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.

Regiones polimórficas del gen 11ß-hidroxiesteroide deshidrogenasa tipo 1 (11ßHSD1) en hipertensión arterial esencial: Posible rol etiopatogénico / Possible pathogenetic role of 11ß-hydroxysteroid dehydrogenase type 1 (11ßHSD1) gene polymorphisms in arterial hypertension

Background: Cortisol has been implicated in hypertension and lately reported to be regulated at the pre-receptor level by the 11ßHSD1 enzyme, which converts cortisone (E) to cortisol (F). Over expression ofthis enzyme in adipose tissue could determine an increase in available cortisol that interacts with the mineralocorticoid receptor (MR) in renal, brain and heart tissue, leading to similar hypertensive effects as in 11ßHSD2 impaired patients. Severa! polymorphisms have been reported in HSDl IB 1 gene (CAI5, CAI9 and InsA83557), which could modify HSDl IB 1 gene expression or activity. Aun: To determine the distribution and prevalence of CAI5, CAI9 and InsA83557 in the HSDl IBl gene, and to correlate these results with biochemical parameters in cortisol/ ACTH (HPA) and renin-angiotensin-aldosterone (RAA) axis in patients with essential hypertension (EH). Patients and Methods: We studied 113 EHpatients (76 non-obese and 37 obese, with a body mass índex >30 kg/m²) and 30 normotensive adults (NT). In each patient, we measured serum levéis of E E, serum aldosterone (SA), plasma renin activity (PRA), adrenocorticotrophic hormone (ACTH), the urinary free cortisol/creatinine (UFF/Cr), F/ACTH and SA/PRA ratios. Each polymorphism was studied by PCR and 8 percent polyacrylamide gel electrophoresis. Statistical associations were evaluated by Pearson correlations and the genetic equilibñum by the Hardy-Weinberg (H-W) equation. Results: We found all three polymorphisms in the EH and the NT group, both in genetic equilibñum. In obese essential hypertensives, the CAI5polymorphism showed association with SA/PRA ratio (r =0.189, p =0.012) and F/ACTH (r =0.301, p 0.048); CA19 also showed correlation with F/ACTH in obese EH (r = 0.220, p 0.009). The InsA83557polymorphism correlated with UFF/Cr in both EH (r =0.206; p =0.03), and in obese EH (r =0.354; p =0.05). Conclusions: The CAI5 and CAI9 polymorphism correlated with changes in biochemical parameters...

Adipose tissue expression of 11beta-Hydroxysteroid dehydrogenase type 1 in cushing's syndrome and in obesity

Glucocorticoids have a major role in determining adipose tissue metabolism and distribution. 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD1) is a NADPH-dependent enzyme highly expressed in the liver and adipose tissue. In most intact cells and tissues it functions as a reductase (to convert inactive cortisone to active cortisol). It has been hypothesized that tissue-specific deregulation of cortisol metabolism may be involved in the complex pathophysiology of the metabolic syndrome (MS) and obesity. Transgenic mice overexpressing 11betaHSD1 in adipose tissue develop obesity with all features of the MS, whereas 11betaHSD1-knockout mice are protected from both. The bulk of evidences points to an overexpression and increased activity of 11betaHSD1 also in human adipose tissue. However, 11betaHSD1 seems to adjust local cortisol concentrations independently of its plasma levels. In Cushing's syndrome, 11betaHSD1 is downregulated and may not be responsible for the abdominal fat depots; it also undergoes downregulation in response to weight loss in human obesity. The nonselective 11betaHSD1 inhibitor carbenoxolone improves insulin sensitivity in humans, and selective inhibitors enhance insulin action in diabetic mice liver, thereby lowering blood glucose. Thus, 11betaHSD1 is now emerging as a modulator of energy partitioning and a promising pharmacological target to treat the MS and diabetes.

Os glicocorticóides (GC) têm papel importante na determinação do metabolismo e da distribuição do tecido adiposo. A 11beta-hidroxisteróide desidrogenase tipo 1 (11betaHSD1) é uma enzima dependente de NADPH, altamente expressa nos tecidos hepático e adiposo. Em muitas células e tecidos intactos, ela funciona como redutase (convertendo cortisona em cortisol). Postula-se que uma desregulação tecido-específica do cortisol estaria envolvida na complexa fisiopatologia da síndrome metabólica (SM) e obesidade. Ratos que super-expressam 11betaHSD1 no tecido adiposo desenvolvem obesidade e todas as características da SM, enquanto ratos knockout para 11betaHSD1 são protegidos. Evidências apontam para uma super-expressão e aumento da atividade 11betaHSD1 também no tecido adiposo humano. Entretanto, a 11betaHSD1 parece ajustar a concentração local de cortisol independente da sua concentração sérica. Na síndrome de Cushing, a expressão da 11betaHSD1 é regulada para baixo, não devendo ser a causa dos depósitos de gordura visceral; em obesos, há também regulação para baixo em resposta à perda de peso. A carbenoxolona, um inibidor não seletivo da 11betaHSD1, melhora a sensibilidade insulínica em humanos e inibidores seletivos aumentam a sensibilidade insulínica hepática e melhoram o controle glicêmico em ratos diabéticos. Assim, a 11betaHSD1 está emergindo como um modulador da compartimentalização de energia e um alvo farmacológico promissor para o tratamento da SM e do diabetes.