Skeletal differences in bone mineral area and content before and after cure of endogenous Cushing's syndrome

Trabecular bone score (TBS) in Cushing's disease: TBS gain after hypercortisolism normalization

CONTEXT

Hypercortisolism frequently induces trabecular bone loss, more pronounced at the lumbar spine, resulting in osteoporosis, and thus an increase in fracture risk. Several studies have shown bone mass recovery in patients with Cushing's disease (CD) after treatment.

OBJECTIVE

To examine treatment effects on TBS (trabecular bone score) in addition to aBMD (areal bone mineral density) in a cohort of patients with CD.

DESIGN AND SETTING

Single-center retrospective longitudinal study in patients diagnosed with CD and successfully treated following surgery and/or medical treatment.

PATIENTS

We included 31 patients with median age and BMI (body mass index) of 37.7 [28.4;43.3] years old and 27.7 [25.8;30.4] kg/m2, respectively. Median 24 h urinary cortisol before treatment was 213.4 [168.5;478.5] μg/24 h. All subjects were completely biochemically controlled or cured after treatment.

MAIN OUTCOME MEASURES

aBMD and TBS were evaluated at AP Spine (L1-L4) with DXA prodigy (GE-Lunar), QDR 4500 (Hologic), and TBS iNsight® (Med-Imaps) before and after treatment.

RESULTS

Absolute TBS and aBMD gains following cure of CD were significant (p < 0.0001, and p < 0.001, respectively). aBMD and TBS increased by +3.9 and 8.2 % respectively after cure of CD. aBMD and TBS were not correlated before (p = 0.43) and after treatment (p = 0.53). Linear regression analyses showed that TBS gain was independent of baseline BMI and that low TBS at baseline was predictive of TBS gain after treatment.

CONCLUSION

The more significant improvement of microarchitecture assessed by TBS than aBMD and the absence of correlation between TBS and aBMD suggest that TBS may be an adequate marker of bone restoration after cure of CD. To support this conclusion, future studies with larger sample sizes and longer follow-up periods should be carried out.

A clinical perspective on ectopic Cushing's syndrome

Cushing's syndrome (CS) refers to the clinical features of prolonged pathological glucocorticoid excess. About 10-20% of individuals with CS have ectopic CS (ECS), that is, an adrenocorticotropin (ACTH)-producing tumour outside the pituitary gland. ACTH-secreting neuroendocrine neoplasia (NENs) can arise from many organs, although bronchial NEN, small cell lung cancer (SCLC), pancreatic NEN, thymic NEN, medullary thyroid cancer (MTC), and pheochromocytoma are the most common. Patients with ECS frequently present with severe hypercortisolism. The risk of life-threatening complications is high in severe cases, unless the hypercortisolism is effectively treated. A good outcome in ECS requires a methodical approach, incorporating prompt diagnosis, tumour localization, control of cortisol excess, and resection of the primary tumour when possible.

Evaluation of bone-related mechanical properties in female patients with long-term remission of Cushing's syndrome using quantitative computed tomography-based finite element analysis

BACKGROUND

Hypercortisolism in Cushing's syndrome (CS) is associated with bone loss, skeletal fragility, and altered bone quality. No studies evaluated bone geometric and strain-stress values in CS patients after remission thus far.

PATIENTS AND METHODS

Thirty-two women with CS in remission (mean age [±SD] 51 ± 11; body mass index [BMI], 27 ± 4 kg/m2; mean time of remission, 120 ± 90 months) and 32 age-, BMI-, and gonadal status-matched female controls. Quantitative computed tomography (QCT) was used to assess volumetric bone mineral density (vBMD) and buckling ratio, cross-sectional area, and average cortical thickness at the level of the proximal femur. Finite element (FE) models were generated from QCT to calculate strain and stress values (maximum principal strain [MPE], maximum strain energy density [SED], maximum Von Mises [VM], and maximum principal stress [MPS]). Areal BMD (aBMD) and trabecular bone score (TBS) were assessed by dual-energy X-ray absorptiometry (2D DXA).

RESULTS

Trabecular vBMD at total hip and trochanter were lower in CS as compared with controls (P < .05). Average cortical thickness was lower, and buckling ratio was greater in CS vs controls (P < .01). All strain and stress values were higher in CS patients vs controls (P < .05). 2D DXA-derived measures were similar between patients and controls (P > .05). Prior hypercortisolism predicted both VM (β .30, P = .014) and MPS (β .30, P = .015), after adjusting for age, BMI, menopause, delay to diagnosis, and duration of remission.

CONCLUSIONS

Women with prior hypercortisolism have reduced trabecular vBMD and impaired bone geometrical and mechanical properties, which may contribute to an elevated fracture risk despite long-term remission.

Musculoskeletal complications of Cushing syndrome

Prolonged exposure to an excess of glucocorticosteroids (GCs), both endogenous and exogenous, leads to a wide range of comorbidities, including cardiovascular, metabolic, psychiatric, and musculoskeletal disorders. The latter comprise osteopenia and osteoporosis leading to skeletal fractures and myopathy. Although endogenous hypercortisolemia is a rare disorder, GCs are among the most frequently prescribed drugs, often administered chronically and despite multiple side effects, impossible to taper off due to therapeutic reasons. The pathophysiology of the effect of GC excess on bone often leads to fractures despite normal or low-normal bone mineral density and it includes direct (mainly disturbance in bone formation processes, through inactivation of the Wnt/β-catenin signalling pathway) and indirect mechanisms (through suppressing the gonadal and somatotrophic axis, and also through antagonizing vitamin D actions). Glucocorticosteroid-induced fast-twitch, glycolytic muscles atrophy occurs due to increased protein catabolism and impaired synthesis. Protein degradation is a result of activation of the ubiquitin proteasome and the lysosomes stimulated through overexpression of several atrogenes (such as FOXO-1 and atrogin-1). This review will discuss pathophysiology, clinical presentation, prevention, and management of GC-induced osteoporosis (including calcium and vitamin D supplementation, and bisphosphonates) and myopathy associated with GC excess.

Relationship between osteoporosis and Cushing syndrome based on bioinformatics

BACKGROUND

Many clinical studies have reported a relatively high incidence of osteoporosis and fragility fractures in patients with Cushing syndrome (CS). However, few papers have investigated osteoporosis and CS in terms of pathogenesis, so this study explores the association between the 2 and predicts upstream micro-ribonucleic acids (miRNAs) through bioinformatics, which provides potential targets for simultaneous pharmacological interventions in both diseases and also provides a basis for pathological screening.

METHODS

We used Genecards, Online Mendelian Inheritance in Man and Therapeutic Target Database databases to screen the targets of osteoporosis and Cushing syndrome; import target genes to Database for Annotation, Visualization and Integrated Discovery for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis; the intersecting genes were uploaded to Search Tool for the Retrieval of Genes and Genomes database to construct protein-protein interaction network; Cytoscape software was used to screen core genes, and Molecular Complex Detection module was used to analyze cluster modules; finally, the NetworkAnalyst data platform was used to predict the miRNAs that interact with core genes.

RESULTS

The core genes of osteoporosis and Cushing syndrome were insulin, tumor necrosis factor, signal transducer and activator of transcription 3 (STAT3), interleukin-6, insulin-like growth factor 1, etc. A total of 340 upstream miRNAs including hsa-let-7a-5p, hsa-mir-30a-5p and hsa-mir-125b-5p were predicted. The biological processes involved include regulating the transcription of ribonucleic acid polymerase II promoter and participating in the transduction of cytokine signaling pathways, which focus on the binding of nerve system ligand, JAK-STAT signaling pathway, Rap1 signaling pathway, PI3K-Akt signaling pathway, etc.

CONCLUSION

Osteoporosis and Cushing syndrome are closely related in terms of targets and molecular mechanisms. In this study, bioinformatics methods were used to identify their targets and mechanisms, providing potential targets for drug simultaneous regulation of the 2 diseases, and providing a new direction for exploring the relationship between diseases.

Regulation of bone mass in endocrine diseases including diabetes

Hormonal regulation plays a key role in determining bone mass in humans. Both skeletal growth and bone loss in health and disease is critically controlled by endocrine factors and low bone mass is a feature of both excess and deficiency of a broad range of hormones. This article explores the impact of diabetes and thyroid, parathyroid, sex steroid and growth hormone disorders on bone mass and fracture risk. Evidence for current management strategies is provided along with suggested practice points and gaps in knowledge for future research.

Assessment of non-traumatic vertebral fractures in Cushing's syndrome patients

PURPOSE

Hypercortisolism has detrimental effects on bone metabolism with the consequences of bone loss and bone fractures. We aimed to evaluate the frequency of vertebral fragility fractures and to determine the factors associated with Cushing's syndrome (CS).

METHODS

A total of 135 patients diagnosed with Cushing's syndrome [108 patients with Cushing's disease and 27 patients with adrenocortical adenoma] and 107 healthy controls were included in this cross-sectional study. The available clinical, laboratory, and radiologic data of patients with CS were recorded, retrospectively. Lateral vertebral radiograms were evaluated for vertebral fragility fractures according to Genant's semi-quantitative method. Bone mineral density (BMD) was determined using a Dual-energy X-ray absorptiometry (DEXA).

RESULTS

Vertebral fragility fractures (VFs) were observed in 75.3% (n = 61) of the patients. The median number of VFs was six (min-max: 2-12). All patients with vertebral fractures had thoracic VF, and 50.7% of the patients had lumbar fragility fractures. Thirty-three (40.7%) patients with vertebral fractures had normal bone densitometry values. Osteoporosis and osteopenia were observed in 16.2% and 40.7% of the patients, respectively. The duration of active disease, the presence of ACTH-secreting pituitary adenoma, and 24-h urinary cortisol did not influence the presence of vertebral fractures. Vertebral fractures were independently associated with age, FSH, LH levels, and lumbar BMD (R² = 68.18%, p = 0.028). The femoral neck BMD (but not lumbar BMD) was independently associated with age, BMI, and PTH levels (R² = 48.48%, p < 0.001).

CONCLUSION

Vertebral fracture frequency was higher in CS patients. Most of the patients with vertebral fractures had multiple fractures. Although low lumbar BMD was associated with VF, patients with CS with normal bone densitometry could experience VF. Vertebral radiograph evaluations as a part of routine evaluation for silent vertebral fractures may help to prevent further fractures in patients with CS.

Osteopathy in mild adrenal Cushing's syndrome and Cushing disease

Pathophysiology and effects of endogenous glucocorticoid (GC) excess on skeletal endpoints as well as awareness and management of bone fragility are reviewed. Cushing's syndrome (CS) increase the risk of fracture affecting prevalently bone quality. Bone antiresorptive agents (SERMs, bisphosphonates and denosumab) as well as teriparatide increase bone mineral density and in some instances reduce fracture risk. Awareness and management of bone health in CS can be improved.

Thyroid Hormones, Glucocorticoids, Insulin, and Bone

Several endocrine systems have important effects on bone tissue. Thyroid hormones are essential for normal growth and development. Excess of these hormones will result in clinically significant changes that may require intervention. Glucocorticoids also have a marked effect on bone metabolism by several pathways. Their endogenous or exogenous excess will induce pathological processes that might elevate the risk of fractures. Insulin and the carbohydrate metabolism elicit a physiological effect on bone; however, the lack of insulin (type 1 diabetes) or insulin resistance (type 2 diabetes) have deleterious influence on bone tissue.

The Effect of Biochemical Remission on Bone Metabolism in Cushing's Syndrome: A 2-Year Follow-Up Study

Endogenous Cushing's syndrome (CS) is a rare cause of secondary osteoporosis. The long-term consequences for bone metabolism after successful surgical treatment remain largely unknown. We assessed bone mineral density and fracture rates in 89 patients with confirmed Cushing's syndrome at the time of diagnosis and 2 years after successful tumor resection. We determined five bone turnover markers at the time of diagnosis, 1 and 2 years postoperatively. The bone turnover markers osteocalcin, intact procollagen-IN-propeptide (PINP), alkaline bone phosphatase, CTX-I, and TrAcP 5b were measured in plasma or serum by chemiluminescent immunoassays. For comparison, 71 sex-, age-, and body mass index (BMI)-matched patients in whom Cushing's syndrome had been excluded were studied. None of the patients received specific osteoanabolic treatment. At time of diagnosis, 69% of the patients had low bone mass (mean T-score = -1.4 ± 1.1). Two years after successful surgery, the T-score had improved in 78% of patients (mean T-score 2 years postoperatively -1.0 ± 0.9). The bone formation markers osteocalcin and intact PINP were significantly decreased at time of diagnosis (p ≤ 0.001 and p = 0.03, respectively), and the bone resorption marker CTX-I and TrAcP 5b increased. Postoperatively, the bone formation markers showed a three- to fourfold increase 1 year postoperatively, with a moderate decline thereafter. The bone resorption markers showed a similar but less pronounced course. This study shows that the phase immediately after surgical remission from endogenous CS is characterized by a high rate of bone turnover resulting in a striking net increase in bone mineral density in the majority of patients. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Cushing's syndrome: Overview of clinical presentation, diagnostic tools and complications

Cushing's syndrome (CS) is a severe condition that results from chronic exposure to elevated circulating cortisol levels; it is a rare but potentially life-threating condition, especially when not timely diagnosed and treated. Even though the diagnosis can be straightforward in florid cases due to their typical phenotype, milder forms can be missed. Despite the availability of different screening tests, the diagnosis remains challenging as none of the available tools proved to be fully accurate. Due to the ubiquitous effect of cortisol, it is easy understandable that its excess leads to a variety of systemic complications including hypertension, metabolic syndrome, bone damages and neurocognitive impairment. This article discusses clinical presentation of CS with an eye on the most frequent cortisol-related comorbidities and discuss the main pitfalls of first- and second-line tests in endogenous hypercortisolism diagnostic workup.

Evaluation of bone health in patients with adrenal tumors

PURPOSE OF REVIEW

Adrenal tumors occur in 5% of population with higher prevalence in elderly. Patients with adrenal tumors present with overt hormonal excess in up to 15% of cases, and mild autonomous cortisol secretion in 30-40% of cases. Overt Cushing syndrome, mild autonomous cortisol secretion, pheochromocytoma, and primary aldosteronism have been associated with higher cardiovascular morbidity and mortality. Increasing experimental and clinical evidence also suggests that adrenal hormone excess is detrimental to bone health. This review aims to discuss the effect of cortisol, aldosterone, and catecholamine excess on bone metabolism, secondary osteoporosis, and fragility fractures.

RECENT FINDINGS

Several studies have reported that patients with hormonally active adrenal tumors demonstrate increased prevalence of fragility fractures incongruous to bone density scan findings. The utility of dual absorptiometry X-ray (DXA) in diagnosing secondary osteoporosis is unclear in patients with cortisol, aldosterone, and catecholamine excess. Trabecular bone score and bone turn over markers could serve as potential diagnostic tools in assessment of severity of bone disease in patients with hormonally active adrenal tumors.

SUMMARY

Adrenalectomy is the mainstay of therapy in patients with overt hormone production. Appropriate case detection strategies to identify patients at risk of fragility fractures are needed in patients not treated with adrenalectomy, such as bilateral primary aldosteronism and mild autonomous cortisol secretion.

Active cushing syndrome patients have increased ectopic fat deposition and bone marrow fat content compared to cured patients and healthy subjects: a pilot 1H-MRS study

OBJECTIVE

Glucocorticoid excess is one of the most important causes of bone disorders. Bone marrow fat (BMF) has been identified as a l new mediator of bone metabolism. Cushing syndrome (CS), is a main regulator of adipose tissue distribution but its impact on BMF is unknown. The objective of the study was to evaluate the effect of chronic hypercortisolism on BMF.

DESIGN

This was a cross-sectional study. Seventeen active and seventeen cured ACTH-dependent CS patients along with seventeen controls (matched with the active group for age and sex) were included.

METHODS

the BMF content of the femoral neck and L3 vertebrae were measured by 1H-MRS on a 3-Tesla wide-bore magnet. BMD was evaluated in patients using dual-energy X-ray absorptiometry.

RESULTS

Active CS patients had higher BMF content both in the femur (82.5±2.6%) and vertebrae (70.1±5.1%) compared to the controls (70.8±3.6%, p=0.013 and 49.0±3.7% p=0.005, respectively). In cured CS patients (average remission time of 43 months), BMF content was not different from controls at both sites (72.3±2.9% (femur) and 46.7%±5.3% (L3)). BMF content was positively correlated with age, fasting plasma glucose, HbA1c, triglycerides and visceral adipose tissue in the whole cohort and negatively correlated with BMD values in the CS patients .

CONCLUSIONS

Accumulation of BMF is induced by hypercortisolism. In remission patients BMF reached values of controls. Further studies are needed to determine whether this increase in marrow adiposity in CS is associated with bone loss.

Glucocorticoids and Bone: Consequences of Endogenous and Exogenous Excess and Replacement Therapy

Osteoporosis associated with long-term glucocorticoid therapy remains a common and serious bone disease. Additionally, in recent years it has become clear that more subtle states of endogenous glucocorticoid excess may have a major impact on bone health. Adverse effects can be seen with mild systemic glucocorticoid excess, but there is also evidence of tissue-specific regulation of glucocorticoid action within bone as a mechanism of disease. This review article examines (1) the role of endogenous glucocorticoids in normal bone physiology, (2) the skeletal effects of endogenous glucocorticoid excess in the context of endocrine conditions such as Cushing disease/syndrome and autonomous cortisol secretion (subclinical Cushing syndrome), and (3) the actions of therapeutic (exogenous) glucocorticoids on bone. We review the extent to which the effect of glucocorticoids on bone is influenced by variations in tissue metabolizing enzymes and glucocorticoid receptor expression and sensitivity. We consider how the effects of therapeutic glucocorticoids on bone are complicated by the effects of the underlying inflammatory disease being treated. We also examine the impact that glucocorticoid replacement regimens have on bone in the context of primary and secondary adrenal insufficiency. We conclude that even subtle excess of endogenous or moderate doses of therapeutic glucocorticoids are detrimental to bone. However, in patients with inflammatory disorders there is a complex interplay between glucocorticoid treatment and underlying inflammation, with the underlying condition frequently representing the major component underpinning bone damage.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

Assessment of vertebral microarchitecture in overt and mild Cushing's syndrome using trabecular bone score

OBJECTIVE

Osteoporotic fractures associated with Cushing's syndrome (CS) may occur despite normal bone mineral density (BMD). Few studies have described alterations in vertebral microarchitecture in glucocorticoid-treated patients and during CS. Trabecular bone score (TBS) estimates trabecular microarchitecture from dual-energy X-ray absorptiometry acquisitions. Our aim was to compare vertebral BMD and TBS in patients with overt CS and mild autonomous cortisol secretion (MACE), and following cure of overt CS.

SETTING

University Hospital.

DESIGN

Monocentric retrospective cross-sectional and longitudinal studies of consecutive patients.

PATIENTS

A total of 110 patients were studied: 53 patients had CS (35, 11 and 7 patients with Cushing's disease, bilateral macronodular adrenal hyperplasia and ectopic ACTH secretion respectively); 39 patients had MACE (10 patients with a late post-operative recurrence of Cushing's disease and 29 patients with adrenal incidentalomas); 18 patients with non-secreting adrenal incidentalomas. 14 patients with overt CS were followed for up to 2 years after cure.

RESULTS

Vertebral osteoporosis at BMD and degraded microarchitecture at TBS were found in 24% and 43% of patients with CS, respectively (P < .03). As compared to patients with nonsecreting incidentalomas, patients with MACE had significantly decreased TBS (P < .04) but not BMD. Overt fragility fractures tended to be associated with low TBS (P = .07) but not with low BMD. TBS, but not BMD values, decreased with the intensity of hypercortisolism independently of its aetiology (P < .01). Following remission of CS, TBS improved more markedly and rapidly than BMD (10% vs 3%, respectively; P < .02).

CONCLUSION

Trabecular bone score may be a promising, noninvasive, widely available and inexpensive complementary tool for the routine assessment of the impact of CS and MACE on bone in clinical practice.

[Acromegaly and Cushing's disease: Persistence of comorbidities after the control of hypersecretion]

Acromegaly and Cushing's disease lead to common and distinct comorbidities. Currently available treatments lead to the control of hyper secretion in the majority of cases. However, the prevalence of the comorbidities does not always go back to the one of the normal population after remission. For instance, about 1/3 of acromegalic patients with diabetes and half of patients with Cushing's disease and diabetes will have normal blood glucose values after remission. In contrast, high blood pressure frequently recovers after remission in both diseases. In contrast, while patients with acromegaly improve their lipid profile, patients with Cushing's disease frequently remain hypertriglyceridemic. Many other comorbidities (cardiovascular disease, bone alterations, altered quality of life) may persist after the control of hyper secretion. The aim of this review is to focus on the outcome of patients with acromegaly and Cuhing's disease, and to suggest the optimal follow-up of such patients in a multidisciplinary approach. These points have been discussed during the 2016 European Congress of Endocrinology, notably by J.Romijn and E.Valassi.

MECHANISMS IN ENDOCRINOLOGY: Endogenous subclinical hypercortisolism and bone: a clinical review

In recent years, the condition of subclinical hypercortisolism (SH) has become a topic of growing interest. This is due to the fact that SH prevalence is not negligible (0.8-2% in the general population) and that, although asymptomatic, this subtle cortisol excess is not harmless, being associated with an increased risk of complications, in particular of osteoporosis and fragility fractures. As specific symptoms of hypercortisolism are absent in SH, the SH diagnosis relies only on biochemical tests and it is a challenge for physicians. As a consequence, even the indications for the evaluation of bone involvement in SH patients are debatable and guidelines are not available. Finally, the relative importance of bone density, bone quality and glucocorticoid sensitivity in SH is a recent field of research. On the other hand, SH prevalence seems to be increased in osteoporotic patients, in whom a vertebral fracture may be the presenting symptom of an otherwise asymptomatic cortisol excess. Therefore, the issue of who and how to screen for SH among the osteoporotic patients is widely debated. The present review will summarize the available data regarding the bone turnover, bone mineral density, bone quality and risk of fracture in patients with endogenous SH. In addition, the role of the individual glucocorticoid sensitivity in SH-related bone damage and the problem of diagnosing and managing the bone consequences of SH will be reviewed. Finally, the issue of suspecting and screening for SH patients with apparent primary osteoporosis will be addressed.

Glucocorticoid-induced osteoporosis: pathophysiological role of GH/IGF-I and PTH/VITAMIN D axes, treatment options and guidelines

Glucocorticoid-induced osteoporosis is the most frequent form of secondary osteoporosis caused by chronic exposure to glucocorticoid excess. Pathogenesis of glucocorticoid-induced osteoporosis is multifactorial including direct effects of glucocorticoids on bone cells and indirect effects of glucocorticoids on several neuroendocrine and metabolic pathways. Fragility fractures occur early in glucocorticoid-induced osteoporosis and anti-osteoporotic drugs along with calcium and vitamin D should be started soon after exposure to glucocorticoid excess. This paper summarizes some of the main topics discussed during the 9th Glucocorticoid-Induced Osteoporosis Meeting (Rome, April 2016) with a specific focus on the role of growth hormone/insulin-like growth factor-1 and parathyroid hormone/vitamin D axes in the pathogenesis of glucocorticoid-induced osteoporosis and the controversial aspects concerning therapeutic approach to skeletal fragility in this clinical setting.

Quantitative CT assessment of bone mineral density in dogs with hyperadrenocorticism

Canine hyperadrenocorticism (HAC) is one of the most common causes of general osteopenia. In this study, quantitative computed tomography (QCT) was used to compare the bone mineral densities (BMD) between 39 normal dogs and 8 dogs with HAC (6 pituitary-dependent hyperadrenocorticism [PDH]; pituitary dependent hyperadrenocorticism, 2 adrenal hyperadrenocorticism [ADH]; adrenal dependent hyperadrenocorticism) diagnosed through hormonal assay. A computed tomogaraphy scan of the 12th thoracic to 7th lumbar vertebra was performed and the region of interest was drawn in each trabecular and cortical bone. Mean Hounsfield unit values were converted to equivalent BMD with bone-density phantom by linear regression analysis. The converted mean trabecular BMDs were significantly lower than those of normal dogs. ADH dogs showed significantly lower BMDs at cortical bone than normal dogs. Mean trabecular BMDs of dogs with PDH using QCT were significantly lower than those of normal dogs, and both mean trabecular and cortical BMDs in dogs with ADH were significantly lower than those of normal dogs. Taken together, these findings indicate that QCT is useful to assess BMD in dogs with HAC.

Complications of Cushing's syndrome: state of the art

Cushing's syndrome is a serious endocrine disease caused by chronic, autonomous, and excessive secretion of cortisol. The syndrome is associated with increased mortality and impaired quality of life because of the occurrence of comorbidities. These clinical complications include metabolic syndrome, consisting of systemic arterial hypertension, visceral obesity, impairment of glucose metabolism, and dyslipidaemia; musculoskeletal disorders, such as myopathy, osteoporosis, and skeletal fractures; neuropsychiatric disorders, such as impairment of cognitive function, depression, or mania; impairment of reproductive and sexual function; and dermatological manifestations, mainly represented by acne, hirsutism, and alopecia. Hypertension in patients with Cushing's syndrome has a multifactorial pathogenesis and contributes to the increased risk for myocardial infarction, cardiac failure, or stroke, which are the most common causes of death; risks of these outcomes are exacerbated by a prothrombotic diathesis and hypokalaemia. Neuropsychiatric disorders can be responsible for suicide. Immune disorders are common; immunosuppression during active disease causes susceptibility to infections, possibly complicated by sepsis, an important cause of death, whereas immune rebound after disease remission can exacerbate underlying autoimmune diseases. Prompt treatment of cortisol excess and specific treatments of comorbidities are crucial to prevent serious clinical complications and reduce the mortality associated with Cushing's syndrome.

The risk factors for fractures and trabecular bone-score value in patients with endogenous Cushing's syndrome

In a cohort study of 182 consecutive patients with active endogenous Cushing's syndrome, the only predictor of fracture occurrence after adjustment for age, gender bone mineral density (BMD) and trabecular bone score (TBS) was 24-h urinary free cortisol (24hUFC) levels with a threshold of 1472 nmol/24 h (odds ratio, 3.00 (95% confidence interval (CI), 1.52-5.92); p = 0.002).

INTRODUCTION

The aim was to estimate the risk factors for fracture in subjects with endogenous Cushing's syndrome (CS) and to evaluate the value of the TBS in these patients.

METHODS

All enrolled patients with CS (n = 182) were interviewed in relation to low-traumatic fractures and underwent lateral X-ray imaging from T4 to L5. BMD measurements were performed using a DXA Prodigy device (GEHC Lunar, Madison, Wisconsin, USA). The TBS was derived retrospectively from existing BMD scans, blinded to clinical outcome, using TBS iNsight software v2.1 (Medimaps, Merignac, France). Urinary free cortisol (24hUFC) was measured by immunochemiluminescence assay (reference range, 60-413 nmol/24 h).

RESULTS

Among enrolled patients with CS (149 females; 33 males; mean age, 37.8 years (95% confidence interval, 34.2-39.1); 24hUFC, 2370 nmol/24 h (2087-2632), fractures were confirmed in 81 (44.5%) patients, with 70 suffering from vertebral fractures, which were multiple in 53 cases; 24 patients reported non-vertebral fractures. The mean spine TBS was 1.207 (1.187-1.228), and TBS Z-score was -1.86 (-2.07 to -1.65); area under the curve (AUC) was used to predict fracture (mean spine TBS) = 0.548 (95% CI, 0.454-0.641)). In the final regression model, the only predictor of fracture occurrence was 24hUFC levels (p = 0.001), with an increase of 1.041 (95% CI, 1.019-1.063), calculated for every 100 nmol/24-h cortisol elevation (AUC (24hUFC) = 0.705 (95% CI, 0.629-0.782)).

CONCLUSIONS

Young patients with CS have a low TBS. However, the only predictor of low traumatic fracture is the severity of the disease itself, indicated by high 24hUFC levels.

Treatment of Cushing's Syndrome: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

The objective is to formulate clinical practice guidelines for treating Cushing's syndrome.

PARTICIPANTS

Participants include an Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. The European Society for Endocrinology co-sponsored the guideline.

EVIDENCE

The Task Force used the Grading of Recommendations, Assessment, Development, and Evaluation system to describe the strength of recommendations and the quality of evidence. The Task Force commissioned three systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

The Task Force achieved consensus through one group meeting, several conference calls, and numerous e-mail communications. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines.

CONCLUSIONS

Treatment of Cushing's syndrome is essential to reduce mortality and associated comorbidities. Effective treatment includes the normalization of cortisol levels or action. It also includes the normalization of comorbidities via directly treating the cause of Cushing's syndrome and by adjunctive treatments (eg, antihypertensives). Surgical resection of the causal lesion(s) is generally the first-line approach. The choice of second-line treatments, including medication, bilateral adrenalectomy, and radiation therapy (for corticotrope tumors), must be individualized to each patient.

Body composition and bone mineral density in women with Cushing's syndrome in remission and the association with common genetic variants influencing glucocorticoid sensitivity

OBJECTIVE

Adverse body compositional features and low bone mineral density (BMD) are the characteristic of patients with active Cushing's syndrome (CS). The aim of this study was to evaluate body composition and BMD in women with CS in long-term remission and the influence of polymorphisms in genes affecting glucocorticoid (GC) sensitivity on these end-points.

DESIGN, PATIENTS AND METHODS

This was a cross-sectional, case-controlled study, including 50 women previously treated for CS and 50 age and gender-matched controls. Median (interquartile range) remission time was 13 (5-19) years. Body composition and BMD were measured with dual-energy X-ray absorptiometry. Five polymorphisms in four genes associated with GC sensitivity were analysed using TaqMan or Sequenom single-nucleotide polymorphism genotyping.

RESULTS

Patients with CS in remission had increased abdominal fat mass (P<0.01), whereas BMD was not significantly different at any site between patients and controls. In patients, the NR3C1 Bcl1 polymorphism was associated with reduced total (P<0.05) and femur neck BMD (P<0.05). The polymorphism rs1045642 in the ABCB1 gene was associated with increased abdominal fat mass (P<0.05) and decreased appendicular skeletal muscle mass (P<0.05). GC replacement was associated with reduced total BMD (P<0.01), BMD at lumbar spine (P<0.05) and increased abdominal fat (P<0.01).

CONCLUSION

Ongoing GC replacement therapy together with polymorphisms in two genes related with GC sensitivity is associated with abdominal obesity and adverse skeletal health in patients with CS in long-term remission.

Recovery from SIADH-associated osteoporosis: a case report

INTRODUCTION

Recent studies show an association between hyponatremia and osteoporosis. We have previously reported a case of severe male osteoporosis due to chronic syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Here, we provide a follow-up on this case after cure of the condition that further supports the causal relationship.

THE CASE

A 38-year-old man had been diagnosed with severe osteoporosis most likely due to chronic SIADH. The SIADH was believed to be idiopathic. A magnetic resonance imaging scan, however, revealed a tumor in the sinus, and biopsies showed an esthesioneuroblastoma, immunohistochemically positive for antidiuretic hormone (ADH). After the tumor was removed, ADH and sodium levels normalized. A dual-energy x-ray absorptiometry scan performed 7 months after the patient's last surgery showed a significant spontaneous improvement in bone mineral density in the lumbar vertebrae.

CONCLUSION

This case provides evidence for a causal relationship between SIADH and chronic hyponatremia and impaired bone metabolism that can lead to severe secondary osteoporosis. The effect on bone metabolism is at least partially reversible.

Treatment of skeletal impairment in patients with endogenous hypercortisolism: when and how?

Guidelines for the management of osteoporosis induced by endogenous hypercortisolism are not available. Both the American College of Rheumatology and the International Osteoporosis Foundation recommend to modulate the treatment of exogenous glucocorticoid-induced osteoporosis (GIO) based on the individual fracture risk profile (calculated by FRAX) and dose of glucocorticoid used, but it is difficult to translate corticosteroid dosages to different degrees of endogenous hypercortisolism, and there are no data on validation of FRAX stratification method in patients with endogenous hypercortisolism. Consequently, it is unclear whether such recommendations may be adapted to patients with endogenous hypercortisolism. Moreover, patients with exogenous GIO take glucocorticoids since suffering a disease that commonly affects bone. On the other hand, the correction of coexistent risk factors, which may contribute to increase the fracture risk in patients exposed to glucocorticoid excess, and the removal of the cause of endogenous hypercortisolism, may lead to the recovery of bone health. Although the correction of hypercortisolism and of possible coexistent risk factors is necessary to favor the normalization of bone turnover with recovery of bone mass; in some patients, the fracture risk could not be normalized and specific anti-osteoporotic drugs should be given. Who, when, and how the patient with endogenous hypercortisolism should be treated with bone-active therapy is discussed.

Glucocorticoid-related bone changes from endogenous or exogenous glucocorticoids

PURPOSE OF REVIEW

Glucocorticoids have a negative impact on bone through direct effects on bone cells and indirect effects on calcium absorption. Here, recent findings regarding glucocorticoid-induced osteoporosis, bone changes in patients with endogenous glucocorticoid derangements, and treatment of steroid-induced bone disease are reviewed.

RECENT FINDINGS

Although the majority of our understanding arises from the outcomes of patients treated with exogenous steroids, endogenous overproduction appears to be similarly destructive to bone, but these effects are reversible with cure of the underlying disease process. Additionally, there are bone changes that occur in diseases that interrupt adrenal glucocorticoid production, both in response to our inability to perfectly match glucocorticoid replacement and also related to the underlying disease process. More investigation is required to understand which patients with endogenous overproduction or underproduction of glucocorticoid would benefit from osteoporosis treatment. Better understood is the benefit that can be achieved with currently approved treatments for glucocorticoid-induced osteoporosis from exogenous steroids. With growing concern of long-term use of bisphosphonates, however, further investigation into the duration of use and use in certain populations, such as children and premenopausal women, is essential.

SUMMARY

Glucocorticoid-induced osteoporosis is a complex disease that is becoming better understood through advances in the study of exogenous and endogenous glucocorticoid exposure. Further advancement of proper treatment and prevention is on the horizon.

Cushing's syndrome: a structured short- and long-term management plan for patients in remission

One hundred years have passed since Harvey Williams Cushing presented the first patient with the syndrome that bears his name. In patients with Cushing's syndrome (CS), body composition and lipid, carbohydrate and protein metabolism are dramatically affected and psychopathology and cognitive dysfunction are frequently observed. Untreated patients with CS have a grave prognosis with an estimated 5-year survival of only 50%. Remission can be achieved by surgery, radiotherapy and sometimes with medical therapy. Recent data indicate that the adverse metabolic consequences of CS are present for years after successful treatment.In addition, recent studies have demonstrated that health-related quality of life and cognitive function are impaired in patients with CS in long-term remission. The focus of specialised care should therefore be not only on the diagnostic work-up and the early postoperative management but also on the long-term follow-up. In this paper, we review the long-term consequences in patients with CS in remission with focus on the neuropsychological effects and discuss the importance of these findings for long-term management. We also discuss three different phases in the postoperative management of surgically-treated patients with CS, each phase distinguished by specific challenges: the immediate postoperative phase, the glucocorticoid dose tapering phase and the long-term management. The focus of the long-term specialised care should be to identify cognitive impairments and psychiatric disorders, evaluate cardiovascular risk, follow pituitary function and detect possible recurrence of CS.

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.

Glucocorticoid-induced osteoporosis: lessons from Cushing's syndrome

Glucocorticoid-induced osteoporosis (GIO) is the most frequent form of secondary bone disorders. Most of our knowledge on its pathogenesis and treatment has been obtained by investigating patients treated with exogenous glucocorticoids. This review will focus on the bone disorder in endogenous Cushing's syndrome, updating recent advances in its pathophysiology, diagnostic aspects and the various predictors which are important in determining bone mineral density (BMD) and fracture risk. We now know strong evidence that beside BMD, bone microarchitecture, one of the most important elements of bone quality, is a key factor in determining fracture risk. Recently, two new methods (spinal deformity index and trabecular bone score) have been shown to be useful markers of bone microarchitecture in GIO. Investigations of GIO in endogenous Cushing's syndrome have also contributed to our understanding on its natural history and reversibility. Relying on recently published guidelines for management of exogenous GIO, a short list of suggestions is provided regarding the optimal diagnostic and therapeutic approach to patients with endogenous GIO.

[Clinical practice guidelines for evaluation and treatment of osteoporosis associated to endocrine and nutritional conditions. Bone Metabolism Working Group of the Spanish Society of Endocrinology]

OBJECTIVE

To provide practical recommendations for evaluation and treatment of osteoporosis associated to endocrine diseases and nutritional conditions.

PARTICIPANTS

Members of the Bone Metabolism Working Group of the Spanish Society of Endocrinology, a methodologist, and a documentalist.

METHODS

Recommendations were formulated according to the GRADE system (Grading of Recommendations, Assessment, Development, and Evaluation) to describe both the strength of recommendations and the quality of evidence. A systematic search was made in MEDLINE (Pubmed), using the following terms associated to the name of each condition: AND "osteoporosis", "fractures", "bone mineral density", and "treatment". Papers in English with publication date before 18 October 2011 were included. Current evidence for each disease was reviewed by two group members, and doubts related to the review process or development of recommendations were resolved by the methodologist. Finally, recommendations were discussed in a meeting of the Working Group.

CONCLUSIONS

The document provides evidence-based practical recommendations for evaluation and management of endocrine and nutritional diseases associated to low bone mass or an increased risk of fracture. For each disease, the associated risk of low bone mass and fragility fractures is given, recommendations for bone mass assessment are provided, and treatment options that have shown to be effective for increasing bone mass and/or to decreasing fragility fractures are listed.

Effect of high-dose glucocorticosteroid treatment for infantile spasms on quantitative bone parameters later in life

This study evaluated possible long-term effects of prolonged high-dose glucocorticosteroid administration in infancy. Thirty patients (16 male, 14 female; age 4.8-33 years) who had completed treatment with adrenocorticotropic hormone (ACTH) followed by glucocorticoids for infantile spasms at a tertiary pediatric hospital at least 2 years previously were invited to undergo quantitative bone ultrasound. The mean speed of soundZ score was -1.085 ± 1.079 for the radius and -0.22 ± 1.19 for the tibia on the nondominant side (P = .0022). The difference from the reference mean (0) was statistically significant for the radius (P < .001). There were no significant differences in radial or tibial mean speed of soundZ scores by age (prepubertal versus pubertal/postpubertal). In conclusion, a high percentage of patients treated with glucocorticoids for infantile spasms have a low radial speed of soundZ score later in life. Long-term follow-up can help to prevent and treat impairments in bone density, especially in non-weight-bearing organs.

Long-term metreleptin treatment increases bone mineral density and content at the lumbar spine of lean hypoleptinemic women

Strenuously exercising young women with hypothalamic amenorrhea are hypoleptinemic and have low bone mineral density (BMD) and content (BMC), which predispose them to increased fracture risk. Short-term leptin replacement in these women corrects many neuroendocrine abnormalities and increases circulating levels of bone formation markers. Whether treatment with recombinant methionyl human leptin (metreleptin) for a long period improves BMD and BMC remains unknown. We studied 20 strenuously exercising young women with hypoleptinemia (leptin concentration <5 ng/mL) and hypothalamic amenorrhea of at least 6 months' duration. Eleven were randomized to metreleptin (initial dose, 0.08 mg/[kg·d] for 3 months; altered thereafter to 0.12 mg/kg for lack of efficacy or 0.04 mg/[kg d] for more than 5% weight loss) and 9 were randomized to placebo for 9 months. After a 3-month washout period, subjects were reexamined at the 1-year time point. Six subjects elected to continue on open-label metreleptin treatment for another 12 months. Two subjects dropped out after 18 months, and 4 completed the entire 2-year study. The BMD and BMC of the total body, lumbar spine (L1-L4), hip, and radius were assessed by using dual-energy x-ray absorptiometry at baseline and at 3, 6, 9, 12, 18, and 24 months of treatment. Metabolic and hormonal parameters and bone markers were measured in blood and urine. Metreleptin significantly increased BMC (P = .034) and tended to increase BMD (P = .069) at the lumbar spine at 9 months in the entire study group (intention-to-treat analysis). In subjects who completed the entire 2-year study (n = 4), metreleptin significantly increased BMD (P = .024) and BMC (P = .049) at the lumbar spine by 4% to 6%. Changes were not significant at the whole body, hip, and radius. Changes in hormonal and metabolic parameters and bone markers were moderate during the first year of treatment, but metreleptin further increased insulin-like growth factor 1 and decreased cortisol and cross-linked C-terminal telopeptide of type 1 collagen concentrations in serum during the second year of treatment (P < .05). The incremental area under the estradiol concentration curve over the 2-year course of the study correlated positively with the corresponding increase in lumbar spine BMD (ρ = 0.42, P = .039). Long-term metreleptin administration in strenuously exercising young women with hypothalamic amenorrhea and hypoleptinemia increases lumbar spine BMD and BMC and alters bone remodeling milieu to favor bone accretion. Results from this pilot study should be confirmed by future, larger clinical trials and need to be extended by studying bone microarchitecture and fracture risk.

Bone demineralization in the lumbar spine of dogs submitted to prednisone therapy

Glucocorticoids are drugs widely used in veterinary medicine; however, besides their clinical benefits, their use can trigger undesirable effects. A clinical trial was performed on eight healthy dogs with the intent of evaluating possible alterations in the bone mineral density after therapy with prednisone using a helical computed tomography. All animals received prednisone orally at a dose of 2 mg/kg of weight for 30 days. The bone mineral density was determined by obtaining the vertebral body radiodensity of the second lumbar vertebra values immediately before and after the administration of the medication. The experimental protocol allowed for the characterization of a significant (P < 0.01) reduction of the vertebral body radiodensity of the second lumbar vertebra. At the end of the experiment, it was characterized by a loss of bone mass of approximately 14%. None of the animals presented pathologic fracture at the end of the administration of the medication. This study verified that the alterations in the bone metabolism of the dogs submitted to the therapy with prednisone in a dosage of 2 mg/kg occur rapidly, which recommends a monitoring of the patients for the prevention of pathologic fractures.

The 83,557insA variant of the gene coding 11β-hydroxysteroid dehydrogenase type 1 enzyme associates with serum osteocalcin in patients with endogenous Cushing's syndrome

OBJECTIVE

The type 1 and type 2 isoenzymes of the 11β-hydroxysteroid dehydrogenase (HSD11B) play an important role in the prereceptor regulation of glucocorticoid bioavailability and action. The potential importance of gene variants coding HSD11B has not been previously evaluated in patients with endogenous hypercortisolism. The aim of the present study was to explore presumed associations between the 83,557insA variant of the HSD11B1 gene and circulating hormone concentrations, bone turnover and bone mineral density (BMD) in patients with endogenous Cushing's syndrome (CS).

PATIENTS AND METHODS

Forty one patients with ACTH-producing pituitary adenomas (Cushing's disease-CD), 32 patients with cortisol-producing adrenal tumors (ACS) and 129 healthy control subjects were genotyped for the 83,557insA variant of the HSD11B1 gene using restriction fragment length analysis. BMD was measured by dual-energy X-ray absorptiometry. Serum cortisol, ACTH, osteocalcin (OC) and C-terminal crosslinks (CTX) of human collagen type I (C-telopeptide) were measured by electrochemiluminescence immunoassay.

RESULTS

No statistically significant differences were found in the allelic frequencies of the 83,557insA polymorphism among patients with CD, ACS and healthy controls. Among all patients with CS, heterozygous carriers of the 83,557insA had significantly higher serum OC as compared to non-carriers. Patients with ACS carrying the 83,557insA variant had higher plasma ACTH concentrations compared to non-carriers. The 83,557insA variant failed to associate with BMD in patients and controls.

CONCLUSIONS

Our present findings indicate that the 83,557insA variant of the HSD11B1 gene may influence serum markers of bone turnover, but not BMD in patients with endogenous Cushing's syndrome.

Adrenal gland and bone

The adrenal gland synthesizes steroid hormones from the adrenal cortex and catecholamines from the adrenal medulla. Both cortisol and adrenal androgens can have powerful effects on bone. The overproduction of cortisol in Cushing's disease leads to a dramatic reduction in bone density and an increase risk of fracture. Overproduction of adrenal androgens in congenital adrenal hyperplasia (CAH) leads to marked changes in bone growth and development with early growth acceleration but ultimately a significant reduction in final adult height. The role of more physiological levels of glucocorticoids and androgens on bone metabolism is less clear. Cortisol levels measured in elderly individuals show a weak correlation with measures of bone density and change in bone density over time with a high cortisol level associated with lower bone density and more rapid bone loss. Cortisol levels and the dynamics of cortisol secretion change with age which could also explain some age related changes in bone physiology. It is also now clear that adrenal steroids can be metabolized within bone tissue itself. Local synthesis of cortisol within bone from its inactive precursor cortisone has been demonstrated and the amount of cortisol produced within osteoblasts appears to increase with age. With regard to adrenal androgens there is a dramatic reduction in levels with aging and several studies have examined the impact that restoration of these levels back to those seen in younger individuals has on bone health. Most of these studies show small positive effects in women, not men, but the skeletal sites where benefits are seen varies from study to study.

Effects of Cushing disease on bone mineral density in a pediatric population

OBJECTIVE

To evaluate bone mineral density (BMD) in children with Cushing disease before and after transphenoidal surgery (TSS).

STUDY DESIGN

Hologic dual-energy x-ray absorptiometry (DXA) scans of 35 children with Cushing disease were analyzed retrospectively. Sixteen of the 35 patients had follow-up DXA scans performed 13 to 18 months after TSS. BMD and bone mineral apparent density (BMAD) for lumbar spine (LS) L1 to L4 and femoral neck (FN) were calculated.

RESULTS

Preoperatively, 38% and 23% of patients had osteopenia of the LS and FN, respectively. Both BMD and BMAD Z-scores of the LS were worse than those for the FN (-1.60 +/- 1.37 versus -1.04 +/- 1.19, P = .003), and (-1.90 +/- 1.49 versus -0.06 +/- 1.90, P < .001); postoperative improvement in BMD and BMAD were more pronounced in LS than in the FN (0.84 +/- 0.88 versus 0.15 +/- 0.62, P<.001; and 0.73 +/- 1.13 versus -0.26 +/- 1.21, P = .015). Pubertal stage, cortisol levels, and length of disease had no effect on BMD.

CONCLUSIONS

In children with Cushing disease, vertebral BMD was more severely affected than femoral BMD and this effect was independent of degree or duration of hypercortisolism. BMD for the LS improved significantly after TSS; osteopenia in this group may be reversible.

Bone turnover in patients with endogenous Cushing's syndrome before and after successful treatment

We investigated bone turnover and its restoration in a large number of patients in the active phase and after cure of endogenous Cushing's syndrome. Furthermore, the usefulness of serum osteocalcin and collagen breakdown products as potential markers of active Cushing's syndrome was also evaluated.

INTRODUCTION

Suppressed bone formation is one of the most characteristic features of Cushing's syndrome (CS). Despite numerous previous reports, many aspects of the disturbed bone metabolism of these patients are unexplored. In this study, we investigated the time course of bone marker changes after the cure of CS as well as correlations between bone markers and serum cortisol concentrations.

METHODS

Eighty-seven patients with CS were studied. Patients were followed up to 48 months after surgical cure. Serum osteocalcin (OC) and collagen breakdown products (CTX) were measured with immunochemiluminescence method and compared to the results of 161 healthy controls.

RESULTS

OC showed a negative, while CTX displayed a positive correlation with serum cortisol. Patients with diabetes mellitus and myopathy had significantly lower serum OC levels compared to those without these complications. The area under the curve of OC obtained by receiver-operating characteristics analysis for the discrimination of patients with CS from healthy controls was 0.9227. Postoperative OC increased rapidly from the first few days or weeks reaching its maximum at the sixth month and remained stable after the 24th postoperative month.

CONCLUSIONS

Our study demonstrated significant correlations between serum cortisol and both bone formation and resorption markers in the active phase of CS. We propose that OC may serve as a sensitive biologic marker of glucocorticoid activity in endogenous CS during its active phase and it may reflect the clinical cure of the disease.

Persistent increase of osteoprotegerin levels after cortisol normalization in patients with Cushing's syndrome

OBJECTIVE

Osteoprotegerin (OPG) has been identified as a decoy receptor that inhibits osteoclast differentiation and, more recently, as a paracrine regulator of vascular calcification. OPG is suppressed by glucocorticoids (GC); however, results from experimental and clinical studies are not univocal. The aim of this study was to evaluate OPG and bone metabolism in patients with Cushing's syndrome (CS) before and after cure.

DESIGN AND METHODS

Twenty-six patients with CS (all women, mean age: 39.1+/-11.9 years) and 24 age- and gonadal status-matched healthy women were studied for bone mineral density, bone metabolism, OPG, and receptor activator of nuclear factor-kB ligand at baseline. Twelve patients were also studied 6-18 months after surgery, with persistent normalization of cortisol levels.

RESULTS

OPG was significantly higher and osteocalcin (OC) was significantly lower in CS patients than in controls (OPG: 4.17+/-1.23 vs 2.95+/-0.79 pmol/l, P=0.00001; OC: 15.0+/-6.1 vs 18.8+/-6.8 ng/ml, P=0.04 in CS and controls respectively). After cure, we found no difference in OPG levels, despite a significant increase in OC levels (from 16.4+/-11 to 37.2+/-15 ng/ml, P=0.03).

CONCLUSION

Patients with CS showed increased OPG serum levels that remained unchanged after recovery, despite a restoration of bone formation. We speculate that high levels of OPG could reflect the persistent damage of the GCs on cardiovascular system.

BclI polymorphism of the glucocorticoid receptor gene is associated with decreased bone mineral density in patients with endogenous hypercortisolism

OBJECTIVE

The hypothalamic-pituitary-adrenal axis setpoint and the glucocorticoid sensitivity of various tissues are at least partially genetically determined. We investigated the impact of glucocorticoid receptor (GR) gene polymorphisms, including the BclI, N363S, ER22/23EK and A3669G variants on bone turnover and/or mineral density (BMD) in patients with endogenous glucocorticoid excess.

DESIGN

Sixty patients including 35 patients with ACTH producing pituitary adenoma (CD) and 25 patients with adrenal Cushing's syndrome (ACS) as well as 129 healthy subjects were genotyped. Analysis of the GR gene polymorphisms were determined using allele specific PCR, PCR-RFLP and Taqman allelic discrimination assays. Hormonal evaluation, BMD and bone marker measurements were carried out.

RESULTS

No significant differences were found in allelic frequencies of the four polymorphisms between patients with ACS, CD and healthy controls. Patients with endogenous hypercortisolism carrying the BclI polymorphism in a homozygous form had reduced BMD at femoral subregions compared to patients with the wild-type variant; femoral neck Z-score (-1.44 +/- 0.73 vs. -0.39 +/- 0.91; P < 0.05), trochanteric Z-score (-1.89 +/- 0.47 vs.-0.54 +/- 0.98; P < 0.05). Patients with homozygous BclI polymorphism had significantly higher beta-CrossLaps Z-scores compared to those with the heterozygous and wild-type variants (+4.42 +/- 2.37 vs. +0.79 +/- 1.67 and +0.11 +/- 1.47; P < 0.01).

CONCLUSIONS

The BclI, N363S, ER22/23EK and A3669G polymorphisms of the GR gene probably do not modify the risk for the development of CD or ACS. Contrary to healthy subjects, however, the BclI polymorphism may modify the skeletal sensitivity to glucocorticoids in patients with endogenous glucocorticoid excess.