A.W. Danilo Gavilanes

Chorioamnionitis induced by intraamniotic lipopolysaccharide resulted in an interval-dependent increase in central nervous system injury in the fetal sheep

OBJECTIVE We quantified the impact of chorioamnionitis on both the white and gray matter structures of the preterm ovine central nervous system (CNS). STUDY DESIGN The CNS was studied at 125 days of gestation, either 2 or 14 days after the intraamniotic administration of 10 mg of lipopolysaccharide (LPS) (Escherichia coli) or saline. Apoptotic cells and cell types were analyzed in the brain, cerebellum, and spinal cord using flow cytometry. RESULTS Apoptosis and microglial activation increased in all regions with prolonged exposure to LPS-induced chorioamnionitis. Astrocytes were increased in the brain and cerebellum of LPS-exposed fetuses but not in the spinal cord. Mature oligodendrocytes decreased in the cerebral and cerebellar white matter, the cerebral cortex, caudate putamen, and hippocampus 14 days after LPS. Neurons in the cerebral cortex, hippocampus, and substantia nigra were reduced 14 days after LPS. CONCLUSION Fetal inflammation globally but differentially affected the CNS depending on the maturational stage of the brain region.

Effects of hypothermia and gender on survival and behavior after perinatal asphyxia in rats

Previous studies in rats have demonstrated that perinatal asphyxia (PA) produces long-term morphological alterations, particularly affecting hippocampus. neostriatum, and cerebral cortex. These changes were prevented by applying hypothermia during the asphyctic insult. Because these cerebral areas are involved in cognitive and motor functions, the aim of the present study was to determine whether periods of PA during normothermia or hypothermia produces long-term behavioral impairments in rats of both sexes. The cognitive and motor functions were studied using the spatial Morris water maze (MWM) task at 1.5 months, and the open field at 5 months, respectively. The present study revealed that female rats had a higher survival rate than males after PA in normothermic conditions (p < 0.014). and that hypothermia drastically prolonged the time of survival in both sexes (p < 0.001). There were no differences in learning and memory functions between groups or male and female rats when tested with MWM. Rats subjected to hypothermia treatment did not show differences in the MWM compared to controls. A lower locomotor activity in the open field test was only observed in male rats that suffered 15 and 20 min of PA in normothermia (p < 0.05). Hypothermia treatment prevented this hypoactivity. PA in females, even if severe, did not affect the motor activity. The data of both behavioral tests showed differences between sexes, i.e., the female rats learned the MWM task slower, and were more active in the open field. This work lends further support for the hypothesis that hypothermia can prevent mortality as well as long-term sequelae induced by PA.

Fetal asphyctic preconditioning protects against perinatal asphyxia-induced behavioral consequences in adulthood

Perinatal asphyxia is one of the major causes of neuronal injury and impaired development in infants. We recently have shown that a brief episode of experimental fetal asphyxia (FA) can provoke an endogenous neuroprotection against subsequent severe perinatal asphyxia (SPA). The long-lasting functional consequences of FA preconditioning are not clear yet. The aim of the study was to determine if FA preconditioning can provide a long-lasting behavioral protection against SPA. FA was induced, as a preconditioning stimulus, by clamping the uterine vasculature for 30 min on E17. At birth, SPA was induced by placing the uterine horns in a water bath for 19 min. At 6 months of age, functional outcome was assessed using different behavioral tests: the open field for locomotor activity, the elevated zero maze for anxiety-related behavior, the forced swim test for depression-related behavior and the object recognition task for cognition. Data showed that FA preconditioning improved postnatal mortality after SPA. At the age of 6 months, the total distance moved in the open field and elevated zero maze was significantly less in the SPA group compared to the control groups. In addition, cognitive performance in the object recognition task was impaired in the SPA offspring compared to the control groups. Most importantly, FA preconditioning was able to preserve both locomotor activity and cognition function. In conclusion, FA preconditioning induces a long-lasting, functional protection against SPA. Therefore, this model seems to offer good opportunities for the identification and characterization of the underlying mechanisms of preconditioning.

Chorioamnionitis induced hepatic inflammation and disturbed lipid metabolism in fetal sheep.

Chorioamnionitis frequently induces a fetal inflammatory response syndrome (FIRS), characterized by an elevation of proinflammatory mediators and systemic inflammation. Although there is increasing evidence that inflammation and lipid metabolism influence each other, the effects of chorioamnionitis-induced FIRS on fetal lipid homeostasis are currently not known. Accordingly, we hypothesize that chorioamnionitis induces an inflammatory response in the fetal liver, consequently leading to metabolic disturbances. Chorioamnionitis was induced by intra-amniotic injection of 10 mg endotoxin (control) for 2 d or 2 wk before delivery. Saline injections were given to controls. The effect of chorioamnionitis on hepatic inflammation and metabolic parameters was analyzed in ovine fetuses at the GA of 125 d (normal GA = 150 d). We found that 2 d after the endotoxin injections, inflammatory markers were significantly higher compared with controls. In addition, lipid and glucose metabolism were disturbed in response to endotoxin. Moreover, the antioxidant state capacity was reduced, and hepatic damage was apparent. Two weeks after the endotoxin injections, the fetal livers were still inflamed and had higher glucose concentrations in the blood. In addition, the levels of markers for hepatic damage (alanine aminotransferase and aspartate aminotransferase) were increased. In conclusion, chorioamnionitis induces liver inflammation leading to metabolic disturbances in the fetus.

Fetal asphyxia leads to a decrease in dorsal raphe serotonergic neurons.

The aim of the present study was to determine the effects of fetal asphyxia (FA) on anxiety and serotonergic neurons in young adult and middle-aged rats. FA was induced at embryonic day 17 by clamping the uterine circulation for 75 min. Anxiety-related behavior was tested in an open field, and design-based stereology was used for counting serotonergic (5-hydroxytryptamine/serotonin, 5-HT) neurons in the dorsal raphe nucleus (DRN). The open field revealed increased anxiety in the 19-month-old FA rats in comparison to control animals. No significant differences were found in DRN 5-HT neuron numbers at 6 months. At 19 months, however, FA significantly lowered the mean density and volume of 5-HT neurons in the DRN as compared to controls. Further, an age-related reduction was found in the total number, the mean density and the mean volume of 5-HT neurons within the FA group. In conclusion, FA is associated with increased anxiety and age-related changes in 5-HT immunohistochemistry within the DRN. These results support the notion that insults caused by asphyxiation during critical periods of brain development could create a predisposition to serotonergic abnormalities and anxiety deficits in adulthood.

Lipopolysaccharide-Induced Chorioamnionitis Is Confined to One Amniotic Compartment in Twin Pregnant Sheep

Background: Chorioamnionitis is a major risk factor for preterm birth in multifetal pregnancies. However, there is little clinical data whether chorioamnionitis is restricted to one amniotic compartment in multifetal pregnancies. Objective: To explore whether chorioamnionitis is confined to the exposed compartment and does not cross to the unaffected fetus in twin pregnancy. Methods: In twin pregnant sheep, one of the twins was exposed to either 2 or 14 days of intra-amniotic lipopolysaccharide (LPS) while the co-twin was exposed to either 2 or 14 days of intra-amniotic saline (n = 3 for each exposure). Singletons were included in this study to compare the grade of inflammation with twins. All fetuses were delivered at 125 days of gestation (term = 150 days). Chorioamnionitis was confirmed by histological examination. Lung inflammation was assessed by cell count in bronchoalveolar lavage. Lung compliance was assessed at 40 cm H2O. Results were compared using analysis of variance (ANOVA) with a post-hoc Tukey analysis. Results: Inflammation in placenta, membranes and lung of LPS-exposed twins was significantly higher after 2 and 14 days of exposure when compared to the saline-exposed co-twins. Lung compliance in LPS-exposed twins was significantly increased after 14 days when compared to saline-exposed co-twins. Intrauterine LPS exposure increased lung compliance and inflammation in the membranes, placenta and lung to the same extent in twins as in singletons. Conclusion: In twin pregnant sheep, inflammation of the membranes, placenta and fetal lung was strictly limited to the exposed fetus in the amniotic compartment in which the LPS was injected.

Early Erythropoietin for Preventing Red Blood Cell Transfusion in Preterm and/or Low Birth Weight Infants

Early administration of EPO reduces the use of RBC transfusions and the volume of RBCs transfused. These small reductions are of limited clinical importance. Donor exposure is probably not avoided since most studies included infants who had received RBC transfusions prior to trial entry. There was a significant increase in the rate of ROP (stage 3 or greater). Early EPO does not significantly decrease or increase any of the other important adverse outcomes. Ongoing research should deal with the issue of ROP and evaluate the current clinical practice that will limit donor exposure. Due to the limited benefits and the increased risk of ROP, early administration of EPO is not recommended. Evidence is lacking for the possible neuroprotective role of EPO in preterm infants.

The influence of anesthetics on substantia nigra tyrosine hydroxylase expression and tau phosphorylation in the hypoxic–ischemic near-term lamb

BackgroundGeneral anesthetics could protect key neurotransmitter systems, such as the dopaminergic system, from hypoxic–ischemic encephalopathy (HIE) by limiting excessive glutamatergic neurotransmission. However, anesthetics may adversely affect inflammation and tau phosphorylation.MethodsA near-term sheep model of HIE by umbilical cord occlusion (UCO) under anesthesia was used. The effect of propofol and isoflurane on the dopaminergic neurotransmitter phenotype in the substantia nigra (SN) was studied using tyrosine hydroxylase immunohistochemistry. The overall microglial response and tau phosphorylation were also measured in the SN, surrounding the midbrain gray matter structures and the hippocampal white matter.ResultsThe isoflurane-treated UCO group had fewer tyrosine hydroxylase-expressing neurons in the SN at 8 h after the insult than the propofol-treated UCO or sham-operated groups (P<0.05). The microglial response was unchanged in the SN region. In the thalamus and the hippocampal stratum moleculare layer, the propofol-treated UCO group had a lower microglial response than the corresponding sham-operated group. Both UCO and the use of anesthetics additively increased tau phosphorylation in the SN region, thalamus, and hippocampus.ConclusionThe choice of anesthetics is important for an emergency C-section. Propofol could potentially protect the dopaminergic neurotransmitter phenotype within the SN at the cost of a widespread increase in tau phosphorylation.

Perinatal insults and neurodevelopmental disorders may impact Huntington's disease age of diagnosis

Introduction The age of diagnosis of Huntingtons disease (HD) varies among individuals with the same HTT CAG-repeat expansion size. We investigated whether early-life events, like perinatal insults or neurodevelopmental disorders, influence the diagnosis age. Methods We used data from 13,856 participants from REGISTRY and Enroll-HD, two large international multicenter observational studies. Disease-free survival analyses of mutation carriers with an HTT CAG repeat expansion size above and including 36 were computed through Kaplan-Meier estimates of median time until an HD diagnosis. Comparisons between groups were computed using a Cox proportional hazard survival model adjusted for CAG-repeat expansion length. We also assessed whether the group effect depended on gender and the affected parent. Results Insults in the perinatal period were associated with an earlier median age of diagnosis of 45.00 years (95%CI: 42.07–47.92) compared to 51.00 years (95%CI: 50.68–51.31) in the reference group, with a CAG-adjusted hazard ratio of 1.61 (95%CI: 1.26–2.06). Neurodevelopmental disorders were also associated with an earlier median age of diagnosis than the reference group of 47.00 years (95% CI: 43.38–50.62) with a CAG-adjusted hazard ratio of 1.42 (95%CI: 1.16–1.75). These associations did not change significantly with gender or affected parent. Conclusions These results, derived from large observational datasets, show that perinatal insults and neurodevelopmental disorders are associated with earlier ages of diagnosis of magnitudes similar to the effects of known genetic modifiers of HD. Given their clear temporal separation, these early events may be causative of earlier HD onset, but further research is needed to prove causation.