Early-life origins of type 2 diabetes: fetal programming of the beta-cell mass

Using data on biomarkers and siblings to study early-life economic determinants of type-2 diabetes

We study the effect of economic conditions early in life on the occurrence of type-2 diabetes in adulthood using contextual economic indicators and within-sibling pair variation. We use data from Lifelines: a longitudinal cohort study and biobank including 51,270 siblings born in the Netherlands from 1950 onward. Sibling fixed-effects account for selective fertility. To identify type-2 diabetes we use biomarkers on the hemoglobin A1c concentration and fasting glucose in the blood. We find that adverse economic conditions around birth increase the probability of type-2 diabetes later in life both in males and in females. Inference based on self-reported diabetes leads to biased results, incorrectly suggesting the absence of an effect. The same applies to inference that does not account for selective fertility.

Pathogenesis of MASLD and MASH - role of insulin resistance and lipotoxicity

BACKGROUND

Insulin resistance and lipotoxicity are extremely interconnected but fundamental in setting the stage for the development of MASLD/MASH.

AIM/METHODS

A comprehensive literature search was performed and key themes were synthesised to provide insight into the underlying molecular mechanisms of insulin resistance and lipotoxicity in the liver, muscle, pancreas and adipose tissue and how organ cross-talk is fundamental to driving disease pathogenesis.

RESULTS

Classical thinking postulates that excess FFA load exceeds the storage capacity of adipose tissue, which is predicated upon both genetic and environmental factors. This results in insulin resistance and compensatory hyperinsulinaemia by pancreatic beta cells to overcome target organ insulin resistance. As adipocyte dysfunction worsens, not only are excess FFA delivered to other organs, including skeletal muscle, pancreas and liver but a pro-inflammatory milieu is established with increases in IL-6, TNF-α and changes in adipokine levels (increased leptin and decreased adiponectin). With increased intramuscular lipid accumulation, lipotoxic species decrease insulin signalling, reduce glucose uptake by downregulation of GLUT4 and decrease glycogen synthesis. With this additional reduced capacity, hyperglycaemia is further exacerbated and increased FFA are delivered to the liver. The liver has the largest capacity to oxidise fat and to adapt to these stressors and, therefore, has become the last line of defence for excess lipid storage and utilisation, the capacity of which may be impacted by genetic and environmental factors. However, when the liver can no longer keep up with increasing FFA delivery and DNL, lipotoxic species accumulate with ensuing mitochondrial dysfunction, increased ER stress, oxidant stress and inflammasome activation, all of which drive hepatocyte injury and apoptosis. The resulting wound healing response, marked by stellate cell activation, drives collagen accumulation, progressive fibrosis, and, ultimately, end organ failure and death. This vicious cycle and complex interplay between insulin resistance, hyperinsulinaemia, lipotoxicity and multi-directional cross-talk among different target organs are critical drivers of MASLD/MASH.

CONCLUSIONS

Targeting tissue-specific insulin resistance and hyperinsulinaemia while decreasing FFA load (lipotoxicity) through dietary and lifestyle changes remain the best upstream interventions.

Effect of transgenerational diabetes via maternal lineage in female rats

Aim

To investigate the transgenerational effect of maternal hyperglycemia on oxidative stress markers, lipid profile, glycemia, pancreatic beta (β)-cells, and reproductive outcomes in the F2 adult generation. Additionally, to expand the knowledge on transgenerational diabetes the F3 generation at birth will be evaluated.

Methods

On day 5 of postnatal life female Sprague-Dawley rat newborns (F0 generation) were distributed into two groups: Diabetic (Streptozotocin-STZ, 70 mg/kg body weight, subcutaneous route) and Control rats. Adult female rats from the F0 generation and subsequently the F1 generation were mated to obtain the F2 generation, which was distributed into F2 generation (granddaughters) from control (F2_C) and diabetic (F2_D) rats. Oral Glucose Tolerance Test (OGTT), the area under the curve (AUC), blood biochemical analyses, and pancreatic morphology were analyzed before pregnancy. Reproductive outcomes were performed at the end of pregnancy. At birth, the glycemia and body weight of F3_C and F3_D rats were determined. p < 0.05 was considered significant.

Results

F2_D had higher body weight, triglyceride levels, and percentage of insulin-immunostained cells, contributing to glucose intolerance, and insulin resistance before pregnancy. At day 21 of pregnancy, the F2_D showed increased embryonic losses before and after implantation (84.33 and 83.74 %, respectively). At birth, F3_D presented hyperglycemia, and 16.3 % of newborns were large for pregnancy age (LGA).

Conclusion

Diabetes induction since the neonatal period in the first generation (F0) led to transgenerational (F2 and F3 generations) changes via the maternal lineage of female rats, confirming the relevance of control strictly the glycemia all the time.

Progenies of gestational diabetes mellitus exhibit sex disparity in metabolism after respective therapies of insulin, glibenclamide, and metformin in dams during pregnancy

BACKGROUND

The aim of this study was to compare the sex-dependent intergenerational effects of insulin, glibenclamide, and metformin on glucose and lipid metabolism in the offspring born to GDM mice.

METHODS

The murine GDM was induced by high fat diet. The offspring were grouped based on the treatments in maternal mice. ITT and GTT were performed at 4th and 8th weeks of age, respectively. Serum levels of TC, TG, HDL-C, and LDL-C plus hepatic levels of TG and TC, were respectively determined by enzymatic kits. Western blotting was conducted to detect related proteins in the livers from offspring.

RESULTS

The dyslipidaemia, hepatic lipid abnormality, and insulin insensitivity caused by GDM were persistently normalised in male adult offspring by the respective therapies of insulin, glibenclamide, and metformin during maternal pregnancy. Specifically, the decreases in plasma TC, TG, and LDL-C levels (29%, 37.8%, and 57.7%, respectively, p ˂ .05) and in hepatic lipid contents (TC 31.3% and TG 39.2%, p ˂ .05), the increases in hepatic phosphorylation levels of AKT, CPT1A, PPAR-α, and PPAR-γ (57.1%, 91.7%, 68%, and 173.3%, respectively, p ˂ .05) and the inhibition of G6Pase, PEPCK, and HMGCS1 (35.7%, 68.8%, and 77.3% respectively, p ˂ .05) were still observed in the male offspring born to treated GDM mice from 4th to 8th week of age. Unexpectedly, the aforementioned parameters in female progenies in different groups were not significantly changed compared with controls.

CONCLUSIONS

Respective treatments in GDM mice during pregnancy with insulin, glibenclamide, and metformin have the long-term persistent effects in male offspring, while female progenies born to untreated dams showed an autonomous inhibition of intergenerational relay of glucose and lipid dysregulation. Our current findings may imply a sex-dependent strategy of medical care for GDM mothers and their offspring.NoveltiesRespective interventions of insulin, glibenclamide, and metformin on dams exerted the persisted effects on male progenies.Therapies of three drugs on dams had the similarly improved effects in offspring.Female offspring autonomously corrected their dysregulated glucose-lipid metabolism caused by gestational diabetes mellitus (GDM) in dams.

Emerging therapeutic options in the management of diabetes: recent trends, challenges and future directions

Diabetes is a serious health issue that causes a progressive dysregulation of carbohydrate metabolism due to insufficient insulin hormone, leading to consistently high blood glucose levels. According to the epidemiological data, the prevalence of diabetes has been increasing globally, affecting millions of individuals. It is a long-term condition that increases the risk of various diseases caused by damage to small and large blood vessels. There are two main subtypes of diabetes: type 1 and type 2, with type 2 being the most prevalent. Genetic and molecular studies have identified several genetic variants and metabolic pathways that contribute to the development and progression of diabetes. Current treatments include gene therapy, stem cell therapy, statin therapy, and other drugs. Moreover, recent advancements in therapeutics have also focused on developing novel drugs targeting these pathways, including incretin mimetics, SGLT2 inhibitors, and GLP-1 receptor agonists, which have shown promising results in improving glycemic control and reducing the risk of complications. However, these treatments are often expensive, inaccessible to patients in underdeveloped countries, and can have severe side effects. Peptides, such as glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), are being explored as a potential therapy for diabetes. These peptides are postprandial glucose-dependent pancreatic beta-cell insulin secretagogues and have received much attention as a possible treatment option. Despite these advances, diabetes remains a major health challenge, and further research is needed to develop effective treatments and prevent its complications. This review covers various aspects of diabetes, including epidemiology, genetic and molecular basis, and recent advancements in therapeutics including herbal and synthetic peptides.

Promoting REproductive Planning And REadiness in Diabetes (PREPARED) Study protocol: a clinic-randomised controlled trial testing a technology-based strategy to promote preconception care for women with type 2 diabetes

INTRODUCTION

Women with type 2 diabetes (T2DM) are more likely to experience adverse reproductive outcomes, yet preconception care can significantly reduce these risks. For women with T2DM, preconception care includes reproductive planning and patient education on: (1) the importance of achieving glycaemic control before pregnancy, (2) using effective contraception until pregnancy is desired, (3) discontinuing teratogenic medications if pregnancy could occur, (4) taking folic acid, and (5) managing cardiovascular and other risks. Despite its importance, few women with T2DM receive recommended preconception care.

METHODS AND ANALYSIS

We are conducting a two-arm, clinic-randomised trial at 51 primary care practices in Chicago, Illinois to evaluate a technology-based strategy to 'hardwire' preconception care for women of reproductive age with T2DM (the PREPARED (Promoting REproductive Planning And REadiness in Diabetes) strategy) versus usual care. PREPARED leverages electronic health record (EHR) technology before and during primary care visits to: (1) promote medication safety, (2) prompt preconception counselling and reproductive planning, and (3) deliver patient-friendly educational tools to reinforce counselling. Post-visit, text messaging is used to: (4) encourage healthy lifestyle behaviours. English and Spanish-speaking women, aged 18-44 years, with T2DM will be enrolled (N=840; n=420 per arm) and will receive either PREPARED or usual care based on their clinic's assignment. Data will be collected from patient interviews and the EHR. Outcomes include haemoglobin A1c (primary), reproductive knowledge and self-management behaviours. We will use generalised linear mixed-effects models (GLMMs) to evaluate the impact of PREPARED on these outcomes. GLMMs will include a fixed effect for treatment assignment (PREPARED vs usual care) and random clinic effects.

ETHICS AND DISSEMINATION

This study was approved by the Northwestern University Institutional Review Board (STU00214604). Study results will be published in journals with summaries shared online and with participants upon request.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT04976881).

Maternal micronutrient disturbance as risks of offspring metabolic syndrome

Metabolic syndrome (MetS) is defined as a constellation of individual metabolic disturbances, including central obesity, hypertension, dyslipidemia, and insulin resistance. The established pathogenesis of MetS varies extensively with gender, age, ethnic background, and nutritional status. In terms of nutritional status, micronutrients are more likely to be discounted as essential components of required nutrition than macronutrients due to the small amount required. Numerous observational studies have shown that pregnant women frequently experience malnutrition, especially in developing and low-income countries, resulting in chronic MetS in the offspring due to the urgent and increasing demands for micronutrients during gestation and lactation. Over the past few decades, scientific developments have revolutionized our understanding of the association between balanced maternal micronutrients and MetS in the offspring. Examples of successful individual, dual, or multiple maternal micronutrient interventions on the offspring include iron for hypertension, selenium for type 2 diabetes, and a combination of folate and vitamin D for adiposity. In this review, we aim to elucidate the effects of maternal micronutrient intake on offspring metabolic homeostasis and discuss potential perspectives and challenges in the field of maternal micronutrient interventions.

Single-Cell Chromatin Accessibility Data Combined with GWAS Improves Detection of Relevant Cell Types in 59 Complex Phenotypes

Several disease risk variants reside on non-coding regions of DNA, particularly in open chromatin regions of specific cell types. Identifying the cell types relevant to complex traits through the integration of chromatin accessibility data and genome-wide association studies (GWAS) data can help to elucidate the mechanisms of these traits. In this study, we created a collection of associations between the combinations of chromatin accessibility data (bulk and single-cell) with an array of 201 complex phenotypes. We integrated the GWAS data of these 201 phenotypes with bulk chromatin accessibility data from 137 cell types measured by DNase-I hypersensitive sequencing and found significant results (FDR adjusted p-value ≤ 0.05) for at least one cell type in 21 complex phenotypes, such as atopic dermatitis, Graves’ disease, and body mass index. With the integration of single-cell chromatin accessibility data measured by an assay for transposase-accessible chromatin with high-throughput sequencing (scATAC-seq), taken from 111 adult and 111 fetal cell types, the resolution of association was magnified, enabling the identification of further cell types. This resulted in the identification of significant correlations (FDR adjusted p-value ≤ 0.05) between 15 categories of single-cell subtypes and 59 phenotypes ranging from autoimmune diseases like Graves’ disease to cardiovascular traits like diastolic/systolic blood pressure.

The association between birth weight, ponderal index, psychotropic medication, and type 2 diabetes in individuals with severe mental illness

BACKGROUND

Impaired fetal growth may increase vulnerability towards metabolic disturbances associated with some medications. We examined whether birth weight and ponderal index modify the association between psychotropic medication and type 2 diabetes among young adults with severe psychiatric diagnosis.

METHODS

A total of 36,957 individuals born in Denmark between 1973 and 1983 with a diagnosis of schizophrenia, bipolar disorder, or depression were followed from first diagnosis until 2018. Cox proportional hazard models were applied to analyse risk of type 2 diabetes with use of psychotropic medications and interactions between psychotropic medication and birth weight and ponderal index, respectively.

RESULTS

During follow-up, 1575 (4.2%) individuals received a diagnosis of type 2 diabetes. Use of antipsychotic, mood stabilizing and antidepressant medications were associated with higher hazard ratios (HRs) of type 2 diabetes (HR_{antipsychotics} 1.68 [95%CI 1.49-1.90]; HR_{mood stabilizing medication} 1.41 [95%CI 1.25-1.59]; HR_{antidepressants} 2.00 [95%CI 1.68-2.37]), as were a birth weight below 2500 g (HR 1.13 [95%CI 1.01-1.28]), and high ponderal index (HR 1.26 [95%CI 1.11-1.43]). The highest rates of type 2 diabetes for each psychotropic medication category were found in medication users with low birth weight or high ponderal index. However, neither birth weight nor ponderal index significantly modified the association between psychotropic medication and diabetes risk.

CONCLUSION

Psychotropic medication use, birth weight, and ponderal index were risk factors for type 2 diabetes in patients with severe mental illness, but neither birth weight nor ponderal index modified the association between psychotropic medication and type 2 diabetes.

Dichotomy in the Impact of Elevated Maternal Glucose Levels on Neonatal Epigenome

CONTEXT

Antenatal hyperglycemia is associated with increased risk of future adverse health outcomes in both mother and child. Variations in offspring's epigenome can reflect the impact and response to in utero glycemic exposure, and may have different consequences for the child.

OBJECTIVE

We examined possible differences in associations of basal glucose status and glucose handling during pregnancy with both clinical covariates and offspring cord tissue DNA methylation.

RESEARCH DESIGN AND METHODS

This study included 830 mother-offspring dyads from the Growing Up in Singapore Towards Healthy Outcomes cohort. The fetal epigenome of umbilical cord tissue was profiled using Illumina HumanMethylation450 arrays. Associations of maternal mid-pregnancy fasting (fasting plasma glucose [FPG]) and 2-hour plasma glucose (2hPG) after a 75-g oral glucose challenge with both maternal clinical phenotypes and offspring epigenome at delivery were investigated separately.

RESULTS

Maternal age, prepregnancy body mass index, and blood pressure measures were associated with both FPG and 2hPG, whereas Chinese ethnicity (P = 1.9 × 10-4), maternal height (P = 1.1 × 10-4), pregnancy weight gain (P = 2.2 × 10-3), prepregnancy alcohol consumption (P = 4.6 × 10-4), and tobacco exposure (P = 1.9 × 10-3) showed significantly opposite associations between the 2 glucose measures. Most importantly, we observed a dichotomy in the effects of these glycemic indices on the offspring epigenome. Offspring born to mothers with elevated 2hPG showed global hypomethylation. CpGs most associated with the 2 measures also reflected differences in gene ontologies and had different associations with offspring birthweight.

CONCLUSIONS

Our findings suggest that 2 traditionally used glycemic indices for diagnosing gestational diabetes may reflect distinctive pathophysiologies in pregnancy, and have differential impacts on the offspring's DNA methylome.

Beta-Cell Adaptation to Pregnancy - Role of Calcium Dynamics

During pregnancy, the mother develops insulin resistance to shunt nutrients to the growing fetus. As a result, the maternal islets of Langerhans undergo several changes to increase insulin secretion in order to maintain glucose homeostasis and prevent the development of gestational diabetes. These changes include an increase in β-cell proliferation and β-cell mass, upregulation of insulin synthesis and insulin content, enhanced cell-to-cell communication, and a lowering of the glucose threshold for insulin secretion, all of which resulting in an increase in glucose-stimulated insulin secretion. Emerging data suggests that a change in intracellular calcium dynamics occurs in the β-cell during pregnancy as part of the adaptive process. Influx of calcium into β-cells is crucial in the regulation of glucose-stimulated insulin secretion. Calcium fluxes into and out of the cytosol, endoplasmic reticulum, and mitochondria are also important in controlling β-cell function and survival. Here, we review calcium dynamics in islets in response to pregnancy-induced changes in hormones and signaling molecules, and how these changes may enhance insulin secretion to stave off gestational diabetes.

Hyperinsulinemia and Its Pivotal Role in Aging, Obesity, Type 2 Diabetes, Cardiovascular Disease and Cancer

For many years, the dogma has been that insulin resistance precedes the development of hyperinsulinemia. However, recent data suggest a reverse order and place hyperinsulinemia mechanistically upstream of insulin resistance. Genetic background, consumption of the “modern” Western diet and over-nutrition may increase insulin secretion, decrease insulin pulses and/or reduce hepatic insulin clearance, thereby causing hyperinsulinemia. Hyperinsulinemia disturbs the balance of the insulin–GH–IGF axis and shifts the insulin : GH ratio towards insulin and away from GH. This insulin–GH shift promotes energy storage and lipid synthesis and hinders lipid breakdown, resulting in obesity due to higher fat accumulation and lower energy expenditure. Hyperinsulinemia is an important etiological factor in the development of metabolic syndrome, type 2 diabetes, cardiovascular disease, cancer and premature mortality. It has been further hypothesized that nutritionally driven insulin exposure controls the rate of mammalian aging. Interventions that normalize/reduce plasma insulin concentrations might play a key role in the prevention and treatment of age-related decline, obesity, type 2 diabetes, cardiovascular disease and cancer. Caloric restriction, increasing hepatic insulin clearance and maximizing insulin sensitivity are at present the three main strategies available for managing hyperinsulinemia. This may slow down age-related physiological decline and prevent age-related diseases. Drugs that reduce insulin (hyper) secretion, normalize pulsatile insulin secretion and/or increase hepatic insulin clearance may also have the potential to prevent or delay the progression of hyperinsulinemia-mediated diseases. Future research should focus on new strategies to minimize hyperinsulinemia at an early stage, aiming at successfully preventing and treating hyperinsulinemia-mediated diseases.

Pancreatic progenitor epigenome maps prioritize type 2 diabetes risk genes with roles in development

Genetic variants associated with type 2 diabetes (T2D) risk affect gene regulation in metabolically relevant tissues, such as pancreatic islets. Here, we investigated contributions of regulatory programs active during pancreatic development to T2D risk. Generation of chromatin maps from developmental precursors throughout pancreatic differentiation of human embryonic stem cells (hESCs) identifies enrichment of T2D variants in pancreatic progenitor-specific stretch enhancers that are not active in islets. Genes associated with progenitor-specific stretch enhancers are predicted to regulate developmental processes, most notably tissue morphogenesis. Through gene editing in hESCs, we demonstrate that progenitor-specific enhancers harboring T2D-associated variants regulate cell polarity genes LAMA1 and CRB2. Knockdown of lama1 or crb2 in zebrafish embryos causes a defect in pancreas morphogenesis and impairs islet cell development. Together, our findings reveal that a subset of T2D risk variants specifically affects pancreatic developmental programs, suggesting that dysregulation of developmental processes can predispose to T2D.

Impact of Early Nutrition, Physical Activity and Sleep on the Fetal Programming of Disease in the Pregnancy: A Narrative Review

Early programming is the adaptation process by which nutrition and environmental factors alter development pathways during prenatal growth, inducing changes in postnatal metabolism and diseases. The aim of this narrative review, is evaluating the current knowledge in the scientific literature on the effects of nutrition, environmental factors, physical activity and sleep on development pathways. If in utero adaptations were incorrect, this would cause a mismatch between prenatal programming and adulthood. Adequate caloric intake, protein, mineral, vitamin, and long-chain fatty acids, have been noted for their relevance in the offspring brain functions and behavior. Fetus undernutrition/malnutrition causes a delay in growth and have detrimental effects on the development and subsequent functioning of the organs. Pregnancy is a particularly vulnerable period for the development of food preferences and for modifications in the emotional response. Maternal obesity increases the risk of developing perinatal complications and delivery by cesarean section and has long-term implications in the development of metabolic diseases. Physical exercise during pregnancy contributes to overall improved health post-partum. It is also interesting to highlight the relevance of sleep problems during pregnancy, which influence adequate growth and fetal development. Taking into account these considerations, we conclude that nutrition and metabolic factors during early life play a key role of health promotion and public health nutrition programs worldwide to improve the health of the offspring and the health costs of hospitalization.

Maternal hypothyroidism in mice influences glucose metabolism in adult offspring

AIMS/HYPOTHESIS

During pregnancy, maternal metabolic disease and hormonal imbalance may alter fetal beta cell development and/or proliferation, thus leading to an increased risk for developing type 2 diabetes in adulthood. Although thyroid hormones play an important role in fetal endocrine pancreas development, the impact of maternal hypothyroidism on glucose homeostasis in adult offspring remains poorly understood.

METHODS

We investigated this using a mouse model of hypothyroidism, induced by administration of an iodine-deficient diet supplemented with propylthiouracil during gestation.

RESULTS

Here, we show that, when fed normal chow, adult mice born to hypothyroid mothers were more glucose-tolerant due to beta cell hyperproliferation (two- to threefold increase in Ki67-positive beta cells) and increased insulin sensitivity. However, following 8 weeks of high-fat feeding, these offspring gained 20% more body weight, became profoundly hyperinsulinaemic (with a 50% increase in fasting insulin concentration), insulin-resistant and glucose-intolerant compared with controls from euthyroid mothers. Furthermore, altered glucose metabolism was maintained in a second generation of animals.

CONCLUSIONS/INTERPRETATION

Therefore, gestational hypothyroidism induces long-term alterations in endocrine pancreas function, which may have implications for type 2 diabetes prevention in affected individuals.

Psychological Stress, Intestinal Barrier Dysfunctions, and Autoimmune Disorders: An Overview

Autoimmune disorders (ADs) are multifactorial diseases involving, genetic, epigenetic, and environmental factors characterized by an inappropriate immune response toward self-antigens. In the past decades, there has been a continuous rise in the incidence of ADs, which cannot be explained by genetic factors alone. Influence of psychological stress on the development or the course of autoimmune disorders has been discussed for a long time. Indeed, based on epidemiological studies, stress has been suggested to precede AD occurrence and to exacerbate symptoms. Furthermore, compiling data showed that most of ADs are associated with gastrointestinal symptoms, that is, microbiota dysbiosis, intestinal hyperpermeability, and intestinal inflammation. Interestingly, social stress (acute or chronic, in adult or in neonate) is a well-described intestinal disrupting factor. Taken together, those observations question a potential role of stress-induced defect of the intestinal barrier in the onset and/or the course of ADs. In this review, we aim to present evidences supporting the hypothesis for a role of stress-induced intestinal barrier disruption in the onset and/or the course of ADs. We will mainly focus on autoimmune type 1 diabetes, multiple sclerosis and systemic lupus erythematosus, ADs for which we could find sufficient circumstantial data to support this hypothesis. We excluded gastrointestinal (GI) ADs like coeliac disease to privilege ADs not focused on intestinal disorders to avoid confounding factors. Indeed, GIADs are characterized by antibodies directed against intestinal barrier actors.

The Constitutive Lack of α7 Nicotinic Receptor Leads to Metabolic Disorders in Mouse

Objective: Type 2 diabetes (T2D) occurs by deterioration in pancreatic β-cell function and/or progressive loss of pancreatic β-cell mass under the context of insulin resistance. α7 nicotinic acetylcholine receptor (nAChR) may contribute to insulin sensitivity but its role in the pathogenesis of T2D remains undefined. We investigated whether the systemic lack of α7 nAChR was sufficient to impair glucose homeostasis. Methods: We used an α7 nAChR knock-out (α7^−/−) mouse model fed a standard chow diet. The effects of the lack of α7 nAChR on islet mass, insulin secretion, glucose and insulin tolerance, body composition, and food behaviour were assessed in vivo and ex vivo experiments. Results: Young α7^−/− mice display a chronic mild high glycemia combined with an impaired glucose tolerance and a marked deficit in β-cell mass. In addition to these metabolic disorders, old mice developed adipose tissue inflammation, elevated plasma free fatty acid concentrations and presented glycolytic muscle insulin resistance in old mice. Finally, α7^−/− mice, fed a chow diet, exhibited a late-onset excessive gain in body weight through increased fat mass associated with higher food intake. Conclusion: Our work highlights the important role of α7 nAChR in glucose homeostasis. The constitutive lack of α7 nAChR suggests a novel pathway influencing the pathogenesis of T2D.

Tissues derived from reprogrammed Wharton's jelly stem cells of the umbilical cord as a platform to study gestational diabetes mellitus

Gestational diabetes mellitus (GDM) has been strongly associated with an increased risk of type 2 diabetes mellitus (T2DM) in later child and adulthood. The human umbilical cord and its contents are of fetal origin and represent the fetus genetically and physiologically. Since it is not possible to obtain tissues from the fetus and newborn to investigate the association between GDM and later T2DM, we reprogrammed the stem cells from the Wharton's jelly of umbilical cords (hWJSCs) of GDM and non-GDM mothers into induced pluripotent stem cells (iPSCs) and then differentiated the iPSCs into insulin-producing cells (IPCs) to provide pancreatic tissues that represent the fetus of GDM and normal mothers. These tissues are an attractive model to study the effects of glucose on the fetus. Interestingly, GDM-iPSCs had a decreased potential towards differentiation into IPCs. IPCs differentiated from GDM-iPSCs also had lower total insulin content and a lower capacity for insulin secretion to glucose stimulation compared to their normal-iPSC counterparts. This abnormal pathogenesis in GDM-iPSCs pancreatic differentiation recapitulates the pathology that may be observed in the infants of the diabetic mother (IDM) and while indicating adaptive mechanisms for fetal survival, may lead to the development of T2DM later in life. (199 words).

Intergenerational transmission of the effects of maternal exposure to childhood maltreatment on offspring obesity risk: A fetal programming perspective

Childhood obesity constitutes a major global public health challenge. A substantial body of evidence suggests that conditions and states experienced by the embryo/fetus in utero can result in structural and functional changes in cells, tissues, organ systems and homeostatic set points related to obesity. Furthermore, growing evidence suggests that maternal conditions and states experienced prior to conception, such as stress, obesity and metabolic dysfunction, may spill over into pregnancy and influence those key aspects of gestational biology that program offspring obesity risk. In this narrative review, we advance a novel hypothesis and life-span framework to propose that maternal exposure to childhood maltreatment may constitute an important and as-yet-underappreciated risk factor implicated in developmental programming of offspring obesity risk via the long-term psychological, biological and behavioral sequelae of childhood maltreatment exposure. In this context, our framework considers the key role of maternal-placental-fetal endocrine, immune and metabolic pathways and also other processes including epigenetics, oocyte mitochondrial biology, and the maternal and infant microbiomes. Finally, our paper discusses future research directions required to elucidate the nature and mechanisms of the intergenerational transmission of the effects of maternal childhood maltreatment on offspring obesity risk.

Increased Susceptibility to Obesity and Glucose Intolerance in Adult Female Rats Programmed by High-Protein Diet during Gestation, But Not during Lactation

Fetal and early postnatal nutritional environments contribute to lifelong health. High-protein (HP) intake in early life can increase obesity risk in response to specific feeding conditions after weaning. This study investigated the effects of a maternal HP diet during pregnancy and/or lactation on the metabolic health of offspring. Three groups of dams received a normal-protein (NP, 20E% proteins) diet during gestation and lactation (Control group), an HP diet (55E% proteins) during gestation (HPgest group), or an HP diet during lactation (HPlact group). From weaning until 10 weeks, female pups were exposed to the NP, the HP or the western (W) diet. HPgest pups had more adipocytes (p = 0.009), more subcutaneous adipose tissue (p = 0.04) and increased expression of genes involved in liver fatty acid synthesis at 10 weeks (p < 0.05). HPgest rats also showed higher food intake and adiposity under the W diet compared to the Control and HPlact rats (p ≤ 0.04). The post-weaning HP diet reduced weight (p < 0.0001), food intake (p < 0.0001), adiposity (p < 0.0001) and glucose tolerance (p < 0.0001) compared to the NP and W diets; this effect was enhanced in the HPgest group (p = 0.04). These results show that a maternal HP diet during gestation, but not lactation, leads to a higher susceptibility to obesity and glucose intolerance in female offspring.

Inflammatory Consequences of Maternal Diabetes on the Offspring Brain: a Hippocampal Organotypic Culture Study

Gestational diabetes is a disorder associated with abnormal chronic inflammation that poses a risk to the developing fetus. We investigated the effects of experimentally induced diabetes (streptozotocin model) in Wistar female rats on the inflammatory status of the hippocampi of their offspring. Additionally, the impact of antidiabetic drugs (metformin and glyburide) on inflammatory processes was evaluated. Organotypic hippocampal cultures (OHCs) were prepared from the brains of the 7-day-old rat offspring of control and diabetic mother rats. On the 7th day in vitro, the cultures were pretreated with metformin (3 μM) or glyburide (1 μM) and then stimulated for 24 h with lipopolysaccharide (LPS, 1 μg/ml). The OHCs obtained from the offspring of diabetic mothers were characterized by the increased mortality of cells and an enhanced susceptibility to damage caused by LPS. Although we showed that LPS stimulated the secretion of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in the control and diabetic cultures, the levels of IL-1β and IL-6 in the OHC medium obtained from the offspring of diabetic mothers were more pronounced. In the diabetic cultures, enhanced levels of TLR-4 and the overactivation of the NLRP3 inflammasome were demonstrated. Metformin and glyburide pretreatment normalized the LPS-induced IL-1β secretion in the control and diabetic cultures. Furthermore, glyburide diminished both: LPS-induced IL-6 and TNF-α secretion in the control and diabetic cultures and increased NF-κB p65 subunit phosphorylation. Glyburide also diminished the levels of the NLRP3 subunit and caspase-1, but only in the diabetic cultures. The results showed that maternal diabetes affected inflammatory processes in the offspring brain and increased hippocampal sensitivity to the LPS-induced inflammatory response. The use of antidiabetic agents, especially glyburide, had a beneficial impact on the changes caused by maternal diabetes.

Gestational Diabetes Adversely Affects Pancreatic Islet Architecture and Function in the Male Rat Offspring

Fetal exposure to gestational diabetes mellitus (GDM) and poor postnatal diet are strong risk factors for type 2 diabetes development later in life, but the mechanisms connecting GDM exposure to offspring metabolic health remains unclear. In this study, we aimed to determine how GDM interacts with the postnatal diet to affect islet function in the offspring as well as characterize the gene expression changes in the islets. GDM was induced in female rats using a high-fat, high-sucrose (HFS) diet, and litters from lean or GDM dams were weaned onto a low-fat (LF) or HFS diet. Compared with the lean control offspring, GDM exposure reduced glucose-stimulated insulin secretion in islets isolated from 15-week-old offspring, which was additively worsened when GDM exposure was combined with postnatal HFS diet consumption. In the HFS diet-fed offspring of lean dams, islet size and number increased, an adaptation that was not observed in the HFS diet-fed offspring of GDM dams. Islet gene expression in the offspring of GDM dams was altered in such categories as inflammation (e.g., Il1b, Ccl2), mitochondrial function/oxidative stress resistance (e.g., Atp5f1, Sod2), and ribosomal proteins (e.g., Rps6, Rps14). These results demonstrate that GDM exposure induced marked changes in gene expression in the male young adult rat offspring that cumulatively interact to worsen islet function, whole-body glucose homeostasis, and adaptations to HFS diets.

Birthweight correlates with later metabolic abnormalities in Chinese patients with maturity-onset diabetes of the young type 2

PURPOSE

Glucokinase-maturity onset diabetes of the young (GCK-MODY), also known as MODY2, is caused by heterozygous inactivating mutations in the GCK gene. The aim of this study is to investigate the relationship of birthweight and cardiometabolic characteristics in MODY2 patients.

METHODS

Genetic screening for GCK mutations from 192 classical MODY families was performed, and birthweight and clinical profiles of 76 patients from 25 families with identified GCK mutations were collected.

RESULTS

Mutations in GCK were identified in 25 (13%) of the 192 families. Four novel (c.1334 G > C, c.1289_1294delTGACGC, c.584 T > C, and c.30delC) and twenty-one previously reported mutations were identified and cosegregated with the clinical phenotypes of MODY2 within the pedigrees. MODY2 patients presented a mean birthweight of 3.11 ± 0.44 kg. Additionally, birthweight was negatively correlated with 2 h-postprandial glucose (r = -0.426, P = 0.006), glycated albumin (r = -0.462, P = 0.035), glycated hemoglobin (r = -0.529, P = 0.001), total cholesterol (r = -0.430, P = 0.016), and low-density lipoprotein cholesterol (LDL-C) (r = -0.383, P = 0.033) levels after adjustment for age, gender and BMI. Importantly, among the patients who inherited mutations from their mothers, 7 patients whose mothers were treated with insulin during pregnancy had particularly lower birthweight (2.83 ± 0.39 vs. 3.37 ± 0.39 kg; P = 0.003), higher total cholesterol (6.15 ± 0.43 vs. 4.06 ± 0.16 mmol/L; P = 0.002) and LDL-C (4.05 ± 0.35 vs. 2.21 ± 0.13 mmol/L; P = 0.001) levels compared to the other 21 patients whose mothers received no treatment.

CONCLUSIONS

The correlations between birthweight and cardiometabolic indexes indicated that MODY2 patients with lower birthweight (<3.1 kg) should be monitored and treated more actively to prevent metabolic abnormalities, particularly dyslipidemia. Importantly, prenatal genic diagnosis is highly recommended to avoid inappropriate treatment in pregnancy leading to lower birthweight of offspring.

(-)-Epicatechin reduces adiposity in male offspring of obese rats

Objective:

To determine whether (-)-epicatechin (Epi) could decrease visceral adipose tissue and improve the metabolic profile of male offspring rats, after maternal obesity was induced by a high-fat diet (HFD).

Design:

Maternal obesity in albino Wistar rats was induced with a HFD, whereas male offspring were fed with chow diet throughout the study. Eight male offspring per group, from different litters, were randomly assigned to the experimental or to the control groups. In the experimental group, Epi was administered at a dose of 1 mg/kg of body weight to the male offspring twice daily for two weeks, beginning at postnatal day (PND).

Main measures:

Weight of visceral adipose tissue, adipocyte size, and several metabolic parameters.

Results:

Epi administration in the male offspring induced a significant decrease in the amount of visceral fat (11.61 g less, P < 0.05) and in the size of adipose cells (28% smaller, P < 0.01). Besides, Epi was able to decrease insulin, leptin, and Homeostasis Model Assessment -Insulin Resistance (HOMA-IR) (P < 0.05), as well as triglycerides, when the experimental group was compared to the untreated male offspring of obese rats (P < 0.01).

Conclusions:

Epi administration can reverse the negative effects that maternal obesity has on the male offspring. This could be because Epi reduces the amount of visceral fat and improves metabolic profile.

Dysglycaemia, Inflammation and Psychosis: Findings From the UK ALSPAC Birth Cohort

BACKGROUND

Psychosis is associated with both dysglycaemia and low-grade inflammation, but population-based studies investigating the interplay between these factors are scarce.

AIMS

(1) To explore the direction of association between markers of dysglycaemia, inflammation and psychotic experiences (PEs); and (2) To explore whether dysglycaemia moderates and/or mediates the association between inflammation and PEs.

METHOD

Data from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort were modeled using logistic and linear regression to examine cross-sectional and longitudinal associations between markers of dysglycaemia (ages 9 and 18), interleukin-6 (IL-6) (age 9), and PEs (ages 12 and 18). We tested for an interaction between dysglycaemia and IL-6 on risk of PEs at age 18, and tested whether dysglycaemia mediated the relationship between IL-6 and PEs.

RESULTS

Based on 2627 participants, at age 18, insulin resistance (IR) was associated with PEs (adjusted OR = 2.32; 95% CI, 1.37-3.97). IR was associated with IL-6 both cross-sectionally and longitudinally. Interaction analyses under a multiplicative model showed that IR moderated the association between IL-6 at age 9 and PEs at age 18 (adjusted OR for interaction term = 2.18; 95% C.I., 1.06-4.49). Mediation analysis did not support a model of IR mediating the relationship between IL-6 and PEs.

IMPLICATIONS

IR is associated with PEs in young people even before the onset of clinical psychosis. Metabolic alterations may interact with childhood inflammation to increase risk of PEs. The findings have implications for clinical practice and future research.

Contraceptive Use Among Women with Prediabetes and Diabetes in a US National Sample

INTRODUCTION

Although elevated blood glucose is associated with adverse maternal and fetal health outcomes, evidence suggests that women with diabetes may not be receiving comprehensive reproductive health care, including family planning and preconception care. Using a population-based sample, we evaluated the relationship between contraceptive use and biomarker-identified diabetes.

METHODS

This cross-sectional study used data from 5548 women in the nationally representative National Longitudinal Study of Adolescent to Adult Health (Add Health) from 2007 to 2009. Women were aged 24 to 32 years, sexually active with men, and not pregnant. Hemoglobin A1C identified prediabetes and diabetes from blood specimens. The primary outcome was most effective contraception used in the past year: more effective (sterilization, intrauterine device, implant, combined hormonal methods, or injectable), less effective (condoms, diaphragms, spermicides, natural family planning, or withdrawal), or none. Multinomial regression models were adjusted for race and ethnicity, education, insurance, health care access, and body mass index.

RESULTS

Of the women with diabetes, 37.6% used more effective contraception, 33.6% less effective contraception, and 28.8% none. Women with diabetes had higher odds of using no contraception, rather than more effective contraception, than women with normoglycemia (adjusted odds ratio [aOR], 1.90; 95% CI, 1.25-2.87). Women with diabetes who were undiagnosed had greater odds of using less effective contraception, rather than more effective contraception, compared with those who were diagnosed (aOR 3.39; 95% CI, 1.44-7.96). Contraceptive use did not differ between women with prediabetes and normoglycemia.

DISCUSSION

Less effective contraceptive methods were commonly used by women with diabetes. Midwives and other women's health care providers can support women with diabetes to reach their pregnancy goals by providing preconception care and family planning.

The Pathophysiology of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a serious pregnancy complication, in which women without previously diagnosed diabetes develop chronic hyperglycemia during gestation. In most cases, this hyperglycemia is the result of impaired glucose tolerance due to pancreatic β-cell dysfunction on a background of chronic insulin resistance. Risk factors for GDM include overweight and obesity, advanced maternal age, and a family history or any form of diabetes. Consequences of GDM include increased risk of maternal cardiovascular disease and type 2 diabetes and macrosomia and birth complications in the infant. There is also a longer-term risk of obesity, type 2 diabetes, and cardiovascular disease in the child. GDM affects approximately 16.5% of pregnancies worldwide, and this number is set to increase with the escalating obesity epidemic. While several management strategies exist-including insulin and lifestyle interventions-there is not yet a cure or an efficacious prevention strategy. One reason for this is that the molecular mechanisms underlying GDM are poorly defined. This review discusses what is known about the pathophysiology of GDM, and where there are gaps in the literature that warrant further exploration.

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.

Programmed for sex: Nutrition–reproduction relationships from an inter-generational perspective

Reproduction is our biological reason for being. Our physiology has been shaped via countless millennia of evolution with this one purpose in mind, so that at birth we are ‘programmed for sex’, although this will not kick-start functionally until puberty. Our development from an early embryo is focused on making us fit to reproduce and is intimately connected to nutrition and energy stores. Fluctuations in food supply has probably been a key evolutionary shaper of the reproductive process, and this review hypothesizes that we have developed rapid, non-genomic adaptive mechanisms to such fluctuations to better fit offspring to their perceived (nutritional) environment, thus giving them a reproductive advantage. There is abundant evidence for this notion from ‘fetal programming’ studies and from experimental ‘inter-generational’ studies involving manipulation of parental (especially paternal) diet and then examining metabolic changes in resulting offspring. It is argued that the epigenetic reprogramming of germ cells that occurs during fetal life, after fertilisation and during gametogenesis provides opportunities for sensing of the (nutritional) environment so as to affect adaptive epigenetic changes to alter offspring metabolic function. In this regard, there may be adverse effects of a modern Western diet, perhaps because it is deficient in plant-derived factors that are proven to be capable of altering the epigenome, folate being a prime example; we have evolved in tune with such factors. Therefore, parental and even grandparental diets may have consequences for health of future generations, but how important this might be and the precise epigenetic mechanisms involved are unknown.

Effects on metabolic parameters in young rats born with low birth weight after exposure to a mixture of pesticides

Pesticide exposure during fetal life can lead to low birth weight and is commonly observed in reproductive toxicology studies. Associations have also been found in low birth weight babies born from pesticide-exposed gardeners. Since low birth weight is also linked to metabolic disorders, it can be speculated that early life exposure to pesticides could increase the risk of becoming obese or developing diabetes later in life. We have analyzed potential long-term effects of gestational and lactational exposure to a low dose mixture of six pesticides that individually can cause low birth weight: Cyromazine, MCPB, Pirimicarb, Quinoclamine, Thiram, and Ziram. Exposed male offspring, who were smaller than controls, displayed some degree of catch-up growth. Insulin and glucagon regulation was not significantly affected, and analyses of liver and pancreas did not reveal obvious histopathological effects. Efforts towards identifying potential biomarkers of metabolic disease-risk did not result in any strong candidates, albeit leptin levels were altered in exposed animals. In fat tissues, the key genes Lep, Nmb and Nmbr were altered in high dosed offspring, and were differentially expressed between sexes. Our results suggest that early-life exposure to pesticides may contribute to the development of metabolic disorders later in life.

Maternal dietary free or bound fructose diversely influence developmental programming of lipogenesis

Background

Maternal dietary choices throughout preconception, pregnancy, and lactation irreversibly affect the development of fetal tissues and organs, known as fetal programming. Recommendations tend to emphasize reducing added sugars. However, the impact of maternal dietary free or bound fructose in added sugars on developmental programming of lipogenesis is unknown.

Methods

Virgin Sprague-Dawley rats were randomly divided into five groups. Rats were given feed and plain water (control) or water containing maltodextrin (vehicle), fructose, high-fructose corn syrup (HFCS) containing 55% fructose, sucrose (20% w/v) for 12 weeks before mating and throughout the pregnancy and lactation periods. Body weight, water, and feed intake were measured throughout the study. At the end of the lactation period, blood was drawn to determine the fasting levels of glucose, insulin, triglycerides, and non-esterified fatty acids (NEFA) in blood. Triglycerides and acetyl Co-A Carboxylase-1 (ACC1) levels in livers were analyzed, and insulin resistance was calculated.

Results

The energy intake of dams in the HFCS group was higher than in the fructose group, while weight gain was less in the HFCS group than in the fructose group. HFCS resulted in greater insulin resistance in dams, whereas free fructose had a robust effect on the fetal programming of insulin resistance. Free fructose and HFCS in the maternal diet increased blood and liver triglycerides and NEFA content in pups. Furthermore, fructose and HFCS exposure increased phosphorylated ACC1 as compared to maltodextrin and control, indicating greater fatty acid synthesis in pups and dams.

Conclusion

Different types of added sugar in the maternal diet have different metabolic effects on the developmental programming of lipogenesis. Consequently, high fructose intake via processed foods may increase the risk for chronic diseases, and free fructose might contribute to developmental programming of chronic diseases more than bound fructose.

Prenatal Dexamethasone Exposure Programs the Development of the Pancreas and the Secretion of Insulin in Rats

BACKGROUND

There is increasing epidemiological evidence indicating that many chronic diseases originate during early life, even before birth, through what are termed fetal programming effects. Prenatal glucocorticoid is frequently used clinically to accelerate the maturation of the lung, but its long-term effects remain unclear.

METHODS

We gave pregnant Sprague-Dawley rats either intraperitoneal dexamethasone (0.1 mg/kg body weight) or vehicle at Gestational Days 14-20 and assessed the effects to pancreas at Postnatal Days 7 and 120.

RESULTS

We found fewer pancreatic β cell fractions (0.31±0.05 % vs. 0.49±0.05 %, p=0.013) and tissues (0.0017±0.0002 % vs. 0.0025±0.0002 %, p=0.042) and decreased secretion of insulin in response to a glucose challenge at Postnatal Day 105 (1.00±0.19 ng/mL vs. 1.57±0.17 ng/mL at the 15-minute time-point, p=0.046) in rats treated prenatally with dexamethasone. At Postnatal Day 7 in rats treated prenatally with dexamethasone, the expression of pancreatic duodenal homeobox gene-1 and V-maf avian musculoaponeurotic fibrosarcoma oncogene homolog A was lower than that in the rats in the Vehicle group (0.22±0.07 vs. 1.00±0.41 fold, p=0.01, 0.20±0.12 vs. 1.00±0.35 fold, p=0.01) while the histone deacetylases activity (54.2±3.7 ng/h/mL vs. 37.6±3.5 ng/h/mL, p=0.012) and 8-hydroxy-2-deoxyguanosine staining (1.34±0.01 vs. 1.00±0.02 fold, p<0.01) were higher.

CONCLUSION

Prenatal dexamethasone exposure affects early postnatal gene expression related to pancreas development and may exert an effect on β-cell development at 120 postnatal days.

Role of nutrients and mTOR signaling in the regulation of pancreatic progenitors development

OBJECTIVE

Poor fetal nutrition increases the risk of type 2 diabetes in the offspring at least in part by reduced embryonic β-cell growth and impaired function. However, it is not entirely clear how fetal nutrients and growth factors impact β-cells during development to alter glucose homeostasis and metabolism later in life. The current experiments aimed to test the impact of fetal nutrients and growth factors on endocrine development and how these signals acting on mTOR signaling regulate β-cell mass and glucose homeostasis.

METHOD

Pancreatic rudiments in culture were used to study the role of glucose, growth factors, and amino acids on β-cell development. The number and proliferation of pancreatic and endocrine progenitor were assessed in the presence or absence of rapamycin. The impact of mTOR signaling in vivo on pancreas development and glucose homeostasis was assessed in models deficient for mTOR or Raptor in Pdx1 expressing pancreatic progenitors.

RESULTS

We found that amino acid concentrations, and leucine in particular, enhance the number of pancreatic and endocrine progenitors and are essential for growth factor induced proliferation. Rapamycin, an mTORC1 complex inhibitor, reduced the number and proliferation of pancreatic and endocrine progenitors. Mice lacking mTOR in pancreatic progenitors exhibited hyperglycemia in neonates, hypoinsulinemia and pancreatic agenesis/hypoplasia with pancreas rudiments containing ductal structures lacking differentiated acinar and endocrine cells. In addition, loss of mTORC1 by deletion of raptor in pancreatic progenitors reduced pancreas size with reduced number of β-cells.

CONCLUSION

Together, these results suggest that amino acids concentrations and in particular leucine modulates growth responses of pancreatic and endocrine progenitors and that mTOR signaling is critical for these responses. Inactivation of mTOR and raptor in pancreatic progenitors suggested that alterations in some of the components of this pathway during development could be a cause of pancreatic agenesis/hypoplasia and hyperglycemia.

Hypothyroidism in utero stimulates pancreatic beta cell proliferation and hyperinsulinaemia in the ovine fetus during late gestation

Key points

Thyroid hormones are important regulators of growth and maturation before birth, although the extent to which their actions are mediated by insulin and the development of pancreatic beta cell mass is unknown.

Hypothyroidism in fetal sheep induced by removal of the thyroid gland caused asymmetric organ growth, increased pancreatic beta cell mass and proliferation, and was associated with increased circulating concentrations of insulin and leptin.

In isolated fetal sheep islets studied in vitro, thyroid hormones inhibited beta cell proliferation in a dose‐dependent manner, while high concentrations of insulin and leptin stimulated proliferation.

The developing pancreatic beta cell is therefore sensitive to thyroid hormone, insulin and leptin before birth, with possible consequences for pancreatic function in fetal and later life.

The findings of this study highlight the importance of thyroid hormones during pregnancy for normal development of the fetal pancreas.

Abstract

Development of pancreatic beta cell mass before birth is essential for normal growth of the fetus and for long‐term control of carbohydrate metabolism in postnatal life. Thyroid hormones are also important regulators of fetal growth, and the present study tested the hypotheses that thyroid hormones promote beta cell proliferation in the fetal ovine pancreatic islets, and that growth retardation in hypothyroid fetal sheep is associated with reductions in pancreatic beta cell mass and circulating insulin concentration in utero. Organ growth and pancreatic islet cell proliferation and mass were examined in sheep fetuses following removal of the thyroid gland in utero. The effects of triiodothyronine (T₃), insulin and leptin on beta cell proliferation rates were determined in isolated fetal ovine pancreatic islets in vitro. Hypothyroidism in the sheep fetus resulted in an asymmetric pattern of organ growth, pancreatic beta cell hyperplasia, and elevated plasma insulin and leptin concentrations. In pancreatic islets isolated from intact fetal sheep, beta cell proliferation in vitro was reduced by T₃ in a dose‐dependent manner and increased by insulin at high concentrations only. Leptin induced a bimodal response whereby beta cell proliferation was suppressed at the lowest, and increased at the highest, concentrations. Therefore, proliferation of beta cells isolated from the ovine fetal pancreas is sensitive to physiological concentrations of T₃, insulin and leptin. Alterations in these hormones may be responsible for the increased beta cell proliferation and mass observed in the hypothyroid sheep fetus and may have consequences for pancreatic function in later life.

Thyroid hormones are important regulators of growth and maturation before birth, although the extent to which their actions are mediated by insulin and the development of pancreatic beta cell mass is unknown.

Hypothyroidism in fetal sheep induced by removal of the thyroid gland caused asymmetric organ growth, increased pancreatic beta cell mass and proliferation, and was associated with increased circulating concentrations of insulin and leptin.

In isolated fetal sheep islets studied in vitro, thyroid hormones inhibited beta cell proliferation in a dose‐dependent manner, while high concentrations of insulin and leptin stimulated proliferation.

The developing pancreatic beta cell is therefore sensitive to thyroid hormone, insulin and leptin before birth, with possible consequences for pancreatic function in fetal and later life.

The findings of this study highlight the importance of thyroid hormones during pregnancy for normal development of the fetal pancreas.

Early-Life Nutritional Programming of Type 2 Diabetes: Experimental and Quasi-Experimental Evidence

Consistent evidence from both experimental and human studies suggest that inadequate nutrition in early life can contribute to risk of developing metabolic disorders including type 2 diabetes (T2D) in adult life. In human populations, most findings supporting a causative relationship between early-life malnutrition and subsequent risk of T2D were obtained from quasi-experimental studies (‘natural experiments’). Prenatal and/or early postnatal exposures to famine were demonstrated to be associated with higher risk of T2D in many cohorts around the world. Recent studies have highlighted the importance of epigenetic regulation of gene expression as a possible major contributor to the link between the early-life famine exposure and T2D in adulthood. Findings from these studies suggest that prenatal exposure to the famine may result in induction of persistent epigenetic changes that have adaptive significance in postnatal development but can predispose to metabolic disorders including T2D at the late stages of life. In this review, quasi-experimental data on the developmental programming of T2D are summarized and recent research findings on changes in DNA methylation that mediate these effects are discussed.

Restricted nutrition-induced low birth weight, low number of nephrons and glomerular mesangium injury in Japanese quail

Insufficient nutrition during the perinatal period causes structural alterations in humans and experimental animals, leading to increased vulnerability to diseases in later life. Japanese quail, Coturnix japonica, in which partial (8-10%) egg white was withdrawn (EwW) from eggs before incubation had lower birth weights than controls (CTs). EwW birds also had reduced hatching rates, smaller glomeruli and lower embryo weight. In EwW embryos, the surface condensate area containing mesenchymal cells was larger, suggesting that delayed but active nephrogenesis takes place. In mature EwW quail, the number of glomeruli in the cortical region (mm2) was significantly lower (CT 34.7±1.4, EwW 21.0±1.2); capillary loops showed focal ballooning, and mesangial areas were distinctly expanded. Immunoreactive cell junction proteins, N-cadherin and podocin, and slit diaphragms were clearly seen. With aging, the mesangial area and glomerular size continued to increase and were significantly larger in EwW quail, suggesting compensatory hypertrophy. Furthermore, apoptosis measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling analysis was higher in EwWs than in CTs on embryonic day 15 and postnatal day 4 (D4). Similarly, plasma glucocorticoid (corticosterone) was higher (P<0.01) on D4 in EwW quail. These results suggest that although nephrogenic activity is high in low-nutrition quail during the perinatal period, delayed development and increased apoptosis may result in a lower number of mature nephrons. Damaged or incompletely mature mesangium may trigger glomerular injury, leading in later life to nephrosclerosis. The present study shows that birds serve as a model for 'fetal programming,' which appears to have evolved phylogenetically early.

Differentiation of Diabetes by Pathophysiology, Natural History, and Prognosis

The American Diabetes Association, JDRF, the European Association for the Study of Diabetes, and the American Association of Clinical Endocrinologists convened a research symposium, "The Differentiation of Diabetes by Pathophysiology, Natural History and Prognosis" on 10-12 October 2015. International experts in genetics, immunology, metabolism, endocrinology, and systems biology discussed genetic and environmental determinants of type 1 and type 2 diabetes risk and progression, as well as complications. The participants debated how to determine appropriate therapeutic approaches based on disease pathophysiology and stage and defined remaining research gaps hindering a personalized medical approach for diabetes to drive the field to address these gaps. The authors recommend a structure for data stratification to define the phenotypes and genotypes of subtypes of diabetes that will facilitate individualized treatment.

The Elevated Susceptibility to Diabetes in India: An Evolutionary Perspective

India has rapidly become a "diabetes capital" of the world, despite maintaining high rates of under-nutrition. Indians develop diabetes at younger age and at lower body weights than other populations. Here, we interpret these characteristics in terms of a "capacity-load" model of glucose homeostasis. Specifically, we assume that glycemic control depends on whether the body's "metabolic capacity," referring to traits, such as pancreatic insulin production and muscle glucose clearance, is able to resolve the "metabolic load" generated by high levels of body fat, high dietary glycemic load, and sedentary behavior. We employ data from modern cohorts to support the model and the interpretation that elevated diabetic risk among Indian populations results from the high metabolic load imposed by westernized lifestyles acting on a baseline of low metabolic capacity. We attribute this low metabolic capacity to the low birth weight characteristic of Indian populations, which is associated with short stature and low lean mass in adult life. Using stature as a marker of metabolic capacity, we review archeological and historical evidence to highlight long-term declines in Indian stature associated with adaptation to several ecological stresses. Underlying causes may include increasing population density following the emergence of agriculture, the spread of vegetarian diets, regular famines induced by monsoon failure, and the undermining of agricultural security during the colonial period. The reduced growth and thin physique that characterize Indian populations elevate susceptibility to truncal obesity, and increase the metabolic penalties arising from sedentary behavior and high glycemic diets. Improving metabolic capacity may require multiple generations; in the meantime, efforts to reduce the metabolic load will help ameliorate the situation.

Day-restricted feeding during pregnancy and lactation programs glucose intolerance and impaired insulin secretion in male rat offspring

AIM

The maternal environment during pregnancy and lactation plays a determining role in programming energy metabolism in offspring. Among a myriad of maternal factors, disruptions in the light/dark cycle during pregnancy can program glucose intolerance in offspring. Out-of-phase feeding has recently been reported to influence metabolism in adult humans and rodents; however, it is not known whether this environmental factor impacts offspring metabolism when applied during pregnancy and lactation. This study aims to determine whether maternal day-restricted feeding (DF) influences energy metabolism in offspring.

METHODS

Pregnant and lactating Wistar rats were subjected to ad libitum (AL) or DF during pregnancy and lactation. The offspring born to the AL and DF dams were intra- and interfostered, which resulted in 4 group types.

RESULTS

The male offspring born to and breastfed by the DF dams (DF/DF off) were glucose intolerant, but without parallel insulin resistance as adults. Experiments with isolated pancreatic islets demonstrated that the male DF/DF off rats had reduced insulin secretion with no parallel disruption in calcium handling. However, this reduction in insulin secretion was accompanied by increased miRNA-29a and miRNA34a expression and decreased syntaxin 1a protein levels.

CONCLUSION

We conclude that out-of-phase feeding during pregnancy and lactation can lead to glucose intolerance in male offspring, which is caused by a disruption in insulin secretion capacity. This metabolic programming is possibly caused by mechanisms dependent on miRNA modulation of syntaxin 1a.

Food contaminants and programming of type 2 diabetes: recent findings from animal studies

It is now accepted that the way our health evolves with aging is intimately linked to the quality of our early life. The present review highlights the emerging data of Developmental Origins of Health and Disease field on developmental disruption by toxicants and their subsequent effect on type 2 diabetes. We report adverse neonatal effects of several food contaminants during pregnancy and lactation, among them bisphenol A, chlorpyrifos, perfluorinated chemicals on pancreas integrity and functionality in later life. The described alterations, in conjunction with disruption of β cell mass in early life, can lead to dysregulation of glucose metabolism, insulin synthesis, which facilitates the development of insulin resistance and progression of diabetes in the adult. Despite limited and often inconclusive epidemiologic and experimental data, more recent data clearly show that infants appear to be at increased risk of type 2 diabetes in later life. This may be a result of continued exposure to chemical food contaminants during the critical window of pancreas development. In societies already burdened with increased incidence of non-communicable chronic diseases, there is a clear need for information regarding the potential harmful effects of chemical food contaminants on adult health diseases.

Management of Pregnant Women with Type 2 Diabetes Mellitus and the Consequences of Fetal Programming in Their Offspring

The obesity epidemic has fueled an epidemic of prediabetes and type 2 diabetes mellitus in women of childbearing age. This paper examines the state of the science on preconception and pregnancy management of women with type 2 diabetes to optimize outcomes for the women and their infants. In addition, the consequence of fetal programming as a result of suboptimal maternal glycemic control is discussed. The paper focuses on type 2 diabetes, not type 1 diabetes or gestational diabetes. Management of women with type 2 diabetes includes preconception counseling, preconception weight management and weight loss, proper weight gain during pregnancy, self-monitoring of blood glucose levels, medication, medical nutrition therapy, and exercise.

Maternal protein restriction during gestation impairs female offspring pancreas development in the rat

A maternal low-protein (LP) diet programs fetal pancreatic islet β-cell development and function and predisposes offspring to metabolic dysfunction later in life. We hypothesized that maternal protein restriction during pregnancy differentially alters β- and α-cell populations in offspring by modifying islet ontogeny and function throughout life. We aimed to investigate the effect of an LP maternal diet on pancreatic islet morphology and cellular composition in female offspring on postnatal days (PNDs) 7, 14, 21, 36, and 110. Mothers were divided into 2 groups: during pregnancy, the control group (C) was fed a diet containing 20% casein, and the LP group was fed an isocaloric diet with 10% casein. Offspring pancreases were obtained at each PND and then processed. β and α cells were detected by immunohistochemistry, and cellular area and islet size were quantified. Islet cytoarchitecture and total area were similar in C and LP offspring at all ages studied. At the early ages (PNDs 7-21), the proportion of β cells was lower in LP than C offspring. The proportion of α cells was lower in LP than C offspring on PND 14 and higher on PND 21. The β/α-cell ratio was lower in LP compared with C offspring on PNDs 7 and 21 and higher on PND 36 (being similar on PNDs 14 and 110). We concluded that maternal protein restriction during pregnancy modifies offspring islet cell ontogeny by altering the proportions of islet sizes and by reducing the number of β cells postnatally, which may impact pancreatic function in adult life.

Fetal programming and gestational diabetes mellitus

Gestational diabetes mellitus is defined by new-onset glucose intolerance during pregnancy. About 2-5% of all pregnant women develop gestational diabetes during their pregnancies and the prevalence has increased considerably during the last decade. This metabolic condition is manifested when pancreatic β-cells lose their ability to compensate for increased insulin resistance during pregnancy, however, the pathogenesis of the disease remains largely unknown. Gestational diabetes is strongly associated with adverse pregnancy outcome as well as with long-term adverse effects on the offspring which likely occurs due to epigenetic modifications of the fetal genome. In the current review we address gestational diabetes and the short and long term complications for both mothers and offspring focusing on the importance of fetal programming in conferring risk of developing diseases in adulthood.