Emerging consensus on prevention and treatment of glucocorticoid-induced osteoporosis

Prednisolone induces osteocytes apoptosis by promoting Notum expression and inhibiting PI3K/AKT/GSK3β/β-catenin pathway

The apoptosis of mature osteocytes is the main factor causing damage to the microstructure of cortical bone in glucocorticoid-induced osteoporosis (GIOP). Our previous research found damaged areas and empty osteocytes lacunae in the tibial cortical bone of GIOP mice. However, the specific mechanism has not been clarified. Recently, a study showed that the quality of the cortical bone significantly increased by knocking out Notum, a gene encoding α/β hydrolase. However, it is not clear whether Notum affects cortical bone remodeling by participating in glucocorticoids (GCs)-induced apoptosis of osteocytes. The present study aimed to explore the correlation between Notum, osteocytes apoptosis, and cortical bone quality in GIOP. Prednisolone acetate was intragastrically administered to mice for two weeks. Histochemical staining was applied to evaluate changes in GIOP and Notum expression. Osteocytes were stimulated with prednisolone, and cell viability was assessed via CCK8. Hoechst 33342/PI staining, flow cytometry, RT-PCR, and western blot were used to detect osteocytes apoptosis, siRNA transfection efficiency, and expressions of pathway related factors. The results showed that the number of empty osteocytes lacunae increased in GIOP mice. TUNEL-stained apoptotic osteocytes and Notum immuno-positive osteocytes were also observed. Furthermore, prednisolone was found to promote Notum expression and osteocytes apoptosis in vitro. Knocking down Notum via siRNA partially restored osteocytes apoptosis and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase-3β (GSK3β)/β-catenin pathway. These findings showed GCs-induced osteocytes apoptosis by promoting Notum expression and inhibiting PI3K/AKT/GSK3β/β-catenin pathway. Thus, Notum might be a potential therapeutic target for the treatment of GIOP.

Technetium-99 Conjugated with Methylene Diphosphonate Ameliorates Glucocorticoid Induced Osteoporosis by Inhibiting Osteoclastogenesis

Technetium-99 conjugated with methylene diphosphonate (⁹⁹Tc-MDP) is an effective anti-inflammatory drug in treating rheumatoid arthritis (RA) for over 15 years in China. However, as a special form of bisphosphonate, the antiosteoporotic effect of ⁹⁹Tc-MDP is unclear. We systematically investigated the effects of ⁹⁹Tc-MDP on cancellous and cortical bone, respectively, in glucocorticoid induced osteoporosis (GIO) animal models. Forty-eight Sprague-Dawley rats were randomly divided into six groups: blank, negative control, high dose, medium dose, low dose, and positive control groups. After dexamethasone was given to all groups except the blank group to induce osteoporosis, the rats in different groups were treated with saline, MDP, or different doses of ⁹⁹Tc-MDP. After treatment, all rats were sacrificed, and their tibiae and femora were analyzed with microcomputed tomography (micro-CT), histology and biomechanics. Micro-CT analyses showed that (1) ⁹⁹Tc-MDP reversed glucocorticoid induced bone microarchitecture destruction by increasing BV/TV, Tb.Th, and Tb.N and decreasing BS/BV, Tb.Sp, and TBPf; (2) effect of ⁹⁹Tc-MDP increased as its dosage increased; and (3) ⁹⁹Tc-MDP could improve cortical bone thickness while MDP failed to do so. Micro-CT spatial structure analysis and histology also yielded consistent results, indicating that ⁹⁹Tc-MDP increased trabecular number and connectivity morphologically. Secondly, biomechanics revealed that ⁹⁹Tc-MDP can enhance the extrinsic stiffness of bone by changing bone geometry. Finally, ⁹⁹Tc-MDP could inhibit osteoclastogenesis in PBMCs in human. In conclusion, ⁹⁹Tc-MDP exerted antiosteoporotic effect by improving both cancellous and cortical bone, as well as increasing extrinsic bone stiffness which might be attributed to the its inhibition of osteoclast differentiation. The antiosteoporotic effect of ⁹⁹Tc-MDP may suggest a potential clinical application for patients with GIO.

Autophagy as a target for glucocorticoid-induced osteoporosis therapy

Autophagy takes part in regulating the eukaryotic cells function and the progression of numerous diseases, but its clinical utility has not been fully developed yet. Recently, mounting evidences highlight an important correlation between autophagy and bone homeostasis, mediated by osteoclasts, osteocytes, bone marrow mesenchymal stem cells, and osteoblasts, and autophagy plays a vital role in the pathogenesis of glucocorticoid-induced osteoporosis (GIOP). The combinations of autophagy activators/inhibitors with anti-GIOP first-line drugs or some new autophagy-based manipulators, such as regulation of B cell lymphoma 2 family proteins and caspase-dependent clearance of autophagy-related gene proteins, are likely to be the promising approaches for GIOP clinical treatments. In view of the important role of autophagy in the pathogenesis of GIOP, here we review the potential mechanisms about the impacts of autophagy in GIOP and its association with GIOP therapy.

Characteristics and diagnostic workup of the patient at risk to sustain fragility fracture

The human body undergoes several physiological adaptations as a result of the aging process. Amongst other organs, the skeleton is also affected and when bone fragility is present, an increase in both morbidity and mortality has been reported. Identification of risk factors to calculate the probability for a given patient to develop a fragility fracture it is therefore of paramount importance. Moreover, the existence of an in house protocol for diagnostic work up using biochemical tests and imaging investigations is essential. In the herein study we discuss a diagnostic protocol that has been developed in our clinic based on knowledge from the literature and our clinical experience.

Glucocorticoid-induced osteoporosis: who to treat with what agent?

Among the adverse events of glucocorticoid treatment are bone loss and fractures. Despite available, effective preventive measures, many patients receiving or initiating glucocorticoid therapy are not appropriately evaluated and treated for bone health and fracture risk. Populations with, or at risk of, glucocorticoid-induced osteoporosis (GIOP) to target for these measures are defined on the basis of dose and duration of glucocorticoid therapy and bone mineral density. That patients with GIOP should be treated as early as possible is generally agreed upon; however, diversity remains in intervention thresholds and management guidelines. The FRAX(®) algorithm provides a 10-year probability of fracture that can be adjusted according to glucocorticoid dose. There is no evidence that GIOP and postmenopausal osteoporosis respond differently to treatments. Available anti-osteoporotic therapies such as anti-resorptives including bisphosphonates and the bone anabolic agent teriparatide are effective for the management of GIOP. Prevention with calcium and vitamin D supplementation is less effective than specific anti-osteoporotic treatment. Anti-osteoporotic treatment should be stopped at the time of glucocorticoid cessation, unless the patient remains at increased risk of fracture.

Are glucocorticoid-induced osteoporosis recommendations sufficient to determine antiosteoporotic treatment for patients with rheumatoid arthritis?

BACKGROUND/AIMS

We investigated differences in identifying candidates for antiosteoporotic treatment in rheumatoid arthritis (RA) patients according to two available clinical guidelines.

METHODS

We prospectively enrolled 100 female patients aged 50 years or older with RA who visited Hanyang University Hospital for periodic examinations between April 2011 and August 2011. We applied the glucocorticoid-induced osteoporosis (GIOP) recommendations and the National Osteoporosis Foundation (NOF) guidelines to RA patients and examined agreement between the guidelines for identifying candidates for antiosteoporotic treatment. We also analyzed the impact of screening vertebral fractures (VFs) in determining the treatment of osteoporosis in RA patients.

RESULTS

The 57 patients taking glucocorticoids were classified into high-risk (n = 23), medium-risk (n = 16), and low-risk (n = 18) groups according to the GIOP recommendations. Based on the NOF guidelines, 36 of 57 patients were candidates for antiosteoporotic treatment and the agreement between two guidelines was high (κ = 0.76). Two of the 18 patients in the low-risk group and 19 of 43 patients not eligible per the GIOP recommendations were classified as candidates for antiosteoporotic treatment by the NOF guidelines.

CONCLUSIONS

In determining antiosteoporotic treatment for RA patients, using only the GIOP recommendations is insufficient. Application of the NOF guidelines in patients not eligible for or classified into the low-risk group per the GIOP recommendations and screening for VFs may be helpful in deciding on antiosteoporotic treatment in RA patients.

A review of the use of dual-energy X-ray absorptiometry (DXA) in rheumatology

The principal use of dual-energy X-ray absorptiometry (DXA) is to diagnose and monitor osteoporosis and therefore reduce fracture risk, associated morbidity, and mortality. In the field of rheumatology, DXA is an essential component of patient care because of both rheumatologists’ prescription of glucocorticoid treatment as well as the effects of rheumatological diseases on bone health. This review will summarize the use of DXA in the field of rheumatology, including the concern for glucocorticoid-induced osteoporosis, as well as the association of osteoporosis with a sampling of such rheumatologic conditions as rheumatoid arthritis (RA), systemic lupus erythematosus, ankylosing spondylitis, juvenile idiopathic arthritis, and scleroderma or systemic sclerosis. Medicare guidelines recognize the need to perform DXA studies in patients treated with glucocorticoids, and the World Health Organization FRAX tool uses data from DXA as well as the independent risk factors of RA and glucocorticoid use to predict fracture risk. However, patient access to DXA measurement in the US is in jeopardy as a result of reimbursement restrictions. DXA technology can simultaneously be used to discover vertebral fractures with vertebral fracture assessment and provide patients with a rapid, convenient, and low-radiation opportunity to clarify future fracture and comorbidity risks. An emerging use of DXA technology is the analysis of body composition of RA patients and thus the recognition of “rheumatoid cachexia,” in which patients are noted to have a worse prognosis even when the RA appears well controlled. Therefore, the use of DXA in rheumatology is an important tool for detecting osteoporosis, reducing fracture risk and unfavorable outcomes in rheumatological conditions. The widespread use of glucocorticoids and the underlying inflammatory conditions create a need for assessment with DXA. There are complications of conditions found in rheumatology that could be prevented with more widespread patient access to DXA.

Management of glucocorticoid-induced osteoporosis

This review summarizes the available evidence-based data that form the basis for therapeutic intervention and covers the current status of glucocorticoid-induced osteoporosis (GIOP) management, regulatory requirements, and risk-assessment options. Glucocorticoids are known to cause bone loss and fractures, yet many patients receiving or initiating glucocorticoid therapy are not appropriately evaluated and treated. An European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis workshop was convened to discuss GIOP management and to provide a report by a panel of experts. An expert panel reviewed the available studies that discussed approved therapeutic agents, focusing on randomized and controlled clinical trials reporting on bone mineral density and/or fracture risk of at least 48 weeks' duration. There is no evidence that GIOP and postmenopausal osteoporosis respond differently to treatments. The FRAX algorithm can be adjusted according to glucocorticoid dose. Available antiosteoporotic therapies such as bisphosphonates and teriparatide are efficacious in GIOP management. Several other agents approved for the treatment of postmenopausal osteoporosis may become available for GIOP. It is advised to stop antiosteoporotic treatment after glucocorticoid cessation, unless the patient remains at increased risk of fracture. Calcium and vitamin D supplementation as an osteoporosis-prevention measure is less effective than specific antiosteoporotic treatment. Fracture end-point studies and additional studies investigating specific subpopulations (pediatric, premenopausal, or elderly patients) would strengthen the evidence base and facilitate the development of intervention thresholds and treatment guidelines.

Treatment of glucocorticoid-induced osteoporsis

Glucocorticoid-induced osteoporosis (GIO) is the most common form of secondary osteoporosis. Fractures occur in 30-50% of patients with GIO. Therefore, treatment of this disease is critical. Although patients should receive supplemental calcium and vitamin D, additional measures are necessary to prevent fractures. Estrogens and androgens may be of value in patients with hypogonadism, but bisphosphonates and teriparatide are the most effective agents in the treatment of GIO. Bisphosphonates prevent the early bone loss that follows exposure to glucocorticoids, and which has been attributed to increased resorption. Teriparatide appears to be more effective than alendronate in established GIO when reduced bone formation is the predominant pathophysiological mechanism. In conclusion, GIO can be prevented and treated with appropriate medical intervention.

Avaliação da prevalência de osteoporose e fraturas vertebrais em pacientes portadores de doença pulmonar obstrutiva crônica

INTRODUÇÃO: A osteoporose é uma doença progressiva que contribui para o surgimento de fraturas vertebrais. OBJETIVOS: Avaliar a prevalência da osteoporose, fraturas vertebrais e intensidade da dor nas regiões da coluna vertebral em pacientes com DPOC moderada e grave, além de verificar se há relação entre tais variáveis e a gravidade da obstrução pulmonar. MATERIAIS E MÉTODOS: Foram avaliados 34 indivíduos portadores de DPOC (GDPOC) e 33 indivíduos saudáveis (GC), por meio da densitometria óssea e radiografias da coluna torácica e lombar. RESULTADOS: Não houve diferenças significativas intergrupos nos dados antropométricos. O GDPOC apresentou valores menores nas variáveis espirométricas, na densidade mineral óssea (DMO) e no escore-T, quando comparado com o GC (p < 0,05; Teste t Student); além disso, não se observou correlação entre VEF1 e DMO e escore-T (Correlação de Pearson, p > 0,05). Verificou-se uma alta prevalência de osteoporose, sendo que 20 indivíduos (59%) com obstrução moderada apresentaram na coluna lombar, l (3%) no colo do fêmur e l (3%) no trocânter; 4 (12%) com obstrução pulmonar grave na coluna lombar, l (3%) no colo do fêmur e l (3%) no trocânter. Vinte indivíduos (59%) do GDPOC com osteoporose apresentaram fraturas de graus I e II, 4 (12%) grau III (k = 0,90; IC: 95%) e 3 indivíduos do GDPOC relataram presença de dor com intensidade "leve" na região toracolombar, enquanto 21 apresentaram fraturas vertebrais osteoporóticas assintomáticas. CONCLUSÃO Concluímos que os indivíduos com DPOC de moderada a grave apresentaram, além do comprometimento pulmonar, diminuição da DMO e fraturas vertebrais osteoporóticas, o que indica a necessidade de se adotar medidas de prevenção da osteoporose nesses pacientes.

A reappraisal of generic bisphosphonates in osteoporosis

The competitive price of generic bisphosphonates has had a marked effect on practice guidelines, but an increasing body of evidence suggests that they have more limited effectiveness than generally assumed.

INTRODUCTION

The purpose of this study is to review the impact of generic bisphosphonates on effectiveness in the treatment of osteoporosis.

METHODS

This study is a literature review.

RESULTS

A substantial body of evidence indicates that many generic formulations of alendronate are more poorly tolerated than the proprietary preparations which results in significantly poorer adherence and thus effectiveness. Poorer effectiveness may result from faster disintegration times of many generics that increase the likelihood of adherence of particulate matter to the oesophageal mucosa. Unfortunately, market authorisation, based on the bioequivalence of generics with a proprietary formulation, does not take into account the potential concerns about safety. The poor adherence of many generic products has implications for guideline development, cost-effectiveness and impact of treatment on the burden of disease.

CONCLUSIONS

The impact of generic bisphosphonates requires formal testing to re-evaluate their role in the management of osteoporosis.

Clinical question: What is the best approach to managing glucocorticoid-induced osteoporosis?

Glucocorticoid-induced osteoporosis is common, and the resulting fractures cause significant morbidity and mortality. Rapid bone loss and increased fracture risk occur soon after the initiation of glucocorticoid therapy and are dose dependent. The increase in fracture risk is partly independent of bone mineral density, probably as a result of changes in bone material properties and increased risk of falling. Fracture risk can be assessed using the FRAX algorithm, although risk may be underestimated in patients taking higher doses of glucocorticoids. Because of the rapidity of bone loss and increase in fracture risk after the start of glucocorticoid therapy, primary prevention should be advised in high-risk individuals, for example older women and men, individuals with a previous fracture history and those with low bone mineral density. Bisphosphonates are the front-line choice for the prevention of fracture in the majority of glucocorticoid-treated patients, with teriparatide as a second-line option. Calcium and vitamin D supplements should be co-prescribed unless there is evidence of an adequate dietary calcium intake and vitamin D status.

An observational study of glucocorticoid-induced osteoporosis prophylaxis in a national cohort of male veterans with rheumatoid arthritis

We applied regression techniques to a large cohort of patients to understand why certain patients are prescribed medications to prevent glucocorticoid-induced osteoporosis (GIO). Rates of prescriptions to prevent osteoporosis were low. The presence of drugs and disorders associated with osteoporosis and gastrointestinal conditions actually are associated with a decreased likelihood of receiving osteoporosis-preventing medications.

INTRODUCTION

To understand why some patients are prescribed medications to prevent GIO while other patients are not, we examined whether there is an association among osteoporosis-inducing medical conditions or medications and prescriptions for osteoporosis prophylaxis in a large cohort of rheumatoid arthritis patients on chronic glucocorticoids.

METHODS

Department of Veterans' Affairs national administrative databases were used to construct a cohort (n = 9,605) and provide the data for this study. Multivariate logistic regression was performed to determine medical conditions and medications associated with dispensing of GIO-preventive medications, controlling for sociodemographic variables, comorbidities, glucocorticoid dosage, prior fractures, and rheumatoid arthritis severity. A subanalysis examined predictors of early GIO prevention.

RESULTS

Subjects were more likely to receive GIO prophylaxis if they were older, African American, treated with multiple antirheumatic disease-modifying drugs, or received greater glucocorticoid exposure. The prescription of certain drug classes (loop diuretics and anticonvulsants) and conditions (malignancy, renal insufficiency, alcohol abuse, and hepatic disease) were associated with lower likelihood of GIO prophylaxis, despite putative links between these agents/conditions and osteoporosis. The presence of gastrointestinal disorders dramatically decreased likelihood of GIO prophylaxis. Few characteristics predicted the dispensing of GIO-preventing medications within 7 days of the initial glucocorticoid start date.

CONCLUSIONS

Rates of prescriptions to prevent osteoporosis in a cohort of older men with rheumatoid arthritis on chronic glucocorticoids were low. Gastrointestinal disorders and drugs and disorders potentially linked to osteoporosis are associated with diminished odds of being prescribed GIO-preventing medications.

Efficacy and safety of zoledronic acid in the treatment of glucocorticoid-induced osteoporosis

Glucocorticoids are essential in treating many disorders and they are widely used in spite of their negative impact on the skeletal system. As bisphosphonates reduce bone resorption through their action on osteoclasts, they play an important role in management of glucocorticoid-induced osteoporosis. Unlike other bisphosphonates, zoledronic acid is given by intravenous infusion and it has a potential advantage of increasing the compliance and adherence of patients when it is given 5 mg once a year. However, this treatment modality seems to be associated with more adverse events than oral administrations, and further studies with longer follow-up periods must be conducted to determine the safety and cost-effectiveness of long-term treatment with zoledronic acid.

Osteoporosis-related simultaneous four joints fractures and dislocation after a seizure: a case report

A case of steroid-induced osteoporosis-related multiple fractures and dislocations are described after a seizure is reported. Patient had two years history of steroid use with no supplement or antiresorptive therapy. There was a delay in the diagnosis which affected an otherwise good outcome in such situations. It is recommended that patients on steroid should be given calcium, vitamin D, and an antiresorptive. Furthermore, a meticulous clinical examination is required in patients who are on steroids and suffer epileptic seizures to rule out skeletal injury.

Glucocorticoids and the risk of osteoporosis

BACKGROUND

Glucocorticoid-induced osteoporosis (GIO) refers to a clinical condition in which a class of corticosteroids increases the susceptibility of bones to fracture. Numerous recent studies have improved our understanding of the underlying biology of this condition, whereas data from randomized controlled trials have provided clinicians with more options for prevention of GIO.

OBJECTIVE

To review the pathophysiology and epidemiology of GIO, as well as current pharmacologic treatment and prevention modalities available. To review the state of healthcare provider concordance with GIO prevention guidelines.

METHODS

Representative examples of various cellular and molecular processes underlying GIO were included, with an emphasis towards more recent discoveries. The data used to describe the epidemiology of GIO were derived from both randomized controlled studies and observational studies, framed through a discussion of known osteoporosis risk factors.

RESULTS/CONCLUSION

Progress has been made in clarifying the pathophysiologic mechanisms that result in GIO. Although the options for preventions and treatment of GIO continue to expand, provider compliance with preventive measures remains suboptimal.

Weekly clodronate treatment prevents bone loss and vertebral fractures in women with subclinical Cushing's syndrome

INTRODUCTION

Chronic mild endogenous glucocorticoid excess has been shown to cause bone loss and to increase fracture risk in both post-menopausal and premenopausal women. Currently, it is unclear if patients with subclinical Cushing's syndrome (SCS) with osteoporosis or osteopenia may benefit from antiresorptive treatment and the type of therapy to be given.

OBJECTIVE

This pilot randomized study was aimed at evaluating the effects of 12-month im administration of clodronate (100 mg every week) on vertebral and femoral bone mineral density (BMD), bone turnover markers and on subjective pain in premenopausal women with SCS due to adrenal incidentalomas.

METHODS

Forty-six women (age, 43.1+/-7.7 yr) with SCS due to adrenal incidentaloma and osteoporosis/osteopenia were randomized to receive clodronate plus supplement of Calcium (500 mg daily) and Vitamin D3 (800 mg daily) (group 1, no.=23) or supplements only (group 2, no.=23). Both groups were similar in terms of age, body mass index, cortisol levels, BMD values, and bone turnover markers. All of the women were re-evaluated after 12 months.

RESULTS

After 12 months of treatment, in group 1, a significant increase in lumbar BMD occurred (p=0.04), while bone turnover markers decreased by about one third (p<0.05). In group 2, bone turnover markers did not change and BMD values slightly decreased (p=ns). The differences in bone turnover markers and in lumbar BMD between the two groups were significant (p<0.05, all). No new vertebral fracture occurred in group 1, while in group 2 the spine radiographies revealed 2 new fractures and a worsening of two pre-existent fractures. An improvement in subjective back pain, assessed by visual analogue scale pain score was observed in group 1 (from 4.3+/-2.7 to 2.9+/-2.0; p<0.05) but not in group 2 (from 4.4+/-3.1 to 4.2+/-3.4; p=ns). No significant changes occurred in cortisol secretion or clinical picture of the SCS during the study.

CONCLUSIONS

Intramuscular administration of clodronate effectively increased lumbar BMD values, preserved bone mass at the femoral neck, stabilized vertebral fracture index, and decreased subjective back pain in pre-menopausal women with SCS. Since the untreated group continued to lose bone, antiresorptive treatment should be considered in patients with SCS, according to the prevision of surgical treatment, prevalent fractures, BMD values, age, concomitant morbidities, and desire for pregnancy.

Strategies for minimizing corticosteroid toxicity: a review

Glucocorticoids (GCs) are used commonly for the treatment of various pediatric inflammatory and autoimmune diseases. Although potent and generally effective, they are not without risks for producing serious adverse effects, especially when used in high doses for prolonged periods of time. For proper use of systemic glucocortcoids, a basic knowledge of the pharmacology, clinical usage guidelines, and adverse reactions of these agents is imperative. This review article emphasis on the commonly observed side-effects encountered with GC use in children and their underlying basic pathophysiological mechanisms. The appropriate anticipation of these side-effects with timely implementation of the suggested evidencebased guidelines has the potential significantly to prevent, minimize and treat common and disabling complications of glucocortcoid therapy.

Vitamin D and glucocorticoids differentially modulate chemokine expression in human airway smooth muscle cells

BACKGROUND AND PURPOSE

Chemokines play a critical role in the pathogenesis of asthma and facilitate the recruitment of inflammatory cells in the airways. Evidence now suggests that airway smooth muscle (ASM) may serve as a source of chemokines in inflamed airways. Although vitamin D has potent anti-inflammatory properties in vitro in some cell types, its effects on ASM cells remain unclear. Here, we investigated whether 1alpha, 25-dihydroxy vitamin D3 (calcitriol) modulated chemokine production in ASM.

EXPERIMENTAL APPROACH

Human ASM cell cultures were derived from tracheal samples taken during surgery. ASM cells were treated with tumour necrosis factor alpha (TNFalpha) and/or interferon gamma (IFNgamma) for 24 h in the presence of calcitriol and/or the glucocorticoid fluticasone added 2 h before. RANTES (regulated upon activation, normal T-cell expressed and secreted), interferon-inducible protein 10 (IP-10) and fractalkine (FKN) levels in cell supernatants were measured by ELISA.

KEY RESULTS

In TNFalpha-treated cells, calcitriol inhibited RANTES and IP-10 secretion in a concentration-dependent manner. FKN levels were negligible. In TNFalpha/IFNgamma-treated cells, whereas fluticasone or calcitriol alone partially inhibited RANTES secretion (by 38 and 20%, respectively), the combination of both drugs additively inhibited RANTES secretion (by 60%). No effect was observed on IP-10 secretion. Whereas fluticasone enhanced FKN secretion (by 50%), calcitriol significantly decreased FKN levels (by 50%). Interestingly, calcitriol blocked the stimulatory effect of fluticasone on FKN secretion, which was inhibited by 60% with the combination of calcitriol and fluticasone.

CONCLUSIONS AND IMPLICATIONS

These findings suggest that vitamin D uniquely modulates human ASM expression of chemokines and may exert some beneficial effects in the treatment of steroid-resistant patients with asthma.

Glucocorticoid-Induced osteoporosis: clinical and therapeutic aspects

Glucocorticoid-induced osteoporosis (GIO) is the most common form of secondary osteoporosis. Fractures, which are often asymptomatic, may occur in as many as 30_50% of patients receiving chronic glucocorticoid therapy. Vertebral fractures occur early after exposure to glucocorticoids, at a time when bone mineral density (BMD) declines rapidly. Fractures tend to occur at higher BMD levels than in women with postmenopausal osteoporosis. Glucocorticoids have direct and indirect effects on the skeleton. They impair the replication, differentiation, and function of osteoblasts and induce the apoptosis of mature osteoblasts and osteocytes. These effects lead to a suppression of bone formation, a central feature in the pathogenesis of GIO. Glucocorticoids also favor osteoclastogenesis and as a consequence increase bone resorption. Bisphosphonates are the most effective of the various therapies that have been assessed for the management of GIO. Anabolic therapeutic strategies are under investigation. Teriparatide seems to be also efficacious for the treatment of patients with GIO.