Feto-placental adaptations to maternal obesity in the baboon

Obesogenic Diet in Mice Leads to Inflammation and Oxidative Stress in the Mother in Association with Sex-Specific Changes in Fetal Development, Inflammatory Markers and Placental Transcriptome

BACKGROUND

Obesity during pregnancy is related to adverse maternal and neonatal outcomes. Factors involved in these outcomes may include increased maternal insulin resistance, inflammation, oxidative stress, and nutrient mishandling. The placenta is the primary determinant of fetal outcomes, and its function can be impacted by maternal obesity. The aim of this study on mice was to determine the effect of obesity on maternal lipid handling, inflammatory and redox state, and placental oxidative stress, inflammatory signaling, and gene expression relative to female and male fetal growth.

METHODS

Female mice were fed control or obesogenic high-fat/high-sugar diet (HFHS) from 9 weeks prior to, and during, pregnancy. On day 18.5 of pregnancy, maternal plasma, and liver, placenta, and fetal serum were collected to examine the immune and redox states. The placental labyrinth zone (Lz) was dissected for RNA-sequencing analysis of gene expression changes.

RESULTS

the HFHS diet induced, in the dams, hepatic steatosis, oxidative stress (reduced catalase, elevated protein oxidation) and the activation of pro-inflammatory pathways (p38-MAPK), along with imbalanced circulating cytokine concentrations (increased IL-6 and decreased IL-5 and IL-17A). HFHS fetuses were asymmetrically growth-restricted, showing sex-specific changes in circulating cytokines (GM-CSF, TNF-α, IL-6 and IFN-γ). The morphology of the placenta Lz was modified by an HFHS diet, in association with sex-specific alterations in the expression of genes and proteins implicated in oxidative stress, inflammation, and stress signaling. Placental gene expression changes were comparable to that seen in models of intrauterine inflammation and were related to a transcriptional network involving transcription factors, LYL1 and PLAG1.

CONCLUSION

This study shows that fetal growth restriction with maternal obesity is related to elevated oxidative stress, inflammatory pathways, and sex-specific placental changes. Our data are important, given the marked consequences and the rising rates of obesity worldwide.

Maternal obesity and placental function: impaired maternal-fetal axis

The prevalence of maternal obesity rapidly increases, which represents a major public health concern worldwide. Maternal obesity is characteristic by metabolic dysfunction and chronic inflammation. It is associated with health problems in both mother and offspring. Increasing evidence indicates that the placenta is an axis connecting maternal obesity with poor outcomes in the offspring. In this brief review, we have summarized the current data regarding deregulated placental function in maternal obesity. The data show that maternal obesity induces numerous placental defects, including lipid and glucose metabolism, stress response, inflammation, immune regulation and epigenetics. These placental defects affect each other and result in a stressful intrauterine environment, which transduces and mediates the adverse effects of maternal obesity to the fetus. Further investigations are required to explore the exact molecular alterations in the placenta in maternal obesity, which may pave the way to develop specific interventions for preventing epigenetic and metabolic programming in the fetus.

The relationship between placental thickness and gestational age in pregnant women: A cross-sectional study

Background and Aims

Estimating gestational age (GA) is of utmost importance to assess the condition of the fetus. Incorporating placental thickness and fetal biometrics in estimating GA may improve the accuracy of fetal age estimation. The aim of this study was to examine the relationship between placental thickness and GA in pregnant women referred to Al-Zahra Hospital's prenatal and emergency clinic in Rasht, Iran.

Methods

This cross-sectional study was conducted on pregnant women referred to Al-Zahra Clinic for prenatal care over a 6-month period. After obtaining informed consent, data were collected on the date of the first day of the last safe menstruation, average body mass index, and medical and surgical history. Placental thickness was estimated using ultrasound and various clinical information was recorded. The data were then analyzed using Pearson correlation analysis in SPSS software version 21.

Results

The results showed a significant correlation between GA and placental thickness (p < 0.0001, r = 0.729). Placental thickness increased with increasing GA. There was also a significant relationship between placental thickness and placental location (p = 0.009, r = 0.14). In the posterior position, placental thickness increased by 14% or 0.14. The placental thickness in the posterior position (29.49 ± 0.75) was greater than the anterior position (26.94 ± 10.72).

Conclusion

The findings of this study suggest that there is a significant increase in placental thickness with increasing GA during the first and second trimesters. Additionally, placental thickness significantly increased in the posterior placental position, as well as in women with high BMI. Therefore, it is recommended that measuring placental thickness should be routine during obstetric ultrasounds.

Maternal diet alters long-term innate immune cell memory in fetal and juvenile hematopoietic stem and progenitor cells in nonhuman primate offspring

Maternal overnutrition increases inflammatory and metabolic disease risk in postnatal offspring. This constitutes a major public health concern due to increasing prevalence of these diseases, yet mechanisms remain unclear. Here, using nonhuman primate models, we show that maternal Western-style diet (mWSD) exposure is associated with persistent pro-inflammatory phenotypes at the transcriptional, metabolic, and functional levels in bone marrow-derived macrophages (BMDMs) from 3-year-old juvenile offspring and in hematopoietic stem and progenitor cells (HSPCs) from fetal and juvenile bone marrow and fetal liver. mWSD exposure is also associated with increased oleic acid in fetal and juvenile bone marrow and fetal liver. Assay for transposase-accessible chromatin with sequencing (ATAC-seq) profiling of HSPCs and BMDMs from mWSD-exposed juveniles supports a model in which HSPCs transmit pro-inflammatory memory to myeloid cells beginning in utero. These findings show that maternal diet alters long-term immune cell developmental programming in HSPCs with proposed consequences for chronic diseases featuring altered immune/inflammatory activation across the lifespan.

Preeclampsia and the Kidney: Pathophysiology and Clinical Implications

Preeclampsia and other hypertensive disorders of pregnancy are major contributors to maternal morbidity and mortality worldwide. This group of disorders includes chronic hypertension, gestational hypertension, preeclampsia, preeclampsia superimposed on chronic hypertension, and eclampsia. The body undergoes important physiological changes during pregnancy to allow for normal placental and fetal development. Several mechanisms have been proposed that may lead to preeclampsia, including abnormal placentation and placental hypoxia, impaired angiogenesis, excessive pro-inflammatory response, immune system imbalance, abnormalities of cellular senescence, alterations in regulation and activity of angiotensin II, and oxidative stress, ultimately resulting in upregulation of multiple mediators of endothelial cell dysfunction leading to maternal disease. The clinical implications of preeclampsia are significant as there are important short-term and long-term health consequences for those affected. Preeclampsia leads to increased risk of preterm delivery and increased morbidity and mortality of both the developing fetus and mother. Preeclampsia also commonly leads to acute kidney injury, and women who experience preeclampsia or another hypertensive disorder of pregnancy are at increased lifetime risk of chronic kidney disease and cardiovascular disease. An understanding of normal pregnancy physiology and the pathophysiology of preeclampsia is essential to develop novel treatment approaches and manage patients with preeclampsia and hypertensive disorders of pregnancy. © 2023 American Physiological Society. Compr Physiol 13:4231-4267, 2023.

Influence of maternal obesity on the multi-omics profiles of the maternal body, gestational tissue, and offspring

Epidemiological studies show that obesity during pregnancy affects more than half of the pregnancies in the developed countries and is associated with obstetric problems and poor outcomes. Obesity tends to increase the incidence of complications. Furthermore, the resulting offspring are also adversely affected. However, the molecular mechanisms of obesity leading to poor pregnancy outcomes remain unclear. Omics methods are used for genetic diagnosis and marker discovery. The aim of this review was to summarize the maternal and fetal pathophysiological alterations induced by gestational obesity,identified using multi-omics detection techniques, and to generalize the biological functions and potential mechanisms of the differentially expressed molecules.

Diallyl Trisulfide Promotes Placental Angiogenesis by Regulating Lipid Metabolism and Alleviating Inflammatory Responses in Obese Pregnant Mice

The placental tissue serves as an exchanger between the mother and the fetus during pregnancy in mammals. Proper placental angiogenesis is central to the health of both the mother and the growth and development of the fetus. Maternal obesity is associated with impaired placental function, resulting in restricted placental blood vessel development and fetal developmental disorders. Hydrogen sulfide (H₂S) is a ubiquitous second messenger in cells that has many biological effects such as promoting angiogenesis, anti-inflammation, anti-oxidation and promoting lipid metabolism. However, in the case of maternal obesity, whether H₂S can be used as an important signaling molecule to regulate body metabolism, alleviate placental inflammation levels and promote placental angiogenesis is still unclear. In this study, diallyl trisulfide (DATS), which is a well-known H₂S donor, was derived from garlic and used to treat obese pregnant mice induced by a high-fat diet, to determine its effects on lipid metabolism and inflammation, as well as placental morphology and placental angiogenesis. Here, we show that DATS treatment increased litter size and alive litter size. DATS improved the H₂S level in the serum and placenta of the mice. In addition, DATS treatment improved insulin resistance and lipid metabolism, reduced the inflammatory response and alleviated placental vascular dysplasia caused by obesity in obese mice. In summary, our research revealed that H₂S is an important signaling molecule in vivo, which can regulate placental angiogenesis and improve the reproductive performance in maternal obesity. The addition of H₂S donor DATS during pregnancy promoted placental angiogenesis by regulating lipid metabolism and alleviating inflammatory responses in obese pregnant mice.

Diet-induced maternal obesity impacts feto-placental growth and induces sex-specific alterations in placental morphology, mitochondrial bioenergetics, dynamics, lipid metabolism and oxidative stress in mice

AIM

The current study investigated the impact of maternal obesity on placental phenotype in relation to fetal growth and sex.

METHODS

Female C57BL6/J mice were fed either a diet high in fat and sugar or a standard chow diet, for 6 weeks prior to, and during, pregnancy. At day 19 of gestation, placental morphology and mitochondrial respiration and dynamics were assessed using high-resolution respirometry, stereology, and molecular analyses.

RESULTS

Diet-induced maternal obesity increased the rate of small for gestational age fetuses in both sexes, and increased blood glucose concentrations in offspring. Placental weight, surface area, and maternal blood spaces were decreased in both sexes, with reductions in placental trophoblast volume, oxygen diffusing capacity, and an increased barrier to transfer in males only. Despite these morphological changes, placental mitochondrial respiration was unaffected by maternal obesity, although the influence of fetal sex on placental respiratory capacity varied between dietary groups. Moreover, in males, but not females, maternal obesity increased mitochondrial complexes (II and ATP synthase) and fission protein DRP1 abundance. It also reduced phosphorylated AMPK and capacity for lipid synthesis, while increasing indices of oxidative stress, specifically in males. In females only, placental mitochondrial biogenesis and capacity for lipid synthesis, were both enhanced. The abundance of uncoupling protein-2 was decreased by maternal obesity in both fetal sexes.

CONCLUSION

Maternal obesity exerts sex-dependent changes in placental phenotype in association with alterations in fetal growth and substrate supply. These findings may inform the design of personalized lifestyle interventions or therapies for obese pregnant women.

Maternal Obesity Programming of Perivascular Adipose Tissue and Associated Immune Cells: An Understudied Area With Few Answers and Many Questions

At present, the worldwide prevalence of obesity has become alarmingly high with estimates foreshadowing a continued escalation in the future. Furthermore, there is growing evidence attributing an individual’s predisposition for developing obesity to maternal health during gestation. Currently, 60% of pregnancies in the US are to either overweight or obese mothers which in turn contributes to the persistent rise in obesity rates. While obesity itself is problematic, it conveys an increased risk for several diseases such as diabetes, inflammatory disorders, cancer and cardiovascular disease (CVD). Additionally, as we are learning more about the mechanisms underlying CVD, much attention has been brought to the role of perivascular adipose tissue (PVAT) in maintaining cardiovascular health. PVAT regulates vascular tone and for a significant number of individuals, obesity elicits PVAT disruption and dysregulation of vascular function. Obesity elicits changes in adipocyte and leukocyte populations within PVAT leading to an inflammatory state which promotes vasoconstriction thereby aiding the onset/progression of CVD. Our current understanding of obesity, PVAT and CVD has only been examined at the individual level without consideration for a maternal programming effect. It is unknown if maternal obesity affects the propensity for PVAT remodeling in the offspring, thereby enhancing the obesity/CVD link, and what role PVAT leukocytes play in this process. This perspective will focus on the maternal contribution of the interplay between obesity, PVAT disruption and CVD and will highlight the leukocyte/PVAT interaction as a novel target to stem the tide of the current obesity epidemic and its secondary health consequences.

Obesity and Maternal-Placental-Fetal Immunology and Health

Obesity rates in women of childbearing age is now at 29%, according to recent CDC reports. It is known that obesity is associated with oxidative stress and inflammation, including disruptions in cellular function and cytokine levels. In pregnant women who are obese, associated placental dysfunction can lead to small for gestational age (SGA) infants. More frequently, however, maternal obesity is associated with large for gestational age (LGA) newborns, who also have higher incidence of metabolic disease and asthma due to elevated levels of inflammation. In addition, anthropogenic environmental exposures to "endocrine disrupting" and "forever" chemicals affect obesity, as well as maternal physiology, the placenta, and fetal development. Placental function is intimately associated with the control of inflammation during pregnancy. There is a large amount of literature examining the relationship of placental immunology, both cellular and humoral, with pregnancy and neonatal outcomes. Cells such as placental macrophages and NK cells have been implicated in spontaneous miscarriage, preeclampsia, preterm birth, perinatal neuroinflammation, and other post-natal conditions. Differing levels of placental cytokines and molecular inflammatory mediators also have known associations with preeclampsia and developmental outcomes. In this review, we will specifically examine the literature regarding maternal, placental, and fetal immunology and how it is altered by maternal obesity and environmental chemicals. We will additionally describe the relationship between placental immune function and clinical outcomes, including neonatal conditions, autoimmune disease, allergies, immunodeficiency, metabolic and endocrine conditions, neurodevelopment, and psychiatric disorders.

Effects of maternal obesity in an ovine model on metabolic outcomes in F2 adults and F3 neonates

Accumulating evidence suggests that indications of metabolic syndrome can be inherited through the germline as a result of maternal obesity. We hypothesized that diet-induced maternal obesity during gestation would program metabolic consequences for multiple generations of offspring, even when first, second, and third generation offspring (F1, F2, F3, respectively) were fed only to requirements. Control (CON) and obese (OB) ewes (generation 0; F0) were bred to a single ram to produce the first generation of offspring (F1). From 60 d prior to conception through term, CONF0 ate 100% National Research Council recommendations (NRC), while OBF0 ewes ate 150% NRC. All F1, F2, and F3 ate 100% NRC after weaning. All mature F1 ewes were bred to a single ram to generate CONF2 (n = 6) and OBF2 (n = 10). All mature F2 ewes were bred to a single ram to produce CONF3 (n = 6) and OBF3 (n = 10). OBF2 ewes exhibited greater (P < 0.0001) plasma cortisol than CONF2 throughout gestation. A glucose tolerance test at 90% gestation revealed OBF2 ewes had higher (P < 0.05) insulin response with similar glucose, resulting in greater (P < 0.05) insulin resistance. OBF3 neonates had similar weight, lean mass, and body fat mass to CONF3 neonates. These data suggest that multigenerational programming of adverse metabolic phenotypes occur in association with F0 maternal obesity, yet adiposity may return to CON levels in F3 neonates.

Effects of Maternal Obesity On Placental Phenotype

The incidence of obesity is rising rapidly worldwide with the consequence that more women are entering pregnancy overweight or obese. This leads to an increased incidence of clinical complications during pregnancy and of poor obstetric outcomes. The offspring of obese pregnancies are often macrosomic at birth although there is also a subset of the progeny that are growth-restricted at term. Maternal obesity during pregnancy is also associated with cardiovascular, metabolic and endocrine dysfunction in the offspring later in life. As the interface between the mother and fetus, the placenta has a central role in programming intrauterine development and is known to adapt its phenotype in response to environmental conditions such as maternal undernutrition and hypoxia. However, less is known about placental function in the abnormal metabolic and endocrine environment associated with maternal obesity during pregnancy. This review discusses the placental consequences of maternal obesity induced either naturally or experimentally by increasing maternal nutritional intake and/or changing the dietary composition. It takes a comparative, multi-species approach and focusses on placental size, morphology, nutrient transport, metabolism and endocrine function during the later stages of obese pregnancy. It also examines the interventions that have been made during pregnancy in an attempt to alleviate the more adverse impacts of maternal obesity on placental phenotype. The review highlights the potential role of adaptations in placental phenotype as a contributory factor to the pregnancy complications and changes in fetal growth and development that are associated with maternal obesity.

Risk factors and fetal outcomes for preeclampsia in a Colombian cohort

In Latin America and the Caribbean, hypertensive pregnancy disorders are responsible for almost 26% of all maternal deaths [1] and, in Colombia, they account for 59% of all severe maternal morbidity (SMM) cases, and 59.7% of all SMM cases in adolescents [2]. One of the most important hypertensive pregnancy disorders is preeclampsia (PE). Lives can be saved, if PE is prevented, or detected early and properly managed. Prevention and detection depend on identifying the risk factors associated with PE, and, as these have been shown vary by population, they should be determined on a population-by-population basis. The following study utilized the nested case-control model to evaluate 45 potential PE risk factors of a cohort in Bogotá, Colombia, making it perhaps the most comprehensive study of its kind in Colombia. It found PE to have a statistically significant association with 7 of the 45 factors evaluated: 1) pre-gestational BMI >30 kg/m², 2) pregnancy weight gain >12 kg, 3) previous history preeclampsia/eclampsia, 4) previous history of IUGR-SGA (Intrauterine Growth Restriction-Small for Gestational Age), 5) maternal age <20 or ≥35 years (20–34 was not associated), and 6) family history of diabetes. Finally, prenatal consumption of folic acid was found to lower the risk of PE. We recommend that, in Colombia, factors 1–6 be used to identify at risk mothers during pregnancy check-ups; that mothers be encouraged to take folic acid during pregnancy; and, that Colombia's health system and public policy address the problem of pregestational obesity.

Developmental programming of peripheral diseases in offspring exposed to maternal obesity during pregnancy

Obesity is an increasing global health epidemic that affects all ages, including women of reproductive age. During pregnancy, maternal obesity is associated with adverse pregnancy outcomes that lead to complications for the mother. In addition, maternal obesity can increase the risk of poor perinatal outcomes for the infant due to altered development. Recent research has investigated the effects of maternal obesity on peripheral organ development and health in later life in offspring. In this review, we have summarized studies that investigated the programming effects of maternal obesity before and during pregnancy on metabolic, cardiovascular, immune, and microbiome perturbations in offspring. Epidemiological studies investigating the effects of maternal obesity on offspring development can be complex due to other copathologies and genetic diversity. Animal studies have provided some insights into the specific mechanisms and pathways involved in programming peripheral disease risk. The effects of maternal obesity during pregnancy on offspring development are often sex specific, with sex-specific changes in placental transport and function suggestive that this organ is likely to play a central role. We believe that this review will assist in facilitating future investigations regarding the underlying mechanisms that link maternal obesity and offspring disease risk in peripheral organs.

Strength of nonhuman primate studies of developmental programming: review of sample sizes, challenges, and steps for future work

Nonhuman primate (NHP) studies are crucial to biomedical research. NHPs are the species most similar to humans in lifespan, body size, and hormonal profiles. Planning research requires statistical power evaluation, which is difficult to perform when lacking directly relevant preliminary data. This is especially true for NHP developmental programming studies, which are scarce. We review the sample sizes reported, challenges, areas needing further work, and goals of NHP maternal nutritional programming studies. The literature search included 27 keywords, for example, maternal obesity, intrauterine growth restriction, maternal high-fat diet, and maternal nutrient reduction. Only fetal and postnatal offspring studies involving tissue collection or imaging were included. Twenty-eight studies investigated maternal over-nutrition and 33 under-nutrition; 23 involved macaques and 38 baboons. Analysis by sex was performed in 19; minimum group size ranged from 1 to 8 (mean 4.7 ± 0.52, median 4, mode 3) and maximum group size from 3 to 16 (8.3 ± 0.93, 8, 8). Sexes were pooled in 42 studies; minimum group size ranged from 2 to 16 (mean 5.3 ± 0.35, median 6, mode 6) and maximum group size from 4 to 26 (10.2 ± 0.92, 8, 8). A typical study with sex-based analyses had group size minimum 4 and maximum 8 per sex. Among studies with sexes pooled, minimum group size averaged 6 and maximum 8. All studies reported some significant differences between groups. Therefore, studies with group sizes 3-8 can detect significance between groups. To address deficiencies in the literature, goals include increasing age range, more frequently considering sex as a biological variable, expanding topics, replicating studies, exploring intergenerational effects, and examining interventions.

Fetal brain and placental programming in maternal obesity: A review of human and animal model studies

Both human epidemiologic and animal model studies demonstrate that prenatal and lactational exposure to maternal obesity and high-fat diet are associated with adverse neurodevelopmental outcomes in offspring. Neurodevelopmental outcomes described in offspring of obese women include cognitive impairment, autism spectrum disorder (ASD), attention deficit hyperactivity disorder, anxiety and depression, disordered eating, and propensity for reward-driven behavior, among others. This review synthesizes human and animal data linking maternal obesity and high-fat diet consumption to abnormal fetal brain development, and neurodevelopmental and psychiatric morbidity in offspring. It highlights key mechanisms by which maternal obesity and maternal diet impact fetal and offspring development, and sex differences in offspring programming. In addition, we review placental effects of maternal obesity, and the role the placenta might play as an indicator vs mediator of fetal programming.

Impact of pregravid obesity on maternal and fetal immunity: Fertile grounds for reprogramming

Maternal pregravid obesity results in several adverse health outcomes during pregnancy, including increased risk of gestational diabetes, preeclampsia, placental abruption, and complications at delivery. Additionally, pregravid obesity and in utero exposure to high fat diet have been shown to have detrimental effects on fetal programming, predisposing the offspring to adverse cardiometabolic, endocrine, and neurodevelopmental outcomes. More recently, a deeper appreciation for the modulation of offspring immunity and infectious disease-related outcomes by maternal pregravid obesity has emerged. This review will describe currently available animal models for studying the impact of maternal pregravid obesity on fetal immunity and review the data from clinical and animal model studies. We also examine the burden of pregravid obesity on the maternal-fetal interface and the link between placental and systemic inflammation. Finally, we discuss future studies needed to identify key mechanistic underpinnings that link maternal inflammatory changes and fetal cellular reprogramming events.

High-fat diet intake modulates maternal intestinal adaptations to pregnancy and results in placental hypoxia, as well as altered fetal gut barrier proteins and immune markers

KEY POINTS

Maternal obesity has been associated with shifts in intestinal microbiota, which may contribute to impaired barrier function Impaired barrier function may expose the placenta and fetus to pro-inflammatory mediators We investigated the impacts of diet-induced obesity in mice on maternal and fetal intestinal structure and placental vascularization Diet-induced obesity decreased maternal intestinal short chain fatty acids and their receptors, impaired gut barrier integrity and was associated with fetal intestinal inflammation. Placenta from obese mothers showed blood vessel immaturity, hypoxia, increased transcript levels of inflammation, autophagy and altered levels of endoplasmic reticulum stress markers. These data suggest that maternal intestinal changes probably contribute to adverse placental adaptations and also impart an increased risk of obesity in the offspring via alterations in fetal gut development.

ABSTRACT

Shifts in maternal intestinal microbiota have been implicated in metabolic adaptations to pregnancy. In the present study, we generated cohorts of female C57BL/6J mice fed a control (17% kcal fat, n = 10-14) or a high-fat diet (HFD 60% kcal from fat, n = 10-14; ad libitum) aiming to investigate the impact on the maternal gut microbiota, intestinal inflammation and gut barrier integrity, placental inflammation and fetal intestinal development at embryonic day 18.5. HFD was associated with decreased relative abundances of short-chain fatty acid (SCFA) producing genera during pregnancy. These diet-induced shifts paralleled decreased maternal intestinal mRNA levels of SCFA receptor Gpr41, modestly decreased cecal butyrate, and altered mRNA levels of inflammatory cytokines and immune cell markers in the maternal intestine. Maternal HFD resulted in impaired gut barrier integrity, with corresponding increases in circulating maternal levels of lipopolysaccharide (LPS) and tumour necrosis factor. Placentas from HFD dams demonstrated blood vessel immaturity and hypoxia; decreased free carnitine, acylcarnitine derivatives and trimethylamine-N-oxide; and altered mRNA levels of inflammation, autophagy, and ER stress markers. HFD exposed fetuses had increased activation of nuclear factor-kappa B and inhibition of the unfolded protein response in the developing intestine. Taken together, these data suggest that HFD intake prior to and during pregnancy shifts the composition of the maternal gut microbiota and impairs gut barrier integrity, resulting in increased maternal circulating LPS, which may ultimate contribute to changes in placental vascularization and fetal gut development.

A free-choice high-fat, high-sucrose diet induces hyperphagia, obesity, and cardiovascular dysfunction in female cycling and pregnant rats

The main objective of these studies was to characterize metabolic, body composition, and cardiovascular responses to a free-choice high-fat, high-sucrose diet in female cycling and pregnant rats. In the nonpregnant state, female Sprague-Dawley rats offered a 3-wk free-choice high-fat, high-sucrose diet had greater energy intake, adiposity, serum leptin, and triglyceride concentrations compared with rats fed with standard chow and developed glucose intolerance. In addition, choice-diet-fed rats had larger cardiac ventricular weights, smaller kidney and pancreas weights, and higher blood pressure than chow-fed rats, but they did not exhibit resistance artery endothelial dysfunction. When the free-choice diet continued throughout pregnancy, rats remained hyperphagic, hyperleptinemic, and obese. Choice pregnant rats exhibited uterine artery endothelial dysfunction and had smaller fetuses compared with chow pregnant rats. Pregnancy normalized mean arterial blood pressure and pancreas weights in choice rats. These studies are the first to provide a comprehensive evaluation of free-choice high-fat, high-sucrose diet on metabolic and cardiovascular functions in female rats, extending the previous studies in males to female cycling and pregnant rodents. Free-choice diet may provide a new model of preconceptual maternal obesity to study the role of increased energy intake, individual food components, and preexisting maternal obesity on maternal and offspring physiological responses during pregnancy and after birth.

Chronic hyperandrogenemia and western-style diet beginning at puberty reduces fertility and increases metabolic dysfunction during pregnancy in young adult, female macaques

STUDY QUESTION

What are the impacts of elevated testosterone (T) and an obesogenic western-style diet (WSD), either independently or together, on fertility and metabolic adaptations of pregnancy in primates?

SUMMARY ANSWER

Testosterone increases the time to achieve pregnancy, while a WSD reduces overall fertility, and the combination of testosterone and WSD additionally impairs glucose tolerance and causes pregnancy loss.

WHAT IS KNOWN ALREADY

Both hyperandrogenemia and obesity are hallmarks of polycystic ovary syndrome, which is a leading cause of infertility among women worldwide. Female macaques receiving T and WSD beginning at puberty show increased metabolic, ovarian and uterine dysfunction in the non-pregnant state by 3 years of treatment.

STUDY DESIGN, SIZE, DURATION

The same cohort of female rhesus macaques continued treatments from the time of puberty (2.5 years) to 4 years, including this fertility trial. There were four groups (n = 9-10/group): controls (C), T-treated (T; average total serum level 1.35 ng/ml), WSD-treated, and combined T and WSD-treated (T + WSD) females.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Females, which were typically having menstrual cycles, were paired for 4 days with a proven male breeder following the late follicular rise in circulating estradiol (≥100 pg/ml). The presence of sperm in the reproductive tract was used to confirm mating. Animals went through up to three successive rounds of mating until they became pregnant, as confirmed by a rise in circulating mCG during the late luteal phase and ultrasound evidence of a gestational sac at Day 30 post-mating (GD30). Placental vascular parameters were also measured at GD30. Metabolic measurements consisted of fasting levels of blood glucose and insulin at approximately GD30, 60, 90 and 115, as well as an intravenous (iv) glucose tolerance test (GTT) at GD115.

MAIN RESULTS AND THE ROLE OF CHANCE

While all animals in the C and T groups eventually became pregnant, T-treated females on average had a greater interval to achieve pregnancy (P < 0.05). However, only ~70% of animals in the WSD and T + WSD groups became pregnant (P < 0.004). One pregnancy in T + WSD group resulted in an anembryonic pregnancy which miscarried around GD60, while another T + WSD female conceived with a rare identical twin pregnancy which required cessation due to impending fetal loss at GD106. Thus, the number of viable fetuses was less in the T + WSD group, compared to C, T or WSD. Placental blood volume at GD30 was reduced in all treatments compared to the C group (P < 0.05). Maternal P4 levels were elevated in the WSD (P < 0.03) group and E2 levels were elevated in T + WSD animals (P < 0.05). An increase in serum A4 levels throughout gestation was observed in all groups (P < 0.03) except WSD (P = 0.3). All groups displayed increased insulin resistance with pregnancy, as measured from the ivGTT during pregnancy. However, only the T + WSD group had a significant increase in fasting glucose levels and glucose clearance during the GTT indicating a worsened glucose tolerance. WSD treatment decreased female fetuses third trimester weights, but there was an interaction between WSD and T to increase female fetal weight when normalized to maternal weight.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

The small number of pregnancies in the WSD and T + WSD groups hampers the ability to make definitive conclusions on effects during gestation. Also, the high fertility rate in the controls indicates the cohort was at their breeding prime age, which may impair the ability to observe subtle fertility defects. The low number of fetuses used for male and female analysis requires additional studies.

WIDER IMPLICATIONS OF THE FINDINGS

The current findings strongly suggest that both hyperandrogenemia and obesity have detrimental effects on fertility and gestation in primates, which may be directly relevant to women with polycystic ovary syndrome.

STUDY FUNDING/COMPETING INTEREST(S)

All ONPRC Cores and Units were supported by NIH Grant P51 OD011092 awarded to ONPRC. Research reported in this publication was supported by the Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD) of the National Institutes of Health (NIH) under Award Number P50HD071836 (to R.L.S.). The authors have no competing conflict of interests to disclose.

Differential effects of high-fat diets before pregnancy and/or during pregnancy on fetal growth development

AIMS

The aim of the study was to investigate the effects of high-fat diets before pregnancy and/or during pregnancy on fetal development.

MAIN METHODS

Female mice were fed with standard diets (SD) or high-fat diets (HFD). After 12 weeks, females were mated. In the SD + SD and HFD + SD groups, pregnant mice were fed with standard diets. In the SD + HFD and HFD + HFD groups, pregnant mice were fed with high-fat diets. All pregnant mice were sacrificed on gestational day (GD) 16.

KEY FINDINGS

Fetal weight and crown-rump length were increased in SD + HFD-fed mice, whereas were decreased in HFD + SD-fed mice. The levels of CRP and TNF-α in maternal serum and amniotic fluid were elevated in all HFD-fed mice. Placenta weight was elevated in SD + HFD-fed but not in HFD + SD-fed mice. Blood sinusoid areas, and the number of Ki67-positive cells, a marker of cell proliferation, were elevated in placental labyrinth layer of SD + HFD-fed mice, but decreased in HFD + SD-fed mice. Finally, placental Fatp1, a fatty acid transporter gene, was up-regulated in SD + HFD-fed mice. By contrary, placental Fatp1, and Snat2, an amino acid transporter, were down-regulated in HFD + SD-fed mice. Moreover, the levels of placental FATP4 and SNAT2 were up-regulated in SD + HFD-fed mice.

SIGNIFICANCE

HFD before pregnancy and HFD during pregnancy differentially disturb fetal growth development. HFD before pregnancy-induced fetal SGA might be partially attributed to inflammatory cytokines and mediators derived from maternal adipose tissue. By contrary, HFD during pregnancy-induced fetal overweight may be partially attributed to the increase of placental nutrient transport capacity.

Papio spp. Colon microbiome and its link to obesity in pregnancy

INTRODUCTION

Gut microbial communities are critical players in the pathogenesis of obesity. Pregnancy is associated with increased bacterial load and changes in gut bacterial diversity. Sparse data exist regarding composition of gut microbial communities in obesity combined with pregnancy.

MATERIAL AND METHODS

Banked tissues were collected under sterile conditions during necropsy, from three non-obese (nOb) and four obese (Ob) near-term pregnant baboons. Sequences were assigned taxonomy using the Ribosomal Database Project classifier. Microbiome abundance and its difference between distinct groups were assessed by a nonparametric test.

RESULTS

Three families predominated in both the nOb and Ob colonic microbiome: Prevotellaceae (25.98% and 32.71% respectively), Ruminococcaceae (12.96% and 7.48%), and Lachnospiraceae (8.78% and 11.74%). Seven families of the colon microbiome displayed differences between Ob and nOb groups.

CONCLUSION

Changes in gut microbiome in pregnant obese animals open the venue for dietary manipulation in pregnancy.

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 obesity stimulates lipotoxicity and up-regulates inflammatory signaling pathways in the full-term swine placenta

This study aimed to investigate the effects of back-fat thickness (BF), at mating of sows, on placental lipotoxicity, oxidative stress, and inflammation. We performed iTRAQ labeling-based proteomic analysis on term placentas obtained by vaginal delivery from BFI (15-20 mm, control) and BFII (21-27 mm, obese) sows formed according to BF at mating. Proteomic analysis revealed 413 proteins to be significantly different in placenta from BFII sows by ≥1.2-fold. Gene ontology (GO) analysis identified proteins related to lipid metabolism and inflammatory response to be altered in placenta from obese sows. Indicative of a lipotoxic placental environment, increased placental lipid, and up-regulated mRNA expression of lipogenic genes, including ADRP (p = .06), PPARD, FASN, ACACA, DGAT1, and LIPIN3, were associated with decreased AMPK and increased activation of WNT signaling in placenta from BFII group (p < .05). Furthermore, we observed a 18% decrease in total antioxidant capacity (TAC), increased mRNA content of pro-inflammatory cytokines IL-6, IL-18, and TNF-α, and increased activation of inflammatory NF-κB and JNK signaling in placenta from BFII sows that was significantly associated with macrophage accumulation (p < .05). These findings suggest that maternal obesity aggravates a lipotoxic environment in pig term placenta that may be associated with placental dysfunction and impaired fetal growth.

The common marmoset monkey: avenues for exploring the prenatal, placental, and postnatal mechanisms in developmental programming of pediatric obesity

Animal models have been critical in building evidence that the prenatal experience and intrauterine environment are capable of exerting profound and permanent effects on metabolic health through developmental programming of obesity. However, despite physiological and evolutionary similarities, nonhuman primate models are relatively rare. The common marmoset monkey ( Callithrix jacchus) is a New World monkey that has been used as a biomedical model for well more than 50 years and has recently been framed as an appropriate model for exploring early-life impacts on later health and disease. The spontaneous, multifactorial, and early-life development of obesity in the common marmoset make it a valuable research model for advancing our knowledge about the role of the prenatal and placental mechanisms involved in developmental programming of obesity. This paper provides a brief overview of obesity in the common marmoset, followed by a discussion of marmoset reproduction and placental characteristics. We then discuss the occurrence and utility of variable intrauterine environments in developmental programming in marmosets. Evidence of developmental programming of obesity will be given, and finally, we put forward future directions and innovations for including the placenta in developmental programming of obesity in the common marmoset.

Maternal obesity increases the risk of metabolic disease and impacts renal health in offspring

Obesity, together with insulin resistance, promotes multiple metabolic abnormalities and is strongly associated with an increased risk of chronic disease including type 2 diabetes (T2D), hypertension, cardiovascular disease, non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD). The incidence of obesity continues to rise in astronomical proportions throughout the world and affects all the different stages of the lifespan. Importantly, the proportion of women of reproductive age who are overweight or obese is increasing at an alarming rate and has potential ramifications for offspring health and disease risk. Evidence suggests a strong link between the intrauterine environment and disease programming. The current review will describe the importance of the intrauterine environment in the development of metabolic disease, including kidney disease. It will detail the known mechanisms of fetal programming, including the role of epigenetic modulation. The evidence for the role of maternal obesity in the developmental programming of CKD is derived mostly from our rodent models which will be described. The clinical implication of such findings will also be discussed.

Effect of maternal high-fat diet on key components of the placental and hepatic endocannabinoid system

Maternal obesity in pregnancy has been linked to a spectrum of adverse developmental changes. Involvement of eCBs in obesity is well characterized. However, information regarding eCB physiology in obesity associated with pregnancy is sparse. This study evaluated fetomaternal hepatic, systemic, and placental eCB molecular changes in response to maternal consumption of a HFD. From ≥9 mo before conception, nonpregnant baboons ( Papio spp.) were fed a diet of either 45 (HFD; n = 11) or 12% fat or a control diet (CTR; n = 11), and dietary intervention continued through pregnancy. Maternal and fetal venous plasma samples were evaluated using liquid chromatography-mass spectrometry to quantify AEA and 2-AG. Placental, maternal and fetal hepatic tissues were analyzed using RT-PCR, Western blot, and immunohistochemistry. mRNA and protein expression of endocannabinoid receptors (CB1R and CB2R), FAAH, DAGL, MAGL, and COX-2 were determined. Statistical analyses were performed with the nonparametric Scheirer-Ray-Hare extension of the Kruskal-Wallis test to analyze the effects of diet (HFD vs. CTR), fetal sex (male vs. female), and the diet × sex interaction. Fetal weight was influenced by fetal sex but not by maternal diet. The increase in maternal weight in animals fed the HFD vs. the CTR diet approached significance ( P = 0.055). Maternal circulating 2-AG concentrations increased, and fetal circulating concentrations decreased in the HFD group, independently of fetal sex. CB1R receptor expression was detected in syncytiotrophoblasts (HFD) and the fetal endothelium (CTR and HFD). Placental CB2R protein expression was higher in males and lower in female fetuses in the HFD group. Fetal hepatic CB2R, FAAH, COX-2 (for both fetal sexes), and DAGLα (in male fetuses) protein expression decreased in the HFD group compared with the CTR group. We conclude that consumption of a HFD during pregnancy results in fetal systemic 2-AG and hepatic eCB deficiency.

Maternal Pregravid Obesity Remodels the DNA Methylation Landscape of Cord Blood Monocytes Disrupting Their Inflammatory Program

Prepregnancy maternal obesity is associated with adverse outcomes for the offspring, including increased incidence of neonatal bacterial sepsis and necrotizing enterocolitis. We recently reported that umbilical cord blood (UCB) monocytes from babies born to obese mothers generate a reduced IL-6/TNF-α response to TLR 1/2 and 4 ligands compared to those collected from lean mothers. These observations suggest altered development of the offspring's immune system, which in turn results in dysregulated function. We therefore investigated transcriptional and epigenetic differences within UCB monocytes stratified by prepregnancy maternal body mass index. We show that UCB monocytes from babies born to obese mothers generate a dampened response to LPS stimulation compared with those born to lean mothers, at the level of secreted immune mediators and transcription. Because gene expression profiles of resting UCB monocytes from both groups were comparable, we next investigated the role of epigenetic differences. Indeed, we detected stark differences in methylation levels within promoters and regulatory regions of genes involved in TLR signaling in resting UCB monocytes. Interestingly, the DNA methylation status of resting cells was highly predictive of transcriptional changes post-LPS stimulation, suggesting that cytosine methylation is one of the dominant mechanisms driving functional inadequacy in UCB monocytes obtained from babies born to obese mothers. These data highlight a potentially critical role of maternal pregravid obesity-associated epigenetic changes in influencing the function of an offspring's monocytes at birth. These findings further our understanding of mechanisms that explain the increased risk of infection in neonates born to mothers with high prepregnancy body mass index.

Metabolic abnormalities and obesity's impact on the risk for developing preeclampsia

Preeclampsia (PE), a hypertensive disorder of pregnancy, is increasing as a major contributor to perinatal and long-term morbidity of mother and offspring. PE is thought to originate from ischemic insults in the placenta driving the release of prohypertensive anti-angiogenic [soluble fms-like tyrosine kinase-1 (sFlt-1)] and proinflammatory [tumor necrosis factor-α (TNF-α)] factors into the maternal circulation. Whereas the increased incidence of PE is hypothesized to be largely due to the obesity pandemic, the mechanisms whereby obesity increases this risk are unknown. The maternal endothelium is targeted by placental and adipose tissue-derived factors like sFlt-1 and TNF-α that promote hypertension during pregnancy, resulting in vascular dysfunction and hypertension. Interestingly, not all obese pregnant women develop PE. Data suggest that obese pregnant women with the greatest metabolic abnormalities have the highest incidence of PE. Identifying obesity-related mechanisms driving hypertension in some obese pregnant women and pathways that protect normotensive obese pregnant women, may uncover novel protocols to treat PE. Metabolic abnormalities, such as increased circulating leptin, glucose, insulin, and lipids, are likely to increase the risk for PE in obese women. It is not only important to understand whether each of these metabolic factors contribute to the increased risk for PE in obesity, but also their cumulative effects. This is particularly relevant to obese pregnant women with gestational diabetes mellitus (GDM) where all of these factors are increased and the risk for PE is highest. It is speculated that these factors potentiate the anti-angiogenic and proinflammatory mechanisms of placental ischemia-induced vascular dysfunction thereby contributing to the increasing incidence of PE.

Persistent influence of maternal obesity on offspring health: Mechanisms from animal models and clinical studies

The consequences of excessive maternal weight and adiposity at conception for the offspring are now well recognized. Maternal obesity increases the risk of overweight and obesity even in children born with appropriate-for-gestational age (AGA) birth weights. Studies in animal models have employed both caloric excess and manipulation of macronutrients (especially high-fat) to mimic hypercaloric intake present in obesity. Findings from these studies show transmission of susceptibility to obesity, metabolic dysfunction, alterations in glucose homeostasis, hepatic steatosis, skeletal muscle metabolism and neuroendocrine changes in the offspring. This review summarizes the essential literature in this area in both experimental and clinical domains and focuses on the translatable aspects of these experimental studies. Moreover this review highlights emerging mechanisms broadly explaining maternal obesity-associated developmental programming. The roles of early developmental alterations and placental adaptations are also reviewed. Increasing evidence also points to changes in the epigenome and other emerging mechanisms such as alterations in the microbiome that may contribute to persistent changes in the offspring. Finally, we examine potential interventions that have been employed in clinical cohorts.

Pregnancy-driven cardiovascular maternal miR-29 plasticity in obesity

BACKGROUND

Obesity in pregnancy (MO) is a risk factor for maternal and/or fetal cardiovascular system disorders. This study evaluated maternal CVS expression of microRNA-29 family and its target molecules in MO to test the hypotheses: CVS miR-29 concentrations are increased in pregnancy and decreased in MO.

METHODS

Non-pregnant (n=4), pregnant obese (POb, n=4), and pregnant non-obese (PnOb, n=4) baboons (Papio spp.) were studied. Maternal left ventricle (LV), left atrium (LA), and aortic arch (AA) were collected at the end of gestation. Expression of MiR-29 and elastin (ELN) mRNA were quantified.

RESULTS

LA miR-29 (a, c) expression was highest in PnOb. In the LV, miR-29b expression trended lower (P=.059) for PnOb animals. ELN mRNA expression correlated positively with miR-29b expression in AA (r=.76, P=.03).

CONCLUSION

Maternal obesity diminishes miR-29 adaptation to pregnancy. Pharmacologic, tissue-specific targeting of miRNA-29 may represent a strategy for prevention and treatment of MO complications.

Maternal obesity and malnourishment exacerbate perinatal oxidative stress resulting in diabetogenic programming in F1 offspring

The effect of in-utero environment on fetal health and survival is long-lasting, and this is known as the fetal origin hypothesis. The oxidative stress state during gestation could play a pivotal role in fetal programming and development of diseases such as diabetes. In this study, we investigated the effect of intra-uterine obesity and malnutrition on oxidative stress markers in pancreatic and peripheral tissues of F1 offspring both prenatally and postnatally. Furthermore, the effect of postnatal diet on oxidative stress profile was evaluated. The results indicated that intra-uterine obesity and malnourishment significantly increased oxidative stress in F1 offspring. Moreover, the programming effect of obesity was more pronounced and protracted than malnutrition. The obesity-induced programming of offspring tissues was independent of high-caloric environment that the offspring endured; however, high-caloric diet potentiated its effect. In addition, pancreas and liver were the most affected tissues by fetal reprogramming both prenatally and postnatally. In conclusion, maternal obesity and malnutrition-induced oxidative stress could predispose offspring to insulin resistance and diabetes.

Serum Vitamin D Concentrations in Baboons (Papio spp.) during Pregnancy and Obesity

Obesity is associated with vitamin D deficiency, which can lead to serious problems during pregnancy. However, the mechanisms of the deficiency and guidelines for vitamin D supplementation during pregnancy are not established yet, and variations in environmental exposures combined with the difficulties of performing research in pregnant women are obstacles in the evaluation of vitamin D metabolism. Baboons (Papio spp.) are an excellent, well-established model for reproductive research and represent a unique opportunity to study vitamin D metabolism in a controlled environment. This study used secondary data and specimen analysis as well as a novel experimental design to evaluate pregnant and nonpregnant baboons that were or were not exposed to sunlight while they were obese and after weight reduction. Daily D3 intake was 71% higher in nonpregnant obese baboons than in their nonobese counterparts, but serum vitamin D concentrations did not differ between these populations. In addition, serum 25-hydroxyvitamin D concentrations correlated negatively with the obesity index. This report is the first to show the effect of obesity and pregnancy on vitamin D concentrations in a NHP population. These data underline the importance of adequate vitamin D supplementation in obese animals.

[Impact of maternal obesity and diabetes on placental function]

Located at the feto-maternal interface, the placenta is involved in exchange, endocrine and immune functions, which impact fetal development. In contact with the maternal environment, this organ is sensitive to metabolic disorders as over-nutrition, obesity or diabetes. The alteration of blood parameters associated with these pathologies affects placental histology, vascularization and nutrient transfers and, according to the types of troubles, induces local inflammation or hypoxia. These placental changes lead to disturbance of development and fetal growth, which increase the risk of pathologies in offspring in adulthood. The placenta thus appears as a crucial player in the fetal programming.

The impact of maternal obesity during pregnancy on offspring immunity

In the United States, approximately 64% of women of childbearing age are either overweight or obese. Maternal obesity during pregnancy is associated with a greater risk for adverse maternal-fetal outcomes. Adverse health outcomes for the offspring can persist into adulthood, increasing the incidence of several chronic conditions including cardiovascular disease, diabetes, and asthma. Since these diseases have a significant inflammatory component, these observations are indicative of perturbation of the normal development and maturation of the immune system of the offspring in utero. This hypothesis is strongly supported by data from several rodent studies. Although the mechanisms of these perturbations are not fully understood, it is thought that increased placental inflammation due to obesity may directly affect neonatal development through alterations in nutrient transport. In this review we examine the impact of maternal obesity on the neonatal immune system, and potential mechanisms for the changes observed.

Immune Mechanisms Linking Obesity and Preeclampsia

Preeclampsia (PE) is characterized by hypertension occurring after the twentieth week of pregnancy. It is a significant contributor to maternal and perinatal morbidity and mortality in developing countries and its pervasiveness is increasing within developed countries including the USA. However, the mechanisms mediating the pathogenesis of this maternal disorder and its rising prevalence are far from clear. A major theory with strong experimental evidence is that placental ischemia, resulting from inappropriate remodeling and widening of the maternal spiral arteries, stimulates the release of soluble factors from the ischemic placenta causing maternal endothelial dysfunction and hypertension. Aberrant maternal immune responses and inflammation have been implicated in each of these stages in the cascade leading to PE. Regarding the increased prevalence of this disease, it is becoming increasingly evident from epidemiological data that obesity, which is a state of chronic inflammation in itself, increases the risk for PE. Although the specific mechanisms whereby obesity increases the rate of PE are unclear, there are strong candidates including activated macrophages and natural killer cells within the uterus and placenta and activation in the periphery of T helper cells producing cytokines including TNF-α, IL-6 and IL-17 and the anti-angiogenic factor sFlt-1 and B cells producing the agonistic autoantibodies to the angiotensin type 1 receptor (AT1-aa). This review will focus on the immune mechanisms that have been implicated in the pathogenesis of hypertension in PE with an emphasis on the potential importance of inflammatory factors in the increased risk of developing PE in obese pregnancies.

The effect of maternal Inflammation on foetal programming of metabolic disease

Maternal obesity during pregnancy increases the child's risk of developing obesity and obesity-related diseases later in life. Key components in foetal programming of metabolic risk remain to be identified; however, chronic low-grade inflammation associated with obesity might be responsible for metabolic imprinting in the offspring. We have therefore surveyed the literature to evaluate the role of maternal obesity-induced inflammation in foetal programming of obesity and related diseases. The literature on this topic is limited, so this review also includes animal models where maternal inflammation is mimicked by single injections with lipopolysaccharide (LPS). An LPS challenge results in an immunological response that resembles the obesity-induced immune profile, although LPS injections provoke a stronger response than the subclinical obesity-associated response. Maternal LPS or cytokine exposures result in increased adiposity and impaired metabolic homeostasis in the offspring, similar to the phenotype observed after exposure to maternal obesity. The cytokine levels might be specifically important for the metabolic imprinting, as cytokines are both transferable from maternal to foetal circulation and have the capability to modulate placental nutrient transfer. However, the immune response associated with obesity is moderate and therefore potentially weakened by the pregnancy-driven immune modulation, dominated by anti-inflammatory Treg and Th2 cells. We know from other low-grade inflammatory diseases, such as rheumatoid arthritis, that pregnancy can improve disease state. If pregnancy is also capable of suppressing the obesity-associated inflammation, the immunological markers might be less likely to affect metabolic programming in the developing foetus than otherwise implied.

Placental contribution to nutritional programming of health and diseases: epigenetics and sexual dimorphism

The recent and rapid worldwide increase in non-communicable diseases challenges the assumption that genetic factors are the primary contributors to such diseases. A new concept of the ‘developmental origins of health and disease’ (DOHaD) is at stake and therefore requires a paradigm shift. Maternal obesity and malnutrition predispose offspring to develop metabolic syndrome, a vicious cycle leading to transmission to subsequent generation(s), with differences in response and susceptibility according to the sex of the individual. The placenta is a programming agent of adult health and disease. Adaptations of placental phenotype in response to maternal diet and metabolic status alter fetal nutrient supply. This implies important epigenetic changes that are, however, still poorly documented in DOHaD studies, particularly concerning overnutrition. The aim of this review is to discuss the emerging knowledge on the relationships between the effect of maternal nutrition or metabolic status on placental function and the risk of diseases later in life, with a specific focus on epigenetic mechanisms and sexual dimorphism. Explaining the sex-specific causal variables and how males versus females respond and adapt to environmental perturbations should help physicians and patients to anticipate disease susceptibility.

Conjugated linoleic Acid supplementation during pregnancy and lactation reduces maternal high-fat-diet-induced programming of early-onset puberty and hyperlipidemia in female rat offspring

A maternal high-fat (HF) diet during pregnancy and lactation can result in adverse metabolic and reproductive outcomes in female offspring independent of postnatal diet. Interventions during critical windows of developmental plasticity may prevent developmental programming in offspring. The effects of maternal supplementation with the anti-inflammatory lipid conjugated linoleic acid (CLA) on early-onset puberty, metabolic dysfunction, and estrous cycle dysfunction was assessed. Sprague-Dawley rats were randomly assigned to a purified control diet (CD; 10% kcal from fat), CD with CLA (CLA; 10% kcal from fat, 1% CLA), HF (45% kcal from fat) or HF with CLA (HFCLA; 45% kcal from fat, 1% CLA). Diets were fed ad libitum for 10 days prior to time mating and throughout gestation and lactation. Offspring plasma/tissues were taken at Day 24 (prepubertal) or Day 150 (adult). Puberty was assessed from Day 26 and estrous cycle from Day 128. Female offspring from HF mothers had lower birth weights but by Postnatal Day 24 had exhibited catch-up growth concomitant with increased fat mass, hyperleptinemia, and dyslipidemia. Maternal CLA supplementation reversed these effects. Early-onset puberty was only observed in HF offspring; this was reversed in HFCLA offspring. In adulthood, despite no evidence of glucose intolerance or altered insulin sensitivity, HF offspring displayed increased fat mass, dyslipidemia, disrupted estrous cyclicity. and hyperleptinemia; this was reversed by maternal CLA supplementation. Data presented in this study demonstrate the importance of diet in women of reproductive age and during pregnancy on reproductive and metabolic parameters in their offspring and that supplementation with CLA during critical windows of development may represent a therapeutic strategy in the prevention of early-life programming of metabolic and reproductive dysfunction.

RNA-seq analysis of the rat placentation site reveals maternal obesity-associated changes in placental and offspring thyroid hormone signaling

INTRODUCTION

In animal models, maternal obesity (OB) leads to augmented risk of offspring OB. While placental function is influenced by maternal habitus, the effect of maternal obesity on the interacting zones of the placenta [the labyrinth (LZ), junctional (JZ) and metrial gland (MG)] remains unknown.

METHODS

Using a rat maternal obesity model, we conducted transcriptomic profiling of the utero-placental compartments and fetal liver (FL) at dpc 18.5, in conjunction with analyses of mRNA expression of key thyroid hormone (TH) signaling genes in the placenta, fetus and weanling offspring.

RESULTS AND DISCUSSION

Gene expression analysis of placenta and offspring revealed that each utero-placental compartment responds distinctly to maternal OB with changes in inflammatory signaling, lipid metabolism and hormone stimulus being the predominant effects. OB-induced alterations in 17 genes were confirmed by qPCR, including reductions in thyrotropin-releasing hormone (Trh) in JZ. We further characterized mRNA and protein expression of TH signaling regulators including deiodinases (Dio), TH receptors (Tr), and downstream targets (uncoupling proteins (Ucp)). A concerted down-regulation of multiple facets of thyroid hormone signaling in the JZ and FL was observed. JZ expression of thyroid hormone signaling components Trh, Dio2, Trα, and Ucp2 were negatively associated with maternal leptin. mRNA expression of TRH, TRβ and UCP1 were also decreased in term placenta from OB women. Finally, our studies identified persistent impairments in expression of TH related genes in tissues from offspring of obese dams.

CONCLUSIONS

The role of lower placental thyroid expression is worthy of further study as a possible pathway that leads to low energy metabolism and obesity in animals born to obese mothers.

Early developmental conditioning of later health and disease: physiology or pathophysiology?

Extensive experimental animal studies and epidemiological observations have shown that environmental influences during early development affect the risk of later pathophysiological processes associated with chronic, especially noncommunicable, disease (NCD). This field is recognized as the developmental origins of health and disease (DOHaD). We discuss the extent to which DOHaD represents the result of the physiological processes of developmental plasticity, which may have potential adverse consequences in terms of NCD risk later, or whether it is the manifestation of pathophysiological processes acting in early life but only becoming apparent as disease later. We argue that the evidence suggests the former, through the operation of conditioning processes induced across the normal range of developmental environments, and we summarize current knowledge of the physiological processes involved. The adaptive pathway to later risk accords with current concepts in evolutionary developmental biology, especially those concerning parental effects. Outside the normal range, effects on development can result in nonadaptive processes, and we review their underlying mechanisms and consequences. New concepts concerning the underlying epigenetic and other mechanisms involved in both disruptive and nondisruptive pathways to disease are reviewed, including the evidence for transgenerational passage of risk from both maternal and paternal lines. These concepts have wider implications for understanding the causes and possible prevention of NCDs such as type 2 diabetes and cardiovascular disease, for broader social policy and for the increasing attention paid in public health to the lifecourse approach to NCD prevention.

High fat and/or high salt intake during pregnancy alters maternal meta-inflammation and offspring growth and metabolic profiles

A high intake of fat or salt during pregnancy perturbs placental function, alters fetal development, and predisposes offspring to metabolic disease in adult life. Despite its relevance to modern dietary habits, the developmental programming effects of excessive maternal fat and salt, fed in combination, have not been examined. We investigated the effects of moderately high maternal fat and/or salt intake on maternal metainflammation and its consequences on fetal and weanling growth and metabolic profile. Female Sprague–Dawley rats were fed a standard control diet (CD), 4% salt diet (SD), 45% fat diet (HF) or 4% salt/45% fat combined diet (HFSD) 3 weeks prior to and throughout pregnancy and lactation. Plasma and tissue samples were collected at day 18 of pregnancy from mother and fetus, and at postnatal day 24 in weanlings. Markers of adipose tissue inflammation, macrophage infiltration, lipogenesis, nutrient transport, and storage were altered in pregnant dams receiving high‐fat and/or ‐salt diets. This was accompanied by increased fat mass in high‐fat groups and differential hepatic lipid and glucose homeostasis. Offspring of high fat‐fed mothers had reduced fetal weight, displayed catch‐up growth, increased fat mass, and altered metabolic profiles at weaning. Maternal diets high in fat and/or salt affect maternal metabolic parameters, fetal growth and development, metabolic status, and adipoinsular axis in the weanling. Results presented here highlight the importance of diet in expectant mothers or women considering pregnancy. Furthermore, the potential for maternal nutritional intervention strategies may be employed to modify the metabolic disease risk in adult offspring during later life.

We investigated the effects of moderately high maternal fat and/or salt intake on maternal metainflammation and its consequences on fetal and weanling growth and metabolic profile. Maternal diets high in fat and/or salt affect maternal metabolic parameters, fetal growth and development, metabolic status, and adipoinsular axis in the weanling. Results presented here highlight the importance of diet in expectant mothers or women considering pregnancy.

Maternal diet-induced obesity and offspring cardiovascular health

It is widely recognized that environmental insults during adulthood including smoking, lack of exercise and a poor diet increases an individual's risk of cardiovascular disease (CVD). However, research initiated over the last two decades has highlighted that our risk of CVD can be programmed following adverse exposures during early development. Such adverse exposures may include, undernutrition, placental insufficiency, hypoxia, overnutrition and obesity. This review aims to address the current Western obesity crisis by addressing the long-term impact of maternal overnutrition and obesity on the offspring's future risk of CVD. Although current human studies have observed the presence of adverse CVD markers in children born to obese mothers, animal models have proved vital in understanding the underlying mechanisms involved. Mechanisms suggested to be involved in the programming of CVD in the offspring include increased oxidative stress, inflammation, lipotoxicity and epigenetics. CVD remains the greatest cause of death worldwide, therefore further understanding of the mechanisms mediating these effects is important in the development of intervention strategies.

Overweight and Obesity before, during and after Pregnancy: Part 1: Pathophysiology, Molecular Biology and Epigenetic Consequences

Overweight and obesity before conception as well as excessive weight gain during pregnancy are associated with endocrinological changes of mother and fetus. Insulin resistance physiologically increases during pregnancy, additional obesity further increases insulin resistance. In combination with reduced insulin secretion this leads to gestational diabetes which may develop into type-2-diabetes. The adipose tissue produces TNF-alpha, interleukins and leptin and upregulates these adipokines. Insulin resistance and obesity induce inflammatory processes and vascular dysfunction, which explains the increased rate of pregnancy-related hypertension and pre-eclampsia in obese pregnant women. Between 14 and 28 gestational weeks, the fetal adipose tissue is generated and the number of fat lobules is determined. Thereafter, an increase in adipose tissue is arranged by an enlargement of the lobules (hypertrophy), or even an increase in the number of fat cells (hyperplasia). Human and animal studies have shown that maternal obesity "programmes" the offspring for further obesity and chronic disease. Pregnant women, midwives, physicians and health care politicians should be better informed about prevention, pathophysiological mechanisms, and the burden for society caused by obesity before, during and after pregnancy.

Understanding the control of ingestive behavior in primates

This article is part of a Special Issue "Energy Balance". Ingestive behavior in free-ranging populations of nonhuman primates is influenced by resource availability and social group organization and provides valuable insight on the evolution of ecologically adaptive behaviors and physiological systems. As captive populations were established, questions regarding proximate mechanisms that regulate food intake in these animals could be more easily addressed. The availability of these captive populations has led to the use of selected species to understand appetite control or metabolic physiology in humans. Recognizing the difficulty of quantitating food intake in free-ranging groups, the use of captive, singly-housed animals provided a distinct advantage though, at the same time, produced a different social ecology from the animals' natural habitat. However, the recent application of novel technologies to quantitate caloric intake and energy expenditure in free-feeding, socially housed monkeys permits prospective studies that can accurately define how food intake changes in response to any number of interventions in the context of a social environment. This review provides an overview of studies examining food intake using captive nonhuman primates organized into three areas: a) neurochemical regulation of food intake in nonhuman primates; b) whether exposure to specific diets during key developmental periods programs differences in diet preferences or changes the expression of feeding related neuropeptides; and c) how psychosocial factors influence appetite regulation. Because feeding patterns are driven by more than just satiety and orexigenic signals, appreciating how the social context influences pattern of feeding in nonhuman primates may be quite informative for understanding the biological complexity of feeding in humans.

Mechanisms by which maternal obesity programs offspring for obesity: evidence from animal studies

Maternal obesity can profoundly affect offspring phenotype and predisposition to obesity and metabolic disease. Carefully controlled studies in precocial and altricial mammalian species provide insights into the involved mechanisms. These include programming of hypothalamic appetite-regulating centers to increase orexigenic relative to anorexigenic drive; increasing maternal, fetal, and offspring adrenal and peripheral tissue glucocorticoid production; and increasing maternal oxidative stress. Outcomes often show offspring sex differences that may play a role in the differential susceptibility of males and females to later-life obesity and other related metabolic diseases.

Maternal nutrition and risk of obesity in offspring: the Trojan horse of developmental plasticity

Mammalian embryos have evolved to adjust their organ and tissue development in response to an atypical environment. This adaptation, called phenotypic plasticity, allows the organism to thrive in the anticipated environment in which the fetus will emerge. Barker and colleagues proposed that if the environment in which the fetus emerges differs from that in which it develops, phenotypic plasticity may provide an underlying mechanism for disease. Epidemiological studies have shown that humans born small- or large-for-gestational-age, have a higher likelihood of developing obesity as adults. The amount and quality of food that the mother consumes during gestation influences birth weight, and therefore susceptibility of progeny to disease in later life. Studies in experimental animals support these observations, and find that obesity occurs as a result of maternal nutrient-restriction during gestation, followed by rapid compensatory growth associated with ad libitum food consumption. Therefore, obesity associated with maternal nutritional restriction has a developmental origin. Based on this phenomenon, one might predict that gestational exposure to a westernized diet would protect against future obesity in offspring. However, evidence from experimental models indicates that, like maternal dietary restriction, maternal consumption of a westernized diet during gestation and lactation interacts with an adult obesogenic diet to induce further obesity. Mechanistically, restriction of nutrients or consumption of a high fat diet during gestation may promote obesity in progeny by altering hypothalamic neuropeptide production and thereby increasing hyperphagia in offspring. In addition to changes in food intake these animals may also direct energy from muscle toward storage in adipose tissue. Surprisingly, generational inheritance studies in rodents have further indicated that effects on body length, body weight, and glucose tolerance appear to be propagated to subsequent generations. Together, the findings discussed herein highlight the concept that maternal nutrition contributes to a legacy of obesity. Thus, ensuring adequate supplies of a complete and balanced diet during and after pregnancy should be a priority for public health worldwide. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

Mortality in captive baboons (Papio spp.): a-23-year study

BACKGROUND

We report the causes of mortality for 4350 captive baboons that died or were euthanized due to natural causes during a 23 year period at the Southwest National Primate Research Center.

METHODS

Necropsy records were retrieved and reviewed to determine a primary cause of death or indication for euthanasia. Data was evaluated for morphological diagnosis, organ system, and etiology.

RESULTS

The 20 most common morphologic diagnoses accounted for 76% of the cases, including stillborn (10.8%); colitis (8.6%); hemorrhage (8.4%); ulcer (5.2%); seizures (4.7%); pneumonia (4.2%); inanition (4.1%); dermatitis (3.8%); spondylosis (3.3%); and amyloidosis (3.0%). The digestive system was most frequently involved (21.3%), followed by the urogenital (20.3%), cardiovascular (12.2%), and multisystem disease (10.3%). An etiology was not identified in approximately one-third of cases. The most common etiologies were trauma (14.8%), degenerative (9.5%), viral (8.7%), and neoplastic/proliferative (7.0%).

CONCLUSION

This information should be useful for individuals working with baboons.