Conditional knockout of leptin receptor in the female reproductive tract reduces fertility due to parturition defects in mice.

Leptin is required for fertility, including initiation of estrous cycles. It is therefore challenging to assess the role of leptin signaling during pregnancy. Although neuron-specific transgene approaches suggest that leptin signaling in the central nervous system is most important, experiments with pharmacologic inhibition of leptin in the uterus or global replacement of leptin during pregnancy suggest leptin signaling in the reproductive tract may be required. Here, conditional leptin receptor knockout (Lepr cKO) with a progesterone receptor-driven Cre recombinase was used to examine the importance of leptin signaling in pregnancy. Lepr cKO mice have almost no leptin receptor in uterus or cervix, and slightly reduced leptin receptor levels in corpus luteum. Estrous cycles and progesterone concentrations were not affected by Lepr cKO. Numbers of viable embryos did not differ between primiparous control and Lepr cKO dams on Days 6.5 and 17.5 of pregnancy, despite a slight reduction in the ratio of embryos to corpora lutea, showing that uterine leptin receptor signaling is not required for embryo implantation. Placentas of Lepr cKO dams had normal weight and structure. However, over four parities, Lepr cKO mice produced 22% fewer live pups than controls, and took more time from pairing to delivery by their fourth parity. Abnormal birth outcomes of either dystocia or dead pups occurred in 33% of Lepr cKO deliveries but zero control deliveries, and the average time to deliver each pup after crouching was significantly increased. Thus, leptin receptor signaling in the reproductive tract is required for normal labor and delivery.

Transcription Factor PLAGL1 Is Associated with Angiogenic Gene Expression in the Placenta.

During pregnancy, the placenta is important for transporting nutrients and waste between the maternal and fetal blood supply, secreting hormones, and serving as a protective barrier. To better understand placental development, we must understand how placental gene expression is regulated. We used RNA-seq data and ChIP-seq data for the enhancer associated mark, H3k27ac, to study gene regulation in the mouse placenta at embryonic day (e) 9.5, when the placenta is developing a complex network of blood vessels. We identified several upregulated transcription factors with enriched binding sites in e9.5-specific enhancers. The most enriched transcription factor, PLAGL1 had a predicted motif in 233 regions that were significantly associated with vasculature development and response to insulin stimulus genes. We then performed several experiments using mouse placenta and a human trophoblast cell line to understand the role of PLAGL1 in placental development. In the mouse placenta, Plagl1 is expressed in endothelial cells of the labyrinth layer and is differentially expressed in placentas from mice with gestational diabetes compared to placentas from control mice in a sex-specific manner. In human trophoblast cells, siRNA knockdown significantly decreased expression of genes associated with placental vasculature development terms. In a tube assay, decreased PLAGL1 expression led to reduced cord formation. These results suggest that Plagl1 regulates overlapping gene networks in placental trophoblast and endothelial cells, and may play a critical role in placental development in normal and complicated pregnancies.

Effects of acute exposure to a high-fat, high-sucrose diet on gestational glucose tolerance and subsequent maternal health in mice.

Gestational diabetes mellitus (GDM) is a common obstetric complication. Half of women who have GDM will go on to develop type 2 diabetes. Understanding the mechanisms by which this occurs requires an animal model of GDM without ongoing diabetes at conception. C57Bl/6J mice react acutely to a high-fat, high-sucrose (HFHS) challenge. Here, we hypothesized that a periconceptional HFHS challenge will induce glucose intolerance during gestation. C57Bl/6J female mice were placed on an HFHS either 1 or 3 weeks prior to mating and throughout pregnancy. Intraperitoneal glucose tolerance tests, insulin measurements, and histological analysis of pancreatic islets were used to assess the impact of acute HFHS. C57Bl/6J females fed HFHS beginning 1 week prior to pregnancy became severely glucose intolerant, with reduced insulin response to glucose, and decreased pancreatic islet expansion during pregnancy compared to control mice. These GDM characteristics did not occur when the HFHS diet was started 3 weeks prior to mating, suggesting the importance of acute metabolic stress. Additionally, HFHS feeding resulted in only mild insulin resistance in nonpregnant females. When the diet was discontinued at parturition, symptoms resolved within 3 weeks. However, mice that experienced glucose intolerance in pregnancy became glucose intolerant more readily in response to a HFHS challenge later in life than congenic females that experienced a normal pregnancy, or that were fed the same diet outside of pregnancy. Thus, acute HFHS challenge in C57Bl/6 mice results in a novel, nonobese, animal model that recapitulates the long-term risk of developing type 2 diabetes following GDM.

Maternal exposure to bisphenol A and genistein has minimal effect on A(vy)/a offspring coat color but favors birth of agouti over nonagouti mice.

Reports that maternal diet influences coat color in mouse offspring carrying the agouti A(vy) allele have received considerable attention because the range, from pseudoagouti (brown) to yellow, predicts adult health outcomes, especially disposition toward obesity and diabetes, in yellower mice. Bisphenol A (BPA), an endocrine-disrupting compound with estrogenic properties, fed to a/a dams harboring A(vy)/a conceptuses has been reported to induce a significant shift toward yellower mice, whereas consumption of either genistein (G) alone or in combination with BPA led to greater numbers of healthy, brown offspring. Groups of C57/B6 a/a females, which are nonagouti, were fed either a phytoestrogen-free control diet or one of six experimental diets: diets 1-3 contained BPA (50 mg, 5 mg, and 50 µg BPA/kg food, respectively); diet 4 contained G (250 mg/kg food); diet 5 contained G plus BPA (250 and 50 mg/kg food, respectively); and diet 6 contained 0.1 µg of ethinyl estradiol (EE)/kg food. Mice were bred to A(vy)/a males over multiple parities. In all, 2,824 pups from 426 litters were born. None of the diets provided any significant differences in relative numbers of brown, yellow, or intermediate coat color A(vy)/a offspring. However, BPA plus G (P < 0.0001) and EE diets (P = 0.005), but not the four others, decreased the percentage of black (a/a) to A(vy)/a offspring from the expected Mendelian ratio of 1:1. Data suggest that A(vy)/a conceptuses, which may possess a so-called "thrifty genotype," are at a competitive advantage over a/a conceptuses in certain uterine environments.

Placental changes caused by food restriction during early pregnancy in mice are reversible.

In a previous study, 50% calorie restriction in mice from d1.5 to 11.5 of pregnancy resulted in reduced placental weights and areas,relative sparing of labyrinth zone area compared to junctional zone area, and dramatic changes in global gene expression profiles.However, little lasting effect was seen on adult offspring of these pregnancies, with a slight reduction in adiposity in males and some changes in liver gene expression in both sexes. The goals of the present study were to determine whether the placental changes induced by caloric restriction in early pregnancy had permanent, irreversible effects on the placenta, and whether the changes in liver gene expression in adult offspring were present before birth. There were no differences in placental weights or areas, or the areas of individual placental zones near term in mice that had previously been food restricted. Global gene expression profiles at d18.5 were indistinguishable in placentas from control and previously food-restricted mothers. In fetuses from restricted dams at d18.5, liver expression of Gck, a key regulator of glycogen synthesis, was reduced, whereas its expression was increased in livers from adult offspring of restricted dams. Ppara expression was also reduced in fetal livers from restricted dams at d18.5, but not in adult offspring livers. We conclude that alterations in the placenta caused by nutrient restriction in early pregnancy are reversible, and that alterations in gene expression in livers of adult offspring are not a result of changes initiated during pregnancy and maintained through adulthood.

The uterine secretome initiates growth of gynecologic tissues in ectopic locations.

Endosalpingiosis (ES) and endometriosis (EM) refer to the growth of tubal and endometrial epithelium respectively, outside of their site of origin. We hypothesize that uterine secretome factors drive ectopic growth. To test this, we developed a mouse model of ES and EM using tdTomato (tdT) transgenic fluorescent mice as donors. To block implantation factors, progesterone knockout (PKO) tdT mice were created. Fluorescent lesions were present after oviduct implantation with and without WT endometrium. Implantation was increased (p<0.05) when tdt oviductal tissue was implanted with endometrium compared to oviductal tissue alone. Implantation was reduced (p<0.0005) in animals implanted with minced tdT oviductal tissue with PKO tdT endometrium compared to WT endometrium. Finally, oviductal tissues was incubated with and without a known implantation factor, leukemia inhibitory factor (LIF) prior to and during implantation. LIF promoted lesion implantation. In conclusion, endometrial derived implantation factors, such as LIF, are necessary to initiate ectopic tissue growth. We have developed an animal model of ectopic growth of gynecologic tissues in a WT mouse which will potentially allow for development of new prevention and treatment modalities.

Gestational diabetes augments group B Streptococcus infection by disrupting maternal immunity and the vaginal microbiota.

Group B Streptococcus (GBS) is a pervasive perinatal pathogen, yet factors driving GBS dissemination in utero are poorly defined. Gestational diabetes mellitus (GDM), a complication marked by dysregulated immunity and maternal microbial dysbiosis, increases risk for GBS perinatal disease. Using a murine GDM model of GBS colonization and perinatal transmission, we find that GDM mice display greater GBS in utero dissemination and subsequently worse neonatal outcomes. Dual-RNA sequencing reveals differential GBS adaptation to the GDM reproductive tract, including a putative glycosyltransferase (yfhO), and altered host responses. GDM immune disruptions include reduced uterine natural killer cell activation, impaired recruitment to placentae, and altered maternofetal cytokines. Lastly, we observe distinct vaginal microbial taxa associated with GDM status and GBS invasive disease status. Here, we show a model of GBS dissemination in GDM hosts that recapitulates several clinical aspects and identifies multiple host and bacterial drivers of GBS perinatal disease.

Role of adrenomedullin2/ intermedin in pregnancy induced vascular and metabolic adaptation in mice.

Introduction: Adrenomedullin2 (AM2) shares its receptor with Calcitonin gene related peptide and adrenomedullin with overlapping but distinct biological functions. Goal of this study was to assess the specific role of Adrenomedullin2 (AM2) in pregnancy induced vascular and metabolic adaptation using AM2 knockout mice (AM2 -/-). Method : The AM2 -/- mice were successfully generated using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Nuclease Cas nine system. Phenotype of pregnant AM2 -/- mice was assessed with respect to its fertility, blood pressure regulation, vascular health and metabolic adaptations and compared to the wild type littermates (AM2 +/+). Results : Current data shows that AM2 -/- females are fertile with no significant difference in number of pups/litter compared to the AM2 +/+. However, ablation of AM2 decreases the gestational length and the total number of pups born dead or that die after birth is greater in AM2 -/- mice compared to AM2 +/+ mice (p < 0.05). Further AM2 -/- mice exhibit elevated blood pressure and elevated vascular sensitivity for the contractile responses to angiotensin two and higher serum sFLT-1 trigylcerides levels compared to AM2 +/+(p < 0.05). In addition, AM2 -/- mice develop glucose intolerance with elevated serum levels of Insulin during pregnancy compared to the AM2 +/+mice. Discussion: Current data suggests a physiological role for AM2 in pregnancy induced vascular and metabolic adaptations in mice.

Leptin and the placental response to maternal food restriction during early pregnancy in mice.

Several studies have demonstrated that maternal undernutrition or overnutrition during pregnancy can have negative consequences for the health of children born to these pregnancies, but the physiological mechanisms by which this occurs are not completely understood. During periods of food restriction, concentrations of leptin decline, whereas leptin is elevated in obesity, suggesting that it may play a role in the response to altered nutrition during pregnancy. This study compares placental development and global placental gene expression profiles at Day 11.5 in pregnant control mice, mice that were undernourished, and mice that were undernourished but given leptin. Placentas from mothers exposed to food restriction preserved the placental labyrinth zone at the expense of the junctional zone, an effect abrogated in the restricted plus leptin group, which had a significant decrease in the labyrinth zone area compared with controls. Similarly, there were more significant differences in gene expression between placentas from control and restricted plus leptin mothers (1128 differentially expressed genes) than between placentas of control and restricted mothers (281 differentially expressed genes). We conclude that the presence of high concentrations of circulating leptin during food restriction disrupts the normal adaptive response of the placenta to reduced energy availability.

The expression and potential function of bone morphogenetic proteins 2 and 4 in bovine trophectoderm.

BACKGROUND: Bone morphogenetic proteins (BMPs) were first described for their roles in bone formation, but they now also are known to possess additional activities, including those relating to embryogenesis. The objectives of this work were to 1) determine if peri-attachment bovine conceptuses and bovine trophoblast cells (CT1) contain transcripts for BMP2 and 4, an innate inhibitor noggin (NOG), and BMP2/4 receptors (BMPRII, ACVR1, BMPR1A, BMPR1B), and 2) determine if BMP2 or 4 supplementation to CT1 cells affects cell proliferation, differentiation or trophoblast-specific gene expression. METHODS: RNA was isolated from day 17 bovine conceptuses and CT1 cells. After RT-PCR, amplified products were cloned and sequenced. In other studies CT1 cells were treated with BMP2 or 4 at various concentrations and effects on cell viability, cell differentiation and abundance of IFNT and CSH1 mRNA were evaluated. RESULTS: Transcripts for BMP2 and 4 were detected in bovine conceptuses and CT1 cells. Also, transcripts for each BMP receptor were detected in conceptuses and CT1 cells. Transcripts for NOG were detected in conceptuses but not CT1 cells. Cell proliferation was reduced by BMP4 but not BMP2 supplementation. Both factors reduced IFNT mRNA abundance but had no effect on CSH1 mRNA abundance in CT1 cells. CONCLUSIONS: The BMP2/4 ligand and receptor system presides within bovine trophectoderm prior to uterine attachment. BMP4 negatively impacts CT1 cell growth and both BMPs affect IFNT mRNA abundance.

A novel model of gestational diabetes: Acute high fat high sugar diet results in insulin resistance and beta cell dysfunction during pregnancy in mice.

Gestational diabetes mellitus (GDM) affects 7-18% of all pregnancies. Despite its high prevalence, there is no widely accepted animal model. To address this, we recently developed a mouse model of GDM. The goal of this work was to further characterize this animal model by assessing insulin resistance and beta cell function. Mice were randomly assigned to either control (CD) or high fat, high sugar (HFHS) diet and mated 1 week later. At day 0 (day of mating) mice were fasted and intraperitoneal insulin tolerance tests (ipITT) were performed. Mice were then euthanized and pancreata were collected for histological analysis. Euglycemic hyperinsulinemic clamp experiments were performed on day 13.5 of pregnancy to assess insulin resistance. Beta cell function was assessed by glucose stimulated insulin secretion (GSIS) assay performed on day 0, 13.5 and 17.5 of pregnancy. At day 0, insulin tolerance and beta cell numbers were not different. At day 13.5, glucose infusion and disposal rates were significantly decreased (p<0.05) in Pregnant (P) HFHS animals (p<0.05) suggesting development of insulin resistance in P HFHS dams. Placental and fetal glucose uptake was significantly increased (p<0.01) in P HFHS dams at day 13.5 of pregnancy and by day 17.5 of pregnancy fetal weights were increased (p<0.05) in P HFHS dams compared to P CD dams. Basal and secreted insulin levels were increased in HFHS fed females at day 0, however at day 13.5 and 17.5 GSIS was decreased (p<0.05) in P HFHS dams. In conclusion, this animal model results in insulin resistance and beta cell dysfunction by mid-pregnancy further validating its relevance in studying the pathophysiology GDM.

Adrenomedullin and its receptors are expressed in mouse pancreatic ß-cells and suppresses insulin synthesis and secretion.

Gestational diabetes mellitus (GDM) is associated with defective pancreatic ß-cell adaptation in pregnancy, but the underlying mechanism remains obscure. Our previous studies demonstrated that GDM women display increased plasma adrenomedullin (ADM) levels, and non-obese GDM mice show decreased serum concentrations of insulin and the number of ß-cells in pancreas islets. The aims of this study is to examine if ADM and its receptors are expressed in female mouse pancreas, and if so, whether insulin secretion is regulated by ADM in mouse ß-cell line, NIT-1 cells and isolated mouse pancreatic islets. Present study shows that ADM and its receptor components CRLR, RAMPs are present in mouse pancreatic islets and co-localized with insulin. The expressions of ADM, CRLR and RAMP2 in islets from pregnant mice are reduced compared to that of non-pregnant mice. NIT-1-ß cells express ADM and its receptor mRNA, and glucose dose-dependently stimulates expressions. Furthermore, ADM inhibits NIT-1-ß cell growth, and this inhibition is reversed by ADM antagonist, ADM22-52. The glucose-induced insulin secretion was suppressed by ADM in NIT-1-ß cells and isolated pancreatic islets from pregnant mice. These inhibitory effects are accompanied by upregulation of endoplasmic reticulum (ER) stress biomarker genes in NIT-1-ß cells. This study unveils that reduced ADM and its receptors may play a role in ß-cell adaptation during pregnancy, while increased plasma ADM in GDM may contribute to the ß-cells dysfunction, and blockade of ADM may reverse ß-cell insulin production.

Consequences of conceptus exposure to colony-stimulating factor 2 on survival, elongation, interferon-τ secretion, and gene expression.

Exposure of bovine conceptuses to colony-stimulating factor 2 (CSF2) from days 5 to 7 of development can increase the percentage of transferred conceptuses that develop to term. The purpose of this experiment was to understand the mechanism by which CSF2 increases embryonic and fetal survival. Conceptuses were produced in vitro in the presence or absence of 10  ng/ml CSF2 from days 5 to 7 after insemination, transferred into cows, and flushed from the uterus at day 15 of pregnancy. There was a tendency (P=0.07) for the proportion of cows with a recovered conceptus to be greater for those receiving a CSF2-treated conceptus (35% for control versus 66% for CSF2). Antiviral activity in uterine flushings, a measure of the amount of interferon-τ (IFNT2) secreted by the conceptus, tended to be greater for cows receiving CSF2-treated conceptuses than for cows receiving control conceptuses. This difference approached significance when only cows with detectable antiviral activity were considered (P=0.07). In addition, CSF2 increased mRNA for IFNT2 (P=0.08) and keratin 18 (P<0.05) in extraembryonic membranes. Among a subset of filamentous conceptuses that were analyzed by microarray hybridization, there was no effect of CSF2 on gene expression in the embryonic disc or extraembryonic membranes. Results suggest that the increase in calving rate caused by CSF2 treatment involves, in part, more extensive development of extraembryonic membranes and capacity of the conceptus to secrete IFNT2 at day 15 of pregnancy.

Brief high fat high sugar diet results in altered energy and fat metabolism during pregnancy in mice.

During pregnancy several maternal adaptations occur in order to support the growing fetus which are further exacerbated by gestational diabetes mellitus (GDM). Previously we developed a mouse model of GDM, however we did not evaluate alterations to energy and fat metabolism. We have also shown that alterations in lipid metabolism are mediated by adrenomedullin (ADM) in normal and GDM pregnancies. Our objectives were: (1) evaluate energy and fat homeostasis in our GDM mouse model and (2) determine if ADM may play a role in these changes. Female mice were placed on either control (P-CD) or high fat, high sucrose diet (P-HFHS) 1 week prior to and throughout pregnancy. Mice were placed into comprehensive lab animal monitoring system (CLAMS) chambers throughout pregnancy. Visceral adipose tissue (VAT) was collected at d17.5 of pregnancy for analysis. Energy Expenditure was significantly increased (p < 0.05) in P-HFHS dams compared to all other groups. VAT ex-vivo lipolysis was increased (p < 0.05) in P-HFHS compared to P-CD dams. VAT gene expression of ADM receptors Crlr, Ramp2, and Ramp3 was increased (p < 0.05) in P-HFHS dams. ADM dose dependently increased ex vivo lipolysis. This data further validates our animal model of GDM and is usefulness in investigating the pathophysiology of GDM.

Several fibroblast growth factors are expressed during pre-attachment bovine conceptus development and regulate interferon-tau expression from trophectoderm.

The trophectoderm-derived factor interferon tau (IFNT) maintains the uterus in a pregnancy-receptive state in cattle and sheep. Fibroblast growth factors (FGFs) are implicated in regulating IFNT expression and potentially other critical events associated with early conceptus development in cattle. The overall objectives of this work were to identify the various FGFs and FGF receptors (FGFRs) expressed in elongating pre-attachment bovine conceptuses and determine if these FGFs regulate conceptus development and/or mediate IFNT production. In vitro-derived bovine blastocysts and in vivo-derived elongated conceptuses collected at day 17 of pregnancy express at least four FGFR subtypes (R1c, R2b, R3c, R4). In addition, transcripts for FGF1, 2, and 10 but not FGF7 are present in elongated bovine conceptuses. The expression pattern of FGF10 most closely resembled that of IFNT, with both transcripts remaining low in day 8 and day 11 conceptuses and increasing substantially in day 14 and day 17 conceptuses. Supplementation with recombinant FGF1, 2 or 10 increased IFNT mRNA levels in bovine trophectoderm cells and bovine blastocysts and increased IFNT protein concentrations in trophectoderm-conditioned medium. Blastocyst development was not affected by any of the FGFs. In summary, at least four FGFRs reside in pre- and peri-attachment bovine conceptuses. Moreover, conceptuses express at least three candidate FGFs during elongation, the time of peak IFNT expression. These findings provide new insight for how conceptus-derived factors such as FGF1, 2, and 10 may control IFNT expression during early pregnancy in cattle.

Impact of adrenomedullin blockage on lipid metabolism in female mice exposed to high-fat diet.

PURPOSE: Adrenomedullin (ADM) levels are elevated in gestational and type 2 diabetic patients. ADM also stimulates lipolysis in vitro. Disturbed lipid metabolism has been implicated in the pathogenesis of diabetes. Here, we explore whether blockade of ADM is beneficial for metabolic homeostasis in a diabetic mouse model. METHODS: C57BL/6J female mice were placed on either a control or a high fat high sucrose (HFHS) diet for 8 weeks. At week 4, osmotic mini-pumps were implanted for constant infusion of either saline or ADM antagonist, ADM22-52. Glucose tolerance tests were performed prior to infusion and 4 weeks after infusion began. Animals were then sacrificed and visceral adipose tissue collected for further analysis. RESULTS: Mice fed HFHS displayed glucose intolerance, increased mRNA expressions in VAT for Adm and its receptor components, Crlr. HFHS fed mice also had increased basal and isoprenaline-induced glycerol release by VAT explants. ADM22-52 did not significantly affect glucose intolerance. ADM22-52 did suppress basal and isoprenaline-induced glycerol release by VAT explants. This alteration was associated with enhanced mRNA expression of insulin signaling factors Insr and Glut4, and adipogenic factor Pck1. CONCLUSIONS: HFHS diet induces glucose intolerance and enhances ADM and its receptor expressions in VAT in female mice. ADM22-52 treatment did not affect glucose intolerance in HFHS mice, but reduced both basal and isoprenaline-induced lipolysis, which is associated with enhanced expression of genes involved in adipogenesis. These results warrant further research on the effects of ADM blockade in improving lipid homeostasis in diabetic patients.

Changes in excitability and ion channel expression in neurons of the major pelvic ganglion in female type II diabetic mice.

Bladder cystopathy and autonomic dysfunction are common complications of diabetes, and have been associated with changes in ganglionic transmission and some measures of neuronal excitability in male mice. To determine whether type II diabetes also impacts excitability of ganglionic neurons in females, we investigated neuronal excitability and firing properties, as well as underlying ion channel expression, in major pelvic ganglion (MPG) neurons in control, 10-week, and 21-week Leprdb/db mice. Type II diabetes in Leprdb/db animals caused a non-linear change in excitability and firing properties of MPG neurons. At 10 weeks, cells exhibited increased excitability as demonstrated by an increased likelihood of firing multiple spikes upon depolarization, decreased rebound spike latency, and overall narrower action potential half-widths as a result of increased depolarization and repolarization slopes. Conversely, at 21 weeks MPG neurons of Leprdb/db mice reversed these changes, with spiking patterns and action-potential properties largely returning to control levels. These changes are associated with numerous time-specific changes in calcium, sodium, and potassium channel subunit mRNA levels. However, Principal Components Analysis of channel expression patterns revealed that rectification of excitability is not simply a return to control levels, but rather a distinct ion channel expression profile in 21-week Leprdb/db neurons. These data indicate that type II diabetes can impact the excitability of post-ganglionic, autonomic neurons of female mice, and suggest that the non-linear progression of these properties with diabetes may be the result of compensatory changes in channel expression that act to rectify disrupted firing patterns of Leprdb/db MPG neurons.

In Utero and Postnatal Exposure to High Fat, High Sucrose Diet Suppressed Testis Apoptosis and Reduced Sperm Count.

Obesity affects male fertility and maternal diabetes affects the offspring sperm epigenome. However, the effects of in utero exposure to maternal glucose intolerance in combination with postnatal high fat, high sucrose (HFHS) diet consumption on offspring spermatogenesis is not clear. The present study was designed to test these effects. One week before and during pregnancy, dams were fed either control or HFHS diet to induce gestational glucose intolerance, and returned to standard diet during lactation. Male offspring from each maternal group were split into control and HFHS-fed groups for eight weeks prior to sacrifice at 11, 19 or 31 weeks of age, and reproductive tissues were harvested for analysis of testicular germ cell apoptosis and sperm output. Postnatal HFHS diet suppressed spermatogonia apoptosis in all age groups and maternal HFHS diet reduced testosterone levels at 11 weeks. At 31 weeks of age, the postnatal HFHS diet increased body weight, and reduced epididymis weight and sperm count. The combination of in utero and postnatal exposure impacted sperm counts most significantly. In summary, HFHS diet during pregnancy puts male offspring at greater risk of infertility, particularly when combined with postnatal high fat diet feeding.

Maternal Hyperleptinemia Improves Offspring Insulin Sensitivity in Mice.

Maternal obesity and gestational diabetes are prevalent worldwide. Offspring of mothers with these conditions weigh more and are predisposed to metabolic syndrome. A hallmark of both conditions is maternal hyperleptinemia, but the role of elevated leptin levels during pregnancy on developmental programming is largely unknown. We previously found that offspring of hyperleptinemic mothers weighed less and had increased activity. The goal of this study was to determine whether maternal leptin affects offspring insulin sensitivity by investigating offspring glucose metabolism and lipid accumulation. Offspring from two maternal hyperleptinemic models were compared. The first model of hyperleptinemia is the Lepr(db/+) mouse, which has a mutation in one copy of the gene that encodes the leptin receptor, resulting in a truncated long form of the receptor, and hyperleptinemia. Wild-type females served as the control for the Lepr(db/+) females. For the second hyperleptinemic model, wild-type females were implanted with miniosmotic pumps, which released leptin (350 ng/h) or saline (as the control) just prior to mating and throughout gestation. In the offspring of these dams, we measured glucose tolerance; serum leptin, insulin, and triglyceride levels; liver triglycerides; pancreatic α- and ß-cell numbers; body composition; incidence of nonalcoholic fatty liver disease; and the expression of key metabolic genes in the liver and adipose tissue. We found that the offspring of hyperleptinemic dams exhibited improved glucose tolerance, reduced insulin and leptin concentrations, reduced liver triglycerides, and a lower incidence of nonalcoholic fatty liver disease. Overall, maternal hyperleptinemia was beneficial for offspring glucose and lipid metabolism.

Maternal Hyperleptinemia Is Associated with Male Offspring's Altered Vascular Function and Structure in Mice.

Children of mothers with gestational diabetes have greater risk of developing hypertension but little is known about the mechanisms by which this occurs. The objective of this study was to test the hypothesis that high maternal concentrations of leptin during pregnancy, which are present in mothers with gestational diabetes and/or obesity, alter blood pressure, vascular structure and vascular function in offspring. Wildtype (WT) offspring of hyperleptinemic, normoglycemic, Leprdb/+ dams were compared to genotype matched offspring of WT-control dams. Vascular function was assessed in male offspring at 6, and at 31 weeks of age after half the offspring had been fed a high fat, high sucrose diet (HFD) for 6 weeks. Blood pressure was increased by HFD but not affected by maternal hyperleptinemia. On a standard diet, offspring of hyperleptinemic dams had outwardly remodeled mesenteric arteries and an enhanced vasodilatory response to insulin. In offspring of WT but not Leprdb/+ dams, HFD induced vessel hypertrophy and enhanced vasodilatory responses to acetylcholine, while HFD reduced insulin responsiveness in offspring of hyperleptinemic dams. Offspring of hyperleptinemic dams had stiffer arteries regardless of diet. Therefore, while maternal hyperleptinemia was largely beneficial to offspring vascular health under a standard diet, it had detrimental effects in offspring fed HFD. These results suggest that circulating maternal leptin concentrations may interact with other factors in the pre- and post -natal environments to contribute to altered vascular function in offspring of diabetic pregnancies.