High-dose glucocorticoids in multiple sclerosis patients exert direct effects on the kidney and skeleton

Glucocorticoid-induced osteoporosis: pathophysiological data and recent treatments

Long-term glucocorticoid therapy promptly induces osteoporosis, whose severity depends on the dose and duration of the treatment. Recent data suggest that there is no safety threshold for adverse effects on bone. Glucocorticoid therapy impairs calcium intestinal absorption, dramatically suppresses osteoblastic formation, and stimulates osteocyte apoptosis. In contrast, the contribution of secondary hyperparathyroidism and increased bone resorption, although frequently mentioned, is now a focus of controversy. Beneficial effects on bone have been obtained with calcium and vitamin D supplementation, as well as with hormone replacement therapy (HRT) in postmenopausal women. Bisphosphonates are clearly effective in preventing and treating glucocorticoid-induced osteoporosis, although their mechanism of action in this condition remains poorly understood. Parathyroid hormone (PTH) is being evaluated as a potential therapeutic agent for glucocorticoid-induced osteoporosis.

Dexamethasone enhances vitamin D-24-hydroxylase expression in osteoblastic (UMR-106) and renal (LLC-PK1) cells treated with 1alpha,25-dihydroxyvitamin D3

Chronic glucocorticoid therapy causes rapid bone loss and clinical osteoporosis. We previously found that dexamethasone, a potent glucocorticoid, increased renal expression of vitamin D-24-hydroxylase, which degrades such vitamin D metabolites as 25-hydroxyvitamin D3 and 1alpha,25-dihydroxyvitamin D3 (1,25[OH]2D3). We therefore investigated the mechanisms of this increase in UMR-106 osteoblast-like cells and LLC-PK1 kidney cells. To induce 24-hydroxylase expression, 1,25(OH)2D3 (10(-7)M) and dexamethasone were added simultaneously to the medium of LLC-PK1 cells, and 24 h before dexamethasone treatment, 1,25(OH)2D3 was added to the medium of UMR-106 cells. Dexamethasone dose dependently increased 24-hydroxylase mRNA and enzymatic activity in 1,25(OH)2D3-treated LLC-PK1 and UMR-106 cells. Maximal stimulation was observed with 10(-6) M dexamethasone in both cell lines. The addition of 10(-6) M dexamethasone significantly increased the abundance of 24-hydroxylase mRNA by 24 and 8 h in 1,25(OH)2D3-treated LLC-PK1 and UMR-106 cells, respectively. Stimulation for dexamethasone in UMR-106 cells persisted for up to 48 h. Dexamethasone stimulation of 24-hydroxylase mRNA expression in UMR-106 cells was abolished by pretreatment with cycloheximide, an inhibitor of protein synthesis. Northern and Western analyses indicated that 10(-6) M dexamethasone markedly increased the abundance of c-fos mRNA at 20 min and c-fos protein concentration at 60 min in 1,25(OH)2D3-treated UMR-106 cells but only slightly induced the abundance of c-jun mRNA. The addition of phorbol 12-myristate 13-acetate increased mRNA expression for both c-fos and 24-hydroxylase in 1,25(OH)2D3-treated UMR-106 cells. The effect of dexamethasone on 24-hydroxylase mRNA expression was blocked by RO31-8220, a specific inhibitor of protein kinase C. Thus, dexamethasone in the presence of 1,25(OH)2D3 enhances expression of 24-hydroxylase in UMR-106 osteoblastic cells via new protein synthesis. The mechanism of this effect appears to involve activation of the AP-1 site by increased c-fos protein.

Effects of high doses of corticosteroids on bone metabolism

The effects of a chronic treatment with corticosteroids on bone are well known, but few data are available regarding the acute effect of these drugs on bone turnover. This study was aimed at evaluating the effects of high doses of corticosteroids administered for a short period on bone metabolism. We assessed 23 subjects (15 women and 8 men) suffering from multiple sclerosis and treated with methylprednisolone (1 g i.v. for 10 days) followed by oral prednisone for 9 days; patients affected by diseases involving bone or treated during the previous 6 months with drugs influencing bone metabolism were excluded. We observed a significant decrease of ALP and bone glia protein (BGP), in these subjects, and a significant sudden increase of urinary calcium/creatinine and urinary cross-laps after 3 days of treatment. All of these parameters, except urinary calcium/creatinine, returned to basal levels after 30 days from the beginning of treatment (11 days after the interruption of corticosteroids administration). Serum phosphorus showed a significant decrease after 3 days of treatment, but returned to basal levels after 10 days. These data suggest that high doses of corticosteroids administered for a short period are able to induce an increase of bone resorption and a decrease of bone formation; moreover, bone turnover returns to basal levels when the treatment is stopped.

The pharmacological management of drug-induced rheumatic disorders

Many drugs can induce adverse effects such as rheumatoid disorders, which we need to be aware of in order to best detect and manage them. New drugs are constantly entering the marketplace and can cause an increasing number of disorders. Through this article, we review the prevention and pharmacological management of drug-induced rheumatic disorders. These include articular and peri-articular manifestations induced by fluoroquinolones, retinoids, cyclosporin, drug-induced disorders of bone metabolism such as corticosteroid-induced osteoporosis and drug-induced osteomalacia, and multisystemic manifestations including drug-induced lupus and arthritis induced by vaccinations and cytokines.

Spine abnormalities and damage in patients cured from Cushing's disease

The skeletal system is a common target of glucocorticoids. Structural and functional impairment of skeletal system is a relevant cause of morbidity and disability in patients with Cushing's syndrome. Thirty-six patients long-term (3.9 +/- 0.5 yrs) cured from Cushing's disease (CD), 26 with adulthood-onset CD (AOCD) and 10 with childhood-onset CD (COCD) and 2 groups of controls, 24 age- and sex-matched patients with nonfunctioning pituitary adenomas (NFA) and 36 age- and sex-matched healthy subjects (HS), entered this open transversal controlled study to evaluate the prevalence of spine abnormalities and damage by standard radiography in subjects with a history of Cushing's syndrome. Symptoms and signs of backache were present in 86.1% CD patients (100% COCD and 80.8% AOCD), in 30.5% HS (chi2 = 20.6, p < 0.0001) and 37.5% NFA patients (chi2 = 13.2, p < 0.0001). The prevalence of trabecular bone rarefaction (chi2 = 6.5, p < 0.01 and chi2 = 4.5, p < 0.05), vertebral collapse (chi2 = 10.7, p < 0.01 and chi2 = 7.0, p < 0.01) and scoliosis (chi2 = 10.9, p < 0.01 and chi2 = 11.1, p < 0.01) resulted significantly increased in CD patients as compared both to HS and NFA patients. In CD patients, the number of collapsed vertebral bodies was significantly correlated to age of disease onset (r = -0.63, p < 0.0001), disease duration (r = 0.33, p < 0.05) and urinary free cortisol levels at disease diagnosis (r = 0.72, p < 0.0001). The prevalence of cortical bone sclerosis was significantly increased in AOCD than in HS (chi2 = 6.5, p < 0.01) and COCD (chi2 = 7.7, p < 0.01) whereas that of trabecular bone rarefaction was significantly higher in COCD patients than in HS (chi2 = 18.3, p < 0.0001), NFA (chi2 = 14.2, p < 0.0001) and AOCD patients (chi2 = 9.1, p < 0.01). Patients cured from CD have increased prevalence of spine damage, mostly when the disease developed before the completion of skeletal growth. Therefore, a periodical radiological follow-up of the skeleton and a specific treatment for the bone damage should be included in the management of patients with Cushing's syndrome.

Corticosteroid osteoporosis

Corticosteroids are widely used and effective agents for the control of many inflammatory diseases, but corticosteroid osteoporosis is a common problem associated with their long term high dose use. Prevention of corticosteroid osteoporosis is preferable to treatment of established corticosteroid bone loss. Several large double-blind controlled clinical trials in patients with corticosteroid osteoporosis have recently been published that provide new insights into its treatment. Based upon available evidence, the rank order of choice for prophylaxis would be a bisphosphonate followed by a vitamin D metabolite or an oestrogen type medication. Calcium alone appears to be unable to prevent rapid bone loss in patients starting corticosteroids, especially with prednisolone doses at 10 mg a day or greater. If an active vitamin D metabolite is used, calcium supplementation should be avoided unless dietary calcium intake is low. Hormone replacement therapy should be considered if hypogonadism is present. Since vertebral fracture is a common and important complication of high dose corticosteroid therapy, these findings suggest that rapid bone loss and hence fractures, can be prevented by prophylactic treatment. Although the follow-up data is limited, it is likely that such therapy needs to be continued beyond 12 months whilst patients continue significant doses of corticosteroid therapy.

Glucocorticoid-induced osteoporosis

Glucocorticoids remain a key component in the management of many inflammatory disorders but the adverse consequences, especially on bone, can be devastating. The incidence of glucocorticoid-induced osteoporosis (GIO) may be as high as 50% after 6 months' treatment with steroids. This manifests itself as a 30 to 400% increase in the incidence of low trauma fractures. The incidence rates can be even greater in specific clinical settings such as following organ transplantation. The pathogenesis of glucocorticoid-induced osteoporosis remains complex and perplexing.The concomitant prescription of bone-active drugs for the prevention and treatment of GIO in the United Kingdom population remains low, despite the availability of effective therapies. In addition, there remain many unanswered questions about the pathogenesis of GIO and clinical management. These include identification of the optimum bone mineral density threshold at which to intervene with bone-active drugs, the dose or duration of exposure to steroid therapy that warrants intervention, and the demonstration of the efficacy of fracture prevention for different bone-active drugs or for a combination of these drugs.

Drug-induced rheumatic disorders: incidence, prevention and management

The purpose of this article is to review the causes, the clinical manifestations and the management of the more frequent drug-induced rheumatic disorders. These include: (i) articular and periarticular manifestations induced by fluoroquinolones, nonsteroidal anti-inflammatory drugs, injections of corticosteroids, and retinoids; (ii) multisystemic manifestations such as drug-induced lupus and arthritis induced by vaccination, Bacillus Calmette-Guerin therapy and cytokines; (iii) drug-induced disorders of bone metabolism (corticosteroid-induced osteoporosis, drug-induced osteomalacia and osteonecrosis); and (iv) iatrogenic complex regional pain syndromes. Disorders caused by nonpharmacological and rarely used treatments have been deliberately excluded. Knowledge of these drug-induced clinical symptoms or syndromes allows an earlier diagnosis and treatment, and earlier drug withdrawal if necessary. With the introduction of new medications such as the recombinant cytokines and antiretroviral treatments, the number of drug-induced rheumatic disorders is likely to increase.

Systemic corticosteroids inhibit bone healing in a rabbit ulnar osteotomy model

Prolonged systemic administration of corticosteroids causes osteoporosis and increased risk of fracture. Despite this well documented side effect of systemic corticosteroids, the effect of these compounds on fracture healing is not well defined. The goal of this study was to test the hypothesis that systemic corticosteroid therapy adversely affects fracture healing in a rabbit ulnar osteotomy model. Non-critical sized (1 mm) defects were created bilaterally in 18 adult female New Zealand White rabbits. Starting 2 months before operative intervention and continuing for 6 weeks during healing of the osteotomies, a subcutaneous dose of either sterile saline or prednisone (0.15 mg/kg) was administered daily. Serial radiographs of the forelimb were taken immediately postoperatively and weekly beginning the second week postoperatively. After killing at 6 weeks, only 3 of 20 limbs from animals treated with prednisone achieved radiographic union while 13 of 16 control limbs achieved union. The radiographic density of bone in the defect as well as callus size were greater in the control limbs than in the limbs from prednisone-treated animals. DEXA confirmed that the bone mineral content was lower in the ulnae of prednisone-treated rabbits both within the defect and in adjacent ulnar bone. Mechanical data indicated that osteotomies from rabbits chronically treated with prednisone were weaker than in controls. In this rabbit ulnar osteotomy model, chronic prednisone treatment clearly inhibited bone healing.

Glucocorticoid-induced osteoporosis

Glucocorticoid drugs interact with bone metabolism at many levels, but their principal action is to reduce osteoblast number and bone matrix synthesis. Virtually all patients receiving glucocorticoids in doses above 5 mg per day lose bone, the amount lost being dependent on the cumulative steroid dose. The risk of fracture is also related to the individual's initial bone density, which in turn reflects race, sex, age, menopausal status, body weight, smoking and the nature of any underlying illness. Bone density measurement and personal fracture history are the best predictors of future fracture risk. Steroid-induced bone loss is reversible, so measures to minimize the systemic steroid dose or to withdraw these drugs altogether should be pursued no matter how long an individual has been using them. Increasing the calcium intake to 1.5 g per day, encouraging them to stop smoking and take more exercise, and treating any vitamin D deficiency are sensible measures in all patients. In those at high risk, bisphosphonates are the best documented interventions, although sex hormone replacement is also effective and can be used alone or in addition to bisphosphonates.

Acute effects of etidronate on glucocorticoid-induced bone degradation

OBJECTIVES

To study the acute short-term effects on the biochemical parameters of calcium and bone homeostasis in post-menopausal women treated with a high dose of prednisone alone or with additional etidronate, before and during 5 days of treatment.

METHODS

Serum calcium, phosphorus, creatinine, alkaline phosphatase activity, osteocalcin, carboxy-terminal propeptide of type I procollagen (PICP), cross-linked carboxy-terminal telopeptide of type I collagen (ICTP), parathyroid hormone (PTH), 25-hydroxyvitamin D and urinary excretion of calcium over 24 h were measured before and during 5 days of treatment in 14 post-menopausal women treated with a high dose of prednisone (60 mg/day) alone (group A) or combined with cyclical etidronate (group B).

RESULTS

Significant differences from baseline were found in osteocalcin and urinary excretion of calcium in both groups and for ICTP in group B. Significant differences between groups were calculated at day 5 of the study for osteocalcin, ICTP and 24 h urine calcium excretion (P < 0.01). Urinary excretion of calcium over 24 h increased in group A (+14.7%; P < 0.05) and decreased in group B (-22.1%; P < 0.01). Osteocalcin levels decreased in group A (- 38.1%) and increased in group B (+27.4%; both P < 0.01). ICTP decreased only in group B (-19.4%; P < 0.01).

CONCLUSIONS

The results are consistent with the fact that etidronate is acutely able to prevent bone resorption due to corticosteroids. The increase in osteocalcin in the etidronate-treated group is a new feature. A direct or indirect (PTH, 1,25 vitamin D?) stimulatory effect of etidronate on the osteoblast cannot be excluded.

Glucocorticoid-induced osteoporosis

Endogenous cortisol excess and glucocorticoid (GC) treatment have a profound effect on bone metabolism, acting at many sites. The mechanism of GC action on bone turnover is complex and has not been elucidated completely. GCs increase bone resorption, inhibit bone formation and have an indirect action on bone by decreasing intestinal Ca2+ absorption, modifying vitamin D metabolism, and sustaining a marked hypercalciuria, with variable changes in plasma PTH levels; finally, GCs inhibit the gonadotropic and somatotropic axis. GC-induced osteoporosis is preventable, treatable and potentially reversible. The prevention and treatment of GC-induced osteoporosis include some general measures (as well as the use of the minimal effective dose of GC), Ca2+ and vitamin D supplementation and treatment with bone anabolic and antiresorptive agents. Recent trials suggest that bisphosphonates are an effective therapeutic tool in the treatment of GC-induced bone damage. Recent data on GC receptor-selective modulators indicate that these new molecules might induce only minimal bone loss while maintaining the typical anti-inflammatory properties of GC. Another new line of study for the prevention of GC-induced osteoporosis is the characterization of the individual's susceptibility to GC-induced bone damage.

Mechanism of bone loss after liver transplantation: A histomorphometric analysis

Organ transplantation is associated with increased bone loss and high fracture risk, but the pathophysiological mechanisms responsible have not been established. We have performed a histomorphometric analysis of bone remodeling before and 3 months after liver transplantation in 21 patients (14 male, 7 female) aged 38-68 years with chronic liver disease. Eight-micrometer undecalcified sections of trans-iliac biopsies were assessed using image analysis. Preoperatively, bone turnover was low with a tendency toward reduced wall width and erosion depth. The bone formation rate increased from 0.021 +/- 0.016 (mean +/- SD) to 0.067 +/- 0.055 microm2/microm/day after transplantation (p < 0.0002) and activation frequency from 0.24 +/- 0.21/year-1 to 0.81 +/- 0. 67/year-1 (p < 0.0001). No significant change was observed in wall width, but there was a trend toward an increase in indices of resorption cavity size. There was a small increase in osteoid seam width postoperatively (p< 0.02) and decrease in mineralization lag time (p < 0.001). No significant changes in indices of cancellous bone structure were observed in the postoperative biopsies. These results demonstrate a highly significant and quantitatively large increase in bone turnover in the first 3 months after liver transplantation. Although no significant disruption of cancellous bone structure was demonstrated during the time course of the study, the observed changes in bone remodeling predispose to trabecular penetration and may thus result in long-term adverse effects on bone strength.

The anesthetic isoflurane decreases ionized calcium and increases parathyroid hormone and osteocalcin in cynomolgus monkeys

The effects of anesthetics on calcium metabolism in cynomolgus monkeys were studied. Eight adult female cynomolgus monkeys were used in a crossover design. Blood was collected from each of the monkeys at four timepoints: (1) while conscious; (2) following induction of anesthesia with ketamine, ketamine and atropine, isoflurane, or no anesthetic; (3) at 30 min; and (4) 120 min thereafter. Four experiments were performed with a 1 week washout period between sessions, such that each monkey received each treatment. Potassium was lower in anesthetized monkeys than in those that remained conscious. Cortisol, although high, did not differ among anesthetic treatments. Ketamine and ketamine/atropine did not consistently affect ionized calcium or parathyroid hormone (PTH) concentrations. Isoflurane decreased ionized calcium (0.05 mmol/L), and increased PTH and osteocalcin twofold. The serum inorganic fluoride concentration was higher in monkeys anesthetized with isoflurane than with ketamine/atropine, which may partially account for the decrease in ionized calcium with isoflurane. The increases in PTH and osteocalcin are presumably secondary to the decrease in ionized calcium.

A UK Consensus Group on management of glucocorticoid-induced osteoporosis: an update

In the UK, over 250 000 patients take continuous oral glucocorticoids (GCs), yet no more than 14% receive any therapy to prevent bone loss, a major complication of GC treatment. Bone loss is rapid, particularly in the first year, and fracture risk may double. This review, based wherever possible on clinical evidence, aims to provide easy-to-use guidance with wide applicability. A treatment algorithm is presented for adults receiving GC doses of 7.5 mg day(-1) or more for 6 months or more. General measures, e.g. alternative GCs and routes of administration, and therapeutic interventions, e.g. cyclical etidronate and hormone replacement, are recommended.

Effects of short-term treatment with prednisolone and calcitriol on bone and mineral metabolism in normal men

To study the effects of treatment with glucocorticoid and calcitriol on biochemical markers of calcium and bone metabolism, 48 normal male volunteers (aged 21-54 years) were randomized to treatment for 7 days with either (A) prednisolone, 10 mg twice daily, (B) prednisolone, 10 mg twice daily, and calcitriol, 1 microg twice daily, (C) calcitriol 1 mg twice daily, or (D) placebo. The study period was 28 days. Renal calcium excretion increased (mean maximal increase +44.7%, p < 0.01) as well as serum parathyroid hormone (PTH) (max. +18.5%, p < 0.01) during prednisolone treatment. Concomitant treatment with calcitriol or calcitriol alone equally enhanced renal calcium excretion (max. +185.2%, p < 0.001) and decreased serum PTH (max. -43.1%, p < 0.001). Prednisolone administration was followed by prompt declines in markers of bone formation [serum osteocalcin (max. -34.7%, p < 0.001) and serum procollagen type I C-terminal propeptide (PICP) (max. -25.9%, p < 0.05)], whereas serum bone alkaline phosphatase (bone AP) remained unchanged. Calcitriol in combination with prednisolone attenuated the decrease in PICP (max. -8.9%, not significant), but it had no effect on osteocalcin (max. -40.1%, p < 0.001), and decreased bone AP (max. -22.2%, p < 0.05). Calcitriol alone increased osteocalcin (max. +37.8%, p < 0.03) and PICP (max. +26.0%, p < 0.05). Among markers of bone degradation, prednisolone suppressed serum C-terminal telopeptide of type I collagen (ICTP) (max. -28.4%, p < 0.001), but not the fasting renal excretion of hydroxyproline (OHP) and collagen type I N-terminal telopeptide (NTx). Calcitriol partially antagonized the decrease in ICTP (max. -17.2%, p < 0.001). Calcitriol alone had no effect on resorptive markers. Extraosseous matrix synthesis was suppressed by prednisolone evaluated by serum procollagen type III N-terminal propeptide (max. -30.8%, p < 0.001) and was not affected by concomitant treatment with calcitriol or calcitriol alone. In conclusion, short-term administration of prednisolone to healthy men leads to fast and protracted suppression of biochemical markers of bone formation and extraosseous connective tissue metabolism. The effect on bone was partially antagonized by simultaneous calcitriol treatment, and points toward a potential role of calcitriol in the prevention of steroid induced osteoporosis.

How do we manage specific types of osteoporosis?

Osteoporosis in children, adolescents and corticosteroid-treated patients represent a particular problem for clinicians. In children and adolescents, the main management question is whether any specific interventions can influence attainment of peak bone mass and so decrease the chance of osteoporosis in later adult life. The role of physical activity and calcium in particular are reviewed. In adolescence, osteoporosis is usually due to idiopathic juvenile osteoporosis or secondary to amenorrhoea or anorexia nervosa. These entities, as well as the management of corticosteroid-induced osteoporosis at all ages, are discussed.

Early increase in plasma parathyroid hormone levels following liver transplantation

BACKGROUND/AIMS

The pathogenesis of post-transplantation bone loss is poorly understood, although glucocorticoid therapy is believed to play an important role. In the present study we have measured plasma parathyroid hormone concentrations in the first few months after orthotopic liver transplantation, in order to examine the potential contribution of hyperparathyroidism to bone disease.

PATIENTS AND METHODS

Twenty-seven patients aged 32-54 years, 12 male, undergoing liver transplantation were studied prospectively before and for 3 months after operation. Plasma parathyroid hormone and serum 25-hydroxyvitamin D concentrations were measured by radioimmunoassay.

RESULTS

Plasma parathyroid hormone levels were normal in all but two patients prior to transplantation. There was a highly significant increase in plasma parathyroid hormone concentrations at 1 and 2 months (p < 0.0005 and 0.001, respectively, versus baseline); by 3 months, values were close to those obtained preoperatively. Serum 25-hydroxyvitamin D concentrations showed no significant change over the study period. However, 74% of the patients had subnormal values at baseline.

CONCLUSIONS

An early and transient increase in plasma parathyroid hormone after liver transplantation may be responsible for the high rates of bone loss which occur during the first few post-operative months. Prevention of post-transplantation bone disease is most likely to be achieved by peri-operative intervention with an anti-resorptive agent.

Changes in (markers of) bone metabolism during high dose corticosteroid pulse treatment in patients with rheumatoid arthritis

OBJECTIVE

To examine the effect of high dose corticosteroid pulse treatment (three times 200 mg dexamethasone intravenously in eight days) on calcium and bone metabolism in 17 consecutive patients with active rheumatoid arthritis (RA).

METHODS

Bone formation was quantified by measurement of serum alkaline phosphatase, osteocalcin, and carboxyterminal propeptide of type I procollagen (pro-I-CPP) concentrations. Bone resorption was measured by urinary excretion of calcium, hydroxyproline, (free and total) deoxypyridinoline (Dpyr), (free and total) pyridinoline (Pyr), and serum concentrations of the carboxyterminal cross linked telopeptide of type I collagen (I-CTP). Disease activity of RA was measured by erythrocyte sedimentation rate, C reactive protein, and Ritchie and Thompson joint scores.

RESULTS

Disease activity was initially high, and decreased during corticosteroid pulse treatment and the following five weeks. Osteocalcin, alkaline phosphatase, and pro-I-CPP concentrations were initially within normal limits, while I-CTP, Dpyr, and Pyr were increased. Osteocalcin and pro-I-CPP concentrations decreased (p < 0.01) during corticosteroid pulse treatment, but rapidly returned to baseline after the treatment. No changes were observed in alkaline phosphatase and urinary excretion of calcium and hydroxyproline. Bone resorption measured by serum I-CTP and urinary excretion of Pyr and Dpyr was unchanged or decreased (p < 0.05-0.01), depending on the time of measurement and the parameter measured.

CONCLUSIONS

In these patients with active RA, bone resorption was increased, while bone formation was within normal limits. During high dose corticosteroid pulse treatment, bone formation was only transiently decreased, while markers of bone resorption were unchanged or decreased. Because corticosteroid pulse treatment has only a short term negative effect on bone formation, and because it probably reduces bone resorption, at least partly as a result of the decreased disease activity, the effect of corticosteroid pulse treatment on bone may be assumed to be relatively mild.

Bone density change and biochemical indices of skeletal turnover

Although biochemical markers of skeletal turnover cannot replace bone density scanning for the diagnosis of osteoporosis, it is thought that they may help add to prediction of fracture risk and help determine adequacy of osteoporosis therapy. Nevertheless, whether biochemical markers in the serum or urine can predict individual rates of bone loss in the spine or hip region is unknown. We studied a heterogeneous group of women (n = 81) who were premenopausal, untreated postmenopausal, and estrogen-treated postmenopausal with baseline determination of body mass index (BMI), calcium intake, biochemical measurements, and serial bone densitometry over 3 years. Serum assays included bone Gla protein (BGP), total and bone-specific alkaline phosphatase (AP, BSAP), carboxyterminal propeptide of type I procollagen (PICP), carboxyterminal telopeptide of type I collagen (ICTP) and tartrate-resistant acid phosphatase (TRAP). Urine assays included hydroxyproline (OHP), calcium, total pyridinoline, and total deoxypyridinoline. Individual biochemical markers and calcium intake were modestly correlated with bone density changes but were inconsistent regarding the spine versus the hip. All of the formation variables were significantly correlated to spine density change (r = -0.24 to -0.49) whereas the only resorption variable that correlated was urine OHp/Cr (r = -0.31). The only formation variable that correlated with hip density change was serum PICP whereas all of the resorption variables except serum TRAP were correlated (r = -0.23 to -0.35). "High turnover" individuals were defined at those with levels of biochemical variables at least 1 SD above the mean young normal for each variable. Higher bone loss rates were seen in this group for several of the turnover markers compared with bone loss rates in all other individuals. However, the sensitivity of this "high turnover" status for identifying high bone losers did not exceed 60% for any of the variables. In untreated postmenopausal women, a model using urine OHp, serum ICTP, serum BSAP, and calcium intake was able to predict 42% of the variance of change in BMD of the lumbar spine. A model using BMI, serum ICTP, and serum BGP could predict 32% of the variance of change in BMD of the femoral neck. No combination of markers could predict variance in bone density change at either site in estrogenized women (premenopausal and estrogen-treated postmenopausal). We conclude that measuring individual serum and urine markers of bone turnover cannot accurately predict bone loss rates in the spine and hip; however, combinations of demographic and biochemical variables could predict some of the variance in untreated postmenopausal women. Biochemical markers cannot replace serial bone densitometry for accurate determination of change in bone mass at the most clinically relevant sites.

The systemic effect of intraarticular administration of corticosteroid on markers of bone formation and bone resorption in patients with rheumatoid arthritis

OBJECTIVE

To assess the effects of intraarticular (IA) corticosteroid use on bone metabolism in patients with rheumatoid arthritis (RA).

METHODS

Levels of the bone turnover markers, serum osteocalcin (BGP) and urinary pyridinoline (PYD), were monitored in RA patients for 4 weeks following a single IA administration of xylocaine alone or in combination with triamcinolone acetonide.

RESULTS

Levels of the bone resorption marker, PYD, did not show any significant change, whereas BGP levels were drastically decreased 1 day after IA administration of corticosteroid, and then returned to pretreatment levels by day 14. The efficacy of IA corticosteroid treatment lasted for 4 weeks.

CONCLUSION

Our results suggest that IA administration of corticosteroid has no net effects on bone resorption and only a transient systemic effect on bone formation. IA corticosteroid administration may be better for bone metabolism than continuous use of orally administered corticosteroid.

Intact parathyroid hormone levels are not elevated in glucocorticoid-treated subjects

To assess whether chronic glucocorticoid therapy results in a compensatory increase in parathyroid hormone (PTH), we measured intact PTH levels and other indices of mineral metabolism in 13 postmenopausal glucocorticoid-treated women and 16 normal age-matched controls. The glucocorticoid-treated women received a mean prednisone dose of 15.8 +/- 3.1 mg/day for 12.9 +/- 3.1 years. A linear regression analysis between intact PTH levels and a wide range of prednisone doses in these 13 glucocorticoid-treated women and 26 additional male and female subjects receiving chronic glucocorticoid therapy for a variety of rheumatic and pulmonary disorders (n = 39) was also performed. Intact PTH levels using the sensitive immunoradiometric assay (IRMA, Nichols Institute, San Juan Capistrano, CA) were comparable in the glucocorticoid-treated and normal control women (35.3 +/- 4.4 vs 31.3 +/- 3.2 ng/l, respectively) as wee the total calcium concentrations (9.67 +/- 0.12 vs 9.52 +/- 0.11 mg/dl). In the glucocorticoid-treated women, the 25-hydroxyvitamin D levels, measured by competitive protein assay were similar to those of the control subjects (29.2 +/- 2.8 vs 29.1 +/- 2.3 mg/ml), and no patient was treated with vitamin D in excess of 400 IU daily. In the combined 39 male and female patients, there were also no significant regression relationships between daily prednisone dose and intact PTH levels. Thus, secondary hyperparathyroidism does not accompany chronic oral glucocorticoid therapy in women on low to moderate doses of oral glucocorticoids. The lack of an elevation in intact PTH levels in the presence of chronic glucocorticoid therapy may represent an increased sensitivity of bone to PTH, or an alteration in the relationship between calcium and PTH, or both.

Oral 1,25-dihydroxyvitamin D administration in osteoporotic women: effects of estrogen therapy

Estrogen has been shown to modify calcium and skeletal homeostasis. In this study, we tested the ability of estrogen to influence the effects of short-term 1,25(OH)2D administration on biochemical indices of bone formation and resorption in a cross-sectional analysis of untreated (n = 10) and estrogen-treated (n = 14) osteoporotic women. Patients were given oral 1,25(OH)2D (Rocaltrol) 0.5 microgram twice a day for 5 days. Serum and urine were sampled at baseline and then 1 h after the first daily Rocaltrol dose for the 5 days of the study. 1,25(OH)2D levels rose similarly in both groups with plateaus reached by the third day of the investigation. Serum PTH levels decreased by the first sampling period (1 h after first Rocaltrol dose; p < 0.008 both groups) and continued to fall gradually in both groups. There were no changes in serum calcium but serum phosphorus rose by the second day (p < 0.05 both groups) and remained elevated throughout the remainder of the protocol. Serum bone Gla protein increased approximately 40% (p < 0.05) with no group differences. In contrast, total alkaline phosphatase and carboxy-terminal propeptide of type I collagen did not increase in either group. Furthermore, there were no significant increments in any bone resorption indicators, including serum tartrate-resistant acid phosphatase and cross-linked carboxy-terminal telopeptide of type I collagen, as well as urine hydroxyproline and pyridinoline. Serum IGF-1 levels also remained unchanged in both groups. We conclude that oral 1,25(OH)2D administration decreased 1-84PTH levels, probably due to a suppression of parathyroid production, and did not stimulate bone resorption.(ABSTRACT TRUNCATED AT 250 WORDS)