Mete Akisu

Platelet-activating factor is an important mediator in hypoxic ischemic brain injury in the newborn rat: Flunarizine and Ginkgo biloba extract reduce PAF concentration in the brain

Hypoxic-ischemic encephalopathy is still a very important cause of neonatal mortality and morbidity. Recently, platelet-activating factor (PAF) has been accused of being responsible for the neuronal damage in hypoxic-ischemic brain. We investigated tissue PAF concentrations in hypoxic-ischemic brain injury in immature rats. Endogenous PAF concentration in brain tissue showed a marked increase in hypoxic-ischemic pups (85.6 ± 15.5 pg/mg protein) when compared to that of control (9.05 ± 3.1 pg/mg protein). In addition, we examined the effects of flunarizine, a selective calcium channel blocker, and Ginkgo biloba extract (EGb 761) on endogenous PAF concentration in hypoxic-ischemic brain injury. Endogenous PAF concentrations in both flunarizine-pretreated (16.6 ± 4.8 pg/mg protein) and EGb 761-pretreated (33.5 ± 8.9 pg/mg protein) pups were significantly lower than the untreated group. These results indicate that PAF is an important mediator in immature rat model of cerebral hypoxic-ischemic injury. The suppressor effect of flunarizine and EGb 761 on PAF production may open new insight into the treatment of hypoxic-ischemic brain injury.

Selective head cooling with hypothermia suppresses the generation of platelet-activating factor in cerebrospinal fluid of newborn infants with perinatal asphyxia

Hypoxic-ischemic encephalopathy (HIE) remains one of the most important neurologic complications in the newborn. Several experimental and clinical studies have shown that hypothermia is the most effective means known for protecting the brain against hypoxic-ischemic brain damage. Furthermore, recent data have suggested that platelet-activating factor (PAF) could play a pathophysiologically important role in the progression of hypoxic-ischemic brain injury. The aim of the present study was to investigate the role of head cooling combined with minimal hypothermia in short-term outcome of infants with perinatal asphyxia. In addition, we have examined the effect of head cooling combined with minimal hypothermia on PAF concentrations in cerebrospinal fluid (CSF) after hypoxic-ischemic brain injury. The group of asphyxiated infants (Group 1) consisted of 21 full-term (gestational age >37 weeks). These infants were randomized and divided into either a standard therapy group (Group 1a; n=10) or cooling group (Group 1b; n=11). Head cooling combined with minimal hypothermia (rectal temperature 36.5-36 degrees C) was started as soon as practicable after birth. The infants were cooled for 72h and then were rewarmed at 0.5 degrees C/h. The control group (Group 2) consisted of seven full-term infants and none of these infants showed any sign of asphyxia. To measure PAF concentration in CSF, CSF with lumbar puncture was collected into tubes immediately before the cooling (1-3h after birth) and again after 36h. We had no evidence of severe adverse events related to hypothermia. In Group 1a, two infants died after 72h of life; however, all newborn infants in Group 1b survived. Convulsion required treatment in three infants of standard therapy group (1a); none of the infants in Group 1b had clinical seizure activity. Abnormal EEG patterns were found in four infants of Group 1a; no EEG abnormalities were noted in Group 1b (P<0.05). On admission (before cooling), PAF concentration in CSF of asphyxiated infants was found to be significantly higher when compared with that of control (P<0.001). Mean PAF concentration before initiation of the study was similar in the two asphyxiated groups (Group 1a vs. 1b) (P>0.05). Obtained PAF level in CSF after 36h, showed a profound decline in cooling group of infants compared to Group 1a infants (P<0.01). In conclusion, the present study suggests that cerebral cooling with minimal hypothermia started soon after birth has no severe adverse effects during 72-h cooling period and that short-term outcome of infants are encouraging. Our results also support the hypothesis PAF an important mediator in hypoxic-ischemic brain injury and demonstrate that head cooling combined with minimal hypothermia reduces the normal increase in PAF following hypoxic-ischemic brain injury in full-term infants.

Protective Effect of Dietary Supplementation with L-Arginine and L-Carnitine on Hypoxia/Reoxygenation-Induced Necrotizing Enterocolitis in Young Mice

Oxygen-derived free radicals are important components of gastrointestinal injury in necrotizing enterocolitis (NEC). In the present investigation, we examined the protective actions of L-arginine, a nitric oxide synthase substrate, and L-carnitine against hypoxia-reoxygenation (H/R) induced NEC in young mice. Young mice were divided into four groups: group 1 mice were subjected to H/R only; group 2 H/R mice were supplemented with L-arginine in the drinking water (2 g/l) for 7 days; group 3 H/R mice were given L-carnitine solution in water (50 mg/kg p.o.) for 7 days, and group 4 mice served as controls.Hypoxia was induced by placing the mice in a 100% CO2 chamber for 5 min. After hypoxia, the mice were reoxygenated for 10 min with 100% oxygen. We examined the intestinal lesions by light microscopy and measured the intestinal generation of thiobarbituric acid reactive substances (TBARS) and the activities of superoxide dismutase and catalase in the H/R-induced model of NEC. In both L-arginine and L-carnitine groups, the NEC-induced intestinal tissue damage was greatly attenuated, with necrosis limited partially to the mucosa. The tissue TBARS level was significantly higher in group 1 than in any of the other groups (p < 0.001). However, those treated with L-arginine and L-carnitine had TBARS levels similar to those in the control animals. An increased tissue concentration of nitrate, a stable metabolite of nitric oxide, was found in the L-arginine-supplemented group as compared with the control group (p < 0.05). Both superoxide dismutase and catalase activities in the intestine were similar in H/R groups when compared with the intestine of control animals. The present study suggests that oxygen-derived free radicals are involved in the pathogenesis of H/R-induced NEC. This study also shows that dietary supplementation with L-arginine and L-carnitine ameliorates the histological evidence of H/R-induced intestinal injury and significantly decreases lipid peroxidation in H/R-induced bowel injury. Based on these findings, the beneficial effects of L-arginine and L-carnitine in this model may be mediated via mechanisms preventing free radical damage.

Successful caspofungin treatment of multidrug resistant Candida parapsilosis septicaemia in an extremely low birth weight neonate.

Candida septicaemia with multidrug resistance is an uncommon event in preterm neonates. We present an extremely low birth weight infant (gestational age of 27 weeks, birth weight of 980 g) who developed congenital Candida parapsilosis septicaemia. Because the fungus was resistant both to amphotericin B and fluconazole, caspofungin was chosen for therapy. The fungus was successfully eradicated without any clinical or laboratory adverse effects.

Insulin-Like Growth Factor Attenuates Apoptosis and Mucosal Damage in Hypoxia/Reoxygenation-Induced Intestinal Injury

Objective: Necrotizing enterocolitis (NEC) is a potentially lethal disease among premature infants. The aim of the present study was to investigate whether hypoxia-reoxygenation (H/R)-induced intestinal injury was due to increased apoptosis of the intestinal mucosa in young mice and whether pre-treatment of the animals with recombinant human insulin-like growth factor-I (IGF-I), a known anti-apoptotic factor, could protect the intestinal cells from H/R-induced apoptosis or intestinal injury. Study Design: Young mice were divided into three groups: group 1 mice (H/R) were hypoxia-reoxygenation; group 2 mice (H/R + IGF-I) were treated with recombinant human IGF-I by intraperitoneal injection (1 µg/g b.w. once daily) for 7 days, and group 3 mice served as control. Hypoxia was induced by placing young mice in a Plexiglas chamber consisting of 10% oxygen for 60 min. After hypoxia, the young mice were reoxygenated for 10 min with 100% oxygen. Intestinal generation of substances reactive to thiobarbituric acid (TBARS) and active caspase-3 were measured in H/R-induced intestinal injury. Results: Increased numbers of apoptotic cells (apoptotic index) across the villi in young mice subjected to H/R were observed with the TUNEL reaction whereas few apoptotic cells existed in the control animals. In addition, H/R-induced intestinal damage in the H/R + IGF-I group was greatly attenuated, with necrosis limited partially to the mucosa. Tissue-active caspase-3 levels in the H/R group were found to be significantly higher when compared with that of the H/R + IGF-I group of mice and control. However, TBARS concentrations in the intestine were similar in H/R groups when compared to the intestine of control animals. Conclusion: The present study suggests that both necrosis and apoptosis, via mechanisms occurring due to oxygen-derived free radicals and activation of caspase-3, play a role in the pathogenesis of H/R-induced bowel injury. We also show that IGF-I protect intestinal mucosa from necrosis and apoptosis from intestinal H/R injury.

Histological Chorioamnionitis: Effects on Premature Delivery and Neonatal Prognosis

BACKGROUND Chorioamnionitis is closely related to premature birth and has negative effects on neonatal morbidity and mortality. METHODS In this prospective study, 43 mothers who delivered earlier than 35 gestational weeks and their 57 infants were evaluated clinically and with laboratory findings. Placentas and umbilical cords were investigated histopathologically for chorioamnionitis and funisitis. RESULTS The overall frequency of clinical and histological chorioamnionitis (HCA) was 8.3% and 23.2%, respectively. The frequency of HCA was 47.3% and 83.3% in mothers delivered <32 weeks and <30 weeks, respectively. Maternal demographic and clinical findings and also leukocyte and C-reactive protein values were not indicative of HCA. Infants of mothers with HCA had significantly lower Apgar scores together with higher SNAP-PE-II and CRIB scores. These infants had increased mechanical ventilator and surfactant requirements, higher incidences of patent ductus arteriosus, early sepsis, and bronchopulmonary dysplasia, and higher mortality rates. The effect of HCA on neonatal morbidity and mortality was more prominent than the effect of low birthweight and lower gestational age. CONCLUSION Chorioamnionitis not only causes premature deliveries, but is also associated with neonatal complications and increased mortality. Clinical findings and infectious markers in mother or infant do not predict the diagnosis of histological chorioamnionitis. Therefore, placental histopathology may have a role in predicting neonatal outcome in premature deliveries, especially those below 30 weeks.

Plasma concentrations of granulocyte-macrophage colony-stimulating factor and interleukin-6 in septic and healthy preterms.

Abstract Plasma granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) concentrations were determined in 21 preterm infants with sepsis and nine healthy preterm neonates of the same postnatal age at sampling. Plasma GM-CSF levels were elevated at diagnosis in the septic preterms as compared to the healthy preterms (P = 0.01), but did not differ significantly on recovery. IL-6 levels were also elevated markedly at diagnosis (P = 0.0003), but decreased to normal on recovery as compared to the healthy preterm infants. GM-CSF levels were more prominent in septic preterms with neutropenia than those of non-neutropenic infants (P = 0.03). Conclusion Preterm infants can produce high levels of granulocyte-macrophage colony-stimulating factor and interleukin-6 in response to bacterial sepsis.

Effect of dietary n-3 fatty acids on hypoxia-induced necrotizing enterocolitis in young mice. n-3 fatty acids alter platelet-activating factor and leukotriene B4 production in the intestine.

Necrotizing entercolitis (NEC) is an important neonatal disease with a high mortality rate. Inflammatory mediators, such as mainly platelet-activating factor (PAF), leukotrienes (LT) and tumor necrosis factor play an important role in the genesis of NEC. Diets in Ω–3 (n–3) fatty acids appear to have an antiinflammatory effect, which is thought to be due to decreased active prostaglandins and leukotrienes production after incorporation of these fatty acids into cell membrane phospholipids. We investigated the protective effect of fish oil (source of n–3 fatty acids) on hypoxia-induced model of NEC. Young mice were divided into three groups; group 1 mice were fed standard chow (n–3 fatty acids-free), group 2 was fed a chow supplemented by 10% fish oil for 4 weeks. Group 3 mice served as control. We examined the intestinal lesions by light microscopy and measured intestinal tissue PAF and LB4 levels in hypoxia-induced model of NEC. Significantly increased intestinal PAF and LTB4 levels were found in group 1 mice when compared to group 2 and group 3 mice. The histopathology of the intestinal lesions in group 1 animals was characteristic of ischemic injury. In the n–3 fatty acids-supplemented animals these lesions were milder. The present study shows that endogenously released PAF and LTB4 play an important role in mediating hypoxia-induced intestinal necrosis. The present study also suggests that dietary supplementation with n–3 fatty acids suppress intestinal PAF and LTB4 generation in hypoxia-induced bowel necrosis. The intestinal protective effect of n–3 fatty acids in an experimental model of NEC may open new insight into the treatment and preventation of NEC in neonates.

Mannose-binding lectin gene polymorphism and early neonatal outcome in preterm infants.

Background: Mannose-binding lectin (MBL) as a component of innate immunity plays an important role in preterm infants in whom adaptive immunity is not sufficiently developed. Polymorphisms in immunoregulatory genes influence the response to infection and subsequent inflammation. Infection and inflammation have been implicated in the mechanisms responsible for many of the diseases in the preterm newborns. Objectives: The aim of the study was to investigate the relationship between MBL gene polymorphism and early neonatal outcome in preterm infants. Methods: Codon 54 and 57 polymorphisms in MBL2 gene were genotyped in 99 preterm infants admitted to the Neonatal Intensive Care Unit at Ege University Children’s Hospital. Results: Overall frequencies of sepsis and early-onset sepsis were higher in the group of infants with MBL polymorphism when compared to infants with wild-type MBL genotype (p = 0.008, 0.009, respectively). Maximum Tollner sepsis score in the first 3 days of life was higher for the infants with variant MBL genotype (p = 0.0278). More infants in the variant MBL group had significant patent ductus arteriosus when compared to infants with wild-type MBL (27.8 vs. 9.5% respectively, p = 0.037). Conclusion: MBL gene polymorphism was associated with increased frequency of clinical sepsis particularly with early neonatal sepsis and also with higher Tollner sepsis scores and increased frequency of patent ductus arteriosus in infants. Overall mortality and incidence of culture proven sepsis, respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia and necrotizing enterocolitis were not found to be related to MBL genotype.

SINGLE-CENTER EXPERIENCE: Use of Recombinant Factor VIIa for Acute Life-Threatening Bleeding in Children without Congenital Hemorrhagic Disorder

Coagulopathy is an important cause of mortality in critically ill children. Traditional therapies to correct coagulopathy lead to great time delays and cause fluid overload in patients. The authors report the effectiveness and safety of the activated recombinant factor VII (rFVIIa) administration in a series of 13 nonhemophiliac children with acute, life-threatening bleeding. In this retrospective study, the records of the patients who were not diagnosed with congenital hemorrhagic disorder and were administered rFVIIa due to any other reason in Ege University Faculty of Medicine, Department of Pediatrics, between February 2002 and February 2007 were reviewed retrospectively. Thirteen nonhemophiliac patients with acute life-threatening bleeding and ages ranging from 2 days to 15 years received rFVIIa over a 5-year period. Three patients were diagnosed with hemaphagocytic lymphohistiocytosis, 4 with prematurity, sepsis, and disseminated intravascular coagulation (DIC), 5 with sepsis, multiple organ dysfunction syndrome, and DIC, and 1 with acute liver failure. Severe bleeding resulted from pulmonary (n = 3), lower gastrointestinal system (n = 2), esophagus varices (n = 1), pulmonary and gastrointestinal system (n = 4), pulmonary, gastrointestinal system, and intracranial hemorrhage (n = 1), and gastrointestinal system and intracranial hemorrhage (n = 2). Median frequency of rFVIIa administration was 3 per patient (range 2–15) and median dose of rFVIIa was 90 μg/kg, ranging from 60 to 135 μg/kg each administration. All of the patients were given fresh frozen plasma and if necessary platelet transfusion (n = 10) or fibrinogen concentrate (n = 3) before administration of rFVIIa. In 6 patients, lack of success to control bleeding by conventional methods was the only cause to start rFVIIa. In 7 patients, the need for volume restriction was also a significant contributing factor in deciding to start rFVIIa. Median PT was 32.9 s (range: 19–65) before rFVIIa administration and it was decreased to 11.6 s (range: 10.7–12.8), 2–3 h after rFVIIa infusion. Bleeding was stopped completely in 10 patients at least for 24 h and decreased in 3 patients 30–45 min after rFVIIa administration. Two patients had thrombotic complications attributed to rFVIIa administration. No other complication was observed in the other patients. In this retrospective study, rFVIIa was found to be effective at controlling severe hemorrhagic symptoms of different etiologies in children without congenital hemorrhagic disorder. In addition to the rapid control of bleeding, administration of this agent improved fluid balance and led to a reduction in blood product requirements in critically ill children. However, survival was still poor (23%), and 2/13 (15.4%) patients developed venous and arterial thrombosis within 3 h of treatment. The authors emphasize that in acquired, acute life-threatening bleeding, simultaneous administration of rFVIIa with conventional treatment may contribute to patient survival. However, the risk of thromboembolism should be considered before this treatment is given.