Obesity is accompanied by disturbances in peripheral glucocorticoid metabolism and changes in FA recycling

Estrogens in Adipose Tissue Physiology and Obesity-Related Dysfunction

Menopause-related decline in estrogen levels is accompanied by a change in adipose tissue distribution from a gynoid to an android and an increased prevalence of obesity in women. These unfavorable phenomena can be partially restored by hormone replacement therapy, suggesting a significant role for estrogen in the regulation of adipocytes' function. Indeed, preclinical studies proved the involvement of these hormones in adipose tissue development, metabolism, and inflammatory activity. However, the relationship between estrogen and obesity is bidirectional. On the one hand-their deficiency leads to excessive fat accumulation and impairs adipocyte function, on the other-adipose tissue of obese individuals is characterized by altered expression of estrogen receptors and key enzymes involved in their synthesis. This narrative review aims to summarize the role of estrogen in adipose tissue development, physiology, and in obesity-related dysfunction. Firstly, the estrogen classification, synthesis, and modes of action are presented. Next, their role in regulating adipogenesis and adipose tissue activity in health and the course of obesity is described. Finally, the potential therapeutic applications of estrogen and its derivates in obesity treatment are discussed.

Effects of ACTH-Induced Long-Term Hypercortisolism on the Transcriptome of Canine Visceral Adipose Tissue

Cushing’s syndrome, or hypercortisolism (HC), a common endocrinopathy in adult dogs, is caused by chronic hypercortisolemia. Among different metabolic disorders, this syndrome is associated with enhanced subcutaneous lipolysis and visceral adiposity. However, effects of HC in adipose tissue, especially regarding visceral adipose tissue (VAT), are still poorly understood. Herein, the transcriptomic effects of chronic HC on VAT of dogs were evaluated. For this, subcutaneously implanted ACTH-releasing pumps were used, followed by deep RNA sequencing of the canine VAT. Prolonged HC seems to affect a plethora of regulatory mechanisms in VAT of treated dogs, with 1190 differentially expressed genes (DEGs, p and FDR < 0.01) being found. The 691 downregulated DEGs were mostly associated with functional terms like cell adhesion and migration, intracellular signaling, immune response, extracellular matrix and angiogenesis. Treatment also appeared to modulate local glucocorticoid and insulin signaling and hormonal sensitivity, and several factors, e.g., TIMP4, FGF1, CCR2, CXCR4 and HSD11B1/2, were identified as possible important players in the glucocorticoid-related expansion of VAT. Modulation of their function during chronic HC might present interesting targets for further clinical studies. Similarities in the effects of chronic HC on VAT of dogs and humans are highlighted.

Bone Mineral Density, Parathyroid Hormone, and Vitamin D After Gastric Bypass Surgery: a 10-Year Longitudinal Follow-Up

Background

The aim of the present study was to study longitudinal changes in bone mineral density (BMD), vitamin D, and parathyroid hormone (PTH) levels in females over a 10-year period after laparoscopic Roux-en-Y gastric bypass (LRYGB).

Methods

Twenty-three women, mean age 43.4 ± 8.7 years and mean body mass index (BMI) 44.6 ± 5.17 kg/m² at baseline, were included. BMD, BMI, S-calcium, S-25(OH)-vitamin D, and fP-PTH were measured preoperatively and 2, 5, and 10 years postoperatively.

Results

Ten years after surgery, BMD of the spine and femoral neck decreased by 20% and 25%, respectively. Changes in serum levels of vitamin D, PTH, and calcium over the same period were small.

Conclusion

After LRYGB with subsequent massive weight loss, a large decrease in BMD of the spine and femoral neck was seen over a 10-year postoperative period. The fall in BMD largely occurred over the first 5 years after surgery.

The effect of diet-induced obesity and pasture on blood pressure and serum cortisol in Standardbred mares

BACKGROUND

Obesity is associated with insulin resistance, vascular dysfunction and altered cortisol metabolism both in humans and in horses.

OBJECTIVES

Evaluate the effect of weight gain induced by a haylage diet low in nonstructural carbohydrates (NSC) on insulin sensitivity, blood pressure and serum cortisol concentrations.

STUDY DESIGN

In vivo experiment.

METHODS

Nine adult Standardbred mares fed a fat supplemented haylage diet at 250% of the horses' daily metabolisable energy requirements for 22 weeks. Horses were then turned out on pasture for 4 weeks. Insulin sensitivity (SI_CLAMP ) was measured before and after weight gain and after 4 weeks of pasture using the euglycemic hyperinsulinaemic clamp (EHC) method. Body condition score (BCS), blood pressure and serum cortisol were monitored throughout the study. All data were analysed using the linear mixed model procedure. Values of P < 0.05 were considered as statistically different.

RESULTS

All horses became obese during the weight gain period (BCS> 7). Mean arterial blood pressure (MAP) increased during the weight gain period and was significantly higher than initial values at the end of the weight gain period (78 ± 3 mm Hg vs 92 ± 3 mmHg). MAP remained increased on pasture (93 ± 3 mmHg). SI_CLAMP was unaffected by weight gain 0.9 ± 0.1 vs 1.0 ± 0.1 ([mg/kg/min × 10³ ]/[µIU/mL × mmol/L])) but improved after pasture (1.6 ± 0.1 ([mg/kg/min × 10³ ]/ [mU/L]). Serum cortisol concentrations increased during the weight gain period (80 ± 9 nmol/L vs 112 ± 9 nmol/L) and remained increased during pasture.

MAIN LIMITATIONS

Limited number of horses and no control group.

CONCLUSIONS

Obesity was associated with a linear increase in blood pressure and an increase in serum cortisol that was not associated with insulin sensitivity.

The glucocorticoid receptor in brown adipocytes is dispensable for control of energy homeostasis

Aberrant activity of the glucocorticoid (GC)/glucocorticoid receptor (GR) endocrine system has been linked to obesity-related metabolic dysfunction. Traditionally, the GC/GR axis has been believed to play a crucial role in adipose tissue formation and function in both, white (WAT) and brown adipose tissue (BAT). While recent studies have challenged this notion for WAT, the contribution of GC/GR signaling to BAT-dependent energy homeostasis remained unknown. Here, we have generated and characterized a BAT-specific GR-knockout mouse (GR^BATKO ), for the first time allowing to genetically interrogate the metabolic impact of BAT-GR. The HPA axis in GR^BATKO mice was intact, as was the ability of mice to adapt to cold. BAT-GR was dispensable for the adaptation to fasting-feeding cycles and the development of diet-induced obesity. In obesity, glucose and lipid metabolism, insulin sensitivity, and food intake remained unchanged, aligning with the absence of changes in thermogenic gene expression. Together, we demonstrate that the GR in UCP1-positive BAT adipocytes plays a negligible role in systemic metabolism and BAT function, thereby opposing a long-standing paradigm in the field.

Effect of Gastric Bypass on Bone Mineral Density, Parathyroid Hormone and Vitamin D: 5 Years Follow-up

BACKGROUND

The aim of the present study was to see if there are longitudinal changes in bone mineral density (BMD), vitamin D or parathyroid hormone (PTH) in females 5 years after Laparoscopic Roux-en-Y Gastric Bypass (LRYGB).

METHODS

Thirty-two women with mean age 41.6 ± 9.3 years and mean body mass index (BMI) 44.5 ± 4.6 kg/m(2) were included. Preoperatively, 2 and 5 years postoperatively, BMD, weight, height, S-calcium, S-albumin, S-creatinine, S-25(OH)-vitamin D and fP-PTH were measured.

RESULTS

The mean decrease in BMI between baseline and 5 years after surgery was 29.4%. BMD of the spine and femur measured as z- and t-scores, showed a linear, statistically significant declining trend over the years. The fall in BMD of the spine and femoral neck between baseline and 5 years after surgery was 19 and 25%, respectively. The mean fP-PTH showed a significant increase over the study period (20.2 μg/L increase, 95% CI:-31.99 to -8.41). S-calcium, both free and corrected for albumin, showed a decrease between baseline and 5 years after surgery. Eight patients developed osteopenia and one osteoporosis after a 5-year follow-up.

CONCLUSION

LRYGB is an efficient method for sustained long-term body weight loss. There is, however, a concomitant decrease in BMD and S-calcium, and an increase in fP-PTH.

Mechanisms of estrogen protection in diabetes and metabolic disease

Until menopause, women are largely protected against several metabolic disorders, implicating a role for sex hormones. Adiposity and insulin resistance are fundamental features in the pathogenesis of type 2 diabetes mellitus. Emerging data suggest that sex-steroid hormones and adipocyte-derived hormones and cytokines could be associated with type 2 diabetes risk and that some of these novel markers can exhibit a sexual dimorphism with regard to this risk. Evidence suggests that the female hormone, 17β-estradiol protects insulin production and prevents diabetes. Although 17β-estradiol acts primarily via two distinct estrogen receptors (ERs), ERα and ERβ, it appears that ERα protects β-cell survival, whereas ERβ reduces ERα function and provokes β-cell apoptosis. Accordingly, use of menopausal hormone therapy has been shown to reduce diabetes incidence and weight gain. Recent findings that benefits of menopausal hormone therapy might not outweigh the risks in some women do not negate the importance of identifying mechanisms by which 17β-estradiol attenuates the development and progression of metabolic disease. This could lay the ground to the design of pharmacological treatments for the prevention of menopause-associated metabolic disorders that are safer and more efficacious than current hormone-based regimens.

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.

Association of 11β-hydroxysteroid dehydrogenase type I expression and activity with estrogen receptor β in adipose tissue from postmenopausal women

OBJECTIVE

11β-Hydroxysteroid dehydrogenase type I (11βHSD1) regenerates active cortisol from inert cortisone in adipose tissue. Elevated adipose tissue 11βHSD1 activity is observed in obese humans and rodents, where it is linked to obesity and its metabolic consequences. Menopause is also associated with increased abdominal fat accumulation, suggesting that estrogen is also important in adipose tissue metabolism. The purpose of this current study was to establish whether estrogen signaling through estrogen receptor α (ER-α) and estrogen receptor β (ER-β) could influence 11βHSD1 in premenopausal and postmenopausal adipose tissues.

METHODS

Nineteen premenopausal (aged 26 ± 5 y; body mass index, 23.6 ± 1.6 kg/m) and 23 postmenopausal (aged 63 ± 4 y; body mass index, 23.4 ± 1.9 kg/m) healthy women were studied. Subcutaneous adipose tissue biopsies and fasting venous blood samples were taken. Body composition was measured by bioelectrical impedance analysis. Human Simpson-Golabi-Behmel syndrome adipocyte cells were treated with ER-α- and ER-β-specific agonists for 24 hours. Basic anthropometric data, serum 17β-estradiol and progesterone concentrations, ER-α and ER-β messenger RNA (mRNA) levels, and 11βHSD1 mRNA, protein, and activity levels were assessed.

RESULTS

ER-β and 11βHSD1, but not ER-α, mRNAs were significantly increased in adipose tissue from postmenopausal women compared with premenopausal women. ER-β had a significant positive correlation with the mRNA level of 11βHSD1 in adipose tissue from premenopausal and postmenopausal women. This association between ER-β and 11βHSD1 was greatest in adipose tissue from postmenopausal women. In human Simpson-Golabi-Behmel syndrome adipocytes, diarylpropiolnitrile, a selective ER-β agonist, increased 11βHSD1 mRNA, protein, and activity levels.

CONCLUSIONS

We conclude that, in adipose tissue, ER-β-mediated estrogen signaling can up-regulate 11βHSD1 and that this may be of particular importance in postmenopausal women.

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.

Obesity and burns

The population of overweight patients presenting to burn facilities is expected to increase significantly over the next decades due to the global epidemic of obesity. Excess adiposity mediates alterations to key physiological responses and poses challenges to the optimal management of burns. The purpose of this study is to document the general epidemiological aspects of thermal injuries in the obese population, outline relevant physiological aspects associated with obesity, and draw attention to topics relating to the management, rehabilitation, and prognosis of burns in this emerging subpopulation of patients.

11β-Hydroxysteroid dehydrogenase type 1: relevance of its modulation in the pathophysiology of obesity, the metabolic syndrome and type 2 diabetes mellitus

Recent evidence strongly argues for a pathogenic role of glucocorticoids and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in obesity and the metabolic syndrome, a cluster of risk factors for atherosclerotic cardiovascular disease and type 2 diabetes mellitus (T2DM) that includes insulin resistance (IR), dyslipidaemia, hypertension and visceral obesity. This has been partially prompted not only by the striking clinical resemblances between the metabolic syndrome and Cushing's syndrome (a state characterized by hypercortisolism that associates with metabolic syndrome components) but also from monogenic rodent models for the metabolic syndrome (e.g. the leptin-deficient ob/ob mouse or the leptin-resistant Zucker rat) that display overall increased secretion of glucocorticoids. However, systemic circulating glucocorticoids are not elevated in obese patients and/or patients with metabolic syndrome. The study of the role of 11β-HSD system shed light on this conundrum, showing that local glucocorticoids are finely regulated in a tissue-specific manner at the pre-receptor level. The system comprises two microsomal enzymes that either activate cortisone to cortisol (11β-HSD1) or inactivate cortisol to cortisone (11β-HSD2). Transgenic rodent models, knockout (KO) for HSD11B1 or with HSD11B1 or HSD11B2 overexpression, specifically targeted to the liver or adipose tissue, have been developed and helped unravel the currently undisputable role of the enzymes in metabolic syndrome pathophysiology, in each of its isolated components and in their prevention. In the transgenic HSD11B1 overexpressing models, different features of the metabolic syndrome and obesity are replicated. HSD11B1 gene deficiency or HSD11B2 gene overexpression associates with improvements in the metabolic profile. In face of these demonstrations, research efforts are now being turned both into the inhibition of 11β-HSD1 as a possible pharmacological target and into the role of dietary habits on the establishment or the prevention of the metabolic syndrome, obesity and T2DM through 11β-HSD1 modulation. We intend to review and discuss 11β-HSD1 and obesity, the metabolic syndrome and T2DM and to highlight the potential of its inhibition for therapeutic or prophylactic approaches in those metabolic diseases.

Liver upregulation of genes involved in cortisol production and action is associated with metabolic syndrome in morbidly obese patients

BACKGROUND

Hepatic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity, which converts cortisone (inactive) to cortisol, is downregulated in obesity. However, this compensation fails in obese with metabolic abnormalities, such as diabetes. To further characterize the tissue-specific cortisol regeneration in obesity, we have investigated the mRNA expression of genes related to local cortisol production, i.e., 11β-HSD1, hexose-6-phosphate dehydrogenase (H6PDH) and cortisol action, glucocorticoid receptor (GR) and a cortisol target gene, phosphoenolpyruvate carboxykinase (PEPCK) in the liver, and visceral (VAT) and subcutaneous (SAT) adipose tissues from morbidly obese patients with and without metabolic syndrome (MS).

METHODS

Fifty morbidly obese patients undergoing bariatric surgery, 14 men (mean age, 41.3 ± 3.5 years; BMI, 48.0 ± 3.6 kg/m(2)) and 36 women (mean age, 44.6 ± 1.9 years; BMI, 44.9 ± 1.2 kg/m(2)), were classified as having MS (MS+, n = 20) or not (MS-, n = 30). Tissue mRNA levels were measured by real-time polymerase chain reaction.

RESULTS

Hepatic mRNA levels of these genes were higher in obese patients with MS (11β-HSD1, P = 0.002; H6PDH, P = 0.043; GR, P = 0.033; PEPCK, P = 0.032) and positively correlated with the number of clinical characteristics that define the MS. The expression of the four genes positively correlated among them. In contrast to the liver, these genes were not differently expressed in VAT or SAT, when MS+ and MS- obese patients were compared.

CONCLUSIONS

Coordinated liver-specific upregulation of genes involved in local cortisol regeneration and action support the concept that local hepatic hypercortisolism contributes to development of MS in morbidly obese patients.

G6PT-H6PDH-11βHSD1 triad in the liver and its implication in the pathomechanism of the metabolic syndrome

The metabolic syndrome, one of the most common clinical conditions in recent times, represents a combination of cardiometabolic risk determinants, including central obesity, glucose intolerance, insulin resistance, dyslipidemia, non-alcoholic fatty liver disease and hypertension. Prevalence of the metabolic syndrome is rapidly increasing worldwide as a consequence of common overnutrition and consequent obesity. Although a unifying picture of the pathomechanism is still missing, the key role of the pre-receptor glucocorticoid activation has emerged recently. Local glucocorticoid activation is catalyzed by a triad composed of glucose-6-phosphate-transporter, hexose-6-phosphate dehydrogenase and 11β-hydroxysteroid dehydrogenase type 1 in the endoplasmic reticulum. The elements of this system can be found in various cell types, including adipocytes and hepatocytes. While the contribution of glucocorticoid activation in adipose tissue to the pathomechanism of the metabolic syndrome has been well established, the relative importance of the hepatic process is less understood. This review summarizes the available data on the role of the hepatic triad and its role in the metabolic syndrome, by confronting experimental findings with clinical observations.

Green tea extract suppresses NFκB activation and inflammatory responses in diet-induced obese rats with nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is characterized by oxidative stress and inflammatory responses that exacerbate liver injury. The objective of this study was to determine whether the antioxidant and antiinflammatory activities of green tea extract (GTE) would protect against NASH in a model of diet-induced obesity. Adult Wistar rats were fed a low-fat (LF) diet or high-fat (HF) diet containing no GTE or GTE at 1% or 2% (HF+2GTE) for 8 wk. The HF group had greater (P ≤ 0.05) serum alanine (ALT) and aspartate aminotransferases and hepatic lipids than the LF group. Both GTE groups had lower ALT and hepatic lipid than the HF group. In liver and epididymal adipose, the HF group had lower glutathione as well as greater mRNA and protein expression of TNFα and monocyte chemoattractant protein-1 (MCP-1) and NFκB binding activity than the LF group. Compared to the HF group, the HF+2GTE group had greater glutathione and lower protein and mRNA levels of inflammatory cytokines in both tissues. NFκB binding activities at liver and adipose were also lower, likely by inhibiting the phosphorylation of inhibitor of NFκB. NFκB binding activities in liver and adipose (P ≤ 0.05; r = 0.62 and 0.46, respectively) were correlated with ALT, and hepatic NFκB binding activity was inversely related to liver glutathione (r = -0.35). These results suggest that GTE-mediated improvements in glutathione status are associated with the inhibition of hepatic and adipose inflammatory responses mediated by NFκB, thereby protecting against NASH.

Weight loss after gastric bypass surgery in women is followed by a metabolically favorable decrease in 11beta-hydroxysteroid dehydrogenase 1 expression in subcutaneous adipose tissue

BACKGROUND AND AIMS

The role of 11beta-hydroxysteroid dehydrogenase 1 (11beta-HSD1) in the pathogenesis of obesity has been elucidated in humans and in various rodent models. Obesity is accompanied by disturbances in glucocorticoid metabolism, circulating adipokine levels, and fatty acid (FA) reesterification. This study was undertaken to evaluate glucocorticoid metabolism in sc fat before and after weight loss and to explore putative associations between 11beta-HSD1 and leptin, adiponectin, and FA recycling.

SUBJECTS AND METHODS

Twenty-seven obese (mean body mass index 44.4 + or - 4.4 kg/m(2)) women underwent gastric bypass surgery. Subcutaneous fat biopsies were collected before and 2 yr after surgery. The expression of 11beta-HSD1, leptin, adiponectin, and phosphoenolpyruvate carboxykinase (PEPCK) mRNA was evaluated with real-time PCR. Serum leptin and adiponectin protein levels were estimated by ELISA.

RESULTS

Two years after gastric bypass surgery, significant reductions were observed in the mean body mass index (from 44.4 to 30.8 kg/m(2)) and mean waist circumference (from 121.9 to 90.6 cm). After weight loss, 11beta-HSD1 mRNA expression decreased 4-fold (P < 0.001). Both leptin and adiponectin mRNA expression decreased, with concomitantly decreased circulating leptin and increased circulating adiponectin levels. PEPCK mRNA expression did not change.

CONCLUSION

Weight loss after gastric bypass surgery was followed by metabolically favorable changes in insulin sensitivity, circulating leptin and adiponectin, and peripheral glucocorticoid metabolism. A significant reduction in 11beta-HSD1 expression was observed in sc adipose tissue after weight loss. This suggests that up-regulation of 11beta-HSD1 is a consequence, rather than a cause, of obesity.

Testosterone stimulates adipose tissue 11beta-hydroxysteroid dehydrogenase type 1 expression in a depot-specific manner in children

CONTEXT

Activation of the enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) in adipose tissue results in the production of excess tissue glucocorticoids and the induction of adiposity and visceral obesity in particular. Androgens may affect body fat distribution by regulating the local metabolism of cortisol.

OBJECTIVE

Our objective was to study 11beta-HSD1 mRNA expression in abdominal sc and omental (om) adipose tissue in children after in vitro testosterone and cortisol treatment.

SUBJECTS AND METHODS

Paired fat biopsies (sc and om) were obtained from 19 boys (age 6-14 yr, body mass index 14.6-25.3 kg/m(2), BMI sd score SDS -1.6-3.1) undergoing open abdominal surgery. Pieces of adipose tissue were incubated with testosterone, cortisol, or both hormones for 24 h, whereupon mRNA expression of 11beta-HSD1 and hexose-6-phosphate dehydrogenase (H6PDH) were measured by real-time PCR, and 11beta-HSD1 enzyme activity was determined.

RESULTS

Testosterone treatment up-regulated 11beta-HSD1 mRNA expression compared with control incubations in the absence of testosterone (P < 0.05) in om adipose tissue. Testosterone and cortisol both increased 11beta-HSD1 mRNA expression in om but not sc adipose tissue in a depot-specific manner by 2.5- and 2.9-fold, respectively (P < 0.001). However, there was no synergistic effect of the two hormones. 11beta-HSD1 enzyme activity correlated positively to mRNA expression (r = 0.610; P = 0.001). Adipose tissue mRNA expression of H6PDH was affected in a similar fashion to 11beta-HSD1 after hormonal treatment.

CONCLUSIONS

Testosterone and cortisol stimulated 11beta-HSD1 and H6PDH mRNA expression and 11beta-HSD1 activity in om but not in sc adipose tissue. This suggests that these hormones may contribute to fat distribution and accumulation during childhood.

Gut microbiota in obesity and metabolic disorders

Obesity is a major public health issue as it is causally related to several chronic disorders, including type-2 diabetes, CVD and cancer. Novel research shows that the gut microbiota is involved in obesity and metabolic disorders, revealing that obese animal and human subjects have alterations in the composition of the gut microbiota compared to their lean counterparts. Moreover, transplantation of the microbiota of either obese or lean mice influences body weight in the germ-free recipient mice, suggesting that the gut ecosystem is a relevant target for weight management. Indigenous gut microbes may regulate body weight by influencing the host's metabolic, neuroendocrine and immune functions. The intestinal microbiota, as a whole, provides additional metabolic functions and regulates the host's gene expression, improving the ability to extract and store energy from the diet and contributing to body-weight gain. Imbalances in the gut microbiota and increases in plasma lipopolysaccharide may also act as inflammatory factors related to the development of atherosclerosis, insulin resistance and body-weight gain. In contrast, specific probiotics, prebiotics and related metabolites might exert beneficial effects on lipid and glucose metabolism, the production of satiety peptides and the inflammatory tone related to obesity and associated metabolic disorders. This knowledge is contributing to our understanding of how environmental factors influence obesity and associated diseases, providing new opportunities to design improved dietary intervention strategies to manage these disorders.

Tissue-specific increases in 11beta-hydroxysteroid dehydrogenase type 1 in normal weight postmenopausal women

With age and menopause there is a shift in adipose distribution from gluteo-femoral to abdominal depots in women. Associated with this redistribution of fat are increased risks of type 2 diabetes and cardiovascular disease. Glucocorticoids influence body composition, and 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) which converts inert cortisone to active cortisol is a putative key mediator of metabolic complications in obesity. Increased 11βHSD1 in adipose tissue may contribute to postmenopausal central obesity. We hypothesized that tissue-specific 11βHSD1 gene expression and activity are up-regulated in the older, postmenopausal women compared to young, premenopausal women. Twenty-three pre- and 23 postmenopausal, healthy, normal weight women were recruited. The participants underwent a urine collection, a subcutaneous adipose tissue biopsy and the hepatic 11βHSD1 activity was estimated by the serum cortisol response after an oral dose of cortisone. Urinary (5α-tetrahydrocortisol+5β-tetrahydrocortisol)/tetrahydrocortisone ratios were higher in postmenopausal women versus premenopausal women in luteal phase (P<0.05), indicating an increased whole-body 11βHSD1 activity. Postmenopausal women had higher 11βHSD1 gene expression in subcutaneous fat (P<0.05). Hepatic first pass conversion of oral cortisone to cortisol was also increased in postmenopausal women versus premenopausal women in follicular phase of the menstrual cycle (P<0.01, at 30 min post cortisone ingestion), suggesting higher hepatic 11βHSD1 activity. In conclusion, our results indicate that postmenopausal normal weight women have increased 11βHSD1 activity in adipose tissue and liver. This may contribute to metabolic dysfunctions with menopause and ageing in women.

Stress and obesity: the role of the hypothalamic-pituitary-adrenal axis in metabolic disease

PURPOSE OF REVIEW

Chronic stress, combined with positive energy balance, may be a contributor to the increased risk for obesity, especially upper body obesity, and other metabolic diseases. This association may be mediated by alterations in the hypothalamic-pituitary-adrenal (HPA) axis. In this review, we summarize the major research that has been conducted on the role of the HPA axis in obesity and metabolic disease.

RECENT FINDINGS

Dysregulation in the HPA axis has been associated with upper body obesity, but data are inconsistent, possibly due to methodological differences across studies. In addition to systemic effects, changes in local cortisol metabolism in adipose tissue may also influence the risk for obesity. HPA axis dysregulation may be the causal link between conditions such as maternal malnutrition and sleep deprivation with metabolic disease.

SUMMARY

The present review provides evidence for the relationship between chronic stress, alterations in HPA activity, and obesity. Understanding these associations and its interactions with other factors will be important in developing effective treatments for obesity and related metabolic diseases.