Biochemical markers of bone turnover are influenced by recently sustained fracture

Modulation of calcium-influx by carboxymethyl tamarind‑gold nanoparticles promotes biomineralization for tissue regeneration

Gold nanoparticles (AuNPs) have been reported to modulate bone tissue regeneration and are being extensively utilized in biomedical implementations attributable to their low cytotoxicity, biocompatibility and simplicity of functionalization. Lately, biologically synthesized nanoparticles have acquired popularity because of their environmentally acceptable alternatives for diverse applications. Here we report the green synthesis of AuNPs by taking the biopolymer Carboxymethyl Tamarind (CMT) as a unique reducing as well as a stabilizing agent. The synthesized CMT-AuNPs were analyzed by UV-vis spectrophotometer, DLS, FTIR, XRD, TGA, SEM and TEM. These results suggest that CMT-AuNPs possess an average size of 19.93 ± 8.52 nm and have long-term stability. Further, these CMT-AuNPs promote the proliferation together with the differentiation and mineralization of osteoblast cells in a "dose-dependent" manner. Additionally, CMT-AuNPs are non-toxic to SD rats when applied externally. We suggest that the CMT-AuNPs have the potential to be a suitable and non-toxic agent for differentiation and mineralization of osteoblast cells in vitro and this can be tested in vivo as well.

Effect of replacing dicalcium phosphate with mono-dicalcium phosphate to supplement phosphorus on laying performance, phosphorus-calcium metabolism and bone metabolism of aged laying hens

The objective of this study was to evaluate the effect of replacing dicalcium phosphate (DCP) with mono-dicalcium phosphate (MDCP) to formulate low-phosphorus (P) diets on laying performance, egg quality, phosphorus-calcium metabolism, and bone metabolism of 69-78-week-old aged laying hens. Hy-Line Brown laying hens (n = 1,350, 69 weeks old) were randomly assigned to six treatments, each with five replicates of 45 hens. A corn-soybean meal-based diet was formulated to contain 0.12% non-phytate phosphorus (NPP), 3.81% calcium (Ca), and 1,470 FTU/kg phytase. The control group (CON) was supplemented with DCP inorganic phosphorus (Pi) at the NPP level of 0.20% (dietary NPP levels of 0.32%). Test groups (T1-T5) were supplemented with MDCP Pi at NPP levels of 0.07%, 0.11%, 0.15%, 0.18, and 0.20% (dietary NPP levels of 0.19, 0.23, 0.27, 0.30, and 0.32%, respectively). Calcium carbonate levels were adjusted to ensure all experimental diets contained the same Ca levels (3.81%). The feeding trial lasted 10 weeks, with hens increasing in age from 69 to 78 weeks. When supplemented with 1,470 FTU/kg phytase, extra DCP Pi or MDCP Pi did not affect (p > 0.05) laying performance (day laying rate, average egg weight, feed intake, feed-to-egg mass ratio, broken egg rate), egg quality (eggshell strength, albumen height, haugh units), or serum P, Ca, copper (Cu), iron (Fe), zinc (Zn), and manganese (Mn) levels. However, when laying hens were fed MDCP Pi (NPP levels of 0.07 to 0.20%), yolk color improved (p = 0.0148). The tibia breaking strength was significantly higher (p < 0.05) in the 0.18 and 0.20% NPP MDCP Pi groups than in the 0.20% NPP DCP Pi group. The breaking strength, Ca content, and P content of tibia in 0.11% and 0.15% NPP MDCP Pi hens were not significantly (p > 0.05) different from those in 0.20% NPP DCP Pi hens. Hens fed 0.07% NPP MDCP Pi had higher (p < 0.01) serum levels of osteoprotegerin (OPG), type-I collagen c-telopeptide (CTX-I), and tartrate-resistant acid phosphatase 5b (TRACP-5b) than those in all other groups. Serum levels of TRACP-5b and CTX-I in the 0.11% and 0.15% NPP MDCP Pi group were significantly lower than those in 0.18 and 0.20% NPP MDCP Pi groups and the 0.20% NPP DCP Pi group (p < 0.0001). Hens fed 0.07% and 0.11% NPP MDCP Pi had higher (p < 0.05) serum levels of parathyroid hormone (PTH) than those in all other groups. No differences were detected in serum calcitonin (CT), 1,25-dihydroxy-vitamin D3 (1,25-(OH)2D3), bone alkaline phosphatase (BAP), osteocalcin(OCN), and osteopontin (OPN) among all groups (p > 0.05). The expression of P transporters type IIa Na/Pi cotransporter (NaPi-IIa) in 0.11% and 0.15% NPP MDCP Pi hens were higher than those in 0.20% NPP MDCP Pi group and 0.20% NPP DCP Pi group (p < 0.05). The results indicated that both renal P reabsorption and bone resorption were involved in adapting to a low-P diet. In summary, when MDCP was used instead of DCP to supplement P, NPP levels could be reduced to 0.11% (dietary NPP level of 0.23%) without negative effects on laying performance and skeletal health of aged hens. In addition, MDCP was more beneficial than DCP for tibia quality. The results of the current study would provide references for the application of MDCP in low-P diets of aged laying hens.

Myosin heavy chain-derived peptide of Gadus morhua promotes proliferation and differentiation in osteoblasts and bone formation and maintains bone homeostasis in ovariectomized mice

Gadus morhua is an important commercial fish rich in nutrients required for daily metabolism. However, the regulation of G. morhua peptides (GMP) on osteoblast growth remains unclear. In order to clarify the regulatory effects of GMP on osteoblasts, the effects of GMP on the growth of MC3T3-E1 cells were investigated, and the osteogenic peptides were identified and screened. The results showed that GMP promoted the proliferation and differentiation of osteoblasts by regulating the BMP/WNT signaling pathway at concentrations of 1-100 μg mL^-1. Molecular docking studies showed that a decapeptide, MNKKREAEFQ (P-GM-1), had a high affinity for integrins 3VI4 and 1L5G (-CDOCKER interaction energy: 161.30, 212.27 kcal mol^-1). Additionally, the proliferation rate of MC3T3-E1 cells was increased by 27%, and ALP activity was significantly increased under P-GM-1 treatment (100 μg mL^-1). Moreover, P-GM-1 promotes bone formation, maintains bone homeostasis, and prevents osteoporosis in ovariectomized mice by regulating the BMP/Smad signaling pathway. This study confirmed the potential of GMP in the regulation of bone mineral density and provided a certain theoretical basis for the development of anti-osteoporosis active factors from GMP.

The evolution of the adolescent growth spurt: Urinary biomarkers of bone turnover in wild chimpanzees (Pan troglodytes)

Life history theory addresses how organisms balance development and reproduction. Mammals usually invest considerable energy into growth in infancy, and they do so incrementally less until reaching adult body size, when they shift energy to reproduction. Humans are unusual in having a long adolescence when energy is invested in both reproduction and growth, including rapid skeletal growth around puberty. Although many primates, especially in captivity, experience accelerated growth in mass around puberty, it remains unclear whether this represents skeletal growth. Without data on skeletal growth in nonhuman primates, anthropologists have often assumed the adolescent growth spurt is uniquely human, and hypotheses for its evolution have focused on other uniquely human traits. The lack of data is largely due to methodological difficulties of assessing skeletal growth in wild primates. Here, we use two urinary markers of bone turnover-osteocalcin and collagen-to study skeletal growth in a large, cross-sectional sample of wild chimpanzees (Pan troglodytes) at Ngogo, Kibale National Park, Uganda. For both bone turnover markers, we found a nonlinear effect of age, which was largely driven by males. For male chimpanzees, values for osteocalcin and collagen peaked at age 9.4 years and 10.8 years, respectively, which corresponds to early and middle adolescence. Notably, collagen values increased from 4.5 to 9 years, suggesting faster growth during early adolescence compared to late infancy. Biomarker levels plateaued at 20 years in both sexes, suggesting skeletal growth continues until then. Additional data, notably on females and infants of both sexes, are needed, as are longitudinal samples. However, our cross-sectional analysis suggests an adolescent growth spurt in the skeleton of chimpanzees, especially for males. Biologists should avoid claiming that the adolescent growth spurt is uniquely human, and hypotheses for the patterns of human growth should consider variation in our primate relatives.

Can frailty in conjunction with FRAX identify additional women at risk of fracture - a longitudinal cohort study of community dwelling older women

BACKGROUND

Fracture risk assessment is still far from perfect within the geriatric population. The overall aim of this study is to better identify older women at risk for fractures, using a quantitative measure of frailty in conjunction with the web-based Fracture Risk Assessment Tool (FRAX®).

METHODS

This study was performed in the Osteoporosis Risk Assessment (OPRA) cohort of n = 1023, 75-year-old women followed for 10-years. A frailty index (FI) of 'deficits in health' was created, and FRAX 10-year probability for major osteoporotic and hip fractures was calculated and bone mineral density measured. Incident fractures were continuously registered for 10-years. Receiver Operating Characteristic (ROC) curves were used to compare FI, FRAX and the combination FI + FRAX as instruments for risk prediction. Discriminative ability was estimated by comparing Area Under the Curve (AUC). In addition, using guidelines from the Swedish Osteoporosis Foundation, a category of low risk women who would not have been recommended for pharmacological treatment (non-treatment group) was identified, categorized by frailty status and for relative risk analysis, hazard ratios (HR) and 95% confidence intervals were calculated using Cox proportional hazard regressions.

RESULTS

For hip fracture, FRAX and frailty performed almost equally (HIP AUC 10y: 0.566 vs. 0.567, p = 0.015 and p = 0.013). Next, FI was used in conjunction with FRAX; proving marginally better than either score alone (AUC 10y: 0.584, p = 0.002). Comparable results were observed for osteoporotic fracture. In the non-treatment group (564 women), being frail was associated with higher 10y hip fracture risk (HR 2.01 (1.13-3.57)), although failing to reach statistical significance for osteoporotic fracture (HR 1.40 (0.97-2.01). The utility of measuring frailty was also demonstrated when using T-score as an index of bone density to define fracture risk. Among n = 678 non-osteoporotic women, frailty added to the 10-year fracture risk (Hip; HR 2.22 (1.35-3.71); Osteoporotic fracture; HR 1.57 (1.15-2.14)).

CONCLUSIONS

While the addition of frailty to FRAX marginally improved fracture prediction, applying a frailty measurement to a group of 'low risk' women, identified a set of individuals with high actual hip fracture risk that would not be prioritized for pharmacological treatment. Further cost-benefit analysis studies are needed to formally test potential benefit.

Bone Turnover Marker Profiling and Fracture Risk in Older Women: Fracture Risk from Age 75 to 90

PURPOSE

A major challenge in osteoporosis is to identify individuals at high fracture risk. We investigated six bone turnover markers (BTMs) to determine association with specific fracture types; the time-frame for risk prediction and whether these are influenced by age at assessment.

METHODS

Population-based OPRA cohort (n = 1044) was assessed at ages 75, 80, 85 and fractures documented for up to 15 years. Six BTMs were analyzed at each time-point (N-terminal propeptide of type I collagen, PINP; total osteocalcin, OC; bone-specific alkaline phosphatase, BALP; C-terminal telopeptide of type I collagen, CTX; tartrate-resistant acid phosphatase 5b, TRAcP5b; urinary osteocalcin). Hazard ratios (HR) for any, major osteoporotic, vertebral and hip fractures were calculated as short (1, 2, 3 years) and long-term risk (5, 10, 15 years).

RESULTS

At 75 year, high CTX levels were associated with an increased risk of all fractures, including major osteoporotic fractures, across most time-frames (HRs ranging: 1.28 to 2.28). PINP was not consistently associated. Urinary osteocalcin was consistently associated with elevated short-term risk (HRs ranging: 1.83-2.72). Other BTMs were directionally in accordance, though not all statistically significant. BTMs were not predictive for hip fractures. Association of all BTMs attenuated over time; at 80 year none were associated with an increased fracture risk.

CONCLUSION

CTX, urinary OC and TRAcP5b are predictive for fracture in a 1 to 3 year, perspective, whereas in the long-term or above age 80 years, BTMs appear less valuable. Resorption markers, particularly CTX, were more consistently associated with fracture risk than formation markers in the very elderly.

Association between bone turnover markers and periodontitis: A population-based cross-sectional study

AIM

To examine the associations between bone turnover markers and periodontitis in two cross-sectional population-based studies.

MATERIALS AND METHODS

We used data from two independent adult samples (N = 4993), collected within the Study of Health in Pomerania project, to analyse cross-sectional associations of N-procollagen type 1 amino-terminal propeptide (P1NP), C-terminal cross-linking telopeptide, osteocalcin, bone-specific alkaline phosphatase (BAP), fibroblast growth factor 23, wingless-type mouse mammary tumour virus integration site family member 5a (WNT5A), and sclerostin values with periodontitis. Confounder-adjusted gamma and fractional response regression models were applied.

RESULTS

Positive associations were found for P1NP with mean pocket probing depth (PPD; e β = 1.008 ; 95% confidence interval [CI]: 1.001-1.015), mean clinical attachment loss (mean CAL; e β = 1.027 ; 95% CI: 1.011-1.044), and proportion of sites with bleeding on probing (%BOP; e β = 1.055 ; 95% CI: 1.005-1.109). Similar associations were seen for BAP with %BOP ( e β = 1.121 ; 95% CI: 1.042-1.205), proportion of sites with PPD ≥4 mm (%PPD4) ( e β = 1.080 ; 95% CI: 1.005-1.161), and sclerostin with %BOP ( e β = 1.308 ; 95% CI: 1.005-1.704). WNT5A was inversely associated with mean PPD ( e β = 0.956 ; 95% CI: 0.920-0.993) and %PPD4 ( e β = 0.794 ; 95% CI: 0.642-0.982).

CONCLUSIONS

This study revealed scattered associations of P1NP, BAP, WNT5A, and sclerostin with periodontitis, but the results are contradictory in the overall context. Associations reported in previous studies could not be confirmed.

The impact of acute fracture on interpretation of bone turnover marker measurements for patients starting anti-resorptive therapies

INTRODUCTION

Bone turnover markers (BTM) are used in evaluating patients' response to anti-resorptive agents (ARA). Fracture and its healing process, however, can influence the measurements, which might make their interpretation difficult in patients with a recent fracture. We aimed to evaluate the effect of oral ARA on changes in BTM levels in patients with a recent distal radius fracture (DRF).

METHODS

In 143 women who had a new DRF and then received oral ARA including selective estrogen receptor modulator (SERM, n = 101), and bisphosphonate (n = 42), we measured serum cross-linked C-telopeptides of type I collagen (CTXI) and osteocalcin, at baseline and six months, as well as lumbar and total hip bone mineral density (BMD) at baseline and one year after fracture. We determined the predictive value of BTM at six months in determining one-year responses in BMD.

RESULTS

Both BTM levels decreased significantly at six months, with the average decrease of 27 ± 63% for CTX-I and 11% ± 37% for osteocalcin. The percent changes of BTM at six months were independent predictors of the BMD change. Cutoff points of 50.0% CTX-I decrease and 23.5% for osteocalcin decrease had the highest sensitivities and specificities for detecting BMD responders for bisphosphonate users, but cutoffs could not be found for SERM users.

CONCLUSION

Although a fresh fracture can influence BTM, ARA therapy significantly reduced their levels and their percent change at six months could predict BMD improvement at one year. However, adjusted cutoff points can be necessary to increase sensitivity for detecting patients responsive to ARA treatment after a new DRF.

Bone Turnover Markers and Bone Mineral Density to Predict Osteoporotic Fractures in Older Women: A Retrospective Comparative Study

Objective

To investigate the clinical significance of the detection of bone mineral density (BMD) and bone turnover markers (BTM) in older women with osteoporosis, and to compare their predictive power for osteoporotic fractures (OF).

Methods

In this retrospective study, 96 patients with OF and 107 patients with osteoporosis who were hospitalized in the Department of Orthopedics at the First Affiliated Hospital of Chengdu Medical College were examined from October 2017 to February 2019. All selected patients were divided into either the fracture group (96 cases, 47.3%) or the non‐fracture group (107 cases, 52.7%). BMD was measured by dual‐energy X‐ray absorptiometry (DXA). BTM were detected by electrochemical luminescence: aminoterminal propeptide of type I procollagen (PINP), β‐cross‐linked C‐telopeptide of type I collagen (β‐CTX), and molecular fragment of osteocalcin N terminal (N‐MID). Bone metabolism‐related indicators were detected, including alkaline phosphatase (ALP), calcium (Ca), and phosphorus (P). Independent‐samples t‐tests were used to compare the measurement data between the two groups, one‐way ANOVA to compare the gaps between groups, and binary logistic regression to analyze the correlation of BMD and BTM with OF.

Results

There were no significant differences in age, weight, height, body mass index, age, and time of menopause between the two groups. There were a total of 71 cases (35.0%) in group A (60–70 years), 80 cases (39.4%) in group B (71–80 years), and 52 cases (25.6%) in group C (81–90 years). The fracture group was compared with the non‐fracture group for BMD in the lumbar (0.75 ± 0.05 vs 0.88 ± 0.13, 0.75 ± 0.16 vs 0.87 ± 0.09, 0.74 ± 0.21 vs 0.87 ± 0.12 g/cm²; P < 0.05), BMD in the hip (0.62 ± 0.16 vs 0.74 ± 0.14, 0.61 ± 0.15 vs 0.73 ± 0.0, 0.58 ± 0.13 vs 0.73 ± 0.08 g/cm²; P < 0.05), PINP (83.7 ± 5.7 vs 74.8 ± 5.0, 80.7 ± 4.1 vs 72.1 ± 5.1, 81.2 ± 7.0 vs 68.7 ± 6.3 ng/mL, P < 0.05), and β‐CTX (829.7 ± 91.5 vs 798.8 ± 52.2, 848.1 ± 71.2 vs 812.4 ± 79.0, 867.3 ± 53.1 vs 849.1 ± 67.2 pg./mL, P < 0.05). N‐MID (19.0 ± 6.7 vs 21.3 ± 9.7, 16.2 ± 7.0 vs 18.0 ± 5.3 ng/mL, P < 0.05) in the fracture cases was lower than in the non‐fracture cases for groups B and C, and there was statistical significance. Among the fracture cases, PINP in group A was higher than in group B and C, and β‐CTX in group C was higher than in group A and B (P < 0.05). There was no significant difference in the ALP, P, and Ca between the two groups (P > 0.05). Binary logistic regression analysis showed that for BMD in the lumbar and hip, β‐CTX and OF were significantly correlated (respectively, odds ratio [OR] = −4.182, 95% confidence interval [CI] 1.672–3.448; OR = 6.929, 95% CI 2.586–12.106; OR = 7.572, 95% CI 1.441–3.059), and the differences were statistically significant. PINP and N‐MID were correlated with OF (respectively, OR = 4.213, 95% CI 0.978–1.005; OR = 2.510, 95% CI 1.070–1.134, P > 0.05), the difference was not statistically significant.

Conclusion

Osteoporotic older women, with lower bone density and higher β‐CTX, are more likely to incur OF. β‐CTX is better than BMD at predicting OF and can help in its management and in implementing interventions in high‐risk populations.

Systemic Bone Loss After Fracture

A history of prior fracture is the most reliable indicator of prospective fracture risk. Increased fracture risk is not confined to the region of the prior fracture, but is operant at all skeletal sites, providing strong evidence of systemic bone loss after fracture. Animal and human studies suggest that systemic bone loss begins shortly after fracture and persists for several years in humans. In fact, bone quantity and bone quality may never fully return to their pre-fracture levels, especially in older subjects, demonstrating a need for improved understanding of the mechanisms leading to systemic bone loss after fracture in order to reduce subsequent fracture risk. Although the process remains incompletely understood, mechanical unloading (disuse), systemic inflammation, and hormones that control calcium homeostasis may all contribute to systemic bone loss. Additionally, individual factors can potentially affect the magnitude and time course of systemic bone loss and recovery. The magnitude of systemic bone loss correlates positively with injury severity and age. Men may also experience greater bone loss or less recovery than women after fracture. This review details the current understanding of systemic bone loss following fracture, including possible underlying mechanisms and individual factors that may affect this injury response.

Bone Turnover in Vertebral Fractures: Does it Effect the Decision of Surgery?

Background and Aim:

Instrumentation is commonly used in spinal surgery to stabilize the fracture. In the present study, we aimed to compare the early and late changes seen in bone production and degradation products in patients with traumatic spinal fracture who had been treated surgically or conservatively.

Materials and Methods:

Forty-three patients were admitted to the Neurosurgery Department with thoracolumbar or lumbar fracture in this prospective study. Patients were divided into two groups of surgically treated (n = 23) and nonsurgically/conservatively treated (n = 20) patients. The early and late changes seen in bone production and degradation products were compared in patients with traumatic spinal fracture who had been treated surgically or conservatively.

Results:

In conservatively treated patients, although osteocalcin level was slightly increased and deoxypiridinoline (DPD)/creatinine was slightly decreased after the treatment, the difference was not statistically significant (P = 0.08 and P = 0.539, respectively). There is no significant difference between admission time, posttreatment late period osteocalcin level, and DPD/creatinine ratio between the two group of patients (P = 0.215 and P = 0.236, respectively).

Conclusion:

We suggest that the healing and fusion processes in fractured vertebrae not only followed by the radiological examination but also by noninvasive biochemical changes seen in the serum levels of bone formation and resorption markers.

Correlation of Serum CCL3/MIP-1α Levels with Disease Severity in Postmenopausal Osteoporotic Females

Background:

The pro-inflammatory protein chemokine cytokine ligand 3 is well established as a vital regulator of bone resorption and osteoclast stimulation.

Aims:

To investigate if serum cytokine ligand 3 levels correlated with disease severity in postmenopausal osteoporotic women.

Study Design:

Cross-sectional study.

Methods:

Eighty-two postmenopausal osteoporotic women, 76 postmenopausal non-osteoporotic women, and 80 healthy women of childbearing age were recruited. The total hip, femoral neck, and L1-L4 spine bone mineral density were assessed by dual-energy X-ray absorptiometry. Serum cytokine ligand 3 concentrations were examined using a commercial enzyme-linked immunosorbent assay kit. Serum inflammatory cytokine interleukin-6, tumor necrosis factor-alpha, and the bone metabolic markers, carboxy-terminal crosslinked and tartrate-resistant acid phosphatase 5b were also examined. Scores on both the visual analogue scale and the Oswestry Disability Index were utilized to assess clinical severity.

Results:

Patients in the postmenopausal osteoporotic group had significantly increased serum cytokine ligand 3 levels compared with those in both the postmenopausal non-osteoporotic group (40.9±15.1 pg/mL vs 24.2±8.7 pg/mL, p<0.001) and control group (40.9±15.1 pg/mL vs 23.9±9.1 pg/mL, p<0.001). Serum cytokine ligand 3 levels negatively correlated with bone mineral density at the total hip (r=-0.345, p=0.002), femoral neck (r=-0.329, p=0.003), and L1-L4 lumbar spine (r=-0.354, p=0.001) and positively correlated with visual analogue scale scores (r=0.413, p<0.001) and the Oswestry Disability Index (r=0.360, p<0.001). Moreover, serum cytokine ligand 3 levels were correlated with increased tumor necrosis factor-alpha (r=0.305, p=0.005), interleukin-6 (r=0.288, p=0.008), terminal crosslinked and tartrate-resistant acid phosphatase 5b (r=0.371, p<0.001), and carboxy-terminal crosslinked (r=0.317, p=0.004) levels. All correlations were still significant after adjusting for both body mass index and age.

Conclusion:

Chemokine cytokine ligand 3 may be a useful biomarker that can be used to predict disease severity of postmenopausal osteoporosis. Therapies targeting cytokine ligand 3 and its related signaling pathways to inhibit and delay the osteoclastogenesis process deserve further investigation.

Characteristics of bone biochemical indices in predicting secondary osteoporotic fracture after intertrochanteric fracture in elderly women

BACKGROUND

This study aimed to explore the characteristics of bone biochemical indices, including bone mineral density (BMD), metabolic markers in elderly women with osteoporotic intertrochanteric fracture and their relevance in secondary fracture.

METHODS

The standard for follow-up from 58 elderly women was established to analyse the BMD in the injured hip, healthy hip, and the vertebra at 1 week and 12 months after fracture. The serum levels of total procollagen type N-terminal propeptide (tPINP) and the age-related type I cross linked C-telopeptide (β-CTX) were recorded and compared between those patients with and without secondary fractures within 12 months.

RESULTS

Twelve months after fracture, the serum levels of tPINP and β-CTX were significantly higher than the baseline values (p < 0.01). The tPINP baseline in patients with secondary fracture was significantly lower than that in the rest patients without secondary fracture (p < 0.01). The β-CTX baseline was notably higher than that without secondary fracture (p < 0.01). BMD values of the three periods had no significantly difference.

CONCLUSION

The serum levels of tPINP and β-CTX are of great value in earlier and more sensitively reflecting the condition of bone turnover in body. Meanwhile, they can predict the subsequent fracture risk more accurately combined with a lower BMD.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Besides BMD, bone microstructure and remodeling levels can be accurately measured by bone biochemical indices. The main objective of this research is to explore the change of BMD and the serum level of bone biochemical indices of elderly women who suffered unilateral intertrochanteric fracture within 12 months. Simultaneously, with aim to better obtain bone remodeling level and predict more accurately the risk of a secondary osteoporotic fracture, bone biochemical indices of these patients, who undergo secondary osteoporotic fracture or not, are collected during follow-up and compared respectively.

Lower serum P1NP/βCTX ratio and hypoalbuminemia are independently associated with osteoporotic nonvertebral fractures in older adults

Purpose

To estimate the discriminative value of serum P1NP/βCTX ratio and albumin levels in hospitalized orthogeriatric patients with and without nonvertebral fractures.

Methods

In 1,239 orthogeriatric patients (mean age 78.1±9.52 years, 69.1% women) including 854 (68.9%) with osteoporotic nonvertebral fractures (455 [36.7%] with hip fracture [HF]) and 385 (31.1%) without fractures, markers of bone formation (procollagen type 1 N-terminal propeptide [P1NP], osteocalcin [OC], and bone resorption (beta-C-terminal cross-linking telopeptide of type 1 collagen [βCTX]), indices of mineral metabolism, and parameters of liver and renal functions were assessed; data on clinical and laboratory characteristics were collected prospectively.

Results

Both lower serum P1NP/βCTX ratio and albumin concentration (as continuous or categorical variables) were independently associated with fracture presence in multivariate logistic regressions. Compared with the highest P1NP/βCTX tertile, the prevalence of HF, after adjustment for multiple covariates, was 3-fold higher in the lowest tertile and 1.5 times higher in the middle tertile; presence of any fracture was 2.3- and 1.6-fold higher, respectively; patients with albumin levels in the lowest tertile had multivariate odds ratio (OR) of 4.6 for HF and 2.8 for any fracture, in the middle tertile the ORs were 2.2 and 1.3, respectively. The P1NP/βCTX <100.0 (median) and hypoalbuminemia (<33 g/L) demonstrated area under the curve values for HF of 0.802 and 0.806, respectively, and for any fractures of 0.711 and 0.706, respectively. When both characteristics were combined, the ORs for HF or any fracture, compared with the nonfractured group, were 7.8 and 3.2, respectively, with an accuracy of 79.6% and 71.6%, respectively.

Conclusions

In orthogeriatric patients, both serum P1NP/βCTX ratio and albumin levels demonstrated an inverse dose–effect relationship with the prevalence of nonvertebral fractures and independently indicated fracture presence with acceptable discriminatory power. Lower P1NP/βCTX (<100) and hypoalbuminemia could be useful simple additive prognostic tools for fracture risk stratification in the elderly.

Changes in the Dickkopf-1 and tartrate-resistant acid phosphatase 5b serum levels in preschool children with nephrotic syndrome

The aim of the present study was to investigate the changes in the serum Dickkopf-1 (DKK-1) and tartrate-resistant acid phosphatase 5b (TRACP-5b) levels in preschoolers with nephrotic syndrome (NS). A total of 50 preschoolers (3-5 years old) with NS and 20 healthy preschoolers (control group) were enrolled in the prospective single-center study. The patients with NS received glucocorticoid treatment and the control group received no treatment. The levels of serum calcium, phosphorus, TRACP-5b, DKK-1 and 25-hydroxyvitamin D3 were measured at baseline and at 3 and 6 months in all the subjects. The levels of DKK-1 and TRACP-5b were significantly higher in the NS group prior to treatment when compared to the control group (P<0.05), but did not differ significantly between the two groups following treatment (P>0.05). Therefore, DKK-1 and TRACP-5b can be used as biomarkers of bone formation and bone resorption, respectively, in the early evaluation of bone metabolism.

Gypsum-based biomaterials: Evaluation of physical and mechanical properties, cellular effects and its potential as a pulp liner

This in vitro study aimed to evaluate setting time and compressive strength of gypsum-based chitosan biomaterials and its effect on proliferation of stem cells from human exfoliated deciduous teeth (SHED) and alkaline phosphatase (ALP) activity. Pure-GYP was mixed with water (2.5 g: 1.9 mL); Gyp-CHT was prepared with gypsum, chitosan, and water (2.5 g: 0.285 g: 1.9 mL). Cell viability and ALP activity were assessed at different periods. Data were analyzed using SPSS (p<0.05). The setting times were 2.7 min and 2.8 min for pure-GYP and Gyp-CHT, respectively. Significantly higher compressive strength was observed with Gyp-CHT. SHED treatments with both materials were not cytotoxic. ALP was consistently higher in the treated groups compared with the control. Cellular attachments were evident with SEM. Excellent cellular viability with pure-GYP and Gyp-CHT, as well as increased ALP activities, suggested the possibility of tertiary dentin formation. Further studies are necessary to evaluate the biomaterials for its pulp protective potentialities.

[Clinical heterogeneity of atypical fractures during prolonged use of bisphosphonates--risk factors and bone turnover markers]

We describe four cases of atypical femoral fractures treated at the Department of Endocrinology, Hospital de Clínicas, Federal University of Paraná (SEMPR) which, although characteristic of this type of fracture, presented clinical peculiarities that should be considered and serve as a warning in these patients, such as: late diagnosis with maintenance of bisphosphonates; absence of co-morbidities with excellent result; failure of fracture healing; use of anabolic medication after the fracture and the use of bone turnover markers at the follow up.

Characteristics of bone turnover in the long bone metaphysis fractured patients with normal or low Bone Mineral Density (BMD)

The incidence of osteoporotic fractures increases as our population ages. Until now, the exact biochemical processes that occur during the healing of metaphyseal fractures remain unclear. Diagnostic instruments that allow a dynamic insight into the fracture healing process are as yet unavailable. In the present matched pair analysis, we study the time course of the osteoanabolic markers bone specific alkaline phosphatase (BAP) and transforming growth factor β1 (TGFβ1), as well as the osteocatabolic markers crosslinked C-telopeptide of type-I-collagen (β-CTX) and serum band 5 tartrate-resistant acid phosphatase (TRAP5b), during the healing of fractures that have a low level of bone mineral density (BMD) compared with fractures that have a normal BMD. Between March 2007 and February 2009, 30 patients aged older than 50 years who suffered a metaphyseal fracture were included in our study. BMDs were verified by dual energy Xray absorptiometry (DXEA) scans. The levels of BTMs were examined over an 8-week period. Osteoanabolic BAP levels in those with low levels of BMD were significantly different from the BAP levels in those with normal BMD. BAP levels in the former group increased constantly, whereas the latter group showed an initial strong decrease in BAP followed by slowly rising values. Osteocatabolic β-CTX increased in the bone of the normal BMD group constantly, whereas these levels decreased significantly in the bone of the group with low BMD from the first week. TRAP5b was significantly reduced in the low level BMD group. With this work, we conduct first insights into the molecular biology of the fracture healing process in patients with low levels of BMD that explains the mechanism of its fracture healing. The results may be one reason for the reduced healing qualities in bones with low BMD.

Relationships between changes in bone mineral density or bone turnover markers and vertebral fracture incidence in patients treated with bazedoxifene

We analyzed the relationships between bone mineral density (BMD) or bone turnover marker (BTM) changes and vertebral fracture incidence in women treated with bazedoxifene using a post hoc analysis from a 3-year randomized, placebo-controlled study evaluating the effect of bazedoxifene (20 or 40 mg) on fracture risk reduction. BMD was assessed at baseline and every 6 months for 3 years. Osteocalcin and C-telopeptide of type I collagen were assessed at baseline and at 3, 12, and 36 months. Vertebral fractures were assessed with a semiquantitative visual assessment. Data were available for 5,244 women, of whom 3,476 were treated with bazedoxifene. Using a logistic regression analysis and the classical Li approach, the proportion of fracture incidence explained by BMD change after 3 years of bazedoxifene treatment was 29 % for the total hip and 44 % for the femoral neck. The proportion of treatment explained by lumbar BMD change could not be quantified accurately because of the significant interaction between treatment and change in BMD. With the same model, the 12-month BTM changes explained up to 29 % of the fracture risk reduction observed with the two forms of bazedoxifene. In women treated with bazedoxifene, changes in femoral neck BMD, hip BMD, or BTMs explained a moderate proportion of the fracture risk reduction observed during the 3 years of follow-up. However, BMD or BTM changes cannot be recommended for individual monitoring of women treated with bazedoxifene.

Characteristics of bone metabolism markers during the healing of osteoporotic versus nonosteoporotic metaphyseal long bone fractures: a matched pair analysis

PURPOSE

The activity and metabolism of fracture healing can be monitored quantitatively by measuring bone turnover markers (BTMs) in serum or urine. However, in osteoporotic bone, the exact metabolism processes during the healing of metaphyseal fractures remain unknown. There is no diagnostic approach which currently allows dynamic insight into the fracture healing processes in order to monitor the progression of healing and to assist in therapeutic decision making.

METHODS

Between March 2007 and February 2009, 30 patients over 50 years of age who suffered a metaphyseal fracture were included in our study. The levels of the osteoanabolic marker BAP (bone-specific alkaline phosphatase) and osteocatabolic marker β-CTX [crosslinked C-(CTX)-telopeptide-of-type-I-collagen] were monitored during the fracture healing of osteoporotic and nonosteoporotic fractures for a duration of 8 weeks.

RESULTS

After an initial decrease of BAP in the first week, the BAP level steadily increased through the fourth week in both groups. The levels of BAP in the osteoporotic group surpassed the healthy group. β-CTX steadily increased in healthy bone up to the fourth week; in osteoporotic bone, β-CTX first increased and, thereafter, decreased from the first week onwards.

CONCLUSIONS

In this work, the first molecular biological aspects of osteoporotic fracture healing have been uncovered, helping to explain the mechanisms of delayed fracture healing in osteoporotic bone. The early decrease of reduced β-CTX as well as elevated BAP during the healing process may be the first aspects within the delayed healing of osteoporotic bone. Further studies are necessary in order to achieve more detailed insight to fracture healing and to ascertain the progression of fracture healing as being essential (criteria) for therapeutic decision making.

Clinical use of bone turnover markers to monitor pharmacologic fracture prevention therapy

Monitoring of drug therapies to prevent fractures is controversial. Measurement of bone turnover markers has the potential to identify those with a suboptimal response to fracture prevention medication within a few months of its commencement. However, given the imprecision of currently commercially available assays of bone turnover markers, many individual persons who are “suboptimal medication responders” are likely to be misclassified as “adequate responders” or vice versa, depending on the cut point chosen to define suboptimal and adequate response. Before bone turnover markers can be recommended for routine use in clinical practice to monitor fracture prevention therapies, three advances are needed: 1) bone marker assays with better precision; 2) research establishing optimal cut points of bone marker levels to distinguish “suboptimal responders” from “adequate responders”; and 3) research establishing the incremental fracture reduction benefit from clinical interventions for “suboptimal responders” identified from bone marker measurements.

The safety and efficacy of early-stage bi-weekly alendronate to improve bone mineral density and bone turnover in chinese post-menopausal women at risk of osteoporosis

The efficacy and safety of early, low frequency antiresorptive drug intervention for osteopaenia on bone mineral density (BMD) and bone turnover in Chinese post-menopausal women at risk of developing osteoporosis were investigated. A total of 180 women aged 40 - 70 years were enrolled and equally randomized to receive either 70 mg alendronate once every 2 weeks plus 0.5 μg alfacalcidol daily (treatment group) or alfacalcidol 0.5 μg daily alone (control group) for 12 months. In the treatment group, lumbar spine and total hip BMD at 12 months had increased significantly from baseline and compared with the control group. There were also significant reductions in serum levels of the bone turnover biomarkers, bone-specific alkaline phosphatase and C-terminal telopeptide of type I collagen, compared with the control. No serious adverse events were observed in either group and safety profiles were similar. It was concluded that early intervention with 70 mg alendronate once every 2 weeks was safe, well tolerated and more effective than alfacalcidol alone (control) in increasing BMD and reducing bone turnover, and might prevent serious outcomes, such as fragility fractures, reduce rates of adverse effects and improve patient compliance.

Early changes in bone specific turnover markers during the healing process after vertebral fracture

BACKGROUND

The present study measured longitudinal changes in bone turnover markers in elderly patients with vertebral fracture and investigated the relationship among bone turnover markers, duration of bed rest and bone mineral density (BMD).

METHODS

Criteria for patient selection were 50 years in age and older, and presence of VF. Serum bone-specific alkaline phosphatase (BAP) was measured as a marker of bone formation. Urinary crosslinked N-terminal telopeptides of type I collagen (NTX) was measured as a marker of bone resorption. In principle, samples were collected just after injury, within 24 h, and 1, 2, 3, 5 and 8 weeks after. We also measured duration of bed rest and BMD.

RESULTS

The study population consisted of 42 cases. The average BMD of the lumbar vertebrae was 0.670 ± 0.174 g/cm2. Bed rest period was 17.9 ± 8.8 days. BAP showed significantly higher values at 2 and 3 weeks compared with the baseline value. Thereafter, BAP progressively decreased until 8 weeks. Urinary NTX was increased soon after the onset of pain with the same patterns in BAP. Urinary NTX values reached a peak at 3 weeks, and then they kept significantly higher values until 8 weeks. The peak value of serum BAP was affected by the duration of bed rest, although that of the urinary NTX was not. The peak values of serum BAP and urinary NTX showed negative correlations with the initial BMD values.

CONCLUSIONS

Bone turnover markers remained higher at 8 weeks, even patients symptom was healed after VF. Bone turnover markers were affected on physical activity and BMD.

Women with hip fracture experience greater loss of geometric strength in the contralateral hip during the year following fracture than age-matched controls

This study examined femur geometry underlying previously observed decline in BMD of the contralateral hip in older women the year following hip fracture compared to non-fractured controls. Compared to controls, these women experienced a greater decline in indices of bone structural strength, potentially increasing the risk of a second fracture.

INTRODUCTION

This study examined the femur geometry underlying previously observed decline in BMD of the contralateral hip in the year following hip fracture compared to non-fractured controls.

METHODS

Geometry was derived from dual-energy X-ray absorptiometry scan images using hip structural analysis from women in the third cohort of the Baltimore Hip Studies and from women in the Study of Osteoporotic Fractures. Change in BMD, section modulus (SM), cross-sectional area (CSA), outer diameter, and buckling ratio (BR) at the narrow neck (NN), intertrochanteric (IT), and shaft (S) regions of the hip were compared.

RESULTS

Wider bones and reduced CSA underlie the significantly lower BMD observed in women who fractured their hip resulting in more fragile bones expressed by a lower SM and higher BR. Compared to controls, these women experienced a significantly greater decline in CSA (-2.3% vs. -0.2%NN, -3.2% vs. -0.5%IT), SM (-2.1% vs. -0.2%NN, -3.9% vs. -0.6%IT), and BMD (-3.0% vs. -0.8%NN, -3.3% vs. -0.6%IT, -2.3% vs. -0.2%S) and a greater increase in BR (5.0% vs. 2.1%NN, 6.0% vs. 1.3%IT, 4.4% vs. 1.0%S) and shaft outer diameter (0.9% vs. 0.1%).

CONCLUSION

The contralateral femur continued to weaken during the year following fracture, potentially increasing the risk of a second fracture.

Successes achieved and challenges ahead in translating biomarkers into clinical applications

Biomarkers are important tools for identifying and stratifying diseases, predicting their progression and determining the effectiveness, safety, and doses of therapeutic interventions. This is important for common chronic diseases such as diabetic nephropathy, osteoporosis, and rheumatoid arthritis which affect large numbers of patients worldwide. This article summarizes the current knowledge of established and novel biomarkers for each of these diseases as presented at the 2008 AAPS/ACCP joint symposium "Success Achieved and Challenges Ahead in Translating Biomarkers into Clinical Applications," in Atlanta, Georgia. The advantages and disadvantages of various proteomic, metabolomic, genomic, and imaging biomarkers are discussed in relation to disease diagnosis and stratification, prognosis, drug development, and potential clinical applications. The use of biomarkers as a means to determine therapeutic interventions is also considered. In addition, we show that biomarkers may be useful for adapting therapies for individual needs by allowing the selection of patients who are most likely to respond or react adversely to a particular treatment. They may also be used to determine whether the development of a novel therapy is worth pursuing by informing crucial go/no go decisions around safety and efficacy. Indeed, regulatory bodies now suggest that effective integration of biomarkers into clinical drug development programs is likely to promote the development of novel therapeutics and more personalized medicine.

Modulation of the inflammatory response for enhanced bone tissue regeneration

Proinflammatory cytokines are infamous for their catabolic effects on tissues and joints in both inflammatory diseases and following the implantation of biomedical devices. However, recent studies indicate that many of these same molecules are critical for triggering tissue regeneration following injury. This review will discuss the role of inflammatory signals in regulating bone regeneration and the impact of both immunomodulatory and antiinflammatory pharmacologic agents on fracture healing, to demonstrate the importance of incorporating rational control of inflammation into the design of tissue engineering strategies.

Bone turnover markers are correlated with total skeletal uptake of 99mTc-methylene diphosphonate (99mTc-MDP)

Background

Skeletal uptake of ^99mTc labelled methylene diphosphonate (^99mTc-MDP) is used for producing images of pathological bone uptake due to its incorporation to the sites of active bone turnover. This study was done to validate bone turnover markers using total skeletal uptake (TSU) of ^99mTc-MDP.

Methods

22 postmenopausal women (52–80 years) volunteered to participate. Scintigraphy was performed by injecting 520 MBq of ^99mTc-MDP and taking whole body images after 3 minutes, and 5 hours. TSU was calculated from these two images by taking into account the urinary loss and soft tissue uptake. Bone turnover markers used were bone specific alkaline phosphatase (S-Bone ALP), three different assays for serum osteocalcin (OC), tartrate resistant acid phosphatase 5b (S-TRACP5b), serum C-terminal cross-linked telopeptides of type I collagen (S-CTX-I) and three assays for urinary osteocalcin (U-OC).

Results

The median TSU of ^99mTc-MDP was 23% of the administered activity. All bone turnover markers were significantly correlated with TSU with r-values from 0.52 (p = 0.013) to 0.90 (p < 0.001). The two resorption markers had numerically higher correlations (S-TRACP5b r = 0.90, S-CTX-I r = 0.80) than the formation markers (S-Total OC r = 0.72, S-Bone ALP r = 0.66), but the difference was not statistically significant. TSU did not correlate with age, weight, body mass index or bone mineral density.

Conclusion

In conclusion, bone turnover markers are strongly correlated with total skeletal uptake of ^99mTc-MDP. There were no significant differences in correlations for bone formation and resorption markers. This should be due to the coupling between formation and resorption.

Biochemical markers of bone turnover: potential use in the investigation and management of postmenopausal osteoporosis

INTRODUCTION

The aim was to analyse data on the use of biochemical bone turnover markers (BTM) in postmenopausal osteoporosis.

METHODS

We carried out a comparative analysis of the most important papers concerning BTM in postmenopausal osteoporosis that have been published recently.

RESULTS

The BTM levels are influenced by several factors. They are moderately correlated with BMD and subsequent bone loss. Increased levels of bone resorption markers are associated with a higher risk of fracture. Changes in the BTM during the anti-osteoporotic treatment (including combination therapy) reflect the mechanisms of action of the drugs and help to establish their effective doses. Changes in the BTM during the anti-resorptive treatment are correlated with their anti-fracture efficacy.

CONCLUSION

Biological samples should be obtained in a standardised way. BTM cannot be used for prediction of the accelerated bone loss at the level of the individual. BTM help to detect postmenopausal women who are at high risk of fracture; however, adequate practical guidelines are lacking. BTM measurements taken during the anti-resorptive therapy help to identify non-compliers. They may improve adherence to the anti-resorptive therapy and the fall in the BTM levels that exceeds the predefined threshold improves patients' persistence with the treatment. There are no guidelines concerning the use of BTM in monitoring anti-osteoporotic therapy in postmenopausal women.

Serial assessment of serum bone metabolism markers identifies women with the highest rate of bone loss and osteoporosis risk

CONTEXT

One of the important challenges in the management of osteoporosis is to identify women who are at high risk of developing osteoporosis and fragility fractures.

OBJECTIVE

Our objective was to evaluate whether assessment of bone metabolism at multiple occasions can identify women with the highest risk for bone loss.

DESIGN

The Malmö Osteoporosis Prospective Risk Assessment study is an ongoing longitudinal study. Participants have been evaluated at baseline and after 1, 3, and 5 yr.

SETTING

We conducted a population-based study.

PARTICIPANTS

Participants included 1044 women, all 75 yr old at baseline.

MAIN OUTCOME MEASURES

Seven bone turnover markers were assessed at baseline and at 1, 3, and 5 yr (n = 573). The 5-yr change in areal bone mineral density (aBMD) was also determined.

RESULTS

Baseline markers correlated weakly to change in total body aBMD. The associations were more pronounced when the average of the baseline and 1-yr measurements was used (standardized regression coefficients -0.12 to -0.23, P < 0.01). Adding the 3-yr and 5-yr measurement further strengthened the correlation (regression coefficients up to -0.30, P < 0.001). Women with constantly high turnover lost significantly more bone at total body assessment (-2.6%) than women with intermediate (-1.6%) or low turnover (-0.2%, P for trend < 0.001). They also had a greater decrease in hip BMD (-8.3, -6.0, and -5.1%, respectively, P = 0.010). Results were similar also in the subgroup of women with osteopenia.

CONCLUSIONS

Our results suggest that serial assessment of bone turnover improves the identification of women with the highest rate of bone loss and osteoporosis risk.

Synthetic bone grafts, the role of the gypsum in bone substitution; molecular biological approach

A csontpótlást igénylő műtéti beavatkozások során a beültetésre kerülő csontpótló graft tulajdonságai meghatározzák az eljárás kimenetelét, rövid és hosszú távú sikerét. Munkánk első részében áttekintést adunk a modern csontpótló eljárások előnyeiről-hátrányairól, illetve részletesen foglalkozunk a gipsz szintetikus csontpótló graftként történő alkalmazásának lehetőségével. A kísérletes klinikai leírások biztonsággal és jó hosszú távú eredménnyel alkalmazható csonthiánykitöltő anyagként írják le a kalcium-szulfát-dihidrátot, azonban a gipsz csontsejtekre kifejtett hatása, a csontpótlás mechanizmusa nem ismert. Molekuláris biológiai módszerekkel vizsgáltuk a gipsz csontsejtekre gyakorolt hatását. Az egér-praeosteoblastok szaporodására ideális tenyésztőfelületnek bizonyult a gipsz, míg a klinikumban gyakran csonthiánykitöltő anyagként alkalmazott polimetil-metakrilát-csontcement gátolta a sejtek osztódását. A gipsz megváltoztatta a sejtek génkifejeződési profilját, a csontképződés irányába mutató gének expresszálódtak nagyobb mértékben a gipszes tenyészetekben, és ezekben a sejtkultúrákban emelkedett alkalikusfoszfatáz-aktivitást mértünk. Eredményeink molekuláris biológiai szempontból támasztották alá a gipsz szintetikus csontpótló graftként történő alkalmazásának létjogosultságát, a kalcium-szulfát-dihidrát új – a csontgyógyulást támogató – tulajdonságát is kimutatva.

Metabolic and endocrine abnormalities in patients with nonunions

OBJECTIVES

To determine whether patients with unexplained nonunions, patients with a history of multiple low-energy fractures with at least one progressing to a nonunion, and patients with a nonunion of a nondisplaced pubic rami or sacral ala fracture would have an underlying metabolic or endocrine abnormality that had not been previously diagnosed.

DESIGN

Case series.

SETTING

Tertiary referral center.

PATIENTS AND INTERVENTION

From a larger series of 683 consecutive patients with nonunion seen by us between January 1998 and December 2005, 37 patients were referred to 1 of 2 clinically practicing endocrinologists to undergo an evaluation for metabolic and endocrine abnormalities. The screening criteria were: 1) an unexplained nonunion that occurred despite adequate reduction and stabilization (and debridement in initially infected cases) without obvious technical error and without any other obvious etiology; 2) a history of multiple low-energy fractures with at least one progressing to a nonunion; or 3) a nonunion of a nondisplaced pubic rami or sacral ala fracture.

RESULTS

In all, 31 of the 37 patients (83.8%, 95% CI: 71.3% to 93.8%) who met our screening criteria had one or more new diagnoses of metabolic or endocrine abnormalities. The most common newly diagnosed abnormality was vitamin D deficiency (25 of 37 patients; 68%). Other newly diagnosed abnormalities included calcium imbalances, central hypogonadism, thyroid disorders, and parathyroid hormone disorders. All newly diagnosed abnormalities were treated medically. Eight patients who underwent no operative intervention following the diagnosis and treatment of a new metabolic or endocrine abnormality achieved bony union in an average of 7.6 months (range, 3 to 12 months) following their first visit to the endocrinologist.

CONCLUSIONS

Although our study does not prove a causal link between metabolic and endocrine abnormalities and either the development or healing of nonunions, 84% of the patients who met our screening criteria were found to have metabolic or endocrine abnormalities, and eight of our patients achieved bony union following medical treatment alone. All patients with nonunion who meet our screening criteria should be referred to an endocrinologist for evaluation because they are likely to have undiagnosed metabolic or endocrine abnormalities that may be interfering with bone healing.

Prediction of bone loss using biochemical markers of bone turnover

The association between baseline levels of eleven bone turnover markers and 5-year rate of bone density change was prospectively studied in a population-based sample of 601 75-year-old women. Several bone formation and resorption markers as well as urinary osteocalcin were modestly correlated to rate of bone density change.

INTRODUCTION

Prediction of bone loss by bone turnover markers (BTMs) has been investigated with conflicting results. There is limited information in the elderly.

METHODS

Eleven bone turnover markers were analyzed in 75-year old women in the OPRA study (n = 601) and compared to the 5-year change of areal bone mineral density (aBMD) in seven skeletal regions.

RESULTS

Annual aBMD change varied between +0.4% (spine) and -2.0% (femoral neck). Significant associations (p < 0.01) were found for four different serum osteocalcins (S-OCs) (standardized regression coefficient -0.20 to -0.22), urinary deoxypyridinoline (-0.19), serum TRACP5b (-0.19), serum CTX-I (-0.21), two of the three urinary osteocalcins (U-OCs) (-0.16) and aBMD change of the leg region (derived from the total body measurement). After adjustment for baseline aBMD, associations were found for all S-OCs (-0.11 to -0.16), two of the three U-OCs (-0.14 to -0.16) and aBMD change at the total hip, and for three of the four S-OCs (-0.14 to -0.15), S-TRACP5b (-0.11), two of the three U-OCs (-0.14 to -0.15) and aBMD change at the femoral neck. There were no significant results concerning aBMD change at the spine.

CONCLUSION

This study indicates that BTMs are correlated with aBMD loss in some skeletal regions in elderly women.

Effect of fracture on bone turnover markers: a longitudinal study comparing marker levels before and after injury in 113 elderly women

In this longitudinal, prospective, and population-based study (n = 1044), seven BTMs were assessed before and after trauma in 113 elderly women (85 with fractures). Markers were not altered in the immediate postfracture period but were clearly elevated during fracture repair. Recent fracture should thus be taken into account when markers are used in clinical practice.

INTRODUCTION

Fracture may influence the levels of bone turnover markers (BTM) and have implications for their use in clinical practice. In this longitudinal, prospective, and population-based study, we assessed prefracture levels of BTMs and compared them with postfracture levels of the same individuals immediately after fracture and during fracture repair. This is the first study in which the effect of fracture on bone markers has been evaluated with prefracture samples available.

MATERIALS AND METHODS

Serum and urine were collected at the emergency unit from 85 women (77.9 +/- 1.8 yr) who sustained a fracture after low-energy trauma and 28 controls (77.8 +/- 2.0 yr) with similar trauma but no fracture. All were participants of the Malmö OPRA study (n = 1044), and pretrauma samples were collected 1.05 +/- 0.85 yr before. Bone turnover was assessed by seven different BTMs reflecting different stages of bone metabolism {C-terminal cross-linked telopeptides of type I collagen [S-CTX], S-TRACP5b, N-terminal propeptides of type I collagen [S-PINP], serum osteocalcin (S-OC[1-49] and S-TotalOC), urinary deoxypyridinoline [U-DPD], and urinary osteocalcin [U-OC]}.

RESULTS

BTMs sampled within a few hours after fracture were not altered from preinjury levels. Both bone formation and bone resorption markers were, however, significantly increased 4 mo after fracture. The elevation was most pronounced after hip fracture. Bone turnover remained elevated up to 12 mo after fracture.

CONCLUSIONS

We believe this study extends our knowledge on the skeletal postfracture metabolic processes. In addition, it may provide a basis for future means to monitor pharmacological intervention promoting fracture healing.

Effect of gypsum on proliferation and differentiation of MC3T3-E1 mouse osteoblastic cells

Recently, calcium sulfate dihydrate has been demonstrated as safe biodegradable osteoconductive bone void filler. However, its exact mechanism of action on bone cells is yet unknown. In this study, the influence of gypsum on gene expression and proliferation of MC3T3-E1 mouse pre-osteoblastic cells was investigated. Cells were cultured on gypsum disc, slice, polymethylmethacrylate (PMMA), or plastic culture plate for 15 days. Cell viability, alkaline phosphatase (ALP) activity and expression profile of 15 genes involved in bone metabolism were measured in cultures. Cell proliferation on gypsum was increased by almost 2-fold, while an inhibitory effect of PMMA on proliferation rate of osteoblasts was noted. Cells cultured on gypsum disc surface exhibited an increased ALP activity and markedly different gene expression profile. Quantitative real-time PCR data indicated the expression of genes that might provide a basis for an osteoinductive potential. MC3T3-E1 cells expressed genes typical of bone fracture healing like type II collagen and fibronectin 1. These effects might be related to the calcium content of gypsum and mediated likely via SMAD3. Our results suggest that gypsum can support new bone formation by its calcium content and modulatory effect on gene expression profile of bone cells.

Associations between homocysteine, bone turnover, BMD, mortality, and fracture risk in elderly women

Homocysteine has been suggested to be a risk factor for fracture, but the causal relationship is not clear. In 996 women from the OPRA study, high homocysteine level was associated with high bone marker levels and low BMD at baseline. During a mean 7-year follow-up, high homocysteine level was associated with mortality, but no clear association to fracture risk existed.

INTRODUCTION

Recently, the association between high serum homocysteine (Hcy) levels and an increased risk of fracture has been described.

MATERIALS AND METHODS

Hcy levels were measured at baseline in 996 women, all 75 years old. Vitamin B(12), folate, serum cross-linking telopeptide of type I collagen (CTX), serum TRACP5b, serum osteocalcin, urine deoxypyridinoline, PTH, areal BMD (aBMD), calcaneal quantitative ultrasound (QUS), and physical performance were assessed at baseline. Fractures and mortality were recorded during a mean follow-up of 7.0 years.

RESULTS

Bone marker levels were higher in women with Hcy in the highest quartile compared with all other women (p < 0.05). The most evident correlation between Hcy and a bone marker was seen with CTX (r = 0.19, p < 0.001). aBMD (hip) was 4% lower, QUS was up to 2% lower, and gait speed was 11% slower among women with Hcy in the highest quartile compared with the other women (p < 0.05). During the follow-up, 267 women sustained at least one low-energy fracture (including 69 hip fractures). When women in the highest Hcy quartile were compared with all other women, the hazard ratios (HRs) for sustaining any type of fracture was 1.18 (95% CI, 0.89-1.36) and for hip fracture was 1.50 (95% CI, 0.91-1.94). For the same group of women, the mortality risk was 2.16 (95% CI, 1.58-2.55). Adjustments for confounders did not substantially change these associations. Adjustment for PTH increased the HR for hip fracture to 1.67 (95% CI, 1.01-2.17). Low vitamin B(12) or folate was not associated with increased fracture risk or mortality.

CONCLUSIONS

High Hcy levels were associated with higher bone turnover, poor physical performance, and lower BMD. There was no clear association to fracture risk. The increased mortality among women with high Hcy levels indicates that a high Hcy level may be a marker of frailty.

Changes in Biochemical Markers after Lower Limb Fractures

Background: The bone remodeling sequence after bone fracture changes the concentrations of biochemical bone markers, but the relationships of fracture size and of healing time to changes in biomarkers are unclear. The present pilot study was undertaken to determine the changes found in serum bone markers after plate osteosynthesis of closed distal tibial and malleolar fractures during a study period of 24 weeks.

Methods: We measured tatrate-resistant acid phosphatase (TRACP 5b), collagen type I C-terminal telopeptide (ICTP), bone-specific alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen type I C-terminal propeptide (PICP), procollagen type III N-terminal propeptide (PIIINP), and human cartilage glycoprotein 39 (YKL-40) in 20 patients with lower limb fractures (10 malleolar, 10 tibia). A physical examination and radiographs were completed to assess evidence of union.

Results: All malleolar fractures healed within 6 weeks, whereas 2 tibial fractures did not show complete bone healing after 24 weeks. Changes were comparable but more pronounced in the tibia group, and marker concentrations remained increased at the end of study (bone ALP, 86 vs 74 U/L; OC, 14.9 vs 7.7 μg/L; ICTP: 5.6 vs 3.3 μg/L at day 84 after osteosynthesis, P &lt;0.05 in tibia; 80 vs 70 U/L, 8 vs 5.2 μg/L, and 3.5 vs 3.2 μg/L, respectively, in the malleolar fracture group).

Conclusions: In normal bone healing, changes in bone turnover markers were primarily dependent on the fracture size. Delayed tibia fracture healing may involve a disturbance in bone remodeling.