Animal evidence for the transgenerational development of diabetes mellitus

Maternal hyperglycemia and postnatal high-fat diet impair metabolic regulation and autophagy response in the liver of adult female rats

This study aimed to investigate the mechanisms by which the association between maternal hyperglycemia and postnatal high-fat diet (HFD) exposure compromises metabolic parameters and hepatic autophagy in adult female pups. For this, Sprague Dawley rats, female pups from nondiabetic (control = FC) or diabetic (FD) mothers, were fed a standard diet (SD) or HFD from weaning until adulthood (n minimum = 5 rats/group): FC/SD, FC/HFD, FD/SD, and FD/HFD. In adulthood, these rats were tested with the oral glucose tolerance test, euthanized, and serum biochemistry parameters were analyzed. Liver samples were collected to evaluate cytokines, redox status, and protein expression autophagy and apoptosis markers. Histomorphometric analyses and an assessment of lipofuscin accumulation were also performed to reflect incomplete autolysosomal digestion. The FC/HFD, FD/SD, and FD/HFD groups showed glucose intolerance and an increased number of hepatocytes. Furthermore, FD/SD and FD/HFD rats showed hyperlipidemia and insulin resistance. Adaptations in hepatic redox pathways were observed in the FD/SD group with increased antioxidant defense marker activity. The FD/SD group also exhibited increased autophagy protein expression, such as p-AMPK, LC3-II/LC3-I, and p62/SQSTM1, lipofuscin accumulation, and caspase-3 activation. After exposure to HFD, the adult female pups of diabetic rats had a reduced p-AMPK and LC3-II/LC3-I ratio, the presence of steatosis, oxidative stress, and inflammation. The reduction of autophagy, stimulated by HFD, may be of vital importance for the susceptibility to metabolic dysfunction-associated fatty liver disease induced by maternal diabetes.

Systemic/Immune-Modulation of Olea europaea Leaf Extract in Fetuses of Alloxan-Induced T1 Diabetic Rats

Maternal glucose is the principal macronutrient that sustains fetal growth. Prolonged exposure of the fetus to hyperglycemia from the early stages of pregnancy accelerates the maturation of the stimulus-secretion coupling mechanism in β cell autoimmunity, which leads to early hyperinsulinemia in type 1 diabetes mellitus (T1DM). Nowadays, diabetes mellitus (DM) is the most common medical complication of pregnancy, and among young women, the prevalence of overt diabetes and undiagnosed hyperglycemia is rising. Even though conventional medication is effective in treating DM, it is expensive and has harmful side effects. Herbal medicine will thus incorporate alternative therapy and be more effective and less toxic. Due to their bioactive components, olive leaves (Olea europaea) are frequently used medicinally; however, little is known about how this plant affects the immune system when it comes to diabetes. The current study used a pregnant mother rat model of alloxan-induced T1DM to examine the antidiabetic properties and embryonic safety of olive leaves. Forty adult female Sprague Dawley rats were split up into four groups as follows: nondiabetic, diabetic, olive, and diabetic-olive groups. All the mother rats were sacrificed on the 20th day of pregnancy, and fetuses were collected for further investigations. In diabetic pregnant mothers, fetuses had systemic modulation-negative effects. These effects were significantly reversed when the diabetic groups were supplemented with extracts from olive leaves. The findings showed that the olive leaf extract inhibits the diabetogenic effect mediated by alloxan with effective and protective systemic immunomodulation during embryonic development.

Hormonal regulation in diabetes: Special emphasis on sex hormones and metabolic traits

Diabetes constitutes a significant global public health challenge that is rapidly reaching epidemic proportions. Among the non-communicable diseases, the incidence of diabetes is rising at an alarming rate. The International Diabetes Federation has documented a 9.09% prevalence of diabetes among individuals aged between 20 and 79 years. The interplay of gonadal hormones and gender differences is critical in regulating insulin sensitivity and glucose tolerance, and this dynamic is particularly crucial because of the escalating incidence of diabetes. Variations in insulin sensitivity are observed across genders, levels of adiposity, and age groups. Both estrogen and testosterone are seen to influence glucose metabolism and insulin sensitivity. This chapter surveys the present knowledge of sex differences, sex hormones, and chromosomes on insulin imbalance and diabetes development. It further highlights the influence of metabolic traits in diabetes and changes in sex hormones during diabetic pregnancy. Notably, even stressful lifestyles have been acknowledged to induce hormonal imbalances. Furthermore, it discusses the potential of hormonal therapy to help stabilize sex hormones in diabetic individuals and focuses on the most recent research investigating the correlation between sex hormones and diabetes.

The Effects of a Western Diet vs. a High-Fiber Unprocessed Diet on Health Outcomes in Mice Offspring

Diet influences critical periods of growth, including gestation and early development. We hypothesized that a maternal/early life diet reflecting unprocessed dietary components would positively affect offspring metabolic and anthropometric parameters. Using 9 C57BL-6 dams, we simulated exposure to a Western diet, a high-fiber unprocessed diet (HFUD), or a control diet. The dams consumed their respective diets (Western [n = 3], HFUD [n = 3], and control [n = 3]) through 3 weeks of pregnancy and 3 weeks of weaning; their offspring consumed the diet of their mother for 4.5 weeks post weaning. Measurements included dual X-ray absorptiometry (DEXA) scans, feed consumption, body weight, blood glucose, and insulin and glycated hemoglobin (HbA1c) in the offspring. Statistical analyses included one-way ANOVA with Tukey's post hoc analysis. The offspring DEXA measures at 5 and 7.5 weeks post parturition revealed higher lean body mass development in the HFUD and control diet offspring compared to the Western diet offspring. An analysis indicated that blood glucose (p = 0.001) and HbA1c concentrations (p = 0.002) were lower among the HFUD offspring compared to the Western and control offspring. The results demonstrate that diet during gestation and early life consistent with traditional diet patterns may influence hyperglycemia and adiposity in offspring.

Supplementation With Fish Oil in Pregnancy Reduces Gastroenteritis in Early Childhood

BACKGROUND

We hypothesized that insufficient intake of fish oil-derived omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) during pregnancy is a contributing factor to gastroenteritis in early childhood. We examined the effect of n-3 LCPUFA supplementation on gastroenteritis symptoms in the offspring's first 3 years of life.

METHODS

This was a double-blinded, randomized controlled trial whereby 736 mothers were administered n-3 LCPUFA or control from pregnancy week 24 until 1 week after birth. We measured the number of days with gastroenteritis, number of episodes with gastroenteritis, and the risk of having a gastroenteritis episode in the first 3 years of life.

RESULTS

A median reduction of 2.5 days with gastroenteritis (P = .018) was shown, corresponding to a 14% reduction in the n-3 LCPUFA group compared with controls in the first 3 years of life (P = .037). A reduction in the number of gastroenteritis episodes (P = .027) and a reduced risk of having an episode (hazard ratio, 0.80 [95% confidence interval, .66-.97]; P = .023) were also shown.

CONCLUSIONS

Fish oil supplementation from the 24th week of pregnancy led to a reduction in the number of days and episodes with gastroenteritis symptoms in the first 3 years of life. The findings suggest n-3 LCPUFA supplementation as a preventive measure against gastrointestinal infections in early childhood.

CLINICAL TRIALS REGISTRATION

NCT00798226.

Protein restriction during lactation causes transgenerational metabolic dysfunction in adult rat offspring

Introduction

Protein restriction during lactation can induce metabolic dysfunctions and has a huge impact on the offspring's phenotype later in its life. We tested whether the effects of a maternal low-protein diet (LP) in rats can be transmitted to the F2 generation and increase their vulnerability to dietary insults in adulthood.

Methods

Female Wistar rats (F0) were fed either a low-protein diet (LP; 4% protein) during the first 2 weeks of lactation or a normal-protein diet (NP; 23% protein). The female offspring (F1 generation) were maintained on a standard diet throughout the experiment. Once adulthood was reached, female F1 offspring from both groups (i.e., NP-F1 and LP-F1) were bred to proven males, outside the experiment, to produce the F2 generation. Male F2 offspring from both groups (NP-F2 and LP-F2 groups) received a standard diet until 60 days old, at which point they received either a normal fat (NF; 4.5% fat) or a high fat diet (HF; 35% fat) for 30 days.

Results

At 90 days old, LPNF-F2 offspring had increased lipogenesis and fasting insulinemia compared to NPNF-F2, without alteration in insulin sensitivity. HF diet caused increased gluconeogenesis and displayed glucose intolerance in LPHF-F2 offspring compared to LPNF-F2 offspring. Additionally, the HF diet led to damage to lipid metabolism (such as steatosis grade 3), higher body weight, fat pad stores, and hepatic lipid content.

Discussion

We concluded that an F0 maternal protein restricted diet during lactation can induce a transgenerational effect on glucose and liver metabolism in the F2 generation, making the offspring's liver more vulnerable to nutritional injury later in life.

Transgenerational effects of zinc, selenium and chromium supplementation on glucose homeostasis in female offspring of gestational diabetes rats

Clinical studies have demonstrated that maternal gestational diabetes mellitus (GDM) increases the offspring's risk of developing glucose intolerance. Our previous study reported that co-supplementation with zinc, selenium, and chromium improved insulin resistance in diet-induced GDM rats. Here, Transgenerational effects of supplementation with zinc (10 mg/kg.bw), selenium (20 μg/kg.bw), and chromium (20 μg/kg.bw) in F1 female offspring of both zinc, selenium and chromium (ZnSeCr)-treated, and untreated GDM rats daily by gavage from weaning to the postpartum were investigated in the present study. Glucose homeostasis in the F1 female offspring of GDM at different stages were evaluated. Maternal GDM did increase the birth mass of newborn F1 female offspring, as well as the serum glucose and insulin levels. Zinc, selenium and chromium supplementation attenuated the GDM-induced mass gain, increased serum glucose and insulin levels in the female neonates. The high fat and sucrose (HFS) diet-fed GDM-F1 offspring developed GDM, with glucose intolerance, hyperglycemia and insulin resistance during pregnancy. Moreover, endoplasmic reticulum (ER) stress-related protein levels were increased and the activation of insulin signaling pathways were reduced in the liver of HFS-fed GDM-F1 offspring. Whereas glucose homeostasis in parallel with insulin sensitivity was normalized in the female offspring of GDM by supplementation both F0 dams and F1 offspring with zinc, selenium and chromium, not in those either F0 or F1 elements supplemented offspring. Therefore, we speculate that zinc, selenium and chromium supplementation may have a potential beneficial transgenerational effect on the glucose homeostasis in the female offspring of GDM.

Crucial nuances in understanding (mis)associations between the neonatal microbiome and Cesarean delivery

As rates of Cesarean delivery and common non-communicable disorders (NCDs), such as obesity, metabolic disease, and atopy/asthma, have concomitantly increased in recent decades, investigators have attempted to discern a causal link. One line of research has led to a hypothesis that Cesarean birth disrupts the presumed normal process of colonization of the neonatal microbiome with vaginal microbes, yielding NCDs later in life. However, a direct link between a disrupted microbiota transfer at time of delivery and acute and/or chronic illness in infants born via Cesarean has not been causally established. Microbiota seeding from maternal vaginal or stool sources has been preliminarily evaluated as an intervention designed to compensate for the lack of (or limited) exposure to such sources among Cesarean-delivered neonates. However, to date, clinical trials have yet to show a clear health benefit with neonatal 'vaginal seeding' practices. Until the long-term effects of these microbiome alterations can be fully determined, it is paramount to conduct parallel meaningful and mechanistic-minded interrogations of the impact of clinically modifiable maternal, nutritional, or environmental exposure on the functional microbiome over the duration of pregnancy and lactation to determine their role in the mitigation of childhood and adult NCDs.

Trans- and Multigenerational Maternal Social Isolation Stress Programs the Blood Plasma Metabolome in the F3 Generation

Metabolic risk factors are among the most common causes of noncommunicable diseases, and stress critically contributes to metabolic risk. In particular, social isolation during pregnancy may represent a salient stressor that affects offspring metabolic health, with potentially adverse consequences for future generations. Here, we used proton nuclear magnetic resonance (¹H NMR) spectroscopy to analyze the blood plasma metabolomes of the third filial (F3) generation of rats born to lineages that experienced either transgenerational or multigenerational maternal social isolation stress. We show that maternal social isolation induces distinct and robust metabolic profiles in the blood plasma of adult F3 offspring, which are characterized by critical switches in energy metabolism, such as upregulated formate and creatine phosphate metabolisms and downregulated glucose metabolism. Both trans- and multigenerational stress altered plasma metabolomic profiles in adult offspring when compared to controls. Social isolation stress increasingly affected pathways involved in energy metabolism and protein biosynthesis, particularly in branched-chain amino acid synthesis, the tricarboxylic acid cycle (lactate, citrate), muscle performance (alanine, creatine phosphate), and immunoregulation (serine, threonine). Levels of creatine phosphate, leucine, and isoleucine were associated with changes in anxiety-like behaviours in open field exploration. The findings reveal the metabolic underpinnings of epigenetically heritable diseases and suggest that even remote maternal social stress may become a risk factor for metabolic diseases, such as diabetes, and adverse mental health outcomes. Metabolomic signatures of transgenerational stress may aid in the risk prediction and early diagnosis of non-communicable diseases in precision medicine approaches.

Short Communication: Maternal undernutrition during peri-conceptional period affects whole genome ovine muscle methylation in adult offspring

Experimental and epidemiological studies suggest that maternal nutritional status during early pregnancy, including the period around the time of conception, may induce long-lasting epigenetic changes in the offspring. However, this remains largely unexplored in livestock. Therefore, the objective of this study was to evaluate if modification of the maternal diet of sheep (CTR: control; UND: 50% undernutrition) during the peri-conceptional period (42 days in total: -14/+28 from mating), would impact CpG methylation in muscle tissue (Longissimus dorsi) of adult offspring (11.5 months old). Reduced Representation Bisulfite Sequencing (RRBS), identified 262 (Edge-R, FDR<0.05) and 686 (Logistic Regression, FDR <0.001) differentially methylated regions (DMRs) between the UND and CTR groups. Gene ontology (GO) analysis identified genes related to development, functions of the muscular system and steroid hormone receptor activity within the DMRs. The data reported here show that nutritional stress during early pregnancy leads to epigenetic modifications in the muscle of the resulting offspring, with possible implications for cardiac dysfunction, muscle physiology and meat production.

TiO2 NPs induce the reproductive toxicity in mice with gestational diabetes mellitus through the effects on the endoplasmic reticulum stress signaling pathway

The effect of one of the most widely studied nanomaterials at present, TiO₂ nanoparticles (NPs), on pregnancy-related diseases is not clear. In this study, the adverse effects of TiO₂ NPs on mice with gestational diabetes mellitus (GDM) and their possible mechanism were investigated. GDM mice were orally administered 0, 10, 50 and 250 mg/kg TiO₂ NPs for 14 days. GDM reduced the weight of pregnant mice, destroyed the placental structure and caused abnormal fetal development. After exposure to increasing doses of TiO₂ NPs, blood glucose levels increased significantly and body weight further decreased in GDM mice. The accumulation of the Ti content was detected in the placenta and fetus, which may further damage the placental structure in GDM mice, thereby exacerbating abnormal fetal development. In addition, the MDA and SOD activities were obviously increased, and the expression of genes associated with endoplasmic reticulum stress (ERS) (PERK, eIF2α, AFT4, IRE1α, and XBP1s) and apoptosis (CHOP, JNK, Bax/Bcl-2, Caspase-12, Caspase-9, and Caspase-3) were also obviously increased in the placenta, which reflected the possible activation of apoptosis. It could be speculated that the reproductive toxicity of TiO₂ NPs in GDM mice triggered oxidative stress that subsequently activated ERS pathways to induce cell apoptosis.

Exposure to maternal hyperglycemia and high-fat diet consumption after weaning in rats: repercussions on periovarian adipose tissue

Clinical and epidemiological studies show that maternal hyperglycemia can change the programming of offspring leading to transgenerational effects. These changes may be related to environmental factors, such as high-fat diet (HFD) consumption, and contribute to the comorbidity onset at the adulthood of the offspring. The objective of this study was to evaluate the hyperglycemic intrauterine environment, associated or not with an HFD administered from weaning to adult life on the periovarian adipose tissue of rat offspring Maternal diabetes was chemically induced by Streptozotocin. Female offsprings were randomly distributed into four experimental groups (n = 5 animals/group): Female offspring from control or diabetic mothers and fed an HFD or standard diet. HFD was prepared with lard enrichment and given from weaning to adulthood. On day 120 of life, the rats were anesthetized and sacrificed to obtain adipose tissue samples. Then, the hyperglycemic intrauterine environment and HFD fed after weaning caused a higher body weight, total fat, and periovarian fat in adult offspring, which could compromise the future reproductive function of these females. These rats showed higher adiposity index and adipocyte area, contributing to hypertrophied adipose tissue. Therefore, maternal diabetes itself causes intergenerational changes and, in association with the HFD consumption after weaning, exacerbated the changes in the adipose tissue of adult female offspring.

Effects of snack intake during pregnancy and lactation on reproductive outcome in mild hyperglycemic rats

Metabolic disorders, like diabetes, as well as maternal diet, alter nutrient availability in utero, inducing adaptations in the offspring. Whether the effects of maternal hyperglycemia are modulated by diet, however, has yet to be explored. In the current study, we examined this issue by giving females rats, treated neonatally with STZ to induce mild hyperglycemia, and control littermates either ad libitum access to standard chow (Control n = 17; STZ n = 16) or standard chow and snacks (Control-snack n = 18; STZ-snack n = 19) (potato chips and a red fruit-flavored sucrose syrup solution 1.5%) throughout pregnancy and lactation. We hypothesized that the maternal glucose intolerance typically seen in female rats treated neonatally with STZ would be exacerbated by snack intake, and that the combination of snack intake and STZ treatment would lead to alterations in maternal behavior and offspring development. Maternal body weight and food intake were measured daily through pregnancy and lactation and litter weight throughout lactation. At birth, litter size, offspring weight, body length, and anogenital distance were obtained and offspring were classified according to their weight. Measures of nursing and retrieval behavior, as well as exploration in the open field and the elevated plus-maze were also recorded. As predicted, snack intake tended to aggravate the glucose intolerance of STZ-treated rats during pregnancy. Both Control and STZ-treated females that had access to snacks ate more calories and fat, but less carbohydrate and protein than females having access to chow alone. Overall, STZ-treated dams gave birth to fewer pups. Chow-fed STZ females gave birth to a greater proportion of large for pregnancy age pups, whereas dams in the Control-snack group gave birth to a greater proportion of small pups. The birth weight classification of pups born to STZ-snack rats, however, resembled that of the Control chow-fed females. Although all litters gained weight during lactation, litters from snack-fed dams gained less weight regardless of maternal hyperglycemia and did not show catch-up growth by weaning. Overall, STZ rats spent more time nest building, whereas the average inter milk ejection interval was higher in snack-fed females. STZ-snack dams retrieved the complete litter faster than dams in the other groups. Together, these data suggest that when mild hyperglycemic females are given access to snacks throughout pregnancy and lactation their intake is similar to that of Control females given snack access. The combination of hyperglycemia and snack access tended to decrease glucose tolerance in pregnancy, and normalized birth weight classification, but produced few other effects that were not seen as a function of snack intake or hyperglycemia alone. Since birth weight is a strong predictor of health issues, future studies will further investigate offspring behavioral and metabolic outcomes later in life.

Adiponectin agonist treatment in diabetic pregnant rats

Gestational diabetes mellitus (GDM) reduces maternal adiponectin and docosahexaenoic acid (DHA) materno-fetal transfer, which may have negative consequences for the offspring. Our aim was to evaluate the effects of the administration of a novel adiponectin agonist (AdipoRon) to GDM rats on the long-term consequences in glycaemia and fatty acids (FA) profile in the offspring. Pregnant rats were randomized to three groups: GDM rats (GDM, n = 8), GDM rats treated with AdipoRon (GDM + ADI, n = 9), and control rats (n = 10). Diabetes was induced with streptozotocin (50 mg/kg) on day 12 of gestation. GDM+ADI received 50 mg/kg/day AdipoRon from day 14 until delivery. Glycaemia and FA profile were determined in mothers and adult offspring (12 weeks old). AdipoRon tended to reduce fasting glucose in diabetic mothers. Diabetic rats presented the foetus with intrauterine growth restriction and higher adiposity, which tried to be counteracted by AdipoRon. In the adult offspring, both GDM + ADI and control animals showed better glucose recovery after oral glucose overload with respect to GDM. DHA in offspring plasma was significantly reduced in both GDM and GDM + ADI compared to controls (P = 0.043). Nevertheless, n-6/n-3 polyunsaturated FA (PUFA) ratio improved in plasma of GDM + ADI adult offspring (GDM: 14.83 ± 0.85a%; GDM + ADI: 11.49 ± 0.58b%; control: 10.03 ± 1.22b%, P = 0.034). Inflammatory markers and oxidative stress were reduced in the adult offspring of AdipoRon-treated mothers. In conclusion, AdipoRon administration to pregnant diabetic rats improved glycaemia in the mothers and long-term glucose tolerance in the offspring. In addition, it tended to reduce excessive foetal fat accumulation and improved n-6/n-3 PUFA ratio significantly in offspring at the adult state.

Effects of Gestational Diabetes in Cognitive Behavior, Oxidative Stress and Metabolism on the Second-Generation Off-Spring of Rats

Gestational diabetes (GD) has a negative impact on neurodevelopment, resulting in cognitive and neurological deficiencies. Oxidative stress (OS) has been reported in the brain of the first-generation offspring of GD rats. OS has been strongly associated with neurodegenerative diseases. In this work, we determined the effect of GD on the cognitive behavior, oxidative stress and metabolism of second-generation offspring. GD was induced with streptozotocin (STZ) in pregnant rats to obtain first-generation offspring (F1), next female F1 rats were mated with control males to obtain second-generation offspring (F2). Two and six-month-old F2 males and females were employed. Anxious-type behavior, spatial learning and spatial working memory were evaluated. In cerebral cortex and hippocampus, the oxidative stress and serum biochemical parameters were measured. Male F2 GD offspring presented the highest level of anxiety-type behavior, whilst females had the lowest level of anxiety-type behavior at juvenile age. In short-term memory, adult females presented deficiencies. The offspring F2 GD females presented modifications in oxidative stress biomarkers in the cerebral cortex as lipid-peroxidation, oxidized glutathione and catalase activity. We also observed metabolic disturbances, particularly in the lipid and insulin levels of male and female F2 GD offspring. Our results suggest a transgenerational effect of GD on metabolism, anxiety-like behavior, and spatial working memory.

Maternal blood glucose level and offspring glucose-insulin homeostasis: what is the role of offspring adiposity?

AIMS/HYPOTHESIS

The aim of this work was to investigate the association of maternal HbA_1c during mid-pregnancy with biomarkers of glucose-insulin homeostasis during early childhood (4-7 years of age) and to assess whether and how offspring adiposity at birth and at age 4-7 years mediates this relationship among 345 mother-child pairs in the Healthy Start Study.

METHODS

The exposure was maternal HbA_1c (mmol/mol) measured at 20-34 gestational weeks and categorised into tertiles. The outcomes were offspring fasting glucose, 1/insulin, HOMA2-IR, and HOMA2-B at age 4-7 years. The mediators were per cent fat mass (%FM) at birth, %FM at age 4-7 years, and the sum of the two as a metric of cumulative adiposity. Mediation analyses were conducted via a counterfactual-based approach. All models accounted for maternal race/ethnicity, offspring age and sex.

RESULTS

There was a significant total effect of maternal HbA_1c on offspring glucose and 1/insulin. Specifically, we observed a positive trend across tertiles of HbA_1c and offspring glucose (p trend <0.001), and an inverse trend across tertiles of HbA_1c and offspring 1/insulin (p trend = 0.04). For instance, compared with offspring of women in the lowest tertile of HbA_1c, those whose mothers were in the second and third tertiles had 0.04 mmol/l (95% CI -0.05, 0.13) and 0.17 mmol/l (95% CI 0.08, 0.26) higher fasting glucose concentrations at age 4-7 years, respectively. Adjustment for pre-pregnancy BMI did not appreciably change the results. We found no evidence of mediation by offspring adiposity at any life stage.

CONCLUSIONS/INTERPRETATION

Offspring of women with higher HbA_1c during pregnancy had higher fasting glucose and lower insulin sensitivity by early childhood. These relationships were largely unaffected by the child's own adiposity. Graphical abstract.

Imprinted Genes Impact Upon Beta Cell Function in the Current (and Potentially Next) Generation

Beta cell failure lies at the centre of the aetiology and pathogenesis of type 2 diabetes and the epigenetic control of the expression of critical beta cell genes appears to play a major role in this decline. One such group of epigenetically-controlled genes, termed 'imprinted' genes, are characterised by transgenerational monoallelic expression due to differential allelic DNA methylation and play key functional roles within beta cells. Here, we review the evidence for this functional importance of imprinted genes in beta cells as well as their nutritional regulation by the diet and their altered methylation and/or expression in rodent models of diabetes and in type 2 diabetic islets. We also discuss imprinted genes in the context of the next generation, where dietary overnutrition in the parents can lead to their deregulation in the offspring, alongside beta cell dysfunction and defective glucose handling. Both the modulation of imprinted gene expression and the likelihood of developing type 2 diabetes in adulthood are susceptible to the impact of nutritional status in early life. Imprinted loci, therefore, represent an excellent opportunity with which to assess epigenomic changes in beta cells due to the diet in both the current and next generation.

The Transgenerational Transmission of the Paternal Type 2 Diabetes-Induced Subfertility Phenotype

Diabetes is a chronic metabolic disorder characterized by hyperglycemia and associated with many health complications due to the long-term damage and dysfunction of various organs. A consequential complication of diabetes in men is reproductive dysfunction, reduced fertility, and poor reproductive outcomes. However, the molecular mechanisms responsible for diabetic environment-induced sperm damage and overall decreased reproductive outcomes are not fully established. We evaluated the effects of type 2 diabetes exposure on the reproductive system and the reproductive outcomes of males and their male offspring, using a mouse model. We demonstrate that paternal exposure to type 2 diabetes mediates intergenerational and transgenerational effects on the reproductive health of the offspring, especially on sperm quality, and on metabolic characteristics. Given the transgenerational impairment of reproductive and metabolic parameters through two generations, these changes likely take the form of inherited epigenetic marks through the germline. Our results emphasize the importance of improving metabolic health not only in women of reproductive age, but also in potential fathers, in order to reduce the negative impacts of diabetes on subsequent generations.

Associations of Dietary Bioactive Compounds with Maternal Adiposity and Inflammation in Gestational Diabetes: An Update on Observational and Clinical Studies

Gestational diabetes mellitus (GDM) is a common complication of pregnancy that adversely affects maternal and offspring health. Maternal obesity, oxidative stress, and inflammation have been implicated in GDM. In non-pregnant adults, intakes of dietary bioactive compounds inversely associate with insulin resistance and inflammation. However, associations of dietary bioactive compounds with biomarkers of adiposity, antioxidant vitamin and mineral status, oxidative stress, and inflammation in GDM have not been fully elucidated. We addressed this gap by conducting a semi-quantitative review of observational studies and randomized controlled trials published between 2010 and 2020 and retrieved from Google Scholar, Medline, and PubMed. Our analysis revealed that women with GDM are more likely to consume a pro-inflammatory diet before pregnancy and tend to consume fewer antioxidant vitamins and minerals during pregnancy than healthy pregnant women. Women with GDM also have lower blood levels of vitamins A, C, and D and certain adipokines. Several dietary bioactive compounds were noted to improve antioxidant status and biomarkers of inflammation. The Dietary Approaches to Stop Hypertension (DASH) diet and soybean oligosaccharides increased antioxidant enzyme levels. Supplementing n-3 fatty acids, probiotics, synbiotics, and trace elements increased antioxidant enzymes and reduced hs-CRP and MDA. Improvements in inflammation by vitamin D may be contingent upon co-supplementation with other dietary bioactive compounds.

Could the E/A ratio be included in the cardiological evaluation of the offspring of diabetic mothers? A case-control study in South Sardinia

INTRODUCTION

Diabetes mellitus (DM) is a chronic disease widespread in the world. Sardinia represents, together with Finland, the region with the highest incidence of type 1 DM (DM1), as well as a high prevalence of gestational DM (GDM). Despite the improvement in obstetric surveillance, perinatal and long-term adverse outcomes are still frequent in the offspring of diabetic mothers. During gestations complicated by DM, fetal heart is one of the most affected organ potentially undergoing structural heart defects or several degrees of fetal myocardium hypertrophy and impaired cardiac function.

AIM

The aim of our study was to evaluate, through echocardiographic examination, cardiac features and performance in a South Sardinian population of newborns of diabetic mothers comparing them to a group of control subjects.

CONCLUSIONS

In our sample, the E/A ratio resulted a significant marker of early diastolic dysfunction in asymptomatic neonates born by diabetic mothers, even if such result should be confirmed on larger samples.

Multigenerational effects of cadmium on the lifespan and fertility of Drosophila melanogaster

Although the damage and tolerance mechanisms of Cd stress are known, the data on genetic risk are limited. The aim of this study was to assess the chronic toxicity of Cd, genetic responses, and multigenerational effects in five generations of Drosophila melanogaster. For each generation, lifespan and fertility were statistically analysed and the expression of apoptosis- (p53 and caspase-3) and epigenesis-related (dDnmt2 and dMBD2/3) genes was examined. Lifespan and fertility significantly declined under Cd stress and these effects were maintained for two generations and one generation, respectively, when Cd stress was removed. The expression of p53 and caspase-3 was significantly up-regulated after exposure, suggesting that apoptosis contributes to the resistance mechanism. Their altered expression was retained for two generations. Furthermore, high expression of dDnmt2 and dMBD2/3 accompanied Cd exposure, which was passed on to three generations, suggesting that genetic modifications in apoptosis-related genes are carried to the offspring through epigenetic regulation.

Gestational Diabetes Triggers Oxidative Stress in Hippocampus and Cerebral Cortex and Cognitive Behavior Modifications in Rat Offspring: Age- and Sex-Dependent Effects

Gestational diabetes (GD) has been linked with an increased risk of developing metabolic disorders and behavioral abnormalities in the offspring. Oxidative stress is strongly associated with neurodegeneration and cognitive disruption. In the offspring brains in a GD experimental rat model, increased oxidative stress in the prenatal and postnatal stages was reported. However, long-term alterations to offspring behavior and oxidative stress, caused by changes in the cerebral cortex and hippocampus, remain unclear. In this study, we evaluated the effect of GD on young and adult male and female rat offspring in metabolic parameters, cognitive behavior, and oxidative stress. GD was induced using streptozotocin in dams. Next, the offspring were evaluated at two and six months of age. Anxiety-like behavior was evaluated using the elevated plus maze and open field maze; spatial learning and short-term memory were evaluated using the Morris water maze and radial maze, respectively. We determined oxidative stress biomarkers (reactive oxygen species (ROS), lipid peroxidation and glutathione status) and antioxidant enzymes (superoxide dismutase and catalase) in the brain of offspring. We observed that male GD offspring showed a reduced level of anxiety at both ages as they spent less time in the closed arms of the elevated plus maze at adult age ((P = 0.019, d = 1.083 ( size effect)) and spent more time in the open area of an open field (P = 0.0412, d = 0.743) when young and adult age (P = 0.018, d = 0.65). Adult female GD offspring showed a reduced level of anxiety (P = 0.036; d = 0.966), and young female GD offspring showed a deficiency in spatial learning (P = 0.0291 vs. control, d = 3.207). Adult male GD offspring showed a deficiency in short-term memory (P = 0.017, d = 1.795). We found an increase in ROS and lipid peroxidation, a disruption in the glutathione status, and decreased activity of catalase and superoxide dismutase (P < 0.05 vs. control, d > 1.0), in the cerebral cortex and hippocampus of male and female GD offspring. GD altered metabolism; male offspring of both ages and adult females showed a high level of triglycerides and a lower level of high-density lipoprotein-cholesterol (P < 0.05 vs. control, d > 1.0). Young and adult female offspring displayed higher insulin levels (P < 0.05, d > 1.0). These results suggest that gestational diabetes modifies oxidative stress and cognitive behavior in an age- and sex-dependent manner.

Early-Life Arsenic Exposure, Nutritional Status, and Adult Diabetes Risk

PURPOSE OF REVIEW

In utero influences, including nutrition and environmental chemicals, may induce long-term metabolic changes and increase diabetes risk in adulthood. This review evaluates the experimental and epidemiological evidence on the association of early-life arsenic exposure on diabetes and diabetes-related outcomes, as well as the influence of maternal nutritional status on arsenic-related metabolic effects.

RECENT FINDINGS

Five studies in rodents have evaluated the role of in utero arsenic exposure with diabetes in the offspring. In four of the studies, elevated post-natal fasting glucose was observed when comparing in utero arsenic exposure with no exposure. Rodent offspring exposed to arsenic in utero also showed elevated insulin resistance in the 4 studies evaluating it as well as microRNA changes related to glycemic control in 2 studies. Birth cohorts of arsenic-exposed pregnant mothers in New Hampshire, Mexico, and Taiwan have shown that increased prenatal arsenic exposure is related to altered cord blood gene expression, microRNA, and DNA methylation profiles in diabetes-related pathways. Thus far, no epidemiologic studies have evaluated early-life arsenic exposure with diabetes risk. Supplementation trials have shown B vitamins can reduce blood arsenic levels in highly exposed, undernourished populations. Animal evidence supports that adequate B vitamin status can rescue early-life arsenic-induced diabetes risk, although human data is lacking. Experimental animal studies and human evidence on the association of in utero arsenic exposure with alterations in gene expression pathways related to diabetes in newborns, support the potential role of early-life arsenic exposure in diabetes development, possibly through increased insulin resistance. Given pervasive arsenic exposure and the challenges to eliminate arsenic from the environment, research is needed to evaluate prevention interventions, including the possibility of low-cost, low-risk nutritional interventions that can modify arsenic-related disease risk.

Developmental overnutrition and obesity and type 2 diabetes in offspring

Childhood obesity has reached pandemic proportions, and youth-onset type 2 diabetes is following suit. This review summarises the literature on the influence of developmental overnutrition, resulting from maternal diabetes, obesity, maternal dietary intake during pregnancy, excess gestational weight gain, and infant feeding practices, on the aetiology of obesity and type 2 diabetes risk during childhood and adolescence. Key goals of this review are: (1) to summarise evidence to date on consequences of developmental overnutrition; (2) describe shared and distinct biological pathways that may link developmental overnutrition to childhood obesity and youth-onset type 2 diabetes; and (3) to translate current knowledge into clinical and public health strategies that not only target primary prevention in youth, but also encourage primordial prevention during the perinatal period, with the aim of breaking the intergenerational cycle of obesity and diabetes.

Gestational diabetes mellitus

Hyperglycaemia that develops during pregnancy and resolves after birth has been recognized for over 50 years, but uniform worldwide consensus is lacking about threshold hyperglycaemic levels that merit a diagnosis of 'gestational diabetes mellitus' (GDM) and thus treatment during pregnancy. GDM is currently the most common medical complication of pregnancy, and prevalence of undiagnosed hyperglycaemia and even overt diabetes in young women is increasing. Maternal overweight and obesity, later age at childbearing, previous history of GDM, family history of type 2 diabetes mellitus and ethnicity are major GDM risk factors. Diagnosis is usually performed using an oral glucose tolerance test (OGTT), although a non-fasting, glucose challenge test (GCT) is used in some parts of the world to screen women for those requiring a full OGTT. Dietary modification and increased physical activity are the primary treatments for GDM, but pharmacotherapy, usually insulin, is used when normoglycaemia is not achieved. Oral hypoglycaemic agents, principally metformin and glibenclamide (glyburide), are also used in some countries. Treatment improves immediate pregnancy outcomes, reducing excess fetal growth and adiposity and pregnancy-related hypertensive disorders. GDM increases the risk of long-term complications, including obesity, impaired glucose metabolism and cardiovascular disease, in both the mother and infant. Optimal management of mother and infant during long-term follow-up remains challenging, with very limited implementation of preventive strategies in most parts of the world.

Tertiary butylhydroquinone alleviates gestational diabetes mellitus in C57BL/KsJ-Lep db/+ mice by suppression of oxidative stress

Gestational diabetes mellitus (GDM) is a common disorder characterized by abnormal glucose metabolism during pregnancy, affecting 2% to 5% of pregnant women. Currently, clinical treatment for GDM is very limited. The present study was designed to investigate the effect and underlying molecular mechanism of tertiary butylhydroquinone (TBHQ) in a pregnant C57BL/KsJ-Lep db/+ (referred to as db+) GDM mouse model. The results showed that nonpregnant db/+ mice did not show a diabetic phenotype, and TBHQ had no effect on glucose and insulin tolerance in these mice. Moreover, in db/+ pregnant mice exhibiting typical diabetes symptoms, such as hyperglycemia and hypoinsulinemia, TBHQ could remarkably decrease the blood glucose level, increase insulin level, and improve glucose and insulin intolerance. The results also revealed that TBHQ could inhibit oxidative stress in pregnant db/+ mice. Furthermore, TBHQ greatly improved offspring survival rate, glucose metabolism, and insulin tolerance. In addition, TBHQ inhibited oxidative stress by reducing malondialdehyde (MDA) and reactive oxygen species (ROS) levels and increased superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities. Moreover, we found that TBHQ activated the nuclear factor erythroid 2-related factor 2 (Nrf2), thereby increasing the levels of Nrf2, and ultimately upregulating the expression of heme oxygenase 1 (NO-1) and superoxide dismutase 2 (SOD2). In conclusion, our findings demonstrated that TBHQ alleviated GDM via Nrf2 activation.

Exercise initiated during pregnancy in rats born growth restricted alters placental mTOR and nutrient transporter expression

KEY POINTS

Fetal growth is dependent on effective placental nutrient transportation, which is regulated by mammalian target of rapamycin (mTOR) complex 1 modulation of nutrient transporter expression. These transporters are dysregulated in pregnancies affected by uteroplacental insufficiency and maternal obesity. Nutrient transporters and mTOR were altered in placentae of mothers born growth restricted compared to normal birth weight dams, with maternal diet- and fetal sex-specific responses. Exercise initiated during pregnancy downregulated mTOR protein expression, despite an increase in mTOR activation in male associated placentae, and reduced nutrient transporter gene abundance, which was also dependent on maternal diet and fetal sex. Limited changes were characterized with exercise initiated before and continued throughout pregnancy in nutrient transporter and mTOR expression. Maternal exercise during pregnancy differentially regulated mTOR and nutrient transporters in a diet- and sex-specific manner, which likely aimed to improve late gestational placental growth and neonatal survival.

ABSTRACT

Adequate transplacental nutrient delivery is essential for fetoplacental development. Intrauterine growth restriction and maternal obesity independently alter placental nutrient transporter expression. Although exercise is beneficial for maternal health, limited studies have characterized how the timing of exercise initiation influences placental nutrient transport. Therefore, this study investigated the impact of maternal exercise on placental mechanistic target of rapamycin (mTOR) and nutrient transporter expression in growth restricted mothers and whether these outcomes were dependent on maternal diet or fetal sex. Uteroplacental insufficiency or sham surgery was induced on embryonic day (E) 18 in Wistar-Kyoto rats. F1 offspring were fed a chow or high-fat diet from weaning and at 16 weeks were randomly allocated to an exercise protocol: sedentary, exercised prior to and during pregnancy, or exercised during pregnancy only. Females were mated with normal males (20 weeks) and F2 placentae collected at E20. Exercise during pregnancy only, reduced mTOR protein expression in all groups and increased mTOR activation in male associated placentae. Exercise during pregnancy only, decreased the expression of amino acid transporters in a diet- and sex-specific manner. Maternal growth restriction altered mTOR and system A amino acid transporter expression in a sex- and diet-specific manner. These data highlight that maternal exercise initiated during pregnancy alters placental mTOR expression, which may directly regulate amino acid transporter expression, to a greater extent than exercise initiated prior to and continued during pregnancy, in a diet- and fetal sex-dependent manner. These findings highlight that the timing of exercise initiation is important for optimal placental function.

Mother or Father: Who Is in the Front Line? Mechanisms Underlying the Non-Genomic Transmission of Obesity/Diabetes via the Maternal or the Paternal Line

Extensive epidemiological and experimental evidence have shown that exposure to an adverse intrauterine environment as observed in offspring of pregnancies complicated by obesity or diabetes, can program susceptibility to metabolic, endocrine and cardiovascular disorders later in life. Although most studies have concentrated on the maternal environment, it is also becoming evident that paternal exposure to obesity or diabetes can result in the later development of metabolic disorders in the offspring. Such programmed effects might not be limited to the first directly exposed generation, but could be transmitted to subsequent generations. This suggests the existence of mechanisms by which metabolic changes in parental phenotype are transmissible to offspring. The mechanisms which underpin the transmission of the programmed effects across generations are still unclear. However, epigenetic regulation of transcription has emerged as a strong candidate for mediating the heritability of metabolic diseases. Here, we review the most relevant evidence from human and animal studies showing transmission of programming effects of obesity or diabetes across generations, and the current mechanisms underlying either maternal or paternal influences on the metabolic status of offspring.

Maternal exercise and growth restriction in rats alters placental angiogenic factors and blood space area in a sex-specific manner

Fetal growth and development are dependent on adequate placental nutrient transfer. The surface area of the placental villous network is a key determinant of nutrient exchange, which is regulated by vasculogenic and angiogenic factors. These factors are altered by intrauterine growth restriction (IUGR) and maternal obesity in both the first (F1) and second (F2) generations. We investigated the impact of endurance exercise in IUGR dams fed a High-fat diet on placental vasculogenesis and angiogenesis. Uteroplacental insufficiency (Restricted) or sham (Control) surgery was induced on embryonic day (E) 18 in Wistar-Kyoto rats. F1 offspring were fed a Chow or High-fat diet from weaning, and at 16 weeks were further allocated an exercise protocol; Sedentary, Exercised prior to and during pregnancy (Exercise), or Exercised during pregnancy only (PregEx). Females were mated (20 weeks) and F2 placentae collected at E20. Maternal Restriction, High-fat feeding and Exercise had a minimal impact on placental regulators of vasculogenesis and angiogenesis. However, Restriction increased placental labyrinth tissue area in Chow-fed dams. PregEx induced overt adaptations, including increased VEGFA and decreased PLGF protein expression, and reduced blood space area. These alterations were sex-dependent and associated with alterations in miRNA27a, a known regulator of VEGF translation. These data highlight that maternal exercise initiated during pregnancy (PregEx) causes alterations in placental vasculogenesis and angiogenesis in a sex-dependent manner, with minimal Restriction and maternal diet effects. However, further investigation is required to determine if these adaptations are beneficial or harmful for maternal and fetoplacental outcomes.

Small-for-pregnancy-age rats submitted to exercise: DNA damage in mothers and newborns, measured by the comet assay

BACKGROUND

Fetal impairment caused by a deleterious intrauterine environment may have long-term consequences, such as oxidative stress and genetic damage. Rats born as small-for-gestational-age (SPA) were submitted to exercise (swimming) before and during pregnancy. The animals exhibited glucose intolerance, reduced general adiposity, and increased maternal and offspring organ weight, showing the benefit of exercise for these rats. We hypothesised that regular exercise in SPA during gestation could prevent DNA damage in these animals and in their offspring, contributing to altered fetal programming of metabolism in the offspring. Severe diabetes was induced by streptozotocin treatment, to obtain SPA newborns. At adulthood, pregnant SPA rats were randomly distributed into two groups: exercised (SPAex - submitted to swimming program) or not-exercised (SPA - sedentary rats). Post-partum, blood was collected for analysis of DNA damage (comet assay) and oxidative stress. SPAex rats presented lower DNA damage levels, decreased lipid peroxidation, and a lower rate of newborns classified as large-for-pregnancy-age. DNA damage was also lower in SPAex newborns. We conclude that swimming applied to SPA pregnant rats contributes to decreased DNA damage and lipid peroxidation in the dams, and decreased DNA damage and macrosomia in their offspring.

Cell-Specific "Competition for Calories" Drives Asymmetric Nutrient-Energy Partitioning, Obesity, and Metabolic Diseases in Human and Non-human Animals

The mammalian body is a complex physiologic “ecosystem” in which cells compete for calories (i.e., nutrient-energy). Axiomatically, cell-types with competitive advantages acquire a greater number of consumed calories, and when possible, increase in size and/or number. Thus, it is logical and parsimonious to posit that obesity is the competitive advantages of fat-cells (adipocytes) driving a disproportionate acquisition and storage of nutrient-energy. Accordingly, we introduce two conceptual frameworks. Asymmetric Nutrient-Energy Partitioning describes the context-dependent, cell-specific competition for calories that determines the partitioning of nutrient-energy to oxidation, anabolism, and/or storage; and Effective Caloric Intake which describes the number of calories available to constrain energy-intake via the inhibition of the sensorimotor appetitive cells in the liver and brain that govern ingestive behaviors. Inherent in these frameworks is the independence and dissociation of the energetic demands of metabolism and the neuro-muscular pathways that initiate ingestive behaviors and energy intake. As we demonstrate, if the sensorimotor cells suffer relative caloric deprivation via asymmetric competition from other cell-types (e.g., skeletal muscle- or fat-cells), energy-intake is increased to compensate for both real and merely apparent deficits in energy-homeostasis (i.e., true and false signals, respectively). Thus, we posit that the chronic positive energy balance (i.e., over-nutrition) that leads to obesity and metabolic diseases is engendered by apparent deficits (i.e., false signals) driven by the asymmetric inter-cellular competition for calories and concomitant differential partitioning of nutrient-energy to storage. These frameworks, in concert with our previous theoretic work, the Maternal Resources Hypothesis, provide a parsimonious and rigorous explanation for the rapid rise in the global prevalence of increased body and fat mass, and associated metabolic dysfunctions in humans and other mammals inclusive of companion, domesticated, laboratory, and feral animals.

Association of Interleukin-10 Methylation Levels With Gestational Diabetes in a Taiwanese Population

Objective: Gestational diabetes mellitus (GDM) is defined as glucose intolerance with onset during pregnancy, which is also associated with future metabolic diseases in both patients and their offspring. The mechanisms underlying this condition remain largely unknown and may be partly related to epigenetics. The aim of this study was to compare the methylation levels of the cytokine interleukin-10 (IL-10) in pregnant women and their fetuses under both hyperglycemic and euglycemic environments, as those levels may be a clue to the epigenetic mechanisms underlying pathogenesis of GDM.

Methods: We analyzed the methylation levels of the IL-10 gene in maternal blood, cord blood, and placental tissue in both a GDM group (n = 8) and a control group (n = 24) using a LightCycler LC480 (Roche, Rotkreuz, Switzerland). IL-10 concentrations in maternal blood and THP-1 cells were measured by enzyme-linked immunosorbent assay (ELISA) using BD OptEIA Human IL-10 ELISA kits (BD Biosciences Pharmingen, San Diego, CA, United States).

Results: The maternal blood IL-10 methylation levels in the GDM group and the control group were 0.23 ± 0.04 and 0.26 ± 0.04, respectively (p = 0.03), but there were no significant differences between the levels of the two groups in the cord blood or placental tissue. Increased IL-10 plasma concentrations were discovered under hyperglycemic environments and were confirmed via the THP-1 cell line.

Conclusion: Hypomethylation of maternal blood and increased plasma IL-10 concentrations before birth were found in the GDM group.

Fetal pancreatic Langerhans islets size in pregnancies with metabolic disorders

Objective: Metabolic disorders are a pandemic and increasing health problem. Women of childbearing age may also be affected, thus an abnormal metabolism may interfere with pregnancy short- and long-term outcomes, harming both mother and child. In the context of an abnormal maternal and intrauterine metabolic milieu the development of fetal organs, including pancreas, may be affected. Aim: To investigate the effects of pregnancy metabolic disorders on the morphology of pancreatic Langerhans islets in human late-third trimester stillborn fetuses. Methods: Samples from fetal pancreas underwent a quantitative histological evaluation to detect differences between pregnancy with (cases, n = 9) or without (controls, n = 6) abnormal metabolism. Results: Results show that the islets size increases in fetuses from dysmetabolic pregnancies and that this increment is related to both beta-cell hyperplasia and hypertrophy. Moreover, according to pregnancy and fetal metabolic disorders, a threshold of abnormal size of the islets has been identified. Above this threshold the size of fetal pancreatic Langerhans islets should be considered excessively increased. Conclusion: The study suggests that an accurate fetal pancreas analysis supplies an important tool in stillborn fetus, to discover metabolic disturbances that should be kept in mind and managed in future pregnancies.

Comparative analysis of two different models of swimming applied to pregnant rats born small for pregnant age

The aim of this study was to compare two models of swimming applied to pregnant rats born small for pregnancy age (SPA). Diabetes was chemically induced in adult female rats to develop an inadequate intrauterine environment, leading to birth of a SPA offspring. In adulthood, the female SPA rats were mated and submitted to different swimming programs. The exercise program 1 (Ex1) consisted of swimming for 15 minutes, followed by 15 minutes of rest and another 15 minutes of swimming, 3 days a week before and during pregnancy. Another program (Ex2) was applied during 60 minutes uninterrupted a day, 6 days/week during pregnancy. The pregnant rats presented no interference on body weight and glycemia. The rats submitted to Ex2 model showed decreased insulin and blood glucose levels by oral glucose tolerance test, and reduction in area under curve values. The offspring from dams submitted to both exercise protocols presented an increased rate of newborns SPA. However, the offspring from Ex2 dams showed percentage twice higher of newborns SPA than Ex1 offspring. Our data suggests that continuous exercise of 60 min/day ameliorated the enhanced peripheral insulin sensitivity in growth-restricted females. However, this protocol employed at pregnancy leads to intrauterine growth restriction.

The role of polycarbonate monomer bisphenol-A in insulin resistance

Bisphenol A (BPA) is a synthetic unit of polycarbonate polymers and epoxy resins, the types of plastics that could be found in essentially every human population and incorporated into almost every aspect of the modern human society. BPA polymers appear in a wide range of products, from liquid storages (plastic bottles, can and glass linings, water pipes and tanks) and food storages (plastics wraps and containers), to medical and dental devices. BPA polymers could be hydrolyzed spontaneously or in a photo- or temperature-catalyzed process, providing widespread environmental distribution and chronic exposure to the BPA monomer in contemporary human populations. Bisphenol A is also a xenoestrogen, an endocrine-disrupting chemical (EDC) that interferes with the endocrine system mimicking the effects of an estrogen and could potentially keep our endocrine system in a constant perturbation that parallels endocrine disruption arising during pregnancy, such as insulin resistance (IR). Gestational insulin resistance represents a natural biological phenomenon of higher insulin resistance in peripheral tissues of the pregnant females, when nutrients are increasingly being directed to the embryo instead of being stored in peripheral tissues. Gestational diabetes mellitus may appear in healthy non-diabetic females, due to gestational insulin resistance that leads to increased blood sugar levels and hyperinsulinemia (increased insulin production from the pancreatic beta cells). The hypothesis states that unnoticed and constant exposure to this environmental chemical might potentially lead to the formation of chronic low-level endocrine disruptive state that resembles gestational insulin resistance, which might contribute to the development of diabetes. The increasing body of evidence supports the major premises of this hypothesis, as exemplified by the numerous publications examining the association of BPA and insulin resistance, both epidemiological and mechanistic. However, to what extent BPA might contribute to the development of diabetes in the modern societies still remains unknown. In this review, I discuss the chemical properties of BPA and the sources of BPA contamination found in the environment and in human tissues. I provide an overview of mechanisms for the proposed role of bisphenol A in insulin resistance and diabetes, as well as other related diseases, such as cardiovascular diseases. I describe the transmission of BPA effects to the offspring and postulate that gender related differences might originate from differences in liver enzyme levels, such as UDP-glucuronosyltransferase, which is involved in BPA processing and its elimination from the organism. I discuss the molecular mechanisms of BPA action through nuclear and membrane-bound ER receptors, non-monotonic dose response, epigenetic modifications of the DNA and propose that chronic exposure to weak binders, such as BPA, may mimic the effects of strong binders, such as estrogens.

Transgenerational inheritance of susceptibility to diabetes-induced male subfertility

Male infertility is a worldwide problem associated with genetic background, environmental factors, and diseases. One of the suspected contributing factors to male infertility is diabetes mellitus. We investigated the molecular and morphological changes in sperms and testicular tissue of diabetic males. The study was performed in streptozotocin-induced type 1 diabetes mouse model. Diabetes decreased sperm concentration and viability and increased sperm apoptosis. Changes in protamine 1/protamine 2 ratio indicated reduced sperm quality. The testicular tissue of diabetic males showed significant tissue damage, disruption of meiotic progression, and changes in the expression of genes encoding proteins important for spermiogenesis. Paternal diabetes altered sperm quality and expression pattern in the testes in offspring of two subsequent generations. Our study revealed that paternal diabetes increased susceptibility to infertility in offspring through gametic alternations. Our data also provide a mechanistic basis for transgenerational inheritance of diabetes-associated pathologies since protamines may be involved in epigenetic regulations.

Gestational Exposure to Sidestream (Secondhand) Cigarette Smoke Promotes Transgenerational Epigenetic Transmission of Exacerbated Allergic Asthma and Bronchopulmonary Dysplasia

Embryonic development is highly sensitive to xenobiotic toxicity and in utero exposure to environmental toxins affects physiological responses of the progeny. In the United States, the prevalence of allergic asthma (AA) is inexplicably rising and in utero exposure to cigarette smoke increases the risk of AA and bronchopulmonary dysplasia (BPD) in children and animal models. We reported that gestational exposure to sidestream cigarette smoke (SS), or secondhand smoke, promoted nicotinic acetylcholine receptor-dependent exacerbation of AA and BPD in mice. Recently, perinatal nicotine injections in rats were reported to induce peroxisome proliferator-activated receptor γ-dependent transgenerational transmission of asthma. Herein, we show that first generation and second generation progeny from gestationally SS-exposed mice exhibit exacerbated AA and BPD that is not dependent on the decrease in peroxisome proliferator-activated receptor γ levels. Lungs from these mice show strong eosinophilic infiltration, excessive Th2 polarization, marked airway hyperresponsiveness, alveolar simplification, decreased lung compliance, and decreased lung angiogenesis. At the molecular level, these changes are associated with increased RUNX3 expression, alveolar cell apoptosis, and the antiangiogenic factor GAX, and decreased expression of HIF-1α and proangiogenic factors NF-κB and VEGFR2 in the 7-d first generation and second generation lungs. Moreover, the lungs from these mice exhibit lower levels of microRNA (miR)-130a and increased levels of miR-16 and miR-221. These miRs regulate HIF-1α-regulated apoptotic, angiogenic, and immune pathways. Thus the intergenerational effects of gestational SS involve epigenetic regulation of HIF-1α through specific miRs contributing to increased incidence of AA and BPD in the progenies.

Intrauterine diabetic milieu instigates dysregulated adipocytokines production in F1 offspring

Background

Intrauterine environment plays a pivotal role in the origin of fatal diseases such as the metabolic syndrome. Diabetes is associated with low-grade inflammatory state and dysregulated adipokines production. The aim of this study is to investigate the effect of maternal diabetes on adipocytokines (adiponectin, leptin and TNF-α) production in F1 offspring in rats.

Methods

The offspring groups were as follows: F1 offspring of control mothers under control diet (CD) (CF1-CD), F1 offspring of control mothers under high caloric diet (HCD) (CF1-HCD), F1 offspring of diabetic mothers under CD (DF1-CD), and F1 offspring of diabetic mothers under HCD (DF1-HCD). Every 5 weeks post-natal, 10 pups of each subgroup were culled to obtain blood samples for biochemical analysis.

Results

The results indicate that DF1-CD and DF1-HCD groups exhibited hyperinsulinemia, dyslipidemia, insulin resistance and impaired glucose homeostasis compared to CF1-CD (p > 0.05). DF1-CD and DF1-HCD groups had high hepatic and muscular depositions of TGs. The significant elevated NEFA level only appeared in offspring of diabetic mothers that was fed HCD. DF1-CD and DF1-HCD groups demonstrated low serum levels of adiponectin, high levels of leptin, and elevated levels of TNF-α compared to CF1-CD (p > 0.05). These results reveal the disturbed metabolic lipid profile of offspring of diabetic mothers and could guide further characterization of the mechanisms involved.

Conclusion

Dysregulated adipocytokines production could be a possible mechanism for the transgenerational transmittance of diabetes, especially following a postnatal diabetogenic environment. Moreover, the exacerbating effects of postnatal HCD on NEFA in rats might be prone to adipcytokine dysregulation. Furthermore, dysregulation of serum adipokines is a prevalent consequence of maternal diabetes and could guide further investigations to predict the development of metabolic disturbances.

Gestational Diabetes Mellitus:current knowledge and unmet needs

Gestational diabetes mellitus (GDM) is a global health concern, not only because its prevalence is high and on the increase, but also because of the potential implications for the health of mothers and their offspring. Unfortunately, there is considerable controversy in the literature surrounding the diagnosis and treatment of GDM, as well as the possible long-term consequences for the offspring. As a result, worldwide there is a lack of uniformly accepted diagnostic criteria and the advice regarding the treatment of GDM, including diet, insulin therapy, and the use of oral blood glucose-lowering agents, is highly variable. In this review we provide an overview of the important issues in the field of GDM, including diagnostic criteria, different treatment regimens available, and the long-term consequences of GDM in the offspring.

Sperm tsRNAs and acquired metabolic disorders

Many findings support the hypothesis that metabolic changes associated with environmental factors can be transmitted from father to offspring. The molecular mechanisms underlying the intergenerational transmission of metabolic changes remain to be fully explored. These acquired metabolic disorders in offspring may be partially explained by some potential epigenetic information carriers such as DNA methylation, histone modification and small non-coding RNAs. Recent evidence shows that sperm tRNA-derived small RNAs (tsRNAs) as a type of paternal epigenetic information carrier may mediate intergenerational inheritance. In this review, we provide current knowledge of a father's influence on metabolic disorders in subsequent generations and discuss the roles of sperm tsRNAs and their modifications in paternal epigenetic information transmission.

Impact of Maternal Glucose and Gestational Weight Gain on Child Obesity over the First Decade of Life in Normal Birth Weight Infants

Objective To determine, among children with normal birth weight, if maternal hyperglycemia and weight gain independently increase childhood obesity risk in a very large diverse population. Methods Study population was 24,141 individuals (mothers and their normal birth weight offspring, born 1995-2003) among a diverse population with universal GDM screening [50-g glucose-challenge test (GCT); 3 h. 100 g oral glucose tolerance test (OGTT) if GCT+]. Among the 13,037 full-term offspring with normal birth weight (2500-4000 g), annual measured height/weight was ascertained between ages 2 and 10 years to calculate gender-specific BMI-for-age percentiles using USA norms (1960-1995 standard). Results Among children who began life with normal birth weight, we found a significant trend for developing both childhood overweight (>85 %ile) and obesity (>95 %ile) during the first decade of life with both maternal hyperglycemia (normal GCT, GCT+ but no GDM, GDM) and excessive gestational weight gain [>40 pounds (18.1 kg)]; p < 0.0001 for both trends. These maternal glucose and/or weight gain effects to imprint for childhood obesity in the first decade remained after adjustment for potential confounders including maternal age, parity, as well as pre-pregnancy BMI. The attributable risk (%) for childhood obesity was 28.5 % (95 % CI 15.9-41.1) for GDM and 16.4 % (95 % CI 9.4-23.2) for excessive gestational weight gain. Conclusions for Practice Both maternal hyperglycemia and excessive weight gain have independent effects to increase childhood obesity risk. Future research should focus on prevention efforts during pregnancy as a potential window of opportunity to reduce childhood obesity.

Gestational diabetes mellitus and long-term consequences for mother and offspring: a view from Denmark

Gestational diabetes mellitus (GDM) is defined as glucose intolerance of varying severity and is present in about 2-6% of all pregnancies in Europe, making it one of the most common pregnancy disorders. Aside from the short-term maternal, fetal and neonatal consequences associated with GDM, there are long-term consequences for both mother and child. Although maternal glucose tolerance often normalises shortly after pregnancy, women with GDM have a substantially increased risk of developing type 2 diabetes later in life. Studies have reported that women are more than seven times as likely to develop diabetes after GDM, and that approximately 50% of mothers with GDM will develop diabetes within 10 years, making GDM one of the strongest predictors of type 2 diabetes. In women with previous GDM, development of type 2 diabetes can be prevented or delayed by lifestyle intervention and/or medical treatment. Systematic follow-up programmes would be ideal to prevent progression of GDM to diabetes, but such programmes are unfortunately lacking in the routine clinical set-up in most countries. Studies have found that the risks of obesity, the metabolic syndrome, type 2 diabetes and impaired insulin sensitivity and secretion in offspring of mothers with GDM are two- to eightfold those in offspring of mothers without GDM. The underlying pathogenic mechanisms behind the abnormal metabolic risk profile in offspring are unknown, but epigenetic changes induced by exposure to maternal hyperglycaemia during fetal life are implicated. Animal studies indicate that treatment can prevent long-term metabolic complications in offspring, but this remains to be confirmed in humans. Thus, diabetes begets diabetes and it is likely that GDM plays a significant role in the global diabetes epidemic. This review summarises a presentation given at the 'Gestational diabetes: what's up?' symposium at the 2015 annual meeting of the EASD. It is accompanied by two other reviews on topics from this symposium (by Marja Vääräsmäki, DOI: 10.1007/s00125-016-3976-6 , and by Cuilin Zhang and colleagues, DOI: 10.1007/s00125-016-3979-3 ) and an overview by the Session Chair, Kerstin Berntorp (DOI: 10.1007/s00125-016-3975-7 ).

Exposure to organophosphorus and organochlorine pesticides, perfluoroalkyl substances, and polychlorinated biphenyls in pregnancy and the association with impaired glucose tolerance and gestational diabetes mellitus: The MIREC Study

BACKGROUND

Studies report increases in rates of gestational diabetes mellitus (GDM) over recent decades. Environmental chemicals may increase the risk of diabetes through impacts on glucose metabolism, mitochondrial dysfunction, and endocrine-disrupting mechanisms including effects on pancreatic β-cell function and adiponectin release.

OBJECTIVES

To determine the associations between pesticides, perfluoroalkyl substances (PFASs) and polychlorinated biphenyls (PCBs) measured in early pregnancy and impaired glucose tolerance (IGT) and GDM in a Canadian birth cohort.

METHODS

Women enrolled in the Maternal-Infant Research on Environmental Chemicals (MIREC) Study were included if they had a singleton delivery and did not have pre-existing diabetes. Exposure variables included three organophosphorus (OP) pesticide metabolites detected in first-trimester urine samples, as well as three organochlorine (OC) pesticides, three PFASs, and four PCBs in first-trimester blood samples. Gestational IGT and GDM were assessed by chart review in accordance with published guidelines. Adjusted logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CI) for the association between quartiles of environmental chemicals and both gestational IGT and GDM.

RESULTS

Of the 2001 women recruited into the MIREC cohort, 1274 met the inclusion criteria and had outcome and biomonitoring data available. Significantly lower odds of GDM were observed in the third and fourth quartiles of dimethylphosphate (DMP) and in the fourth quartile of dimethylthiophosphate (DMTP) in adjusted analyses (DMP Q3: OR=0.2, 95% CI=0.1-0.7; DMP Q4: OR=0.3, 95% CI=0.1-0.8; DMTP: OR=0.3, 95% CI=0.1-0.9). Significantly elevated odds of gestational IGT was observed in the second quartile of perfluorohexane sulfonate (PFHxS) (OR=3.5, 95% CI=1.4-8.9). No evidence of associations with GDM or IGT during pregnancy was observed for PCBs or OC pesticides.

CONCLUSIONS

We did not find consistent evidence for any positive associations between the chemicals we examined and GDM or IGT during pregnancy. We observed statistical evidence of inverse relationships between urine concentrations of DMP and DMTP with GDM. We cannot rule out the influence of residual confounding due to unmeasured protective factors, such as nutritional benefits from fruit and vegetable consumption, also associated with pesticide exposure, on the observed inverse associations between maternal OP pesticide metabolites and GDM. These findings require further investigation.

Interrupting Intergenerational Cycles of Maternal Obesity

Factors operating in the preconception and prenatal periods, such as maternal obesity, excessive gestational weight gain and gestational diabetes, predict a substantial fraction of childhood obesity as well as lifelong adverse health consequences in the mother. These periods may lend themselves to successful intervention to reduce such risk factors because parents may be especially willing to change behavior if it confers health advantages to their children. If effective interventions started before or during pregnancy can be maintained after birth, they have the potential to lower the risk of both maternal obesity in the next pregnancy and obesity in the growing child, thus helping to interrupt maternal and child intergenerational vicious cycles of obesity, diabetes and related cardiometabolic health consequences. While this paradigm is appealing, challenges include determining the magnitude, causality and modifiability of these risk factors, and quantifying any adverse consequences of intervention.

Developmental Programming, a Pathway to Disease

Accumulating evidence suggests that insults occurring during the perinatal period alter the developmental trajectory of the fetus/offspring leading to long-term detrimental outcomes that often culminate in adult pathologies. These perinatal insults include maternal/fetal disease states, nutritional deficits/excess, stress, lifestyle choices, exposure to environmental chemicals, and medical interventions. In addition to reviewing the various insults that contribute to developmental programming and the benefits of animal models in addressing underlying mechanisms, this review focuses on the commonalities in disease outcomes stemming from various insults, the convergence of mechanistic pathways via which various insults can lead to common outcomes, and identifies the knowledge gaps in the field and future directions.

ENDOCRINOLOGY OF PREGNANCY: Gestational diabetes mellitus: definition, aetiological and clinical aspects

Gestational diabetes (GDM) is defined as a glucose intolerance resulting in hyperglycaemia of variable severity with onset during pregnancy. This review aims to revisit the pathogenesis and aetiology of GDM in order to better understand its clinical presentation and outcomes. During normal pregnancy, insulin sensitivity declines with advancing gestation. These modifications are due to placental factors, progesterone and estrogen. In a physiological situation, a compensatory increase in insulin secretion maintains a normal glucose homeostasis. GDM occurs if pancreatic β-cells are unable to face the increased insulin demand during pregnancy. GDM is most commonly a forerunner of type 2 diabetes (T2D) - the most prevalent form of diabetes. These women share similar characteristics with predisposed subjects to T2D: insulin resistance before and after pregnancy, and carry more T2D risk alleles. Auto-immune and monogenic diabetes are more rare aetiologies of GDM. Adverse pregnancy outcomes of GDM are mainly related to macrosomia caused by fetal hyperinsulinism in response to high glucose levels coming from maternal hyperglycaemia. Screening recommendations and diagnosis criteria of GDM have been recently updated. High risk patients should be screened as early as possible using fasting plasma glucose, and if normal, at 24-28 weeks of gestation using 75 g oral glucose tolerance test. The treatment of GDM is based on education with trained nurses and dieticians, and if necessary insulin therapy.

Transgenerational epigenetic inheritance of diabetes risk as a consequence of early nutritional imbalances

In today's world, there is an unprecedented rise in the prevalence of chronic metabolic diseases, including obesity, insulin resistance and type 2 diabetes (T2D). The pathogenesis of T2D includes both genetic and environmental factors, such as excessive energy intake and physical inactivity. It has recently been suggested that environmental factors experienced during early stages of development, including the intrauterine and neonatal periods, might play a major role in predisposing individuals to T2D. Furthermore, several studies have shown that such early environmental conditions might even contribute to disease risk in further generations. In this review, we summarise recent data describing how parental nutrition during development increases the risk of diabetes in the offspring. We also discuss the potential mechanisms underlying transgenerational inheritance of metabolic disease, with particular emphasis on epigenetic mechanisms.