Omental 11beta-hydroxysteroid dehydrogenase 1 correlates with fat cell size independently of obesity

The Role of microRNA in the Regulation of Cortisol Metabolism in the Adipose Tissue in the Course of Obesity

The similarity of the clinical picture of metabolic syndrome and hypercortisolemia supports the hypothesis that obesity may be associated with impaired expression of genes related to cortisol action and metabolism in adipose tissue. The expression of genes encoding the glucocorticoid receptor alpha (GR), cortisol metabolizing enzymes (HSD11B1, HSD11B2, H6PDH), and adipokines, as well as selected microRNAs, was measured by real-time PCR in adipose tissue from 75 patients with obesity, 19 patients following metabolic surgery, and 25 normal-weight subjects. Cortisol levels were analyzed by LC-MS/MS in 30 pairs of tissues. The mRNA levels of all genes studied were significantly (p < 0.05) decreased in the visceral adipose tissue (VAT) of patients with obesity and normalized by weight loss. In the subcutaneous adipose tissue (SAT), GR and HSD11B2 were affected by this phenomenon. Negative correlations were observed between the mRNA levels of the investigated genes and selected miRNAs (hsa-miR-142-3p, hsa-miR-561, and hsa-miR-579). However, the observed changes did not translate into differences in tissue cortisol concentrations, although levels of this hormone in the SAT of patients with obesity correlated negatively with mRNA levels for adiponectin. In conclusion, although the expression of genes related to cortisol action and metabolism in adipose tissue is altered in obesity and miRNAs may be involved in this process, these changes do not affect tissue cortisol concentrations.

Adipose tissue in cortisol excess: What Cushing's syndrome can teach us?

Endogenous Cushing's syndrome (CS) is a rare condition due to prolonged exposure to elevated circulating cortisol levels that features its typical phenotype characterised by moon face, proximal myopathy, easy bruising, hirsutism in females and a centripetal distribution of body fat. Given the direct and indirect effects of hypercortisolism, CS is a severe disease burdened by increased cardio-metabolic morbidity and mortality in which visceral adiposity plays a leading role. Although not commonly found in clinical setting, endogenous CS is definitely underestimated leading to delayed diagnosis with consequent increased rate of complications and reduced likelihood of their reversal after disease control. Most of all, CS is a unique model for systemic impairment induced by exogenous glucocorticoid therapy that is commonly prescribed for a number of chronic conditions in a relevant proportion of the worldwide population. In this review we aim to summarise on one side, the mechanisms behind visceral adiposity and lipid metabolism impairment in CS during active disease and after remission and on the other explore the potential role of cortisol in promoting adipose tissue accumulation.

Adipose organ dysfunction and type 2 diabetes: Role of nitric oxide

Adipose organ, historically known as specialized lipid-handling tissue serving as the long-term fat depot, is now appreciated as the largest endocrine organ composed of two main compartments, i.e., subcutaneous and visceral adipose tissue (AT), madding up white and beige/brown adipocytes. Adipose organ dysfunction manifested as maldistribution of the compartments, hypertrophic, hypoxic, inflamed, and insulin-resistant AT, contributes to the development of type 2 diabetes (T2D). Here, we highlight the role of nitric oxide (NO·) in AT (dys)function in relation to developing T2D. The key aspects determining lipid and glucose homeostasis in AT depend on the physiological levels of the NO· produced via endothelial NO· synthases (eNOS). In addition to decreased NO· bioavailability (via decreased expression/activity of eNOS or scavenging NO·), excessive NO· produced by inducible NOS (iNOS) in response to hypoxia and AT inflammation may be a critical interfering factor diverting NO· signaling to the formation of reactive oxygen and nitrogen species, resulting in AT and whole-body metabolic dysfunction. Pharmacological approaches boosting AT-NO· availability at physiological levels (by increasing NO· production and its stability), as well as suppression of iNOS-NO· synthesis, are potential candidates for developing NO·-based therapeutics in T2D.

Tissue Glucocorticoid Metabolism in Adrenal Insufficiency: A Prospective Study of Dual-release Hydrocortisone Therapy

BACKGROUND

Patients with adrenal insufficiency (AI) require life-long glucocorticoid (GC) replacement therapy. Within tissues, cortisol (F) availability is under the control of the isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD). We hypothesize that corticosteroid metabolism is altered in patients with AI because of the nonphysiological pattern of current immediate release hydrocortisone (IR-HC) replacement therapy. The use of a once-daily dual-release hydrocortisone (DR-HC) preparation, (Plenadren®), offers a more physiological cortisol profile and may alter corticosteroid metabolism in vivo.

STUDY DESIGN AND METHODS

Prospective crossover study assessing the impact of 12 weeks of DR-HC on systemic GC metabolism (urinary steroid metabolome profiling), cortisol activation in the liver (cortisone acetate challenge test), and subcutaneous adipose tissue (microdialysis, biopsy for gene expression analysis) in 51 patients with AI (primary and secondary) in comparison to IR-HC treatment and age- and BMI-matched controls.

RESULTS

Patients with AI receiving IR-HC had a higher median 24-hour urinary excretion of cortisol compared with healthy controls (72.1 µg/24 hours [IQR 43.6-124.2] vs 51.9 µg/24 hours [35.5-72.3], P = .02), with lower global activity of 11β-HSD2 and higher 5-alpha reductase activity. Following the switch from IR-HC to DR-HC therapy, there was a significant reduction in urinary cortisol and total GC metabolite excretion, which was most significant in the evening. There was an increase in 11β-HSD2 activity. Hepatic 11β-HSD1 activity was not significantly altered after switching to DR-HC, but there was a significant reduction in the expression and activity of 11β-HSD1 in subcutaneous adipose tissue.

CONCLUSION

Using comprehensive in vivo techniques, we have demonstrated abnormalities in corticosteroid metabolism in patients with primary and secondary AI receiving IR-HC. This dysregulation of pre-receptor glucocorticoid metabolism results in enhanced glucocorticoid activation in adipose tissue, which was ameliorated by treatment with DR-HC.

Interplay of Cortisol, Testosterone, and Abdominal Fat Mass in Normal-weight Women With Polycystic Ovary Syndrome

Context

Ovarian and adrenal steroidogenesis underlie endocrine-metabolic dysfunction in polycystic ovary syndrome (PCOS). Adipocytes express aldo-keto reductase 1C3 and type 1 11β-hydroxysteroid dehydrogenase, which modulate peripheral androgen and cortisol production.

Objectives

To compare serum adrenal steroids, including 11-oxygenated androgens (11-oxyandrogens), cortisol, and cortisone between normal-weight women with PCOS and body mass index- and age-matched ovulatory women with normal-androgenic profiles (controls), and assess whether adrenal steroids associate with abdominal adipose deposition.

Design

Prospective, cross-sectional, cohort study.

Setting

Academic medical center.

Patients

Twenty normal-weight women with PCOS and 20 body mass index-/age-matched controls.

Interventions

Blood sampling, IV glucose tolerance testing, and total-body dual-energy x-ray absorptiometry.

Main Outcome Measures

Clinical characteristics, hormonal concentrations, and body fat distribution.

Results

Women with PCOS had higher serum total/free testosterone (T) and androstenedione (A4) levels and a greater android/gynoid fat mass than controls (androgens P < .001; android/gynoid fat mass ratio, P = .026). Serum total/free T and A4 levels correlated positively with android/gynoid fat mass ratio in all women combined (P < .025, all values). Serum 11ß-hydroxyA4, 11-ketoA4, 11ß-hydroxyT, 11-ketoT, cortisol, and cortisone levels were comparable between female types and unrelated to body fat distribution. Serum 11-oxyandrogens correlated negatively with % total body fat, but lost significance adjusting for cortisol. Serum cortisol levels, however, correlated inversely with android fat mass (P = .021), with a trend toward reduced serum cortisol to cortisone ratio in women with PCOS vs controls (P = .075), suggesting diminished 11β-hydroxysteroid dehydrogenase activity.

Conclusion

Reduced cortisol may protect against preferential abdominal fat mass in normal-weight PCOS women with normal serum 11-oxyandrogens.

Broad Metabolome Alterations Associated with the Intake of Oral Contraceptives Are Mediated by Cortisol in Premenopausal Women

The use of oral contraceptives (OCs) has been associated with elevated blood cortisol concentrations. However, metabolic downstream effects of OC intake are not well described. Here, we aimed to determine if the blood metabolome is associated with the use of OCs and to estimate if these associations might be statistically mediated by serum cortisol concentrations. Plasma metabolites measured with the Biocrates AbsoluteIDQ p180 Kit and serum cortisol concentrations measured by an immunoassay were determined in 391 premenopausal women (116 OC users) participating in two independent cohorts of the Study of Health in Pomerania (SHIP). After correction for multiple testing, 27 metabolites were significantly associated with OC intake in SHIP-TREND (discovery cohort), of which 25 replicated in SHIP-2. Inter alia, associated metabolites included 12 out of 38 phosphatidylcholines with diacyl residue, 7 out of 14 lysophosphatidylcholines and 5 out of 21 amino acids. The associations with phosphatidylcholines were statistically mediated by cortisol, whereas lysophosphatidylcholines showed no mediation effect. The results represent a step toward a better understanding of the metabolic consequences of OC intake. Connecting cortisol with metabolic consequences of OC intake could help to understand the mechanisms underlying adverse effects. The blood metabolome may serve as a biomarker for identifying users at high risk for developing such adverse effects.

The association of cortisol curve features with incident diabetes among whites and African Americans: The CARDIA study

INTRODUCTION

A flatter diurnal cortisol curve has been associated with incident diabetes among older white adults. However, this relationship has not been examined among middle-aged individuals or African Americans [AA]. We analyzed the longitudinal association of baseline diurnal cortisol curve features with incident diabetes over a 10 year period in a cohort of AA and white participants who were, on average, 40 years old.

METHODS

Salivary cortisol was collected immediately post-awakening, then subsequently 45 min, 2.5 h, 8 h, and 12 h later, as well as at bedtime. Cortisol curve features included wake-up cortisol; cortisol awakening response (CAR); early, late, and overall decline slopes; bedtime cortisol; and 16 -h area under the curve (AUC). Salivary cortisol (nmol/L) was log-transformed due to positively skewed distributions. Diabetes was defined as fasting plasma glucose ≥ 126 mg/dL or taking diabetes medication. Logistic regression models were used to investigate the association of log-transformed cortisol curve features with incident diabetes. The analysis was stratified by race and adjusted for age, sex, education, depressive symptoms, smoking status, beta-blocker and steroid medication use and BMI.

RESULTS

Among 376 AA and 333 white participants (mean age 40 years), 67 incident diabetes cases occurred over 10 years. After full adjustment for additional covariates, a 1-unit log increase in CAR was associated with a 53 % lower odds of incident diabetes among whites (Odds Ratio [OR] 0.47, 95 % CI: 0.24, 0.90). A 1-SD increase in late decline slope was associated with a 416 % higher odds of incident diabetes among whites (OR 5.16, 95 % CI: 1.32, 20.20). There were no significant associations in AAs.

CONCLUSION

A robust CAR and flatter late decline slope are associated with lower and higher odds of incident diabetes, respectively, among younger to middle-aged whites and may provide a future target for diabetes prevention in this population.

PBMCs to Stress-Associated miR-18a-5p and miR-22-3p Ratios as New Indicators of Metabolic Syndrome

Purpose

Metabolic syndrome (MetS) is associated with chronic stress. miR-18a-5p and miR-22-3p are two miRNAs which can target the glucocorticoid receptor. This study looked at the changes in metabolic parameters and the predictive value of the peripheral blood mononuclear cells (PBMCs) to stress-associated miRNA ratios as new indicators in subjects with and without MetS in southern China. Patients and Methods. There were 81 participants (39 with MetS and 42 without MetS) in this cross-sectional study. The potential miRNAs were filtrated in the GEO database. The expression of miR-18a-5p and miR-22-3p in PBMCs was evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). The risk of miRNA and PBMCs to stress-associated miRNA ratios contributing to the presence of MetS was estimated by univariate and multivariate logistic regression models. The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic accuracy.

Results

MetS was positively correlated with cortisol, IL-6, lymphocyte to miR-18a-5p ratio (LT18R), lymphocyte to miR-22-3p ratio (LT22R), monocyte to miR-18a-5p ratio (MT18R), monocyte to miR-22-3p ratio (MT22R), PBMCs to miR-18a-5p ratio (PT18R), and PBMCs to miR-22-3p ratio (PT22R) and negatively associated with the expression levels of miR-18a-5p and miR-22-3p (P < 0.05). In addition, PT18R (odds ratio: 0.894; 95% CI: 0.823-0.966; P < 0.001) and PT22R (odds ratio: 0.809; 95% CI: 0.717-0.900; P < 0.001) were independent predictors of MetS, respectively. A receiver operating characteristic (ROC) curve analysis was performed to assess the value of the PT18R-PT22R (PMR) panel (odds ratio: 0.905; 95% CI: 0.838-0.971; P < 0.001) for predicting MetS. The area under the curve yielded a cut-off value of 0.608, with sensitivity of 74.4% and specificity of 95.2% (P < 0.001).

Conclusion

In summary, miR-18a-5p and miR-22-3p in PBMCs may be important biomarkers of stress reaction and may play a role in vulnerability to MetS. Besides, the inflammatory cells to the two miRNA ratios demonstrated high accuracy in the diagnosis of MetS.

Changes of BMI, steroid metabolome and psychopathology in patients with anorexia nervosa during hospitalization

Anorexia nervosa (AN) is associated with various alterations including the dysfunction of the HPA axis and consequently the hypercortisolemia and deficit in sex hormones but the comprehensive evaluation of changes in circulating steroids during the hospitalization of AN patients is lacking. We investigated the effect of realimentation of women with AN during hospitalization on 45 circulating steroids, the relationships between BMI, its change during hospitalization and physical activity, on one side and initial levels and their changes for two adipokines, circulating steroids, anorexia-specific (hunger, appetite and satiety), and anorexia non-specific symptoms (anxiety, depression fatigue, sleep, and body pain) on the other side. We included 33 women with anorexia who were hospitalized for 38(35, 44) days (median with quartiles). The increase of BMI from the initial value 15.2 (13.2, 16.6) kg/m² was 1.69 (1.37, 2.66) kg/m². The patients with more severe anorexia showed higher activity in 7β-, and 16α-hydroxylation of androgen precursors, which declined during hospitalization. Otherwise, the 7α-hydroxylation activity is higher in AN patients with less severe malnutrition and the ratio of 5-androstene-3β,7α,17β-triol to 5-androstene-3β,7β,17β-triol increased during the realimentation. Our data allow to speculate that the intensive 7β-, and 16α- and possibly also the 7α-hydroxylation of C19 Δ⁵ steroids participate in the pathophysiology of anorexia by additional catabolism of substrates available for synthesis of active androgens and estrogens. However, the question remains whether the synthetic analogues of 7α/β- and 16α-hydroxy-steroids prevent the catabolism of the sex steroid precursors, or further activate the "energy wasting" mitochondrial thermogenic metabolism.

Interaction of HSD11B1 and H6PD polymorphisms in subjects with type 2 diabetes are protective factors against obesity: a cross-sectional study

BACKGROUND

The enzyme 11-beta hydroxysteroid dehydrogenase type 1 (HSD11B1) converts inactive cortisone to active cortisol in a process mediated by the enzyme hexose-6-phosphate dehydrogenase (H6PD). The generation of cortisol from this reaction may increase intra-abdominal cortisol levels and contribute to the physiopathogenesis of obesity and metabolic syndrome (MetS). The relationship of HSD11B1 rs45487298 and H6PD rs6688832 polymorphisms with obesity and MetS was studied. We also studied how HSD11B1 abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) gene expression is related to body fat distribution.

METHODS

Rates of obesity and MetS features were cross-sectionally analyzed according to these polymorphisms in 1006 Brazilian white patients with type 2 diabetes (T2DM). Additionally, HSD11B1 expression was analyzed in VAT and SAT in a different cohort of 28 participants with and without obesity who underwent elective abdominal operations.

RESULTS

Although polymorphisms of the two genes were not individually associated with MetS features, a synergistic effect was observed between both. Carriers of at least three minor alleles exhibited lower BMI compared to those with two or fewer minor alleles adjusting for gender and age (27.4 ± 4.9 vs. 29.3 ± 5.3 kg/m²; P = 0.005; mean ± SD). Obesity frequency was also lower in the first group (24.4% vs. 41.6%, OR = 0.43, 95% CI 0.21-0.87; P = 0.019). In the second cohort of 28 subjects, HSD11B1 gene expression in VAT was inversely correlated with BMI (r = - 0.435, P = 0.034), waist circumference (r = - 0.584, P = 0.003) and waist-to-height ratio (r = - 0.526, P = 0.010).

CONCLUSIONS

These polymorphisms might interact in the protection against obesity in T2DM individuals. Obese individuals may have decreased intra-abdominal VAT HSD11B1 gene expression resulting in decreasing intra-abdominal cortisol levels as a compensatory mechanism against central and general adiposity.

Increased Ifi202b/IFI16 expression stimulates adipogenesis in mice and humans

AIMS/HYPOTHESIS

Obesity results from a constant and complex interplay between environmental stimuli and predisposing genes. Recently, we identified the IFN-activated gene Ifi202b as the most likely gene responsible for the obesity quantitative trait locus Nob3 (New Zealand Obese [NZO] obesity 3). The aim of this study was to evaluate the effects of Ifi202b on body weight and adipose tissue biology, and to clarify the functional role of its human orthologue IFI16.

METHODS

The impact of Ifi202b and its human orthologue IFI16 on adipogenesis was investigated by modulating their respective expression in murine 3T3-L1 and human Simpson-Golabi-Behmel syndrome (SGBS) pre-adipocytes. Furthermore, transgenic mice overexpressing IFI202b were generated and characterised with respect to metabolic traits. In humans, expression levels of IFI16 in adipose tissue were correlated with several variables of adipocyte function.

RESULTS

In mice, IFI202b overexpression caused obesity (Δ body weight at the age of 30 weeks: 10.2 ± 1.9 g vs wild-type mice) marked by hypertrophic fat mass expansion, increased expression of Zfp423 (encoding the transcription factor zinc finger protein [ZFP] 423) and white-selective genes (Tcf21, Tle3), and decreased expression of thermogenic genes (e.g. Cidea, Ucp1). Compared with their wild-type littermates, Ifi202b transgenic mice displayed lower body temperature, hepatosteatosis and systemic insulin resistance. Suppression of IFI202b/IFI16 in pre-adipocytes impaired adipocyte differentiation and triacylglycerol storage. Humans with high levels of IFI16 exhibited larger adipocytes, an enhanced inflammatory state and impaired insulin-stimulated glucose uptake in white adipose tissue.

CONCLUSIONS/INTERPRETATION

Our findings reveal novel functions of Ifi202b and IFI16, demonstrating their role as obesity genes. These genes promote white adipogenesis and fat storage, thereby facilitating the development of obesity-associated insulin resistance.

Feeding Obese Diabetic Mice a Genistein Diet Induces Thermogenic and Metabolic Change

Obesity is associated with elevated plasma levels of glucocorticoids and reduced levels of thyroid hormones, both known to effect food intake and energy expenditure. Furthermore, tissue specific glucocorticoid metabolism is altered in obesity, increasing insulin resistance and cardiometabolic risk. The goal of this study was to examine whether these metabolic disturbances can be prevented with the isoflavone genistein in the ob/ob mouse, a model that resembles the phenotype in human obesity. Male ob/ob mice, aged 5 weeks, were fed either a genistein-rich diet (600 mg/kg) or a genistein-free diet for 4 weeks. ob/ob mice weighed 70% more than lean controls. While there was no effect of genistein on body weight, food consumption during weeks 3 and 4 was significantly increased in genistein-fed mice. This was associated with increases in body temperature and plasma levels of triiodothyronine (T3), suggesting a thermogenic effect. The hypercorticosteronism observed in the ob/ob mouse was reduced with genistein treatment. This effect was accompanied by a decrease in protein expression of renal 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) without changes in hepatic 11β-HSD1. Our results suggest that a diet containing genistein can have beneficial effects on energy expenditure, T3 production, and corticosterone status in the ob/ob mouse model of obesity.

Fructose-induced inflammation and increased cortisol: A new mechanism for how sugar induces visceral adiposity

Traditionally, the leading hypothesis regarding the development of obesity involves caloric imbalance, whereby the amount of calories consumed exceeds the amount of calories burned which causes obesity. Another hypothesis for why we get fat has surfaced in the last decade which is the idea that the overconsumption of added sugars and refined carbohydrates induce insulin resistance and high insulin levels causing obesity. While insulin is a fat-storing hormone, this hypothesis does not explain visceral adiposity, or why certain people are found to have fat stored in and around their organs. We propose a new mechanism for body fattening, particular visceral adiposity. This hypothesis involves the overconsumption of fructose, which leads to inflammation in all cells that metabolize it rapidly. When fructose is metabolized in subcutaneous adipocytes, the subsequent inflammation leads to an increase in intracellular cortisol in order to help squelch the inflammation. Unfortunately, the increase in intracellular cortisol leads to an increased flux of fatty acids out of the subcutaneous adipocytes allowing more substrate for fat storage into visceral fat tissue. Moreover fructose-induced inflammation in the liver also leads to increased intracellular cortisol via an upregulation of 11-B hydroxysteroid dehydrogenase type 1 causing increased fat storage in the liver (i.e., fatty liver). In essence, the fructose-induced inflammatory cortisol response causes "thin on the outside, fat on the inside" (TOFI). Furthermore, fructose in the brain, either from fructose uptake via the blood brain barrier or endogenous formation from glucose via the polyol pathway stimulates an increased release of cortisol causing hepatic gluconeogenesis leading to overall insulin resistance and further body fattening. This review paper will discuss in detail the hypothesis that fructose-induced inflammation and cortisol activation causes visceral adiposity.

Influence of sub-chronic selective 11β-hydroxysteroid dehydrogenase 1 inhibition on the hypothalamic-pituitary-adrenal axis in female cynomolgus monkeys

Inhibition of local cortisol regeneration from circulating cortisone by blocking 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) has been shown to ameliorate the risk factors associated with the metabolic syndrome. Chronic modulation of glucocorticoid homeostasis may result in hypothalamic-pituitary-adrenal (HPA) axis stimulation. HPA axis over-activation leading androgen excess would be undesirable in a therapeutic intervention designed to treat a chronic condition such as the metabolic syndrome. To address whether 11β-HSD1 inhibition would lead to excess androgens, we treated female cynomolgus monkeys with a selective inhibitor, BI 135558, for 4 weeks. Continual action of the compound over the dosing period was confirmed by constant plasma exposure, and a maintained change in urinary glucocorticoid metabolites consistent with 11β-HSD1 inhibition. No significant changes in adrenal function, as evidenced by an adrenocorticotropic hormone (ATCH) challenge, were observed. An examination of androgenic hormones revealed a slight increase in dehydroepiandrosterone sulfate (DHEA-S), while other hormones such as testosterone remained within reference values. Overall, treatment with BI 135558 in monkeys did not result in obvious over-activation of the HPA axis.

Accumulation of CD11c+CD163+ Adipose Tissue Macrophages through Upregulation of Intracellular 11β-HSD1 in Human Obesity

Adipose tissue (AT) macrophages (ATMs) are key players for regulation of AT homeostasis and obesity-related metabolic disorders. However, the phenotypes of human ATMs and regulatory mechanisms of their polarization have not been clearly described. In this study, we investigated human ATMs in both abdominal visceral AT and s.c. AT and proposed an 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1)-glucocorticoid receptor regulatory axis that might dictate M1/M2 polarization in ATMs. The accumulation of CD11c⁺CD163⁺ ATMs in both visceral AT and s.c. AT of obese individuals was confirmed at the cellular level and was found to be clearly correlated with body mass index and production of reactive oxygen species. Using our in vitro system where human peripheral blood monocytes (hPBMs) were cocultured with Simpson-Golabi-Behmel syndrome adipocytes, M1/M2 polarization was found to be dependent on 11β-HSD1, an intracellular glucocorticoid reactivating enzyme. Exposure of hPBMs to cortisol-induced expression of CD163 and RU-486, a glucocorticoid receptor antagonist, significantly abrogated CD163 expression through coculture of mature adipocytes with hPBMs. Moreover, 11β-HSD1 was expressed in crown ATMs in obese AT. Importantly, conditioned medium from coculture of adipocytes with hPBMs enhanced proliferation of human breast cancer MCF7 and MDA-MB-231 cells. In summary, the phenotypic switch of ATMs from M2 to mixed M1/M2 phenotype occurred through differentiation of adipocytes in obese individuals, and upregulation of intracellular 11β-HSD1 might play a role in the process.

Updated survey of the steroid-converting enzymes in human adipose tissues

Over the past decade, adipose tissues have been increasingly known for their endocrine properties, that is, their ability to secrete a number of adipocytokines that may exert local and/or systemic effects. In addition, adipose tissues have long been recognized as significant sites for steroid hormone transformation and action. We hereby provide an updated survey of the many steroid-converting enzymes that may be detected in human adipose tissues, their activities and potential roles. In addition to the now well-established role of aromatase and 11β-hydroxysteroid dehydrogenase (HSD) type 1, many enzymes have been reported in adipocyte cell lines, isolated mature cells and/or preadipocytes. These include 11β-HSD type 2, 17β-HSDs, 3β-HSD, 5α-reductases, sulfatases and glucuronosyltransferases. Some of these enzymes are postulated to bear relevance for adipose tissue physiology and perhaps for the pathophysiology of obesity. This elaborate set of steroid-converting enzymes in the cell types of adipose tissue deserves further scientific attention. Our work on 20α-HSD (AKR1C1), 3α-HSD type 3 (AKR1C2) and 17β-HSD type 5 (AKR1C3) allowed us to clarify the relevance of these enzymes for some aspects of adipose tissue function. For example, down-regulation of AKR1C2 expression in preadipocytes seems to potentiate the inhibitory action of dihydrotestosterone on adipogenesis in this model. Many additional studies are warranted to assess the impact of intra-adipose steroid hormone conversions on adipose tissue functions and chronic conditions such as obesity, diabetes and cancer.

Association of HSD11B1 polymorphic variants and adipose tissue gene expression with metabolic syndrome, obesity and type 2 diabetes mellitus: a systematic review

The HSD11B1 gene is highly expressed in abdominal adipose tissue, and the enzyme it encodes catalyzes the interconversion of inactive cortisone to hormonally active cortisol. Genetic abnormalities of HSD11B1 have been associated with the development of abnormal glucose metabolism and body fat distribution. To systematically review studies evaluating the association of HSD11B1 gene expression in abdominal adipose tissue and HSD11B1 polymorphisms with obesity, the metabolic syndrome (MetS), and type 2 diabetes (T2DM), we conducted a search in MEDLINE, SCOPUS, and Cochrane Library databases in April 2015. The inclusion criteria were observational studies (cross-sectional, cohort, or case-control), conducted in adults, which analyzed the relationship of HSD11B1 polymorphisms and/or HSD11B1 expression in abdominal adipose tissue with obesity, MetS, or T2DM. Of 802 studies retrieved, 32 met the inclusion criteria (23 gene expression and 9 polymorphism studies). Twenty one studies analyzed the relationship between abdominal subcutaneous and/or visceral HSD11B1 expression with central and/or generalized obesity. Most studies reported that abdominal adipose HSD11B1 expression increased with increasing body mass index (15 studies) and abnormalities of glucose metabolism (7 studies), and varied with the presence of MetS (3 studies). Nine studies analyzed the association of 26 different HSD11B1 polymorphic variants with obesity, MetS, and T2DM. Only an Indian study found an association between a polymorphic variant at the HSD11B1 gene with MetS whereas in Pima Indians another polymorphic variant was found to be associated with T2DM. While the literature suggests that HSD11B1 is hyperexpressed in abdominal adipose tissue in subjects with obesity and abnormal glucose metabolism, this seems to be not true for HSD11B1 gene expression and MetS. Although an association of polymorphic variants of HSD11B1 with MetS in Indians and in the T2DM population of Pima Indians were found, most studies did not find a relationship between genetic polymorphic variants of HSD11B1 and obesity, MetS, and T2DM. Their reported conflicting and inconclusive results, suggesting that polymorphic variants of HSD11B1 may have only a small role in the development of metabolic abnormalities of susceptible populations in the development of MetS and T2DM.

Enzymatic intracrine regulation of white adipose tissue

Abdominal fat formation has become a permanent risk factor for metabolic syndrome and various cancers in one-third of the world's population of obese and even lean patients. Formation of abdominal fat involves additional mechanisms beyond an imbalance in energy intake and expenditure, which explains systemic obesity. In this review, we briefly summarized autonomous regulatory circuits that locally produce hormones from inactive precursors or nutrients for intra-/auto-/paracrine signaling in white adipose depots. Enzymatic pathways activating steroid and thyroid hormones in adipose depots were compared with enzymatic production of retinoic acid from vitamin A. We discussed the role of intracrine circuits in fat-depot functions and strategies to reduce abdominal adiposity through thermogenic adipocytes with interrupted generation of retinoic acid.

Tissue-specific dysregulation of cortisol regeneration by 11βHSD1 in obesity: has it promised too much?

Cushing's syndrome, caused by increased production of cortisol, leads to metabolic dysfunction including visceral adiposity, hypertension, hyperlipidaemia and type 2 diabetes. The similarities with the metabolic syndrome are striking and major efforts have been made to find obesity-associated changes in the regulation of glucocorticoid action and synthesis, both at a systemic level and tissue level. Obesity is associated with tissue-specific alterations in glucocorticoid metabolism, with increased activity of the glucocorticoid-regenerating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) in subcutaneous adipose tissue and decreased conversion of cortisone to cortisol, interpreted as decreased 11βHSD1 activity, in the liver. In addition, genetic manipulation of 11βHSD1 activity in rodents can either induce (by overexpression of Hsd11b1, the gene encoding 11βHSD1) or prevent (by knocking out Hsd11b1) obesity and metabolic dysfunction. Taken together with earlier evidence that non-selective inhibitors of 11βHSD1 enhance insulin sensitivity, these results led to the hypothesis that inhibition of 11βHSD1 might be a promising target for treatment of the metabolic syndrome. Several selective 11βHSD1 inhibitors have now been developed and shown to improve metabolic dysfunction in patients with type 2 diabetes, but the small magnitude of the glucose-lowering effect has precluded their further commercial development.This review focuses on the role of 11βHSD1 as a tissue-specific regulator of cortisol exposure in obesity and type 2 diabetes in humans. We consider the potential of inhibition of 11βHSD1 as a therapeutic strategy that might address multiple complications in patients with type 2 diabetes, and provide our thoughts on future directions in this field.

Wnt/β-catenin signaling pathway and lipolysis enzymes participate in methylprednisolone induced fat differential distribution between subcutaneous and visceral adipose tissue

Glucocorticoids (GCs) are well known to induce fat distribution, which is consistent with the central adiposity phenotype seen in Cushing's syndrome. GCs have been proposed to be both adipogenic and lipolytic in action within adipose tissues. Different adipogenic and lipolytic effects between subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) are likely to play a role in GCs induced fat differential distribution. Wnt/β-catenin signaling pathway is one of the most important regulators in adipogenesis. Adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL) are the major lipases contributing to lipolysis. In the present study, we measured fat depot masses and the expression of Wnt/β-catenin signaling pathway and lipolytic enzymes of female Sprague-Dawley rats treated with or without methylprednisolone. We assessed the roles of Wnt/β-catenin signaling pathway and lipolytic enzymes in fat differential distribution between SAT and VAT. Our data suggested that methylprednisolone could inhibit Wnt/β-catenin signaling pathway in SAT and VAT, increase the expression of ATGL and HSL in SAT, and decrease the expression of ATGL and HSL in VAT. The differential expression of lipolysis enzymes induced by methylprednisolone between SAT and VAT might play a crucial role in fat distribution. Those findings would offer novel insights into the mechanisms of GCs induced fat distribution.

Glucocorticoid receptor gene expression in adipose tissue and associated metabolic risk in black and white South African women

BACKGROUND

Black women have lower visceral adipose tissue (VAT) but are less insulin sensitive than white women; the mechanisms responsible are unknown.

OBJECTIVE

The study aimed to test the hypothesis that variation in subcutaneous adipose tissue (SAT) sensitivity to glucocorticoids might underlie these differences.

METHODS

Body fatness (dual energy X-ray absorptiometry) and distribution (computerized tomography), insulin sensitivity (SI, intravenous and oral glucose tolerance tests), and expression of 11β-hydroxysteroid dehydrogenase-1 (11HSD1), hexose-6-phosphate dehydrogenase and glucocorticoid receptor-α (GRα), as well as genes involved in adipogenesis and inflammation were measured in abdominal deep SAT, superficial SAT and gluteal SAT (GLUT) depots of 56 normal-weight or obese black and white premenopausal South African (SA) women. We used a combination of univariate and multivariate statistics to evaluate ethnic-specific patterns in adipose gene expression and related body composition and insulin sensitivity measures.

RESULTS

Although 11HSD1 activity and mRNA did not differ by ethnicity, GRα mRNA levels were significantly lower in SAT of black compared with white women, particularly in the GLUT depot (0.52±0.21 vs 0.91±0.26 AU, respectively, P<0.01). In black women, lower SAT GRα mRNA levels were associated with increased inflammatory gene transcript levels and abdominal SAT area, and reduced adipogenic gene transcript levels, VAT/SAT ratio and SI. Abdominal SAT 11HSD1 activity associated with increased VAT area and decreased SI in white, but not in black women.

CONCLUSIONS

In black SA women, downregulation of GRα mRNA levels with obesity and reduced insulin sensitivity, possibly via increased SAT inflammation, is associated with reduced VAT accumulation.

Obesity and surgical wound healing: a current review

Objective. The correlation between obesity and deficient wound healing has long been established. This review examines the current literature on the mechanisms involved in obesity-related perioperative morbidity. Methods. A literature search was performed using Medline, PubMed, Cochrane Library, and Internet searches. Keywords used include obesity, wound healing, adipose healing, and bariatric and surgical complications. Results. Substantial evidence exists demonstrating that obesity is associated with a number of postoperative complications. Specifically in relation to wound healing, explanations include inherent anatomic features of adipose tissue, vascular insufficiencies, cellular and composition modifications, oxidative stress, alterations in immune mediators, and nutritional deficiencies. Most recently, advances made in the field of gene array have allowed researchers to determine a few plausible alterations and deficiencies in obese individuals that contribute to their increased risk of morbidity and mortality, especially wound complications. Conclusion. While the literature discusses how obesity may negatively affect health on various of medical fronts, there is yet to be a comprehensive study detailing all the mechanisms involved in obesity-related morbidities in their entirety. Improved knowledge and understanding of obesity-induced physiological, cellular, molecular, and chemical changes will facilitate better assessments of surgical risks and outcomes and create efficient treatment protocols for improved patient care of the obese patient population.

Dietary fructose-related adiposity and glucocorticoid receptor function in visceral adipose tissue of female rats

PURPOSE

Excessive fructose intake coincides with the growing rate of obesity and metabolic syndrome, with women being more prone to these disorders than men. Findings that detrimental effects of fructose might be mediated by glucocorticoid regeneration in adipose tissue only indirectly implicated glucocorticoid receptor (GR) in the phenomenon. The aim of the present study was to elucidate whether fructose overconsumption induces derangements in GR expression and function that might be associated with fructose-induced adiposity in females.

METHODS

We examined effects of fructose-enriched diet on GR expression and function in visceral adipose tissue of female rats. Additionally, we analyzed the expression of genes involved in glucocorticoid prereceptor metabolism [11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) and hexose-6-phosphate dehydrogenase], lipolysis (hormone-sensitive lipase) and lipogenesis (sterol regulatory element binding protein 1 and peroxisomal proliferator-activated receptor γ).

RESULTS

Fructose-fed rats had elevated energy intake that resulted in visceral adiposity, as indicated by increased visceral adipose tissue mass and its share in the whole-body weight. GR hormone binding capacity and affinity, as well as the expression of GR gene at both mRNA and protein levels were reduced in visceral adipose tissue of the rats on fructose diet. The glucocorticoid prereceptor metabolism was stimulated, as evidenced by elevated tissue corticosterone, while the key regulators of lipolysis and lipogenesis remained unaffected by fructose diet.

CONCLUSIONS

The results suggest that the 11βHSD1-mediated elevation of intracellular corticosterone may induce GR downregulation, which may be associated with failure of GR to stimulate lipolysis in fructose-fed female rats.

11β-hydroxysteroid dehydrogenases: intracellular gate-keepers of tissue glucocorticoid action

Glucocorticoid action on target tissues is determined by the density of "nuclear" receptors and intracellular metabolism by the two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD) which catalyze interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone. 11β-HSD type 1, a predominant reductase in most intact cells, catalyzes the regeneration of active glucocorticoids, thus amplifying cellular action. 11β-HSD1 is widely expressed in liver, adipose tissue, muscle, pancreatic islets, adult brain, inflammatory cells, and gonads. 11β-HSD1 is selectively elevated in adipose tissue in obesity where it contributes to metabolic complications. Similarly, 11β-HSD1 is elevated in the ageing brain where it exacerbates glucocorticoid-associated cognitive decline. Deficiency or selective inhibition of 11β-HSD1 improves multiple metabolic syndrome parameters in rodent models and human clinical trials and similarly improves cognitive function with ageing. The efficacy of inhibitors in human therapy remains unclear. 11β-HSD2 is a high-affinity dehydrogenase that inactivates glucocorticoids. In the distal nephron, 11β-HSD2 ensures that only aldosterone is an agonist at mineralocorticoid receptors (MR). 11β-HSD2 inhibition or genetic deficiency causes apparent mineralocorticoid excess and hypertension due to inappropriate glucocorticoid activation of renal MR. The placenta and fetus also highly express 11β-HSD2 which, by inactivating glucocorticoids, prevents premature maturation of fetal tissues and consequent developmental "programming." The role of 11β-HSD2 as a marker of programming is being explored. The 11β-HSDs thus illuminate the emerging biology of intracrine control, afford important insights into human pathogenesis, and offer new tissue-restricted therapeutic avenues.

Changing glucocorticoid action: 11β-hydroxysteroid dehydrogenase type 1 in acute and chronic inflammation

Since the discovery of cortisone in the 1940s and its early success in treatment of rheumatoid arthritis, glucocorticoids have remained the mainstay of anti-inflammatory therapies. However, cortisone itself is intrinsically inert. To be effective, it requires conversion to cortisol, the active glucocorticoid, by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Despite the identification of 11β-HSD in liver in 1953 (which we now know to be 11β-HSD1), its physiological role has been little explored until recently. Over the past decade, however, it has become apparent that 11β-HSD1 plays an important role in shaping endogenous glucocorticoid action. Acute inflammation is more severe with 11β-HSD1-deficiency or inhibition, yet in some inflammatory settings such as obesity or diabetes, 11β-HSD1-deficiency/inhibition is beneficial, reducing inflammation. Current evidence suggests both beneficial and detrimental effects may result from 11β-HSD1 inhibition in chronic inflammatory disease. Here we review recent evidence pertaining to the role of 11β-HSD1 in inflammation. This article is part of a Special Issue entitled 'CSR 2013'.

11β-Hydroxysteroid dehydrogenase 1: translational and therapeutic aspects

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts the inactive glucocorticoid cortisone and its active form cortisol. It is widely expressed and, although bidirectional, in vivo it functions predominantly as an oxoreductase, generating active glucocorticoid. This allows glucocorticoid receptor activation to be regulated at a prereceptor level in a tissue-specific manner. In this review, we will discuss the enzymology and molecular biology of 11β-HSD1 and the molecular basis of cortisone reductase deficiencies. We will also address how altered 11β-HSD1 activity has been implicated in a number of disease states, and we will explore its role in the physiology and pathologies of different tissues. Finally, we will address the current status of selective 11β-HSD1 inhibitors that are in development and being tested in phase II trials for patients with the metabolic syndrome. Although the data are preliminary, therapeutic inhibition of 11β-HSD1 is also an exciting prospect for the treatment of a variety of other disorders such as osteoporosis, glaucoma, intracranial hypertension, and cognitive decline.

Cortisol metabolism after weight loss: associations with 11 β-HSD type 1 and markers of obesity in women

OBJECTIVE

Increased glucocorticoid metabolite excretion and enhanced expression and activity of 11β-hydroxysteroid dehydrogenase type 1 in adipose tissue are closely correlated with obesity and its detrimental consequences. Weight loss ameliorates the latter. The aim of this study was to explore whether increased glucocorticoid exposure in obesity is improved with substantial weight loss and thus is a consequence rather than a cause of obesity.

DESIGN AND PATIENTS

A prospective cohort study in 31 women.

MEASUREMENTS

11β-HSD type 1 expression and activity, urinary glucocorticoid metabolite excretion, body composition including regional adipose tissue depots and insulin resistance by HOMA-IR before and 2 years after gastric bypass surgery.

RESULTS

After weight loss, excretion of cortisol and cortisone metabolites decreased. Both cortisol and cortisone metabolite excretion correlated with central obesity, where the intraabdominal fat depot showed the strongest association. Cortisol metabolites correlated with 11β-HSD type 1 activity in abdominal subcutaneous adipose tissue. The ratio of cortisol to cortisone metabolites [(5α-tetrahydrocortisol (5αTHF) + tetrahydrocortisol (THF) + α-cortol)/(tetrahydrocortisone (THE) + α-cortolone)] and the ratio of 5α-THF/THF both decreased after stable weight loss, reflecting a downregulation of the net activities of 11β-HSD type 1 and 5α-reductase.

CONCLUSION

Long-term weight loss in women is not only followed by reduced glucocorticoid production, but also favourably decreases the global and tissue-specific activity of the cortisol-activating enzyme 11 β-HSD type 1, possibly contributing to the health benefits of bariatric surgery.

Pathophysiology of human visceral obesity: an update

Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.

11beta-Hydroxysteroid dehydrogenase type 1 inhibitors: novel agents for the treatment of metabolic syndrome and obesity-related disorders?

OBJECTIVE

Metabolic syndrome (MetS) and Cushing's syndrome share common features. It has been proposed that increased glucocorticoid activity at peripheral tissues may play a role in the pathogenesis of MetS and obesity-related disorders. It is well-known that intracellular cortisol concentrations are determined not only by plasma levels but also by the activity of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) which catalyzes the conversion of inactive cortisone to active cortisol, especially in the liver and adipose tissue. Another isoenzyme exists, the 11β-hydroxysteroid dehydrogenase type 2, which acts in the opposite direction inactivating cortisol to cortisone in the kidney. This review considers the significance of the 11β-HSD1 inhibition in the treatment of several features of MetS and provides current data about the development of 11β-HSD1 inhibitors, as new agents for this purpose.

MATERIALS/METHODS

Using PubMed, we searched for publications during the last 20years regarding the development of 11β-HSD1 inhibitors.

RESULTS

Emerging data from animal and human studies indicate an association of 11β-HSD1 over-expression with obesity and disorders in glucose and lipid metabolism. This has led to the hypothesis that selective inhibition of 11β-HSD1 could be used to treat MetS and diabetes. Indeed, natural products and older agents such as thiazolidinediones and fibrates seem to exert an inhibitory effect on 11β-HSD1, ameliorating the cardiometabolic profile. In view of this concept, novel compounds, such as adamantyltriazoles, arylsulfonamidothiazoles, anilinothiazolones, BVT2733, INCB-13739, MK-0916 and MK-0736, are currently under investigation and the preliminary findings from both experimental and human studies show a favourable effect on glucose and lipid metabolism, weight reduction and adipokine levels.

CONCLUSIONS

Many compounds inhibiting 11β-ΗSD1 are under development and preliminary data about their impact on glucose metabolism and obesity-related disorders are encouraging.

Loss of function of Ifi202b by a microdeletion on chromosome 1 of C57BL/6J mice suppresses 11β-hydroxysteroid dehydrogenase type 1 expression and development of obesity

Nob3 is a major obesity quantitative trait locus (QTL) identified in an intercross of New Zealand Obese (NZO) mice with C57BL/6J (B6), and by introgression of its 38 Mbp peak region into B6 (B6.NZO-Nob3.38). B6.NZO-Nob3.38 mice carrying the NZO allele exhibited markedly increased body weight, fat mass, lean mass and a lower energy expenditure, than the corresponding B6 allele carriers. For positional cloning of the responsible obesity gene, five additional congenic lines (RCS) were generated and characterized, allowing to define a critical genomic interval comprising 43 genes. mRNA profiling and western blotting indicated that Ifi202b, a member of the Ifi200 family of interferon inducible transcriptional modulators, was expressed in NZO-allele carriers but was undetectable in tissues of homozygous B6-allele carriers due to a microdeletion, including the first exon and the 5'-flanking region of Ifi202b in B6. Transcriptome analysis of adipose tissue of RCS revealed a marked induction of 11β-hydroxysteroid dehydrogenase type 1 (11β-Hsd1) expression in mice expressing Ifi202b. Furthermore, siRNA-mediated Ifi202b suppression in 3T3-L1 adipocytes resulted in a significant inhibition of 11β-Hsd1 expression, whereas an adenoviral-mediated overexpression of Ifi202b increased 11β-Hsd1 mRNA levels. Expression of human IFI orthologues was significantly increased in visceral adipose tissue of obese subjects. We suggest that the disruption of Ifi202b in B6 is responsible for the effects of the obesity QTL Nob3, and that Ifi202b modulates fat accumulation through expression of adipogenic genes such as 11β-Hsd1.

Glucocorticoid-induced androgen inactivation by aldo-keto reductase 1C2 promotes adipogenesis in human preadipocytes

Adipogenesis and lipid storage in human adipose tissue are inhibited by androgens such as DHT. Inactivation of DHT to 3α-diol is stimulated by glucocorticoids in human preadipocytes. We sought to characterize glucocorticoid-induced androgen inactivation in human preadipocytes and to establish its role in the antiadipogenic action of DHT. Subcutaneous and omental primary preadipocyte cultures were established from fat samples obtained in subjects undergoing abdominal surgeries. Inactivation of DHT to 3α/β-diol for 24 h was measured in dexamethasone- or vehicle-treated cells. Specific downregulation of aldo-keto reductase 1C (AKR1C) enzymes in human preadipocytes was achieved using RNA interference. In whole adipose tissue sample, cortisol production was positively correlated with androgen inactivation in both subcutaneous and omental adipose tissue (P < 0.05). Maximal dexamethasone (1 μM) stimulation of DHT inactivation was higher in omental compared with subcutaneous fat from men as well as subcutaneous and omental fat from women (P < 0.05). A significant positive correlation was observed between BMI and maximal dexamethasone-induced DHT inactivation rates in subcutaneous and omental adipose tissue of men and women (r = 0.24, n = 26, P < 0.01). siRNA-induced downregulation of AKR1C2, but not AKR1C1 or AKR1C3, significantly reduced basal and glucocorticoid-induced androgen inactivation rates (P < 0.05). The inhibitory action of DHT on preadipocyte differentiation was potentiated following AKR1C2 but not AKR1C1 or AKR1C3 downregulation. Specifically, lipid accumulation, G3PDH activity, and FABP4 mRNA expression in differentiated preadipocytes exposed to DHT were reduced further upon AKR1C2 siRNA transfection. We conclude that glucocorticoid-induced androgen inactivation is mediated by AKR1C2 and is particularly effective in omental preadipocytes of obese men. The interplay between glucocorticoids and AKR1C2-dependent androgen inactivation may locally modulate adipogenesis and lipid accumulation in a depot-specific manner.

The expression of omental 11β-HSD1 is not increased in severely obese women with metabolic syndrome

OBJECTIVE

Plasma cortisol in obese subjects does not differ from that in normoweight subjects. Extra-adrenal cortisol production by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) can result in local hypercortisolemia. The aim of the present study was to examine the role of visceral hypercortisolemia in the development of metabolic syndrome in severe obesity.

METHODS

Eight lean women during hysterectomy (controls) and 19 severely obese women during bariatric surgery were studied, 8 without metabolic syndrome (OM- group) and 11 with it (OM+ group). Biopsies of omental and subcutaneous fat were performed in the severely obese women during surgery, but only omental biopsies in the controls. Expression of 11β-HSD1, glucocorticoid receptor α (GRα) and glucocorticoid receptor β (GRβ) was evaluated using real-time PCR.

RESULTS

Omental 11β-HSD1 expression was different between groups (one-way ANOVA, p < 0.01). Post-hoc analysis revealed that mean omental 11β-HSD1 mRNA levels were higher in the OM- group compared to controls, whereas they were similar when comparing the OM+ group with lean controls. Expression of 11β-HSD1 in subcutaneous fat was not different between OM+ and OM- groups. GRα expression in omental fat did not differ among groups or between omental and subcutaneous fat in severely obese patients. An expression of GRβ was not detected.

CONCLUSION

Contrary to our original hypothesis, omental 11β-HSD1 expression is not increased in the OM+ group.

Increased angiogenesis protects against adipose hypoxia and fibrosis in metabolic disease-resistant 11β-hydroxysteroid dehydrogenase type 1 (HSD1)-deficient mice

In obesity, rapidly expanding adipose tissue becomes hypoxic, precipitating inflammation, fibrosis, and insulin resistance. Compensatory angiogenesis may prevent these events. Mice lacking the intracellular glucocorticoid-amplifying enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1^−/−) have “healthier” adipose tissue distribution and resist metabolic disease with diet-induced obesity. Here we show that adipose tissues of 11βHSD1^−/− mice exhibit attenuated hypoxia, induction of hypoxia-inducible factor (HIF-1α) activation of the TGF-β/Smad3/α-smooth muscle actin (α-SMA) signaling pathway, and fibrogenesis despite similar fat accretion with diet-induced obesity. Moreover, augmented 11βHSD1^−/− adipose tissue angiogenesis is associated with enhanced peroxisome proliferator-activated receptor γ (PPARγ)-inducible expression of the potent angiogenic factors VEGF-A, apelin, and angiopoietin-like protein 4. Improved adipose angiogenesis and reduced fibrosis provide a novel mechanism whereby suppression of intracellular glucocorticoid regeneration promotes safer fat expansion with weight gain.

Local metabolism of glucocorticoids in Prague hereditary hypertriglyceridemic rats--effect of hypertriglyceridemia and gender

11β-Hydroxysteroid dehydrogenase type 1 (11HSD1) is a microsomal NADPH-dependent oxidoreductase which elevates intracellular concentrations of active glucocorticoids. Data obtained from mouse strains with genetically manipulated 11HSD1 showed that local metabolism of glucocorticoids plays an important role in the development of metabolic syndrome. Tissue specific dysregulation of 11HSD1 was also found in other models of metabolic syndrome as well as in a number of clinical studies. Here, we studied local glucocorticoid action in the liver, subcutaneous adipose tissue (SAT) and skeletal muscles of male and female Prague hereditary hypertriglyceridemic rats (HHTg) and their normotriglyceridemic counterpart, the Wistar rats. 11HSD1 bioactivity was measured as a conversion of [(3)H]11-dehydrocorticosterone to [(3)H]corticosterone or vice versa. Additionally to express level of active 11HSD1 protein, enzyme activity was measured in tissue homogenates. mRNA abundance of 11HSD1, hexoso-6-phosphate dehydrogenase (H6PDH) and the glucocorticoid receptor (GR) was measured by real-time PCR. In comparison with normotriglyceridemic animals, female HHTg rats showed enhanced regeneration of glucocorticoids in the liver and the absence of any changes in SAT and skeletal muscle. In contrast to females, the glucocorticoid regeneration in males of HHTg rats was unchanged in liver, but stimulated in SAT and downregulated in muscle. Furthermore, SAT and skeletal muscle exhibited not only 11-reductase but also 11-oxidase catalyzed by 11HSD1. In females of both strains, 11-oxidase activity largely exceeded 11-reductase activity. No dramatic changes were found in the mRNA expression of H6PDH and GR. Our data provide evidence that the relationship between hypertriglyceridemia and glucocorticoid action is complex and gender specific.

Correlative studies on the effects of obesity, diabetes and hypertension on gene expression in omental adipose tissue of obese women

OBJECTIVE

A major consequence of obesity is the enormous expansion of and enhanced inflammatory response seen in visceral adipose tissue. I hypothesized that the expression of inflammatory markers in visceral omental fat would correlate with the extent of visceral adiposity as measured by waist circumference or body mass index and that diabetes and hypertension, defined as subjects taking anti-hypertensive drugs, would be associated with changes in mRNA expression in visceral fat.

DESIGN AND METHODS

The expression of 106 mRNAs by RT-PCR was examined in observational studies using extracts of omental fat of obese women undergoing bariatric surgery as well as the circulating levels of some adipokines. We also compared the mRNA levels of 65 proteins in omental fat removed during gastric bypass surgery of women with and without hypertension and those with type 2 diabetes.

RESULTS

Out of 106 mRNAs the expression of 10 mRNAs in omental fat of women not taking anti-hypertensive drugs correlated with waist circumference while 7 different mRNAs had significant correlations with circulating glucose. The correlations of waist circumference with mRNA expression were abolished, except for interleukin (IL)-1 receptor antagonist (IL-1RA), in women taking anti-hypertensive drugs. The correlations of blood glucose with omental fat mRNA expression were abolished, except for that of Akt1 and Akt2, in women taking anti-hypertensive drugs. However, the expression of 4 different mRNAs in omental fat was affected by circulating glucose in subjects taking anti-hypertensive drugs. The circulating levels of IL-1 RA, but not fatty acid binding protein 4, adipsin and phospholipase A2, correlated with both waist circumference and mRNA expression in omental fat.

CONCLUSION

In female bariatric surgery patients, the mRNA expression of some proteins in omental fat was affected by the degree of obesity, whereas hypertension and diabetes affected a separate set of mRNAs.Nutrition and Diabetes (2011) 1, e17; doi:10.1038/nutd.2011.14; published online 26 September 2011.

Glucose ingestion selectively amplifies ACTH and cortisol secretory-burst mass and enhances their joint synchrony in healthy men

CONTEXT

Glucose intake is associated with a variable increase in adrenal glucocorticoid secretion.

HYPOTHESIS

Glucose ingestion elevates cortisol secretion by 1) augmenting pulsatile ACTH release; and/or 2) enhancing ACTH-cortisol synchrony or dose-responsiveness.

SUBJECTS

Fifty-eight healthy men ages 19-78 yr with computed tomography-estimated abdominal visceral fat participated in the study.

LOCATION

The study was conducted at the Clinical Translational-Research Center and Veterans Affairs Medical Center.

METHODS

We conducted frequent sampling of plasma ACTH and cortisol concentrations after glucose vs. water ingestion in the fasting state, as well as deconvolution, approximate entropy, linear-regression, and dose-response analysis.

OUTCOMES

After water ingestion, age was a negative correlate of the mass of ACTH (P = 0.009; R(2) = 0.119) and of cortisol (P < 0.001; R(2) = 0.269) secreted per burst. Glucose ingestion abolished both relationships but amplified pulsatile ACTH (P = 0.009) and cortisol (P = 0.001) secretion. Glucose exposure selectively augmented the mass of ACTH (P < 0.001) and of cortisol (P = 0.004) secreted per burst without altering burst number or basal secretion. The increment in pulsatile ACTH strongly predicted the increment in pulsatile cortisol (P < 10(-4); R(2) = 0.325) secretion. Abdominal visceral fat positively forecast the glucose-induced increment in cortisol secretory-burst mass (P = 0.019). According to approximate entropy analysis, glucose input also enhanced the joint synchrony of ACTH-cortisol secretory patterns (P ≤ 0.001). Caloric intake did not affect analytical dose-response estimates of ACTH potency and efficacy or adrenal sensitivity.

CONCLUSION

Conjoint augmentation of the mass of ACTH and cortisol secreted per burst and enhancement of ACTH-cortisol synchrony underlie glucose-induced glucocorticoid secretion in healthy men. Visceral adiposity is a predictor of the glucose-stimulated increment in burst-like cortisol output, suggesting an additional possible mechanism for increased cardiovascular risk in abdominal obesity.

11β-hydroxysteroid dehydrogenases and the brain: from zero to hero, a decade of progress

Glucocorticoids have profound effects on brain development and adult CNS function. Excess or insufficient glucocorticoids cause myriad abnormalities from development to ageing. The actions of glucocorticoids within cells are determined not only by blood steroid levels and target cell receptor density, but also by intracellular metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSD). 11β-HSD1 regenerates active glucocorticoids from their inactive 11-keto derivatives and is widely expressed throughout the adult CNS. Elevated hippocampal and neocortical 11β-HSD1 is observed with ageing and causes cognitive decline; its deficiency prevents the emergence of cognitive defects with age. Conversely, 11β-HSD2 is a dehydrogenase, inactivating glucocorticoids. The major central effects of 11β-HSD2 occur in development, as expression of 11β-HSD2 is high in fetal brain and placenta. Deficient feto-placental 11β-HSD2 results in a life-long phenotype of anxiety and cardiometabolic disorders, consistent with early life glucocorticoid programming.

Dietary manipulation reveals an unexpected inverse relationship between fat mass and adipose 11β-hydroxysteroid dehydrogenase type 1

Increased dietary fat intake is associated with obesity, insulin resistance, and metabolic disease. In transgenic mice, adipose tissue-specific overexpression of the glucocorticoid-amplifying enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) exacerbates high-fat (HF) diet-induced visceral obesity and diabetes, whereas 11β-HSD1 gene knockout ameliorates this, favoring accumulation of fat in nonvisceral depots. Paradoxically, in normal mice HF diet-induced obesity (DIO) is associated with marked downregulation of adipose tissue 11β-HSD1 levels. To identify the specific dietary fats that regulate adipose 11β-HSD1 and thereby impact upon metabolic disease, we either fed mice diets enriched (45% calories as fat) in saturated (stearate), monounsaturated (oleate), or polyunsaturated (safflower oil) fats ad libitum or we pair fed them a low-fat (11%) control diet for 4 wk. Adipose and liver mass and glucocorticoid receptor and 11β-HSD1 mRNA and activity levels were determined. Stearate caused weight loss and hypoinsulinemia, partly due to malabsorption, and this markedly increased plasma corticosterone levels and adipose 11β-HSD1 activity. Oleate induced pronounced weight gain and hyperinsulinemia in association with markedly low plasma corticosterone and adipose 11β-HSD1 activity. Weight gain and hyperinsulinemia was less pronounced with safflower compared with oleate despite comparable suppression of plasma corticosterone and adipose 11β-HSD1. However, with pair feeding, safflower caused a selective reduction in visceral fat mass and relative insulin sensitization without affecting plasma corticosterone or adipose 11β-HSD1. The dynamic depot-selective relationship between adipose 11β-HSD1 and fat mass strongly implicates a dominant physiological role for local tissue glucocorticoid reactivation in fat mobilization.

Expression of 11β-hydroxysteroid dehydrogenase type 1 in visceral and subcutaneous adipose tissues of patients with polycystic ovary syndrome is associated with adiposity

Polycystic ovary syndrome (PCOS) is characterized by insulin resistance (IR) and central obesity. The impact of adipose tissue cortisol reactivation by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) on markers of obesity and IR was assessed in PCOS patients. Eighty-five PCOS patients and 43 controls were enrolled for subcutaneous adipose tissue biopsy; 25/85 patients and 29/43 controls underwent also visceral adipose tissue biopsy. HSD11B1 gene expression and expression of lipid metabolism genes were measured in subcutaneous and visceral adipose tissues. Anthropometric and biochemical markers of IR and PCOS were also assessed. HSD11B1 expression in visceral and subcutaneous adipose tissue was increased in PCOS patients compared to controls (p<0.05). After BMI adjustment, the difference was no longer significant. In PCOS patients, visceral HSD11B1 expression correlated positively with waist circumference (p=0.001), BMI (p=0.002), plasma insulin (p<0.05), systolic blood pressure (p=0.003), and lipoprotein lipase (LPL), hormone-sensitive lipase (LIPE) and peroxisome-proliferator activated receptor γ gene expression. Subcutaneous HSD11B1 expression correlated positively with BMI, waist circumference (p<0.001 for both) and HOMA-IR (p=0.003), and negatively with LPL, LIPE, adiponectin and glucose transporter GLUT4 gene expression. HSD11B1 expression in both depots showed a negative correlation with plasma HDL-cholesterol (p<0.03) and a positive one with C-reactive protein (p<0.001). In multiple regression analysis, HSD11B1 expression in visceral adipose tissue was most prominently associated with waist circumference, and that in subcutaneous adipose tissue with BMI (p<0.001 for both). Our results show that PCOS is not associated with increased HSD11B1 expression once adiposity is controlled for. Increased expression of this gene correlates with markers of adiposity and predicts IR and an unfavorable metabolic profile, independently of PCOS.

Adipocyte morphometric evaluation and angiogenesis in the omentum transposed to the breast: a preliminary study

OBJECTIVE

The purpose of this study was to describe the probable mechanism of the volume increase of laparoscopically harvested omentum flaps used to treat breast deformities.

METHODS

A histological analysis of omentum samples was performed to study the volume increase of laparoscopically harvested omentum flaps. Samples were harvested immediately after the transposition of the omentum from the abdominal cavity to the breast region and during the second surgical procedure for breast symmetrization of eight patients submitted to the transposition of the omentum flap. Changes in the morphometric measurements of the adipocytes (perimeter, diameter, and area), microvascular density (as measured by the CD31 endothelial marker), and immunohistochemical expression of VEGF were documented.

RESULTS

The increases in adipocyte size and microvascular density were statistically significant (P < 0.012). The expression levels of VEGF were lower in the second set of samples when compared to the first set, but the differences were not statistically significant (P < 0.093).

CONCLUSION

These results demonstrate an increase in cellular volume as measured by adipocyte perimeter, diameter, and area. Moreover, the increase in the number of vessels in the second set of samples suggests that neoangiogenesis was stimulated by the initial increase in VEGF expression levels observed in the first set of samples. The increase in VEGF expression in the flap may have been caused by adipocyte hypertrophy resulting from neoangiogenesis.

Adipose tissue and ceramide biosynthesis in the pathogenesis of obesity

Although obesity is a complex metabolic disorder often associated with insulin resistance, hyperinsulinemia and Type 2 diabetes, as well as with accelerated atherosclerosis, the molecular changes in obesity that promote these disorders are not completely understood. Several mechanisms have been proposed to explain how increased adipose tissue mass affects whole body insulin resistance and cardiovascular risk. One theory is that increased adipose derived inflammatory cytokines induces a chronic inflammatory state that not only increases cardiovascular risk, but also antagonizes insulin signaling and mitochondrial function and thereby impair glucose hemostasis. Another suggests that lipid accumulation in nonadipose tissues not suited for fat storage leads to the buildup of bioactive lipids that inhibit insulin signaling and metabolism. Recent evidence demonstrates that sphingolipid metabolism is dysregulated in obesity and specific sphingolipids may provide a common pathway that link excess nutrients and inflammation to increased metabolic and cardiovascular risk. This chapter will focus primarily on the expression and regulation of adipose and plasma ceramide biosynthesis in obesity and, its potential contribution to the pathogenesis of obesity and the metabolic syndrome.

Adipogenic and lipolytic effects of chronic glucocorticoid exposure

Glucocorticoids have been proposed to be both adipogenic and lipolytic in action within adipose tissue, although it is unknown whether these actions can occur simultaneously. Here we investigate both the in vitro and in vivo effects of corticosterone (Cort) on adipose tissue metabolism. Cort increased 3T3-L1 preadipocyte differentiation in a concentration-dependent manner, but did not increase lipogenesis in adipocytes. Cort increased lipolysis within adipocytes in a concentration-dependent manner (maximum effect at 1-10 μM). Surprisingly, removal of Cort further increased lipolytic rates (∼320% above control, P < 0.05), indicating a residual effect on basal lipolysis. mRNA and protein expression of adipose triglyceride lipase and phosphorylated status of hormone sensitive lipase (Ser563/Ser660) were increased with 48 h of Cort treatment. To test these responses in vivo, Sprague-Dawley rats were subcutaneously implanted with wax pellets with/without Cort (300 mg). After 10 days, adipose depots were removed and cultured ex vivo. Both free fatty acids and glycerol concentrations were elevated in fed and fasting conditions in Cort-treated rats. Despite increased lipolysis, Cort rats had more visceral adiposity than sham rats (10.2 vs. 6.9 g/kg body wt, P < 0.05). Visceral adipocytes from Cort rats were smaller and more numerous than those in sham rats, suggesting that adipogenesis occurred through preadipocyte differentiation rather than adipocyte hypertrophy. Visceral, but not subcutaneous, adipocyte cultures from Cort-treated rats displayed a 1.5-fold increase in basal lipolytic rates compared with sham rats (P < 0.05). Taken together, our findings demonstrate that chronic glucocorticoid exposure stimulates both lipolysis and adipogenesis in visceral adipose tissue but favors adipogenesis primarily through preadipocyte differentiation.

Expression of genes related to glucocorticoid action in human subcutaneous and omental adipose tissue

Adipose tissue glucocorticoid action relies on local enzymatic interconversion and glucocorticoid receptor (GR) availability. 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1), 2 (11β-HSD2) and hexose-6-phosphate dehydrogenase (H6PDH) are likely involved in glucocorticoid activation/inactivation within adipose tissue. We examined adipose tissue mRNA expression of genes related to glucocorticoid action and their association with total and visceral adiposity. Messenger RNA was measured in paired subcutaneous and omental fat samples obtained from 56 women (age: 47.3 ± 4.8 years, BMI: 27.1 ± 5.2 kg/m(2)) undergoing gynaecological surgery. Expression levels of 11β-HSD2, H6PDH and GRα were higher in omental adipose tissue while 11β-HSD1 expression was similar between fat compartments. Subcutaneous and omental 11β-HSD1 mRNA abundances were positively associated with total and visceral adiposity whereas omental H6PDH mRNA abundance was negatively associated with these measures. Only omental 11β-HSD1 mRNA expression remained significantly associated with visceral adipose tissue area following statistical adjustment for fat mass, age and menopausal status. Omental 11β-HSD1 mRNA expression explained 19.1% of the variance in visceral adipose tissue area. Omental fat tissue 11β-HSD-1 protein and cortisol levels were higher in visceral obese women, supporting findings obtained with 11β-HSD-1 mRNA. These results suggest that among the transcripts examined only omental 11β-HSD1 is independently associated with visceral obesity in women.

Targeting the pre-receptor metabolism of cortisol as a novel therapy in obesity and diabetes

Due to its impact upon health and the economy, the mechanisms that contribute to the pathogenesis of obesity and the metabolic syndrome are under intense scrutiny. In addition to understanding the pathogenesis of disease it is important to design and trial novel therapies. Patients with cortisol excess, Cushing's syndrome, have a phenotype similar to that of the metabolic syndrome and as a result there is much interest the manipulation of glucocorticoid (GC) action as a therapeutic strategy. Intracellular GC levels are regulated by 11β-hydroxysteroid dehydrogenase (11β-HSD1) which converts inactive cortisone to cortisol, thereby increasing local GC action. There is an abundance of data implicating 11β-HSD1 in the pathogenesis of obesity, type 2 diabetes and the metabolic syndrome and 11β-HSD1 is an attractive therapeutic target. Selective 11β-HSD1 inhibitors, which do not act upon 11β-HSD2 (which inactivates cortisol to cortisone) are in development. So far studies have primarily been carried out in rodents, with results showing improvements in metabolic profile. Data are now beginning to emerge from human studies and the results are promising.

Brief review: glucocorticoid excretion in obesity

Cortisol secretion and glucocorticoid excretion rates are regularly increased in obesity and associate with indices of body size and visceral adiposity. Different mechanisms may underlie the elevated urinary excretion rates of cortisol metabolites in obesity. In the present brief overview, potential mechanisms are discussed, paying special attention to cortisol metabolism. Besides, potential confounding factors in the evaluation of urinary glucocorticoid excretion are highlighted.

Is metabolic syndrome a mild form of Cushing's syndrome?

The Metabolic Syndrome is a diagnosis of increasing prevalence that is noted to share multiple clinical features with Cushing's syndrome. Several studies suggest abnormalities in the Hypothalamic-Pituitary-Adrenal axis to be associated with this disease and tissue-specific hypercortisolemia is being investigated as a possible contributing factor. More research is needed to explore the relation between cortisol and the metabolic syndrome which, if confirmed, will have major therapeutic and public health implications.