Developmental programming by maternal obesity: Lessons from animal models

Prenatal maternal diabetes, comorbidities, and risk for neurodevelopmental impairment in the first two years

BACKGROUND

Maternal diabetes is a known risk for neurodevelopmental delay in offspring, and often presents with comorbid metabolic conditions, such as obesity and hypertension. However, their combined effects on neurodevelopmental outcomes remain unclear. We investigated the independent and combined associations of maternal diabetes and comorbidities with the risk of neurodevelopmental delay in children aged 12 and 24 months.

METHODS

A prospective longitudinal cohort of children from Pregnancy during the COVID-19 Pandemic study. Neurodevelopmental screening at 12 and 24 months was conducted using the Ages and Stages Questionnaire, which assesses domain-specific development.

RESULTS

Maternal diabetes was not associated with neurodevelopmental risks either at 12 or 24 months. However, in combined analyses, maternal diabetes and pre-pregnancy overweight were associated with an increased risk of neurodevelopmental delay in personal-social skills (odds ratio [OR], 1.75 [95%CI,1.01-3.01]) at 24 months, though not at 12 months. Maternal diabetes and pre-pregnancy obesity were also associated with an increased risk for neurodevelopmental delay in communication (OR, 1.71 [95%CI,1.01-2.82]) and personal-social skills (OR, 2.01 [95%CI,1.03-3.73]) at 24 months. Furthermore, maternal diabetes and hypertensive disorders of pregnancy (HDP) had higher rates of positive screening for delay in fine-motor skills (OR, 3.54 [95%CI, 1.28-8.41]) at 12 months but not at 24 months. Post-hoc analysis revealed an independent association of maternal pre-pregnancy obesity, but not overweight, with an increased risk of neurodevelopmental delay in communication, fine-motor, and personal-social skills (ORs ranging from 1.44 to 1.71) at 24 months but not 12 months. Similarly, there was an independent association of maternal HDP with an increased risk of neurodevelopmental delay in fine-motor and and personal-social skills (ORs ranging from 2.01 to 2.19) at 24 months.

CONCLUSION

Maternal diabetes with comorbid conditions is likely to increase the risk of neurodevelopmental delay during infancy than individual exposure, suggesting the persistent influence of prenatal exposure on offspring neurodevelopment.

IMPACT

1. Identifying modifiable prenatal risk factors for neurodevelopmental impairment in offspring is crucial for targeted interventions and providing support to mothers during pregnancy, which can lead to improved child health outcomes. 2. Maternal diabetes was not associated with neurodevelopmental delays in children at 12 or 24 months. 3. Maternal diabetes in combination with pre-pregnancy overweight or obesity increased the risk of cognitive delay at 24 months. 4. Maternal pre-pregnancy obesity but not overweight, and hypertensive disorders of pregnancy independently increased risks of cognitive and motor delays at 24 months.

Paternal obesity induces changes in sperm chromatin accessibility and has a mild effect on offspring metabolic health

The increasing global burden of metabolic disorders including obesity and diabetes necessitates a comprehensive understanding of their etiology, which not only encompasses genetic and environmental factors but also parental influence. Recent evidence has unveiled paternal obesity as a contributing factor to offspring's metabolic health via sperm epigenetic modifications. In this study, we investigated the impact of a Western diet-induced obesity in C57BL/6 male mice on sperm chromatin accessibility and the subsequent metabolic health of their progeny. Utilizing Assay for Transposase-Accessible Chromatin with sequencing, we discovered 450 regions with differential accessibility in sperm from obese fathers, implicating key developmental and metabolic pathways. Contrary to expectations, these epigenetic alterations in sperm were not predictive of long-term metabolic disorders in offspring, who exhibited only mild transient metabolic changes early in life. Both male and female F1 progeny showed no enduring predisposition to obesity or diabetes. These results underscore the biological resilience of offspring to paternal epigenetic inheritance, suggesting a complex interplay between inherited epigenetic modifications and the offspring's own developmental compensatory mechanisms. This study calls for further research into the biological processes that confer this resilience, which could inform interventional strategies to combat the heritability of metabolic diseases.

High-Fat Diets Fed during Pregnancy Cause Changes to Pancreatic Tissue DNA Methylation and Protein Expression in the Offspring: A Multi-Omics Approach

Maternal obesity, caused by diets rich in fats and sugars during pregnancy, can predispose offspring to metabolic diseases such as diabetes. We hypothesized that obesity during pregnancy leads to increased DNA methylation and reduced protein expression in factors regulating β-cell function and apoptosis. Female C57BL/6J mice were fed a high-fat diet (HFD; 42% fat content; n = 3) or a control diet (CON; 16% fat content; n = 3) for fourteen weeks before and during pregnancy. Offspring were euthanized at 8 weeks and pancreatic tissue was collected. Isolated DNA was analyzed using whole-genome bisulfite sequencing. Protein expression was quantified using LC-MS. No significant differences in body weight were observed between HFD and control pups (p = 0.10). Whole-genome bisulfite sequencing identified 91,703 and 88,415 differentially methylated regions (DMRs) in CON vs. HFD male and female offspring. A total of 34 and 4 proteins were determined to have changes in expression that correlated with changes in DNA methylation in CON vs. HFD males and females, respectively. The majority of these factors were grouped into the metabolic function category via pathway analyses. This study illustrates the complex relationship between epigenetics, diet, and sex-specific responses, therefore offering insights into potential therapeutic targets and areas for further research.

Late-in-life Exercise Ameliorates the Aging Trajectory Metabolism Programmed by Maternal Obesity in Rats: It is Never Too Late

BACKGROUND

Maternal obesity (MO) has been shown to adversely affect metabolic, oxidative, reproductive, and cognitive function in offspring. However, it is unclear whether lifestyle modification can ameliorate the metabolic and organ dysfunction programmed by MO and prevent the effects of metabolic syndrome in adulthood. This study aimed to evaluate whether moderate voluntary exercise in the offspring of rats born to obese mothers can ameliorate the adverse effects of MO programming on metabolism and liver function in mid-adulthood.

METHODS

Offspring of control (CF1) and MOF1 mothers were fed with a control diet from weaning. Adult males and females participated in 15 min exercise sessions five days/week. Metabolic parameters were analyzed before and after the exercise intervention. Liver oxidative stress biomarkers and antioxidant enzymes were analyzed before and after the intervention.

RESULTS

Males showed that CF1ex ran more than MOF1ex and increased the distance covered. In contrast, females in both groups ran similar distances and remained constant but ran more distance than males. At PND 300 and 450, male and female MOF1 had higher leptin, triglycerides, insulin, and HOMA-IR levels than CF1. However, male MOF1ex had lower triglycerides, insulin, and HOMA-IR levels than MOF1. Improvements in liver fat and antioxidant enzymes were observed in CF1ex and MOF1ex males and females compared to their respective CF1 and MOF1 groups.

CONCLUSION

These findings suggest that moderate voluntary exercise, even when started in mid-adulthood, can improve metabolic outcomes and delay accelerated metabolic aging in MO-programmed rats in a sex-dependent manner.

Inflammation as a Sex-Specific Mediator in the Relationship between Maternal and Offspring Obesity in C57Bl/6J Mice

Maternal obesity is a well-established risk factor for offspring obesity development. The relationship between maternal and offspring obesity is mediated in part by developmental programming of offspring metabolic circuitry, including hypothalamic signaling. Dysregulated hypothalamic inflammation has also been linked to development of obesity. We utilized an established C57Bl/6J mouse model of high-fat, high-sugar diet induced maternal obesity to evaluate the effect of maternal obesity on systemic and hypothalamic TNF-α, IL-6, and IL-1β levels in neonatal and adult offspring. The offspring of dams with obesity demonstrated increased adiposity and decreased activity compared to control offspring. Maternal obesity was associated with decreased plasma TNF-α, IL-6 and IL-1β in adult female offspring and decreased plasma IL-6 in neonatal male offspring. Neonatal female offspring of obese dams had decreased TNF-α gene expression in the hypothalamus compared to control females, while neonatal and adult male offspring of obese dams had decreased IL-6 gene expression in the hypothalamus compared to control males. In summary, our results highlight important sex differences in the inflammatory phenotype of offspring exposed to maternal obesity. Sex-specific immunomodulatory mechanisms should be considered in future efforts to develop therapeutic interventions for obesity prevention and treatment.

Adult rats sired by obese fathers present learning deficits associated with epigenetic and neurochemical alterations linked to impaired brain glutamatergic signaling

AIM

Offspring of obese mothers are at high risk of developing metabolic syndrome and cognitive disabilities. Impaired metabolism has also been reported in the offspring of obese fathers. However, whether brain function can also be affected by paternal obesity has barely been examined. This study aimed to characterize the learning deficits resulting from paternal obesity versus those induced by maternal obesity and to identify the underlying mechanisms.

METHODS

Founder control and obese female and male Wistar rats were mated to constitute three first-generation (F1) experimental groups: control mother/control father, obese mother/control father, and obese father/control mother. All F1 animals were weaned onto standard chow and underwent a learning test at 4 months of age, after which several markers of glutamate-mediated synaptic plasticity together with the expression of miRNAs targeting glutamate receptors and the concentration of kynurenic and quinolinic acids were quantified in the hippocampus and frontal cortex.

RESULTS

Maternal obesity induced a severe learning deficit by impairing memory encoding and memory consolidation. The offspring of obese fathers also showed reduced memory encoding but not impaired long-term memory formation. Memory deficits in offspring of obese fathers and obese mothers were associated with a down-regulation of genes encoding NMDA glutamate receptors subunits and several learning-related genes along with impaired expression of miR-296 and miR-146b and increased concentration of kynurenic acid.

CONCLUSION

Paternal and maternal obesity impair offspring's learning abilities by affecting different processes of memory formation. These cognitive deficits are associated with epigenetic and neurochemical alterations leading to impaired glutamate-mediated synaptic plasticity.

Pregnancy Protects against Abnormal Gut Permeability Promoted via the Consumption of a High-Fat Diet in Mice

The consumption of large amounts of dietary fats and pregnancy are independent factors that can promote changes in gut permeability and the gut microbiome landscape. However, there is limited evidence regarding the impact of pregnancy on the regulation of such parameters in females fed a high-fat diet. Here, gut permeability and microbiome landscape were evaluated in a mouse model of diet-induced obesity in pregnancy. The results show that pregnancy protected against the harmful effects of the consumption of a high-fat diet as a disruptor of gut permeability; thus, there was a two-fold reduction in FITC-dextran passage to the bloodstream compared to non-pregnant mice fed a high-fat diet (p < 0.01). This was accompanied by an increased expression of gut barrier-related transcripts, particularly in the ileum. In addition, the beneficial effect of pregnancy on female mice fed the high-fat diet was accompanied by a reduced presence of bacteria belonging to the genus Clostridia, and by increased Lactobacillus murinus in the gut (p < 0.05). Thus, this study advances the understanding of how pregnancy can act during a short window of time, protecting against the harmful effects of the consumption of a high-fat diet by promoting an increased expression of transcripts encoding proteins involved in the regulation of gut permeability, particularly in the ileum, and promoting changes in the gut microbiome.

Obesity during Pregnancy in the Horse: Effect on Term Placental Structure and Gene Expression, as Well as Colostrum and Milk Fatty Acid Concentration

In horses, the prevalence of obesity is high and associated with serious metabolic pathologies. Being a broodmare has been identified as a risk factor for obesity. In other species, maternal obesity is known to affect the development of the offspring. This article is a follow-up study of previous work showing that Obese mares (O, n = 10, body condition score > 4.25 at insemination) were more insulin resistant and presented increased systemic inflammation during pregnancy compared to Normal mares (N, n = 14, body condition score < 4 at insemination). Foals born to O mares were more insulin-resistant, presented increased systemic inflammation, and were more affected by osteoarticular lesions. The objective of the present study was to investigate the effect of maternal obesity on placental structure and function, as well as the fatty acid profile in the plasma of mares and foals, colostrum, and milk until 90 days of lactation, which, to our knowledge, has been poorly studied in the horse. Mares from both groups were fed the same diet during pregnancy and lactation. During lactation, mares were housed in pasture. A strong heat wave, followed by a drought, occurred during their 2nd and 3rd months of lactation (summer of 2016 in the Limousin region, France). In the present article, term placental morphometry, structure (stereology), and gene expression (RT-qPCR, genes involved in nutrient transport, growth, and development, as well as vascularization) were studied. Plasma of mares and their foals, as well as colostrum and milk, were sampled at birth, 30 days, and 90 days of lactation. The fatty acid composition of these samples was measured using gas chromatography. No differences between the N and O groups were observed for term placental morphometry, structure, or gene expression. No difference in plasma fatty acid composition was observed between groups in mares. The plasma fatty acid profile of O foals was more pro-inflammatory and indicated an altered placental lipid metabolism between birth and 90 days of age. These results are in line with the increased systemic inflammation and altered glucose metabolism observed until 18 months of age in this group. The colostrum fatty acid profile of O mares was more pro-inflammatory and indicated an increased transfer and/or desaturation of long-chain fatty acids. Moreover, O foals received a colostrum poorer in medium-chain saturated fatty acid, a source of immediate energy for the newborn that can also play a role in immunity and gut microbiota development. Differences in milk fatty acid composition indicated a decreased ability to adapt to heat stress in O mares, which could have further affected the metabolic development of their foals. In conclusion, maternal obesity affected the fatty acid composition of milk, thus also influencing the foal's plasma fatty acid composition and likely participating in the developmental programming observed in growing foals.

Effect of a Diet-Induced Obesity on the Progeny Response in a Murine Model

Diet-induced obesity could have detrimental effects on adults and their progeny. The aim of this study was to determine the effect of a high-energy diet on both F1 mice body weight and tissue/organ weight and F2 offspring growth. A simple murine model for obesity was developed using a high-energy diet and mice reared in litters of five or ten, from 30 dams receiving a cafeteria diet of either commercial chow (low energy), or a mixture of commercial chow, chocolate (50% cacao), and salty peanuts (high energy). This diet continued from mating until weaning, when the pups were allocated according to sex into eight groups based on maternal diet, litter size, and post-weaning diet. On day 74, the males were slaughtered, and the females were bred then slaughtered after lactation. As a result, the high-energy maternal diet increased the F1 offspring growth during lactation, while the high-energy post-weaning diet increased the F1 adult body weight and tissue/organ weight. The high-energy maternal diet could negatively affect the onset of the F1 but not the maintenance of breastfeeding of F1 and F2 offspring. For F2 offspring growth, the high energy overlapped the low-energy post-weaning diet, due to problems of gaining weight during lactation.

Thermoneutral Housing Enables Studies of Vertical Transmission of Obesogenic Diet-Driven Metabolic Diseases

Vertical transmission of obesity is a critical contributor to the unabated obesity pandemic and the associated surge in metabolic diseases. Existing experimental models insufficiently recapitulate "human-like" obesity phenotypes, limiting the discovery of how severe obesity in pregnancy instructs vertical transmission of obesity. Here, via utility of thermoneutral housing and obesogenic diet feeding coupled to syngeneic mating of WT obese female and lean male mice on a C57BL/6 background, we present a tractable, more "human-like" approach to specifically investigate how maternal obesity contributes to offspring health. Using this model, we found that maternal obesity decreased neonatal survival, increased offspring adiposity, and accelerated offspring predisposition to obesity and metabolic disease. We also show that severe maternal obesity was sufficient to skew offspring microbiome and create a proinflammatory gestational environment that correlated with inflammatory changes in the offspring in utero and adulthood. Analysis of a human birth cohort study of mothers with and without obesity and their infants was consistent with mouse study findings of maternal inflammation and offspring weight gain propensity. Together, our results show that dietary induction of obesity in female mice coupled to thermoneutral housing can be used for future mechanistic interrogations of obesity and metabolic disease in pregnancy and vertical transmission of pathogenic traits.

Long-chain n-3 PUFA given before and throughout gestation and lactation in rats prevent high-fat diet-induced insulin resistance in male offspring in a tissue-specific manner

This study investigated whether long-chain n-3 PUFA (LC n-3 PUFA) given to pregnant rats fed a high-fat (HF) diet may prevent fetal programming in male offspring at adulthood. Six weeks before mating, and throughout gestation and lactation, female nulliparous Sprague-Dawley rats were given a chow (C) diet, HF (60·6 % fat from maize, rapeseed oils and lard) or HF in which one-third of fat was replaced by fish oil (HF n-3). At weaning, the three offspring groups were randomly separated in two groups fed C diet, or HF without LC n-3 PUFA, for 7 weeks until adulthood. Glucose tolerance and insulin sensitivity were assessed by an oral glucose tolerance test both at weaning and at adulthood. Insulin signalling was determined in liver, muscle and adipose tissue by quantification of the phosphorylation of Akt on Ser 473 at adulthood. At weaning, as at adulthood, offspring from HF-fed dams were obese and displayed glucose intolerance (GI) and insulin resistance (IR), but not those from HFn-3 fed dams. Following the post-weaning C diet, phosphorylation of Akt was strongly reduced in all tissues of offspring from HF dams, but to a lesser extent in liver and muscle of offspring from HFn-3 dams. However, it was abolished in all tissues of all offspring groups fed the HF post-weaning diet. Thus, LC n-3 PUFA introduced in a HF in dams partially prevented the transmission of GI and IR in adult offspring even though they were fed without LC n-3 PUFA from weaning.

Maternal obesity and high leptin levels prime pro-inflammatory pathways in human cord blood leukocytes

INTRODUCTION

Maternal obesity alters the immune function in the offspring. We hypothesize that maternal obesity and pro-inflammatory pathways induce leptin-related genes in neonatal monocytes, whereby high leptin levels enhance their inflammatory response.

METHODS

Transcriptional profiles of cord blood leukocytes (CBL) in basal and pro-inflammatory conditions were studied to determine differentially expressed genes (DEG). The DNA methylation profile of CB monocytes (CBM) of neonates born to control BMI mothers and women with obesity was assayed to identify differentially methylated probes (DMP). CBM-derived macrophages were cultured with or without leptin (10-100 ng/ml) and then stimulated with lipopolysaccharide (LPS, 100 ng/ml) and interferon-gamma (20 ng/ml) to assess the induction of TNF-α and IL-10 transcripts.

RESULTS

CBL from pregnancies with obesity (CBL-Ob) showed 12,183 DEG, affecting 49 out of 78 from the leptin pathway. Control CBM exposed to LPS showed 45 leptin-related DEG, an effect prevented by the co-exposure to LPS and IL-10. Conversely, CBM-Ob showed 5279 DMP enriched in insulin- and leptin-related genes, and Lasso regression of leptin-related DMP showed high predictive value for plasma leptin levels (r2 = 0.9897) and maternal BMI categories (AUC = 1). Chronic exposure to leptin increased TNF-α and decreased IL-10 levels in control BMI samples but not in Ob-CBM. Enhanced TNF-α induction after proinflammatory stimulation was observed in leptin-treated control BMI samples.

DISCUSSION

Obesity in pregnancy is associated with a distinctive expression and DNA methylation profile of leptin-related genes in cord blood monocytes, meanwhile, leptin enhances the expression of pro-inflammatory cytokines upon stimulation with M1-skewing agents.

Metabolic and feeding adjustments during pregnancy

Eating behaviours are determined by the integration of interoceptive and environmental inputs. During pregnancy, numerous physiological adaptations take place in the maternal organism to provide an adequate environment for embryonic growth. Among them, whole-body physiological remodelling directly influences eating patterns, commonly causing notable taste perception alterations, food aversions and cravings. Recurrent food cravings for and compulsive eating of highly palatable food can contribute to the development and maintenance of gestational overweight and obesity with potential adverse health consequences for the offspring. Although much is known about how maternal eating habits influence offspring health, the mechanisms that underlie changes in taste perception and food preference during pregnancy (which guide and promote feeding) are only just starting to be elucidated. Given the limited and diffuse understanding of the neurobiology of gestational eating patterns, the aim of this Review is to compile, integrate and discuss the research conducted on this topic in both experimental models and humans. This article sheds light on the mechanisms that drive changes in female feeding behaviours during distinct physiological states. Understanding these processes is crucial to improve gestational parent health and decrease the burden of metabolic and food-related diseases in future generations.

Control of energy homeostasis by the lateral hypothalamic area

The lateral hypothalamic area (LHA) is a subcortical brain region that exerts control over motivated behavior, feeding, and energy balance across species. Recent single-cell sequencing studies have defined at least 30 distinct LHA neuron types. Some of these influence specific aspects of energy homeostasis; however, the functions of many LHA cell types remain unclear. This review addresses the rapidly emerging evidence from cell-type-specific investigations that the LHA leverages distinct neuron populations to regulate energy balance through complex connections with other brain regions. It will highlight recent findings demonstrating that LHA control of energy balance extends beyond mere food intake and propose outstanding questions to be addressed by future research.

Made in the Womb: Maternal Programming of Offspring Cardiovascular Function by an Obesogenic Womb

Obesity incidence has been increasing at an alarming rate, especially in women of reproductive age. It is estimated that 50% of pregnancies occur in overweight or obese women. It has been described that maternal obesity (MO) predisposes the offspring to an increased risk of developing many chronic diseases in an early stage of life, including obesity, type 2 diabetes, and cardiovascular disease (CVD). CVD is the main cause of death worldwide among men and women, and it is manifested in a sex-divergent way. Maternal nutrition and MO during gestation could prompt CVD development in the offspring through adaptations of the offspring's cardiovascular system in the womb, including cardiac epigenetic and persistent metabolic programming of signaling pathways and modulation of mitochondrial metabolic function. Currently, despite diet supplementation, effective therapeutical solutions to prevent the deleterious cardiac offspring function programming by an obesogenic womb are lacking. In this review, we discuss the mechanisms by which an obesogenic intrauterine environment could program the offspring's cardiovascular metabolism in a sex-divergent way, with a special focus on cardiac mitochondrial function, and debate possible strategies to implement during MO pregnancy that could ameliorate, revert, or even prevent deleterious effects of MO on the offspring's cardiovascular system. The impact of maternal physical exercise during an obesogenic pregnancy, nutritional interventions, and supplementation on offspring's cardiac metabolism are discussed, highlighting changes that may be favorable to MO offspring's cardiovascular health, which might result in the attenuation or even prevention of the development of CVD in MO offspring. The objectives of this manuscript are to comprehensively examine the various aspects of MO during pregnancy and explore the underlying mechanisms that contribute to an increased CVD risk in the offspring. We review the current literature on MO and its impact on the offspring's cardiometabolic health. Furthermore, we discuss the potential long-term consequences for the offspring. Understanding the multifaceted effects of MO on the offspring's health is crucial for healthcare providers, researchers, and policymakers to develop effective strategies for prevention and intervention to improve care.

Maternal overnutrition is associated with altered synaptic input to lateral hypothalamic area

OBJECTIVE

Maternal overnutrition is associated with adverse outcomes in offspring, including increased risk for obesity and diabetes. Here, we aim to test the effects of maternal obesity on lateral hypothalamic feeding circuit function and determine the relationship with body weight regulation.

METHODS

Using a mouse model of maternal obesity, we assessed how perinatal overnutrition affected food intake and body weight regulation in adult offspring. We then used channelrhodopsin-assisted circuit mapping and electrophysiological recordings to assess the synaptic connectivity within an extended amygdala-lateral hypothalamic pathway.

RESULTS

We show that maternal overnutrition during gestation and throughout lactation produces offspring that are heavier than controls prior to weaning. When weaned onto chow, the body weights of over-nourished offspring normalize to control levels. However, when presented with highly palatable food as adults, both male and female maternally over-nourished offspring are highly susceptible to diet-induced obesity. This is associated with altered synaptic strength in an extended amygdala-lateral hypothalamic pathway, which is predicted by developmental growth rate. Additionally, lateral hypothalamic neurons receiving synaptic input from the bed nucleus of the stria terminalis have enhanced excitatory input following maternal overnutrition which is predicted by early life growth rate.

CONCLUSIONS

Together, these results demonstrate one way in which maternal obesity rewires hypothalamic feeding circuits to predispose offspring to metabolic dysfunction.

Maternal obesity and offspring health: Adapting metabolic changes through autophagy and mitophagy

Maternal obesity leads to obstetric complications and a high prevalence of metabolic anomalies in the offspring. Among various contributing factors for maternal obesity-evoked health sequelae, developmental programming is considered as one of the leading culprit factors for maternal obesity-associated chronic comorbidities. Although a unified theory is still lacking to systematically address multiple unfavorable postnatal health sequelae, a cadre of etiological machineries have been put forward, including lipotoxicity, inflammation, oxidative stress, autophagy/mitophagy defect, and cell death. Hereinto, autophagy and mitophagy play an essential housekeeping role in the clearance of long-lived, damaged, and unnecessary cell components to maintain and restore cellular homeostasis. Defective autophagy/mitophagy has been reported in maternal obesity and negatively impacts fetal development and postnatal health. This review will provide an update on metabolic disorders in fetal development and postnatal health issues evoked by maternal obesity and/or intrauterine overnutrition and discuss the possible contribution of autophagy/mitophagy in metabolic diseases. Moreover, relevant mechanisms and potential therapeutic strategies will be discussed in an effort to target autophagy/mitophagy and metabolic disturbances in maternal obesity.

Genetic Obesity in Pregnant Ay Mice Does Not Affect Susceptibility to Obesity and Food Choice in Offspring

Maternal diet and obesity (MO) may influence taste preferences and increase the susceptibility to obesity in offspring, but the impact of MO per se to these influences is poorly understood. We evaluated the influence of MO on food choice and susceptibility to obesity in offspring when mothers consumed a standard diet (SD). Mice with the Lethal yellow mutation (Ay/a) develop obesity consuming an SD. Metabolic parameters were assessed in pregnant and lactating Ay/a (obesity) and a/a (control) mothers. Metabolic response to the consumption of a sweet–fat diet (SFD: SD, lard, and sweet biscuits) and the choice of components of this diet were evaluated in their male and female offspring. Compared to control mothers, pregnant obese mothers had higher levels of insulin, leptin, and FGF21. MO increased food intake and liver expression of lipogenesis genes in male offspring consuming the SD. SFD consumption caused obesity development and insulin resistance, increased liver expression of glycolytic and lipogenesis genes, and affected hypothalamic expression of anorexigenic and orexigenic genes. In offspring of both sexes, MO had no effect on food choice and metabolic response to SFD intake. Therefore, when obese mothers consume a balanced diet, MO does not affect food choice and development of diet-induced obesity in offspring.

lncRNA‑miRNA‑mRNA network in female offspring born from obese dams

Maternal obesity is associated with disturbance of lipid metabolism and obesity in offspring; however, the pathogenesis is still unclear. The present study elucidated the role of potential lipid metabolism-associated long non-coding RNA (lncRNA) and identified the pathways involved in mice born to obese dams. In the present study, maternal obesity was induced by feeding a high-fat diet for 10 weeks in female C57/BL6 mice, whereas control mice were fed a standard diet. All female mice mated with healthy male mice and were allowed to deliver spontaneously. The results demonstrated that female offspring from obese dams presented a tendency to become overweight in the first 8 weeks after birth; however, maternal obesity did not significantly alter the body weight of male offspring. RNA-sequencing analysis was performed on female offspring liver at 3 weeks old. Significantly dysregulated lncRNAs and downstream targets in female offspring liver were identified using bioinformatics analysis. lncRNA, microRNA (miRNA or miR) and mRNA expression levels in liver and AML12 cells were assessed using reverse transcription-quantitative PCR. A total of 8 upregulated and 17 downregulated lncRNAs were demonstrated in offspring from obese dams and lncRNA Lockd was indicated to be a key dysregulated lncRNA. Competing endogenous RNA (ceRNA) models suggested that the lncRNA Lockd/miR-582-5p/Elovl5 pathway was key for lipid metabolism in the liver of offspring from obese dams. Finally, small interfering RNA and miRNA inhibitor transfection was used to evaluate the ceRNA models in AML12 cells. Taken together, the results of the present study indicated that lncRNA Lockd-miR-582-5p-Elovl5 network may be disrupted in lipid metabolism and lead to obesity in the offspring of obese dams. This research will provide new insights into the molecular mechanism of obesity and lipid metabolism disorder.

Maternal obesity and programming of metabolic syndrome in the offspring: searching for mechanisms in the adipocyte progenitor pool

BACKGROUND

It is now understood that it is the quality rather than the absolute amount of adipose tissue that confers risk for obesity-associated disease. Adipose-derived stem cells give rise to adipocytes during the developmental establishment of adipose depots. In adult depots, a reservoir of progenitors serves to replace adipocytes that have reached their lifespan and for recruitment to increase lipid buffering capacity under conditions of positive energy balance. MAIN: The adipose tissue expandability hypothesis posits that a failure in de novo differentiation of adipocytes limits lipid storage capacity and leads to spillover of lipids into the circulation, precipitating the onset of obesity-associated disease. Since adipose progenitors are specified to their fate during late fetal life, perturbations in the intrauterine environment may influence the rapid expansion of adipose depots that occurs in childhood or progenitor function in established adult depots. Neonates born to mothers with obesity or diabetes during pregnancy tend to have excessive adiposity at birth and are at increased risk for childhood adiposity and cardiometabolic disease.

CONCLUSION

In this narrative review, we synthesize current knowledge in the fields of obesity and developmental biology together with literature from the field of the developmental origins of health and disease (DOHaD) to put forth the hypothesis that the intrauterine milieu of pregnancies complicated by maternal metabolic disease disturbs adipogenesis in the fetus, thereby accelerating the trajectory of adipose expansion in early postnatal life and predisposing to impaired adipose plasticity.

Maternal obesity damages the median eminence blood-brain barrier structure and function in the progeny: the beneficial impact of cross-fostering by lean mothers

Maternal obesity is an important risk factor for obesity, cardiovascular, and metabolic diseases in the offspring. Studies have shown that it leads to hypothalamic inflammation in the progeny, affecting the function of neurons regulating food intake and energy expenditure. In adult mice fed a high-fat diet, one of the hypothalamic abnormalities that contribute to the development of obesity is the damage of the blood-brain barrier (BBB) at the median eminence-arcuate nucleus (ME-ARC) interface; however, how the hypothalamic BBB is affected in the offspring of obese mothers requires further investigation. Here, we used confocal and transmission electron microscopy, transcript expression analysis, glucose tolerance testing, and a cross-fostering intervention to determine the impact of maternal obesity and breastfeeding on BBB integrity at the ME-ARC interface. The offspring of obese mothers were born smaller; conversely, at weaning, they presented larger body mass and glucose intolerance. In addition, maternal obesity-induced structural and functional damage of the offspring's ME-ARC BBB. By a cross-fostering intervention, some of the defects in barrier integrity and metabolism seen during development in an obesogenic diet were recovered. The offspring of obese dams breastfed by lean dams presented a reduction of body mass and glucose intolerance as compared to the offspring continuously exposed to an obesogenic environment during intrauterine and perinatal life; this was accompanied by partial recovery of the anatomical structure of the ME-ARC interface, and by the normalization of transcript expression of genes coding for hypothalamic neurotransmitters involved in energy balance and BBB integrity. Thus, maternal obesity promotes structural and functional damage of the hypothalamic BBB, which is, in part, reverted by lactation by lean mothers.NEW & NOTEWORTHY Maternal dietary habits directly influence offspring health. In this study, we aimed at determining the impact of maternal obesity on BBB integrity. We show that DIO offspring presented a leakier ME-BBB, accompanied by changes in the expression of transcripts encoding for endothelial and tanycytic proteins, as well as of hypothalamic neuropeptides. Breastfeeding in lean dams was sufficient to protect the offspring from ME-BBB disruption, providing a preventive strategy of nutritional intervention during early life.

Fat content in infant mesenchymal stem cells prospectively associates with childhood adiposity and fasting glucose

OBJECTIVE

In human studies, new model systems are needed for improved mechanistic investigation of developmental predisposition for metabolic disease but also to serve as benchmarks in early life prevention or intervention efforts. In this regard, human infant umbilical cord-derived mesenchymal stem cells (MSCs) are an emerging tool. However, long-term clinical relevance to in vivo markers of metabolic disease is unknown.

METHODS

In a cohort of 124 mother/child dyads, this study tested the hypothesis that triglyceride content (TG) of infant MSCs undergoing adipogenesis in vitro (MSC-TG) is associated with in vivo adiposity (percent fat mass) from birth to early childhood and with fasting glucose and insulin in early childhood.

RESULTS

MSC-TG was positively associated with in vivo child adiposity at birth, age 4 to 6 months, and age 4 to 6 years. MSC-TG was associated with fasting glucose, but not insulin, at 4 to 6 years. Importantly, MSC-TG explained an additional 13% variance in child adiposity at 4 to 6 years, after accounting for other established birth predictors (weight and percent fat mass at birth) and other established covariates related to child adiposity (e.g., breastfeeding exposure, physical activity).

CONCLUSIONS

This work demonstrates the strength of the MSC model for predicting offspring metabolic phenotype into childhood, even when considering the important contribution of other early life risk factors.

Maternal Supplementation with a Cocoa Extract during Lactation Deeply Modulates Dams' Metabolism, Increases Adiponectin Circulating Levels and Improves the Inflammatory Profile in Obese Rat Offspring

High-flavonoid cocoa consumption has been associated with beneficial properties. However, there are scarce data concerning the effects of maternal cocoa intake on dams and in their progeny. Here, we evaluated in rats whether maternal supplementation with a high-flavan-3-ol cocoa extract (CCX) during lactation (200 mg.kg^-1.day^-1) produced beneficial effects on dams and in their normoweight (STD-CCX group) and cafeteria-fed obese (CAF-CCX group) adult male offspring. Maternal intake of CCX significantly increased the circulating levels of adiponectin and decreased the mammary gland lipid content of dams. These effects were accompanied by increased energy expenditure and circulating free fatty acids, as well as by a higher expression of lipogenic and adiponectin-related genes in their mammary glands, which could be related to a compensatory mechanism to ensure enough lipid supply to the pups. CCX consumption programmed both offspring groups towards increased plasma total adiponectin levels, and decreased liver weight and lean/fat ratio. Furthermore, CAF-CCX progeny showed an improvement of the inflammatory profile, evidenced by the significant decrease of the monocyte chemoattractant protein-1 (MCP-1) circulating levels and the mRNA levels of the gene encoding the major histocompatibility complex, class II invariant chain (Cd74), a marker of M1 macrophage phenotype, in the epididymal white adipose tissue. Although further studies are needed, these findings can pave the way for using CCX as a nutraceutical supplement during lactation.

Sex-specific effects of maternal metformin intervention during glucose-intolerant obese pregnancy on body composition and metabolic health in aged mouse offspring

AIMS/HYPOTHESIS

Metformin is increasingly used to treat gestational diabetes (GDM) and pregnancies complicated by pregestational type 2 diabetes or polycystic ovary syndrome but data regarding long-term offspring outcome are lacking in both human studies and animal models. Using a mouse model, this study investigated the effects of maternal metformin intervention during obese glucose-intolerant pregnancy on adiposity, hepatic steatosis and markers of metabolic health of male and female offspring up to the age of 12 months.

METHODS

C57BL/6J female mice were weaned onto either a control diet (Con) or, to induce pre-conception obesity, an obesogenic diet (Ob). The respective diets were maintained throughout pregnancy and lactation. These obese dams were then randomised to the untreated group or to receive 300 mg/kg oral metformin hydrochloride treatment (Ob-Met) daily during pregnancy. In male and female offspring, body weights and body composition were measured from 1 month until 12 months of age, when serum and tissues were collected for investigation of adipocyte cellularity (histology), adipose tissue inflammation (histology and quantitative RT-PCR), and hepatic steatosis and fibrosis (histochemistry and modified Folch assay).

RESULTS

At 12 months of age, male Ob and Ob-Met offspring showed increased adiposity, adipocyte hypertrophy, elevated expression of proinflammatory genes, hyperleptinaemia and hepatic lipid accumulation compared with Con offspring. Male Ob-Met offspring failed to show hyperplasia between 8 weeks and 12 months, indicative of restricted adipose tissue expansion, resulting in increased immune cell infiltration and ectopic lipid deposition. Female Ob offspring were relatively protected from these phenotypes but Ob-Met female offspring showed increased adiposity, adipose tissue inflammation, hepatic lipid accumulation, hyperleptinaemia and hyperinsulinaemia compared with Con female offspring.

CONCLUSIONS/INTERPRETATION

Maternal metformin treatment of obese dams increased offspring metabolic risk factors in a sex- and age-dependent manner. These observations highlight the importance of following up offspring of both sexes beyond early adulthood after interventions during pregnancy. Our findings illustrate the complexity of balancing short-term benefits to mother and child vs any potential long-term metabolic effects on the offspring when prescribing therapeutic agents that cross the placenta.

Maternal obesity alters offspring liver and skeletal muscle metabolism in early post-puberty despite maintaining a normal post-weaning dietary lifestyle

Maternal obesity (MO) during pregnancy is linked to increased and premature risk of age-related metabolic diseases in the offspring. However, the underlying molecular mechanisms still remain not fully understood. Using a well-established nonhuman primate model of MO, we analyzed tissue biopsies and plasma samples obtained from post-pubertal offspring (3-6.5 y) of MO mothers (n = 19) and from control animals born to mothers fed a standard diet (CON, n = 13). All offspring ate a healthy chow diet after weaning. Using untargeted gas chromatography-mass spectrometry metabolomics analysis, we quantified a total of 351 liver, 316 skeletal muscle, and 423 plasma metabolites. We identified 58 metabolites significantly altered in the liver and 46 in the skeletal muscle of MO offspring, with 8 metabolites shared between both tissues. Several metabolites were changed in opposite directions in males and females in both liver and skeletal muscle. Several tissue-specific and 4 shared metabolic pathways were identified from these dysregulated metabolites. Interestingly, none of the tissue-specific metabolic changes were reflected in plasma. Overall, our study describes characteristic metabolic perturbations in the liver and skeletal muscle in MO offspring, indicating that metabolic programming in utero persists postnatally, and revealing potential novel mechanisms that may contribute to age-related metabolic diseases later in life.

Glucose and oxygen in the early intrauterine environment and their role in developmental abnormalities

The early life environment can have profound impacts on the developing conceptus in terms of both growth and morphogenesis. These impacts can manifest in a variety of ways, including congenital fetal anomalies, placental dysfunction with subsequent effects on fetal growth, and adverse perinatal outcomes, or via effects on long-term health outcomes that may not be detected until later childhood or adulthood. Two key examples of environmental influences on early development are explored: maternal hyperglycaemia and gestational hypoxia. These are increasingly common pregnancy exposures worldwide, with potentially profound impacts on population health. We explore what is known regarding the mechanisms by which these environmental exposures can impact early intrauterine development and thus result in adverse outcomes in the immediate, short, and long term.

The metabolic conditioning of obesity: A review of the pathogenesis of obesity and the epigenetic pathways that "program" obesity from conception

Understanding the developmental origins of health and disease is integral to overcome the global tide of obesity and its metabolic consequences, including atherosclerotic cardiovascular disease, type 2 diabetes, hyperlipidemia, and nonalcoholic fatty liver disease. The rising prevalence of obesity has been attributed, in part, to environmental factors including the globalization of the western diet and unhealthy lifestyle choices. In this review we argue that how and when such exposures come into play from conception significantly impact overall risk of obesity and later health outcomes. While the laws of thermodynamics dictate that obesity is caused by an imbalance between caloric intake and energy expenditure, the drivers of each of these may be laid down before the manifestation of the phenotype. We present evidence over the last half-century that suggests that the temporospatial evolution of obesity from intrauterine life and beyond is, in part, due to the conditioning of physiological processes at critical developmental periods that results in maladaptive responses to obesogenic exposures later in life. We begin the review by introducing studies that describe an association between perinatal factors and later risk of obesity. After a brief discussion of the pathogenesis of obesity, including the systemic regulation of appetite, adiposity, and basal metabolic rate, we delve into the mechanics of how intrauterine, postnatal and early childhood metabolic environments may contribute to adult obesity risk through the process of metabolic conditioning. Finally, we detail the specific epigenetic pathways identified both in preclinical and clinical studies that synergistically "program" obesity.

Dysregulation of Placental Lipid Hydrolysis by High-Fat/High-Cholesterol Feeding and Gestational Diabetes Mellitus in Mice

Advanced maternal age and obesity are the main risk factors to develop gestational diabetes mellitus (GDM). Obesity is a consequence of the increased storage of triacylglycerol (TG). Cytosolic and lysosomal lipid hydrolases break down TG and cholesteryl esters (CE) to release fatty acids (FA), free cholesterol, and glycerol. We have recently shown that intracellular lipases are present and active in the mouse placenta and that deficiency of lysosomal acid lipase alters placental and fetal lipid homeostasis. To date, intracellular lipid hydrolysis in GDM has been poorly studied despite the important role of FA in this condition. Therefore, we hypothesized that intracellular lipases are dysregulated in pregnancies complicated by maternal high-fat/high-cholesterol (HF/HCD) feeding with and without GDM. Placentae of HF/HCD-fed mice with and without GDM were more efficient, indicating increased nutrient transfer to the fetus. The increased activity of placental CE but not TG hydrolases in placentae of dams fed HF/HCD with or without GDM resulted in upregulated cholesterol export to the fetus and placental TG accumulation. Our results indicate that HF/HCD-induced dysregulation of placental lipid hydrolysis contributes to fetal hepatic lipid accumulation and possibly to fetal overgrowth, at least in mice.

The Legacy of Parental Obesity: Mechanisms of Non-Genetic Transmission and Reversibility

While a dramatic increase in obesity and related comorbidities is being witnessed, the underlying mechanisms of their spread remain unresolved. Epigenetic and other non-genetic mechanisms tend to be prominent candidates involved in the establishment and transmission of obesity and associated metabolic disorders to offspring. Here, we review recent findings addressing those candidates, in the context of maternal and paternal influences, and discuss the effectiveness of preventive measures.

Programming by maternal obesity: a pathway to poor cardiometabolic health in the offspring

There is an ever increasing prevalence of maternal obesity worldwide such that in many populations over half of women enter pregnancy either overweight or obese. This review aims to summarise the impact of maternal obesity on offspring cardiometabolic outcomes. Maternal obesity is associated with increased risk of adverse maternal and pregnancy outcomes. However, beyond this exposure to maternal obesity during development also increases the risk of her offspring developing long-term adverse cardiometabolic outcomes throughout their adult life. Both human studies and those in experimental animal models have shown that maternal obesity can programme increased risk of offspring developing obesity and adipose tissue dysfunction; type 2 diabetes with peripheral insulin resistance and β-cell dysfunction; CVD with impaired cardiac structure and function and hypertension via impaired vascular and kidney function. As female offspring themselves are therefore likely to enter pregnancy with poor cardiometabolic health this can lead to an inter-generational cycle perpetuating the transmission of poor cardiometabolic health across generations. Maternal exercise interventions have the potential to mitigate some of the adverse effects of maternal obesity on offspring health, although further studies into long-term outcomes and how these translate to a clinical context are still required.

Perinatal Obesity Induces Hepatic Growth Restriction with Increased DNA Damage Response, Senescence, and Dysregulated Igf-1-Akt-Foxo1 Signaling in Male Offspring of Obese Mice

Maternal obesity predisposes for hepato-metabolic disorders early in life. However, the underlying mechanisms causing early onset dysfunction of the liver and metabolism remain elusive. Since obesity is associated with subacute chronic inflammation and accelerated aging, we test the hypothesis whether maternal obesity induces aging processes in the developing liver and determines thereby hepatic growth. To this end, maternal obesity was induced with high-fat diet (HFD) in C57BL/6N mice and male offspring were studied at the end of the lactation [postnatal day 21 (P21)]. Maternal obesity induced an obese body composition with metabolic inflammation and a marked hepatic growth restriction in the male offspring at P21. Proteomic and molecular analyses revealed three interrelated mechanisms that might account for the impaired hepatic growth pattern, indicating prematurely induced aging processes: (1) Increased DNA damage response (γH2AX), (2) significant upregulation of hepatocellular senescence markers (Cdnk1a, Cdkn2a); and (3) inhibition of hepatic insulin/insulin-like growth factor (IGF)-1-AKT-p38-FoxO1 signaling with an insufficient proliferative growth response. In conclusion, our murine data demonstrate that perinatal obesity induces an obese body composition in male offspring with hepatic growth restriction through a possible premature hepatic aging that is indicated by a pathologic sequence of inflammation, DNA damage, senescence, and signs of a possibly insufficient regenerative capacity.

Food craving-like episodes during pregnancy are mediated by accumbal dopaminergic circuits

Preparation for motherhood requires a myriad of physiological and behavioural adjustments throughout gestation to provide an adequate environment for proper embryonic development¹. Cravings for highly palatable foods are highly prevalent during pregnancy² and contribute to the maintenance and development of gestational overweight or obesity³. However, the neurobiology underlying the distinct ingestive behaviours that result from craving specific foods remain unknown. Here we show that mice, similarly to humans, experience gestational food craving-like episodes. These episodes are associated with a brain connectivity reorganization that affects key components of the dopaminergic mesolimbic circuitry, which drives motivated appetitive behaviours and facilitates the perception of rewarding stimuli. Pregnancy engages a dynamic modulation of dopaminergic signalling through neurons expressing dopamine D2 receptors in the nucleus accumbens, which directly modulate food craving-like events. Importantly, persistent maternal food craving-like behaviour has long-lasting effects on the offspring, particularly in males, leading to glucose intolerance, increased body weight and increased susceptibility to develop eating disorders and anxiety-like behaviours during adulthood. Our results reveal the cognitively motivated nature of pregnancy food cravings and advocates for moderating emotional eating during gestation to prevent deterioration of the offspring's neuropsychological and metabolic health.

Western diet-induced shifts in the maternal microbiome are associated with altered microRNA expression in baboon placenta and fetal liver

Maternal consumption of a high-fat, Western-style diet (WD) disrupts the maternal/infant microbiome and contributes to developmental programming of the immune system and nonalcoholic fatty liver disease (NAFLD) in the offspring. Epigenetic changes, including non-coding miRNAs in the fetus and/or placenta may also underlie this risk. We previously showed that obese nonhuman primates fed a WD during pregnancy results in the loss of beneficial maternal gut microbes and dysregulation of cellular metabolism and mitochondrial dysfunction in the fetal liver, leading to a perturbed postnatal immune response with accelerated NAFLD in juvenile offspring. Here, we investigated associations between WD-induced maternal metabolic and microbiome changes, in the absence of obesity, and miRNA and gene expression changes in the placenta and fetal liver. After ~8-11 months of WD feeding, dams were similar in body weight but exhibited mild, systemic inflammation (elevated CRP and neutrophil count) and dyslipidemia (increased triglycerides and cholesterol) compared with dams fed a control diet. The maternal gut microbiome was mainly comprised of Lactobacillales and Clostridiales, with significantly decreased alpha diversity (P = 0.0163) in WD-fed dams but no community-wide differences (P = 0.26). At 0.9 gestation, mRNA expression of IL6 and TNF in maternal WD (mWD) exposed placentas trended higher, while increased triglycerides, expression of pro-inflammatory CCR2, and histological evidence for fibrosis were found in mWD-exposed fetal livers. In the mWD-exposed fetus, hepatic expression levels of miR-204-5p and miR-145-3p were significantly downregulated, whereas in mWD-exposed placentas, miR-182-5p and miR-183-5p were significantly decreased. Notably, miR-1285-3p expression in the liver and miR-183-5p in the placenta were significantly associated with inflammation and lipid synthesis pathway genes, respectively. Blautia and Ruminococcus were significantly associated with miR-122-5p in liver, while Coriobacteriaceae and Prevotellaceae were strongly associated with miR-1285-3p in the placenta; both miRNAs are implicated in pathways mediating postnatal growth and obesity. Our findings demonstrate that mWD shifts the maternal microbiome, lipid metabolism, and inflammation prior to obesity and are associated with epigenetic changes in the placenta and fetal liver. These changes may underlie inflammation, oxidative stress, and fibrosis patterns that drive NAFLD and metabolic disease risk in the next generation.