Estradiol cycling drives female obesogenic adipocyte hyperplasia.

White adipose tissue (WAT) distribution is sex dependent. Adipocyte hyperplasia contributes to WAT distribution in mice driven by cues in the tissue microenvironment, with females displaying hyperplasia in subcutaneous and visceral WAT, while males and ovariectomized females have visceral WAT (VWAT)-specific hyperplasia. However, the mechanism underlying sex-specific hyperplasia remains elusive. Here, transcriptome analysis in female mice shows that high-fat diet (HFD) induces estrogen signaling in adipocyte precursor cells (APCs). Analysis of APCs throughout the estrous cycle demonstrates increased proliferation only when proestrus (high estrogen) coincides with the onset of HFD feeding. We further show that estrogen receptor α (ERα) is required for this proliferation and that estradiol treatment at the onset of HFD feeding is sufficient to drive it. This estrous influence on APC proliferation leads to increased obesity driven by adipocyte hyperplasia. These data indicate that estrogen drives ERα-dependent obesogenic adipocyte hyperplasia in females, exacerbating obesity and contributing to the differential fat distribution between the sexes.

Insulin increases placental triglyceride as a potential mechanism for fetal adiposity in maternal obesity.

OBJECTIVE: Maternal obesity increases the incidence of excess adiposity in newborns, resulting in lifelong diabetes risk. Elevated intrauterine fetal adiposity has been attributed to maternal hyperglycemia; however, this hypothesis does not account for the increased adiposity seen in newborns of mothers with obesity who have euglycemia. We aimed to explore the placental response to maternal hyperinsulinemia and the effect of insulin-like growth factor 2 (IGF-2) in promoting fetal adiposity by increasing storage and availability of nutrients to the fetus. METHODS: We used placental villous explants and isolated trophoblasts from normal weight and obese women to assess the effect of insulin and IGF-2 on triglyceride content and insulin receptor signaling. Stable isotope tracer methods were used ex vivo to determine effect of hormone treatment on de novo lipogenesis (DNL), fatty acid uptake, fatty acid oxidation, and esterification in the placenta. RESULTS: Here we show that placentae from euglycemic women with normal weight and obesity both have abundant insulin receptor. Placental depth and triglyceride were greater in women with obesity compared with normal weight women. In syncytialized placental trophoblasts and villous explants, insulin and IGF-2 activate insulin receptor, induce expression of lipogenic transcription factor SREBP-1 (sterol regulatory element-binding protein 1), and stimulate triglyceride accumulation. We demonstrate elevated triglyceride is attributable to increased esterification of fatty acids, without contribution from DNL and without an acceleration of fatty acid uptake. CONCLUSIONS: Our work reveals that obesity-driven aberrations in maternal metabolism, such as hyperinsulinemia, alter placental metabolism in euglycemic conditions, and may explain the higher prevalence of excess adiposity in the newborns of obese women.

Hyperinsulinemia induces early and dyssynchronous puberty in lean female mice.

Girls with obesity are at increased risk of early puberty. Obesity is associated with insulin resistance and hyperinsulinemia. We hypothesized that insulin plays a physiological role in pubertal transition, and super-imposed hyperinsulinemia due to childhood obesity promotes early initiation of puberty in girls. To isolate the effect of hyperinsulinemia from adiposity, we compared pre-pubertal and pubertal states in hyperinsulinemic, lean muscle (M)-insulin-like growth factor 1 receptor (IGF-1R)-lysine (K)-arginine (R) (MKR) mice to normoinsulinemic WT, with puberty onset defined by vaginal opening (VO). Our results show MKR had greater insulin resistance and higher insulin levels (P < 0.05) than WT despite lower body weight (P < 0.0001) and similar IGF-1 levels (P = NS). Serum luteinizing hormone (LH) levels were higher in hyperinsulinemic MKR (P = 0.005), and insulin stimulation induced an increase in LH levels in WT. VO was earlier in hyperinsulinemic MKR vs WT (P < 0.0001). When compared on the day of VO, kisspeptin expression was higher in hyperinsulinemic MKR vs WT (P < 0.05), and gonadotropin-releasing hormone and insulin receptor isoform expression was similar (P = NS). Despite accelerated VO, MKR had delayed, disordered ovarian follicle and mammary gland development. In conclusion, we found that hyperinsulinemia alone without adiposity triggers earlier puberty. In our study, hyperinsulinemia also promoted dyssynchrony between pubertal initiation and progression, urging future studies in girls with obesity to assess alterations in transition to adulthood.

Compromised endothelial function in transgender men taking testosterone.

CONTEXT: Transgender men (TGM) are persons assigned female gender at birth with a male gender identity and are routinely treated with testosterone. Androgen excess is associated with endothelial dysfunction among cisgender females (CGF) and is an early sign of atherosclerosis and hypertension. OBJECTIVE: To determine the effect of testosterone treatment on endothelial function in TGM. SETTING: The John B. Pierce Laboratory and Yale School of Medicine. SUBJECTS: Eleven TGM (age 27 ± 5 years; BMI 24.4 ± 3.7 kg/m2 ) receiving testosterone (T) and 20 CGF (28 ± 5 years; BMI 26.0 ± 5.1 kg/m2 ) during the early follicular phase of their menstrual cycle. DESIGN AND OUTCOME MEASURES: We evaluated brachial vasodilatory responses following stimuli designed to elicit shear stress using 5-minute occlusion to determine endothelial function (flow-mediated vasodilation, FMD). RESULTS: Total T was greater in the TGM compared to CGF (484.6 ± 122.5 vs 1.5 ± 0.7 ng/dL), as was free T (83.9 ± 32.4 vs 1.9 ± 0.8 pg/dL). FMD was markedly lower in the TGM (4.5 ± 2.7%) compared to the CGF (8.1 ± 2.9%, P = .002) indicating significantly diminished endothelial function in TGM. CONCLUSIONS: We have shown for the first time that in TGM the androgen-dominant hormonal milieu was associated with impaired endothelial function. Endothelial dysfunction precedes clinically detectable atherosclerotic plaque in the coronary arteries, so is an important marker for clinical cardiovascular risk. Therefore, attention to cardiovascular risk factors should be integral to the care of transgender men.

The Selective Progesterone Receptor Modulator Ulipristal Acetate Inhibits the Activity of the Glucocorticoid Receptor.

CONTEXT: The selective progesterone modulator ulipristal acetate (ulipristal) offers a much-needed therapeutic option for the clinical management of uterine fibroids. Although ulipristal initially passed safety evaluations in Europe, postmarketing analysis identified cases of hepatic injury and failure, leading to restrictions on the long-term use of ulipristal. One of the factors potentially contributing to significant side effects with the selective progesterone modulators is cross-reactivity with other steroid receptors. OBJECTIVE: To determine whether ulipristal can alter the activity of the endogenous glucocorticoid receptor (GR) in relevant cell types. DESIGN: Immortalized human uterine fibroid cells (UtLM) and hepatocytes (HepG2) were treated with the synthetic glucocorticoid dexamethasone and/or ulipristal. Primary uterine fibroid tissue was isolated from patients undergoing elective gynecological surgery and treated ex vivo with dexamethasone and/or ulipristal. In vivo ulipristal exposure was performed in C57Bl/6 mice to measure the effect on basal gene expression in target tissues throughout the body. RESULTS: Dexamethasone induced the expression of established glucocorticoid-target genes period 1 (PER1), FK506 binding protein 51 (FKBP5), and glucocorticoid-induced leucine zipper (GILZ) in UtLM and HepG2 cells, whereas cotreatment with ulipristal blocked the transcriptional response to glucocorticoids in a dose-dependent manner. Ulipristal inhibited glucocorticoid-mediated phosphorylation, nuclear translocation, and DNA interactions of GR. Glucocorticoid stimulation of PER1, FKBP5, and GILZ was abolished by cotreatment with ulipristal in primary uterine fibroid tissue. The expression of glucocorticoid-responsive genes was decreased in the lung, liver, and uterus of mice exposed to 2 mg/kg ulipristal. Interestingly, transcript levels of Fkbp5 and Gilz were increased in the hippocampus and pituitary. CONCLUSIONS: These studies demonstrate that ulipristal inhibits endogenous glucocorticoid signaling in human fibroid and liver cells, which is an important consideration for its use as a long-term therapeutic agent.

Reducing severe hypoglycaemia in hospitalised patients with diabetes: Early outcomes of standardised reporting and management.

BACKGROUND: Severe hypoglycaemic events (HGEs) in hospitalised patients are associated with poor outcomes and prolonged hospitalization. Systematic, coordinated care is required for acute management and prevention of HGEs; however, studies evaluating quality control efforts are scarce. OBJECTIVE: To investigate the effectiveness of system-based interventions to improve management response to HGEs. METHODS: System-based interventions were designed and implemented following a root cause analysis of HGE in adult patients with diabetes from two general medical wards with the highest incidence of HGE. Interventions included electronic medical record programming for a standardised order set for basal-bolus insulin regimen and hypoglycemia protocol, automated dextrose order, automated MD notification, and recommendation for endocrine consultation after two critical HGEs. The Pyxis MedStation was programmed to alert nurses to recheck blood glucose 15 min after the treatment. A card with the HGE management protocol was attached to each provider's ID badge and educational seminars were given to all providers. MAIN OUTCOMES AND MEASURES: Primary outcomes were to evaluate median time from HGE (glucose <50 mg/dL) to euglycemia (>100 mg/dL), and time from HGE to follow-up finger-stick (FS) testing preintervention and postintervention. Secondary outcomes were cumulative incidence of HGEs, recurrent hypoglycemia, rate of physician notification and use of standardised treatments among adults with diabetes on the two general medical wards. RESULTS: Among hospitalised adults with diabetes and HGE, median time from HGE to euglycemia declined from 225±46 min preintervention to 87±26 min postintervention (p=0.03). Median time from HGE to next FS testing also declined (76±14 min to 28±10 min, p<0.001). Standardised treatment administration for HGE improved significantly from 34% (12/35) to 97% (36/37); physician notification rate improved significantly from 51% (18/35) to 78% (29/37).Among hospitalised adults with diabetes, incidence of HGE decreased from 12% (35/295) over 3 months (preintervention period) to 6% (37/610) over 6 months (postintervention period) (p<0.001), while recurrent HGE did not show significant differences (37% (13/35) to 24% (9/37), p=0.09). CONCLUSIONS: System-based interventions had a clinically important impact on decreasing time from HGE to euglycemia and to next FS testing. This hypoglycemia bundle of care may be applied and tested in other community hospitals to improve patient safety.

Insulin Regulates Glycogen Synthesis in Human Endometrial Glands Through Increased GYS2.

Context: Glycogen synthesis is a critical metabolic function of the endometrium to prepare for successful implantation and sustain embryo development. Yet, regulation of endometrial carbohydrate metabolism is poorly characterized. Whereas glycogen synthesis is attributed to progesterone, we previously found that the metabolic B isoform of the insulin receptor is maximally expressed in secretory-phase endometrium, indicating a potential role of insulin in glucose metabolism. Objective: We sought to determine whether insulin or progesterone regulates glycogen synthesis in human endometrium. Design, Participants, Outcome Measurements: Endometrial epithelial cells were isolated from 28 healthy women and treated with insulin, medroxyprogesterone (MPA), or vehicle. Intracellular glycogen and the activation of key enzymes were quantified. Results: In epithelia, insulin induced a 4.4-fold increase in glycogen, whereas MPA did not alter glycogen content. Insulin inactivated glycogen synthase (GS) kinase 3α/ß (GSK3α/ß), relieving inhibition of GS. In a regulatory mechanism, distinct from liver and muscle, insulin also increased GS by 3.7-fold through increased GS 2 (GYS2) gene expression. Conclusions: We demonstrate that insulin, not progesterone, directly regulates glycogen synthesis through canonical acute inactivation of GSK3α/ß and noncanonical stimulation of GYS2 transcription. Persistently elevated GS enables endometrium to synthesize glycogen constitutively, independent of short-term nutrient flux, during implantation and early pregnancy. This suggests that insulin plays a key, physiological role in endometrial glucose metabolism and underlines the need to delineate the effect of maternal obesity and hyperinsulinemia on fertility and fetal development.

Ovarian Morphology by Transabdominal Ultrasound Correlates With Reproductive and Metabolic Disturbance in Adolescents With PCOS.

PURPOSE: To determine whether ovarian morphology imaged using transabdominal ultrasonography reflects clinical and metabolic features in adolescents with polycystic ovary syndrome (PCOS). METHODS: A retrospective pilot study was conducted in 33 adolescents (12-18 years) with PCOS as defined by hyperandrogenism and irregular cycles. Adolescents underwent the following assessments at a random time during the menstrual cycle: transabdominal ultrasonography, physical examination (height, weight, and systolic and diastolic blood pressure), fasting hormonal tests (free, percent free, and total testosterone, androstenedione, follicle stimulating hormone, luteinizing hormone), and metabolic tests (including an oral glucose tolerance test, fasting and 2-hour insulin and glucose, homeostatic model assessment of insulin resistance, and whole-body insulin sensitivity index). Ultrasound images were analyzed offline for ovarian area (OA), ovarian volume (OV), follicle number per cross section (FNPS), and follicle distribution pattern. Associations among endocrine and metabolic variables with sonographic features were assessed by Spearman's rank correlation coefficients and stepwise multiple linear regression. RESULTS: Total testosterone and androstenedione, but not free testosterone, or percent free testosterone, positively correlated with OA (ρ = .515, ρ = .422, respectively), OV (ρ = .451, ρ = .382), and FNPS (ρ = .394, ρ = .474). Luteinizing hormone:follicle stimulating hormone ratio also positively correlated with ovarian size (OA, ρ = .520 and OV, ρ = .409). Unexpectedly, body mass index (ρ = -.503) and fasting glucose levels (ρ = -.393) were inversely correlated with FNPS. Total testosterone was an independent predictor of FNPS, OA, and OV as judged by stepwise multiple regression analyses. CONCLUSIONS: Some aspects of ovarian morphology in adolescents with PCOS using transabdominal ultrasonography associate with markers of reproductive dysfunction and provide rationale to further investigate how ovarian morphology may reflect concurrent metabolic dysfunction.

Time course analysis of RNA quality in placenta preserved by RNAlater or flash freezing.

PROBLEM: Preservation of biospecimen quality is critical to accurately and reliably assessing genes and proteins. We evaluated the effect of preparation method and storage duration on RNA quality in placenta and decidua. METHOD OF STUDY: Aliquots of nine placentas and decidua were placed in RNAlater® (RL) or flash frozen (FF) within 30 minutes of delivery. RNA was extracted immediately (baseline) and from matched samples stored at -80°C for 1 and 8-10 months. RNA Integrity Number (RIN) and housekeeping gene expression were quantified. RESULTS: At both time points, RL placenta had RIN and housekeeping gene Ct values similar to baseline. However, FF placenta had significantly lower RIN and higher Ct values at 1 and 8-10 months. In RL and FF decidua, RIN was unchanged from baseline. CONCLUSION: We found RNAlater more effectively and consistently preserved placenta, compared to flash freezing. However, for decidua, which is less dense than placenta, both modes yielded comparable RNA integrity over time.

Endometrial Cancer-Associated FGF18 Expression Is Reduced by Bazedoxifene in Human Endometrial Stromal Cells In Vitro and in Murine Endometrium.

Endometrial cancer develops during exposure to estrogen unopposed by progesterone. Traditional formulations for menopausal hormone therapy include a progestin in women with a uterus. However, progestin exposure increases breast cancer risk in postmenopausal women. Alternatives to progestin include bazedoxifene (BZA), a selective estrogen receptor modulator, which prevents estrogen induced endometrial hyperplasia in clinical trials. Molecular mechanisms responsible for BZA's antiproliferative effect are not fully elucidated. We profiled endometrial adenocarcinoma, hyperplasia, and normal proliferative endometrium for differential expression in genes known to be regulated by estrogens or progesterone. Fibroblast growth factor (FGF)18, a paracrine growth factor promoting epithelial proliferation, was significantly increased in adenocarcinoma. Progesterone represses FGF18 by inducing heart and neural crest derivatives expressed transcript 2 (HAND2) in stromal cells. Notably, we confirmed lower HAND2 mRNA in adenocarcinoma, along with higher FGF tyrosine kinase receptor 2 and E74-like factor 5, collectively promoting FGF18 activity. We hypothesized BZA reduces epithelial proliferation by inhibiting FGF18 synthesis in stromal cells. To determine whether BZA regulates FGF18, we treated primary stromal cells with BZA or vehicle. In vitro, BZA reduced FGF18, but did not affect, HAND2. CD1 female mice received either BZA, conjugated estrogen (CE), or combined BZA/CE for 8 weeks. CE-treated mice had nearly 3-fold higher FGF18 expression. In contrast, BZA-treated mice, alone or with CE, had similar FGF18 as controls. Unexpectedly, BZA, alone or with CE, reduced HAND2 more than 80%, differing from progesterone regulation. Reduction of FGF18 is a potential mechanism by which BZA reduces endometrial proliferation and hyperplasia induced by estrogens. However, BZA works independently of HAND2, revealing a novel mechanism for progestin-free hormone therapy in postmenopausal women.

Differential Expression of IR-A, IR-B and IGF-1R in Endometrial Physiology and Distinct Signature in Adenocarcinoma.

CONTEXT: Type 2 diabetes and obesity are risk factors for endometrial hyperplasia and cancer, suggesting that hyperinsulinemia contributes to pathogenesis. Insulin action through insulin receptor (IR) splice variants IR-A and IR-B regulates cellular mitogenesis and metabolism, respectively. OBJECTIVE: We hypothesized that IR-A and IR-B are differentially regulated in normal endometrium, according to mitogenic and metabolic requirements through the menstrual cycle, as well as in endometrial hyperplasia and cancer. DESIGN: IR-A, IR-B, and IGF-1 receptor (IGF-1R) mRNA was quantified in endometrium, endometrial epithelial and stromal cells, and in vitro after hormone stimulation. SETTING: Academic center. PATIENTS: Endometrium was collected from women with regular cycles (n = 71), complex hyperplasia (n = 5), or endometrioid adenocarcinoma (n = 11). INTERVENTION(S): In vitro sex-steroid treatment. MAIN OUTCOME MEASURE(S): IR-A and IR-B expression Results: IR-A increased dramatically during the early proliferative phase, 20-fold more than IR-B. In early secretory phase, IR-B and IGF-1R expression increased, reaching maximal expression, whereas IR-A decreased. In adenocarcinoma, IR-B and IGF-1R expression was 5- to 6-fold higher than normal endometrium, whereas IR-A expression was similar to IR-B. Receptor expression was unrelated to body mass index. CONCLUSION: IR-A was elevated during the normal proliferative phase, and in endometrial hyperplasia and adenocarcinoma. The dramatic early rise of IR-A in normal endometrium indicates IR-A is the predominant isoform responsible for initial estrogen-independent endometrial proliferation as well as that of cancer. IR-B is elevated during the normal secretory phase when glucose uptake and glycogen synthesis support embryo development. Differing from other cancers, IR-B expression equals mitogenic IR-A in endometrial adenocarcinoma. Differential IR isoform expression suggests a distinct role for each in endometrial physiology and cancer.

Development of a Quantitative PCR Assay for Detection of Human Insulin-Like Growth Factor Receptor and Insulin Receptor Isoforms.

The biological activity of insulin and the insulin-like growth factor (IGF) ligands, IGF-I and IGF-II, is based in part on the relative abundance and distribution of their target receptors: the insulin receptor (IR) splice variants A (IR-A) and B (IR-B) and IGF 1 receptor (IGF-1R). However, the relative quantity of all three receptors in human tissues has never been measured together on the same scale. Due to the high homology between insulin receptor (IR)-A and IR-B proteins and lack of antibodies that discern the two IR splice variants, their mRNA sequence is the most reliable means of distinguishing between the receptors. Hence, highly specific primers for IR-A, IR-B, and IGF-1R mRNA were designed to accurately detect all three receptors by quantitative RT-PCR and enable direct quantification of relative receptor expression levels. A standard concentration curve of cDNA from each receptor was performed. Assay specificity was tested using competition assays and postamplification analysis by gel electrophoresis and cloning. Forward and reverse primer concentrations were optimized to ensure equal efficiencies across primer pairs. This assay enables a specific molecular signature of IGF/insulin signaling receptors to be assayed in different tissues, cell types, or cancers.

H19 lncRNA alters stromal cell growth via IGF signaling in the endometrium of women with endometriosis.

Endometriosis affects approximately 15% of reproductive aged women and is associated with chronic pelvic pain and infertility. However, the molecular mechanisms by which endometriosis impacts fertility are poorly understood. The developmentally regulated, imprinted H19 long noncoding RNA (lncRNA) functions to reduce the bioavailability of microRNA let-7 by acting as a molecular sponge. Here we report that H19 expression is significantly decreased in the eutopic endometrium of women with endometriosis as compared to normal controls. We show that decreased H19 increases let-7 activity, which in turn inhibits Igf1r expression at the post-transcriptional level, thereby contributing to reduced proliferation of endometrial stromal cells. We propose that perturbation of this newly identified H19/Let-7/IGF1R regulatory pathway may contribute to impaired endometrial preparation and receptivity for pregnancy in women with endometriosis. Our finding represents the first example of a lncRNA-based mechanism in endometriosis and its associated infertility, thus holding potential in the development of novel therapeutics for women with endometriosis and infertility.

Glucose and metformin modulate human first trimester trophoblast function: a model and potential therapy for diabetes-associated uteroplacental insufficiency.

PROBLEM: Diabetes confers an increased risk of preeclampsia, but its pathogenic role in preeclampsia is poorly understood. The objective of this study was to elucidate the effects of excess glucose on trophoblast function and whether any changes could be reversed by metformin. METHOD OF STUDY: The human first trimester trophoblast cell line (Sw.71) was treated with glucose at 5, 10, 25, and 50 mm, in the presence and absence of metformin. Trophoblast migration was quantified and supernatant cytokine, chemokine, and angiogenic factors measured. RESULTS: Increasing concentrations of glucose significantly increased trophoblast secretion of the inflammatory cytokines/chemokines: IL-1ß, IL-6, IL-8, GRO-α, RANTES, and G-CSF; significantly increased trophoblast secretion of the anti-angiogenic factors sFlt-1 and sEndoglin; and significantly decreased trophoblast migration. Excess glucose-induced trophoblast IL-1ß production was inhibited by disabling the Nalp3/ASC inflammasome. Metformin partially reduced the glucose-induced inflammatory response, but had no effect on the anti-angiogenic or antimigratory response. CONCLUSION: Excess glucose induced a pro-inflammatory, anti-angiogenic, and antimigratory state in first trimester trophoblast cells. Glucose-induced trophoblast IL-1ß secretion was mediated by the inflammasome. Glucose-induced inflammation was partially reversed by metformin. These findings demonstrate the pleiotropic effects of hyperglycaemia on the trophoblast, providing potential explanations for the strong link between diabetes and preeclampsia.

The H19/let-7 double-negative feedback loop contributes to glucose metabolism in muscle cells.

The H19 lncRNA has been implicated in development and growth control and is associated with human genetic disorders and cancer. Acting as a molecular sponge, H19 inhibits microRNA (miRNA) let-7. Here we report that H19 is significantly decreased in muscle of human subjects with type-2 diabetes and insulin resistant rodents. This decrease leads to increased bioavailability of let-7, causing diminished expression of let-7 targets, which is recapitulated in vitro where H19 depletion results in impaired insulin signaling and decreased glucose uptake. Furthermore, acute hyperinsulinemia downregulates H19, a phenomenon that occurs through PI3K/AKT-dependent phosphorylation of the miRNA processing factor KSRP, which promotes biogenesis of let-7 and its mediated H19 destabilization. Our results reveal a previously undescribed double-negative feedback loop between sponge lncRNA and target miRNA that contributes to glucose regulation in muscle cells.

mRNA-binding protein TIA-1 reduces cytokine expression in human endometrial stromal cells and is down-regulated in ectopic endometrium.

BACKGROUND: Cytokines and growth factors play important roles in endometrial function and the pathogenesis of endometriosis. mRNAs encoding cytokines and growth factors undergo rapid turnover; primarily mediated by adenosine- and uridine-rich elements (AREs) located in their 3'-untranslated regions. T-cell intracellular antigen (TIA-1), an mRNA-binding protein, binds to AREs in target transcripts, leading to decreased gene expression. OBJECTIVE: The purpose of this article was to determine whether TIA-1 plays a role in the regulation of endometrial cytokine and growth factor expression during the normal menstrual cycle and whether TIA-1 expression is altered in women with endometriosis. METHODS: Eutopic endometrial tissue obtained from women without endometriosis (n = 30) and eutopic and ectopic endometrial tissues from women with endometriosis (n = 17) were immunostained for TIA-1. Staining intensities were evaluated by histological scores (HSCOREs). The regulation of endometrial TIA-1 expression by immune factors and steroid hormones was studied by treating primary cultured human endometrial stromal cells (HESCs) with vehicle, lipopolysaccharide, TNF-α, IL-6, estradiol, or progesterone, followed by protein blot analyses. HESCs were engineered to over- or underexpress TIA-1 to test whether TIA-1 regulates IL-6 or TNF-α expression in these cells. RESULTS: We found that TIA-1 is expressed in endometrial stromal and glandular cells throughout the menstrual cycle and that this expression is significantly higher in the perimenstrual phase. In women with endometriosis, TIA-1 expression in eutopic and ectopic endometrium was reduced compared with TIA-1 expression in eutopic endometrium of unaffected control women. Lipopolysaccharide and TNF-α increased TIA-1 expression in HESCs in vitro, whereas IL-6 or steroid hormones had no effect. In HESCs, down-regulation of TIA-1 resulted in elevated IL-6 and TNF-α expression, whereas TIA-1 overexpression resulted in decreased IL-6 and TNF-α expression. CONCLUSIONS: Endometrial TIA-1 is regulated throughout the menstrual cycle, TIA-1 modulates the expression of immune factors in endometrial cells, and downregulation of TIA-1 may contribute to the pathogenesis of endometriosis.

Polycystic ovary syndrome in adolescence: impaired glucose tolerance occurs across the spectrum of BMI.

CONTEXT: Polycystic ovary syndrome (PCOS) is a chronic condition with metabolic manifestations spanning the reproductive years. OBJECTIVE: We sought to examine glucose metabolism, irrespective of the presence of obesity in a cohort of adolescent girls with PCOS. DESIGN: One hundred adolescents were assessed for PCOS in a multi-specialty adolescent PCOS program. PCOS was diagnosed by Androgen Excess Society criteria. Oral glucose tolerance testing (OGTT), homeostatic model assessment of insulin resistance, and androgen and lipid profiles were performed for those meeting criteria. RESULTS: Sixty-six adolescents (mean age 15.8 ± 0.2 yrs, range 13.0-18.6) had confirmed PCOS, and were eligible for inclusion in our analysis. Abnormal glucose metabolism was present in 12 of 66 (18.2%) subjects: 2 (3.0%) impaired fasting glucose, 10 (15.2%) impaired glucose tolerance (IGT), and 1 (1.5%) type 2 diabetes. IGT was the most common abnormality, occurring with equal frequency in obese (OB, mean body mass index (BMI) 36.9 ± 0.8 kg/m(2) ) and non-obese (NOB, mean BMI 24.5 ± 0.6 kg/m(2) ) adolescents (p = 0.3). In a subgroup analysis, NOB adolescents with IGT (NOB-IGT) had similar mean 2-h insulin, high density lipoprotein, C-reactive protein, and testosterone levels to the OB cohort despite marked differences in BMI (p < 0.001) and % body fat (p = 0.002). However, the NOB-IGT group had a lower mean fasting insulin level than the OB cohort (p = 0.04). CONCLUSION: Abnormal glucose metabolism is highly prevalent in adolescents with PCOS. In particular, IGT occurs across the spectrum of BMI. A screening OGTT should be considered for adolescents diagnosed with PCOS, independently of their BMI.

Skeletal muscle insulin resistance promotes increased hepatic de novo lipogenesis, hyperlipidemia, and hepatic steatosis in the elderly.

Aging is closely associated with muscle insulin resistance, hyperlipidemia, nonalcoholic fatty liver disease (NAFLD), and type 2 diabetes. We examined the hypothesis that muscle insulin resistance in healthy aging promotes increased hepatic de novo lipogenesis (DNL) and hyperlipidemia by altering the distribution pattern of postprandial energy storage. Healthy, normal weight, sedentary elderly subjects pair-matched to young subjects were given two high-carbohydrate meals followed by ¹³C/¹H magnetic resonance spectroscopy measurements of postprandial changes in muscle and liver glycogen and lipid content, and assessment of DNL using ²H2O. Net muscle glycogen synthesis was reduced by 45% (P < 0.007) in the elderly subjects compared with the young, reflecting severe muscle insulin resistance. Net liver glycogen synthesis was similar between groups (elderly, 143 ± 23 mmol/L vs. young, 138 ± 13 mmol/L; P = NS). Hepatic DNL was more than twofold higher in the elderly than in the young subjects (elderly, 14.5 ± 1.4% vs. young, 6.9 ± 0.7%; P = 0.00015) and was associated with approximately threefold higher postprandial hepatic triglyceride (TG) content (P < 0.005) and increased fasting plasma TGs (elderly, 1.19 ± 0.18 mmol/L vs. young, 0.74 ± 0.11 mmol/L; P = 0.02). These results strongly support the hypothesis that muscle insulin resistance in aging promotes hyperlipidemia and NAFLD by altering the pattern of postprandial carbohydrate storage away from muscle glycogen and into hepatic DNL.

Reversal of muscle insulin resistance with exercise reduces postprandial hepatic de novo lipogenesis in insulin resistant individuals.

Skeletal muscle insulin resistance has been implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and atherogenic dyslipidemia associated with the metabolic syndrome by altering the distribution pattern of postprandial energy storage. We conducted a study to examine this hypothesis by reversing muscle insulin resistance with a single bout of exercise and measuring hepatic de novo lipogenesis and hepatic triglyceride synthesis after a carbohydrate-rich meal. We studied 12 healthy, young, lean, insulin resistant individuals in an interventional, randomized cross-over trial. The response to the ingestion of a carbohydrate-rich meal was studied at rest and after one 45-min bout of exercise on an elliptical trainer. Hepatic de novo lipogenesis was assessed by using (2)H(2)O, and changes in glycogen and fat content in liver and muscle were measured by (13)C and (1)H magnetic resonance spectroscopy, respectively. Exercise resulted in a greater than threefold increase in postprandial net muscle glycogen synthesis (P < 0.001), reflecting improved muscle insulin responsiveness, and a ≈40% reduction (P < 0.05) in net hepatic triglyceride synthesis. These changes in whole body energy storage were accompanied by a ≈30% decrease in hepatic de novo lipogenesis (P < 0.01) and were independent of changes in fasting or postprandial plasma glucose and insulin concentrations. These data demonstrate that skeletal muscle insulin resistance is an early therapeutic target for the treatment and prevention of atherogenic dyslipidemia and NAFLD in young insulin resistant individuals who are prone to develop the metabolic syndrome and type 2 diabetes.

Prevention of hepatic steatosis and hepatic insulin resistance by knockdown of cAMP response element-binding protein.

In patients with poorly controlled type 2 diabetes mellitus (T2DM), hepatic insulin resistance and increased gluconeogenesis contribute to fasting and postprandial hyperglycemia. Since cAMP response element-binding protein (CREB) is a key regulator of gluconeogenic gene expression, we hypothesized that decreasing hepatic CREB expression would reduce fasting hyperglycemia in rodent models of T2DM. In order to test this hypothesis, we used a CREB-specific antisense oligonucleotide (ASO) to knock down CREB expression in liver. CREB ASO treatment dramatically reduced fasting plasma glucose concentrations in ZDF rats, ob/ob mice, and an STZ-treated, high-fat-fed rat model of T2DM. Surprisingly, CREB ASO treatment also decreased plasma cholesterol and triglyceride concentrations, as well as hepatic triglyceride content, due to decreases in hepatic lipogenesis. These results suggest that CREB is an attractive therapeutic target for correcting both hepatic insulin resistance and dyslipidemia associated with nonalcoholic fatty liver disease (NAFLD) and T2DM.