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 [ß: -0.003 µM; 95% confidence interval (CI): -0.07, 0.07; P = 0.94], though urinary creatine declined in late gestation (ß: 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 (ß: -0.38 µM/mmol/L CRN; 95% CI: -0.47, -0.29; P < 0.0001). Urinary GAA followed an opposing pattern (ß: 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 (ß: 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 (ß: -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.

Placenta-Specific Transcripts Containing Androgen Response Elements Are Altered In Silico by Male Growth Outcomes.

A birthweight centile (BWC) below the 25th is associated with an elevated risk of adverse perinatal outcomes, particularly among males. This male vulnerability may stem from alterations in placenta-specific androgen signalling, a signalling axis that involves the androgen receptor (AR)-mediated regulation of target genes containing androgen response elements (AREs). In this study, we examined global and ARE-specific transcriptomic signatures in term male placentae (≥37 weeks of gestation) across BWC subcategories (<10th, 10th-30th, >30th) using RNA-seq and gene set enrichment analysis. ARE-containing transcripts in placentae with BWCs below the 10th percentile were upregulated compared to those in the 10th-30th and >30th percentiles, which coincided with the enrichment of gene sets related to hypoxia and the suppression of gene sets associated with mitochondrial function. In the absence of ARE-containing transcripts in silico, <10th and 10th-30th BWC subcategory placentae upregulated gene sets involved in vasculature development, immune function, and cell adhesion when compared to those in the >30th BWC subcategory. Collectively, our in silico findings suggest that changes in the expression of ARE-containing transcripts in male placentae may contribute to impaired placental vasculature and therefore result in reduced fetal growth outcomes.

Associations between diet quality and dietary patterns and gestational diabetes mellitus in a low-risk cohort of pregnant women in Australia: a cross-sectional study.

INTRODUCTION: Evidence of associations between the Mediterranean Diet Score (MDS) and Dietary Approaches to Stop Hypertension (DASH) score and gestational diabetes mellitus (GDM) in pregnant women is limited. This study examined changes in MDS and DASH and dietary patterns in Australian pregnant women between early and late pregnancy and their associations with GDM. METHODS: The data from n = 284 participants were analysed. Diet quality indices and empirical dietary patterns were determined in early (15 ± 3 weeks gestation) and late pregnancy (35 ± 2 weeks gestation). Paired t-tests were used to examine changes in scores for diet quality indices and dietary patterns from early to late pregnancy. Logistic regression analysis was used to examine associations between GDM, diet quality indices and dietary patterns. RESULTS: Three major dietary patterns were identified at early pregnancy. The first and second dietary patterns included unhealthier and healthier food groups, respectively, and the third comprised mixed food groups. Although diet quality scores did not change over time, consumption of the first dietary pattern increased (p = 0.01), and consumption of the second dietary pattern decreased by late pregnancy in women without GDM (p < 0.001). CONCLUSION: No associations between DASH score, MDS and GDM were found; however an inverse association was observed between the first dietary pattern and GDM in late pregnancy (p = 0.023). Longitudinal studies are needed to examine diet quality and dietary patterns at early and late pregnancy to inform the development of tailored dietary advice for GDM.

Associations of adherence to the DASH diet and Mediterranean diet with maternal c-reactive protein levels during pregnancy.

BACKGROUND AND AIMS: Elevated C-reactive protein (CRP) during pregnancy, a marker of inflammation, is associated with adverse outcomes. Better understanding the relationship between CRP and modifiable factors, including diet, is essential to assist early pregnancy lifestyle interventions. The aim of this study was to assess the relationship between adherence to the Dietary Approaches to Stop Hypertension diet (DASH-diet) and the Mediterranean diet (MED-diet) during pregnancy with maternal plasma CRP in early and late pregnancy. METHODS AND RESULTS: Secondary analysis of the Creatine and Pregnancy Outcomes (CPO) study was undertaken. Women (n = 215) attending antenatal clinics through Monash Health, Melbourne were recruited at 10-20 weeks gestation. Medical history and blood samples were collected at 5 antenatal visits. Adapted DASH-diet and MED-diet scores were calculated from Food Frequency Questionnaires completed at early ([mean ± SD]) (15 ± 3 weeks) and late (36 ± 1 week) pregnancy. CRP was measured in maternal plasma samples collected at the same time points. Adjusted linear regression models assessed associations of early-pregnancy DASH and MED-diet scores with early and late pregnancy plasma CRP. There were no statistically significant changes in DASH-diet score from early (23.5 ± 4.8) to late (23.5 ± 5.2) pregnancy (p = 0.97) or MED-diet score from early (3.99 ± 1.6) to late pregnancy (4.08 ± 1.8) (p = 0.41). At early-pregnancy, there was an inverse relationship between DASH-diet scores and MED-diet scores with plasma CRP; (ß = -0.04 [95%CI = -0.07, -0.00], p = 0.044), (ß = -0.12 [95%CI = -0.21, -0.02], p = 0.023). CONCLUSION: Adherence to the DASH-diet and MED-diet during early pregnancy may be beneficial in reducing inflammation. Assessment of maternal dietary patterns may assist development of preventive strategies, including dietary modification, to optimise maternal cardiometabolic health in pregnancy.

Aspects of human uterine creatine metabolism during the menstrual cycle and at term pregnancy†.

Creatine metabolism likely contributes to energy homeostasis in the human uterus, but whether this organ synthesizes creatine and whether creatine metabolism is adjusted throughout the menstrual cycle and with pregnancy are largely unknown. This study determined endometrial protein expression of creatine-synthesizing enzymes arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT), creatine kinase (CKBB), and the creatine transporter (SLC6A8) throughout the menstrual cycle in fertile and primary infertile women. It also characterized creatine metabolism at term pregnancy, measuring aspects of creatine metabolism in myometrial and decidual tissue. In endometrial samples, AGAT, GAMT, SLC6A8, and CKBB were expressed in glandular and luminal epithelial cells. Except for SLC6A8, the other proteins were also located in stromal cells. Irrespective of fertility, AGAT, GAMT, and SLC6A8 high-intensity immunohistochemical staining was greatest in the early secretory phase of the menstrual cycle. During the proliferative phase, staining for SLC6A8 protein was greater (P = 0.01) in the primary infertile compared with the fertile group. Both layers of the term pregnant uterus contained creatine, phosphocreatine, guanidinoacetic acid, arginine, glycine, and methionine; detectable gene and protein expression of AGAT, GAMT, CKBB, and ubiquitous mitochondrial CK (uMt-CK); and gene expression of SLC6A8. The proteins AGAT, GAMT, CKBB, and SLC6A8 were uniformly distributed in the myometrium and localized to the decidual glands. In conclusion, endometrial tissue has the capacity to produce creatine and its capacity is highest around the time of fertilization and implantation. Both layers of the term pregnant uterus also contained all the enzymatic machinery and substrates of creatine metabolism.

Maternal diet quality and associations with plasma lipid profiles and pregnancy-related cardiometabolic health.

PURPOSE: To assess the relationship of early pregnancy maternal diet quality (DQ) with maternal plasma lipids and indicators of cardiometabolic health, including blood pressure (BP), gestational diabetes mellitus (GDM) and gestational weight gain (GWG). METHODS: Women (n = 215) aged 18-40 years with singleton pregnancies were recruited at 10-20 weeks gestation. Diet quality was assessed by the Dietary Guideline Index, calculated at early ([mean ± SD]) (15 ± 3 weeks) and late (35 ± 2 weeks) pregnancy. Lipidomic analysis was performed, and 698 species across 37 lipid classes were measured from plasma blood samples collected at early (15 ± 3 weeks) and mid (27 ± 3 weeks)-pregnancy. Clinical measures (BP, GDM diagnosis, weight) and blood samples were collected across pregnancy. Multiple linear and logistic regression models assessed associations of early pregnancy DQ with plasma lipids at early and mid-pregnancy, BP at three antenatal visits, GDM diagnosis and total GWG. RESULTS: Maternal DQ scores ([mean ± SD]) decreased significantly from early (70.7 ± 11.4) to late pregnancy (66.5 ± 12.6) (p < 0.0005). At a false discovery rate of 0.2, early pregnancy DQ was significantly associated with 13 plasma lipids at mid-pregnancy, including negative associations with six triglycerides (TGs); TG(54:0)[NL-18:0] (neutral loss), TG(50:1)[NL-14:0], TG(48:0)[NL-18:0], TG(52:1)[NL-18:0], TG(54:1)[NL-18:1], TG(50:0)[NL-18:0]. No statistically significant associations were found between early pregnancy DQ and BP, GDM or GWG. CONCLUSION: Maternal diet did not adhere to Australian Dietary Guidelines. Diet quality was inversely associated with multiple plasma TGs. This study provides novel insights into the relationship between DQ, lipid biomarkers and cardiometabolic health during pregnancy.

Creatine in the fetal brain: A regional investigation of acute global hypoxia and creatine supplementation in a translational fetal sheep model.

Background: Creatine supplementation during pregnancy is a promising prophylactic treatment for perinatal hypoxic brain injury. Previously, in near-term sheep we have shown that fetal creatine supplementation reduces cerebral metabolic and oxidative stress induced by acute global hypoxia. This study investigated the effects of acute hypoxia with or without fetal creatine supplementation on neuropathology in multiple brain regions. Methods: Near-term fetal sheep were administered continuous intravenous infusion of either creatine (6 mg kg-1 h-1) or isovolumetric saline from 122 to 134 days gestational age (dGA; term is approx. 145 dGA). At 131 dGA, global hypoxia was induced by a 10 min umbilical cord occlusion (UCO). Fetuses were then recovered for 72 h at which time (134 dGA) cerebral tissue was collected for either RT-qPCR or immunohistochemistry analyses. Results: UCO resulted in mild injury to the cortical gray matter, thalamus and hippocampus, with increased cell death and astrogliosis and downregulation of genes involved in regulating injury responses, vasculature development and mitochondrial integrity. Creatine supplementation reduced astrogliosis within the corpus callosum but did not ameliorate any other gene expression or histopathological changes induced by hypoxia. Of importance, effects of creatine supplementation on gene expression irrespective of hypoxia, including increased expression of anti-apoptotic (BCL-2) and pro-inflammatory (e.g., MPO, TNFa, IL-6, IL-1ß) genes, particularly in the gray matter, hippocampus, and striatum were identified. Creatine treatment also effected oligodendrocyte maturation and myelination in white matter regions. Conclusion: While supplementation did not rescue mild neuropathology caused by UCO, creatine did result in gene expression changes that may influence in utero cerebral development.

Maternal plasma vitamin D levels across pregnancy are not associated with neonatal birthweight: findings from an Australian cohort study of low-risk pregnant women.

BACKGROUND: In utero environments can be highly influential in contributing to the development of offspring obesity. Specifically, vitamin D deficiency during pregnancy is associated with adverse maternal and child health outcomes, however its relationship with offspring obesity remains unclear. We assessed maternal vitamin D status across pregnancy, change in plasma vitamin D concentrations and associations with neonatal birthweight, macrosomia and large for gestational age. METHODS: Women (n = 221) aged 18-40 years with singleton (low-risk) pregnancies, attending antenatal clinics at a tertiary-level maternity hospital were recruited at 10-20 weeks gestation. Medical history, maternal weight and blood samples at three antenatal clinic visits were assessed; early (15 ± 3 weeks), mid (27 ± 2 weeks) and late (36 ± 1 weeks) gestation. Maternal 25(OH)D was analysed from stored plasma samples via liquid chromatography-tandem mass spectrometry (LC/MS/MS). Neonatal growth parameters were collected at birth. Unadjusted and adjusted linear and logistic regression assessed associations of maternal vitamin D with birthweight, macrosomia and large for gestational age. RESULTS: Mean plasma 25(OH)D increased from early (83.8 ± 22.6 nmol/L) to mid (96.5 ± 28.9 nmol/L) and late (100.8 ± 30.8 nmol/L) gestation. Overall 98% of women were taking vitamin D-containing supplements throughout their pregnancy. Prevalence of vitamin D deficiency (25(OH)D < 50 nmol/L) was 6.5%, 6.3% and 6.8% at early, mid and late pregnancy respectively. No statistically significant association was found between 25(OH)D or vitamin D deficiency at any timepoint with neonatal birthweight, macrosomia or large for gestational age. CONCLUSIONS: Prevalence of vitamin D deficiency was low in this cohort of pregnant women and likely related to the high proportion of women taking vitamin D supplements during pregnancy. Maternal 25(OH)D did not impact offspring birth weight or birth size. Future studies in high-risk pregnant populations are needed to further assess maternal vitamin D status and factors in utero which promote early life obesity.

Creatine supplementation reduces the cerebral oxidative and metabolic stress responses to acute in utero hypoxia in the late-gestation fetal sheep.

Prophylactic creatine treatment may reduce hypoxic brain injury due to its ability to sustain intracellular ATP levels thereby reducing oxidative and metabolic stress responses during oxygen deprivation. Using microdialysis, we investigated the real-time in vivo effects of fetal creatine supplementation on cerebral metabolism following acute in utero hypoxia caused by umbilical cord occlusion (UCO). Fetal sheep (118 days' gestational age (dGA)) were implanted with an inflatable Silastic cuff around the umbilical cord and a microdialysis probe inserted into the right cerebral hemisphere for interstitial fluid sampling. Creatine (6 mg kg-1  h-1 ) or saline was continuously infused intravenously from 122 dGA. At 131 dGA, a 10 min UCO was induced. Hourly microdialysis samples were obtained from -24 to 72 h post-UCO and analysed for percentage change of hydroxyl radicals (• OH) and interstitial metabolites (lactate, pyruvate, glutamate, glycerol, glycine). Histochemical markers of protein and lipid oxidation were assessed at post-mortem 72 h post-UCO. Prior to UCO, creatine treatment reduced pyruvate and glycerol concentrations in the microdialysate outflow. Creatine treatment reduced interstitial cerebral • OH outflow 0 to 24 h post-UCO. Fetuses with higher arterial creatine concentrations before UCO presented with reduced levels of hypoxaemia ( PO2${P_{{{\rm{O}}_{\rm{2}}}}}$ and SO2${S_{{{\rm{O}}_{\rm{2}}}}}$ ) during UCO which associated with reduced interstitial cerebral pyruvate, lactate and • OH accumulation. No effects of creatine treatment on immunohistochemical markers of oxidative stress were found. In conclusion, fetal creatine treatment decreased cerebral outflow of • OH and was associated with an improvement in cerebral bioenergetics following acute hypoxia. KEY POINTS: Fetal hypoxia can cause persistent metabolic and oxidative stress responses that disturb energy homeostasis in the brain. Creatine in its phosphorylated form is an endogenous phosphagen; therefore, supplementation is a proposed prophylactic treatment for fetal hypoxia. Fetal sheep instrumented with a cerebral microdialysis probe were continuously infused with or without creatine-monohydrate for 10 days before induction of 10 min umbilical cord occlusion (UCO; 131 days' gestation). Cerebral interstitial fluid was collected up to 72 h following UCO. Prior to UCO, fetal creatine supplementation reduced interstitial cerebral pyruvate and glycerol concentrations. Fetal creatine supplementation reduced cerebral hydroxyl radical efflux up to 24 h post-UCO. Fetuses with higher arterial creatine concentrations before UCO and reduced levels of systemic hypoxaemia during UCO were associated with reduced cerebral interstitial pyruvate, lactate and • OH following UCO. Creatine supplementation leads to some improvements in cerebral bioenergetics following in utero acute hypoxia.

Influence of Maternal Region of Birth on Placental Pathology of Babies Born Small.

BACKGROUND: Placental pathology is a common antecedent factor in infants born small for gestational age. Maternal region of birth can influence rates of SGA. AIMS: To determine the association of maternal region of birth on placental pathology in babies that are born small, comparing a South Asian born population with Australia and New Zealand born women. MATERIALS AND METHODS: A retrospective cohort study was conducted at Monash Health, the largest public health service in Victoria. Mother-baby pairs above 34 weeks' gestation and birth weight less than 10th centile born in 2016 were included. Placental pathology reports and medical records were reviewed. Statistical analyses of placental and selected neonatal outcomes data were performed. RESULTS: Three hundred and eleven small for gestational age babies were included in this study, of which 171 were born to South Asian mothers and 140 to Australian and New Zealand mothers. There were no significant differences in gestational age at birth between the groups (38.7 (1.6) vs. 38.3 (1.7) weeks, p = 0.06). Placental pathology (macroscopic and microscopic) data comparisons showed no significant differences between the two groups (81% major abnormality in both groups). This was despite South Asian small for gestational age babies being less likely to require admission to a special care nursery or neonatal intensive care unit (35 vs. 41%, p = 0.05), or have a major congenital abnormality (2.3 vs. 4.3%, p = 0.04). CONCLUSION: In this observational study, maternal region of birth did not have an influence on placental pathology of babies born small, despite some differences in neonatal outcomes.

Intrauterine inflammation exacerbates maladaptive remodeling of the immature myocardium after preterm birth in lambs.

BACKGROUND: Antenatal conditions that are linked with preterm birth, such as intrauterine inflammation, can influence fetal cardiac development thereby rendering the heart more vulnerable to the effects of prematurity. We aimed to investigate the effect of intrauterine inflammation, consequent to lipopolysaccharide exposure, on postnatal cardiac growth and maturation in preterm lambs. METHODS: Preterm lambs (~129 days gestational age) exposed antenatally to lipopolysaccharide or saline were managed according to contemporary neonatal care and studied at postnatal day 7. Age-matched fetal controls were studied at ~136 days gestational age. Cardiac tissue was sampled for molecular analyses and assessment of cardiac structure and cardiomyocyte maturation. RESULTS: Lambs delivered preterm showed distinct ventricular differences in cardiomyocyte growth and maturation trajectories as well as remodeling of the left ventricular myocardium compared to fetal controls. Antenatal exposure to lipopolysaccharide resulted in further collagen deposition in the left ventricle and a greater presence of immune cells in the preterm heart. CONCLUSIONS: Adverse impacts of preterm birth on cardiac structure and cardiomyocyte growth kinetics within the first week of postnatal life are exacerbated by intrauterine inflammation. The maladaptive remodeling of the cardiac structure and perturbed cardiomyocyte growth likely contribute to the increased vulnerability to cardiac dysfunction following preterm birth. IMPACT: Preterm birth induces maladaptive cardiac remodeling and adversely impacts cardiomyocyte growth kinetics within the first week of life in sheep. These effects of prematurity on the heart are exacerbated when preterm birth is preceded by exposure to intrauterine inflammation, a common antecedent of preterm birth. Inflammatory injury to the fetal heart coupled with preterm birth consequently alters neonatal cardiac growth and maturation and thus, may potentially influence long-term cardiac function and health.

The Effects of In Utero Fetal Hypoxia and Creatine Treatment on Mitochondrial Function in the Late Gestation Fetal Sheep Brain.

Near-term acute hypoxia in utero can result in significant fetal brain injury, with some brain regions more vulnerable than others. As mitochondrial dysfunction is an underlying feature of the injury cascade following hypoxia, this study is aimed at characterizing mitochondrial function at a region-specific level in the near-term fetal brain after a period of acute hypoxia. We hypothesized that regional differences in mitochondrial function would be evident, and that prophylactic creatine treatment would mitigate mitochondrial dysfunction following hypoxia; thereby reducing fetal brain injury. Pregnant Border-Leicester/Merino ewes with singleton fetuses were surgically instrumented at 118 days of gestation (dGa; term is ~145 dGA). A continuous infusion of either creatine (n = 15; 6 mg/kg/h) or isovolumetric saline (n = 16; 1.5 ml/kg/h) was administered to the fetuses from 121 dGa. After 10 days of infusion, a subset of fetuses (8 saline-, 7 creatine-treated) were subjected to 10 minutes of umbilical cord occlusion (UCO) to induce a mild global fetal hypoxia. At 72 hours after UCO, the fetal brain was collected for high-resolution mitochondrial respirometry and molecular and histological analyses. The results show that the transient UCO-induced acute hypoxia impaired mitochondrial function in the hippocampus and the periventricular white matter and increased the incidence of cell death in the hippocampus. Creatine treatment did not rectify the changes in mitochondrial respiration associated with hypoxia, but there was a negative relationship between cell death and creatine content following treatment. Irrespective of UCO, creatine increased the proportion of cytochrome c bound to the inner mitochondrial membrane, upregulated the mRNA expression of the antiapoptotic gene Bcl2, and of PCG1-α, a driver of mitogenesis, in the hippocampus. We conclude that creatine treatment prior to brief, acute hypoxia does not fundamentally modify mitochondrial respiratory function, but may improve mitochondrial structural integrity and potentially increase mitogenesis and activity of antiapoptotic pathways.

Novel Lipidomic Signature Associated With Metabolic Risk in Women With and Without Polycystic Ovary Syndrome.

CONTEXT: Dyslipidemia is a feature of polycystic ovary syndrome (PCOS) and may augment metabolic dysfunction in this population. OBJECTIVE: Using comprehensive lipidomic profiling and gold-standard metabolic measures, we examined whether distinct lipid biomarkers were associated with metabolic risk in women with and without PCOS. METHODS: Using preexisting data and biobanked samples from 76 women (n = 42 with PCOS), we profiled > 700 lipid species by mass spectrometry. Lipids were compared between women with and without PCOS and correlated with direct measures of adiposity (dual x-ray absorptiometry and computed tomography) and insulin sensitivity (hyperinsulinemic-euglycemic clamp), as well as fasting insulin, HbA1c, and hormonal parameters (luteinizing and follicle-stimulating hormones; total and free testosterone; sex hormone-binding globulin [SHBG]; and free androgen index [FAI]). Multivariable linear regression was used with correction for multiple testing. RESULTS: Despite finding no differences by PCOS status, lysophosphatidylinositol (LPI) species esterified with an 18:0 fatty acid were the strongest lipid species associated with all the metabolic risk factors measured in women with and without PCOS. Across the cohort, higher concentrations of LPI(18:0) and lower concentrations of lipids containing docosahexaenoic acid (DHA, 22:6) n-3 polyunsaturated fatty acids were associated with higher adiposity, insulin resistance, fasting insulin, HbA1c and FAI, and lower SHBG. CONCLUSION: Our data indicate that a distinct lipidomic signature comprising high LPI(18:0) and low DHA-containing lipids are associated with key metabolic risk factors that cluster in PCOS, independent of PCOS status. Prospective studies are needed to corroborate these findings in larger cohorts of women with varying PCOS phenotypes.

Assessing Creatine Supplementation for Neuroprotection against Perinatal Hypoxic-Ischaemic Encephalopathy: A Systematic Review of Perinatal and Adult Pre-Clinical Studies.

There is an important unmet need to develop interventions that improve outcomes of hypoxic-ischaemic encephalopathy (HIE). Creatine has emerged as a promising neuroprotective agent. Our objective was to systematically evaluate the preclinical animal studies that used creatine for perinatal neuroprotection, and to identify knowledge gaps that need to be addressed before creatine can be considered for pragmatic clinical trials for HIE. METHODS: We reviewed preclinical studies up to 20 September 2021 using PubMed, EMBASE and OVID MEDLINE databases. The SYRCLE risk of bias assessment tool was utilized. RESULTS: Seventeen studies were identified. Dietary creatine was the most common administration route. Cerebral creatine loading was age-dependent with near term/term-equivalent studies reporting higher increases in creatine/phosphocreatine compared to adolescent-adult equivalent studies. Most studies did not control for sex, study long-term histological and functional outcomes, or test creatine post-HI. None of the perinatal studies that suggested benefit directly controlled core body temperature (a known confounder) and many did not clearly state controlling for potential study bias. CONCLUSION: Creatine is a promising neuroprotective intervention for HIE. However, this systematic review reveals key knowledge gaps and improvements to preclinical studies that must be addressed before creatine can be trailed for neuroprotection of the human fetus/neonate.

The physiological effects of creatine supplementation in fetal sheep before, during, and after umbilical cord occlusion and global hypoxia.

The aim of this study was to investigate the effects of direct creatine infusion on fetal systemic metabolic and cardiovascular responses to mild acute in utero hypoxia. Pregnant ewes (n = 28) were surgically instrumented at 118 days gestation (dGa). A constant intravenous infusion of creatine (6 mg·kg-1·h-1) or isovolumetric saline (1.5 mL·h-1) began at 121 dGa. After 10 days, fetuses were subjected to 10-min umbilical cord occlusion (UCO) to induce mild global hypoxia (saline-UCO, n = 8; creatine-UCO, n = 7) or sham UCO (saline-control, n = 6; creatine-control, n = 7). Cardiovascular, arterial blood gases and metabolites, and plasma creatine were monitored before, during, and then for 72 h following the UCO. Total creatine content in discrete fetal brain regions was also measured. Fetal creatine infusion increased plasma concentrations fivefold but had no significant effects on any measurement pre-UCO. Creatine did not alter fetal physiology during the UCO or in the early recovery stage, up to 24 h after UCO. During the late recovery stage, 24-72 h after UCO, there was a significant reduction in the arterial oxygen pressure and saturation in creatine fetuses (PUCO × TREATMENT = 0.02 and 0.04, respectively). At 72 h after UCO, significant creatine loading was detected in cortical gray matter, hippocampus, thalamus, and striatum (PTREATMENT = 0.01-0.001). In the striatum, the UCO itself increased total creatine content (PUCO = 0.019). Overall, fetal creatine supplementation may alter oxygen flux following an acute hypoxic insult. Increasing total creatine content in the striatum may also be a fetal adaptation to acute oxygen deprivation.NEW & NOTEWORTHY Direct fetal creatine supplementation increased plasma and cerebral creatine concentrations but did not alter fetal body weight, basal cardiovascular output, or blood chemistry. Creatine-treated fetuses displayed changes to arterial oxygenation 24-72 h after acute global hypoxia. An increase in striatum total creatine levels following UCO was also noted and suggests that increasing creatine tissue availability may be an adaptive response against the effects of hypoxia.

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.

Creatine metabolism in the uterus: potential implications for reproductive biology.

Creatine is an amino acid derivative synthesized from arginine, glycine and methionine. It serves as the substrate for the creatine kinase system, which is vital for maintaining ATP levels in tissues with high and fluctuating energy demand. There exists evidence that the creatine kinase system operates in both the endometrial and myometrial layers of the uterus. While use and regulation of this system in the uterus are not well understood, it is likely to be important given uterine tissues undergo phases of increased energy demand during certain stages of the female reproductive cycle, pregnancy, and parturition. This review discusses known adaptations of creatine metabolism in the uterus during the reproductive cycle (both estrous and menstrual), pregnancy and parturition, highlighting possible links to fertility and the existing knowledge gaps. Specifically, we discuss the adaptations and regulation of uterine creatine metabolite levels, cell creatine transport, de novo creatine synthesis, and creatine kinase expression in the various layers and cell types of the uterus. Finally, we discuss the effects of dietary creatine on uterine metabolism. In summary, there is growing evidence that creatine metabolism is up-regulated in uterine tissues during phases where energy demand is increased. While it remains unclear how important these adaptations are in the maintenance of healthy uterine function, furthering our understanding of uterine creatine metabolism may uncover strategies to combat poor embryo implantation and failure to conceive, as well as enhancing uterine contractile performance during labor.

Relationships between Total, Free and Bioavailable Vitamin D and Vitamin D Binding Protein in Early Pregnancy with Neonatal Outcomes: A Retrospective Cohort Study.

Maternal vitamin D deficiency has been associated with adverse neonatal outcomes, however, existing results are inconsistent. Current data focus on total 25-hydroxyvitamin D (25(OH)D) as the common measure of vitamin D status, while additional measures including vitamin D-binding protein (VDBP) and free and bioavailable metabolites have not been explored in relation to neonatal outcomes. We examined whether VDBP and total, free, and bioavailable vitamin D metabolites in early pregnancy are associated with subsequent neonatal outcomes. In this retrospective analysis of 304 women in early pregnancy (<20 weeks gestation), demographic and anthropometric data were collected and total 25(OH)D (chemiluminescent assay), VDBP (polyclonal enzyme-linked immunosorbent assay (ELISA)) and albumin (automated colorimetry) were measured in bio-banked samples. Free and bioavailable 25(OH)D were calculated using validated formulae. Neonatal outcomes were derived from a medical record database. Higher maternal total and free 25(OH)D concentrations were associated with higher neonatal birthweight (ß = 5.05, p = 0.002 and ß = 18.06, p = 0.02, respectively), including after adjustment for maternal covariates including age, body mass index (BMI) and ethnicity (all p ≤ 0.04). Higher total 25(OH)D and VDBP concentrations were associated with a lower likelihood of neonatal jaundice (odds ratio [OR] [95%CI] = 0.997 [0.994, 1.000], p = 0.04 and 0.98 [0.96, 0.99], p = 0.03, respectively), but these were attenuated after adjustment for the above maternal covariates (both p = 0.09). Our findings suggest a novel association between free 25(OH)D and neonatal birthweight. Total 25(OH)D concentrations were also associated with birthweight, and both total 25(OH)D and VDBP were associated with jaundice, but the latter were not significant after adjustment. These results suggest a potential link between these metabolites and neonatal outcomes; however, further large-scale prospective studies are warranted.

Early Pregnancy Vitamin D Binding Protein Is Independently Associated with the Development of Gestational Diabetes: A Retrospective Cohort Study.

BACKGROUND: Vitamin D-binding protein (VDBP) has been implicated in several adverse pregnancy outcomes either directly or indirectly via influencing the concentrations of biologically active vitamin D metabolites. However, human studies exploring these metabolites in pregnancy remain sparse. Here, we examine whether VDBP and total, free, and bioavailable 25-hydroxyvitamin D (25(OH)D) metabolites in early pregnancy are associated with subsequent adverse pregnancy outcomes. METHODS: We conducted a retrospective analysis of 304 pregnant women in early pregnancy (<20 weeks gestation). The demographic characteristics, anthropometric data, and total 25(OH)D were measured and plasma or serum samples were collected and bio-banked. Using these samples, we measured VDBP (polyclonal ELISA) and albumin (automated colorimetry), and calculated free and bioavailable 25(OH)D using validated formulae. Pregnancy outcomes were derived from scanned medical records. Regression models were used to analyse the relationships between vitamin D metabolites in early pregnancy and subsequent pregnancy outcomes (gestational diabetes mellitus (GDM), pre-eclampsia, preterm birth), with adjustment for predetermined clinically relevant maternal factors including age, body mass index (BMI), and ethnicity. RESULTS: Lower VDBP concentrations were associated with higher glucose levels and a greater likelihood of developing GDM at 26-28 weeks gestation (odds ratio [OR] (95% CI) = 0.98 (0.97,0.99), p = 0.015). This finding remained significant after adjustment for maternal covariates including age, BMI, and ethnicity (ß = -0.003, p = 0.03). Lower total, free and bioavailable 25(OH)D, but not VDBP, were associated with a shorter length of gestation, but only the relationship with total 25(OH)D remained significant after adjustment for the above maternal covariates (ß = 0.02, p = 0.006). CONCLUSIONS: This is the first study to examine VDBP, and total, free and bioavailable 25(OH)D in relation to pregnancy outcomes in a well characterised multi-ethnic cohort of pregnant women. Our findings show that VDBP and total 25(OH)D are associated with GDM and length of gestation, respectively; however, further investigations using large-scale prospective studies are needed to confirm our findings.

Risk of Adverse Outcomes in Females Taking Oral Creatine Monohydrate: A Systematic Review and Meta-Analysis.

Creatine Monohydrate (CrM) is a dietary supplement routinely used as an ergogenic aid for sport and training, and as a potential therapeutic aid to augment different disease processes. Despite its increased use in recent years, studies reporting potential adverse outcomes of CrM have been mostly derived from male or mixed sex populations. A systematic search was conducted, which included female participants on CrM, where adverse outcomes were reported, with meta-analysis performed where appropriate. Six hundred and fifty-six studies were identified where creatine supplementation was the primary intervention; fifty-eight were female only studies (9%). Twenty-nine studies monitored for adverse outcomes, with 951 participants. There were no deaths or serious adverse outcomes reported. There were no significant differences in total adverse events, (risk ratio (RR) 1.24 (95% CI 0.51, 2.98)), gastrointestinal events, (RR 1.09 (95% CI 0.53, 2.24)), or weight gain, (mean difference (MD) 1.24 kg pre-intervention, (95% CI -0.34, 2.82)) to 1.37 kg post-intervention (95% CI -0.50, 3.23)), in CrM supplemented females, when stratified by dosing regimen and subject to meta-analysis. No statistically significant difference was reported in measures of renal or hepatic function. In conclusion, mortality and serious adverse events are not associated with CrM supplementation in females. Nor does the use of creatine supplementation increase the risk of total adverse outcomes, weight gain or renal and hepatic complications in females. However, all future studies of creatine supplementation in females should consider surveillance and comprehensive reporting of adverse outcomes to better inform participants and health professionals involved in future trials.