Estimation of body fat and lean tissue distribution by dual energy X-ray absorptiometry and abdominal body fat evaluation by computed tomography in Cushing's disease

Abnormal body composition in patients with adrenal adenomas

OBJECTIVE

Increased visceral fat and sarcopenia are cardiovascular risk factors that may explain increased cardiovascular morbidity and frailty in patients with adrenal adenomas. Our objective was to compare body composition measurement of patients with adrenal adenomas to referent subjects without adrenal disease.

DESIGN

Cross-sectional study, 2014-2018.

METHODS

Participants were adults with nonfunctioning adrenal tumor (NFAT), mild autonomous cortisol secretion (MACS), and Cushing syndrome (CS) and age, sex, and BMI 1:1 matched referent subjects without adrenal disorders. Main outcome measures were body composition measurements calculated from abdominal CT imaging. Intra-abdominal adipose tissue and muscle mass measurements were performed at the third lumbar spine level.

RESULTS

Of 227 patients with adrenal adenomas, 20 were diagnosed with CS, 76 with MACS, and 131 with NFAT. Median age was 56 years (range: 18-89), and 67% were women. When compared to referent subjects, patients with CS, MACS, and NFAT demonstrated a higher visceral fat (odds ratio (OR): 2.2 (95% CI: 0.9-6.5), 2.0 (1.3-3.2), and 1.8 (1.2-2.7) and a lower skeletal muscle area (OR: 0.01 (95% CI: 0-0.09), 0.31 (0.18-0.49), and 0.3 (1.2-2.7)) respectively. For every 1 µg/dL cortisol increase after overnight dexamethasone, visceral fat/muscle area ratio increased by 2.3 (P = 0.02) and mean total skeletal muscle area decreased by 2.2 cm2 (P = 0.03).

CONCLUSION

Patients with adrenal adenomas demonstrate a lower muscle mass and a higher proportion of visceral fat when compared to referent subjects, including patients with NFAT. Even a subtle abnormality in cortisol secretion may impact health of patients with adenomas.

HAND2 is a novel obesity-linked adipogenic transcription factor regulated by glucocorticoid signalling

AIMS/HYPOTHESIS

Adipocytes are critical cornerstones of energy metabolism. While obesity-induced adipocyte dysfunction is associated with insulin resistance and systemic metabolic disturbances, adipogenesis, the formation of new adipocytes and healthy adipose tissue expansion are associated with metabolic benefits. Understanding the molecular mechanisms governing adipogenesis is of great clinical potential to efficiently restore metabolic health in obesity. Here we investigate the role of heart and neural crest derivatives-expressed 2 (HAND2) in adipogenesis.

METHODS

Human white adipose tissue (WAT) was collected from two cross-sectional studies of 318 and 96 individuals. In vitro, for mechanistic experiments we used primary adipocytes from humans and mice as well as human multipotent adipose-derived stem (hMADS) cells. Gene silencing was performed using siRNA or genetic inactivation in primary adipocytes from loxP and or tamoxifen-inducible Cre-ERT2 mouse models with Cre-encoding mRNA or tamoxifen, respectively. Adipogenesis and adipocyte metabolism were measured by Oil Red O staining, quantitative PCR (qPCR), microarray, glucose uptake assay, western blot and lipolysis assay. A combinatorial RNA sequencing (RNAseq) and ChIP qPCR approach was used to identify target genes regulated by HAND2. In vivo, we created a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter (Hand2^AdipoqCre) and performed a large panel of metabolic tests.

RESULTS

We found that HAND2 is an obesity-linked white adipocyte transcription factor regulated by glucocorticoids that was necessary but insufficient for adipocyte differentiation in vitro. In a large cohort of humans, WAT HAND2 expression was correlated to BMI. The HAND2 gene was enriched in white adipocytes compared with brown, induced early in differentiation and responded to dexamethasone (DEX), a typical glucocorticoid receptor (GR, encoded by NR3C1) agonist. Silencing of NR3C1 in hMADS cells or deletion of GR in a transgenic conditional mouse model results in diminished HAND2 expression, establishing that adipocyte HAND2 is regulated by glucocorticoids via GR in vitro and in vivo. Furthermore, we identified gene clusters indirectly regulated by the GR-HAND2 pathway. Interestingly, silencing of HAND2 impaired adipocyte differentiation in hMADS and primary mouse adipocytes. However, a conditional adipocyte Hand2 deletion mouse model using Cre under control of the Adipoq promoter did not mirror these effects on adipose tissue differentiation, indicating that HAND2 was required at stages prior to Adipoq expression.

CONCLUSIONS/INTERPRETATION

In summary, our study identifies HAND2 as a novel obesity-linked adipocyte transcription factor, highlighting new mechanisms of GR-dependent adipogenesis in humans and mice.

DATA AVAILABILITY

Array data have been submitted to the GEO database at NCBI (GSE148699).

Imaging spectrum of abnormal subcutaneous and visceral fat distribution

Adipose tissue plays multiple and complex roles not only in mechanical cushioning and energy storage but also as an important secretory organ that regulates energy balance and homeostasis multilaterally. Fat tissue is categorized into subcutaneous fat tissue (SCAT) or visceral fat tissue (VSA) depending on its distribution, with the two having different metabolic functions. Near-total lack of fat in congenital/acquired generalized lipodystrophy, cachexia, or any other severe malnutrition condition induces severe multi-organ dysfunction due to lack of production of leptin and other adipokines. Increased visceral fat tissue secondary to obesity, hypercortisolism, or multiple symmetric lipomatosis raises the risk of insulin resistance, cardiac complications, and airway or spinal canal stenosis, although the fat distribution pattern differs in each condition. Partial abnormal fat distribution conditions such as HIV/HAART therapy-associated lipodystrophy, familial partial lipodystrophies, and acquired partial lipodystrophy frequently show a mixture of lipoatrophy and lipohypertrophy with metabolic dysfunction. Characteristic imaging features in conditions with local abnormal fat distribution can provide information about a patient’s co-existent/unrecognized disease(s), past medical history, or lifestyle. Knowledge of characteristic abnormal fat distribution patterns can contribute to proper and timely therapeutic decision-making and patient education.

Lipectomy associated to obesity produces greater fat accumulation in the visceral white adipose tissue of female compared to male rats

BACKGROUND

Mobility of fat deposited in adipocytes among different fatty territories can play a crucial role in the pathogenesis of obesity-related diseases. Our goal was to investigate which of the remaining fat pads assume the role of accumulating lipids after surgical removal of parietal WAT (lipectomy; LIPEC) in rats of both sexes displaying MSG-induced obesity.

METHODS

The animals entered the study straight after birth, being separated according to gender and randomly divided into CON (control, saline-treated) and MSG (monosodium glutamate-treated) groups. Next, the animals underwent LIPEC or sham-operated surgery (SHAM). Obesity was induced by the injection of MSG (4 mg/g/day) during neonatal stage (2nd to 11th day from birth). LIPEC was performed on the 12th week, consisting in the withdrawal of parietal WAT. On the 16th week, the following WATs were isolated and collected: peri-epididymal-WAT (EP-WAT); parametrial-WAT (PM-WAT); omental-WAT (OM-WAT); perirenal-WAT (PR-WAT) and retroperitoneal-WAT (RP-WAT).

RESULTS

The adiposity index was significantly increased in both male (3.2 ± 0.2** vs 1.8 ± 0.1) and female (4.9 ± 0.7* vs 2.6 ± 0.3) obese rats compared to their respective control groups. LIPEC in obese animals produced fat accumulation in visceral fat sites in a more accentuated manner in female (3.6 ± 0.3** vs 2.8 ± 0.3 g/100 g) rather than in male (1.8 ± 0.2* vs 1.5 ± 0.1 g/100 g) rats compared to obese non-lipectomized animals. Among the visceral WATs, the greater differences were observed between gonadal WATs of obese lipectomized rats, with higher accumulation having been observed in PM-WAT (2.8 ± 0.3* vs 2.1 ± 0.2 g/100 g) rather than in EP-WAT (1.0 ± 0.1 ± 0.9 ± 0.1 g/100 g) when compared to obese non-lipectomized animals.

CONCLUSIONS

The results of the present study led us to conclude that obesity induced by MSG treatment occurs differently in male and female rats. When associated with parietal LIPEC, there was a significant increase in the deposition of visceral fat, which was significantly higher in obese female rats than in males, indicating that fat mobility among WATs in lipectomized-obese rats can occur more expressively in particular sites of remaining WATs.

The relationship of mitochondrial dysfunction and the development of insulin resistance in Cushing's syndrome

PURPOSE

Cushing's syndrome is characterized by metabolic disturbances including insulin resistance. Mitochondrial dysfunction is one pathogenic factor in the development of insulin resistance in patients with obesity. We explored whether mitochondrial dysfunction correlates with insulin resistance and other metabolic complications.

PATIENTS AND METHODS

We investigated the changes of mRNA expression of genes encoding selected subunits of oxidative phosphorylation system (OXPHOS), pyruvate dehydrogenase (PDH) and citrate synthase (CS) in subcutaneous adipose tissue (SCAT) and peripheral monocytes (PM) and mitochondrial enzyme activity in platelets of 24 patients with active Cushing's syndrome and in 9 of them after successful treatment and 22 healthy control subjects.

RESULTS

Patients with active Cushing's syndrome had significantly increased body mass index (BMI), homeostasis model assessment of insulin resistance (HOMA-IR) and serum lipids relative to the control group. The expression of all investigated genes for selected mitochondrial proteins was decreased in SCAT in patients with active Cushing's syndrome and remained decreased after successful treatment. The expression of most tested genes in SCAT correlated inversely with BMI and HOMA-IR. The expression of genes encoding selected OXPHOS subunits and CS was increased in PM in patients with active Cushing's syndrome with a tendency to decrease toward normal levels after cure. Patients with active Cushing's syndrome showed increased enzyme activity of complex I (NQR) in platelets.

CONCLUSION

Mitochondrial function in SCAT in patients with Cushing's syndrome is impaired and only slightly affected by its treatment which may reflect ongoing metabolic disturbances even after successful treatment of Cushing's syndrome.

Glucocorticoid Receptor and Adipocyte Biology

Glucocorticoids are steroid hormones that play a key role in metabolic adaptations during stress, such as fasting and starvation, in order to maintain plasma glucose levels. Excess and chronic glucocorticoid exposure, however, causes metabolic syndrome including insulin resistance, dyslipidemia, and hyperglycemia. Studies in animal models of metabolic disorders frequently demonstrate that suppressing glucocorticoid signaling improves insulin sensitivity and metabolic profiles. Glucocorticoids convey their signals through an intracellular glucocorticoid receptor (GR), which is a transcriptional regulator. The adipocyte is one cell type that contributes to whole body metabolic homeostasis under the influence of GR. Glucocorticoids' functions on adipose tissues are complex. Depending on various physiological or pathophysiological states as well as distinct fat depots, glucocorticoids can either increase or decrease lipid storage in adipose tissues. In rodents, glucocorticoids have been shown to reduce the thermogenic activity of brown adipocytes. However, in human acute glucocorticoid exposure, glucocorticoids act to promote thermogenesis. In this article, we will review the recent studies on the mechanisms underlying the complex metabolic functions of GR in adipocytes. These include studies of the metabolic outcomes of adipocyte specific GR knockout mice and identification of novel GR primary target genes that mediate glucocorticoid action in adipocytes.

Impact of Adrenal Steroids on Regulation of Adipose Tissue

Corticosteroids are secreted by the adrenal glands and control the functions of adipose tissue via the activation of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR). In turn, adipocytes release a large variety of adipokines into the bloodstream, regulating the function of several organs and tissues, including the adrenal glands, hereby controlling corticosteroid production. In adipose tissue, the activation of the MR by glucocorticoids (GC) and aldosterone affects important processes such as adipocyte differentiation, oxidative stress, autophagic flux, adipokine expression as well as local production of GC through upregulation of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Notably, the proinflammatory responses induced by the MR are counteracted by activation of the GR, whose activity inhibits the expression of inflammatory adipokines. Both GR and MR are deeply involved in adipogenesis and adipose expansion; hence pharmacological blockade of these two receptors has proven effective against adipose tissue dysfunction in experimental models of obesity and metabolic syndrome (MetS), suggesting a potential use for MR and GR antagonists in these clinical settings. Importantly, obesity and Cushing's syndrome (CS) share metabolic similarities and are characterized by high levels of circulating corticosteroids, which in turn are able to deeply affect adipose tissue. In addition, pharmacological approaches aimed at reducing aldosterone and GC levels, by means of the inhibition of CYP11B2 (aldosterone synthase) or 11β-HSD1, represent alternative strategies to counter the detrimental effects of excessive levels of corticosteroids, which are often observed in obesity and, more general, in MetS. © 2017 American Physiological Society. Compr Physiol 7:1425-1447, 2017.

Acute Hypercortisolemia Exerts Depot-Specific Effects on Abdominal and Femoral Adipose Tissue Function

CONTEXT

Glucocorticoids have pleiotropic metabolic functions, and acute glucocorticoid excess affects fatty acid metabolism, increasing systemic lipolysis. Whether glucocorticoids exert adipose tissue depot-specific effects remains unclear.

OBJECTIVE

To provide an in vivo assessment of femoral and abdominal adipose tissue responses to acute glucocorticoid administration.

DESIGN AND OUTCOME MEASURES

Nine healthy male volunteers were studied on two occasions, after a hydrocortisone infusion (0.2 mg/kg/min for 14 hours) and a saline infusion, respectively, given in randomized double-blind order. The subjects were studied in the fasting state and after a 75-g glucose drink with an in vivo assessment of femoral adipose tissue blood flow (ATBF) using radioactive xenon washout and of lipolysis and glucose uptake using the arteriovenous difference technique. In a separate study (same infusion design), eight additional healthy male subjects underwent assessment of fasting abdominal ATBF and lipolysis only. Lipolysis was assessed as the net release of nonesterified fatty acids (NEFAs) from femoral and abdominal subcutaneous adipose tissue.

RESULTS

Acute hypercortisolemia significantly increased basal and postprandial ATBF in femoral adipose tissue, but the femoral net NEFA release did not change. In abdominal adipose tissue, hypercortisolemia induced substantial increases in basal ATBF and NEFA release.

CONCLUSIONS

Acute hypercortisolemia induces differential lipolysis and ATBF responses in abdominal and femoral adipose tissue, suggesting depot-specific glucocorticoid effects. Abdominal, but not femoral, adipose tissue contributes to the hypercortisolemia-induced systemic NEFA increase, with likely contributions from other adipose tissue sources and intravascular triglyceride hydrolysis.

Muscle-specific downregulation of GR levels inhibits adipogenesis in porcine intramuscular adipocyte tissue

Intramuscular adipose is conducive to good pork quality, whereas subcutaneous adipose is considered as waste in pig production. So uncovering the regulation differences between these two adiposes is helpful to tissue-specific control of fat deposition. In this study, we found the sensitivity to glucocorticoids (GCs) was lower in intramuscular adipocytes (IMA) compared with subcutaneous adipocytes (SA). Comparison of glucocorticoid receptor (GR) revealed that IMA had lower GR level which contributed to its reduced GCs sensitivity. Higher methylation levels of GR promotor 1-C and 1-H were detected in IMA compared with SA. GR expression decrease was also found in adipocytes when treated with muscle conditioned medium (MCM) in vitro, which resulted in significant inhibition of adipocytes proliferation and differentiation. Since abundant myostatin (MSTN) was detected in MCM by ELISA assay, we further investigated the effect of this myokine on adipocytes. MSTN treatment suppressed adipocytes GR expression, cell proliferation and differentiation, which mimicked the effects of MCM. The methylation levels of GR promotor 1-C and 1-H were also elevated after MSTN treatment. Our study reveals the role of GR in muscle fiber inhibition on intramuscular adipocytes, and identifies myostatin as a muscle-derived modulator for adipose GR level.

Depot Dependent Effects of Dexamethasone on Gene Expression in Human Omental and Abdominal Subcutaneous Adipose Tissues from Obese Women

Glucocorticoids promote fat accumulation in visceral compared to subcutaneous depots, but the molecular mechanisms involved remain poorly understood. To identify long-term changes in gene expression that are differentially sensitive or responsive to glucocorticoids in these depots, paired samples of human omental (Om) and abdominal subcutaneous (Abdsc) adipose tissues obtained from obese women during elective surgery were cultured with the glucocorticoid receptor agonist dexamethasone (Dex, 0, 1, 10, 25 and 1000 nM) for 7 days. Dex regulated 32% of the 19,741 genes on the array, while 53% differed by Depot and 2.5% exhibited a Depot*Dex concentration interaction. Gene set enrichment analysis showed Dex regulation of the expected metabolic and inflammatory pathways in both depots. Cluster analysis of the 460 transcripts that exhibited an interaction of Depot and Dex concentration revealed sets of mRNAs for which the responses to Dex differed in magnitude, sensitivity or direction between the two depots as well as mRNAs that responded to Dex only in one depot. These transcripts were also clearly depot different in fresh adipose tissue and are implicated in processes that could affect adipose tissue distribution or functions (e.g. adipogenesis, triacylglycerol synthesis and storage, insulin action). Elucidation of the mechanisms underlying the depot differences in the effect of Dex on the expression of specific genes and pathways that regulate adipose function may offer novel insights into understanding the biology of visceral adipose tissues and their links to metabolic health.

A prospective study of appetite and food craving in 30 patients with Cushing's disease

CONTEXT

Glucocorticoid (GC) exposure increases food intake, but the mechanisms in humans are not known. Investigation of appetite and food craving has not been done in patients with chronic GC exposure due to Cushing's disease (CD), either before or after treatment, and could provide insight into mechanisms of food intake and obesity in these patients.

PURPOSE

To examine whether surgical remission of CD changes appetite (prospective consumption, hunger, satisfaction, and fullness) and food cravings (sweet, salty, fatty, and savory); and to identify predictors of appetite and craving in CD remission.

METHODS

30 CD patients, mean age 40.0 years (range 17-70), mean BMI 32.3 ± 6.4, were prospectively studied before and at a mean of 17.4 mo. after remission. At each visit fasting and post-test meal (50% carbohydrate, 35% protein, 15% fat) appetite and craving scores were assessed.

RESULTS

Remission decreased prospective consumption, sweet and savory craving (p < 0.05), but did not change hunger, satisfaction, fullness, or fat craving, despite decreases in BMI and fat mass. In CD remission, serum cortisol predicted lower satisfaction and fullness, and masses of abdominal fat depots predicted higher hunger and consumption (p < 0.05).

CONCLUSIONS

Chronic GC exposure in CD patients may stimulate the drive to eat by enhancing craving, rather than regulating the sensation of hunger. Continued alterations in appetite regulation due to abdominal fat mass and circulating cortisol could play a role in the cardiovascular and metabolic risk that has been reported in CD patients despite remission.

Impact of long-term steroid therapy on epicardial and pericardial fat deposition: a cardiac MRI study

BACKGROUND

Increased cardiac fat has been identified as a risk factor for coronary artery disease. Metabolic syndrome is associated with increased cardiac fat deposition. Steroids are known to imitate some effects of metabolic syndrome and are frequently used in patients with rheumatic disorders. Primary aim was to evaluate the impact of long-term steroid use on cardiac fat deposition in patients with rheumatic disorders. In addition, we sought to investigate if this effect might be dose-dependent.

METHODS

Patients were enrolled as follows: (1) rheumatic disorder; and (2) long-term steroid therapy, and (3) underwent cardiovascular magnetic resonance (CMR) imaging. Patients were stratified in a high-dose (>7.5 mg prednisone equivalent/day for at least 6 months) and a low-dose steroid group (<7.5 mg prednisone equivalent/day) and compared to steroid-naïve controls without rheumatic disorders.

RESULTS

122 patients were included (n = 61 steroid patients, n = 61 controls). N = 36 were classified as high-dose, n = 25 as low-dose steroid group. Steroid patients showed larger epicardial 5.7 [3.5-9.1] cm(2) and pericardial 13.0 [6.1-26.8] cm(2) areas of fat than controls 4.2 [1.3-5.8] cm(2)/6.4 [1.6-15.4] cm(2), p < 0.001, p < 0.01, respectively. High-dose steroid patients had more epi- and pericardial fat both than controls: 7.2 [4.2-11.1] cm(2) vs. 4.4 [1.0-6.0] cm(2), p < 0.001; 18.6 [8.9-38.2] cm(2) vs. 10.7 [4.7-26.8] cm(2), p < 0.05, and patients in the low-dose steroid group (p < 0.01, p < 0.001, respectively).

CONCLUSION

The present data suggest increased cardiac fat deposition in steroid-treated patients with rheumatic disorders. Furthermore, this accumulation of cardiac fat seems to be dose-dependent, pointing towards a cumulative effect of steroids.

Cortisol Measures Across the Weight Spectrum

CONTEXT

There are conflicting reports of increased vs decreased hypothalamic-pituitary-adrenal (HPA) activation in obesity; the most consistent finding is an inverse relationship between body mass index (BMI) and morning cortisol. In anorexia nervosa (AN), a low-BMI state, cortisol measures are elevated.

OBJECTIVE

This study aimed to investigate cortisol measures across the weight spectrum.

DESIGN AND SETTING

This was a cross-sectional study at a clinical research center.

PARTICIPANTS

This study included 60 women, 18-45 years of age: overweight/obese (OB; N = 21); AN (N = 18); and normal-weight controls (HC; N = 21).

MEASURES

HPA dynamics were assessed by urinary free cortisol, mean overnight serum cortisol obtained by pooled frequent sampling every 20 minutes from 2000-0800 h, 0800 h serum cortisol and cortisol-binding globulin, morning and late-night salivary cortisol, and dexamethasone-CRH testing. Body composition and bone mineral density (BMD) were assessed by dual-energy x-ray absorptiometry.

RESULTS

Cortisol measures demonstrated a U-shaped relationship with BMI, nadiring in the overweight-class I obese range, and were similarly associated with visceral adipose tissue and total fat mass. Mean cortisol levels were higher in AN than OB. There were weak negative linear relationships between lean mass and some cortisol measures. Most cortisol measures were negatively associated with postero-anterior spine and total hip BMD.

CONCLUSIONS

Cortisol measures are lowest in overweight-class I obese women-lower than in lean women. With more significant obesity, cortisol levels increase, although not to as high as in AN. Therefore, extreme underweight and overweight states may activate the HPA axis, and hypercortisolemia may contribute to increased adiposity in the setting of caloric excess. Hypercortisolemia may also contribute to decreased BMD and muscle wasting in the setting of both caloric restriction and excess.

Body composition, hemodynamic, and biochemical parameters of young female normal-weight oligo-amenorrheic and eumenorrheic athletes and nonathletes

AIMS

Low-weight hypogonadal conditions such as anorexia nervosa are associated with marked changes in body composition, hemodynamic and hematological parameters, and liver enzymes. The impact of athletic activity in normal-weight adolescents with/without amenorrhea on these parameters has not been assessed. Our aim was to examine these parameters in normal-weight athletes and nonathletes and determine any associations with body composition, oligo-amenorrhea, and exercise intensity.

METHODS

We assessed vital signs, complete blood counts, liver enzymes, and regional body composition in 43 oligo-amenorrheic athletes (OAA), 24 eumenorrheic athletes (EA), and 23 nonathletes aged 14-21 years.

RESULTS

The BMI was lower in OAA than in EA. Systolic and pulse pressure and temperature were lowest in OAA. Blood counts did not differ among groups. Aspartate aminotransferase (AST) was higher in both groups of athletes, while alanine aminotransferase (ALT) was higher in OAA than in EA and nonathletes. Total and regional fat were lower in OAA than in other groups, and these factors were associated positively with heart rate and inversely with liver enzymes.

CONCLUSIONS

Athletic activity is associated with higher AST levels, whereas menstrual dysfunction is associated with lower total and regional fat and higher ALT levels. Higher liver enzymes are associated with reductions in total and regional fat.

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.

Inhalational Steroids and Iatrogenic Cushing's Syndrome

Bronchial asthma (BA) and Allergic rhinitis (AR) are common clinical problems encountered in day to day practice, where inhalational corticosteroids (ICS) or intranasal steroids (INS) are the mainstay of treatment. Iatrogenic Cushing syndrome (CS) is a well known complication of systemic steroid administration. ICS /INS were earlier thought to be safe, but now more and more number of case reports of Iatrogenic Cushing syndrome have been reported, especially in those who are taking cytochrome P450 (CYP 450) inhibitors. Comparing to the classical clinical features of spontaneous Cushing syndrome, iatrogenic Cushing syndrome is more commonly associated with osteoporosis, increase in intra-ocular pressure, benign intracranial hypertension, aseptic necrosis of femoral head and pancreatitis, where as hypertension, hirsuitisum and menstrual irregularities are less common. Endocrine work up shows low serum cortisol level with evidence of HPA (hypothalamo-pituitary-adrenal) axis suppression. In all patients with features of Cushing syndrome with evidence of adrenal suppression always suspect iatrogenic CS. Since concomitant administration of cytochrome P450 inhibitors in patients on ICS/INS can precipitate iatrogenic CS, avoidance of CYP450 inhibitors, its dose reduction or substitution of ICS are the available options. Along with those, measures to prevent the precipitation of adrenal crisis has to be taken. An update on ICS-/INS- associated iatrogenic CS and its management is presented here.

Quality of life and other outcomes in children treated for Cushing syndrome

CONTEXT

Cushing syndrome (CS) in children is associated with residual impairment in measures of health-related quality of life, even after successful resolution of hypercortisolemia, highlighting the need for early identification of morbidities and improvements in long-term management of these patients.

EVIDENCE ACQUISITION AND SYNTHESIS

A PubMed, Scopus, and Web of Science search of articles from 1900 onward identified available studies related to quality of life and complications of pediatric CS as well as important historical articles. This review summarizes studies through November 2012 and highlights recent developments.

CONCLUSIONS

A review of the literature identifies significant morbidities associated with CS of pediatric onset, which must not be treated in isolation. CS affects children and adolescents in many ways that are different than adults. Post-treatment challenges for the child or adolescent treated for CS include: optimize growth and pubertal development, normalize body composition, and promote psychological health and cognitive maturation. All these factors impact health-related quality of life, which is an important outcome measure to assess the burden of disease as well as the effect of treatment. Future research efforts are needed to improve management of the physical, psychological, and emotional aspects of this disease in order to diminish the residual impairments experienced by the pediatric CS patient population.

Deconstructing the roles of glucocorticoids in adipose tissue biology and the development of central obesity

Central obesity is associated with insulin resistance and dyslipidemia. Thus, the mechanisms that control fat distribution and its impact on systemic metabolism have importance for understanding the risk for diabetes and cardiovascular disease. Hypercortisolemia at the systemic (Cushing's syndrome) or local levels (due to adipose-specific overproduction via 11β-hydroxysteroid dehydrogenase 1) results in the preferential expansion of central, especially visceral fat depots. At the same time, peripheral subcutaneous depots can become depleted. The biochemical and molecular mechanisms underlying the depot-specific actions of glucocorticoids (GCs) on adipose tissue function remain poorly understood. GCs exert pleiotropic effects on adipocyte metabolic, endocrine and immune functions, and dampen adipose tissue inflammation. GCs also regulate multiple steps in the process of adipogenesis. Acting synergistically with insulin, GCs increase the expression of numerous genes involved in fat deposition. Variable effects of GC on lipolysis are reported, and GC can improve or impair insulin action depending on the experimental conditions. Thus, the net effect of GC on fat storage appears to depend on the physiologic context. The preferential effects of GC on visceral adipose tissue have been linked to higher cortisol production and glucocorticoid receptor expression, but the molecular details of the depot-dependent actions of GCs are only beginning to be understood. In addition, increasing evidence underlines the importance of circadian variations in GCs in relationship to the timing of meals for determining their anabolic actions on the adipocyte. In summary, although the molecular mechanisms remain to be fully elucidated, there is increasing evidence that GCs have multiple, depot-dependent effects on adipocyte gene expression and metabolism that promote central fat deposition. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

Impact of mifepristone, a glucocorticoid/progesterone antagonist, on HDL cholesterol, HDL particle concentration, and HDL function

CONTEXT

Mifepristone is a glucocorticoid and progestin antagonist under investigation for the treatment of Cushing's syndrome. Mifepristone decreases high-density lipoprotein (HDL) cholesterol (HDL-C) levels in treated patients, but the clinical significance of this is unclear because recent studies suggest that functional properties of HDL predict cardiovascular disease status better than does HDL-C concentration.

OBJECTIVE

The aim of the study was to characterize the impact of mifepristone administration on HDL particle concentration and function.

DESIGN AND SETTING

We conducted a double-blind, randomized, placebo-controlled trial at a single-site, clinical research center.

PARTICIPANTS

Thirty healthy postmenopausal female volunteers participated in the study.

INTERVENTION

Individuals were randomized to receive daily oral mifepristone (600 mg) or placebo for 6 wk.

MAIN OUTCOME MEASURES

We measured HDL-C, serum HDL particle concentration, and HDL-mediated cholesterol efflux by treatment group.

RESULTS

As expected, ACTH, cortisol, estradiol, and testosterone levels increased in the mifepristone group. Mifepristone treatment decreased HDL-C and HDL particle concentration by 26 and 25%, respectively, but did not alter pre-β HDL concentration. In contrast, the serum HDL-mediated cholesterol efflux decreased with mifepristone treatment by only 12%, resulting in an effective increase of the efflux capacity per HDL particle. No changes were observed in cholesterol ester transfer protein or lecithin:cholesterol acyltransferase activity.

CONCLUSIONS

Treatment with mifepristone reduced HDL-C, HDL particle concentration, and serum HDL cholesterol efflux in postmenopausal women. However, on a per particle basis, the efflux capacity of serum HDL increased. These observations support the concept that a decrease in HDL-C may not represent proportional impairment of HDL function.

Body composition and cardiovascular risk markers after remission of Cushing's disease: a prospective study using whole-body MRI

CONTEXT

Cushing's Disease (CD) alters fat distribution, muscle mass, adipokine profile, and cardiovascular risk factors. It is not known whether remission entirely reverses these changes.

OBJECTIVES

Our objective was to determine whether the adverse body composition and cardiovascular risk profile in CD change after remission.

DESIGN, SETTING, AND PATIENTS

Fourteen CD patients were studied prospectively: before surgery (active disease) and again postoperatively 6 months after discontinuing oral glucocorticoids (remission). Whole-body magnetic resonance imaging was used to examine lean and fat tissue distributions.

OUTCOME MEASURES

Body composition (skeletal muscle and fat in the visceral, bone marrow, sc, and inter-muscular compartments) and cardiovascular risk factors (serum insulin, glucose, leptin, high-molecular-weight adiponectin, C-reactive protein, and lipid profile) were measured in active CD and remission (mean 20 months after surgery).

RESULTS

Remission decreased visceral, pelvic bone marrow, sc (including trunk and limb sc), and total fat; waist circumference; and weight (P < 0.05). Remission altered fat distribution, resulting in decreased visceral/total fat (P = 0.04) and visceral fat/skeletal muscle ratios (P = 0.006). Remission decreased the absolute muscle mass (P = 0.015). Cardiovascular risk factors changed: insulin resistance, leptin, and total cholesterol decreased (P < 0.05), but adiponectin, C-reactive protein, and other lipid measures did not change.

CONCLUSIONS

CD remission reduced nearly all fat depots and reverted fat to a distribution more consistent with favorable cardiovascular risk but decreased skeletal muscle. Remission improved some but not all cardiovascular risk markers. Remission from CD dramatically improves body composition abnormalities but may still be associated with persistent cardiovascular risk.

Plasma kinetics of an LDL-like nanoemulsion and lipid transfer to HDL in subjects with glucose intolerance

OBJECTIVE

Glucose intolerance is frequently associated with an altered plasma lipid profile and increased cardiovascular disease risk. Nonetheless, lipid metabolism is scarcely studied in normolipidemic glucose-intolerant patients. The aim of this study was to investigate whether important lipid metabolic parameters, such as the kinetics of LDL free and esterified cholesterol and the transfer of lipids to HDL, are altered in glucose-intolerant patients with normal plasma lipids.

METHODS

Fourteen glucose-intolerant patients and 15 control patients were studied; none of the patients had cardiovascular disease manifestations, and they were paired for age, sex, race and co-morbidities. A nanoemulsion resembling a LDL lipid composition (LDE) labeled with 14C-cholesteryl ester and ³H-free cholesterol was intravenously injected, and blood samples were collected over a 24-h period to determine the fractional clearance rate of the labels by compartmental analysis. The transfer of free and esterified cholesterol, triglycerides and phospholipids from the LDE to HDL was measured by the incubation of the LDE with plasma and radioactivity counting of the supernatant after chemical precipitation of non-HDL fractions.

RESULTS

The levels of LDL, non-HDL and HDL cholesterol, triglycerides, apo A1 and apo B were equal in both groups. The 14C-esterified cholesterol fractional clearance rate was not different between glucose-intolerant and control patients, but the ³H-free-cholesterol fractional clearance rate was greater in glucose-intolerant patients than in control patients. The lipid transfer to HDL was equal in both groups.

CONCLUSION

In these glucose-intolerant patients with normal plasma lipids, a faster removal of LDE free cholesterol was the only lipid metabolic alteration detected in our study. This finding suggests that the dissociation of free cholesterol from lipoprotein particles occurs in normolipidemic glucose intolerance and may participate in atherogenic signaling.

Chronic stress, energy balance and adiposity in female rats

Stress preferentially increases the consumption of high fat foods in women, suggesting the interaction of these two factors may disproportionately predispose women toward excess weight gain. In the present study, female rats were exposed to a chronic high fat or chow diet and were exposed to 4weeks of chronic variable stress (CVS) or served as home cage controls. Control females exposed to a high fat diet displayed many symptoms of the metabolic syndrome including increased body weight gain, total and visceral adiposity and insulin and leptin concentrations relative to all groups. However, CVS-high fat, CVS chow and control chow groups had similar body weight gain and caloric efficiency. This finding suggests that CVS increases energy expenditure much more in females exposed to a high fat diet relative to those fed a standard chow diet. The CVS-high fat group had increased adiposity and increased circulating leptin and insulin concentrations, despite the fact that their body weight did not differ from the controls. These results underscore the importance of assessing the degree of adiposity, rather than body weight alone, as an index of overall metabolic health. Overall, the data indicate that in female rats, chronic stress prevents high fat diet related increases in body weight, but does not prevent high fat diet induced increases in adiposity when compared to chow-fed females.

Decreased glucose tolerance and plasma adiponectin:resistin ratio in a mouse model of post-traumatic stress disorder

AIMS/HYPOTHESIS

Obesity and type 2 diabetes are among the most serious health pathologies worldwide. Stress has been proposed as a factor contributing to the development of these health risk factors; however, the underlying mechanisms that link stress to obesity and diabetes need to be further clarified. Here, we study in mice how chronic stress affects dietary consumption and how that relationship contributes to obesity and diabetes.

METHODS

C57BL/6J mice were subjected to chronic variable stress (CVS) for 15 days and subsequently fed with a standard chow or high-fat diet. Food intake, body weight, respiratory quotient, energy expenditure and spontaneous physical activity were measured with a customised calorimetric system and body composition was measured with nuclear magnetic resonance. A glucose tolerance test was also applied and blood glucose levels were measured with a glucometer. Plasma levels of adiponectin and resistin were measured using Lincoplex kits.

RESULTS

Mice under CVS and fed with a high-fat diet showed impaired glucose tolerance associated with low plasma adiponectin:resistin ratios.

CONCLUSIONS/INTERPRETATION

This study demonstrates, in a novel mouse model, how post-traumatic stress disorder enhances vulnerability for impaired glucose metabolism in an energy-rich environment and proposes a potential adipokine-based mechanism.

MRI assessment of lean and adipose tissue distribution in female patients with Cushing's disease

OBJECTIVE

Chronic hypercortisolemia due to Cushing's disease (CD) results in abnormal adipose tissue (AT) distribution. Whole-body magnetic resonance imaging (MRI) was used to examine lean and AT distribution in female patients with CD to further understand the role of glucocorticoid excess in the development of abnormal AT distribution and obesity.

DESIGN

Cross-sectional and case-control study.

PATIENTS

Fifteen women with CD and 12 healthy controls.

MEASUREMENTS

Mass of skeletal muscle (SM) and AT in the visceral (VAT), subcutaneous (SAT), and intermuscular (IMAT) compartments from whole-body MRI and serum levels of insulin, glucose, and leptin were measured.

RESULTS

CD patients had leptin values that correlated to total AT (TAT) and SAT (P < 0.05) but not to VAT. CD patients had higher VAT/TAT ratios (P < 0.01) and lower SAT/TAT ratios (P < 0.05) compared to controls. TAT, VAT, and trunk SAT (TrSAT) were greater in CD patients (P < 0.01). SM was less in CD (P < 0.001) but IMAT was not different.

CONCLUSIONS

TAT, VAT, trSAT, and the proportion of AT in the visceral depot were greater in CD although the proportion in the subcutaneous depot was less. SM was less but IMAT was not different. These findings have implications for understanding the role of cortisol in the abnormal AT distribution and metabolic risk seen in patients exposed to chronic excess glucocorticoids.

Short-term prednisone use antagonizes insulin's anabolic effect on muscle protein and glucose metabolism in young healthy people

Glucocorticoids cause muscle atrophy and weakness, but the mechanisms for these effects are unclear. The purpose of this study was to test a hypothesis that prednisone (Pred) counteracts insulin's anabolic effects on muscle. A randomized, double-blind cross-over design was used to test the effects of 6 days either Pred (0.8 mg x kg(-1) x day(-1)) or placebo use in seven healthy young volunteers. Protein dynamics were measured across the leg using stable isotope tracers of leucine (Leu) and phenylalanine (Phe) after overnight fast and during a hyperinsulinemic (1.5 microU x min(-1) x kg FFM(-1)) euglycemic clamp with amino acid replacement. Fasting glucose, amino acids, insulin, and glucagon were higher (P < 0.01) on Pred vs. placebo, whereas leg blood flow was 18% lower. However, basal whole body and leg kinetics of Leu and Phe were unaltered by Pred. Insulin infusion increased leg glucose uptake in both trials but was 65% lower with Pred than with placebo. Insulin in both trials similarly suppressed whole body flux of Leu and Phe. Importantly, insulin increased net Leu and Phe balance across the leg and the balance between muscle protein synthesis and breakdown, but these changes were 45-140% lower (P < 0.03) in Pred than in placebo. The present study demonstrates that short-term Pred use in healthy people does not alter whole body or leg muscle protein metabolism during the postaborptive state but causes muscle insulin resistance for both glucose and amino acid metabolism, with a blunted protein anabolism. This interactive effect may lead to muscle atrophy with continued use of glucocorticoids.

The pituitary-adrenal axis and body composition

The activity of the pituitary-adrenal axis can profoundly impact on body composition. This is dramatically seen in Cushing's syndrome (CS) but changes in body composition are also implicated in depression and alcoholic pseudocushing's. The pathophysiological mechanisms underlying these changes remain poorly understood. Changes to body composition in CS include increased fat mass, decreased bone mass, thinning of the skin and reduced lean mass. Why these tissues are affected so dramatically is unclear. Additionally, the change in body composition between individuals varies considerably for reasons which are only now becoming evident. This paper reviews the phenotypic changes with altered pituitary-adrenal axis activity and discusses the mechanisms involved. The primary focus is on adipose, bone, muscle and skin since the most dramatic changes are seen in these tissues.

Lack of association between glucocorticoid use and presence of the metabolic syndrome in patients with rheumatoid arthritis: a cross-sectional study

Introduction

Rheumatoid arthritis (RA) associates with excessive cardiovascular morbidity and mortality, attributed to both traditional and novel cardiovascular risk factors. The metabolic syndrome, a cluster of classical cardiovascular risk factors, including hypertension, obesity, glucose intolerance, and dyslipidaemia, is highly prevalent in RA. Reports suggest that long-term glucocorticoid (GC) use may exacerbate individual cardiovascular risk factors, but there have been no studies in RA to assess whether it associates with the metabolic syndrome. We examined whether GC exposure associates with the presence of metabolic syndrome in patients with RA.

Methods

RA patients (n = 398) with detailed clinical and laboratory assessments were categorised into three groups according to GC exposure: no/limited (<3 months) exposure (NE), low-dose (<7.5 mg/day) long-term exposure (LE), and medium-dose (greater than or equal to 7.5 mg to 30 mg/day) long-term exposure (ME). The metabolic syndrome was defined using the National Cholesterol Education Programme III guidelines. The association of GC exposure with the metabolic syndrome was evaluated using binary logistic regression.

Results

The metabolic syndrome was present in 40.1% of this population and its prevalence did not differ significantly between the GC exposure groups (NE 37.9% versus LE 40.7% versus ME 50%, P = 0.241). Binary logistic regression did not demonstrate any increased odds for the metabolic syndrome when comparing ME with LE (odds ratio = 1.64, 95% confidence interval 0.92 to 2.92, P = 0.094) and remained non significant after adjusting for multiple potential confounders.

Conclusions

Long-term GC exposure does not appear to associate with a higher prevalence of the metabolic syndrome in patients with RA. The components of the metabolic syndrome may already be extensively modified by other processes in RA (including chronic inflammation and treatments other than GCs), leaving little scope for additive effects of GCs.

Protein metabolism in glucocorticoid excess: study in Cushing's syndrome and the effect of treatment

How protein metabolism is perturbed during chronic glucocorticoid excess is poorly understood. The aims were to investigate the impact of chronic glucocorticoid excess and restoration of eucortisolemia in Cushing's syndrome (CS) on whole body protein metabolism. Eighteen subjects with CS and 18 normal subjects (NS) underwent assessment of body composition using DEXA and whole body protein turnover with a 3-h constant infusion of l-[(13)C]leucine, allowing calculation of rates of leucine appearance (leucine R(a)), leucine oxidation (L(ox)), and leucine incorporation into protein (LIP). Ten subjects with CS were restudied after restoration of eucortisolemia. Percentage FM was greater (43.9 +/- 1.6 vs. 33.8 +/- 2.4%, P = 0.002) and LBM lower (52.7 +/- 1.6 vs. 62.1 +/- 2.3%, P = 0.002) in CS. LBM was significantly correlated (r(2) > 0.44, P < 0.005) to leuceine R(a), L(ox), and LIP in both groups. After correcting for LBM, leucine R(a) (133 +/- 5 vs. 116 +/- 5 micromol/min, P = 0.02) and L(ox) (29 +/- 1 vs. 24 +/- 1 micromol/min, P = 0.01) were greater in CS. FM significantly correlated (r(2) = 0.23, P < 0.05) with leucine R(a) and LIP, but not L(ox) in CS. In multiple regression, LBM was an independent determinant of all three indexes of leucine turnover, FM of leucine R(a), and LIP and CS of L(ox). Following restoration of eucortisolemia, L(ox) was reduced (Delta-7.5 +/- 2.6 micromol/min, P = 0.02) and LIP increased (Delta+15.2 +/- 6.2 micromol/min, P = 0.04). In summary, whole body protein metabolism in CS is influenced by changes in body composition and glucocorticoid excess per se, which increases protein oxidation. Enhanced protein oxidation is a likely explanation for the reduced protein mass in CS. Successful treatment of CS reduces protein oxidation and increases protein synthesis to prevent ongoing protein loss.

Body composition and vertebral fracture risk in female patients treated with glucocorticoid

INTRODUCTION

Glucocorticoid (GC) causes bone loss and an increase in bone fragility. However, fracture risk was found to be only partly explained by bone mineral density in GC-treated patients (GC patients). Although GC causes a change in the distribution of fat in the body, the relationship between body composition and fracture risk in GC patients remains unknown.

METHODS

The present study examined the relationship between the presence or absence of vertebral fractures and various indices, including body composition, in 92 premenopausal GC patients, 122 postmenopausal GC patients and 122 postmenopausal age-matched control subjects. Dual-energy X-ray absorptiometry was employed to analyze body composition.

RESULTS

Percentage lean body mass (LBM), % fat and % trunk fat were not significantly different between postmenopausal GC patients and the control women. When groups with and without vertebral fractures were compared, % LBM and % fat were significantly higher and lower in groups with vertebral fractures, respectively, in postmenopausal GC patients, but not in the postmenopausal control women, although % trunk fat was not significantly different between groups with and without vertebral fractures. Femoral neck BMD was negatively correlated with % LBM and positively correlated with % fat. In premenopausal GC patients, % trunk fat was significantly higher in the fracture group, although % LBM and % fat were not significantly different between groups with and without vertebral fractures.

CONCLUSION

The present study revealed that body composition is related to vertebral fracture risk in GC-treated patients. Lower % fat can be included in the determination of vertebral fractures in postmenopausal GC-treated patients. The influence of body composition on vertebral fracture risk may be different between the pre- and postmenopausal state in GC patients.

Enhanced circadian ACTH release in obese premenopausal women: reversal by short-term acipimox treatment

Several studies suggest that the hypothalamo-pituitary-adrenal (HPA) axis is exceedingly active in obese individuals. Experimental studies show that circulating free fatty acids (FFAs) promote the secretory activity of the HPA axis and that human obesity is associated with high circulating FFAs. We hypothesized that HPA axis activity is enhanced and that lowering of circulating FFAs by acipimox would reduce spontaneous secretion of the HPA hormonal ensemble in obese humans. To evaluate these hypotheses, diurnal ACTH and cortisol secretion was studied in 11 obese and 9 lean premenopausal women (body mass index: obese 33.5 +/- 0.9 vs. lean 21.2 +/- 0.6 kg/m(2), P < 0.001) in the early follicular stage of their menstrual cycle. Obese women were randomly assigned to treatment with either acipimox (inhibitor of lipolysis, 250 mg orally four times daily) or placebo in a double-blind crossover design, starting one day before admission until the end of the blood-sampling period. Blood samples were taken during 24 h with a sampling interval of 10 min for assessment of plasma ACTH and cortisol concentrations. ACTH and cortisol secretion rates were estimated by multiparameter deconvolution analysis. Daily ACTH secretion was substantially higher in obese than in lean women (7,950 +/- 1,212 vs. 2,808 +/- 329 ng/24 h, P = 0.002), whereas cortisol was not altered (obese 36,362 +/- 5,639 vs. lean 37,187 +/- 4,239 nmol/24 h, P = 0.912). Acipimox significantly reduced ACTH secretion in the obese subjects (acipimox 5,850 +/- 769 ng/24 h, P = 0.039 vs. placebo), whereas cortisol release did not change (acipimox 33,542 +/- 3,436 nmol/24 h, P = 0.484 vs. placebo). In conclusion, spontaneous ACTH secretion is enhanced in obese premenopausal women, whereas cortisol production is normal. Reduction of circulating FFA concentrations by acipimox blunts ACTH release in obese women, which suggests that FFAs are involved in the pathophysiology of this neuroendocrine anomaly.

Adipose tissue quantification by imaging methods: a proposed classification

Recent advances in imaging techniques and understanding of differences in the molecular biology of adipose tissue has rendered classical anatomy obsolete, requiring a new classification of the topography of adipose tissue. Adipose tissue is one of the largest body compartments, yet a classification that defines specific adipose tissue depots based on their anatomic location and related functions is lacking. The absence of an accepted taxonomy poses problems for investigators studying adipose tissue topography and its functional correlates. The aim of this review was to critically examine the literature on imaging of whole body and regional adipose tissue and to create the first systematic classification of adipose tissue topography. Adipose tissue terminology was examined in over 100 original publications. Our analysis revealed inconsistencies in the use of specific definitions, especially for the compartment termed "visceral" adipose tissue. This analysis leads us to propose an updated classification of total body and regional adipose tissue, providing a well-defined basis for correlating imaging studies of specific adipose tissue depots with molecular processes.

Leptin levels in relation to body composition and insulin concentration in patients with endogenous Cushing's syndrome compared to controls matched for body mass index

Cushing's syndrome (CS) is associated with weight gain and visceral obesity. We examined the relationship between regional fat distribution and serum levels of leptin, cortisol and insulin. Twenty-three consecutive patients with recently diagnosed CS (18 with pituitary adenoma, 5 with adrenal tumor), where compared to obese controls, matched for age, sex and Body Mass Index (BMI). Serum insulin, leptin, cortisol, C-peptide and body composition determined by DEXA were measured. Serum leptin levels were significantly increased in patients with CS (36.9+/-3.8 vs 18.9+/-2.4 ng/ml, p<0.001; women: 40.1+/-4.6 vs 21.7+/-2.9 ng/ml, p<0.01; men: 27.9+/-5.7 vs 10.9+/-2.3 ng/ml; p<0.05), the same were fasting insulin levels (178+/-30 vs 81+/-10 pmol/l; p<0.01) and C-peptide (1.51+/-0.12 vs 0.77+/-0.07 nmol/l; p<0.001). In a subgroup of 12 patients, truncal fat mass was significantly elevated when compared to obese controls (19.2 kg vs 14.7 kg, p<0.01, and 42% vs 36% in percentage of truncal body tissue, p<0.05), whereas total fat mass was insignificantly increased. Serum leptin correlated positively to total body fat (%) as in patients with CS (r=0.94, p<0.001) as in controls (r=0.68, p<0.01). The correlation to truncal body fat (%) was also significant in both groups (CS: r=0.84, p<0.001; controls: r=0.63, p<0.01). Multiple regression showed that percent total body fat was the predictor of leptin concentrations among patients with CS (r2=0.88, p<0.001) whereas insulin did not contribute significantly to the variance in leptin concentrations. In controls, both leptin and insulin (r2=0.65, p<0.001) contributed significantly to the variations in leptin levels. Controlled for the differences in total body fat, patients with endogenous CS have significantly increased serum leptin levels, compared to BMI-matched obese controls. This suggests that hyperleptinemia in CS not primarily reflects changes in body composition, but is the result of different hormonal influences on adipose tissue.