Jean-Pierre Devogelaer

Evidence-based guidelines for the use of biochemical markers of bone turnover in the selection and monitoring of bisphosphonate treatment in osteoporosis: a consensus document of the Belgian Bone Club

Objectives:u2002 To review the clinical value of bone turnover markers (BTM), to initiate and/or monitor anti‐resorptive treatment for osteoporosis compared with bone mineral density (BMD) and to evaluate suitable BTM and changes in BTM levels for significance of treatment efficiency.

Low bone mass in hypogonadal males. Effect of testosterone substitution therapy, a densitometric study

Sixteen (16) male patients who were suffering from hypogonadism but who were free from bone symptoms were recruited from the Andrology Clinic. Their bone mineral density (BMD) was assessed by single photon absorptiometry in the non-dominant radius, at both the distal radius (DR) (27% trabecular bone) and the midshaft radius (MR) (90% cortical bone). Measurements were carried out before and during testosterone substitution therapy. BMD was found to be lower in the subjects than in the controls, to a similar extent at both the DR (0.47 +/- 0.02 g/cm2, i.e. 83.1 +/- 4.3% of the value in the controls, or Z score -1.42 +/- 0.39; P less than 0.01) and the MR (0.68 +/- 0.02 g/cm2, i.e. 87.8 +/- 2.4% of the value in the controls, or Z score -1.49 +/- 0.33; P less than 0.01). There was no correlation between testosterone levels and BMD at either the DR or the MR at the beginning of the study. Following testosterone substitution therapy, bone mineral content (BMC) increased significantly at the DR (+5.9 +/- 1.4% per year; P less than 0.01) and at the MR (+1.1 +/- 0.9% per year; P less than 0.01). If the study is limited to the subjects who had achieved full bone age maturity before the start of therapy, the bone gain remains significant only at the DR, a site with a sizeable proportion of trabecular bone.

Inhomogeneity of Human Vertebral Cancellous Bone: Systematic Density and Structure Patterns Inside the Vertebral Body

In the spine, cancellous bone quality is usually assessed for the whole vertebral body in a transverse central slice. Correct identification and assessment of the weakest parts of the cancellous bone may lead to better prediction of fracture risk. The density and structural parameters were systematically investigated inside the thoracic (T-9), thoracolumbar (T12-L1), and lumbar (L-4) vertebral bodies of nine subjects. On both sides of the median sagittal plane, anterior and posterior 8.2 mm vertical cores were harvested in the thoracic vertebra. In the thoracolumbar and lumbar vertebrae, external samples were also cored. Peripheral quantitative computed tomographic (pQCT) density analysis of the 136 cores was performed at four different levels, from the lower to the upper endplate. The relatively thin slice thickness (300 microm) and small pixel size (70 microm x 70 microm) was considered sufficient to investigate the structural parameters on the four transverse slices and in the sagittal and coronal planes (total of 816 images). Using a constant threshold a binary image was generated and the morphometric data were extracted. The binary image was further skeletonized and classical strut analysis was performed. Cancellous bone density was 20% higher in the posterior cores than in the anterior and external cores. Moreover, clear vertical inhomogeneity was noted because the lowest half of the vertebral body presented lower density than the upper half (differences ranging from 25% to 15%). All structural parameters were strongly dependent on the location of the measurement. Structural differences between anterior, posterior, and external areas were mild and followed the density patterns. On the other hand, vertical inhomogeneity of the structural parameters was important. For example, in the thoracolumbar and lumbar vertebrae, the numbers of nodes or node-to-node struts were almost twofold higher in the inferior half than in the superior half (p < 0.01), whereas trabecular thickness and number of free-ends presented a center/close-to-endplate structural pattern, with central trabeculae being 15% thicker (p < 0.05) and presenting 30% fewer free-ends (p < 0.01) than the close-to-endplate ones. Variability of density and structural parameters was high and a substantial part of this variability could be explained by the place inside the vertebral body where the measurement was made. The weak part was not in the center of the body but in its upper half where the lower density did not seem to be compensated by a higher structural architecture. Further clinical investigation could enhance fracture prediction by tracking and focusing on the weakest part of the vertebral body.

Beneficial effects of creatine supplementation in dystrophic patients

The effect of creatine (Cr) supplementation on muscle function and body composition of 12 boys with Duchenne muscular dystrophy and three with Becker dystrophy was evaluated by a randomized double‐blind cross‐over study (3 g Cr or maltodextrin daily for 3 months, with wash‐out period of 2 months). After placebo, no change was observed in maximal voluntary contraction (MVC) and resistance to fatigue, whereas total joint stiffness (TJS) was increased by ∼25% (P < 0.05). The patients receiving Cr did not show any change in TJS, improved MVC by 15% (P = 0.02), and almost doubled their resistance to fatigue (P < 0.001). In patients still independent of a wheelchair (n = 5), bone mineral density increased by 3% (P < 0.05), and urinary excretion of collagen type I cross‐linking N‐telopeptide declined to about one third (P < 0.001) after Cr. No adverse effect was observed. Thus, Cr may provide some symptomatic benefit in these patients. Muscle Nerve 27: 604–610, 2003

Fluoride effects on bone formation and mineralization are influenced by genetics.

INTRODUCTIONnA variation in bone response to fluoride (F(-)) exposure has been attributed to genetic factors. Increasing fluoride doses (0 ppm, 25 ppm, 50 ppm, 100 ppm) for three inbred mouse strains with different susceptibilities to developing dental enamel fluorosis (A/J, a susceptible strain; SWR/J, an intermediate strain; 129P3/J, a resistant strain) had different effects on their cortical and trabecular bone mechanical properties. In this paper, the structural and material properties of the bone were evaluated to explain the previously observed changes in mechanical properties.nnnMATERIALS AND METHODSnThis study assessed the effect of increasing fluoride doses on the bone formation, microarchitecture, mineralization and microhardness of the A/J, SWR/J and 129P3/J mouse strains. Bone microarchitecture was quantified with microcomputed tomography and strut analysis. Bone formation was evaluated by static histomorphometry. Bone mineralization was quantified with backscattered electron (BSE) imaging and powder X-ray diffraction. Microhardness measurements were taken from the vertebral bodies (cortical and trabecular bones) and the cortex of the distal femur.nnnRESULTSnFluoride treatment had no significant effect on bone microarchitecture for any of the strains. All three strains demonstrated a significant increase in osteoid formation at the largest fluoride dose. Vertebral body trabecular bone BSE imaging revealed significantly decreased mineralization heterogeneity in the SWR/J strain at 50 ppm and 100 ppm F(-). The trabecular and cortical bone mineralization profiles showed a non-significant shift towards higher mineralization with increasing F(-) dose in the three strains. Powder X-ray diffraction showed significantly smaller crystals for the 129P3/J strain, and increased crystal width with increasing F(-) dose for all strains. There was no effect of F(-) on trabecular and cortical bone microhardness.nnnCONCLUSIONnFluoride treatment had no significant effect on bone microarchitecture in these three strains. The increased osteoid formation and decreased mineralization heterogeneity support the theory that F(-) delays mineralization of new bone. The increasing crystal width with increasing F(-) dose confirms earlier results and correlates with most of the decreased mechanical properties. An increase in bone F(-) may affect the mineral-organic interfacial bonding and/or bone matrix proteins, interfering with bone crystal growth inhibition on the crystallite faces as well as bonding between the mineral and organic interface. The smaller bone crystallites of the 129P3/J (resistant) strain may indicate a stronger organic/inorganic interface, reducing crystallite growth rate and increasing interfacial mechanical strength.

Bone density and markers of bone remodeling in type 1 male diabetic patients

AIMSnTo assess the prevalence and severity of bone disease in type 1 diabetic patients and to determine serum markers of bone remodeling as well as their relationship with bone mineral density (BMD).nnnMETHODSnBMD [by dual energy x-ray absorptiometry (DXA)] and serum markers of bone remodeling [osteocalcin, c-terminal telopeptide of type I collagen (CTX)], leptin and osteoprotegerin (OPG) were measured in 42 adult males with type 1 diabetes. Twenty-four non-diabetic subjects served as controls.nnnRESULTSnIn 40% of the patients, osteopenia at the lumbar spine (L1-L4) and/or at the left hip was found, and 7% met criteria for osteoporosis. L1-L4 BMD z-score was correlated with age (r=0.365, P=0.018) and a similar trend was observed at left hip. L1-L4 BMD z-score was negatively correlated with CTX and osteocalcin (r=-0.343, P=0.028; r=-0.376, P=0.024, respectively). A significant correlation was evidenced between BMD z-score at both lumbar spine and left hip and leptin values (r=0.343, P=0.03; r=0.395, P=0.012, respectively) but after adjustment for weight this correlation was no longer significant. Osteocalcin, CTX and leptin concentrations were comparable between patients and controls, while OPG concentrations tend to be higher in diabetic subjects (P=0.08). CTX was negatively correlated with age (r=-0.390, P=0.012) and positively correlated with osteocalcin (r=0.696, P<0.001). OPG was positively correlated with age (r=0.507, P=0.001).nnnCONCLUSIONnOur results suggest that in diabetic subjects osteopenia is a relatively frequent complication but bone loss is attenuated with age progression. Whether this is also mediated by OPG and/or leptin remains to be confirmed.

Oral pamidronate prevents high-dose glucocorticoid-induced lumbar spine bone loss in premenopausal connective tissue disease (mainly lupus) patients.

Glucocorticoid (GC)-induced osteoporosis contributes to chronic damage in patients suffering from connective tissue diseases (CTD) such as systemic lupus erythematosus (SLE). In this study, performed in an highly selected cohort of premenopausal female CTD (mostly lupus) patients, given high-dose GC therapy for severe disease, we show that lumbar spine bone loss can be averted by treatment with oral disodium pamidronate combined with calcium salts and vitamin D3 supplements and not by calcium salts and vitamin D3 supplements alone. We stress the need for optimal GC-induced bone loss prevention therapy in premenopausal patients, a too often neglected issue in patients whose survival has dramatically improved over the last decades.

Long-Term Effects on Bone Mineral Density of Different Therapeutic Schemes for Acute Lymphoblastic Leukemia or Non-Hodgkin Lymphoma during Childhood

Background: Little is known regarding long-term bone deficit in relationship with the modalities of cancer therapy among survivors of childhood malignancy. Methods: Bone mineral density (BMD) was evaluated at lumbar spine (LS), total hip and femoral neck in 89 patients (44 men) more than 5 years after remission of childhood acute lymphoblastic leukemia (ALL) or non-Hodgkin lymphoma (NHL). The patients had received chemotherapy (group I; n = 41), chemotherapy and cranial irradiation (group II; n = 32), or bone marrow transplantation (BMT) with total body irradiation (TBI) (group III; n = 16). All patients had received methylprednisolone and 47 additional dexamethasone treatment. Results: A reduced BMD at any site was observed in 44 of the 89 patients, more frequently in men (66%) than women (33%) (p < 0.001). In comparison with group I, mean BMD was significantly lower at all sites in group II and at the total hip and femoral neck in group III. A multivariate analysis showed independent significant influences of male gender at LS (p < 0.001) and of type of treatment and dexamethasone at the hip (p < 0.05). Conclusions: A low bone mass is frequently observed in adult survivors of childhood ALL and NHL, and is associated with male gender at the LS and with dexamethasone treatment, cranial irradiation and BMT/TBI at the hip.

Evaluation of bone mineral density after renal transplantation under a tacrolimus-based immunosuppression: a pilot study.

BACKGROUNDnProgressive bone loss consistently complicates renal transplantation (TP) in patients given an immunosuppression including prednisolone. The adjunction of cyclosporine in the immunosuppressive regimen does not reverse the negative impact of renal TP on the skeleton. The post-transplant effect of tacrolimus on bone mass is still unknown.nnnMETHODSnWe evaluated the evolution of bone mineral density (BMD) and various biochemical markers over the first 12 months following renal TP in 23 patients given an immunosuppression combining tacrolimus and low-dose prednisolone. BMD of lumbar spine, total hip and hip subregions was measured by dual-energy X-ray absorptiometry within the first 15 days and 1 year after TP.nnnRESULTSnAt the time of TP, the average BMD was low in both the lumbar spine and the hip. After TP, a normalization of serum creatinine and a decrease in serum phosphate and iPTH levels occurs. Serum alkaline phosphatase level significantly rose transiently within the first 6 months and decreased thereafter. At 1 year post TP, BMD remained unchanged in the lumbar and in the trochanter subregions and rose in the other sites. BMD increased by at least 2% in 8, 13, 10 and 10 out of the 23 patients in the lumbar, neck, trochanter and total hip subregions, respectively. No correlation was found between evolution in BMD and age, sex, dialysis duration, level of hyperparathyroidism, prednisolone and tacrolimus cumulative intake and prescription of calcium, vitamin D or hormone replacement therapy.nnnCONCLUSIONSnAn immunosuppression combining tacrolimus and low-dose prednisolone might avoid the usual post-TP bone loss. Further randomized double-blind studies evaluating a larger cohort of patients should be undertaken to compare the effect of cyclosporine and tacrolimus on bone mass.

Biologicals in Osteoporosis: Teriparatide and Parathyroid Hormone in Women and Men

Osteoporosis is characterized by the occurrence of a host of fractures. According to densitometric values, an operational definition for osteoporosis corresponds to a loss of 25% to 30% (−2.5 T-scores) compared with the mean values of bone mineral density of young premenopausal women. For years, research tried to develop drugs to improve the bone mineral density. According to the compounds, antiresorptive agents are able to decrease the fracture rate by about 30% to 70%, and to increase the bone mineral density. However, the agents increasing the most bone mineral density are not necessarily those that influence the most fracture rates. It has been known for years that parathyroid hormone (PTH) administered cyclically is able to increase bone mineral density. Two analogues of PTH have been developed: PTH (1-34) and PTH (1-84). Both of them are able to increase bone mineral density and reduce the rate of vertebral fracture but not of the hip, nor of nonvertebral fractures, the latter at least for PTH (1-84). Their exact place in the armamentarium of therapy of osteoporosis and their best time of administration are not yet definitely settled. New modes of administration (transdermal, intranasal, oral) will probably become available soon. With all the drugs available today and those still in development, it can be hoped that osteoporosis will become a disease of the past.