Glucocorticoid decreases circulating osteoprotegerin (OPG): possible mechanism for glucocorticoid induced osteoporosis

Bone Health in Paediatric Inflammatory Bowel Disease

Paediatric inflammatory bowel disease (IBD) is often complicated by bone loss resulting in an increased risk of fractures and impaired quality of life. Underlying inflammation, nutritional deficiencies and glucocorticoid therapy are some of the factors contributing to secondary osteoporosis in IBD. Optimising nutrition, dietary supplementation and timely screening are essential in preventing bone loss. Bisphosphonate therapy remains the cornerstone of medical management of osteoporosis. This review explores the various mechanisms contributing towards poor bone health in IBD and the recent advances in diagnostic and preventive approaches along with updates in management strategies.

Stimulation of osteoclast formation and bone resorption by glucocorticoids: Synergistic interactions with the calcium regulating hormones parathyroid hormone and 1,25(OH)2-vitamin D3

Osteoporosis is a significant health problem, with skeletal fractures increasing morbidity and mortality. Excess glucocorticoids (GC) represents the leading cause of secondary osteoporosis. The first phase of glucocorticoid-induced osteoporosis is increased bone resorption. In this Chapter, in vitro studies of the direct glucocorticoid receptor (GR) mediated cellular effects of GC on osteoclasts to affect bone resorption and indirect effects on osteoblast lineage cells to increase the RANKL/OPG ratio and stimulate osteoclastogenesis and bone resorption are reviewed in detail, together with detailed descriptions of in vivo effects of GC in different portions of the skeleton in research animals and humans. Brief sections are devoted to contrasting functions of GC in osteonecrosis, vitamin D formation, in vitro and in vivo bone resorptive actions dependent on vitamin D receptor and vitamin D toxicity, as well as the molecular basis of GR action. Included are also more detailed assessments of the interactions of GC with the major calcium regulating hormones, 1,25(OH)₂-vitamin D3 and parathyroid hormone, describing the in vitro increases in RANKL/OPG ratios, osteoclastogenesis and synergistic bone resorption that occurs when GC is combined with either 1,25(OH)₂-vitamin D3 or parathyroid hormone. Additionally, a molecular basic for the synergistic interaction of GC with 1,25(OH)₂-vitamin D3 is provided along with a suggested molecular basic for the interaction between GC and parathyroid hormone.

Osteoprotegerin changes in saliva and serum of patients with knee osteoarthritis

OBJECTIVE

The scope of this study was to assess salivary and serum osteoprotegerin (OPG) levels in knee osteoarthritis (OA).

METHODS

Serum and saliva OPG levels of 30 knee OA and 30 matched healthy controls in this cross-sectional study was assessed by ELISA. Knee pain was assessed by WOMAC. Data were analyzed by Student's t-test, Spearman correlation test and ROC.

RESULTS

The mean serum but not saliva OPG level was lower in knee OA than that of the healthy group. WOMAC negatively correlated with serum OPG (r=-0.501; P=0.000). The serum OPG cutoff value was 237.5pg/ml for the diagnosis of knee OA.

CONCLUSIONS

As serum OPG was lower in knee OA and negatively correlated with WOMAC, it seems that detection of OPG in serum but not in saliva may be a probable marker to the diagnosis of knee OA.

KEY MESSAGES

Osteoprotegerin decreases in knee osteoarthritis.

Effect of vitamin K2 and vitamin D3 on bone mineral density in children with acute lymphoblastic leukemia: a prospective cohort study

OBJECTIVES

Current treatment protocols in acute lymphoblastic leukemia (ALL) are associated with high remission rates and long life expectancy, enhancing the importance of quality of life and prevention of treatment-related complications in patient care. As osteoporosis is a frequent complication in patients under chemotherapy, we investigated the effect of vitamin K2 (100 mcg menaquinone-7) and vitamin D3 (10 mcg calcitriol) on bone metabolism in children with ALL.

METHODS

Twenty-nine consecutive patients recently diagnosed with B precursor ALL (B-ALL) and treated according to the Turkish Acute Lymphoblastic Leukemia Berlin Frankfurt Münster 2000 protocol were randomly assigned into study and control groups. The study group (n=15, M/F: 8/7, age 1-14.5 years, mean 6.5 years) received vitamin K2 and vitamin D3 with their chemotherapy, while the control group (n=14, M/F 9/5, age 2-17 years, mean 7.1 years) received chemotherapy only. Serum calcium, phosphorus, magnesium, alkaline phosphatase, bone-specific alkaline phosphatase, uncarboxylated osteocalcin (ucOC), tartrate resistant acid phosphatase 5b, carboxyl terminal procollagen propeptide (PICP), osteoprotegerin (OPG), and receptor activator nuclear kappa B ligand (RANKL) were measured and bone mineral density (BMD) was determined at baseline and first, second, third and sixth months.

RESULTS

The study group had higher serum OPG/RANKL ratio and lower ucOC levels compared to the control group at the first month; PICP levels were higher in the study group at second and third months.

CONCLUSIONS

These results suggest an early beneficial effect of the combination of vitamin K2 and vitamin D3 on BMD in ALL patients especially during the period of intensive steroid therapy in the first months.

IDO activation, inflammation and musculoskeletal disease

The IDO/kynurenine pathway is now established as a major regulator of immune system function. The initial enzyme, indoleamine 2,3-dioxygenase (IDO1) is induced by IFNγ, while tryptophan-2,3-dioxygenase (TDO) is induced by corticosteroids. The pathway is therefore positioned to mediate the effects of systemic inflammation or stress-induced steroids on tissue function and its expression increases with age. Disorders of the musculoskeletal system are a common feature of ageing and many of these conditions are characterized by an inflammatory state. In inflammatory arthritis and related disorders, kynurenine protects against the development of disease, while inhibition or deletion of IDO1 increases its severity. The long-term regulation of autoimmune disorders may be influenced by the epigenetic modulation of kynurenine pathway genes, with recent data suggesting that methylation of IDO may be involved. Osteoporosis is also associated with abnormalities of the kynurenine pathway, reflected in an inversion of the ratio between blood levels of the metabolites anthranilic acid and 3-hydroxy-anthranilic acid. This review discusses evidence to date on the role of the IDO/kynurenine pathway and the highly prevalent age-related disorders of osteoporosis and rheumatoid arthritis and identifies key areas that require further research.

Osteoprotegerin and Cardiovascular Events in High-Risk Populations: Meta-Analysis of 19 Prospective Studies Involving 27 450 Participants

Background Osteoprotegerin is a cytokine involved in bone metabolism as well as vascular calcification and atherogenesis. Although circulating osteoprotegerin levels are robustly associated with incident cardiovascular disease ( CVD ) in the general population, its relevance as a biomarker among populations at high CVD risk is less clear. Methods and Results Three independent reviewers systematically searched PubMed, EMBASE , and Web of Science to identify prospective studies that had recruited participants on the basis of having conditions related to high CVD risk. A total of 19 studies were eligible for inclusion, reporting on 27 450 patients with diabetes mellitus (2 studies), kidney disease (7 studies), preexisting heart disease (5 studies), or recent acute coronary syndromes (5 studies) at baseline. Over a mean follow-up of 4.2 years, 4066 CVD events were recorded. In a random-effects meta-analysis, the pooled risk ratio for CVD events comparing people in the top versus the bottom tertile of osteoprotegerin concentration was 1.30 (95% confidence interval, 1.12-1.50; P<0.001; I2=68.3%). There was evidence for presence of publication bias ( P value from Egger's test=0.013). Correction for publication bias using the trim-and-fill method reduced the risk ratio to 1.21 (95% confidence interval, 1.03-1.42; P<0.001). The risk ratios did not vary significantly by population type, geographical region, statistical adjustment, sample or assay type, age, sex, or length of follow-up. Conclusions In populations at high CVD risk, elevated circulating osteoprotegerin levels are associated with a higher risk for future CVD events. The magnitude of association appears weaker than in the general population.

Possible mechanisms of prednisolone-induced osteoporosis in zebrafish larva

Glucocorticoid-induced osteoporosis (GIOP) is a serious clinical bone disease that results from the long-term consumption of glucocorticoids or glucocorticoid-like drugs. Although many studies have attempted to determine the mechanisms of GIOP, they are still unclear. In this study, we established a zebrafish model of glucocorticoid-like drug-induced osteoporosis by treating larvae with prednisolone. We then quantified the expression of a selection of extracellular matrix (ECM)-, osteoblast-, and osteoclast-related genes. Our results showed that at 15 days post fertilization, zebrafish larvae treated with 25 μM prednisolone are a suitable model for GIOP, not only owing to the decrease in robust bone mass but also because of significant alterations in gene expression. The quantification of the expression of ECM-, osteoblast-, and osteoclast- related genes revealed that mmp9 and mmp13 were significantly upregulated and entpd5a, acp5a, and sost were significantly downregulated. These genes may be a target for future research into GIOP. Our study thus provides new insights into GIOP.

Multiparameter Analysis of Off-Target Effects of Dasatinib on Bone Homeostasis in Patients With Newly Diagnosed Chronic Myelogenous Leukemia

BACKGROUND

We assessed patients with chronic myelogenous leukemia (CML) for serum calcium (Ca), phosphate (PO4), bone alkaline phosphatase, N-telopeptide (NTx), osteoprotegerin (OPG) levels, and trabecular bone area (TBA) in bone marrow (BM) specimens before and after treatment with dasatinib. We identified a significant increase in percentage of TBA in postdasatinib BM (P = .022). This suggests that dasatinib therapy can increase TBA without significant changes in bone and mineral metabolism. Interferences with bone homeostasis and mineral metabolism have been described in patients receiving imatinib for CML or gastrointestinal stromal tumors. Dasatinib is a potent second-generation tyrosine kinase inhibitor designed to inhibit ABL and SRC kinases while also interfering with the c-Kit, platelet-derived growth factor receptor, and STAT5 pathways.

PATIENTS AND METHODS

We used a multiparameter approach to examine the off-target effects of dasatinib in 30 patients with CML treated between 2009 and 2012. We recorded serum Ca and PO4 levels, analyzed markers of bone formation (bone alkaline phosphatase/bone-specific alkaline phosphatase [BAP]) and bone resorption (NTx), measured OPG levels, and digitally analyzed changes in TBA in paired BM biopsy specimens before and after treatment. We correlated all findings with each other and with the results of conventional cytogenetic and molecular analyses.

RESULTS

We identified a significant increase in the percentage of TBA in postdasatinib BM biopsy specimens (P = .022) and noted a decrease in serum OPG levels in 75% of patients. Ca, PO4, BAP, and NTx levels remained steady, without significant changes. There was no correlation between biomarker levels, percentage of TBA, and/or cytogenetic or molecular response.

CONCLUSION

These findings suggest that dasatinib therapy (within the therapeutic range) can increase trabecular bone, without causing significant changes in bone and mineral metabolism. Nonetheless, monitoring of bone health and skeletal integrity should be included into the long-term management of patients treated with dasatinib to further enhance our understanding of its safety profile and its potential role as a treatment modality for other bone diseases.

Low Doses of Simvastatin Potentiate the Effect of Sodium Alendronate in Inhibiting Bone Resorption and Restore Microstructural and Mechanical Bone Properties in Glucocorticoid-Induced Osteoporosis

By using an experimental model of dexamethasone-induced osteoporosis we investigated the effects of different therapeutic schemes combining sodium alendronate (SA) and simvastatin on bone mineral and protein composition, microstructural and mechanical remodeling. Wistar rats were randomized into eight groups: G1: non-osteoporotic; G2: osteoporotic; G3, G4, and G5: osteoporotic+SA (0.2, 0.4, and 0.8 mg/kg, respectively); G6, G7, and G8: osteoporotic+SA (0.2, 0.4, and 0.8 mg/kg, respectively)+simvastatin (0.4, 0.6, and 1 mg/kg, respectively). Osteoporosis was induced by dexamethasone (7 mg/kg, i.m.) once a week for 5 weeks. All treatments were administered for 8 weeks. Dexamethasone increased serum levels of alkaline phosphatase, calcium, phosphorus, and urea, especially in non-treated animals, which showed severe osteoporosis. Dexamethasone also induced bone microstructural fragility and reduced mechanical resistance, which were associated with a marked depletion in mineral mass, collagenous and non-collagenous protein levels in cortical and cancellous bone. Although SA has attenuated osteoporosis severity, the effectiveness of drug therapy was enhanced combining alendronate and simvastatin. The restoration in serum parameters, organic and inorganic bone mass, and mechanical behavior showed a dose-dependent effect that was potentially related to the complementary mechanisms by which each drug acts to induce bone anabolism, accelerating tissue repair.

Protecting Bone Health in Pediatric Rheumatic Diseases: Pharmacological Considerations

Bone health in children with rheumatic conditions may be compromised due to several factors related to the inflammatory disease state, delayed puberty, altered life style, including decreased physical activities, sun avoidance, suboptimal calcium and vitamin D intake, and medical treatments, mainly glucocorticoids and possibly some disease-modifying anti-rheumatic drugs. Low bone density or even fragility fractures could be asymptomatic; therefore, children with diseases of high inflammatory load, such as systemic onset juvenile idiopathic arthritis, juvenile dermatomyositis, systemic lupus erythematosus, and those requiring chronic glucocorticoids may benefit from routine screening of bone health. Most commonly used assessment tools are laboratory testing including serum 25-OH-vitamin D measurement and bone mineral density measurement by a variety of methods, dual-energy X-ray absorptiometry as the most widely used. Early disease control, use of steroid-sparing medications such as disease-modifying anti-rheumatic drugs and biologics, supplemental vitamin D and calcium, and promotion of weight-bearing physical activities can help optimize bone health. Additional treatment options for osteoporosis such as bisphosphonates are still controversial in children with chronic rheumatic diseases, especially those with decreased bone density without fragility fractures. This article reviews common risk factors leading to compromised bone health in children with chronic rheumatic diseases and discusses the general approach to prevention and treatment of bone fragility.

Gout increases risk of fracture: A nationwide population-based cohort study

There is still debate on whether high uric acid increases bone mineral density (BMD) against osteoporotic fracture or bone resorption caused by gout inflammation. This study aimed to evaluate whether gout offers a protective effect on bone health or not. We conducted a nationwide population-based retrospective cohort study to evaluate the association between gout history and risk factors of fracture.A retrospective cohort study was designed using the claim data from Longitudinal Health Insurance Database (LHID). A total of 43,647 subjects with gout and a cohort of 87,294 comparison subjects without gout were matched in terms of age and sex between 2001 and 2009, and the data were followed until December 31, 2011. The primary outcome of the study was the fracture incidence, and the impacts of gout on fracture risks were analyzed using the Cox proportional hazards model.After an 11-year follow-up period, 6992 and 11,412 incidents of fracture were reported in gout and comparison cohorts, respectively. The overall incidence rate of fracture in individuals with gout was nearly 23%, which was higher than that in individuals without gout (252 vs 205 per 10,000 person-years) at an adjusted hazard ratio of 1.17 (95% confidence interval = 1.14-1.21). Age, sex, and fracture-associated comorbidities were adjusted accordingly. As for fracture locations, patients with gout were found at significant higher fracture risks for upper/lower limbs and spine fractures. In gout patient, the user of allopurinol or benzbromarone has significantly lower risk of facture than nonusers.Gout history is considered as a risk factor for fractures, particularly in female individuals and fracture sites located at the spine or upper/lower limbs.

An experimental study to evaluate the antiosteoporotic effect of Panchatikta Ghrita in a steroid-induced osteoporosis rat model

Objective:

The study was conducted to develop the glucocorticoid-induced osteoporosis (GIO) model in Sprague-Dawley weanling rats using different doses of methylprednisolone (MP) and evaluate the antiosteoporotic effect of a classical ayurvedic formulation, Panchatikta Ghrita (PG), in this model.

Materials and Methods:

Institutional Animal Ethics Committee approval was obtained. Development of model was done by subcutaneous injection of 2 doses of MP (14 and 28 mg/kg/week) for 4 weeks in 21-day old weanlings. Following confirmation of the dose of MP that induced osteoporosis, the antiosteoporotic effect of PG was tested in this model in comparison to a known antiosteoporotic agent, alendronate. Both alendronate (2.9 mg/kg/day) and PG (1.35 g/kg/day) were administered orally 2 weeks after MP - 14 mg/kg/week injection and continued for 4 weeks. Serum and urine calcium and inorganic phosphate were analyzed at weekly intervals. Animals were sacrificed after 6 weeks, and femur bones were processed to measure bone hardness and elasticity and for histological studies.

Results:

Rats treated with MP - 14 mg/kg/week showed optimum osteoporotic effect with no mortality as compared to MP - 28 mg/kg/week; hence, this dose of MP was used further for the efficacy study. Osteoporotic rats treated with PG 1.35 g/kg showed increase in serum calcium and inorganic phosphate levels, whereas urine calcium and phosphate levels were significantly reduced. A significant decrease in a number of osteoclasts, whereas an increase in bone hardness and elasticity was observed as compared to diseased group demonstrating antiosteoporotic effect of PG.

Conclusion:

PG has an antiosteoporotic effect in GIO rat model.

Markers of bone remodeling are associated with arterial stiffness in renal transplanted subjects

BACKGROUND

Bone-vessel interaction in chronic renal failure remains poorly understood and could be driven by bone remodeling factors including osteoprotegerin (OPG), fibroblast growth factor 23 (FGF23), parathormone and vitamin D. Only few data are available in renal transplantation. The aim of this study was to investigate the relationship between bone remodeling factors and large artery function in renal transplant patients.

METHODS

89 renal transplant patients were enrolled in this cross-sectional study. Carotid to femoral pulse wave velocity (PWV) and central augmentation index (AIx) were determined as an estimation of large artery function. Blood samples were collected for measurement of vascular risk markers. Independent predictors were identified by multivariate linear regression through backward feature selection using Akaike's information criteria.

RESULTS

At multivariate analysis, age (p < 0.001) and systolic arterial pressure (p = 0.003) were significantly associated with PWV but not AIx. In addition, both elevated blood concentrations of 1.25(OH)2 vitamin D (p = 0.013) and OPG (p = 0.047) were still significantly related to high PWV.

CONCLUSIONS

These results underline that age and mean arterial pressure are the main determinants of PWV following renal transplantation. Among bone remodeling biomarkers, plasma OPG and active vitamin D were the strongest determinants of arterial stiffness.

Acute effects of glucocorticoids on serum markers of osteoclasts, osteoblasts, and osteocytes

The aim of this study was to investigate the acute effects of oral glucocorticoids in doses used in clinical practice on biochemical indices of the function of osteoclasts, osteoblasts, and osteocytes. In 17 adult patients suffering from various medical pathologies requiring systemic steroid therapy that were never before treated with glucocorticoids, glucocorticoid treatment was initiated (mean prednisolone equivalent dose of 23.1 ± 12.7 mg/day, range 10-50). Fasting morning serum concentrations of osteocalcin (OC), amino-terminal propeptide of type I procollagen (PINP), type 1 collagen cross-linked C-telopeptide (βCTX), soluble receptor activator of nuclear factor kappaB ligand (sRANKL), osteoprotegerin (OPG), sclerostin, Dickkopf-1 (Dkk-1), and high-sensitivity C-reactive protein (hsCRP) were measured at baseline and on three consecutive days. Significant reductions in serum OC, PINP, OPG, sclerostin, and hsCRP were observed during 96 h of glucocorticoid administration, while serum βCTX showed a significant percentual increase. A significant positive correlation was found between serum concentrations of Dkk-1 and βCTX after 96 h of treatment with glucocorticoids. A significant drop in serum sclerostin, OPG, and OC observed in this study may reflect the rapid glucocorticoid-induced apoptosis of osteocytes.

[Mechanisms and therapeutics of glucocorticoid-induced osteoporosis]

Mechanisms of glucocorticoid-induced osteoporosis (GIOP) are categorized into local and systemic effects. In the local mechanisms, direct inhibitory effect of glucocorticoid on bone formation is thought to be one of the important mechanisms of GIOP. In contrast, secondary hyperparathyroidism induced by negative balance of calcium due to inhibition of absorption and increase of excretion is an important systemic mechanism of GIOP. Other mechanisms of GIOP are also shown in this review. From clinical points of view, serum markers for evaluation of GIOP have been discussed. Osteocalcin, procollagen type I N-terminal peptide, and bone-specific alkaline phosphatase as markers of bone formation are decreased in GIOP. Collagen I N-terminal telopeptide and tartrate resistent acid phosphatase isoform 5b as markers of bone resorption are increased in GIOP. Clinical guidelines have recommended that bisphosphonate is the first choice for the treatment of GIOP. Teriparatide is recombinant human parathyroid hormone 1-34, which should be considered as a therapeutic option for those at high risk of bone fracture. Denosumab, an anti receptor activator of nuclear factor-β ligand approved as a drug for postmenopausal osteoporosis was also effective for GIOP in clinical trials.

Widespread negative response elements mediate direct repression by agonist-liganded glucocorticoid receptor

The glucocorticoid (GC) receptor (GR), when liganded to GC, activates transcription through direct binding to simple (+)GRE DNA binding sequences (DBS). GC-induced direct repression via GR binding to complex "negative" GREs (nGREs) has been reported. However, GR-mediated transrepression was generally ascribed to indirect "tethered" interaction with other DNA-bound factors. We report that GC-induces direct transrepression via the binding of GR to simple DBS (IR nGREs) unrelated to (+)GRE. These DBS act on agonist-liganded GR, promoting the assembly of cis-acting GR-SMRT/NCoR repressing complexes. IR nGREs are present in over 1000 mouse/human ortholog genes, which are repressed by GC in vivo. Thus variations in the levels of a single ligand can coordinately turn genes on or off depending in their response element DBS, allowing an additional level of regulation in GR signaling. This mechanism suits GR signaling remarkably well, given that adrenal secretion of GC fluctuates in a circadian and stress-related fashion.

Evolution of coronary artery calcifications following kidney transplantation: relationship with osteoprotegerin levels

We prospectively assessed the evolution of coronary artery calcification (CAC) and osteoprotegerin (OPG) levels after renal transplantation (RT). Eighty-three recipients were followed-up prospectively during 1 year. Blood was collected before (baseline) and after RT for determination of mineral metabolism parameters including OPG. CAC was measured by multidetector computed tomography at transplantation (baseline) and 1 year later. Progression of CAC was defined as a difference between the follow-up square-root transformed volume (SRV) and the baseline SRV >or= 2.5. By multivariate analysis, baseline OPG level, age and low LDL levels were significantly associated with baseline CAC. RT was accompanied by mineral metabolism improvement with a decrease of OPG from 955 [395-5652] to 527 [217-1818] pg/mL and parathyroid hormone from 94 [1-550] to 62 [16-410] pg/mL. Thirty-one percent of patients did not exhibit CAC at baseline. CAC diminished in 14.5%, stabilized in 59.2% and progressed in 26.3% of patients. Baseline CAC was associated with progression (OR 2.92 [1.02-8.36]). No significant association was found between OPG and CAC progression despite a higher baseline OPG level in progressors (1046 [456-3285]) vs. non-progressors (899 [396-5952] pg/mL). CAC at baseline, but not 1 year after RT, is independently associated with baseline OPG; posttransplant CAC progression is predicted by baseline CAC score.

Therapeutic implications of osteoprotegerin

Osteoprotegerin (OPG), a member of the tumor necrosis factor (TNF) receptor superfamily, contributes determinatively to the bone remodeling as well as to the pathogenetic mechanism of bone malignancies and disorders of mineral metabolism. There is additional evidence that OPG can promote cell survival by inhibiting TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. A number of recent in vitro, in vivo and clinical studies have defined the role of the RANK/RANKL/OPG pathway in skeletal and vascular diseases. These works were the milestone of the deep understanding of the mechanism of OPG. This review provides an overview of the potential innovative therapeutic strategies of OPG in metastatic breast and prostate carcinoma, multiple myeloma, postmenopausal osteoporosis, glucocorticoid-induced osteoporosis and rheumatoid arthritis. Special reference is given to the increasing evidence that RANKL and OPG may link the skeletal with the vascular system.

Low bone mineral density in adult patients with moderate to severe atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease commonly treated with topical corticosteroids. The inflammatory nature of this disorder and the use of topical corticosteroids represent potential risk factors for bone loss.

OBJECTIVES

The aim was to assess the prevalence of osteoporosis and osteopenia in adult patients with moderate to severe AD. In addition, the associations between topical/oral corticosteroid use and bone mineral density (BMD) and between disease activity and BMD were studied.

PATIENTS AND METHODS

We studied 125 adult patients with moderate to severe AD. Using dual-energy X-ray absorptiometry, BMD was measured at lumbar spine and hips. The cumulative dose of topical and oral corticosteroids was calculated from pharmacy prescription records. Lifestyle parameters were collected by a questionnaire. Biochemical parameters of bone metabolism and disease activity [serum concentration of thymus and activation-regulated chemokine (TARC) levels] were also measured.

RESULTS

Osteoporosis was documented in six patients (4.8%) and osteopenia in 41 patients (32.8%); 30.4% of the patients had a Z-score <or= -1 (low BMD), with more men (43.8%) than women (16.4%) affected. There was no significant association between low BMD and biochemical parameters of bone metabolism, serum TARC levels and cumulative dose of topical and oral corticosteroids during the 5 years prior to inclusion.

CONCLUSIONS

We document a Z-score <or= -1 in about one-third of predominantly male patients with moderate to severe AD, being independent of the cumulative dose of topical and corticosteroids used within 5 years prior to study. Whether the relatively high prevalence of low BMD is due to the cumulative dose of topical corticosteroids beyond 5 years prior to the study or the chronicity of the underlying inflammatory process or a combination of these, remains to be established.

Clinical potential of RANKL inhibition for the management of postmenopausal osteoporosis and other metabolic bone diseases

Osteoporosis affects millions of people worldwide, causing decreases in bone strength and a marked increase in fracture risk. Current therapies increase bone mineral density and reduce the risk of fractures, but dosing requirements are often considered inconvenient, and patient compliance with therapy is poor. This review will discuss recent discoveries in bone biology, which have demonstrated that the interaction of osteoprotegerin (OPG), receptor activator of nuclear factor--kappa B (RANK), and RANK ligand (RANKL) is critical for the regulation of bone remodeling. Collectively, these preclinical studies have shown that endogenous RANKL inhibition by OPG underlies the normal mechanism for maintaining the correct balance between bone resorption and bone formation. Multiple clinical trials are in progress to investigate the therapeutic potential of RANKL inhibition by denosumab, a fully human monoclonal anti-RANKL antibody, in the treatment of postmenopausal osteoporosis and other bone loss diseases. The results of these human trials will also be discussed.

Pathogenesis of calciphylaxis: Hans Selye to nuclear factor kappa-B

The clinical syndrome of calciphylaxis is characterized by arteriolar medial calcification, thrombotic cutaneous ischemia, necrotic skin ulceration, and a high mortality rate. This review integrates calciphylaxis risk factors with the molecular processes governing osseous and extraosseous mineralization. As the pathogenesis of calciphylaxis is better understood, targeted therapies aimed at disease prevention and reversal will follow.

Effects of the administration of corticosterone, parathyroid hormone, or both, and of their withdrawal, on rat bone and cartilage histomorphometric parameters, and on osteoprotegerin and RANKL mRNA expression and proteins

We have studied the effects of the treatment with corticosterone (CORT), parathyroid hormone (PTH), or both (CORT + PTH), and of their withdrawal (CORT-rec and CORT + PTH-rec), on the osteoprotegerin (OPG) and receptor activator of nuclear factor-kB ligand (RANKL) localization and expression and on histomorphometric parameters in primary and secondary spongiosa of rat femur and tibia metaphyses. In the secondary spongiosa of the CORT group, the bone remodeling and the OPG/RANKL mRNA ratio decreased. In the PTH group, the bone turnover and the structural and connectivity indices increased, and the OPG/RANKL mRNA ratio fell; this ratio rose, however, in the primary spongiosa. In the CORT + PTH group, remodeling values intermediate between those of the CORT and PTH groups, were detected in the secondary spongiosa, where OPG and RANKL mRNA rose. Return towards control values was found in the recovery groups. The Cartilage Growth Plate Width was reduced in the CORT and CORT + PTH groups and returned to normal values in the recovery groups, while it was not affected by PTH. Independently of treatments, both OPG and RANKL mRNA and proteins were co-localized in the same cartilage and bone cells and in several bone marrow cells. In conclusion, the catabolic effects induced by CORT treatment occur together with an OPG fall and a RANKL rise. In the PTH group in which the bone turnover increase, the OPG and RANKL mRNA expressions differ in the primary and secondary spongiosa, confirming that the bone tissue in these sites can have different metabolic trends.

Prevention and treatment of glucocorticoid-induced osteoporosis

Glucocorticoids continue to be used for many inflammatory diseases, and glucocorticoid-induced osteoporosis (GIOP) remains the most common secondary form of metabolic bone disease. Recent meta-analyses suggest that both active and native vitamin D can help maintain lumbar spine bone mineral density (BMD), particularly in patients receiving lower-dose glucocorticoid therapy. Recent randomized, controlled clinical trials have shown that oral bisphosphonates are superior to vitamin D in maintaining BMD and should be continued for as long as a person receives glucocorticoid treatment. Similar to the oral bisphosphonates, intravenous ibandronate has been shown to preserve BMD and also to significantly reduce vertebral fracture risk. Increasing evidence supports a role for parathyroid hormone to prevent or treat GIOP as well. Despite effective therapies, many at-risk patients fail to receive treatment for GIOP, and even among those who initiate treatment, half discontinue within 1 to 2 years. New approaches to evidence implementation are being tested to improve the quality of osteoporosis care and decrease fracture risk among long-term glucocorticoid users.

Advances in the diagnosis and treatment of osteoporosis

Although severely low bone density is relatively rare in the pediatric population, it can be a significant problem in many patients with chronic illness. As peak bone formation occurs during adolescence, it is crucial that pediatricians and other care providers for this patient population recognize the significance of attainment of adequate bone. Dietary intake of vitamin D and calcium should be optimized, and correction of underlying causes of poor bone density should occur whenever possible. Assessment of bone density is difficult, as each technology available has problems, and none of the technologies are well-associated with fracture risk in pediatric patients. Once diagnosis of severely low bone density is established, treatment options are limited and poorly studied. The benefits of bisphosphonate therapy appear to outweigh the risks in patients with low bone density and frequent fragility fractures, and it appears that most improvement with bisphosphonates occurs within the first 2 to 4 years. Evidence, however, is emerging that once off therapy, bone turnover remains decreased for at least several years. During that time, improvements in bone density are decreased. Many questions remain regarding duration of therapy with bisphosphonate therapy and the long-term effects on the children who receive this medication. Anabolic therapies may become important in the future, but there is currently extremely limited information regarding their use in pediatrics.

Renal transplantation decreases osteoprotegerin levels

Vascular calcifications are an important risk factor for cardiovascular mortality and morbidity in patients with chronic renal failure. Osteoprotegerin, a soluble decoy receptor for receptor activator NFkB ligand, has emerged as an independent predictive factor of atherosclerosis and vascular calcification in hemodialysis patients. Sparse data are available on the evolution of osteoprotegerin after renal transplantation. The aim of this study was to follow the evolution of serum osteoprotegerin levels and biochemical risk factors after renal transplantation. Forty patients were included. Blood samples for analysis were collected before and 3 months after renal transplantation. Besides the expected diminution in calcium-phosphate product, we have shown an early normalization of osteoprotegerin (10.05 +/- 4.77 pmol/L to 4.59 +/- 2.26 pmol/L). This study demonstrates that kidney transplantation improves this risk factor for vascular calcifications. However, these preliminary results should be confirmed and extended by the follow-up of vascular calcifications in the long term.

Osteoporosis in the elderly with chronic kidney disease

Considering the aging dialysis population of today, increasing our knowledge about the nature, diagnosis and the treatment of bone mineral density (BMD) problems in end-stage renal disease (ESRD) patients deserves more attention. Osteoporosis is basicly defined as a decrease in bone mass. Large epidemiological studies in general population have identified several risk factors for osteoporosis including advancing age, female gender, white race, decreased calcium intake, gastric acid suppression therapy, sedentary lifestyle, premature loss of gonadal function, decreased estrogen secretion, thin body habitus, decreased physical activity, cigarette smoking, alcohol abuse, excess glucocorticoid exposure, and possibly some genetic factors. Osteoporosis in ESRD patients is only a part of a wider spectrum of metabolic bone problems, namely uremic osteodystrophy. Therefore, its diagnosis, management and follow-up may differ from the general population and an individualization of diagnosis and definition for dialysis population may be necessary. However, standard diagnostic tools such as dual energy X-ray absorptiometry (DEXA) have been widely used for the assessment of bone mineral deficiency status in ESRD patients. Regardless of the methods, most of the studies are in concordance with a reduced BMD in HD and PD patients. Dialysis patients are known to be at increased risk for low-trauma fractures. Thinning of cortical bone, which is responsible for the largest contribution toward reduced bone mineral content in chronic renal failure results in increased fracture risk. In either normal population and dialysis patients, fracture risk is increased with age. But in dialysis patients, besides age, several other factors may also affect the degree of bone mineral deficiency, and age-BMD relationship may be blunted. Female sex, in hemodialysis patients is negatively associated with total hip BMD. While several studies have been unable to demonstrate any association between BMD and PTH levels, larger body size has been shown to have a significant positive effect on BMD in both hemodialysis and peritoneal dialysis patients. Although they have been used in small groups of chronic kidney disease (CKD) and ESRD patients, because of their potential nephrotoxicity and hypocalcemic effects, use of biphosphonates in renal patients is questionable. Currently, bone biopsy, in order to exclude adynamic bone disease is recommended before beginning treatment with bisphosphonates in chronic kidney disease and dialysis patients.

Glucocorticoid-Induced Osteoporosis: Mechanisms and Therapeutic Approach

GCs constitute a therapeutic class largely used in clinical medicine for the curative or supportive treatment of various conditions involving the intervention of numerous medical specialties. Beyond their favorable therapeutic effects, GCs almost invariably provoke bone loss and a rapid increase in bone fragility, with its host of fractures. Men and postmenopausal women constitute a preferential target for the bone complications of GCs. The premenopausal status is not, however, a shelter; bone loss also happens in young women who are on GCs. Exposure to GCs yields a fracture risk exceeding the risk conferred by a low BMD per se. Therefore, some reason exists to settle the BMD threshold for therapeutic intervention not at -2.5 T-scores but at -1.0 or -1.5 T-scores, even if no prospective randomized trial so far endorses that opinion. Nowadays, bisphosphonate therapy should be proposed to every patient at risk for fragility fracture, along with calcium and vitamin D supplementation. Studies of other therapeutic modalities (eg, promoters of bone formation) are in progress.

Vascular calcification and renal osteodystrophy relationship in chronic kidney disease

Cardiovascular disease and stroke account for 60-70% of all deaths in patients with end-stage renal disease (ESRD), at a risk that is 10-20-fold the age- and sex-matched general population. There is also increased coronary artery calcification and increased cardiovascular mortality in chronic kidney disease (CKD) and dialysis patients compared with the general population. Bone is similarly abnormal in CKD. There is an increased incidence of low bone mass and fractures in dialysis patients compared with the general population. Furthermore, a hip fracture in a dialysis patient is associated with a doubling of the mortality observed in nondialysis patients with a hip fracture. These two problems may be linked, as cross-sectional studies have demonstrated an inverse relationship between osteoporosis and coronary artery calcification in the general population and in ESRD patients. In vitro and ex vivo, there is clear evidence that vascular calcification is an active cell-mediated process, made worse by disorders of mineral metabolism. Many factors known to be associated with cardiovascular disease in CKD patients can directly increase calcification in vitro. In addition, in CKD, there are many mechanisms by which bone may adversely affect vascular calcification including disorders of bone remodelling, altered secretion of parathyroid hormone (PTH), hyperphosphatemia, hypercalcaemia, use of calcium based binders, and excessive vitamin D therapy. The coexistence of vascular risk factors and abnormal bone represent a double threat to the well being of patients with CKD.

New and improved glucocorticoid receptor ligands

The therapeutic and prophylactic use of glucocorticoids is widespread due to their powerful anti-inflammatory, antiproliferative and immunomodulatory activity. However, long-term use of these drugs can result in severe dose-limiting side effects. One of the most critical and debilitating side effects is osteoporosis, which leads to increased risk of fractures. Glucocorticoids damage bone through several different mechanisms. The search for novel glucocorticoids that have reduced side effects in bone and other tissues is being driven by the identification of new mechanisms of action of the glucocorticoid receptor. This may facilitate the detection of new, safer therapies with efficacies equivalent to currently prescribed steroids.

Recent advances in physiological calcium homeostasis

A constant extracellular Ca2+ concentration is required for numerous physiological functions at tissue and cellular levels. This suggests that minor changes in Ca2+ will be corrected by appropriate homeostatic systems. The system regulating Ca2+ homeostasis involves several organs and hormones. The former are mainly the kidneys, skeleton, intestine and the parathyroid glands. The latter comprise, amongst others, the parathyroid hormone, vitamin D and calcitonin. Progress has recently been made in the identification and characterisation of Ca2+ transport proteins CaT1 and ECaC and this has provided new insights into the molecular mechanisms of Ca2+ transport in cells. The G-protein coupled calcium-sensing receptor, responsible for the exquisite ability of the parathyroid gland to respond to small changes in serum Ca2+ concentration was discovered about a decade ago. Research has focussed on the molecular mechanisms determining the serum levels of 1,25(OH)2D3, and on the transcriptional activity of the vitamin D receptor. The aim of recent work has been to elucidate the mechanisms and the intracellular signalling pathways by which parathyroid hormone, vitamin D and calcitonin affect Ca2+ homeostasis. This article summarises recent advances in the understanding and the molecular basis of physiological Ca2+ homeostasis.

Factors other than glucocorticoids are involved in the osteoblast activity decrease caused by tissue injury

OBJECTIVE

Serum osteocalcin is a marker of bone formation. The concentration of osteocalcin is decreased with tissue injury. As glucocorticoids are known both to be increased in this situation and to diminish serum osteocalcin, we have hypothesized that they could be involved in this decrease.

DESIGN AND PATIENTS

We compared osteocalcin levels in two groups of patients undergoing abdominal surgery, one receiving thiopental, and the other etomidate, a glucocorticoid synthesis blocker. For comparative reasons, another protein decreased by glucocorticoids (osteoprotegerin) was measured in patients anaesthetized with thiopental.

MEASUREMENTS

Serum osteocalcin, cortisol and albumin were determined before and over the 24 h following surgery. Serum concentration of osteoprotegerin (OPG) and receptor activator of the nuclear factor kappaB ligand (RANKL) were also determined before and 24 h after surgery in a third group of nine patients who received thiopental for anaesthetic induction.

RESULTS

Cortisol levels were increased in the thiopental group, whereas, as expected, were decreased in etomidate patients. However, serum osteocalcin concentration decreased in a similar way in both groups. Serum OPG and RANKL levels were within the normal range at baseline and did not significantly change after surgery.

CONCLUSIONS

The decrease in serum osteocalcin induced by tissue injury is independent of the increase in cortisol secretion triggered by the latter. In addition, another pharmacologically proven effect of cortisol on bone metabolism, OPG inhibition, could not be demonstrated in the first 24 h following surgery, in spite of the physiological increase in endogenous cortisol secretion taking place in this period.

Osteoprotegerin as a potential therapy for osteoporosis

The discovery and characterization of the RANKL/RANK/OPG signaling pathway and the identification of its role in the pathogenesis of bone loss have provided the rationale for the development of drugs with the ability to modulate RANK-induced osteoclastogenesis. In vivo studies have identified interfering with the RANKL/RANK interaction as a potential therapeutic target in the management of osteoporosis. Two agents capable of blocking the binding of RANKL to RANK have been so far tested in clinical studies--osteoprotegerin (Fc-OPG fusion molecule) and the RANKL-antibody (AMG 162). Both have been found to have profound inhibitory effects on bone resorption, with AMG 162 appearing to be overall superior to OPG. Data are still very scarce, however, and much remains to be uncovered before novel strategies capable of modulating the RANKL/OPG signaling pathway could be safely and effectively used in the management of osteoporosis.

Osteoprotegerin as a potential therapy for osteoporosis

The discovery and characterization of the RANKL/RANK/OPG signaling pathway and the identification of its role in the pathogenesis of bone loss have provided the rationale for the development of drugs with the ability to modulate RANK-induced osteoclastogenesis. In vivo studies have identified interfering with the RANKL/RANK interaction as a potential therapeutic target in the management of osteoporosis. Two agents capable of blocking the binding of RANKL to RANK have been so far tested in clinical studies--osteoprotegerin (Fc-OPG fusion molecule) and the RANKL-antibody (AMG 162). Both have been found to have profound inhibitory effects on bone resorption, with AMG 162 appearing to be overall superior to OPG. Data are still very scarce, however, and much remains to be uncovered before novel strategies capable of modulating the RANKL/OPG signaling pathway could be safely and effectively used in the management of osteoporosis.

Osteoporosis due to Glucocorticoid Use in Children with Chronic Illness

Osteoporosis is increasingly recognized as a complication of chronic childhood illnesses, particularly when glucocorticoids (GCs) are necessary for treatment. Elucidation of the mechanisms leading to bone fragility in these settings requires disentanglement of the relative contributions of myriad risk factors, including disease activity, muscle weakness, immobilization, delayed growth and puberty, compromised nutrition, and osteotoxic medications. Over the years, bone mass and density evaluations by dual energy X-ray absorptiometry (DXA) have become popular for assessing bone health in children; however, such measurements are difficult to interpret because of the confounding effect of bone size and the lack of DXA-based densitometric criteria for defining osteoporosis in childhood. Recently, a new diagnostic approach for evaluation of densitometric data in children has been suggested, driven by Frost's mechanostat theory. A diagnostic algorithm based on the mechanostat theory of bone-muscle development is proposed for the characterization of bone disease in children with chronic illness. In addition to DXA-based assessments, techniques such as peripheral quantitative computerized tomography and ilial histomorphometry, for which there are pediatric reference data, are gaining ground in the characterization of skeletal changes due to chronic illness. Although these diagnostic techniques expand our understanding of osteoporosis in children, they do not replace clinical assessment. Concrete clinical evidence for GC-induced bone fragility can be seen in spinal changes due to vertebral compression, with spinal morphometry emerging as an essential, but frequently overlooked, tool in the evaluation of children's bone health. Presently, osteoporosis treatment in the chronic illness setting remains experimental and should be restricted to clinical studies. Following an understanding of the natural history of GC-induced osteoporosis in children, randomized, placebo-controlled prevention and intervention trials will be the next step toward the development of clinical practice guidelines.

Maternal plasma osteoprotegerin concentration in normal pregnancy

OBJECTIVE

Pregnancy is associated with major changes in calcium metabolism because the neonatal skeleton contains approximately 30 g of calcium, which are largely deposited in the third trimester. Osteoprotegerin (OPG) acts as a decoy receptor for the "Receptor Activator of Nuclear Factor-kappaB Ligand" (RANKL), which is an essential factor for bone remodeling. This study was conducted to determine whether there were changes in maternal plasma OPG concentration during normal pregnancy.

STUDY DESIGN

A cross-sectional study was performed in 433 patients of reproductive age (40 nonpregnant and 393 pregnant). Pregnant patients were classified into 4 groups according to gestational age: group 1: 11 to 14 weeks (n = 100); group 2: 15 to 18 weeks (n = 99); group 3: 27 to 30 weeks (n = 100); and group 4: 37 to 42 weeks (n = 94). Plasma OPG concentrations were measured with the use of a sensitive and specific immunoassay. Nonparametric statistics were used for analysis.

RESULTS

OPG was detected in the plasma of all women tested. The median OPG concentration was significantly higher in term patients than in those in early pregnancy (median: 6.63 pmol/L [range: 1.57-25.57] vs median: 3.98 pmol/L [range: 0.41-13.71], P < .001). There was no significant difference in plasma OPG concentrations between nonpregnant women and those in groups 1 or 2 (nonpregnant women median: 3.86 pmol/L [range: 1.64-15.29] vs group 1 median: 3.98 pmol/L [range: 0.41-13.71] vs group 2 median: 3.87 pmol/L [range: 1.14-69.83], P = .75).

CONCLUSION

The median maternal plasma OPG concentration is higher in the third trimester than in the first trimester of pregnancy. OPG may be involved in the regulation of bone turnover during pregnancy.

A bio-assay for effectors of osteoclast differentiation in serum from patients with bone disease

Osteoclast differentiation and activity, and hence bone loss, depend on two opposing cytokines. Receptor activator of NF-(kappa)B ligand (RANKL) produced by osteoblasts and T-cells stimulates, while osteoprotegerin inhibits. Both of these cytokines are found in serum. Our aim was to develop a functional assay for any factors present in human serum that can affect osteoclast differentiation and to assess whether any such factors vary in diseases in which bone loss occurs.

METHODS

Using a culture model of osteoclast differentiation in the presence of macrophage colony stimulating factor and soluble RANKL, we have measured the effects of different human sera on osteoclast differentiation. The production of a marker enzyme for the osteoclast, tartrate-resistant acid phosphatase (TRAP), was used to follow osteoclast differentiation.

RESULTS

In general, human serum stimulates osteoclast differentiation as indicated by TRAP activity, but in patients with low bone density this stimulation was attenuated. Sera from 40 female subjects with low bone mineral density showed significantly lower TRAP cell differentiation activity than sera from the healthy female controls.

CONCLUSION

We describe a functional bio-assay for factors in human serum which can affect osteoclast differentiation. This assay may have application in monitoring the effects of therapy in bone disease.

Modeling the interactions between osteoblast and osteoclast activities in bone remodeling

We propose a mathematical model explaining the interactions between osteoblasts and osteoclasts, two cell types specialized in the maintenance of the bone integrity. Bone is a dynamic, living tissue whose structure and shape continuously evolves during life. It has the ability to change architecture by removal of old bone and replacement with newly formed bone in a localized process called remodeling. The model described here is based on the idea that the relative proportions of immature and mature osteoblasts control the degree of osteoclastic activity. In addition, osteoclasts control osteoblasts differentially depending on their stage of differentiation. Despite the tremendous complexity of the bone regulatory system and its fragmentary understanding, we obtain surprisingly good correlations between the model simulations and the experimental observations extracted from the literature. The model results corroborate all behaviors of the bone remodeling system that we have simulated, including the tight coupling between osteoblasts and osteoclasts, the catabolic effect induced by continuous administration of PTH, the catabolic action of RANKL, as well as its reversal by soluble antagonist OPG. The model is also able to simulate metabolic bone diseases such as estrogen deficiency, vitamin D deficiency, senescence and glucocorticoid excess. Conversely, possible routes for therapeutic interventions are tested and evaluated. Our model confirms that anti-resorptive therapies are unable to partially restore bone loss, whereas bone formation therapies yield better results. The model enables us to determine and evaluate potential therapies based on their efficacy. In particular, the model predicts that combinations of anti-resorptive and anabolic therapies provide significant benefits compared with monotherapy, especially for certain type of skeletal disease. Finally, the model clearly indicates that increasing the size of the pool of preosteoblasts is an essential ingredient for the therapeutic manipulation of bone formation. This model was conceived as the first step in a bone turnover modeling platform. These initial modeling results are extremely encouraging and lead us to proceed with additional explorations into bone turnover and skeletal remodeling.

Changes in the serum growth factors and osteoprotegerin after bone marrow transplantation: impact on bone and mineral metabolism

The loss of bone mass often occurs after bone marrow transplantation (BMT), particularly during the early posttransplant period. There are few reports on the role of growth factors and osteoprotegerin (OPG) in the post-BMT bone loss. This study prospectively investigated 110 patients undergoing BMT and analyzed 36 patients who had dual-energy x-ray absorptiometry performed before BMT and 1 yr after BMT. The biochemical markers of bone formation and resorption were measured at the short-term intervals during the year-long follow-up. The serum IGF-I, IGF binding protein (IGFBP)-3, fibroblast growth factor-2, macrophage-colony stimulating factor (M-CSF), and OPG levels were measured before and 1 wk, 3 wk, and 3 months after BMT. The mean bone loss in the lumbar spine and the total proximal femur, which was calculated as the percent change from the baseline to the level at 1 yr, was 5.2% (P < 0.05) and 11.6% (P < 0.01), respectively. During the immediate post-BMT period, bone formation decreased, whereas bone resorption increased, which was indicated by the biochemical markers of bone turnover. The serum IGF-I levels also decreased progressively until 3 wk and then increased to the basal values at 3 months. The serum IGFBP-3 levels decreased progressively until 3 months. The serum fibroblast growth factor-2 levels decreased to the nadir at 1 wk and gradually recovered to the basal values at 3 months. The serum M-CSF levels increased immediately after BMT, which declined to its baseline level by 3 months. The serum OPG levels increased progressively, reached a peak at 3 weeks, and declined thereafter. There were significant correlations between the IGF-I and osteocalcin levels before BMT and at 3 wk after BMT (r = 0.45, P < 0.01; r = 0.54, P < 0.01). During the observation period, the serum IGFBP-3 and M-CSF levels showed positive correlations with the osteocalcin and serum collagen I carboxyl-terminal telopeptide levels, respectively. Although statistically not significant, the OPG levels tended to be positively associated with the serum collagen I carboxyl-terminal telopeptide levels. Significant correlations were observed between the percent changes from the baseline to 1 yr in the bone mineral density at the proximal femur and the serum IGF-I levels at 3 wk and 3 months after BMT (r = 0.52, P < 0.01; r = 0.41, P < 0.05).

Effect of systemic glucocorticoid therapy on bone metabolism and the osteoprotegerin system in patients with active Crohn's disease

BACKGROUND AND AIMS

Osteoporosis may occur in 25-30% of patients with Crohn's disease. Its pathogenesis is not completely understood. Both systemic inflammation in acute disease and treatment with systemic glucocorticoids have been implicated. The aim of the present study was to investigate changes in bone density and biochemical markers of bone metabolism before and during a 3-month period of high-dose glucocorticoid treatment for acute flare-up of Crohn's disease.

METHODS

Twenty-five patients with active Crohn's disease requiring systemic glucocorticoid treatment (prednisolone, 60 mg/day) were investigated. Lumbar spine and femoral neck bone mineral densitometry was performed at baseline and again after 3 months. Clinical examinations including evaluation of the Crohn's disease activity index and measurement of the biochemical markers osteocalcin, deoxypyridinoline, osteoprotegerin and the soluble receptor activator of NF-kappaB ligand were performed prior to, and at 1, 2 and 12 weeks following steroid administration. RESULTS Median lumbar bone mineral density decreased significantly during the observation period by 1.04% from -0.84 (t score; range, -2.8 to +0.57) to -0.95 (range, -3.1 to +0.40; P = 0.022), while bone density of the total femur decreased by 2.9% from -0.83 (range, -2.61 to +1.86) to -0.90 (range, -2.65 to +0.19; P = 0.01). Serum levels of osteocalcin, a bone formation marker, and osteoprotegerin, an anti-resorptive cytokine produced by osteoblasts, decreased after the first 2 weeks of treatment and reached baseline levels after 3 months. No significant change was found for the bone resorption marker deoxypyridinoline, while soluble receptor activator of NF-kappaB ligand, a cytokine promoting bone resorption, tended to increase during steroid treatment.

CONCLUSION

A decrease in bone mineral density in patients with Crohn's disease appears to result, at least in part, from a short-term effect of systemic glucocorticoid. Modulation of osteoclastogenesis by the receptor activator of NF-kappaB ligand/osteoprotegerin cytokine system and decreased osteoblastic function may be the underlying molecular basis.

Inhaled corticosteroids effects on bone in asthmatic and COPD patients: a quantitative systematic review

Deleterious effect of oral corticosteroids on bone has been well documented, whereas this remains debated for inhaled ones (ICS). Our objectives were to analyze the effects of ICS on bone mineral density, fracture risk and bone markers. We performed an exhaustive systematic research of all controlled trials potentially containing pertinent data, peer-reviewed by a dedicated WHO expert group, and comprehensive meta-analyses of the data. Inclusion criteria were ICS, and BMD/markers/fractures in asthma/chronic obstructive pulmonary diseases (COPD) and healthy patients. Analyses were performed in a conservative fashion using professional dedicated softwares and stratified by outcome, study design and ICS type. Results were expressed as standardized mean difference/effect size (ES), relative risk (RR) or odds ratio (OR), depending on study design and outcome units. Publication bias was investigated. Twenty-three trials were reviewed; 11 papers fit the inclusion criteria and were assessed for the main analysis. Quality scores for the randomized controlled trials (RCTs) were 80%, 71% for the prospective cohort studies, and 78% for the retrospective cohort and cross-sectional studies. We globally assessed ICS effects on BMD and found deleterious effects: ES=0.61 ( p=0.001) for healthy subjects, and ES=0.27 ( p<0.001) for asthma/COPD patients. For these patients, this effect was 0.21 ( p<0.01) at the lumbar spine, and 0.26 ( p<0.001) at the hip or femoral neck. A single study evaluated the impact of ICS on hip fracture and reported an increased OR of 1.6 (1.24; 2.03). Lumbar fracture rate differences did not reach the level of statistical significance: 1.87 (0.5; 6.94). Osteocalcin and PICP were decreased and ICTP, pyridinoline and deoxypyridinoline levels were not significantly affected. Budesonide (BUD) appeared to be the ICS inducing the less deleterious effects on bone, followed by beclomethasone dipropionate (BDP) and triamcinolone (TRI). Publication bias investigation provided non-significant results. In our meta-analyses, BUD at a mean daily dose (SD) of 686 microg (158 microg), BDP at 703 microg (123 microg) and TRI at 1,000 microg (282 microg) were found to affect bone mineral density and markers in patients suffering from the two major respiratory diseases. These findings could have practical implication in the long-term management of asthmatic and COPD patients.

A novel antiinflammatory maintains glucocorticoid efficacy with reduced side effects

Glucocorticoids (GCs) are commonly used to treat inflammatory disease; unfortunately, the long-term use of these steroids leads to a large number of debilitating side effects. The antiinflammatory effects of GCs are a result of GC receptor (GR)-mediated inhibition of expression of proinflammatory genes as well as GR-mediated activation of antiinflammatory genes. Similarly, side effects are most likely due to both activated and repressed GR target genes in affected tissues. An as yet unachieved pharmaceutical goal is the development of a compound capable of separating detrimental side effects from antiinflammatory activity. We describe the discovery and characterization of AL-438, a GR ligand that exhibits an altered gene regulation profile, able to repress and activate only a subset of the genes normally regulated by GCs. When tested in vivo, AL-438 retains full antiinflammatory efficacy and potency comparable to steroids but its negative effects on bone metabolism and glucose control are reduced at equivalently antiinflammatory doses. The mechanism underlying this selective in vitro and in vivo activity may be the result of differential cofactor recruitment in response to ligand. AL-438 reduces the interaction between GR and peroxisomal proliferator-activated receptor gamma coactivator-1, a cofactor critical for steroid-mediated glucose up-regulation, while maintaining normal interactions with GR-interacting protein 1. This compound serves as a prototype for a unique, nonsteroidal alternative to conventional GCs in treating inflammatory disease.

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.

Hypercalcemia in Langerhans cell histiocytosis: is it therapy-related?

Hypercalcemia is not known to be a common occurrence in patients with Langerhans cell histiocytosis (LCH). This manuscript describes an infant with multisystem LCH who developed an elevated serum calcium level while on therapy. Unlike other cases of hypercalcemia, this patient did not have evidence of bone involvement. Based on the apparent rarity of the condition and the clinical presentation, it is likely that hypercalcemia in LCH is a multifactorial process. The author presents evidence supporting the hypothesis that the treatment regimen is a major factor in the etiology of this metabolic abnormality and suggests that calcium levels be routinely measured during therapy.

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.