Julien Collette

PREVENTION OF POSTMENOPAUSAL BONE LOSS BY TILUDRONATE

76 healthy women, who had been menopausal for less than 96 months and who had never received any form of treatment to prevent bone loss, were entered into a randomised double-blind study. For the first 6 months, half the patients received tiludronate 100 mg daily, while the others received placebo. During the second 6 months, all patients received placebo. Bone mineral density of the lumbar spine decreased significantly by 2.1% (SE 0.8%) in the placebo group and did not significantly change in the tiludronate group (+1.33 [0.8]%). The difference in response between the groups was significant, as were the differences between values for corrected urinary hydroxyproline and calcium. Treatment with tiludronate was not followed by increased secretion of parathyroid hormone. A 6 month course of oral tiludronate may counteract postmenopausal bone loss for at least a year by decreasing bone resorption.

Value of biomarkers in osteoarthritis: current status and perspectives.

Osteoarthritis affects the whole joint structure with progressive changes in cartilage, menisci, ligaments and subchondral bone, and synovial inflammation. Biomarkers are being developed to quantify joint remodelling and disease progression. This article was prepared following a working meeting of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis convened to discuss the value of biochemical markers of matrix metabolism in drug development in osteoarthritis. The best candidates are generally molecules or molecular fragments present in cartilage, bone or synovium and may be specific to one type of joint tissue or common to them all. Many currently investigated biomarkers are associated with collagen metabolism in cartilage or bone, or aggrecan metabolism in cartilage. Other biomarkers are related to non-collagenous proteins, inflammation and/or fibrosis. Biomarkers in osteoarthritis can be categorised using the burden of disease, investigative, prognostic, efficacy of intervention, diagnostic and safety classification. There are a number of promising candidates, notably urinary C-terminal telopeptide of collagen type II and serum cartilage oligomeric protein, although none is sufficiently discriminating to differentiate between individual patients and controls (diagnostic) or between patients with different disease severities (burden of disease), predict prognosis in individuals with or without osteoarthritis (prognostic) or perform so consistently that it could function as a surrogate outcome in clinical trials (efficacy of intervention). Future avenues for research include exploration of underlying mechanisms of disease and development of new biomarkers; technological development; the ‘omics’ (genomics, metabolomics, proteomics and lipidomics); design of aggregate scores combining a panel of biomarkers and/or imaging markers into single diagnostic algorithms; and investigation into the relationship between biomarkers and prognosis.

The Effect of Sodium Monofluorophosphate Plus Calcium on Vertebral Fracture Rate in Postmenopausal Women with Moderate Osteoporosis. A Randomized, Controlled Trial

During the past 30 years, fluoride salts have been studied as agents for the treatment of osteoporosis in postmenopausal women with the expectation that stimulation of osteoblastic proliferation and activity and the subsequent increase in bone formation would be followed by a significant decrease in fracture rates [1-3]. It is widely accepted that fluoride is effective in increasing trabecular bone mass in the spine [4]. However, discrepant results have been obtained from studies evaluating the effects of fluoride salts on cortical bone mass and, more important, on the quality of the newly synthesized bone and on vertebral and nonvertebral fracture rates [5-9]. These differences are probably related to differences in fluoride dose, formulation, and regimen; duration of therapy; and treated populations. Because bone-forming agents such as fluoride are expected to work mainly by increasing bone mineral content without restoring disrupted bone tissue integrity, they may be particularly useful in patients with mild to moderate osteoporosis in whom the microarchitecture of the skeleton is not excessively damaged. To test this hypothesis, we studied the effect of low-dose fluoride (sodium monofluorophosphate [MFP]) plus calcium in a 4-year, randomized, double-blind, controlled clinical trial in postmenopausal women with moderately low bone mineral density (BMD) of the spine. Methods Patients Our study included white postmenopausal women with lumbar (L2 to L4) BMD of the spine below the 90th percentile of the distribution of BMD of the spine seen in Belgian women with osteoporosis [10, 11]. This degree of bone loss corresponded to a T-score of 2.5,in accordance with the operational definition of osteoporosis recently proposed by a World Health Organization study group [12]. Patients were included in the study regardless of whether they had previously had vertebral or nonvertebral fractures; most of the patients were thought to be free of vertebral fractures at enrollment. Previous hip fracture was an exclusion criterion. All patients were free of other causes of osteoporosis, such as diseases or medications known to interfere with bone metabolism; none had been treated with any drug for postmenopausal osteoporosis; and no such treatment was allowed during the study. Hormone replacement therapy was continued, for ethical reasons, in women for whom it had been prescribed before enrollment for purposes other than bone therapy. Randomization was not stratified with respect to hormone replacement therapy. Patients with bone diseases other than osteoporosis, renal insufficiency, hypochlorhydria, or severe chronic disorders that could have interfered with the study were excluded. Study Design Patients were randomly assigned in a blinded manner to one of two therapeutic groups. Every day for 4 years, they received either two chewable tablets that each contained 76 mg of MFP (10 mg of equivalent fluoride [fluoride ion]) and 1250 mg of calcium carbonate (500 mg of equivalent calcium) or two chewable tablets that each contained 1250 mg of calcium carbonate alone and were similar in appearance to the MFP-plus-calcium tablets. Total daily dosages, therefore, were 20 mg of equivalent fluoride plus 1000 mg of calcium in the MFP-plus-calcium group and 1000 mg of calcium in the calcium-only group. The two tablets were taken at different meals. We determined compliance at each study visit by asking each patient for the number of days on which she had not taken the tablets and by counting the unused tablets. Compliance was expressed as the percentage of tablets taken (100% if the patient had taken all of the tablets). Patients received randomization numbers sequentially. Randomization was computer generated in blocks of four according to a strict standard operating procedure by persons who had no contact with the persons in the center who assigned patients to study groups. The randomization code was kept at the study sponsors facility under secure conditions that were detailed in writing. The clinical research center was given opaque, sealed envelopes, each of which contained the code for one patient. Treatment assignment and other relevant information were thus concealed and were to be revealed only in the case of a medical emergency. Blinding was achieved by using the following procedures. First, the persons who did the visual readings of the spine radiographs saw the codes only after the results were analyzed. Second, the data were analyzed under blinded conditions: that is, a first analysis was done with groups A and B; the analysts did not know which group had received which treatment. Efficacy Evaluation Criteria The primary end point was the number of patients with new vertebral fractures during the 4-year treatment period, in accordance with recently published guidelines for the evaluation of drugs to be registered in Europe for the prevention or treatment of osteoporosis [13]. Standardized lateral radiographs of the thoracic and lumbar spine were obtained at enrollment and at each year of follow-up, for up to 4 years, in a single radiology center. The radiographs were sent to an independent assessor. Films were digitized, and the anterior, middle, and posterior heights of each vertebral body from the fourth thoracic (T4) to the fifth lumbar (L5) were determined (accuracy of the digitizer, 0.025 mm) by a computer program. This was done by persons with no knowledge of treatment assignment or film sequence. A new vertebral fracture (incident fracture) was defined as a reduction of at least 20% and an absolute decrease of at least 4 mm in any height of at least one vertebral body between enrollment and the latest follow-up film. All fractures, including borderline cases, were confirmed by visual reading. This definition was applied to vertebrae that were not fractured at enrollment, whereas fractures present at enrollment were determined on the digitized enrollment radiographs by using the Melton-Riggs 25% unadjusted algorithm [14]. The possible progression of such baseline lesions was assessed with the Vertebral Deformity Index obtained for each vertebra (T5 through L5); these were then summed to obtain the Spine Deformity Index, a continuous measure of vertebral deformities [15]. The Spine Deformity Index was also used as a secondary variable in patients with incident or progressing vertebral deformities, in whom it was expressed as the mean change between the last observed value and baseline. Bone mineral density was measured by using dual-energy x-ray absorptiometry on the same densitometer (Hologic QDR 1000, Waltham, Massachusetts) at 6-month intervals at the lumbar spine (L2 to L4) and the nondominant hip (total hip) after previously described and validated procedures were performed [11, 16]. In our hands, the long-term coefficients of variation of dual-energy x-ray absorptiometry are 0.8% for BMD of the spine and 1.1% for BMD of the total hip [17]. Biochemical determinations of bone remodeling were made at 6-month intervals. Bone formation was assessed by radioimmunoassay of serum bone-specific alkaline phosphatase (Ostase, Hybritech, San Diego, California). For bone resorption, we measured the ratio of urinary hydroxyproline to creatinine on the second fasting urine spot (2-hour morning urine) (Hypronostikon kit, Organon Technika, Oss Boxtel, the Netherlands). All peripheral (nonvertebral) fractures that occurred during the study were recorded independently of the nature and severity of the trauma that may have determined them. Statistical Analysis All analyses were done according to the intention-to-treat approach: that is, all patients who had at least one valid measurement after randomization were considered in the analysis, whether they were still taking the study drug or not. In the case of drop-out and, thus, discontinuation of therapy with the study medication, the patient was invited to return to the clinic at annual intervals (for 4 years, if possible) so that the radiography necessary to record outcome could be done. An exact-significance chi-square test was done to compare the number of patients with new vertebral fractures in the two groups. We calculated 95% CIs for vertebral fracture rates in each study group and for the difference in rates between the two groups, along with the point estimates of these rates. These rates were also expressed in terms of the number needed to treat for 4 years to prevent one fracture, including values for the lower and upper bounds of the 95% CIs. Changes in the Spine Deformity Index in patients with incident or progressing vertebral deformities were compared by analysis of variance. Analysis of variance for repeated measurements was used to compare the absolute values for BMD of the spine over the course of the study in the two groups. Analysis of variance for repeated measurements was also done to compare BMD of the total hip and percentage changes in biochemical markers of bone remodeling throughout the study. All P values are two-tailed. All statistical analyses were done with the SPS/WIN 6.2 statistical package (SPS, Inc., Chicago, Illinois). Role of Study Sponsor The trial was approved by the Ethical Committee of Liege University (registration no. 90/43-1262 of 14 May 1990), and all patients gave full informed consent before inclusion. The Rotta Research Group, which markets MFP and calcium combinations in Germany, Italy, and other countries, provided the drugs and funding for the study. Scientists from the Rotta Research Group were directly involved in the design, monitoring, and data management of the study and agreed to be listed as authors. However, the Rotta Research Group as a corporate entity had no control over the decision to approve or submit the manuscript for publication. Results Two hundred patients were enrolled in the study. The characteristics of the entire patient sample (100 patients were assigned to each group) at enrollment are shown in Table 1. The

Prevalence of vitamin D inadequacy in European postmenopausal women.

ABSTRACT Objective: Inadequate vitamin D level is associated with secondary hyperparathyroidism and increased bone turnover and bone loss, which in turn increases fracture risk. The objective of this study is to assess the prevalence of inadequate serum vitamin D levels in postmenopausal European women. There are no clear international agreements on what constitutes a level of vitamin D inadequacy, but recent publications suggest that the circulating level of vitamin D should be over 80 nmol/L or at least between 50 and 80 nmol/L. Material and methods: Assessment of 25-hydroxyvitamin D [25(OH)D] was performed in 8532 European postmenopausal women with osteoporosis or osteopenia. European countries included France, Belgium, Denmark, Italy, Poland, Hungary, United Kingdom, Spain and Germany. Two cut-offs of 25(OH)D inadequacy were fixed : < 80 nmol/L and < 50 nmol/L. Results: Mean (SD) age of the patients was 74.2 (7.1) years, body mass index was 25.7 (4.1) kg/m². Level of 25(OH)D was 61.0 (27.2) nmol/L. There was a highly significant difference of 25(OH)D level across European countries ( p < 0.0001). The lowest level of 25(OH)D was found in France [51.5 (26.1) nmol/L] and the highest in Spain [85.2 (33.3) nmol/L]. In the whole study population, the prevalence of 25(OH)D inadequacy was 79.6% and 32.1% when considering cut-offs of 80 and 50 nmol/L, respectively and when considering patients aged less than 65 years, the prevalence reached 86% (cut-off of 80 nmol/L) and 45% (cut-off of 50 nmol/L). Conclusion: This study indicates a high prevalence of vitamin D [25(OH)D] inadequacy in European postmenopausal women. The prevalence could be even higher in some particular countries. A greater awareness of the importance of vitamin D inadequacy is needed to address this public health problem.

Osteoarthritis, magnetic resonance imaging, and biochemical markers: a one year prospective study

Objective: To investigate the relation between biochemical markers of bone, cartilage, and synovial remodelling and the structural progression of knee osteoarthritis. Methods: 62 patients of both sexes with knee osteoarthritis were followed prospectively for one year. From magnetic resonance imaging (MRI), done at baseline and after one year, the volume and thickness of cartilage of the femur, the medial tibia, and the lateral tibia were assessed. A whole organ magnetic resonance imaging score (WORMS) of the knee was calculated for each patient at baseline and at the one year visits. This score consists in a validated, semiquantitative scoring system for whole organ assessment of the knee in osteoarthritis using MRI. Biochemical markers (serum hyaluronic acid, osteocalcin, cartilage glycoprotein 39 (YKL-40), cartilage oligomeric matrix protein (COMP), and C-telopeptide of type I collagen (CTX-I), and urine C-telopeptide of type II collagen (CTX-II)) were measured at baseline and after three months. Results: Baseline markers were not correlated with one year changes observed in cartilage volume and thickness. However, an increase in CTX-II after three months was significantly correlated with a one year decrease in mean thickness of medial tibial and lateral tibial cartilage. Patients in the highest quartile of three month changes in CTX-II experienced a mean loss of 0.07 (0.08) mm of their medial thickness, compared with a mean increase of 0.05 (0.19) mm for patients in the lowest quartile (p = 0.04) Multiple regression analysis showed that high baseline levels of hyaluronic acid are predictive of a worsening in WORMS (p = 0.004). Conclusions: These results suggest that a single measurement of serum hyaluronic acid or short term changes in urine CTX-II could identify patients at greatest risk of progression of osteoarthritis.

Propofol Protects Cultured Rat Hippocampal Neurons against N-Methyl-D-Aspartate Receptor-Mediated Glutamate Toxicity

The effect of propofol on the toxicity induced by glutamate (GLU), N-methyl-D-aspartate (NMDA), kainate (KA), and amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) was investigated on cultured fetal rat hippocampal neurons. The degree of neuronal injury was quantified by measuring the release of the neuron-specific enolase (NSE) into the culture media. The toxicity induced by brief exposure to GLU (10(-4) M) or to NMDA (10(-4) M) was significantly reduced by propofol, whereas that elicited by KA, AMPA (10(-4) M), or long GLU exposure was unaffected. In conclusion, high concentrations of propofol significantly attenuate NMDA receptor-mediated glutamate neurotoxicity in vitro. Further studies are needed to confirm this beneficial effect in vivo and to evaluate propofol as a neuroprotective anesthetic agent in pathologies involving glutamate release and NMDA-mediated toxicity.

Relationship between whole plasma calcitonin levels, calcitonin secretory capacity, and plasma levels of estrone in healthy women and postmenopausal osteoporotics.

The exact role of calcitonin (CT) in the pathogenesis of postmenopausal osteoporosis remains unknown. Whole plasma calcitonin (iCT) basal levels, metabolic clearance rate (MCR), and production rate (PR) of CT were measured in 9 premenopausal and 16 postmenopausal women, including 11 osteoporotics (OP). Basal iCT levels were statistically lower in postmenopausal women than in the premenopausal group (P less than 0.01) and strongly correlated (r = 0.72; P less than 0.001) with estrone circulating levels (E1). MCR were similar in all groups. PR were similar in eugonadal women between 22 (mean +/- SD = 30.9 +/- 9.9 micrograms/d) and 37 yr (mean +/- SD = 25.5 +/- 11.1 micrograms/d) premenopausal women. In healthy postmenopausal women PR were reduced, but not significantly (mean +/- SD = 19.5 +/- 6.95 micrograms/d), whereas osteoporotic patients presented a highly significant reduction of CT PR (mean +/- SD = 9.8 +/- 4 micrograms/d) (P less than 0.01). Because there is a strong relationship between E1 and PR (r = 0.64; P less than 0.001), CT secretory capacity appears to be modulated by estrogen circulating levels. This modulation leads to a menopause-related decrease in iCT. In osteoporotics, an independent impairment of CT production drastically lowers PR and basal iCT levels. CT might be one of the determining factors in the pathogenesis of postmenopausal osteoporosis.

Bone resorption in post-menopausal women with normal and low BMD assessed with biochemical markers specific for telopeptide derived degradation products of collagen type I

Biochemical markers of bone resorption can be used clinically to predict the risk of osteoporosis-related fractures (prognostic tool) and to assess the response of an osteoporotic patient to an antiresorptive therapy (monitoring tool). Our aim was to assess the ability of four currently marketed biochemical markers of bone resorption, based on the measurement of degradation products from collage type I telopeptides to monitor the elevated resorption associated with menopause. Women (846) were stratified for menopause, age, and bone mineral density and the following markers were measured: urinary cross-linked N-telopeptides of type I collagen (NTx), the levels of breakdown products of type I collagen C-telopeptides in serum (S-CTx), and in urine, by ELISA (U-CTx-E), and RIA (U-CTx-R). Furthermore, the ratio (alpha/beta) between the alphaL form of CTx measured in the CTx RIA and the betaL form measured in the ELISA was calculated. The mean difference was calculated for each marker in women with osteopenia (Op) or osteoporosis (PMO) (WHO definition) compared with healthy premenopausal (Pre) women and postmenopausal (N Post) women with normal bone mass. Serum CTx showed the highest elevation in post- compared with premenopausal women. All marker values were significantly higher in Op and PMO subjects compared with both Pre and to N Post women. Compared with premenopausal values, the largest elevation in both Op and PMO women was observed for serum CTx. Compared with N Post, urine NTx showed the highest increase in OP subjects. The alpha/beta CTx ratio was elevated in post- compared with Pre women, but there was no difference in the ratio among N Post, Op, or PMO women. In conclusion, postmenopausal women showed elevated turnover with all bone resorption markers, but with substantial individual variation in resorption levels. Furthermore, the turnover process in postmenopausal women appears to be quantitatively different from the premenopausal stage, apparent as altered alpha/beta CTx ratios.

Interest of biochemical markers of bone turnover for long-term prediction of new vertebral fracture in postmenopausal osteoporotic women

OBJECTIVE To analyse the interest of baseline levels and short-term (3-months) changes in serum osteocalcin (BGP), serum bone-specific alkaline phosphatase (BALP) and urinary C-telopeptide of type I collagen/creatinine ratio (U-CTX) to predict 3-years changes in bone mineral density (BMD) and spinal deformity index (SDI) in postmenopausal osteoporotic women. METHODS Data were derived from a cohort of 603 osteoporotic women corresponding to the placebo arm of a 3-years prospective, double-blind study. RESULTS Baseline values of BALP, BGP and U-CTX were negatively and significantly correlated with baseline spinal BMD. Significant correlations were also observed between the changes in BMD observed after 36 months at the spine and baseline BALP (r=0.20, P=0.0001), BGP (r=0.09, P=0.05) and U-CTX (r=-0.11, P=0.02). At 3 years, 71 women (15.9%) showed an increase in their SDI, corresponding to the occurrence of at least one new vertebral deformity. Baseline values of the four bone turnover markers (BTM) were not significantly related to the occurrence of new vertebral deformities. However, when considering the changes in the BTM observed after 3-months of follow-up, BGP (P=0.003) and U-CTX (P=0.047) were identified as significant predictors of an increase of SDI. The associated odds ratios (95% confidence interval (CI)) were 10.922 (2.218-53.78) for unit changes of log BGP and 1.369 (1.003-1.867) for unit changes of logU-CTX. The relative risk (RR) (IC 95%) of having a new vertebral fracture over 36 months was 0.31 (0.15-0.65) when being in the lowest quartile of 3-months changes in BGP as compared with the highest. CONCLUSION We conclude that two sequential measurements of BGP and U-CTX performed at 3-months intervals could be of interest to identify postmenopausal osteoporotic women with the highest risk to present new vertebral deformities.

Role of biochemical markers of bone turnover as prognostic indicator of successful osteoporosis therapy

Most of the currently available anti-osteoporosis medications promptly and significantly influence the rate of bone turnover. Biochemical markers of bone turnover now provide a high sensitivity to change, allowing the detection of these bone turnover changes within a couple of weeks. Since the anti-fracture efficacy of inhibitors of bone resorption or stimulators of bone formation appears to be largely independent of baseline bone turnover, biochemical markers do not appear to play a significant role in the selection of one particular drug, for an individual patient. However, there are consistent data showing that short-term changes in biochemical markers of bone turnover may be significant predictors of future changes in bone mineral density or fracture reduction, hence suggesting that bone turnover markers play a significant role in the monitoring of anti-osteoporosis therapy.