New developments in the pathogenesis and treatment of steroid-induced osteoporosis

Recommendations for the Registration of Agents to be Used in the Prevention and Treatment of Glucocorticoid-Induced Osteoporosis: Updated Recommendations from the Group for the Respect of Ethics and Excellence in Science

OBJECTIVES

The Group for the Respect and Excellence in Science (GREES) has reviewed and updated their recommendations for clinical trials to evaluate the efficacy and safety of new chemical entities to be used in the treatment and prevention of glucocorticoid-induced osteoporosis (GIOP).

METHODS

Consensus discussion of the committee.

RESULTS

With the exception of steroid use posttransplantation, there is no need to differentiate between underlying diseases. Prevention and treatment for GIOP are dependent on exposure to glucocorticoids rather than T-scores as in postmenopausal osteoporosis (PMO). If fracture data are obtained for PMO, it need not be repeated for GIOP, relying instead on bone mineral density (BMD) trials of at least 1 year. GREES recommends several changes in the previous guidance for GIOP. The committee saw no need to repeat preclinical studies if those have been previously done to assure bone quality in PMO. Similarly, phase I and phase II trials, if careful dose selection has been done for PMO, should not be repeated. The "prevention" and "treatment" claims should remain. Since the most recent evidence suggests significant increase in fracture risk for daily doses of prednisone of 5 mg/day or equivalent, clinical trials should concentrate on patients receiving at least this daily dosage. The emergence of bisphosphonates as the reference treatment, together with the rapid bone loss and high fracture incidence in glucocorticoid users, necessitates recommending a noninferiority trial design with lumbar spine BMD as the primary endpoint after 1 year.

CONCLUSIONS

Registration of new chemical entities to be used in the management of GIOP should be granted, based on a 1-year noninferiority trial, using BMD as primary outcome and alendronate or risedronate as comparator. Demonstration of antifracture efficacy should have been previously demonstrated in PMO.

Improvement in bone mineral density and body composition in survivors of childhood acute lymphoblastic leukemia: a 1-year prospective study

OBJECTIVES

Abnormalities in bone mineral density (BMD), body composition, and bone metabolism have been reported in children who were treated for acute lymphoblastic leukemia (ALL) during and after completion of therapy. However, these studies are cross-sectional, and no longitudinal data are available in a large group of patients after completion of therapy. In the present study, 1-year longitudinal changes in BMD, body composition, and bone metabolism were evaluated in children with ALL during the first 3 years after completion of therapy without cranial irradiation.

METHODS

BMD of total body (TB; g/cm(2)), areal and apparent volumetric lumbar spine (L2-L4), lean body mass, and percentage of body fat were measured by dual-energy x-ray absorptiometry in 37 children (median age: 7.9 years; range: 4.7-20.6 years) who were treated for ALL at a median age of 3.3 years (range: 1.1-16.6 years), after a median time of 2.2 years after the completion of treatment, and after a 1-year follow-up period. Two control subjects (n = 74) who were matched for gender, age, and pubertal stage were also longitudinally investigated for body composition for 1 year. Usual serum biochemical markers of calcium metabolism and bone turnover were measured in patients during the study period.

RESULTS

A slight decrease in TB BMD was found after a median time of 2.2 years after the completion of therapy for ALL in childhood. Patients showed a significantly lower median TB BMD when evaluated <1.5 years as compared with those at >or=1.5 years since completion of therapy. At the time of first evaluation, the percentage of body fat mass was significantly higher and patients were physically less active than their matched control subjects. Although, as expected, during the 1 year of follow-up both groups showed an annual increment in their BMD measurements, a significantly higher increase in TB BMD was observed in patients in comparison with control subjects. During this same period, the increase in the percentage of body fat mass was slightly lower in ALL patients as compared with control subjects. At the end of the follow-up year, BMD, body-composition parameters, and physical activity of ALL patients were similar to those observed in matched control subjects. Serum biochemical markers of bone turnover were normal at both evaluations.

CONCLUSIONS

A significant increase in TB BMD and a tendency to a lesser increase in percentage of body fat mass were observed during the study period in ALL patients as compared with chronological age-, gender-, and pubertal stage-matched control subjects. These findings suggest a positive effect of long-term completion therapy and increase in physical activity on BMD, body composition, and bone metabolism in patients who have been treated for ALL.

[Prescription of glucocorticoids by rheumatologists in patients with rheumatoid arthritis in Germany]

Systemic GCs are among the most important therapeutic options in modern rheumatology. Due to their fast clinical effects and their high anti-inflammatory potential, they are indispensable in a large number of cases. This applies despite the well-known spectrum of adverse events and despite limited evidence from randomized clinical trials. In this situation, the results of observational studies gain additional importance. They provide information on therapeutic decisions of rheumatologists concerning GC therapy and their combination with other drugs as well as concerning the prevention of adverse events such as GC induced osteoporosis. The data gathered in the national database of the German Collaborative Arthritis Centers show that at the time of documentation 60% of all RA patients were under therapy with GCs, 85% of these were treated with a dosage of up to 7.5 mg/d. GCs are especially frequently used in combination with new or highly potent DMARDs. This underlines that rheumatologists take activity and severity into account in deciding both about GCs and DMARDs. However, there is high practice variation regarding the frequency of GC use among the rheumatological facilities which demonstrates the lack of good evidence.Rheumatologists are aware of various patient risks when prescribing GCs and adapt their therapies to these risks. Two thirds of all patients under GCs were receiving therapy for the prevention or treatment of osteoporosis at documentation, high risk groups such as women over 50 even more frequently. The data emphasize the high importance of GCs in modern rheumatology.

Markers of bone remodeling predict rate of bone loss in multiple sclerosis patients treated with low dose glucocorticoids

BACKGROUND

The aim of this study was to evaluate the clinical value of markers of bone remodeling in assessment of rate of bone loss in patients with multiple sclerosis (MS) long term treated with low dose glucocorticoids.

METHODS

The study involved 70 patients with MS. Motor function of the patients was evaluated using the Kurtzke Expanded Disability Status Scale (KEDSS). Bone mineral density (BMD) was determined at the lumbar spine and proximal femur at baseline and after 1.8 +/- 0.8 years. Bone remodeling was assessed using circulating concentrations of type 1 collagen cross-linked C-telopeptide (beta CTX), aminoterminal propeptide of type I procollagen, and N-MID osteocalcin (OC). A control group of 140 age-matched healthy subjects was used to compare bone-turnover markers.

RESULTS

The plasma CTX concentration was the most significant parameter of bone remodeling which correlated with the rate of bone loss and with the KEDSS. The rate of bone loss at the proximal femur was not significantly different between tertiles of plasma OC concentrations.

CONCLUSION

In physically active patients with MS treated with low-dose GC, the bone-turnover markers were not different from controls. Patients having plasma CTX but markers of bone formation higher as compared to controls were confirmed 2 years later as bone losers.

Differences in hip quantitative computed tomography (QCT) measurements of bone mineral density and bone strength between glucocorticoid-treated and glucocorticoid-naive postmenopausal women

Chronic treatment with glucocorticoids (GCs) leads to significant bone loss and increased risk of fractures. In chronically GC-treated patients, hip fracture risk is nearly 50%. The purpose of this investigation was to determine if there are differences in the quantities of trabecular and cortical bone and bone strength of the hip between GC-treated osteoporotic patients and controls.

METHODS

Study subjects were GC-treated osteoporotic postmenopausal women, and controls were postmenopausal women, recruited for separate clinical trials. Quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA) of the hip were obtained from all subjects. QCT outcome variables measured included total, cortical, and trabecular BMD of hip subregions (femoral neck and trochanter) and total hip. In addition, finite element modeling (FEM) was performed on a subset of 19 cases and 38 controls, matched on age (+/- 5 years), weight (+/- 5 kg), and history of hormone replacement (> 1 year use) to assess failure load in stance and fall loading conditions. Generalized linear models were used to adjust the QCT variables for covariates between groups. Multiple regression was performed to identify independent predictors of bone strength from the QCT variables.

RESULTS

Compared with controls, GC-treated subjects were significantly (p < 0.05) younger, weighed less, and had more years of hormone replacement. QCT of the hip in GC-treated subjects for total femoral integral, cortical, and trabecular BMD averaged 4.9-23.2% (p < 0.002) less than controls, and similar results were seen by hip subregion including the trochanter and femoral neck. DXA of the total hip was 17% lower in GC subjects than controls (p < 0.05). Compared with controls, FEM failure load in GC subjects was 15% (p<0.05) and 16% (p = 0.07) lower for stance and fall loading conditions, respectively. Multiple regression analysis demonstrated that a combination of QCT measures was correlated with bone strength as measured by FEM.

CONCLUSIONS

Chronic GC treatment in postmenopausal women resulted in significantly decreased BMD of the hip, measured by QCT, with loss of both trabecular and cortical bone. In addition, GC treatment decreased bone strength as determined by FEM. The reduced cortical and trabecular bone mass in the hip may contribute to the disproportionately high hip fracture rates observed in GC-treated subjects.

Comparaison des effets de la ciclosporine-A et du tacrolimus sur le métabolisme osseux des patients transplantés rénaux : une étude transversale chez 28 patients

BACKGROUND

Controversy exists about the effects of calcineurin inhibitors on bone metabolism. We decided to compare the effects of CyA vs FK506 on bone metabolism of kidney recipients.

PATIENTS AND METHODS

From 94 patients grafted at the University Hospital of Nice between 1996 and 1999 treated either by CyA (N=49) or by FK506 (N=45), we selected 14 pairs (18 M, 10F), matched for gender, BMI, time lapsed since transplantation and gonadal status in females. Patients with>1 transplantation or>1 rejection episode were excluded. Cumulative dose of steroids was recorded. Bone mineral density (BMD) was mesured at heel and forearm, as well as serum concentration of calcium, phosphate, parathyroid hormone (PTH), vitamin D metabolites, C-telopeptide (CTX), creatinine, estradiol as well as Bone Alkaline Phosphatase (BAP) activity.

RESULTS

Despite the matching, time on hemodialysis was longer in FK506 group. Cumulative dose of steroids was similar between groups. There was no difference between groups in BMD and biochemical parameters except for estradiol serum levels which were dramatically lower in FK506 than in CsA (P=0,02) and for a trend (p=0,08) for BAP and CTX to be higher in FK506 than in CsA.

CONCLUSIONS

BMD is not lower in FK506- than in CsA-treated patients although exposure to hyperparathyroidism was longer and estradiol levels were lower in the FK506 than in the CsA group. These data suggest that FK506 may have a favorable bone effect to compensate for these deleterious factors. This hypothesis remains to be tested in longitudinal studies.

Glucocorticoid suppresses the canonical Wnt signal in cultured human osteoblasts

To explore the mechanism of glucocorticoid-induced osteoporosis, we investigated the effect of glucocorticoid on canonical Wnt signaling that emerged as a novel key pathway for promoting bone formation. Wnt3a increased the T-cell factor (Tcf)/lymphoid enhancer factor (Lef)-dependent transcriptional activity in primary cultured human osteoblasts. Dexamethasone suppressed this transcriptional activity in a dose-dependent manner, while 1,25-dihydroxyvitamin D3 increased this transcriptional activity. LiCl, an inhibitor of glycogen synthase kinase-3beta, also enhanced the Tcf/Lef-dependent transcriptional activity, which was, however, not inhibited by dexamethasone. The addition of anti-dickkopf-1 antibody partially restored the transcriptional activity suppressed by dexamethasone. Dexamethasone decreased the cytosolic amount of beta-catenin accumulated by Wnt3a and also inhibited the nuclear translocation of beta-catenin induced by Wnt3a. These data suggest that glucocorticoid suppresses the canonical Wnt signal in cultured human osteoblasts, partially through the enhancement of the dickkopf-1 production.

Genomic and non-genomic actions of sex steroids in the growth plate

Sex steroids, and particularly estrogens, are important regulators of bone growth and bone mass accrual. For a long time, it was thought that these effects were mainly caused by their modulatory effects on the somatotrophic axis. Data gathered in the past years have challenged this view and it is now widely accepted that many of the effects of sex steroids on growth and bone mass accrual are caused by direct effects on target cells in the growth plate and bone. This review summarizes and discusses some of our latest findings on the expression of sex steroid receptors in the growth plate, the source of the ligands activating these receptors, and their putatitive mechanism of action predominantly focusing on observations in the rat.

Developments in Glucocorticoid Therapy

Recent evidence for a disease-modifying potential of low-dose glucocorticoids (GCs) in the treatment of rheumatoid arthritis has renewed the debate on the risk benefit ratio with this therapy. Two recent developments are described that might have a positive influence on these risk benefit ratios. One is the improvement in new GC compounds--designer GCs, alterations in bioactivity, and alterations in formulations. The other is a better understanding and management of the toxicity of GCs.

Capsaicin-sensitive sensory neurons contribute to the maintenance of trabecular bone integrity

This investigation used capsaicin to selectively lesion unmyelinated sensory neurons in rats. Neuronal lesioning induced a loss of trabecular integrity, reduced bone mass and strength, and depleted neuropeptides in nerve and bone. These data suggest that capsaicin-sensitive sensory nerves contribute to trabecular bone integrity.

INTRODUCTION

Familial dysautomia is an autosomal recessive disease in which patients suffer from unmyelinated sensory neuron loss, reduced BMD, and frequent fractures. It has been proposed that the loss of neurotransmitters synthesized by unmyelinated neurons adversely affects bone integrity in this hereditary syndrome. The purpose of this study was to determine whether small sensory neurons are required for the maintenance of bone integrity in rats.

MATERIALS AND METHODS

Ten-month-old male Sprague-Dawley rats were treated with either capsaicin or vehicle. In vivo DXA scanning and micro CT scanning, and histomorphometry were used to evaluate BMD, structure, and cellular activity. Bone strength was measured in distal femoral sections. Body weight and gastrocnemius/soleus weights were measured and spontaneous locomotor activity was monitored. Peroneal nerve morphometry was evaluated using light and electron microscopy. Substance P and calcitonin gene-related peptide (CGRP) content in the sciatic nerve and proximal tibia were determined by enzyme immunoassay (EIA). Substance P signaling was measured using a sciatic nerve stimulation extravasation assay.

RESULTS

Four weeks after capsaicin treatment, there was a loss of BMD in the metaphyses of the tibia and femur. In the proximal tibia, the osteoclast number and surface increased, osteoblast activity and bone formation were impaired, and trabecular bone volume and connectivity were diminished. There was also a loss of bone strength in the distal femur. No changes occurred in body weight, 24-h grid-crossing activity, weight bearing, or muscle mass after capsaicin treatment, indicating that skeletal unloading did not contribute to the loss of bone integrity. Capsaicin treatment destroyed 57% of the unmyelinated sensory axons, reduced the substance P and CGRP content in the sciatic nerve and proximal tibia, and inhibited neurogenic extravasation.

CONCLUSION

These results support the hypothesis that capsaicin-sensitive sensory neurons contribute to the maintenance of trabecular bone integrity. Capsaicin-sensitive neurons have efferent functions in the tissues they innervate, effects mediated by transmitters released from the peripheral nerve terminals. We postulate that the deleterious effects of capsaicin treatment on trabecular bone are mediated by reductions in local neurotransmitter content and release.

Modulation of bone turnover by alfacalcidol and/or alendronate does not prevent glucocorticoid-induced osteoporosis in growing minipigs

The study was performed to clarify the effects of active vitamin D (alfacalcidol) and/or alendronate (ALN) on bone tissue turnover in glucocorticoid (GC)-treated growing minipigs. Göttingen minipigs aged 8 months were divided into six groups (n = 5 each): group BC, killed for baseline control; group GC, injected subcutaneously with prednisolone (0.5 mg/kg body weight [BW] per day, 5 days/week for 24 weeks); group VC, treated with vehicle alone; group alf, treated with oral alfacalcidol at 0.1 microm/kg BW per day, 5 days/week; group ALN, treated with alendronate 1 mg/kg BW per day; and group alf* ALN, treated with both alf and ALN as above. Biochemical examinations dual-energy X-ray absorptiometry, micro-computed tomography, peripheral quantitative computed tomography, and histomorphometry were performed. In group GC, all bone chemical markers were lower than in group VC. GC treatment reduced the age-dependent augmentation of bone mass and structure by reducing the bone formation rate (BFR) and activation frequency (Ac.f) relative to VC in lumbar bone and femoral cortex. Trabecular and osteonal wall thickness values did not change by GC. Treatments with alf, ALN, and alf* ALN did not have substantial effects on bone mass or structure. Alf treatment maintained lumbar BFR and Ac.f, while ALN reduced osteoclasts. Femoral cortical Ac.f values were not affected by these treatments. GC caused reduced bone formation, leading to low tissue turnover and imbalance of bone formation and resorption. Modulation of bone tissue turnover by alfacalcidol and/or alendronate failed to maintain the growth-dependent increases in mass and structure in GC-treated young minipigs.

An evaluation of managing and educating patients on the risk of glucocorticoid-induced osteoporosis

OBJECTIVE

To assess the impact of risk management activities on patient risk of glucocorticoid-induced osteoporosis.

METHODS

Ninety-six adult patients taking chronic glucocorticoid therapy in 15 community pharmacies. Patients in the control group received usual and customary care. Patients in the treatment pharmacies received education and an educational pamphlet about the risks of glucocorticoid-induced osteoporosis. In addition, the treatment group pharmacists monitored the patients' drug therapy, to identify and address drug-related problems. Data including the glucocorticoid taken by the patient, medications, and osteoporosis risk factors were collected at baseline and after 9 months of monitoring, via Web-based survey completed in the pharmacy. Using an intent to treat approach, the pre-post frequency changes were compared with contrasts for presence of bisphosphonate therapy, presence of estrogen therapy, presence of calcium supplement, discussion of glucocorticoid-induced osteoporosis risk, discussion of bone density test, presence of bone mineral density test, reported inactivity, and reported low calcium diet.

RESULTS

The contrast was significant in favor of the treatment pharmacies for the frequency of patients taking a calcium supplement (Control [-6.9%] vs. Treatment [17.1%], P < 0.05). No other contrast was significant.

CONCLUSIONS

Community pharmacists are capable of increasing calcium supplementation among patients at risk for glucocorticoid-induced osteoporosis. Pharmacists who educate at-risk patients can impact the self-care of these patients.

Current use of glucocorticoids in patients with rheumatoid arthritis in Germany

OBJECTIVE

To describe the current use of glucocorticoids in German patients with rheumatoid arthritis (RA).

METHODS

We analyzed clinical and patient-derived data from 10,068 outpatients with RA from the national database of the German Collaborative Arthritis Centres for the year 2001 collected by more than 80 rheumatologists in hospitals and private practices.

RESULTS

Systemic glucocorticoid therapy was prescribed for 60% of all patients with RA in rheumatologic care. The proportion of patients receiving systemic glucocorticoids in addition to disease-modifying antirheumatic drug (DMARD) therapy ranged from 53% to 81% of the patients for the various DMARDs. Glucocorticoid therapy was administered more often in combination with tumor necrosis factor inhibitors (81%), cyclosporin A (80%), or leflunomide (77%) than with more traditional DMARDs such as methotrexate (63%) or sulfasalazine (55%). Regarding the prevention and treatment of osteoporosis, 63% of patients taking systemic glucocorticoids were also receiving some type of osteoporosis therapy, as opposed to only 26% of those not taking glucocorticoids.

CONCLUSION

Glucocorticoids play a pivotal role in the management of RA. This is reflected in the extensive use of low-dose glucocorticoids by German rheumatologists. Even if highly effective DMARDs are prescribed, they are accompanied by glucocorticoids, at least in the initial phase. High-dose glucocorticoids are prescribed for only a small proportion of the patients. There is increasing awareness of the risk of osteoporosis in long-term glucocorticoid treatment, demonstrated by the fact that osteoporosis medication is prescribed for a large proportion of patients taking glucocorticoids.

Steroid effects on osteogenesis through mesenchymal cell gene expression

We have studied the mechanism of steroid-induced osteonecrosis by examining the effect of dexamethasone on a multipotential cell line, D1, which is derived from bone marrow and is capable of differentiating into either the osteoblast or the adipocyte lineage. The expression of bone cell and fat cell transcription factors Cbfa1/Runx2 and PPARgamma2, were determined. Osteocalcin promoter activity was measured by co-transfecting the cells with the phOC-luc and pSV beta-Gal plasmids. Dexamethasone increased PPARgamma2 gene expression 2-fold, while Cbfa1/Runx2 gene expression and osteocalcin promoter activity decreased by 50-60%, and VEGF protein, measured by ELISA, decreased by 55%. These changes indicate enhanced adipogenesis and decreased osteogenesis by mesenchymal cells in vitro, together with a decrease in VEGF, a potent angiogeneic factor, suggesting that dexamethasone may shunt uncommitted osteoprogenitor cells in marrow from osteoblastic differentiation into the adipocytic pathway, leading to diminished vascularization and eventual osteonecrosis.

Low-dose parathyroid hormone and estrogen reverse alkaline phosphatase activity suppressed by dexamethasone in mouse osteoblastic cells

Glucocorticoid (GC)-induced osteoporosis (GIO) is frequently seen in patients with excessive GC. Numerous questions remain to be clarified about the pathogenesis and treatment of GIO, and the mechanism of GC-inhibited bone formation is not well known. Several studies suggest that parathyroid hormone (PTH) and hormone replacement therapy are effective for GIO. We therefore investigated whether PTH and estrogen would affect cell proliferation and alkaline phosphatase (ALP) activity inhibited by dexamethasone (Dex) in mouse osteoblastic cell-line MC3T3-E1 cells. Low-dose (10(-11) M) PTH as well as 10(-8) M 17-beta-estradiol (17beta-E2) significantly attenuated Dex-inhibited ALP activity, although 10(-8) M PTH did not affect it. ICI 182780 (10(-8) M) antagonized the effects of 17beta-E(2) on Dex-suppressed ALP activity. Neutralizing anti-IGF-I antibody (3 microg/ml) blocked the reverse effects of 17beta-E2 on ALP activity suppressed by Dex. PTH (10(-11) M), but not 17beta-E2, significantly attenuated [3H]thymidine incorporation inhibited by Dex. On the other hand, PTH and estrogen did not affect the level of 11-beta-hydrosteroid dehydrogenase type I mRNA increased by Dex. In conclusion, the present study demonstrated that low-dose PTH and estrogen reversed Dex-inhibited ALP activity in the mouse osteoblastic cell-line.

[Corticosteroid-induced osteoporosis]

A FREQUENT PRESCRIPTION: Corticosteroids are widely prescribed in the long-term treatment of various pathologies (chronic inflammatory rheumatic diseases, asthma and allergic diseases, auto-immune diseases...). CONSEQUENCE OF BONE LOSS: Corticosteroids can be responsible for side effects such as corticosteroid-induced osteoporosis and the increase in risk of fracture is one of the major problems. Great progress in the field of epidemiology, diagnosis, physiopathology and treatment has led to the elaboration of rational and efficient care of patients receiving corticosteroids.

Skeletal status assessed by quantitative ultrasound at the calcaneus in females with bronchial asthma on prolonged corticosteroid therapy

OBJECTIVE

The aim of the study was to assess skeletal status in bronchial asthma female patients after long-term oral corticosteroid (CS) therapy.

METHODS

Eighty-two female patients (25 with and 57 without fractures; mean age 58.0+/-7.8 years) were compared with 999 females (821 controls without fractures, mean age 58.6+/-7.2 years and 178 females with previous osteoporotic fractures, mean age 57.8+/-7.1 years). Mean age and years since menopause did not differ between patients and controls. The duration of CS therapy was 8.4+/-7.3 years, and daily mean dose equivalent to prednison was 8.8+/-3.5 mg. Skeletal status was evaluated by quantitative ultrasound (QUS) measurements at the heel using the Achilles system (Lunar, USA) which measures speed of sound (SOS (m/s)) and Broadband Ultrasound Attenuation (BUA (dB/MHz)). The Achilles software also calculates a stiffness index (SI (%)). The precision expressed using the root mean square coefficient of variation (RMS_CV%) was: 0.26% for SOS, 4.37% for BUA, and 2.13% for SI.

RESULTS

Patients (all, with and without fractures) had significantly lower QUS values than controls without fractures and their values did not differ significantly from controls with fractures. Controls with fractures had significantly lower QUS values than controls without fractures. There was no difference between patients with and without fractures. The duration of the therapy did not influence skeletal variables in any group. Receiver operating characteristic curve (ROC) analysis was performed to assess the discriminatory capability of calcaneal QUS for CS-treated patients by calculating the area under the ROC curve (AUC). AUCs were: 0.70 for SOS, 0.68 for BUA and 0.70 for SI.

CONCLUSIONS

In females with bronchial asthma on prolonged CS therapy, skeletal status is affected but does not differ from controls with fractures therefore CS therapy seems to be a risk factor for osteoporotic fracture. Calcaneal QUS measurements can be a useful tool in the assessment of CS bone-side effects.

Glucocorticoids inhibit the transcriptional activity of LEF/TCF in differentiating osteoblasts in a glycogen synthase kinase-3beta-dependent and -independent manner

Glucocorticoids, widely used as immune suppressors, cause osteoporosis by inhibiting bone formation. In MC3T3-E1 osteoblast-like cultures, dexamethasone (DEX) activates glycogen synthase kinase-3beta (GSK3beta) and inhibits a differentiation-related cell cycle that occurs at a commitment stage immediately after confluence. Here we show that DEX inhibition of the differentiation-related cell cycle is associated with a decrease in beta-catenin levels and inhibition of LEF/TCF-mediated transcription. These inhibitory activities are no longer observed in the presence of lithium, a GSK3beta inhibitor. DEX decreased the serum-responsive phosphorylation of protein kinase B/Akt-Ser(473) within minutes, and this inhibition was also observed after 12 h. When the phosphatidylinositol 3-kinase (PI3K)/Akt pathway was inhibited by wortmannin, DEX no longer inhibited beta-catenin levels. Furthermore, DEX-mediated inhibition of LEF/TCF transcriptional activity was attenuated in the presence of dominant negative forms of either PI3K or protein kinase B/Akt. These results suggest cross-talk between the PI3K/Akt and Wnt signaling pathways. Consistent with a role for Wnt signaling in the osteoblast differentiation-related cell cycle, wortmannin partially negated the DEX inhibition of this cell cycle. DEX also induced histone deacetylase (HDAC) 1, which is known to inhibit LEF/TCF transcriptional activity. Overexpression of HDAC1 negated the inhibitory effect of DEX on LEF/TCF transcriptional activity. In the presence of trichostatin A, a deacetylase inhibitor, DEX-mediated inhibition of the differentiation-related cell cycle was partially negated. When administered together, wortmannin and trichostatin A completely negated the inhibitory effect of DEX on the differentiation-related cell cycle. These results suggest that inhibition of a PI3K/Akt/GSK3beta/beta-catenin/LEF axis and stimulation of HDAC1 cooperate to mediate the inhibitory effect of DEX on Wnt signaling and the osteoblast differentiation-related cell cycle.

Effect of single doses of dexamethasone and adrenocorticotrop hormone on serum bone markers in healthy subjects and in patients with adrenal incidentalomas and Cushing's syndrome

The aim of the present study was to explore whether short-term changes in glucocorticoid activity which occur during dynamic testing of the pituitary adrenal axis with dexamethasone, ACTH, or metyrapone could have an effect on serum osteocalcin (OC) and beta-crosslaps (beta-CTx) concentrations in healthy subjects, in patients with adrenal incidentalomas and in those with Cushing's syndrome. The study included 40 healthy subjects (35 women and 5 men, age range 18-69 yr), 49 patients with adrenal incidentalomas (34 women and 15 men, age range 19-77 yr) and 8 patients with Cushing's syndrome (5 cortisol-producing adenomas and 3 pituitary-dependent Cushing's syndrome, 3 women and 5 men, age range 19-70 yr). Serum OC and beta-CTx concentrations were determined with electrochemoluminescent immunoassays at midnight, after an overnight fast between 08:00 and 09:00 h, after an overnight dexamethasone test (1 mg, orally) and after a single dose of metyrapone (30 mg/kg, orally). In healthy subjects and in patients with adrenal incidentalomas, serum bone marker concentrations were also measured after a single dose of ACTH injection (Cortrosyn depot, 1 mg im). Patients with Cushing's syndrome, but not those with adrenal incidentalomas, showed significantly lower serum OC at midnight (18.5+/-12 ng/ml, mean+/-SD) and between 08:00 and 09:00 h (17.7+/-9.6 ng/ml) compared to corresponding values obtained in healthy subjects (24.5+/-7.0 and 28.3+/-12.2 ng/ml, respectively). Serum OC concentrations were significantly decreased after a single dose of 1-mg dexamethasone in healthy subjects (from 28.3+/-12.2 to 21.8+/-9.5 ng/ml) and in patients with adrenal incidentalomas (from 29.8+/-15.9 to 24.1+/-14.1 ng/ml), whereas serum OC concentrations remained unchanged in patients with Cushing's syndrome. In addition, serum OC concentrations were even more markedly decreased after a single dose of ACTH injection in both healthy subjects (12.5+/-4.6 ng/ml) and in patients with adrenal incidentalomas (12.2+/-6.5 ng/ml). By contrast, metyrapone administration failed to induce significant changes in OC levels. There were no significant differences in beta-CTx concentrations between the three groups or after drug treatments. Thus, serum OC levels should be interpreted with caution when obtained during testing of the pituitary-adrenal axis with dexamethasone or ACTH.

Quantitative ultrasound at the calcaneus in corticosteroid-treated male patients with bronchial asthma

The aim of the study was to assess skeletal status in bronchial asthma male patients after long-term corticosteroid (CSt) therapy. A total of 25 men patients (mean age 53.8 +/- 11.6 years) were compared with 343 men: 256 control men without fractures (mean age 54.4 +/- 13.1 years) and 87 men with previous osteoporotic fractures (mean age 54.7 +/- 11.6 years). The mean age and body size did not differ among groups studied. The duration of CSt therapy expressed as median was 6 years (range 1 to 30 years), and a mean dose equivalent to prednisone was 9.3 +/- 4.5 mg. Skeletal status was evaluated by quantitative ultrasound (QUS) measurements at the heel using the Achilles system (Lunar), which measures speed of sound (SOS) in m/s and broadband ultrasound (US) attenuation (BUA) in dB/MHz. The Achilles software calculates also a stiffness index (SI) in %. The CV% values were: 2.48% for BUA, 0.33% for SOS and 2.56% for SI. Values of BUA, SOS, SI, T-score and Z-score in patients were significantly lower than in controls and did not differ between patients and men with fractures. The duration of CSt therapy and childhood and current calcium daily intake did not influence skeletal variables measured. ROC analysis was performed to assess the discriminatory capability of calcaneal QUS for fractured and CSt-treated patients by calculating the area under the ROC curve (AUC). AUCs were: 0.74 +/- 0.027 and 0.72 +/- 0.05 for SOS, 0.71 +/- 0.03 and 0.66 +/- 0.05 for BUA and 0.74 +/- 0.03 and 0.71 +/- 0.05 for SI, respectively. Concluding, in male patients with bronchial asthma on prolonged CSt therapy, skeletal status was affected, and calcaneal QUS measurements can be a useful tool in the assessment of skeletal side effects after long-term CSt treatment.

The effect of the steroid-sparing response to low-dose methotrexate on bone metabolism in glucocorticoid-dependent asthmatics

BACKGROUND

The skeletal effects of low-dose methotrexate (MTX), in glucocorticoid-dependent asthmatics (GCDA), are unknown.

METHODS

We studied 9 patients from a total of 26 chronic GCDA who completed 28 weeks of MTX (15 mg weekly, intramuscularly). Prednisolone dose was not altered during the first 12 weeks, and was then reduced between 12 and 28 weeks. Mean (S.E.M.) age of the patients was 54 (4.0) years. They had normal bone mineral density (BMD), were not taking medication that affected bone metabolism (except prednisolone and inhaled corticosteroids) and all achieved at least 50% reduction in prednisolone dose at 28 weeks. Blood and urine samples were obtained at baseline, 12, 28 and 40 weeks for measurement of serum osteocalcin (OC) and bone alkaline phosphatase (Bone-ALP) as formation markers and urinary deoxypyridinoline (DPD) and N-terminal cross-linked telopeptide of type I collagen (NTX-I) as resorption markers.

RESULTS

Concurrently with the changes in prednisolone dosage serum OC levels increased significantly at 28 weeks (p<0.008) (8.1+/-1.0 ng/ml) compared to baseline (4.7+/-0.6 ng/ml) and 12 weeks (5.1+/-0.6 ng/ml), but trended back by 40 weeks (6.6+/-0.6 ng/ml). No significant changes were observed for the other bone markers between baseline and the other time points.

CONCLUSIONS

The beneficial effects of steroid reduction on bone metabolism do not appear to be impaired by concomitant MTX treatment at least over 12 weeks.

Strategic approaches to osteoporosis in transplantation

Recipients of stem cell transplantation are at risk for osteopenia and osteoporosis. Longitudinal studies performed in adults have shown that significant bone demineralization occurs following myeloablative therapy and subsequent immune suppression. Among children and adolescents, cross-sectional analyses indicate that younger patients are also at risk for long-term bone toxicity. Strategies to detect and manage this disorder in pediatric SCT recipients are presented.

Autonomic neural signals in bone: Physiological implications for mandible and dental growth

Signals derived from the autonomic nervous system exert potent effects on osteoclast and osteoblast function. A ubiquitous sympathetic and sensory innervation of all periosteal surfaces exists and its disruption affects bone remodeling. Several neuropeptides, neurohormones and neurotransmitters and their receptors are detectable in bone. Bone mineral content decreased in sympathetically denervated mandibular bone. When a mechanical stress was superimposed on mandibular bone by cutting out the lower incisors, an increase in bone density ensued providing the sympathetic innervation was intact. A lower eruption rate of sympathetically denervated incisors at the impeded eruption side, and a higher eruption rate of denervated incisors at the unimpeded side were also observed. A normal sympathetic neural activity appears to be a pre-requisite for maintaining a minimal normal unimpeded incisor eruption and for keeping the unimpeded eruption to attain abnormally high velocities under conditions of stimulated incisor growth. These and other results suggest that the sympathetic nervous system plays an important role in mandibular bone metabolism.

Use of quantitative ultrasound of the hand phalanges in the diagnosis of two different osteoporotic syndromes: Cushing's syndrome and postmenopausal osteoporosis

The aim of this study was to assess the ability of the quantitative ultrasound of the hand phalanges to detect different types of osteoporosis resulting from different pathogenetic mechanisms. For this purpose, postmenopausal and glucocorticoid-induced osteoporosis was studied. Thirteen female patients with Cushing's syndrome (CS) resulting from pituitary-dependent bilateral adrenal hyperplasia (10 patients) and from adrenal adenoma (3 patients), and 32 postmenopausal osteoporotic (OP) women, were examined. The two groups of patients were comparable for body mass index (BMI), but CS patients were significantly younger than OP ones (CS 44.5+/-11.6; OP: 73.9+/-3.6). All the patients had femoral neck bone mineral density (BMD) T-score less than -2.0. Cushing patients had a femoral neck BMD similar to that of OP patients (CS: 603+/-66 mg/cm2; OP: 628+/-69 mg/cm2; p=0.19). In contrast, amplitude-dependent speed of sound (AD-SoS) was significantly higher in CS patients than in OP patients (CS: 1997+/-91 m/s; OP: 1707+/-114 m/s; p<0.0001). By adjusting DXA and ultrasound parameters according to age, femoral neck BMD was significantly lower in CS patients and AD-SoS remained significantly higher than in OP patients. These findings indicate that these two different kinds of osteoporosis can be distinguished by ultrasonography and that ultrasound parameters alone cannot be used for evaluating skeletal status in CS patients.

Incidence of hip osteonecrosis among renal transplantation recipients: a prospective study

AIM

To investigate whether a lessened glucocorticoid cumulative dose would lead to a decreased incidence of femoral head osteonecrosis.

METHODS

Newly transplanted in-patients (n = 49) underwent hip radiographs and magnetic resonance imaging (MRI) a mean of 17.0+/-4.3 (range 8-29) days after renal transplantation. For the 48 patients without evidence of prevalent osteonecrosis, imaging at a mean of 5.9+/-0.8 (range 4.8-8.7) months after renal transplantation was graded for presence/absence of femoral head osteonecrosis by two blinded radiologists. Sociodemographic and disease characteristics of patients were compared to identify potential associations with incident osteonecrosis.

RESULTS

At 6-month follow-up, only two patients (4%) had osteonecrosis of the femoral head (three hips). The two primary radiologists had excellent agreement between osteonecrosis diagnosis (kappa coefficient=0.78). Both cases of a definite MRI diagnosis of osteonecrosis occurred in patients who were in the highest tertile of glucocorticoid dosage.

CONCLUSION

Osteonecrosis was uncommon among a prospective cohort of renal transplant recipients within 6 months after engraftment.

The treatment of glucocorticoid-induced osteoporosis

Glucocorticoid use results in an increase risk for fractures. Over the past 10 years, we have a greater understanding of the epidemiology, pathophysiology, prevention and treatment of glucocorticoid induced osteoporosis. This article reviews these recent findings and selective practice guidelines.

Metabolic bone disease in inflammatory bowel disease

Osteoporosis is associated with a high morbidity rate and is a risk factor for fractures. Patients with inflammatory bowel disease are at increased risk of developing osteopenia and osteoporosis. Corticosteroid use, malnutrition, and proinflammatory cytokines are unique risk factors for bone loss in ulcerative colitis and Crohn disease. Bone mineral density is assessed by dual-energy X-ray absorptiometry and reported as a T score or number of standard deviations away from the mean. A T score < 1 SD below the mean is normal, 1 to 2.5 SD below the mean is consistent with osteopenia, and greater than 2.5 SD below the mean is defined as osteoporosis. Treatment includes a combination of basic preventative measures, for example, weight-bearing exercise, calcium, vitamin D, and pharmacologic agents, (e.g., bisphosphonates).

Glucocorticoids induce glutamine synthetase expression in human osteoblastic cells: a novel observation in bone

Glucocorticoids have marked effects on bone metabolism, and continued exposure of skeletal tissue to excessive amounts of these steroids results in osteoporosis. Therefore, in the present proteomic study, we characterized the potential effects of glucocorticoids on protein expression in human osteoblastic cells. Using two-dimensional gel electrophoresis and mass spectrometry, we identified an increased expression of glutamine synthetase (GS) in dexamethasone (Dex)-treated human MG-63 osteosarcoma cells. GS is an enzyme catalyzing the conversion of glutamate and ammonia to glutamine. Intracellular and extracellular glutamate levels may be important in cell signalling mediated by glutamate transporters and receptors which have recently been found in bone cells. The induction of GS protein by Dex was accompanied by an increase in mRNA level and enzyme activity. Dex induction of GS was also mediated by glucocorticoid receptors (GRs) because it was blocked by the GR antagonist RU-38486. In addition, Dex induction of GS expression was partially blocked by cyclohexamide indicating that it at least partly required new protein synthesis. GS induction by Dex was not associated with apoptosis as determined by Bax/Bcl-2 ratio and DNA staining. In addition to MG-63 cells, Dex induction of GS was also observed in human G-292 osteosarcoma cells as well as conditionally immortalized human preosteoblastic (HOB-03-C5) and mature osteoblastic (HOB-03-CE6) cells. However, in two other human osteosarcoma cell lines, SaOS-2 and U2-OS, GS expression was not affected by Dex. This observation may be explained by the lower levels of GR protein in these cells. In summary, this is the first report of the regulation of GS expression by glucocorticoids in bone cells. The role of GS in bone cell metabolism and glucocorticoid action on the skeleton is not yet known, but as a modulator of intracellular glutamate and glutamine levels, it may have an important role in these processes.

Evaluation of bone mineral density of the peripheral skeleton in pre- and postmenopausal women with newly diagnosed endogenous Cushing's syndrome

OBJECTIVE

Cushing's syndrome (CS) is a well recognized cause of bone loss. Although many previous studies have shown decreased bone mineral density (BMD) in the lumbar spina and proximal femur of patients with endogenous CS, so far, the data estimating BMD in their peripheral skeleton are sparse. The aim of the present study was to evaluate BMD in the forearm and heel of women with newly diagnosed CS and to investigate its possible correlation with serum osteocalcin (BGP) and 24-hour urinary free cortisol levels (UFC).

PATIENTS AND METHODS

BMD in the forearm (distal and ultradistal area) of 29 (13 premenopausal and 16 postmenopausal) women with newly diagnosed CS (18 with pituitary adenoma, 10 with adrenal tumor and 1 with ectopic) was measured by dual x-ray absorptiometry (DEXA) and was compared with BMD of 29 age, body mass index (BMI)- and oestrogen status matched healthy controls. Furthermore, in 18 (9 premenopausal and 9 postmenopausal) of the above patients (14 with pituitary adenoma, 5 with adrenal tumor and 1 with ectopic) broadband ultrasound attenuation (BUA) by quantitative ultrasound (QUS) of the heel was estimated and 18 age-, BMI- and oestrogen status matched healthy women served as controls. In all the patients serum BGP and UFC were measured at the time of diagnosis of CS.

RESULTS

Compared to their matched controls, BMD in the forearm and BUA values in the heel did not differ in the premenopausal women with CS, while in the postmenopausal group BMD in the forearm was decreased (P < 0.05) but not BUA. Apart from a weak negative correlation between serum BGP and BMD in the ultradistal site of the forearm in premenopausal women (P = 0.05), serum BGP and UFC did not show significant correlation with BMD or BUA.

CONCLUSIONS

BMD in the forearm is reduced only in postmenopausal women with newly diagnosed endogenous CS, while BUA in the heel is unaffected in both pre- and postmenopausal patients. Moreover, serum BGP and UFC do not seem to be relevant markers for assessing bone loss in the peripheral skeleton at the time of diagnosis of hypercortisolemia.

Disorders associated with acute rapid and severe bone loss

We describe a constellation of bone diseases characterized by the common feature of acute, rapid, and severe bone loss accompanied by dramatic fracture rates. These disorders are poorly recognized, resulting mainly from systemic diseases, frailty, immobilization, and immunosuppressive drugs, such as glucocorticoids and the calcineurin inhibitors. The opportunity to prevent or treat fractures is commonly missed because they are often not detected. Ideally, patients need to be identified early and preventative therapy initiated promptly to avoid the rapid bone loss and fractures. The most effective therapy at present seems to be the bisphosphonates, particularly when bone resorption is predominant. However, more severe forms of bone loss that result from an osteoblastic defect and reduced bone formation may benefit potentially more from newer anabolic agents, such as recombinant human parathyroid hormone (rhPTH).

Dexamethasone enhances osteoclast formation synergistically with transforming growth factor-beta by stimulating the priming of osteoclast progenitors for differentiation into osteoclasts

Long-term administration of glucocorticoids (GCs) causes osteoporosis with a rapid and severe bone loss and with a slow and prolonged bone disruption. Although the involvement of GCs in osteoblastic proliferation and differentiation has been studied extensively, their direct action on osteoclasts is still controversial and not conclusive. In this study, we investigated the direct participation of GCs in osteoclastogenesis. Dexamethasone (Dex) at <10(-8) M stimulated, but at >10(-7) M depressed, receptor activator of NF-kappaB ligand (RANKL)-induced osteoclast formation synergistically with transforming growth factor-beta. The stimulatory action of Dex was restricted to the early phase of osteoclast differentiation and enhanced the priming of osteoclast progenitors (bone marrow-derived monocytes/macrophages) toward differentiation into cells of the osteoclast lineage. The osteoclast differentiation depending on RANKL requires the activation of NF-kappaB and AP-1, and the DNA binding of these transcription factors to their respective consensus cis-elements was enhanced by Dex, consistent with the stimulation of osteoclastogenesis. However, Dex did not affect the RANKL-induced signaling pathways such as the activation of IkappaB kinase followed by NF-kappaB nuclear translocation or the activation of JNK. On the other hand, Dex significantly decreased the endogenous production of interferon-beta, and this cytokine depressed the RANKL-elicited DNA binding of NF-kappaB and AP-1, as well as osteoclast formation. Thus, the down-regulation of inhibitory cytokines such as interferon-beta by Dex may allow the osteoclast progenitors to be freed from the suppression of osteoclastogenesis, resulting in an increased number of osteoclasts, as is observed in the early phase of GC-induced osteoporosis.

Glucocorticoid treatment of ovariectomized sheep affects mineral density, structure, and mechanical properties of cancellous bone

Thus far, orthopedic research lacks a suitable animal model of osteoporosis. In OVX sheep, 6 months of steroid exposure reduced bone density and mechanical competence. Bone properties and bone formation did not recover for another 6 months. Therefore, steroid-treated OVX sheep may serve as a large animal model for osteopenic bone.

INTRODUCTION

The purpose of this study was to explore the effects of glucocorticoid treatment on cancellous bone density, microarchitecture, biomechanics, and formation of new bone.

MATERIALS AND METHODS

Sixteen ovariectomized merino sheep received either a 6-month glucocorticoid treatment (GLU; 0.45 mg/kg methylprednisolone) or were left untreated (control). Cancellous bone biopsy specimens from the tibia were harvested 6 months after ovariectomy. After 12 months, the animals were killed, and biopsy specimens were obtained from the contralateral tibia and the lumbar spine. All biopsy specimens were scanned for apparent bone mineral density by peripheral quantitative computed tomography (pQCT) and tested mechanically in uniaxial compression. Three-dimensional bone reconstructions were obtained by microcomputed tomography. Formation of new bone was analyzed using histologies of the femoral condyles.

RESULTS

After 6 months, mineral density (-19%) and mechanical competence (-45%) were reduced by glucocorticoid treatment (p < 0.1). BV/TV (-21%; p < 0.01) and trabecular thickness (-20%; p = 0.01) declined, whereas BS/BV increased (24%; p = 0.01). After 12 months, mineral density (-33%) and mechanical properties (-55%) were reduced even more profoundly (p < 0.05). Also, the structural parameters (BS/BV and Tb.Th.) still seemed to be affected by glucocorticoid treatment (p < 0.05). New bone formation, assessed by measurement of osteoid surface, was markedly reduced (-63%, p < 0.1) by glucocorticoid treatment. The differences between groups were generally more pronounced at the tibia and the femur than at the spine.

CONCLUSION

The effects of short-term high-dose steroid administration on bone mineral in this animal model were comparable with those observed in humans after long-term corticoid treatment. Reduction in bone quality and bone formation rate persisted after the cessation of steroid administration. Glucocorticoid treatment of ovariectomized sheep may therefore serve as a large animal model for steroid-induced osteopenia.

Lovastatin inhibits adipogenic and stimulates osteogenic differentiation by suppressing PPARgamma2 and increasing Cbfa1/Runx2 expression in bone marrow mesenchymal cell cultures

The mechanism whereby lovastatin can counteract steroid-induced osteonecrosis and osteoporosis is poorly understood. We assessed the effect of lovastatin on a multipotential cell line, D1, which is capable of differentiating into either the osteoblast or the adipocyte lineage. The expression of bone cell and fat cell transcription factors Cbfa1/Runx2 and PPARgamma2, respectively, were determined. 422aP2 gene expression was analyzed. Osteocalcin promoter activity was measured by cotransfecting the cells with the phOC-luc and pSV beta-Gal plasmids. Lovastatin enhanced osteoblast differentiation as assessed by a 1.8x increase in expression of Cbfa1/Runx2 and by a 5x increase in osteocalcin promoter activity. Expression of PPARgamma2 was decreased by 60%. By enhancing osteoblast gene expression and by inhibiting adipogenesis, lovastatin may shunt uncommitted osteoprogenitor cells in marrow from the adipocytic to the osteoblastic differentiation pathway. Future evaluation of lovastatin and other lipid-lowering drugs will help determine their potential as therapeutic agents for osteonecrosis and osteoporosis.

Effects of 4-year treatment with once-weekly clodronate on prevention of corticosteroid-induced bone loss and fractures in patients with arthritis: evaluation with dual-energy X-ray absorptiometry and quantitative ultrasound

The aim of this placebo-controlled study was to determine whether once-weekly clodronate could prevent osteoporosis in patients with arthritis at the start of corticosteroid therapy. One hundred sixty-three patients, 18 to 90 years of age, with rheumatoid or psoriatic arthritis, were randomly assigned to receive either clodronate (100 mg im/week) plus calcium and vitamin D (1000 mg and 800 UI, respectively) or calcium and vitamin D alone. Patients had started therapy with prednisone or its equivalent within the previous 100 days and had bone mineral density <2.5 SD below mean young normal values at the lumbar spine or femoral neck. The primary outcome was the difference between the two treatment groups at months 12, 24, 36, and 48 in the mean percentage change from baseline in the bone mineral density of the lumbar spine, femur (neck and total), and total body. Secondary measurements included changes in the stiffness index evaluated by ultrasound measurements and the rate of new vertebral fractures. The bone density and stiffness did not change significantly in the clodronate plus calcium and vitamin D group, whereas it declined significantly in the calcium plus vitamin D group. The difference between treatment groups at 48 months in the mean change from baseline was 8.78 +/- 1.4% for the lumbar spine (P < 0.01), 7.31 +/- 1.12% for the femoral neck (P < 0.01), 7.92 +/- 1.93% for the trochanter (P < 0.01), 8.39 +/- 1.80% for total femur (P < 0.01), 6.94 +/- 1.09% for total body (P < 0.01), and 9.38 +/- 2.21% for stiffness of os calcis (P < 0.01). Depending on the skeletal regions evaluated, 85 to 98% of patients treated with clodronate had a densitometric change lower than the lowest significant densitometric difference. One hundred percent of patients treated with calcium plus vitamin D had a densitometric decrease greater than the lowest significant difference. The relative risk of vertebral fractures and multiple vertebral fractures in the clodronate group compared to the calcium plus vitamin D group was 0.63 (0.35-0.98, 95% CI) and 0.25 (0.15-0.91, 95% CI), respectively. We concluded that pulsatory administration of im clodronate once weekly is a safe therapy for preventing corticosteroid induced osteoporosis in patients with arthritis.

[Steroid induced osteoporosis: prevention and treatment]

PURPOSE

Corticosteroid induced osteoporosis (CIO) is the most frequent complication of long-term corticosteroid therapy, and the most frequent cause of secondary osteoporosis. New data from biological, epidemiological and therapeutic studies provide basis for optimal management of this bone disease.

MAIN POINTS

Corticosteroids are responsible for both quantitative and qualitative deleterious effects on bone, through their effect on bone cells, mainly on osteoblasts (with both a decrease in osteoblast activity and an increase in apoptosis). Epidemiological studies have shown an increased risk of fractures related to CIO, even for low doses, and during the first 6 months of treatment. Relative risk is 1.3 and 2.6 for peripheral and vertebral fractures respectively. Bone mineral density, measured by dual-energy X-ray absorptiometry, is decreased at spine and hip; the risk of fracture is higher in CIO as compared to post-menopausal osteoporosis, for a similar bone density. Prevention of CIO needs the use of the minimal efficacious dose, and treatment of calcium, vitamin D and gonadal hormones insufficiencies. Patients at risk of fracture, as post-menopausal women with prevalent fractures, should receive a bisphosphonate.

PERSPECTIVE

It may be possible to reduce the fracture risk in patients on long-term corticosteroid therapy.

Long-term follow-up of bone mineral density in Addison's disease

BACKGROUND AND AIMS

There is conflicting evidence regarding the long-term effects of long-term glucocorticoid replacement therapy (GRT) on bone mineral density (BMD) in patients with chronic adrenal insufficiency. Our aim was to evaluate bone turnover and changes in BMD in patients on GRT.

PATIENTS AND METHODS

We have studied 25 subjects (six men, 19 women; aged 62.4 +/- 11.3 years, duration of disease 21.7 +/- 11.7 years, fasting cortisol 63 +/- 36 nmol/l) on GRT (hydrocortisone 30 mg/day or prednisone 7.5 mg/day). BMD was assessed at the lumbar spine (LS; L2-L4), proximal femur (PF) and ultra distal radius (UR) by dual energy X-ray absorptiometry (DXA). The rates of bone loss were calculated using previous DXA measurements at the LS (48 and 60 months earlier). Serum calcium, phosphate alkaline phosphatase (ALP), bone ALP, serum osteocalcin (BGP), intact parathyroid hormone (PTH) and 25(OH) vitamin D were also measured.

RESULTS

BMD [Z-score; 95% confidence interval (95% CI)] was normal at the LS: (-1.15-+0.07); PF: (-0.90-+0.22) and UDR (-0.77-+0.36). No significant differences were found according to the type of replacement therapy or sex. No significant bone loss (g/cm2; 95% CI) was detected at the LS: (-0.021-+0.023). Fifty-six per cent of patients met osteoporotic criteria; a greater proportion of patients treated with prednisone had osteoporosis compared with those an hydrocortisone. All bone markers were in their normal ranges.

CONCLUSIONS

Patients on long-term therapy do not show accelerated bone loss at the lumbar spine. Nevertheless, a considerable proportion of patients, mainly those treated with prednisone, showed densitometric osteoporosis.

Generation of innovative anti-inflammatory and anti-arthritic glucocorticoid derivatives that release NO: the nitro-steroids

Addition to the prednisolone structure of a chemical moiety (linker+nitric ester) that releases NO species yielded a novel glucocorticoid (nitro-prednisolone or NCX-1015) with enhanced anti-inflammatory activities. Nitro-prednisolone was much more potent than prednisolone and the derivative devoid of the nitric ester in an acute peritonitis model (higher impact on neutrophil migration and soluble mediator generation) as well as in models of chronic inflammation (air-pouch granuloma and collagen II-induced arthritis). In the collagen II-induced arthritis model, NCX-1015 abrogated the plasma levels of a catabolite of cartilage and bone metabolism, indication of a disease modifying action. In an in vitro assay of bone resorption, NCX-1015 did not activate osteoclast activity, whereas prednisolone did. This lack of effect of NCX-1015 was chiefly due to NO. We propose that NCX-1015 is the prototype of a new class of glucocorticoids, the nitro-steroids, endowed with enhanced anti-inflammatory properties and reduced side effects. These and other experimental observations here reviewed may prompt the assessment of the clinical impact of the nitro-steroids on rheumatoid arthritis and inflammatory bowel disease.

A glucocorticoid-induced leucine-zipper protein, GILZ, inhibits adipogenesis of mesenchymal cells

Mesenchymal stem cells have the potential to differentiate into various cell lineages, including adipocytes and osteoblasts. The induction of adipocyte differentiation by glucocorticoids (GCs) not only causes the accumulation of fat cells in bone marrow, but also depletes the supply of osteoblasts for new bone formation, thus leading to osteoporosis. We have shown that a GC-induced leucine-zipper protein (GILZ) antagonizes adipocyte differentiation. GILZ binds to a tandem repeat of CCAAT/enhancer-binding protein (C/EBP) binding sites in the promoter of the gene encoding peroxisome-proliferator-activated receptor-gamma2 (PPAR-gamma2), and inhibits its transcription as a sequence-specific transcriptional repressor. We have also shown that ectopic expression of GILZ blocks GC-induced adipocyte differentiation. Furthermore, adipogenic marker genes (for example, those encoding PPAR-gamma2, C/EBP-alpha, lipoprotein lipase and adipsin) are also inhibited by GILZ. Our results reveal a novel GC antagonistic mechanism that has potential therapeutic applications for the inhibition of GC-induced adipocyte differentiation.

Glucocorticoid-induced osteoporosis

Therapeutic use of glucocorticoids can lead to many well-known adverse events. Of all potential serious side effects, glucocorticoid-induced osteoporosis (GIOP) is one of the most devastating complications of protracted glucocorticoid therapy in rheumatoid arthritis. GIOP is the most common form of drug-induced osteoporosis. Although much has been written about the association of glucocorticoids with bone disease among patients with chronic inflammatory conditions, many issues remain unsettled. This article focuses on areas of continued controversies, including the epidemiology and pathogenesis of GIOP, specification of a "safe" dose, methods for diagnosis of GIOP, and an evidence-based approach for GIOP prevention.

Is ultrasound of bone relevant for corticosteroid-treated patients? A comparative study with bone densitometry measured by DEXA

Corticosteroid treatment diminishes bone mass and alters bone quality. The objective was to evaluate bone in corticosteroid-treated patients and controls and in fractured and non-fractured patients treated with corticosteroids using both X-ray densitometry (DEXA) and ultrasound. We evaluated 34 women aged 58 +/- 14 years (X +/- SD), who had been on long-term low dose prednisone therapy for at least 6 months, and who had never received specific treatment for osteoporosis. Bone mineral density of total skeleton (TS), lumbar spine (LS), femoral neck (FN), and vertebral morphometry (MXA) were measured by DEXA. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness were measured using an Achilles Plus system. Forty-two healthy women served as controls. Both densitometric and ultrasound parameters in the patients were significantly diminished compared with controls: TS: P < 0.002, LS: P < 0.025, FS: P < 0.005, Stiffness: P < 0.001, BUA: P < 0.002 and SOS: P < 0.002. The percentage of patients with a Z score below -2 was higher in Stiffness and BUA: 38% and 47%, respectively, compared with a range of 16-24% in the other parameters (P < 0.05 BUA vs. DEXA measurements). Eleven patients with previous bone fracture had values lower than the non-fractured patients, both according to DEXA and ultrasound measurements, but the difference was only significant for BUA (P < 0.02). BUA of the calcaneus was more effective in detecting the specific skeletal alterations and fracture risk of the group of patients receiving chronic corticosteroid treatment.

[Cortisone therapy today]

Five decades of experimental and clinical experience have changed corticoid therapy thoroughly. Corticoides have two modes of action. The first is a genomic effect through which anti-inflammatory proteins are formed which inhibit pro-inflammatory cytokines. This effect is initiated even by small doses, but is of late onset. The use of high doses initiates non-genomic effects through alterations of the cell membrane; these effects are found early after initiation of treatment. The risk of adverse corticoid effects are extremely rare when modern application forms and therapy regimens are used: Very high doses for a short time in case of acute states of illness, very low doses in long-term therapy of chronic illnesses, and the use of topical substances wherever this is possible. As for the dose regimen, one should start with an initial dose which suffices to treat the acute state, and subsequently reduce the dosage after the first positive results are obtained. In long-term therapy a daily dose of 5 mg prednisolone should not be exceeded; usually even lower doses are sufficient. These very low doses can only be reached by reducing in steps of one half to one milligram over very long periods of time. During long-term therapy osteoporosis prophylaxis is mandatory. Due to these new therapeutic concepts treatment of rheumatoid arthritis with corticoids is experiencing a revival. Low-dose corticoid therapy is of lower risk than nonsteroidal antirheumatic treatment and slows down disease progression, i.e. joint destruction is significantly inhibited. Corticoids have also undergone a new development in the treatment of asthma. Previously used only in acute systemic therapy, they have now been established in basic therapy, i.e. long term therapy using special topic applications.

Phenotypic effects of continuous or discontinuous treatment with dexamethasone and/or calcitriol on osteoblasts differentiated from rat bone marrow stromal cells

Osteoblasts are target cells for glucocorticoids and calcitriol, and their phenotype is greatly modified by these hormones. We investigated the effect of continuous or discontinuous hormonal exposure to osteoblasts derived from rat bone marrow stromal cells in long-term subcultures. Stromal cells were grown in primoculture in presence of dexamethasone (dex), but in following subcultures, dex and/or calcitriol were added just after seeding or after a 7-day hormone-free period. Cell proliferation, alkaline phosphatase (ALP) histochemical staining, and enzymatic bioactivity measurement, osteocalcin (OC), ALP and bone sialoprotein (BSP) mRNA expression were used to study the differential effect on osteoblastic phenotype of various conditions of treatment by dex and calcitriol. In primoculture, the osteoblastic differentiation was confirmed by the formation of calcified nodules and by strong expression of ALP, OC, and BSP mRNAs. In subcultures, proliferation of stromal cells was stimulated by dex and inhibited by calcitriol and by both hormones. Cell proliferation was not modified by hormonal lack during 7 days. Continuous hormonal treatment by dex strongly enhanced OC and BSP mRNAs, but apparently did not modified ALP mRNAs expression. Continuous treatment by calcitriol decreased ALP and the dex-induced BSP expression and stimulated the OC mRNAs level, strongly when associated with dex. The population of ALP+ cells and ALP bioactivity were strongly increased by dex, whereas calcitriol or both hormones decreased them. When the subcultures were undergone without hormonal treatment during 7 days, all osteogenic mRNAs strongly decreased even after hormonal recovery. Dex, calcitriol, and both hormones inhibited ALP mRNAs. OC messengers were only weakly detectable with both hormones. ALP+ cell population and ALP bioactivity were decreased after 14 days of hormonal treatment recovery. These results support that continuous presence of glucocorticoids appears as a major key for the permanent expression of the osteoblastic phenotype that is inhibited by calcitriol, in the rat bone marrow.

Cortisol inhibits acid-induced bone resorption in vitro

Metabolic acidosis increases urine calcium excretion without an increase in intestinal calcium absorption, resulting in a net loss of bone mineral. In vitro, metabolic acidosis has been shown to initially induce physicochemical mineral dissolution and then enhance cell-mediated bone resorption. Acidic medium stimulates osteoblastic prostaglandin E(2) production, which mediates the subsequent stimulation of osteoclastic bone resorption. Glucocorticoids are also known to decrease bone mineral density, and metabolic acidosis has been shown to increase glucocorticoid production. This study tested the hypothesis that glucocorticoids would exacerbate acid-induced net calcium efflux from bone. Neonatal mouse calvariae were cultured in acid (Acid; pH = 7.06 +/- 0.01; [HCO(3)(-)] = 10.6 +/- 0.3 mM) or neutral (Ntl; pH = 7.43 +/- 0.01; [HCO(3)(-)] = 26.2 +/- 0.5 mM) medium, with or without 1 microM cortisol (Cort), and net calcium efflux and medium prostaglandin E(2) (PGE(2)) levels and osteoclastic beta-glucuronidase activity were determined. Compared with Ntl, Cort alone decreased calcium efflux, medium PGE(2), and osteoclast activity; Acid led to an increase in all three parameters. The addition of Cort to Acid led to a reduction of calcium efflux, medium PGE(2) levels and beta-glucuronidase activity compared with Acid alone. There was a significant direct correlation between medium PGE(2) concentration and net calcium efflux (r = 0.944; n = 23; P < 0.0001), between osteoclastic beta-glucuronidase activity and net calcium efflux (r = 0.663; n = 40; P < 0.001), and between medium PGE(2) concentration and beta-glucuronidase activity (r = 0.976; n = 4; P < 0.01). Thus, in vitro cortisol inhibits acid-induced, cell-mediated osteoclastic bone resorption through a decrease in osteoblastic PGE(2) production. These results suggest that the osteopenia observed in response to metabolic acidosis in vivo is not due to an increase in endogenous cortisol production.

Osteoporosis in men: pathophysiology, evaluation, and therapy

Osteoporosis is a serious health problem for men. An advance in our understanding of the pathophysiology and treatment of this disorder has resulted in the possibility of a gender-specific approach to screening, diagnosis, and treatment. Here we review the data on osteoporosis in men, discuss controversies regarding whom to screen, whom to treat, and how to treat. Recent treatment data as they relate to men are reviewed, and a clinical treatment algorithm is presented.

Glucocorticoid use in rheumatoid arthritis

More than 50 years after their discovery, glucocorticoids continue to be a mainstay of treatment for many patients with rheumatoid arthritis (RA). Although the short- and moderate-term efficacy of glucocorticoids in RA is seldom debated, increasing evidence favors a disease-modifying role of glucocorticoids. Despite renewed enthusiasm based on this newer long-term data, glucocorticoid use is marred substantially by the potential for many serious adverse events. Glucocorticoid-induced osteoporosis is one of the most predictable and serious complications for many chronic and some acute users. The correct identification of patients at high risk for bone complications and the institution of appropriate preventive measures may partially attenuate this adverse outcome.

Glucocorticoids inhibit cell cycle progression in differentiating osteoblasts via glycogen synthase kinase-3beta

Differentiating osteoblasts in culture undergo a commitment stage, during which cobblestone-like cells grow to high density past confluency. In contrast to earlier proliferative stages, the cell cycle during this commitment stage is inhibited by glucocorticoids (GC). Chronic GC treatment also impedes mineral deposition if steroid administration commences early enough during commitment. This study defines a role for glycogen synthase kinase-3beta (GSK3beta) and its target, c-Myc, in the GC-sensitive osteoblast persistent cell cycle. c-Myc levels decreased as cells reached confluence, but then increased during growth to high density. GC administration at this stage resulted in down-regulation of c-Myc. This was accompanied by GC-mediated attenuation of GSK3beta Ser(9) inhibitory phosphorylation and increased GSK3beta kinase activity. Down-regulation of c-Myc was attributable to enhanced Thr(58) phosphorylation, leading to accelerated degradation. In contrast, GC did not inhibit the c-Myc synthesis rate or the level of beta-catenin, a transcriptional coactivator of c-myc. The attenuated cell cycle and the reduced c-Myc level were returned to control levels by specific inhibition of GSK3beta using lithium chloride. These results suggest that tonal GSK3beta repression at the cobblestone stage of osteoblast differentiation permits osteoblast growth to high density. GC interfere with this growth-permissive axis by GSK3beta activation, resulting in c-Myc down-regulation and impediment of the G(1)/S cell cycle transition.

Dual energy X-ray absorptiometry outcomes in male COPD patients after treatment with different glucocorticoid regimens

STUDY OBJECTIVES

To compare bone mineral density (BMD) outcomes of patients who received continuous oral systemic glucocorticoids (GCs) with BMD outcomes of patients who received multiple GC courses, oral or IV.

DESIGN

Cross-sectional study.

PARTICIPANTS

Eighty-six white men with COPD selected from the outpatient clinic for pulmonary diseases.

INTERVENTION

Data analysis from medical records, bone densitometry, and pulmonary function tests of consecutive selected patients. Inclusion period into the study was exactly 1 year.

MEASUREMENTS AND RESULTS

Ten patients received oral prednisolone daily (group 1). Eleven patients were treated for several exacerbations with multiple systemic prednisolone courses, up to a period of 2 weeks per course, with a cumulative dose of > or = 1,000 mg (group 2). Likewise, 28 patients were treated with multiple systemic prednisolone courses, but with a cumulative dose < 1,000 mg (group 3). Thirty-seven patients were never treated with systemic prednisolone, and partly with inhaled corticosteroids (ICS) [group 4]. All groups were balanced for age and pack-years of smoking. In group 2, body mass index (BMI) and FEV(1) were lowest and hyperinflation was highest. The cumulative systemic prednisolone dose was highest in group 1, irrespective of the additional ICS treatments. Dual energy x-ray absorptiometry scanning of the lumbar spine, total hip, and femoral neck regions revealed a T score < or = 2.5 SD in 27 patients (31%), 31 patients (36%), and 34 patients (40%), respectively. BMD outcomes at any site were lower in patients receiving multiple systemic prednisolone courses > 1,000 mg, cumulatively (group 2), compared to the other groups, and these values were (mean +/- 1 SD) 0.759 +/- 0.238 g/cm(2), 0.683 +/- 0.115 g/cm(2), and 0.686 +/- 0.125 g/cm(2), respectively (p < 0.0001). Multivariate regression analysis revealed a correlation between the cumulative dose of prednisolone in group 2 and BMD of the lumbar spine (adjusted r = 0.48; p < 0.01). At the total hip and femoral neck regions, only a correlation between BMI and BMD was observed (adjusted r = 0.65 and 0.58, respectively; p < 0.0001 for both sites).

CONCLUSIONS

Despite a far lower cumulative GC dose in comparison with patients treated with systemic corticosteroids continuously, after adjusting for BMI and lung function, osteoporosis of the lumbar spine was most frequent in patients receiving > 1,000 mg of prednisolone cumulatively, administered in multiple courses for the treatment of exacerbations of COPD.