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Gareth G Lavery,
Jan Idkowiak,
Mark Sherlock,
Iwona Bujalska,
Jon P Ride,
Khalid Saqib,
Michaela F Hartmann, Beverly Hughes,
Stefan A Wudy,
Jean De Schepper,
Wiebke Arlt,
Nils Krone,
Cedric H Shackleton,
Elizabeth A Walker,
Paul M Stewart
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ABSTRACT: CONTEXT: Inactivating mutations in the enzyme hexose-6-phosphate dehydrogenase (H6PDH- encoded by H6PD) causes Apparent Cortisone Reductase Deficiency (ACRD). H6PDH generates cofactor NADPH for 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1 encoded by HSD11B1) oxo-reductase activity, converting cortisone to cortisol. Inactivating mutations in HSD11B1 cause true cortisone reductase deficiency (CRD). Both ACRD and CRD present with HPA axis activation and adrenal hyperandrogenism. OBJECTIVE: To describe the clinical, biochemical and molecular characteristics of two additional female children with ACRD, and to illustrate the diagnostic value of urinary steroid profiling in identifying and differentiating a total of six ACRD and four CRD cases. DESIGN: Clinical, biochemical, and genetic assessment of two female patients presenting during childhood. In addition, results of urinary steroid profiling in a total of ten ACRD/ CRD patients were compared to identify distinguishing characteristics. RESULTS: Case 1 was compound heterozygous for R109AfsX3, and a novel P146L missense mutation in H6PD. Case 2 was compound heterozygous for novel nonsense mutations Q325X and Y446X in H6PD. Mutant expression studies confirmed loss of H6PDH activity in both cases. Urinary steroid metabolite profiling by gas chromatography/ mass spectrometry (GC/MS) suggested ACRD in both cases. In addition, we were able to establish a steroid metabolite signature differentiating ACRD and CRD, providing a basis for genetic diagnosis and future individualized management. CONCLUSIONS: Steroid profile analysis of a 24h-urine collection provides a diagnostic method for discriminating between ACRD and CRD. This will provide a useful tool in stratifying unresolved adrenal hyperandrogenism in children with premature adrenarche, and adult females with PCOS.
European Journal of Endocrinology 11/2012; · 3.42 Impact Factor
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Gareth G Lavery,
Agnieszka E Zielinska,
Laura L Gathercole, Beverly Hughes,
Nina Semjonous,
Phillip Guest,
Khalid Saqib,
Mark Sherlock,
Gary Reynolds,
Stuart A Morgan,
Jeremy W Tomlinson,
Elizabeth A Walker,
Elizabeth H Rabbitt,
Paul M Stewart
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ABSTRACT: Glucocorticoids (GC) are implicated in the development of metabolic syndrome, and patients with GC excess share many clinical features, such as central obesity and glucose intolerance. In patients with obesity or type 2 diabetes, systemic GC concentrations seem to be invariably normal. Tissue GC concentrations determined by the hypothalamic-pituitary-adrenal (HPA) axis and local cortisol (corticosterone in mice) regeneration from cortisone (11-dehydrocorticosterone in mice) by the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme, principally expressed in the liver. Transgenic mice have demonstrated the importance of 11β-HSD1 in mediating aspects of the metabolic syndrome, as well as HPA axis control. In order to address the primacy of hepatic 11β-HSD1 in regulating metabolism and the HPA axis, we have generated liver-specific 11β-HSD1 knockout (LKO) mice, assessed biomarkers of GC metabolism, and examined responses to high-fat feeding. LKO mice were able to regenerate cortisol from cortisone to 40% of control and had no discernible difference in a urinary metabolite marker of 11β-HSD1 activity. Although circulating corticosterone was unaltered, adrenal size was increased, indicative of chronic HPA stimulation. There was a mild improvement in glucose tolerance but with insulin sensitivity largely unaffected. Adiposity and body weight were unaffected as were aspects of hepatic lipid homeostasis, triglyceride accumulation, and serum lipids. Additionally, no changes in the expression of genes involved in glucose or lipid homeostasis were observed. Liver-specific deletion of 11β-HSD1 reduces corticosterone regeneration and may be important for setting aspects of HPA axis tone, without impacting upon urinary steroid metabolite profile. These discordant data have significant implications for the use of these biomarkers of 11β-HSD1 activity in clinical studies. The paucity of metabolic abnormalities in LKO points to important compensatory effects by HPA activation and to a crucial role of extrahepatic 11β-HSD1 expression, highlighting the contribution of cross talk between GC target tissues in determining metabolic phenotype.
Endocrinology 05/2012; 153(7):3236-48. · 4.46 Impact Factor
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ABSTRACT: In peripheral target tissues, levels of active glucocorticoid hormones are controlled by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), a dimeric enzyme that catalyzes the reduction of cortisone to cortisol within the endoplasmic reticulum. Loss of this activity results in a disorder termed cortisone reductase deficiency (CRD), typified by increased cortisol clearance and androgen excess. To date, only mutations in H6PD, which encodes an enzyme supplying cofactor for the reaction, have been identified as the cause of disease. Here we examined the HSD11B1 gene in two cases presenting with biochemical features indicative of a milder form of CRD in whom the H6PD gene was normal. Novel heterozygous mutations (R137C or K187N) were found in the coding sequence of HSD11B1. The R137C mutation disrupts salt bridges at the subunit interface of the 11β-HSD1 dimer, whereas K187N affects a key active site residue. On expression of the mutants in bacterial and mammalian cells, activity was either abolished (K187N) or greatly reduced (R137C). Expression of either mutant in a bacterial system greatly reduced the yield of soluble protein, suggesting that both mutations interfere with subunit folding or dimer assembly. Simultaneous expression of mutant and WT 11β-HSD1 in bacterial or mammalian cells, to simulate the heterozygous condition, indicated a marked suppressive effect of the mutants on both the yield and activity of 11β-HSD1 dimers. Thus, these heterozygous mutations in the HSD11B1 gene have a dominant negative effect on the formation of functional dimers and explain the genetic cause of CRD in these patients.
Proceedings of the National Academy of Sciences 02/2011; 108(10):4111-6. · 9.68 Impact Factor
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ABSTRACT: Nonalcoholic fatty liver disease represents the hepatic manifestation of the metabolic syndrome. Nonalcoholic steatohepatitis (NASH) is the progressive form of liver injury. The pathophysiology that leads to NASH is not well understood.
We hypothesize that an altered cortisol metabolism in the liver may be a pathogenetic factor.
75 patients (28 men, 47 women) underwent liver biopsy for elevation in liver enzymes. Histological diagnosis identified normal liver in eight, fatty liver in 20, NASH grade 1 in 22, grade 2 in nine, grade 3 in three patients, and other forms of hepatitis or cirrhosis in 13 patients. We quantified hepatic 11beta-hydroxysteroid dehydrogenase type1 (11beta-HSD1) and hexose-6-phosphate-dehydrogenase (H6PDH) mRNA expression by real-time PCR. In addition, analysis of 24 h urinary excretion of cortisol metabolites using GCMS was performed and compared with healthy controls.
11beta-HSD1 mRNA expression correlated significantly (R2= 0.809; P < 0.001) with H6PDH mRNA expression, negatively with waist-to-hip ratio in women (R2= 0.394; P= 0.005), but not with urinary (THF + 5alpha-THF)/THE ratio, total cortisol metabolite excretion, age, BMI, degree of fatty liver or NASH stages. Total cortisol metabolite excretion was increased in patients with fatty liver or NASH compared with healthy controls.
Our data suggest that expression of hepatic 11beta-HSD1 and H6PDH are closely interlinked. 11beta-HSD1 gene expression does not seem to be involved in the pathogenesis of fatty liver or NASH. However, those patients showed an increased 5alpha- and 5beta-reduction of cortisol leading to an increased cortisol turnover rate and an activation of the HPA axis.
Clinical Endocrinology 08/2008; 70(4):554-60. · 3.17 Impact Factor
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ABSTRACT: The incidence of childhood obesity and type 2 diabetes has reached epidemic proportions. Glucocorticoid excess causes central obesity and diabetes mellitus as seen in Cushing's syndrome. The 11beta-hydroxysteroid dehydrogenase type 1 enzyme (11beta-HSD1) regenerates active cortisol from inactive cortisone. Altered 11beta-HSD1 may cause tissue-specific Cushing's syndrome with central obesity and impaired glucose homeostasis.
Clinical and laboratory characteristics, and anthropometric measurements were determined in 15 male and 6 female obese pubertal children (aged 12-18 years, Tanner stages 2-5). In addition, analyses of 24-h excretion rates of glucocorticoids were also performed in 21 age-, sex-, and pubertal stage-matched non-obese children using gas chromatographic-mass spectrometric (GC-MS) analysis.
11beta-HSD1 activity (urinary tetrahydrocortisol (THF) + 5alpha-THF/tetrahydrocortisone (THE) ratio) was lower in obese when compared with non-obese boys. In addition, obese children had a higher total cortisol metabolite excretion than non-obese children. 11beta-HSD1 activity was significantly related to age in lean and obese children. Standard deviation score (SDS)-body mass index did not correlate with 11beta-HSD1 activity, or with total cortisol metabolite excretion within each group. In obese children, 11beta-HSD1 activity and total cortisol metabolite excretion showed no correlation to waist-to-hip ratio, fat mass (percentage of body mass), or the homeostasis model assessment of insulin resistance index.
In conclusion, our findings strongly suggest that 11beta-HSD1 activity increases with age, and is reduced in obese boys. In addition, obese children have a higher total cortisol metabolites excretion suggesting a stimulated hypothalamus-pituitary-adrenal axis.
European Journal of Endocrinology 10/2007; 157(3):319-24. · 3.42 Impact Factor
