIR); however, it is unclear if EPO/EPO receptor (EPOR) signaling was involved. We hypothesized that maternal UPI and resultant infant IUGR would protect against features of ROP through EPO/EPOR signaling.

METHODS

We compared transgenic mice with hypoactive EPOR signaling (hWtEPOR) to littermate wild-type mice (mWtEpoR) in a novel combined model of IUGR and ROP. Thromboxane A2 (TXA2) was infused into pregnant C57Bl/6J dams to produce UPI/IUGR; postnatal pups and their foster dams were subjected to a murine OIR model.

RESULTS

Following hyperoxia, hematocrits were similar between littermate wild-type (mWtEpoR) TXA2/OIR and vehicle/OIR pups. mWtEpoR TXA2/OIR had increased serum EPO, retinal EPO and VEGF, and decreased avascular retinal area (AVA) compared to vehicle/OIR pups. In comparison to the mWtEpoR TXA2/OIR pups, AVA was not reduced in hWtEPOR TXA2/OIR pups.

CONCLUSION

Our findings provide biologic evidence that UPI/OIR-induced endogenous EPOR signaling confers protection against hyperoxia-induced vascular damage that may be related to pathophysiology in ROP.

IMPACT

Maternal preeclampsia and infant growth restriction confer retinovascular protection against high oxygen-induced damage through endogenous erythropoietin signaling.

Systemic Cytokines in Retinopathy of Prematurity

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

PRENATAL MATERNAL CHARACTERISTICS ASSOCIATED WITH RETINOPATHY OF PREMATURITY

PURPOSE

Determine whether prenatal maternal characteristics such as sociodemographic characteristics, comorbidities, or pregnancy complications affect retinopathy of prematurity (ROP) development.

METHODS

Medical records of 236 mother-infant dyads from our institution were reviewed, only including dyads in which infants were born at 30 weeks gestational age or earlier. The primary outcome measure was the risk of ROP (defined Stage 1 or greater in either eye) and its association with prenatal maternal variables.

RESULTS

Maternal Medicaid insurance, smoking during pregnancy, and chorioamnionitis were associated with an increased risk of ROP. For Medicaid insurance and chorioamnionitis, these risks were not appreciably altered by adjustment for potential confounders.

CONCLUSION

These results suggest that several prenatal maternal factors may independently affect the risk of ROP in preterm infants. Validation of our findings could aid in the identification of infants at high risk for ROP based on prenatal clinical features.

Effect of ranibizumab on retinopathy of prematurity: A meta-analysis

The primary objective of this study was to systematically evaluate the clinical efficacy of intravitreal ranibizumab injection in the treatment for retinopathy of prematurity (ROP) in infants. The MEDLINE (PubMed), Embase, China Biology Medicine disc, Cochrane Library, Web of Science, WanFang Data, CNKI, and CQVIP databases were searched to collect randomized controlled trials (RCTs) comparing the efficacy of ranibizumab with laser treatment in ROP. The retrieval time was from 2007, on which ranibizumab was approved until 12 January 2022. Data were extracted based on predetermined inclusion and exclusion criteria. Two investigators employed QUADAS-2 to independently assess the quality of all eligible original studies. Following quality evaluation, we also performed a meta-analysis using STATA v 15.1 and RevMan v 5.4 and funnel plots were used to detect publication bias. A total of five RCTs were included in the meta-analysis. In this study, the regression rate of retinal neovascularization was used as the index of therapeutic effectiveness. According to the results, the retinal neovascularization regression rate of the intravitreal ranibizumab injection group was statistically higher than that of the laser therapy group [risk ratio (RR) = 1.26, 95% confidence interval (CI): 1.18–1.35]; however, the incidence of adverse events, including recurrence and complications, was not different between them (RR = 0.73, 95%CI: 0.19–2.80). Therefore, intravitreal ranibizumab injection may be more clinically effective than laser therapy in the treatment for ROP. The safety and efficacy of ranibizumab in the long-term treatment for ROP needs further investigation.

Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, CRD42022296387