Maternal creatine homeostasis is altered during gestation in the spiny mouse: is this a metabolic adaptation to pregnancy?

Differential impact of perfluorooctanoic acid and fluorotelomer ethoxylates on placental metabolism in mice

Poly- and perfluoroalkyl substances (PFAS) are a group of compounds with uses in industry and many consumer products. Concerns about the potential health effects of these compounds resulted in regulation by the Stockholm Convention on the use of three of the most common PFAS, including perfluorooctanoic acid (PFOA). Thousands of PFAS remain in production that are unregulated and for which their toxicity is unknown. Our group recently identified a new class of PFAS, fluorotelomer ethoxylates (FTEOs), in indoor dust and industrial wastewater. In this study, we investigated the effect of PFAS on placental metabolism by exposing healthy, pregnant CD-1 mice to PFOA or FTEOs at one of three concentrations (0 ng/L (controls), 5 ng/L, 100 ng/L) (n = 7-8/group). While PFOA is banned and PFOA concentrations in human blood are decreasing, we hypothesize that FTEOs will cause adverse pregnancy outcomes similar to PFOA, the compounds they were meant to replace. Placental tissue samples were collected at embryonic day 17.5 and 1H solid-state magic angle spinning nuclear magnetic resonance spectroscopy was used to determine the relative concentration of placental metabolites (n = 18-20/group). At the highest concentration, the relative concentrations of glucose and threonine were increased and the relative concentration of creatine was decreased in the PFOA-exposed placentas compared to controls (p < 0.05). In contrast, the relative concentrations of asparagine and lysine were decreased and the relative concentration of creatine was increased in the FTEOs-exposed placentas compared to controls (p < 0.05). Partial least squares - discriminant analysis showed the FTEOs-exposed and control groups were significantly separated (p < 0.005) and pathway analysis found four biochemical pathways were perturbed following PFOA exposure, while one pathway was altered following FTEOs exposure. Maternal exposure to PFOA and FTEOs had a significant impact on the placental metabolome, with the effect depending on the pollutant. This work motivates further studies to determine exposure levels and evaluate associations with adverse outcomes in human pregnancies.

Creatine and pregnancy outcomes: a prospective cohort study of creatine metabolism in low-risk pregnant females

BACKGROUND

Physiological adaptations during pregnancy alter nutrient and energy metabolism. Creatine may be important for maintaining cellular energy homeostasis throughout pregnancy. However, the impact of pregnancy on endogenous and exogenous creatine availability has never been comprehensively explored.

OBJECTIVES

To undertake a prospective cohort study and determine the physiological ranges of creatine and associated metabolites throughout human pregnancy.

METHODS

Females with a singleton low-risk pregnancy were recruited at an Australian health service. Maternal blood and urine were collected at 5-time points from 10-36 weeks of gestation, and cord blood and placental samples were collected at birth. Creatine and associated amino acids and metabolites of creatine synthesis were analyzed. Dietary data were captured to determine effects of exogenous creatine intake. Associations between creatine metabolism and neonatal growth parameters were examined.

RESULTS

Two hundred and eighty-two females were included. Maternal plasma creatine remained stable throughout pregnancy [β: -0.003 μM; 95% confidence interval (CI): -0.07, 0.07; P = 0.94], though urinary creatine declined in late gestation (β: 0.38 μM/mmol/L creatinine (CRN); 95% CI: -0.47, -0.29; P < 0.0001). Plasma guanidinoacetate (GAA; the precursor to creatine during endogenous synthesis) fell from 10-29 weeks of gestation before rising until birth (β: -0.38 μM/mmol/L CRN; 95% CI: -0.47, -0.29; P < 0.0001). Urinary GAA followed an opposing pattern (β: 2.52 μM/mmol/L CRN; 95% CI: 1.47, 3.58, P < 0.001). Animal protein intake was positively correlated with maternal plasma creatine until ∼32 weeks of gestation (β: 0.07-0.18 μM; 95% CI: 0.006, 0.25; P ≤ 0.001). There were no links between creatine and neonatal growth, but increased urinary GAA in early pregnancy was associated with a slight reduction in head circumference at birth (β: -0.01 cm; 95% CI: -0.02, -0.004; P = 0.003).

CONCLUSIONS

Although maternal plasma creatine concentrations were highly conserved, creatine metabolism appears to adjust throughout pregnancy. An ability to maintain creatine concentrations through diet and shifts in endogenous synthesis may impact fetal growth. This trial was registered at [registry name] as ACTRN12618001558213.

A multi-tissue metabolome atlas of primate pregnancy

Pregnancy induces dramatic metabolic changes in females; yet, the intricacies of this metabolic reprogramming remain poorly understood, especially in primates. Using cynomolgus monkeys, we constructed a comprehensive multi-tissue metabolome atlas, analyzing 273 samples from 23 maternal tissues during pregnancy. We discovered a decline in metabolic coupling between tissues as pregnancy progressed. Core metabolic pathways that were rewired during primate pregnancy included steroidogenesis, fatty acid metabolism, and arachidonic acid metabolism. Our atlas revealed 91 pregnancy-adaptive metabolites changing consistently across 23 tissues, whose roles we verified in human cell models and patient samples. Corticosterone and palmitoyl-carnitine regulated placental maturation and maternal tissue progenitors, respectively, with implications for maternal preeclampsia, diabetes, cardiac hypertrophy, and muscle and liver regeneration. Moreover, we found that corticosterone deficiency induced preeclampsia-like inflammation, indicating the atlas's potential clinical value. Overall, our multi-tissue metabolome atlas serves as a framework for elucidating the role of metabolic regulation in female health during pregnancy.

Creatine metabolism at the uterine-placental interface throughout gestation in sheep†

The placenta requires high levels of adenosine triphosphate to maintain a metabolically active state throughout gestation. The creatine-creatine kinase-phosphocreatine system is known to buffer adenosine triphosphate levels; however, the role(s) creatine-creatine kinase-phosphocreatine system plays in uterine and placental metabolism throughout gestation is poorly understood. In this study, Suffolk ewes were ovariohysterectomized on Days 30, 50, 70, 90, 110 and 125 of gestation (n = 3-5 ewes/per day, except n = 2 on Day 50) and uterine and placental tissues subjected to analyses to measure metabolites, mRNAs, and proteins related to the creatine-creatine kinase-phosphocreatine system. Day of gestation affected concentrations and total amounts of guanidinoacetate and creatine in maternal plasma, amniotic fluid and allantoic fluid (P < 0.05). Expression of mRNAs for arginine:glycine amidinotransferase, guanidinoacetate methyltransferase, creatine kinase B, and solute carrier 16A12 in endometria and for arginine:glycine amidinotransferase and creatine kinase B in placentomes changed significantly across days of gestation (P < 0.05). The arginine:glycine amidinotransferase protein was more abundant in uterine luminal epithelium on Days 90 and 125 compared to Days 30 and 50 (P < 0.01). The chorionic epithelium of placentomes expressed guanidinoacetate methyltransferase and solute carrier 6A13 throughout gestation. Creatine transporter (solute carrier 6A8) was expressed by the uterine luminal epithelium and trophectoderm of placentomes throughout gestation. Creatine kinase (creatine kinase B and CKMT1) proteins were localized primarily to the uterine luminal epithelium and to the placental chorionic epithelium of placentomes throughout gestation. Collectively, these results demonstrate cell-specific and temporal regulation of components of the creatine-creatine kinase-phosphocreatine system that likely influence energy homeostasis for fetal-placental development.

The Spiny Mouse—A Menstruating Rodent to Build a Bridge From Bench to Bedside

Menstruation, the cyclical breakdown of the uterine lining, is arguably one of evolution's most mysterious reproductive strategies. The complexity and rarity of menstruation within the animal kingdom is undoubtedly a leading contributor to our current lack of understanding about menstrual function and disorders. In particular, the molecular and environmental mechanisms that drive menstrual and fertility dysregulation remain ambiguous, owing to the restricted opportunities to study menstruation and model menstrual disorders in species outside the primates. The recent discovery of naturally occurring menstruation in the Egyptian spiny mouse (Acomys cahirinus) offers a new laboratory model with significant benefits for prospective research in women's health. This review summarises current knowledge of spiny mouse menstruation, with an emphasis on spiral artery formation, inflammation and endocrinology. We offer a new perspective on cycle variation in menstrual bleeding between individual animals, and propose that this is indicative of fertility success. We discuss how we can harness our knowledge of the unique physiology of the spiny mouse to better understand vascular remodelling and its implications for successful implantation, placentation, and foetal development. Our research suggests that the spiny mouse has the potential as a translational research model to bridge the gap between bench to bedside and provide improved reproductive health outcomes for women.

Creatine Supplementation in Women's Health: A Lifespan Perspective

Despite extensive research on creatine, evidence for use among females is understudied. Creatine characteristics vary between males and females, with females exhibiting 70–80% lower endogenous creatine stores compared to males. Understanding creatine metabolism pre- and post-menopause yields important implications for creatine supplementation for performance and health among females. Due to the hormone-related changes to creatine kinetics and phosphocreatine resynthesis, supplementation may be particularly important during menses, pregnancy, post-partum, during and post-menopause. Creatine supplementation among pre-menopausal females appears to be effective for improving strength and exercise performance. Post-menopausal females may also experience benefits in skeletal muscle size and function when consuming high doses of creatine (0.3 g·kg⁻¹·d⁻¹); and favorable effects on bone when combined with resistance training. Pre-clinical and clinical evidence indicates positive effects from creatine supplementation on mood and cognition, possibly by restoring brain energy levels and homeostasis. Creatine supplementation may be even more effective for females by supporting a pro-energetic environment in the brain. The purpose of this review was to highlight the use of creatine in females across the lifespan with particular emphasis on performance, body composition, mood, and dosing strategies.

Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show?

Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementation is relatively well tolerated, especially at recommended dosages (i.e. 3-5 g/day or 0.1 g/kg of body mass/day). Although there are over 500 peer-refereed publications involving creatine supplementation, it is somewhat surprising that questions regarding the efficacy and safety of creatine still remain. These include, but are not limited to: 1. Does creatine lead to water retention? 2. Is creatine an anabolic steroid? 3. Does creatine cause kidney damage/renal dysfunction? 4. Does creatine cause hair loss / baldness? 5. Does creatine lead to dehydration and muscle cramping? 6. Is creatine harmful for children and adolescents? 7. Does creatine increase fat mass? 8. Is a creatine 'loading-phase' required? 9. Is creatine beneficial for older adults? 10. Is creatine only useful for resistance / power type activities? 11. Is creatine only effective for males? 12. Are other forms of creatine similar or superior to monohydrate and is creatine stable in solutions/beverages? To answer these questions, an internationally renowned team of research experts was formed to perform an evidence-based scientific evaluation of the literature regarding creatine supplementation.

Creatine Metabolism in Female Reproduction, Pregnancy and Newborn Health

Creatine metabolism is an important component of cellular energy homeostasis. Via the creatine kinase circuit, creatine derived from our diet or synthesized endogenously provides spatial and temporal maintenance of intracellular adenosine triphosphate (ATP) production; this is particularly important for cells with high or fluctuating energy demands. The use of this circuit by tissues within the female reproductive system, as well as the placenta and the developing fetus during pregnancy is apparent throughout the literature, with some studies linking perturbations in creatine metabolism to reduced fertility and poor pregnancy outcomes. Maternal dietary creatine supplementation during pregnancy as a safeguard against hypoxia-induced perinatal injury, particularly that of the brain, has also been widely studied in pre-clinical in vitro and small animal models. However, there is still no consensus on whether creatine is essential for successful reproduction. This review consolidates the available literature on creatine metabolism in female reproduction, pregnancy and the early neonatal period. Creatine metabolism is discussed in relation to cellular bioenergetics and de novo synthesis, as well as the potential to use dietary creatine in a reproductive setting. We highlight the apparent knowledge gaps and the research “road forward” to understand, and then utilize, creatine to improve reproductive health and perinatal outcomes.

Increased creatine demand during pregnancy in Arginine: Glycine Amidino-Transferase deficiency: a case report

Background

Creatine (Cr), an amino acid derivative, is one of the most important sources of energy acting as both a spatial and temporal energy buffer through its phosphorylated analogue phosphocreatine (PCr) and creatine kinase (CK). Maternal Cr biosynthesis and metabolism seem to play an important role in pregnancy, as shown in preclinical and in healthy human pregnancy studies. Patients with Arginine:Glycine Amidino-Transferase deficiency (AGAT-d), due to the deficit of the first enzyme involved in Cr synthesis, are at a disadvantage due to their failure to synthesize Cr and their dependence on external intake, in contrast to normal subjects, where changes in Cr biosynthesis supply their needs.

We report the outcomes of a pregnancy in an AGAT-d woman, and the challenge we faced in managing her treatment with oral Cr to ensure optimal conditions for her fetus.

Case presentation

A 22-year-old AGAT-d woman referred to our Institute for the management of her first conception at 11 weeks of fetal gestational age. Sonographic monitoring at 20 w GA indicated a reduction of fetal growth, in particular of the head circumference that was below the 3^rd centile. Biochemical monitoring of Cr in biological fluids of the mother revealed a decline of the Cr concentrations, in particular in the urine sample, requiring prompt correction of the Cr dose. At 35 weeks of gestation the patient delivered a male infant, heterozygous for GATM mutation, with normal brain Cr levels; at one year the baby achieved typical developmental milestones.

Conclusions

This rare pregnancy demonstrates that Cr levels in the blood and urine of the mother with AGAT-d decreased since the first months of gestation. The increase of the Cr daily dose administered to the mother seems to have produced beneficial effects also on the fetus.

Metabolomics Identifies Placental Dysfunction and Confirms Flt-1 (FMS-Like Tyrosine Kinase Receptor 1) Biomarker Specificity

Clinical end-stage parameters define the pregnancy disorders preeclampsia and fetal growth restriction while classification of the underlying placental dysfunction is missing and urgently needed. Flt-1 (FMS-like tyrosine kinase receptor 1) is the most promising placenta-derived predictive biomarker for preeclampsia. We aimed to classify placental dysfunction in preeclampsia and fetal growth restriction at delivery by metabolic profiling and authenticate the biomarker Flt-1 for placental dysfunction. We studied 143 pregnancies with or without preeclampsia and/or fetal growth restriction delivered by cesarean section. Metabolic placenta profiles were created by high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and the resulting placental phenotypes obtained by hierarchical clustering. Placental Flt-1 expression (membrane-bound and soluble isoforms combined) and maternal serum Flt-1 expression (soluble isoforms) were analyzed by immunohistochemistry and ELISA, respectively. We identified 3 distinct placenta groups by 21 metabolites and diagnostic outcome parameters; normal placentas, moderate placental dysfunction, and severe placental dysfunction. Increased placental Flt-1 was associated with severe placental dysfunction, and increased serum Flt-1 was associated with moderate and severe placental dysfunction. The preeclamptic pregnancies with and without placental dysfunction could be distinguished by 5 metabolites and placental Flt-1. Placental Flt-1 alone could separate normal pregnancies with and without placental dysfunction. In conclusion, metabolomics could classify placental dysfunction and provide information not identified by traditional diagnostics and metabolites with biomarker potential were identified. Flt-1 was confirmed as precision biomarker for placental dysfunction, substantiating its usefulness for identification of high-risk pregnancies for preeclampsia and fetal growth restriction with placental involvement.

Creatine and pregnancy outcomes, a prospective cohort study in low-risk pregnant women: study protocol

INTRODUCTION

The creatine kinase circuit is central to the regulation of high-energy phosphate metabolism and the maintenance of cellular energy turnover. This circuit is fuelled by creatine, an amino acid derivative that can be obtained from a diet containing animal products, and by synthesis in the body de novo. A recent retrospective study conducted in a cohort of 287 pregnant women determined that maternal excreted levels of creatine may be associated with fetal growth. This prospective study aims to overcome some of the limitations associated with the previous study and thoroughly characterise creatine homeostasis throughout gestation in a low-risk pregnant population.

METHODS AND ANALYSIS

This study is recruiting women with a singleton low-risk pregnancy who are attending Monash Health, in Melbourne, Australia. Maternal blood and urine samples, along with dietary surveys, are collected at five time points during pregnancy and then at delivery. Cord blood and placenta (including membranes and cord) are collected at birth. A biobank of tissue samples for future research is being established. Primary outcome measures will include creatine, creatine kinase and associated metabolites in antenatal bloods and urine, cord bloods and placenta, along with molecular analysis of the creatine transporter (SLC6A8) and synthesising enzymes L - arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT) in placental tissues. Secondary outcome measures include dietary protein intake over pregnancy and any associations with maternal creatine, pregnancy events and birth outcomes.

ETHICS AND DISSEMINATION

Ethical approval was granted in August 2015 from Monash Health (Ref: 14140B) and Monash University (Ref: 7785). Study outcomes will be disseminated at international conferences and published in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

ACTRN12618001558213; Pre-results.

Comparative Proteomic Analysis of Rana chensinensis Oviduct

As one of most important traditional Chinese medicine resources, the oviduct of female Rana chensinensis (Chinese brown frog) was widely used in the treatment of asthenia after sickness or delivery, deficiency in vigor, palpitation, and insomnia. Unlike other vertebrates, the oviduct of Rana chensinensis oviduct significantly expands during prehibernation, in contrast to the breeding period. To explain this phenomenon at the molecular level, the protein expression profiles of Rana chensinensis oviduct during the breeding period and prehibernation were observed using isobaric tags for relative and absolute quantitation (iTRAQ) technique. Then, all identified proteins were used to obtain gene ontology (GO) annotation. Ultimately, KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis was performed to predict the pathway on differentially expressed proteins (DEPs). A total of 4479 proteins were identified, and 312 of them presented different expression profiling between prehibernation and breeding period. Compared with prehibernation group, 86 proteins were upregulated, and 226 proteins were downregulated in breeding period. After KEGG enrichment analysis, 163 DEPs were involved in 6 pathways, which were lysosome, RNA transport, glycosaminoglycan degradation, extracellular matrix (ECM)⁻receptor interaction, metabolic pathways and focal adhesion. This is the first report on the protein profiling of Rana chensinensis oviduct during the breeding period and prehibernation. Results show that this distinctive physiological phenomenon of Rana chensinensis oviduct was mainly involved in ECM⁻receptor interaction, metabolic pathways, and focal adhesion.

Does maternal-fetal transfer of creatine occur in pregnant sheep?

Our aim was to determine the disposition of creatine in ovine pregnancy and whether creatine is transferred across the placenta from mother to fetus. Pregnant ewes received either 1) a continuous intravenous infusion of creatine monohydrate or saline from 122 to 131 days gestation, with maternal and fetal arterial blood and amniotic fluid samples collected daily for creatine analysis and fetal tissues collected at necropsy at 133 days for analysis of creatine content, or 2) a single systemic bolus injection of [¹³C]creatine monohydrate at 130 days of gestation, with maternal and fetal arterial blood, uterine vein blood, and amniotic fluid samples collected before and for 4 h after injection and analyzed for creatine, creatine isotopic enrichment, and guanidinoacetic acid (GAA; precursor of creatine) concentrations. Presence of the creatine transporter-1 (SLC6A8) and l-arginine:glycine amidinotransferase (AGAT; the enzyme synthesizing GAA) proteins were determined by Western blots of placental cotyledons. The 10-day creatine infusion increased maternal plasma creatine concentration three- to fourfold (P < 0.05) without significantly changing fetal arterial, amniotic fluid, fetal tissues, or placental creatine content. Maternal arterial ¹³C enrichment was increased (P < 0.05) after bolus [¹³C]creatine injection without change of fetal arterial ¹³C enrichment. SLC6A8 and AGAT proteins were identified in placental cotyledons, and GAA concentration was significantly higher in uterine vein than maternal artery plasma. Despite the presence of SLC6A8 protein in cotyledons, these results suggest that creatine is not transferred from mother to fetus in near-term sheep and that the ovine utero-placental unit releases GAA into the maternal circulation.

The biomarker and causal roles of homoarginine in the development of cardiometabolic diseases: an observational and Mendelian randomization analysis

High L-homoarginine (hArg) levels are directly associated with several risk factors for cardiometabolic diseases whereas low levels predict increased mortality in prospective studies. The biomarker role of hArg in young adults remains unknown. To study the predictive value of hArg in the development of cardiometabolic risk factors and diseases, we utilized data on high-pressure liquid chromatography-measured hArg, cardiovascular risk factors, ultrasound markers of preclinical atherosclerosis and type 2 diabetes from the population-based Young Finns Study involving 2,106 young adults (54.6% females, aged 24–39). We used a Mendelian randomization approach involving tens to hundreds of thousands of individuals to test causal associations. In our 10-year follow-up analysis, hArg served as an independent predictor for future hyperglycaemia (OR 1.31, 95% CI 1.06–1.63) and abdominal obesity (OR 1.60, 95% 1.14–2.30) in men and type 2 diabetes in women (OR 1.55, 95% CI 1.02–2.41). The MR analysis revealed no evidence of causal associations between serum hArg and any of the studied cardiometabolic outcomes. In conclusion, lifetime exposure to higher levels of circulating hArg does not seem to alter cardiometabolic disease risk. Whether hArg could be used as a biomarker for identification of individuals at risk developing cardiometabolic abnormalities merits further investigation.

Fifteen-year follow-up of Italian families affected by arginine glycine amidinotransferase deficiency

BACKGROUND

Arginine:glycine amidinotransferase deficiency (AGAT-d) is a very rare inborn error of creatine synthesis mainly characterized by absence of brain Creatine (Cr) peak, intellectual disability, severe language impairment and behavioural disorder and susceptible to supplementary Cr treatment per os. Serial examinations by magnetic resonance spectroscopy are required to evaluate Cr recovery in brain during treatment of high doses of Cr per os, which have been proved beneficial and effective in treating main clinical symptoms. A long term study with detailed reports on clinical, neurochemical and neuropsychological outcomes of the first Italian patients affected by AGAT-d here reported can represent a landmark in management of this disorder thus enhancing medical knowledge and clinical practice.

RESULTS

We have evaluated the long term effects of Cr supplementation management in four Italian patients affected by AGAT-d, correlating specific treatments with serial clinical, biochemical and magnetic resonance spectroscopy examinations as well as the neuropsychological outcome by standardized developmental scales. Consecutive MRS examinations have confirmed that Cr depletion in AGAT-d patients is reversible under Cr supplementation. Cr treatment is considered safe and well tolerated but side effects, including weight gain and kidney stones, have been reported.

CONCLUSIONS

Early treatment prevents adverse developmental outcome, while patients diagnosed and treated at an older age showed partial but significant cognitive recovery with clear improvements in adaptive functioning.

[Prevention and treatment of energy failure in neonates with hypoxic-ischemic encephalopathy]

Hypoxic-ischemic encephalopathy (HIE) in neonates is the brain injury caused by perinatal asphyxia or hypoxia and is a major cause of death in neonates and nervous system dysfunction in infants and young children. Although to a certain degree, mild hypothermia therapy reduces the mortality of infants with moderate to severe HIE, it cannot achieve the expected improvements in nervous system dysfunction. Hence, it is of vital importance to search for effective therapeutic methods for HIE. The search for more therapies and better preventive measures based on the pathogenesis of HIE has resulted in much research. As an important link in the course of HIE, energy failure greatly affects the development and progression of HIE. This article reviews the research advances in the treatment and prevention of energy failure in the course of HIE.

Maternal creatine in pregnancy: a retrospective cohort study

OBJECTIVE

To estimate creatine concentrations in maternal plasma and urine, and establish relationships with maternal characteristics, diet and fetal growth.

DESIGN

Retrospective cohort study.

SETTING

Lyell McEwin Hospital, Adelaide, Australia.

POPULATION

A biobank of plasma and urine samples collected at 13, 18, 30 and 36 weeks' gestation from 287 pregnant women from a prospective cohort of asthmatic and non-asthmatic women.

METHODS

Creatine was measured by enzymatic analysis. Change in creatine over pregnancy was assessed using the Friedman test. Linear mixed models regression was used to determine associations between maternal factors and diet with creatine across pregnancy and between creatine with indices of fetal growth at birth.

MAIN OUTCOME MEASURES

Maternal creatine concentrations, associations between maternal factors and creatine and between creatine and fetal growth parameters.

RESULTS

Maternal smoking, body mass index, asthma and socio-economic status were positively and parity negatively associated with maternal plasma and/or urine creatine. Maternal urine creatine concentration was positively associated with birthweight centile and birth length. After adjustment, each μmol/l increase in maternal urinary creatine was associated with a 1.23 (95% CI 0.44-2.02) unit increase in birthweight centile and a 0.11-cm (95% CI 0.03-0.2) increase in birth length.

CONCLUSIONS

Maternal factors and fetal growth measures are associated with maternal plasma and urine creatine concentrations.

TWEETABLE ABSTRACT

Maternal creatine is altered by pregnancy; fetal growth measures are associated with maternal creatine concentrations.

Creatine for women: a review of the relationship between creatine and the reproductive cycle and female-specific benefits of creatine therapy

The creatine/phosphocreatine/creatine kinase circuit is instrumental in regulating high-energy phosphate metabolism, and the maintenance of cellular energy turnover. The mechanisms by which creatine is able to buffer and regulate cellular energy balance, maintain acid-base balance, and reduce the effects of oxidative stress have led to a large number of studies into the use of creatine supplementation in exercise performance and to treat diseases associated with cellular energy depletion. Some of these studies have identified sex-specific responses to creatine supplementation, as such; there is the perception, that females might be less receptive to the benefits of creatine supplementation and therapy, compared to males. This review will describe the differences in male and female physique and physiology that may account for such differences, and discuss the apparent endocrine modulation of creatine metabolism in females. Hormone-driven changes to endogenous creatine synthesis, creatine transport and creatine kinase expression suggest that significant changes in this cellular energy circuit occur during specific stages of a female's reproductive life, including pregnancy and menopause. Recent studies suggest that creatine supplementation may be highly beneficial for women under certain conditions, such as depression. A greater understanding of these pathways, and the consequences of alterations to creatine bioavailability in females are needed to ensure that creatine is used to full advantage as a dietary supplement to optimize and enhance health outcomes for women.

Dietary creatine supplementation during pregnancy: a study on the effects of creatine supplementation on creatine homeostasis and renal excretory function in spiny mice

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.

Dietary interventions designed to protect the perinatal brain from hypoxic-ischemic encephalopathy--Creatine prophylaxis and the need for multi-organ protection

Birth asphyxia or hypoxia arises from impaired placental gas exchange during labor and remains one of the leading causes of neonatal morbidity and mortality worldwide. It is a condition that can strike in pregnancies that have been uneventful until these final moments, and leads to fundamental loss of cellular energy reserves in the newborn. The cascade of metabolic changes that occurs in the brain at birth as a result of hypoxia can lead to significant damage that evolves over several hours and days, the severity of which can be ameliorated with therapeutic cerebral hypothermia. However, this treatment is only applied to a subset of newborns that meet strict inclusion criteria and is usually administered only in facilities with a high level of medical surveillance. Hence, a number of neuropharmacological interventions have been suggested as adjunct therapies to improve the efficacy of hypothermia, which alone improves survival of the post-hypoxic infant but does not altogether prevent adverse neurological outcomes. In this review we discuss the prospect of using creatine as a dietary supplement during pregnancy and nutritional intervention that can significantly decrease the risk of brain damage in the event of severe oxygen deprivation at birth. Because brain damage can also arise secondarily to compromise of other fetal organs (e.g., heart, diaphragm, kidney), and that compromise of mitochondrial function under hypoxic conditions may be a common mechanism leading to damage of these tissues, we present data suggesting that dietary creatine supplementation during pregnancy may be an effective prophylaxis that can protect the fetus from the multi-organ consequences of severe hypoxia at birth.