Maternal diet-induced obesity and offspring cardiovascular health

Voluntary Wheel Running Reduces Cardiometabolic Risks in Female Offspring Exposed to Lifelong High-Fat, High-Sucrose Diet

PURPOSE

Maternal and postnatal overnutrition has been linked to an increased risk of cardiometabolic diseases in offspring. This study investigated the impact of adult-onset voluntary wheel running to counteract cardiometabolic risks in female offspring exposed to a life-long high-fat, high-sucrose (HFHS) diet.

METHODS

Dams were fed either an HFHS or a low-fat, low-sucrose (LFLS) diet starting from 8 wk before pregnancy and continuing throughout gestation and lactation. Offspring followed their mothers' diets. At 15 wk of age, they were divided into sedentary (Sed) or voluntary wheel running (Ex) groups, resulting in four groups: LFLS/Sed ( n = 10), LFLS/Ex ( n = 5), HFHS/Sed ( n = 6), HFHS/Ex ( n = 5). Cardiac function was assessed at 25 wk, with tissue collection at 26 wk for mitochondrial respiratory function and protein analysis. Data were analyzed using two-way ANOVA.

RESULTS

Although maternal HFHS diet did not affect the offspring's body weight at weaning, continuous HFHS feeding postweaning resulted in increased body weight and adiposity, irrespective of the exercise regimen. HFHS/Sed offspring showed increased left ventricular wall thickness and elevated expression of enzymes involved in fatty acid transport (CD36, FABP3), lipogenesis (DGAT), glucose transport (GLUT4), oxidative stress (protein carbonyls, nitrotyrosine), and early senescence markers (p16, p21). Their cardiac mitochondria displayed lower oxidative phosphorylation (OXPHOS) efficiency and reduced expression of OXPHOS complexes and fatty acid metabolism enzymes (ACSL5, CPT1B). However, HFHS/Ex offspring mitigated these effects, aligning more with LFLS/Sed offspring.

CONCLUSIONS

Adult-onset voluntary wheel running effectively counteracts the detrimental cardiac effects of a lifelong HFHS diet, improving mitochondrial efficiency, reducing oxidative stress, and preventing early senescence. This underscores the significant role of physical activity in mitigating diet-induced cardiometabolic risks.

Age of Juice Introduction and Cardiometabolic Outcomes in Middle Childhood

BACKGROUND

The American Academy of Pediatrics recommends juice introduction after 12 months of age. Juice consumption has been linked to childhood obesity and cardiometabolic risk.

OBJECTIVES

To examine the prospective relationship between the age of juice introduction and primary and secondary cardiometabolic outcomes in middle childhood.

METHODS

Parents reported the age of juice introduction on Upstate KIDS questionnaires completed between 4 and 18 months. The quantity and type of juice introduced were not measured. Anthropometry, blood pressure (BP), and arterial stiffness by pulse wave velocity (PWV) were measured for 524 children (age, 8-10 y) at study visits (2017-2019). Age- and gender-adjusted z-scores were calculated using the Centers for Disease Control and Prevention reference for anthropometrics. Plasma lipids, hemoglobin A1c (HbA1c), and C-reactive protein (CRP) in a subset of children were also measured (n = 248). Associations between age at juice introduction (categorized as <6, 6 to <12, ≥12 months), and outcomes were estimated using mean differences and odds ratios, applying generalized estimating equations to account for correlations between twins.

RESULTS

Approximately 18% of children were introduced to juice at <6 months, 52% between 6 and <12 months, and 30% ≥ 12 months of age. Children who were introduced to juice before 6 months had higher systolic BP (3.13 mmHg; 95% confidence interval [CI]: 0.52, 5.74), heart rate (4.46 bpm; 95% CI: 1.05, 7.87), and mean arterial pressure (2.08 mmHg; 95% CI: 0.15, 4.00) compared with those introduced ≥12 months after covariate adjustment including sociodemographic factors and maternal prepregnancy body mass index. No adjusted differences in anthropometry, lipids, HbA1c, and CRP levels were found.

CONCLUSIONS

Early juice introduction during infancy was associated with higher systolic BP, heart rate, and mean arterial pressure in middle childhood. This trial was registered at clinicaltrials.gov as NCT03106493 (https://clinicaltrials.gov/study/NCT03106493?term=upstate%20KIDS&rank=1).

A High-Sugar Diet Consumption, Metabolism and Health Impacts with a Focus on the Development of Substance Use Disorder: A Narrative Review

Carbohydrates are important macronutrients in human and rodent diet patterns that play a key role in crucial metabolic pathways and provide the necessary energy for proper body functioning. Sugar homeostasis and intake require complex hormonal and nervous control to proper body energy balance. Added sugar in processed food results in metabolic, cardiovascular, and nervous disorders. Epidemiological reports have shown enhanced consumption of sweet products in children and adults, especially in reproductive age and in pregnant women, which can lead to the susceptibility of offspring's health to diseases in early life or in adulthood and proneness to mental disorders. In this review, we discuss the impacts of high-sugar diet (HSD) or sugar intake during the perinatal and/or postnatal periods on neural and behavioural disturbances as well as on the development of substance use disorder (SUD). Since several emotional behavioural disturbances are recognized as predictors of SUD, we also present how HSD enhances impulsive behaviour, stress, anxiety and depression. Apart from the influence of HSD on these mood disturbances, added sugar can render food addiction. Both food and addictive substances change the sensitivity of the brain rewarding neurotransmission signalling. The results of the collected studies could be important in assessing sugar intake, especially via maternal dietary patterns, from the clinical perspective of SUD prevention or pre-existing emotional disorders. Methodology: This narrative review focuses on the roles of a high-sugar diet (HSD) and added sugar in foods and on the impacts of glucose and fructose on the development of substance use disorder (SUD) and on the behavioural predictors of drugs abuse. The literature was reviewed by two authors independently according to the topic of the review. We searched the PubMed and Scopus databases and Multidisciplinary Digital Publishing Institute open access scientific journals using the following keyword search strategy depending on the theme of the chapter: "high-sugar diet" OR "high-carbohydrate diet" OR "sugar" OR "glucose" OR "fructose" OR "added sugar" AND keywords. We excluded inaccessible or pay-walled articles, abstracts, conference papers, editorials, letters, commentary, and short notes. Reviews, experimental studies, and epidemiological data, published since 1990s, were searched and collected depending on the chapter structure. After the search, all duplicates are thrown out and full texts were read, and findings were rescreened. After the selection process, appropriate papers were included to present in this review.

Gestational Nutrition as a Predisposing Factor to Obesity Onset in Offspring: Role for Involvement of Epigenetic Mechanism

Maternal lifestyle has been implicated as a predisposing factor in the development of metabolic disorders in adulthood. This lifestyle includes the immediate environment, physical activity and nutrition. Maternal nutrition has direct influence on the developmental programming through biochemical alterations and can lead to modifications in the fetal genome through epigenetic mechanisms. Imbalance in basic micro or macro nutrients due to famine or food deficiency during delicate gestational periods can lead to onset of metabolic syndrome including obesity. A major example is the Dutch famine which led to a serious metabolic disorder in adulthood of affected infants. Notably due to gene variants, individualized responses to nutritional deficiencies are unconventional, therefore intensifying the need to study nutritional genomics during fetal programming. Epigenetic mechanisms can cause hereditary changes without changing the DNA sequence; the major mechanisms include small non-coding RNAs, histone modifications and most stable of all is DNA methylation. The significance association between obesity and DNA methylation is through regulation of genes implicated in lipid and glucose metabolism either directly or indirectly by hypomethylation or hypermethylation. Examples include CPT1A, APOA2, ADRB3 and POMC. Any maternal exposure to malnutrition or overnutrition that can affect genes regulating major metabolic pathways in the fetus, will eventually cause underlying changes that can predispose or cause the onset of metabolic disorder in adulthood. In this review, we examined the interaction between nutrition during gestation and epigenetic programming of metabolic syndrome.

Epigenetics in the Uterine Environment: How Maternal Diet and ART May Influence the Epigenome in the Offspring with Long-Term Health Consequences

The societal burden of non-communicable disease is closely linked with environmental exposures and lifestyle behaviours, including the adherence to a poor maternal diet from the earliest preimplantation period of the life course onwards. Epigenetic variations caused by a compromised maternal nutritional status can affect embryonic development. This review summarises the main epigenetic modifications in mammals, especially DNA methylation, histone modifications, and ncRNA. These epigenetic changes can compromise the health of the offspring later in life. We discuss different types of nutritional stressors in human and animal models, such as maternal undernutrition, seasonal diets, low-protein diet, high-fat diet, and synthetic folic acid supplement use, and how these nutritional exposures epigenetically affect target genes and their outcomes. In addition, we review the concept of thrifty genes during the preimplantation period, and some examples that relate to epigenetic change and diet. Finally, we discuss different examples of maternal diets, their effect on outcomes, and their relationship with assisted reproductive technology (ART), including their implications on epigenetic modifications.

Excess Vitamins or Imbalance of Folic Acid and Choline in the Gestational Diet Alter the Gut Microbiota and Obesogenic Effects in Wistar Rat Offspring

Excess vitamin intake during pregnancy leads to obesogenic phenotypes, and folic acid accounts for many of these effects in male, but not in female, offspring. These outcomes may be modulated by another methyl nutrient choline and attributed to the gut microbiota. Pregnant Wistar rats were fed an AIN-93G diet with recommended vitamin (RV), high 10-fold multivitamin (HV), high 10-fold folic acid with recommended choline (HFol) or high 10-fold folic acid without choline (HFol-C) content. Male and female offspring were weaned to a high-fat RV diet for 12 weeks post-weaning. Removing choline from the HFol gestational diet resulted in obesogenic phenotypes that resembled more closely to HV in male and female offspring with higher body weight, food intake, glucose response to a glucose load and body fat percentage with altered activity, concentrations of short-chain fatty acids and gut microbiota composition. Gestational diet and sex of the offspring predicted the gut microbiota differences. Differentially abundant microbes may be important contributors to obesogenic outcomes across diet and sex. In conclusion, a gestational diet high in vitamins or imbalanced folic acid and choline content contributes to the gut microbiota alterations consistent with the obesogenic phenotypes of in male and female offspring.

Dyslipidemia, insulin resistance, and impairment of placental metabolism in the offspring of obese mothers

Obesity is a chronic condition associated with dyslipidemia and insulin resistance. Here, we show that the offspring of obese mothers are dyslipidemic and insulin resistant from the outset.Maternal and cord blood and placental tissues were collected following C-section at term. Patients were grouped as being normal weight (NW, BMI = 18-24.9) or obese (OB, BMI ≥ 30), and separated by fetal sex. We measured plasma lipids, insulin, and glucose in maternal and cord blood. Insulin resistance was quantified using the HOMA-IR. Placental markers of lipid and energy metabolism and relevant metabolites were measured by western blot and metabolomics, respectively.For OB women, total cholesterol was decreased in both maternal and cord blood, while HDL was decreased only in cord blood, independent of sex. In babies born to OB women, cord blood insulin and insulin resistance were increased. Placental protein expression of the energy and lipid metabolism regulators PGC1α, and SIRT3, ERRα, CPT1α, and CPT2 decreased with maternal obesity in a sex-dependent manner (P < 0.05). Metabolomics showed lower levels of acylcarnitines C16:0, C18:2, and C20:4 in OB women's placentas, suggesting a decrease in β-oxidation. Glutamine, glutamate, alpha-ketoglutarate (αKG), and 2-hydroxyglutarate (2-HG) were increased, and the glutamine-to-glutamate ratio decreased (P < 0.05), in OB placentas, suggesting induction of glutamate into αKG conversion to maintain a normal metabolic flux.Newly-born offspring of obese mothers begin their lives dyslipidemic and insulin resistant. If not inherited genetically, such major metabolic perturbations might be explained by abnormal placental metabolism with potential long-term adverse consequences for the offspring's health and wellbeing.

Environmental Alterations during Embryonic Development: Studying the Impact of Stressors on Pluripotent Stem Cell-Derived Cardiomyocytes

Non-communicable diseases (NCDs) sauch as diabetes, obesity and cardiovascular diseases are rising rapidly in all countries world-wide. Environmental maternal factors (e.g., diet, oxidative stress, drugs and many others), maternal illnesses and other stressors can predispose the newborn to develop diseases during different stages of life. The connection between environmental factors and NCDs was formulated by David Barker and colleagues as the Developmental Origins of Health and Disease (DOHaD) hypothesis. In this review, we describe the DOHaD concept and the effects of several environmental stressors on the health of the progeny, providing both animal and human evidence. We focus on cardiovascular diseases which represent the leading cause of death worldwide. The purpose of this review is to discuss how in vitro studies with pluripotent stem cells (PSCs), such as embryonic and induced pluripotent stem cells (ESC, iPSC), can underpin the research on non-genetic heart conditions. The PSCs could provide a tool to recapitulate aspects of embryonic development “in a dish”, studying the effects of environmental exposure during cardiomyocyte (CM) differentiation and maturation, establishing a link to molecular mechanism and epigenetics.

The metabolic syndrome in pregnancy and its association with child telomere length

AIMS/HYPOTHESIS

The aim of this study was to determine whether presence of the metabolic syndrome in pregnancy associates with child telomere length or child anthropometry (weight, BMI) and BP, measured at 10 years of age.

METHODS

The Screening for Pregnancy Endpoints study (SCOPE) was a multicentre, international prospective cohort of nulliparous pregnant women recruited from Australia, New Zealand, Ireland and the UK (N = 5628). The current analysis is a 10 year follow-up of SCOPE pregnant women and their children, from the Australian cohort. Clinical data collected at 14-16 weeks' gestation during the SCOPE study were used to diagnose the metabolic syndrome using IDF criteria. Telomere length, a biomarker of ageing, was assessed by quantitative PCR from children's saliva collected at 10 years of age.

RESULTS

In women who completed follow-up (n = 255), 20% had the metabolic syndrome in pregnancy. After adjusting for a range of confounders, children of mothers who had the metabolic syndrome in pregnancy had 14% shorter telomeres than children of mothers without the metabolic syndrome in pregnancy (mean difference -0.36 [95% CI -0.74, 0.01]). Height- and weight-for-age, and BMI z scores were similar in children of mothers who did and did not have the metabolic syndrome during pregnancy.

CONCLUSIONS/INTERPRETATION

Children of mothers who had the metabolic syndrome in pregnancy have shorter telomeres, a biomarker of accelerated ageing. These findings warrant further studies in larger cohorts of children, as well as investigations into whether telomere length measured in cord blood associates with telomere length in childhood.

The impact of maternal nutrition on offspring's risk of non-communicable diseases in adulthood: a systematic review

Background

A growing body of evidence suggests the impact of maternal nutrition plays a role in determining offspring's risk of non-communicable diseases (NCDs), including heart disease (CVD), type 2 diabetes (T2DM), cancer and chronic obstructive pulmonary diseases (COPD). We conducted a systematic review to investigate this relationship.

Methods

We systematically searched CINAHL, Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, Database of Abstracts of Reviews of Effects, MEDLINE, EMBASE, Web of Science Core Collection and Global Health for papers published before May 2016 (PROSPERO: CRD42016039244, CRD42016039247). Included studies examined the impact of maternal nutrition (diet, vitamin status and weight) on adult offspring's NCD outcomes.

Results

Of 23 501 identified citations, 20 met our inclusion criteria. Heterogeneity of papers required narrative synthesis. Included studies involved 1 939 786 participants. CVD: Four papers examined maternal exposure to famine during gestation, 3 identified a resulting increased risk of CVD in offspring. Five identified an increased risk of offspring CVD with increasing maternal weight. T2DM: Six studies investigated maternal exposure to famine during gestation; three identified an increase in offspring's T2DM risk. Three found no increased risk; two of these were in circumstances where famine states persisted beyond pregnancy. Three papers found an increased risk of T2DM in offspring with increasing maternal BMI. CANCER: Four papers investigated maternal famine exposure during pregnancy - two identified a reduced risk of cancer in male offspring, and two an increased risk in female offspring. COPD: One study found low maternal vitamin D status was associated with reduced use of asthma medication.

Conclusions

While there are indications that exposure to both famine (particularly when coupled with exposure to nutritional excess after birth) and maternal overweight during pregnancy is associated with offspring's risk of CVD, T2DM and cancer, currently there is a lack of evidence to confirm this relationship. Despite the lack of conclusive evidence, these finding hold important research and policy implications for a lifecycle approach to the prevention of NCDs.

Parental Dietary Protein Source and the Role of CMKLR1 in Determining the Severity of Dahl Salt-Sensitive Hypertension

Studies from our laboratory have revealed an important role for the maternal diet and the dietary protein source in the development of hypertension and renal injury in Dahl salt-sensitive (SS) rats. The current study sought to compare salt-induced hypertension, renal damage, and immune cell infiltration in the offspring of breeders fed either a casein- or gluten-based diet, with the hypothesis that offspring from gluten-fed breeders would fail to develop these SS phenotypes. When fed identical diets post-weaning, the F1 generation gluten offspring demonstrated lower mean arterial pressure (149.1±3.1 versus 162.5±5.8 mm Hg), albuminuria (166.2±34.6 versus 250.9±27.8 mg/day), and outer medullary protein casting (7.4±0.8% versus 13.1±1.3%) in response to high salt compared with the casein offspring (n=9-11). The gluten offspring also had fewer CD45+ leukocytes, CD11b/c+ monocytes/macrophages, CD3+ T cells, and CD45R+ B cells infiltrating the kidney. Analysis of the F2 generation gluten offspring also exhibited lower mean arterial pressure and renal damage compared with rats born from casein breeders (n=7-9), with no difference in renal immune cell infiltration. CMKLR1-receptor for the novel prohypertensive adipokine chemerin-was found via polymerase chain reaction array to be significantly upregulated (2.99-fold) in renal T cells isolated from F2 offspring of casein-fed versus gluten-fed parents. Furthermore, CMKLR1 inhibition via α-NETA (2-[α-naphthoyl] ethyltrimethylammonium iodide) treatment significantly attenuated renal immune cell infiltration, hypertension, and renal damage in SS rats fed high salt. Together, these data demonstrate the influence of the parental diet in determining the salt-induced hypertension, renal damage, and inflammatory phenotype of the offspring.

Effects of high-fat diets on fetal growth in rodents: a systematic review

BACKGROUND

Maternal nutrition during pregnancy has life-long consequences for offspring. However, the effects of maternal overnutrition and/ or obesity on fetal growth remain poorly understood, e.g., it is not clear why birthweight is increased in some obese pregnancies but not in others. Maternal obesity is frequently studied using rodents on high-fat diets, but effects on fetal growth are inconsistent. The purpose of this review is to identify factors that contribute to reduced or increased fetal growth in rodent models of maternal overnutrition.

METHODS

We searched Web of Science and screened 2173 abstracts and 328 full texts for studies that fed mice or rats diets providing ~ 45% or ~ 60% calories from fat for 3 weeks or more prior to pregnancy. We identified 36 papers matching the search criteria that reported birthweight or fetal weight.

RESULTS

Studies that fed 45% fat diets to mice or 60% fat diets to rats generally did not show effects on fetal growth. Feeding a 45% fat diet to rats generally reduced birth and fetal weight. Feeding mice a 60% fat diet for 4-9 weeks prior to pregnancy tended to increase in fetal growth, whereas feeding this diet for a longer period tended to reduce fetal growth.

CONCLUSIONS

The high-fat diets used most often with rodents do not closely match Western diets and frequently reduce fetal growth, which is not a typical feature of obese human pregnancies. Adoption of standard protocols that more accurately mimic effects on fetal growth observed in obese human pregnancies will improve translational impact in this field.

Nutrigenetics, epigenetics and gestational diabetes: consequences in mother and child

Gestational Diabetes Mellitus (GDM) is the most common metabolic condition during pregnancy and may result in short- and long-term complications for both mother and offspring. The complexity of phenotypic outcomes seems influenced by genetic susceptibility, nutrient-gene interactions and lifestyle interacting with clinical factors. There is strong evidence that not only the adverse genetic background but also the epigenetic modifications in response to nutritional and environmental factors could influence the maternal hyperglycemia in pregnancy and the foetal metabolic programming. In this view, the correlation between epigenetic modifications and their transgenerational effects represents a very interesting field of study. The present review gives insight into the role of gene variants and their interactions with nutrients in GDM. In addition, we provide an overview of the epigenetic changes and their role in the maternal-foetal transmission of chronic diseases. Overall, the knowledge of epigenetic modifications induced by an adverse intrauterine and perinatal environment could shed light on the potential pathophysiological mechanisms of long-term disease development in the offspring and provide useful tools for their prevention.

Influence of dietary protein on Dahl salt-sensitive hypertension: a potential role for gut microbiota

High blood pressure affects 1.39 billion adults across the globe and is the leading preventable cause of death worldwide. Hypertension is a multifaceted disease with known genetic and environmental factors contributing to its progression. Our studies utilizing the Dahl salt-sensitive (SS) rat have demonstrated the remarkable influence of dietary protein and maternal environment on the development of hypertension and renal damage in response to high salt. There is growing interest in the relationship between the microbiome and hypertension, with gut dysbiosis being correlated to a number of pathologies. This review summarizes the current literature regarding the interplay among dietary protein, the gut microbiota, and hypertension. These studies may provide insight into the effects we have observed between diet and hypertension in Dahl SS rats and, we hope, lead to new perspectives where potential dietary interventions or microbiota manipulations could serve as plausible therapies for hypertension.

Diet-induced obesity reduces core body temperature across the estrous cycle and pregnancy in the rat

Obesity during pregnancy causes adverse maternal and fetal health outcomes and programs offspring for adult-onset diseases, including cardiovascular disease. Obesity also disrupts core body temperature (T_c) regulation in nonpregnant rodents; however, it is unknown whether obesity alters normal maternal T_c adaptations to pregnancy. Since T_c is influenced by the circadian system, and both obesity and pregnancy alter circadian biology, it was hypothesized that obesity disrupts the normal rhythmic patterns of T_c before and during gestation. Obesity was induced by cafeteria (CAF) feeding in female Wistar rats for 8 weeks prior to and during gestation, whereas control (CON) animals had free access to chow. Intraperitoneal temperature loggers measured daily T_c profiles throughout the study, while maternal body composition and leptin levels were assessed near term. Daily temperature profiles were examined for rhythmic features (mesor, amplitude and acrophase) by cosine regression analysis. CAF animals exhibited increased fat mass (93%) and associated hyperleptinemia (3.2-fold increase) compared to CON animals. CAF consumption reduced the average T_c (by up to 0.29°C) across the estrous cycle and most of pregnancy; however, T_c for CAF and CON animals converged toward the end of gestation. Obesity reduced the amplitude of T_c rhythms at estrus and proestrus and on day 8 of pregnancy, but increased the amplitude at day 20 of pregnancy. Photoperiod analysis revealed that obesity reduced T_c exclusively in the light period during pre-pregnancy but only during the dark period in late gestation. In conclusion, obesity alters rhythmic T_c profiles and reduces the magnitude of the T_c decline late in rat gestation, which may have implications for maternal health and fetal development.

Female offspring born to obese and insulin-resistant dams are not at increased risk for obesity and metabolic dysfunction during early development

The percentage of women who are obese at the time of conception or during pregnancy is increasing, with animal and human studies demonstrating that offspring born to obese dams or mothers are at increased risk for obesity and the metabolic syndrome. Our goal was to confirm in an experimental model of metabolic syndrome in the dam, whether the offspring would be at increased risk of obesity. Conversely, we observed that male offspring born to dams with metabolic syndrome had no alterations in their body mass profiles, whereas female offspring born to dams with metabolic syndrome were heavier at weaning, but exhibited no perturbations in energy metabolism. Moreover, they gained weight at a reduced rate versus female offspring born to healthy dams, and thus weighed less at study completion. Hence, our findings suggest that factors other than increased adiposity and insulin resistance during pregnancy are responsible for the increased risk of obesity in children born to obese mothers.

Somatic growth, aging, and longevity

Although larger species of animals typically live longer than smaller species, the relationship of body size to longevity within a species is generally opposite. The longevity advantage of smaller individuals can be considerable and is best documented in laboratory mice and in domestic dogs. Importantly, it appears to apply broadly, including humans. It is not known whether theses associations represent causal links between various developmental and physiological mechanisms affecting growth and/or aging. However, variations in growth hormone (GH) signaling are likely involved because GH is a key stimulator of somatic growth, and apparently also exerts various “pro-aging” effects. Mechanisms linking GH, somatic growth, adult body size, aging, and lifespan likely involve target of rapamycin (TOR), particularly one of its signaling complexes, mTORC1, as well as various adjustments in mitochondrial function, energy metabolism, thermogenesis, inflammation, and insulin signaling. Somatic growth, aging, and longevity are also influenced by a variety of hormonal and nutritional signals, and much work will be needed to answer the question of why smaller individuals may be likely to live longer.

Beyond gut feelings: how the gut microbiota regulates blood pressure

Hypertension is the leading risk factor for heart disease and stroke, and is estimated to cause 9.4 million deaths globally every year. The pathogenesis of hypertension is complex, but lifestyle factors such as diet are important contributors to the disease. High dietary intake of fruit and vegetables is associated with reduced blood pressure and lower cardiovascular mortality. A critical relationship between dietary intake and the composition of the gut microbiota has been described in the literature, and a growing body of evidence supports the role of the gut microbiota in the regulation of blood pressure. In this Review, we describe the mechanisms by which the gut microbiota and its metabolites, including short-chain fatty acids, trimethylamine N-oxide, and lipopolysaccharides, act on downstream cellular targets to prevent or contribute to the pathogenesis of hypertension. These effects have a direct influence on tissues such as the kidney, the endothelium, and the heart. Finally, we consider the role of the gut microbiota in resistant hypertension, the possible intergenerational effect of the gut microbiota on blood pressure regulation, and the promising therapeutic potential of gut microbiota modification to improve health and prevent disease.

Circulating exosomes in obstructive sleep apnea as phenotypic biomarkers and mechanistic messengers of end-organ morbidity

Obstructive sleep apnea (OSA), the most severe form of sleep disordered breathing, is characterized by intermittent hypoxia during sleep (IH), sleep fragmentation, and episodic hypercapnia. OSA is associated with increased risk for morbidity and mortality affecting cardiovascular, metabolic, and neurocognitive systems, and more recently with non-alcoholic fatty liver disease (NAFLD) and cancer-related deaths. Substantial variability in OSA outcomes suggests that genetically-determined and environmental and lifestyle factors affect the phenotypic susceptibility to OSA. Furthermore, OSA and obesity often co-exist and manifest activation of shared molecular end-organ injury mechanisms that if properly identified may represent potential therapeutic targets. A challenge in the development of non-invasive diagnostic assays in body fluids is the ability to identify clinically relevant biomarkers. Circulating extracellular vesicles (EVs) include a heterogeneous population of vesicular structures including exosomes, prostasomes, microvesicles (MVs), ectosomes and oncosomes, and are classified based on their size, shape and membrane surface composition. Of these, exosomes (30-100nm) are very small membrane vesicles derived from multi-vesicular bodies or from the plasma membrane and play important roles in mediating cell-cell communication via cargo that includes lipids, proteins, mRNAs, miRNAs and DNA. We have recently identified a unique cluster of exosomal miRNAs in both humans and rodents exposed to intermittent hypoxia as well as in patients with OSA with divergent morbid phenotypes. Here we summarize such recent findings, and will focus on exosomal miRNAs in both adult and children which mediate intercellular communication relevant to OSA and endothelial dysfunction, and their potential value as diagnostic and prognostic biomarkers.

Differential effects of early-life nutrient restriction in long-lived GHR-KO and normal mice

There is increasing evidence that growth hormone (GH) and insulin-like growth factor 1 (IGF-1) signaling (collectively referred to as somatotropic signaling) during development has a profound influence on aging and longevity. Moreover, the absence of GH action was shown to modify responses of adult mice to calorie restriction (CR) and other antiaging interventions. It was therefore of interest to determine whether GH resistance in GH receptor knockout (GHR-KO) mice would modify the effects of mild pre-weaning CR imposed by increasing the number of pups in a litter (the so-called litter crowding). In addition to the expected impact on body weight, litter crowding affected glucose homeostasis, hepatic expression of IGF-1 and genes related to lipid metabolism, and expression of inflammatory markers in white adipose tissue, with some of these effects persisting until the age of 2 years. Litter crowding failed to further extend the remarkable longevity of GHR-KO mice and, instead, reduced late life survival of GHR-KO females, an effect opposite to the changes detected in normal animals. We conclude that the absence of GH actions alters the responses to pre-weaning CR and prevents this intervention from extending longevity.

Late gestational intermittent hypoxia induces metabolic and epigenetic changes in male adult offspring mice

KEY POINTS

Late gestation during pregnancy has been associated with a relatively high prevalence of obstructive sleep apnoea (OSA). Intermittent hypoxia, a hallmark of OSA, could impose significant long-term effects on somatic growth, energy homeostasis and metabolic function in offspring. Here we show that late gestation intermittent hypoxia induces metabolic dysfunction as reflected by increased body weight and adiposity index in adult male offspring that is paralleled by epigenomic alterations and inflammation in visceral white adipose tissue. Fetal perturbations by OSA during pregnancy impose long-term detrimental effects manifesting as metabolic dysfunction in adult male offspring.

ABSTRACT

Pregnancy, particularly late gestation (LG), has been associated with a relatively high prevalence of obstructive sleep apnoea (OSA). Intermittent hypoxia (IH), a hallmark of OSA, could impose significant long-term effects on somatic growth, energy homeostasis, and metabolic function in offspring. We hypothesized that IH during late pregnancy (LG-IH) may increase the propensity for metabolic dysregulation and obesity in adult offspring via epigenetic modifications. Time-pregnant female C57BL/6 mice were exposed to LG-IH or room air (LG-RA) during days 13-18 of gestation. At 24 weeks, blood samples were collected from offspring mice for lipid profiles and insulin resistance, indirect calorimetry was performed and visceral white adipose tissues (VWAT) were assessed for inflammatory cells as well as for differentially methylated gene regions (DMRs) using a methylated DNA immunoprecipitation on chip (MeDIP-chip). Body weight, food intake, adiposity index, fasting insulin, triglycerides and cholesterol levels were all significantly higher in LG-IH male but not female offspring. LG-IH also altered metabolic expenditure and locomotor activities in male offspring, and increased number of pro-inflammatory macrophages emerged in VWAT along with 1520 DMRs (P < 0.0001), associated with 693 genes. Pathway analyses showed that genes affected by LG-IH were mainly associated with molecular processes related to metabolic regulation and inflammation. LG-IH induces metabolic dysfunction as reflected by increased body weight and adiposity index in adult male offspring that is paralleled by epigenomic alterations and inflammation in VWAT. Thus, perturbations to fetal environment by OSA during pregnancy can have long-term detrimental effects on the fetus, and lead to persistent metabolic dysfunction in adulthood.

Realizing the Potential of Adolescence to Prevent Transgenerational Conditioning of Noncommunicable Disease Risk: Multi-Sectoral Design Frameworks

Evidence from the field of Developmental Origins of Health and Disease (DOHaD) demonstrates that early life environmental exposures impact later-life risk of non-communicable diseases (NCDs). This has revealed the transgenerational nature of NCD risk, thus demonstrating that interventions to improve environmental exposures during early life offer important potential for primary prevention of DOHaD-related NCDs. Based on this evidence, the prospect of multi-sectoral approaches to enable primary NCD risk reduction has been highlighted in major international reports. It is agreed that pregnancy, lactation and early childhood offer significant intervention opportunities. However, the importance of interventions that establish positive behaviors impacting nutritional and non-nutritional environmental exposures in the pre-conceptual period in both males and females, thus capturing the full potential of DOHaD, must not be overlooked. Adolescence, a period where life-long health-related behaviors are established, is therefore an important life-stage for DOHaD-informed intervention. DOHaD evidence underpinning this potential is well documented. However, there is a gap in the literature with respect to combined application of theoretical evidence from science, education and public health to inform intervention design. This paper addresses this gap, presenting a review of evidence informing theoretical frameworks for adolescent DOHaD interventions that is accessible collectively to all relevant sectors.

From Genome-Wide Association Study to Phenome-Wide Association Study: New Paradigms in Obesity Research

Obesity is a condition in which excess body fat has accumulated over an extent that increases the risk of many chronic diseases. The current clinical classification of obesity is based on measurement of body mass index (BMI), waist-hip ratio, and body fat percentage. However, these measurements do not account for the wide individual variations in fat distribution, degree of fatness or health risks, and genetic variants identified in the genome-wide association studies (GWAS). In this review, we will address this important issue with the introduction of phenome, phenomics, and phenome-wide association study (PheWAS). We will discuss the new paradigm shift from GWAS to PheWAS in obesity research. In the era of precision medicine, phenomics and PheWAS provide the required approaches to better definition and classification of obesity according to the association of obese phenome with their unique molecular makeup, lifestyle, and environmental impact.

Maternal and newborn infants amino acid concentrations in obese women born themselves with normal and small for gestational age birth weight

This study was undertaken to compare amino acid concentrations in maternal and newborn infants' serum in normal pregnancy and two groups of obese women who were born themselves with normal and small for gestational age (SGA) birth weight. Maternal cholesterol, lipoproteins concentrations and maternal and infants amino acid concentrations were evaluated at the time of delivery in 28 normal pregnancies, 46 obese pregnant women with normal birth weight (Ob-AGA group) and 44 obese pregnant women born themselves SGA (Ob-SGA group). Mean birth weight of newborn infants in Ob-SGA group was significantly less than in normal and Ob-AGA groups. Cholesterol and lipoproteins were significantly elevated in obese women (more prominent in Ob-SGA group). Most amino acid concentrations and fetal-maternal amino acid gradients were significantly lower in Ob-SGA group. These data suggest significant changes in placental amino acid transport/synthetic function in obese women who were born themselves SGA.

Developmental programming by maternal obesity in 2015: Outcomes, mechanisms, and potential interventions

This article is part of a Special Issue "SBN 2014". Obesity in women of child-bearing age is a growing problem in developed and developing countries. Evidence from human studies indicates that maternal BMI correlates with offspring adiposity from an early age and predisposes to metabolic disease in later life. Thus the early life environment is an attractive target for intervention to improve public health. Animal models have been used to investigate the specific physiological outcomes and mechanisms of developmental programming that result from exposure to maternal obesity in utero. From this research, targeted intervention strategies can be designed. In this review we summarise recent progress in this field, with a focus on cardiometabolic disease and central control of appetite and behaviour. We highlight key factors that may mediate programming by maternal obesity, including leptin, insulin, and ghrelin. Finally, we explore potential lifestyle and pharmacological interventions in humans and the current state of evidence from animal models.

TallyHO obese female mice experience poor reproductive outcomes and abnormal blastocyst metabolism that is reversed by metformin

Obese women experience worse reproductive outcomes than normal weight women, specifically infertility, pregnancy loss, fetal malformations and developmental delay of offspring. The aim of the present study was to use a genetic mouse model of obesity to recapitulate the human reproductive phenotype and further examine potential mechanisms and therapies. New inbred, polygenic Type 2 diabetic TallyHO mice and age-matched control C57BL/6 mice were superovulated to obtain morula or blastocyst stage embryos that were cultured in human tubal fluid (HTF) medium. Deoxyglucose uptake was determined for individual insulin-stimulated blastocysts. Apoptosis was detected by confocal microscopy using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) assay and Topro-3 nuclear dye. Embryos were scored for TUNEL-positive as a percentage of total nuclei. AMP-activated protein kinase (AMPK) activation, tumour necrosis factor (TNF)-α expression and adiponectin expression were analysed by western immunoblot and confocal immunofluorescent microscopy. Lipid accumulation was assayed by BODIPY. Comparisons were made between TallyHO morulae cultured to blastocyst embryos in either HTF medium or HTF medium with 25 μg mL(-1) metformin. TallyHO mice developed whole body abnormal insulin tolerance, had decreased litter sizes and increased non-esterified fatty acid levels. Blastocysts from TallyHO mice exhibited increased apoptosis, decreased insulin sensitivity and decreased AMPK. A possible cause for the insulin resistance and abnormal AMPK phosphorylation was the increased TNF-α expression and lipid accumulation, as detected by BODIPY, in TallyHO blastocysts and decreased adiponectin. Culturing TallyHO morulae with the AMPK activator metformin led to a reversal of all the abnormal findings, including increased AMPK phosphorylation, improved insulin-stimulated glucose uptake and normalisation of lipid accumulation. Women with obesity and insulin resistance experience poor pregnancy outcomes. Previously we have shown in mouse models of insulin resistance that AMPK activity is decreased and that activators of AMPK reverse poor embryo outcomes. Here, we show for the first time using a genetically altered obese model, not a diet-induced model, that metformin reverses many of the adverse effects of obesity at the level of the blastocyst. Expanding on this we determine that activation of AMPK via metformin reduces lipid droplet accumulation, presumably by eliminating the inhibitory effects of TNF-α, resulting in normalisation of fatty acid oxidation and HADH2 (hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (trifunctional protein), alpha subunit) activity. Metformin exposure in vitro was able to partially reverse these effects, at the level of the blastocyst, and may thus be effective in preventing the adverse effects of obesity on pregnancy and reproductive outcomes.

Mechanisms and correlates of a healthy brain: a commentary

In this monograph, the message is that early inactivity and obesity lead to later chronic disease, and, as such, physical inactivity should be recognized as a public health crisis. Sedentary behavior, to some extent, serves a purpose in our current culture (e.g., keeping children indoors keeps them safe), and, as such, may not be amenable to change. Thus, it is important that we understand the underpinnings of later-developing chronic disease as this complex public health issue may have roots that go deeper than sedentary behavior. In this commentary, I speculate on the mechanisms for physical activity exacting positive changes on cognitive abilities. Three potential mechanisms are discussed: glucose transport, postnatal neurogenesis, and vitamin synthesis, all of which are inextricably linked to nutrition. This discussion of mechanisms is followed by a discussion of tractable correlates of the progression to non-communicable disease in the adult.

Developmental programming of hypothalamic neuronal circuits: impact on energy balance control

The prevalence of obesity in adults and children has increased globally at an alarming rate. Mounting evidence from both epidemiological studies and animal models indicates that adult obesity and associated metabolic disorders can be programmed by intrauterine and early postnatal environment- a phenomenon known as "fetal programming of adult disease." Data from nutritional intervention studies in animals including maternal under- and over-nutrition support the developmental origins of obesity and metabolic syndrome. The hypothalamic neuronal circuits located in the arcuate nucleus controlling appetite and energy expenditure are set early in life and are perturbed by maternal nutritional insults. In this review, we focus on the effects of maternal nutrition in programming permanent changes in these hypothalamic circuits, with experimental evidence from animal models of maternal under- and over-nutrition. We discuss the epigenetic modifications which regulate hypothalamic gene expression as potential molecular mechanisms linking maternal diet during pregnancy to the offspring's risk of obesity at a later age. Understanding these mechanisms in key metabolic genes may provide insights into the development of preventative intervention strategies.

Supplementation with methyl donors during lactation to high-fat-sucrose-fed dams protects offspring against liver fat accumulation when consuming an obesogenic diet

Methyl donor supplementation has been reported to prevent obesity-induced liver fat accumulation in adult rats. We hypothesized that this protection could be mediated by perinatal nutrition. For this purpose, we assessed the response to an obesogenic diet (high-fat-sucrose, HFS) during adulthood depending on maternal diet during lactation. Female Wistar rats fed control diet during pregnancy were assigned to four postpartum dietary groups: control, control supplemented with methyl donors (choline, betaine, folic acid, vitamin B12), HFS and HFS supplemented with methyl donors. At weaning, the male offspring was transferred to a chow diet and at week 12th assigned to a control or a HFS diet during 8 weeks. The offspring whose mothers were fed HFS during lactation showed increased adiposity (19%, P<0.001). When fed the HFS diet as adults, offspring whose mothers were HFS supplemented had more body fat (23%, P<0.001) than those from HFS non-supplemented. However, they showed lower liver fat accumulation (-18%, P<0.001). Srebf1, Dnmt1 and Lepr liver mRNA levels increased after adulthood HFS feeding. In those animals HFS fed during adulthood, previous maternal HFS decreased Lepr and Dnmt1 expression levels when compared with c-HFS offspring, while the supplementation of control and HFS-fed dams, respectively, induced higher hepatic Mme and Lepr mRNA levels after adult HFS intake compared with hfs-HFS offspring. In conclusion, maternal HFS diet during lactation influenced the response to an obesogenic diet in the adult progeny. Interestingly, dietary methyl donor supplementation in lactating mothers fed an obesogenic diet reduced liver fat accumulation, but increased adipose tissue storage in adult HFS-fed offspring.