The effects of anaesthesia on cell death in a porcine model of neonatal hypoxic-ischaemic brain injury

Background: Hypothermia is neuroprotective after neonatal hypoxic-ischaemic brain injury. However, systemic cooling to hypothermic temperatures is a stressor and may reduce neuroprotection in awake pigs. We compared two experiments of global hypoxic-ischaemic injury in newborn pigs, in which one group received propofol–remifentanil and the other remained awake during post-insult hypothermia treatment. Methods: In both studies, newborn pigs were anaesthetised using halothane during a 45-min global hypoxic-ischaemic insult induced by reducing Fio2 and graded hypotension until a low-voltage <7 μV electroencephalogram was achieved. On reoxygenation, the pigs were randomly allocated to receive 24 h of normothermia or hypothermia. In the first study (n=18) anaesthesia was discontinued and the pigs' tracheas were extubated. In the second study (n=14) anaesthesia was continued using propofol and remifentanil. Brain injury was assessed after 72 h by classical global histopathology, Purkinje cell count, and apoptotic cell counts in the hippocampus and cerebellum. Results: Global injury was nearly 10-fold greater in the awake group compared with the anaesthetised group (P=0.021). Hypothermia was neuroprotective in the anaesthetised pigs but not the awake pigs. In the hippocampus, the density of cleaved caspase-3-positive cells was increased in awake compared with anaesthetised pigs in normothermia. In the cerebellum, Purkinje cell density was reduced in the awake pigs irrespective of treatment, and the number of cleaved caspase-3-positive Purkinje cells was greatly increased in hypothermic awake pigs. We detected no difference in cleaved caspase-3 in the granular cell layer or microglial reactivity across the groups. Conclusions: Our study provides novel insights into the significance of anaesthesia/sedation during hypothermia for achieving optimal neuroprotection

Resting-state functional connectivity in children cooled for neonatal encephalopathy

This is the final version. Available from Oxford University Press via the DOI in this record. Therapeutic hypothermia improves outcomes following neonatal hypoxic-ischaemic encephalopathy, reducing cases of death and severe disability such as cerebral palsy compared with normothermia management. However, when cooled children reach early school-age, they have cognitive and motor impairments which are associated with underlying alterations to brain structure and white matter connectivity. It is unknown whether these differences in structural connectivity are associated with differences in functional connectivity between cooled children and healthy controls. Resting-state functional MRI has been used to characterize static and dynamic functional connectivity in children, both with typical development and those with neurodevelopmental disorders. Previous studies of resting-state brain networks in children with hypoxic-ischaemic encephalopathy have focussed on the neonatal period. In this study, we used resting-state fMRI to investigate static and dynamic functional connectivity in children aged 6–8 years who were cooled for neonatal hypoxic-ischaemic without cerebral palsy [n = 22, median age (interquartile range) 7.08 (6.85–7.52) years] and healthy controls matched for age, sex and socioeconomic status [n = 20, median age (interquartile range) 6.75 (6.48–7.25) years]. Using group independent component analysis, we identified 31 intrinsic functional connectivity networks consistent with those previously reported in children and adults. We found no case-control differences in the spatial maps of these intrinsic connectivity networks. We constructed subject-specific static functional connectivity networks by measuring pairwise Pearson correlations between component time courses and found no case-control differences in functional connectivity after false discovery rate correction. To study the time-varying organization of resting-state networks, we used sliding window correlations and deep clustering to investigate dynamic functional connectivity characteristics. We found k = 4 repetitively occurring functional connectivity states, which exhibited no case-control differences in dwell time, fractional occupancy or state functional connectivity matrices. In this small cohort, the spatiotemporal characteristics of resting-state brain networks in cooled children without severe disability were too subtle to be differentiated from healthy controls at early school-age, despite underlying differences in brain structure and white matter connectivity, possibly reflecting a level of recovery of healthy resting-state brain function. To our knowledge, this is the first study to investigate resting-state functional connectivity in children with hypoxic-ischaemic encephalopathy beyond the neonatal period and the first to investigate dynamic functional connectivity in any children with hypoxic-ischaemic encephalopathy.Baily Thomas Charitable FundDavid Telling Charitable TrustDavid Telling Charitable TrustWellcome TrustMedical Research CouncilMoulton Foundatio

Mammillary body abnormalities and cognitive outcomes in children cooled for neonatal encephalopathy

Aim: To evaluate mammillary body abnormalities in school-age children without cerebral palsy treated with therapeutic hypothermia for neonatal hypoxic–ischaemic encephalopathy (cases) and matched controls, and associations with cognitive outcome, hippocampal volume, and diffusivity in the mammillothalamic tract (MTT) and fornix. Method: Mammillary body abnormalities were scored from T1-weighted magnetic resonance imaging (MRI) in 32 cases and 35 controls (median age [interquartile range] 7 years [6 years 7 months–7 years 7 months] and 7 years 4 months [6 years 7 months–7 years 7 months] respectively). Cognition was assessed using the Wechsler Intelligence Scale for Children, Fourth Edition. Hippocampal volume (normalized by total brain volume) was measured from T1-weighted MRI. Radial diffusivity and fractional anisotropy were measured in the MTT and fornix, from diffusion-weighted MRI using deterministic tractography. Results: More cases than controls had mammillary body abnormalities (34% vs 0%; p < 0.001). Cases with abnormal mammillary bodies had lower processing speed (p = 0.016) and full-scale IQ (p = 0.028) than cases without abnormal mammillary bodies, and lower scores than controls in all cognitive domains (p < 0.05). Cases with abnormal mammillary bodies had smaller hippocampi (left p = 0.016; right p = 0.004) and increased radial diffusivity in the right MTT (p = 0.004) compared with cases without mammillary body abnormalities. Interpretation: Cooled children with mammillary body abnormalities at school-age have reduced cognitive scores, smaller hippocampi, and altered MTT microstructure compared with those without mammillary body abnormalities, and matched controls

Neonatal retroauricular cellulitis as an indicator of group B streptococcal bacteremia: a case report

<p>Abstract</p> <p>Introduction</p> <p>The relation between cellulitis and Group B streptococcus infection in newborns and small infants was first reported during the early 1980s and named cellulitis-adenitis syndrome. We report a case of a neonate with cellulitis-adenitis syndrome in an unusual location (retroauricular).</p> <p>Case presentation</p> <p>A 21-day-old Caucasian female infant was brought to the emergency department with fever, irritability and a decreased appetite. Physical examination revealed erythema and painful, mild swelling in the right retroauricular region. The blood count and C-reactive protein level were normal. She was treated with ceftriaxone. The fever and irritability were resolved after 24 hours, and the cellulitis was clearly reduced after two days of hospitalization. Blood culture yielded Group B streptococcus.</p> <p>Conclusion</p> <p>A thorough evaluation must be done, and lumbar punctures for infants with cellulitis must be considered. We emphasize the lack of data about acute phase reactants to predict bacteremia and meningitis and to adjust the duration of parenteral antibiotic therapy to address this syndrome.</p

Neuronal let-7b-5p acts through the Hippo-YAP pathway in neonatal encephalopathy

Despite increasing knowledge on microRNAs, their role in the pathogenesis of neonatal encephalopathy remains to be elucidated. Herein, we identify let-7b-5p as a significant microRNA in neonates with moderate to severe encephalopathy from dried blood spots using next generation sequencing. Validation studies using Reverse Transcription and quantitative Polymerase Chain Reaction on 45 neonates showed that let-7b-5p expression was increased on day 1 in neonates with moderate to severe encephalopathy with unfavourable outcome when compared to those with mild encephalopathy. Mechanistic studies performed on glucose deprived cell cultures and the cerebral cortex of two animal models of perinatal brain injury, namely hypoxic-ischaemic and intrauterine inflammation models confirm that let-7b-5p is associated with the apoptotic Hippo pathway. Significant reduction in neuronal let-7b-5p expression corresponded with activated Hippo pathway, with increased neuronal/nuclear ratio of Yes Associated Protein (YAP) and increased neuronal cleaved caspase-3 expression in both animal models. Similar results were noted for let-7b-5p and YAP expression in glucose-deprived cell cultures. Reduced nuclear YAP with decreased intracellular let-7b-5p correlated with neuronal apoptosis in conditions of metabolic stress. This finding of the Hippo-YAP association with let-7b needs validation in larger cohorts to further our knowledge on let-7b-5p as a biomarker for neonatal encephalopathy

Biomarkers of hepatic injury and function in neonatal hypoxic ischemic encephalopathy and with therapeutic hypothermia

Therapeutic hypothermia (TH) is now provided as standard care to infants with moderate-severe hypoxic ischemic encephalopathy (HIE). The role of TH in limiting neuronal injury is well recognized, but its effect on hepatic injury which occurs frequently in neonatal HIE is not known. Our objective was to characterize biomarkers of liver injury and function in the setting of neonatal HIE and to describe whether HIE severity and provision of TH influence these hepatic biomarkers. We performed a multicenter retrospective study and compared hepatic biomarkers obtained during the first postnatal week, according to the severity of HIE and whether treated with TH. Of a total of 361 infants with HIE, 223 (62%) received TH and 138 (38%) were managed at normal temperature. Most hepatic biomarkers and C-reactive protein (CRP) were significantly associated with the severity of HIE (p<0.001). Infants treated with TH had lower peak Alanine aminotransferase (ALT) concentrations (p=0.025) and delay in reaching peak CRP concentration (p<0.001).  Conclusion: We observed a significant association between the clinical grade of HIE and biomarkers of liver metabolism and function. Therapeutic hypothermia was associated with delayed CRP responses and with lower ALT concentrations and so may have the potential to modulate hepatic injury