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

Association between bone turnover markers and FRAX predicted fracture risk in Chinese adults: a cross-sectional study

OBJECTIVE

Our study investigated the associations between bone turnover markers (BTMs) and bone mineral density (BMD) and fracture risk over the next 10 years. The objective of the study was to evaluate the potential effects of BTMs in fracture risk.

METHODS

Our cross-sectional study enrolled 580 participants (380 postmenopausal women and 200 men over the age of 50). All participants completed a questionnaire and dual-energy X-ray absorptiometry examination. We obtained BMD values for the lumbar spine, femoral neck, and total hip joint and biochemical indicators such as creatinine, type 1 procollagen N-terminal propeptide (P1NP), and beta cross-linked C-telopeptide of type 1 collagen (β-CTX). Furthermore, we used an online fracture risk assessment tool (FRAX) to calculate the probability of major osteoporotic fractures (PMOF) and hip fractures (PHF) over the next 10 years. We divided the participants into three groups based on the BMD T-score criteria: normal bone mass group (T-score ≥ - 1.0 SD), osteopenic group (- 2.5 SD < T-score < - 1.0 SD), and osteoporotic group (T-score ≤ - 2.5 SD). We compared differences in BTMs, BMD, and fracture risks among the three groups. Additionally, we evaluated differences in indicators between males and females and explored risk factors associated with BMD and fracture risk.

RESULTS

Postmenopausal women showed higher bone turnover markers, osteoporosis prevalence, and fracture risks compared to men. In a multivariate stepwise regression analysis, we identified P1NP was positively correlated with fracture risk for both PMOF (β = 0.087, p = 0.005) and PHF (β = 0.135, p < 0.001) over the next 10 years. In the logistic regression analysis, after adjusting for sex, we found that for every standard deviation increase in P1NP, the future 10-year risk of fractures increased by approximately 5.2-fold in the high PMOF group and 5.6-fold in the high PHF group.

CONCLUSION

Our study demonstrated that elevated serum P1NP levels were associated with increased fracture risk over a 10-year period. These findings suggested that serum P1NP measurement could be a valuable complementary tool alongside BMD measurements and FRAX assessments for identifying individuals at high risk of fracture.

Effect of vitamin B1 supplementation on bone turnover markers in adults: an exploratory single-arm pilot study

Although B vitamins have been shown to play beneficial roles in bone health, the effects of vitamin B1 in humans are still unclear. This study aimed to investigate the effects of vitamin B1 supplementation on middle-aged and older adults. This single-armed trial study included community-dwelling adults in Japan and used a pre- and post-test design. The participants were given 28.0 mg of vitamin B1 supplementation per day for 1 month in addition to their daily usual diet. The effect of this treatment on bone turnover markers and metabolism was evaluated at baseline and after 1 month. Forty-two participants were enrolled (mean age, 58.6 ± 10.4 years; 36 women). The vitamin B1 levels in whole blood increased significantly from baseline after vitamin B1 supplementation. The level of serum tartrate-resistant acid phosphatase 5b (TRACP 5b), a bone resorption marker, reduced significantly (378 ± 135 vs. 335 ± 120 mU/dL, p < 0.001), while the level of N-terminal propeptide of type I procollagen (P1NP), a marker specific to bone formation, did not change. Moreover, the serum phosphorus and parathyroid hormone (PTH) concentrations did not change, whereas the corrected serum calcium concentrations increased and vitamin D concentrations decreased. The serum TRACP 5b levels decreased after vitamin B1 supplementation in the middle-aged and older adults. Further definitive trials are needed to determine the efficacy of vitamin B1 in improving bone health.

Reference Intervals (RIs) of the Bone Turnover Markers (BTMs) in Children and Adolescents: A Proposal for Effective Use

BACKGROUND/OBJECTIVES

Bone turnover markers (BTMs) can provide information on the bone growth of apparently healthy children and adolescents or useful results in the diagnosis and monitoring of the disease condition, comparing them with appropriate reference intervals (RIs). The aim of this study was to establish the RI for the BTM [specific bone alkaline phosphatase (BALP), carboxy-terminal cross-linked collagen type I telopeptide (CTX), N-terminal propeptide pro-collagen type I (PINP), osteocalcin (OC), resistant to acid tartrate phosphatase isoform 5b (TRAcP-5b)] on serum samples from children and adolescents.

METHOD

202 samples from children and adolescents (ages 1-18 years) (51.48% male), considered apparently healthy. The biomarker was analyzed on automatic immunometric equipment (TGSTA Technogenetics) and the IDS-iSYS automated system kits The RI of the studied parameters was calculated according to CLSI Guideline C28-A3 with stratification by age and sex. Evaluation of the distribution of values and the meaning of the biomarker concentrations were used to calculate general and specific RI for an age group.

RESULTS

BTM concentrations vary with pubertal growth. The pattern of change differs for each bone marker. General and age-specific RI were calculated: 1-14 years, 15-18 years for BALP and CTX; 1-13 years, 14-18 years for Oc and PINP and 1-12 years, 13-18 years for TRAcP.

DISCUSSION AND CONCLUSIONS

Concentrations for biomarker studied vary with age and gender. The proof of concentrations with insignificant changes until puberty led to identification of two groups of RI relating to the covariables (age and sex) for each biomarker.

Correlation Between Bone Metabolism Indices and Osteoporotic Thoracolumbar Vertebrae Fracture in Postmenopausal Women

Background

This study aims to explore the correlation between bone metabolism indices and osteoporotic thoracolumbar vertebrae fracture (OTVF) in postmenopausal women.

Methods

A total of 447 female patients with postmenopause and underwent OTVF in our hospital were selected as group A. Three hundred eighty-seven out-patients without fractures were selected as group B. Bone metabolism index including the serum levels of total Serum procollagen type N-terminal propeptide (tPINP), the age-related type I cross linked C-telopeptide (β-CTX) and 25-hydroxyvitamin D (25-OHD) were collected and compared. The relation between bone metabolism indices and OTVF was analyzed.

Results

The mean tPINP in group A was 61.72 ± 28.43, which was notably higher than group B (P < 0.01). Meanwhile, greater β-CTX were higher founded in group A than group B (0.778 ± 0.316 vs 0.669 ± 0.303 μg/l). However, the 25-OHD in group A was significantly lower than that in group B (P < 0.05). Multivariate logistic regression analysis revealed that the serum level of tPINP (OR: 0.008, P = 0.011), the serum level of β-CTX (OR: 0.805, P = 0.002) and the serum level of 25-OHD (OR: -0.029, P = 0.003) were independently correlated with postmenopausal OTVF.

Conclusion

Bone metabolic markers play an important role in predicting OTVF. As a reflection of bone mass and bone strength, BMD is inadequate in predicting OTVF. High expression of bone metabolism indicators β-CTX, tPINP and relatively low expression of 25-OHD suggest an increased risk of OTVF. Early detection of postmenopausal bone metabolism abnormalities can be used for early intervention to reduce the incidence of OTVF.

Amorphous Calcium Carbonate Enhances Fracture Healing in a Rat Fracture Model

Background: Delayed and failed fracture repair and bone healing remain significant public health issues. Dietary supplements serve as a safe, inexpensive, and non-surgical means to aid in different stages of fracture repair. Studies have shown that amorphous calcium carbonate (ACC) is absorbed 2 to 4.6 times more than crystalline calcium carbonate in humans. Objectives: In the present study, we assessed the efficacy of ACC on femoral fracture healing in a male Wistar rat model. Methods: Eighty male Wistar rats were randomly divided into five groups (n = six per group): sham, fracture + water, fracture + 0.5× (206 mg/kg) ACC, fracture + 1× ACC (412 mg/kg), and fracture + 1.5× (618 mg/kg) ACC, where ACC refers to the equivalent supplemental dose of ACC for humans. A 21-gauge needle was placed in the left femoral shaft, and we then waited for three weeks. After three weeks, the sham group of rats was left without fractures, while the remaining animals had their left mid-femur fractured with an impactor, followed by treatment with different doses of oral ACC for three weeks. Weight-bearing capacity, microcomputed tomography, and serum biomarkers were evaluated weekly. After three weeks, the rats were sacrificed, and their femur bones were isolated to conduct an evaluation of biomechanical strength and histological analysis. Results: Weight-bearing tests showed that treatment with ACC at all the tested doses led to a significant increase in weight-bearing capacity compared to the controls. In addition, microcomputed tomography and histological studies revealed that ACC treatment improved callus formation dose-dependently. Moreover, biomechanical strength was improved in a dose-dependent fashion in ACC-treated rats compared to the controls. In addition, supplementation with ACC significantly lowered bone formation and resorption marker levels two-three weeks post-fracture induction, indicating accelerated fracture recovery. Conclusions: Our preliminary data demonstrate that ACC supplementation improves fracture healing, with ACC-supplemented rats healing in a shorter time than control rats.

Effects of Erythropoietin-Promoted Fracture Healing on Bone Turnover Markers in Cats

In orthopaedics, erythropoietin (EPO) is applied in the preoperative management of anaemic patients, but also as a stimulating factor to assist bone regeneration due to its angiogenic and osteoinductive potential. Since orthopaedists mainly rely on their clinical experience to assess bone healing, additional and more objective methods such as studying the dynamics of bone markers are needed. Therefore, the aim of this study was to investigate the plasma activity of bone-specific alkaline phosphatase (BALP), the N-terminal propeptide of type I collagen (PINP), the C-terminal telopeptide of type I collagen (CTX), and deoxypyridinoline (DPD) during the first 2 months of healing of comminuted fractures in cats, either non-stimulated or locally stimulated with recombinant human erythropoietin (rhEPO). The study included twelve cats of mixed breeds, aged 7.2 ± 4 months, weighing 2.11 ± 1.1 kg, with comminuted diaphyseal fractures of the femur. Surgical treatment with plate osteosynthesis was performed in all animals. The cats were randomly divided into two groups-a control (n = 6) and an EPO group (n = 6). The locally applied EPO leads to the increased activity of bone formation markers (BALP and PINP) during the second week after the osteosynthesis, preceding the peaks in the control group by two weeks. The studied bone resorption markers (DPD, CTX) varied insignificantly during the studied period. In conclusion, erythropoietin could serve as a promoter of bone healing in comminuted fractures in cats.

Surgical outcomes of anterior column reconstruction for spinal fractures caused by minor trauma-preoperative examination of the number of intervertebral bone bridges is key to obtaining good bone fusion

BACKGROUND

To achieve good bone fusion in anterior column reconstruction for vertebral fractures, not only bone mineral density (BMD) and bone metabolism markers but also lever arms due to bone bridging between vertebral bodies should be evaluated. However, until now, no lever arm index has been devised. Therefore, we believe that the maximum number of vertebral bodies that are bony and cross-linked with the contiguous adjacent vertebrae (maxVB) can be used as a measure for lever arms. The purpose of this study is to investigate the surgical outcomes of anterior column reconstruction for spinal fractures and to determine the effect of bone bridging between vertebral bodies on the rate of bone fusion using the maxVB as an indicator of the length of the lever arm.

METHODS

The clinical data of 81 patients who underwent anterior column reconstruction for spinal fracture between 2014 and 2022 were evaluated. The bone fusion rate, back pain score, between the maxVB = 0 and the maxVB ≥ 2 patients were adjusted for confounding factors (age, smoking history, diabetes mellitus history, BMD, osteoporosis drugs, surgical technique, number of fixed vertebrae, materials used for the anterior props, etc.) and analysed with multivariate or multiple regression analyses. The bone healing rate and incidence of postoperative back pain were compared among the three groups (maxVB = 0, 2≦maxVB≦8, maxVB ≧ 9) and divided by the maxVB after adjusting for confounding factors.

RESULTS

Patients with a maxVB ≥ 2 had a significantly higher bone fusion rate (p < 0.01) and postoperative back pain score (p < 0.01) than those with a maxVB = 0. Among the three groups, the bone fusion rate and back pain score were significantly higher in the 2≦maxVB≦8 group (p = 0.01, p < 0.01).

CONCLUSIONS

Examination of the maxVB as an indicator of the use of a lever arm is beneficial for anterior column reconstruction for vertebral fractures. Patients with no intervertebral bone bridging or a high number of bone bridges are in more need of measures to promote bone fusion than patients with a moderate number of bone bridges are.

Association between blood markers and the progression of osseointegration in percutaneous prostheses patients-A pilot study

Patients implanted with osseointegrated (OI) prosthetic systems have reported vastly improved upper and lower extremity prosthetic function compared with their previous experience with socket-suspension systems. However, OI systems have been associated with superficial and deep-bone infections and implant loosening due, in part, to a failure of the osseointegration process. Although monitoring the osseointegration using circulating biomarkers has clinical relevance for understanding the progression of osseointegration with these devices, it has yet to be established. Ten patients were enrolled in this study. Blood samples were collected at pre-selected times, starting before implantation surgery, and continuing to 12 months after the second surgery. Bone formation markers, bone resorption markers, and circulating amino acids were measured from blood samples. A linear mixed model was generated for each marker, incorporating patient ID and age with the normalized marker value as the response variable. Post hoc comparisons were made between 1 week before Stage 1 Surgery and all subsequent time points for each marker, followed by multiple testing corrections. Serial radiographic imaging of the residual limb containing the implant was obtained during follow-up, and the cortical index (CI) was calculated for the bone at the porous region of the device. Two markers of bone formation, specifically bone-specific alkaline phosphatase (Bone-ALP) and amino-terminal propeptide of type I procollagen (PINP), exhibited significant increases when compared with the baseline levels of unloaded residual bone prior to the initial surgery, and they subsequently returned to their baseline levels by the 12-month mark. Patients who experienced clinically robust osseointegration experienced increased cortical bone thickness at the porous coated region of the device. A medium correlation was observed between Bone-ALP and the porous CI values up to PoS2-M1 (p = .056), while no correlation was observed for PINP. An increase in bone formation markers and the lack of change observed in bone resorption markers likely reflect increased cortical bone formation induced by the end-loading design of the Utah OI device used in this study. A more extensive study is required to validate the correlation observed between Bone-ALP and porous CI values.

Serum Markers of Bone Turnover Following Controlled Administration of Two Medical Cannabis Products in Healthy Adults

Introduction: Cannabidiol (CBD) has been shown to maintain bone integrity in pre-clinical models, but little is known about the effects of delta-9-tetrahydrocannabinol (THC) on bone turnover. In this study we explored the effects of two oral medical cannabis products on normal bone homeostasis through evaluation of markers of bone resorption (carboxyl-terminal collagen crosslinks, CTx) and bone formation (procollagen type 1 N-terminal propeptide, P1NP; alkaline phosphatase, ALP). Methods: This study is an analysis of secondary data from two Phase 1 double-blind, placebo-controlled trials of Spectrum Yellow (0.9 mg THC, 20 mg CBD/mL of oil) and Spectrum Red (2.5 mg THC, 0.3 mg CBD/softgel). Healthy participants (n=38 men, 45 women) were randomized to receive 5-20 mg THC (CBD levels varied as a function of administered product) or placebo daily (BID) for 7 days. Bone markers were assessed at baseline, upon completion of product administration (day 8), and after a 5-day washout (day 13). Results: All bone markers were significantly higher in men at baseline (p≤0.008). For CTx, there was a significant day×group interaction (F=3.23, p=0.04); CTx levels were significantly lower in participants treated with Spectrum Red (b=-164.28; 95% confidence interval [CI], -328 to -0.29; p=0.04) and marginally lower in participants treated with Spectrum Yellow (b=-157.31; 95% CI, -323 to 8.68; p=0.06) versus placebo on day 8. For P1NP and ALP, there were no significant differences between treatments across study days. Bone marker values outside the reference range (RR) were observed; CTx > RR (n=71) was predominantly (85.9%) observed in male participants, whereas P1NP > RR (n=100) was more evenly distributed between sexes (53.0% in men). These were not considered clinically significant and did not differ between treatment groups. Conclusions: These are the first interventional human data on the effect of cannabinoids on biomarkers of bone turnover. Short-term treatment with CBD- or THC-dominant medical cannabis products resulted in attenuation of a marker of bone resorption. Although the attenuation was not clinically significant, this finding may be indicative of protective properties of cannabinoids in bone. Further research over longer dosing durations in individuals exhibiting bone-specific conditions (e.g., osteoporosis) is warranted. ClinicalTrials.gov IDs: ACTRN12619001723178 and ACTRN12619001450101.

Serum levels of bone turnover markers including calculation of Z-scores: Data from a Dutch healthy reference cohort

Introduction

Bone turnover markers (BTM) are biochemical compounds reflecting different stages of bone metabolism. Their levels change with age and differ between males and females. This makes clinical interpretation and comparison more difficult. Therefore, our aim was to establish BTM reference values which can be used to calculate Z-scores for use in daily clinical practice.

Methods

Serum markers of collagen resorption, bone formation/regulation, collagen formation and bone mineralization (sCTX, OC, PINP and BALP, respectively) were measured in non-fasting volunteers without bone-related abnormalities. Raw data was plotted and gender-specific age cohorts were established with their respective means and standard deviations (SD). Z-scores can be calculated using these reference values to correct for the influence of age and gender on BTM.

Results

In total, 856 individuals were included of which 486 (57 %) were female. Individuals were aged between 7 and 70 years. Highest serum levels of BTM were found in childhood and puberty. Peak levels are higher in boys than girls and prevail at later ages. In adults, BTM levels decrease before reaching stable nadir levels. In adults, 10-year reference cohorts with means and SD were provided to calculate Z-scores.

Conclusion

With our data, Z-scores of sCTX, OC, PINP and BALP can be calculated using reference categories (for age and gender) of Caucasian healthy volunteers. Clinicians can use BTM Z-scores to determine whether there are changes in bone turnover physiology beyond those expected during aging. BTM Z-scores facilitate harmonization of data interpretation in daily clinical practice and research.

Bone turnover biomarkers predict one-year all-cause mortality and walking ability in geriatric hip fracture patients

PURPOSE

To investigate the utility of serum C-terminal cross-linking telopeptides (β-CTX) and procollagen type I N propeptide (PINP) for predicting one-year mortality and walking ability in Chinese geriatric hip fracture patients who underwent surgical interventions.

METHOD

Elderly patients (≥ 60 years) who underwent surgical interventions for unilateral low-energy hip fracture from 2015 to 2020 in our center were included. Demographic data was retrospectively retrieved from the electronic medical database. The PINP and β-CTX concentrations were measured before the surgery. The patients were divided into two groups according to the outcome of mortality and walking ability after hip surgery, respectively. β-CTX and PINP were divided into four grades based on quartiles [Quartile(Q)1-4] for further analysis. All the variables with p < 0.1 in univariable analysis were included in a multivariable model.

RESULTS

In univariable analysis, the levels of serum β-CTX (p = 0.007) and PINP (p = 0.025) was associated with one-year mortality, while the association between levels of serum β-CTX (p = 0.072) or PINP (p = 0.055) with one-year disability was marginally significant. After adjustment for confounders, the relative risk [OR (95 % CI), Q4 v sQ1, p-value] of one-year mortality and one-year disability were 7.28 (2.08-29.78, p = 0.003) and 3.97 (1.44-11.69, p = 0.009) for β-CTX and 5.87 (1.70-23.80, p = 0.008) and 3.48 (1.30-9.93, p = 0.016) for PINP, respectively. The coefficient of determination, AUC and bias-corrected C-index of predictive models based on previously reported predictors were significantly improved after integrating β-CTX or PINP.

CONCLUSION

Higher serum β-CTX and PINP are independently associated with an increased risk of one-year mortality and disability in patients with hip fractures. The application of BTMs improves the performance of currently available predictive models.

Number of contiguous vertebral cross-links in the spine indicates bone formation: a cross-sectional study

BACKGROUND

As an indicator to evaluate the risk of fracture in diffuse idiopathic skeletal hyperostosis, the maximum number of vertebral bodies' bone cross-linked with contiguous adjacent vertebrae (max VB) was developed. This study retrospectively investigates the relationship between max VB, bone mineral density (BMD), and bone metabolic markers (BMM).

METHODS

In this cross-sectional study (from April 2010 to January 2022), males (n = 114) with various max VB from the thoracic vertebra to the sacrum, measured using computed tomography scans, were selected to assess femur BMD and BMM. The association of max VB with the total type I procollagen N-terminal propeptide (P1NP), tartrate-resistant acid phosphatase 5b (TRACP-5b), and bone turnover ratio (BTR = TRACP-5b/P1NP) as well as its relationship with femur BMD with P1NP and TRACP-5b, were investigated. Furthermore, the relationship between P1NP and TRACP-5b was investigated.

RESULTS

P1NP increased in proportion to max VB and TRACP-5b increased in proportion to P1NP. Moreover, BTR was inversely proportional to max VB. Finally, femur BMD was inversely proportional to P1NP and TRACP-5b.

CONCLUSION

As max VB increased with P1NP-a potential osteogenesis indicator-and BTR was inversely proportional to max VB with compensatory TRACP-5b increase, max VB can be considered as a possible predictor of bone fusion.

Treatment of osteoporosis using a selective androgen receptor modulator ostarine in an orchiectomized rat model

PURPOSE

The selective androgen receptor modulator ostarine has been shown to have advantageous effects on skeletal tissue properties, reducing muscle wasting and improving physical function in males. However, data on effects in male osteoporosis remain limited. In this study, the effects of ostarine on osteoporotic bone were evaluated in a rat model of male osteoporosis and compared with those of testosterone treatments.

METHODS

Eight-month-old male Sprague-Dawley rats were either non-orchiectomized to serve as a healthy control (Non-Orx, Group 1) or orchiectomized (Orx, Groups 2-6) and then grouped (n = 15/group): (1) Non-Orx, (2) Orx, (3) Ostarine Therapy, (4) Testosterone Therapy, (5) Ostarine Prophylaxis and (6) Testosterone Prophylaxis. Prophylaxis treatments started directly after orchiectomy and continued for 18 weeks, whereas Therapy treatments were initiated 12 weeks after Orx. Ostarine and Testosterone were applied orally at daily doses of 0.4 and 50 mg/kg body weight, respectively. The lumbar vertebral bodies and femora were analyzed using biomechanical, micro-CT, ashing, and gene expression analyses.

RESULTS

Ostarine Prophylaxis showed positive effects in preventing osteoporotic changes in cortical and trabecular bone (femoral trabecular density: 26.01 ± 9.1% vs. 20.75 ± 1.2% in Orx and in L4: 16.3 ± 7.3% vs 11.8 ± 2.9% in Orx); biomechanical parameters were not affected; prostate weight was increased (0.62 ± 0.13 g vs 0.18 ± 0.07 g in Orx). Ostarine Therapy increased solely the cortical density of the femur (1.25 ± 0.03 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); other bone parameters remained unaffected. Testosteron Prophylaxis positively influenced cortical density in femur (1.24 ± 0.05 g/cm3 vs. 1.18 ± 0.04 g/cm3 in Orx); Test. Therapy did not change any bony parameters.

CONCLUSION

Ostarine Prophylaxis could be further investigated as a preventative treatment for male osteoporosis, but an androgenic effect on the prostate should be taken into consideration, and combination therapies with other anti-osteoporosis agents could be considered.

Effectiveness of Weekly Teriparatide Injection in Postmenopausal Patients with Hip Fractures

Background

Teriparatide is an effective anabolic agent used in the treatment of severe osteoporosis. In addition, it is also used to promote fracture healing. The purpose of this double-blind randomized controlled trial was to evaluate the influence of weekly teriparatide administration on bone formation in hip fracture patients.

Methods

The control group (n = 41) was composed of patients treated with normal saline other than teriparatide, and the teriparatide group (n = 51) consisted of patients who received weekly teriparatide. Bone turnover markers, C-terminal telopeptide (CTx) and osteocalcin (OC), were assessed through blood tests at the initial hospital visit and 3-month, 6-month, and 1-year follow-ups. Dual-energy X-ray absorptiometry was performed 5 days postoperatively and at 1-year postoperative follow-up. The degree of fracture union was evaluated by comparing the radiographic union scoring system for hips using Radiographic Union Score for Hip (RUSH) scores between the two groups at 3 months, 6 months, and 1 year after surgery.

Results

Evaluation of the rate of change in bone mineral density over 1 year showed that the lumber bone mineral density increased by more than 7% in the experimental group. The control group did not show a difference between the CTx and OC at 6 months, but the difference between the CTx and OC values was large at 6 months in the experimental group. The mean RUSH score was significantly different between the control group and the experimental group: 12.105 and 15.476, respectively (p = 0.004), at 3 months and 18.571 and 22.389, respectively, at 6 months (p = 0.006).

Conclusions

Weekly use of teriparatide improved fracture healing, bone formation, and clinical outcomes at 1 year after hip fracture surgery by the anabolic window effect.

Bone Turnover Markers in Children: From Laboratory Challenges to Clinical Interpretation

Bone turnover markers (BTMs) have been developed many years ago to study, in combination with imaging techniques, bone remodeling in adults. In children and adolescents, bone metabolism differs from adults since it implies both growth and bone remodeling, suggesting an age- and gender-dependent BTM concentration. Therefore, specific studies have evaluated BTMs in not only physiological but also pathological conditions. However, in pediatrics, the use of BTMs in clinical practice is still limited due to these many children-related specificities. This review will discuss about physiological levels of BTMs as well as their modifications under pathological conditions in children and adolescents. A focus is also given on analytical and clinical challenges that restrain BTM usefulness in pediatrics.

Advancement in the Treatment of Osteoporosis and the Effects on Bone Healing

Osteoporosis (OP) is a major global health concern, with aging being one of the most important risk factors. Osteoarthritis (OA) is also an age-related disorder. Patients with OP and/or OA may be treated surgically for fractures or when their quality of life is impaired. Poor bone quality due to OP can seriously complicate the stability of a bone fixation construct and/or surgical fracture treatment. This review summarizes the current knowledge on the pathophysiology of normal and osteoporotic bone healing, the effect of a bone fracture on bone turnover markers, the diagnosis of a low bone mineral density (BMD) before surgical intervention, and the effect of available anti-osteoporosis treatment. Interventions that improve bone health may enhance the probability of favorable surgical outcomes. Fracture healing and the treatment of atypical femoral fractures are also discussed.

Bone Turnover Markers: Basic Biology to Clinical Applications

Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide; and commonly used resorption markers serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen and tartrate resistant acid phosphatase type 5b. BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable components (e.g., age, gender, ethnicity) and controllable components, particularly relating to collection conditions (e.g., fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics; and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.

Changes in Bone Turnover Markers after Osteoporotic Vertebral Compression Fractures in Males and Females

Background. To explore the normal changes in bone turnover markers (BTMs) and the correlations between the different BTMs after osteoporotic vertebral compression fracture (OVCF). Meanwhile, we explored the related differences that exist between sexes. Methods. A total of 130 OVCF patients were retrospectively reviewed. Using IBM SPSS 19.0 statistical software, the differences in the levels of BTMs and clinical parameters between sexes were assessed using Student’s unpaired $t$ test, and one-way ANOVA was used for the comparison of the three groups of samples. The correlations between P1NP, CTX, and clinical factors were assessed using Pearson’s correlation coefficient. Results. P1NP was 52.15 ng/ml within two weeks in male patients, and the level increased to 96.33 ng/ml after 12 weeks; in female patients, the increase was not as obvious as in male patients. CTX in male patients reached as much as approximately twice the initial value after 12 weeks. However, the situation in female patients was diverse. CTX was 0.58 ng/ml within two weeks and increased to 0.61 ng/ml within 2-12 weeks after the onset of OVCF. Subsequently, CTX decreased suddenly after 12 weeks. The increase in P1NP levels within 2 weeks after OVCF was significantly correlated with the levels of osteocalcin (OC) and bone-specific alkaline phosphatase (BAP). Changes in CTX within 2 weeks after OVCF were considerably related to phosphorus, 25 hydroxyvitamin D (25-OHD), OC, and BAP. Conclusion. The levels of P1NP and CTX increased differently in males and females after OVCF. The levels of OC and BAP were correlated with the levels of P1NP and CTX within 2 weeks of OVCF.

Clinical utility of bone turnover markers in patients with chronic kidney disease

PURPOSE OF REVIEW

The burden of fractures is very high in patients with chronic kidney disease (CKD). It is increasingly recognized that knowledge of bone turnover is of paramount importance in guiding mineral metabolism and osteoporosis therapy in CKD. Bone histomorphometry is the gold standard to assess bone turnover, but is seldomly performed in clinical practice. Bone turnover markers (BTMs) may be the long awaited noninvasive diagnostic that may help to close the therapeutic gap in patients with advanced CKD presenting with bone fragility.

RECENT FINDINGS

Mounting evidence indicates that BTMs may be useful in skeletal and nonskeletal risk stratification, in guiding mineral metabolism and osteoporosis therapy, and in monitoring the therapeutic response.

SUMMARY

BTMs provide information that is complementary to other clinical tests. It may be envisioned that in the near future, the assessment of nonkidney cleared BTMs may become part of routine clinical evaluation and monitoring of bone health in CKD patients, integrated with clinical risk factors, imaging data and, eventually, bone histomorphometry. Panels of BTMs will likely be more informative than single markers, and the same might hold true for trends as opposed to single time point data.

Target Values and Daytime Variation of Bone Turnover Markers in Monitoring Osteoporosis Treatment after Fractures

The serum bone turnover markers (BTM) procollagen type 1 N‐terminal propeptide (P1NP) and C‐terminal cross‐linking telopeptide of type 1 collagen (CTX) are recommended for monitoring adherence and response of antiresorptive drugs (ARD). BTM are elevated about 1 year after fracture and therefore BTM target values are most convenient in ARD treatment follow‐up of fracture patients. In this prospective cohort study, we explored the cut‐off values of P1NP and CTX showing the best discriminating ability with respect to adherence and treatment effects, reflected in bone mineral density (BMD) changes. Furthermore, we explored the ability of BTM to predict subsequent fractures and BTM variation during daytime in patients using ARD or not. After a fragility fracture, 228 consenting patients (82.2% women) were evaluated for ARD indication and followed for a mean of 4.6 years (SD 0.5 years). BMD was measured at baseline and after 2 years. Serum BTM were measured after 1 or 2 years. The largest area under the curve (AUC) for discrimination of patients taking ARD or not was shown for P1NP <30 μg/L and CTX <0.25 μg/L. AUC for discrimination of patients with >2% gain in BMD (lumbar spine and total hip) was largest at cut‐off values for P1NP <30 μg/L and CTX <0.25 μg/L. Higher P1NP was associated with increased fracture risk in patients using ARD (hazard ratio [HR]_logP1NP = 15.0; 95% confidence interval [CI] 2.7–83.3), p = 0.002. P1NP and CTX were stable during daytime, except in those patients not taking ARD, where CTX decreased by 21% per hour during daytime. In conclusion, P1NP <30 μg/L and CTX <0.25 μg/L yield the best discrimination between patients taking and not taking ARD and the best prediction of BMD gains after 2 years. Furthermore, higher P1NP is associated with increased fracture risk in patients on ARD. BTM can be measured at any time during the day in patients on ARD. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Management of patients at very high risk of osteoporotic fractures through sequential treatments

Osteoporosis care has evolved markedly over the last 50 years, such that there are now an established clinical definition, validated methods of fracture risk assessment and a range of effective pharmacological agents. Currently, bone-forming (anabolic) agents, in many countries, are used in those patients who have continued to lose bone mineral density (BMD), patients with multiple subsequent fractures or those who have fractured despite treatment with antiresorptive agents. However, head-to-head data suggest that anabolic agents have greater rapidity and efficacy for fracture risk reduction than do antiresorptive therapies. The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) convened an expert working group to discuss the tools available to identify patients at high risk of fracture, review the evidence for the use of anabolic agents as the initial intervention in patients at highest risk of fracture and consider the sequence of therapy following their use. This position paper sets out the findings of the group and the consequent recommendations. The key conclusion is that the current evidence base supports an "anabolic first" approach in patients found to be at very high risk of fracture, followed by maintenance therapy using an antiresorptive agent, and with the subsequent need for antiosteoporosis therapy addressed over a lifetime horizon.

Bone turnover markers as surrogates of fracture healing after intramedullary fixation of tibia and femur fractures

Aims

Bone turnover markers (BTMs) follow distinct trends after fractures and limited evidence suggests differential levels in BTMs in patients with delayed healing. The effect of vitamin D, and other factors that influence BTMs and fracture healing, is important to elucidate the use of BTMs as surrogates of fracture healing. We sought to determine whether BTMs can be used as early markers of delayed fracture healing, and the effect of vitamin D on BTM response after fracture.

Methods

A total of 102 participants aged 18 to 50 years (median 28 years (interquartile range 23 to 35)), receiving an intramedullary nail for a tibial or femoral shaft fracture, were enrolled in a randomized controlled trial comparing vitamin D₃ supplementation to placebo. Serum C-terminal telopeptide of type I collagen (CTX; bone resorption marker) and N-terminal propeptide of type I procollagen (P1NP; bone formation marker) were measured at baseline, six weeks, and 12 weeks post-injury. Clinical and radiological fracture healing was assessed at three months.

Results

CTX and P1NP concentrations peaked at six weeks in all groups. Elevated six-week CTX and P1NP were associated with radiological healing at 12 weeks post-injury (odds ratio (OR) 10.5; 95% confidence interval 2.71 to 53.5, p = 0.002). We found no association between CTX or P1NP and functional healing. Baseline serum 25(OH)D showed a weak inverse relationship with P1NP (p = 0.036) and CTX (p = 0.221) at 12 weeks, but we observed no association between vitamin D supplementation and either BTM.

Conclusion

Given the association between six-week BTM concentrations and three-month radiological fracture healing, CTX and P1NP appear to be potential surrogate markers of fracture healing.

Cite this article: Bone Joint Res 2022;11(4):239–250.

Longitudinal Changes in Serum Markers of Bone Metabolism and Bone Material Strength in Premenopausal Women with Distal Radial Fracture

BACKGROUND

Markers of bone metabolism (MBM) play an important role in fracture evaluation, and changes have been associated with increased fracture risk. The purpose of the present study was to describe changes in MBM in premenopausal women with distal radial fractures.

METHODS

Premenopausal women with distal radial fractures (n = 34) and without fractures (controls) (n = 39) were recruited. Serum MBM in patients with distal radial fractures were obtained at the time of the initial presentation, 6 weeks, and 3, 6, and 12 months. MBM included 25(OH) vitamin D, PTH, osteocalcin, P1NP, BSAP, CTX, sclerostin, DKK1, periostin, and TRAP5b. Areal bone mineral density (aBMD) was assessed with dual x-ray absorptiometry, and the bone material strength index (BMSi) was assessed with microindentation.

RESULTS

Most MBM reached peak levels at 6 weeks after the injury, including osteocalcin (+17.7%), sclerostin (+23.5%), and DKK1 (12.6%). Sclerostin was lower (-27.4%) and DKK1 was higher (+22.2%) at 1 year after the fracture. CTX declined below baseline levels at 6 and 12 months, whereas TRAP5b, BSAP, and periostin did not significantly change. At 12 months, sclerostin was lower (p = 0.003) and DKK1 was higher (p = 0.03) in the distal radial fracture group than in the control group. Greater fracture severity was associated with greater increases in P1NP and BSAP. aBMD and BMSi were not associated with fracture.

CONCLUSIONS

Distal radial fractures caused increases in several MBM, which typically peaked at 6 weeks after injury and gradually decreased over 6 months. Sclerostin and DKK1 remained below and above baseline at 1 year, respectively. Increasing fracture severity resulted in larger changes in MBM. aBMD and BMSi did not discriminate between patients with distal radial fractures and controls. Continued efforts to identify markers of skeletal fragility in young women are warranted to mitigate future fracture risk.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

The Relationship Between Stress Fractures and Bone Turnover Markers Is Unclear in Athletic and Military Populations: A Critically Appraised Topic

Clinical Scenario: Having an indication of how bone is remodeling in response to training load could help identify athletes and military personnel at increased stress fracture (SFx) risk. Direct assessment of bone remodeling is impractical. Biochemical markers of bone turnover are used as an indirect measure of bone remodeling and have potential to inform prevention and treatment efforts. To date, the relationship between bone turnover markers and SFxs in athletes or military personnel remains unclear. Clinical Question: Are SFxs related to bone turnover markers in athletes and military personnel? Summary of Key Findings: Seven met eligibility criteria. In five studies, an association between SFxs and bone turnover markers existed. Clinical Bottom Line: The evidence supporting a relationship between SFxs and bone turnover markers in athletes and military personnel is mixed. While five of the seven studies reported some type of relationship, no studies prospectively measured bone turnover markers in a group of athletes or military personnel without an SFx or without SFx history and followed them over time to reassess bone turnover markers upon SFx occurrence. Strength of Clinical Recommendation: In accordance with the Strength of Recommendation Taxonomy, Grade C is the most appropriate strength of recommendation rating.

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 Metabolism in the Healing Process of Lumbar Interbody Fusion: Temporal Changes of Bone Turnover Markers

STUDY DESIGN

Prospective longitudinal study.

OBJECTIVE

The aim of this study was to evaluate temporal changes of bone turnover markers (BTMs) after lumbar spinal fusion in patients without osteoporosis.

SUMMARY OF BACKGROUND DATA

Radiological studies are the standard method to monitor bony fusion, but they do not allow a timely assessment of bone healing. BTMs react rapidly to changes in bone metabolism during fusion process and could be an additional tool to monitor this process.

METHODS

A total of 78 nonosteoporosis patients who had undergone one- or two-level transforaminal lumbar interbody fusion were included. Fusion status was assessed using computed tomography sagittal and coronal images. Serum levels of bone-specific alkaline phosphatase (BAP), procollagen type 1 amino-terminal propeptide (P1NP), and osteocalcin (OC) were measured to assess bone formation, and tartrate-resistant acid phosphatase 5b (TRACP-5b) was measured to assess bone resorption. Serum samples were obtained before surgery and at 1, 2, 4, 8, 13, 26, 39, and 52 weeks after surgery.

RESULTS

A solid fusion was achieved in 71 of 78 patients (91%), and seven patients resulted in pseudarthrosis. In the fusion group, the level of all BTMs once decreased at 1 postoperative week. Then, BAP and P1NP reached a peak at 4 weeks after surgery, and TRACP-5b and OC peaked at 8 weeks. Thereafter, the level of P1NP and TRACP-5b gradually got closer to the baseline over a year, and BAP kept high until 52 postoperative weeks. In the pseudarthrosis group, peak level of BTMs was significantly higher and the increased level of BAP and P1NP was kept until 52 weeks.

CONCLUSION

The present study demonstrated dynamics of BTMs after lumbar spinal fusion in patients without osteoporosis. These normal population data contribute as a baseline to evaluate the effect of osteogenic agents on bone metabolism after spinal fusion.Level of Evidence: 2.

Inadequate response to treatment reveals persistent osteoclast bone resorption in osteoporotic patients

Several drugs are able to reduce fracture risk in osteoporotic patients. Incident fractures occur despite good adherence to treatment. Inadequate response has been found related to high serum bone biomarkers of bone turnover. We here aimed to analyze bone microarchitecture and cellular profiles of inadequate responders. We retrospectively analyzed bone biopsies from patients with major fractures despite long-term treatment (inadequate responder [IR] n = 31) in comparison to patients with untreated osteoporosis (U-OP, n = 31) and controls without osteoporosis (Ctrl, n = 16). Bone samples were analyzed by histomorphometry and micro-computed tomography. Clinical and bone turnover markers and bone mineral density were assessed. As compared with U-OP patients, IRs were older (mean age 69.7 ± 8.8 vs 63.3 ± 9.3 years, p = 0.007) and had lower mean hip bone mineral density (0.685 ± 0.116 vs 0.786 ± 0.093 g/cm²), p = 0.019 and T-score (-2.3 ± 0.769 vs -1.6 ± 0.900, p = 0.032). BV/TV was lower for IRs than U-OP patients and Ctrls (13.9 ± 3.8% vs 15.2 ± 5.1 and 17.6 ± 5.2%, p = 0.044) as was trabecular thickness (145.6 ± 23.1 vs 160.5 ± 22.7 and 153.7 ± 21.4 μm, p = 0.033). Mean structure model index was lower for IRs than U-OP patients (1.9 ± 0.806 vs 2.4 ± 0.687, p = 0.042) and osteoclast number was higher for IRs than U-OP patients and Ctrls (0.721 ± 0.611 vs 0.394 ± 0.393 and 0.199 ± 0.071 mm^-2, p < 0.001). The mean Obl.S/BS was lower for IRs than U-OP patients and Ctrls (1.2 ± 1.3 vs 1.9 ± 1.4 and 3.0 ± 0.638 mm^-2, p < 0.0001), and the mean number of labelled surfaces was lower for IRs than U-OP patients (51.6% vs 87%, p = 0.002). Cortical parameters did not significantly differ. We show an imbalance of bone remodeling in favor of bone resorption in IRs. The persistence of high bone resorption suggests insufficient inhibition of bone resorption that could explain the incident fractures with anti-osteoporotic drug use. Adaptation to treatment should be considered to inhibit bone resorption and prevent further fractures.

Impact of osteogenic activity on degenerative aortic valve disease in patients with osteoporotic hip fracture

BACKGROUND

Previous studies have proposed that osteogenic and apoptotic processes of valve interstitial cells contribute to the mineralization and then calcification of the aortic valve. Osteoblast-like cells subsequently mediate calcification of the aortic valve as part of a highly regulated process analogous to skeletal bone formation. The objective of this study was to evaluate the pathogenesis of the sclerotic/calcific changes in the aortic valve from histological and biological findings, and investigate the role of osteoblasts in the calcified pathway of aortic stenosis.

METHODS

Preoperative echocardiography in 550 consecutive patients with osteoporotic hip fracture were retrospectively examined (475 females, mean 25th-75th, 89 [85-93] years). One hundred sixteen patients were under medical treatment with anti-osteoporosis drugs. We evaluated the prevalence and degree of degenerative changes in the aortic valve and examined the associations of bone turnover biomarkers N-terminal pro-peptide of type 1 collagen (P1NP) and serum tartrate-resistant acid phosphatase (TRACP-5b) with degenerative calcific changes in the aortic valve.

RESULTS

Of 550 patients, 112 patients (20.9%) showed no leaflet calcification; 296 (53.8%), 1 leaflet calcification; and 142 (25.8%), 2 ≥ leaflets calcification. Significant (peak velocity ≥ 3.0m/s) Aortic stenosis was found in 43 patients (7.8%). In patients who were not taking anti-osteoporotic drugs, P1NP was higher in the 2 ≥ leaflets calcification group than in the other groups (p < 0.01). TRACP-5b was not significantly different among the three groups (p = 0.15).

CONCLUSIONS

Degenerative changes in the aortic valve were related to bone biomarker activation in osteoporotic hip fracture patients.

Role of Bone Turnover Markers in Osteoporosis Therapy

Bone turnover markers fill a clinical need that improves comprehensive care of metabolic bone health and osteoporosis. Creating a standard process for drawing them that reduces modifiable variability improves their precision and clinical usefulness. Creating a standard process for interpreting them by applying statistical significance improves their clinical applicability. Understanding what causes them to increase and decrease can help elucidate secondary causes of osteoporosis. Monitoring them can assess patient adherence to therapy for a silent disease that will progressively become louder with an aging global population.

Changes of bone turnover markers after elderly hip fracture surgery

INTRODUCTION

Bone turnover markers (BTMs) can be used to monitor bone metabolism, while the actual clinical changing in hip fracture had not been certified to evaluate the changes of BTMs during the healing process after surgery of elderly hip fractures; and to get the effects of operation type, gender, serum 25(OH)D level, and age on bone turnover markers.

MATERIALS AND METHODS

A total of 100 elderly cases with hip fracture were selected, including 74 females and 26 males, and the patients were followed to 180-230 days after surgery. Serum levels of N-propeptide of type 1 collagen (P1NP), C-terminal crosslinking telopeptides of type 1 collagen (CTX), Osteocalcin (OC), and 25 hydroxy vitamin D (25OHD) were investigated. Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry (DXA).

RESULTS

(1) P1NP and CTX showed peak time at 30-60 days after operation, while OC keep going even at 180-230 days; P1NP showed less than 4 times elevation during healing, CTX and OC only had less than 2 times rise. (2) Female had higher serum CTX and OC than male, intramedullary nailing for intertrochanteric fracture patients had higher P1NP than hip replacement for femoral neck fracture patients, and both the degrees of increase were less than 50%. (3) Serum average 25(OH)D level had no effect on BTMs during the fracture healing; different from the young old (65-84 years), serum OC level of eldest older patients(≥ 85 years) decreased early in the process of fracture healing.

CONCLUSIONS

BTMs reached the peak level in 30-60 days after surgery, P1NP showed less than 4 times elevation, and CTX and OC had less than 2 times rise. It was not necessary to take gender into account when observing P1NP, and it was not necessary to take fracture and operation type into account when observing CTX and OC.

Biological activity is not suppressed in mid-shaft stress fracture of the bowed femoral shaft unlike in "typical" atypical subtrochanteric femoral fracture: A proposed theory of atypical femoral fracture subtypes

BACKGROUND

We have investigated mid-shaft stress fractures of the bowed femoral shaft (SBFs), well before the first report of an association between suppression of bone turnover and atypical femoral fractures (AFFs). Although all cases of SBF meet the criteria for AFF, SBFs can also occur in patients with no exposure to bone turnover suppression-related drugs (e.g., bisphosphonates). Using bone morphometry and biomechanical analyses, we devised a theory of AFF subtypes, dividing AFFs into fragility SBFs in the mid-shaft and "typical" subtrochanteric AFFs caused by suppressed bone turnover. The aim of this multicenter prospective study was to provide evidence for this novel concept in terms of biological activity.

METHODS

The study was conducted at 12 hospitals in Japan from 2015 through 2019. Thirty-seven elderly women with AFF were included and classified according to location of the fracture into a mid-shaft AFF group (n = 18) and a subtrochanteric AFF group (n = 19). Patient demographics and clinical characteristics were investigated to compare the two groups. The main focus was on histological analysis of the fracture site, and bone metabolism markers were evaluated to specifically estimate biological activity.

RESULTS

All patients in the subtrochanteric AFF group had a history of long-term (>3 years) exposure to specific drugs that have been reported to cause AFF, but 5 of the 18 patients in the mid-shaft AFF group had no history of exposure to such drugs. Femoral bowing was significantly greater in the mid-shaft AFF group (p < 0.001). In the histological analysis, active bone remodeling or endochondral ossification was observed in the mid-shaft AFF group, whereas no fracture repair-related biological activity was observed in the majority of patients in the subtrochanteric AFF group. Levels of tartrate-resistant acid phosphatase-5b and undercaroxylated osteocalcin were significantly lower in the subtrochanteric AFF group (p < 0.05).

CONCLUSION

The possibility of our devised AFF subtype theory was demonstrated. Biological activity tends not to be suppressed in mid-shaft SBFs unlike in "typical" subtrochanteric AFFs involving bone turnover suppression. Although validation of the proposed theory in other populations is needed, we suggest that the pathology and treatment of AFFs be reconsidered based on its subtype.

Decreased markers of bone turnover in children and adolescents with type 1 diabetes

BACKGROUND AND AIM

Adults with type 1 diabetes (T1D) have increased risk of bone fractures and decreased bone mineral density (BMD). Alterations in bone turnover have been suggested as the link between T1D and the impaired bone health. Furthermore, bone turnover has been suggested to have beneficial effects on glucose metabolism. This study aimed at describing bone turnover markers (BTM), and the relationship with glycemic control, in children and adolescents with T1D.

METHODS

A total of 173 (47% girls) children and adolescents aged 7.7 to 17.5 years with T1D for more than 1 year were included. Participants were evaluated by BMD together with measurements of selected BTM; two formation markers: osteocalcin (OCN) and procollagen type-1 amino-terminal propeptide (P1NP) and one resorption marker, C-terminal cross-linked telopeptide of type-1 collagen (CTX). BTM were converted into Z-scores utilizing new national references.

RESULTS

Mean OCN Z-score (-0.68 ± 1.31), P1NP Z-score (-0.33 ± 1.03) and CTX Z-score (-0.43 ± 1.10) were all significantly lower than the reference population (P < .001). No associations were seen between BTM and T1D duration. BMD Z-score was comparable to the reference population and associated with none of individual BTMs. CTX Z-score was negatively associated with HbA1c (P = .007) independent of both exogenous and residual endogenous insulin.

CONCLUSIONS

Markers of bone formation and resorption were decreased in children and adolescents with T1D. CTX Z-score associated negatively with HbA1c adjusted for insulin treatment and endogenous insulin production indicating a potential association between CTX and insulin sensitivity. The long-term consequences of decreased BTM on BMD need further attention.

Structural and Metabolic Assessment of Bone

The assessment of bone structure and metabolism should focus on the bone strength. Many factors are involved, and although bone density is an important component, it is not the same as bone strength. Other aspects of bone quality include bone volume, micro-architecture, material composition, and ability to repair damage. This chapter briefly reviews some of the methods that can be used to assess both density and quality of bone. Non-invasive measurements of density or structure include dual X-ray absorptiometry (DXA), quantitative computed tomography, ultrasound, and magnetic resonance imaging. DXA is most widely used and has advantages of safety and accessibility, but there are limitations in the interpretation of the results, and in clinical practice positioning errors are frequently seen. Invasive methods are used primarily for research. Samples of bone can be used to measure structure by histology as well as micro-computed tomography and infra-red spectroscopy or backscattered electron microscopy. Force can be directly applied to bone samples to measure the bones strength. Impact microindentation is a new minimally invasive technique that measures bone hardness. Metabolic assessment includes blood and urine tests that reflect diseases that cause bone loss, particularly problems with mineral metabolism. Tetracycline-labelled bone biopsies are the standard for measuring bone formation. Non-invasive biochemical tests of bone formation and resorption can evaluate a patient's skeletal physiology.

The combined effects of teriparatide and anti-RANKL monoclonal antibody on bone defect regeneration in ovariectomized mice

OBJECTIVE

The purpose of this study was to investigate the combined effects of teriparatide (TPTD) and anti-murine receptor activator of nuclear factor-κB ligand monoclonal antibody (anti-RANKL Ab) on both cancellous and cortical bone healing in ovariectomized mice.

METHODS

Thirteen-week-old mice were divided into the sham-operated group (n=11) or the ovariectomized group (n=44). At 1 month post-operation, all mice underwent bone defect surgery on the left femoral metaphysis (cancellous bone healing model) and right femoral mid-diaphysis (cortical bone healing model). After creating the bone defects, all ovariectomized mice were assigned to one of four groups to receive 1) saline (5 times a week; CNT group), 2) TPTD (40μg/kg 5 times a week; TPTD group), 3) anti-RANKL Ab (5mg/kg once; Ab group), or 4) a combination of TPTD and anti-RANKL Ab (COMB group). The following analyses were performed: Time-course microstructural analysis of healing in both cancellous and cortical bone in the bone defect, measuring the volumetric bone mineral density and the cortical bone thickness of the tibia as a representative of whole body bone with the use of micro-computed tomography, and histological analysis.

RESULTS

Regeneration of cancellous bone volume in the COMB group was the highest among the four groups, and combined treatment accelerated the formation of medullary callus during the early phase of bone regeneration. On the other hand, there were no significant differences in the regeneration of cortical bone volume during the early phase of bone regeneration among the four groups. Furthermore, lamellar bone was not well identified in the all four groups. Volumetric bone mineral density in the tibia in the COMB group was significantly higher compared with that in the CNT and TPTD groups and tended to be higher compared with that in the Ab group. The mean values of cortical bone thickness in the TPTD and COMB groups were significantly higher than that in the CNT group.

CONCLUSION

In a mouse model of postmenopausal osteoporosis, combination therapy of TPTD and anti-RANKL Ab accelerates regeneration of cancellous bone more effectively than either agent alone during the early phase of bone regeneration.

Fracture-induced changes in biomarkers CTX, PINP, OC, and BAP-a systematic review

To assess the time from fracture until bone turnover markers (BTM), which are biochemical markers reflecting in vivo bone formation and resorptive activity, have returned to a stable level since BTM have been shown to be at least as good as bone mineral density in monitoring the effect of anti-resorptive treatment in osteoporosis. This study searched for articles in PUBMED, CINAHL, Medline, EM-BASE, and Cochrane, and identified 3486 unique articles. These articles were screened based on predefined inclusion and exclusion criteria. Seven articles addressing time to normalization of either CTX, PINP, osteocalcin, or bone-specific alkaline phosphatase after a recent fracture were identified and these were analyzed qualitatively. CTX appeared to return to baseline within 6 months. PINP appeared to return to baseline within 6 months and interestingly dip below baseline after a year. Osteocalcin was elevated throughout the first year after a fracture, with most changes in the first 6 months. Bone-specific alkaline phosphatase (BAP) was increased for up to a year, however with a discrepancy between used assays. Seven studies were identified, showing CTX and PINP to return to baseline within 6 months. OC was elevated for 12 months. BAP was increased for up to a year. However, none of these studies had fasting patients and a long follow-up period with regular measurements. The studies could indicate that the BTM CTX and PINP have returned to baseline within 6 months; however, further studies are needed assessing pre-analytical factors while having a long follow-up. Bone turnover markers appear as good as or better than bone mineral density in monitoring the effect of anti-resorptive medication in osteoporosis. This study tries to identify the time from fracture until BTM are back at baseline. Most studies did not however take pre-analytical variation into consideration. Further research is therefore needed.

Bone Stress Injuries Are Associated With Differences in Bone Microarchitecture in Male Professional Soldiers

Bone stress injuries are commonly due to repetitive loading, as often described in competitive athletes or military recruits. The underlying pathophysiology of bone stress injuries is multifactorial. The present cross-sectional study investigated (i) cortical and trabecular bone microstructure as well as volumetric bone mineral density in subjects with bone stress injuries at the tibial diaphysis, measured at the distal tibia and the distal radius by means of high-resolution peripheral quantitative computed tomography (CT), (ii) areal bone mineral density using dual-energy X-ray absorptiometry as well as calcaneal dual X-ray absorptiometry and laser, and (iii) the influence on bone turnover markers of formation and resorption at the early phase after injury. A total of 26 Caucasian male professional soldiers with post-training bone stress injury at the tibial diaphysis were included (case group). A total of 50 male, Caucasian professional soldiers from the same military institution served as controls (control group). High-resolution peripheral quantitative CT revealed a higher total area at the radius within the case group. Cortical bone mineral density was reduced at the radius and tibia within the case group. The trabecular number and trabecular thickness were reduced at the tibia in the case group. The trabecular network was more inhomogeneous at the radius and tibia within the case group. Calcaneal dual X-ray absorptiometry and laser was significantly reduced in the case group. This study quantified differences in bone microstructure among otherwise healthy individuals. Differences in bone microarchitecture may impair the biomechanical properties by increasing the susceptibility to sustain bone stress injuries. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2516-2523, 2019.

Efficacy and safety of elcatonin in postmenopausal women with osteoporosis: a systematic review with network meta-analysis of randomized clinical trials

The present systematic review aimed to evaluate bone mineral density (BMD) change and complication rates of elcatonin on treating postmenopausal osteoporosis. The result confirmed efficacy of elcatonin and safety in combination therapies of elcatonin (C-E).

INTRODUCTION

Postmenopausal osteoporosis is an important issue in global aging trends. One treatment of osteoporosis is elcatonin, a kind of calcitonin. However, it has been challenged for long time because of safety. Many trials investigated on this topic, but they were designed differently. Those designs can be categorized in monotherapy of elcatonin (M-E) and C-E. Unfortunately, no synthesized evidence dealt this topic.

METHODS

This study systematically identified target trials from six important databases and only included randomized controlled trial for synthesis. Two investigators assessed quality of eligible trials using the Cochrane Risk of Bias Tool, and they independently extracted data. Network meta-analysis performed Peto odds ratio (POR, used for dealing with zero cell) or weighted mean difference (WMD, for continuous data) with 95% confidence intervals (CI) and consistency H.

RESULTS

Sixteen trials recruiting 2754 women with postmenopausal osteoporosis were included in our study. Elcatonin therapies and non-elcatonin medications had comparable fracture rates and bone mineral density change. Yet, C-E (WMD, - 18.93; 95% CI, - 23.97 to - 13.89) and M-E (WMD, - 13.72; 95% CI, - 19.51 to - 7.94) had significantly lower pain score than non-elcatonin medications. However, M-E (POR = 8.413, 95% CI, 2.031 to 34.859) and non-elcatonin medication (Peto OR, 7.450; 95% CI, 1.479 to 37.530) had significantly higher complication rates than placebo. No evidence detected inconsistency and small study effect in this network model.

CONCLUSIONS

Based on current evidence, C-E may be considered for treating postmenopausal osteoporosis because it benefits on pain relief and complications. Moreover, it shows comparable fracture rate and bone mineral density change as compared with anti-osteoporosis and calcium supplements. Nevertheless, further trials are needed to investigate formula and dosages of elcatonin.

Biomarkers of bone healing induced by a regenerative approach based on expanded bone marrow-derived mesenchymal stromal cells

BACKGROUND

Safety and feasibility of a regenerative strategy based on the use of culture-expanded mesenchymal stromal cells (MSCs) have been investigated in phase 2 trials for the treatment of nonunion and osteonecrosis of the femoral head (ONFH). As part of the clinical study, we aimed to evaluate if bone turnover markers (BTMs) could be useful for predicting the regenerative ability of the cell therapy product.

MATERIALS AND METHODS

The bone defects of 39 patients (nonunion: n = 26; ONFH: n = 13) were treated with bone marrow-derived MSCs, expanded using a clinical-grade protocol and combined with biphasic calcium phosphate before implantation. Bone formation markers, bone-resorption markers and osteoclast regulatory proteins were measured before treatment (baseline) and after 12 and 24 weeks from surgery. At the same time-points, clinical and radiological controls were performed to evaluate the bone-healing progression.

RESULTS

We found that C-Propeptide of Type I Procollagen (CICP) and C-terminal telopeptide of type-I collagen (CTX) varied significantly, not only over time, but also according to clinical results. In patients with a good outcome, CICP increased and CTX decreased, and this trend was observed in both nonunion and ONFH. Moreover, collagen biomarkers were able to discriminate healed patients from non-responsive patients with a good diagnostic accuracy.

DISCUSSION

CICP and CTX could be valuable biomarkers for monitoring and predicting the regenerative ability of cell products used to stimulate the repair of refractory bone diseases. To be translated in a clinical setting, these results are under validation in a currently ongoing phase 3 clinical trial.

Precision Medicine Applications to Manage Multiply Injured Patients With Orthopaedic Trauma

Precision medicine offers potential for improved outcomes by tailoring interventions based on patient-specific demographics and disease-specific data. Precision methods are relatively unexplored in trauma patients. New research is being looked at for precision methods to treat patients with large extremity wounds, nonunions, and fractures associated with polytrauma. Precision-based clinical decision tools are being validated to optimize timing for open wound definitive closure. Early patient-specific biomarkers to stratify nonunion risk within 1 week of fracture are being explored. Patient-specific data to stage timing of major fracture interventions in multiply injured patients are being interrogated.

Serum 25(OH)D is associated with an altered bone turnover marker response after a hip fracture

C-terminal telopeptide of type I collagen (CTX) and procollagen type 1 N-terminal propeptide (P1NP) are bone turnover markers (BTMs) that are promising surrogate measures of fracture healing; however, it is unknown if their response is affected by other bone healing metabolites. Since 70% of fracture patients are reported to have insufficient serum vitamin D, we sought to determine if serum 25(OH)D levels are associated with differential changes in CTX and P1NP concentrations after hip fracture. This prospective cohort included hip fracture patients 65 years of age or older admitted to one of eight Baltimore-area hospitals. Serum samples were collected at baseline, 2-, 6-, and 12-month post-fracture. A mixed-effects repeated-measures analysis was used to determine the longitudinal association between vitamin D deficiency (25(OH)D < 20 ng/ml) and CTX and P1NP. Baseline lab values were obtained for 296 participants (mean age, 80.8 years; 51% male; 55% 25(OH)D < 20 ng/ml). During the acute fracture healing period P1NP concentrations increased by 14% (95%CI: 7-21%, p < 0.01) while CTX levels did not change (p = 0.07). Both CTX and P1NP decreased below baseline at 6 and 12 months. CTX levels were higher in participants with baseline 25(OH)D < 20 ng/ml (p = 0.01). There was no association between 25(OH)D < 20 ng/ml and P1NP levels over the study duration (p = 0.33). Data from this large, longitudinal cohort support claims that CTX and P1NP concentrations change during fracture healing; however, the differential response of CTX among vitamin D deficient patients highlights important questions for its utility as a reliable surrogate marker of fracture healing. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Spontaneous vertebral fractures after denosumab discontinuation: A case collection and review of the literature

OBJECTIVE

Denosumab is an antiresorptive drug with demonstrated efficacy in the treatment of osteoporosis. However, discontinuation of this agent is associated with increased bone turnover and rapid bone loss, and more recently, with the development of vertebral fractures (VF) in some patients. Therefore, the aim of the study was to analyze the clinical characteristics, bone metabolism parameters and evolution of a group of patients who developed vertebral fractures after denosumab discontinuation. In addition, we reviewed the literature on this subject.

METHODS

During a period of 28 months (September 2015-January 2018) 7 women presenting spontaneous vertebral fractures after denosumab discontinuation were attended in the Rheumatology Department of our centre. We analyzed their clinical characteristics, bone metabolism parameters and evolution and reviewed the literature related to this subject.

RESULTS

The patients had received denosumab during 24-58 months (median 38), and developed a median of 5 VF per patient at 8-20 months (median 10) since the last dose of denosumab. Only 2 patients presented previous VF, and most (5 patients) received previous bisphosphonate treatment. After VF all restarted antiosteoporotic treatment with no further fractures during follow-up (median 19 months).

CONCLUSIONS

In this short series, previous bisphosphonate treatment does not seem to be a protective factor for the development of VF. The possible development of VF following discontinuation of denosumab must be taken into account in the clinical practice of physicians and dentists. Nonetheless, further studies are needed to improve the identification of patients at risk and the most adequate sequential treatment options.

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.

Use of bone turnover markers in the management of osteoporosis

PURPOSE OF REVIEW

Osteoporosis is a common public health problem that is often undertreated and underdiagnosed. The clinical management of osteoporosis is often reactionary to devastating fracture events. Bone turnover markers may improve the ease and rapidity at which osteoporosis is monitored and treated. Bone turnover markers are biochemical byproducts of bone formation or bone resorption. The clinical use of bone turnover markers is limited by significant preanalytical variability. Effective interpretation of bone turnover markers requires a detailed understanding of the variables that can affect their responses to osteoporosis treatment and monitoring.

RECENT FINDINGS

Progress is continuously being made on the standardization of bone turnover markers. The literature on the response of bone turnover markers to unique clinical situations is expanding. Data for evidence-based reference intervals for bone turnover markers has increased. Variables that affect the appropriate timing of lab draws like diurnal variation, postprandial status, exercise and alcohol use have been described. Studies examining the expected response of bone turnover markers to treatments of osteoporosis and other medications that affect bone health continue to increase.

SUMMARY

Bone turnover markers have clinical utility in the comprehensive evaluation of osteoporosis. When interpreted with caution and with a good understanding of their natural variability, bone turnover markers provide information that supplements osteoporosis management and provides useful clinical information about conditions that alter bone turnover.

Effects of nutritional intervention upon bone turnover in elderly hip fracture patients. Randomized controlled trial

BACKGROUND AND AIM

Hip fracture patients are at great risk of malnutrition, but documentation of the effect of nutrition supplementation in this group is sparse and inconclusive. The aim of this study was to examine if personalized nutrition advice combined with vitamin K1, Ca and vitamin D could improve bone turnover 4 months after hip fracture.

DESIGN

This is a preplanned sub study of a randomized controlled trial of orthogeriatric care. The intervention group received orthogeriatric care, including nutrition advice and supplementation. The control group received usual care at the orthopedic ward. Blood was drawn for measurements of a number of vitamins and of bone turnover markers upon admission and at four months follow up.

RESULTS

71 patients (31 in the intervention group and 40 controls) had available data at 4 months as well as at baseline. After four months, vitamin K1 and 25(OH)D were higher in the intervention group compared with controls; vitamin K1: 1.0 ± 1.2 vs 0.6 ± 0.6 ng/ml, p = 0.09, 25(OH)D: 60 ± 29 vs 43 ± 22 nmol/L, p = 0.01 when adjusted for baseline differences. In a secondary, unadjusted analysis, comprising all patients with available four months data (n = 136), the differences were statistically significant for vitamin K1 as well as 25(OH)D (p = 0.03 and p < 0.001, respectively). There was a non-significant increase in 25(OH)D in the intervention group from baseline to 4 months follow up, and a significant decrease in the control group. There was no difference in bone turnover markers between the two groups at 4 months follow up. A substantial loss of weight and physical function was found in both groups.

CONCLUSIONS

The supplementation of 25(OH)D and vitamin K1 improved serum concentrations of these vitamins, but this did not translate into any improvement in the bone turnover markers. The RCT is registered in ClinicalTrials.govNCT01009268 and NCT01738776.

Association of Adrenergic Receptor α2A (α2A-AR) Gene rs1800544 Polymorphism with Bone Mineral Density and Bone Turnover Markers in an Elderly Chinese Population

BACKGROUND Adrenergic receptor α2A (α2A-AR) is up-regulated in osteoporotic bone osteoblasts. Previous research demonstrated an association between polymorphism of a2A-AR gene and bone mineral density (BMD) as well as bone turnover markers (BTMs) in the Slovenian population. The present study aimed to investigate the association of rs1800544 polymorphism of α2A-AR gene with BMD and BTMs in the Chinese elderly population with osteoporosis (OP) or with osteoporotic fractures. MATERIAL AND METHODS A total of 346 unrelated elderly individuals were recruited in the study. Rs1800544 polymorphism was determined by Snapshot technology. BTMs were determined by electrochemiluminescence. BMDs at lumbar spine (LS) and proximal femur were measured with dual-energy X-ray absorptiometry (DEXA). Hardy-Weinberg equilibrium and distribution of genotype frequencies were verified using the chi-squared test. Analysis of co-variance (ANCOVA) adjusted for confounding factors was performed to explore the relationship of rs1800544 polymorphism with BMD and BTMs in all participants and in subgroups. RESULTS The genotype distributions in all subjects and in subgroups conformed to Hardy-Weinberg equilibrium (P>0.1). Distribution of genotype frequencies of subgroups showed no significant differences (P>0.05). Patients with GG genotype in the fracture group had significantly higher serum BTMs level compared with those carrying other genotypes (P<0.05). No significant association between rs1800544 and BTMs was detected in the elderly population with OP. Comparison of BMD at each site in all participants did not show any significant difference in subgroups with CC, CG, and GG genotypes (P>0.05). CONCLUSIONS Rs1800544 polymorphism is associated with BTMs level in Chinese elderly individuals with osteoporotic fractures, indicating the involvement of genetic variation of a2A-AR gene in bone metabolism.

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.

Serum proteomic assessment of the progression of fracture healing

A targeted proteomic analysis of murine serum over a 35-day course of fracture healing was carried out to determine if serum proteomic changes could be used to monitor the biological progression of fracture healing. Transverse, closed femoral fractures where generated and stabilized with intramedullary fixation. A single stranded DNA aptamer-based multiplexed proteomic approach was used to assay 1,310 proteins. The transcriptomic profiles for genes matching the 1,310 proteins were obtained by microarray analysis of callus mRNA. Of the 1,310 proteins analyzed, 850 proteins showed significant differences among the time points (p-value <0.05). Ontology assessment associated these proteins with osteoblasts, monocyte/macrophage lineages, mesenchymal stem cell lines, hepatic tissues, and lymphocytes. Temporal clustering of these data identified proteins associated with inflammation, cartilage formation and bone remodeling stages of healing. VEGF, Wnt, and TGF-βsignaling pathways were restricted to the period of cartilage formation. Comparison of the proteomic and transcriptomic profiles showed that 87.5% of proteins in serum had concordant expression to their mRNA expression in the callus, while 12.5% of the protein and mRNA expression patterns were discordant. The discordant proteins that were elevated in the serum but down regulated in callus mRNA expression were related to clotting functions, allograft rejection, and complement function. While proteins down regulated in the serum and elevated in callus mRNA were associated with osteoblast function, NF-ĸb, and activin signaling. These data show the serum proteome may be used to monitor the different biological stages of fracture healing and have translational potential in assessing human fracture healing. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1153-1163, 2018.