Chorioamnionitis disrupts erythropoietin and melatonin homeostasis through the placental-fetal-brain axis during critical developmental periods.

Introduction: Novel therapeutics are emerging to mitigate damage from perinatal brain injury (PBI). Few newborns with PBI suffer from a singular etiology. Most experience cumulative insults from prenatal inflammation, genetic and epigenetic vulnerability, toxins (opioids, other drug exposures, environmental exposure), hypoxia-ischemia, and postnatal stressors such as sepsis and seizures. Accordingly, tailoring of emerging therapeutic regimens with endogenous repair or neuro-immunomodulatory agents for individuals requires a more precise understanding of ligand, receptor-, and non-receptor-mediated regulation of essential developmental hormones. Given the recent clinical focus on neurorepair for PBI, we hypothesized that there would be injury-induced changes in erythropoietin (EPO), erythropoietin receptor (EPOR), melatonin receptor (MLTR), NAD-dependent deacetylase sirtuin-1 (SIRT1) signaling, and hypoxia inducible factors (HIF1α, HIF2α). Specifically, we predicted that EPO, EPOR, MLTR1, SIRT1, HIF1α and HIF2α alterations after chorioamnionitis (CHORIO) would reflect relative changes observed in human preterm infants. Similarly, we expected unique developmental regulation after injury that would reveal potential clues to mechanisms and timing of inflammatory and oxidative injury after CHORIO that could inform future therapeutic development to treat PBI. Methods: To induce CHORIO, a laparotomy was performed on embryonic day 18 (E18) in rats with transient uterine artery occlusion plus intra-amniotic injection of lipopolysaccharide (LPS). Placentae and fetal brains were collected at 24 h. Brains were also collected on postnatal day 2 (P2), P7, and P21. EPO, EPOR, MLTR1, SIRT1, HIF1α and HIF2α levels were quantified using a clinical electrochemiluminescent biomarker platform, qPCR, and/or RNAscope. MLT levels were quantified with liquid chromatography mass spectrometry. Results: Examination of EPO, EPOR, and MLTR1 at 24 h showed that while placental levels of EPO and MLTR1 mRNA were decreased acutely after CHORIO, cerebral levels of EPO, EPOR and MLTR1 mRNA were increased compared to control. Notably, CHORIO brains at P2 were SIRT1 mRNA deficient with increased HIF1α and HIF2α despite normalized levels of EPO, EPOR and MLTR1, and in the presence of elevated serum EPO levels. Uniquely, brain levels of EPO, EPOR and MLTR1 shifted at P7 and P21, with prominent CHORIO-induced changes in mRNA expression. Reductions at P21 were concomitant with increased serum EPO levels in CHORIO rats compared to controls and variable MLT levels. Discussion: These data reveal that commensurate with robust inflammation through the maternal placental-fetal axis, CHORIO impacts EPO, MLT, SIRT1, and HIF signal transduction defined by dynamic changes in EPO, EPOR, MLTR1, SIRT1, HIF1α and HIF2α mRNA, and EPO protein. Notably, ligand-receptor mismatch, tissue compartment differential regulation, and non-receptor-mediated signaling highlight the importance, complexity and nuance of neural and immune cell development and provide essential clues to mechanisms of injury in PBI. As the placenta, immune cells, and neural cells share many common, developmentally regulated signal transduction pathways, further studies are needed to clarify the perinatal dynamics of EPO and MLT signaling and to capitalize on therapies that target endogenous neurorepair mechanisms.

Decreased Cerebral Oxygenation in Premature Infants with Progressive Posthemorrhagic Ventricular Dilatation May Help with Timing of Intervention.

OBJECTIVE: The objective of this study was to determine the degree of progressive posthemorrhagic ventricular dilatation (PHVD) that is associated with a significant decrease in regional cerebral oxygen saturation (rScO2) in premature infants at risk for periventricular-intraventricular hemorrhage (PIVH). STUDY DESIGN: Cranial ultrasound (US) and near-infrared spectroscopy (NIRS) measurements of rScO2 were performed on inborn infants with birth weights less than 1,250 g on admission and at 1, 4, and 8 weeks of age. Infants with severe PIVH were studied weekly. A 1-hour average of rScO2 was compared with the frontal-occipital horn ratio (FOHR) measured the same day. Generalized linear models were used to analyze the relationship between FOHR and rScO2, by severity of PIVH, and adjusted for gestational age. Cut-off points of 0.55 for FOHR and 45% for rScO2 were used to calculate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The study cohort included 63 infants with normal US, 15 with grade-1 or -2 PIVH (mild group), and 21 with grade-3 or -4 PIVH (severe group). Increases in FOHR in the severe group were associated with decreases in rScO2 at 1 week (p = 0.036), 4 weeks (p = 0.013), and 8 weeks of life (p = 0.001) compared with the normal and mild groups. Infants with FOHR greater than 0.55 were 92% more likely to have rScO2 less than 45% when compared with infants with FOHR less than 0.55 (OR = 0.08, 95% CI: [0.04, 0.13], p < 0.001). CONCLUSION: Progressive PHVD (FOHR > 0.55) is a strong predictor of compromised cerebral oxygenation. A combination of rScO2 and FOHR measurements may aid in identifying infants with PHVD that would benefit from early intervention. KEY POINTS: · Earlier intervention in PHVD may improve outcomes.. · PHVD is diagnosed with US measurements of ventricular size.. · FOHR > 0.55 is associated with decreased cerebral perfusion..

Delayed Hemolytic Transfusion Reaction in a Patient With Sickle Cell Disease and the Role of the Classical Complement Pathway: A Case Report.

A 14-year-old female patient with sickle cell disease developed a severe delayed hemolytic transfusion reaction (DHTR) leading to multiple transfusions and intensive care management. To better understand the extent to which the classical complement pathway was contributing to her DHTR, we utilized the complement hemolysis using human erythrocytes (CHUHE) assay and the classical complement pathway inhibitor, PIC1. Residual discarded de-identified plasma and erythrocytes from the patient obtained from routine phlebotomy was acquired. These reagents were used in the CHUHE assay in the presence of increasing concentrations of PIC1. Complement-mediated hemolysis of the patient's erythrocytes occurred in her plasma and complement permissive buffer. Increasing concentrations of PIC1 dose-dependently inhibited hemolysis to levels found for the negative control - complement inhibitor buffer. Complement-mediated hemolysis was demonstrated by the CHUHE assay for this patient with sickle cell disease and severe DHTR. PIC1 inhibition of hemolysis suggested that the classical complement pathway was contributing to her DHTR.