OR09-04 Common Genetic Variants Associated with SERPINA6 Expression in Liver Influence Cortisol-Responsive Transcriptional Networks in Human Adipose Tissue

A genome wide meta-analysis by the CORtisol NETwork (CORNET) consortium⁽¹⁾ has identified genetic variants spanning the SERPINA6/SERPINA1 locus on chromosome 14, associated with morning plasma cortisol and predictive of cardiovascular disease (Crawford et al, Unpublished). SERPINA6 encodes Corticosteroid Binding Globulin (CBG), responsible for binding most cortisol in blood and putatively mediating delivery of cortisol to target tissues. We hypothesised that genetic variants in SERPINA6 influence CBG expression in liver and cortisol delivery to extra-hepatic tissues, influencing cortisol-regulated gene expression.

The Stockholm Tartu Atherosclerosis Reverse Networks Engineering Task study (STARNET)⁽²⁾ provides RNA sequencing data in 9 vascular and metabolic tissues from 600 genotyped individuals (mean age 65.8, 70.3% male) undergoing coronary artery bypass grafting. We used STARNET to identify SNPs associated with plasma cortisol at genome wide significance in CORNET as cis-eQTLs for SERPINA6 in liver and as trans-eQTLs for the expression of genes across STARNET tissues. Causal inference methodologies⁽³⁾ were then employed for the network reconstruction of these trans-genes and their downstream targets.

We identified 21 SNPs that both were associated with cortisol at genome wide significance in CORNET (p ≤ 5x10^-8) and were cis-eQTLs for SERPINA6 expression in liver (q ≤ 0.05). Moreover, these SNPs were trans-eQTLs for sets of genes in liver, subcutaneous and visceral abdominal adipose tissue, with over-representation of known glucocorticoid-regulated genes in adipose. The highest confidence gene network identified was specific to subcutaneous adipose, with the interferon regulatory trans-gene, IRF2, controlling a putative glucocorticoid-regulated network. Targets in this network include LDB2 and LIPA, both associated with coronary artery disease.

We conclude that variants in the SERPINA6/SERPINA1 locus mediate their effect on plasma cortisol through variation in SERPINA6 expression in liver, and in turn affect gene expression in extra-hepatic tissues through modulating cortisol delivery. This supports a dynamic role for CBG in modulating cortisol delivery to tissues. The cortisol-responsive gene networks identified here represent candidate pathways to mediate cardiovascular risk attributable to elevated cortisol.

(1) Bolton, et al. (2014) PLOS Genet. 10:e1004474., (2) Franzén et al. (2016). Science 353:827., (3) Wang and Michoel. (2017). PLOS Comput. Biol. 13:e1005703.

Diet-induced weight loss alters hepatic glucocorticoid metabolism in type 2 diabetes mellitus

CONTEXT

Altered tissue-specific glucocorticoid metabolism has been described in uncomplicated obesity and type 2 diabetes. We hypothesized that weight loss induced by diet and exercise, which has previously been shown to reverse abnormal cortisol metabolism in uncomplicated obesity, also normalizes cortisol metabolism in patients with type 2 diabetes.

OBJECTIVE

Test the effects of a diet intervention with added exercise on glucocorticoid metabolism.

DESIGN

Two groups followed a Paleolithic diet (PD) for 12 weeks with added 180 min of structured aerobic and resistance exercise per week in one randomized group (PDEX).

SETTING

Umeå University Hospital.

PARTICIPANTS

Men and women with type 2 diabetes treated with lifestyle modification ± metformin were included. Twenty-eight participants (PD, n = 15; PDEX, n = 13) completed measurements of glucocorticoid metabolism.

MAIN OUTCOME MEASURES

Changes in glucocorticoid metabolite levels in 24-h urine samples, expression of HSD11B1 mRNA in s.c. adipose tissue and conversion of orally administered cortisone to cortisol measured in plasma. Body composition and insulin sensitivity were measured using a hyperinsulinemic-euglycemic clamp, and liver fat was measured by magnetic resonance spectroscopy.

RESULTS

Both groups lost weight and improved insulin sensitivity. Conversion of orally taken cortisone to plasma cortisol and the ratio of 5α-THF + 5β-THF/THE in urine increased in both groups.

CONCLUSIONS

These interventions caused weight loss and improved insulin sensitivity with concomitant increases in the conversion of cortisone to cortisol, which is an estimate of hepatic HSD11B1 activity. This suggests that dysregulation of liver glucocorticoid metabolism in these patients is a consequence rather than a cause of metabolic dysfunction.

Estrogens and Glucocorticoids in Mammary Adipose Tissue: Relationships with Body Mass Index and Breast Cancer Features

CONTEXT

Adipose tissue is an important site for extragonadal steroid hormone biosynthesis through the expression and activity of P450 aromatase, 11β-hydroxysteroid dehydrogenase (HSD) 1, and 17β-HSDs. The contribution of steroid hormones produced by adjacent adipose tissue for the progression and survival of breast tumors is unknown.

OBJECTIVE

To quantify estrogens (estradiol, estrone) and glucocorticoids (cortisol, cortisone) in breast adipose tissue from both healthy and diseased women and their relationships with adiposity indices and breast cancer prognostic markers.

DESIGN AND SETTING

Breast adipose tissue was collected at time of surgery.

PATIENTS

Pre- and postmenopausal women undergoing partial mastectomy for treatment of breast cancer (n = 17) or reduction mammoplasty (n = 6) were studied.

INTERVENTIONS

Relative estrogen and glucocorticoid amounts were determined by liquid chromatography tandem mass spectrometry.

RESULTS

The targeted steroids were reliably detected and quantified in mammary adipose tissues. Women with ER+/PR+ tumor had higher relative estradiol amount than women with ER-/PR- tumor (P < .05). The ratio of estradiol-to-estrone was higher in lean women than in women with a body mass index (BMI) ≥ 25 kg/m2 (P < .05). Mixed-model analyses showed that estradiol, cortisone, and cortisol were negatively associated with tumor size (P < .05). Relationships between glucocorticoids and tumor size remained significant after adjustment for BMI. The cortisol-to-cortisone ratio was negatively associated with tumor stage (P < .05) independently of BMI.

CONCLUSIONS

We reliably quantified estrogens and glucocorticoids in breast adipose tissue from healthy women and women suffering from breast cancer. Our findings suggest that smaller breast tumors are associated with higher relative amounts of estradiol and cortisol in adipose tissue.

Estrogen metabolites in a small cohort of patients with idiopathic pulmonary arterial hypertension

Increased risk and severity of idiopathic pulmonary arterial hypertension (iPAH) is associated with elevated estradiol in men and postmenopausal women. Pulmonary arteries synthesise estradiol via aromatase and metabolise it via CYP1B1 to mitogenic metabolites; SNPs in aromatase and CYP1B1 have been associated with PAH. This suggests that estradiol metabolism could be altered in iPAH. This proof-of-concept study profiles estradiol and several metabolites of estradiol simultaneously in serum from iPAH patients and controls. We show that the estradiol and metabolite profile is altered in iPAH and that 16-hydroxyestrone and 16-hydroxyestradiol accumulate in iPAH patients with 16-hydroxyestrone levels relating to disease severity.

Highlights into the pharmacology of nutraceuticals

LINKED ARTICLES

This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc.

Maternal Glucocorticoid Metabolism Across Pregnancy: A Potential Mechanism Underlying Fetal Glucocorticoid Exposure

CONTEXT

Across pregnancy, maternal serum cortisol levels increase up to 3-fold. It is not known whether maternal peripheral cortisol metabolism and clearance change across pregnancy or influence fetal cortisol exposure and development.

OBJECTIVES

The primary study objective was to compare maternal urinary glucocorticoid metabolites, as markers of cortisol metabolism and clearance, between the second and third trimester of pregnancy. Secondary objectives were to test associations of total maternal urinary glucocorticoid excretion, with maternal serum cortisol levels and offspring birth weight z score.

DESIGN, PARTICIPANTS, AND SETTING

A total of 151 women with singleton pregnancies, recruited from prenatal clinic at the Pittsburgh site of the Measurement of Maternal Stress (MOMS) study, had 24-hour urine collections during both the second and third trimesters.

RESULTS

Between the second and third trimester, total urinary glucocorticoid excretion increased (ratio of geometric means [RGM] 1.37, 95% CI 1.22-1.52, P < .001), and there was an increase in calculated 5β-reductase compared to 5α-reductase activity (RGM 3.41, 95% CI 3.04-3.83, P < .001). During the third trimester total urinary glucocorticoid excretion and serum cortisol were negatively correlated (r = -0.179, P = .029). Mean total urinary glucocorticoid excretion across both trimesters and offspring birth weight z score were positively associated (β = 0.314, P = .001).

CONCLUSIONS

The estimated activity of maternal enzymes responsible for cortisol metabolism change between the second and third trimester of pregnancy. Additionally, maternal peripheral metabolism and clearance of cortisol may serve as a novel mechanism affecting fetal cortisol exposure and growth.

Heritability of Cortisol Production and Metabolism Throughout Adolescence

CONTEXT

Inter-individual differences in cortisol production and metabolism emerge with age and may be explained by genetic factors.

OBJECTIVE

To estimate the relative contributions of genetic and environmental factors to inter-individual differences in cortisol production and metabolism throughout adolescence.

DESIGN

Prospective follow-up study of twins.

SETTING

Nationwide register.

PARTICIPANTS

218 mono- and dizygotic twins (N = 109 pairs) born between 1995 amd 1996, recruited from the Netherlands Twin Register. Cortisol metabolites were determined in 213, 169, and 160 urine samples at the ages of 9, 12, and 17, respectively.

MAIN OUTCOME MEASURES

The total contribution of genetic factors (broad-sense heritability) and shared and unshared environmental influences to inter-individual differences in cortisol production and activities of 5α-reductase, 5β-reductase, and 11β-hydroxysteroid dehydrogenases and cytochrome P450 3A4.

RESULTS

For cortisol production rate at the ages of 9, 12, and 17, broad-sense heritability was estimated as 42%, 30%, and 0%, respectively, and the remainder of the variance was explained by unshared environmental factors. For cortisol metabolism indices, the following heritability was observed: for the A-ring reductases (5α-and 5β-reductases), broad-sense heritability increased with age (to >50%), while for the other indices (renal 11β-HSD2, global 11β-HSD, and CYP3A4), the contribution of genetic factors was highest (68%, 18%, and 67%, respectively) at age 12.

CONCLUSIONS

The contribution of genetic factors to inter-individual differences in cortisol production decreased between 12 and 17y, indicative of a predominant role of individual circumstances. For cortisol metabolism, distinct patterns of genetic and environmental influences were observed, with heritability that either increased with age or peaked at age 12y.

Simultaneous quantification of estrogens and glucocorticoids in human adipose tissue by liquid-chromatography-tandem mass spectrometry

The presence of estrogens, androgens and glucocorticoids as well as their receptors and steroid converting enzymes in adipose tissue has been established. Their contribution to diseases such as obesity, diabetes and hormone-dependent cancers is an active area of research. Our objective was to develop a LC-MS/MS method to quantify bioactive estrogens and glucocorticoids simultaneously in human adipose tissue. Estrogens and glucocorticoids were extracted from adipose tissue samples using solid-phase extraction. Estrogens were derivatized using 1-(2,4-dinitro-5-fluorophenyl)-4-methylpiperazine (PPZ) and methyl iodide to generate a permanently charged molecule (MPPZ). Steroids were separated and quantified by LC-MS/MS. The limit of quantitation for the steroids was between 15 and 100 pg per sample. Accuracy and precision were acceptable (<20%). Using this method, estradiol, estrone, cortisone and cortisol were quantified in adipose tissue from women with and without breast cancer. This novel assay of estrogens and glucocorticoids by LC-MS/MS coupled with derivatization allowed simultaneous quantification of a panel of steroids in human adipose tissue across the endogenous range of concentrations encountered in health and disease.

Higher Insulin Resistance and Adiposity in Postmenopausal Women With Breast Cancer Treated With Aromatase Inhibitors

CONTEXT

Aromatase deficiency causes obesity and insulin resistance in aromatase knockout mice and humans with rare mutations of the aromatase gene (CYP19). Aromatase inhibitors are a commonly prescribed therapy for postmenopausal breast cancer.

OBJECTIVE

We hypothesized that aromatase inhibitors induce obesity and insulin resistance when used in treatment of breast cancer.

DESIGN

Case-control study.

SETTING

University teaching hospital.

PARTICIPANTS

Patients with postmenopausal breast cancer (n = 20) treated with aromatase inhibitors and 20 age-matched control subjects.

MAIN OUTCOME MEASURES

The primary outcome measure was insulin sensitivity index - Matsuda, derived from a 75-g oral glucose tolerance test. Body composition was assessed by dual energy x-ray absorptiometry and biopsy specimens of subcutaneous adipose tissue obtained for assessment of mRNA transcript levels. Data are reported as mean ± SEM (patients receiving inhibitors vs control group, respectively).

RESULTS

Aromatase inhibitor therapy was associated with significantly lower insulin sensitivity (5.15 ± 0.45 vs 6.80 ± 0.64; P = 0.041), higher peak insulin concentration after oral glucose tolerance test (693.4 ± 78.6 vs 527.6 ± 85.5 pmol/L; P = 0.035), greater percentage of body fat (38.4% ± 1.0% vs 34.6% ± 1.3%; P = 0.026), and higher plasma leptin concentration (23.5 ± 2.8 vs 15.5 ± 2.3 ng/mL; P = 0.035).

CONCLUSION

Women who received aromatase inhibitors for postmenopausal breast cancer had greater percentage body fat and insulin resistance compared with control subjects with no history of breast cancer.

Current strategies for quantification of estrogens in clinical research

Estrogens and their bioactive metabolites play key roles in regulating diverse processes in health and disease. In particular, estrogens and estrogenic metabolites have shown both protective and non-protective effects on disease pathobiology, implicating the importance of this steroid pathway in disease diagnostics and monitoring. All estrogens circulate in a wide range of concentrations, which in some patient cohorts can be extremely low. However, elevated levels of estradiol are reported in disease. For example, in pulmonary arterial hypertension (PAH) elevated levels have been reported in men and postmenopausal women. Conventional immunoassay techniques have come under scrutiny, with their selectivity, accuracy and precision coming into question. Analytical methodologies such as gas and liquid chromatography coupled to single and tandem mass spectrometric approaches (GC-MS, GC-MS/MS, LC-MS and LC-MS/MS) have been developed to quantify endogenous estrogens and in some cases their bioactive metabolites in biological fluids such as urine, serum, plasma and saliva. Liquid-liquid or solid-phase extraction approaches are favoured with derivatization remaining a necessity for detection in lower volumes of sample. The limits of quantitation of individual assays vary but are commonly in the range of 0.5-5 pg/mL for estrone and estradiol, with limits for their bioactive metabolites being higher. This review provides an overview of current approaches for measurement of unconjugated estrogens in biological matrices by MS, highlighting the advances in this field and the challenges remaining for routine use in the clinical and research environment.

Role of Hepatic Glucocorticoid Receptor in Metabolism in Models of 5αR1 Deficiency in Male Mice

Inhibition of 5α-reductases impairs androgen and glucocorticoid metabolism and induces insulin resistance in humans and rodents. The contribution of hepatic glucocorticoids to these adverse metabolic changes was assessed using a liver-selective glucocorticoid receptor (GR) antagonist, A-348441. Mice lacking 5α-reductase 1 (5αR1-KO) and their littermate controls were studied during consumption of a high-fat diet, with or without A-348441(120 mg/kg/d). Male C57BL/6 mice (age, 12 weeks) receiving dutasteride (1.8 mg/kg/d)) or vehicle with consumption of a high-fat diet, with or without A-348441, were also studied. In the 5αR1-KO mice, hepatic GR antagonism improved diet-induced insulin resistance but not more than that of the controls. Liver steatosis was not affected by hepatic GR antagonism in either 5αR1KO mice or littermate controls. In a second model of 5α-reductase inhibition using dutasteride and hepatic GR antagonism with A-348441 attenuated the excess weight gain resulting from dutasteride (mean ± SEM, 7.03 ± 0.5 vs 2.13 ± 0.4 g; dutasteride vs dutasteride plus A-348441; P < 0.05) and normalized the associated hyperinsulinemia after glucose challenge (area under the curve, 235.9 ± 17 vs 329.3 ± 16 vs 198.4 ± 25 ng/mL/min; high fat vs high fat plus dutasteride vs high fat plus dutasteride plus A-348441, respectively; P < 0.05). However, A-348441 again did not reverse dutasteride-induced liver steatosis. Thus, overall hepatic GR antagonism improved the insulin resistance but not the steatosis induced by a high-fat diet. Moreover, it attenuated the excessive insulin resistance caused by pharmacological inhibition of 5α-reductases but not genetic disruption of 5αR1. The use of dutasteride might increase the risk of type 2 diabetes mellitus and reduced exposure to glucocorticoids might be beneficial.

SAT-009 Proof of Concept That Corticosterone Has a Higher Therapeutic Index Than Hydrocortisone in Patients with Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) is associated with poor health outcomes. This is, in part, because doses of glucocorticoid which are sufficient to suppress excess adrenal androgens are also associated with adverse metabolic effects such as insulin resistance. This toxicity occurs with efficacious doses of all commonly prescribed glucocorticoids (hydrocortisone, prednisolone and dexamethasone). However, the glucocorticoid corticosterone may have an improved therapeutic index because of its unusual susceptibility to export from cells by ATP-binding cassette (ABC) transporters. ABCB1 is expressed in the brain and exports cortisol (hydrocortisone), prednisolone and dexamethasone, limiting their potency at suppressing ACTH. However, corticosterone is not exported by ABCB1 but is exported by the alternative ABCC1 transporter. Expression of ABCC1 is relatively low compared to ABCB1 in the brain, however ABCC1 is expressed in the absence of ABCB1 in adipose tissue, muscle and bone, potentially limiting corticosterone action in these tissues. We hypothesized that corticosterone may be more efficacious at suppressing ACTH and adrenal androgens but with less metabolic toxicity than hydrocortisone. Fourteen adults with classic CAH due to 21-hydroxylase deficiency were recruited to a double-blind randomised crossover study comparing intravenous infusions of placebo, hydrocortisone and deuterated (D8) corticosterone. Subjects attended after omitting their usual glucocorticoid for 12h and were administered glucocorticoid/placebo for 5.5 hours in a two-step infusion designed to achieve concentrations of 400 and 800nM. Blood samples were collected regularly. Circulating D8-corticosterone concentrations were approximately 30% higher than hydrocortisone. D8-corticosterone suppressed ACTH, androstenedione and 17-hydroxyprogesterone to a greater extent than hydrocortisone. However, hydrocortisone increased circulating insulin compared with D8-corticosterone and placebo (10.0±1.3 vs 8.3±1.2 vs 7.2±1.3mU/L respectively, P<0.05). Blood pressure and FFAs were similar between phases. Thus, corticosterone acutely suppresses ACTH and adrenal androgens in CAH patients without causing hyperinsulinaemia. Corticosterone may be a better glucocorticoid replacement than hydrocortisone for the treatment of CAH.

Incidence of type 2 diabetes mellitus in men receiving steroid 5α-reductase inhibitors: population based cohort study

OBJECTIVE

To investigate the incidence of new onset type 2 diabetes mellitus in men receiving steroid 5α-reductase inhibitors (dutasteride or finasteride) for long term treatment of benign prostatic hyperplasia.

DESIGN

Population based cohort study.

SETTING

UK Clinical Practice Research Datalink (CPRD; 2003-14) and Taiwanese National Health Insurance Research Database (NHIRD; 2002-12).

PARTICIPANTS

Men in the CPRD who received dutasteride (n=8231), finasteride (n=30 774), or tamsulosin (n=16 270) were evaluated. Propensity score matching (2:1; dutasteride to finasteride or tamsulosin) produced cohorts of 2090, 3445, and 4018, respectively. In the NHIRD, initial numbers were 1251 (dutasteride), 4194 (finasteride), and 86 263 (tamsulosin), reducing to 1251, 2445, and 2502, respectively, after propensity score matching.

MAIN OUTCOMES MEASURE

Incident type 2 diabetes using a Cox proportional hazard model.

RESULTS

In the CPRD, 2081 new onset type 2 diabetes events (368 dutasteride, 1207 finasteride, and 506 tamsulosin) were recorded during a mean follow-up time of 5.2 years (SD 3.1 years). The event rate per 10 000 person years was 76.2 (95% confidence interval 68.4 to 84.0) for dutasteride, 76.6 (72.3 to 80.9) for finasteride, and 60.3 (55.1 to 65.5) for tamsulosin. There was a modest increased risk of type 2 diabetes for dutasteride (adjusted hazard ratio 1.32, 95% confidence interval 1.08 to 1.61) and finasteride (1.26, 1.10 to 1.45) compared with tamsulosin. Results for the NHIRD were consistent with the findings for the CPRD (adjusted hazard ratio 1.34, 95% confidence interval 1.17 to 1.54 for dutasteride, and 1.49, 1.38 to 1.61 for finasteride compared with tamsulosin). Propensity score matched analyses showed similar results.

CONCLUSIONS

The risk of developing new onset type 2 diabetes appears to be higher in men with benign prostatic hyperplasia exposed to 5α-reductase inhibitors than in men receiving tamsulosin, but did not differ between men receiving dutasteride and those receiving finasteride. Additional monitoring might be required for men starting these drugs, particularly in those with other risk factors for type 2 diabetes.

Data for analysis of catechol estrogen metabolites in human plasma by liquid chromatography tandem mass spectrometry

Analysis of catechol estrogens (2 & 4 hydroxy-estrone and estradiol) has proven troublesome by liquid chromatography tandem mass spectrometry due to their low concentrations, short half-lives and temperature-labile nature. Derivatization to methyl piperazine analogues has been reported for a panel of 9 estrogens in, "Derivatization enhances analysis of estrogens and their bioactive metabolites in human plasma by liquid chromatography tandem mass spectrometry" (Denver et al., 2019). Data show alteration of the base catalyst in this method was required to allow detection of catechol estrogens to low levels. Data also highlight the challenges faced in chromatographic separation of isomers and isotopologues, which were partially overcome by employing an extended column length and reduced oven temperature. In addition, data analysis displayed significant matrix effects during quantitation in plasma, following solid-phase extraction, despite efficient recoveries.

Derivatization enhances analysis of estrogens and their bioactive metabolites in human plasma by liquid chromatography tandem mass spectrometry

Estrogens regulate many diverse biological processes in health and disease. They circulate at a wide range of concentrations in females generating several active metabolites (hydroxy and methoxyestrogens). The metabolites are assumed to be present in much lower levels and are thought to contribute to diseases such as pulmonary arterial hypertension (PAH). Estrogen metabolites are challenging to quantify in plasma and currently available immunoassays are non-specific. Here we have developed and validated a novel assay to simultaneously quantify parent estrogens and their metabolites by mass spectrometry (MS).

Estrogens were extracted from human plasma using solid phase extraction and derivatized using 1-(5-fluoro-2, 4-dinitrophenyl)-4-methylpiperazine (PPZ) before quaternization by methylation (“MPPZ”). MPPZ derivatives were separated and quantified by liquid chromatography tandem MS (LC-MS/MS) in positive electrospray ionization mode, using a QTrap 6500 + coupled to a Shimadzu Nexera X2. Separation was achieved using an ACE Excel 2 C18-PFP column (2 μm, 2.1 mm × 150 mm). The limits of quantification (LOQ) were 0.43–2.17 pg on column with a linear range from 2 or 10 - 2000 pg mL^-1. Intra and inter-day precision and accuracy were acceptable (<20% at LOQ and <15% above). These derivatives demonstrated minimal degradation upon short-term storage at 15 °C (<20%) and longer term at −20 °C (<20%). Using this approach, estrone (E1) and estradiol (E2) were detected in plasma (0.5 mL) from healthy women and those with PAH but downstream metabolites 16-hydroxy-E1, 16-hydroxy-E2, 2-methoxy-E1 and 4-methoxy-E1 were only detected in plasma from diseased patients. These findings will next be tested robustly in large patient cohorts.

This novel LC-MS/MS analysis of estrogens and their bioactive metabolites, using MPPZ derivatization, opens doors for the simultaneous analysis of a panel of estrogens in human plasma, across the endogenous range of concentrations encountered in health and disease.

•

LC-MS/MS method for simultaneous quantification of estrogens and their bioactive metabolites in human plasma.

•

High recoveries and reduced matrix effects using MCX-SPE^® extraction cartridges followed by MPPZ derivatization.

•

Generation of stable derivatives allowing quantification of estrogens in low endogenous levels.

Pulsatility of glucocorticoid hormones in pregnancy: Changes with gestation and obesity

OBJECTIVE

Hypothalamic-pituitary-adrenal axis (HPA) activity is decreased in obese pregnancy and associates with increased foetal size. Pulsatile release of glucocorticoid hormones regulates their action in target tissues. Glucocorticoids are essential for normal foetal growth, but little is known about glucocorticoid pulsatility in pregnancy. We aimed to investigate the ultradian rhythm of glucocorticoid secretion during obese and lean pregnancy and nonpregnancy.

DESIGN

Serum cortisol, cortisone, corticosterone and 11-dehydrocorticosterone were measured by LC-MS/MS from samples obtained at 10-minute intervals between 08.00-11.00 hours and 16.00-19.00 hours, from 8 lean (BMI <25 kg/m² ) and 7 obese (BMI > 35 kg/m² ) pregnant women between 16-24 weeks gestation and again at 30-36 weeks), and nonpregnant controls (lean n = 3, obese n = 4) during the luteal phase of their menstrual cycle. Interstitial fluid cortisol was measured by ELISA, from samples obtained using a portable microdialysis and automated collection device at 20-minute intervals over 24 hours.

RESULTS

Serum cortisol AUC, highest peak and lowest trough increased significantly with gestation in lean and obese pregnant compared with nonpregnant subjects. Pulsatility of cortisol was detected in interstitial fluid. In pregnant subjects, interstitial fluid pulse frequency was significantly lower with advancing gestation in obese, but not in lean.

CONCLUSIONS

We demonstrate cortisol pulsatility in interstitial fluid. Pulse frequency is altered with increased gestation and BMI. This may be a novel mechanism to explain decreased HPA activity in obese pregnancy.

Species-specific regulation of angiogenesis by glucocorticoids reveals contrasting effects on inflammatory and angiogenic pathways

Glucocorticoids are potent inhibitors of angiogenesis in the rodent in vivo and in vitro but the mechanism by which this occurs has not been determined. Administration of glucocorticoids is used to treat a number of conditions in horses but the angiogenic response of equine vessels to glucocorticoids and, therefore, the potential role of glucocorticoids in pathogenesis and treatment of equine disease, is unknown. This study addressed the hypothesis that glucocorticoids would be angiostatic both in equine and murine blood vessels.The mouse aortic ring model of angiogenesis was adapted to assess the effects of cortisol in equine vessels. Vessel rings were cultured under basal conditions or exposed to: foetal bovine serum (FBS; 3%); cortisol (600 nM), cortisol (600nM) plus FBS (3%), cortisol (600nM) plus either the glucocorticoid receptor antagonist RU486 or the mineralocorticoid receptor antagonist spironolactone. In murine aortae cortisol inhibited and FBS stimulated new vessel growth. In contrast, in equine blood vessels FBS alone had no effect but cortisol alone, or in combination with FBS, dramatically increased new vessel growth compared with controls. This effect was blocked by glucocorticoid receptor antagonism but not by mineralocorticoid antagonism. The transcriptomes of murine and equine angiogenesis demonstrated cortisol-induced down-regulation of inflammatory pathways in both species but up-regulation of pro-angiogenic pathways selectively in the horse. Genes up-regulated in the horse and down-regulated in mice were associated with the extracellular matrix. These data call into question our understanding of glucocorticoids as angiostatic in every species and may be of clinical relevance in the horse.

Transfer and Metabolism of Cortisol by the Isolated Perfused Human Placenta

CONTEXT

Fetal overexposure to glucocorticoids in utero is associated with fetal growth restriction and is postulated to be a key mechanism linking suboptimal fetal growth with cardiovascular disease in later life.

OBJECTIVE

To develop a model to predict maternal-fetal glucocorticoid transfer. We hypothesized placental 11-β-hydroxysteroid dehydrogenase-type 2 (11β-HSD2) would be the major rate-limiting step in maternal cortisol transfer to the fetus.

DESIGN

We used a deuterated cortisol tracer in the ex vivo placental perfusion model, in combination with computational modeling, to investigate the role of interconversion of cortisol and its inactive metabolite cortisone on transfer of cortisol from mother to fetus.

PARTICIPANTS

Term placentas were collected from five women with uncomplicated pregnancies, at elective caesarean delivery.

INTERVENTION

Maternal artery of the isolated perfused placenta was perfused with D4-cortisol.

MAIN OUTCOME MEASURES

D4-cortisol, D3-cortisone, and D3-cortisol were measured in maternal and fetal venous outflows.

RESULTS

D4-cortisol, D3-cortisone, and D3-cortisol were detected and increased in maternal and fetal veins as the concentration of D4-cortisol perfusion increased. D3-cortisone synthesis was inhibited when 11-β-hydroxysteroid dehydrogenase (11β-HSD) activity was inhibited. At the highest inlet concentration, only 3.0% of the maternal cortisol was transferred to the fetal circulation, whereas 26.5% was metabolized and 70.5% exited via the maternal vein. Inhibiting 11β-HSD activity increased the transfer to the fetus to 7.3% of the maternal input, whereas 92.7% exited via the maternal vein.

CONCLUSIONS

Our findings challenge the concept that maternal cortisol diffuses freely across the placenta and confirm that 11β-HSD2 acts as a major "barrier" to cortisol transfer to the fetus.

Principles of pharmacological research of nutraceuticals

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

ABCC1 confers tissue-specific sensitivity to cortisol versus corticosterone: A rationale for safer glucocorticoid replacement therapy

The aim of treatment in congenital adrenal hyperplasia is to suppress excess adrenal androgens while achieving physiological glucocorticoid replacement. However, current glucocorticoid replacement regimes are inadequate because doses sufficient to suppress excess androgens almost invariably induce adverse metabolic effects. Although both cortisol and corticosterone are glucocorticoids that circulate in human plasma, any physiological role for corticosterone has been neglected. In the brain, the adenosine 5'-triphosphate-binding cassette transporter ABCB1 exports cortisol but not corticosterone. Conversely, ABCC1 exports corticosterone but not cortisol. We show that ABCC1, but not ABCB1, is expressed in human adipose and that ABCC1 inhibition increases intracellular corticosterone, but not cortisol, and induces glucocorticoid-responsive gene transcription in human adipocytes. Both C57Bl/6 mice treated with the ABCC1 inhibitor probenecid and FVB mice with deletion of Abcc1 accumulated more corticosterone than cortisol in adipose after adrenalectomy and corticosteroid infusion. This accumulation was sufficient to increase glucocorticoid-responsive adipose transcript expression. In human adipose tissue, tissue corticosterone concentrations were consistently low, and ABCC1 mRNA was up-regulated in obesity. To test the hypothesis that corticosterone effectively suppresses adrenocorticotropic hormone (ACTH) without the metabolic adverse effects of cortisol, we infused cortisol or corticosterone in patients with Addison's disease. ACTH suppression was similar, but subcutaneous adipose transcripts of glucocorticoid-responsive genes were higher after infusion with cortisol rather than with corticosterone. These data indicate that corticosterone may be a metabolically favorable alternative to cortisol for glucocorticoid replacement therapy when ACTH suppression is desirable, as in congenital adrenal hyperplasia, and justify development of a pharmaceutical preparation.

Plasma metabolomic profile varies with glucocorticoid dose in patients with congenital adrenal hyperplasia

Glucocorticoid replacement therapy is the mainstay of treatment for congenital adrenal hyperplasia (CAH) but has a narrow therapeutic index and dose optimisation is challenging. Metabolomic profiling was carried out on plasma samples from 117 adults with 21-hydroxylase deficiency receiving their usual glucocorticoid replacement therapy who were part of the CaHASE study. Samples were profiled by using hydrophilic interaction chromatography with high resolution mass spectrometry. The patients were also profiled using nine routine clinical measures. The data were modelled by using both multivariate and univariate statistics by using the clinical metadata to inform the choice of patient groupings. Comparison of 382 metabolites amongst groups receiving different glucocorticoid doses revealed a clear distinction between patients receiving ≤5 mg (n = 64) and >5 mg (n = 53) daily prednisolone-equivalent doses. The 24 metabolites which were statistically significantly different between groups included free fatty acids, bile acids, and amino acid metabolites. Using 7 metabolites improved the receiver operating characteristic with area under the curve for predicting glucocorticoid dose of >0.9 with FDR adjusted P values in the range 3.3 E-04 -1.9 E-10. A combination of seven plasma metabolite biomarkers readily discriminates supraphysiological glucocorticoid replacement doses in patients with CAH.

Acute interaction between hydrocortisone and insulin alters the plasma metabolome in humans

With the aim of identifying biomarkers of glucocorticoid action and their relationship with biomarkers of insulin action, metabolomic profiling was carried out in plasma samples from twenty healthy men who were administered either a low or medium dose insulin infusion (n = 10 each group). In addition, all subjects were given metyrapone (to inhibit adrenal cortisol secretion) + /− hydrocortisone (HC) in a randomised crossover design to produce low, medium and high glucocorticoid levels. The clearest effects of insulin were to reduce plasma levels of the branched chain amino acids (BCAs) leucine/isoleucine and their deaminated metabolites, and lowered free fatty acids and acylcarnitines. The highest dose of hydrocortisone increased plasma BCAs in both insulin groups but increased free fatty acids only in the high insulin group, however hydrocortisone did not affect the levels of acyl carnitines in either group. The clearest interaction between HC and insulin was that hydrocortisone produced an elevation in levels of BCAs and their metabolites which were lowered by insulin. The direct modulation of BCAs by glucocorticoids and insulin may provide the basis for improved in vivo monitoring of glucocorticoid and insulin action.

Gas chromatography tandem mass spectrometry offers advantages for urinary steroids analysis

Gas chromatography mass spectrometry has been the lynchpin of clinical assessment of steroid profiles for ∼3 decades. The improvements in assay performance offered by tandem mass spectrometry were assessed. Across the spectrum of glucocorticoid and androgen analytes tested, limits of detection and quantitation were ∼20 fold lower with triple than single quadrupole systems, but the more noticeable improvement was that signal to noise was substantially improved and the linear range wider. These benefits allowed more reliable and concomitant measurement of steroids with substantially different abundances and in smaller volumes of urine.

Carbonyl reductase 1 catalyzes 20β-reduction of glucocorticoids, modulating receptor activation and metabolic complications of obesity

Carbonyl Reductase 1 (CBR1) is a ubiquitously expressed cytosolic enzyme important in exogenous drug metabolism but the physiological function of which is unknown. Here, we describe a role for CBR1 in metabolism of glucocorticoids. CBR1 catalyzes the NADPH- dependent production of 20β-dihydrocortisol (20β-DHF) from cortisol. CBR1 provides the major route of cortisol metabolism in horses and is up-regulated in adipose tissue in obesity in horses, humans and mice. We demonstrate that 20β-DHF is a weak endogenous agonist of the human glucocorticoid receptor (GR). Pharmacological inhibition of CBR1 in diet-induced obesity in mice results in more marked glucose intolerance with evidence for enhanced hepatic GR signaling. These findings suggest that CBR1 generating 20β-dihydrocortisol is a novel pathway modulating GR activation and providing enzymatic protection against excessive GR activation in obesity.