Prenatal food restriction induces a hypothalamic-pituitary-adrenocortical axis-associated neuroendocrine metabolic programmed alteration in adult offspring rats

Early life nutrient restriction affects hypothalamic-pituitary-interrenal axis gene expression in a diet type-specific manner

Stressful experiences in early life can alter phenotypic expression later in life. For instance, in vertebrates, early life nutrient restriction can modify later life activity of the hypothalamic-pituitary-adrenal/interrenal axis (the HPI in amphibians), including the up- and downstream regulatory components of glucocorticoid signaling. Early life nutrient restriction can also influence later life behavior and metabolism (e.g., fat accumulation). Yet, less is known about whether nutrient stress-induced carryover effects on HPA/HPI axis regulation can vary across environmental contexts, such as the type of diet on which nutrient restriction occurs. Here, we experimentally address this question using the plains spadefoot toad (Spea bombifrons), whose larvae develop in ephemeral habitats that impose intense competition over access to two qualitatively distinct diet types: detritus and live shrimp prey. Consistent with diet type-specific carryover effects of early life nutrient restriction on later life HPI axis regulation, we found that temporary nutrient restriction at the larval stage reduced juvenile (i.e., post-metamorphic) brain gene expression of an upstream glucocorticoid regulator (corticotropin-releasing hormone) and two downstream regulators (glucocorticoid and mineralocorticoid receptors) only on the shrimp diet. These patterns are consistent with known diet type-specific effects of larval nutrient restriction on juvenile corticosterone and behavior. Additionally, larval nutrient restriction increased juvenile body fat levels. Our study indicates that HPA/HPI axis regulatory responses to nutrient restriction can vary remarkably across diet types. Such diet type-specific regulation of the HPA/HPI axis might provide a basis for developmental or evolutionary decoupling of stress-induced carryover effects.

Intrauterine developmental origin, programming mechanism, and prevention strategy of fetal-originated hypercholesterolemia

There is increasing evidence that hypercholesterolemia has an intrauterine developmental origin. However, the pathogenesis of fetal-originated is still lacking in a theoretical system, which makes its clinical early prevention and treatment difficult. It has been found that an adverse environment during pregnancy (e.g., xenobiotic exposure) may lead to changes in fetal blood cholesterol levels through changing maternal cholesterol metabolic function and/or placental cholesterol transport function and may also directly affect the liver cholesterol metabolic function of the offspring in utero and continue after birth. Adverse environmental conditions during pregnancy may also raise maternal glucocorticoid levels and promote the placental glucocorticoid barrier opening, leading to fetal overexposure to maternal glucocorticoids. Intrauterine high-glucocorticoid exposure can alter the liver cholesterol metabolism of offspring, resulting in an increased susceptibility to hypercholesterolemia after birth. Abnormal epigenetic modifications are involved in the intrauterine programming mechanism of fetal-originated hypercholesterolemia. Some interventions targeted at pregnant mothers or offspring in early life have been proposed to effectively prevent and treat the development of fetal-originated hypercholesterolemia. In this paper, the recent research progress on fetal-originated hypercholesterolemia was reviewed, with emphasis on intrauterine maternal glucocorticoid programming mechanisms, in order to provide a theoretical basis for its early clinical warning, prevention, and treatment.

Dysfunction of the hypothalamic‑pituitary‑adrenal axis in male rat offspring with prenatal food restriction: Fetal programming of hypothalamic hyperexcitability and poor hippocampal feedback

Prenatal food restriction (PFR) induces dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis in the adult offspring. The aim of the present study was to identify the underlying mechanism of this process. Pregnant rats were placed on a restricted diet between gestational day 11 and 21. The offspring were fed with a high-fat diet and were subjected to unpredictable chronic stress (UCS) from postnatal week 17 to 20. A higher serum corticosterone (CORT) level was observed in the PFR fetuses. Although lower arginine vasopressin (AVP), hippocampal vesicular glutamate transporter 2 (vGLUT2) and glutamic acid decarboxylase 65 (GAD65) mRNA expression levels were detected in the hippocampi of PFR fetuses, the ratio of the mRNA expression levels of vGLUT2 and GAD65 was higher compared with that of the controls, which was accompanied by histopathological and ultrastructural abnormalities of both the hypothalamus and hippocampus. However, there were no marked changes in the hippocampal expression levels of glucocorticoids receptor (GR) and mineralocorticoids receptor (MR) or the ratio of MR/GR ratio. After the fetuses had matured, lower serum CORT and adrenocorticotropic hormone (ACTH) levels were observed in PFR rats without UCS when compared with the control. A higher rise rate of serum ACTH was also observed after UCS when compared with that in rats without UCS. Furthermore, the hypothalamic mRNA expression level of corticotrophin-releasing hormone (CRH) was lower in PFR rats without UCS, while expression levels of CRH, AVP, GAD65 and vGLUT2 were enhanced after UCS when compared with the control, accompanied by an increased vGLUT2/GAD65 expression ratio. MR mRNA expression was lower, and GR mRNA expression was higher in the hippocampus of the PFR rats without UCS when compared with the control. However, the mRNA expression levels of both MR and GR in the PFR rats were higher compared with those of the control after UCS, which was accompanied histopathological changes in the dentate gyrus, cornu ammonis (CA1) and CA3 areas. In summary, it was suggested that PFR induced fetal alterations of the HPA axis manifesting as hypothalamic hyperexcitability and poor hippocampal feedback, which persisted to adulthood and affected the behavior of the rat offspring.

Sex-dependent effects of prenatal food and protein restriction on offspring physiology in rats and mice: systematic review and meta-analyses

BACKGROUND

Males and females may experience different effects of early-life adversity on life-long health. One hypothesis is that male foetuses invest more in foetal growth and relatively less in placental growth, and that this makes them susceptible to poor nutrition in utero, particularly if nutrition is reduced part-way through gestation.

OBJECTIVES

Our objectives were to examine whether (1) food and/ or protein restriction in rats and mice has consistent sex-dependent effects, (2) sex-dependency differs between types of outcomes, and (3) males are more severely affected when restriction starts part-way through gestation.

DATA SOURCES

PubMed and Web of Science were searched to identify eligible studies.

STUDY ELIGIBILITY CRITERIA

Eligible studies described controlled experiments that restricted protein or food during gestation in rats or mice, examined physiological traits in offspring from manipulated pregnancies, and tested whether effects differed between males and females.

RESULTS

Our search identified 292 articles, of which the full texts of 72 were assessed, and 65 were included for further synthesis. A majority (50) used Wistar or Sprague-Dawley rats and so these were the primary focus. Among studies in which maternal diet was restricted for the duration of gestation, no type of trait was consistently more severely affected in one particular sex, although blood pressure was generally increased in both sexes. Meta-analysis found no difference between sexes in the effect of protein restriction throughout gestation on blood pressure. Among studies restricting food in the latter half of gestation only, there were again few consistent sex-dependent effects, although three studies found blood pressure was increased in males only. Meta-analysis found that food restriction in the second half of gestation increased adult blood pressure in both sexes, with a significantly greater effect in males. Birthweight was consistently reduced in both sexes, a result confirmed by meta-analysis.

CONCLUSIONS

We found little support for the hypotheses that males are more affected by food and protein restriction, or that effects are particularly severe if nutrition is reduced part-way through gestation. However, less than half of the studies tested for sex by maternal diet interactions to identify sex-dependent effects. As a result, many reported sex-specific effects may be false positives.

Prenatal ethanol exposure induced disorder of hypothalamic-pituitary-adrenal axis-associated neuroendocrine metabolic programming alteration and dysfunction of glucose and lipid metabolism in 40-week-old female offspring rats

This study was designed to demonstrate disorder of hypothalamic-pituitary-adrenal (HPA) axis-associated neuroendocrine metabolic programming alteration and dysfunction of glucose and lipid metabolism induced by prenatal ethanol exposure (PEE) in postnatal week 40 (PW40) female offspring rats. Pregnant Wistar rats were administrated 4  g/kg·d ethanol intragastrically from gestational day 11 until term delivery. After weaning, the female offspring were fed with high-fat diet until PW24, and suffered to unpredictable chronic stress (UCS) during PW38-40. Animal serum was collected to examine the changes in hypothalamic-pituitary-adrenal (HPA) axis activity, glucose and lipid metabolic phenotypes before and after UCS. We found that pups in the PEE group manifested a low birthweight at PW1 and an early catch-up growth pattern. Furthermore, a low basal activity of HPA axis continued to PW38 in the PEE group. On the basal condition, serum low-density lipoprotein-cholesterol (LDL-C) level was significantly increased and high-density lipoprotein-cholesterol (HDL-C) level was significantly decreased in the PEE group, while serum triglyceride, total cholesterol (TCH), glucose and insulin levels were not significantly changed. Under unpredictable chronic stress, serum insulin in the PEE group was significantly decreased, while the levels of serum triglyceride, TCH, LDL-C, and the ratio of LDL-C/HDL-C were significantly higher than those in the control. These results suggest that PEE increases the dysfunction of glucose and lipid metabolism in PW40 female offspring, which is related to the disorder of HPA axis-associated neuroendocrine metabolic programming alteration.

Prenatal ethanol exposure enhances the susceptibility to depressive behavior of adult offspring rats fed a high‑fat diet by affecting BDNF‑associated pathway

Epidemiological studies have shown that exposure to ethanol during pregnancy can result in an increased risk for depression in offspring. A 'brain-derived neurotrophic factor (BDNF) hypothesis' has been proposed to help explain the pathogenic mechanism of depression. This study was designed to verify the enhanced susceptibility to depression in prenatal ethanol exposure (PEE) offspring rats and explore possible intrauterine programming mechanisms related to the BDNF signaling pathway. Pregnant rats were intragastrically administrated ethanol (4 g/kg/day) from gestational day 11 until term delivery. All offspring rats were given a high-fat diet after weaning. Then the behavior tests, including sucrose preference test and open field test, were performed to adult offspring rats. The histomorphology of hippocampus was examined, and the expression of genes related to the BDNF signaling pathway was detected in the hippocampus of PEE offspring. The PEE female adult offspring rats showed depression-like behavior, with obvious morphological injury in hippocampus. Additionally, the mRNA expression levels of glucocorticoid receptor (GR) and BDNF pathway-associated genes were changed in hippocampus. Multigene RT-qPCR also revealed that the mRNA expression levels for BDNF pathway-associated genes and synaptic plasticity genes were decreased in the hippocampus of fetal offspring rats in the PEE group. The underlying mechanism involves an increased GR expression that constantly suppresses the BDNF signaling pathway, and aggravates the functional insult to the hippo-campus, resulting in an increased susceptibility to depression among PEE female adult offspring rats. Results of the present study provide theoretical and experimental evidence that can be used for the early prevention and treatment of depression.

The brain development of infants with intrauterine growth restriction: role of glucocorticoids

Brain injury is a serious complication of intrauterine growth restriction (IUGR), but the exact mechanism remains unclear. While glucocorticoids (GCs) play an important role in intrauterine growth and development, GCs also have a damaging effect on microvascular endothelial cells. Moreover, intrauterine adverse environments lead to fetal growth restriction and the hypothalamus-pituitary-adrenal (HPA) axis resetting. In addition, chronic stress can cause a decrease in the number and volume of astrocytes in the hippocampus and glial cells play an important role in neuronal differentiation. Therefore, it is speculated that the effect of GCs on cerebral neurovascular units under chronic intrauterine stimulation is an important mechanism leading to brain injury in infants with growth restrictions.

Prenatal ethanol exposure-induced a low level of foetal blood cholesterol and its mechanism of IGF1-related placental cholesterol transport dysfunction

Clinical researches showed that intrauterine growth retardation (IUGR) foetus had decreased blood cholesterol levels. The present study aimed to confirm that prenatal ethanol exposure (PEE) caused decreased blood cholesterol levels in IUGR foetal rats and elucidate its placental mechanism. Pregnant Wistar rats were intragastrically administrated with ethanol (4 g/kg.d) on gestational days 9-20 (GD9-20). in vivo, PEE increased the levels of total cholesterol (TCH), high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C) in maternal serum, whereas decreased them in both female and male foetal serum. Moreover, the expression of cholesterol transport genes, scavenger receptor class B type 1 (SCARB1), low-density lipoprotein receptor (LDLR), ATP binding cassette subfamily A member 1 (ABCA1) and ATP binding cassette subfamily G member 1 (ABCG1) was reduced in female and male placentas in the PEE group. Meanwhile, the proliferation decreased and the apoptosis increased in female and male placentas, and the insulin like growth factor 1 (IGF1) signal pathway was inhibited. in vitro, after being treated with ethanol (15, 30, 60, 120 mM) for 72 h, the expression of cholesterol transport genes was decreased, the apoptosis was increased, the proliferation was decreased and the IGF1 signal pathway was inhibited in BeWo cells, whereas exogenous IGF1 reversed these changes. In conclusion, by inhibiting the IGF1 signal pathway in placentas, PEE induced apoptosis and inhibited proliferation, thus decreased the cholesterol transport in placentas, and eventually leading to low blood cholesterol levels in foetal rats.

Synergistic effects of prenatal nicotine exposure and post-weaning high-fat diet on hypercholesterolaemia in rat offspring of different sexes

Hypercholesterolaemia is considered a disease with intrauterine origin. Recently, we reported that prenatal nicotine exposure (PNE) induced an abnormal level of total cholesterol in rat offspring before and after birth. However, there were little data about sex differences in serum cholesterol level in PNE offspring. In addition, many previous studies reported that blood cholesterol is associated with daily diet. This study was designed to analyse the interaction among PNE, high-fat diet (HFD) and sex on cholesterol metabolism in the rat. Pregnant Wistar rats were administered 2 mg/kg nicotine subcutaneously from gestational day (GD) 11 until parturition. After weaning, pups were fed with normal diet or HFD till 24 weeks, and then, serum cholesterol phenotypes and hepatic cholesterol metabolism-related genes were tested. Results showed that PNE manifested a distinct programming effect on cholesterol phenotype and cholesterol metabolism-related genes. HFD aggregated PNE-induced hypercholesterolaemia in adult offspring and exacerbated liver cholesterol metabolism dysfunction in PNE offspring. There was no sex difference in serum cholesterol level, but there were interactions among PNE, HFD and sex on cholesterol metabolic genes in adult offspring, which indicates that cholesterol metabolism in female offspring is more likely to be affected by PNE and HFD. In conclusion, HFD exacerbated PNE-induced hypercholesterolaemia, and sex differences existed in liver cholesterol metabolic genes in PNE- or HFD-treated offspring.

Influencing factors, underlying mechanism and interactions affecting hypercholesterolemia in adult offspring with caffeine exposure during pregnancy

Epidemiological surveys suggest that adult hypercholesterolemia has an intrauterine origin and exhibits gender differences. Our previous study demonstrated that adult rats with intrauterine growth retardation (IUGR) offspring rats induced by prenatal caffeine exposure (PCE) had a higher serum total cholesterol (TCH) level. In this study, we aimed to analyze the influencing factors, underlying mechanism and interactions affecting hypercholesterolemia in adult offspring with caffeine exposure during pregnancy. Pregnant rats were administered caffeine (120 mg/kg d) from gestational day 11 until delivery. Offspring rats fed a normal diet or a high-fat diet (HFD) were euthanized at postnatal week 24, and blood and liver samples were collected. The results showed that PCE could increase the serum levels of TCH and low-density lipoprotein-cholesterol (LDL-C), and the hepatic expression of HMG CoA reductase (HMGCR) and apolipoprotein B (ApoB), but decreased the high-density lipoprotein-cholesterol (HDL-C) level and the hepatic expression of scavenger receptor B1 (SR-B1) and LDL receptor (LDLR). Furthermore, PCE, HFD and gender interact with each other to influence the serum cholesterol phenotype and expression of hepatic cholesterol metabolic genes. These results suggest that the hypercholesterolemia in adult offspring rats induced by PCE mainly resulted from enhanced synthesis and the weakened reverse transport of cholesterol in the liver, furthermore HFD could aggravate this effect, which is caused by hepatic cholesterol metabolic disorders. Moreover, cholesterol metabolism in female rats was more sensitive to neuroendocrine changes and HFD than that in males. This study confirmed the influencing factors (such as a HFD and female gender) of hypercholesterolemia in IUGR offspring providing theoretical and experimental bases for the effective prevention of fetal-originated hypercholesterolemia.

Fetal over- and undernutrition differentially program thyroid axis adaptability in adult sheep

OBJECTIVE

We aimed to test, whether fetal under- or overnutrition differentially program the thyroid axis with lasting effects on energy metabolism, and if early-life postnatal overnutrition modulates implications of prenatal programming.

DESIGN

Twin-pregnant sheep (n = 36) were either adequately (NORM), under- (LOW; 50% of NORM) or overnourished (HIGH; 150% of energy and 110% of protein requirements) in the last-trimester of gestation. From 3 days-of-age to 6 months-of-age, twin lambs received a conventional (CONV) or an obesogenic, high-carbohydrate high-fat (HCHF) diet. Subgroups were slaughtered at 6-months-of-age. Remaining lambs were fed a low-fat diet until 2½ years-of-age (adulthood).

METHODS

Serum hormone levels were determined at 6 months- and 2½ years-of-age. At 2½ years-of-age, feed intake capacity (intake over 4-h following 72-h fasting) was determined, and an intravenous thyroxine tolerance test (iTTT) was performed, including measurements of heart rate, rectal temperature and energy expenditure (EE).

RESULTS

In the iTTT, the LOW and nutritionally mismatched NORM:HCHF and HIGH:CONV sheep increased serum T₃, T₃:T₄ and T₃:TSH less than NORM:CONV, whereas TSH was decreased less in HIGH, NORM:HCHF and LOW:HCHF. Early postnatal exposure to the HCHF diet decreased basal adult EE in NORM and HIGH, but not LOW, and increased adult feed intake capacity in NORM and LOW, but not HIGH.Conclusions: The iTTT revealed a differential programming of central and peripheral HPT axis function in response to late fetal malnutrition and an early postnatal obesogenic diet, with long-term implications for adult HPT axis adaptability and associated consequences for adiposity risk.

Prenatal food restriction induces neurobehavioral abnormalities in adult female offspring rats and alters intrauterine programming

The higher risk of adult neuropsychiatric diseases in individuals with low fetal birth weight may be related to brain-derived neurotrophic factor (BDNF) signaling pathway inhibition. Here, we investigated whether prenatal food restriction (PFR) induces neurobehavioral alterations in adult female offspring and explored the underlying intrauterine programming mechanism. Pregnant Wistar rats in the PFR group were fed 50% of the daily food intake of control rats from gestational day (GD) 11 to 20; some pregnant rats were sacrificed at GD20, and the remaining female pups had normal delivery and were fed a post-weaning high-fat diet (HFD) and half of them were exposed to an unpredictable chronic stress (UCS) from postnatal week (PW) 21. All adult female offspring were sacrificed at PW24. At GD20, PFR altered fetal hippocampal structure and function, increased glucocorticoid receptor (GR) expression, and decreased mineralocorticoid receptor (MR), BDNF and synaptic plasticity-related gene expressions. At PW24, PFR induced depression-like behavioral abnormalities in adult rat offspring fed an HFD. These rats exhibited depression- and anxiety-like behavioral changes after HFD/UCS. Furthermore, the hippocampal morphology of the PFR group showed abnormal changes in adult offspring fed an HFD and more serious damage after HFD/UCS. These changes were accompanied by increased serum corticosterone levels, elevated GR expression, and reduced expression of the BDNF signaling pathway and synaptic plasticity-related genes in the hippocampus. In conclusion, PFR may induce neurobehavioral abnormalities in adult offspring, especially those exposed to UCS, through high levels of glucocorticoids, which increase hippocampal GR expression and decrease BDNF expression.

Steroidogenic factor-1 hypermethylation in maternal rat blood could serve as a biomarker for intrauterine growth retardation

Intrauterine growth retardation (IUGR) is a common obstetric complication lacking an optimal method for prenatal screening. DNA methylation profile in maternal blood holds significant promise for prenatal screening. Here, we aimed to screen out potential IUGR biomarkers in maternal blood from the perspective of DNA methylation. The IUGR rat model was established by prenatal maternal undernutrition. High-throughput bisulfite sequencing of genomic DNA methylation followed by functional clustering analysis for differentially methylated region (DMR)-associated genes demonstrated that genes regulating transcription had the most significantly changed DNA methylation status in maternal blood with IUGR. Genes about apoptosis and placental development were also changed. Besides increased placental apoptosis, IUGR rats demonstrated the same hypermethylated CpG sites of steroidogenic factor-1 (SF-1, a DMR-associated transcription factor about placenta) promoter in maternal blood and placentae. Further, ff1b, the SF-1 ortholog, was knocked out in zebrafish by CRISPR/Cas9 technology. The knock-out zebrafish demonstrated developmental inhibition and increased IUGR rates, which confirmed the role of SF-1 in IUGR development. Finally, hypermethylated SF-1 was observed in human maternal blood of IUGR. This study firstly presented distinct DNA methylation profile in maternal blood of IUGR and showed hypermethylated SF-1 could be a potential IUGR biomarker in maternal rat blood.

High-fat diet and chronic stress aggravate adrenal function abnormality induced by prenatal caffeine exposure in male offspring rats

We previously demonstrated thatprenatal caffeine exposure (PCE) suppressed fetal adrenal steroidogenesis and resulted in developmental programming changes in offspring rats. However, whether these changes play a role in adrenal corticosterone synthesis under high-fat diet (HFD) and unpredictable chronic stress (UCS) remains unknown. In present study, rat model was established by PCE (120 mg/kg.d), and male offspring were provided normal diet or HFD after weaning. At postnatal week 21, several rats fed HFD were exposed to UCS for 3 weeks and sacrificed. The results showed that compared with the corresponding control group, the serum corticosterone levels and adrenal steroid synthetase expression of the PCE offspring without UCS were reduced. Moreover, the glucocorticoid (GC)-activation system was inhibited, and insulin-like growth factor 1 (IGF1) signaling pathway expression was increased. With UCS exposure in the PCE offspring, serum corticosterone levels and adrenal steroid synthetase expression were increased, the activity of GC-activation system was enhanced, and adrenal IGF1 signaling pathway expression was decreased. Based on these findings, PCE induced adrenal hypersensitivity in adult male offspring rats, as shown by the reduced corticosterone levels under HFD conditions but significantly enhanced corticosterone levels with UCS, in which GC-IGF1 axis programming alteration may play an important role.

Intrauterine growth retardation-associated syncytin b hypermethylation in maternal rat blood revealed by DNA methylation array analysis

BackgroundEmerging evidence suggests that DNA methylation in maternal blood is a promising target for intrauterine growth retardation (IUGR) screening, a common developmental toxicity. Here, we aimed to screen out IUGR-related DNA methylation status in maternal blood via high-throughput profiling.MethodsPregnant Wistar rats were subcutaneously administered nicotine (1 mg/kg) twice per day from gestational day (GD) 11 to GD20 to establish the IUGR model. MeDIP array assays and the following GO analysis were used to evaluate DNA methylation status in maternal blood. One placental development-associated gene was selected for further confirmation.ResultsGenes regulating the development of multiple organs and major body systems had changed DNA methylation frequencies in the maternal blood of IUGR rats. Placental development, which can affect the development of multiple fetal organs and induce IUGR, is a hypermethylated cluster consisting of four significantly changed genes, including syncytin b (Synb), Lrrc15, Met, and Tex19.1. With the most significant change, Synb hypermethylation in maternal blood was confirmed by bisulfite-sequencing PCR (BSP). Moreover, decreased Synb expression and histological changes were observed in IUGR placentae.ConclusionThe IUGR-associated DNA methylation profile in maternal blood, such as placenta-related Synb hypermethylation, provides evidence for further studies on possible IUGR biomarkers.

Prenatal Food Restriction with Postweaning High-fat Diet Alters Glucose Metabolic Function in Adult Rat Offspring

BACKGROUND AND AIMS

The present study was designed to investigate the effects of prenatal food restriction (PFR) with postweaning high-fat diet (HFD) on glucose metabolic function in adult offspring.

METHODS

Pregnant Wistar rats were given PFR treatment from gestational day 11 to spontaneous delivery. All pups were fed by HFD after weaning. Oral glucose tolerance test (OGTT) was conducted at postnatal week (PW) 20. Rats were decapitated in PW24 to collect liver and pancreas, and expression of hepatic insulin signaling genes were then quantified.

RESULTS

Body weight from PW4 to PW24 in PFR males was lower than those in control males, whereas there was no distinct difference between females. However, body weight gain rates were higher from PW16 to PW24 in PFR males and females. Fasting serum glucose presented no changes, whereas fasting serum insulin decreased in PW20 in PFR pups. Moreover, glucose intolerance only appeared in PFR males, whereas no changes were shown in PFR females in relative values. Serum insulin increased in both PFR groups after OGTT. Remarkable pathological changes were also found in islets from PFR rats. There was an increase in the hepatic mRNA expression of IR in PFR females and of Glut2 in PFR males.

CONCLUSION

PFR with postweaning HFD induced a catch-up growth in body weight, especially in PFR females. Serum insulin decreased in both PFR groups in fasting status. Insulin resistance after OGTT only existed in PFR males, whereas PFR females showed no obvious changes in glucose metabolism.

Hypothalamic-pituitary-adrenal axis hypersensitivity in female rats on a post-weaning high-fat diet after chronic mild stress

A high-fat diet (HFD) is highly correlated to obesity, metabolic diseases and certain behavioral changes. However, the effects of post-weaning HFD in rats during puberty and the role of the hypothalamic-pituitary-adrenal (HPA) axis in this process have remained elusive. The present study hypothesized that the HPA axis mediates the behavioral alterations induced by a post-weaning HFD. To investigate this, female rats were divided into two groups, one of which was fed a HFD from postnatal weeks (PWs) 4-12, while the other group received standard chow. Rats in each group were then subdivided into two subgroups each, and from PW 9-12, animals from one of the two subgroups were subjected to chronic mild stress (CMS), while the other subgroup received no stress. At PW 12, the body weight of rats receiving a HFD but no DMS was significantly higher than that in the control group. The frequency of crossing and rearing in the open field test and the time in the center of the Y-maze were decreased following CMS. Total time to escape was decreased in rats receiving HFD and after CMS. The serum levels of adrenocorticotropic hormone and corticosterone were increased in rats receiving an HFD and after CMS, and the mRNA levels of corticotropin-releasing hormone and arginine vasopressin in the hypothalamus were increased in the HFD + CMS group compared to that in the control group. The mRNA expression of glucocorticoid receptor (GR) in the hippocampi of rats in the HFD + CMS group was significantly decreased and the mineralocorticoid receptor/GR ratio was increased compared to that in the groups receiving either CMS or a HFD. In conclusion, these results indicated that female rats fed a post-weaning HFD showed HPA axis hypersensitivity under CMS, which may mediate behavioral alterations.

Sonographic Evaluation of Fetal Adrenal Gland in Gestational Diabetes: Relation to Fetal Growth and Maternal Biochemical Markers

OBJECTIVES

To relate measurements and volume of the fetal adrenal gland in third trimester ultrasound in diabetic pregnancies (1) to birth weight; (2) to other sonographic markers of diabetic fetopathy (expected fetal weight, sectional area, and fractional volume in fetal limbs); and (3) to maternal biochemical markers of diabetes (HbA1c, leptin).

METHODS

Fetal adrenal gland measurements were obtained between 32 and 34 weeks. The gland length, width, depth, and volume (by Virtual Organ Computer-Aided Analysis [VOCAL]) were measured for total gland and fetal zone. Fetal total and fat sectional area and fractional volume were obtained in arm and thigh. A maternal blood sample was obtained. Univariate and multivariate models were used to assess the associations.

RESULTS

Thirty-nine diabetic pregnancies were included. Birth weight related significantly to total and fetal zone adrenal depth, and total adrenal volume in third trimester. Total adrenal length and corrected adrenal gland volume also showed a significant correlation to birth weight percentile in univariate and multivariate models. Total adrenal volume associated significantly to total and fat areas and volumes in fetal limbs. Both maternal leptin and HbA1c levels found a significant positive relation to fetal total adrenal volume and corrected adrenal gland volume. Total adrenal gland volume showed a significant association to maternal HbA1c level in multivariate model.

CONCLUSIONS

An enlargement of the fetal adrenal gland may be observed in gestational diabetes, not only related to birth weight, but also to distinctive features of diabetic pregnancies, such as fat tissue fetal deposits or maternal biochemical markers.

Intrauterine Growth Restriction: Hungry for an Answer

Intrauterine growth restriction (IUGR) has been defined in several ways, but in general describes a condition in which the fetus exhibits poor growth in utero. This complication of pregnancy poses a significant public health burden as well as increased morbidity and mortality for the offspring. In human IUGR, alteration in fetal glucose and insulin homeostasis occurs in an effort to conserve energy and survive at the expense of fetal growth in an environment of inadequate nutrient provision. Several animal models of IUGR have been utilized to study the effects of IUGR on fetal glucose handling, as well as the postnatal reprogramming of energy metabolite handling, which may be unmasked in adulthood as a maladaptive propensity for cardiometabolic disease. This developmental programming may be mediated in part by epigenetic modification of essential regulators of glucose homeostasis. Several pharmacological therapies and nonpharmacological lifestyle modifications have shown early promise in mitigating the risk for or severity of adult metabolic phenotypes but still require further study of unanticipated and/or untoward side effects.

Prenatal food restriction induces poor-quality articular cartilage in female rat offspring fed a post-weaning high-fat diet and its intra-uterine programming mechanisms

Epidemiological data show that osteoarthritis (OA) is significantly associated with lower birth weight, and that OA may be a type of fetal-originated adult disease. The present study aimed to investigate the prenatal food-restriction (PFR) effect on the quality of articular cartilage in female offspring to explore the underlying mechanisms of fetal-originated OA. Maternal rats were fed a restricted diet from gestational day (GD) 11 to 20 to induce intra-uterine growth retardation. Female fetuses and female adult offspring fed a post-weaning high-fat diet were killed at GD20 and postnatal week 24, respectively. Serum and knee cartilage samples from fetuses and adult female offspring were collected and examined for cholesterol metabolism and histology. Fetal serum corticosterone and insulin-like growth factor-1 (IGF-1) in the PFR group were lower than those of the control, but the serum cholesterol level was not changed. The lower expression of IGF-1 in the PFR group lasted into adulthood. The expression of extracellular matrix (ECM) genes, including type II collagen, aggrecan and cholesterol efflux genes including liver X receptor, were significantly induced, but the ATP-binding-cassette transporter A1 was unchanged. PFR could induce a reduction in ECM synthesis and impaired cholesterol efflux in female offspring, and eventually led to poor quality of articular cartilage and OA.

Protein Restriction During the Last Third of Pregnancy Malprograms the Neuroendocrine Axes to Induce Metabolic Syndrome in Adult Male Rat Offspring

Metabolic malprogramming has been associated with low birth weight; however, the interplay between insulin secretion disruption and adrenal function upon lipid metabolism is unclear in adult offspring from protein-malnourished mothers during the last third of gestation. Thus, we aimed to study the effects of a maternal low-protein diet during the last third of pregnancy on adult offspring metabolism, including pancreatic islet function and morphophysiological aspects of the liver, adrenal gland, white adipose tissue, and pancreas. Virgin female Wistar rats (age 70 d) were mated and fed a protein-restricted diet (4%, intrauterine protein restricted [IUPR]) from day 14 of pregnancy until delivery, whereas control dams were fed a 20.5% protein diet. At age 91 d, their body composition, glucose-insulin homeostasis, ACTH, corticosterone, leptin, adiponectin, lipid profile, pancreatic islet function and liver, adrenal gland, and pancreas morphology were assessed. The birth weights of the IUPR rats were 20% lower than the control rats (P < .001). Adult IUPR rats were heavier, hyperphagic, hyperglycemic, hyperinsulinemic, hyperleptinemic, and hypercorticosteronemic (P < .05) with higher low-density lipoprotein cholesterol and lower high-density lipoprotein cholesterol, adiponectin, ACTH, and insulin sensitivity index levels (P < .01). The insulinotropic action of glucose and acetylcholine as well as muscarinic and adrenergic receptor function were impaired in the IUPR rats (P < .05). Maternal undernutrition during the last third of gestation disrupts the pancreatic islet insulinotropic response and induces obesity-associated complications. Such alterations lead to a high risk of metabolic syndrome, characterized by insulin resistance, visceral obesity, and lower high-density lipoprotein cholesterol.

Prenatal nicotine exposure induces poor articular cartilage quality in female adult offspring fed a high-fat diet and the intrauterine programming mechanisms

Prenatal nicotine exposure (PNE) induces skeletal growth retardation and dyslipidemia in offspring displaying intrauterine growth retardation (IUGR). Cholesterol accumulation resulting from cholesterol efflux dysfunction may reduce the quality of articular cartilage through fetal programming. This study evaluated the quality of articular cartilage of female adult offspring fed a high-fat diet and explored the mechanisms using a rat IUGR model established by the administration of 2.0mg/kg/d of subcutaneous nicotine from gestational days 11-20. The results demonstrated an increased OARSI (Osteoarthritis Research Society International) score and total cholesterol content, decreased serum corticosterone, and increased IGF1 and dyslipidemia with catch-up growth in PNE adult offspring. Cartilage matrix, IGF1 and cholesterol efflux pathway expression were reduced in PNE fetuses and adult offspring. Therefore, PNE induced poor articular cartilage quality in female adult offspring fed a high-fat diet via a dual programming mechanism.

Prenatal caffeine exposure induces a poor quality of articular cartilage in male adult offspring rats via cholesterol accumulation in cartilage

Epidemiological investigations indicate that osteoarthritis is associated with intrauterine growth retardation (IUGR) and abnormal cholesterol metabolism. Our previous studies showed that prenatal caffeine exposure (PCE) induced chondrogenesis retardation in IUGR offspring rats. The current study sought to investigate the effects of PCE on male IUGR offspring rats’ articular cartilage, and the mechanisms associated with abnormal cholesterol metabolism. Based on the results from both male fetal and adult fed a high-fat diet (HFD) studies of rats that experienced PCE (120 mg/kg.d), the results showed a poor quality of articular cartilage and cholesterol accumulation in the adult PCE group. Meanwhile, the serum total cholesterol and low-density lipoprotein-cholesterol concentrations were increased in adult PCE offspring. We also observed lower expression of insulin-like growth factor1 (IGF1) and impaired cholesterol efflux in adult articular cartilage. Furthermore, the expression of cartilage functional genes, components of the IGF1 signaling pathway and cholesterol efflux pathway related genes were decreased in PCE fetal cartilage. In conclusion, PCE induced a poor quality of articular cartilage in male adult offspring fed a HFD. This finding was shown to be due to cholesterol accumulation in the cartilage, which may have resulted from intrauterine reduced activity of the IGF1 signaling pathway.

Sex-specific increase in susceptibility to metabolic syndrome in adult offspring after prenatal ethanol exposure with post-weaning high-fat diet

Prenatal ethanol exposure (PEE) is an established risk factor for intrauterine growth retardation. The present study was designed to determine whether PEE can increase the susceptibility of high-fat diet (HFD)-induced metabolic syndrome (MS) in adult offspring in a sex-specific manner, based on a generalized linear model analysis. Pregnant Wistar rats were administered ethanol (4 g/kg.d) from gestational day 11 until term delivery. All offspring were fed either a normal diet or a HFD after weaning and were sacrificed at postnatal week 20, and blood samples were collected. Results showed that PEE reduced serum adrenocorticotropic hormone (ACTH) and corticosterone levels but enhanced serum glucose, insulin, insulin resistant index (IRI), triglyceride and total cholesterol (TC) concentrations. Moreover, the analysis showed interactions among PEE, HFD and sex. In the PEE offspring, HFD aggravated the decrease in ACTH and corticosterone levels and further increased serum glucose, insulin, triglyceride and TC levels. The changes of serum ACTH, glucose and IRI levels in the female HFD rats were greater than those in the male HFD rats. Our findings suggest that PEE enhances the susceptibility to MS induced by HFD in a sex-specific manner, which might be primarily associated with the neuroendocrine metabolic programming by PEE.

Prenatal nicotine exposure-induced intrauterine programming alteration increases the susceptibility of high-fat diet-induced non-alcoholic simple fatty liver in female adult offspring rats

“Two intrauterine programming”, involved in the intrauterine origin of high-fat diet-induced NAFL in female offspring rats, induced by prenatal nicotine exposure.

Prenatal ethanol exposure induces an intrauterine programming of enhanced sensitivity of the hypothalamic–pituitary–adrenal axis in female offspring rats fed with post-weaning high-fat diet

“Intrauterine programming” involved in the intrauterine origin of prenatal ethanol exposure induced enhanced sensitivity of the HPA axis in female offspring rats fed with high-fat diet.

Prenatal ethanol exposure programs an increased susceptibility of non-alcoholic fatty liver disease in female adult offspring rats

Prenatal ethanol exposure (PEE) induces dyslipidemia and hyperglycemia in fetus and adult offspring. However, whether PEE increases the susceptibility to non-alcoholic fatty liver disease (NAFLD) in offspring and its underlying mechanism remain unknown. This study aimed to demonstrate an increased susceptibility to high-fat diet (HFD)-induced NAFLD and its intrauterine programming mechanisms in female rat offspring with PEE. Rat model of intrauterine growth retardation (IUGR) was established by PEE, the female fetus and adult offspring that fed normal diet (ND) or HFD were sacrificed. The results showed that, in PEE+ND group, serum corticosterone (CORT) slightly decreased and insulin-like growth factor-1 (IGF-1) and glucose increased with partial catch-up growth; In PEE+HFD group, serum CORT decreased, while serum IGF-1, glucose and triglyceride (TG) increased, with notable catch-up growth, higher metabolic status and NAFLD formation. Enhanced liver expression of the IGF-1 pathway, gluconeogenesis, and lipid synthesis as well as reduced expression of lipid output were accompanied in PEE+HFD group. In PEE fetus, serum CORT increased while IGF-1 decreased, with low body weight, hyperglycemia, and hepatocyte ultrastructural changes. Hepatic IGF-1 expression as well as lipid output was down-regulated, while lipid synthesis significantly increased. Based on these findings, we propose a "two-programming" hypothesis for an increased susceptibility to HFD-induced NAFLD in female offspring of PEE. That is, the intrauterine programming of liver glucose and lipid metabolic function is "the first programming", and postnatal adaptive catch-up growth triggered by intrauterine programming of GC-IGF1 axis acts as "the second programming".

Intrauterine metabolic programming alteration increased susceptibility to non-alcoholic adult fatty liver disease in prenatal caffeine-exposed rat offspring

An increase in susceptibility to metabolic syndromes (MetS) in rat offspring that experienced prenatal caffeine exposure (PCE) has been previously demonstrated. The present study aimed to clarify this increased susceptibility and elucidate the mechanism of foetal origin that causes or contributes to adult non-alcoholic fatty liver disease (NAFLD) as a result of PCE. Based on the results from both foetal and adult studies of rats that experienced PCE (120 mg/kgd), the foetal weight and serum triglyceride levels decreased significantly and hepatocellular ultrastructure was altered. Foetal livers exhibited inhibited insulin-like growth factor-1 (IGF-1), enhanced lipogenesis and reduced lipid output. In adult female offspring of PCE+lab chow, lipid synthesis, oxidation and output were enhanced, whereas lipogenesis was inhibited in their male conterparters. Furthermore, in adult offspring of PCE+ high-fat diet, catch-up growth appeared obvious with enhanced hepatic IGF-1, especially in females. Both males and females showed increased lipid synthesis and reduced output, which were accompanied by elevated serum triglyceride. Severe NAFLD appeared with higher Kleiner scores. Gluconeogenesis was continuously enhanced in females. Therefore, increased susceptibility to diet-induced NAFLD in PCE offspring was confirmed, and it appears to be mediated by intrauterine glucose and alterations in lipid metabolic programming. This altered programming enhanced foetal hepatic lipogenesis and reduced lipid output in utero, which continued into the postnatal phase and reappeared in adulthood with the introduction of a high-fat diet, thereby aggravating hepatic lipid accumulation and causing NAFLD.