Evaluation of bone turnover in type I osteoporosis using biochemical markers specific for both bone formation and bone resorption

Association between changes in serum bone metabolism markers and bone microarchitecture changes during basic combat training - The ARMI study

IMPORTANCE

U.S. Army Basic Combat Training (BCT) improves tibial volumetric bone mineral density (BMD) and structure in most, but not all soldiers. Few studies have investigated whether changes in serum bone biomarkers during BCT are associated with changes in tibial BMD and bone structure following BCT.

OBJECTIVE

To characterize bone biomarker changes during BCT and to investigate the relationship between changes in bone biomarkers and changes in tibial BMD and bone structure.

METHODS

We enrolled 235 trainees entering BCT in this ten-week prospective observational study. Trainees provided fasted blood samples and questionnaires weekly throughout BCT. Procollagen type 1 N-terminal propeptide (PINP) and C-terminal telopeptide of type 1 collagen (CTX) were measured by enzyme-linked immunoabsorbent assays every two weeks during BCT. We evaluated body composition and mass via dual-energy X-ray absorptiometry and bone structure, microarchitecture, and mineral density at the distal tibia via high-resolution peripheral quantitative computed tomography at baseline and post-BCT.

RESULTS

Both male (n = 110) and female trainees (n = 125) were young (20.9 ± 3.7 and 20.7 ± 4.3 years, respectively), with normal to overweight BMIs (25.2 ± 4.1 and 24.2 ± 3.6 kg/m2, respectively). In female trainees, PINP increased during and post-BCT compared to baseline, with the greatest increase in PINP at week four (45.4 % ± 49.6, p < 0.0001), whereas there were no changes in CTX. PINP also increased in male trainees, but only at weeks two and four (21.9 % ± 24.5, p = 0.0027 and 35.9 % ± 35.8, p < 0.0001, respectively). Unlike female trainees, in males, CTX was lower than baseline at weeks four, eight, and post-BCT. The change in PINP from baseline to week four of BCT was positively associated with changes in tibial BMD, Tb.BMD, Tb.Th, Tb.BV/TV, Ct.Th, Ct.Ar, and Ct.Po from the baseline to post-BCT.

CONCLUSION

The bone formation marker PINP increases during U.S. Army BCT, especially during the first four weeks. Increases in PINP, but not CTX, were correlated with improved BMD and bone structure in the distal tibia.

Impact of Long-Term Swimming Exercise on Rat Femur Bone Quality

Considering the conflicting evidence regarding the potential long-term detrimental effect of swimming during growth on femur quality and fracture risk, our aim was to investigate the effect of eight months of swimming on femur quality. Twenty male eight-week-old Wistar rats were assigned into a swimming (SW; n = 10; 2 h/day, 5 days/week) or active control group (CG; n = 10, housed with running wheel) for eight months. Plasma osteocalcin and C-terminal telopeptide of type I collagen concentrations (ELISA) were assessed at baseline, four, and eight months of protocol. Femur structure (micro-computed tomography), biomechanical properties (three-point bending), and cellular density (histology) were determined after the protocol. SW displayed a lower uncoupling index, suggesting higher bone resorption, lower empty lacunae density, cortical and trabecular femur mass, femur length and cortical thickness, and higher cortical porosity than CG (p < 0.05). Although both biomarkers' concentrations decreased in both groups throughout the experiment (p < 0.001), there were no significant differences between groups (p > 0.05). No differences were also found regarding biomechanical properties, bone marrow adiposity, and osteocyte and osteoclast densities (p > 0.05). Long-term swimming was associated with unbalanced bone turnover and compromised femur growth, lower femur mass, and deteriorated cortical bone microarchitecture. However, femur trabecular microarchitecture and biomechanical properties were not affected by swimming.

Moderate-Intensity Exercise Preserves Bone Mineral Density and Improves Femoral Trabecular Bone Microarchitecture in Middle-Aged Mice

Background

Aging leads to significant bone loss and elevated osteoporosis risk. Exercise slows age-related bone loss; however, the effects of various moderate-intensity exercise training volumes on bone metabolism remain unclear. This study aimed to determine the degree to which different volumes of moderate-intensity aerobic exercise training influence bone mineral density (BMD), bone mineral content (BMC), femoral trabecular bone microarchitecture, and cortical bone in middle-aged mice.

Methods

Twenty middle-aged male C57BL/6 mice were randomly assigned 8 weeks of either (1) non-exercise (CON); (2) moderate-intensity with high-volume exercise (EX_MHV); or (3) moderate-intensity with low-volume exercise (EX_MLV) (N=6–7, respectively). Femoral BMD and BMC were evaluated using dual energy X-ray absorptiometry, and trabecular and cortical bone were measured using micro-computed tomography.

Results

Femoral BMD in EX_MHV but not EX_MLV was significantly higher (P<0.05) than in CON. The distal femoral fractional trabecular bone volume/tissue volume (BV/TV, %) was significantly higher (P<0.05) in both EX_MHV and EX_MLV than in CON mice. Increased BV/TV was induced by significantly increased trabecular thickness (mm) and tended to be higher (P<0.10) in BV (mm³) and lower in trabecular separation (mm) in EX_MHV and EX_MLV than in CON. The femoral mid-diaphysis cortical bone was stronger in EX_MLV than EX_MHV.

Conclusions

Long-term moderate-intensity aerobic exercise with low to high volumes can be thought to have a positive effect on hindlimb BMD and attenuate age-associated trabecular bone loss in the femur. Moderate-intensity aerobic exercise may be an effective and applicable exercise regimen to prevent age-related loss of BMD and BV.

The role of sphingosine-1-phosphate in bone remodeling and osteoporosis

Osteoporosis is a systemic bone disease that affects more than 200 million people worldwide and is caused by the disruption of the equilibrium between osteoclastic bone resorption and osteoblastic bone formation. Sphingosine-1-phosphate (S1P) is a natural, bioactive sphingolipid that has been shown to play a major role in cardiovascular and immunological pathologies by regulating biological and cellular processes, including migration, differentiation, proliferation and survival. Recent studies also suggest a central role for S1P in bone diseases, including osteoporosis; however, the effects of S1P, particularly in bone metabolism, remain to be further elucidated. In this review, we summarize the available literature on the role of S1P in bone metabolism with a focus on osteoporosis. On the cellular level, S1P acts as an osteoclast-osteoblast coupling factor to promote osteoblast proliferation and bone formation. Moreover, the recruitment of osteoclast precursors to resorption sites is regulated by the interplay of S1P gradients and S1P receptor expression. From a clinical perspective, increasing evidence suggests that systemically elevated S1P blood levels may serve as an independent risk factor for osteoporosis-related fractures. Taken together, S1P signaling is a potential therapeutic target and may serve as a novel biomarker in patients with systemic bone disease.

Trabecular Bone Microarchitecture Improvement Is Associated With Skeletal Nerve Increase Following Aerobic Exercise Training in Middle-Aged Mice

Advancing age is associated with bone loss and an increased risk of osteoporosis. Exercise training improves bone metabolism and peripheral nerve regeneration, and may play a critical role in osteogenesis and increase in skeletal nerve fiber density. In this study, the potential positive role of aerobic exercise training in bone metabolism and skeletal nerve regeneration was comprehensively evaluated in 14-month-old male C57BL/6 mice. The mice were divided into two groups: no exercise (non-exercise group) and 8-weeks of aerobic exercise training (exercise group), with six mice in each group. Dual-energy X-ray absorptiometry and micro-computed tomography showed that femoral and tibial bone parameters improved after aerobic exercise training. Greater skeletal nerve fiber density was also observed in the distal femoral and proximal tibial periostea, measured and analyzed by immunofluorescence staining and confocal microscopy. Pearson correlation analysis revealed a significant association between skeletal nerve densities and trabecular bone volume/total volume ratios (distal femur; R ² = 0.82, p < 0.05, proximal tibia; R ² = 0.59, p = 0.07) in the exercise group; while in the non-exercise group no significant correlation was found (distal femur; R ² = 0.10, p = 0.54, proximal tibia; R ² = 0.12, p = 0.51). Analysis of archival microarray database confirmed that aerobic exercise training changed the microRNA profiles in the mice femora. The differentially expressed microRNAs reinforce the role of aerobic exercise training in the osteogenic and neurogenic potential of femora and tibiae. In conclusion, 8-weeks of aerobic exercise training positively regulate bone metabolism, an effect that paralleled a significant increase in skeletal nerve fiber density. These findings suggest that aerobic exercise training may have dual utility, both as a direct stimulator of bone remodeling and a positive regulator of skeletal nerve regeneration.

Decreased serum Wnt antagonist levels in patients with active acromegaly

OBJECTIVES

The Wnt signalling pathway is an important modulator of bone metabolism. This study aims to clarify the changes in Wnt antagonists in active and biochemically controlled acromegalic patients.

METHODS

We recruited 77 patients newly diagnosed with acromegaly. Of those, 41 patients with complete follow-up data were included. Thirty healthy patients matched for age, sex, and body mass index served as controls. Wnt antagonists [sclerostin (SOST), dickkopf-related protein 1 (DKK-1), and Wnt inhibitory factor 1 (WIF-1)], bone turnover markers [osteocalcin, procollagen type 1 N-terminal propeptide (P1NP), and C-terminal telopeptide of type 1 collagen (CTX)] and the bone remodelling index were investigated at baseline and posttreatment.

RESULTS

Acromegalic patients had higher serum osteocalcin, P1NP, and CTX and a higher bone remodelling index than controls (P < 0.01). Serum SOST, DKK-1 and WIF-1 levels were significantly decreased in patients compared to controls (all P < 0.01). Serum SOST and WIF-1 levels were negatively correlated with growth hormone levels; SOST levels were positively correlated with WIF-1. Posttreatment, serum bone turnover markers and the bone remodelling index decreased, while SOST and WIF-1 significantly increased (P < 0.05). DKK-1 levels did not change compared to baseline (P > 0.05). In biochemically controlled patients, SOST and WIF-1 levels and bone turnover markers were restored and did not differ from those of the control participants (all P > 0.05).

CONCLUSION

Patients with active acromegaly exhibited significantly decreased Wnt antagonist levels. The reduction in Wnt antagonists is a compensatory mechanism to counteract increased bone fragility in active acromegaly.

Altered collagen chemical compositional structure in osteopenic women with past fractures: A case-control Raman spectroscopic study

Incidences of low-trauma fractures among osteopenic women may be related to changes in bone quality. In this blinded, prospective-controlled study, compositional and heterogeneity contributors of bone quality to fracture risk were examined. We hypothesize that Raman spectroscopy can differentiate between osteopenic women with one or more fractures (cases) from women without fractures (controls). This study involved the Raman spectroscopic analysis of cortical and cancellous bone composition using iliac crest biopsies obtained from 59-cases and 59-controls, matched for age (62.0 ± 7.5 and 61.7 ± 7.3 years, respectively, p = 0.38) and hip bone mineral density (BMD, 0.827 ± 0.083 and 0.823 ± 0.072 g/cm3, respectively, p = 0.57). Based on aggregate univariate case-control and odds ratio based logistic regression analyses, we discovered two Raman ratiometric parameters that were predictive of past fracture risk. Specifically, 1244/1268 and 1044/959 cm-1 ratios, were identified as the most differential aspects of bone quality in cortical cases with odds ratios of 0.617 (0.406-0.938 95% CI, p = 0.024) and 1.656 (1.083-2.534 95% CI, p = 0.020), respectively. Both 1244/1268 and 1044/959 cm-1 ratios exhibited moderate sensitivity (59.3-64.4%) but low specificity (49.2-52.5%). These results suggest that the organization of mineralized collagen fibrils were significantly altered in cortical cases compared to controls. In contrast, compositional and heterogeneity parameters related to mineral/matrix ratios, B-type carbonate substitutions, and mineral crystallinity, were not significantly different between cases and controls. In conclusion, a key outcome of this study is the significant odds ratios obtained for two Raman parameters (1244/1268 and 1044/959 cm-1 ratios), which from a diagnostic perspective, may assist in the screening of osteopenic women with suspected low-trauma fractures. One important implication of these findings includes considering the possibility that changes in the organization of collagen compositional structure plays a far greater role in postmenopausal women with osteopenic fractures.

Effects of post exercise protein supplementation on markers of bone turnover in adolescent swimmers

BACKGROUND

This study examined the effects of whey protein supplementation, compared with an isocaloric carbohydrate beverage and water, consumed immediately following an intense swimming trial on bone turnover in adolescent swimmers.

METHODS

Fifty-eight (31 female, 27 male) swimmers (14.1 ± 0.4 years) were stratified into three groups matched for age, sex and body mass. The protein and carbohydrate groups consumed two isocaloric post-exercise beverages each containing 0.3 g.kg- 1 of whey protein (with ~ 6 mg of calcium) or maltodextrin while the control group consumed water. Participants provided a morning, fasted, resting blood sample, then performed an intense swimming trial consisting of a maximal 200 m swim followed by a high intensity interval swimming protocol (5x100m, 5x50m and 5x25m; 1:1 work-to-rest ratio). Following swimming, they consumed their first respective post-exercise beverage, and 2 h later, they performed a second maximal swim immediately followed by the second beverage. Approximately 3 h after the second beverage, two post-consumption blood samples were collected at 8 h and 24 h from baseline. Procollagen type 1 intact N-terminal propeptide (PINP) and carboxy-terminal collagen crosslinks (CTXI) were measured in serum. The multiples of medians of PINP and CTXI were also used to calculate bone turnover rate and balance.

RESULTS

No significant changes were observed in PINP. CTXI increased (+ 11%) at 8 h in all groups, but then significantly decreased (- 22%) at 24 h in the protein group only. The protein group also had a significantly higher calculated rate of bone turnover at 8 h and 24 h compared to baseline, which was not observed in the other groups.

CONCLUSIONS

These results shed light on the potential importance of protein consumed shortly after intense swimming in promoting positive bone turnover responses up to 24 h following exercise in adolescent athletes.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov PRS; NCT04114045. Registered 1 October 2019 - Retrospectively registered.

Geometric and Mechanical Bone Response to a Multidisciplinary Weight Loss Intervention in Adolescents With Obesity: The ADIBOX Study

The effectiveness of structured multidisciplinary weight loss (WL) programs combining nutrition and physical activity on bone geometry and strength remains uncertain in adolescents with obesity. The study investigated the impact of a structured WL intervention on bone geometry and strength in adolescents with obesity. Thirty-one adolescents with obesity (mean [standard deviation] 13.61 [1.27] yr, body mass index Z-score 2.26 [0.30]) experienced an 8-mo WL program. A group of 23 maturation-matched controls (mean [standard deviation] 15.90 [0.43] yr, body mass index Z-score -0.12 [0.48]) were recruited for calculating Z-scores. Body composition, bone density, geometry, and mechanical properties were assessed using dual-energy X-ray absorptiometry and dual-energy X-ray absorptiometry-derived hip structural analysis. Plasma concentration of leptin, estradiol, collagen type 1 cross-linked C-telopeptide (CTx), and procollagen type 1 N-terminal propeptide were measured. Longitudinal analysis showed that adolescents with obesity reduced body weight and fat mass (total [g, %; p < 0.007]). After 8 mo, body mineral density at total body less head (Δ 3.22 [3.58] % p < 0.001) and lumbar spine (Δ 3.67 [4.04] % p < 0.001) increased. At the narrow neck (NN) of the femur, lower body mineral density (Δ -7.19 [8.79] % p < 0.001) and higher endocortical diameter and width were observed (NN endocortical diameter Δ 2.85 [0.26] %, NN width Δ 5.48 [10.84] %, respectively). An increased buckling ratio (Δ 8.24 [2.00] % p = 0.005) was also evident. Similar concentration of procollagen type 1 N-terminal propeptide and CTx was seen from baseline to 8 mo. However, at 4 mo, lower CTx levels were observed. The 8-mo WL program was associated with some positive adaptations among bone density parameters for the whole body and spine. However, bone geometry and strength estimates appeared to weaken at the NN. Clinically, the buckling ratio score at the NN was close to the fracture threshold. An "androgynous-like" adaptation was observed with bone geometry changes demonstrating periosteal expansion and endocortical resorption.

Gonadal hormones may predict structural bone fragility in elite female soccer player

Purpose: This study determined the impact of menstrual status on bone tissue in elite post-pubertal female soccer players over an entire season.Methods: Fifty-one elite female soccer players participated. At baseline, forty-one were assigned to the low hormonal androgenic profile (low-HAPL) and 10 to the high hormonal androgenic profile (high-HAPL).Results: An 8-month training program led to increased bone mineral density content (p<0.05). The low-HAPL athletes improved the Narrow neck average cortical thickness (ACT) by 1.4% and reduced the corresponding Buckling ratio (BR) by 2.6%, thus decreasing the fracture risk (p<0.05). The high-HAPL athletes decreased the Narrow neck ACT by 5.4% and increased the BR by 2.6%, increasing fracture risk (p<0.05). Differences were assigned as being "very likely beneficial" for the low-HAPL athletes, supported by very large (d=3.41) and large (d=1.58) effect sizes for the Narrow neck ACT and BR, respectively.Conclusion: A season of soccer training has induced bone geometry improvements in adolescent females. Bone health parameters improved in the two clusters. However, high-HAPL athletes decreased its resistance to loading compare to low-HAPL athletes. Even if female players do not present clinical symptoms related to their hormonal status, sport medicine physicians should pay attention to their structural bone fragility.

The effect of bisphosphosphonates on bone turnover and bone balance in postmenopausal women with osteoporosis: The T-score bone marker approach in the TRIO study

Postmenopausal osteoporosis is characterised by increased bone turnover and an imbalance between bone resorption and formation. Bisphosphonate treatment reduces bone turnover but their effect on bone balance is yet to be fully investigated. Using the T-score approach our aims were to: i) investigate the effects of oral nitrogen-containing bisphosphonates on bone balance and turnover in postmenopausal women with osteoporosis and ii) determine the relationship of the change in bone balance and turnover with the change in BMD at the lumbar spine and total hip. Women were recruited, mean age 67 years, and randomised to receive: ibandronate (n = 55, 150 mg/month), alendronate (n = 54, 70 mg/week) or risedronate (n = 56, 35 mg/week). They also received calcium and vitamin D daily. A fasting serum sample was collected at baseline and weeks 1, 2, 4, 12, 13, 48 and 96. The control group were 226 healthy premenopausal women receiving no treatments. PINP and CTX were measured using the iSYSIDS analyser and BMD (in g/cm2) of the lumbar spine and total hip were measured by DXA (Hologic Inc). PINP and CTX values were log10-transformed and normalised. T-scores were calculated using the mean and standard deviation from the premenopausal group. Bone turnover and bone balance were calculated from the T-scores. Mean levels (95% CI) of balance and turnover are shown in the table. The change in turnover at weeks 4, 12 and 48 was inversely correlated with the change in lumbar spine and total hip BMD at weeks 48 and 96, (p < .01 to p < .001). The change in balance at week 4 positively correlated with the change in total hip BMD at weeks 48, (p < .01). Bisphosphonates resulted in an initial positive balance and a reduction in turnover. Some of these changes were associated with increases in BMD. Bone turnover is a better predictor of BMD than bone balance.

Increases in PYY and uncoupling of bone turnover are associated with loss of bone mass after gastric bypass surgery

CONTEXT

The gut hormones peptide YY (PYY) and ghrelin mediate in part the metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. However, preclinical data suggest these hormones also affect the skeleton and could contribute to postoperative bone loss.

OBJECTIVE

We investigated whether changes in fasting serum total PYY and ghrelin were associated with bone turnover marker levels and loss of bone mineral density (BMD) after RYGB.

DESIGN, SETTING, PARTICIPANTS

Prospective cohort of adults undergoing RYGB (n=44) at San Francisco academic hospitals.

MAIN OUTCOME MEASURES

We analyzed 6-month changes in PYY, ghrelin, bone turnover markers, and BMD by dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT). We calculated the uncoupling index (UI), reflecting the relative balance of bone resorption and formation.

RESULTS

Postoperatively, there was a trend for an increase in PYY (+25pg/mL, p=0.07) and a significant increase in ghrelin (+192pg/mL, p<0.01). PYY changes negatively correlated with changes in spine BMD by QCT (r=-0.36, p=0.02) and bone formation marker P1NP (r=-0.30, p=0.05). Relationships were significant after adjustments for age, sex, and weight loss. No consistent relationships were found between ghrelin and skeletal outcomes. Mean 6-month UI was -3.3; UI correlated with spine BMD loss by QCT (r=0.40, p=0.01).

CONCLUSIONS

Postoperative PYY increases were associated with attenuated increases in P1NP and greater declines in spine BMD by QCT. Uncoupling of bone turnover correlated with BMD loss. These findings suggest a role for PYY in loss of bone mass after RYGB and highlight the relationship between intestinal and skeletal metabolism.

Effect of whole soy and isoflavones daidzein on bone turnover and inflammatory markers: a 6-month double-blind, randomized controlled trial in Chinese postmenopausal women who are equol producers

BACKGROUND

Human studies have demonstrated the beneficial effects of soy or isoflavones on bone metabolism. However, conflicting data remain. Equol is the intestinal metabolite of the isoflavone daidzein. The health benefits of soy are more pronounced in equol producers than those not producing equol. This 6-month randomized controlled trial aimed to examine the effect of whole soy (soy flour) and purified daidzein on bone turnover markers (BTMs) in Chinese postmenopausal women who are equol producers.

METHODS

A total of 270 eligible women were randomized to either one of the three isocaloric supplements as follows: 40 g soy flour (whole soy group), 40 g low-fat milk powder + 63 mg daidzein (daidzein group), or 40 g low-fat milk powder (placebo group) given as a solid beverage daily for 6 months. The following fasting venous samples were collected at the baseline and end of the trial to analyze BTMs: serum cross-linked C-telopeptides of type I collagen, bone-specific alkaline phosphatase, osteocalcin, procollagen type I N-terminal propeptide, and 25(OH)D₃. Inflammation-related biomarkers, such as serum interleukin-6, tumor necrosis factor-alpha, C-reactive protein, transferrin, and homocysteine, were also tested to explore potential mechanisms.

RESULTS

A total of 253 subjects validly completed the study protocol. Urinary isoflavones suggested a good compliance to the treatments. Intention-to-treat and per-protocol analyses indicated no significant difference in the 6-month or percentage changes in the parameters of bone metabolism and inflammatory markers among the three treatment groups.

CONCLUSIONS

Whole soy and purified daidzein at provided dosages exhibited no significant effect on the bone metabolism and inflammation levels among Chinese equol-producing postmenopausal women.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01270737.

Biomarkers of Osteoporosis: An Update

Background:

Osteoporosis, characterized by compromised bone quality and strength is associated with bone fragility and fracture risk. Biomarkers are crucial for the diagnosis or prognosis of a disease as well as elucidating the mechanism of drug action and improve decision making.

Objective:

An exhaustive description of traditional markers including bone mineral density, vitamin D, alkaline phosphatase, along with potential markers such as microarchitectural determination, trabecular bone score, osteocalcin, etc. is provided in the current piece of work. This review provides insight into novel pathways such as the Wnt signaling pathway, neuro-osseous control, adipogenic hormonal imbalance, gut-bone axis, genetic markers and the role of inflammation that has been recently implicated in osteoporosis.

Methods:

We extensively reviewed articles from the following databases: PubMed, Medline and Science direct. The primary search was conducted using a combination of the following keywords: osteoporosis, bone, biomarkers, bone turnover markers, diagnosis, density, architecture, genetics, inflammation.

Conclusion:

Early diagnosis and intervention delay the development of disease and improve treatment outcome. Therefore, probing for novel biomarkers that are able to recognize people at high risk for developing osteoporosis is an effective way to improve the quality of life of patients and to understand the pathomechanism of the disease in a better way.

Rapamycin improves bone mass in high-turnover osteoporosis with iron accumulation through positive effects on osteogenesis and angiogenesis

Iron accumulation is an independent risk factor for type I osteoporosis, but the molecular mechanisms of the phenomenon are not well defined, and effective therapy has not been reported. Here, we found that the level of mTOR was increased both in wild-type mouse models with iron accumulation and transgenic mouse models (Hepc^-/-) of high-turnover osteoporosis with iron accumulation. We show that an increased level of mTOR can depress osteogenesis and angiogenesis by Cxcl9 both in bone and in vitro. Suppression of mTOR in mouse models by rapamycin and in vitro by siRNA transfection recovered both osteogenesis and angiogenesis. These findings revealed the role of mTOR in osteogenesis and angiogenesis in high-turnover osteoporosis with iron accumulation and showed that rapamycin targeting of mTOR ameliorates osteogenesis and angiogenesis to improve bone mass.

Bone turnover markers to explain changes in lumbar spine BMD with abaloparatide and teriparatide: results from ACTIVE

Early PINP changes correlate with 18-month lumbar spine BMD changes and the correlation was greater with abaloparatide versus teriparatide. The uncoupling index was similar between the two agents.

INTRODUCTION

We evaluated the relationship between early PINP changes and subsequent changes in spine BMD following abaloparatide and teriparatide treatments. We also explored the use of an "uncoupling index" (UI), the balance between bone formation and bone resorption, which we hypothesised would be similar in response to these treatment groups.

METHODS

Blood samples were taken for measurement of bone turnover markers (BTMs) s-PINP and s-CTX at baseline, 1, 3, 6, 12, and 18 months from 189 abaloparatide patients and 227 teriparatide patients randomly selected from all participants who completed the study. BMD was measured by DXA at baseline, 6, 12, and 18 months. Correlations were calculated between log ratio of BTMs from baseline to 3 months and percent change from baseline in BMD at 18 months. A UI was calculated using log transformation and subtraction of the standard deviate for s-CTX from the standard deviate for s-PINP for each patient.

RESULTS

Early BTM changes were associated with subsequent BMD changes for both treatments. Pearson correlations for the log ratio of PINP over baseline at 3 months and BMD percent change from baseline at 18 months were larger (P < 0.0001) with abaloparatide (r = 0.561) than teriparatide (r = 0.198). The mean UI at 1 month was greater for abaloparatide versus teriparatide (1.743 and 1.493, respectively; P = 0.03) but was similar at 3 months or later time points.

CONCLUSIONS

Early s-PINP changes correlate with percentage change in lumbar spine BMD 18 months after treatment with both abaloparatide and teriparatide, though the correlation with abaloparatide was greater. The UI was similar between abaloparatide and teriparatide suggesting that the balance between formation and resorption markers was similar.

The effects of short-term use of granulocyte colony-stimulating factor on bone metabolism in child cancer patients

OBJECTIVE:

The granulocyte colony-stimulating factor (G-CSF) is the most commonly used hematopoietic growth factor recombinant DNA technology. It affects bone metabolism by modulating both osteoclast and osteoblast functions. The aim of the present study was to investigate the effects of short-term use of G-CSF on bone metabolism in children with leukemia and solid tumors.

METHODS:

Thirty-six patients with a malignancy who received G-CSF therapy according to chemotherapy protocols and another 20 growth factor-free cancer patients who were enrolled as controls were included in the study. The serum osteocalcin and urinary free deoxypyridinoline levels were measured before the start of G-CSF therapy, on day 3 after treatment, and 7 days after G-CSF therapy was discontinued. In the control group, the measurements were made during corticosteroid and methotrexate-free chemotherapy.

RESULTS:

The mean osteocalcin level (8.6±2.3 ng/mL) from before the onset of treatment decreased significantly (7.7±2.3 ng/mL) on day 3 of G-CSF therapy and significantly increased after 7 days of G-CSF therapy (7.9±2.2 ng/mL) (p<0.001 and p<0.001, respectively), which was still significantly lower than the pre-G-CSF values (p<0.001). The urinary free deoxypyridinoline level significantly increased on day 3 of G-CSF treatment (25.6±6.5 nmol/mmol Cr) and significantly decreased after 7 days of G-CSF therapy (22.6±6.4 nmol/mmol Cr) (p<0.001 and p<0.001, respectively), which was still significantly higher than the values recorded before G-CSF therapy (p<0.001).

CONCLUSION:

The findings show that the short-term use of G-CSF in children with cancer can affect bone metabolism and can play a role in metabolic changes. Decreased osteoblastic activity and increased osteoclastic activity suggest that osteoporosis may be associated with bone pain in these patients.

The effects of high-dose calcitriol and individualized exercise on bone metabolism in breast cancer survivors on hormonal therapy: a phase II feasibility trial

INTRODUCTION

Cancer treatment-induced bone loss (CTIBL) is a long-term side effect of breast cancer therapy. Both calcitriol and weight-bearing exercise improve bone metabolism for osteoporotic patients, but are unproven in a breast cancer population. We used a novel high-dose calcitriol regimen with an individualized exercise intervention to improve bone metabolism in breast cancer survivors.

METHODS

We accrued 41 subjects to this open label, 2 × 2 factorial, randomized feasibility trial. Breast cancer survivors were randomized to receive the following: (1) calcitriol (45 micrograms/week), (2) individualized exercise with progressive walking and resistance training, (3) both, or (4) a daily multivitamin (control condition) for 12 weeks. Primary outcomes included changes in biomarkers of bone formation, bone resorption, and the bone remodeling index, a composite measure of bone formation and resorption. Safety measures included clinical and biochemical adverse events. A main effect analysis was used for these endpoints.

RESULTS

Hypercalcemia was limited to three grade I cases with no grade ≥ 2 cases. Among exercisers, 100% engaged in the prescribed aerobic training and 44.4% engaged in the prescribed resistance training. Calcitriol significantly improved bone formation (Cohen's d = 0.64; p < 0.01), resulting in a non-significant increase in the bone remodeling index (Cohen's d = 0.21; p = 31). Exercise failed to improve any of the bone biomarkers.

CONCLUSIONS

Both calcitriol and exercise were shown to be feasible and well tolerated. Calcitriol significantly improved bone formation, resulting in a net increase of bone metabolism. Compliance with the exercise intervention was sub-optimal, which may have led to a lack of effect of exercise on bone metabolism.

Bone turnover markers after the menopause: T-score approach

Bone turnover increases at the menopause and is associated with accelerated bone loss. However, it is not known to what extent there is an imbalance between the processes of bone resorption and bone formation, nor whether it is the rate of bone turnover or the bone balance that is most closely associated with the rate of bone loss. We studied 657 healthy women ages 20 to 79 from five European cities (the OPUS Study) and divided them into two premenopausal age groups, 20 to 29 (n=129), 30 to 39years (n=183), and three postmenopausal groups 1 to 10years (n=91), 11 to 20years (n=131) and 21+ years since menopause (n=123). We measured collagen type I C-telopeptide (CTX, a marker of bone resorption) and procollagen I N-propeptide (PINP, a marker of bone formation). We used these two markers to calculate the overall bone turnover and the difference between bone formation and resorption (bone balance) using the results from the women ages 30 to 39years to calculate a standardised score (T-score). We found that the CTX and PINP levels were higher in the women ages 20 to 29 and in the women in the three menopausal groups as compared to women ages 30 to 39years (p<0.001). For example, the CTX and PINP levels were 80 and 33% higher in women 1 to 10years since menopause as compared to women ages 30 to 39years. In this group of postmenopausal women, the bone turnover expressed as a T-score was 0.72 (0.57 to 0.88, 95%CI) and the bone balance was -0.37 (-0.59 to -0.16). There was greater rate of bone loss from the total hip in all the groups of women after the menopause compared to women before the menopause. We conclude that the bone loss after the menopause is associated with both an increase in bone turnover and a negative bone balance and that bone loss was most clearly associated with overall bone turnover.

Regulation of bone mineral density in the grey squirrel, Sciurus carolinensis: Bioavailability of calcium oxalate, and implications for bark stripping

The damage caused when grey squirrels strip the outer bark off trees and ingest the underlying phloem can result in reduced timber quality or tree death. This is extremely costly to the UK forestry industry and can alter woodland composition, hampering conservation efforts. The calcium hypothesis proposes that grey squirrels ingest phloem to ameliorate a seasonal calcium deficiency. Calcium in the phloem predominantly takes the form of calcium oxalate (CaOx), however not all mammals can utilise CaOx as a source of calcium. Here, we present the results of a small-scale study to determine the extent to which grey squirrels can utilise CaOx. One of three custom-made diets containing calcium in varying forms and quantities (CaOx diet, Low-calcium carbonate (CaCO3 ) diet and Control diet) were fed to three treatment groups of six squirrels for 8 weeks. Bone densitometric properties were measured at the end of this time using peripheral quantitative computed tomography and micro-computed tomography. Pyridinoline-a serum marker of bone resorption-was measured regularly throughout the study. Bone mineral density and cortical mineralisation were lower in squirrels fed the CaOx diet compared to the Control group but similar to that of those on the Low-calcium diet, suggesting that calcium from calcium oxalate was not effectively utilised to maintain bone mineralisation. Whilst no differences were observed in serum pyridinoline levels between individuals on different diets, females had on average higher levels than males throughout the study. Future work should seek to determine if this apparent lack of ability to utilise CaOx is common to a large sample of grey squirrels and if so, whether it is consistent across all areas and seasons.

Physical activity for women with breast cancer after adjuvant therapy

BACKGROUND

Women with a diagnosis of breast cancer may experience short- and long-term disease and treatment-related adverse physiological and psychosocial outcomes. These outcomes can negatively impact prognosis, health-related quality of life (HRQoL), and psychosocial and physical function. Physical activity may help to improve prognosis and may alleviate the adverse effects of adjuvant therapy.

OBJECTIVES

To assess effects of physical activity interventions after adjuvant therapy for women with breast cancer.

SEARCH METHODS

We searched the Cochrane Breast Cancer Group (CBCG) Specialised Registry, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Physiotherapy Evidence Database (PEDro), SPORTDiscus, PsycINFO, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform, on 18 September 2015. We also searched OpenGrey and Healthcare Management Information Consortium databases.

SELECTION CRITERIA

We searched for randomised and quasi-randomised trials comparing physical activity interventions versus control (e.g. usual or standard care, no physical activity, no exercise, attention control, placebo) after adjuvant therapy (i.e. after completion of chemotherapy and/or radiation therapy, but not hormone therapy) in women with breast cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, and extracted data. We contacted trial authors to ask for additional information when needed. We calculated an overall effect size with 95% confidence intervals (CIs) for each outcome and used GRADE to assess the quality of evidence for the most important outcomes.

MAIN RESULTS

We included 63 trials that randomised 5761 women to a physical activity intervention (n = 3239) or to a control (n = 2524). The duration of interventions ranged from 4 to 24 months, with most lasting 8 or 12 weeks (37 studies). Twenty-eight studies included aerobic exercise only, 21 involved aerobic exercise and resistance training, and seven used resistance training only. Thirty studies described the comparison group as usual or standard care, no intervention, or control. One-fifth of studies reported at least 20% intervention attrition and the average physical activity adherence was approximately 77%.No data were available on effects of physical activity on breast cancer-related and all-cause mortality, or on breast cancer recurrence. Analysis of immediately postintervention follow-up values and change from baseline to end of intervention scores revealed that physical activity interventions resulted in significant small-to-moderate improvements in HRQoL (standardised mean difference (SMD) 0.39, 95% CI 0.21 to 0.57, 22 studies, 1996 women; SMD 0.78, 95% CI 0.39 to 1.17, 14 studies, 1459 women, respectively; low-quality evidence), emotional function (SMD 0.21, 95% CI 0.10 to 0.32, 26 studies, 2102 women, moderate-quality evidence; SMD 0.31, 95% CI 0.09 to 0.53, 15 studies, 1579 women, respectively; low-quality evidence), perceived physical function (SMD 0.33, 95% CI 0.18 to 0.49, 25 studies, 2129 women; SMD 0.60, 95% CI 0.23 to 0.97, 13 studies, 1433 women, respectively; moderate-quality evidence), anxiety (SMD -0.57, 95% CI -0.95 to -0.19, 7 studies, 326 women; SMD -0.37, 95% CI -0.63 to -0.12, 4 studies, 235 women, respectively; low-quality evidence), and cardiorespiratory fitness (SMD 0.44, 95% CI 0.30 to 0.58, 23 studies, 1265 women, moderate-quality evidence; SMD 0.83, 95% CI 0.40 to 1.27, 9 studies, 863 women, respectively; very low-quality evidence).Investigators reported few minor adverse events.Small improvements in physical activity interventions were sustained for three months or longer postintervention in fatigue (SMD -0.43, 95% CI -0.60 to -0.26; SMD -0.47, 95% CI -0.84 to -0.11, respectively), cardiorespiratory fitness (SMD 0.36, 95% CI 0.03 to 0.69; SMD 0.42, 95% CI 0.05 to 0.79, respectively), and self-reported physical activity (SMD 0.44, 95% CI 0.17 to 0.72; SMD 0.51, 95% CI 0.08 to 0.93, respectively) for both follow-up values and change from baseline scores.However, evidence of heterogeneity across trials was due to variation in intervention components (i.e. mode, frequency, intensity, duration of intervention and sessions) and measures used to assess outcomes. All trials reviewed were at high risk of performance bias, and most were also at high risk of detection, attrition, and selection bias. In light of the aforementioned issues, we determined that the evidence was of very low, low, or moderate quality.

AUTHORS' CONCLUSIONS

No conclusions regarding breast cancer-related and all-cause mortality or breast cancer recurrence were possible. However, physical activity interventions may have small-to-moderate beneficial effects on HRQoL, and on emotional or perceived physical and social function, anxiety, cardiorespiratory fitness, and self-reported and objectively measured physical activity. The positive results reported in the current review must be interpreted cautiously owing to very low-to-moderate quality of evidence, heterogeneity of interventions and outcome measures, imprecision of some estimates, and risk of bias in many trials. Future studies with low risk of bias are required to determine the optimal combination of physical activity modes, frequencies, intensities, and durations needed to improve specific outcomes among women who have undergone adjuvant therapy.

Suppressive Effect of the n-Hexane Extract of Litsea japonica Fruit Flesh on Monosodium-Iodoacetate-Induced Osteoarthritis in Rats

We examined the antiosteoarthritic effect of the n-hexane extract of Litsea japonica fruit flesh (LJF-HE) in a rat model of monosodium-iodoacetate- (MIA-) induced osteoarthritis. LJF-HE significantly reduced the difference in weight-bearing capabilities of the hind paws between healthy and MIA-treated rats. Histological examination of the knee joints indicated that LJF-HE suppressed cartilage and bone destruction. Additionally, there were decreases in the expression of matrix metalloproteinase-2 and metalloproteinase-9 and cyclooxygenase-2 in the joints. The serum levels of deoxypyridinoline (DPD) and osteocalcin, which are markers of bone metabolism, also decreased. Furthermore, LJF-HE significantly suppressed infiltration of inflammatory cells into the synovium and inhibited the expression of proinflammatory cytokines such as tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1, and IL-6 in the joints and serum. The serum levels of leukotriene B4 and lipoxygenase were also significantly lowered by LJF-HE. Finally, LJF-HE inhibited the production of nitric oxide, prostaglandin E2, IL-6, and TNF-α in lipopolysaccharide-activated macrophages, which might be associated with inhibited phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. Our data suggest that LJF-HE has an anti-inflammatory effect and may have potential as an antiosteoarthritic agent.

Serum Osteocalcin and Testosterone Concentrations in Adult Males with or without Primary Osteoporosis: A Meta-Analysis

Osteocalcin (Ocn) and testosterone play important roles in male skeleton. However, the concentrations of serum osteocalcin and testosterone have never been systematically compared between populations with and without primary male osteoporosis, a common skeletal disorder in adult males. We searched the PubMed, Embase, and Cochrane Library for relevant studies. A meta-analysis was performed to compare the serum osteocalcin and testosterone concentrations between primary osteoporotic males and age-matched nonosteoporotic (non-OP) males. Five case-control studies with 300 adult males were included. We found no significant difference between cases and controls in serum total osteocalcin (TOcn) [95% confidence interval (CI): −1.25, 1.31; p = 0.96] and total testosterone (TT) concentrations [95% CI: −0.88, 4.22; p = 0.20]. The level of evidence of this carefully performed meta-analysis is 3a according to Oxford (UK) CEBM Levels of Evidence. Future well-designed studies with larger sample size and better standardization of Ocn assay are awaited to confirm and update our current findings.

Bone Mineral Density Response from Teriparatide in Patients with Osteoporosis

BACKGROUND

A review of data from large clinical trials reported more than 90% of subjects significantly improved their bone mineral density (BMD) at the lumbar spine (LS) with teriparatide (TPTD) (bone 39:1268-1275, 1). However, our clinical experience suggests that many patients may be non-responders, raising questions as to the true efficacy of TPTD in improving BMD in osteoporotic patients.

QUESTIONS/PURPOSES

The purpose of the study is to determine the rate of improvement in BMD following 18-24 months of teriparatide (TPTD) in patients with osteoporosis within an orthopedic hospital setting.

METHODS

This is a retrospective chart review of patients with osteoporosis who completed 18-24 months of TPTD therapy. The primary endpoint was the change in BMD at lumbar spine (LS) and hip-femoral neck (FN) and total hip (TH) following treatment. Secondary endpoints included the effect of prior bisphosphonate therapy, age, body mass index (BMI) and family history of fracture on BMD response, and the changes in bone-specific markers during active treatment.

RESULTS

Seventy-eight women and men with mean T-scores at the LS = -2.63 met the inclusion criteria. The overall group showed a 10.7% increase in LS-BMD after 24 months of TPTD. Eighty-three percent were considered responders defined as ≥3.0% increase in LS-BMD. Non-responders (16.7%) had mean LS-BMD change = -1.41%. No difference in baseline vitamin D, calcium, creatinine, BMI, age, gender, prior fracture history, or bisphosphonate use was observed between responders and non-responders. No consistent pattern of change in measures of bone markers was noted between responders and non-responders.

CONCLUSION

Eighty-three percent of patients with osteoporosis showed a >3% increase in BMD after TPTD treatment. Baseline parameters, prior bisphosphonate therapy, and the changes in bone markers showed no correlation with final BMD outcome.

Bone Turnover Markers: Use in Fracture Prediction

Bone turnover markers (BTMs) provide us with a noninvasive approach to studying bone turnover and they can be measured easily and with good precision, especially using automated analyzers. BTMs increase at menopause, and these higher levels are associated with more rapid bone loss. In some but not all studies, they are also associated with greater risk of fracture. However, the evidence base for use as predictors of fracture is not robust, and so BTMs have not been included in fracture prediction models. Further research is needed, and this might include (1) use of reference analytes such as C-telopeptide of type I collagen and procollagen I N-propeptide, measured using automated analyzers in subjects in the fasting state on more than 1 occasion; (2) careful collection of vertebral fractures, which would be the primary endpoint; and (3) common approach to statistical analyses with results expressed as hazard ratio per standard deviation of increase in BTM. We believe that by improving our approach to studying the relationship between BTMs and fracture risk, any association will become clearer and that in the future we might then be able to include BTMs in our fracture prediction models.

Biological effect of hydrolyzed collagen on bone metabolism

Osteoporosis is a chronic and asymptomatic disease characterized by low bone mass and skeletal microarchitectural deterioration, increased risk of fracture, and associated comorbidities most prevalent in the elderly. Due to an increasingly aging population, osteoporosis has become a major health issue requiring innovative disease management. Proteins are important for bone by providing building blocks and by exerting specific regulatory function. This is why adequate protein intake plays a considerable role in both bone development and bone maintenance. More specifically, since an increase in the overall metabolism of collagen can lead to severe dysfunctions and a more fragile bone matrix and because orally administered collagen can be digested in the gut, cross the intestinal barrier, enter the circulation, and become available for metabolic processes in the target tissues, one may speculate that a collagen-enriched diet provides benefits for the skeleton. Collagen-derived products such as gelatin or hydrolyzed collagen (HC) are well acknowledged for their safety from a nutritional point of view; however, what is their impact on bone biology? In this manuscript, we critically review the evidence from literature for an effect of HC on bone tissues in order to determine whether HC may represent a relevant alternative in the design of future nutritional approaches to manage osteoporosis prevention.

A Study to Assess the Validity of Estimation of Serum Ostase Level in Hyperthyroid and Hypothyroid Cases

INTRODUCTION

One of the more specific assessments of the metabolic status of bone in normal and in disease conditions is the measurement of bone specific alkaline phosphatase or ostase. The measurement of serum ostase has several advantages over the measurements of other bone parameter. Because of its relatively long half-life, in-vivo (1 to 3days), it is relatively unaffected by diurnal variation.

AIM

To find the correlation of serum ostase level in hyper and hypothyroid cases and also to study the validity of routine estimation of serum ostase in hyper and hypothyroid cases so as to monitor the base level bone health on presentation.

MATERIALS AND METHODS

Serum ostase level was studied in 74 patients with disorder of thyroid function. Serum ostase level, Thyroid Stimulating Hormone (TSH), FT3, FT4 levels were estimated by chemiluminescent technique. The instrument used was Beckman- coulter Access 2. A total of 39 patients were hypothyroid, 31 were hyperthyroid and 4 patients had subclinical hyperthyroidism.

RESULTS

The serum ostase level was found to be elevated above 40 μg/L in 26 of the cases and above 16 μg/L but below 40μg/L in 5 cases of hyperthyroidism along with decrease in Bone Mineral Density (BMD). Serum ostase level was found to be directly proportional to the serum FT3 level (Normal range of serum ostase is 8-16 μg/L).

CONCLUSION

From this study, an inference can be drawn that a routine estimation of serum ostase level in hyperthyroid cases will help in proper monitoring of decrease bone turnover as indicated by increase serum ostase level. Besides, the estimation of serum ostase level in hyperthyroid cases it is found to be valid in this study, which can turn to be an important guiding parameter to the treating physician to formulate necessary protocols and guidelines for prophylaxis, treatment and to monitor the response to therapy in cases of reduced bone turnover related to hyperthyroid state.

Biochemical Markers of Bone Turnover and Fracture Prediction

Low bone mineral density is a strong risk factor for fractures in the older woman. Biochemical markers of bone turnover may predict fracture risk independently of bone mineral density. High levels of bone resorption markers are associated with increased risk of fracture in both retrospective and prospective studies, although the evidence for bone formation markers and fracture risk is equivocal. For example, the risk of fracture is increased up to two-fold in women with elevated levels of several markers of bone resorption. Prediction models have been developed to predict the 10–year risk of fracture using bone mineral density and biochemical markers of bone turnover and these could prove very useful in clinical practice.

Procollagen markers in microdialysate can predict patient outcome after Achilles tendon rupture

Objective

Patients who sustain acute Achilles tendon rupture (ATR) exhibit variable and mostly impaired long-term functional, and patient-reported outcomes. However, there exists a lack of early predictive markers of long-term outcomes to facilitate the development of improved treatment methods. The aim of this study was to assess markers of tendon callus production in patients with ATR in terms of outcome, pain, and fatigue.

Study design and setting

Prospective cohort study; level of evidence 2. Outpatient orthopaedic/sports medicine department.

Patients

A total of 65 patients (57 men, 8 women; mean age 41±7 years) with ATR were prospectively assessed.

Assessments

Markers of tendon callus production, procollagen type I N-terminal propeptide (PINP) and procollagen type III N-terminal propeptide (PIIINP), were assessed 2 weeks postoperatively using microdialysis followed by enzymatic quantification. Normalised procollagen levels (n-PINP and n-PIIINP) were calculated as the ratio of procollagen to total protein content. Pain and fatigue were assessed at 1 year using reliable questionnaires Achilles tendon Total Rupture Score (ATRS).

Results

Patients exhibited fatigue (77.6%) and pain (44.1%) to some extent. Higher levels of n-PINP (R=0.38, p=0.016) and n-PIIINP (R=0.33, p=0.046) were significantly associated with less pain in the limb. Increased concentrations of PINP (R=−0.47, p=0.002) and PIIINP (R=−0.37, p=0.024) were related to more self-reported fatigue in the leg. The results were corroborated by multiple linear regression analyses.

Conclusions

Assessment of procollagen markers in early tendon healing can predict long-term patient-reported outcomes after ATR. These novel findings suggest that procollagen markers could be used to facilitate the development of improved treatment methods in patients who sustain ATR.

Trial registration numbers

NCT01317160: Results. NCT02318472: Pre-results.

Tolvaptan and Neurocognitive Function in Mild to Moderate Chronic Hyponatremia: A Randomized Trial (INSIGHT)

BACKGROUND

This trial assessed the effect of tolvaptan on cognition, gait, and postural stability in adult patients with mild to moderate asymptomatic hyponatremia.

STUDY DESIGN

Phase 3b, multicenter, randomized, double-blind, placebo-controlled, parallel-group pilot study.

SETTING & PARTICIPANTS

57 men and women 50 years or older with chronic asymptomatic euvolemic or hypervolemic hyponatremia (serum sodium concentration >120-<135 mEq/L) at 16 sites.

INTERVENTION

Patients were randomly assigned 1:1 to receive tolvaptan or matching placebo beginning at a dose of 15mg/d, with titration to 30 or 60mg/d based on change in serum sodium concentration and tolerance.

OUTCOMES

Primary: change from baseline in the neurocognitive composite score of speed domains. Secondary: changes from baseline in individual neurocognitive domain scores, overall neurocognitive composite score, gait and postural stability test results, and serum sodium concentrations.

RESULTS

Mean serum sodium concentration increased from 129 to 136 mEq/L in the tolvaptan group and from 130 to 132 mEq/L in the placebo group (P<0.001). There was no difference in overall neurocognitive composite scores of speed domains between groups, except for the psychomotor speed domain, which was statistically improved following hyponatremia correction with tolvaptan (treatment effect, 0.27; 95% CI, 0.04-0.51; P=0.03).

LIMITATIONS

There were some imbalances between treatment groups in baseline neurocognitive function scores and some baseline test results were near normal, leaving little opportunity for improvement. Formal sample size calculations were not performed because this was a pilot study. The study population was small (n=57) and treatment was of short duration (3 weeks). The primary end point of the study was not significant; thus, subgroup analyses are subject to errors of multiplicity and should be regarded as hypothesis generating.

CONCLUSIONS

Tolvaptan was effective in reversing chronic hyponatremia, and this correlated with improvements in results of a variety of neurocognition tests, particularly rapid motor movements, which tended to reverse following return to a low baseline serum sodium concentration after treatment withdrawal.

Evaluation of Salivary Levels of Pyridinoline Cross Linked Carboxyterminal Telopeptide of Type I Collagen (ICTP) in Periodontal Health and Disease

BACKGROUND

Traditional parameters (Pocket depth, bleeding on probing, clinical attachment loss, radiographic findings) have been used for a long time for the assessment of periodontal disease conditions. However, these parameters only indicate towards the periodontal damage that has already taken place but do not give any idea regarding the current status of the periodontal health or disease. Hence, the present study is aimed at evaluating the concentration of the bone biomarker ICTP in saliva, which can give a better real time assessment of periodontal health and disease.

MATERIALS AND METHODS

Forty three patients were selected and divided into three groups based on the recorded clinical parameters of probing pocket depth, attachment loss and bleeding on probing. Group I (Healthy, n = 11), Group II (Gingivitis, n = 17), Group III (Periodontitis. n = 15). Salivary samples were collected before scaling and root planning to avoid contamination by blood. ICTP levels were evaluated in the salivary samples by using enzyme linked immunosorbent assay (ELISA).

STATISTICAL ANALYSIS USED

Kruskal Wallis test was used to compare the mean ICTP level of the three groups.

RESULTS

ICTP was detected in all the samples. Highest mean ICTP concentrations in saliva were obtained for group III (periodontitis group) and the lowest mean ICTP concentrations were seen in group I (healthy group). This suggests that the level of ICTP in saliva increases proportionally from periodontal health to diseased conditions (gingivitis & periodontitis).

CONCLUSION

There is a substantial increase in the salivary concentration of ICTP in chronic periodontitis patients than in gingivitis and healthy patients. Salivary ICTP levels were the maximum in chronic periodontitis patients followed by gingivitis patients and the least in healthy individuals. ICTP may be considered as a biomarker in periodontal disease progression.

Comparison of antiresorptive effect of hormone therapy and ibandronate in postmenopausal osteoporotic women by assessing type I collagen C-telopeptide levels

OBJECTIVES

The aim of this study is to compare the antiresorptive effect of hormone therapy and oral ibandronate in postmenopausal osteoporotic women by measuring bone mineral density (BMD) and degradation products of C-terminal telopeptide of type I collagen (CTX) using serum crosslaps ELISA.

STUDY DESIGN

The study is a randomized comparative trial.

METHODS

About 60 women with age > 40 years, having either surgical or medical menopause with T- or Z-score below -2.5 SD were included in the study. They were randomized into two groups of 30 each; one group received conventional hormone therapy (group I) and the other group received ibandronate monthly (group II). The treatment was given for 6 months.

RESULTS

The BMD increased from 0.894 g/cm(2) to 0.933 g/cm(2) (p < 0.01) in group I and from 0.865 g/cm(2) to 0.934 g/cm(2) (p < 0.01) in group II. The increase in BMD in group I (4.3%) was less than group II (7.9%) which was significant (p < 0.01). The serum CTX levels also showed significant reduction in both groups after 6 months of therapy; more reduction was seen in group II as compared to group I (41.5% vs. 4.6%, p < 0.01).

CONCLUSION

Ibandronate can be used as a substitute to hormone therapy in women presenting with osteoporosis. Long-term studies are needed to authenticate the observation.

Bone density, microstructure and strength in obese and normal weight men and women in younger and older adulthood

Obesity is associated with greater areal BMD (aBMD) and is considered protective against hip and vertebral fracture. Despite this, there is a higher prevalence of lower leg and proximal humerus fracture in obesity. We aimed to determine if there are site-specific differences in BMD, bone structure, or bone strength between obese and normal-weight adults. We studied 100 individually-matched pairs of normal (body mass index [BMI] 18.5 to 24.9 kg/m2) and obese (BMI >30 kg/m2) men and women, aged 25 to 40 years or 55 to 75 years. We assessed aBMD at the whole body (WB), hip (TH), and lumbar spine (LS) with dual-energy X-ray absorptiometry (DXA), LS trabecular volumetric BMD (Tb.vBMD) by quantitative computed tomography (QCT), and vBMD and microarchitecture and strength at the distal radius and tibia with high-resolution peripheral QCT (HR-pQCT) and micro-finite element analysis. Serum type 1 procollagen N-terminal peptide (P1NP) and collagen type 1 C-telopeptide (CTX) were measured by automated electrochemiluminescent immunoassay (ECLIA). Obese adults had greater WB, LS, and TH aBMD than normal adults. The effect of obesity on LS and WB aBMD was greater in older than younger adults (p < 0.01). Obese adults had greater vBMD than normal adults at the tibia (p < 0.001 both ages) and radius (p < 0.001 older group), thicker cortices, higher cortical BMD and tissue mineral density, lower cortical porosity, higher trabecular BMD, and higher trabecular number than normal adults. There was no difference in bone size between obese and normal adults. Obese adults had greater estimated failure load at the radius (p < 0.05) and tibia (p < 0.01). Differences in HR-pQCT measurements between obese and normal adults were seen more consistently in the older than the younger group. Bone turnover markers were lower in obese than in normal adults. Greater BMD in obesity is not an artifact of DXA measurement. Obese adults have higher BMD, thicker and denser cortices, and higher trabecular number than normal adults. Greater differences between obese and normal adults in the older group suggest that obesity may protect against age-related bone loss and may increase peak bone mass.

Co-administration of antiresorptive and anabolic agents: a missed opportunity

Co-administration of antiresorptive and anabolic therapies has appeal because these treatments target the two main abnormalities in bone remodeling responsible for bone loss and microstructural deterioration. Antiresorptives reduce the number of basic multicellular units (BMUs) remodeling bone and reduce the volume of bone each BMU resorbs. Intermittent parathyroid hormone (PTH) increases the volume of bone formed by existing BMUs and those generated by PTH administration. PTH also increases bone formation by stimulating the differentiation, maturation, and longevity of osteoblast lineage cells residing upon quiescent bone surfaces. Despite these rationally targeted actions, enthusiasm for this approach waned when combined therapy blunted the increase in areal bone mineral density (aBMD) relative to that produced by PTH. Although many studies have since reported additive effects of combined therapy, whatever the aBMD result (blunting, additive, or null), these outcomes give little, if any, insight into changes in bone's material composition or microstructure and give misleading information concerning the net effects on bone strength. Combined therapy remains a potentially valuable approach to therapy. Because studies of antifracture efficacy comparing combined with single therapy are unlikely to be performed in humans, efforts should be directed toward improving methods of quantifying the net effects of combined therapy on bone's material composition, microarchitecture, and strength.

Suppressed bone turnover in obesity: a link to energy metabolism? A case-control study

CONTEXT

Observations in rodents suggest that osteocalcin (OC) participates in glucose metabolism. Based on human studies, it remains unclear whether circulating OC is simply a bone turnover marker (BTM) or also a mediator in interactions between the skeleton and glucose homeostasis.

OBJECTIVE

The objective of the study was to determine the responses of BTMs, including OC, to oral glucose tolerance test (OGTT) in a case-control setting.

DESIGN AND PATIENTS

Thirty-four normoglycemic young adults [mean age 19 y (SD 2.3)] with severe childhood-onset obesity and their gender- and age-matched nonobese controls underwent a standard 2-hour OGTT.

MAIN OUTCOME MEASURES

Glucose, insulin, and six BTMs including total and carboxylated OC (cOC) were determined at baseline and at 30, 60, 90, and 120 minutes during OGTT.

RESULTS

The obese and control subjects were similar in height; the mean body mass indices were 40.4 and 21.9 kg/m(2), respectively. The homeostasis model assessment index was 2.7 times greater in the obese subjects. All BTMs, except bone-specific alkaline phophatase, were lower in the obese subjects compared with the controls: the differences at baseline were 40%, 35%, 17%, 31%, and 32% for N-terminal propeptides of type I collagen, cross-linked telopeptides of type I collagen, tartrate-resistant acid phosphatase, total OC, and carboxylated OC (P < .05 for all) after adjusting for whole-body bone area. All BTMs decreased during OGTT. The relative values for the OGTT responses for total, but not for cOC (measured as area under the curve) differed between the two groups (P = .029 and P = .139, respectively): the decrease in total OC during the OGTT was less pronounced in the obese subjects. Responses in other BTMs were similar between the groups. No associations were observed between glucose metabolism and OCs during OGTT with linear regression.

CONCLUSIONS

Bone turnover markers were substantially lower in obese subjects compared with controls. Total OC and cOC showed less pronounced decrease during the OGTT in obese subjects compared with controls, whereas other BTMs responded similarly in the two groups. The role of OC, if anything, in glucose homeostasis is indirect and may be mediated via other factors than glucose or insulin.

Supplementation with calcium and short-chain fructo-oligosaccharides affects markers of bone turnover but not bone mineral density in postmenopausal women

This 24-mo randomized, double-blind, controlled trial aimed to examine whether supplementation with a natural marine-derived multi-mineral supplement rich in calcium (Ca) taken alone and in conjunction with short-chain fructo-oligosaccharide (scFOSs) has a beneficial effect on bone mineral density (BMD) and bone turnover markers (BTMs) in postmenopausal women. A total of 300 non-osteoporotic postmenopausal women were randomly assigned to daily supplements of 800 mg of Ca, 800 mg of Ca with 3.6 g of scFOS (CaFOS), or 9 g of maltodextrin. BMD was measured before and after intervention along with BTMs, which were also measured at 12 mo. Intention-to-treat ANCOVA identified that the change in BMD in the Ca and CaFOS groups did not differ from that in the maltodextrin group. Secondary analysis of changes to BTMs over time identified a greater decline in osteocalcin and C-telopeptide of type I collagen (CTX) in the Ca group compared with the maltodextrin group at 12 mo. A greater decline in CTX was observed at 12 mo and a greater decline in osteocalcin was observed at 24 mo in the CaFOS group compared with the maltodextrin group. In exploratory subanalyses of each treatment group against the maltodextrin group, women classified with osteopenia and taking CaFOS had a smaller decline in total-body (P = 0.03) and spinal (P = 0.03) BMD compared with the maltodextrin group, although this effect was restricted to those with higher total-body and mean spinal BMD at baseline, respectively. Although the change in BMD observed did not differ between the groups, the greater decline in BTMs in the Ca and CaFOS groups compared with the maltodextrin group suggests a more favorable bone health profile after supplementation with Ca and CaFOS. Supplementation with CaFOS slowed the rate of total-body and spinal bone loss in postmenopausal women with osteopenia-an effect that warrants additional investigation. This trial was registered at www.controlled-trials.com as ISRCTN63118444.

Low-dose hydrocortisone replacement therapy is associated with improved bone remodelling balance in hypopituitary male patients

OBJECTIVE

Glucocorticoid (GC) therapy is associated with adverse effects on bone metabolism, yet the effects of different GC physiological replacement regimens in hypopituitarism are not well characterised. We aimed to assess the effect of three hydrocortisone (HC) replacement dose regimens on bone turnover.

STUDY DESIGN

An open cross-over study randomising ten hypopituitary men with severe acth deficiency to three commonly used HC dose regimens: dose A (20 mg mane and 10 mg tarde), dose B (10 mg mane and 10 mg tarde) and dose C (10 mg mane and 5 mg tarde).

METHODS

Following 6 weeks of each regimen, the participants underwent 24-h serum cortisol sampling and measurement of bone turnover markers: bone-specific alkaline phosphatase, procollagen type I N-propeptide (PINP), intact osteocalcin (OC(1-49)), C-terminal cross-linking telopeptide (CTX-I) and tartrate-resistant acid phosphatase 5b (TRACP5b). Bone remodelling balance was estimated as an absolute ratio (PINP:CTX-I) and as an index using standardised scores derived from the matched controls.

RESULTS

There were significant increases in the concentrations of the formation markers PINP (P=0.045) and OC(1-49) (P=0.006) and in the PINP:CTX-I ratio (P=0.015), and a more positive bone remodelling balance index (P=0.03) was observed in patients on the lowest dose C than in those on the highest dose A. Mean 24-h cortisol concentrations correlated negatively with CTX-I (r=-0.66 and P=0.04) and TRACP5b (r=-0.74 and P=0.01) in patients on dose B and with OC(1-49) (r=-0.66 and P=0.04) and CTX-I (r=-0.81 and P<0.01) in patients on dose C. In patients receiving the lower-dose regimen, trough cortisol concentrations correlated with increased bone formation and resorption.

CONCLUSION

Low-dose HC replacement (10 mg mane and 5 mg tarde) is associated with increased bone formation and a positive bone remodelling balance. This may have a long-term beneficial effect on bone health.

Impact of an obesogenic diet program on bone densitometry, micro architecture and metabolism in male rat

BACKGROUND

The relationships between fat mass and bone tissue are complex and not fully elucidated. A high-fat/high-sucrose diet has been shown to induce harmful effects on bone micro architecture and bone biomechanics of rat. When such diet leads to obesity, it may induce an improvement of biomechanical bone parameters in rodent.Here, we examined the impact of a high-fat/high-sucrose diet on the body composition and its resulting effects on bone density and structure in male rats. Forty three Wistar rats aged 7 months were split into 3 groups: 1 sacrificed before diet (BD, n = 14); 1 subjected to 16 weeks of high-fat/high-sucrose diet (HF/HS, n = 14); 1 subjected to standard diet (Control, n = 15). Abdominal circumference and insulin sensitivity were measured and visceral fat mass was weighed. The bone mineral density (BMD) was analyzed at the whole body and tibia by densitometry. Microcomputed tomography and histomorphometric analysis were performed at L2 vertebrae and tibia to study the trabecular and cortical bone structures and the bone cell activities. Osteocalcin and CTX levels were performed to assess the relative balance of the bone formation and resorption. Differences between groups have been tested with an ANOVA with subsequent Scheffe post-hoc test. An ANCOVA with global mass and global fat as covariates was used to determine the potential implication of the resulting mechanical loading on bone.

RESULTS

The HF/HS group had higher body mass, fat masses and abdominal circumference and developed an impaired glucose tolerance (p < 0.001). Whole body bone mass (p < 0.001) and BMD (p < 0.05) were higher in HF/HS group vs. Control group. The trabecular thickness at vertebrae and the cortical porosity of tibia were improved (p < 0.05) in HF/HS group. Bone formation was predominant in HF/HS group while an unbalance bone favoring bone resorption was observed in the controls. The HF/HS and Control groups had higher total and abdominal fat masses and altered bone parameters vs. BD group.

CONCLUSIONS

The HF/HS diet had induced obesity and impaired glucose tolerance. These changes resulted in an improvement of quantitative, qualitative and metabolic bone parameters. The fat mass increase partly explained these observations.

Long-term treatment with raloxifene, but not bisphosphonates, reduces circulating sclerostin levels in postmenopausal women

We determined whether suppression of sclerostin levels by estrogen treatment was mediated by anti-resorptive effect. Raloxifene, but not bisphosphonates, suppressed circulating sclerostin concentration, suggesting that sclerostin may mediate the action of estrogen on bone metabolism, independently of their anti-resorptive effects.

INTRODUCTION

Circulating sclerostin concentrations are higher in postmenopausal than in premenopausal women, and estrogen treatment suppresses sclerostin levels in both men and women. We determined whether anti-resorptives may suppress the circulating sclerostin levels.

METHODS

We conducted a retrospective observational study. Eighty postmenopausal women were treated with raloxifene for 19.4 ± 7.7 months (n = 16), bisphosphonates for 19.2 ± 6.7 months (n = 32), or were untreated (n = 32) for 17.1 ± 4.6 months. Plasma sclerostin concentrations were measured before and after treatment.

RESULTS

Plasma sclerostin levels after treatment were significantly lower in the raloxifene than in the control group (55.8 ± 23.4 pmol/l vs. 92.1 ± 50.4 pmol/l, p = 0.046), but were similar between the bisphosphonate and control groups. Relative to baseline, raloxifene treatment markedly reduced plasma sclerostin concentration (-40.7 ± 22.8%, p < 0.001), with respect to both control (-7.5 ± 29.1%) and bisphosphonate (-3.1 ± 35.2%) groups. Changes in bone-specific alkaline phosphatase and osteocalcin levels showed reverse associations with sclerostin concentration changes in the raloxifene (γ = -0.505, p = 0.017) and control (γ = -0.410, p = 0.020) groups.

CONCLUSIONS

Raloxifene, but not bisphosphonates, significantly suppressed circulating sclerostin concentration, suggesting that sclerostin may mediate the action of estrogen on bone metabolism, independently of their anti-resorptive effects.

Effect of antiresorptive therapy on urinary hydroxyproline in postmenopausal osteoporosis

Osteoporosis becomes a serious health threat for older postmenopausal women by predisposing them to an increased risk of fracture. Osteoporosis and associated fractures are an important cause of morbidity and mortality. Special attention is being paid to early detection, management, and treatment of postmenopausal osteoporosis in women. Biochemical markers can enable dynamic and rapid measurement of total body skeletal metabolism and will be clinically useful in the management of postmenopausal osteoporosis women (PMO) and also for assessing the effects of antiresorptive therapy. With this view, we planned to assess osteoclastic activity by determining urinary hydroxyproline in osteoporotic women. The aim of this study is to measure urinary hydroxyproline (expressed as mg of hydroxyproline/g of creatinine) and serum ascorbic acid in postmenopausal women with osteoporosis and without osteoporosis. These biochemical parameters were determined 3 months post antiresorptive therapy (alendronate + calcium + vitamin D) in postmenopausal osteoporosis patients. 60 postmenopausal women with osteoporosis in the age group 45-60 years and 60 healthy postmenopausal women (normal bone mineral density) in the same age group were included in the study. Urinary hydroxyproline levels were significantly increased (P < 0.001) in PMO at baseline level as compared to control group. These levels were decreased significantly (P < 0.001) post therapy in PMO patients. Serum vitamin C levels were significantly decreased (P < 0.001) in PMO patients at baseline level as compared to controls. No significant change occurred of serum vitamin C level post therapy. Raised excretion of hydroxyproline at the baseline level might be due to increased degradation of collagen type I from the bone matrix in osteoporosis. Breakdown of collagen seems to be lowered as reflected by lowering of hydroxyproline excretion post antiresorptive therapy. Alteration in the concentration of this marker can be very well utilized to monitor the effectiveness of therapy. Thus simple, direct urinary assay to measure bone resorption is very useful in monitoring the therapy in PMO and may become an integral part of the management of osteoporosis.

Modulatory effect of cod liver oil on bone mineralization in overiectomized female Sprague Dawley rats

Osteoporosis represents a major public health problem through its association with fragility fractures, primarily of the hip, spine and distal forearm. The risk of osteoporosis increased in postmenopausal women due to decline in estrogen levels. Replicable hormone therapy is associated with undesirable side effects. Cod liver oil (CLO) is a rich source of docosahexaenoic acid eicosapentaenoic acid linolenic acid and vitamins A, E and D. In this study, the effect of CLO will be tested in the prevention of bone loss in the ovariectomized (OVX) female rats. One group of OVX rats (n = 12) received an estrogen implantation at the time of operation and the second group was supplemented orally with CLO (200 μl/kg body weight) daily for 8 weeks. At the end of the experiment, blood was analysed for serum calcium, phosphorous, bone-specific alkaline phosphatase, osteocalcin and estrogen and femur for calcium determination. Estrogen implantation as well as CLO supplementation in OVX rats increased the calcium level in femur as compared with sham rats (p < 0.05). It is concluded that supplementation of CLO have a positive effect on bone mineralization in rat, and this could offer a new strategy to avoid the side effects of replaceable hormonal therapy.

Osteocalcin-insulin relationship in obese children: a role for the skeleton in energy metabolism

OBJECTIVE

Osteocalcin is a bone-specific protein secreted by osteoblasts and often used as a bone formation biomarker. Rodent studies have reported a hormonal role of osteocalcin on glucose metabolism, increasing insulin secretion and sensitivity and increasing energy expenditure. However, it is unknown whether osteocalcin fulfils the same function in humans.

METHODS

We investigated the relationship between serum osteocalcin and insulin concentrations in 27 prepubertal obese children (9-12 years old) randomly divided into two groups, one of which entered a physical training programme, and 16 nonobese control children. Whole body bone mineral density (WB-BMD), serum osteocalcin, circulating insulin and adiponectin were measured at baseline and after 6 months.

RESULTS

Trained and untrained obese children had higher WB-BMD than controls at baseline. Trained children also displayed a significant insulin increase and a significant adiponectin decrease while osteocalcin was increased compared to untrained obese children. Significant linear correlations between WB-BMD and adiponectin, delta BMD (variation between baseline and after-training values) and delta adiponectin, insulin and osteocalcin, delta insulin and delta osteocalcin, delta insulin and delta under-carboxylated osteocalcin were found only in trained obese children with no significant relationship in control and untrained obese children.

CONCLUSIONS

In trained obese children, correlations indicate that when BMD is increased, osteocalcin is increased and insulin lowered. This suggests that increased BMD is associated with increased energy metabolism and a decreased level of insulin. We thus report statistically significant relationships between the skeleton (osteocalcin) and energy metabolism (insulin), suggesting a regulatory hormonal loop including osteocalcin and insulin.

The effects of Labisia pumila var. alata on bone markers and bone calcium in a rat model of post-menopausal osteoporosis

AIM OF THE STUDY

Postmenopausal osteoporosis is mainly treated with estrogen replacement therapy (ERT). However, ERT causes side effects, mainly breast cancer, uterine cancer and thromboembolic problems. Labisia pumila var. arata (LPva), a herb with phytoestrogenic effects has the potential to be used as an alternative agent to ERT. This study was conducted to determine the effects of LPva on bone biochemical markers and bone calcium content in ovariectomised rats.

MATERIALS AND METHODS

Thirty two Wistar rats were divided into 4 groups, with 8 rats in each group. The first group was sham operated (Sham), the second group was ovariectomised (OVX), the third (LPva) and fourth group (ERT) were also ovariectomised and given LPva 17.5 mg/kg and Premarin(®) 64.5 μg/kg, respectively. Blood samples were taken before and after treatment to measure osteocalcin and C-terminal telopeptide of type 1 collagen levels using ELISA while the fifth lumbar bone samples were taken to measure bone calcium content using the Atomic Absorption Spectrophotometer (AAS).

RESULTS

The osteocalcin levels were significantly higher in both the LPva and ERT groups compared to the OVX group. The CTX levels were significantly lower in both the LPva and ERT groups compared to the OVX group. However, only the ERT group had significantly higher bone calcium level compared to the OVX group.

CONCLUSION

The supplementation of 17.5 mg/kg of LPva to ovariectomised rats for 8 weeks was able to prevent the changes in bone biochemical markers but failed to prevent the bone calcium loss induced by ovariectomy.

Consistency of bone turnover marker and calcium responses to parathyroid hormone (1-84) therapy in postmenopausal osteoporosis

We investigated whether those who experience the greatest increases in bone turnover in response to parathyroid hormone (PTH) therapy are the same as those who experience elevations in calcium levels. Baseline and follow-up procollagen type I N propeptide (PINP), bone-specific alkaline phosphatase (BAP), C-terminal telopeptide (CTX), and serum and urinary calcium levels were analyzed post hoc from the 119 postmenopausal women with osteoporosis randomized to PTH(1-84) in the Parathyroid Hormone and Alendronate trial. Short-term changes in the markers of bone turnover were highly correlated with one another (r=0.57-0.87, p<0.001). In contrast, change in serum calcium correlated only modestly with changes in markers of formation (r=0.22-0.30, p≤0.02) and did not correlate significantly with change in CTX (r=0.13, p=0.18). Participants who experienced hypercalcemia experienced greater 3-mo changes in BAP than those who did not (78% vs. 42% increase in BAP, p=0.04), with similar trends for PINP and CTX. In conclusion, the use of 1 marker of bone turnover, rather than multiple markers, may be sufficient to assess biochemical response to PTH(1-84). The relationship between bone turnover marker and calcium responses to PTH(1-84) is modest and does not suggest a profound, broadly heightened responsiveness of certain individuals to therapy.