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.

Maternal omega-3 fatty acid supplementation protects against lipopolysaccharide-induced white matter injury in the neonatal rat brain.

OBJECTIVES: Periventricular leukomalacia (PVL) is the predominant form of brain injury in premature infants, and no specific treatment currently exists for this condition. We have evaluated whether maternal omega-3 fatty acid (ω3 FA) treatment reduces endotoxin-induced PVL in the developing rat brain. METHODS: Wistar rats with dated pregnancies were fed a standard diet or a diet enriched in ω3 FA (70% docosahexaenoic acid + 30% eicosapentaenoic acid mixture) during gestation. Intraperitoneal injection of lipopolysaccharide (LPS) was administered consecutively on the 18th and 19th embryonic days to establish the endotoxin-induced PVL rat model. The animals were divided into four groups: (i) control, (ii) PVL, (iii) PVL+low-dose ω3 FA and (iv) PVL+high-dose ω3 FA. At day P7, apoptosis and hypomyelination in periventricular white matter were evaluated by immunohistochemical assessments. RESULTS: High-dose maternal ω3 FA treatment reduced brain weight loss. Maternal ω3 FA treatment given either in low or high doses greatly decreased caspase-3 immunoreactivity and increased myelin basic protein immunoreactivity, indicating a decrease in apoptosis and hypomyelination. CONCLUSION: Considering that no specific treatment is available for PVL, maternal ω3 FA supplementation may provide a nutritional strategy to limit periventricular white matter damage caused by infections during pregnancy.

Effect of leptin treatment on neonatal hypoxic-ischemic brain injury.

OBJECTIVE: The aim of this study was to investigate the possible neuroprotective and ameliorating effects of leptin treatment in hypoxic-ischemic injury induced neuronal cell death. METHODS: Experimental groups in the study were: sham-operated group, leptin treated hypoxia-ischemia group, and vehicle treated hypoxia-ischemia group. In hypoxia-ischemia group, 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. Leptin treatment was injected (intraperitoneally; i.p.) as a single dose immediately after the hypoxia period. Neuronal cell death, neuronal density, and leptin levels were evaluated in both hemispheres 72 h after the hypoxic-ischemic insult. RESULTS: Compared with the hypoxic-ischemia group, the mean leptin levels were higher in the brains of the sham group for both hemispheres. The leptin treatment significantly diminished the number of 'apoptotic cells' in the hippocampal CA1, CA2, CA3, and gyrus dentatus regions in both hemispheres. Leptin treatment significantly preserved the number of neurons in both hemispheres, when compared with the vehicle treated group. CONCLUSION: We conclude that leptin treatment improves neuronal density and decreases apoptosis in the newborn rat with hypoxic-ischemic brain injury.

Is gastric aspiration needed for newborn management in delivery room?

AIM: Gastric aspiration is still applied in many centres during delivery room management of the newborn without any supporting evidence. We aimed to determine whether gastric aspiration affects vital signs, oxygenation, nutrition and short-term prognosis of the newborn. METHOD: A total of 310 eligible healthy term newborns, identified from a total of 1300 live births, were randomly allocated to receive either gastric aspiration or standard care. During the first 20min, SpO(2), heart rate, cyanosis and retraction scores were recorded once in a min; and blood pressure, respiration rate and neuroadaptive capacity were recorded once in every 5min. Information about nutrition and vomiting behaviours of the babies were taken from the mothers of the neonates on the postnatal 1st day at bedside and by a telephone call on the 7th day. RESULTS: No difference was determined between the groups in terms of 1st to 5thmin Apgar scores, attainment duration of SpO(2) to 85%, 92% and 95%, mean heart rate and respiration rate. Retraction frequency and mean systolic blood pressure of the 5th-min values were found to be significantly higher in the gastric aspiration group. There was no difference between the groups regarding breastfeeding starting time and vomiting frequency. CONCLUSION: No positive effect of gastric aspiration in delivery room management of the newborn was observed. Conversely, the negative effects of gastric aspiration in neonates were observed with respect to physiological parameters. Our data suggest that gastric aspiration is not useful and may even be harmful in delivery room management of the healthy term newborns.

Protective effects of methylxanthines on hypoxia-induced apoptotic neurodegeneration and long-term cognitive functions in the developing rat brain.

Aminophylline is widely used in the management of premature apnea. The methylxanthines aminophylline, theophylline and caffeine are nonspecific inhibitors of adenosine receptors. There are no proven effects of methylxanthines on acute brain injury and long-term cognitive functions. This study is aimed at investigating the effects of methylxanthines on brain injury and cognitive functions. Newborn rats were allocated to form four groups, which contained at least 21 pups: two groups were exposed to room air and two groups were exposed to intermittent hypoxia. Intraperitoneal aminophylline was administered to treatment groups during postnatal day 1 through postnatal day 7. All rats were sacrificed on postnatal day 8 via intraperitoneal pentobarbital and the effects of the administered drug on brain injury and adenosine receptor expression were determined. Cognitive functions of rats were evaluated via water maze test. Histopathological evaluation demonstrated that aminophylline significantly diminished the number of 'apoptotic cells' in the hippocampal CA1, CA2, CA3 and gyrus dentatus regions in the brain. Aminophylline treatment immediately after hypoxic insult significantly improved long-term neurobehavioral achievements. In conclusion, aminophylline administration immediately after neonatal hypoxic insult provides benefit over a prolonged period in the developing rat brain.

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.

Clarithromycin, montelukast, and pentoxifylline combination treatment ameliorates experimental neonatal hyperoxic lung injury.

OBJECTIVE: We aimed to assess the efficiency of clarithromycin, montelukast, and pentoxifylline treatments, alone and in combination, in reducing hyperoxic lung injury at the histopathologic level. METHODS: The experiment was carried out with 47 newborn rat pups divided into six groups during postnatal days 3 to 13. The rats belonging to group 1 were designated as the control group and kept in room air without exposure to hyperoxia. Group 2 (clarithromycin), group 3 (montelukast), group 4 (pentoxifylline), group 5 (clarithromycin + montelukast + pentoxifylline combination), and group 6 (placebo) were kept in plexiglass chamber and exposed to hyperoxia (88-92%) throughout the experiment. Alveolar surface area percentage, fibrosis, and smooth muscle actin expression were assessed in the lungs, which were resected by thoracotomy on postnatal day 14. RESULTS: Drug treatments, when used separately, were not detected to be superior to placebo with regard to mean alveolar surface area, fibrosis, and smooth muscle actin expression. Combination treatment resulted in significantly higher mean lung area percentages and lower actin scores with respect to the placebo treatment group (64.0% vs. 50.2%, p=0.002; 0 (0-1) vs. 7 (2-12), p=0.005, respectively). CONCLUSIONS: It was determined that clarithromycin, montelukast, and pentoxifylline combination treatment is superior to placebo treatment in the newborn rat hyperoxic lung injury model. The present study indicates that combination therapy might be successful in bronchopulmonary dysplasia, which has complex pathophysiologic processes and lacks established efficient treatment strategies.

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.

Erythropoietin attenuates lipopolysaccharide-induced white matter injury in the neonatal rat brain.

Periventricular leukomalacia (PVL), a common neonatal brain white matter (WM) lesion, is frequently associated with cerebral palsy. Growing evidence has indicated that in addition to ischemia/reperfusion injury, cytokine-induced brain injury associated with maternal or fetal infection may also play an important role in the pathogenesis of PVL. Recent studies have shown that administration of lipopolysaccharide (LPS) to pregnant rats causes enhanced expression of the cytokines, i.e., IL-1 beta, TNF-alpha, and IL-6, in fetal brains. In recent years, it has been shown that erythropoietin (EPO) has a critical role in the development, maintenance, protection and repair of the nervous system. In the present study we investigated the effect of EPO on LPS-induced WM injury in Sprague-Dawley rats. LPS (500 microg/kg) suspension in pyrogen-free saline was administered intraperitoneally to pregnant rats at 18 and 19 days of gestation. The control group was treated with pyrogen-free saline. They were given 5,000 U/kg recombinant human EPO. Seven-day-old Sprague-Dawley rat pups were divided into four groups: control group, LPS-treated group, prenatal maternal EPO-treated group (5,000 U/kg, intraperitoneally given to pregnant rats at 18 and 19 days of gestation), and postnatal EPO-treated group (5,000 U/kg, intraperitoneally given to 1-day-old rat pups). Cytokine induction in the postnatal 7-day-old (P7) rat brain after maternal administration of LPS was determined by the ELISA method. The proinflammatory cytokine levels (IL-1 beta, TNF-alpha, and IL-6) in P7 rat pup brains were significantly increased in the LPS-treated group as compared with the control group. Prenatal maternal EPO treatment significantly reduced the concentration of TNF-alpha and IL-6 in the newborn rat brain following LPS injection. The concentration of IL-1 beta was decreased in the intrauterine EPO treatment group. Postnatal EPO treatment significantly decreased only the IL-6 concentration in the newborn rat brain following LPS injection. The concentration of cytokines, IL-1 beta and TNF-alpha, was reduced in the postnatal EPO treatment group. We demonstrated here that LPS administration in pregnant rats at gestational day 18 and 19 induced WM injury in P7 progeny characterized by apoptosis. Prenatal maternal and postnatal EPO treatment significantly reduced the number of apoptotic cells in the periventricular WM. Using immunohistochemistry techniques, we investigated the effects of maternal administration of LPS on myelin basic protein (MBP) staining, as a marker of myelination in the periventricular area in the neonatal rat brain. MBP staining was significantly less and weaker in the brains of the LPS-treated group as compared with the prenatal maternal EPO-treated group. However, the postnatal EPO treatment did not prevent LPS-stimulated loss of MBP-positive staining. In conclusion, especially prenatal maternal EPO treatment attenuates LPS-induced injury by reducing the expression of inflammatory cytokines and sparing MBP in the neonatal rat brain. While the postnatal EPO treatment prevented LPS-induced brain injury this effect was partial. To our knowledge, this is the first study that demonstrates a protective effect of EPO on LPS-induced WM injury in the developing brain. Regarding the wide use of EPO in premature newborns, this agent maybe potentially beneficial in treating LPS-induced brain injury in the perinatal period.

Activated protein C reduces endotoxin-induced white matter injury in the developing rat brain.

Periventricular leukomalacia (PVL), the dominant form of brain injury in premature infants, is characterized by white matter injury (WMI) and is associated with cerebral palsy. The pathogenesis of PVL is complex and likely involves ischemia/reperfusion, free radical formation, excitotoxicity, impaired regulation of cerebral blood flow, a procoagulant state, and inflammatory mechanisms associated with maternal and/or fetal infection. Using an established animal model of human PVL, we investigated whether activated protein C (APC), an anti-coagulant factor with anti-inflammatory, anti-apoptotic, anti-oxidant, and cytoprotective activities, could reduce endotoxin-induced WMI in the developing rat brain. Intraperitoneal injections of lipopolysaccharide (LPS) (0.5 mg/kg body weight) were given at embryonic days 18 (E18) and 19 (E19) to pregnant Sprague-Dawley rats; control rats were injected with sterile saline. A single intravenous injection of recombinant human (rh) APC (0.2 mg /kg body weight) was given to pregnant rats following the second LPS dose on embryonic day 19 (E19). Reduced cell death in white matter and hypomyelination were shown on TUNEL and myelin basic protein (MBP) staining, respectively, on late postnatal days (P7) in APC-treated groups. There were significantly fewer TUNEL+nuclei in the periventricular WM in the APC+LPS group than in the untreated LPS group. Compared to the APC+LPS and control group, MBP expression was weak in the LPS group on P7, indicating endotoxin-induced hypomyelination in the developing rat brain. APC attenuated the LPS-induced protein expression of inflammatory cytokines, tumor necrosis factor-alpha, and interleukin-6, as evaluated by ELISA in neonatal rat brains. A single intraperitoneal injection of rhAPC (0.2 mg/kg body weight) to neonatal rats on P1 also had similar protective and anti-inflammatory effects against maternally administered LPS. Collectively, these data support the hypothesis that APC may provide protection against an endotoxin-evoked inflammatory response and WMI in the developing rat brain. Moreover, our results suggest that the possible use of APC in treatment of preterm infants and pregnant women with maternal or placental infection may minimize the risk of PVL and cerebral palsy.

Neuroprotective effect of the peptides ADNF-9 and NAP on hypoxic-ischemic brain injury in neonatal rats.

Perinatal asphyxia is an important cause of neonatal mortality and subsequent serious sequelae such as motor and cognitive deficits and seizures. Recent studies have demonstrated that short peptides derived from activity-dependent neurotrophic factor (ADNF) and activity-dependent neuroprotective protein (ADNP) are neuroprotective at femtomolar concentrations. However, the effect of these peptides on the hypoxic-ischemic brain injury model is unknown. The aim of this study is to investigate the effects of the peptides ADNF-9 and NAP on neurodegeneration and cerebral nitric oxide (NO) production in a neonatal rat model of hypoxic-ischemic brain injury. Seven-day-old Wistar Albino rat pups have been used in the study (n=42). Experimental groups in the study were: sham-operated group, ADNF-9-treated hypoxia-ischemia group, NAP-treated hypoxia-ischemia group, ADNF-9+NAP-treated hypoxia-ischemia group, and vehicle-treated group. In hypoxia-ischemia groups, 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. ADNF-9, NAP, and ADNF-9+NAP 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 (carotid ligated or nonligated) 72 h after the hypoxic-ischemic insult. Histopathological evaluation demonstrated that ADNF-9 and NAP significantly diminished number of "apoptotic cells" in the hippocampal CA1, CA2, CA3, and gyrus dentatus regions in both hemispheres (ligated and nonligated). When compared with vehicle-treated group, combination treatment with ADNF-9+NAP did not significantly reduce "apoptotic cell death" in any of the hemispheres. ADNF-9 and NAP, when administered separately, significantly preserved the number of neurons CA1, CA2, CA3, and dentate gyrus regions of the hippocampus, when compared with vehicle-treated group. The density of the CA1, CA2, and dentate gyrus neurons was significantly higher when combination therapy with ADNF-9+NAP was used in the carotid ligated hemispheres. In the nonligated hemispheres, combination therapy preserved the number of neurons only in the CA1 and dentate gyrus regions. Brain nitrite levels were evaluated by Griess reagent and showed that hypoxic-ischemic injury caused a significant increase in NO production. Brain nitrite levels in ADNF-9+NAP-treated animals were not different in carotid ligated or nonligated hemispheres. The peptides ADNF-9 and NAP significantly decreased NO overproduction in the hypoxic-ischemic hemisphere, whereas no significant change appeared in hypoxia alone and also in the sham-operated group. These results suggest the beneficial neuroprotective effect of ADNF-9 and NAP in this model of neonatal hypoxic-ischemic brain injury. To our knowledge, this is the first study that demonstrates a protective effect of these peptides against hypoxia-ischemia in the developing brain.