Longitudinal changes in adipokines and free leptin index during and after pregnancy in women with obesity.

OBJECTIVE: Detailed data on adipokines and body composition during and after pregnancy in women of different BMI categories are lacking. Furthermore, adipokine regulation during pregnancy and the factors contributing to gestational insulin resistance are not completely understood. The objective was to longitudinally determine adipokine levels, body composition, and insulin sensitivity during and after pregnancy in women of healthy weight (HW) and with obesity (OB), and identify factors associated with insulin resistance. DESIGN: Women (30 HW, 19 OB) underwent blood sampling and body composition examination, by air-displacement plethysmography, longitudinally during pregnancy (trimesters 1, 2, 3) and after pregnancy (6, 12, 18 months postpartum). Serum leptin, soluble leptin receptor (sOB-R), and adiponectin levels were measured and free leptin index (FLI) and homeostatic model assessment of insulin resistance (HOMA-IR) determined. RESULTS: Fat mass and leptin increased during pregnancy in the HW (p < 0.01) but not in the OB group. sOB-R increased during pregnancy in both groups (p < 0.001). Thus, FLI was unchanged in HW throughout pregnancy but reduced in OB (p = 0.001), although consistently higher in OB. Adiponectin decreased in both groups during pregnancy (p < 0.001 for HW, p = 0.01 for OB). After pregnancy, adiponectin increased in both groups, but more markedly in OB where it reached trimester 1 levels. Multivariable regression identified FLI as the variable most strongly associated with HOMA-IR in all trimesters, but not after pregnancy. CONCLUSIONS: Leptin, sOB-R, adiponectin, and FLI undergo marked changes during and after pregnancy with differences in women of different BMI. We suggest that leptin activity is regulated by its soluble receptor and that this is an important factor for optimizing fat mass and insulin sensitivity during pregnancy.

Adiponectin, chemerin, cytokines, and dipeptidyl peptidase 4 are released from human adipose tissue in a depot-dependent manner: an in vitro system including human serum albumin.

BACKGROUND: Adipose tissue (AT) contributes to metabolic dysfunction through imbalanced production of adipokines, including cytokines. Visceral AT in particular is associated with metabolic disorders, indicating a specific secretory status. The relative significance of different human AT depots in adipokine release is not fully known. Further, previous in vitro systems usually included medium containing bovine serum albumin (BSA), which may induce cytokine release. Our aim was to compare release of a number of adipokines/cytokines - all implicated in insulin resistance - from human subcutaneous and visceral AT in a short-term incubation system minimizing cytokine induction and including repeated measurements during 24 h. A prerequisite was to evaluate a potential alternative to BSA in the incubation medium. METHODS: Subcutaneous and/or visceral AT from 17 patients (age 20-68 years; BMI 22.6-56.7 kg/m2) undergoing elective surgery was incubated for 2, 4, 6, 8, and 24 h in medium with or without 1% BSA or human serum albumin (HSA). Medium concentrations of adiponectin, chemerin, nine cytokines, dipeptidyl peptidase 4 (DPP4), and omentin were analyzed by multiplex immunoassay or ELISA. Adipocyte size, AT macrophage density, and medium concentrations of endotoxin were determined. RESULTS: Cytokine release was induced by BSA but not by HSA. In evaluation of the final incubation protocol including 1% HSA, and as expected, adiponectin release was higher from subcutaneous biopsies of nonobese than of obese subjects and inversely associated with adipocyte size; omentin was released almost exclusively from visceral AT. Exploratory incubations revealed more abundant release of chemerin, cytokines (except IL-6), and DPP4 from the visceral depot, while adiponectin release was higher from subcutaneous than visceral AT. Release was linear for a maximum of 2-6 h. Macrophage density was higher in visceral than subcutaneous AT. Levels of endotoxin in the medium were negligible. CONCLUSIONS: Adiponectin, chemerin, many cytokines, and DPP4 are released from human AT in a depot-dependent manner. These results highlight functional differences between visceral and subcutaneous AT, and a mechanistic link between regional fat accumulation and metabolic disorders. Supplementation of human AT incubation medium with HSA rather than BSA is recommended to minimize induction of cytokine release.

Inflammatory and metabolic markers in relation to outcome of in vitro fertilization in a cohort of predominantly overweight and obese women.

For overweight and obese women undergoing in vitro fertilization (IVF) the pregnancy and live birth rates are compromised while the underlying mechanisms and predictors are unclear. The aim was to explore the association between adipose tissue-related inflammatory and metabolic markers and the pregnancy and live birth outcome of IVF in a cohort of predominantly overweight and obese women. Serum samples, fulfilling standardizing criteria, were identified from 195 women having participated in either the control (n = 131) or intervention (n = 64) group of a randomized controlled trial (RCT), seeking to evaluate the effect of a weight reduction intervention on IVF outcome in obese women. Serum high-sensitivity C-reactive protein (hsCRP) and the adipokines leptin and adipocyte fatty acid-binding protein (AFABP) were analyzed for the whole cohort (n = 195) in samples collected shortly before IVF [at randomization (control group), after intervention (intervention group)]. Information on age, anthropometry [BMI, waist circumference, waist-to-height ratio (WHtR)], pregnancy and live birth rates after IVF, as well as the spontaneous pregnancy rate, was extracted or calculated from collected data. The women of the original intervention group were also characterized at randomization regarding all variables. Eight women [n = 3 original control group (2.3%), n = 5 original intervention group (7.8%)] conceived spontaneously before starting IVF. BMI category proportions in the cohort undergoing IVF (n = 187) were 1.6/20.1/78.3% (normal weight/overweight/obese). The pregnancy and live birth rates after IVF for the cohort were 35.8% (n = 67) and 24.6% (n = 46), respectively. Multivariable logistic regression revealed that none of the variables (age, hsCRP, leptin, AFABP, BMI, waist circumference, WHtR) were predictive factors of pregnancy or live birth after IVF. Women of the original intervention group displayed reductions in hsCRP, leptin, and anthropometric variables after intervention while AFABP was unchanged. In this cohort of predominantly overweight and obese women undergoing IVF, neither low-grade inflammation, in terms of hsCRP, other circulating inflammatory and metabolic markers released from adipose tissue (leptin, AFABP), nor anthropometric measures of adiposity or adipose tissue distribution (BMI, waist, WHtR) were identified as predictive factors of pregnancy or live birth rate.Trial registration: ClinicalTrials.gov number, NCT01566929. Trial registration date 30-03-2012, retrospectively registered.

Adipocyte size predicts incidence of type 2 diabetes in women.

Enlarged subcutaneous abdominal adipocytes have been shown to predict incidence of type 2 diabetes (T2D) in the Pima population of Arizona (USA). We investigated the role of subcutaneous abdominal adipocyte size (AAS), as well as femoral adipocyte size (FAS), as predictors of T2D in a population-based Swedish cohort. In 1974-1975, a sample of 1302 middle-aged women underwent a health examination, including anthropometry and evaluation of parental medical history. In addition, body composition (total body potassium and total body water), AAS and FAS (adipose tissue needle biopsy) were assessed in a subsample of 245 women. Incidence of T2D was followed until 2001, with 36 cases eligible for inclusion in this analysis. Women developing T2D had larger AAS at baseline vs. women remaining healthy (age/heredity-adjusted hazard ratio for increase of AAS by 1 sd [AAS-HR] 1.91; P<0.001). Further adjustment for both body fat percentage and waist-to-height ratio (WHtR) indicated a robust association. For FAS, the corresponding associations were consistently weaker. WHtR retained a strong predictive association independent of AAS and FAS (WHtR-HR 2.6 and 2.7, respectively; P<0.001). To conclude, in addition to the amount and distribution of body fat in women, subcutaneous adipocyte size, particularly in the abdominal region, predicts incidence of T2D in later life.

Intense electroacupuncture normalizes insulin sensitivity, increases muscle GLUT4 content, and improves lipid profile in a rat model of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is associated with hyperandrogenism and insulin resistance, possibly reflecting defects in skeletal muscle and adipocyte insulin signaling. Low-frequency (2 Hz) electroacupuncture (EA) increases insulin sensitivity in female rats with dihydrotestosterone (DHT)-induced PCOS, but the mechanism is unclear. We hypothesized that low-frequency EA regulates mediators involved in skeletal muscle glucose uptake and metabolism and alters the lipid profile in rats with DHT-induced PCOS. To test this hypothesis, we implanted in prepubescent female rats 90-day continuous-release pellets containing DHT (PCOS). At 70 days of age, the rats were randomly subdivided into two groups: one received low-frequency EA (evoking muscle twitches) for 20-25 min five times/wk for 4-5 wk; the other did not. Controls were implanted with pellets containing vehicle only. All three groups were otherwise handled similarly. Lipid profile was measured in fasting blood samples. Insulin sensitivity was determined by euglycemic hyperinsulinemic clamp, soleus muscle protein expression of glucose transporter 4 (GLUT4), and phosphorylated and nonphosphorylated Akt, and Akt substrate of 160 kDa was determined by Western blot analysis and GLUT4 location by immunofluorescence staining. PCOS EA rats had normalized insulin sensitivity, lower levels of total high-density lipoprotein and low-density lipoprotein cholesterol, and increased expression of GLUT4 in different compartments of skeletal muscle compared with PCOS rats. Total weight and body composition did not differ in the groups. Thus, in rats with DHT-induced PCOS, low-frequency EA has systemic and local effects involving intracellular signaling pathways in muscle that may, at least in part, account for the marked improved insulin sensitivity.

Low-frequency electro-acupuncture and physical exercise improve metabolic disturbances and modulate gene expression in adipose tissue in rats with dihydrotestosterone-induced polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, abdominal obesity, and insulin resistance. Pharmacotherapy is often unsatisfactory. This study evaluates the effects of low-frequency electro-acupuncture (EA) and physical exercise on metabolic disturbances and adipose tissue mRNA expression of selected genes in a rat PCOS model characterized by insulin resistance and adiposity. Dihydrotestosterone (inducing PCOS) or vehicle (control) was administrated continuously, beginning before puberty. At age 10 wk, PCOS rats were randomly divided into three groups; PCOS, PCOS EA, and PCOS exercise. PCOS EA rats received 2-Hz EA (evoking muscle twitches) three times/wk during 4-5 wk. PCOS exercise rats had free access to a running wheel for 4-5 wk. EA and exercise improved insulin sensitivity, measured by clamp, in PCOS rats. Exercise also reduced adiposity, visceral adipocyte size, and plasma leptin. EA increased plasma IGF-I. Real-time RT-PCR revealed increased expression of leptin and IL-6 and decreased expression of uncoupling protein 2 in visceral adipose tissue of PCOS rats compared with controls. EA restored the expression of leptin and uncoupling protein 2, whereas exercise normalized adipose tissue leptin and IL-6 expression in PCOS rats. Thus, EA and exercise ameliorate insulin resistance in rats with PCOS. This effect may involve regulation of adipose tissue metabolism and production because EA and exercise each partly restore divergent adipose tissue gene expression associated with insulin resistance, obesity, and inflammation. In contrast to exercise, EA improves insulin sensitivity and modulates adipose tissue gene expression without influencing adipose tissue mass and cellularity.

Heterogeneous glycosylation patterns of human PAI-1 may reveal its cellular origin.

The main inhibitor of intravascular fibrinolysis is plasminogen activator inhibitor 1 (PAI-1) which binds to and irreversibly inhibits tissue plasminogen activator (tPA). PAI-1 is present in blood, both in platelets and in plasma, and PAI-1 levels are associated with risk of atherothrombosis. Several tissues express PAI-1 but the source of plasma PAI-1 is not known. We recently found that platelets can de novo synthesize PAI-1 and the amount synthesized in vitro in 24 hours is 35-fold higher than required to maintain normal plasma levels. Recombinant human PAI-1 expressed in different cell types or secreted naturally by human cell lines, exhibit heterogeneous glycosylation patterns. The aim of this study was to investigate the hypothesis that platelets might be the source of plasma PAI-1 and that the cellular source of PAI-1 can be determined by its tissue-specific glycosylation pattern. PAI-1 was isolated from platelets, macrophages, endothelial cells, adipose tissue, as well as plasma from lean and obese subjects. The glycosylation was analyzed by nanoLC-MS/MS. PAI-1 isolated from cell lysates and conditioned media from macrophages, endothelial cells, and adipose tissue expressed heterogeneous glycosylation patterns. By contrast, no glycans were detected on PAI-1 isolated from plasma or platelets from healthy lean individuals. Hence, our data suggest that platelets may be the main source of plasma PAI-1 in lean individuals. Interestingly, plasma PAI-1 from obese subjects had a glycan composition similar to that of adipose tissue suggesting that obese subjects with elevated PAI-1 levels may have a major contribution from other tissues.

Free lipid and computerized determination of adipocyte size.

The size distribution of adipocytes in a suspension, after collagenase digestion of adipose tissue, can be determined by computerized image analysis. Free lipid, forming droplets, in such suspensions implicates a bias since droplets present in the images may be identified as adipocytes. This problem is not always adjusted for and some reports state that distinguishing droplets and cells is a considerable problem. In addition, if the droplets originate mainly from rupture of large adipocytes, as often described, this will also bias size analysis. We here confirm that our ordinary manual means of distinguishing droplets and adipocytes in the images ensure correct and rapid identification before exclusion of the droplets. Further, in our suspensions, prepared with focus on gentle handling of tissue and cells, we find no association between the amount of free lipid and mean adipocyte size or proportion of large adipocytes.

Adipose tissue and body composition in women six years after gestational diabetes: factors associated with development of type 2 diabetes.

Factors differentiating women at highest risk of progression to type 2 diabetes mellitus (T2DM) after gestational diabetes mellitus (GDM) are incompletely known. Our aim was to characterize adipose tissue and body composition in relation to glucose metabolism in women with a history of GDM and to identify factors associated with development of T2DM. We examined glucose tolerance (OGTT), insulin sensitivity (HOMA-IR), body composition (anthropometry, air displacement plethysmography), and blood chemistry in 39 women 6 years after GDM. An adipose tissue biopsy was obtained to assess the size, number, and lipolytic activity of adipocytes, and adipokine release and density of immune cells and blood vessels in adipose tissue. Normal glucose tolerance (NGT) was identified in 31 women and impaired glucose metabolism (IGM) in 8. Women with IGM had higher BMI/fat mass, and related expected adipose tissue features, than women with NGT. Ethnicity was similar in the groups, but numerically there was a higher proportion of European women in the NGT group and a higher proportion of non-European women in the IGM group. BMI was the best discriminator of NGT versus IGM (multivariable logistic regression: OR = 1.34, P < 0.01). Waist-to-height ratio and adipocyte volume were most strongly associated with HOMA-IR (multivariable linear regression: R2 = 0.656, P < 0.001). After adjustment for BMI/ethnicity, women with IGM had increased serum adipocyte fatty acid-binding protein, weight gain after index pregnancy, and a lower proportion of fat-free mass. These factors, together with high BMI, abdominal fat distribution, and enlarged adipocytes, may increase the risk of progression to T2DM after GDM.

A new rat model exhibiting both ovarian and metabolic characteristics of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder associated with ovulatory dysfunction, hyperandrogenism, abdominal obesity, and insulin resistance. However, its etiology is unclear, and its management is often unsatisfactory or requires a diversified approach. Here, we describe a new rat PCOS model, the first to exhibit both ovarian and metabolic characteristics of the syndrome. Female rats received the nonaromatizable androgen dihydrotestosterone (DHT) or the aromatase inhibitor letrozole by continuous administration, beginning before puberty, to activate androgen receptors. Adult DHT rats had irregular cycles, polycystic ovaries characterized by cysts formed from atretic follicles, and a diminished granulosa layer. They also displayed metabolic features, including increased body weight, increased body fat, and enlarged mesenteric adipocytes, as well as elevated leptin levels and insulin resistance. All letrozole rats were anovulatory and developed polycystic ovaries with structural changes strikingly similar to those in human PCOS. Our findings suggest that the formation of a "hyperplastic" theca interna reflects the inclusion of luteinized granulosa cells in the cyst wall rather than true hyperplasia. We conclude that the letrozole model is suitable for studies of the ovarian features of human PCOS, while the DHT model is suitable for studies of both ovarian and metabolic features of the syndrome.

Postnatal testosterone exposure results in insulin resistance, enlarged mesenteric adipocytes, and an atherogenic lipid profile in adult female rats: comparisons with estradiol and dihydrotestosterone.

Postnatal events contribute to features of the metabolic syndrome in adulthood. In this study, postnatally administered testosterone reduced insulin sensitivity and increased the mesenteric fat depot, the size of mesenteric adipocytes, serum levels of total cholesterol, low-density lipoprotein cholesterol, and triglycerides, and the atherogenic index in adult female rats. To assess the involvement of estrogen and androgen receptors in these programming effects, we compared testosterone-exposed rats to rats exposed to estradiol or dihydrotestosterone (DHT). Estradiol-treated rats had lower insulin sensitivity than testosterone-treated rats and, like those rats, had enlarged mesenteric adipocytes and increased triglyceride levels. DHT also reduced insulin sensitivity but did not mimic the other metabolic effects of testosterone. All treated rats were probably anovulatory, but only those treated with testosterone had reduced testosterone levels. This study confirms our previous finding that postnatal administration of testosterone reduces insulin sensitivity in adult female rats and shows that this effect is accompanied by unfavorable changes in mesenteric fat tissue and in serum lipid levels. The findings in the estradiol and DHT groups suggest that estrogen receptors exert stronger metabolic programming effects than androgen receptors. Thus, insults such as sex hormone exposure in early life may have long-lasting effects, thereby creating a predisposition to disturbances in insulin sensitivity, adipose tissue, and lipid profile in adulthood.

The expression of NAD(P)H:quinone oxidoreductase 1 is high in human adipose tissue, reduced by weight loss, and correlates with adiposity, insulin sensitivity, and markers of liver dysfunction.

CONTEXT: We have previously identified nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1 (NQO1), an enzyme involved in the protection against oxidative stress, as a gene predominantly expressed in human adipocytes. Studies in mice deficient in NQO1 activity suggest that NQO1 may also play an important role in metabolism. OBJECTIVE: The aim of this study was to explore the expression and regulation of NQO1 in human adipose tissue (AT) and isolated adipocytes. PATIENTS AND RESULTS: The high expression of NQO1 in adipocytes was verified in human adipocytes and AT by real-time PCR. DNA microarray analysis showed that NQO1 was expressed at higher levels in large compared with small adipocytes, isolated from the same fat biopsy. Furthermore, NQO1 mRNA levels were positively correlated with adipocyte size (n = 7; P < 0.002). During an 18-wk diet regime (n = 24; mean weight loss 27 kg), the NQO1 expression in human sc AT was down-regulated (P < 0.0001), and mRNA levels correlated with body mass index (P = 0.0005), sc, and total abdominal AT areas, as determined by computerized tomography (P < 0.0001, both) and metabolic parameters. NQO1 mRNA levels were also positively correlated with aspartate aminotransferase (P = 0.0028) and alanine aminotransferase (P = 0.0219), markers known to be associated with severity of hepatic steatosis. CONCLUSIONS: NQO1 is highly expressed in human AT, particularly in large adipocytes. AT NQO1 expression is reduced during diet-induced weight loss, and the expression levels positively correlate with adiposity, glucose tolerance, and markers of liver dysfunction. Together, these findings indicate a role for NQO1 in the metabolic complications of human obesity.

Separation of human adipocytes by size: hypertrophic fat cells display distinct gene expression.

Enlarged adipocytes are associated with insulin resistance and are an independent predictor of type 2 diabetes. To understand the molecular link between these diseases and adipocyte hypertrophy, we developed a technique to separate human adipocytes from an adipose tissue sample into populations of small cells (mean 57.6+/-3.54 microm) and large cells (mean 100.1+/-3.94 microm). Microarray analysis of the cell populations separated from adipose tissue from three subjects identified 14 genes, of which five immune-related, with more than fourfold higher expression in large cells than small cells. Two of these genes were serum amyloid A (SAA) and transmembrane 4 L six family member 1 (TM4SF1). Real-time RT-PCR analysis of SAA and TM4SF1 expression in adipocytes from seven subjects revealed 19-fold and 22-fold higher expression in the large cells, respectively, and a correlation between adipocyte size and both SAA and TM4SF1 expression. The results were verified using immunohistochemistry. In comparison with 17 other human tissues and cell types by microarray, large adipocytes displayed by far the highest SAA and TM4SF1 expression. Thus, we have identified genes with markedly higher expression in large, compared with small, human adipocytes. These genes may link hypertrophic obesity to insulin resistance/type 2 diabetes.

A new approach to measuring vitamin D in human adipose tissue using time-of-flight secondary ion mass spectrometry: a pilot study.

Circulating concentrations of vitamin D, 25(OH)D, and 1,25(OH)2D are lower in obese than lean individuals, but little is known about the adipose tissue content of these molecules. The aim of this study was to explore the possibility to use time-of-flight secondary ion mass spectrometry (TOF-SIMS) to measure vitamin D and its metabolites in fat tissue in obese and lean subjects. Abdominal subcutaneous adipose tissue (SAT) biopsies were obtained from three lean and three obese women, and paired biopsies SAT and visceral adipose tissue (VAT) were obtained from three obese subjects during gastric bypass surgery. TOF-SIMS was used to measure vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in adipose tissue. We found that vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in adipose tissue can be measured with TOF-SIMS. In adipose tissue, vitamin D3 and its metabolites were located in adipocyte lipid droplets. The content of vitamin D3 (P=0.006) and 25(OH)D3 (P=0.018) were lower in SAT in obese compared with lean women. TOF-SIMS has the potential to semi-quantitatively measure vitamin D metabolites in adipose tissue, and offers a possibility to compare vitamin D levels in different depots and groups of individuals. It also gives the opportunity to explore the localization of vitamin D metabolites at a cellular level.

Electrical vs manual acupuncture stimulation in a rat model of polycystic ovary syndrome: different effects on muscle and fat tissue insulin signaling.

In rats with dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS), repeated low-frequency electrical stimulation of acupuncture needles restores whole-body insulin sensitivity measured by euglycemic hyperinsulinemic clamp. We hypothesized that electrical stimulation causing muscle contractions and manual stimulation causing needle sensation have different effects on insulin sensitivity and related signaling pathways in skeletal muscle and adipose tissue, with electrical stimulation being more effective in DHT-induced PCOS rats. From age 70 days, rats received manual or low-frequency electrical stimulation of needles in abdominal and hind limb muscle five times/wk for 4-5 wks; controls were handled but untreated rats. Low-frequency electrical stimulation modified gene expression (decreased Tbc1d1 in soleus, increased Nr4a3 in mesenteric fat) and protein expression (increased pAS160/AS160, Nr4a3 and decreased GLUT4) by western blot and increased GLUT4 expression by immunohistochemistry in soleus muscle; glucose clearance during oral glucose tolerance tests was unaffected. Manual stimulation led to faster glucose clearance and modified mainly gene expression in mesenteric adipose tissue (increased Nr4a3, Mapk3/Erk, Adcy3, Gsk3b), but not protein expression to the same extent; however, Nr4a3 was reduced in soleus muscle. The novel finding is that electrical and manual muscle stimulation affect glucose homeostasis in DHT-induced PCOS rats through different mechanisms. Repeated electrical stimulation regulated key functional molecular pathways important for insulin sensitivity in soleus muscle and mesenteric adipose tissue to a larger extent than manual stimulation. Manual stimulation improved whole-body glucose tolerance, an effect not observed after electrical stimulation, but did not affect molecular signaling pathways to the same extent as electrical stimulation. Although more functional signaling pathways related to insulin sensitivity were affected by electrical stimulation, our findings suggest that manual stimulation of acupuncture needles has a greater effect on glucose tolerance. The underlying mechanism of the differential effects of the intermittent manual and the continuous electrical stimulation remains to be elucidated.

Continuous administration of a P450 aromatase inhibitor induces polycystic ovary syndrome with a metabolic and endocrine phenotype in female rats at adult age.

Studying the mechanisms for the complex pathogenesis of polycystic ovary syndrome (PCOS) requires animal models with endocrine, reproductive, and metabolic features of the syndrome. Hyperandrogenism seems to be a central factor in PCOS, leading to anovulation and insulin resistance. In female rats, continuous administration of letrozole, a nonsteroidal inhibitor of P450 aromatase, at 400 µg/d starting before puberty induces hyperandrogenemia and reproductive abnormalities similar to those in women with PCOS. However, despite high circulating testosterone levels, these rats do not develop metabolic abnormalities, perhaps because of their supraphysiological testosterone concentrations or because estrogen synthesis is completely blocked in insulin-sensitive tissues. To test the hypothesis that continuous administration of lower doses of letrozole starting before puberty would result in both metabolic and reproductive phenotypes of PCOS, we performed a 12-wk dose-response study. At 21 d of age, 46 female Wistar rats were divided into two letrozole groups (100 or 200 µg/d) and a control group (placebo). Both letrozole doses resulted in increased body weight, inguinal fat accumulation, anovulation, larger ovaries with follicular atresia and multiples cysts, endogenous hyperandrogemia, and lower estrogen levels. Moreover, rats that received 200 µg/d had insulin resistance and enlarged adipocytes in inguinal and mesenteric fat depots, increased circulating levels of LH, decreased levels of FSH, and increased ovarian expression of Cyp17a1 mRNA. Thus, continuous administration of letrozole, 200 µg/d, to female rats for 90 d starting before puberty results in a PCOS model with reproductive and metabolic features of the syndrome.

Effects of acupuncture and exercise on insulin sensitivity, adipose tissue characteristics, and markers of coagulation and fibrinolysis in women with polycystic ovary syndrome: secondary analyses of a randomized controlled trial.

OBJECTIVE: To investigate the possible effects of low-frequency electroacupuncture (EA) and physical exercise on markers of coagulation and fibrinolysis, insulin sensitivity, and adipose tissue characteristics in women with polycystic ovary syndrome (PCOS). DESIGN: Secondary analyses of a prospective, randomized controlled clinical trial. SETTING: Department of Physiology and Department of Obstetrics and Gynecology, University of Gothenburg. PATIENT(S): Eighty-four women with PCOS were randomized. INTERVENTION(S): Women with PCOS were randomized to 16 weeks of low-frequency EA (14 treatments), physical exercise (at least 3 times/wk), or no intervention. MAIN OUTCOME MEASURE(S): Anthropometrics, circulating coagulation and fibrinolytic markers, insulin sensitivity (euglycemic hyperinsulinemic clamp), hemodynamics, and adipose tissue morphology/function recorded at baseline, after 16 weeks of intervention, and after a 16-week follow-up. RESULT(S): In the low-frequency EA group, circulating plasminogen activator inhibitor 1 activity decreased by 21.8% after 16 weeks of intervention and by 31.1% at the 16-week follow-up and differed from the physical exercise and the no intervention groups. The EA group had decreases in circulating fibrinogen and tissue plasminogen activator (t-PA), sagittal diameter, and diastolic blood pressure after treatment, and fibrinogen remained lower at the 16-week follow-up. In the physical exercise group, lipoprotein lipase activity increased and diastolic blood pressure decreased after treatment, and both diastolic and systolic blood pressure were lower at follow-up. No other variables were affected. CONCLUSION(S): Low-frequency EA counteracted a possible prothrombotic state in women with PCOS, as reflected by a decrease in plasminogen activator inhibitor 1 activity. Despite within-group improvements, there were no between-group differences in anthropometric, metabolic, or hemodynamic variables after 16 weeks of EA or physical exercise at the dose/intensity studied.

Dietary herring improves plasma lipid profiles and reduces atherosclerosis in obese low-density lipoprotein receptor-deficient mice.

Diet is a significant modifiable risk factor for cardiovascular disease and high fish intake has been associated with vascular health in population studies. However, intervention studies have been inconclusive. In this study, male low-density lipoprotein receptor-deficient mice were given 16-week high fat/high sucrose diets, supplemented with either minced herring fillets or minced beef. The diets were matched in total fat and cholesterol content; taurine content and fatty acid composition was analysed. Body weights were recorded throughout the study; plasma lipids were analysed at week 8 and 16. Body composition and adipocyte size were evaluated at study end. Atherosclerosis was evaluated at week 12 (ultrasound) and at termination (en face histology). Herring-fed mice had a higher proportion of long-chain n-3 polyunsaturated fatty acids in the hepatic triacylglycerides (TAG) and phospholipid fractions. The herring-fed mice had increased body weight (P=0.007), and reduced epididymal adipocyte size (P=0.009), despite similar food intake and body composition as the beef-fed mice. The herring-fed mice had lower plasma TAG and very-low-density lipoprotein (VLDL)-cholesterol concentrations throughout the study (TAG; P=0.0012 and 0.004, VLDL-cholesterol; P=0.006 and 0.041, week 8 and 16, respectively). At week 16, the herring-fed had higher plasma concentrations of HDL-cholesterol (P=0.004) and less atherosclerotic lesions in the aortic arch (P=0.007) compared with the beef-fed mice. In conclusion, dietary herring in comparison to beef markedly improved vascular health in this mouse model, suggesting that herring provides an added value beyond its content of macronutrients.

Coagulation and fibrinolytic disturbances in women with polycystic ovary syndrome.

CONTEXT: Studies of fibrinolysis/coagulation status in women with polycystic ovary syndrome (PCOS) are contradictory. OBJECTIVES: The aim of the study was to investigate whether women with PCOS have disturbed circulating levels of fibrinolysis/coagulation markers and, if so, whether the disturbances are related to hemodynamics, metabolic variables, sex steroids, SHBG, lipids, and inflammatory variables in women with PCOS. DESIGN/MAIN OUTCOME MEASURES: Anthropometric variables, hemodynamics, circulating hemostatic and inflammatory markers, and serum lipid profile were measured in women with untreated PCOS (n = 74) and controls (n = 31). RESULTS: After adjustments for age and body mass index (BMI), circulating plasminogen activator inhibitor 1 (PAI-1) activity and fibrinogen levels were higher in women with PCOS than controls; lipid profile, blood pressure, and levels of D-dimer, von Willebrand factor, factor VIII, tissue plasminogen activator, and inflammatory markers were comparable in the two groups. In multiple linear regression analyses including women with PCOS, low SHBG and high insulin predicted high PAI-1 activity (R(2) = 0.526; P < 0.001); elevated high-sensitivity C-reactive protein and soluble E-selectin in combination with heart rate predicted high fibrinogen (R(2) = 0.333; P < 0.001). Differences in PAI-1 activity were not significant after adjustments for age, BMI, SHBG, and insulin. CONCLUSIONS: PCOS is characterized by a prothrombotic state, as reflected by increased PAI-1 activity and fibrinogen, without signs of dyslipidemia or a proinflammatory state. Low SHBG and high insulin may partly explain the BMI-independent difference in PAI-1 activity between women with PCOS and controls. High-sensitivity C-reactive protein and E-selectin may be involved in regulating fibrinogen in PCOS.

Perinatal lack of maternal IL-6 promotes increased adiposity during adulthood in mice.

The perinatal environment appears important in establishing metabolic phenotypes in adulthood. Mice deficient in IL-6 (IL-6(-/-)) tend to develop mature-onset obesity, but it is unknown whether perinatal exposure to IL-6 produced by the dam influences the metabolism of adult offspring. To address this issue, we monitored IL-6(-/-) offspring of IL-6(-/-) or IL-6(+/-) dams, as well as wild-type (WT) mice. At adult age, IL-6(-/-) mice weighed significantly more and had more body fat than WT mice, regardless of maternal genotype, and had lower insulin sensitivity. This phenotype was more pronounced in IL-6(-/-) offspring of IL-6(-/-) dams, because they gained weight significantly faster than IL-6(-/-) offspring of IL-6(+/-) dams and had more body fat and higher serum leptin levels at an earlier age. The leptin content was 2-fold higher in milk from IL-6(-/-) than WT dams. However, cross-fostering IL-6(-/-) mice with WT dams did not alter body weight, body composition, or adipocyte size at adult age compared with IL-6(-/-) mice fostered by IL-6(-/-) dams. Conversely, WT mice fostered by IL-6(-/-) dams weighed significantly more than those fostered by WT dams and had more body fat, larger adipocytes, and altered hypothalamic gene expression. We conclude that body fat of adult mice can be increased by perinatal exposure to factors affected by lack of maternal IL-6.