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With the current practice of therapeutic hypothermia for neonatal encephalopathy, disability rates and the severity spectrum of cerebral palsy are reduced. Nevertheless, safe and effective adjunct therapies are needed to optimize outcomes. This study's objective was to assess if 18 mg/kg melatonin given rapidly over 2 h at 1 h after hypoxia-ischemia with cooling from 1-13 h was safe, achieved therapeutic levels within 3 h and augmented hypothermic neuroprotection. Following hypoxia-ischemia, 20 newborn piglets were randomized to: (i) Cooling 1-13 h (HT; n = 6); (ii) HT+ 2.5% ethanol vehicle (Ht+V; n = 7); (iii) HT + Melatonin (Ht+M; n = 7). Intensive care was maintained for 48 h; aEEG was acquired throughout, brain MRS acquired at 24 and 48 h and cell death (TUNEL) evaluated at 48 h. There were no differences for insult severity. Core temperature was higher in HT group for first hour after Hi. comparing Ht+M to HT, aEEG scores recovered more quickly by 19 h (p < 0.05); comparing HT+V to HT, aEEG recovered from 31 h (p < 0.05). Brain phosphocreatine/inorganic phosphate and NTP/ exchangeable phosphate were higher at 48 h in HT+M versus Ht (p = 0.036, p = 0.049 respectively). Including both 24 h and 48 h measurements, the rise in Lactate/N-acetyl aspartate was reduced in white (p = 0.030) and grey matter (p = 0.038) after HI. Reduced overall TUNEL positive cells were observed in Ht+M (47.1 cells/mm 2 ) compared to HT (123.8 cells/mm 2 ) (p = 0.0003) and HT+V (97.5 cells/mm 2 ) compared to Ht (p = 0.012). Localized protection was seen in white matter for HT+M versus Ht (p = 0.036) and internal capsule for HT+M compared to Ht (p = 0.001) and HT+V versus Ht (p = 0.006). Therapeutic melatonin levels (15-30mg/l) were achieved at 2 h and were neuroprotective following HI, but ethanol vehicle was partially protective.Intrapartum-related neonatal encephalopathy (NE) is a major healthcare problem. Worldwide in 2010, NE accounted for 287,000 deaths and 400,000 survivors with impairment 1 . NE cannot be prevented in most cases and therapies are limited. The incidence of NE in Western Europe is 1-3/1000 term births and in low-and mid-resource settings the incidence is ~10 times higher 1,2 . Over the last 2 decades, in settings with neonatal intensive care facilities, therapeutic hypothermia (HT) is routinely used for moderate-to-severe NE, improving survival and reducing disability 3 . However, although the severity of cerebral palsy has reduced with HT 4 , survivors have significantly lower cognitive scores which are on average 14 IQ points lower than matched peers even in the absence of cerebral palsy at school-age 5 . Further adjustments to HT protocols do not improve outcome 6,7 , therefore adjunct therapies to augment HT protection are urgently needed.Pre-clinical studies suggest that melatonin (N-acetyl-5-methoxytryptamine) in pharmacologic levels is safe and neuroprotective for hypoxic-ischemic injury in the adult 8 and neonatal 9 brain, mediated by anti-oxidant, anti-apoptotic and anti-inflammatory properties 10,11 . Ex...

Co-existing infection/inflammation and birth asphyxia potentiate the risk of developing neonatal encephalopathy (NE) and adverse outcome. In a newborn piglet model we assessed the effect of E. coli lipopolysaccharide (LPS) infusion started 4 h prior to and continued for 48 h after hypoxia on brain cell death and systemic haematological changes compared to LPS and hypoxia alone. LPS sensitized hypoxia resulted in an increase in mortality and in brain cell death (TUNEL positive cells) throughout the whole brain, and in the internal capsule, periventricular white matter and sensorimotor cortex. LPS alone did not increase brain cell death at 48 h, despite evidence of neuroinflammation, including the greatest increases in microglial proliferation, reactive astrocytosis and cleavage of caspase-3. LPS exposure caused splenic hypertrophy and platelet count suppression. The combination of LPS and hypoxia resulted in the highest and most sustained systemic white cell count increase. These findings highlight the significant contribution of acute inflammation sensitization prior to an asphyxial insult on NE illness severity.

Background Perinatal inflammation combined with hypoxia–ischemia (HI) exacerbates injury in the developing brain. Therapeutic hypothermia (HT) is standard care for neonatal encephalopathy; however, its benefit in inflammation-sensitized HI (IS-HI) is unknown. Methods Twelve newborn piglets received a 2 µg/kg bolus and 1 µg/kg/h infusion over 52 h of Escherichia coli lipopolysaccharide (LPS). HI was induced 4 h after LPS bolus. After HI, piglets were randomized to HT (33.5 °C 1–25 h after HI, n = 6) or normothermia (NT, n = 6). Amplitude-integrated electroencephalogram (aEEG) was recorded and magnetic resonance spectroscopy (MRS) was acquired at 24 and 48 h. At 48 h, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive brain cell death, microglial activation/proliferation, astrogliosis, and cleaved caspase-3 (CC3) were quantified. Hematology and plasma cytokines were serially measured. Results Two HT piglets died. aEEG recovery, thalamic and white matter MRS lactate/N-acetylaspartate, and TUNEL-positive cell death were similar between groups. HT increased microglial activation in the caudate, but had no other effect on glial activation/proliferation. HT reduced CC3 overall. HT suppressed platelet count and attenuated leukocytosis. Cytokine profile was unchanged by HT. Conclusions We did not observe protection with HT in this piglet IS-HI model based on aEEG, MRS, and immunohistochemistry. Immunosuppressive effects of HT and countering neuroinflammation by LPS may contribute to the observed lack of HT efficacy. Other immunomodulatory strategies may be more effective in IS-HI. Impact Acute infection/inflammation is known to exacerbate perinatal brain injury and can worsen the outcomes in neonatal encephalopathy. Therapeutic HT is the current standard of care for all infants with NE, but the benefit in infants with coinfection/inflammation is unknown. In a piglet model of inflammation (LPS)-sensitized HI, we observed no evidence of neuroprotection with cooling for 24 h, based on our primary outcome measures: aEEG, MRS Lac/NAA, and histological brain cell death. Additional neuroprotective agents, with beneficial immunomodulatory effects, require exploration in IS-HI models.