Periconceptional nutrition programs development of the cardiovascular system in the fetal sheep

Alteration of the embryonic microenvironment and sex-specific responses of the preimplantation embryo related to a maternal high-fat diet in the rabbit model

The maternal metabolic environment can be detrimental to the health of the offspring. In a previous work, we showed that maternal high-fat (HH) feeding in rabbit induced sex-dependent metabolic adaptation in the fetus and led to metabolic syndrome in adult offspring. As early development representing a critical window of susceptibility, in the present work we aimed to explore the effects of the HH diet on the oocyte, preimplantation embryo and its microenvironment. In oocytes from females on HH diet, transcriptomic analysis revealed a weak modification in the content of transcripts mainly involved in meiosis and translational control. The effect of maternal HH diet on the embryonic microenvironment was investigated by identifying the metabolite composition of uterine and embryonic fluids collected in vivo by biomicroscopy. Metabolomic analysis revealed differences in the HH uterine fluid surrounding the embryo, with increased pyruvate concentration. Within the blastocoelic fluid, metabolomic profiles showed decreased glucose and alanine concentrations. In addition, the blastocyst transcriptome showed under-expression of genes and pathways involved in lipid, glucose and amino acid transport and metabolism, most pronounced in female embryos. This work demonstrates that the maternal HH diet disrupts the in vivo composition of the embryonic microenvironment, where the presence of nutrients is increased. In contrast to this nutrient-rich environment, the embryo presents a decrease in nutrient sensing and metabolism suggesting a potential protective process. In addition, this work identifies a very early sex-specific response to the maternal HH diet, from the blastocyst stage.

Long-term health outcomes of children born to mothers with hyperemesis gravidarum: a systematic review and meta-analysis

OBJECTIVE

Hyperemesis gravidarum is characterized by severe nausea and vomiting in pregnancy, frequently resulting in severe maternal nutritional deficiency. Maternal undernutrition is associated with adverse offspring health outcomes. Whether hyperemesis gravidarum permanently affects offspring health remains unclear. This review aimed to evaluate the effects of maternal hyperemesis gravidarum on offspring health.

DATA SOURCES

MEDLINE and Embase were searched from inception to September 6, 2021.

STUDY ELIGIBILITY CRITERIA

Studies reporting on health at any age beyond the perinatal period of children born to mothers with hyperemesis gravidarum were included.

METHODS

Two reviewers independently selected studies and extracted data. The Newcastle-Ottawa Quality Assessment Scale was used to assess risk of bias. We conducted a narrative synthesis and meta-analysis where possible. In meta-analyses with high heterogeneity (I²>75%), we did not provide a pooled odds ratio.

RESULTS

Nineteen studies were included in this systematic review (n=1,814,785 offspring). Meta-analysis (n=619, 2 studies: 1 among adolescents and 1 among adults) showed that hyperemesis gravidarum was associated with anxiety disorder (odds ratio, 1.74; 95% confidence interval, 1.04-2.91; I², 0%) and sleep problems in offspring (odds ratio, 2.94; 95% confidence interval, 1.25-6.93; I², 0%). Hyperemesis gravidarum was associated with testicular cancer in male offspring aged up to 40 years on meta-analysis (5 studies, n=20,930 offspring), although heterogeneity was observed on the basis of a wide 95% prediction interval (odds ratio, 1.60; 95% confidence interval, 1.07-2.39; I², 0%; 95% prediction interval, 0.83-3.08). All 6 studies reporting on attention deficit (hyperactivity) disorder and autism spectrum disorder reported an increase among children of mothers with hyperemesis gravidarum in comparison with children of unaffected mothers. Meta-analysis showed high heterogeneity, precluding us from reporting a pooled odds ratio. Most studies reporting on cognitive and motor problems found an increase among hyperemesis gravidarum-exposed children. One study investigated brain structure and found smaller cortical volumes and areas among children from hyperemesis gravidarum-affected pregnancies than among those from unaffected pregnancies. Studies evaluating anthropometry and cardiometabolic disease risk of hyperemesis gravidarum-exposed children had inconsistent findings.

CONCLUSION

Our systematic review showed that maternal hyperemesis gravidarum is associated with small increases in adverse health outcomes among children, including neurodevelopmental disorders, mental health disorders, and possibly testicular cancer, although evidence is based on few studies of low quality.

Effects of maternal nutrient restriction during the periconceptional period on placental development in the mouse

Maternal undernutrition has detrimental effects on fetal development and adult health. Total caloric restriction during early pregnancy followed by adequate nutrition for the remainder of gestation, is particularly linked to cardiovascular and metabolic disease risks during adulthood. The placenta is responsible for transport of nutrients from the maternal to fetal circulation, and the efficiency with which it does so can be adjusted to the maternal nutrient supply. There is evidence that placental adaptations to nutrient restriction in early pregnancy may be retained even when adequate nutrition is restored later in pregnancy, leading to a potential mismatch between placental efficiency and maternal nutrient supplies. However, in the mouse, 50% caloric restriction from days 1.5-11.5 of gestation, while temporarily altering placental structure and gene expression, had no significant effect on day 18.5. The periconceptional period, during which oocyte maturation, fertilization, and preimplantation development occur may be especially critical in creating lasting impact on the placenta. Here, mice were subjected to 50% caloric restriction from 3 weeks prior to pregnancy through d11.5, and then placental structure, the expression of key nutrient transporters, and global DNA methylation levels were examined at gestation d18.5. Prior exposure to caloric restriction increased maternal blood space area, but decreased expression of the key System A amino acid transporter Slc38a4 at d18.5. Neither placental and fetal weights, nor placental DNA methylation levels were affected. Thus, total caloric restriction beginning in the periconceptional period does have a lasting impact on placental development in the mouse, but without changing placental efficiency.

The effect of Bertholletia excelsa on body weight, cholestrol, and c-reactive protein: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE(S)

Bertholletia excelsa is a rich herbal source of anti-oxidants and phenols. The goal of this study is to evaluation the effect of bertholletia excelsa nut on body weight, C-reactive protein (CRP) and lipid profile.

METHODS

A literature search was conducted in PubMed, Scopus and Web of sciences databases by two reviewers up to October 2019. Random effect model used to combine results.

RESULTS

Six studies included in analysis with 71 participants. The population was public population. Pooled results showed Bertholletia excelsa have reduction effect on triglyceride weighted mean difference (WMD: -8.23 mg/dl, 95 % CI -15.09, -1.38, I² = 0%), Cholesterol (WMD: -14.31 mg/dl, 95 % CI -23.38, -5.24, I² = 47 %), Low-density lipoprotein (LDL) (WMD: -9.27 mg/dl, 95 % CI -13.48, -5.06, I² = 0%).

CONCLUSION

This study provided an evidence that Bertholletia excelsa nuts have reduction effect on triglyceride, cholesterol, and LDL levels.

Cohort profile: Singapore Preconception Study of Long-Term Maternal and Child Outcomes (S-PRESTO)

The Singapore Preconception Study of Long-Term Maternal and Child Outcomes (S-PRESTO) is a preconception, longitudinal cohort study that aims to study the effects of nutrition, lifestyle, and maternal mood prior to and during pregnancy on the epigenome of the offspring and clinically important outcomes including duration of gestation, fetal growth, metabolic and neural phenotypes in the offspring. Between February 2015 and October 2017, the S-PRESTO study recruited 1039 Chinese, Malay or Indian (or any combinations thereof) women aged 18-45 years and who intended to get pregnant and deliver in Singapore, resulting in 1032 unique participants and 373 children born in the cohort. The participants were followed up for 3 visits during the preconception phase and censored at 12 months of follow up if pregnancy was not achieved (N = 557 censored). Women who successfully conceived (N = 475) were characterised at gestational weeks 6-8, 11-13, 18-21, 24-26, 27-28 and 34-36. Follow up of their index offspring (N = 373 singletons) is on-going at birth, 1, 3 and 6 weeks, 3, 6, 12, 18, 24 and 36 months and beyond. Women are also being followed up post-delivery. Data is collected via interviewer-administered questionnaires, metabolic imaging (magnetic resonance imaging), standardized anthropometric measurements and collection of diverse specimens, i.e. blood, urine, buccal smear, stool, skin tapes, epithelial swabs at numerous timepoints. S-PRESTO has extensive repeated data collected which include genetic and epigenetic sampling from preconception which is unique in mother-offspring epidemiological cohorts. This enables prospective assessment of a wide array of potential determinants of future health outcomes in women from preconception to post-delivery and in their offspring across the earliest development from embryonic stages into early childhood. In addition, the S-PRESTO study draws from the three major Asian ethnic groups that represent 50% of the global population, increasing the relevance of its findings to global efforts to address non-communicable diseases.

Effects of maternal periconceptional undernutrition in sheep on offspring glucose-insulin axis function into adulthood

Maternal periconceptional undernutrition (PCUN) affected fetal pancreatic maturation in late gestation lambs and impaired glucose tolerance in 10-month-old sheep. To examine the importance of the timing of maternal undernutrition around conception, a further cohort was born to PCUN ewes [undernourished for 61 d before conception (PreC), 30 d after conception (PostC), or 61 d before until 30 d after conception (PrePostC)], or normally fed ewes (Control) (n = 15-20/group). We compared glucose tolerance, insulin secretion, and sensitivity at 36 months of age. We also examined protein expression of insulin signalling proteins in muscle from these animals and in muscle from a fetal cohort (132 d of gestation; n = 7-10/group). Adult PostC and PrePostC sheep had higher glucose area under the curve than Controls (P = 0.07 and P = 0.02, respectively), whereas PreC sheep were similar to Controls (P = 0.97). PostC and PrePostC had reduced first-phase insulin secretion compared with Control (P = 0.03 and P = 0.02, respectively). PreC was similar to Control (P = 0.12). Skeletal muscle SLC2A4 protein expression in PostC and PrePostC was increased 19%-58% in fetuses (P = 0.004), but decreased 39%-43% in adult sheep (P = 0.003) compared with Controls. Consistent with this, protein kinase C zeta (PKCζ) protein expression tended to be increased in fetal (P = 0.09) and reduced in adult (P = 0.07) offspring of all PCUN ewes compared with Controls. Maternal PCUN alters several aspects of offspring glucose homeostasis into adulthood. These findings suggest that maternal periconceptional nutrition has a lasting impact on metabolic homeostasis of the offspring.

Impact of in vitro embryo culture and transfer on blood pressure regulation in the adolescent lamb

Nutrition during the periconceptional period influences postnatal cardiovascular health. We determined whether in vitro embryo culture and transfer, which are manipulations of the nutritional environment during the periconceptional period, dysregulate postnatal blood pressure and blood pressure regulatory mechanisms. Embryos were either transferred to an intermediate recipient ewe (ET) or cultured in vitro in the absence (IVC) or presence of human serum (IVCHS) and a methyl donor (IVCHS+M) for 6 days. Basal blood pressure was recorded at 19-20 weeks after birth. Mean arterial pressure (MAP) and heart rate (HR) were measured before and after varying doses of phenylephrine (PE). mRNA expression of signaling molecules involved in blood pressure regulation was measured in the renal artery. Basal MAP did not differ between groups. Baroreflex sensitivity, set point, and upper plateau were also maintained in all groups after PE stimulation. Adrenergic receptors alpha-1A (αAR1A), alpha-1B (αAR1B), and angiotensin II receptor type 1 (AT1R) mRNA expression were not different from controls in the renal artery. These results suggest there is no programmed effect of ET or IVC on basal blood pressure or the baroreflex control mechanisms in adolescence, but future studies are required to determine the impact of ET and IVC on these mechanisms later in the life course when developmental programming effects may be unmasked by age.

Paternal low protein diet and the supplementation of methyl-donors impact fetal growth and placental development in mice

Introduction

Paternal low-protein diet can alter sperm methylation status, fetal growth and program offspring ill-health, however its impact on the placenta remains poorly defined. Here we examine the influence paternal low-protein diet has on fetal and placental development and the additional impact of supplementary methyl-donors on fetoplacental physiology.

Methods

Male C57BL/6J mice were fed a control normal protein diet (NPD; 18% protein), a low-protein diet (LPD; 9% protein) or LPD with methyl-donor supplementation (MD-LPD; choline chloride, betaine, methionine, folic acid, vitamin B12) for a minimum of 8 weeks. Males were mated with 8–11 week old female C57BL/6J mice and fetal and placental tissue collected on embryonic day 17.5.

Results

Paternal LPD was associated with increased fetal weights compared to NPD and MD-LPD with 22% fetuses being above the 90th centile for fetal weight. However, LPD and MD-LPD placental weights were reduced when compared to NPD. Placentas from LPD fathers demonstrated a reduced junctional zone area and reduced free-fatty acid content. MD-LPD placentas did not mirror these finding, demonstrating an increased chorion area, a reduction in junctional-specific glycogen staining and reduced placental Dnmt3bexpression, none of which were apparent in either NPD or LPD placentas.

Discussion

A sub-optimal paternal diet can influence fetal growth and placental development, and dietary methyl-donor supplementation alters placental morphology and gene expression differentially to that observed with LPD alone. Understanding how paternal diet and micro-nutrient supplementation influence placental development is crucial for determining connections between paternal well-being and future offspring health.

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Paternal low protein diet (LPD) increased late gestation fetal weight.

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Supplementing the LPD with methyl donors (MD-LPD) normalised fetal weight.

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Placental weight and morphology are altered by both LPD and MD-LPD.

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Placental metabolite content and gene expression were perturbed by paternal LPD and MD-LPD.

Effects of periconceptional heat stress on primiparous and multiparous daughters of Holstein dairy cows

To meet growing worldwide demands for animal products, animal production will need to increase in capacity and efficiency. Every opportunity to improve animal protein yield should be considered and explored. Developmental programming is one such opportunity that has not yet been thoroughly investigated in farm animal production. While developmental programming can be advantageous for the survival of the offspring, it is often described in conjunction with negative consequences. The known and potential causes and mechanisms are numerous, often stemming from some sort of stress experienced during the prenatal or early postnatal period. One stressor that is particularly concerning for farm animal production is heat stress. Heat stress is known to elicit adaptations associated with developmental programming in several species, but has not been investigated in dairy cattle until recently. Multiple studies have shown that heat stress experienced during the periconceptional period is generally associated with reduced milk production of resulting offspring. This could be the result of adaptations within the pre-ovulatory oocyte or early developing embryo. Interestingly, in a few select comparisons, periconceptional heat stress was associated with greater milk production. This was only observed when dairy cattle calved in the spring, and would therefore be reaching peak milk production in late spring or early summer (in heat stress). This is consistent with the match/mismatch theory associated with developmental programming, where matched prenatal/postnatal environments confer advantageous adaptations and mismatched prenatal/postnatal environments are generally detrimental to the offspring. While these studies are important additions to our growing knowledge of heat stress impacts on dairy cow production, the broader implication of developmental programming requires further investigation.

Methylation-reprogrammed AGTR1 results in increased vasoconstriction by angiotensin II in human umbilical cord vessel following in vitro fertilization-embryo transfer

AIMS

Assisted reproductive technologies (ART) have been widely used to treat infertility, which may impact on fetuses and offspring. This study investigated the effects of in vitro fertilization-embryo transfer (IVF-ET) on angiotensin II (AII)-mediated vasoconstrictions in umbilical cord vein, and explored possible reprogrammed methylation mechanism.

MATERIALS AND METHODS

Human umbilical cords were randomly divided into ordinary pregnancy and IVF-ET pregnancy. Vascular studies with AII as well as its specific receptor antagonists losartan and PD123,319 were conducted. Real-time quantitative PCR, Western blotting, and methylation analysis by bisulfite sequencing were performed with the cord vessel samples.

KEY FINDINGS

In IVF-ET group, the maximal response to AII in umbilical vessels was significantly greater than that in the ordinary pregnancy. Using losartan and PD123,319, angiotensin receptor subtype 1 (AT1R) was found mainly responsible for the enhanced contraction in the umbilical vein of IVF-ET pregnancy. Decreased mRNA expression of DNMT3A was found in umbilical vein of IVF-ET group. Hypomethylation of the AGTR1 gene (gene encoding AT1R) in the umbilical veins of the IVF group was found. The data suggested that the IVF-ET treatments altered AII-mediated vasoconstrictions in umbilical veins, which could be partially attributed to the increased expression of AT1R.

SIGNIFICANCE

The hypo-methylation of the AGTR1 gene caused by IVF-ET might play important roles in altered vasoconstrictions, impacting on cardiovascular systems in the long run.

Reduced fetal vitamin D status by maternal undernutrition during discrete gestational windows in sheep

Placental transport of vitamin D and other nutrients (e.g. amino acids, fats and glucose) to the fetus is sensitive to maternal and fetal nutritional cues. We studied the effect of maternal calorific restriction on fetal vitamin D status and the placental expression of genes for nutrient transport [aromatic T-type amino acid transporter-1 (TAT-1); triglyceride hydrolase/lipoprotein uptake facilitator lipoprotein lipase (LPL)] and vitamin D homeostasis [CYP27B1; vitamin D receptor (VDR)], and their association with markers of fetal cardiovascular function and skeletal muscle growth. Pregnant sheep received 100% total metabolizable energy (ME) requirements (control), 40% total ME requirements peri-implantation [PI40, 1-31 days of gestation (dGA)] or 50% total ME requirements in late gestation (L, 104-127 dGA). Fetal, but not maternal, plasma 25-hydroxy-vitamin D (25OHD) concentration was lower in PI40 and L maternal undernutrition groups (P<0.01) compared with the control group at 0.86 gestation. PI40 group placental CYP27B1 messenger RNA (mRNA) levels were increased (P<0.05) compared with the control group. Across all groups, higher fetal plasma 25OHD concentration was associated with higher skeletal muscle myofibre and capillary density (P<0.05). In the placenta, higher VDR mRNA levels were associated with higher TAT-1 (P<0.05) and LPL (P<0.01) mRNA levels. In the PI40 maternal undernutrition group only, reduced fetal plasma 25OHD concentration may be mediated in part by altered placental CYP27B1. The association between placental mRNA levels of VDR and nutrient transport genes suggests a way in which the placenta may integrate nutritional cues in the face of maternal dietary challenges and alter fetal physiology.

Maternal Caloric Restriction Implemented during the Preconceptional and Pregnancy Period Alters Hypothalamic and Hippocampal Endocannabinoid Levels at Birth and Induces Overweight and Increased Adiposity at Adulthood in Male Rat Offspring

Exposure to inadequate nutritional conditions in critical windows of development has been associated to disturbances on metabolism and behavior in the offspring later in life. The role of the endocannabinoid system, a known regulator of energy expenditure and adaptive behaviors, in the modulation of these processes is unknown. In the present study, we investigated the impact of exposing rat dams to diet restriction (20% less calories than standard diet) during pre-gestational and gestational periods on: (a) neonatal outcomes; (b) endocannabinoid content in hypothalamus, hippocampus and olfactory bulb at birth; (c) metabolism-related parameters; and (d) behavior in adult male offspring. We found that calorie-restricted dams tended to have a reduced litter size, although the offspring showed normal weight at birth. Pups from calorie-restricted dams also exhibited a strong decrease in the levels of anandamide (AEA), 2-arachidonoylglycerol (2-AG), arachidonic acid (AA) and palmitoylethanolamide (PEA) in the hypothalamus at birth. Additionally, pups from diet-restricted dams displayed reduced levels of AEA in the hippocampus without significant differences in the olfactory bulb. Moreover, offspring exhibited increased weight gain, body weight and adiposity in adulthood as well as increased anxiety-related responses. We propose that endocannabinoid signaling is altered by a maternal caloric restriction implemented during the preconceptional and pregnancy periods, which might lead to modifications of the hypothalamic and hippocampal circuits, potentially contributing to the long-term effects found in the adult offspring.

Impact of nutritional programming on the growth, health, and sexual development of bull calves

The growth, health, and reproductive performance of bull calves are important prerequisites for a successful cattle breeding program. Therefore, several attempts have been made to improve these parameters via nutritional programming. Although an increase in energy uptake during the postweaning period (7-8 mo of age) of the calves leads to a faster growing rate, it has no positive effects on sexual development. In contrast, a high-nutrition diet during the prepubertal period (8-20 wk of age) reduced the age at puberty of the bulls and increased the size and/or weight of the testis and the epididymal sperm reserves. This faster sexual development is associated with an increased transient LH peak, which seems to be mediated by an increase in serum IGF-I concentrations. However, the exact mechanisms responsible for the interaction between nutrition and the subsequent development of the calves are not clear. The sexual development of bull calves depends not only on the nutrition of the calves after birth but also on the feed intake of their mothers during pregnancy. In contrast to the effects of the feed intake of the bull calves, a high-nutrition diet fed to the mother during the first trimester has negative effects on the reproductive performance of their offspring. In conclusion, it has been clearly demonstrated that growth, health, and reproductive performance can be improved by nutritional programming, but further studies are necessary to obtain a better understanding about the mechanisms responsible for this phenomenon.

Impact of maternal undernutrition around the time of conception on factors regulating hepatic lipid metabolism and microRNAs in singleton and twin fetuses

We have investigated the effects of embryo number and maternal undernutrition imposed either around the time of conception or before implantation on hepatic lipid metabolism in the sheep fetus. We have demonstrated that periconceptional undernutrition and preimplantation undernutrition each resulted in decreased hepatic fatty acid β-oxidation regulators, PGC-1α (P < 0.05), PDK2 (P < 0.01), and PDK4 (P < 0.01) mRNA expression in singleton and twin fetuses at 135-138 days gestation. In singletons, there was also lower hepatic PDK4 (P < 0.01), CPT-1 (P < 0.01), and PKCζ (P < 0.01) protein abundance in the PCUN and PIUN groups and a lower protein abundance of PDPK-1 (P < 0.05) in the PCUN group. Interestingly, in twins, the hepatic protein abundance of p-AMPK (Ser(485)) (P < 0.01), p-PDPK-1 (Ser(41)) (P < 0.05), and PKCζ (P < 0.05) was higher in the PCUN and PIUN groups, and hepatic PDK4 (P < 0.001) and CPT-1 (P < 0.05) protein abundance was also higher in the PIUN twin fetus. We also found that the expression of a number of microRNAs was altered in response to PCUN or PIUN and that there is evidence that these changes may underlie the changes in the protein abundance of key regulators of hepatic fatty acid β-oxidation in the PCUN and PIUN groups. Therefore, embryo number and the timing of maternal undernutrition in early pregnancy have a differential impact on hepatic microRNA expression and on the factors that regulate hepatic fatty acid oxidation and lipid synthesis.

Programming of Essential Hypertension: What Pediatric Cardiologists Need to Know

Hypertension is recognized as one of the major contributing factors to cardiovascular disease, but its etiology remains incompletely understood. Known genetic and environmental influences can only explain a small part of the variability in cardiovascular disease risk. The missing heritability is currently one of the most important challenges in blood pressure and hypertension genetics. Recently, some promising approaches have emerged that move beyond the DNA sequence and focus on identification of blood pressure genes regulated by epigenetic mechanisms such as DNA methylation, histone modification and microRNAs. This review summarizes information on gene-environmental interactions that lead toward the developmental programming of hypertension with specific reference to epigenetics and provides pediatricians and pediatric cardiologists with a more complete understanding of its pathogenesis.

The periconceptional environment and cardiovascular disease: does in vitro embryo culture and transfer influence cardiovascular development and health?

Assisted Reproductive Technologies (ARTs) have revolutionised reproductive medicine; however, reports assessing the effects of ARTs have raised concerns about the immediate and long-term health outcomes of the children conceived through ARTs. ARTs include manipulations during the periconceptional period, which coincides with an environmentally sensitive period of gamete/embryo development and as such may alter cardiovascular development and health of the offspring in postnatal life. In order to identify the association between ARTs and cardiovascular health outcomes, it is important to understand the events that occur during the periconceptional period and how they are affected by procedures involved in ARTs. This review will highlight the emerging evidence implicating adverse cardiovascular outcomes before and after birth in offspring conceived through ARTs in both human and animal studies. In addition, it will identify the potential underlying causes and molecular mechanisms responsible for the congenital and adult cardiovascular dysfunctions in offspring whom were conceived through ARTs.

Developmental programming of cardiovascular disease following intrauterine growth restriction: findings utilising a rat model of maternal protein restriction

Over recent years, studies have demonstrated links between risk of cardiovascular disease in adulthood and adverse events that occurred very early in life during fetal development. The concept that there are embryonic and fetal adaptive responses to a sub-optimal intrauterine environment often brought about by poor maternal diet that result in permanent adverse consequences to life-long health is consistent with the definition of "programming". The purpose of this review is to provide an overview of the current knowledge of the effects of intrauterine growth restriction (IUGR) on long-term cardiac structure and function, with particular emphasis on the effects of maternal protein restriction. Much of our recent knowledge has been derived from animal models. We review the current literature of one of the most commonly used models of IUGR (maternal protein restriction in rats), in relation to birth weight and postnatal growth, blood pressure and cardiac structure and function. In doing so, we highlight the complexity of developmental programming, with regards to timing, degree of severity of the insult, genotype and the subsequent postnatal phenotype.

Programming of cardiovascular disease across the life-course

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality, affecting both developed and developing countries. Whilst it is well recognized that our risk of CVD can be determined by the interaction between our genetics and lifestyle, this only partly explains the variability at the population level. Based on these well-known risk factors, for many years, intervention and primary prevention strategies have focused on modifying lifestyle factors in adulthood. However, research shows that our risk of CVD can be pre-determined by our early life environment and this area of research is known as the Developmental Origins of Health and Disease. The aim of this review is to evaluate our current understanding of mechanisms underlying the programming of CVD. This article is part of a special issue entitled CV Aging.

Impaired glucose metabolism in response to high fat diet in female mice conceived by in vitro fertilization (IVF) or ovarian stimulation alone

Individuals conceived by in vitro fertilization (IVF) may be at increased risk of cardio-metabolic disorders. We recently reported that IVF conceived male mice displayed impaired glucose metabolism at normal and high body weights. In this study, we examined glucose metabolism in mature female C57BL/6J mice that were conceived by natural conception (NC), by ovarian stimulation (OS) or by IVF following chow or high-fat diet (HFD) for 8 weeks. By design, litter size was comparable between groups, but interestingly the birth weight of IVF and OS females was lower than NC females (p ≤ 0.001). Mature IVF female mice displayed increased fasting glucose as compared to NC and OS mice, irrespective of diet. Mature IVF and OS mice were also more susceptible to the metabolic consequences of high fat diet as compared with NC females, with impaired glucose tolerance (p ≤ 0.01), whereas peripheral insulin resistance and increased hepatic expression of gluconeogenic genes Ppargc1α, Pck1 and G6pc was observed in IVF mice only (p<0.05). This study suggests that ovarian stimulation alone and IVF program distinct metabolic effects in females, but that high fat diet may be required to unmask these effects. This study adds to the growing body of literature that assisted reproduction procedures may increase the risk of developing type 2 diabetes in an obesity prone environment.

Impact of the periconceptional environment on the programming of adult disease

The periconceptional period of mammalian development has been identified as an early 'developmental window' during which environmental conditions may influence the pattern of future growth and physiology. Studies in humans and animal models have revealed that factors such as maternal nutritional status or in vitro culture and manipulation of developing gametes and preimplantation embryos can impact upon the long-term health and physiology of the offspring. However, the mechanisms involved in the programming of adult disease in response to altered periconceptional development require increased investigation. The role of epigenetic modifications to DNA and chromatin organisation has been identified as a likely mechanism through which environmental perturbations can affect gene expression patterns resulting in phenotypic change. This study will highlight the sensitivity of two critical stages in early mammalian development, gametogenesis and preimplantation development. We will detail how changes to the immediate environment can not only impact upon developmental processes taking place at that time, but can also affect long-term aspects of offspring health and physiology. We will also discuss the emerging role of epigenetics as a mechanistic link between the environment and the later phenotype of the developing organism.

Parental diet, pregnancy outcomes and offspring health: metabolic determinants in developing oocytes and embryos

The periconceptional period, embracing the terminal stages of oocyte growth and post-fertilisation development up to implantation, is sensitive to parental nutrition. Deficiencies or excesses in a range of macro- and micronutrients during this period can lead to impairments in fertility, fetal development and long-term offspring health. Obesity and genotype-related differences in regional adiposity are associated with impaired liver function and insulin resistance, and contribute to fatty acid-mediated impairments in sperm viability and oocyte and embryo quality, all of which are associated with endoplasmic reticulum stress and compromised fertility. Disturbances to maternal protein metabolism can elevate ammonium concentrations in reproductive tissues and disturb embryo and fetal development. Associated with this are disturbances to one-carbon metabolism, which can lead to epigenetic modifications to DNA and associated proteins in offspring that are both insulin resistant and hypertensive. Many enzymes involved in epigenetic gene regulation use metabolic cosubstrates (e.g. acetyl CoA and S-adenosyl methionine) to modify DNA and associated proteins, and so act as 'metabolic sensors' providing a link between parental nutritional status and gene regulation. Separate to their genomic contribution, spermatozoa can also influence embryo development via direct interactions with the egg and by seminal plasma components that act on oviductal and uterine tissues.

Maternal undernutrition around the time of conception and embryo number each impact on the abundance of key regulators of cardiac growth and metabolism in the fetal sheep heart

Poor maternal nutrition before and during pregnancy is associated with an increased risk of cardiovascular disease in later life. To determine the impact of maternal undernutrition during the periconceptional (PCUN: -45 days to 6 days) and preimplantation (PIUN: 0-6 days) periods on cardiac growth and metabolism, we have quantified the mRNA and protein abundance of key regulators of cardiac growth and metabolism in the left ventricle of the sheep fetus in late gestation. The cardiac protein abundance of AMP-activated protein kinase (AMPK), phospho-acetyl CoA carboxykinase (ACC) and pyruvate dehydrogenase kinase-4 (PDK-4) were decreased, whereas ACC was increased in singletons in the PCUN and PIUN groups. In twins, however, cardiac ACC was decreased in the PCUN and PIUN groups, and carnitine palmitoyltransferase-1 (CPT-1) was increased in the PIUN group. In singletons, the cardiac abundance of insulin receptor β (IRβ) was decreased in the PCUN group, and phosphoinositide-dependent protein kinase-1 (PDPK-1) was decreased in the PCUN and PIUN groups. In twins, however, the cardiac abundance of IRβ and phospho-Akt substrate 160kDa (pAS160) were increased in the PIUN group. The cardiac abundance of insulin-like growth factor-2 receptor (IGF-2R), protein kinase C alpha (PKCα) and mammalian target of rapamycin (mTOR) were decreased in PCUN and PIUN singletons and extracellular-signal-regulated kinase (ERK) was also decreased in the PIUN singletons. In contrast, in twins, cardiac abundance of IGF-2R and PKCα were increased in the PCUN and PIUN groups, phospho-ribosomal protein S6 (pRPS6) was increased in the PCUN group, and ERK and eukaryotic initiation factor 4E (eIF4E) were also increased in the PIUN fetuses. In conclusion, maternal undernutrition limited to around the time of conception is sufficient to alter the abundance of key factors regulating cardiac growth and metabolism and this may increase the propensity for cardiovascular diseases in later life.

Paternal low protein diet affects adult offspring cardiovascular and metabolic function in mice

Although the association between maternal periconceptional diet and adult offspring health is well characterised, our understanding of the impact of paternal nutrition at the time of conception on offspring phenotype remains poorly defined. Therefore, we determined the effect of a paternal preconception low protein diet (LPD) on adult offspring cardiovascular and metabolic health in mice. Male C57BL/6 mice were fed either normal protein diet (NPD; 18% casein) or LPD (9% casein) for 7 wk before mating. At birth, a reduced male-to-female ratio ( P = 0.03) and increased male offspring weight ( P = 0.009) were observed in litters from LPD compared with NPD stud males with no differences in mean litter size. LPD offspring were heavier than NPD offspring at 2 and 3 wk of age ( P < 0.02). However, no subsequent differences in body weight were observed. Adult male offspring derived from LPD studs developed relative hypotension (decreased by 9.2 mmHg) and elevated heart rate ( P < 0.05), whereas both male and female offspring displayed vascular dysfunction and impaired glucose tolerance relative to NPD offspring. At cull (24 wk), LPD males had elevated adiposity ( P = 0.04), reduced heart-to-body weight ratio ( P = 0.04), and elevated circulating TNF-α levels ( P = 0.015) compared with NPD males. Transcript expression in offspring heart and liver tissue was reduced for genes involved in calcium signaling ( Adcy, Plcb, Prkcb) and metabolism ( Fto) in LPD offspring ( P < 0.03). These novel data reveal the impact of suboptimal paternal nutrition on adult offspring cardiovascular and metabolic homeostasis, and provide some insight into the underlying regulatory mechanisms.

Impact of embryo number and maternal undernutrition around the time of conception on insulin signaling and gluconeogenic factors and microRNAs in the liver of fetal sheep

This study aimed to determine whether exposure of the oocyte and/or embryo to maternal undernutrition results in the later programming of insulin action in the liver and factors regulating gluconeogenesis. To do this, we collect livers from singleton and twin fetal sheep that were exposed to periconceptional (PCUN; -60 to 7 days) or preimplantation (PIUN; 0-7 days) undernutrition at 136-138 days of gestation (term = 150 days). The mRNA and protein abundance of insulin signaling and gluconeogenic factors were then quantified using qRT-PCR and Western blotting, respectively, and global microRNA expression was quantified using deep sequencing methodology. We found that hepatic PEPCK-C mRNA (P < 0.01) and protein abundance and the protein abundance of IRS-1 (P < 0.01), p110β (P < 0.05), PTEN (P < 0.05), CREB (P < 0.01), and pCREB (Ser(133); P < 0.05) were decreased in the PCUN and PIUN singletons. In contrast, hepatic protein abundance of IRS-1 (P < 0.01), p85 (P < 0.01), p110β (P < 0.001), PTEN (P < 0.01), Akt2 (P < 0.01), p-Akt (Ser(473); P < 0.01), and p-FOXO-1 (Thr24) (P < 0.01) was increased in twins. There was a decrease in PEPCK-C mRNA (P < 0.01) but, paradoxically, an increase in PEPCK-C protein (P < 0.001) in twins. Both PCUN and PIUN altered the hepatic expression of 23 specific microRNAs. We propose that the differential impact of maternal undernutrition in the presence of one or two embryos on mRNAs and proteins involved in the insulin signaling and gluconeogenesis is explained by changes in the expression of a suite of specific candidate microRNAs.

Periconception weight loss: common sense for mothers, but what about for babies?

Obesity in the childbearing population is increasingly common. Obesity is associated with increased risk for a number of maternal and neonatal pregnancy complications. Some of these complications, such as gestational diabetes, are risk factors for long-term disease in both mother and baby. While clinical practice guidelines advocate for healthy weight prior to pregnancy, there is not a clear directive for achieving healthy weight before conception. There are known benefits to even moderate weight loss prior to pregnancy, but there are potential adverse effects of restricted nutrition during the periconceptional period. Epidemiological and animal studies point to differences in offspring conceived during a time of maternal nutritional restriction. These include changes in hypothalamic-pituitary-adrenal axis function, body composition, glucose metabolism, and cardiovascular function. The periconceptional period is therefore believed to play an important role in programming offspring physiological function and is sensitive to nutritional insult. This review summarizes the evidence to date for offspring programming as a result of maternal periconception weight loss. Further research is needed in humans to clearly identify benefits and potential risks of losing weight in the months before conceiving. This may then inform us of clinical practice guidelines for optimal approaches to achieving a healthy weight before pregnancy.

Adverse prenatal environment and kidney development: implications for programing of adult disease

The 'developmental origins of health and disease' hypothesis suggests that many adult-onset diseases can be attributed to altered growth and development during early life. Perturbations during gestation can be detrimental and lead to an increased risk of developing renal, cardiovascular, metabolic, and neurocognitive dysfunction in adulthood. The kidney has emerged as being especially vulnerable to insult at almost any stage of development resulting in a reduction in nephron endowment. In both humans and animal models, a reduction in nephron endowment is strongly associated with an increased risk of hypertension. The focus of this review is twofold: i) to determine the importance of specific periods during development on long-term programing and ii) to examine the effects of maternal perturbations on the developing kidney and how this may program adult-onset disease. Recent evidence has suggested that insults occurring around the time of conception also have the capacity to influence long-term health. Although epigenetic mechanisms are implicated in mediating these outcomes, it is unclear as to how these may impact on kidney development. This presents exciting new challenges and areas for research.

Periconceptional undernutrition programs changes in insulin-signaling molecules and microRNAs in skeletal muscle in singleton and twin fetal sheep

Maternal undernutrition around the time of conception is associated with an increased risk of insulin resistance in adulthood. We determined the effect of maternal undernutrition in the periconceptional period (PCUN, i.e., 60 days prior to 6 days after conception) and the preimplantation period (PIUN, i.e., 0-6 days after conception) on mRNA expression and protein abundance of key insulin-signaling molecules as well as the global microRNA expression in quadriceps muscle of singleton and twin fetal sheep in late gestation. In singleton fetuses, exposure to PCUN resulted in lower protein abundance of PIK3CB (P < 0.01), PRKCZ (P < 0.05), and pPRKCZ (Thr410) (P < 0.05) in skeletal muscle compared to controls. In PIUN singletons, there was a higher protein abundance of IRS1 (P < 0.05), PDPK1 (P < 0.05), and SLC2A4 (P < 0.05) compared to controls. In twins, PCUN resulted in higher protein abundance of IRS1 (P < 0.05), AKT2 (P < 0.05), PDPK1 (P < 0.05), and PRKCZ (P < 0.001), while PIUN also resulted in higher protein abundance of IRS1 (P < 0.05), PRKCZ (P < 0.001), and SLC2A4 (P < 0.05) in fetal muscle compared to controls. There were specific patterns of the types and direction of changes in the expression of 22 microRNAs in skeletal muscle after exposure to PCUN or PIUN and clear differences in these patterns between singleton and twin pregnancies. These findings provide evidence that maternal undernutrition around the time of conception induces changes in the expression of microRNAs, which may play a role in altering the abundance of the key insulin-signaling molecules in skeletal muscle and in the association between PCUN undernutrition and insulin resistance in adult life.

Dietary restriction in the periconceptional period in normal-weight or obese ewes results in increased abundance of angiotensin-converting enzyme (ACE) and angiotensin type 1 receptor (AT1R) in the absence of changes in ACE or AT1R methylation in the adrenal of the offspring

Exposure to dietary restriction during the periconceptional period in either normal or obese ewes results in increased adrenal growth and a greater cortisol response to stress in the offspring, but the mechanisms that programme these changes are not fully understood. Activation of the angiotensin type 1 receptor (AT1R) has been demonstrated to stimulate adrenal growth and steroidogenesis. We have used an embryo transfer model in the sheep to investigate the effects of exposure to dietary restriction in normal or obese mothers from before and 1 week after conception on the methylation status, expression, abundance and localisation of key components of the renin–angiotensin system (RAS) in the adrenal of post-natal lambs. Maternal dietary restriction in normal or obese ewes during the periconceptional period resulted in an increase in angiotensin-converting enzyme (ACE) and AT1R abundance in the absence of changes in the methylation status or mRNA expression ofACEandAT1Rin the adrenal of the offspring. Exposure to maternal obesity alone also resulted in an increase in adrenal AT1R abundance. There was no effect of maternal dietary restriction or obesity on ACE2 and AT2R or on ERK, calcium/calmodulin-dependent kinase II abundance, and their phosphorylated forms in the lamb adrenal. Thus, weight loss around the time of conception, in both normal-weight and obese ewes, results in changes within the intra-adrenal RAS consistent with increased AT1R activation. These changes within the intra-adrenal RAS system may contribute to the greater adrenal stress response following exposure to signals of adversity in the periconceptional period.

Impact of embryo number and periconceptional undernutrition on factors regulating adipogenesis, lipogenesis, and metabolism in adipose tissue in the sheep fetus

Maternal undernutrition around the time of conception is associated with an increased risk of insulin resistance in adulthood. We hypothesized that maternal undernutrition during the periconceptional (PCUN: -60 to 7 days) and/or preimplantation (PIUN: 0-7 days) periods would result in a decrease in UCP1 expression and the abundance of insulin signaling molecules and an increase in the abundance of factors that regulate adipogenesis and lipogenesis in fetal perirenal adipose tissue (PAT) and that these effects would be different in singletons and twins. Maternal PCUN and PIUN resulted in a decrease in UCP1 expression in PAT, and PIUN resulted in higher circulating insulin concentrations, an increased abundance of pPKCζ and PDK4, and a decreased abundance of Akt1, phosphorylated mTOR, and PPARγ in PAT in singleton and twin fetuses. In singletons, there was also a decrease in the abundance of p110β in PAT in the PCUN and PIUN groups and an increase in total AMPKα in PAT in the PIUN group. In twins, however, there was an increase in the abundance of mTOR in the PCUN group and an increase in PDK2 and decrease in total AMPKα in the PIUN group. Thus exposure to periconceptional undernutrition programs changes in the thermogenic capacity and the insulin and fatty acid oxidation signaling pathway in visceral fat, and these effects are different in singletons and twins. These findings are important, as the thermogenic capacity of brown fat and the insulin sensitivity of visceral fat are important determinants of the risk of developing obesity and an insulin resistance phenotype in later life.

Biological determinants linking infant weight gain and child obesity: current knowledge and future directions

Childhood obesity rates have reached epidemic proportions. Excessive weight gain in infancy is associated with persistence of elevated weight status and later obesity. In this review, we make the case that weight gain in the first 6 mo is especially predictive of later obesity risk due to the metabolic programming that can occur early postpartum. The current state of knowledge regarding the biological determinants of excess infant weight gain is reviewed, with particular focus on infant feeding choice. Potential mechanisms by which different feeding approaches may program the metabolic profile of the infant, causing the link between early weight gain and later obesity are proposed. These mechanisms are likely highly complex and involve synergistic interactions between endocrine effects and factors that alter the inflammatory and oxidative stress status of the infant. Gaps in current knowledge are highlighted. These include a lack of data describing 1) what type of infant body fat distribution may impart risk and 2) how maternal metabolic dysfunction (obesity and/or diabetes) may affect milk composition and exert downstream effects on infant metabolism. Improved understanding and management of these early postnatal determinants of childhood obesity may have great impact on reducing its prevalence.

Adaptive responses of the embryo to maternal diet and consequences for post-implantation development

Maternal periconceptional (PC) nutrition, coupled with maternal physiological condition, can impact on reproductive performance and potential across mammalian species. Oocyte quality and embryo development are affected adversely by either nutrient restriction or excess. Moreover, the quality of maternal PC nutrition can have lasting effects through fetal development and postnatally into adulthood. Chronic disease, notably cardiovascular and metabolic disease, and abnormal behaviour have been identified in adult offspring in small and large animal models of PC nutrient restriction. These long-term effects associate with compensatory responses that begin from the time of early embryo development. This review assesses the field of PC nutrition in vivo on short- and long-term developmental consequences in rodent and ruminant models and considers the implications for human health.

Maternal periconceptional and gestational low protein diet affects mouse offspring growth, cardiovascular and adipose phenotype at 1 year of age

Human and animal studies have revealed a strong association between periconceptional environmental factors, such as poor maternal diet, and an increased propensity for cardiovascular and metabolic disease in adult offspring. Previously, we reported cardiovascular and physiological effects of maternal low protein diet (LPD) fed during discrete periods of periconceptional development on 6-month-old mouse offspring. Here, we extend the analysis in 1 year aging offspring, evaluating mechanisms regulating growth and adiposity. Isocaloric LPD (9% casein) or normal protein diet (18% casein; NPD) was fed to female MF-1 mice either exclusively during oocyte maturation (for 3.5 days prior to mating; Egg-LPD, Egg-NPD, respectively), throughout gestation (LPD, NPD) or exclusively during preimplantation development (for 3.5 days post mating; Emb-LPD). LPD and Emb-LPD female offspring were significantly lighter and heavier than NPD females respectively for up to 52 weeks. Egg-LPD, LPD and Emb-LPD offspring displayed significantly elevated systolic blood pressure at 52 weeks compared to respective controls (Egg-NPD, NPD). LPD females had significantly reduced inguinal and retroperitoneal fat pad: body weight ratios compared to NPD females. Expression of the insulin receptor (Insr) and insulin-like growth factor I receptor (Igf1r) in retroperitoneal fat was significantly elevated in Emb-LPD females (P<0.05), whilst Emb-LPD males displayed significantly decreased expression of the mitochondrial uncoupling protein 1 (Ucp1) gene compared to NPD offspring. LPD females displayed significantly increased expression of Ucp1 in interscapular brown adipose tissue when compared to NPD offspring. Our results demonstrate that aging offspring body weight, cardiovascular and adiposity homeostasis can be programmed by maternal periconceptional nutrition. These adverse outcomes further exemplify the criticality of dietary behaviour around the time of conception on long-term offspring health.

Maternal obesity and the early origins of childhood obesity: weighing up the benefits and costs of maternal weight loss in the periconceptional period for the offspring

There is a need to understand the separate or interdependent contributions of maternal prepregnancy BMI, gestational weight gain, glycaemic control, and macronutrient intake on the metabolic outcomes for the offspring. Experimental studies highlight that there may be separate influences of maternal obesity during the periconceptional period and late gestation on the adiposity of the offspring. While a period of dietary restriction in obese mothers may ablate the programming of obesity, it is associated with an activation of the stress axis in the offspring. Thus, maternal obesity may result in epigenetic changes which predict the need for efficient fat storage in postnatal life, while maternal weight loss may lead to epigenetic changes which predict later adversity. Thus, development of dietary interventions for obese mothers during the periconceptional period requires a greater evidence base which allows the effective weighing up of the metabolic benefits and costs for the offspring.

Fetal programming and metabolic syndrome

Metabolic syndrome is reaching epidemic proportions, particularly in developing countries. In this review, we explore the concept-based on the developmental-origin-of-health-and-disease hypothesis-that reprogramming during critical times of fetal life can lead to metabolic syndrome in adulthood. Specifically, we summarize the epidemiological evidence linking prenatal stress, manifested by low birth weight, to metabolic syndrome and its individual components. We also review animal studies that suggest potential mechanisms for the long-term effects of fetal reprogramming, including the cellular response to stress and both organ- and hormone-specific alterations induced by stress. Although metabolic syndrome in adulthood is undoubtedly caused by multiple factors, including modifiable behavior, fetal life may provide a critical window in which individuals are predisposed to metabolic syndrome later in life.

Hungry in the womb: what are the consequences? Lessons from the Dutch famine

An increasing body of evidence suggests that poor nutrition at the very beginning of life - even before birth - leads to large and long term negative consequences for both mental and physical health. This paper reviews the evidence from studies on the Dutch famine, which investigated the effects of prenatal undernutrition on later health. The effects of famine appeared to depend on its timing during gestation, and the organs and tissues undergoing critical periods of development at that time. Early gestation appeared to be the most vulnerable period. People who were conceived during the famine were at increased risk of schizophrenia and depression, they had a more atherogenic plasma lipid profile, were more responsive to stress and had a doubled rate of coronary heart disease. Also, they performed worse on cognitive tasks which may be a sign of accelerated ageing. People exposed during any period of gestation had more type 2 diabetes. Future investigation will expand on the finding that the effects of prenatal famine exposure may reach down across generations, possibly through epigenetic mechanisms. Recent evidence suggests that similar effects of prenatal undernutrition are found in Africa, where many are undernourished. Hunger is a major problem worldwide with one in seven inhabitants of this planet suffering from lack of food. Adequately feeding women before and during pregnancy may be a promising strategy in preventing chronic diseases worldwide.

The long-term effects of prenatal development on growth and metabolism

People who were small at birth and had poor infant growth have an increased risk of adult cardiovascular disease, osteoporosis, and type 2 diabetes, particularly if their restricted early growth was followed by increased childhood weight gain. These relations extend across the normal range of birth size in a graded manner, so reduced size is not a prerequisite. In addition, larger birth size is associated with risks of obesity and type 2 diabetes. The associations appear to reflect developmental plastic responses made by the fetus and infant based on cues about the environment, influenced by maternal characteristics including diet, body composition, stress, and exercise levels. These responses involve epigenetic processes that modify the offspring's phenotype. Vulnerability to ill health results if the environment in infancy, childhood, and later life is mismatched to the phenotype induced in development, informed by the developmental cues. This mismatch may arise through unbalanced diet or body composition of the mother or a change in lifestyle factors between generations. These insights offer new possibilities for the early diagnosis and prevention of chronic disease.

Characterization of glucose-insulin responsiveness and impact of fetal number and sex difference on insulin response in the sheep fetus

GSIS is often measured in the sheep fetus by a square-wave hyperglycemic clamp, but maximal β-cell responsiveness and effects of fetal number and sex difference have not been fully evaluated. We determined the dose-response curve for GSIS in fetal sheep (0.9 of gestation) by increasing plasma glucose from euglycemia in a stepwise fashion. The glucose-insulin response was best fit by curvilinear third-order polynomial equations for singletons (y = 0.018x(3) - 0.26x(2) + 1.2x - 0.64) and twins (y = -0.012x(3) + 0.043x(2) + 0.40x - 0.16). In singles, maximal insulin secretion was achieved at 3.4 ± 0.2 mmol/l glucose but began to plateau after 2.4 ± 0.2 mmol/l glucose (90% of maximum), whereas the maximum for twins was reached at 4.8 ± 0.4 mmol/l glucose. In twin (n = 18) and singleton (n = 49) fetuses, GSIS was determined with a square-wave hyperglycemic clamp >2.4 mmol/l glucose. Twins had a lower basal glucose concentration, and plasma insulin concentrations were 59 (P < 0.01) and 43% (P < 0.05) lower in twins than singletons during the euglycemic and hyperglycemic periods, respectively. The basal glucose/insulin ratio was approximately doubled in twins vs. singles (P < 0.001), indicating greater insulin sensitivity. In a separate cohort of fetuses, twins (n = 8) had lower body weight (P < 0.05) and β-cell mass (P < 0.01) than singleton fetuses (n = 7) as a result of smaller pancreata (P < 0.01) and a positive correlation (P < 0.05) between insulin immunopositive area and fetal weight (P < 0.05). No effects of sex difference on GSIS or β-cell mass were observed. These findings indicate that insulin secretion is less responsive to physiological glucose concentrations in twins, due in part to less β-cell mass.

Periconceptional undernutrition and being a twin each alter kidney development in the sheep fetus during early gestation

Adaptive growth responses of the embryo and fetus to nutritional restraint are important in ensuring early survival, but they are implicated in the programming of hypertension. It has been demonstrated that kidney growth and nephrogenesis are each regulated by intrarenal factors, including the insulin-like growth factors, glucocorticoids, and the renin-angiotensin system. Therefore, we have investigated the impact of periconceptional undernutrition (PCUN; from ∼6 wk before to 7 days after conception) in singleton (control, n = 18; PCUN, n = 16) and twin pregnancies (control, n = 6; PCUN, n = 5) on the renal mRNA expression of 11β- hydroxysteroid dehydrogensase type 1 and type 2 (11β-HSD-1 and -2), the glucocorticoid (GR), and mineralocorticoid receptors, angiotensinogen, angiotensin receptor type 1 (AT1R) and 2 (AT2R), IGF-1 and IGF-2, and IGF1R and IGF2R at ∼55 days gestation. There was no effect of PCUN or fetal number on fetal weight on relative kidney weight at approximately day 55 of gestation. There was an inverse relationship between the relative weight of the fetal kidney at approximately day 55 and maternal weight loss during the periconceptional period in fetuses exposed to PCUN. Exposure to PCUN resulted in a higher expression of IGF1 in the fetal kidney in singleton and twin pregnancies. Being a twin resulted in higher intrarenal expression of IGF-1 and IGF-2, GR, angiotensinogen, AT1R, and AT2R mRNA at 55 days gestation. Renal 11β-HSD-2 mRNA expression was higher in PCUN singletons, but not PCUN twins, compared with controls. Thus, there may be an adaptive response in the kidney to the early environment of a twin pregnancy, which precedes the fetal growth restriction that occurs later in pregnancy. The kidney of the twin fetus exposed to periconceptional undernutrition may also be less protected from the consequences of glucocorticoid exposure.

Maternal low-protein diet during mouse pre-implantation development induces vascular dysfunction and altered renin–angiotensin-system homeostasis in the offspring

Environmental perturbations during early mammalian development can affect aspects of offspring growth and cardiovascular health. We have demonstrated previously that maternal gestational dietary protein restriction in mice significantly elevated adult offspring systolic blood pressure. Therefore, the present study investigates the key mechanisms of blood pressure regulation in these mice. Following mating, female MF-1 mice were assigned to either a normal-protein diet (NPD; 18 % casein) or an isocaloric low-protein diet throughout gestation (LPD; 9 % casein), or fed the LPD exclusively during the pre-implantation period (3·5 d) before returning to the NPD for the remainder of gestation (Emb-LPD). All offspring received standard chow. At 22 weeks, isolated mesenteric arteries from LPD and Emb-LPD males displayed significantly attenuated vasodilatation to isoprenaline (P = 0·04 and P = 0·025, respectively), when compared with NPD arteries. At 28 weeks, stereological analysis of glomerular number in female left kidneys revealed no significant difference between the groups. Real-time RT-PCR analysis of type 1a angiotensin II receptor, Na+/K+ ATPase transporter subunits and glucocorticoid receptor expression in male and female left kidneys revealed no significant differences between the groups. LPD females displayed elevated serum angiotensin-converting enzyme (ACE) activity (P = 0·044), whilst Emb-LPD males had elevated lung ACE activity (P = 0·001), when compared with NPD offspring. These data demonstrate that elevated offspring systolic blood pressure following maternal gestational protein undernutrition is associated with impaired arterial vasodilatation in male offspring, elevated serum and lung ACE activity in female and male offspring, respectively, but kidney glomerular number in females and kidney gene expression in male and female offspring appear unaffected.

Effects of pre- and periconceptional undernutrition on arterial function in adult female sheep are vascular bed dependent

The nutritional environment during development and even prior to conception may contribute to cardiovascular risk. In mature adult female sheep, we investigated the effect of preconceptional and periconceptional maternal nutritional restriction on the vascular reactivity of arteries from four vascular beds supplying the heart, thorax, kidney and hindlimb. Welsh Mountain ewes received 100% of nutrient requirements throughout gestation (control group, C, n = 18), or 50% of nutrient requirements for 30 days prior to conception (preconceptional group, PRE, n = 20) or for 15 days either side of conception (periconceptional group, PERI, n = 31) and 100% thereafter. In 3.5-year-old female offspring, the left anterior descending coronary (LAD), left internal thoracic (LITA), right renal and second and third order femoral arteries were dissected and their reactivity was assessed by organ bath or wire myography. Vasoconstrictor responses were greater in both LAD and LITA from PERI offspring compared with C (P < 0.01), while vasoconstriction was unaffected by maternal diet in arteries from the renal and femoral circulations (P = n.s.). Endothelium-dependent and -independent vasodilatation was attenuated in third order femoral arteries of PRE and PERI groups compared with C (P < 0.05). Endothelium-independent vasodilatation was attenuated in both the LAD and renal arteries in the PERI group compared with C (P < 0.05). These data show that moderate maternal undernutrition either prior to or around conception affects vascular function of adult offspring. The effect depends on the timing of the insult, but also on the vascular bed studied and vessel hierarchy in the vascular tree.

Periconceptional undernutrition of ewes impairs glucose tolerance in their adult offspring

Maternal undernutrition throughout pregnancy can have long-term effects on the health of adult offspring. Undernutrition around the time of conception alters growth, metabolism, and endocrinology of the sheep fetus, but the impact on offspring after birth is largely unknown. We determined the effect of maternal periconceptional undernutrition in sheep on glucose tolerance in the offspring before and after puberty. Undernourished (UN) ewes were fed individually to maintain weight loss of 10-15% bodyweight from 61 d before until 30 d after mating. Offspring (24 UN, 30 control) underwent an i.v. glucose tolerance test at 4 and 10 mo of age. Glucose tolerance was similar in both groups at 4 mo. Insulin area under the curve increased by 33% between 4 and 10 mo (101 +/- 8 versus 154 +/- 12 ng x min x mL(-1), p < 0.0001). At 10 mo, UN offspring had a 10% greater glucose area under the curve than controls (809 +/- 22 versus 712 +/- 20 mM x min, p < 0.01), a reduced first phase insulin response (p = 0.003) which was particularly apparent in females and in singletons, and a decreased insulin:glucose ratio (p = 0.01). We conclude that maternal undernutrition around the time of conception results in impaired glucose tolerance in postpubertal offspring.

Blastocyst environment and its influence on offspring cardiovascular health: the heart of the matter

The development of adult-onset diseases such as type II diabetes, obesity and cardiovascular disease is traditionally attributed to adult lifestyle characteristics such as a lack of physical exercise, poor diet and smoking. However, evidence from both human and animal model studies has demonstrated that environmental factors such as an imbalance or reduction in maternal nutrition during gestation can have adverse effects on offspring metabolism and cardiovascular health. The severity and nature of the phenotypic changes induced in offspring is influenced by the period of gestation manipulated. In particular, the mammalian preimplantation embryo in different animal models displays particular sensitivity to environmental factors, either in vivo (maternal diet) or in vitro (embryo culture) that is associated with the onset of cardiovascular dysfunction in adult life. The detailed mechanisms by which environmental conditions can alter postnatal cardiovascular physiology are poorly understood. However, various factors including endothelial function, vascular responsiveness, the renin-angiotensin system, kidney structure and early postnatal growth dynamics have all been recognize as potential contributors. Here, we review the relationship between preimplantation embryo environment and postnatal cardiovascular disease risk, and consider biochemical, molecular, genetic and physiological pathways implicated in this association.