Diet before and during Pregnancy and Offspring Health: The Importance of Animal Models and What Can Be Learned from Them

Diet and physical activity in pregnancy and offspring's cardiovascular health: a systematic review

There is increasing evidence linking maternal diet and physical activity before and during pregnancy with offspring's cardiovascular health. Although many studies examined this association, the evidence has not been reviewed systematically. We therefore undertook a systematic review to synthesize evidence examining the association of maternal diet and physical activity before and during pregnancy with offspring's blood pressure and vascular health. We systematically searched the databases MEDLINE and EMBASE from inception to June 30, 2017. Eligibility screening, data extraction and quality assessment were performed by two independent reviewers. A total of 19 articles were included comprising three randomized controlled trials and 16 observational studies. Of the studies that examined the association of interest, 60% (three out of five studies) showed that high maternal carbohydrate intake was associated with higher offspring's blood pressure. Maternal protein intake during pregnancy was negatively associated with offspring carotid intima-media thickness in two out of two studies. No consistent findings for maternal fatty acid intake were found. There were too few studies to draw conclusions on energy intake, fibre intake, protein/carbohydrate ratio, specific foods, dietary patterns and maternal physical activity. Heterogeneity in exposure and outcome assessment hampered pooling. Also, owing to the observational nature of most studies, causality cannot be established. Harmonization of valid exposure and outcome measurements, and the development of core outcome sets are needed to enable more robust conclusions.

Nutrition during pregnancy and early development (NuPED) in urban South Africa: a study protocol for a prospective cohort

BACKGROUND

Adequate nutrition during pregnancy is important to ensure optimal birth outcomes, maternal health and offspring development. However, little is known about the dietary intake and nutritional status of pregnant women residing in urban South Africa. Therefore, the Nutrition during Pregnancy and Early Development (NuPED) cohort study was initiated to assess early nutrition-related exposures predictive of early childhood development in urban South Africa.

METHODS

The aims of this prospective cohort study are: 1) to assess dietary intake and nutritional status of urban pregnant women in Johannesburg, South Africa, and 2) to determine associations with birth outcomes, measures of maternal health, as well as measures of offspring health and development. Pregnant women (< 18 weeks' gestation) (n = 250) are being recruited from primary healthcare clinics in Johannesburg and are followed-up at a provincial hospital. Participants' dietary intake and nutrient status (focus on micronutrients and fatty acids) are assessed at < 18, 22 and 36 weeks' gestation. Additional assessments during pregnancy include anthropometric and blood pressure measurements, obstetric ultrasound screens, and assessments of food security, maternal fatigue, prenatal depression, allergy, immune function, morbidity and gestational diabetes. At birth, maternal and neonatal health is assessed and an umbilical cord blood sample collected. Maternal and offspring health is followed-up at 6 weeks, as well as at 6, ≈7.5 and 12 months after birth. Follow-up assessments of mothers include anthropometric measures, diet history, nutrient status, blood pressure, breast milk composition, and measures of postnatal depression and fatigue. Follow-up assessments of the offspring include feeding practices, nutrient status, measures of growth, psychomotor, socio-emotional and immune development, morbidity, allergy, as well as analysis of the gut microbiome and the epigenome.

DISCUSSION

Ensuring adequate nutrition during pregnancy is one of the key actions endorsed by the South African Government to promote optimal early childhood development in an effort to eradicate poverty. The results from this study may serve as a basis for the development of context-specific nutritional interventions which can improve birth outcomes and long-term quality of life of the mother and her offspring.

Review shows that maternal obesity induces serious adverse neonatal effects and is associated with childhood obesity in their offspring

AIM

Obesity at the start of pregnancy has been rising worldwide, increasing the risk of maternal complications. We reviewed the independent effects of maternal obesity during pregnancy on neonatal adverse outcomes and the risk of childhood obesity and adverse cardio-metabolic profiles.

METHODS

We searched MEDLINE for papers published in English between December 2007 and November 2017, focusing primarily on human studies published in the last five years. However, we also chose to highlight examples derived from model animals that could bring mechanistic insight and preventive and therapeutic avenues.

RESULTS

Our review showed that maternal obesity had independent effects on neonatal adverse outcomes such as macrosomia, perinatal mortality and birth defects. Maternal obesity alone increased the risks for adverse neonatal outcomes, including macrosomia, perinatal mortality, induced preterm birth and birth defects. In association with excess gestational weight gain, mainly early in pregnancy, increased the risks of childhood obesity, higher fat mass and, to a smaller extent, adverse cardio-metabolic profiles. Animal models highlighted sexually dimorphic responses to maternal obesity.

CONCLUSION

Maternal obesity induced serious adverse neonatal effects and was associated with childhood obesity in their offspring. The peri-conceptional period is critical for metabolic programming, and obese women need close monitoring from conception.

Maternal Overnutrition Programs Central Inflammation and Addiction-Like Behavior in Offspring

Obesity or maternal overnutrition during pregnancy and lactation might have long-term consequences in offspring health. Fetal programming is characterized by adaptive responses to specific environmental conditions during early life stages. Programming alters gene expression through epigenetic modifications leading to a transgenerational effect of behavioral phenotypes in the offspring. Maternal intake of hypercaloric diets during fetal development programs aberrant behaviors resembling addiction in offspring. Programming by hypercaloric surplus sets a gene expression pattern modulating axonal pruning, synaptic signaling, and synaptic plasticity in selective regions of the reward system. Likewise, fetal programming can promote an inflammatory phenotype in peripheral and central sites through different cell types such as microglia and T and B cells, which contribute to disrupted energy sensing and behavioral pathways. The molecular mechanism that regulates the central and peripheral immune cross-talk during fetal programming and its relevance on offspring's addictive behavior susceptibility is still unclear. Here, we review the most relevant scientific reports about the impact of hypercaloric nutritional fetal programming on central and peripheral inflammation and its effects on addictive behavior of the offspring.

Up-regulation of renal renin-angiotensin system and inflammatory mechanisms in the prenatal programming by low-protein diet: beneficial effect of the post-weaning losartan treatment

Previous studies have shown that the renin-angiotensin system (RAS) is affected by adverse maternal nutrition during pregnancy. The aim of this study was to investigate the effects of a maternal low-protein diet on proinflammatory cytokines, reactive oxygen species and RAS components in kidney samples isolated from adult male offspring. We hypothesized that post-weaning losartan treatment would have beneficial effects on RAS activity and inflammatory and oxidative stress markers in these animals. Pregnant Sprague-Dawley rats were fed with a control (20% casein) or low-protein diet (LP) (6% casein) throughout gestation. After weaning, the LP pups were randomly assigned to LP and LP-losartan groups (AT1 receptor blockade: 10 mg/kg/day until 20 weeks of age). At 20 weeks of age, blood pressure levels were higher and renal RAS was activated in the LP group. We also observed several adverse effects in the kidneys of the LP group, including a higher number of CD3, CD68 and proliferating cell nuclear antigen-positive cells and higher levels of collagen and reactive oxygen species in the kidney. Further, our results revealed that post-weaning losartan treatment completely abolished immune cell infiltration and intrarenal RAS activation in the kidneys of LP rats. The prevention of augmentation of angiotensin (Ang II) concentration abolished inflammatory and fibrotic events, indicating that Ang II via the AT1 receptor is essential for pathological initiation. Our results suggest that the prenatal programming of hypertension is dependent on the up-regulation of local RAS and presence of immune cells in the kidney.

Obesity and High-Fat Diet Induce Distinct Changes in Placental Gene Expression and Pregnancy Outcome

Obese women are at high risk of pregnancy complications, including preeclampsia, miscarriage, preterm birth, stillbirth, and neonatal death. In the current study, we aimed to determine the effects of obesity on pregnancy outcome and placental gene expression in preclinical mouse models of genetic and nutritional obesity. The leptin receptor (LepR) null-reactivatable (LepRloxTB), LepR-deficient (Leprdb/+), and high-fat diet (HFD)-fed mice were assessed for fertility, pregnancy outcome, placental morphology, and placental transcriptome using standard quantitative polymerase chain reaction (qPCR) and qPCR arrays. The restoration of fertility of LepRloxTB was performed by stereotaxic delivery of adeno-associated virus-Cre into the hypothalamic ventral premammillary nucleus. Fertile LepRloxTB females were morbidly obese, whereas the wild-type mice-fed HFD showed only a mild increase in body weight. Approximately 80% of the LepRloxTB females had embryo resorptions (∼40% of the embryos). In HFD mice, the number of resorptions was not different from controls fed a regular diet. Placentas of resorbed embryos from obese mice displayed necrosis and inflammatory infiltrate in the labyrinth and changes in the expression of genes associated with angiogenesis and inflammation (e.g., Vegfa, Hif1a, Nfkbia, Tlr3, Tlr4). In contrast, placentas from embryos of females on HFD showed changes in a different set of genes, mostly associated with cellular growth and response to stress (e.g., Plg, Ang, Igf1, Igfbp1, Fgf2, Tgfb2, Serpinf1). Sexual dimorphism in gene expression was only apparent in placentas from obese LepRloxTB mice. Our findings indicate that an obese environment and HFD have distinct effects on pregnancy outcome and the placental transcriptome.

Placental lipid processing in response to a maternal high-fat diet and diabetes in rats

BackgroundDiabetes and obesity during pregnancy have an impact on the health of both mothers and developing babies. Prevention focuses on glycemic control, but increasing evidence implicates a role for lipids. Using a rat model, we showed that a maternal high-fat (HF) diet increased perinatal morbidity and mortality, but lipid processing across the maternal-placental-fetal triad remained unstudied. We hypothesized that HF diet would disrupt placental lipid processing to exaggerate fuel-mediated consequences of diabetic pregnancy.MethodsWe compared circulating lipid profiles, hormones, and inflammatory markers in dams and rat offspring from normal, diabetes-exposed, HF-diet-exposed, and combination-exposed pregnancies. Placentae were examined for lipid accumulation and expression of fuel transporters.ResultsMaternal HF diet exaggerated hyperlipidemia of pregnancy, with diabetes marked dyslipidemia developed in dams but not in offspring. Placentae demonstrated lipid accumulation and lower expression of fatty acid (FA) transporters. Diet-exposed offspring had a lower fraction of circulating essential FAs. Pregnancy loss was significantly higher in diet-exposed but not in diabetes-exposed pregnancies, which could not be explained by differences in hormone production. Although not confirmed, inflammation may play a role.ConclusionMaternal hyperlipidemia contributes to placental lipid droplet accumulation, perinatal mortality, and aberrant FA profiles that may influence the health of the developing offspring.

Placenta-specific gene manipulation in rabbits

Lentiviral gene constructs can be efficiently and specifically delivered to trophoblast cell lineages in rodents. In vivo genetic manipulation of trophoblast cell lines enables functional and developmental studies in the placenta. In this report we show that genetic modification can be produced in the extraembryonic tissues of rabbits by lentiviral gene constructs. When 8-16 cell stage embryos were injected with lentiviral particles, strong reporter gene expression resulted in the rabbit placenta. The expression pattern displayed some mosaicism. A strikingly high degree of mosaic GFP expression was detected in some parts of the yolk sac, which is a hypoblast-derived tissue. Whereas expression of the reporter gene construct was detected in placentas and yolk sacs, fetuses never expressed the transgene. As rabbits are an ideal model for functional studies in the placenta, our method would open new possibilities in rabbit biotechnology and placentation studies.

DOHaD at the intersection of maternal immune activation and maternal metabolic stress: a scoping review

The prenatal environment is now recognized as a key driver of non-communicable disease risk later in life. Within the developmental origins of health and disease (DOHaD) paradigm, studies are increasingly identifying links between maternal morbidity during pregnancy and disease later in life for offspring. Nutrient restriction, metabolic disorders during gestation, such as diabetes or obesity, and maternal immune activation provoked by infection have been linked to adverse health outcomes for offspring later in life. These factors frequently co-occur, but the potential for compounding effects of multiple morbidities on DOHaD-related outcomes has not received adequate attention. This is of particular importance in low- or middle-income countries (LMICs), which have ongoing high rates of infectious diseases and are now experiencing transitions from undernutrition to excess adiposity. The purpose of this scoping review is to summarize studies examining the effect and interaction of co-occurring metabolic or nutritional stressors and infectious diseases during gestation on DOHaD-related health outcomes. We identified nine studies in humans - four performed in the United States and five in LMICs. The most common outcome, also in seven of nine studies, was premature birth or low birth weight. We identified nine animal studies, six in mice, two in rats and one in sheep. The interaction between metabolic/nutritional exposures and infectious exposures had varying effects including synergism, inhibition and independent actions. No human studies were specifically designed to assess the interaction of metabolic/nutritional exposures and infectious diseases. Future studies of neonatal outcomes should measure these exposures and explicitly examine their concerted effect.

Interplay between Oxidative Stress and Nutrient Sensing Signaling in the Developmental Origins of Cardiovascular Disease

Cardiovascular disease (CVD) presents a global health burden, despite recent advances in management. CVD can originate from early life by so-called “developmental origins of health and disease” (DOHaD). Epidemiological and experimental evidence supports that early-life insults can induce programming of later CVD. Underlying the DOHaD concept, early intervention may offset programming process to prevent the development of CVD, namely reprogramming. Oxidative stress and nutrient sensing signals have been considered to be major mechanisms of cardiovascular programming, while the interplay between these two mechanisms have not been examined in detail. This review summarizes current evidence that supports the link between oxidative stress and nutrient sensing signaling to cardiovascular programming, with an emphasis on the l-arginine–asymmetric dimethylarginine (ADMA)–nitric oxide (NO) pathway. This review provides an overview of evidence from human studies supporting fetal programming of CVD, insight from animal models of cardiovascular programming and oxidative stress, impact of the l-arginine–ADMA–NO pathway in cardiovascular programming, the crosstalk between l-arginine metabolism and nutrient sensing signals, and application of reprogramming interventions to prevent the programming of CVD. A greater understanding of the mechanisms underlying cardiovascular programming is essential to developing early reprogramming interventions to combat the globally growing epidemic of CVD.

PPARγ agonist through the terminal differentiation phase is essential for adipogenic differentiation of fetal ovine preadipocytes

Background

Although the 3T3-L1 preadipocyte cell line represents an informative model for in vitro adipogenesis research, primary cultured cells are often needed to understand particular human or animal metabolic phenotypes. As demonstrated by in vitro cultured preadipocytes from large mammalian species, primary cultured cells require specific adipogenic differentiation conditions different to that of the 3T3-L1 cell line. These conditions are also species-specific and require optimization steps. However, efficient protocols to differentiate primary preadipocytes using alternative species to rodents are scarce. Sheep represent an amenable animal model for fetal biology and developmental origins of health and disease studies. In this work, we present with the first detailed procedure to efficiently differentiate primary fetal and adult ovine preadipocytes.

Methods

Fetal and adult ovine adipose and skin tissue harvest, preadipocyte and fibroblast isolation, proliferation, and standardization and optimization of a new adipogenic differentiation protocol. Use of commercial cell lines (3T3-L1 and NIH-3T3) for validation purposes. Oil red O stain and gene expression were used to validate adipogenic differentiation. ANOVA and Fisher’s exact test were used to determine statistical significance.

Results

Our optimized adipogenic differentiation method included a prolonged adipogenic cocktail exposure time from 2 to 8 days, higher insulin concentration, and supplementation with the peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone. This protocol was optimized for both, fetal and adult preadipocytes.

Conclusions

Our protocol enables successful adipogenic differentiation of fetal and adult ovine preadipocytes. This work demonstrates that compared to the 3T3-L1 cell line, fetal ovine preadipocytes require a longer exposure to the differentiation cocktail, and the need for IMBX, dexamethasone, and/or the PPARγ agonist rosiglitazone through the terminal differentiation phase. They also require higher insulin concentration during differentiation to enhance lipid accumulation and similar to human primary preadipocytes, PPARγ agonist supplementation is also required for ovine adipogenic differentiation. This work highlights species-specific differences requirements for adipogenic differentiation and the need to develop standardized methods to investigate comparative adipocyte biology.

Developmental Programming of Adult Disease: Reprogramming by Melatonin?

Adult-onset chronic non-communicable diseases (NCDs) can originate from early life through so-called the "developmental origins of health and disease" (DOHaD) or "developmental programming". The DOHaD concept offers the "reprogramming" strategy to shift the treatment from adulthood to early life, before clinical disease is apparent. Melatonin, an endogenous indoleamine produced by the pineal gland, has pleiotropic bioactivities those are beneficial in a variety of human diseases. Emerging evidence support that melatonin is closely inter-related to other proposed mechanisms contributing to the developmental programming of a variety of chronic NCDs. Recent animal studies have begun to unravel the multifunctional roles of melatonin in many experimental models of developmental programming. Even though some progress has been made in research on melatonin as a reprogramming strategy to prevent DOHaD-related NCDs, future human studies should aim at filling the translational gap between animal models and clinical trials. Here, we review several key themes on the reprogramming effects of melatonin in DOHaD research. We have particularly focused on the following areas: mechanisms of developmental programming; the interrelationship between melatonin and mechanisms underlying developmental programming; pathophysiological roles of melatonin in pregnancy and fetal development; and insight provided by animal models to support melatonin as a reprogramming therapy. Rates of NCDs are increasing faster than anticipated all over the world. Hence, there is an urgent need to understand reprogramming mechanisms of melatonin and to translate experimental research into clinical practice for halting a growing list of DOHaD-related NCDs.

Developmental Origins of Cardiometabolic Diseases: Role of the Maternal Diet

Developmental origins of cardiometabolic diseases have been related to maternal nutritional conditions. In this context, the rising incidence of arterial hypertension, diabetes type II, and dyslipidemia has been attributed to genetic programming. Besides, environmental conditions during perinatal development such as maternal undernutrition or overnutrition can program changes in the integration among physiological systems leading to cardiometabolic diseases. This phenomenon can be understood in the context of the phenotypic plasticity and refers to the adjustment of a phenotype in response to environmental input without genetic change, following a novel, or unusual input during development. Experimental studies indicate that fetal exposure to an adverse maternal environment may alter the morphology and physiology that contribute to the development of cardiometabolic diseases. It has been shown that both maternal protein restriction and overnutrition alter the central and peripheral control of arterial pressure and metabolism. This review will address the new concepts on the maternal diet induced-cardiometabolic diseases that include the potential role of the perinatal malnutrition.

Transforming Life: A Broad View of the Developmental Origins of Health and Disease Concept from an Ecological Justice Perspective

The influential scientist Rene J. Dubos (1901–1982) conducted groundbreaking studies concerning early-life environmental exposures (e.g., diet, social interactions, commensal microbiota, housing conditions) and adult disease. However, Dubos looked beyond the scientific focus on disease, arguing that “mere survival is not enough”. He defined mental health as fulfilling human potential, and expressed concerns about urbanization occurring in tandem with disappearing access to natural environments (and elements found within them); thus modernity could interfere with health via “missing exposures”. With the advantage of emerging research involving green space, the microbiome, biodiversity and positive psychology, we discuss ecological justice in the dysbiosphere and the forces—financial inequity, voids in public policy, marketing and otherwise—that interfere with the fundamental rights of children to thrive in a healthy urban ecosystem and learn respect for the natural environment. We emphasize health within the developmental origins of health and disease (DOHaD) rubric and suggest that greater focus on positive exposures might uncover mechanisms of resiliency that contribute to maximizing human potential. We will entrain our perspective to socioeconomic disadvantage in developed nations and what we have described as “grey space”; this is a mental as much as a physical environment, a space that serves to insidiously reinforce unhealthy behavior, compromise positive psychological outlook and, ultimately, trans-generational health. It is a dwelling place that cannot be fixed with encephalobiotics or the drug-class known as psychobiotics.