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Erythropoietin (EPO) is being trialled in preterm infants to reduce brain injury, but high doses increase lung injury in ventilated preterm lambs. We aimed to determine whether early administration of lower doses of EPO could reduce ventilation-induced lung injury and systemic inflammation in preterm lambs. Ventilation was initiated in anaesthetized preterm lambs [125 ± 1 (SD) days gestation] using an injurious strategy for the first 15 min. Lambs were subsequently ventilated with a protective strategy for a total of 2 h. Lambs were randomized to receive either intravenous saline (Vent; n = 7) or intravenous 300 ( n = 5), 1,000 (EPO1000; n = 5), or 3,000 (EPO3000; n = 5) IU/kg of human recombinant EPO via an umbilical vein. Lung tissue was collected for molecular and histological assessment of inflammation and injury and compared with unventilated control lambs (UVC; n = 8). All ventilated groups had similar blood gas and ventilation parameters, but EPO1000 lambs had a lower fraction of inspired oxygen requirement and lower alveolar–arterial difference in oxygen. Vent and EPO lambs had increased lung interleukin (IL)-1β, IL-6, and IL-8 mRNA, early lung injury genes connective tissue growth factor, early growth response protein 1, and cysteine-rich 61, and liver serum amyloid A3 mRNA compared with UVCs; no difference was observed between Vent and EPO groups. Histological lung injury was increased in Vent and EPO groups compared with UVCs, but EPO3000 lambs had increased lung injury scores compared with VENT only. Early low-doses of EPO do not exacerbate ventilation-induced lung inflammation and injury and do not provide any short-term respiratory benefit. High doses (≥3,000 IU/kg) likely exacerbate lung inflammation and injury in ventilated preterm lambs. NEW & NOTEWORTHY Trials are ongoing to assess the efficacy of erythropoietin (EPO) to provide neuroprotection for preterm infants. However, high doses of EPO increase ventilation-induced lung injury (VILI) in preterm lambs. We investigated whether early lower doses of EPO may reduce VILI. We found that lower doses did not reduce, but did not increase, VILI, while high doses (≥3,000 IU/kg) increase VILI. Therefore, lower doses of EPO should be used in preterm infants, particularly those receiving respiratory support.

Mechanical ventilation of preterm neonates causes lung inflammation and injury, with potential life-long consequences. Inert 50-nm polystyrene nanoparticles (PS50G) reduce allergic inflammation in the lungs of adult mice. We aimed to confirm the anti-inflammatory effects of PS50G in a sheep asthma model, and investigate the effects of prophylactic administration of PS50G on ventilation-induced lung injury (VILI) in preterm lambs. We assessed lung inflammatory cell infiltration, with and without PS50G, after airway allergen challenge in ewes sensitised to house dust mite. Preterm lambs (0.83 gestation) were delivered by caesarean section for immediate tissue collection (n = 5) or ventilation either with (n = 6) or without (n = 5) prophylactic intra-tracheal administration of PS50G nanoparticles (3% in 2 ml). Ventilation was continued for a total of 2 h before tissue collection for histological and biomolecular assessment of lung injury and inflammation. In ewes with experimental asthma, PS50G decreased eosinophilic infiltration of the lungs. Ventilated preterm lambs showed molecular and histological signs of lung injury and inflammation, which were exacerbated in lambs that received PSG50G. PS50G treatment decreased established inflammation in the lungs of asthmatic sheep. However, prophylactic administration of PSG50 exacerbated ventilation-induced lung injury and lung inflammation in preterm lambs.

Erythropoietin (EPO) is being trialed in preterm neonates for neuroprotection. We have recently demonstrated that a single high bolus dose (5,000 IU/kg) of recombinant human EPO amplified preterm lung and brain ventilation-induced injury. We aimed to determine the optimal dose of EPO to reduce ventilation-induced cerebral white matter inflammation and injury in preterm lambs. Lambs (0.85 gestation) were ventilated with an injurious strategy for 15 min followed by conventional ventilation for 105 min. Lambs were randomized to no treatment (VENT; n = 8) or received a bolus dose of EPO (EPREX®): 300 IU/kg (EPO 300; n = 5), 1,000 IU/kg (EPO 1,000; n = 5), or 3,000 IU/kg (EPO 3,000; n = 5). Physiological parameters were measured throughout the study. After 2 h, brains were collected for analysis; real-time quantitative polymerase chain reaction and immunohistochemistry were used to assess inflammation, cell death, and vascular leakage in the periventricular and subcortical white matter (PVWM; SCWM). Molecular and histological inflammatory indices in the PVWM were not different between groups. EPO 300 lambs had higher IL-6 (p = 0.006) and caspase-3 (p = 0.025) mRNA expression in the SCWM than VENT lambs. Blood-brain barrier (BBB) occludin mRNA levels were higher in EPO 3,000 lambs in the PVWM and SCWM than VENT lambs. The number of blood vessels with protein extravasation in the SCWM was lower in EPO 1,000 (p = 0.010) and EPO 3,000 (p = 0.025) lambs compared to VENT controls but not different between groups in the PVWM. Early administration of EPO at lower doses neither reduced nor exacerbated cerebral white matter inflammation or injury. 3,000 IU/kg EPO may provide neuroprotection by improving BBB integrity.

Acute kidney injury affects ~70% of asphyxiated newborns, and increases their risk of developing chronic kidney disease later in life. Acute kidney injury is driven by renal oxygen deprivation during asphyxia, thus we hypothesized that creatine administered antenatally would protect the kidney from the long-term effects of birth asphyxia.Pregnant spiny mice were fed standard chow or chow supplemented with 5% creatine from 20-d gestation (midgestation). One day prior to term (37-d gestation), pups were delivered by caesarean or subjected to intrauterine asphyxia. Litters were allocated to one of two time-points. Kidneys were collected at 1 mo of age to estimate nephron number (stereology). Renal function (excretory profile and glomerular filtration rate) was measured at 3 mo of age, and kidneys then collected for assessment of glomerulosclerosis.Compared with controls, at 1 mo of age male (but not female) birth-asphyxia offspring had 20% fewer nephrons (P0.05). At 3 mo of age male birth-asphyxia offspring had 31% lower glomerular filtration rate (P0.05) and greater glomerular collagen IV content (P0.01). Antenatal creatine prevented these renal injuries arising from birth asphyxia.Maternal creatine supplementation during pregnancy may be an effective prophylactic to prevent birth asphyxia induced acute kidney injury and the emergence of chronic kidney disease.

Aim Pneumothorax is a common emergency affecting extremely preterm. In adult studies, lung ultrasound has performed better than chest x-ray in the diagnosis of pneumothorax. The purpose of this study was to determine the efficacy of lung ultrasound (LUS) examination to detect pneumothorax using a preterm animal model. Methods This was a prospective, observational study using newborn Border–Leicester lambs at gestational age = 126 days (equivalent to gestational age = 26 weeks in humans) receiving mechanical ventilation from birth to 2 h of life. At the conclusion of the experiment, LUS was performed, the lambs were then euthanised and a post-mortem exam was immediately performed. We used previously published ultrasound techniques to identify pneumothorax. Test characteristics of LUS to detect pneumothorax were calculated, using the post-mortem exam as the ‘gold standard’ test. Results Nine lambs (18 lungs) were examined. Four lambs had a unilateral pneumothorax, all of which were identified by LUS with no false positives. Conclusions This was the first study to use post-mortem findings to test the efficacy of LUS to detect pneumothorax in a newborn animal model. Lung ultrasound accurately detected pneumothorax, verified by post-mortem exam, in premature, newborn lambs.

BackgroundPhysiologically based cord clamping (PBCC) has advantages over immediate cord clamping (ICC) during preterm delivery, but its efficacy in asphyxiated infants is not known. We investigated the physiology of PBCC following perinatal asphyxia in near-term lambs.MethodsNear-term sheep fetuses (139±2 (SD) days’ gestation) were instrumented to measure umbilical, carotid, pulmonary and femoral arterial flows and pressures. Systemic and cerebral oxygenation was recorded using pulse oximetry and near-infrared spectroscopy, respectively. Fetal asphyxia was induced until mean blood pressure reached ~20 mm Hg, where lambs underwent ICC and initiation of ventilation (n=7), or ventilation for 15 min prior to umbilical cord clamping (PBCC; n=8). Cardiovascular parameters were measured and white and grey matter microvascular integrity assessed using qRT-PCR and immunohistochemistry.ResultsPBCC restored oxygenation and cardiac output at the same rate and in a similar fashion to lambs resuscitated following ICC. However, ICC lambs had a rapid and marked overshoot in mean systemic arterial blood pressure from 1 to 10 min after ventilation onset, which was largely absent in PBCC lambs. ICC lambs had increased cerebrovascular injury, as indicated by reduced expression of blood–brain barrier proteins and increased cerebrovascular protein leakage in the subcortical white matter (by 86%) and grey matter (by 47%).ConclusionPBCC restored cardiac output and oxygenation in an identical time frame as ICC, but greatly mitigated the postasphyxia rebound hypertension measured in ICC lambs. This likely protected the asphyxiated brain from cerebrovascular injury. PBCC may be a more suitable option for the resuscitation of the asphyxiated newborn compared with the current standard of ICC.

Background: Delaying umbilical cord clamping until after aeration of the lung (physiological-based cord clamping; PBCC) maintains cardiac output and oxygenation in preterm lambs at birth, however, its efficacy after intrauterine inflammation is not known. Given the high incidence of chorioamnionitis in preterm infants, we investigated whether PBCC conferred any benefits compared to immediate cord clamping (ICC) in preterm lambs exposed antenatally to 7 days of intrauterine inflammation. Methods: Ultrasound guided intraamniotic injection of 20 mg Lipopolysaccharide (from E. coli:055:B5) was administered to pregnant ewes at 0.8 gestation. Seven days later, ewes were anesthetized, preterm fetuses exteriorised via cesarean section, and instrumented for continuous measurement of pulmonary, systemic and cerebral pressures and flows, and systemic, and cerebral oxygenation. Lambs were then randomized to either PBCC, whereupon ventilation was initiated and maintained for 3 min prior to umbilical cord clamping, or ICC where the umbilical cord was cut and ventilation initiated 30 s later. Ventilation was maintained for 30 min. Results: ICC caused a rapid fall in systemic (by 25%) and cerebral (by 11%) oxygen saturation in ICC lambs, concurrent with a rapid increase in carotid arterial pressure and heart rate. The overshoot in carotid arterial pressure was sustained in ICC lambs for the first 20 min of the study. PBCC maintained cardiac output and prevented the fall in cerebral oxygen delivery at birth. PBCC lambs had lower respiratory compliance and higher respiratory requirements throughout the study. Conclusion: PBCC mitigated the adverse effects of ICC on oxygenation and cardiac output, and therefore could be more beneficial in preterm babies exposed to antenatal inflammation as it maintains cardiac output and oxygen delivery. The increased respiratory requirements require further investigation in this sub-group of preterm infants.

Neonatal hypoxic ischemic encephalopathy (HIE) resulting from intrapartum asphyxia is a global problem that causes severe disabilities and up to 1 million deaths annually. A variant form of activated protein C, 3K3A-APC, has cytoprotective properties that attenuate brain injury in models of adult stroke. In this study, we compared the ability of 3K3A-APC and APC (wild-type (wt)) to attenuate neonatal brain injury, using the spiny mouse (Acomys cahirinus) model of intrapartum asphyxia. Pups were delivered at 38 days of gestation (term = 39 days), with an intrapartum hypoxic insult of 7.5 min (intrapartum asphyxia cohort), or immediate removal from the uterus (control cohort). After 1 h, pups received a subcutaneous injection of 3K3A-APC or wild-type APC (wtAPC) at 7 mg/kg, or vehicle (saline). At 24 h of age, pups were killed and brain tissue was collected for measurement of inflammation and cell death using RT-qPCR and histopathology. Intrapartum asphyxia increased weight loss, inflammation, and apoptosis/necrosis in the newborn brain. 3K3A-APC administration maintained body weight and ameliorated an asphyxia-induced increase of TGFβ1 messenger RNA expression in the cerebral cortex, immune cell aggregation in the corpus callosum, and cell death in the deep gray matter and hippocampus. In the cortex, 3K3A-APC appeared to exacerbate the immune response to the hypoxic ischemic insult. While wtAPC reduced cell death in the corpus callosum and hippocampus following intrapartum asphyxia, it increased markers of neuro-inflammation and cell death in control pups. These findings suggest 3K3A-APC administration may be a useful therapy to reduce cell death and neonatal brain injury associated with HIE. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13311-018-0661-0) contains supplementary material, which is available to authorized users.

PURPOSE Injurious mechanical ventilation causes white matter (WM) injury in preterm infants through inflammatory and haemodynamic pathways. The relative contribution of each of these pathways is not known. We hypothesised that in vivo magnetic resonance imaging (MRI) can detect WM brain injury resulting from mechanical ventilation 24 h after preterm delivery. Further we hypothesised that the combination of inflammatory and haemodynamic pathways, induced by umbilical cord occlusion (UCO) increases brain injury at 24 h. METHODS Fetuses at 124±2 days gestation were exposed, instrumented and either ventilated for 15 min using a high tidal-volume (VT) injurious strategy with the umbilical cord intact (INJ; inflammatory pathway only), or occluded (INJ+UCO; inflammatory and haemodynamic pathway). The ventilation groups were compared to lambs that underwent surgery but were not ventilated (Sham), and lambs that did not undergo surgery (unoperated control; Cont). Fetuses were placed back in utero after the 15 min intervention and ewes recovered. Twenty-four hours later, lambs were delivered, placed on a protective ventilation strategy, and underwent MRI of the brain using structural, diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) techniques. RESULTS Absolute MRS concentrations of creatine and choline were significantly decreased in INJ+UCO compared to Cont lambs (P = 0.03, P = 0.009, respectively); no significant differences were detected between the INJ or Sham groups and the Cont group. Axial diffusivities in the internal capsule and frontal WM were lower in INJ and INJ+UCO compared to Cont lambs (P = 0.05, P = 0.04, respectively). Lambs in the INJ and INJ+UCO groups had lower mean diffusivities in the frontal WM compared to Cont group (P = 0.04). DTI colour mapping revealed lower diffusivity in specific WM regions in the Sham, INJ, and INJ+UCO groups compared to the Cont group, but the differences did not reach significance. INJ+UCO lambs more likely to exhibit lower WM diffusivity than INJ lambs. CONCLUSIONS Twenty-four hours after injurious ventilation, DTI and MRS showed increased brain injury in the injuriously ventilated lambs compared to controls. DTI colour mapping threshold approach provides evidence that the haemodynamic and inflammatory pathways have additive effects on the progression of brain injury compared to the inflammatory pathway alone.

Birth asphyxia is a significant global health problem, responsible for ~1.2 million neonatal deaths each year worldwide. Those who survive often suffer from a range of health issues including brain damage - manifesting as cerebral palsy (CP) - respiratory insufficiency, cardiovascular collapse and renal dysfunction, to name a few. Although the majority of research is directed towards reducing the brain injury that results from intrapartum birth asphyxia, the multi-organ injury observed in surviving neonates are of equal importance. Despite the advent of hypothermia therapy for the treatment of hypoxic-ischemic encephalopathy (HIE), treatment options following asphyxia at birth remain limited, particularly in low-resource settings where the incidence of birth asphyxia is highest. Furthermore, although cooling of the neonate results in improved neurological outcomes for a small proportion of treated infants, it does not provide any benefit to the other organ systems affected by asphyxia at birth. The aim of this review is to summarise the current knowledge of the multi-organ effects of intrapartum asphyxia, with particular reference to the findings from our laboratory using the precocial spiny mouse to model birth asphyxia. Furthermore, we reviewed the current treatments available for neonates who have undergone intrapartum asphyxia, and highlight the emergence of maternal dietary creatine supplementation as a preventative therapy, which has been shown to provide multi-organ protection from birth asphyxia-induced injury in our preclinical studies. This cheap and effective nutritional supplement may be the key to reducing birth asphyxia-induced death and disability, particularly in low-resource settings where current treatments are unavailable.

An increased incidence of mental illness disorders is found in children and adolescents born to mothers who experienced an infection-based illness during pregnancy. Animal models to study the prenatal origin of such outcomes of pregnancy have largely used conventional rodents, which are immature (altricial) at birth compared with the human neonate. In this study, we used the precocial spiny mouse (Acomys cahirinus), whose offspring have completed organogenesis at birth, and administered a single subcutaneous injection of a 5 mg/kg dose of the viral mimetic poly I:C (polyriboinosinic-polyribocytidylic acid) at mid gestation (20 days; term is 39 days). Prenatal exposure to poly I:C caused a transient weight loss in the pregnant dam, produced a downregulation of the proinflammatory cytokine tumour necrosis factor-α in the fetal brain, and resulted in abnormalities in sensorimotor gating and reduced social interaction, memory and learning in juvenile offspring. No changes in exploratory activity or anxiety and fear behaviours were found between the treatment groups. This study provides evidence that, in a rodent model that more closely resembles human brain development, prenatal infection can lead to behavioural abnormalities in postnatal life.

We have previously reported that maternal creatine supplementation protects the neonate from hypoxic injury. Here, we investigated whether maternal creatine supplementation altered expression of the creatine synthesis enzymes (arginine:glycine amidinotransferase [AGAT], guanidinoaceteate methyltransferase [GAMT]) and the creatine transporter (solute carrier family 6 [neurotransmitter transporter, creatine] member 8: SLC6A8) in the term offspring. Pregnant spiny mice were fed a 5% creatine monohydrate diet from midgestation (day 20) to term (39 days). Placentas and neonatal kidney, liver, heart, and brain collected at 24 hours of age underwent quantitative polymerase chain reaction and Western blot analysis. Maternal creatine had no effect on the expression of AGAT and GAMT in neonatal kidney and liver, but mRNA expression of AGAT in brain tissues was significantly decreased in both male and female neonates born to mothers who were fed the creatine diet. SLC6A8 expression was not affected by maternal dietary creatine loading in any tissues. Maternal dietary creatine supplementation from midgestation in the spiny mouse did not alter the capacity for creatine synthesis or transport.

Maternal antenatal creatine supplementation protects the brain, kidney, and diaphragm against the effects of birth asphyxia in the spiny mouse. In this study, we examined creatine's potential to prevent damage to axial skeletal muscles.Pregnant spiny mice were fed a control or creatine-supplemented diet from mid-pregnancy, and 1 d before term (39 d), fetuses were delivered by c-section with or without 7.5 min of birth asphyxia. At 24 h or 33 ± 2 d after birth, gastrocnemius muscles were obtained for ex-vivo study of twitch-tension, muscle fatigue, and structural and histochemical analysis.Birth asphyxia significantly reduced cross-sectional area of all muscle fiber types (P0.05), and increased fatigue caused by repeated tetanic contractions at 24 h of age (P0.05). There were fewer (P0.05) Type I and IIa fibers and more (P0.05) Type IIb fibers in male gastrocnemius at 33 d of age. Muscle oxidative capacity was reduced (P0.05) in males at 24 h and 33 d and in females at 24 h only. Maternal creatine treatment prevented all asphyxia-induced changes in the gastrocnemius, improved motor performance.This study demonstrates that creatine loading before birth protects the muscle from asphyxia-induced damage at birth.

The initiation of ventilation in the delivery room is one of the most important but least controlled interventions a preterm infant will face. Tidal volumes (V T) used in the neonatal intensive care unit are carefully measured and adjusted. However, the V Ts that an infant receives during resuscitation are usually unmonitored and highly variable. Inappropriate V Ts delivered to preterm infants during respiratory support substantially increase the risk of injury and inflammation to the lungs and brain. These may cause cerebral blood flow instability and initiate a cerebral inflammatory cascade. The two pathways increase the risk of brain injury and potential life-long adverse neurodevelopmental outcomes. The employment of new technologies, including respiratory function monitors, can improve and guide the optimal delivery of V Ts and reduce confounders, such as leak. Better respiratory support in the delivery room has the potential to improve both respiratory and neurological outcomes in this vulnerable population.

Pneumothorax is a common emergency affecting extremely preterm. In adult studies, lung ultrasound has performed better than chest x-ray in the diagnosis of pneumothorax. The purpose of this study was to determine the efficacy of lung ultrasound (LUS) examination to detect pneumothorax using a preterm animal model.This was a prospective, observational study using newborn Border-Leicester lambs at gestational age = 126 days (equivalent to gestational age = 26 weeks in humans) receiving mechanical ventilation from birth to 2 h of life. At the conclusion of the experiment, LUS was performed, the lambs were then euthanised and a post-mortem exam was immediately performed. We used previously published ultrasound techniques to identify pneumothorax. Test characteristics of LUS to detect pneumothorax were calculated, using the post-mortem exam as the 'gold standard' test.Nine lambs (18 lungs) were examined. Four lambs had a unilateral pneumothorax, all of which were identified by LUS with no false positives.This was the first study to use post-mortem findings to test the efficacy of LUS to detect pneumothorax in a newborn animal model. Lung ultrasound accurately detected pneumothorax, verified by post-mortem exam, in premature, newborn lambs.

Recent evidence obtained from a rodent model of birth asphyxia shows that supplementation of the maternal diet with creatine during pregnancy protects the neonate from multi-organ damage. However, the effect of increasing creatine intake on creatine homeostasis and biosynthesis in females, particularly during pregnancy, is unknown. This study assessed the impact of creatine supplementation on creatine homeostasis, body composition, capacity for de novo creatine synthesis and renal excretory function in non-pregnant and pregnant spiny mice. Mid-gestation pregnant and virgin spiny mice were fed normal chow or chow supplemented with 5 % w/w creatine for 18 days. Weight gain, urinary creatine and electrolyte excretion were assessed during supplementation. At post mortem, body composition was assessed by Dual-energy X-ray absorptiometry, or tissues were collected to assess creatine content and mRNA expression of the creatine synthesising enzymes arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT) and the creatine transporter (CrT1). Protein expression of AGAT and GAMT was also assessed by Western blot. Key findings of this study include no changes in body weight or composition with creatine supplementation; increased urinary creatine excretion in supplemented spiny mice, with increased sodium (P < 0.001) and chloride (P < 0.05) excretion in pregnant dams after 3 days of supplementation; lowered renal AGAT mRNA (P < 0.001) and protein (P < 0.001) expressions, and lowered CrT1 mRNA expression in the kidney (P < 0.01) and brain (P < 0.001). Creatine supplementation had minimal impact on creatine homeostasis in either non-pregnant or pregnant spiny mice. Increasing maternal dietary creatine consumption could be a useful treatment for birth asphyxia.

Using a model of birth asphyxia, we previously reported significant structural and functional deficits in the diaphragm muscle in spiny mice, deficits that are prevented by supplementing the maternal diet with 5% creatine from mid-pregnancy. The long-term effects of this exposure are unknown. Pregnant spiny mice were fed control or 5% creatine-supplemented diet for the second half of pregnancy, and fetuses were delivered by caesarean section with or without 7.5 min of in-utero asphyxia. Surviving pups were raised by a cross-foster dam until 33±2 days of age when they were euthanized to obtain the diaphragm muscle for ex-vivo study of twitch tension and muscle fatigue, and for structural and enzymatic analyses. Functional analysis of the diaphragm revealed no differences in single twitch contractile parameters between any groups. However, muscle fatigue, induced by stimulation of diaphragm strips with a train of pulses (330 ms train/sec, 40 Hz) for 300 sec, was significantly greater for asphyxia pups compared with controls (p

Background Pregnancy induces adaptations in maternal metabolism to meet the increased need for nutrients by the placenta and fetus. Creatine is an important intracellular metabolite obtained from the diet and also synthesised endogenously. Experimental evidence suggests that the fetus relies on a maternal supply of creatine for much of gestation. However, the impact of pregnancy on maternal creatine homeostasis is unclear. We hypothesise that alteration of maternal creatine homeostasis occurs during pregnancy to ensure adequate levels of this essential substrate are available for maternal tissues, the placenta and fetus. This study aimed to describe maternal creatine homeostasis from mid to late gestation in the precocial spiny mouse. Methods Plasma creatine concentration and urinary excretion were measured from mid to late gestation in pregnant (n = 8) and age-matched virgin female spiny mice (n = 6). At term, body composition and organ weights were assessed and tissue total creatine content determined. mRNA expression of the creatine synthesising enzymes arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT), and the creatine transporter (CrT1) were assessed by RT-qPCR. Protein expression of AGAT and GAMT was also assessed by western blot analysis. Results Plasma creatine and renal creatine excretion decreased significantly from mid to late gestation (P < 0.001, P < 0.05, respectively). Pregnancy resulted in increased lean tissue (P < 0.01), kidney (P < 0.01), liver (P < 0.01) and heart (P < 0.05) mass at term. CrT1 expression was increased in the heart (P < 0.05) and skeletal muscle (P < 0.05) at term compared to non-pregnant tissues, and creatine content of the heart (P < 0.05) and kidney (P < 0.001) were also increased at this time. CrT1 mRNA expression was down-regulated in the liver (

During development the Australian fur seal transitions from a terrestrial, maternally dependent pup to an adult marine predator. Adult seals have adaptations that allow them to voluntarily dive at depth for long periods, including increased bradycardic control, increased myoglobin levels and haematocrit. To establish whether the profile of skeletal muscle also changes in line with the development of diving ability, biopsy samples were collected from the trapezius muscle of pups, juveniles and adults. The proportions of different fibre types and their oxidative capacity were determined. Only oxidative fibre types (Type I and IIa) were identified, with a significant change in proportions from pup to adult. There was no change in oxidative capacity of Type I and IIa fibres between pups and juveniles but there was a two-fold increase between juveniles and adults. Myoglobin expression increased between pups and juveniles, suggesting improved oxygen delivery, but with no increase in oxidative capacity, oxygen utilisation within the muscle may still be limited. Adult muscle had the highest oxidative capacity, suggesting that fibres are able to effectively utilise available oxygen during prolonged dives. Elevated levels of total creatine in the muscles of juveniles may act as an energy buffer when fibres are transitioning from a fast to slow fibre type.

While the use of creatine in human pregnancy is yet to be fully evaluated, its long-term use in healthy adults appears to be safe, and its well documented neuroprotective properties have recently been extended by demonstrations that creatine improves cognitive function in normal and elderly people, and motor skills in sleep-deprived subjects. Creatine has many actions likely to benefit the fetus and newborn, because pregnancy is a state of heightened metabolic activity, and the placenta is a key source of free radicals of oxygen and nitrogen. The multiple benefits of supplementary creatine arise from the fact that the creatine-phosphocreatine [PCr] system has physiologically important roles that include maintenance of intracellular ATP and acid–base balance, post-ischaemic recovery of protein synthesis, cerebral vasodilation, antioxidant actions, and stabilisation of lipid membranes. In the brain, creatine not only reduces lipid peroxidation and improves cerebral perfusion, its interaction with the benzodiazepine site of the GABAA receptor is likely to counteract the effects of glutamate excitotoxicity – actions that may protect the preterm and term fetal brain from the effects of birth hypoxia. In this review we discuss the development of creatine synthesis during fetal life, the transfer of creatine from mother to fetus, and propose that creatine supplementation during pregnancy may have benefits for the fetus and neonate whenever oxidative stress or feto-placental hypoxia arise, as in cases of fetal growth restriction, premature birth, or when parturition is delayed or complicated by oxygen deprivation of the newborn.