Effects of an 11β-hydroxysteroid dehydrogenase type 1 inhibitor, MK-0916, in patients with type 2 diabetes mellitus and metabolic syndrome

Non-alcoholic fatty liver disease in common endocrine disorders

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of disease spanning from simple benign steatosis to steatohepatitis with fibrosis and scarring that can eventually lead to cirrhosis. Its prevalence is rising rapidly and is developing into the leading indication for liver transplantation worldwide. Abnormalities in endocrine axes have been associated with NALFD, including hypogonadism, hypothyroidism, GH deficiency and hypercortisolaemia. In some instances, correction of the endocrine defects has been shown to have a beneficial impact. While in patients with type 2 diabetes the association with NAFLD is well established and recognised, there is a more limited appreciation of the condition among common endocrine diseases presenting with hormonal excess or deficiency. In this review, we examine the published data that have suggested a mechanistic link between endocrine abnormalities and NAFLD and summarise the clinical data endorsing these observations.

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.

11β-Hydroxysteroid dehydrogenase blockade prevents age-induced skin structure and function defects

Glucocorticoid (GC) excess adversely affects skin integrity, inducing thinning and impaired wound healing. Aged skin, particularly that which has been photo-exposed, shares a similar phenotype. Previously, we demonstrated age-induced expression of the GC-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in cultured human dermal fibroblasts (HDFs). Here, we determined 11β-HSD1 levels in human skin biopsies from young and older volunteers and examined the aged 11β-HSD1 KO mouse skin phenotype. 11β-HSD1 activity was elevated in aged human and mouse skin and in PE compared with donor-matched photo-protected human biopsies. Age-induced dermal atrophy with deranged collagen structural organization was prevented in 11β-HSD1 KO mice, which also exhibited increased collagen density. We found that treatment of HDFs with physiological concentrations of cortisol inhibited rate-limiting steps in collagen biosynthesis and processing. Furthermore, topical 11β-HSD1 inhibitor treatment accelerated healing of full-thickness mouse dorsal wounds, with improved healing also observed in aged 11β-HSD1 KO mice. These findings suggest that elevated 11β-HSD1 activity in aging skin leads to increased local GC generation, which may account for adverse changes occurring in the elderly, and 11β-HSD1 inhibitors may be useful in the treatment of age-associated impairments in dermal integrity and wound healing.

Evaluation of selective inhibitors of 11β-HSD1 for the treatment of hypertension

In an effort to understand the origin of blood-pressure lowering effects observed in recent clinical trials with 11β-HSD1 inhibitors, we examined a set of 11β-HSD1 inhibitors in a series of relevant in vitro and in vivo assays. Select 11β-HSD1 inhibitors reduced blood pressure in our preclinical models but most or all of the blood pressure lowering may be mediated by a 11β-HSD1 independent pathway.

Chronic inhibition of 11 β -hydroxysteroid dehydrogenase type 1 activity decreases hypertension, insulin resistance, and hypertriglyceridemia in metabolic syndrome

Metabolic syndrome is a constellation of risk factors including hypertension, dyslipidemia, insulin resistance, and obesity that promote the development of cardiovascular disease. Metabolic syndrome has been associated with changes in the secretion or metabolism of glucocorticoids, which have important functions in adipose, liver, kidney, and vasculature. Tissue concentrations of the active glucocorticoid cortisol are controlled by the conversion of cortisone to cortisol by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Because of the various cardiovascular and metabolic activities of glucocorticoids, we tested the hypothesis that 11β-HSD1 is a common mechanism in the hypertension, dyslipidemia, and insulin resistance in metabolic syndrome. In obese and lean SHR/NDmcr-cp (SHR-cp), cardiovascular, metabolic, and renal functions were measured before and during four weeks of administration of vehicle or compound 11 (10 mg/kg/d), a selective inhibitor of 11β-HSD1. Compound 11 significantly decreased 11β-HSD1 activity in adipose tissue and liver of SHR-cp. In obese SHR-cp, compound 11 significantly decreased mean arterial pressure, glucose intolerance, insulin resistance, hypertriglyceridemia, and plasma renin activity with no effect on heart rate, body weight gain, or microalbuminuria. These results suggest that 11β-HSD1 activity in liver and adipose tissue is a common mediator of hypertension, hypertriglyceridemia, glucose intolerance, and insulin resistance in metabolic syndrome.

[Importance of the 11β-hydroxysteroid dehydrogenase enzyme in clinical disorders]

Glucocorticoids play an important role in the regulation of carbohydrate and amino acid metabolism, they modulate the function of the immune system, and contribute to stress response. Increased and decreased production of glucocorticoids causes specific diseases. In addition to systemic hypo- or hypercortisolism, alteration of local synthesis and metabolism of cortisol may result in tissue-specific hypo- or hypercortisolism. One of the key enzymes participating in the local synthesis and metabolism of cortisol is the 11β-hydroxysteroid dehydrogenase enzyme. Two isoforms, type 1 and type 2 enzymes are located in the endoplasmic reticulum and catalyze the interconversion of hormonally active cortisol and inactive cortisone. The type 1 enzyme mainly works as an activator, and it is responsible for the generation of cortisol from cortisone in liver, adipose tissue, brain and bone. The gene encoding this enzyme is located on chromosome 1. The authors review the physiological and pathophysiological processes related to the function of the type 1 11β-hydroxysteroid dehydrogenase enzyme. They summarize the potential significance of polymorphic variants of the enzyme in clinical diseases as well as knowledge related to inhibitors of enzyme activity. Although further studies are still needed, inhibition of the enzyme activity may prove to be an effective tool for the treatment of several diseases such as obesity, osteoporosis and type 2 diabetes.

Clinical Safety, Pharmacokinetics, and Pharmacodynamics of the 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitor ABT-384 in Healthy Volunteers and Elderly Adults

ABT-384 is a potent and selective inhibitor of 11β-hydroxysteroid dehydrogenase type 1 (HSD-1), the enzyme that regenerates cortisol in several tissues. Two clinical studies of ABT-384 were undertaken to assess its safety, pharmacokinetics, target engagement, and pharmacologic effects in healthy subjects. Single doses from 1 to 240 mg, and multiple doses from 1 to 100 mg once daily for 7-14 days, were administered to healthy adults. Multiple doses from 10 to 100 mg once daily for 21 days were administered to elderly subjects. A total of 103 subjects received at least 1 dose of ABT-384. A maximum-tolerated dose was not defined in either study. The pharmacokinetic profiles of ABT-384 and its active metabolite support once daily dosing. Analysis of urine cortisol metabolites demonstrated full hepatic HSD-1 inhibition with regimens from 1 mg daily, and confirmed in vitro target selectivity. Pharmacologic effects included increases of adrenocorticotrophic hormone levels, cortisol production and androgen and estradiol levels. ABT-384 has a wide therapeutic index relative to full hepatic target engagement which is relevant for indications such as diabetes and metabolic syndrome. Its therapeutic index for other potential indications such as Alzheimer's disease remains to be established.

Effect of ketoconazole on the pharmacokinetics of the 11β-hydroxysteroid dehydrogenase type 1 inhibitor ABT-384 and its two active metabolites in healthy volunteers: population analysis of data from a drug-drug interaction study

ABT-384 [1-piperazineacetamide, N-[5-(aminocarbonyl) tricyclo[3.3.1.13,7]dec-2-yl]-α,α-dimethyl-4-[5-(trifluoromethyl)-2-pyridinyl]-,stereoisomer] is a potent and selective inhibitor of 11β-hydroxysteroid dehydrogenase type 1 (HSD-1). ABT-384 has been shown to be safe and well tolerated in humans at doses up to 100 mg daily, and to fully inhibit both peripheral and brain HSD-1 at a dose of 2 mg daily. The effect of ketoconazole on the pharmacokinetics of ABT-384 and its two active metabolites, A-1331480 and A-847082, was investigated in healthy volunteers. When 10 mg of ABT-384 was coadministered with ketoconazole, ABT-384 exposures increased 18-fold for area under the plasma concentration-time curve from time 0 to infinity and 3.5-fold for Cmax. The results suggest that ABT-384 is a sensitive substrate of CYP3A. After ketoconazole coadministration, exposures of A-1331480 and A-847082 were also greatly increased. A population pharmacokinetic model was constructed for ABT-384 and its metabolites using NonMEM. A two-compartment model with three transit absorption compartments best described ABT-384 data. The model predicted a 69.3% decrease in ABT-384 clearance and 91.1% increase in the volume of distribution of ABT-384 in the presence of ketoconazole. A-1331480 was shown to be formation rate-limited and A-847082 was elimination rate-limited. Both metabolites were characterized by a one-compartment model with first-order rate constants of formation and elimination. Overall the model adequately captured the concentration-time profiles of ABT-384, A-1331480, and A-847082 in both ABT-384-alone and ketoconazole-coadministration conditions. Although ABT-384 exposures were greatly increased in the presence of ketoconazole, coadministration of ABT-384 with ketoconazole or other strong/moderate CYP3A inhibitors is not expected to contribute to any major clinical safety issues considering the favorable safety profile of ABT-384.

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.

Glucocorticoids and type 2 diabetes: from physiology to pathology

Type 2 diabetes mellitus is the result of interaction between genetic and environmental factors, leading to heterogeneous and progressive pancreatic β-cell dysfunction. Overweight and obesity are major contributors to the development of insulin resistance and impaired glucose tolerance. The inability of β cells to secrete enough insulin produces type 2 diabetes. Abnormalities in other hormones such as reduced secretion of the incretin glucagon-like peptide 1 (GLP-1), hyperglucagonemia, and raised concentrations of other counterregulatory hormones also contribute to insulin resistance, reduced insulin secretion, and hyperglycaemia in type 2 diabetes. Clinical-overt and experimental cortisol excess is associated with profound metabolic disturbances of intermediate metabolism resulting in abdominal obesity, insulin resistance, and low HDL-cholesterol levels, which can lead to diabetes. It was therefore suggested that subtle abnormalities in cortisol secretion and action are one of the missing links between insulin resistance and other features of the metabolic syndrome. The aim of this paper is to address the role of glucocorticoids on glucose homeostasis and to explain the relationship between hypercortisolism and type 2 diabetes.

Contribution of endogenous glucocorticoids and their intravascular metabolism by 11β-HSDs to postangioplasty neointimal proliferation in mice

Exogenous glucocorticoids inhibit neointimal proliferation in animals. We aimed to test the hypothesis that endogenous glucocorticoids influence neointimal proliferation; this may be mediated by effects on systemic risk factors or locally in vessels and modulated by either adrenal secretion or enzymes expressed in vessels that mediate local inactivation [11β-hydroxysteroid dehydrogenase type II (11β-HSD2) in endothelium] or regeneration [11β-hydroxysteroid dehydrogenase type I (11β-HSD1) in smooth muscle] of glucocorticoids. Femoral artery wire angioplasty was conducted in C57BL/6J, Apo-E(-/-), 11β-HSD1(-/-), Apo-E, 11β-HSD1(-/-) (double knockout), and 11β-HSD2(-/-) mice after glucocorticoid administration, adrenalectomy, glucocorticoid or mineralocorticoid receptor antagonism, or selective 11β-HSD1 inhibition. In C57BL/6J mice, neointimal proliferation was reduced by systemic or local glucocorticoid administration, unaffected by adrenalectomy, reduced by the mineralocorticoid receptor antagonist eplerenone, and increased by the glucocorticoid receptor antagonist RU38486. 11β-HSD2 deletion had no effect on neointimal proliferation, with or without eplerenone. 11β-HSD1 inhibition or deletion had no effect in chow-fed C57BL/6J mice but reduced neointimal proliferation in Apo-E(-/-) mice on Western diet. Reductions in neointimal size were accompanied by reduced macrophage and increased collagen content. We conclude that pharmacological administration of glucocorticoid receptor agonists or of mineralocorticoid receptor antagonists may be useful in reducing neointimal proliferation. Endogenous corticosteroids induce beneficial glucocorticoid receptor activation and adverse mineralocorticoid receptor activation. However, manipulation of glucocorticoid metabolism has beneficial effects only in mice with exaggerated systemic risk factors, suggesting effects mediated primarily in liver and adipose rather than intravascular glucocorticoid signaling. Reducing glucocorticoid action with 11β-HSD1 inhibitors that are being developed for type 2 diabetes appears not to risk enhanced neointimal proliferation.

Discovery of 2-Alkyl-1-arylsulfonylprolinamides as 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitors

On the basis of scaffold hopping, a novel series of 2-alkyl-1-arylsulfonylprolinamides was discovered as 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD-1) inhibitors. A representative compound 4ek, obtained through SAR and structure optimization studies, demonstrates excellent in vitro potency against 11β-HSD-1 and dose-dependent in vivo inhibition of 11β-HSD-1 in a prednisone/prednisolone transformation biomarker study in mice.

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.

Is there sufficient evidence to consider the use of 11β-hydroxysteroid dehydrogenase type 1 inhibition in children?

Manifestations of the metabolic syndrome [obesity, dyslipidaemia, hypertension, blood glucose derangements including prediabetes or type 2 diabetes mellitus (T2DM)] in juvenile populations are becoming increasingly prevalent throughout the world and are at the point of being a global public health concern. Derangements in cortisol regeneration seem to be involved in the pathophysiology. Treatment with selective 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) inhibitors could be a therapeutic strategy in paediatric patients with manifestations of the metabolic syndrome. Based on preclinical and clinical data regarding development of the 11β-HSD1 enzyme, it appears that maturation occurs within the first year of life. Different changes in biomarkers for assessing the efficacy and safety of 11β-HSD1 inhibitors are to be expected in paediatric patients compared to adults, reflecting differences in metabolism. The effect of 11β-HSD1 treatment in children on bone differentiation and development as well as adrenocorticotropic hormone (ACTH), circulating and local cortisol tissue concentrations, androgens and respective stress response is not yet known. Based on current literature, the concept of inhibition of 11β-HSD1 is considered a potentially effective mean to regulate local cortisol levels in the paediatric population, and 11β-HSD1 inhibitors may provide a valuable target and treatment option for the metabolic syndrome in paediatric patients. However, the uncertainty over effects on the developing skeleton combined with mild increases in adrenal androgen levels raises potential concerns regarding growth as well as onset of puberty as to their future use in children. Future clinical studies are needed to thoroughly assess the risks and benefits of this new class of drugs in the paediatric population.

CIDeR: multifactorial interaction networks in human diseases

The pathobiology of common diseases is influenced by heterogeneous factors interacting in complex networks. CIDeR http://mips.helmholtz-muenchen.de/cider/ is a publicly available, manually curated, integrative database of metabolic and neurological disorders. The resource provides structured information on 18,813 experimentally validated interactions between molecules, bioprocesses and environmental factors extracted from the scientific literature. Systematic annotation and interactive graphical representation of disease networks make CIDeR a versatile knowledge base for biologists, analysis of large-scale data and systems biology approaches.

Discovery of a potent, selective, and orally bioavailable acidic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor: discovery of 2-[(3S)-1-[5-(cyclohexylcarbamoyl)-6-propylsulfanylpyridin-2-yl]-3-piperidyl]acetic acid (AZD4017)

Inhibition of 11β-HSD1 is an attractive mechanism for the treatment of obesity and other elements of the metabolic syndrome. We report here the discovery of a nicotinic amide derived carboxylic acid class of inhibitors that has good potency, selectivity, and pharmacokinetic characteristics. Compound 11i (AZD4017) is an effective inhibitor of 11β-HSD1 in human adipocytes and exhibits good druglike properties and as a consequence was selected for clinical development.

Recycling between cortisol and cortisone in human splanchnic, subcutaneous adipose, and skeletal muscle tissues in vivo

11β-Hydroxysteroid dehydrogenase type 1 (11βHSD1) is a therapeutic target in metabolic syndrome because it catalyses reductase regeneration of cortisol from cortisone in adipose and liver. 11βHSD1 can also catalyze the reverse dehydrogenase reaction in vitro (e.g., if cofactor is limited). We used stable isotope tracers to test the hypothesis that both 11βHSD1-reductase and -dehydrogenase activities occur in human metabolic tissues in vivo. 1,2-[(2)H](2)-Cortisone (d2-cortisone) was validated as a tracer for 11β-dehydrogenase activity and its inhibition by licorice. d2-Cortisone and 9,11,12,12-[(2)H](4)-cortisol (d4-cortisol) (to measure 11β-reductase activity) were coinfused and venous samples obtained from skeletal muscle, subcutaneous adipose (n = 6), and liver (n = 4). Steroids were measured by liquid chromatography-tandem mass spectrometry and arteriovenous differences adjusted for blood flow. Data are means ± SEM. 11β-Reductase and -dehydrogenase activities were detected in muscle (cortisol release 19.7 ± 4.1 pmol/100 mL/min, d3-cortisol 5.9 ± 1.8 pmol/100 mL/min, and cortisone 15.2 ± 5.8 pmol/100 mL/min) and splanchnic (cortisol 64.0 ± 11.4 nmol/min, d3-cortisol 12.9 ± 2.1 nmol/min, and cortisone 19.5 ± 2.8 nmol/min) circulations. In adipose, dehydrogenase was more readily detected than reductase (cortisone release 38.7 ± 5.8 pmol/100 g/min). Active recycling between cortisol and cortisone in metabolic tissues in vivo may facilitate dynamic control of intracellular cortisol but makes consequences of dysregulation of 11βHSD1 transcription in obesity and diabetes unpredictable. Disappointing efficacy of 11βHSD1 inhibitors in phase II studies could be explained by lack of selectivity for 11β-reductase.

Antisense reduction of 11β-hydroxysteroid dehydrogenase type 1 enhances energy expenditure and insulin sensitivity independent of food intake in C57BL/6J mice on a Western-type diet

We recently reported that inhibition of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) by antisense oligonucleotide (ASO) improved hepatic lipid metabolism independent of food intake. In that study, 11β-HSD1 ASO-treated mice lost weight compared with food-matched control ASO-treated mice, suggesting treatment-mediated increased energy expenditure. We have now examined the effects of 11β-HSD1 ASO treatment on adipose tissue metabolism, insulin sensitivity, and whole-body energy expenditure. We used an ASO to knock down 11β-HSD1 in C57BL/6J mice consuming a Western-type diet (WTD). The 11β-HSD1 ASO-treated mice consumed less food, so food-matched control ASO-treated mice were also evaluated. We characterized body composition, gene expression of individual adipose depots, and measures of energy metabolism. We also investigated glucose/insulin tolerance as well as acute insulin signaling in several tissues. Knockdown of 11β-HSD1 protected against WTD-induced obesity by reducing epididymal, mesenteric, and subcutaneous white adipose tissue while activating thermogenesis in brown adipose tissue. The latter was confirmed by demonstrating increased energy expenditure in 11β-HSD1 ASO-treated mice. The 11β-HSD1 ASO treatment also protected against WTD-induced glucose intolerance and insulin resistance; this protection was associated with smaller cells and fewer macrophages in epididymal white adipose tissue as well as enhanced in vivo insulin signaling. Our results indicate that ASO-mediated inhibition of 11β-HSD1 can protect against several WTD-induced metabolic abnormalities. These effects are, at least in part, mediated by increases in the oxidative capacity of brown adipose tissue.

Salicylate downregulates 11β-HSD1 expression in adipose tissue in obese mice and in humans, mediating insulin sensitization

Recent trials show salicylates improve glycemic control in type 2 diabetes, but the mechanism is poorly understood. Expression of the glucocorticoid-generating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in adipose tissue is increased in vitro by proinflammatory cytokines and upregulated in obesity. 11β-HSD1 inhibition enhances insulin sensitivity. We hypothesized that salicylates downregulate 11β-HSD1 expression, contributing to their metabolic efficacy. We treated diet-induced obese (DIO) 11β-HSD1-deficient mice and C57Bl/6 mice with sodium salicylate for 4 weeks. Glucose tolerance was assessed in vivo. Tissue transcript levels were assessed by quantitative PCR and enzyme activity by incubation with (3)H-steroid. Two weeks' administration of salsalate was also investigated in a randomized double-blind placebo-controlled crossover study in 16 men, with measurement of liver 11β-HSD1 activity in vivo and adipose tissue 11β-HSD1 transcript levels ex vivo. In C57Bl/6 DIO mice, salicylate improved glucose tolerance and downregulated 11β-HSD1 mRNA and activity selectively in visceral adipose. DIO 11β-HSD1-deficient mice were resistant to these metabolic effects of salicylate. In men, salsalate reduced 11β-HSD1 expression in subcutaneous adipose, and in vitro salicylate treatment reduced adipocyte 11β-HSD1 expression and induced adiponectin expression only in the presence of 11β-HSD1 substrate. Reduced intra-adipose glucocorticoid regeneration by 11β-HSD1 is a novel mechanism that contributes to the metabolic efficacy of salicylates.

Overexpression of hepatic 5α-reductase and 11β-hydroxysteroid dehydrogenase type 1 in visceral adipose tissue is associated with hyperinsulinemia in morbidly obese patients

11-β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts cortisone to cortisol, mainly in the liver and visceral adipose tissue (VAT), and has been implicated in several metabolic disorders. The absence of systemic hypercortisolism in central obesity could be due to increased inactivation of cortisol to its tetrahydrometabolites by the hepatic enzymes 5α- and 5β-reductases. Our aim was to assess the expression of the reductases in the liver and of 11β-HSD1 in the liver and VAT in morbidly obese patients and to analyze their association with clinical, anthropometric, and biochemical parameters. Hepatic and VAT samples were obtained during bariatric surgery. 5α- and 5β-reductases, 11β-HSD1, and 18S expression was measured using real-time polymerase chain reaction. Anthropometric and biochemical variables were analyzed. Forty-one patients were recruited (age, 41.8 ± 10.6 years; body mass index, 42.1 ± 6.6 kg/m(2); 71% women). The expression of hepatic 5α- and 5β-reductases was positively correlated (r = +0.53, P = .004), and their expression levels were correlated with hepatic 11β-HSD1 expression (r = +0.61, P < .001 for 5α-reductase and r = +0.50, P < .001 for 5β-reductase). Hepatic 5α-reductase was associated with insulin (r = +0.34, P = .015). Visceral adipose tissue 11β-HSD1 expression was associated with glucose (r = +0.37, P = .025) and insulin (r = +0.54, P = .002). Our results showed that 5α-reductase and VAT 11β-HSD1 expressions were associated with insulinemia. These findings suggest that overexpression of 5α-reductase, through a higher inactivation of cortisol in the liver, could have a protective role in preserving hepatic sensitivity to insulin. The overexpression of liver reductases in obesity could be an adaptive response to an increase in cortisol production by the liver and visceral 11β-HSD1 to avoid systemic hypercortisolism.