Chronic Placental Inflammation as a Risk Factor of Severe Retinopathy of Prematurity

Comprehensive assessment of placental inflammation: Novel approach in predicting retinopathy of prematurity

The purpose of this study was to determine the independent association between placental inflammation and the development of retinopathy of prematurity (ROP). This retrospective cohort study included 591 neonates born with a gestational age (GA) ≤32 weeks and/or a birthweight (BW) ≤1500 g. Clinical data were retrospectively collected, and placentas were reexamined for acute (e.g. chorioamnionitis and funisitis) and chronic placental inflammation (e.g. chorioamnionitis, villitis of unknown etiology and chronic deciduitis). Severe acute chorioamnionitis was defined as the presence of confluent polymorphonuclear leukocytes or subchorionic microabscesses. Outcomes explored were GA, BW, small for gestational age (SGA), mechanical ventilation duration, postnatal corticosteroids, sepsis, necrotizing enterocolitis, and ROP. Acute histological chorioamnionitis and funisitis were associated with lower GA, lower SGA rates, increased duration of mechanical ventilation and increased ROP rates, while chronic chorioamnionitis and villitis were associated with higher GA and increased SGA rates. BW was significantly lower in neonates with chronic deciduitis. Subanalysis of placentas without maternal and fetal vascular malperfusion also showed increased rates of severe acute chorioamnionitis (42 % vs. 21 %), funisitis (61 % vs. 35 %) in neonates with ROP. Multivariable regression analysis revealed two placental inflammatory factors to be independently associated with ROP: severe acute chorioamnionitis (OR 2.1; 95 % CI 1.1-3.8) and funisitis (OR 1.7; 95 % CI 1.0-2.9). Structured placental evaluation of the presence of severe acute chorioamnionitis and funisitis is valuable in predicting the development of ROP. This increased risk of ROP development could be integrated into the neonatal treatment approach of high-risk neonates in a very early stage in order to reduce ROP.

Histological Chorioamnionitis and Funisitis as New Risk Factors for Retinopathy of Prematurity: A Meta-analysis

OBJECTIVE

 The role of placental inflammation in neonatal morbidities is underestimated due to lack of placental examination. This meta-analysis aims to assess the association between histological chorioamnionitis (HCA) with and without funisitis (FUN) and risk of retinopathy of prematurity (ROP).

STUDY DESIGN

 Forty-five studies reporting (unadjusted) data on HCA without FUN and HCA with FUN in neonates with ROP were included. Primary outcomes were any stage ROP and severe ROP. Potential confounders explored were gestational age (GA) at birth, birthweight, maternal steroid use, necrotizing enterocolitis, sepsis (suspected/proven) and mechanical ventilation duration.

RESULTS

 Neonates with HCA had increased risk for any stage ROP (odds ratio [OR] 1.8; 95% confidence interval [CI] 1.3-2.4) and severe ROP (OR 1.5; 95% CI 1.2-1.8) compared with neonates without HCA. The rates of any stage ROP (OR 1.8; 95% CI 1.4-2.2) and severe ROP (OR 1.4; 95% CI 1.1-1.6) were higher in neonates with FUN compared with neonates without FUN. Multivariate meta-regression analysis suggests that lower GA increases the effect size between FUN and severe ROP.

CONCLUSION

 This meta-analysis confirms that presence of HCA and FUN are risk factors for any stage ROP and severe ROP. Structured histological placental examination of HCA and FUN may be a tool to further refine the ROP risk profile.

KEY POINTS

· This systematic review confirms that HCA is a risk factor for ROP.. · This meta-analysis reveals that FUN results in an even higher risk for developing ROP.. · Placental examination of HCA/FUN may be a tool to further refine the ROP risk profile..

Ocular Vascular Diseases: From Retinal Immune Privilege to Inflammation

The eye is an immune privileged tissue that insulates the visual system from local and systemic immune provocation to preserve homeostatic functions of highly specialized retinal neural cells. If immune privilege is breached, immune stimuli will invade the eye and subsequently trigger acute inflammatory responses. Local resident microglia become active and release numerous immunological factors to protect the integrity of retinal neural cells. Although acute inflammatory responses are necessary to control and eradicate insults to the eye, chronic inflammation can cause retinal tissue damage and cell dysfunction, leading to ocular disease and vision loss. In this review, we summarized features of immune privilege in the retina and the key inflammatory responses, factors, and intracellular pathways activated when retinal immune privilege fails, as well as a highlight of the recent clinical and research advances in ocular immunity and ocular vascular diseases including retinopathy of prematurity, age-related macular degeneration, and diabetic retinopathy.

Identification of clinical factors associated with timing and duration of spontaneous regression of retinopathy of prematurity not requiring treatment

OBJECTIVE

Identify clinical factors that delay or prolong spontaneous regression of retinopathy of prematurity (ROP).

STUDY DESIGN

Secondary analysis of three prospective studies with 76 infants with ROP not requiring treatment, born ≤30 weeks postmenstrual age (PMA) and ≤1500 grams. Outcomes were PMA at greatest severity of ROP (PMA MSROP), at which regression began, at time of complete vascularization (PMA CV), and regression duration. Pearson's correlation coefficients, t-tests, or analyses of variance were calculated.

RESULTS

Increased positive bacterial cultures, hyperglycemia, transfusion volume of platelets and red blood cells and severity of ROP were associated with later PMA MSROP. Positive bacterial cultures, maternal chorioamnionitis, and less iron deficiency were associated with later PMA CV and prolonged regression duration. Slower length gain was associated with later PMA CV. P < 0.05 for all.

CONCLUSIONS

Preterm infants with inflammatory exposures or linear growth impairment may require longer surveillance for ROP resolution and complete vascularization.

Placental Findings in Infants Gestational Age < 34 Weeks and Impact on Short-Term Outcomes

AIM

To analyse placental changes in infants' gestational age < 34 weeks and its correlation to short-term respiratory outcomes or death until hospital discharge.

MATERIAL AND METHODS

Information regarding all in-house born preterm infants born before 34 weeks gestation and born from January 2009 until December 2014 were collected and included among others, placental pathology and relevant data on demographics and outcomes of infants.

RESULTS

Placental abnormalities was found in 157/253 (65.05%) cases. Acute placental inflammation was found to be the most common in both groups of premature neonates, followed by maternal vascular underperfusion. Maternal vascular underperfusion was significantly more common in GA ≤ 27 weeks compared to infants GA 28-33 weeks (35.2% vs. 13.7%; p = 0.018). Similarly, chronic placental inflammation was more common in infants GA ≤ 27 weeks compared to infants GA 28-33 weeks (14.3% vs. 3.3%; p = 0.014). Infants with placental pathology had a lower median birth weight (1460g vs. 1754g; p = 0.001, and were of shorter median GA at birth (31 vs. 32; p = 0.001). Infants with any placental disease had higher rates of death until hospital discharge (10.2% vs. 3.1%; p = 0.039) and higher rates of any stage of bronchopulmonary dysplasia (41.4% vs. 26.0%; p = 0.013). There were no significant differences in mechanical ventilation rates, duration of mechanical ventilation and duration of supplemental oxygen therapy.

CONCLUSION

Identifiable placental abnormalities were found in most infants born < 34 weeks gestation. Placental pathology is associated with increased rates of bronchopulmonary dysplasia and death until hospital discharge.

Retinopathy of prematurity and placental histopathology findings: A retrospective cohort study

Aim

Retinopathy of prematurity (ROP) is a biphasic vaso-proliferative disease that has the potential to cause blindness. In addition to prematurity and hyperoxia, perinatal infection and inflammation have been reported to play a critical role in the pathogenesis of ROP. The aim of this study was to assess the association between placental inflammation and the severity of ROP.

Methods

A retrospective study of infants (<30 weeks of gestational age) born at the King Edward Memorial Hospital, a tertiary perinatal center in Western Australia.

Results

A total of 878 infants were included in this study (ROP stage 0-2 = 829; 3 or more = 49). The presence of maternal chorioamnionitis appeared to show signs of an association with reduced odds of severe ROP: mild chorioamnionitis OR=0.43 (95% CI: 0.17, 1.05) and severe chorioamnionitis OR=0.68 (95% CI: 0.29, 1.60). A strong association was observed for oxygen supplementation at 36 weeks (OR: 5.16; p < 0.001), exposure to postnatal steroids (OR: 6.65; p < 0.001), and receipt of platelet transfusion (OR: 8.21; p < 0.001).

Conclusion

Maternal chorioamnionitis or fetal chorioamnionitis was associated with reduced odds of severe ROP. A strong association was found in infants who needed oxygen supplementation at 36 weeks and those who required steroids or platelets in the postnatal period.

Diallyl Trisulfide Promotes Placental Angiogenesis by Regulating Lipid Metabolism and Alleviating Inflammatory Responses in Obese Pregnant Mice

The placental tissue serves as an exchanger between the mother and the fetus during pregnancy in mammals. Proper placental angiogenesis is central to the health of both the mother and the growth and development of the fetus. Maternal obesity is associated with impaired placental function, resulting in restricted placental blood vessel development and fetal developmental disorders. Hydrogen sulfide (H₂S) is a ubiquitous second messenger in cells that has many biological effects such as promoting angiogenesis, anti-inflammation, anti-oxidation and promoting lipid metabolism. However, in the case of maternal obesity, whether H₂S can be used as an important signaling molecule to regulate body metabolism, alleviate placental inflammation levels and promote placental angiogenesis is still unclear. In this study, diallyl trisulfide (DATS), which is a well-known H₂S donor, was derived from garlic and used to treat obese pregnant mice induced by a high-fat diet, to determine its effects on lipid metabolism and inflammation, as well as placental morphology and placental angiogenesis. Here, we show that DATS treatment increased litter size and alive litter size. DATS improved the H₂S level in the serum and placenta of the mice. In addition, DATS treatment improved insulin resistance and lipid metabolism, reduced the inflammatory response and alleviated placental vascular dysplasia caused by obesity in obese mice. In summary, our research revealed that H₂S is an important signaling molecule in vivo, which can regulate placental angiogenesis and improve the reproductive performance in maternal obesity. The addition of H₂S donor DATS during pregnancy promoted placental angiogenesis by regulating lipid metabolism and alleviating inflammatory responses in obese pregnant mice.

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.

Development of the genomic inflammatory index (GII) to assess key maternal antecedents associated with placental inflammation

INTRODUCTION

Placental inflammation is associated with a variety of adverse health outcomes, including poor pregnancy outcomes as well as later in life health. The current clinical methodologies for evaluating placental histology for inflammation are limited in their sensitivity. The objective of this study was to develop a genomic inflammatory index (GII) that can be utilized as a biomarker to effectively quantify and evaluate placental inflammation.

METHODS

RNA-sequencing of n = 386 placentas from the Extremely Low Gestational Age Newborn (ELGAN) cohort was conducted. Transcriptional data for a biologically-targeted set of 14 genes, selected for their established role in pro-inflammatory signaling pathways, were aggregated to construct the GII. Multiple linear regression models were used to examine relationships between 47 perinatal factors and the GII.

RESULTS

The GII demonstrated a nine-fold difference across subjects and displayed positive trends with other indicators of placental inflammation. Significant differences in the GII were observed for race where women who self-identified as Black displayed higher levels of placental inflammation than those who self-identified as White women (p < 0.001). Additionally, married Black women showed reduced placental inflammation compared to those who were unmarried (beta value: 0.828, p-value: 0.032). Placentas from women who were treated with steroids during the delivery of the infant displayed higher GII levels than those who were not (p = 0.023).

DISCUSSION

Overall, the GII demonstrated an association between various perinatal factors and placental inflammation. It is anticipated that the GII will provide a novel genomics tool for quantifying placental inflammation, allowing for further investigation of causes, and ultimately the prevention, of inflammation in the placenta.

The potential of marine resources for retinal diseases: a systematic review of the molecular mechanisms

We rely on vision more than on any other sense to obtain information about our environment. Hence, the loss or even impairment of vision profoundly affects our quality of life. Diet or food components have already demonstrated beneficial effects on the development of retinal diseases. Recently, there has been a growing interest in resources from marine animals and plants for the prevention of retinal diseases through nutrition. Especially fish intake and omega-3 fatty acids have already led to promising results, including associations with a reduced incidence of retinal diseases. However, the underlying molecular mechanisms are insufficiently explained. The aim of this review was to summarize the known mechanistic effects of marine resources on the pathophysiological processes in retinal diseases. We performed a systematic literature review following the PRISMA guidelines and identified 107 studies investigating marine resources in the context of retinal diseases. Of these, 46 studies described the underlying mechanisms including anti-inflammatory, antioxidant, antiangiogenic/vasoprotective, cytoprotective, metabolic, and retinal function effects, which we critically summarize. We further discuss perspectives on the use of marine resources for human nutrition to prevent retinal diseases with a particular focus on regulatory aspects, health claims, safety, and bioavailability.

Risk Factors Associated with Retinopathy of Prematurity in Very and Extremely Preterm Infants

Background and Objectives: Retinopathy of prematurity (ROP) is the leading cause of blindness in preterm infants. We studied the relationship between different perinatal characteristics, i.e., sex; gestational age (GA); birth weight (BW); C-reactive protein (CRP) and lactate dehydrogenase (LDH) concentrations; ventilation, continuous positive airway pressure (CPAP), and surfactant administration; and the incidence of Stage 1–3 ROP. Materials and Methods: This study included 247 preterm infants with gestational age (GA) < 32 weeks that were successfully screened for ROP. Univariate and multivariate binary analyses were performed to find the most significant risk factors for ROP (Stage 1–3), while multivariate multinomial analysis was used to find the most significant risk factors for specific ROP stages, i.e., Stage 1, 2, and 3. Results: The incidence of ROP (Stage 1–3) was 66.40% (164 infants), while that of Stage 1, 2, and 3 ROP was 15.38% (38 infants), 27.53% (68 infants), and 23.48% (58 infants), respectively. Following univariate analysis, multiple perinatal characteristics, i.e., GA; BW; and ventilation, CPAP, and surfactant administration, were found to be statistically significant risk factors for ROP (p < 0.001). However, in a multivariate model using the same characteristics, only BW and ventilation were significant ROP predictors (p < 0.001 and p < 0.05, respectively). Multivariate multinomial analysis revealed that BW was only significantly correlated with Stage 2 and 3 ROP (p < 0.05 and p < 0.001, respectively), while ventilation was only significantly correlated with Stage 2 ROP (p < 0.05). Conclusions: The results indicate that GA; BW; and the use of ventilation, CPAP, and surfactant were all significant risk factors for ROP (Stage 1–3), but only BW and ventilation were significantly correlated with ROP and specific stages of the disease, namely Stage 2 and 3 ROP and Stage 2 ROP, respectively, in multivariate models.

Efficacy of Aflibercept Treatment and Its Effect on the Retinal Perfusion in the Oxygen-Induced Retinopathy Mouse Model of Retinopathy of Prematurity

INTRODUCTION

Bevacizumab and ranibizumab, which are anti-vascular endothelial growth factor (VEGF) medications, are used frequently in the treatment for retinopathy of prematurity (ROP) in infants. Aflibercept, or VEGF Trap, has been used anecdotally, but translation and clinical studies are lacking.

OBJECTIVE

This study investigates the efficacy of aflibercept at reducing areas of non-perfused retina and studies its effect on normal angiogenesis in the oxygen-induced retinopathy mouse model of ROP.

METHODS

C57BL/6 J mice were assigned to room air control (n = 21 eyes) or hyperoxia with 75% oxygen (n = 84 eyes). The hyperoxic mice were assigned to 1 of 3 groups: 0 ng (n = 14 eyes), 100 ng (n = 35 eyes), or 1,000 ng (n = 35 eyes) of intravitreal aflibercept administered on postnatal day 14. Eyes were enucleated at PN17 and PN25 postinjection. Retinas were stained with anti-collagen IV antibody and photographed with microscopy. Areas of perfused and non-perfused retina were quantified using ImageJ software. Statistical comparisons were made using ANOVA with Tukey post hoc comparisons.

RESULTS

At PN17, there was no significant difference in the area of non-perfused retina between the hyperoxic control and the 100 and 1,000 ng aflibercept groups. At PN25, the 100 ng (p < 0.05) and 1,000 ng (p = 0.008) treatment groups displayed less non-perfusion compared to hyperoxic controls. At the 1,000 ng dose, there was increased non-perfusion compared to the 100 ng dose (p = 0.02). There was reduced non-perfusion by PN25 compared to PN17 for the 100 ng group (p < 0.05), with no difference in the 1,000 ng group.

CONCLUSIONS

The study shows that the area of non-perfused retina decreases effectively with aflibercept at PN25 with 100 ng dosage. With the 1,000 ng dosage, there is an inhibition of the physiologic angiogenesis with a higher area of non-perfused retina.

A pilot randomised clinical trial of 670 nm red light for reducing retinopathy of prematurity

BACKGROUND

Photobiomodulation by 670 nm red light in animal models reduced severity of ROP and improved survival. This pilot randomised controlled trial aimed to provide data on 670 nm red light exposure for prevention of ROP and survival for a larger randomised trial.

METHODS

Neonates <30 weeks gestation or <1150 g at birth were randomised to receive 670 nm for 15 min (9 J/cm²) daily until 34 weeks corrected age.

DATA COLLECTED

placental pathology, growth, days of respiratory support and oxygen, bronchopulmonary dysplasia, patent ductus arteriosus, necrotising enterocolitis, sepsis, worst stage of ROP, need for laser treatment, and survival.

RESULTS

Eighty-six neonates enrolled-45 no red light; 41 red light. There was no difference in severity of ROP (<27 weeks-p = 0.463; ≥27 weeks-p = 0.558) or requirement for laser treatment (<27 weeks-p = 1.00; ≥27 weeks-no laser treatment in either group). Survival in 670 nm red light treatment group was 100% (41/41) vs 89% (40/45) in untreated infants (p = 0.057).

CONCLUSION

Randomisation to receive 670 nm red light within 24-48 h after birth is feasible. Although no improvement in ROP or survivability was observed, further testing into the dosage and delivery for this potential therapy are required.

Cumulative evidence for association of sepsis and retinopathy of prematurity

BACKGROUND

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease affected by multiple factors such as infection and preterm birth. The role of sepsis in the development of ROP remains controversial. This systematic review and meta-analysis aimed to identify the impact of sepsis on ROP.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched using terms related to sepsis and ROP. Cohort or case-control studies that reported the association of sepsis and ROP were eligible. The odds ratios (ORs) together with the 95% confidence interval (CI) were extracted from the studies or computed by authors if not provided.

RESULTS

Thirty-four studies were ultimately included in this meta-analysis. The pooled results showed that sepsis increased the risk for the development of any stage ROP (OR = 2.16; 95% CI: 1.65-2.82). Both early onset (OR = 2.50; 95% CI: 1.97-3.18) and late-onset (OR = 1.37; 95% CI: 1.22-1.55) sepsis were associated with severe ROP. Furthermore, both bacterial sepsis (OR = 1.74; 95% CI: 1.21-2.50) and fungal sepsis (OR = 2.96; 95% CI: 2.05-4.28) were also found to be associated with severe ROP.

CONCLUSION

Sepsis increased the risk of any stage ROP, especially for the severe ROP. Further high-quality clinical studies are needed to eliminate heterogeneity and publication bias to validate these findings.

Exercise prevents the adverse effects of maternal obesity on placental vascularization and fetal growth

KEY POINTS

Maternal exercise improves the metabolic health of maternal mice challenged with a high-fat diet. Exercise intervention of obese mothers prevents fetal overgrowth. Exercise intervention reverses impaired placental vascularization in obese mice. Maternal exercise activates placental AMP-activated protein kinase, which was inhibited as a result of maternal obesity.

ABSTRACT

More than one-third of pregnant women in the USA are obese and maternal obesity (MO) negatively affects fetal development, which predisposes offspring to metabolic diseases. The placenta mediates nutrient delivery to fetuses and its function is impaired as a result of MO. Exercise ameliorates metabolic dysfunction resulting from obesity, although its effect on placental function of obese mothers has not been explored. In the present study, C57BL/6J female mice were randomly assigned into two groups fed either a control or a high-fat diet (HFD) and then the mice on each diet were further divided into two subgroups with/without exercise. In HFD-induced obese mice, daily treadmill exercise during pregnancy reduced body weight gain, lowered serum glucose and lipid concentration, and improved insulin sensitivity of maternal mice. Importantly, maternal exercise prevented fetal overgrowth (macrosomia) induced by MO. To further examine the preventive effects of exercise on fetal overgrowth, placental vascularization and nutrient transporters were analysed. Vascular density and the expression of vasculogenic factors were reduced as a result of MO but were recovered by maternal exercise. On the other hand, the contents of nutrient transporters were not substantially altered by MO or exercise, suggesting that the protective effects of exercise in MO-induced fetal overgrowth were primarily a result of the alteration of placental vascularization and improved maternal metabolism. Furthermore, exercise enhanced downstream insulin signalling and activated AMP-activated protein kinase in HFD placenta. In sum, maternal exercise prevented fetal overgrowth induced by MO, which was associated with improved maternal metabolism and placental vascularization in obese mothers with exercise.