Corticosteroid-binding Globulin Concentrations Research Articles

ODP584 Corticosteroid-binding Globulin Deficiency Independently Predicts Mortality and is Associated with Norepinephrine Requirements in Septic Shock.

Abstract Context: Hydrocortisone administration in septic shock remains controversial. Corticosteroid-binding globulin (CBG) transports cortisol to inflammatory sites and is depleted in septic shock. Objective To determine if severely deficient plasma CBG <200 nmol/L (Ref range 269-641 nmol/L) independently predicts septic shock mortality. Methods A prospective observational study in patients with septic shock. Patients were categorised into two groups: mean plasma CBG concentrations <200 nmol/L and ≥200 nmol/L (day 1/2), with additional categorisation by nadir CBG. Primary outcome was Intensive Care Unit (ICU) mortality. Secondary outcomes were 28- and 90-day mortality, norepinephrine requirements, renal-replacement therapy, and clinician-instituted hydrocortisone. Results 135 patients were included. Mortality rates in ICU were higher in the CBG <200 nmol/L vs the CBG ≥200 nmol/L group: 32.4% vs 13.9%; Odds ratio (OR), 2.97, (95% confidence intervals (CI) 1.19,7.41); P=0. 02: 28-days; OR 2.25 (95% CI 0.99,5.11): 90-days; OR 2.21 (95% CI 0.99,4.91). Multivariate analysis revealed 4 factors independently associated with ICU mortality: CBG <200 nmol/L (OR 3.23, 95% CI 1. 06,9.88), Acute Physiology and Chronic Health Evaluation (APACHE) II >25 (OR 3.58, 95% CI 1.20,10.68); Sequential [Sepsis-related] Organ Failure Assessment (SOFA) liver score (OR 1.98, 95% CI 1. 04,3.72); and renal-replacement therapy (OR 6.59, 95% CI 2.17,20. 01). Nadir CBG levels were associated with higher SOFA cardiovascular scores, norepinephrine total dose (ug) P<0. 01 and duration (days) P<0. 01. Plasma cortisol concentrations and hydrocortisone administration did not relate to ICU mortality. Conclusion Septic shock patients with CBG <200 nmol/L had higher norepinephrine requirements and 3.2-fold higher ICU mortality. CBG concentration was the only directly reversible independent mortality risk factor. Presentation: No date and time listed

Corticosteroid-binding Globulin (SERPINA6) Establishes Postpubertal Sex Differences in Rat Adrenal Development.

Encoded by SerpinA6, plasma corticosteroid-binding globulin (CBG) transports glucocorticoids and regulates their access to cells. We determined how CBG influences plasma corticosterone and adrenal development in rats during the pubertal to adult transition using CRISPR/cas9 to disrupt SerpinA6 gene expression. In the absence of CBG, total plasma corticosterone levels were ∼80% lower in adult rats of both sexes, with a greater absolute reduction in females than in males. Notably, free corticosterone and adrenocorticotropic hormone were comparable between all groups. Between 30 and 90 days of age, wild-type female rats showed increases in adrenal weight and the size of the corticosterone-producing region, the zona fasciculata (zf), in tandem with increases in plasma CBG and corticosterone concentrations, whereas no such changes were observed in males. This sex difference was lost in rats without CBG, such that adrenal growth and zf expansion were similar between sexes. The sex-specific effects of CBG on adrenal morphology were accompanied by remarkable changes in gene expression: ∼40% of the adrenal transcriptome was altered in females lacking CBG, whereas almost no effect was seen in males. Over half of the adrenal genes that normally exhibit sexually dimorphic expression after puberty were similarly expressed in males and females without CBG, including those responsible for cholesterol biosynthesis and mobilization, steroidogenesis, and growth. Rat adrenal SerpinA6 transcript levels were very low or undetectable. Thus, sex differences in adrenal growth, morphology and gene expression profiles that emerge during puberty in rats are dependent on concomitant increases in plasma CBG produced by the liver.

Corticosteroid-Binding Globulin Deficiency Independently Predicts Mortality in Septic Shock.

Hydrocortisone administration in septic shock remains controversial. Corticosteroid-binding globulin (CBG) transports cortisol to inflammatory sites and is depleted in septic shock. To determine whether severely deficient serum CBG < 200 nmol/L (reference range 269-641 nmol/L) independently predicts septic shock mortality. A prospective observational study in patients with septic shock. Patients were categorized into 2 groups: mean plasma CBG concentrations <200 nmol/L and ≥200 nmol/L (day 1/2), with additional categorization by nadir CBG. Primary outcome was intensive care unit (ICU) mortality. Secondary outcomes were 28- and 90-day mortality, norepinephrine requirements, renal replacement therapy, and clinician-instituted hydrocortisone. 135 patients were included. Mortality rates in ICU were higher in the CBG < 200 nmol/L vs the CBG ≥ 200 nmol/L group: 32.4% vs 13.9% [odds ratio (OR) 2.97 (95% CI 1.19, 7.41); P = 0.02] with 28-day mortality OR 2.25 (95% CI 0.99, 5.11) and 90-day mortality OR 2.21 (95% CI 0.99, 4.91). Multivariate analysis revealed 4 factors independently associated with ICU mortality: CBG < 200 nmol/L (adjusted OR 3.23, 95% CI 1.06, 9.88), Acute Physiology and Chronic Health Evaluation II > 25 (adjusted OR 3.58, 95% CI 1.20, 10.68), Sequential Organ Failure Assessment (SOFA) liver score (adjusted OR 1.98, 95% CI 1.04, 3.72), and renal replacement therapy (adjusted OR 6.59, 95% CI 2.17, 20.01). Nadir CBG levels were associated with higher SOFA cardiovascular scores and norepinephrine total dose (μg; P < 0.01) and duration (days; P < 0.01). Plasma cortisol concentrations and hydrocortisone administration did not relate to ICU mortality. Septic shock patients with CBG < 200 nmol/L had higher norepinephrine requirements and 3.2-fold higher ICU mortality. CBG concentration was the only directly reversible independent mortality risk factor.

Decreased maximal cortisol secretion rate in patients with cirrhosis: Relation to disease severity

Background & AimsHepatic enzymes play a major role in the metabolic elimination of cortisol, and reduced rates of cortisol clearance have been consistently observed in patients with chronic liver disease. It is less clear whether there are concomitant abnormalities of adrenocortical function in patients with cirrhosis. In the present study, we sought to assess adrenocortical function in patients with cirrhosis using measures of free cortisol appearance and elimination rates that are independent of serum concentrations of cortisol binding proteins.MethodsPost hoc analysis used computer-assisted numerical and modelling methods with serial total and free cortisol concentration data to obtain rates of free cortisol appearance and elimination. Rate parameters were obtained in 114 patients with chronic liver disease, including Child-Pugh (CP) ≤8 (n = 53) and CP >8 (n = 61).ResultsMaximal cortisol secretion rate (CSRmax) was significantly decreased (p = 0.01) in patients with cirrhosis with CP >8 (0.28 nM/s; 95% CI 0.24–0.34) compared with those with CP ≤8 (0.39 nM/s; 95% CI 0.33–0.46), and CSRmax was negatively correlated with CP score (r = −0.19, p = 0.01). Free cortisol elimination rate was significantly (p = 0.04) decreased in the CP >8 group (0.16 ± 0.20 min−1) compared with that in the CP ≤8 group (0.21 ± 0.21 min−1), and free cortisol elimination rates were negatively correlated with CP score (r = −0.23, p = 0.01). A significant correlation between CSRmax and free cortisol elimination rate (r = 0.88, p <0.001) was observed.ConclusionsCSRmax and free cortisol elimination rates were significantly reduced according to severity of cirrhosis. In contrast to stimulated total cortisol concentrations, CSRmax estimates were independent of cortisol-binding protein concentrations. Results provide additional evidence of subnormal adrenocortical function in patients with cirrhosis.Lay summaryWe applied numerical analytic methods to characterise adrenocortical function in patients with varying stages of chronic liver disease. We found that patients with more severe cirrhosis have decreased rate of free cortisol elimination and decreased maximal cortisol secretion rate, which is a measure of adrenocortical function. In contrast to conventional measures of adrenocortical function, those obtained using numerical methods were not affected by variation in corticosteroid binding globulin and albumin concentrations. We conclude that patients with cirrhosis demonstrate measurable abnormalities of adrenocortical function, evidence of which supports aspects of the hepatoadrenal syndrome hypothesis.

Are serum cortisol measurements by immunoassays reliable?: A case series.

Routinely used automated immunoassays have been found to give unrealiable measurements of thyroid hormones in the presence of either high or low levels of thyroxine-binding globulin. Thyroid hormones are not the only analytes bound to specific binding proteins that are measured by immunoassays. Preliminary data from a series of cases, comparing IA measurements to those obtained by liquid chromatography-tandem mass spectrometry, reveal for the first time that IA measurements report falsely low (by an average of 27%) serum cortisol concentrations. Initial findings suggest that IA measurements of serum cortisol are affected by high concentrations of corticosteroid binding globulin.

Effect of omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation to lactating sows on growth and indicators of stress in the postweaned pig1,2.

Dietary omega-3 polyunsaturated fatty acids (n-3 PUFA) are precursors for lipid metabolites that reduce inflammation. Two experiments were conducted to test the hypothesis that enriching the sow diet in n-3 PUFA during late gestation and throughout lactation reduces stress and inflammation and promotes growth in weaned pigs. A protected fish oil product (PFO; Gromega) was used to enrich the diet in n-3 PUFA. In the initial experiment, time-bred gilts were fed a gestation and lactation diet supplemented with 0% (control; n = 5), 0.25% (n = 4), 0.5% (n = 4), or 1% (n = 5) PFO from 101 ± 2 d of gestation to day 16 of lactation. Adding 1% PFO to the diet increased the n-3:n-6 PUFA ratio in colostrum and milk compared with controls (P = 0.05). A subsequent experiment was performed to determine whether supplementing the sow diet with 1% PFO improved growth and reduced circulating markers of acute inflammation and stress in the offspring. Plasma was harvested from piglets (16 per treatment group) on day 0 (d of weaning) and days 1 and 3 postweaning. Pigs from the 1% PFO treatment group weighed more (P = 0.03) on day 3 postweaning and had a greater (P ˂ 0.05) n-3:n-6 PUFA ratio in plasma on each day sampled compared with 0% PFO controls. There was an overall treatment effect on plasma total cortisol (P = 0.03) and haptoglobin (P = 0.04), with lesser concentrations in pigs on the 1% PFO diet. Plasma corticosteroid-binding globulin (CBG) concentrations were not different between treatment groups but were less (P ˂ 0.001) on days 1 and 3 when compared with day 0. The resultant free cortisol index [FCI (cortisol/CBG)] was less (P = 0.02) on days 1 and 3 for pigs from the 1% treatment group compared with the controls. An ex vivo lipopolysaccharide (LPS) challenge of whole blood collected on days 0 and 1 was used to determine whether 1% PFO attenuated release of inflammatory cytokines (IL-1β, IL-6, and TNF-α). Blood from pigs within the 1% PFO treatment group tended (P = 0.098) to have a lesser mean concentration of TNF-α in response to LPS compared with blood from controls. These results suggest that providing a PFO supplement as 1% of the diet to sows beginning in late gestation and during lactation can increase the n-3:n-6 PUFA ratio in their offspring, which may improve growth and reduce the acute physiological stress response in the pigs postweaning.

Post-Stress Fructose and Glucose Ingestion Exhibit Dissociable Behavioral and Physiological Effects.

An acute traumatic event can lead to lifelong changes in stress susceptibility and result in psychiatric disease such as Post-Traumatic Stress Disorder (PTSD). We have previously shown that access to a concentrated glucose solution for 24 h beginning immediately after trauma decreased stress-related pathology in the learned helplessness model of PTSD and comorbid major depression. The current study sought to investigate the peripheral physiological effects of post-stress glucose consumption. We exposed 128 male Sprague-Dawley rats to inescapable and unpredictable 1-milliamp electric tail shocks or simple restraint in the learned helplessness procedure. Rats in each stress condition had access to a 40% glucose solution, 40% fructose solution, or water. Blood and liver tissue were extracted and processed for assay. We assessed corticosterone, corticosteroid-binding globulin (CBG), glucose, and liver glycogen concentrations at various time points following stress. We found that rats given access to glucose following exposure to traumatic shock showed a transient rise in blood glucose and an increase in liver glycogen repletion compared to those that received water or fructose following exposure to electric shock. We also found that animals given glucose following shock exhibited reduced free corticosterone and increased CBG compared to their water-drinking counterparts. However, this difference was not apparent when glucose was compared to fructose. These data suggest that post-stress glucose prophylaxis is likely not working via modulation of the HPA axis, but rather may provide its benefit by mitigating the metabolic challenges of trauma exposure.

The impact of early-life stress on corticosteroid carrier protein levels and 11β-hydroxysteroid dehydrogenase 1 expression in adolescent rats.

Corticosteroid-binding globulin (CBG), albumin and 11β-hydroxysteroid dehydrogenase (11β-HSD) enzymes play crucial roles in the bioavailability of glucocorticoids. Downstream of the adrenal glands, these proteins affect glucocorticoid levels in target tissues. Early-life stress (ELS) is known to program glucocorticoid action at many levels. The effects of ELS on the concentrations and synthesis of CBG and albumin and on the expression of 11β-HSD remain unclear. The maternal separation (MS) procedure in rats on postnatal days 1-14 was used as a model of ELS. On postnatal day 35 (adolescence), the serum corticosterone, CBG and albumin concentrations of male rats were measured by ELISA, while the mRNA and protein levels of CBG, albumin and 11β-HSD1 in the liver and brain were examined by RT-qPCR and Western blot, respectively. Under basal conditions, MS rats displayed lower levels of serum CBG and albumin. However, MS did not affect CBG or albumin synthesis in the liver, suggesting that the half-life and/or secretion of these proteins were influenced by MS. Additionally, MS rats showed increased protein expression of 11β-HSD1, specifically in the medial prefrontal cortex. These results indicate that ELS may potentially program glucocorticoid action through its effects on glucocorticoid bioavailability in tissues.

Opposite Expression of Hepatic and Pulmonary Corticosteroid-Binding Globulin in Cystic Fibrosis Patients.

Cystic fibrosis (CF) is characterized by a chronic pulmonary inflammation. In CF, glucocorticoids (GC) are widely used, but their efficacy and benefit/risk ratio are still debated. In plasma, corticosteroid-binding globulin (CBG) binds 90% of GC and delivers them to the inflammatory site. The main goal of this work was to study CBG expression in CF patients in order to determine whether CBG could be used to optimize GC treatment. The expression of CBG was measured in liver samples from CF cirrhotic and non-CF cirrhotic patients by qPCR and Western blot and in lung samples from non-CF and CF patients by qPCR. CBG binding assays with 3H-cortisol and the measurement of the elastase/α1-antitrypsin complex were performed using the plasmas. CBG expression increased in the liver at the transcript and protein level but not in the plasma of CF patients. This is possibly due to an increase of plasmatic elastase. We demonstrated that pulmonary CBG was expressed in the bronchi and bronchioles and its expression decreased in the CF lungs, at both levels studied. Despite the opposite expression of hepatic and pulmonary CBG in CF patients, the concentration of CBG in the plasma was normal. Thus, CBG might be useful to deliver an optimized synthetic GC displaying high affinity for CBG to the main inflammatory site in the context of CF, e.g., the lung.

78 Influence of Synchronization of Ovulation and Pregnancy on Concentrations of Corticosteroid-Binding Globulin (CBG) in Beef Heifers.

78 Influence of Synchronization of Ovulation and Pregnancy on Concentrations of Corticosteroid-Binding Globulin (CBG) in Beef Heifers.

The role of corticosteroid-binding globulin in the evaluation of adrenal insufficiency.

Cortisol is a hydrophobic molecule that is largely bound to corticosteroid-binding globulin (CBG) in the circulation. In the assessment of adrenal insufficiency, many clinicians measure a total serum cortisol level, which assumes that CBG is present in normal concentrations and with a normal binding affinity for cortisol. CBG concentration and affinity are affected by a number of common factors including oral contraceptive pills (OCPs), fever and infection, as well as rare mutations in the serine protease inhibitor A6 (SERPINA6) gene, and as such, total cortisol levels might not be the ideal way to assess adrenal function in all clinical circumstances. This paper reviews the limitations of immunoassay and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the measurement of total cortisol, the challenges of measuring free serum cortisol directly as well as the difficulties in calculating an estimated free cortisol from total cortisol, CBG and albumin concentrations. Newer approaches to the evaluation of adrenal insufficiency, including the measurement of cortisol and cortisone in the saliva, are discussed and a possible future role for these tests is proposed.

Characterization of Cortisol Secretion Rate in Secondary Adrenal Insufficiency.

Context:In secondary adrenal insufficiency (SAI), chronic deficiency of adrenocorticotropin (ACTH) is believed to result in secondary changes in adrenocortical function, causing an altered dose-response relationship between ACTH concentration and cortisol secretion rate (CSR).Objective:We sought to characterize maximal cortisol secretion rate (CSRmax) and free cortisol half-life in patients with SAI, compare results with those of age-matched healthy controls, and examine the influence of predictor variables on ACTH-stimulated cortisol concentrations.Design:CSRmax was estimated from ACTH1-24 (250 μg)–stimulated cortisol time-concentration data. Estimates for CSRmax and free cortisol half-life were obtained for both dexamethasone (DEX) and placebo pretreatment conditions for all subjects.Setting:Single academic medical center.Patients:Patients with SAI (n = 10) compared with age-matched healthy controls (n = 21).Interventions:The order of DEX vs placebo pretreatment was randomized and double-blind. Cortisol concentrations were obtained at baseline and at intervals for 120 minutes after ACTH1-24.Main Outcome Measures:CSRmax and free cortisol half-life were obtained by numerical modeling analysis. Predictors of stimulated cortisol concentrations were evaluated using a multivariate model.Results:CSRmax was significantly (P < 0.001) reduced in patients with SAI compared with controls for both placebo (0.17 ± 0.09 vs 0.46 ± 0.14 nM/s) and DEX (0.18 ± 0.13 vs 0.43 ± 0.13 nM/s) conditions. Significant predictors of ACTH1-24–stimulated total cortisol concentrations included CSRmax, free cortisol half-life, and baseline total cortisol, corticosteroid-binding globulin, and albumin concentrations (all P < 0.05).Conclusions:Our finding of significantly decreased CSRmax confirms that SAI is associated with alterations in the CSR-ACTH dose-response curve. Decreased CSRmax contributes importantly to the laboratory diagnosis of SAI.

Differential Effects of Estrogen on Corticosteroid-Binding Globulin Forms Suggests Reduced Cleavage in Pregnancy.

Corticosteroid-binding globulin (CBG) is secreted as high-affinity CBG (haCBG), which may be cleaved by tissue proteases to low-affinity CBG (laCBG), releasing free cortisol. Pregnancy and the estrogen-based combined oral contraceptive pill (COCP) increase CBG concentrations twofold to threefold. The relative effects of these two hyperestrogenic states on the CBG affinity forms are unknown. We performed an observational study in 30 pregnant women, 27 COCP takers and 23 controls. We analyzed circulating total CBG, haCBG, laCBG, and free and total cortisol concentrations. In pregnancy, total CBG and haCBG were increased compared to controls (both P < 0.0001); however, laCBG concentrations were similar. In COCP takers, total CBG and haCBG were increased [802 ± 41 vs compared to controls (both P < 0.0001)], but laCBG was also increased (P = 0.03). Pregnancy and use of COCP were associated with a comparable rise in haCBG, but laCBG was lower in pregnancy (P < 0.0001). These results were consistent with an estrogen-mediated increase in CBG synthesis in both hyperestrogenemic states but with reduced CBG cleavage in pregnancy relative to the COCP, perhaps due to pregnancy-induced CBG glycosylation. Speculatively, increased circulating haCBG concentrations in pregnancy may provide an increased reservoir of CBG-bound cortisol to prepare for the risk of puerperal infection or allow for cortisol binding in the face of competition from increased circulating progesterone concentrations.

63 EQUINE FOLLICLES MODULATE CORTISOL LEVELS AND CAPABILITY OF OOCYTES TO ADAPT TO STRESS SITUATIONS

Glucocorticoids are mediators of the systemic stress response. Acute or chronic stress characterised by high cortisol concentrations in the periphery impairs reproductive function in a variety of species and therefore may affect fertility. The ovary has been shown to be a target tissue for glucocorticoids in many species, including the mare. This study hypothesised that the equine ovary possesses internal mechanisms to modulate cortisol activity and that supraphysiologic levels of glucocorticoids do not affect oocyte IVM rates. Light horse mares (n = 9) were used in this study. Growing follicles from an induced follicular wave were divided into the following groups: G1: 5–9 mm, G2: 10–14 mm, G3: 15–19 mm, G4: 20–24 mm, and G5: ≥25 mm. Follicular fluid (FF) and compact cumulus‐oocyte complexes (COCs) were obtained by ultrasound-guided transvaginal aspiration. Blood samples were collected at the beginning and the end of every aspiration session. Cortisol (DE1887, Demeditec, Kiel-Wellsee, Germany), progesterone (ADI-901–011, Enzo Life Sciences, Farmingdale, NY, USA), and corticosteroid binding globulin (CBG, MBS047353, MyBioSource, San Diego, CA, USA) concentrations were determined by ELISA. COCs (n = 80) were randomly distributed to either the control group (DMEM-F12+ medium) or the following hydrocortisone treatment groups: 0.1 µg mL–1, 1 µg mL–1, 5 µg mL–1, 10 µg mL–1. Maturation rate was assessed 30 h after incubation. Statistical analysis was performed with the SPSS Statistics 22 software. Data were analysed using one-way ANOVA, Pearson correlation, and chi-squared test. Cortisol (115.4 ± 13.3 ng mL–1) and progesterone (22.1 ± 3.1 ng mL–1) FF concentrations were higher (P &lt; 0.05) in G5 follicles than in all other groups, and were positively correlated (r = 0.8; P &lt; 0.001). Plasma concentrations of cortisol (118.6 ± 7.8 v. 120.3 ± 12.2 ng mL–1), progesterone (2.4 ± 0.5 v. 2.5 ± 0.4 ng mL–1), and CBG (11.1 ± 5.1 v. 9.9 ± 3.2 µg mL–1) did not differ before and after follicle aspiration. However, plasma CBG and progesterone were negatively correlated (r = –0.56; P &lt; 0.01). Maturation rates did not differ among groups, regardless of the hydrocortisone concentration added to the culture medium. Our results demonstrated higher cortisol concentrations in preovulatory follicles in vivo, suggesting its importance for oocyte maturation. The greater unbound cortisol available in the FF of preovulatory follicles can be indicative of the displacement of cortisol from CBG in favour of progesterone. Furthermore, equine oocytes were capable of surviving cortisol concentrations 100 times higher than those physiologically present in preovulatory follicles. This finding suggests the ability of equine oocytes to modulate cortisol levels and adapt to stress situations.

Reversible increase in maximal cortisol secretion rate in septic shock.

Cortisol clearance is reduced in sepsis and may contribute to the development of impaired adrenocortical function that is thought to contribute to the pathophysiology of critical illness-related corticosteroid insufficiency. We sought to assess adrenocortical function using computer-assisted numerical modeling methodology to characterize and compare maximal cortisol secretion rate and free cortisol half-life in septic shock, sepsis, and healthy control subjects. Post hoc analysis of previously published total cortisol, free cortisol, corticosteroid-binding globulin, and albumin concentration data. Single academic medical center. Subjects included septic shock (n = 45), sepsis (n = 25), and healthy controls (n = 10). I.v. cosyntropin (250 μg). Solutions for maximal cortisol secretion rate and free cortisol half-life were obtained by least squares solution of simultaneous, nonlinear differential equations that account for free cortisol appearance and elimination as well as reversible binding to corticosteroid-binding globulin and albumin. Maximal cortisol secretion rate was significantly greater in septic shock (0.83 nM/s [0.44, 1.58 nM/s] reported as median [lower quartile, upper quartile]) compared with sepsis (0.51 nM/s [0.36, 0.62 nM/s]; p = 0.007) and controls (0.49 nM/s [0.42, 0.62 nM/s]; p = 0.04). The variance of maximal cortisol secretion rate in septic shock was also greater than that of sepsis or control groups (F test, p < 0.001). Free cortisol half-life was significantly increased in septic shock (4.6 min [2.2, 6.3 min]) and sepsis (3.0 min [2.3, 4.8 min] when compared with controls (2.0 min [1.2, 2.6 min]) (both p < 0.004). Results obtained by numerical modeling are consistent with comparable measures obtained by the gold standard stable isotope dilution method. Septic shock is associated with generally not only higher levels but also greater variance of maximal cortisol secretion rate when compared with control and sepsis groups. Additional studies would be needed to determine whether assessment of cortisol kinetic parameters such as maximal cortisol secretion rate and free cortisol half-life is useful in the diagnosis or management of critical illness-related corticosteroid insufficiency.

Comparison of Total Cortisol, Free Cortisol, and Surrogate Markers of Free Cortisol in Diagnosis of Adrenal Insufficiency in Patients With Stable Cirrhosis

Measurements of serum levels of total cortisol can overestimate the prevalence of adrenal dysfunction in patients with cirrhosis because they have low concentrations of corticosteroid-binding globulin and albumin. We used measurements of serum total cortisol and serum free cortisol after the low-dose short Synacthen test (LDSST) to assess adrenal dysfunction. We studied 79 patients with stable cirrhosis; adrenal dysfunction was defined by peak concentrations of total cortisol ≤494 mmol/L and/or peak concentrations of free cortisol ≤33 nmol/L after the LDSST. We determined free cortisol index (FCI) scores and calculated free cortisol levels by using Coolens' equation. The Cox regression model was used to assess the relationship between adrenal dysfunction and outcomes (death or liver transplant). On the basis of measurement of total cortisol, 34% of patients had adrenal dysfunction, and on the basis of measurement of free cortisol, 29% had adrenal dysfunction. There was agreement between total cortisol and free cortisol levels in 22% of patients; in 13%, adrenal dysfunction was diagnosed only on the basis of total cortisol and in 6% only on the basis of free cortisol (κ coefficient, 0.56; P < .01). Low concentrations of corticosteroid-binding globulin (21 vs 54 μg/mL, P < .01) led to an overestimation of adrenal dysfunction that was based on measurement of total cortisol. Measurements of calculated free cortisol constantly overestimated free cortisol concentrations, with variations as large as 87% for baseline values and up to 84% after stimulation. Adrenal insufficiency, defined by FCI scores <12, was detected in 30% of patients; among them, 23% also had subnormal peak levels of free cortisol (κ coefficient, 0.70; P < .001). Adrenal dysfunction was not significantly associated with patient outcomes, on the basis of Cox model analysis. Adrenal insufficiency, defined by LDSST, is frequent in patients with stable cirrhosis, on the basis of measurements of total and free cortisol. FCI scores are better than measurement of total cortisol in assessing adrenal function in patients with cirrhosis. We did not associate adrenal dysfunction with outcome, but further studies are needed.

Size at birth, morning cortisol and cardiometabolic risk markers in healthy Indian children

Prenatal programming of the hypothalamic-pituitary-adrenal (HPA) axis may link reduced foetal growth with higher adult chronic disease risk. South Asians have a high prevalence of low birth weight and a thin-fat phenotype, which is associated with subsequent type 2 diabetes and the metabolic syndrome. Altered HPA activity could be one of the pathological processes underlying this link. Plasma morning cortisol and corticosteroid-binding globulin (CBG) concentrations were determined in 528 children aged 9·5 years from a prospective birth cohort in India. They had detailed anthropometry at birth, and current measurements of anthropometry, plasma glucose, insulin and lipid concentrations and blood pressure. Insulin resistance (Homeostasis Model Assessment) and insulin secretion (the 30-min insulin increment) were also assessed. None of the birth measurements were associated with cortisol concentrations, but both birth weight (P = 0·03) and length (P = 0·004) were inversely associated with CBG concentrations. Cortisol concentrations were inversely associated with current body mass index (P = 0·02), and positively associated with glucose (fasting: P < 0·001; 30-min: P = 0·002) concentrations, and systolic blood pressure (P = 0·005), but not insulin resistance or the insulin increment. Higher morning cortisol is associated with higher cardiometabolic risk markers in Indian children. Although cortisol concentrations did not appear to be related to birth size, small size at birth was associated with higher CBG levels, and may be one of the processes by which foetal undernutrition affects adult health. The findings suggest a need for dynamic testing of HPA axis activity (such as measuring stress responses).

Effects of low and high protein:carbohydrate ratios in the diet of pregnant gilts on maternal cortisol concentrations and the adrenocortical and sympathoadrenal reactivity in their offspring1,2

Inadequate maternal nutrition during gestation may cause an adverse environment for the fetus leading to alterations of the hypothalamic-pituitary-adrenal (HPA) and sympatho-adrenomedullary (SAM) systems later in life. In the present study, we investigated the effects of diets with low and high protein:carbohydrate ratios on cortisol concentrations of pregnant gilts as well as the long-term effects on the function of the HPA and SAM axes in their offspring. Throughout gestation, 33 German Landrace gilts were fed high (HP, 30%), low (LP, 6.5%), or adequate (AP, 12.1%) protein diets, which were made isocaloric by adjusting the carbohydrate content. The salivary cortisol concentrations of the sows were measured in the course of the gestation period. The offspring were cross-fostered, and the plasma cortisol and catecholamine concentrations of the offspring were determined on postnatal d (PND) 1 and 27 and under specific challenging conditions: after weaning (PND 29) and after ACTH and insulin challenges (PND 68 and 70, respectively). Glucocorticoid receptor (GR) binding and neurotransmitter concentrations were measured in stress-related brain regions, and histological analyses of the adrenal were performed. Maternal salivary cortisol concentrations increased throughout gestation (P < 0.001) and the LP gilts had greater salivary cortisol compared with the AP and HP gilts (P < 0.05). No differences between diets were found for cortisol, corticosteroid-binding globulin, and catecholamine concentrations in plasma and for GR binding in hippocampus and hypothalamus in piglets at PND 1 and 27. However, the cortisol response to weaning was increased in LP piglets (P < 0.05), and in HP offspring the basal plasma noradrenaline concentrations were increased (P < 0.05). The cortisol response to the ACTH and the insulin challenge did not differ between diets. On PND 81, an increased adrenal medulla area was observed in LP offspring compared with the AP offspring (P < 0.05). Our results show that maternal diets with aberrant protein:carbohydrate ratios during gestation have moderate long-term effects on the function of the HPA and SAM system in the offspring, which indicates that pigs show a considerable plasticity to cope with maternal malnutrition.

Analysis of baseline hypothalamic-pituitary-adrenal activity in late adolescence reveals gender specific sensitivity of the stress axis

Dysfunctional regulation of the hypothalamic-pituitary-adrenal (HPA) axis has been proposed as an important biological mechanism underlying stress-related diseases; however, a better understanding of the interlinked neuroendocrine events driving the release of cortisol by this stress axis is essential for progress in preventing or halting irreversible development of adverse HPA-function. We aimed to investigate basal HPA-activity in a normal population in late adolescence, the time of life believed to overlap with HPA-axis maturation and establishment of a lasting set point level of HPA function. A total of 1258 participants (mean age 16.6 years) recruited from the Western Australian Pregnancy (Raine) Cohort provided fasting morning blood and saliva samples for basal HPA activity assessment. Irrespective of gender, linear regression modelling identified a positive correlation between the main components of the HPA-cascade of events, ACTH, total cortisol and free cortisol in saliva. Corticosteroid binding globulin (CBG) was inversely associated with free cortisol in saliva, an effect most clearly observed in boys. ACTH levels were lower, but cortisol levels were higher in girls than in boys. Girls may also be exposed to more bioactive cortisol, based on higher average free cortisol measured in saliva at awakening. These relatively higher female free cortisol levels were significantly reduced by oral contraceptive use, eliminating the gender specific difference in salivary cortisol. Free plasma cortisol, calculated from total circulating cortisol and CBG concentrations, was also significantly reduced in girls using oral contraceptives, possibly via an enhancing effect of oral contraceptives on blood CBG content. This study highlights a clear gender difference in HPA activity under non-stressful natural conditions. This finding may be relevant for research into sex-specific stress-related diseases with a typical onset in late adolescence.

Free Cortisol and Accuracy of Total Cortisol Measurements in the Diagnosis of Adrenal Insufficiency in Brain-dead Patients

After brain death, adrenal insufficiency (AI) is very common and may be one of the mechanisms that contributes to hemodynamic instability and loss of potential organ donors. However, when diagnosed by total cortisol measurement, critically ill patients may be overdiagnosed as having AI. The aims of this study were to assess the prevalence of AI when diagnosed using free cortisol measurement and the accuracy of total cortisol measurement to diagnose AI in brain-dead patients. All consecutive brain-dead patients were included in this single-center noninterventional clinical observation study. Assessment of adrenocorticotropin, corticosteroid-binding globulin, baseline and tetracosactin-stimulated serum free and total cortisol concentrations were performed. AI was defined as a baseline free cortisol concentration ≤ 55 nM(-1) and/or Δ free cortisol ≤ 55 nM(-1). Patients were considered to have a low albumin concentration if less than 25 g · L(-1) and a low corticosteroid-binding globulin concentration if less than 27 mg · L(-1) in men or 31 mg · L(-1) in women. Among the 42 included patients, the incidence of AI was 83% (95% CI, 69-93%). Baseline total cortisol was correlated with baseline free cortisol, whatever the albumin or corticosteroid-binding globulin concentration. The area under the receiver operating characteristic curve of baseline total cortisol measurement to diagnose AI was 0.94 (95% CI, 0.81-0.98). The optimal cutoff was 485 nM(-1), providing a sensitivity and a specificity of 89% and 100%, respectively. Total baseline cortisol measurement is accurate and sufficient to diagnose AI in brain-dead patients, even if albumin or corticosteroid-binding globulin concentrations are low.