Alterations in glucocorticoid homeostasis following sleeve gastrectomy in male mice.

Elevated intra-tissue levels of active glucocorticoids in obese patients are associated with insulin resistance, diabetes, impaired immune regulation, and other adverse effects. Sleeve gastrectomy (SG) induces significant weight loss and improves metabolic outcomes, including insulin resistance and hyperlipidemia. Among the enzymes controlling intracellular concentrations of active glucocorticoids, 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1, SDR26C1) has been extensively studied concerning obesity and post-gastric surgery interventions. However, most studies focused on either a single tissue, circulating glucocorticoid levels, or HSD11B1 activity. In this work, we showed that circulating active/inactive glucocorticoid ratio (corticosterone (B)/11-dehydrocorticosterone (A)) negatively correlated with glucose tolerance; SG in male C57BL/6 mice slightly reduced circulating mineralocorticoids and reversed the elevated ratio of B/A seen in sham-operated mice after high-fat diet, while improving glucose tolerance. This change was likely due to increased renal 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2, SDR9C3) activity after SG. To provide a comprehensive overview of the systemic effects post-surgery, we evaluated enzymes involved in glucocorticoid homeostasis across tissues on mRNA, protein, and activity level. Moreover, mRNA expression of transcription factors CCAAT enhancer binding protein alpha (Cebpa), Cebpb and nuclear factor kappa b (Nfκb (p50)), as well as cytokines influencing Hsd11b1 and Hsd11b2 gene expression were analyzed. The results emphasize stronger influence of renal HSD11B2 than hepatic HSD11B1 activity on the circulating B/A ratio, supported by intrarenal and intrahepatic B/A ratios. The improved glucocorticoid homeostasis following SG, indicated by decreased B/A ratios, proposes a lower risk for glucocorticoid-mediated adverse health effects, including chronic kidney disease, hypertension, and metabolic disturbances.

11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) converts inactive 11-keto derivatives to active glucocorticoids within tissues and may play a role in the metabolic syndrome (MS). We used an antisense oligonucleotide (ASO) to knock down 11β-HSD1 in livers of C57BL/6J mice consuming a Western-type diet (WTD). 11β-HSD1 ASO-treated mice consumed less food, so we compared them to ad libitum-fed mice and to food-matched mice receiving control ASO. Knockdown of 11β-HSD1 directly protected mice from WTD-induced steatosis and dyslipidemia by reducing synthesis and secretion of triglyceride (TG) and increasing hepatic fatty acid oxidation. These changes in hepatic and plasma lipids were not associated with reductions in genes involved in de novo lipogenesis. However, protein levels of both sterol regulatory element-binding protein (SREBP) 1 and fatty acid synthase were significantly reduced in mice treated with 11β-HSD1 ASO. There was no change in hepatic secretion of apolipoprotein (apo)B, indicating assembly and secretion of smaller apoB-containing lipoproteins by the liver in the 11β-HSD1-treated mice. Our results indicate that inhibition of 11β-HSD1 by ASO treatment of WTD-fed mice resulted in improved plasma and hepatic lipid levels, reduced lipogenesis by posttranslational regulation, and secretion of similar numbers of apoB-containing lipoproteins containing less TG per particle.

Weight regain and type-2 diabetes relapse has been reported in a significant proportion of vertical sleeve gastrectomy (VSG) patients in some studies, but definitive conclusions regarding the long-term comparative effectiveness of VSG and Roux-en-Y gastric bypass (RYGB) surgery are lacking both in humans and rodent models. This study's objective was to compare the effects of murine models of VSG and RYGB surgery on body weight, body composition, food intake, energy expenditure, and glycemic control. VSG, RYGB, and sham surgery was performed in high-fat diet-induced obese mice, and the effects on body weight and glycemic control were observed for a period of 12weeks. After the initial weight loss, VSG mice regained significant amounts of body weight and fat mass that were only marginally lower than in sham-operated mice. In contrast, RYGB produced sustained loss of body weight and fat mass up to 12weeks and drastically improved fasting insulin and HOMA-IR compared with sham-operated mice. Using weight-matched control groups, we also found that the adaptive hypometabolic response to weight loss was blunted by both VSG and RYGB, and that despite large weight/fat regain, fasting insulin and HOMA-IR were markedly improved, but not reversed, in VSG mice. VSG is less effective to lastingly suppress body weight and improve glycemic control compared with RYGB in mice. Given similar observations in many human studies, the run towards replacing RYGB with VSG is premature and should await carefully controlled randomized long-term trials with VSG and RYGB.

1952-P: Vertical Sleeve Gastrectomy Induces Distinctive Gene Expression Changes in Glucose-Utilizing Peripheral Organs

Recent findings indicate that elevated levels of glucocorticoids (GC), governed by the expression of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) and GC receptors (GR), in visceral adipose tissue and skeletal muscle lead to increased insulin resistance and the metabolic syndrome. Paradoxically, evidence indicates that aerobic exercise attenuates the development of the metabolic syndrome even though it stimulates acute increases in circulating GC levels. To investigate the hypothesis that training alters peripheral GC action to maintain insulin sensitivity, young male hamsters were randomly divided into sedentary (S) and trained (T) groups (n = 8 in each). The T group had 24-h access to running wheels over 4 wk of study. In muscle, T hamsters had lower 11beta-HSD1 protein expression (19.2 +/- 1.40 vs. 22.2 +/- 0.96 optical density, P < 0.05), similar 11beta-HSD1 enzyme activity (0.9 +/- 0.27% vs. 1.1 +/- 0.26), and lower GR protein expression (9.7 +/- 1.86 vs. 15.1 +/- 1.78 optical density, P < 0.01) than S hamsters. In liver, 11beta-HSD1 protein expression tended to be lower in T compared with S (19.2 +/- 0.56 vs. 21.4 +/- 1.05, P = 0.07), whereas both enzyme activity and GR protein expression were similar. In contrast, visceral adipose tissue contained approximately 2.7-fold higher 11beta-HSD1 enzyme activity in T compared with S (12.9 +/- 3.3 vs. 4.8 +/- 1.5% conversion, P < 0.05) but was considerably smaller in mass (0.24 +/- 0.02 vs. 0.71 +/- 0.06 g). Thus the intracellular adaptation of GC regulators to exercise is tissue specific, resulting in decreases in GC action in skeletal muscle and increases in GC action in visceral fat. These adaptations may have important implications in explaining the protective effects of aerobic exercise on insulin resistance and other symptoms of the metabolic syndrome.

PVAT is a critical regulator of vascular contractility and its dysfunction contributes to obesity-induced hypertension (HTN). Bariatric surgery, such as vertical sleeve gastrectomy (VSG), causes high rates of HTN remission prior to weight loss, and rescues PVAT function by increasing nitric oxide (NO) production. We have previously validated a VSG mouse model that recapitulates the body weight-independent lowering of blood pressure. VSG increases bile acid (BA) signaling through the BA receptor, TGR5. TGR5 stimulates NO production from endothelial cells (ECs) but the role of TGR5 signaling in adipocyte NO production is unknown. We hypothesized that VSG increases NO bioavailability within PVAT in a TGR5-dependent manner. High fat diet (HFD)-fed male C57BLmice underwent VSG or sham surgery ( n =4-6) Sham (S) mice were food restricted to match body weight to VSG mice. Vascular contractility was reduced in VSG mice (Max contraction (%): S: 30±2, VSG: 23±3; P &lt;0.05). To assess the role of TGR5 on NO production within PVAT, we performed western blotting on mesenteric PVAT from VSG or sham-operated HFD-fed TGR5 WT and KO mice. eNOS phosphorylation was increased in PVAT in VSG WT, but not VSG KO (western blot quantification (AU): S WT: 1.0±0.1, VSG WT: 1.3±0.1, S KO: 1.1±0, VSG KO: 1.0±0.1; P &lt;0.05). To determine how TGR5 regulates PVAT NO production, we assessed the impact of TGR5 on microRNA-21 (miR-21) expression. MiR-21 stimulates NO production in ECs but its role in adipocytes in unknown. Thus, we hypothesized that TGR5 regulates NO production within PVAT by upregulating miR-21. MiR-21 expression was increased in PVAT from VSG-operated TGR5 WT mice but not KO compared to sham controls (western blot quantification (AU): S WT: 0.9±0.1, VSG WT: 2.1±0.5, S KO: 0.7±0.6, VSG KO: 0.6±0.1; P &lt;0.05). We further investigated whether TGR5 activation and miR-21 overexpression stimulate NO production in adipocytes. Mature 3T3-L1 adipocytes were treated with INT-777 or transfected with miR-21 mimic. TGR5 activation and miR-21 overexpression increased eNOS phosphorylation ( P &lt;0.05). In conclusion, our data suggest that VSG increases NO bioavailability in PVAT by activating adipocyte TGR5 signaling and upregulating miR-21 expression.

Vertical sleeve gastrectomy (VSG) is the most commonly performed bariatric/metabolic surgery, exhibiting a high rate of diabetes remission in humans. To elucidate the molecular mechanisms of VSG, we performed transcriptomic analysis of the liver, fat, and muscle in VSG mice. C57BL/6 mice fed a high-fat diet were randomly assigned to sham or VSG surgery. The sham-operated mice were fed ad libitum (sham group) or pair-fed (sham-PF group) matching their food intake to the VSG-operated mice. Comparative transcriptomic analysis of the liver, fat, and muscle using RNA sequencing was performed. VSG reduced body weight and improved glucose tolerance compared to the sham group, but not more than the sham-PF group. Improvement in fatty liver and adipose tissue inflammation was comparable between VSG and sham-PF. However, global gene expression profiles showed distinctive changes in the liver, fat, and muscle of the VSG group compared to both the sham or sham-PF groups. The liver showed the most prominent gene expression changes. Immune response-related pathways were commonly upregulated in the three organs of the VSG group compared to the sham or sham-PF. VSG induces organ-specific gene expression changes in the liver, fat, and muscle, which may play critical roles in metabolic improvements after VSG.

A rodent model of partial intestinal diversion: a novel metabolic operation.

High Iron Feeding Modulates Glucose Metabolism in Duodenal-Jejunal Bypass Surgery but Not in Vertical Sleeve Gastrectomy in Mice

BackgroundStudies have shown that bariatric surgery, such as sleeve gastrectomy (SG), has an adverse effect on bone, including decreased bone mineral density (BMD) and bone metabolism. Peripheral 5-hydroxytryptamine (5-HT) has an adverse regulatory effect on bone formation. Here, we assessed changes in bone metabolism and whether 5-HT is involved in the effect of SG on bone metabolism.Material/MethodsA rat model of obesity was established using Wistar rats. After successful modeling, rats were randomly assigned to 2 groups – the SG group and the Sham group – with 10 rats in each group. We then performed sleeve gastrectomy or sham operation. Bone metabolic markers and BMD of rats were measured at 2 and 16 weeks after the operation and the level of 5-HT in serum was determined. Rats were killed at 16 weeks after the operation, and bones of the hind limbs were harvested to measure 5-HT by immunofluorescence.ResultsBMD was decreased and bone metabolism demonstrated a trend of bone destruction in the rats after SG. A significantly increasing trend in the level of serum 5-HT was found, and bone immunofluorescence showed increased expression of 5-HT.ConclusionsBMD was decrease and bone metabolism demonstrated a trend of bone destruction after SG. SG can affect the level of 5-HT in serum or bone tissue and the 5-HT may be involved in the process through which SG affects bone metabolism.

ObjectivesGlucocorticoids produced by the adrenal cortex are essential for the maintenance of metabolic homeostasis. Glucocorticoid activation is catalysed by 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). Excess glucocorticoids are associated with insulin resistance and hyperglycaemia. A small number of studies have demonstrated effects on glucocorticoid metabolism of bariatric surgery, a group of gastrointestinal procedures known to improve insulin sensitivity and secretion, which were assumed to result from weight loss. In this study, we hypothesize that a reduction in glucocorticoid action following bariatric surgery contributes to the widely observed euglycemic effects of the treatment.MethodsGlucose and insulin tolerance tests were performed at ten weeks post operatively and circulating corticosterone was measured. Liver and adipose tissues were harvested from fed mice and 11β-HSD1 levels were measured by quantitative RT-PCR or Western (immuno-) blotting, respectively. 11β-HSD1 null mice (Hsd11b1 -/-) were generated using CRISPR/Cas9 genome editing. Wild type and littermate Hsd11b1 -/- mice underwent Vertical Sleeve Gastrectomy (VSG) or sham surgery. ResultsUnder the conditions used, no differences in weight loss were observed between VSG treated and sham operated mice. However, both lean and obese WT VSG mice displayed significantly improved glucose clearance and insulin sensitivity. Remarkably, VSG restored physiological corticosterone production in HFD mice and reduced 11β-HSD1 expression in liver and adipose tissue post-surgery. Elimination of the 11β-HSD1/Hsd11b1 gene by CRISPR/Cas9 mimicked the effects of VSG on body weight and tolerance to 1g/kg glucose challenge. However, at higher glucose loads, the euglycemic effect of VSG was superior to Hsd11b1 elimination.ConclusionsBariatric surgery improves insulin sensitivity and reduces glucocorticoid activation at the tissular level, under physiological and pathophysiological (obesity) conditions, irrespective of weight loss. These findings point towards a physiologically relevant gut-glucocorticoid axis, and suggest that lowered glucocorticoid exposure may represent an additional contribution to the health benefits of bariatric surgery.

11β-Hydroxysteroid dehydrogenase type 2 in pregnancy and preeclampsia

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.

To investigate the association between 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity and antiretroviral therapy (ART)-induced increase in low-density lipoprotein cholesterol (LDL). We enrolled 62 patients and used liquid chromatography-tandem mass spectrometry to measure 11β-HSD1 activity, which was expressed as a ratio of the sum of urinary tetrahydrocortisol and allo-tetrahydrocortisol concentrations to urinary tetrahydrocortisone concentration. Patient data, including baseline laboratory values, were extracted from medical records for logistic regression analyses of factors associated with LDL increase during ART. The cutoff 11β-HSD1 activity ratio associated with the LDL increase during ART was determined using receiver operator characteristic (ROC) curve analysis. The LDL level increased significantly from 88.8mg/dL before ART to 106.7mg/dL during ART (p=0.04). Additionally, patients with increased LDL tended to have a higher 11β-HSD1 activity ratio (1.59 vs. 1.21, p=0.06) and longer duration of ART (13.9 vs. 10.2 months, p=0.07) than patients with unchanged or decreased LDL. The cutoff 11β-HSD1 activity ratio was 1.226. Results of the univariate logistic regression analysis suggested that 11β-HSD1 activity ratio ≥1.226 was associated with LDL increase during ART (p=0.011), with an odds ratio of 8.000. This study revealed the possible association between 11β-HSD1 activity and ART-induced LDL increase. The findings of this study suggest that 11β-HSD1 could be a useful drug target for the treatment of ART-induced hyperlipidemia.

Impairment in 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) activity results in inefficient inactivation of cortisol to cortisone, and it can trigger hypertension through activation of the mineralocorticoid receptor. Information about age-related changes in 11β-HSD2 activity and its physiological consequences is scarce. Our aim was to investigate whether 11β-HSD2 activity is age dependent in normotensive subjects. We recruited 196 healthy, normotensive subjects. Of these, 93 were children (Group 1: aged 5-15 years), and 103 were adults who were divided according to their ages: Group 2: aged 30-41 years (n = 10); Group 3: aged 42-53 years (n = 72); and Group 4: aged 54-65 years (n = 21). Fasting serum cortisol, cortisone, aldosterone, and plasma renin activity (PRA) were measured. The 11β-HSD2 activity was estimated by the cortisol/cortisone ratio. The results were expressed as median (interquartile range (IQR)) values and compared using Kruskal-Wallis and Dunn's multiple-comparison tests. As subject age increased, cortisol concentrations increased (Group 1 median = 8.6, IQR = 6.3-10.8 µg/dl; Group 4 median = 12.4, IQR = 10.7-14.7 µg/dl; P < 0.001), and cortisone concentrations showed a gradual decrease (Group 2 median = 4.0, IQR = 3.3-4.2 µg/dl; Group 4 median =2.8, IQR = 2.6-3.3 µg/dl; P < 0.01). As a consequence, the cortisol/cortisone ratio was higher in the oldest subjects (Group 4) than in the subjects from the other 3 groups; the ratios from Group 4 to Group 1 were 4.4 (IQR = 3.7-5.1) µg/dl, 3.3 (IQR = 2.7-3.8) µg/dl, 2.5 (IQR = 2.3-3.8) µg/dl, and 2.7 (IQR = 2.1-3.4) µg/dl, respectively (P < 0.01). The PRA decreased with age. Blood pressure levels increased with age but stayed within the normal range. Cortisol and the cortisol/cortisone ratio increased with age, but cortisone decreased, suggesting a decrease in 11β-HSD2 activity. These results suggest that the cortisol-mediated activation of the mineralocorticoid receptor may explain the blood pressure increase in elderly subjects.