Serum concentrations of cytokines in infants with retinopathy of prematurity

The association between serum 25-hydroxyvitamin D levels and retinopathy of prematurity in preterm infants

Objective

This study aimed to investigate the correlation between serum 25-hydroxyvitamin D (25(OH)D) levels and retinopathy of prematurity (ROP) in premature infants one month after birth.

Methods

Preterm infants (gestational age <32 weeks) admitted to the Affiliated Hospital of Qingdao University from 2017 to 2022 were divided into ROP and non-ROP groups based on ROP occurrence any stage. Serum 25(OH)D levels and clinical data were compared between the two groups at 1 month after birth, and the relationship between vitamin D levels and ROP was analyzed.

Results

Among the 217 premature infants included, 55 (25.35%) were in the ROP group, and 162 (74.65%) were in the non-ROP group. The ROP group had lower gestational age and birth weight, longer invasive ventilation (IV), non-invasive ventilation (NIV), and oxygen therapy times compared to the non-ROP group. Apgar scores, cesarean delivery, and antenatal steroids ratios were lower in the ROP group, while sepsis and pulmonary surfactant utilization ratios were higher (all p < 0.05). Significant differences in serum 25-(OH)D levels were observed among children in the non-ROP group (14.20 ± 5.07 ng/ml), ROP treated group (7.891 ± 1.878 ng/ml), and untreated group (12.168 ± 4.354 ng/ml) (p < 0.001). Multivariate regression analysis identified antenatal steroids as protective factors and lower birth weight, serum 25-(OH)D levels, long-term invasive mechanical ventilation, and sepsis as independent risk factors for ROP in premature infants.

Conclusion

Vitamin D, lower birth weight, long-term invasive mechanical ventilation, and sepsis were associated with incidence of ROP in preterm infants. Vitamin D was associated with the severity of ROP, emphasizing the importance of prudent vitamin D supplementation and regular monitoring of serum 25-(OH)D levels.

Tear fluid cytokine analysis: a non-invasive approach for assessing retinopathy of prematurity severity

PURPOSE

To determine whether there is a significant association between inflammatory cytokines in the tear fluid and the severity of Retinopathy of Prematurity (ROP).

STUDY DESIGN

Retrospective cohort study.

METHODS

The cytokine levels in tear fluids were determined in 34 eyes with ROP and 18 eyes without ROP. There were 15 eyes with severe ROP requiring treatment and 19 eyes with mild ROP not requiring treatment. For severe ROP eyes, tear fluids were collected before treatment.

RESULTS

Significantly higher levels of CCL2 and vascular endothelial growth factor (VEGF) were detected in eyes with severe ROP compared to eyes with mild ROP and no ROP. When assessed for cytokine levels that discriminate each disease group, CCL2 showed a significant odds ratio of 1.76 for severity change (/quintile, P = 0.032, after adjusting for birth weight). Correlation analysis showed that birth weight correlated with IL-1α levels, and decreased weight gain increased IFN-γ levels. We next determined tear fluid cytokines which discriminate severe ROP using receiver operating characteristics' analysis. We found that combination of higher CCL2 levels, higher VEGF levels, and lower IFN-γ levels in the tear fluid had a stronger predictive value for severe ROP (area under curve, 0.85).

CONCLUSION

The levels of CCL2, VEGF, and IFN-γ in tear fluid may serve as useful biomarkers for assessing the severity of ROP.

Predictive role of systemic immune-inflammation index and neutrophil/lymphocyte ratio values in infants with retinopathy of prematurity

PURPOSE

To search the relationship between serum neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and systemic immune-inflammation index (SII) values with the development of retinopathy of prematurity (ROP) and the requirement for laser treatment.

METHODS

This retrospective cohort study was carried out with 195 preterm infants between 2012 and 2023. The NLR, PLR, LMR, and SII values were calculated on both the first day and at the end of the first month after birth. The association between development of ROP and other risk factors were analyzed using univariate analysis and multivariate logistic regression analysis.

RESULTS

Of patients, 92 infants were diagnosed with ROP. Laser treatment was administered to 36 infants. The postnatal first-day NLR and SII values were higher in infants with ROP than in infants without ROP (p < 0.001 for both). Postnatal first-month NLR, LMR, and SII values were higher in infants with ROP (p < 0.001, p = 0.007, and p < 0.001, respectively). In multivariate analyses, postnatal first-day NLR and first-month LMR values were regarded as independent risk factors for the development of ROP (OR:8.867 and 1.286, p = 0.002 and p = 0.009, respectively). In multivariate analyses performed for laser treatment requirement, postnatal first-month PLR and SII values were determined as independent risk factors (OR:0.951 and 1.011, respectively, p = 0.004 for both).

CONCLUSIONS

Postnatal first-day NLR and first-month LMR values were determined as independent risk factors for the development of ROP. For the requirement of laser treatment, the postnatal first-month PLR and SII values were determined as independent risk factors.

Neonatal sepsis as a cause of retinopathy of prematurity: An etiological explanation

Retinopathy of prematurity (ROP) is a complex neonatal disorder with multiple contributing factors. In this paper we have mounted the evidence in support of the proposal that neonatal sepsis meets all requirements for being a cause of ROP (not a condition, mechanism, or even innocent bystander) by means of initiating the early stages of the pathomechanism of ROP occurrence, systemic inflammation. We use the model of etiological explanation, which distinguishes between two overlapping processes in ROP causation. It can be shown that sepsis can initiate the early stages of the pathomechanism via systemic inflammation (causation process) and that systemic inflammation can contribute to growth factor aberrations and the retinal characteristics of ROP (disease process). The combined contribution of these factors with immaturity at birth (as intrinsic risk modifier) and prenatal inflammation (as extrinsic facilitator) seems to provide a cogent functional framework of ROP occurrence. Finally, we apply the Bradford Hill heuristics to the available evidence. Taken together, the above suggests that neonatal sepsis is a causal inducer of ROP.

Systems levels analysis of lipid metabolism in oxygen-induced retinopathy

Hyperoxia induces glutamine-fueled anaplerosis in the Muller cells, endothelial cells, and retinal explants. Anaplerosis takes away glutamine from the biosynthetic pathway to the energy-producing TCA cycle. This process depletes biosynthetic precursors from newly proliferating endothelial cells. The induction of anaplerosis in the hyperoxic retina is a compensatory response, either to decreased glycolysis or decreased flux from glycolysis to the TCA cycle. We hypothesized that by providing substrates that feed into TCA, we could reverse or prevent glutamine-fueled anaplerosis, thereby abating the glutamine wastage for energy generation. Using an oxygen-induced retinopathy (OIR) mouse model, we first compared the difference in fatty acid metabolism between OIR-resistant BALB/cByJ and OIR susceptible C57BL/6J strains to understand if these strains exhibit metabolic difference that protects BALB/cByJ from the hyperoxic conditions and prevents their vasculature in oxygen-induced retinopathy model. Based on our findings from the metabolic comparison between two mouse strains, we hypothesized that the medium-chain fatty acid, octanoate, can feed into the TCA and serve as an alternative energy source in response to hyperoxia. Our systems levels analysis of OIR model shows that the medium chain fatty acid can serve as an alternative source to feed TCA. We here, for the first time, demonstrate that the retina can use medium-chain fatty acid octanoate to replenish TCA in normoxic and at a higher rate in hyperoxic conditions.

Early detection and correlation of tear fluid inflammatory factors that influence angiogenesis in premature infants with and without retinopathy of prematurity

Purpose

To measure the levels of inflammatory factors in tear fluid of pre-term infants with and without retinopathy of prematurity (ROP).

Methods

The cross-sectional pilot study included 29 pre-term infants undergoing routine ROP screening. Pre-term infants were grouped as those without ROP (no ROP; n = 14) and with ROP (ROP; n = 15). Sterile Schirmer's strips were used to collect the tear fluid from pre-term infants. Inflammatory factors such as interleukin (IL)-6, IL-8, MCP1 (Monocyte Chemoattractant Protein 1; CCL2), RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted; CCL5), and soluble L-selectin (sL-selectin) were measured by cytometric bead array using a flow cytometer.

Results

Birth weight (BW) and gestation age (GA) were significantly (P < 0.05) lower in pre-term infants with ROP compared with those without ROP. Higher levels of RANTES (P < 0.05) and IL-8 (P = 0.09) were observed in the tear fluid of pre-term infants with ROP compared with those without ROP. Lower levels of tear fluid IL-6 (P = 0.14) and sL-selectin (P = 0.18) were measured in pre-term infants with ROP compared with those without ROP. IL-8 and RANTES were significantly (P < 0.05) higher in the tear fluid of pre-term infants with stage 3 ROP compared with those without ROP. Tear fluid RANTES level was observed to be inversely associated with GA and BW of pre-term infants with ROP and not in those without ROP. Furthermore, the area under the curve and odds ratio analysis demonstrated the relevance of RANTES/BW (AUC = 0.798; OR-7.2) and RANTES/MCP1 (AUC = 0.824; OR-6.8) ratios in ROP.

Conclusions

Distinct changes were observed in the levels of tear inflammatory factors in ROP infants. The status of RANTES in ROP suggests its possible role in pathobiology and warrants further mechanistic studies to harness it in ROP screening and management.

Cord blood transforming growth factor-β-induced as predictive biomarker of retinopathy of prematurity in preterm infants

PURPOSE

To determine whether 14 inflammation-, angiogenesis-, and adhesion-related proteins in cord blood (CB), alone or in combination with conventional perinatal factors, could predict retinopathy of prematurity (ROP) in preterm infants.

METHODS

Data from 111 preterm infants (born at ≤ 32.0 weeks) were retrospectively reviewed. The levels of endoglin, E-selectin, HSP70, IGFBP-3/4, LBP, lipocaline-2, M-CSFR, MIP-1α, pentraxin 3, P-selectin, TGFBI, TGF-β1, and TNFR2 were assessed in stored CB samples collected at birth using ELISA kits. The primary endpoints included severe ROP (≥ stage 3) and type 1 ROP requiring treatment.

RESULTS

ROP was diagnosed in 29 infants (26.1%), among whom 14 (12.6%) had severe ROP and seven (6.3%) had type 1 ROP. Multivariate logistic regression showed that decreased CB TGFBI levels were significantly associated with severe ROP and type 1 ROP after adjusting for gestational age at birth. Stepwise regression analysis allowed to design prediction models with good accuracy, which comprised low CB TGFBI levels and low birth weight (BW) as predictors for severe ROP (area under the curve [AUC] = 0.888), and low CB endoglin levels and low BW as predictors for type 1 ROP (AUC = 0.950). None of the other CB proteins evaluated were found to be associated with severe ROP or type 1 ROP.

CONCLUSIONS

Low CB TGFBI levels are associated with severe ROP and type 1 ROP, independently of gestational age. Moreover, combined predictive models based on CB TGFBI and endoglin levels, along with BW data, may act as good indicators at birth for the neonatal risk of ROP progression.

A novel marker for predicting type 1 retinopathy of prematurity: C-reactive protein/albumin ratio

PURPOSE

We aimed to investigate whether the C-reactive protein (CRP) to albumin ratio (CAR) an inflammatory predictor can be used as a marker for the development of ROP.

METHODS

Gestational age, birth weight, gender, neonatal, and maternal risk factors were recorded. The patients were divided into two groups: those who did not develop ROP (ROP -) and those who developed ROP (ROP +). The ROP + group was further separated into two groups: those who required treatment (ROP + T) and those who were not treated (ROP + NT). The following parameters were noted in the first postnatal week and at the end of the first postnatal month: CRP, albumin, CAR, white blood cell (WBC), neutrophil, lymphocyte, neutrophil-to-lymphocyte ratio (NLR), distribution red cell width (RDW), platelet (Plt), and RDW/platelet ratio.

RESULTS

We evaluated 131 premature infants who met the inclusion criteria. There was no difference between the main groups in hemogram parameters and CAR at the postnatal first week. WBC count (p = 0.011), neutrophil count (p = 0.002), and NLR were high (p = 0.004) in the ROP + group at the end of the postnatal 1st month. The CAR level at the end of the first month was higher in the ROP + group (p = 0.027). CAR was similar between the ROP + T and ROP + NT groups (p = 0.112) in the postnatal first week but higher in the treatment-required group at the end of the first month (p < 0.01).

CONCLUSION

High CAR and high NLR at the end of the postnatal first month can be used to predict the development of severe ROP.

CD8+ T Cells Promote Pathological Angiogenesis in Ocular Neovascular Disease

BACKGROUND

CD4⁺ (cluster of differentation) and CD8⁺ T cells are increased in the ocular fluids of patients with neovascular retinopathy, yet their role in the disease process is unknown.

METHODS

We describe how CD8⁺ T cells migrate into the retina and contribute to pathological angiogenesis by releasing cytokines and cytotoxic factors.

RESULTS

In oxygen-induced retinopathy, flow cytometry revealed the numbers of CD4⁺ and CD8⁺ T cells were increased in blood, lymphoid organs, and retina throughout the development of neovascular retinopathy. Interestingly, the depletion of CD8⁺ T cells but not CD4⁺ T cells reduced retinal neovascularization and vascular leakage. Using reporter mice expressing gfp (green fluorescence protein) in CD8⁺ T cells, these cells were localized near neovascular tufts in the retina, confirming that CD8⁺ T cells contribute to the disease. Furthermore, the adoptive transfer of CD8⁺ T cells deficient in TNF (tumor necrosis factor), IFNγ (interferon gamma), Prf (perforin), or GzmA/B (granzymes A/B) into immunocompetent Rag1^-/- mice revealed that CD8⁺ T cells mediate retinal vascular disease via these factors, with TNF influencing all aspects of vascular pathology. The pathway by which CD8⁺ T cells migrate into the retina was identified as CXCR3 (C-X-C motif chemokine receptor 3) with the CXCR3 blockade reducing the number of CD8⁺ T cells within the retina and retinal vascular disease.

CONCLUSIONS

We discovered that CXCR3 is central to the migration of CD8⁺ T cells into the retina as the CXCR3 blockade reduced the number of CD8⁺ T cells within the retina and vasculopathy. This research identified an unappreciated role for CD8⁺ T cells in retinal inflammation and vascular disease. Reducing CD8⁺ T cells via their inflammatory and recruitment pathways is a potential treatment for neovascular retinopathies.

Blood neutrophil-to-lymphocyte ratio as a risk factor in treatment for retinopathy of prematurity

PURPOSE

To investigate the blood neutrophil-to-lymphocyte ratio (NLR) as a risk factor for retinopathy of prematurity (ROP) development or treatment.

METHODS

Retrospective cohort study. Infants who underwent ROP screening at Shiga University of Medical Science Hospital and Omihachiman Community Medical Center between April 2010 and December 2021 were included in this study. Screening criteria were gestational age (GA) < 32 weeks or birth weight (BW) < 1500 g. Multivariate logistic regression analysis was applied to investigate whether the NLR constituted an independent risk factor for ROP development or treatment. The objective variable was ROP development or treatment, and the explanatory variables were GA, BW, NLR, maternal infection or clinical chorioamnionitis and corticosteroid use by the mother. Maternal infection or clinical chorioamnionitis and corticosteroid use by the mother was included in the explanatory variables to adjust for factors affecting the NLR.

RESULTS

In total, 220 infants met the inclusion criteria, of whom 125 developed ROP, whereas 95 infants did not display ROP. GA was significantly associated with ROP development (odds ratio (OR): 0.41, p < 0.001); however, the NLR was not significantly associated with ROP development (OR: 1.0, p = 0.74). Thirty-eight infants received treatment for ROP, whereas 182 infants had no such treatment. BW and the NLR were significantly associated with ROP treatment (OR: 1.6 and 0.66, p < 0.001 and 0.003, respectively).

CONCLUSION

The NLR was not a risk factor for ROP development but was a risk factor for ROP treatment.

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.

The Determinative Role of Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a neonatal disease corresponding to vision impairment and blindness. Utilizing the pathogenesis of ROP and the risk factors affecting its progression can help prevent and reduce its incidence and lead to the emergence and development of new treatment strategies. Factors influencing retinopathy include growth and inflammatory factors that play an essential role in the pathogenesis of the ROP. This review summarizes the most critical factors in the pathogenesis of ROP.

Retinopathy of prematurity: contribution of inflammatory and genetic factors

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disorder that represents an important cause of childhood visual impairment and blindness. Although oxidative stress has long been implicated in ROP etiology, other prenatal and perinatal factors are also involved. This review focuses on current research involving inflammation and genetic factors in the pathogenesis of ROP. Increasing evidence suggests that perinatal inflammation or infection contributes to ROP pathogenesis. Cytokines and chemokines with a fundamental role in inflammatory responses and that significantly contributing to angiogenesis are analyzed. Microglia cells, the retinal-resident macrophages, are crucial for retinal homeostasis, however, under sustained pathological stimuli release exaggerated amounts of inflammatory mediators and can promote pathological neovascularization. Current modulation of angiogenic cytokines, such as treatment with antibodies to vascular endothelial growth factor (anti-VEGF), has shown efficacy in the treatment of ocular neovascularization; however, some patients are refractory to anti-VEGF agents, suggesting that other angiogenic or anti-angiogenic cytokines need to be identified. Much evidence suggests that genetic factors contribute to the phenotypic variability of ROP. Several studies have implicated the involvement of candidate genes from different signaling pathways in the development of ROP. However, a genetic component with a major impact on ROP has not yet been discovered. Most studies have limitations and did not replicate results. Future research involving bioinformatics, genomics, and proteomics may contribute to finding more genes associated with ROP and may allow discovering better solutions in the management and treatment of ROP.

Sex-specific cytokine responses and neurocognitive outcome after blood transfusions in preterm infants

BACKGROUND

The objective of this study was to determine sex-specific differences in inflammatory cytokine responses to red blood cell (RBC) transfusion in preterm infants in the neonatal period and their relationship to later neurocognitive status.

METHODS

Infants with a birth weight <1000 g and gestational age 22-29 weeks were enrolled in the Transfusion of Prematures (TOP) trial. The total number of transfusions was used as a marker of transfusion status. Nineteen cytokines and biomarkers were analyzed from 71 infants longitudinally during the neonatal period. Twenty-six infants completed the Bayley Scales of Infant & Toddler Development, 3rd Edition (Bayley-III) at 12 months' corrected age.

RESULTS

Nine cytokine levels were significantly elevated in proportion to the number of transfusions received. Of those, one cytokine showed a sex-specific finding (p = 0.004): monocyte chemoattractant protein-1, MCP-1, rose substantially in females (8.9% change per additional transfusion), but not in males (-0.8% change). Higher concentrations of MCP-1 exclusively were associated with worse Bayley-III scores: decreased cognitive raw scores (p = 0.0005) and motor scaled scores (p < 0.0001).

CONCLUSIONS

This study provides evidence of a sex-specific difference in the inflammatory response to RBC transfusions during neonatal life, with MCP-1 levels rising only in females and inversely correlating with neurocognitive status at 12 months old.

IMPACT

It is important to understand the risk factors for abnormal neurodevelopment in preterm infants, including anemia and RBC transfusion, in order to improve outcomes and provide potential targets for therapy. Our study investigates and provides the first evidence of sex-specific differences in inflammatory cytokine responses to RBC transfusions in preterm infants in the neonatal period, and their relationship to later cognitive outcomes. This study critically suggests that different transfusion thresholds may have a sex-specific effect on neurodevelopment: females have worse cognitive outcomes with increased number of transfusions, while males have worse outcomes with lower number of transfusions.

Novel Potential Biomarkers for Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is the main risk factor for vision-threatening disease in premature infants with low birth weight. An accumulating number of independent studies have focused on ROP pathogenesis and have demonstrated that laser photocoagulation therapy and/or anti-VEGF treatment are effective. However, early diagnosis of ROP is still critical. At present, the main method of ROP screening is based on binocular indirect ophthalmoscopy. However, the judgment of whether ROP occurs and whether treatment is necessary depends largely on ophthalmologists with a great deal of experience. Therefore, it is essential to develop a simple, accurate and effective diagnostic method. This review describes recent findings on novel biomarkers for the prediction, diagnosis and prognosis of ROP patients. The novel biomarkers were separated into the following categories: metabolites, cytokines and growth factors, non-coding RNAs, iconography, gut microbiota, oxidative stress biomarkers, and others. Biomarkers with high sensitivity and specificity are urgently needed for the clinical applications of ROP. In addition, using non-invasive or minimally invasive methods to obtain samples is also important. Our review provides an overview of potential biomarkers of ROP.

Correlation between systemic immune-inflammation index and routine hemogram-related inflammatory markers in the prognosis of retinopathy of prematurity

Purpose:

To evaluate the prognostic potential of systemic inflammatory index in the course of retinopathy of prematurity (ROP).

Methods:

This is a retrospective case-control study. 303 infants with a gestational age of ≤35 weeks were screened with and without ROP at birth and 1 month after the birth of complete blood counts (CBC) were included in this study. Serum neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte (PLR), and systemic immune-inflammation index (SII) was calculated at birth and one month after. LMR was calculated by dividing the absolute lymphocyte count by the absolute monocyte count. NLR and PLR were determined by dividing the absolute neutrophil count or the absolute platelet count by the absolute lymphocyte count, respectively. The SII was calculated by the formula = neutrophilxplatelet/lymphocyte. All statistical analyses were performed using SPSS 22 (SPSS for Windows, version 22.0; SPSS, Inc. Chicago, IL, USA).

Results:

A total of 303 infants were included 145 with ROP and 158 without ROP. The NLR, LMR, PLR and SII values were 0.56 ± 1.17/0.51 ± 1.04 (P = 0.997), 13.7 ± 18/9.49 ± 13.1 (P = 0.014), 31.69 ± 68/24.1 ± 37.7 (P = 0.268), 131.42 ± 326/124.66 ± 267 (P = 0.935) in with ROP and without ROP infant at birth respectively. The NLR, LMR, PLR, and SII values were 0.68 ± 1.27/0.34 ± 0.99 (P = 0.001), 2.58 ± 6.01/2.46 ± 14.5 (P = 0.706), 47.5 ± 78.33/33.55 ± 42.4 (P = 0.035), and 253 ± 681/114 ± 345 (P = 0.001), respectively in with ROP and without ROP infant at 1 month after birth.

Conclusion:

The NLR, PLR, and SII seem an independent predictor of the development of ROP.

The fetal inflammatory response syndrome: the origins of a concept, pathophysiology, diagnosis, and obstetrical implications

The fetus can deploy a local or systemic inflammatory response when exposed to microorganisms or, alternatively, to non-infection-related stimuli (e.g., danger signals or alarmins). The term "Fetal Inflammatory Response Syndrome" (FIRS) was coined to describe a condition characterized by evidence of a systemic inflammatory response, frequently a result of the activation of the innate limb of the immune response. FIRS can be diagnosed by an increased concentration of umbilical cord plasma or serum acute phase reactants such as C-reactive protein or cytokines (e.g., interleukin-6). Pathologic evidence of a systemic fetal inflammatory response indicates the presence of funisitis or chorionic vasculitis. FIRS was first described in patients at risk for intraamniotic infection who presented preterm labor with intact membranes or preterm prelabor rupture of the membranes. However, FIRS can also be observed in patients with sterile intra-amniotic inflammation, alloimmunization (e.g., Rh disease), and active autoimmune disorders. Neonates born with FIRS have a higher rate of complications, such as early-onset neonatal sepsis, intraventricular hemorrhage, periventricular leukomalacia, and death, than those born without FIRS. Survivors are at risk for long-term sequelae that may include bronchopulmonary dysplasia, neurodevelopmental disorders, such as cerebral palsy, retinopathy of prematurity, and sensorineuronal hearing loss. Experimental FIRS can be induced by intra-amniotic administration of bacteria, microbial products (such as endotoxin), or inflammatory cytokines (such as interleukin-1), and animal models have provided important insights about the mechanisms responsible for multiple organ involvement and dysfunction. A systemic fetal inflammatory response is thought to be adaptive, but, on occasion, may become dysregulated whereby a fetal cytokine storm ensues and can lead to multiple organ dysfunction and even fetal death if delivery does not occur ("rescued by birth"). Thus, the onset of preterm labor in this context can be considered to have survival value. The evidence so far suggests that FIRS may compound the effects of immaturity and neonatal inflammation, thus increasing the risk of neonatal complications and long-term morbidity. Modulation of a dysregulated fetal inflammatory response by the administration of antimicrobial agents, anti-inflammatory agents, or cell-based therapy holds promise to reduce infant morbidity and mortality.

Serum levels of cytokines in infants treated with conbercept for retinopathy of prematurity

Intravitreal anti-vascular endothelial growth factor (VEGF) agents have revolutionized the treatment of retinopathy of prematurity (ROP); however, there are concerns regarding the potential systemic complications caused by those treatments. This study aimed to determine the serum concentrations of cytokines in infants with ROP and to evaluate the changes in serum VEGF concentrations after intravitreal conbercept (IVC). Sixty infants with ROP treated with IVC 0.25 mg were included. Blood samples were collected before treatment as well as 1 week and 4 weeks after treatment. Serum levels of 45 types of cytokines were measured by a multiplex bead assay. We observed that IVC 0.25 mg in ROP patients suppressed the circulating levels of VEGF-A and VEGF-D as of 1 week after injection, and these growth factor levels returned to baseline at 4 weeks. No significant differences were observed in the serum levels of the other cytokines between baseline and 1 or 4 weeks after IVC.

Effects of fish oil-containing lipid emulsions on retinopathy of prematurity in very low birth weight infants

BACKGROUND

The aim of the study was to assess the impact of different types of parenteral emulsions on retinopathy of prematurity (ROP) in very low birth weight (VLBW, birth body weight < 1500 g) infants by comparing fish oil-containing and soy-based parenteral emulsions.

METHODS

Data of preterm infants with body weights below 1500 gm at birth and receiving total parenteral nutrition (TPN) for a minimum of 7 days during the period between January 2009 and November 2017 were analyzed in this retrospective study. We compared clinical outcomes in two epochs using different lipid emulsions: epoch 1 (soybean-based lipid emulsions, January 2009-February 2014) versus epoch 2 (fish oil-containing lipid emulsions, January 2015-November 2017). The primary outcomes measured were the incidence of ROP and the number of ROP cases requiring bevacizumab therapy.

RESULTS

A total of 396 infants were enrolled in this study (203 in epoch 1 and 193 in epoch 2). A lower incidence of any stage ROP (24.1 vs. 11.4%, p < 0.001) and lower requirement of bevacizumab therapy (12.8 vs. 5.2%, p = 0.001) were observed in epoch 2. Gestational age, glutamic-pyruvic transaminase, total bilirubin, and alkaline phosphatase levels, and type of lipid emulsion in TPN were associated with higher ROP incidence. Multivariate logistic regression analysis revealed that parenteral nutrition in the form of lipid emulsions containing fish oil was associated with a lower risk of development of ROP [Odds Ratio: 0.178, 95% confidence interval (CI): 0.095-0.330, p < 0.001].

CONCLUSIONS

Compared with soybean-based lipid solutions, the use of fish oil-containing lipid solutions may be associated with a lower incidence of ROP and decreased need for bevacizumab treatment in preterm infants.

In-line filtration in very preterm neonates: a randomized controlled trial

In-line filtration is increasingly used in critically-ill infants but its benefits, by preventing micro-particle infusion in very preterm neonates, remain to be demonstrated. We conducted a randomized controlled trial among very preterm infants allocated to receive either in-line filtration of all the intra-venous lines or standard care without filters. The primary outcome was differences greater than 20% in the median changes in pro-inflammatory cytokine serum concentrations measured at day 3 and day 8 (+/-1) using a Luminex multianalytic profiling technique. Major neonatal complications were analyzed as secondary predefined outcomes. We randomized 146 infants, assigned to filter (n = 73) or control (n = 73) group. Difference over 20% in pro-inflammatory cytokine concentration between day 3 and day 8 was not found statistically different between the two groups, both in intent-to-treat (with imputation) and per protocol (without imputation) analyses. The incidences of most of neonatal complications were found to be similar. Hence, this trial did not evidence a beneficial effect of in-line filtration in very preterm infants on the inflammatory response syndrome and neonatal morbidities. These data should be interpreted according to local standards in infusion preparation and central line management.

Prenatal and postnatal inflammation-related risk factors for retinopathy of prematurity

OBJECTIVE

To evaluate the relationship between prenatal and postnatal inflammation-related risk factors and severe retinopathy of prematurity (ROP).

STUDY DESIGN

The study included infants born <30 weeks in California from 2007 to 2011. Multivariable log-binomial regression was used to assess the association between prenatal and postnatal inflammation-related exposures and severe ROP, defined as stage 3-5 or surgery for ROP.

RESULTS

Of 14,816 infants, 10.8% developed severe ROP. Though prenatal inflammation-related risk factors were initially associated with severe ROP, after accounting for the effect of these risk factors on gestational age at birth through mediation analysis, the association was non-significant (P = 0.6). Postnatal factors associated with severe ROP included prolonged oxygen exposure, sepsis, intraventricular hemorrhage, and necrotizing enterocolitis.

CONCLUSION

Postnatal inflammation-related factors were associated with severe ROP more strongly than prenatal factors. The association between prenatal inflammation-related factors and ROP was explained by earlier gestational age in infants exposed to prenatal inflammation.

Bone marrow mesenchymal stem cells modified by angiogenin-1 promotes tissue repair in mice with oxygen-induced retinopathy of prematurity by promoting retinal stem cell proliferation and differentiation

Retinopathy has become one of the major factors that lead to blindness worldwide. Although many clinical therapies are concerned about such disease, most of them focus on symptoms alleviation. In this study, we aim to investigate whether coculture retinal stem cells (RSCs) with bone marrow mesenchymal stem cells transfected with angiogenin-1 (Ang-1-BMSCs) affects the damaged retinal tissue of oxygen-induced retinopathy of prematurity (OIR-ROP) mice. After OIR-ROP mouse model establishment, Ang-1-BMSCs, RSCs, and OIR-ROP retinal tissues were cocultured in a a transwell chamber. RSCs proliferation and the expression of Ang-1, insulin-like growth factor-1 (IGF-1) in the supernatant of RSCs, as well as β-tubulin and protein kinase C (PKC) expression were evaluated. Finally, the repair of OIR-ROP mice retinal tissues was observed by injecting Ang-1-BMSCs + RSCs. In the OIR-ROP mouse model, RSCs cocultured with OIR-ROP retinal tissues could be induced to differentiate into cells expressing β-tubulin and PKC and promote the expression of Ang-1 and IGF-1. coculture of Ang-1-BMSCs further enhanced the proliferation and differentiation of RSCs by promoting the expression of Ang-1 and IGF-1. Coculture of RSCs + Ang-1-BMSCs induced differentiation of Ang-1-BMSCs through interaction among intercellular factors and restored the damaged retinal tissue of OIR-ROP mice. Collectively, our study provided evidence that coculture of Ang-1-BMSCs and RSCs could promote the proliferation and differentiation of RSCs and improve the treatment for the damaged retina tissue of OIR-ROP mice.

Interleukin-17: The Role for Pathological Angiogenesis in Ocular Neovascular Diseases

Ocular neovascular diseases are featured by abnormal angiogenesis in the eye, and they seriously threaten the human visual health. These diseases include proliferative diabetic retinopathy (PDR), age-related macular degeneration (AMD), retinopathy of prematurity (ROP), and retinal vein occlusion (RVO). In fact, ocular neovascular diseases represent the leading causes of vision impairment and blindness worldwide. Ocular neovascularization, the process of pathological vessel formation in eye, underlies ocular neovascular diseases. Cytokines have important regulatory roles in neovascularization through immunological networks. Interleukin (IL)-17, the signature cytokine produced by T helper 17 (Th17) cells, has proven to be involved in ocular neovascularization. However, roles of IL-17 in ocular neovascular diseases still remain controversial. This review provides an overview of the functional roles of IL-17 in ocular neovascular diseases from basic research to clinical evidence by focusing on PDR, AMD, ROP, and RVO. The possible roles of IL-17 in neovascularization are achieved through a regulatory network of cytoskeleton remodeling, vascular endothelial growth factor (VEGF), VEGF-related cytokines, and complement components. Current applications as well as potential therapies targeting IL-17 with genome editing systems are also outlined and discussed. Targeting IL-17 might be a promising therapeutic strategy against ocular neovascular diseases.

Aqueous cytokine levels associated with severity of type 1 retinopathy of prematurity and treatment response to ranibizumab

PURPOSE

To determine the aqueous humor levels of cytokines in eyes with type 1 retinopathy of prematurity (ROP) before primary intravitreal injection of ranibizumab (IVR).

METHODS

Forty-nine infants with type 1 ROP (56 eyes of 28 infants in the threshold ROP group and 42 eyes of 21 infants in the type 1 pre-threshold ROP group) received primary IVR and 49 aqueous humor samples were obtained preoperatively. Aqueous humor samples from 15 infants (15 eyes) undergoing congenital cataract surgery were used as controls. The concentrations of 27 cytokines were measured by a multiplex bead assay. Infants with persistent, recurrent, or progressive ROP after IVR were retreated.

RESULTS

The preoperative aqueous levels of 16 cytokines were significantly different among type 1 pre-threshold, threshold ROP, and control groups (P < 0.05). The concentrations of vascular endothelial growth factor (VEGF) (P < 0.001), interferon-γ (P < 0.001), interleukin (IL)-10 (P < 0.001), and IL-12 (P < 0.001) were the highest in the threshold ROP group, less in the type 1 pre-threshold ROP group, and the lowest in the control group. Retreatment was given to 55% of infants with ROP within a 48-week follow-up period after primary IVR. Higher VEGF (hazard ratio [HR] = 1.001, P = 0.001) and macrophage inflammatory protein-1β (HR = 1.085, P = 0.022) levels were independently correlated with ROP retreatment.

CONCLUSIONS

Higher aqueous levels of VEGF and inflammatory cytokines were associated with more severe type 1 ROP and ROP retreatment after primary IVR.

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.

Ureaplasma isolates stimulate pro-inflammatory CC chemokines and matrix metalloproteinase-9 in neonatal and adult monocytes

Being generally regarded as commensal bacteria, the pro-inflammatory capacity of Ureaplasma species has long been debated. Recently, we confirmed Ureaplasma–driven pro-inflammatory cytokine responses and a disturbance of cytokine equilibrium in primary human monocytes in vitro. The present study addressed the expression of CC chemokines and matrix metalloproteinase-9 (MMP-9) in purified term neonatal and adult monocytes stimulated with serovar 8 of Ureaplasma urealyticum (Uu) and serovar 3 of U. parvum (Up). Using qRT-PCR and multi-analyte immunoassay, we assessed mRNA and protein expression of the monocyte chemotactic proteins 1 and 3 (MCP-1/3), the macrophage inflammatory proteins 1α and 1β (MIP-1α/β) as well as MMP-9. For the most part, both isolates stimulated mRNA expression of all given chemokines and MMP-9 in cord blood and adult monocytes (p<0.05 and p<0.01). These results were paralleled by Uu and Up-induced secretion of MCP-1 protein in both cells (neonatal: p<0.01, adult: p<0.05 and p<0.01). Release of MCP-3, MIP-1α, MIP-1β and MMP-9 was enhanced upon exposure to Up (neonatal: p<0.05, p<0.01 and p<0.001, respectively; adult: p<0.05). Co-stimulation of LPS-primed monocytes with Up increased LPS-induced MCP-1 release in neonatal cells (p<0.05) and aggravated LPS-induced MMP-9 mRNA in both cell subsets (neonatal: p<0.05, adult: p<0.01). Our results document considerable expression of pro-inflammatory CC chemokines and MMP-9 in human monocytes in response to Ureaplasma isolates in vitro, adding to our previous data. Findings from co-stimulated cells indicate that Ureaplasma may modulate monocyte immune responses to a second stimulus.

Abnormal Complement Activation and Inflammation in the Pathogenesis of Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a neurovascular complication in preterm babies, leading to severe visual impairment, but the underlying mechanisms are yet unclear. The present study aimed at unraveling the molecular mechanisms underlying the pathogenesis of ROP. A comprehensive screening of candidate genes in preterms with ROP (n = 189) and no-ROP (n = 167) was undertaken to identify variants conferring disease susceptibility. Allele and genotype frequencies, linkage disequilibrium and haplotypes were analyzed to identify the ROP-associated variants. Variants in CFH (p = 2.94 × 10⁻⁷), CFB (p = 1.71 × 10⁻⁵), FBLN5 (p = 9.2 × 10⁻⁴), CETP (p = 2.99 × 10⁻⁵), and CXCR4 (p = 1.32 × 10⁻⁸) genes exhibited significant associations with ROP. Further, a quantitative assessment of 27 candidate proteins and cytokines in the vitreous and tear samples of babies with severe ROP (n = 30) and congenital cataract (n = 30) was undertaken by multiplex bead arrays and further validated by western blotting and zymography. Significant elevation and activation of MMP9 (p = 0.038), CFH (p = 2.24 × 10⁻⁵), C3 (p = 0.05), C4 (p = 0.001), IL-1ra (p = 0.0019), vascular endothelial growth factor (VEGF) (p = 0.0027), and G-CSF (p = 0.0099) proteins were observed in the vitreous of ROP babies suggesting an increased inflammation under hypoxic condition. Along with inflammatory markers, activated macrophage/microglia were also detected in the vitreous of ROP babies that secreted complement component C3, VEGF, IL-1ra, and MMP-9 under hypoxic stress in a cell culture model. Increased expression of the inflammatory markers like the IL-1ra (p = 0.014), MMP2 (p = 0.0085), and MMP-9 (p = 0.03) in the tears of babies at different stages of ROP further demonstrated their potential role in disease progression. Based on these findings, we conclude that increased complement activation in the retina/vitreous in turn activated microglia leading to increased inflammation. A quantitative assessment of inflammatory markers in tears could help in early prediction of ROP progression and facilitate effective management of the disease, thereby preventing visual impairment.

Ischemic Retinopathies: Oxidative Stress and Inflammation

Ischemic retinopathies (IRs), such as retinopathy of prematurity (ROP), diabetic retinopathy (DR), and (in many cases) age-related macular degeneration (AMD), are ocular disorders characterized by an initial phase of microvascular changes that results in ischemia, followed by a second phase of abnormal neovascularization that may culminate into retinal detachment and blindness. IRs are complex retinal conditions in which several factors play a key role during the development of the different pathological stages of the disease. Increasing evidence reveals that oxidative stress and inflammatory processes are important contributors to the pathogenesis of IRs. Despite the beneficial effects of the photocoagulation and anti-VEGF therapy during neovascularization phase, the need to identify novel targets to prevent initial phases of these ocular pathologies is still needed. In this review, we provide an update on the involvement of oxidative stress and inflammation in the progression of IRs and address some therapeutic interventions by using antioxidants and anti-inflammatory agents.

Diverse roles of macrophages in intraocular neovascular diseases: a review

Macrophages are involved in angiogenesis, and might also contribute to the pathogenesis of intraocular neovascular diseases. Recent studies indicated that macrophages exert different functions in the process of intraocular neovascularization, and the polarization of M1 and M2 phenotypes plays extremely essential roles in the diverse functions of macrophages. Moreover, a large number of cytokines released by macrophages not only participate in macrophage polarization, but also associate with retinal and choroidal neovascular diseases. Therefore, macrophage might be considered as a novel therapeutic target to the treatment of pathological neovascularization in the eye. This review mainly summarizes diverse roles of macrophages and discusses the possible mechanisms in retinal and choroidal neovascularization.

Retinopathy of prematurity: inflammation, choroidal degeneration, and novel promising therapeutic strategies

Retinopathy of prematurity (ROP) is an important cause of childhood blindness globally, and the incidence is rising. The disease is characterized by initial arrested retinal vascularization followed by neovascularization and ensuing retinal detachment causing permanent visual loss. Although neovascularization can be effectively treated via retinal laser ablation, it is unknown which children are at risk of entering this vision-threatening phase of the disease. Laser ablation may itself induce visual field deficits, and there is therefore a need to identify targets for novel and less destructive treatments of ROP. Inflammation is considered a key contributor to the pathogenesis of ROP. A large proportion of preterm infants with ROP will have residual visual loss linked to loss of photoreceptor (PR) and the integrity of the retinal pigment epithelium (RPE) in the macular region. Recent studies using animal models of ROP suggest that choroidal degeneration may be associated with a loss of integrity of the outer retina, a phenomenon so far largely undescribed in ROP pathogenesis. In this review, we highlight inflammatory and neuron-derived factors related to ROP progression, as well, potential targets for new treatment strategies. We also introduce choroidal degeneration as a significant cause of residual visual loss following ROP. We propose that ROP should no longer be considered an inner retinal vasculopathy only, but also a disease of choroidal degeneration affecting both retinal pigment epithelium and photoreceptor integrity.

Serum eotaxin-1 is increased in extremely-low-birth-weight infants with bronchopulmonary dysplasia or death

BACKGROUND

Early systemic inflammation in extremely-low-birth-weight (ELBW) infants is associated with an increased risk of bronchopulmonary dysplasia (BPD). Our objective was to identify circulating biomarkers and develop prediction models for BPD/death soon after birth.

METHODS

Blood samples from postnatal day 1 were analyzed for C-reactive protein (CRP) by enzyme-linked immunosorbent assay and for 39 cytokines/chemokines by a multiplex assay in 152 ELBW infants. The primary outcome was physiologic BPD or death by 36 wk. CRP, cytokines, and clinical variables available at ≤24 h were used for forward stepwise regression and Classification and Regression Tree (CART) analysis to identify predictors of BPD/death.

RESULTS

Overall, 24% developed BPD and 35% died or developed BPD. Regression analysis identified birth weight and eotaxin (CCL11) as the two most significant variables. CART identified FiO2 at 24 h (11% BPD/death if FiO2 ≤28%, 49% if >28%) and eotaxin in infants with FiO2 > 28% (29% BPD/death if eotaxin was ≤84 pg/ml; 65% if >84) as variables most associated with outcome.

CONCLUSION

Eotaxin measured on the day of birth is useful for identifying ELBW infants at risk of BPD/death. Further investigation is required to determine if eotaxin is involved in lung injury and pathogenesis of BPD.