Bilirubin induces microglial NLRP3 inflammasome activation in vitro and in vivo.

Despite current advancements in neonatal care, hyperbilirubinemia resulting in bilirubin-induced neurological dysfunction (BIND) continues to be one of the major reasons of mortality or lifelong disability. Although the exact mechanisms underlying brain injury upon bilirubin exposure remains unelucidated, inflammation is considered to be one of the major contributors to BIND. This study investigates the role of the NLRP3 inflammasome in bilirubin-induced injury using in vitro and in vivo models. We successfully demonstrated that the upregulation of NLRP3 expression is significantly associated with the release of active caspase-1 and IL-1ß in N9 microglial cells exposed to bilirubin. Functional in vitro experiments with NLRP3 siRNA confirms that bilirubin-induced inflammasome activation and cell death are mediated by the NLRP3 inflammasome. Following injection of bilirubin into the cisterna magna of a neonatal mouse, activation of the NLRP3 inflammasome and microglia were determined by double staining with Iba1-NLRP3 and Iba1-Caspase-1. Upon injection of bilirubin into the cisterna magna, neuronal loss was significantly higher in the wild-type mouse compared to Nlrp3-/- and Caspase-1-/- strains. Collectively, these data indicate that NLRP3 inflammasome has a crucial role in microglial activation and bilirubin-induced neuronal damage.

Current factors affecting the risk of omphalitis in newborns: A prospective case-control study.

AIM: We aimed to determine the current factors affecting the development of omphalitis in our region. MATERIALS AND METHODS: This prospective case-control study included term and late preterm newborns admitted to the newborn outpatient clinic or paediatric emergency service between 2014 and 2015. One hundred newborns with omphalitis and age-matched 100 newborns as a control group were included. The perinatal, postnatal, and sociocultural characteristics of newborns were evaluated and the factors that could influence the development of omphalitis were determined. RESULTS: Younger maternal age and primiparity, lower maternal education, and lower maternal hand washing habits were the significant risk factors of omphalitis development. Using non-cotton clothes were the most important risk factor amongst all factors as it increases the omphalitis risk up to 13 times. The frequency of omphalitis was significantly higher in warm months when microorganisms were able to colonise and reproduce compared with the colder months. CONCLUSION: Results suggested that community-based interventions promoting the improvement of neonatal care should emphasise simple and low-cost interventions such as hand washing habit of mothers, caring for the umbilical cord, and using cotton clothes for babies. This study also confirms the safety of dry cord care at the time of birth and afterwards. However, broadscale multicentric studies are needed to protect against omphalitis.

Zonisamide attenuates hyperoxia-induced apoptosis in the developing rat brain.

Oxygen therapy used in the treatment of perinatal hypoxia induces neurodegeneration in babies with immature antioxidant mechanisms. Zonisamide is a new antiepileptic drug used in childhood intractable seizures. Many studies demonstrated its neuroprotective effects. There is no study evaluating its effect on hyperoxic brain injury. The aim of this study was to investigate the neuroprotective effect of zonisamide on hyperoxia-induced neonatal brain injury. A total of 21 Wistar rat pups were used. The animals were divided into three groups: control group, hyperoxia group, and zonisamide-treated group. The zonisamide-treated group received an intraperitoneal injection of zonisamide. Zonisamide significantly preserved the number of neurons in CA1 and dentate gyrus parts of hippocampus, prefrontal, and parietal cortex. Zonisamide treatment also decreased the number of apoptotic neurons in all examined parts of hippocampus, prefrontal, and parietal cortex. We suggest that zonisamide treatment may be used as a neuroprotective agent in hyperoxic brain injury.

Thrombocytopenia in neonates: causes and outcomes.

Thrombocytopenia is one of the most common hematological abnormalities found in neonates. The causes, treatment modalities, and outcomes of neonatal thrombocytopenia have to be evaluated for providing better care and follow-up. In this study, our aim was to assess the prevalence, causes, treatment modalities, and outcomes of thrombocytopenia in neonates. A retrospective analysis was conducted on the medical records of all neonates hospitalized at our hospital between January 2007 and December 2011 and those with thrombocytopenia were included in the study. Of the 3,515 neonates, 134 (3.8%) had thrombocytopenia. Ninety-seven of them (72%) were preterm. In the patients admitted to neonatal intensive care unit, the prevalence of thrombocytopenia was found as 12%, whereas it was found as 1.2% in neonatal service. The highest prevalence was detected in the year 2008 by 5.3%, and the lowest prevalence was detected in the year 2011 by 2.4%. Sepsis was the most common etiologic factor between years 2007 and 2009. Intrauterine growth restriction, metabolic disorders, drugs, and asphyxia were more common causes in the recent years. Severe thrombocytopenia was found in 26% of neonates and 11 % of thrombocytopenic neonates had major hemorrhage. Intracranial hemorrhage ratio was 5.9% and all of these patients were preterm. Thrombocytopenia improved in 92.5% of patients and persisted in 3% of patients. Death occurred in 4.5% of neonates. This study shows that the causes of neonatal thrombocytopenia may show variations with respect to time and the prevalence, complications, and risks of thrombocytopenia may be lowered by eliminating preventable factors.

Breast milk jaundice: effect of bacteria present in breast milk and infant feces.

OBJECTIVE: Breast milk is an important source of bacteria in establishing the infantile intestinal microbiota that appear to influence the enterohepatic circulation of bilirubin. The aim of the present study was to evaluate the effect of breast milk's microbiological content on the development of breast milk jaundice (BMJ). METHODS: A total number of 60 mother-infant pairs enrolled to the study. Two groups were defined: BMJ group (n=30), full-term otherwise healthy newborns who were considered BMJ; control group (n=30), full-term healthy newborns without jaundice. All newborns in the study were exclusively breast-fed. The breast milk samples and the feces of infants were evaluated for content of selected bacterial populations (Bifidobacterium, Lactobacillus, Clostridium, Staphylococcus, and Streptococcus species) with real-time polymerase chain reaction. RESULTS: Bifidobacterium bifidum content in the breast milk and B adolescentis, B bifidum, and B longum content in the fecal samples were higher in the control group than in the BMJ group. The milk and fecal concentrations of B bifidum were significantly correlated. The concentrations of breast milk B bifidum and fecal B bifidum, B adolescentis, and B longum were found to be negatively correlated with bilirubin levels. CONCLUSIONS: Our results suggest that Bifidobacterium species in breast milk may protect against BMJ.

Cord blood ischemia-modified albumin: is it associated with abnormal Doppler findings in complicated pregnancies and predictive of perinatal asphyxia?

AIM: To evaluate the significance of the cord blood ischemia-modified albumin (IMA) level as a diagnostic marker for perinatal asphyxia and to determine the associations of IMA levels with the complexity of pregnancy and abnormal Doppler findings, regardless of perinatal asphyxia. METHODS: This prospective study included 169 newborns, sixteen of whom had perinatal asphyxia and 33 who were from complicated pregnancies. Doppler measurements were obtained from the uterine, umbilical and middle cerebral arteries, and the cerebro/placental ratio (C/P). IMA was measured by means of commercially available ELISA kits and was expressed as picomoles per milliliter. RESULTS: Ischemia-modified albumin levels were significantly higher in neonates of complicated pregnancies as compared to uncomplicated pregnancies (P < 0.0001). They were higher in newborns with perinatal asphyxia as compared to healthy controls (P = 0.015). The C/P ratio-pulsatility index (PI) showed a significant difference between normal and complicated pregnancies without perinatal asphyxia (P < 0.0001). IMA levels were significantly increased in cases with abnormal C/P ratio-PI. CONCLUSIONS: Elevated cord blood IMA levels may be accepted as a useful marker in perinatal asphyxia. Abnormal Doppler examinations are associated with elevated IMA levels in complicated pregnancies.

A zebrafish model for studying the mechanisms of newborn hyperbilirubinemia and bilirubin-induced neurological damage.

Unresolved neonatal hyperbilirubinemia may lead to the accumulation of excess bilirubin in the body, and bilirubin in neural tissues may induce toxicity. Bilirubin-induced neurological damage (BIND) can result in acute or chronic bilirubin encephalopathy, causing temporary or lasting neurological dysfunction or severe damage resulting in infant death. Although serum bilirubin levels are used as an indication of severity, known and unknown individual differences affect the severity of the symptoms. The mechanisms of BIND are not yet fully understood. Here, a zebrafish newborn hyperbilirubinemia model is developed and characterized. Direct exposure to excess bilirubin induced dose- and time-dependent toxicity linked to the accumulation of bilirubin in the body and brain. Introduced bilirubin was processed by the liver, which increased the tolerance of larvae. BIND in larvae was demonstrated by morphometric measurements, histopathological analyses and functional tests. The larvae that survived hyperbilirubinemia displayed mild or severe morphologies associated with defects in eye movements, body posture and swimming problems. Interestingly, a plethora of mild to severe clinical symptoms were reproduced in the zebrafish model.

Impact of Maternal Ketogenic Diet on NLRP3 Inflammasome Response in the Offspring Brain.

The effects of maternal diet on the neuroimmune responses of the offspring remain to be elucidated. We investigated the impact of maternal ketogenic diet (KD) on the NLRP3 inflammasome response in the offspring's brain. C57BL/6 female mice were randomly allocated into standard diet (SD) and ketogenic diet (KD) groups for 30 days. After mating, the presence of sperm in the vaginal smear was considered day 0 of pregnancy, and female mice continued their respective diets during pregnancy and the lactation period. Following birth, pups were further allocated into two groups and given either LPS or intraperitoneal saline on postnatal (PN) days 4, 5 and 6; they were sacrificed on PN11 or PN21. Neuronal densities were significantly lower globally in the KD group when compared to the SD group at PN11. Neuronal density in the prefrontal cortex (PFC) and dentate gyrus (DG) regions were also significantly lower in the KD group when compared to the SD group at PN21. Following administration of LPS, the decrease in the neuronal count was more prominent in the SD group when compared to the KD group in the PFC and DG regions at PN11 and PN21. NLRP3 and IL-1ß were higher in the KD group than in the SD group at PN21 in the PFC, CA1 and DG regions, and were significantly lower in the DG region of the KD group especially when compared to the SD group following LPS. Results of our study reveal that maternal KD negatively affects the offspring's brain in the mouse model. The effects of KD exhibited regional variations. On the other hand, in the presence of KD exposure, NLRP3 expression after LPS injection was lower in the DG and CA1 areas but not in the PFC when compared to SD group. Further experimental and clinical studies are warranted to elucidate the molecular mechanisms underlying the impact of antenatal KD exposure and regional discrepancies on the developing brain.

Genetic basis of apnoea of prematurity and caffeine treatment response: role of adenosine receptor polymorphisms: genetic basis of apnoea of prematurity.

AIM: Caffeine treatment reduces the frequency of apnoea of prematurity (AOP) and eliminates the need for mechanical ventilation by acting as a nonspecific inhibitor of adenosine A1 and adenosine 2A receptors. Patients with AOP have demonstrated variant responses to caffeine therapy. We proposed to investigate the role of A1 and 2A polymorphisms in the development of AOP and individual differences in caffeine response. Secondly, we aimed to determine whether these polymorphisms have any effect on bronchopulmonary dysplasia (BPD) development. METHODS: Cord blood samples were collected from infants born with gestational ages between 24 and 34 weeks. Two groups were defined: patients without apnoea (n = 60) and patients with apnoea (n = 55). Patients with apnoea were divided into two subgroups: a caffeine-responsive group (n = 30) and an unresponsive group (n = 25). Six single-nucleotide polymorphisms were chosen for genotyping. RESULTS: Patients with apnoea over 28 weeks of gestational age who responded to the caffeine treatment were found to carry the rs16851030 C/C genotype rather than the C/T or T/T genotype. Logistic regression analysis showed a significant correlation between rs35320474-C/T and T/T genotypes and apnoea and BPD development. CONCLUSION: Our results indicate a role for adenosine receptor gene polymorphisms in susceptibility to AOP and BPD and in interindividual variability to caffeine response.

In vitro effects of H2O2 on neural stem cell differentiation.

The development of the CNS is a complex and well-regulated process, where stem cells differentiate into committed cells depending on the stimuli from the microenvironment. Alterations of oxygen levels were stated to be significant in terms of brain development and neurogenesis during embryonic development, as well as the adult neurogenesis. As a product of oxygen processing, hydrogen peroxide (H2O2) has been established as a key regulator, acting as a secondary messenger, of signal transduction and cellular biological functions. H2O2 is involved in survival, proliferation, and differentiation of neural stem cells into committed cells of the CNS. Effects of different concentrations of exogenous H2O2 on neuronal differentiation and the molecular pathways involved are yet to be clearly understood. Here, we investigated the concentration-dependent effects of H2O2 on differentiation of neural stem cells using CGR8 embryonic mouse stem cell line. We have demonstrated that treated doses of H2O2 suppress neural differentiation; additionally, our study suggests that relatively high doses of exogenous H2O2 suppress the differentiation process of neural stem cells through AKT and p38 pathways.

Severe iron overload and hyporegenerative anemia in a case with rhesus hemolytic disease: therapeutic approach to rare complications.

A 33 weeks' gestation, a baby with rhesus hemolytic disease (RHD), who had received intrauterine transfusions twice, developed cholestatic hepatic disease and late hyporegenerative anemia. Her serum ferritin and bilirubin levels increased to 8842 ng/ml and 17.9 mg/dl, respectively. Liver biopsy showed cholestasis and severe iron overload. Treatment with recombinant erythropoietin (rHuEPO) decreased the transfusion need, and intravenous deferoxamine resulted in a marked decreased in serum ferritin levels and normalization of liver function. In patients who have undergone intrauterine transfusions due to RHD, hyperferritinemia and late hyporegenerative anemia should be kept in mind. Chelation therapy in cases with symptomatic hyperferritinemia and rHuEPO treatment in cases with severe hyporegenerative anemia should be considered.

Oxygen exposure in early life activates NLRP3 inflammasome in mouse brain.

Despite widely known detrimental effects on the developing brain, supplemental oxygen is still irreplaceable in the management of newborn infants with respiratory distress. Identifying downstream mechanisms underlying oxygen toxicity is a key step for development of new neuroprotective strategies. Main purpose of this study is to investigate whether NLRP3 inflammasome activation has a role in the pathogenesis of hyperoxia-induced preterm brain injury. C57BL6 pups were randomly divided into either a hyperoxia group (exposed to 90 % oxygen from birth until postnatal day 7) or control group (maintained in room air; 21 % O2). At postnatal day 7, all animals were sacrificed. Immunohistochemical examination revealed that hyperoxic exposure for seven days resulted in a global increase in NLRP3 and IL-1ß immunopositive cells in neonatal mouse brain (p ≤ 0.001). There was a significant rise in Caspase-1 positive cell count in prefrontal and parietal area in the hyperoxia group when compared with controls (p ≤ 0.001). Western blot analysis of brain tissues showed elevated NLRP3, IL-1ß and Caspase-1 protein levels in the hyperoxia group when compared with controls (p ≤ 0.001). To the best of our knowledge, this is the first study that investigates an association between hyperoxia and establishment of NLRP3 inflammasome in preterm brain.

Epigenetic Programming Through Breast Milk and Its Impact on Milk-Siblings Mating.

BACKGROUND: The epigenetic effects of transmission of certain regulatory molecules, such as miRNAs, through maternal milk on future generations, are still unknown and have not been fully understood yet. We hypothesized that breastfeeding regularly by adoptive-mother may cause transmission of miRNAs as epigenetic regulating factors to the infant, and the marriage of milk-siblings may cause various pathologies in the future generations. RESULTS: A cross-fostering model using a/a and A vy /a mice had been established. F2 milk-sibling and F2 control groups were obtained from mating of milk-siblings or unrelated mice. Randomized selected animals in the both F2 groups were sacrificed for miRNA expression studies and the remainings were followed for phenotypic changes (coat color, obesity, hyperglycemia, liver pathology, and life span). The lifespan in the F2 milk-sibling group was shorter than the control group (387 vs 590 days, p = 0.011) and they were more obese during the aging period. Histopathological examination of liver tissues revealed abnormal findings in F2 milk-sibling group. In order to understand the epigenetic mechanisms leading to these phenotypic changes, we analyzed miRNA expression differences between offspring of milk-sibling and control matings and focused on the signaling pathways regulating lifespan and metabolism. Bioinformatic analysis demonstrated that differentially expressed miRNAs were associated with pathways regulating metabolism, survival, and cancer development such as the PI3K-Akt, ErbB, mTOR, and MAPK, insulin signaling pathways. We further analyzed the expression patterns of miR-186-5p, miR-141-3p, miR-345-5p, and miR-34c-5p and their candidate target genes Mapk8, Gsk3b, and Ppargc1a in ovarian and liver tissues. CONCLUSION: Our findings support for the first time that the factors modifying the epigenetic mechanisms may be transmitted by breast milk and these epigenetic interactions may be transferred transgenerationally. Results also suggested hereditary epigenetic effects of cross-fostering on future generations and the impact of mother-infant dyad on epigenetic programming.

Breast milk jaundice correlates with high levels of epidermal growth factor.

Maternal milk plays an important role in breast milk jaundice (BMJ) development and is the major source of epidermal growth factor (EGF) for neonates. The aim of this study was to investigate whether there is a relationship between EGF levels in the infant serum and in the milk of nursing mothers and BMJ. Two groups were defined: study group (n = 30), newborns who were followed up for BMJ without any identifiable pathologic cause; control group, healthy newborns whose serum total bilirubin levels were <10 mg/dL. Milk and infant plasma samples were collected between the third and the fourth postpartum week. EGF concentrations in all of the samples were determined by using ELISA. The infants with BMJ had higher concentrations of EGF in the serum and in the breast milk compared with that of the infants without BMJ. The milk concentrations of EGF were significantly correlated with neonatal bilirubin and blood EGF concentrations. The degree of BMJ was associated with the increased levels of milk borne EGF. Although the exact mechanisms of the hyperbilirubinemic action of EGF are not completely known, the inhibition of gastric motility, increased absorption, and activation of bilirubin transport have been suggested as possible mechanisms.

WITHDRAWN: TRANSIENT TACHYPNEA OF THE NEWBORN: A PREDICTIVE FACTOR FOR PROLONGED TACHYPNEA.

Ahead of Print article withdrawn by publisher.

The relationship between glucagon-like peptide 2 and feeding intolerance in preterm infants.

Glucagon-like peptide 2 (GLP-2) is a hormone produced primarily in the distal intestine, stimulated by enteral nutrients, and playing diverse roles in the intestinal adaptation and growth. We aimed to investigate whether GLP-2 may play a role in the development of feeding intolerance which is a common problem in preterm newborns resulting from the intestinal immaturity. The study included 20 term and 28 preterm neonates. Of preterm babies, 13 showed feeding intolerance fulfilling at least one of the following criteria: abdominal distension, increased gastric residual volume and presence of bile in the gastric aspirate. The plasma GLP-2 levels measured prior to enteral feeding (fasting level) and at 60 min after the beginning of the feeding (post-pradial level) were correlated with of clinical parameters. There was no statistical difference between GLP-2 levels of overall preterm babies and those of term newborns. However, preterm neonates with feeding intolerance showed significantly lower levels of GLP-2 and increased duration to achieve full enteral feeding and hospitalization. It is suggested that GLP-2 plays a significant role in the regulation of feeding in newborns and that preterm babies with low levels of GLP-2 carry a risk for development of feeding intolerance. It may, therefore, be of relevance to investigate the therapeutic and prophylactic effects of GLP-2 administration in the preterm babies.

Effects of maternal folic acid supplementation on airway remodeling and allergic airway disease development.

Objective: Maternal folic acid supplementation has been recommended prior to and during the first trimester of pregnancy to reduce the risk of infant neural tube defects. However, an uncertain relationship between folic acid supplementation during pregnancy and development of childhood asthma exists. Recent data show a methyl donor-rich diet could increase the risk of developing allergic airway disease through DNA methylation and aberrant gene transcription. This study evaluated the effect of folic acid supplementation during pregnancy on airway remodeling and allergic airway disease vulnerability in a mouse asthma model. Methods: BALB/c mice were divided into four groups according to gestational folic acid supplementation and postnatal ovalbumin (OVA) exposure: Group 1 (whole pregnancy folic acid supplementation + OVA-exposed group), Group 2 (first gestational week folic acid supplementation + OVA-exposed group), Group 3 (no folic acid supplementation + OVA-exposed group), and Group 4 (control group). Offspring were sacrificed on day 45 for immunohistological and ultrastructural tests. Results: In OVA challenged groups, folic acid supplementation led to a thicker epithelial and subepithelial smooth muscle layer than in the unsupplemented group. Moreover, folic acid supplementation during whole pregnancy (Group 1) was associated with a thicker epithelial and subepithelial smooth muscle layer than folic acid supplementation during the first week of pregnancy (Group 2), suggesting a duration-response relationship. Electron microscopic imaging revealed that structural changes including the loss of epithelial integrity, thickening of basement membrane, and subepithelial fibrosis were more prominent in the folic acid supplementation groups. Conclusions: This study suggested that maternal folic acid supplementation during pregnancy affects airway remodeling and increases the allergic responses induced by ovalbumin challenge in offspring. In addition, the effect size increased as the duration and cumulative dose increased.

Is European Medicines Agency (EMA) sepsis criteria accurate for neonatal sepsis diagnosis or do we need new criteria?

BACKGROUND: Currently, there is a lack of clear definition for neonatal sepsis. The Pediatric Committee of the European Medicines Agency (EMA) developed consensus criteria to ensure a standardization for neonatal sepsis definition. However, there is no evidence supporting the accuracy of the EMA sepsis criteria in neonatal sepsis diagnosis. The main objective of this study was to evaluate the diagnostic accuracy of EMA sepsis criteria for proven neonatal sepsis. METHODS: A multicenter prospective cohort study was conducted from October 2015 to November 2018. Infants with a gestational age over 34th weeks, diagnosed with clinical sepsis and received antibiotics according to the EMA criteria or experienced neonatologists' opinion were included. Blood culture or multiplex real time-PCR or 16S-rRNA positive infants were accepted as "proven sepsis". The predictive performance of EMA criteria for proven sepsis was evaluated by sensitivity, specificity, accuracy, and area under the curve measures of receiver operator characteristic curves. Data-mining methods were used for further analysis. RESULTS: Among the 245 included infants, the EMA criteria were positive in 97 infants (39.6%), while proven sepsis was diagnosed in 113 infants (46.1%). The sensitivity, specificity, and accuracy of the EMA criteria for proven sepsis were 44.2% (95%CI: 34.9-53.9), 64.4% (95%CI: 55.6-72.5), 55.1% (95%CI: 46.6-59.4) respectively. None of the clinical and laboratory parameters had sufficient performance individually in terms of sensitivity, specificity and accuracy measures. The diagnostic performance was similar when different clinical findings were added to the EMA sepsis criteria or assessment of the score was interpreted in different ways. CONCLUSIONS: Results highlighted that clinician opinion and standard laboratory tests are limited in the neonatal sepsis diagnosis. The EMA criteria also did not efficiently meet the diagnostic accuracy measures for neonatal sepsis. A predictive sepsis definition and rapid bedside point-of care tests are urgently needed.

Effects of activated protein C on neonatal hypoxic ischemic brain injury.

Perinatal hypoxia-ischemia remains the single most important cause of brain injury in the newborn, leading to death or lifelong sequelae. White matter injuries in newborn infants have long-term effects on physical, visual, motor, sensory, cognitive and social development in human infants. There is no known cure for neonatal hypoxic ischemic encephalopathy (NHIE). Activated protein C has potent anticoagulant activity due to its ability to inactivate factor Va and VIIIa. APC is the first effective biological therapy approved for the treatment of severe sepsis. Although APC is well defined as a physiological anticoagulant, emerging data suggest that it also has cytoprotective, anti-inflammatory and antiapoptotic properties. APC has been shown to provide neuroprotection in ischemic brain and spinal cord injury. Here, we propose that APC, which modulates many of these processes, may represent a promising therapeutic agent for NHIE. Seven days old Wistar Albino rat pups have been used in the study (n=42). Experimental groups in the study were: sham-operated group, APC treated group, and vehicle treated group. In hypoxia-ischemia groups, the left common carotid artery was ligated permanently on the seventh postnatal day. Two hours after the procedure, hypoxia (92% nitrogen and 8% oxygen) was applied for 2.5 h. APC were injected (intraperitoneally; i.p.) as a single dose immediately after the hypoxia period. Brain nitrite levels, neuronal cell death, and apoptosis were evaluated in both hemispheres 72 h after the hypoxic-ischemic insult. Histopathological evaluation demonstrated that APC significantly diminished the number of "apoptotic cells" in the hippocampal CA1, CA2, CA3 and gyrus dentatus regions in both hemispheres. APC treatment significantly reduced "apoptotic cell death" in both hemispheres, when compared with vehicle treated group. APC significantly preserved the number of neurons CA1, CA3 regions of the hippocampus, when compared with vehicle treated group. Our results showed that hypoxic-ischemic injury caused a significant increase in NO production. The APC-treated animals were reduced brain nitrite levels in carotid ligated hemispheres. To our knowledge, this is the first study that demonstrates a protective effect of the APC against hypoxia-ischemia in the developing brain.

Effect of erythropoietin on oxygen-induced brain injury in the newborn rat.

The developing nervous system is sensitive to supraphysiological oxygen concentrations. Recent studies showed that exposure to hyperoxia in infant rats leads to extensive apoptotic degeneration in the cortex and white matter of the developing brain. A wide variety of experimental studies have shown that erythropoietin exerts a remarkable neuroprotection in both cell cultures and in animal models of nervous system disorders. In the present study, we investigated the effect of erythropoietin against hyperoxia-induced neurodegeneration in the developing brain. Eighteen Wistar rat pups were divided into three groups: control group, hyperoxia+saline-treated group and hyperoxia+erythropoietin-treated group. Hyperoxia groups were exposed to 80% oxygen (n=12) in a plexiglas chamber in which the oxygen concentration was monitored twice daily from birth until postnatal day 5. Hyperoxia exposure was 24h/day for 5 days. The hyperoxia+erythropoietin group received an intraperitoneal injection of recombinant human erythropoietin at a dose of 1000U/(kgday). At postnatal day 5, all animals were sacrificed. Neuronal cell death and apoptosis were evaluated. Histopathological examination showed that erythropoietin significantly diminished apoptosis in the CA1 region and dentate gyrus of hippocampus and parietal cortex in hyperoxia+erythropoietin-treated group. Regarding the safety profile of erythropoietin in premature and mature infants, this agent may be potentially beneficial in preventing hyperoxic brain injury.