Effects of maternal surgical weight loss in mothers on intergenerational transmission of obesity

The Impact of Traditional Food and Lifestyle Behavior on Epigenetic Burden of Chronic Disease

Noncommunicable chronic diseases (NCCDs) are the leading causes of morbidity and mortality globally. The mismatch between present day diets and ancestral genome is suggested to contribute to the NCCDs burden, which is promoted by traditional risk factors like unhealthy diets, physical inactivity, alcohol and tobacco. However, epigenetic evidence now suggests that cumulatively inherited epigenetic modifications may have made humans more prone to the effects of present day lifestyle factors. Perinatal starvation was widespread in the 19th century. This together with more recent events like increasing consumption of western and low fiber diets, smoking, harmful use of alcohol, physical inactivity, and environmental pollutants may have programed the human epigenome for higher NCCDs risk. In this review, on the basis of available epigenetic data it is hypothesized that transgenerational effects of lifestyle factors may be contributing to the current global burden of NCCDs. Thus, there is a need to reconsider prevention strategies so that the subsequent generations will not have to pay for our sins and those of our ancestors.

Strategies to increase the efficacy of using gut microbiota for the modulation of obesity

Obesity is one of the most serious global public health challenges of the 21st century. The adjustment of gut microbiota is often recommended as an efficient strategy to treat obesity. This modulation of gut microbiota can be performed by many methods, including dietary intervention, antibiotic application, the use of prebiotics and probiotics, bariatric surgery and faecal microbiota transplantation. In most cases, positive effects have been observed in response to treatment, but invalid and even contrary effects have also been observed in some cases due to factors that are unrelated to intervention methods, such as genetic factors, patient age or gender, environmental microbiota, climate, geography and lifestyle. These factors can cause variation of gut microbial populations and thus should also be taken into consideration when selecting modulation strategies.

Maternal weight prior and during pregnancy and offspring's BMI and adiposity at 5-6 years in the EDEN mother-child cohort

BACKGROUND

Beyond pre-pregnancy BMI, maternal weight change before and during pregnancy may also affect offspring adiposity.

OBJECTIVE

To investigate the relationship between maternal weight history before and during pregnancy with children's adiposity at 5-6 years.

METHODS

In 1069 mother-child dyads from the EDEN Cohort, we examined by linear regression the associations of children's BMI, fat mass and abdominal adiposity at 5-6 years with maternal pre-pregnancy BMI, pre-pregnancy average yearly weight change from age 20 and gestational weight gain. The shapes of relationships were investigated using splines and polynomial functions were tested.

RESULTS

Children's BMI and adiposity parameters were positively associated with maternal pre-pregnancy BMI, but these relationships were mainly seen in thin mothers, with no substantial variation for maternal BMI ranging from 22 to 35 kg/m² . Gestational weight gain was positively associated with children's BMI Z-score, but again more so in thin mothers. We found no association with pre-pregnancy weight change.

CONCLUSIONS

Before the adiposity rebound, maternal pre-pregnancy thinness explains most of the relationship with children's BMI. The relationship may emerge at older ages in children of overweight and obese mothers, and this latency may be an obstacle to early prevention.

Animal models of maternal high fat diet exposure and effects on metabolism in offspring: a meta-regression analysis

Animal models of maternal high fat diet (HFD) demonstrate perturbed offspring metabolism although the effects differ markedly between models. We assessed studies investigating metabolic parameters in the offspring of HFD fed mothers to identify factors explaining these inter-study differences. A total of 171 papers were identified, which provided data from 6047 offspring. Data were extracted regarding body weight, adiposity, glucose homeostasis and lipidaemia. Information regarding the macronutrient content of diet, species, time point of exposure and gestational weight gain were collected and utilized in meta-regression models to explore predictive factors. Publication bias was assessed using Egger's regression test. Maternal HFD exposure did not affect offspring birthweight but increased weaning weight, final bodyweight, adiposity, triglyceridaemia, cholesterolaemia and insulinaemia in both female and male offspring. Hyperglycaemia was found in female offspring only. Meta-regression analysis identified lactational HFD exposure as a key moderator. The fat content of the diet did not correlate with any outcomes. There was evidence of significant publication bias for all outcomes except birthweight. Maternal HFD exposure was associated with perturbed metabolism in offspring but between studies was not accounted for by dietary constituents, species, strain or maternal gestational weight gain. Specific weaknesses in experimental design predispose many of the results to bias.

Exercise rescues obese mothers' insulin sensitivity, placental hypoxia and male offspring insulin sensitivity

The prevalence of obesity during pregnancy continues to increase at alarming rates. This is concerning as in addition to immediate impacts on maternal wellbeing, obesity during pregnancy has detrimental effects on the long-term health of the offspring through non-genetic mechanisms. A major knowledge gap limiting our capacity to develop intervention strategies is the lack of understanding of the factors in the obese mother that mediate these epigenetic effects on the offspring. We used a mouse model of maternal-diet induced obesity to define predictive correlations between maternal factors and offspring insulin resistance. Maternal hyperinsulinemia (independent of maternal body weight and composition) strongly associated with offspring insulin resistance. To test causality, we implemented an exercise intervention that improved maternal insulin sensitivity without changing maternal body weight or composition. This maternal intervention prevented excess placental lipid deposition and hypoxia (independent of sex) and insulin resistance in male offspring. We conclude that hyperinsulinemia is a key programming factor and therefore an important interventional target during obese pregnancy, and propose moderate exercise as a promising strategy to improve metabolic outcome in both the obese mother and her offspring.

Using Genetic Variation to Explore the Causal Effect of Maternal Pregnancy Adiposity on Future Offspring Adiposity: A Mendelian Randomisation Study

BACKGROUND

It has been suggested that greater maternal adiposity during pregnancy affects lifelong risk of offspring fatness via intrauterine mechanisms. Our aim was to use Mendelian randomisation (MR) to investigate the causal effect of intrauterine exposure to greater maternal body mass index (BMI) on offspring BMI and fat mass from childhood to early adulthood.

METHODS AND FINDINGS

We used maternal genetic variants as instrumental variables (IVs) to test the causal effect of maternal BMI in pregnancy on offspring fatness (BMI and dual-energy X-ray absorptiometry [DXA] determined fat mass index [FMI]) in a MR approach. This was investigated, with repeat measurements, from ages 7 to 18 in the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 2,521 to 3,720 for different ages). We then sought to replicate findings with results for BMI at age 6 in Generation R (n = 2,337 for replication sample; n = 6,057 for total pooled sample). In confounder-adjusted multivariable regression in ALSPAC, a 1 standard deviation (SD, equivalent of 3.7 kg/m2) increase in maternal BMI was associated with a 0.25 SD (95% CI 0.21-0.29) increase in offspring BMI at age 7, with similar results at later ages and when FMI was used as the outcome. A weighted genetic risk score was generated from 32 genetic variants robustly associated with BMI (minimum F-statistic = 45 in ALSPAC). The MR results using this genetic risk score as an IV in ALSPAC were close to the null at all ages (e.g., 0.04 SD (95% CI -0.21-0.30) at age 7 and 0.03 SD (95% CI -0.26-0.32) at age 18 per SD increase in maternal BMI), which was similar when a 97 variant generic risk score was used in ALSPAC. When findings from age 7 in ALSPAC were meta-analysed with those from age 6 in Generation R, the pooled confounder-adjusted multivariable regression association was 0.22 SD (95% CI 0.19-0.25) per SD increase in maternal BMI and the pooled MR effect (pooling the 97 variant score results from ALSPAC with the 32 variant score results from Generation R) was 0.05 SD (95%CI -0.11-0.21) per SD increase in maternal BMI (p-value for difference between the two results = 0.05). A number of sensitivity analyses exploring violation of the MR results supported our main findings. However, power was limited for some of the sensitivity tests and further studies with relevant data on maternal, offspring, and paternal genotype are required to obtain more precise (and unbiased) causal estimates.

CONCLUSIONS

Our findings provide little evidence to support a strong causal intrauterine effect of incrementally greater maternal BMI resulting in greater offspring adiposity.

Influence of maternal obesity on the long-term health of offspring

In addition to immediate implications for pregnancy complications, increasing evidence implicates maternal obesity as a major determinant of offspring health during childhood and later adult life. Observational studies provide evidence for effects of maternal obesity on her offspring's risks of obesity, coronary heart disease, stroke, type 2 diabetes, and asthma. Maternal obesity could also lead to poorer cognitive performance and increased risk of neurodevelopmental disorders, including cerebral palsy. Preliminary evidence suggests potential implications for immune and infectious-disease-related outcomes. Insights from experimental studies support causal effects of maternal obesity on offspring outcomes, which are mediated at least partly through changes in epigenetic processes, such as alterations in DNA methylation, and perhaps through alterations in the gut microbiome. Although the offspring of obese women who lose weight before pregnancy have a reduced risk of obesity, few controlled intervention studies have been done in which maternal obesity is reversed and the consequences for offspring have been examined. Because the long-term effects of maternal obesity could have profound public health implications, there is an urgent need for studies on causality, underlying mechanisms, and effective interventions to reverse the epidemic of obesity in women of childbearing age and to mitigate consequences for offspring.

Pregnancy after bariatric surgery: improving outcomes for mother and child

The significant increase in the prevalence of obesity has led to an increase in the number of obese women who become pregnant. In this setting, in recent years, there has been an exponential rise in the number of bariatric procedures, with approximately half of them performed in women of childbearing age, and a remarkable surge in the number of women who become pregnant after having undergone bariatric surgery (BS). These procedures entail the risk of nutritional deficiencies, and nutrition is a crucial aspect during pregnancy. Therefore, knowledge and awareness of the consequences of these techniques on maternal and fetal outcomes is essential. Current evidence suggests a better overall obstetric outcome after BS, in comparison to morbid obese women managed conservatively, with a reduction in the prevalence of gestational diabetes mellitus, pregnancy-associated hypertensive disorders, macrosomia, and congenital defects. However, the risk of potential maternal nutritional deficiencies and newborns small for gestational age cannot be overlooked. Results concerning the incidence of preterm delivery and the number of C-sections are less consistent. In this paper, we review the updated evidence regarding the impact of BS on pregnancy.

Offspring predisposition to obesity due to maternal-diet-induced obesity in rats is preventable by dietary normalization before mating

SCOPE

We studied in rats whether the expected detrimental effects in offspring associated to maternal dietary obesity may be reverted by obesogenic diet removal 1 month before mating.

METHODS AND RESULTS

Female rats were fed a cafeteria diet (CD) from days 10 to 100 and then a standard diet (SD) (postcafeteria rats). One month after CD removal, postcafeteria rats and a group of SD-fed female rats (controls) were mated with males. At weaning, offspring were fed SD and followed until 4 months old. CD was effective at inducing obesity in dams. Its removal led to a reduction in body weight, although, after 30 days, rats retained excess body weight and fat than controls. During lactation, postcafeteria dams showed greater body fat, and higher leptin and adiponectin levels in milk than controls. From 2 months of life, offspring of postcafeteria dams displayed lower body weight than controls, with no differences in the percentage of fat, homeostatic model assessment for insulin resistance, or circulating parameters.

CONCLUSION

Removal of CD in obese rats before gestation, although without complete reversion of body weight excess, may prevent the expected detrimental effects in offspring associated to an excess fat accumulation in adulthood and the related metabolic disturbances.

Drosophila melanogaster: An emerging model of transgenerational effects of maternal obesity

The prevalence of obesity in the world is endemic with one rapidly growing health concern being maternal obesity. Obesity during pregnancy increases the risk of gestational diabetes, miscarriage, and preeclampsia, while rendering offspring susceptible to developmental anomalies and long-term metabolic complications including type 2 diabetes and cardiovascular disease. Several studies in humans and rodents demonstrate a correlation between the risks of maternal overnutrition and factors such as epigenetics, mitochondrial dysfunction, insulin resistance, ER stress, and immune system disruption. At present, the molecular mechanisms connecting these factors to maternal obesity are unknown. This review focuses on the use of Drosophila melanogaster to study human metabolic diseases, including obesity, and its emerging use to elucidate the mechanisms of maternal overnutrition and the impact on offspring.

Maternal obesity and prenatal programming

Obesity is a significant and increasing public health concern in the United States and worldwide. Clinical and epidemiological evidence clearly shows that genetic and environmental factors contribute to the increased susceptibility of humans to obesity and its associated comorbidities; the interplay of these factors is explained by the concept of epigenetics. The impact of maternal obesity goes beyond the newborn period; fetal programming during the critical window of pregnancy, can have long term detrimental effects on the offspring as well as future generations. Emerging evidence is uncovering a link between the clinical and molecular findings in the offspring with epigenetic changes in the setting of maternal obesity. Research targeted towards reducing the transgenerational propagation and developmental programming of obesity is vital in reducing the increasing rates of disease.

Maternal Obesity in Pregnancy Developmentally Programs Adipose Tissue Inflammation in Young, Lean Male Mice Offspring

Obesity during pregnancy has a long-term effect on the health of the offspring including risk of developing the metabolic syndrome. Using a mouse model of maternal diet-induced obesity, we employed a genome-wide approach to investigate the microRNA (miRNA) and miRNA transcription profile in adipose tissue to understand mechanisms through which this occurs. Male offspring of diet-induced obese mothers, fed a control diet from weaning, showed no differences in body weight or adiposity at 8 weeks of age. However, offspring from the obese dams had up-regulated cytokine (Tnfα; P < .05) and chemokine (Ccl2 and Ccl7; P < .05) signaling in their adipose tissue. This was accompanied by reduced expression of miR-706, which we showed can directly regulate translation of the inflammatory proteins IL-33 (41% up-regulated; P < .05) and calcium/calmodulin-dependent protein kinase 1D (30% up-regulated; P < .01). We conclude that exposure to obesity during development primes an inflammatory environment in adipose tissue that is independent of offspring adiposity. Programming of adipose tissue miRNAs that regulate expression of inflammatory signaling molecules may be a contributing mechanism.

Early nutrition, epigenetics, and cardiovascular disease

PURPOSE OF REVIEW

Here, we provide a summary of the current knowledge on the impact of early life nutrition on cardiovascular diseases that have emerged from studies in humans and experimental animal models. The involvement of epigenetic mechanisms in the Developmental Origins of Health and Disease will be discussed in relation to the implications for the heart and the cardiovascular system.

RECENT FINDINGS

Environmental cues, such as parental diet and a suboptimal in utero environment can shape growth and development, causing long-lasting cardiometabolic perturbations. Increasing evidence suggest that these effects are mediated at the epigenomic level, and can be passed onto future generations. In the last decade, epigenetic mechanisms (DNA methylation, histone modifications) and RNA-based mechanisms (microRNAs, piRNAs, and tRNAs) have therefore emerged as potential candidates for mediating inheritance of cardiometabolic diseases.

SUMMARY

The burden of obesity and associated cardiometabolic diseases is believed to arise through interaction between an individual's genetics and the environment. Moreover, the risk of developing poor cardiometabolic health in adulthood is defined by early life exposure to pathological cues and can be inherited by future generations, initiating a vicious cycle of transmission of disease. Elucidating the molecular triggers of such a process will help tackle and prevent the uncontrolled rise in obesity and cardiometabolic disease.

Impact of inter-pregnancy BMI change on perinatal outcomes: a retrospective cohort study

OBJECTIVE

To examine the patterns and predictors of inter-pregnancy body mass index (BMI) change and its impact on perinatal outcomes in the second pregnancy.

DESIGN

Retrospective cohort study.

SETTING

Tertiary teaching hospital in Adelaide, Australia.

POPULATION

Women with their first and second consecutive, singleton deliveries occurring between 2000 and 2012 (N=5371).

METHODS

Inter-pregnancy weight change calculated based on difference between BMI at respective antenatal booking visits. Association between inter-pregnancy weight change and perinatal outcomes investigated using multivariate generalised linear models, with stratification according to initial maternal BMI category in first pregnancy.

MAIN OUTCOME MEASURES

Gestational diabetes (GDM); pregnancy induced hypertensive disorders; small-for-gestational age (SGA); preterm birth; large-for-gestational age (LGA) and macrosomia (>4500g).

RESULTS

On average, women with a normal BMI gained 1kg/m(2) between first and second pregnancies, while women who were overweight or obese gained 1.37kg/m(2). Among women with a normal BMI in their first pregnancy, a BMI increase of ≥4kg/m(2) was associated with increased risk of developing GDM (aRR 1.97; 95% CI 1.22-3.19), a macrosomic (aRR 4.06; 95% CI 2.25-7.34) or LGA infant (aRR 1.31 0.96-1.78) in the second pregnancy, while a reduction in BMI (≤-2kg/m(2)) was associated with an increased risk of SGA (aRR 1.94; 1.19-3.16). Among women who were overweight or obese in their first pregnancy, a BMI increase of ≥2-4 and ≥4kg/m(2) was associated with increased risks of developing GDM in the second pregnancy (aRR 1.39; 95% CI 1.01-1.91 and aRR 1.64 95% CI 1.16-2.31; ptrend<0.001), while no associations were observed for a BMI increase and risk of a macrosomic, SGA, or LGA infant. In contrast, reduction in BMI (≤-2kg/m(2)) was associated with a reduced risk of GDM (aRR 0.58 95% CI 0.37-0.90) and SGA (aRR 0.47; 95% CI 0.25-0.87).

CONCLUSION

Increases in BMI between pregnancies is associated with an increased risk for perinatal complications, even in normal-weight women, while a reduction in BMI is associated with improved perinatal outcomes among women who are overweight/obese. Inter-pregnancy weight control is an important target to reduce the risk of an adverse perinatal outcome in a subsequent pregnancy.

Pregnancy and perinatal outcomes according to surgery to conception interval and gestational weight gain in women with previous gastric bypass

OBJECTIVE

To compare perinatal and pregnancy outcomes including adherence to the Institute of Medicine's (IOM) recommendations for gestational weight gain (GWG) in pregnant women with conception <18 months (early group) compared to ≥18 months following gastric bypass (late group).

METHODS

Retrospective cohort study comprising 71 women with gastric bypass and a singleton pregnancy presenting at Odense University Hospital, November 2007-October 2013. Data were extracted from medical records and laboratory systems. The primary outcomes were timing of pregnancy and adherence to the IOM's recommendations for GWG. Secondary outcomes were birthweight, preterm delivery, cesarean section (CS), iron deficiency and post partum hemorrhage (PPH).

RESULTS

Forty-three (61%) women conceived less than 18 months after gastric bypass surgery. Women in the late group had a significantly higher risk of requiring CS or receiving intravenous iron supplementation compared to the early group (57% versus 30%, p = 0.03 and 29% versus 7%, p = 0.02, respectively). Early conception was not significantly associated with insufficient GWG, preterm delivery or birthweight. Among 54 women with information on GWG, only 13 (24%) had an appropriate GWG.

CONCLUSION

The majority of pregnant women with gastric bypass did not fulfill guidelines for GWG; however, this study could not support the recommendation to postpone pregnancy.

Association of maternal diabetes/glycosuria and pre-pregnancy body mass index with offspring indicators of non-alcoholic fatty liver disease

BACKGROUND

Little is known about early life determinants of non-alcoholic fatty liver disease (NAFLD). We examined associations of maternal pregnancy diabetes/glycosuria and pre-pregnancy body mass index (BMI) with offspring markers of NAFLD and liver pathology and examined mediation by birthweight and concurrent offspring adiposity.

METHODS

We used data from a UK prospective pregnancy cohort. Offspring underwent abdominal ultrasonography (USS) at mean age 17.8 years. Outcomes included USS-assessed fatty liver, estimated liver volume and shear velocity, a variant of elastography (a marker of liver fibrosis) (N = 1 215) and blood-based markers of liver pathology [alanine amino transferase, aspartate amino transferase, gamma- glutamyltransferase and haptoglobin] (N = 2 359).

RESULTS

2.1 % (N = 25) of participants had USS-assessed fatty liver [maternal diabetes/glycosuria (N = 7) and no diabetes/glycosuria (N = 18)]. Maternal diabetes/glycosuria was associated with greater odds of offspring USS fatty liver in confounder adjusted models [adjusted odds ratio (aOR) 6.74 (95 % confidence interval (CI) 2.47, 18.40)] and higher shear velocity [adjusted ratio of geometric mean (aRGM):1.10 (95 % CI 1.05, 1.15)]. These associations were not mediated by offspring birthweight or concurrent adiposity. Maternal diabetes/glycosuria was not associated with liver volume or blood-based outcomes. Greater maternal pre-pregnancy BMI was associated with greater odds of offspring USS fatty liver [aOR 2.72 (95 % CI: 1.20, 6.15)], higher liver volume [aRGM 1.03 (95 % CI 1.00, 1.07)] and shear velocity [aRGM1.03 (95 % CI: 1.01, 1.06)] in confounder adjusted models. These associations were largely mediated by offspring adiposity. Maternal pre-pregnancy BMI was not consistently associated with blood-based outcomes.

CONCLUSIONS

Results suggest that maternal pregnancy diabetes/glycosuria is associated with offspring NAFLD through mechanisms other than offspring's own adiposity.

Parental pre-pregnancy BMI is a dominant early-life risk factor influencing BMI of offspring in adulthood

Objective

We examined parental and early‐life variables in order to identify risk factors for adulthood overweight and obesity in offspring. We report here on the longitudinal prevalence of overweight and obesity in Australian children born between 1989 and 1991 and followed from birth to age 22.

Methods

Data were analysed on 1355 participants from the Western Australian Pregnancy Cohort (Raine) Study, with anthropometry collected during pregnancy, at birth, one year and at three yearly intervals thereafter. Multivariate analyses and cross‐sectional logistic regression quantified the timing and contribution of early‐life risk factors for overweight and obesity in young‐adulthood.

Results

At five years of age 12.6% of children were overweight and 5.2% were obese. By early adulthood, the prevalence of obesity had increased to 12.8%, whilst overweight remained relatively stable at 14.2% (range from early childhood to adulthood 11–16%). Parental pre‐pregnancy body mass index (BMI) was the strongest determinant of adult offspring BMI. Although rapid first year weight gain was associated with increased offspring BMI, the impact of first year weight‐gain diminished over childhood, whilst the impact of parental BMI increased over time.

Conclusions

Parental pre‐pregnancy BMI and rapid early‐life weight gain predispose offspring to obesity in adulthood.

The early origins of obesity and insulin resistance: timing, programming and mechanisms

Maternal obesity is associated with an increased risk of developing gestational diabetes mellitus and it also results in an increased risk of giving birth to a large baby with increased fat mass. Furthermore, it is also contributes to an increased risk of obesity and insulin resistance in the offspring in childhood, adolescence and adult life. It has been proposed that exposure to maternal obesity may therefore result in an 'intergenerational cycle' of obesity and insulin resistance. There is significant interest in whether exposure to maternal obesity around the time of conception alone contributes directly to poor metabolic outcomes in the offspring and whether dieting in the obese mother before pregnancy or around the time of conception has metabolic benefits for the offspring. This review focusses on experimental and clinical studies that have investigated the specific impact of exposure to maternal obesity during the periconceptional period alone or extending beyond conception on adipogenesis, lipogenesis and on insulin signalling pathways in the fat, liver and muscle of the offspring. Findings from these studies highlight the need for a better evidence base for the development of dietary interventions in obese women before pregnancy and around the time of conception to maximize the metabolic benefits and minimize the metabolic costs for the next generation.

Hematological, Biochemical, and Immunological Laboratory and Histomorphological Effects of Sleeve Gastrectomy on Female Rats

Restriction of food intake leads to immunologic and histomorphological changes in rats demonstrated by Moriyama. This study is planned to show how sleeve gastrectomy restricts food intake and its effects on biochemical liver function, immunologic and hematologic laboratory parameters, and histomorphological changes in rats. We used sleeve gastrectomy model on seven young adult female rats and compared study group with sham and control groups. Food consumption of rats was measured. All rats were sacrificed on the 50th day, and blood and tissue samples were collected. There was a significant low food intake in sleeve gastrectomy group (p = 0.013). No differences were observed on hematologic, biochemical, and immunologic laboratory parameters between groups. Toxicity parameters in liver samples such as cytoplasmic atrophy, single-cell hepatocellular necrosis, and necrotic eosinophilic cells were significantly high in sleeve gastrectomy group (p = 0.005). Histomorphological examination of the spleen and kidneys revealed significant changes in sleeve gastrectomy and sham groups compared with controls (p = 0.004 and p = 0.018, respectively). Although sleeve gastrectomy does not lead to alteration in hematologic, biochemical, and immunologic laboratory parameters, it causes decreased food consumption, which results in toxicological histomorphological changes in rat liver as well as some changes in kidney and spleen samples.

A short-term transition from a high-fat diet to a normal-fat diet before pregnancy exacerbates female mouse offspring obesity

BACKGROUND/OBJECTIVES

Recent findings have highlighted the detrimental influence of maternal overnutrition and obesity on fetal development and early life development. However, there are no evidence-based guidelines regarding the optimal strategy for dietary intervention before pregnancy.

SUBJECTS/METHODS

We used a murine model to study whether switching from a high-fat (HF) diet to a normal-fat (NF) diet (H1N group) 1 week before pregnancy could lead to in utero reprogramming of female offspring obesity; comparator groups were offspring given a consistent maternal HF group or NF group until weaning. After weaning, all female offspring were given the HF diet for either 9 or 12 weeks before being killed humanely.

RESULTS

H1N treatment did not result in maternal weight loss before pregnancy. NF offsprings were neither obese nor glucose intolerant during the entire experimental period. H1N offsprings were most obese after the 12-week postweaning HF diet and displayed glucose intolerance earlier than HF offsprings. Our mechanistic study showed reduced adipocyte insulin receptor substrate 1 (IRS1) and hepatic IRS2 expression and increased adipocyte p-Ser(636/639) and p-Ser(612) of H1N or HF offspring compared with that in the NF offspring. Among all groups, the H1N offspring had lowest level of IRS1 and the highest levels of p-Ser(636/639) and p-Ser(612) in gonadal adipocyte. In addition, the H1N offspring further reduced the expression of Glut4 and Glut2, vs those of the HF offspring, which was lower compared with the NF offspring. There were also enhanced expression of genes inhibiting glycogenesis and decreased hepatic glycogen in H1N vs HF or NF offspring. Furthermore, we showed extremely higher expression of lipogenesis and adipogenesis genes in gonadal adipocytes of H1N offspring compared with all other groups.

CONCLUSIONS

Our results suggest that a transition from an HF diet to an NF diet shortly before pregnancy, without resulting in maternal weight loss, is not necessarily beneficial and may have deleterious effects on offspring.

MECHANISMS IN ENDOCRINOLOGY: Metabolic syndrome through the female life cycle

The normal function of the female reproductive system is closely linked to energy homeostasis with the ultimate scope of fertility and human race perpetuation through the centuries. During a woman's lifetime there are normal events such as puberty, pregnancy and menopause which are related to alterations in energy homeostasis and gonadal steroids levels followed by increase of body fat and insulin resistance, important components of metabolic syndrome (MetS). Pathological conditions such as premature adrenarche, polycystic ovary syndrome and gestational diabetes also present with shifts in gonadal steroid levels and reduced insulin sensitivity. The aim of this review is to discuss these conditions, both normal and pathological, analyzing the changes or abnormalities in ovarian function that coexist with metabolic abnormalities which resemble MetS in relationship with environmental, genetic and epigenetic factors.

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.

Maternal and perinatal outcomes after bariatric surgery: a Spanish multicenter study

BACKGROUND

Bariatric surgery (BS) has become more frequent among women of child-bearing age. Data regarding the underlying maternal and perinatal risks are scarce. The objective of this nationwide study is to evaluate maternal and perinatal outcomes after BS.

METHODS

We performed a retrospective observational study of 168 pregnancies in 112 women who underwent BS in 10 tertiary hospitals in Spain over a 15-year period. Maternal and perinatal outcomes, including gestational diabetes mellitus (GDM), pregnancy-associated hypertensive disorders (PAHD), pre-term birth cesarean deliveries, small and large for gestational age births (SGA, LGA), still births, and neonatal deaths, were evaluated. Results were further compared according to the type of BS performed: restrictive techniques (vertical-banded gastroplasty, sleeve gastrectomy, and gastric banding), Roux-en-Y gastric bypass (RYGB), and biliopancreatic diversion (BPD).

RESULTS

GDM occurred in five (3 %) pregnancies and there were no cases of PAHD. Women whose pregnancies occurred before 1 year after BS had a higher pre-gestational body mass index (BMI) than those who got pregnant 1 year after BS (34.6 ± 7.7 vs 30.4 ± 5.3 kg/m(2), p = 0.007). In pregnancies occurring during the first year after BS, a higher rate of stillbirths was observed compared to pregnancies occurring after this period of time (35.5 vs 16.8 %, p = 0.03). Women who underwent BPD delivered a higher rate of SGA babies than women with RYGB or restrictive procedures (34.8, 12.7, and 8.3 %, respectively).

CONCLUSIONS

Pregnancy should be scheduled at least 1 year after BS. Malabsorptive procedures are associated to a higher rate of SGA births.

Intergenerational transmission of macrosomia in women with gestational diabetes and normal glucose tolerance

OBJECTIVES

It has been suggested that neonatal macrosomia may contribute to increased risk of obesity and type 2 diabetes in later life. Much less is known about the association between maternal birth weight (MBW) and offspring birth weight (OBW). This retrospective study evaluated the prevalence of macrosomia in women with treated gestational diabetes mellitus (GDM) and normal glucose tolerance during pregnancy. The study also investigated associations between MBW and OBW.

STUDY DESIGN

Medical records of 519 pregnant women with treated GDM and 766 women with normal glucose tolerance, referred to the Gestational Diabetes Outpatient Clinic in Szczecin, Poland, were analyzed. The following data were assessed: maternal age, pregravid body weight, height, gestational weight gain, prior GDM, prior macrosomia, MBW and OBW. Birth weight was classified as small for gestational age (SGA), appropriate for gestational age (AGA), large for gestational age (LGA) and macrosomia (≥4000g). OBW was obtained from birth certificates, and MBW was obtained from birth certificates or self-report.

RESULTS

The overall prevalence of macrosomia was 8.1%, and was comparable in subgroups of women with and without GDM (7.7% and 8.4%, respectively; p=0.905). The frequencies of SGA, AGA and LGA did not differ between study groups. A positive correlation was found between MBW and OBW in women with treated GDM (r=0.211, p<0.001) and in women with normal glucose tolerance (r=0.220, p<0.001). Regardless of glucose tolerance status during pregnancy, the greatest proportion of macrosomic babies were born to mothers who were themselves born macrosomic (26.5% in mothers with GDM and 20.0% in mothers with normal glucose tolerance; p=0.631). On logistic regression, MBW was found to be a robust predictor of macrosomia in offspring [odds ratio (OR) 1.64, 95% confidence interval (CI) 1.15-2.36 in women with treated GDM; OR 1.35, 95% CI 1.07-1.76 in women with normal glucose tolerance). Other independent predictors of fetal macrosomia were gestational weight gain, prior macrosomia and pregravid body mass index (BMI).

CONCLUSIONS

MBW, prior macrosomia, pregravid BMI and gestational weight gain were predictors of macrosomia in offspring, but GDM was not. High MBW seems to contribute to intergenerational transmission of macrosomia.

Early life origins of metabolic disease: Developmental programming of hypothalamic pathways controlling energy homeostasis

A wealth of animal and human studies demonstrate that perinatal exposure to adverse metabolic conditions - be it maternal obesity, diabetes or under-nutrition - results in predisposition of offspring to develop obesity later in life. This mechanism is a contributing factor to the exponential rise in obesity rates. Increased weight gain in offspring exposed to maternal obesity is usually associated with hyperphagia, implicating altered central regulation of energy homeostasis as an underlying cause. Perinatal development of the hypothalamus (a brain region key to metabolic regulation) is plastic and sensitive to metabolic signals during this critical time window. Recent research in non-human primate and rodent models has demonstrated that exposure to adverse maternal environments impairs the development of hypothalamic structure and consequently function, potentially underpinning metabolic phenotypes in later life. This review summarizes our current knowledge of how adverse perinatal environments program hypothalamic development and explores the mechanisms that could mediate these effects.

Maternal obesity during pregnancy and cardiovascular development and disease in the offspring

Maternal obesity during pregnancy is an important public health problem in Western countries. Currently, obesity prevalence rates in pregnant women are estimated to be as high as 30 %. In addition, approximately 40 % of women gain an excessive amount of weight during pregnancy in Western countries. An accumulating body of evidence suggests a long-term impact of maternal obesity and excessive weight gain during pregnancy on adiposity, cardiovascular and metabolic related health outcomes in the offspring in fetal life, childhood and adulthood. In this review, we discuss results from recent studies, potential underlying mechanisms and challenges for future epidemiological studies.

Effects of Maternal Obesity on Fetal Programming: Molecular Approaches

Maternal obesity has become a worldwide epidemic. Obesity and a high-fat diet have been shown to have deleterious effects on fetal programming, predisposing offspring to adverse cardiometabolic and neurodevelopmental outcomes. Although large epidemiological studies have shown an association between maternal obesity and adverse outcomes for offspring, the underlying mechanisms remain unclear. Molecular approaches have played a key role in elucidating the mechanistic underpinnings of fetal malprogramming in the setting of maternal obesity. These approaches include, among others, characterization of epigenetic modifications, microRNA expression, the gut microbiome, the transcriptome, and evaluation of specific mRNA expression via quantitative reverse transcription polmerase chain reaction (RT-qPCR) in fetuses and offspring of obese females. This work will review the data from animal models and human fluids/cells regarding the effects of maternal obesity on fetal and offspring neurodevelopment and cardiometabolic outcomes, with a particular focus on molecular approaches.

Mother's pre-pregnancy BMI is an important determinant of adverse cardiometabolic risk in childhood

OBJECTIVE

Maternal adiposity is associated with poor offspring cardiometabolic health. We aimed to evaluate the relationship of maternal pre-pregnancy body mass index (BMI) on the BMI, body composition and cardiometabolic characteristics of the offspring.

METHODS

Forty offspring of overweight/obese mothers (O-OW) and 28 offspring of normal weight mothers (O-NW) underwent evaluation of body composition, abdominal fat distribution, blood pressure measurement, fasting lipids and an oral glucose tolerance test. The anthropometric and cardiometabolic characteristics of O-OW were compared with those of O-NW, and the relationship to maternal BMI was evaluated.

RESULTS

Subjects (mean age: 12.6 ± 0.4, female: 52.9%) had similar gestational age, birth weight, age, gender, and Tanner stage. However, O-OW had a significantly higher BMI (24.4 ± 1.2 vs. 19.7 ± 0.8 kg/m(2) , p = 0.001), % body fat (31.7 ± 1.6 vs. 24.6 ± 1.1%, p < 0.001), visceral fat (41.9 ± 4.7 vs. 26.1 ± 3.9 cm(2) , p = 0.012) with no difference in lean body mass compared with O-NW. O-OW had lower whole body insulin sensitivity index (WBISI) with an adverse cardiovascular disease risk profile [higher blood pressure (BP), triglycerides to high-density lipoprotein (HDL) ratio, hs-C-reactive protein (CRP) and lower HDL]. In addition to offspring's %body fat (β = -0.60, p < 0.001), maternal pre-pregnancy BMI (β = -0.19, p = 0.046) contributed significantly and independently to the offspring's WBISI (R(2) =0.55, p < 0.001).

CONCLUSIONS

High pre-pregnancy BMI is an important contributor to excess adiposity, insulin resistance, and cardiometabolic disease risk in the offspring during childhood.

Maternal pre-pregnancy BMI and gestational weight gain, offspring DNA methylation and later offspring adiposity: findings from the Avon Longitudinal Study of Parents and Children

Background: Evidence suggests that in utero exposure to undernutrition and overnutrition might affect adiposity in later life. Epigenetic modification is suggested as a plausible mediating mechanism.

Methods: We used multivariable linear regression and a negative control design to examine offspring epigenome-wide DNA methylation in relation to maternal and offspring adiposity in 1018 participants.

Results: Compared with neonatal offspring of normal weight mothers, 28 and 1621 CpG sites were differentially methylated in offspring of obese and underweight mothers, respectively [false discovert rate (FDR)-corrected P-value < 0.05), with no overlap in the sites that maternal obesity and underweight relate to. A positive association, where higher methylation is associated with a body mass index (BMI) outside the normal range, was seen at 78.6% of the sites associated with obesity and 87.9% of the sites associated with underweight. Associations of maternal obesity with offspring methylation were stronger than associations of paternal obesity, supporting an intrauterine mechanism. There were no consistent associations of gestational weight gain with offspring DNA methylation. In general, sites that were hypermethylated in association with maternal obesity or hypomethylated in association with maternal underweight tended to be positively associated with offspring adiposity, and sites hypomethylated in association with maternal obesity or hypermethylated in association with maternal underweight tended to be inversely associated with offspring adiposity.

Conclusions: Our data suggest that both maternal obesity and, to a larger degree, underweight affect the neonatal epigenome via an intrauterine mechanism, but weight gain during pregnancy has little effect. We found some evidence that associations of maternal underweight with lower offspring adiposity and maternal obesity with greater offspring adiposity may be mediated via increased DNA methylation.

Exercise in pregnancies complicated by obesity: achieving benefits and overcoming barriers

An increasing number of women are entering pregnancy in an overweight or obese state. Obese women and their offspring are at increased risk of adverse perinatal outcomes, which may be improved by regular moderate-intensity antenatal exercise. Current guidelines recommend that all pregnant women without contraindications engage in ≥30 minutes of moderate-intensity exercise on a daily basis. However, obese women are usually less physically active and tend to further reduce activity levels during pregnancy. This commentary summarizes the potential short- and long-term benefits of antenatal exercise in obese pregnant women, highlights the challenges they face, and discusses means of improving their exercise levels. In addition, we make recommendations on exercise prescription for pregnancies complicated by obesity.

Maternal and neonatal outcomes for pregnancies before and after gastric bypass surgery

BACKGROUND

Interaction between maternal obesity, intrauterine environment and adverse clinical outcomes of newborns has been described.

METHODS

Using statewide birth certificate data, this retrospective, matched-control cohort study compared paired birth weights and complications of infants born to women before and after Roux-en-Y gastric bypass surgery (RYGB) and to matched obese non-operated women in several different groups. Women who had given birth to a child before and after RYGB (group 1; n=295 matches) and women with pregnancies after RYGB (group 2; n=764 matches) were matched to non-operated women based on age, body mass index (BMI) prior to both pregnancy and RYGB, mother's race, year of mother/s birth, date of infant births and birth order. In addition, birth weights of 13 143 live births before and/or after RYGB of their mothers (n=5819) were compared (group 3).

RESULTS

Odds ratios (ORs) for having a large-for-gestational-age (LGA) neonate were significantly less after RYGB than for non-surgical mothers: ORs for groups 1 and 2 were 0.19 (0.08-0.38) and 0.33 (0.21-0.51), respectively. In contrast, ORs in all three groups for risk of having a small for gestational age (SGA) neonate were greater for RYGB mothers compared to non-surgical mothers (ORs were 2.16 (1.00-5.04); 2.16 (1.43-3.32); and 2.25 (1.89-2.69), respectively). Neonatal complications were not different for group 1 RYGB and non-surgical women for the first pregnancy following RYGB. Pregnancy-induced hypertension and gestational diabetes were significantly lower for the first pregnancy of mothers following RYGB compared to matched pregnancies of non-surgical mothers.

CONCLUSION

Women who had undergone RYGB not only had lower risk for having an LGA neonate compared to BMI-matched mothers, but also had significantly higher risk for delivering an SGA neonate following RYGB. RYGB women were less likely than non-operated women to have pregnancy-related hypertension and diabetes.

Influences of gestational obesity on associations between genotypes and gene expression levels in offspring following maternal gastrointestinal bypass surgery for obesity

METHODS

Whole-genome genotyping and gene expression analyses in blood of 22 BMS and 23 AMS offspring from 19 mothers were conducted using Illumina HumanOmni-5-Quad and HumanHT-12 v4 Expression BeadChips, respectively. Using PLINK we analyzed interactions between offspring gene variations and maternal surgical status on offspring gene expression levels. Altered biological functions and pathways were identified and visualized using DAVID and Ingenuity Pathway Analysis.

RESULTS

Significant interactions (p ≤ 1.22 x 10(-12)) were found for 525 among the 16,060 expressed transcripts: 1.9% of tested SNPs were involved. Gene function and pathway analysis demonstrated enrichment of transcription and of cellular metabolism functions and overrepresentation of cellular stress and signaling, immune response, inflammation, growth, proliferation and development pathways.

CONCLUSION

We suggest that impaired maternal gestational metabolic fitness interacts with offspring gene variations modulating gene expression levels, providing potential mechanisms explaining improved cardiometabolic risk profiles of AMS offspring related to ameliorated maternal lipid and carbohydrate metabolism.

Mitigating or exacerbating effects of maternal-fetal programming of female mice through the food choice environment

Humans live, eat, and become overweight/obese in complex surroundings where there are many available food choices. Prenatal exposure to poor food choices predisposes offspring to increased negative health risks, including obesity. Many animal experiments have analyzed intergenerational body weight parameters in an environment without food choices, which may not be directly translatable to the human food environment. In this study, offspring from mothers with a defined high-fat diet (HFD) or low-fat diet (LFD) were arbitrarily assigned to either an exclusively LFD or HFD or to a diet where they have a choice between LFD and HFD (choice diet). Offspring displayed negative outcomes of increased body weight, body fat, serum leptin, and blood glucose levels when given the choice diet compared with offspring on the LFD. Conversely, improved energy expenditure was found for offspring given the choice diet compared with offspring from HFD dams given LFD. In addition, maternal diet-specific influences on offspring metabolic parameters were identified, especially in offspring from HFD dams, including positive outcomes of reduced leptin in LFD offspring, reduced corticosterone and cholesterol levels in HFD offspring, and increased exercise levels in choice offspring, as well as the negative outcome of increased calorie intake in LFD offspring from HFD dams. This defined model can now be used as the basis for future studies to characterize the cycle of inter- and intragenerational obesity and whether more realistic diet environments, especially those including choice, can mitigate phenotype.

Gene-environment interactions controlling energy and glucose homeostasis and the developmental origins of obesity

Obesity and type 2 diabetes mellitus (T2DM) often occur together and affect a growing number of individuals in both the developed and developing worlds. Both are associated with a number of other serious illnesses that lead to increased rates of mortality. There is likely a polygenic mode of inheritance underlying both disorders, but it has become increasingly clear that the pre- and postnatal environments play critical roles in pushing predisposed individuals over the edge into a disease state. This review focuses on the many genetic and environmental variables that interact to cause predisposed individuals to become obese and diabetic. The brain and its interactions with the external and internal environment are a major focus given the prominent role these interactions play in the regulation of energy and glucose homeostasis in health and disease.

Programming of cardiovascular disease across the life-course

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

Adipose tissue dysregulation and metabolic consequences in childhood and adolescent obesity: potential impact of dietary fat quality

Evidence suggests that at a population level, childhood and adolescent obesity increase the long-term risk of chronic diseases such as type 2 diabetes and CVD. At an individual level, however, the metabolic consequences of obesity in youth vary immensely. Despite comparable BMI, some adolescents develop impaired glucose tolerance while others maintain normal glucose homeostasis. It has been proposed that the variation in the capacity to store lipid in the subcutaneous adipose tissue (SAT) may partially discriminate metabolically healthy from unhealthy obesity. In positive energy balance, a decreased capacity to expand SAT may drive lipid accumulation to visceral adipose tissue, liver and skeletal muscle. This state of lipotoxicity is associated with chronic low-grade inflammation, insulin resistance and dyslipidaemia. The present review examines the differential adipose tissue development and function in children and adolescents who exhibit metabolic dysregulation compared with those who are protected. Additionally, the role of manipulating dietary fat quality to potentially prevent and treat metabolic dysfunction in obesity will be discussed. The findings of the present review highlight the need for further randomised controlled trials to establish the effect of dietary n-3 PUFA on the metabolic phenotype of obese children and adolescents. Furthermore, using a personalised nutrition approach to target interventions to those at risk of, or those with established metabolic dysregulation may optimise the efficacy of modifying dietary fat quality.

Approaches for drawing causal inferences from epidemiological birth cohorts: a review

Large-scale population-based birth cohorts, which recruit women during pregnancy or at birth and follow up their offspring through infancy and into childhood and adolescence, provide the opportunity to monitor and model early life exposures in relation to developmental characteristics and later life outcomes. However, due to confounding and other limitations, identification of causal risk factors has proved challenging and published findings are often not reproducible. A suite of methods has been developed in recent years to minimise problems afflicting observational epidemiology, to strengthen causal inference and to provide greater insights into modifiable intra-uterine and early life risk factors. The aim of this review is to describe these causal inference methods and to suggest how they may be applied in the context of birth cohorts and extended along with the development of birth cohort consortia and expansion of "omic" technologies.

In utero exposure to prepregnancy maternal obesity and postweaning high-fat diet impair regulators of mitochondrial dynamics in rat placenta and offspring

The proportion of pregnant women who are obese at conception continues to rise. Compelling evidence suggests the intrauterine environment is an important determinant of offspring health. Maternal obesity and unhealthy diets are shown to promote metabolic programming in the offspring. Mitochondria are maternally inherited, and we have previously shown impaired mitochondrial function in rat offspring exposed to maternal obesity in utero. Mitochondrial health is maintained by mitochondrial dynamics, or the processes of fusion and fission, which serve to repair damaged mitochondria, remove irreparable mitochondria, and maintain mitochondrial morphology. An imbalance between fusion and fission has been associated with obesity, insulin resistance, and reproduction complications. In the present study, we examined the influence of maternal obesity and postweaning high-fat diet (HFD) on key regulators of mitochondrial fusion and fission in rat offspring at important developmental milestones which included postnatal day (PND)35 (2 wk HFD) and PND130 (∼16 wk HFD). Our results indicate HFD-fed offspring had reduced mRNA expression of presenilin-associated rhomboid-like (PARL), optic atrophy (OPA)1, mitofusin (Mfn)1, Mfn2, fission (Fis)1, and nuclear respiratory factor (Nrf)1 at PND35, while OPA1 and Mfn2 remained decreased at PND130. Putative transcriptional regulators of mitochondrial dynamics were reduced in rat placenta and offspring liver and skeletal muscle [peroxisome proliferator-activated receptor gamma coactivator (PGC1)α, PGC1β, and estrogen-related receptor (ERR)α], consistent with indirect calorimetry findings revealing reduced energy expenditure and impaired fat utilization. Overall, maternal obesity detrimentally alters mitochondrial targets that may contribute to impaired mitochondrial health and increased obesity susceptibility in later life.

Epigenetics and life-long consequences of an adverse nutritional and diabetic intrauterine environment

The phenomenon that adverse environmental exposures in early life are associated with increased susceptibilities for many adult, particularly metabolic diseases, is now referred to as ‘developmental origins of health and disease (DOHAD)’ or ‘Barker’ hypothesis. Fetal overnutrition and undernutrition have similar long-lasting effects on the setting of the neuroendocrine control systems, energy homeostasis, and metabolism, leading to life-long increased morbidity. There are sensitive time windows during early development, where environmental cues can program persistent epigenetic modifications which are generally assumed to mediate these gene–environment interactions. Most of our current knowledge on fetal programing comes from animal models and epidemiological studies in humans, in particular the Dutch famine birth cohort. In industrialized countries, there is more concern about adverse long-term consequences of fetal overnutrition, i.e. by exposure to gestational diabetes mellitus and/or maternal obesity which affect 10–20% of pregnancies. Epigenetic changes due to maternal diabetes/obesity may predispose the offspring to develop metabolic disease later in life and, thus, transmit the adverse environmental exposure to the next generation. This vicious cycle could contribute significantly to the worldwide metabolic disease epidemics. In this review article, we focus on the epigenetics of an adverse intrauterine environment, in particular gestational diabetes, and its implications for the prevention of complex disease.