Melatonin reduces brain injury following inflammation-amplified hypoxia-ischemia in a translational newborn piglet study of neonatal encephalopathy.

There is a need to develop therapies for neonatal encephalopathy (NE) in low- and middle-income countries (LMICs) where the burden of disease is greatest and therapeutic hypothermia (HT) is not effective. We aimed to assess the efficacy of melatonin following inflammation-amplified hypoxia-ischaemia (IA-HI) in the newborn piglet. The IA-HI model accounts for the contribution of infection/inflammation in this setting and HT is not cytoprotective. We hypothesised that intravenous melatonin (5% ethanol, at 20 mg/kg over 2 h at 1 h after HI + 10 mg/kg/12 h between 24 and 60 h) is safe and associated with: (i) reduction in magnetic resonance spectroscopy lactate/N-acetylaspartate (MRS Lac/sNAA); (ii) preservation of phosphorus MRS phosphocreatine/phosphate exchange pool (PCr/Epp); (iii) improved aEEG/EEG recovery and (iv) cytoprotection on immunohistochemistry. Male and female piglets underwent IA-HI by carotid artery occlusion and reduction in FiO2 to 6% at 4 h into Escherichia coli lipopolysaccharide sensitisation (2 µg/kg bolus + 1 µg/kg/h over 12 h). At 1 h after IA-HI, piglets were randomised to HI-saline (n = 12) or melatonin (n = 11). There were no differences in insult severity between groups. Target melatonin levels (15-30 mg/L) were achieved within 3 h and blood ethanol levels were <0.25 g/L. At 60 h, compared to HI-saline, melatonin was associated with a reduction of 0.197 log10 units (95% CrI [-0.366, -0.028], Pr(sup) 98.8%) in basal-ganglia and thalamic Lac/NAA, and 0.257 (95% CrI [-0.676, 0.164], Pr(sup) 89.3%) in white matter Lac/NAA. PCr/Epp was higher in melatonin versus HI-saline (Pr(sup) 97.6%). Melatonin was associated with earlier aEEG/EEG recovery from 19 to 24 h (Pr(sup) 95.4%). Compared to HI-saline, melatonin was associated with increased NeuN+ cell density (Pr(sup) 99.3%) across five of eight regions and reduction in TUNEL-positive cell death (Pr(sup) 89.7%). This study supports the translation of melatonin to early-phase clinical trials. Melatonin is protective following IA-HI where HT is not effective. These data guide the design of future dose-escalation studies in the next phase of the translational pipeline.

The Extracellular Vesicle Citrullinome and Signature in a Piglet Model of Neonatal Seizures.

Neonatal seizures are commonly associated with acute perinatal brain injury, while understanding regarding the downstream molecular pathways related to seizures remains unclear. Furthermore, effective treatment and reliable biomarkers are still lacking. Post-translational modifications can contribute to changes in protein function, and post-translational citrullination, which is caused by modification of arginine to citrulline via the calcium-mediated activation of the peptidylarginine deiminase (PAD) enzyme family, is being increasingly linked to neurological injury. Extracellular vesicles (EVs) are lipid-bilayer structures released from cells; they can be isolated from most body fluids and act as potential liquid biomarkers for disease conditions and response to treatment. As EVs carry a range of genetic and protein cargo that can be characteristic of pathological processes, the current study assessed modified citrullinated protein cargo in EVs isolated from plasma and CSF in a piglet neonatal seizure model, also following phenobarbitone treatment. Our findings provide novel insights into roles for PAD-mediated changes on EV signatures in neonatal seizures and highlight the potential of plasma- and CSF-EVs to monitor responses to treatment.

Mortality and morbidity in preterm infants with congenital heart disease.

AIM: To compare in-hospital mortality and rates of necrotising enterocolitis (NEC), sepsis, IVH and length of invasive respiratory support in preterm infants <36 weeks' gestation with congenital heart disease (CHD) to matched preterm infants without CHD in a single London centre over 13-year period. METHODS: Single-centre retrospective case-control study over the 13-year period from May 2004 to May 2017. RESULTS: Two hundred forty-seven preterm infants with CHD were matched to 494 infants without CHD. Patients with CHD had a significantly increased risk of in-hospital mortality compared to controls (OR 7.39 (95% CI 4.37-12.5); p < 0.001). Preterm infants with CHD had a higher risk of NEC (OR 2.42 (95% CI 1.32-4.45); p = 0.005), sepsis (OR 1.68 (95% CI 1.23-2.28); p = 0.001) and invasive respiratory support ≥28 days (OR 2.34 (95% CI 1.19-4.58); p = 0.017). Risk of IVH was lower in preterm infants with CHD (OR 0.22 (95% CI 0.11-0.42); p = 0.0001). CONCLUSION: Preterm birth with CHD is associated with a higher risk of in-hospital mortality, NEC, sepsis and prolonged invasive respiratory support, but a lower risk of IVH compared to matched controls. In-hospital mortality remains high in moderate-to-late preterm infants with CHD.

Optimizing hemodynamic care in neonatal encephalopathy.

Hemodynamic impairment occurs in up to 80% of infants with neonatal encephalopathy (NE). Not all infants benefit from therapeutic hypothermia (HT); there are some indications that the trajectory of brain injury might be modified by neurologic monitoring and early management over the first 72-h period. It is also possible that optimizing hemodynamic management may further improve outomes. The coupling between cerebral blood flow and cerebral metabolism is disrupted in NE, increasing the vulnerability of the newborn brain to secondary injury. Hemodynamic monitoring is usually limited to blood pressure and functional echocardiographic measurements, which may not accurately reflect brain perfusion. This review explores the evidence base for hemodynamic assessment and management of infants with NE while undergoing HT. We discuss the literature behind a systematic approach to a baby with NE with the aim to define best therapies to optimize brain perfusion and reduce secondary injury.

Methemoglobinemia during the Use of Glyceryl Trinitrate Patches in Neonates: Two Case Reports.

Methemoglobinemia can result in severe hypoxia. It has been frequently reported during the use of inhaled nitric oxide, but can occur where nitrate containing medications are used. Glyceryl trinitrate (GTN) patches have been used in the treatment of digital and limb ischemia in prematurely born infants. Little is known about the pharmacokinetics of GTN when incorporated into patches. Studies of other topical forms of nitroglycerine have shown a wide range of absorption. It is likely that the increased permeability of the prematurely born infant's skin would facilitate absorption. We describe the use of GTN patches in two very prematurely born infants used to treat limb/digit ischemia. This resulted in methemoglobinemia and resultant increase in their supplementary oxygen requirements. Removal of the patches was associated with a reduction in their methemoglobin levels and the supplementary oxygen requirements back to baseline levels. In conclusion, routine monitoring of methemoglobin levels should be undertaken when GTN patches are used in very prematurely born infants.