Effect of 11 beta-hydroxysteroid dehydrogenase-1 inhibition on hepatic glucose metabolism in the conscious dog

11β-HSD1 inhibition in men mitigates prednisolone-induced adverse effects in a proof-of-concept randomised double-blind placebo-controlled trial

Glucocorticoids prescribed to limit inflammation, have significant adverse effects. As 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) regenerates active glucocorticoid, we investigated whether 11β-HSD1 inhibition with AZD4017 could mitigate adverse glucocorticoid effects without compromising their anti-inflammatory actions. We conducted a proof-of-concept, randomized, double-blind, placebo-controlled study at Research Unit, Churchill Hospital, Oxford, UK (NCT03111810). 32 healthy male volunteers were randomized to AZD4017 or placebo, alongside prednisolone treatment. Although the primary endpoint of the study (change in glucose disposal during a two-step hyperinsulinemic, normoglycemic clamp) wasn't met, hepatic insulin sensitivity worsened in the placebo-treated but not in the AZD4017-treated group. Protective effects of AZD4017 on markers of lipid metabolism and bone turnover were observed. Night-time blood pressure was higher in the placebo-treated but not in the AZD4017-treated group. Urinary (5aTHF+THF)/THE ratio was lower in the AZD4017-treated but remained the same in the placebo-treated group. Most anti-inflammatory actions of prednisolone persisted with AZD4017 co-treatment. Four adverse events were reported with AZD4017 and no serious adverse events. Here we show that co-administration of AZD4017 with prednisolone in men is a potential strategy to limit adverse glucocorticoid effects.

Inhibition of 11β-Hydroxysteroid dehydrogenase-1 with AZD4017 in patients with nonalcoholic steatohepatitis or nonalcoholic fatty liver disease: A randomized, double-blind, placebo-controlled, phase II study

AIM

To evaluate whether short-term treatment with a selective 11β-Hydroxysteroid dehydrogenase-1 (11β-HSD1) inhibitor, AZD4017, would block hepatic cortisol production and thereby decrease hepatic fat in patients with nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH), with or without type 2 diabetes (T2D).

MATERIALS AND METHODS

This was a randomized, double-blind, placebo-controlled, phase 2 study conducted at two sites. Key inclusion criteria were the presence of NAFLD or NASH on magnetic resonance imaging (MRI) or recent biopsy positive for NASH. Enrolled patients were randomly assigned (1:1) to AZD4017 or placebo for 12 weeks. Primary outcomes were between-group differences in mean change from baseline to week 12 in liver fat fraction (LFF) and conversion of ¹³ C cortisone to ¹³ C cortisol in the liver.

RESULTS

A total of 93 patients were randomized; 85 patients completed treatment. The mean (standard deviation [SD]) change in LFF was -0.667 (5.246) and 0.139 (4.323) in the AZD4017 and placebo groups (P = 0.441). For patients with NASH and T2D, the mean (SD) change in LFF was significantly improved in the AZD4017 versus the placebo group (-1.087 [5.374] vs. 1.675 [3.318]; P = 0.033). Conversion of ¹³ C cortisone to ¹³ C cortisol was blocked in all patients in the AZD4017 group. There were no significant between-group differences (AZD4017 vs. placebo) in changes in fibrosis, weight, levels of liver enzymes or lipids, or insulin sensitivity.

CONCLUSION

Although the study did not meet one of the primary outcomes, AZD4017 blocked the conversion of ¹³ C cortisone to ¹³ C cortisol in the liver in all patients who received the drug. In patients with NASH and T2D, AZD4017 improved liver steatosis versus placebo.

11β Hydroxysteroid dehydrogenase - 1 activity in type 2 diabetes mellitus: a comparative study

BACKGROUND

A comparative study of 11 β HSD 1 activity in type 2 diabetes mellitus subjects with respect to fasting blood glucose and other metabolic parameters was conducted.

METHODS

A case control experimental study was performed enrolling thirty type 2 diabetes mellitus patients and thirty age, gender and BMI matched controls using cortisone acetate test.

RESULTS

The rise of serum cortisol after oral 25 mg cortisone acetate from baseline (dexamethasone suppressed level) is higher in subjects with type 2 diabetes and is associated with exercise, BMI, SGOT but not daily calorie intake, lipid parameters and thyroid status. Fasting blood glucose after overnight 1 mg oral dexamethasone is a strong predictor of 11HSD1 activity, irrespective of presence of type 2 diabetes.

CONCLUSION

11β HSD 1 activity is higher in type 2 diabetes mellitus subjects, especially those who are lean. Future 11 β HSD 1 inhibitors targeting metabolic syndrome, will be most useful in those with increased fasting blood glucose. The role of DHEAS and vitamin D status needs to be explored.

Hepatic glycogen can regulate hypoglycemic counterregulation via a liver-brain axis

Liver glycogen is important for the counterregulation of hypoglycemia and is reduced in individuals with type 1 diabetes (T1D). Here, we examined the effect of varying hepatic glycogen content on the counterregulatory response to low blood sugar in dogs. During the first 4 hours of each study, hepatic glycogen was increased by augmenting hepatic glucose uptake using hyperglycemia and a low-dose intraportal fructose infusion. After hepatic glycogen levels were increased, animals underwent a 2-hour control period with no fructose infusion followed by a 2-hour hyperinsulinemic/hypoglycemic clamp. Compared with control treatment, fructose infusion caused a large increase in liver glycogen that markedly elevated the response of epinephrine and glucagon to a given hypoglycemia and increased net hepatic glucose output (NHGO). Moreover, prior denervation of the liver abolished the improved counterregulatory responses that resulted from increased liver glycogen content. When hepatic glycogen content was lowered, glucagon and NHGO responses to insulin-induced hypoglycemia were reduced. We conclude that there is a liver-brain counterregulatory axis that is responsive to liver glycogen content. It remains to be determined whether the risk of iatrogenic hypoglycemia in T1D humans could be lessened by targeting metabolic pathway(s) associated with hepatic glycogen repletion.

Effects of acute glucocorticoid blockade on metabolic dysfunction in patients with Type 2 diabetes with and without fatty liver

To investigate the potential of therapies which reduce glucocorticoid action in patients with Type 2 diabetes we performed a randomized, double-blinded, placebo-controlled crossover study of acute glucocorticoid blockade, using the glucocorticoid receptor antagonist RU38486 (mifepristone) and cortisol biosynthesis inhibitor (metyrapone), in 14 men with Type 2 diabetes. Stable isotope dilution methodologies were used to measure the rates of appearance of glucose, glycerol, and free fatty acids (FFAs), including during a low-dose (10 mU·m⁻² ·min⁻¹) hyperinsulinemic clamp, and subgroup analysis was conducted in patients with high or low liver fat content measured by magnetic resonance spectroscopy (n = 7/group). Glucocorticoid blockade lowered fasting glucose and insulin levels and improved insulin sensitivity of FFA and glycerol turnover and hepatic glucose production. Among this population with Type 2 diabetes high liver fat was associated with hyperinsulinemia, higher fasting glucose levels, peripheral and hepatic insulin resistance, and impaired suppression of FFA oxidation and FFA and glycerol turnover during hyperinsulinemia. Glucocorticoid blockade had similar effects in those with and without high liver fat. Longer term treatments targeting glucocorticoid action may be useful in Type 2 diabetes with and without fatty liver.

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.

Mechanisms of glucocorticoid-induced insulin resistance: focus on adipose tissue function and lipid metabolism

Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin resistance, obesity, cardiovascular disease, and ultimately decreased survival, despite their potent anti-inflammatory effects. This apparent paradox may be explained by the complex actions of GCs on adipose tissue functionality. The wide prevalence of oral GC therapy makes their adverse systemic effects an important yet incompletely understood clinical problem. This article reviews the mechanisms by which supraphysiologic GC exposure promotes insulin resistance, focusing in particular on the effects on adipose tissue function and lipid metabolism.

Evaluation of liver glycogen catabolism during hypercortisolism induced by the administration of dexamethasone in rats

BACKGROUND

The contribution of liver glycogen catabolism to hyperglycemia and glucose intolerance induced by pharmacological hypercortisolism were investigated.

METHODS

For this purpose, adult male Wistar rats that received 1.0 mg/kg dexamethasone (DEX) ip at 8:00 a.m. (DEX group) or saline (CON group) once a day for 5 consecutive days were compared.

RESULTS

Experimental hypercortisolism was confirmed by higher (p<0.05) glycemia, lower (p<0.05) body weight and glucose intolerance. In the fed state, the basal glycogen catabolism and the glucagon (1 nM) and epinephrine (2 μM) induced glycogen catabolism were similar between the groups. The activation of glycogen catabolism induced by phenylephrine (2 μM) and isoproterenol (20 μM) were increased (p<0.05) and decreased (p<0.05), respectively, in DEX rats. Furthermore, DEX rats exhibited higher (p<0.05) glycogen catabolism during the infusion of cAMP (3 μM). However, during the infusion of cAMP (15 μM), 6MB-cAMP (3 μM) or cyanide (0.5 mM), the intensification of glycogen breakdown was similar. Thus, in general, hypercortisolism does not influence the basal glycogen catabolism and the liver responsiveness to glycogenolytic agents in the fed state. In contrast with fed state, fasted rats (DEX group) showed a more intense (p<0.05) basal glycogen catabolism.

CONCLUSION

The contribution of glycogen catabolism to hyperglycemia during hypercortisolism depends of the nutritional status, starting from a negligible participation in the fed state up to a significant contribution in the fasted state.

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.

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.

Effects of intraportal exenatide on hepatic glucose metabolism in the conscious dog

Incretins improve glucose metabolism through multiple mechanisms. It remains unclear whether direct hepatic effects are an important part of exenatide's (Ex-4) acute action. Therefore, the objective of this study was to determine the effect of intraportal delivery of Ex-4 on hepatic glucose production and uptake. Fasted conscious dogs were studied during a hyperglycemic clamp in which glucose was infused into the hepatic portal vein. At the same time, portal saline (control; n = 8) or exenatide was infused at low (0.3 pmol·kg⁻¹·min⁻¹, Ex-4-low; n = 5) or high (0.9 pmol·kg⁻¹·min⁻¹, Ex-4-high; n = 8) rates. Arterial plasma glucose levels were maintained at 160 mg/dl during the experimental period. This required a greater rate of glucose infusion in the Ex-4-high group (1.5 ± 0.4, 2.0 ± 0.7, and 3.7 ± 0.7 mg·kg⁻¹·min⁻¹ between 30 and 240 min in the control, Ex-4-low, and Ex-4-high groups, respectively). Plasma insulin levels were elevated by Ex-4 (arterial: 4,745 ± 428, 5,710 ± 355, and 7,262 ± 1,053 μU/ml; hepatic sinusoidal: 14,679 ± 1,700, 15,341 ± 2,208, and 20,445 ± 4,020 μU/ml, 240 min, area under the curve), whereas the suppression of glucagon was nearly maximal in all groups. Although glucose utilization was greater during Ex-4 infusion (5.92 ± 0.53, 6.41 ± 0.57, and 8.12 ± 0.54 mg·kg⁻¹·min⁻¹), when indices of hepatic, muscle, and whole body glucose uptake were expressed relative to circulating insulin concentrations, there was no indication of insulin-independent effects of Ex-4. Thus, this study does not support the notion that Ex-4 generates acute changes in hepatic glucose metabolism through direct effects on the liver.

Effects of 11β-hydroxysteroid dehydrogenase-1 inhibition on hepatic glycogenolysis and gluconeogenesis

The aim of this study was to determine the effect of prolonged 11β-hydroxysteroid dehydrogenase-1 (11β-HSD1) inhibition on basal and hormone-stimulated glucose metabolism in fasted conscious dogs. For 7 days prior to study, either an 11β-HSD1 inhibitor (HSD1-I; n = 6) or placebo (PBO; n = 6) was administered. After the basal period, a 4-h metabolic challenge followed, where glucagon (3×-basal), epinephrine (5×-basal), and insulin (2×-basal) concentrations were increased. Hepatic glucose fluxes did not differ between groups during the basal period. In response to the metabolic challenge, hepatic glucose production was stimulated in PBO, resulting in hyperglycemia such that exogenous glucose was required in HSD-I (P < 0.05) to match the glycemia between groups. Net hepatic glucose output and endogenous glucose production were decreased by 11β-HSD1 inhibition (P < 0.05) due to a reduction in net hepatic glycogenolysis (P < 0.05), with no effect on gluconeogenic flux compared with PBO. In addition, glucose utilization (P < 0.05) and the suppression of lipolysis were increased (P < 0.05) in HSD-I compared with PBO. These data suggest that inhibition of 11β-HSD1 may be of therapeutic value in the treatment of diseases characterized by insulin resistance and excessive hepatic glucose production.

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.

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.

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.