Intrauterine exposure to hyperglycemia retards the development of brown adipose tissue

Intrauterine hyperglycaemia during late gestation caused mitochondrial dysfunction in skeletal muscle of male offspring through CREB/PGC1A signaling

BACKGROUND

Maternal diabetes mellitus can influence the development of offspring. Gestational diabetes mellitus (GDM) creates a short-term intrauterine hyperglycaemic environment in offspring, leading to glucose intolerance in later life, but the long-term effects and specific mechanism involved in skeletal muscle dysfunction in offspring remain to be clarified.

METHODS

Pregnant mice were divided into two groups: The GDM group was intraperitoneally injected with 100 mg/kg streptozotocin on gestational days (GDs) 6.5 and 12.5, while the control (CTR) group was treated with vehicle buffer. Only pregnant mice whose random blood glucose level was higher than 16.8 mmol/L beginning on GD13.5 were regarded as the GDM group. The growth of the offspring was monitored, and the glucose tolerance test was performed at different time points. Body composition analysis and immunohistochemical methods were used to evaluate the development of lean mass at 8 weeks. The exercise capacity and grip strength of the male mouse offspring were assessed at the same period. Transmission electron microscopy was used to observe the morphology inside skeletal muscle at 8 weeks and as a foetus. The genes and proteins associated with mitochondrial biogenesis and oxidative metabolism were investigated. We also coanalyzed RNA sequencing and proteomics data to explore the underlying mechanism. Chromatin immunoprecipitation and bisulfite-converted DNA methylation detection were performed to evaluate this phenomenon.

RESULTS

Short-term intrauterine hyperglycaemia inhibited the growth and reduced the lean mass of male offspring, leading to decreased endurance exercise capacity. The myofiber composition of the tibialis anterior muscle of GDM male offspring became more glycolytic and less oxidative. The morphology and function of mitochondria in the skeletal muscle of GDM male offspring were destroyed, and coanalysis of RNA sequencing and proteomics of foetal skeletal muscle showed that mitochondrial elements and lipid oxidation were consistently impaired. In vivo and in vitro myoblast experiments also demonstrated that high glucose concentrations impeded mitochondrial organisation and function. Importantly, the transcription of genes associated with mitochondrial biogenesis and oxidative metabolism decreased at 8 weeks and during the foetal period. We predicted Ppargc1α as a key upstream regulator with the help of IPA software. The proteins and mRNA levels of Ppargc1α in the skeletal muscle of GDM male offspring were decreased as a foetus (CTR vs. GDM, 1.004 vs. 0.665, p = 0.002), at 6 weeks (1.018 vs. 0.511, p = 0.023) and 8 weeks (1.006 vs. 0.596, p = 0.018). In addition, CREB phosphorylation was inhibited in GDM group, with fewer activated pCREB proteins binding to the CRE element of Ppargc1α (1.042 vs. 0.681, p = 0.037), Pck1 (1.091 vs. 0.432, p = 0.014) and G6pc (1.118 vs. 0.472, p = 0.027), resulting in their decreased transcription. Interestingly, we found that sarcopenia and mitochondrial dysfunction could even be inherited by the next generation.

CONCLUSIONS

Short-term intrauterine hyperglycaemia significantly reduced lean mass in male offspring at 8 weeks, resulting in decreased exercise endurance and metabolic disorders. Disrupted organisation and function of the mitochondria in skeletal muscle were also observed among them. Foetal exposure to hyperglycaemia decreased the ratio of phosphorylated CREB and reduced the transcription of Ppargc1α, which inhibited the transcription of downstream genes involving in mitochondrial biogenesis and oxidative metabolism. Abnormal mitochondria, which might be transmitted through aberrant gametes, were also observed in the F2 generation.

Long-term outcomes and potential mechanisms of offspring exposed to intrauterine hyperglycemia

Diabetes mellitus during pregnancy, which can be classified into pregestational diabetes and gestational diabetes, has become much more prevalent worldwide. Maternal diabetes fosters an intrauterine abnormal environment for fetus, which not only influences pregnancy outcomes, but also leads to fetal anomaly and development of diseases in later life, such as metabolic and cardiovascular diseases, neuropsychiatric outcomes, reproduction malformation, and immune dysfunction. The underlying mechanisms are comprehensive and ambiguous, which mainly focus on microbiota, inflammation, reactive oxygen species, cell viability, and epigenetics. This review concluded with the influence of intrauterine hyperglycemia on fetal structure development and organ function on later life and outlined potential mechanisms that underpin the development of diseases in adulthood. Maternal diabetes leaves an effect that continues generations after generations through gametes, thus more attention should be paid to the prevention and treatment of diabetes to rescue the pathological attacks of maternal diabetes from the offspring.

High-fat diet during pregnancy lowers fetal weight and has a long-lasting adverse effect on brown adipose tissue in the offspring

Maternal obesity and malnutrition during gestation and lactation have been recognized to increase the risk of obesity and metabolic disorders in the offspring across their lifespan. However, the gestational period during which malnutrition exerts a decisive effect is unclear. Brown adipose tissue (BAT) plays a critical role in energy metabolism owing to its high efficiency in oxidizing glucose and fatty acids. This study aimed to determine the impact of maternal high-fat diet (HFD) consumption only during pregnancy on BAT and energy metabolism in offspring mice. Dams were fed an HFD or a normal chow diet from embryonic day 2.5. HFD consumption during pregnancy induced glucose intolerance and hypertension in dams. In the offspring of HFD-fed dams, maternal HFD lowered fetal weight without affecting placental weight, whereas HFD consumption after birth exacerbated oxygen consumption and cold-induced thermogenesis at 12 months of age, accompanied by increased lipid droplet size in BAT. These data demonstrate that HFD consumption only during pregnancy exerts a long-lasting effect on BAT. Collectively, these findings indicate the importance of nutrition during pregnancy with respect to the energy metabolism of the offspring, and pregnant women should thus ensure proper nutrition during pregnancy to ensure normal energy metabolism in the offspring.

Predictive plasma biomarker for gestational diabetes: A case-control study in China

OBJECTIVE

This study aims to find new plasma biomarkers in early pregnancy.

DESIGN

The original study enrolled 1219 pregnant women. We investigated protein expression profiles of placental tissues from women with GDM (n = 89) and normal glucose tolerance (NGT) (n = 83). Maternal plasma samples between two groups in early and middle pregnancy were used for validation of candidate biomarkers.

METHODS

Differentially expressed proteins (DEPs) were identified by label-free quantitative proteomics from human placenta samples between two groups. Several DEPs were validated in plasma by Luminex assays. An automatic biochemical analyzer was used to detect blood lipid indexes. The associations of GAL-3BP with biochemical indicators were demonstrated by Pearson's correlation analysis. Binary logistic regression was used to model potential predictive indicators in early pregnancy of GDM. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy of the predictive model and the value of GAL-3BP.

RESULTS

123 DEPs were found in placenta involved in ribosomal function, pancreatic secretion, oxidative phosphorylation, and inflammatory signaling pathway. Plasma GAL-3BP are significantly higher in women with GDM than NGT in the first (p = 0.008) and second (p = 0.026) trimester, but C9 and VWF have no difference. The predictive value of GAL-3BP in the first trimester of pregnancy (AUC 0.64) is better than that in the second trimester (AUC 0.61), and combined predictive model of TG and GAL-3BP at early pregnancy has greater predictive and diagnostic value for GDM (AUC 0.69) than individual GAL-3BP (AUC 0.64).

CONCLUSIONS

Plasma TG and GAL-3BP has good predictive and diagnostic value at early pregnancy, suggesting that these two indicators may be used as biomarkers for early prediction and diagnosis of GDM.

SIGNIFICANCE

The advantage of this study is that circulating TG and GAL-3BP might differentiate the progress of women with GDM and normal glucose tolerance (NGT) at the early stage of pregnancy. It is the first study to consider the role of GAL-3BP as an early predictive biomarker in the development of GDM during the whole pregnancy. Another advantage is that volunteers in this study were recruited from two provinces in China to eliminate the impacts of environmental confounders. The similar changes of blood glucose/lipid indicators for women with GDM and NGT in both regions was found in the first and second trimester of pregnancy, which added to the reliability of analytical results.

Effect of Corn Silk Aqueous Extract on Brown Adipose Tissue of Embryos and Neonates of Diabetic Pregnant Mice: A Histological Study

Context

Many congenital malformations are seen increasingly, due to diabetic mothers causing a burden on health systems. Corn silk (CS) extract has been used as a natural hypoglycemic treatment. However, its teratogenic safety was not studied.

Aims

Therefore, in this study, we examine the effect of CS aqueous extract on fetuses, offspring of normal and diabetic female mice treated with CS aqueous extract.

Settings and Design

Pregnant female mice were divided into two groups diabetic and nondiabetic. Then, each of these groups was divided into control and treated.

Subjects and Methods

A daily dose of 4 g/kg of CS aqueous extract was given orally to the treated groups, control groups were given distilled water. The collection of samples was at day 16.5 of pregnancy, and neonates. Brown adipose tissue (BAT) in the sections of the preserved sample was examined.

Statistical Analysis Used

BAT areas were measured from 10 samples of each treatment age group in 2 sections. Data were analyzed with one-way ANOVA, then, two-independent sample test (Mann-Whitney) was done to test the significance of differences between groups.

Results

The BAT areas were negatively affected by diabetes and the extract. Both the extract and diabetes caused an increase in fat accumulation in the adipocytes with varying degrees.

Conclusions

This study showed for the first time to our knowledge that the use of CS aqueous extract during pregnancy affected BAT organization and area, and that the used dose did not decrease the malformations caused by diabetes. More studies with different doses should be investigated.

Glycemic control and neonatal outcomes in women with gestational diabetes mellitus treated using glyburide, metformin, or insulin: a pairwise and network meta-analysis

AIMS

We aimed to assess the comparative efficiency and safety of the use of glyburide, metformin, and insulin in gestational diabetes mellitus (GDM).

METHODS

We searched for randomized controlled trials that compared glyburide, metformin, and insulin in GDM. Data regarding glycemic control and neonatal safety were collected and analyzed in pairwise and network meta-analyses.

RESULTS

A total of 4533 individuals from 23 trials were included. Compared with glyburide, metformin reduced 2-h postprandial blood glucose (2HPG) to a greater extent (standard mean difference (SMD) 0.18; 95% credible interval (CI) 0.01, 0.34). There were significantly lower prevalence of neonatal hypoglycemia (risk difference (RD) - 0.07; 95%CI - 0.11, - 0.02) and preeclampsia (RD - 0.03; 95%CI - 0.06, 0) in the metformin group than in the insulin group. The metformin group had significantly lower birth weight (SMD - 0.17; 95%CI - 0.25, - 0.08) and maternal weight gain (SMD - 0.61; 95%CI - 0.86,- 0.35) compared with the insulin group. Network meta-analysis suggested that metformin had the highest probability of successfully controlling glycemia and preventing neonatal complications.

CONCLUSIONS

The present meta-analysis suggests that metformin may be as effective as insulin for glycemic control and is the most promising drug for the prevention of neonatal and maternal complications.

Vignacyanidin Polyphenols Isolated from Vigna Angularis Bean Promote Osteoblast Differentiation

BACKGROUND/AIM

An effective bone regenerative method needs to be established for the dental field. To identify a novel osteogenic factor for bone regeneration, we examined the effect of vignacyanidin (VIG) on osteoblastogenesis.

MATERIALS AND METHODS

W20-17 cells, MC3T3-E1 cells, and primary cultured murine calvarial osteoblasts were used. Osteoblast differentiation was stimulated by β-glycerophosphate, ascorbic acid, or bone morphogenetic protein (BMP)-4. Adipogenesis was induced using dexamethasone, 3-isobutyl-1-methylxanthine, insulin, and rosiglitazone. Differentiation or proliferation markers were determined using western blotting and/or the quantitative reverse transcription polymerase chain reaction. Adipogenic cells were visualized by Oil Red O staining.

RESULTS

VIG treatment increased the expression of osteoblastic markers and alkaline phosphatase activity of osteoblast-lineage cells in a concentration-dependent manner. However, adipogenesis and cell proliferation were not affected by VIG.

CONCLUSION

VIG treatment promoted osteoblast differentiation in osteoblast-lineage cells.

Gestational Diabetes Mellitus and Developmental Programming

During normal pregnancy, increased insulin resistance acts as an adaptation to enhance materno-foetal nutrient transfer and meet the nutritional needs of the developing foetus, particularly in relation to glucose requirements. However, about 1 in 6 pregnancies worldwide is affected by the inability of the mother's metabolism to maintain normoglycaemia, with the combination of insulin resistance and insufficient insulin secretion resulting in gestational diabetes mellitus (GDM). A growing body of epidemiologic work demonstrates long-term implications for adverse offspring health resulting from exposure to GDM in utero. The effect of GDM on offspring obesity and cardiometabolic health may be partly influenced by maternal obesity; this suggests that improving glucose and weight control during early pregnancy, or better still before conception, has the potential to lessen the risk to the offspring. The consequences of GDM for microbiome modification in the offspring and the impact upon offspring immune dysregulation are actively developing research areas. Some studies have suggested that GDM impacts offspring neurodevelopmental and cognitive outcomes; confirmatory studies will need to separate the effect of GDM exposure from the complex interplay of social and environmental factors. Animal and human studies have demonstrated the role of epigenetic modifications in underpinning the predisposition to adverse health in offspring exposed to suboptimal hyperglycaemic in utero environment. To date, several epigenome-wide association studies in human have extended our knowledge on linking maternal diabetes-related DNA methylation marks with childhood adiposity-related outcomes. Identification of such epigenetic marks can help guide future research to develop candidate diagnostic biomarkers and preventive or therapeutic strategies. Longer-term interventions and longitudinal studies will be needed to better understand the causality, underlying mechanisms, or impact of GDM treatments to optimize the health of future generations.

Maternal Roux-en-Y gastric bypass surgery reduces lipid deposition and increases UCP1 expression in the brown adipose tissue of male offspring

Maternal obesity induced by cafeteria diet (CAF) predisposes offspring to obesity and metabolic diseases, events that could be avoided by maternal bariatric surgery (BS). Herein we evaluated whether maternal BS is able to modulate brown adipose tissue (BAT) morphology and function in adult male rats born from obese female rats submitted to Roux-en-Y gastric bypass (RYGB). For this, adult male rat offspring were obtained from female rats that consumed standard diet (CTL), or CAF diet, and were submitted to simulated operation or RYGB. Analysis of offspring showed that, at 120 days of life, the maternal CAF diet induced adiposity and decreased the expression of mitochondrial Complex I (CI) and Complex III (CIII) in the BAT, resulting in higher accumulation of lipids than in BAT from offspring of CTL dams. Moreover, maternal RYGB increased UCP1 expression and prevented excessive deposition of lipids in the BAT of adult male offspring rats. However, maternal RYGB failed to reverse the effects of maternal diet on CI and CIII expression. Thus, maternal CAF promotes higher lipid deposition in the BAT of offspring, contributing to elevated adiposity. Maternal RYGB prevented obesity in offspring, probably by increasing the expression of UCP1.

Maternal High-Fat Diet Disturbs the DNA Methylation Profile in the Brown Adipose Tissue of Offspring Mice

The prevalence of obesity has become a threatening global public health issue. The consequence of obesity is abnormal energy metabolism. Unlike white adipose tissue (WAT), brown adipose tissue (BAT) has a unique role in nonshivering thermogenesis. Lipids and glucose are consumed to maintain energy and metabolic homeostasis in BAT. Recently, accumulating evidence has indicated that exposure to excess maternal energy intake affects energy metabolism in offspring throughout their life. However, whether excess intrauterine energy intake influences BAT metabolism in adulthood is not clear. In this study, mouse dams were exposed to excess energy intake by feeding a high-fat diet (HFD) before and during pregnancy and lactation. The histology of BAT was assessed by hematoxylin and eosin staining. The genome-wide methylation profile of BAT was determined by a DNA methylation array, and specific site DNA methylation was quantitatively analyzed by methylated DNA immunoprecipitation (MeDIP) qPCR. We found that intrauterine exposure to a high-energy diet resulted in blood lipid panel disorders and impaired the BAT structure. Higher methylation levels of genes involved in thermogenesis and fatty acid oxidation (FAO) in BAT, such as Acaa2, Acsl1, and Cox7a1, were found in 16-week-old offspring from mothers fed with HFD. Furthermore, the expression of Acaa2, Acsl1, and Cox7a1 was down-regulated by intrauterine exposure to excess energy intake. In summary, our results reveal that excess maternal energy leads to a long-term disorder of BAT in offspring that involves the activation of DNA methylation of BAT-specific genes involved in fatty acid oxidation and thermogenesis.

Relationship of prenatal maternal obesity and diabetes to offspring neurodevelopmental and psychiatric disorders: a narrative review

Obesity and diabetes is a worldwide public health problem among women of reproductive age. This narrative review highlights recent epidemiological studies regarding associations of maternal obesity and diabetes with neurodevelopmental and psychiatric disorders in offspring, and provides an overview of plausible underlying mechanisms and challenges for future human studies. A comprehensive search strategy selected terms that corresponded to the domains of interest (maternal obesity, different types of diabetes, offspring cognitive functions and neuropsychiatric disorders). The databases searched for articles published between January 2010 and April 2019 were PubMed, Web of Science and CINAHL. Evidence from epidemiological studies strongly suggests that maternal pre-pregnancy obesity is associated with increased risks for autism spectrum disorder, attention-deficit hyperactivity disorder and cognitive dysfunction with modest effect sizes, and that maternal diabetes is associated with the risk of the former two disorders. The influence of maternal obesity on other psychiatric disorders is less well studied, but there are reports of associations with increased risks for offspring depression, anxiety, schizophrenia and eating disorders, at modest effect sizes. It remains unclear whether these associations are due to intrauterine mechanisms or explained by confounding family-based sociodemographic, lifestyle and genetic factors. The plausible underlying mechanisms have been explored primarily in animal models, and are yet to be further investigated in human studies.

Alternative Polyadenylation and Differential Regulation of Ucp1: Implications for Brown Adipose Tissue Thermogenesis Across Species

Brown adipose tissue (BAT) is a thermogenic organ owing to its unique expression of uncoupling protein 1 (UCP1), which is a proton channel in the inner mitochondrial membrane used to dissipate the proton gradient and uncouple the electron transport chain to generate heat instead of adenosine triphosphate. The discovery of metabolically active BAT in human adults, especially in lean people after cold exposure, has provoked the "thermogenic anti-obesity" idea to battle weight gain. Because BAT can expend energy through UCP1-mediated thermogenesis, the molecular mechanisms regulating UCP1 expression have been extensively investigated at both transcriptional and posttranscriptional levels. Of note, the 3'-untranslated region (3'-UTR) of Ucp1 mRNA is differentially processed between mice and humans that quantitatively affects UCP1 synthesis and thermogenesis. Here, we summarize the regulatory mechanisms underlying UCP1 expression, report the number of poly(A) signals identified or predicted in Ucp1 genes across species, and discuss the potential and caution in targeting UCP1 for enhancing thermogenesis and metabolic fitness.

Maternal metabolic syndrome and selenium: Endocrine energy balance during early programming

BACKGROUND

Maternal metabolic syndrome during gestation and lactation leads to several Se-status-related metabolic changes in offspring. MS leads to hepatomegaly, liver oxidation, resistance to insulin challenges and selenoptroteins expression upregulation, producing an energy imbalance in hepatocytes. As Se is necessary for correct heart function, Se deposits are depleted and selenoproteins expression downregulated in heart; this depletion being related to cardiovascular damage. Recently, selenoproteins have been directly implicated in the central endocrine regulation of appetite and energy homeostasis.

METHODS

To obtain information about how Se is involved in regulating endocrine peripheral energy balance during MS process, two experimental groups of dam rats were used: control (Se: 0.1 ppm) and MS (Fructose 65% and Se: 0.1 ppm). At the end of lactation (21d old), the pups' appetite profile, tissular Se deposits and peptides from gastrointestinal tract (including pancreas), leptin, skeletal growth markers and cytokines in serum were measured.

RESULTS

MS-exposed pups present changes in Se homeostasis, appetite profile and endocrine energy balance signals related to impaired insulin secretion and high leptin serum values. This profoundly affects the pups' growth profile since muscle and bones are in catabolic process and brown adipose tissue (BAT) mass decreases.

CONCLUSION

These results indicate that the pups are suffering a process similar to diabetes type 1 which appeared when dams received low Se dietary supply and they point to Se as an important marker and key treatment for these disorders during gestation and lactation that affect future adult health.