Acute Effects of Strength and Endurance Training on Bone Turnover Markers in Young Adults and Elderly Men

CONTEXT

Exercise is recognized as an important strategy to prevent bone loss, but its acute effects on bone turnover markers (BTMs) and related markers remain uncertain.

OBJECTIVE

To assess the acute effects of two different exercise modes on BTMs and related markers in young adults of both sexes and elderly men.

DESIGN SETTING PARTICIPANTS

This was a three-group crossover within-subjects design study with a total of 53 participants-19 young women (aged 22-30), 20 young men (aged 21-30 years), and 14 elderly men (aged 63-74 years)-performing two different exercise sessions [strength training (ST) and high-intensity interval training (HIIT)] separated by 2 weeks, in a supervised laboratory setting.

MAIN OUTCOME MEASURES

Plasma volume-corrected serum measurements of the BTMs C-terminal telopeptide of type 1 collagen (CTX-I) and procollagen of type 1 N-terminal propeptide (P1NP), total osteocalcin (OC), sclerostin, and lipocalin-2 (LCN2) at baseline, immediately after, and 3 and 24 h after each of the two exercise modes were performed.

RESULTS AND CONCLUSION

Analyses revealed sex- and age-dependent differences in BTMs and related bone markers at baseline and time-, sex-, and age-dependent differences in response to exercise. No differences between exercise modes were observed for BTM response except for sclerostin in young men and LCN2 in elderly men. An acute, transient, and uniform increase in P1NP/CTX-1 ratio was found in young participants, demonstrating that beneficial skeletal effects on bone metabolism can be attained through both aerobic endurance and resistance exercise, although this effect seems to be attenuated with age. The acute effects of exercise on bone-related biomarkers were generally blunted after 24 h, suggesting that persistent alterations following prolonged exercise interventions should be assessed at later time points.

Acute CTX-1 Suppression With Milk Calcium or Calcium Carbonate is Independent of Visceral Fat in A Randomized Crossover Study in Lean and Overweight Postmenopausal Women

BACKGROUND

Postmenopausal women with higher visceral adipose tissue (VAT) present with suppressed bone resorption (lower c-terminal cross-linking telopeptide of type I collagen, CTX-1) and turnover (lower osteocalcin) but whether this blunts the effect of calcium is unknown.

OBJECTIVE

The primary outcome of this study was the effect of VAT on changes in CTX-1 after intake of two forms of calcium. Secondary outcomes included changes in parathyroid hormone (PTH), serum calcium, phosphorus, and alkaline phosphatase (ALP).

DESIGN

Randomized open three period crossover trial conducted between 2017-2019 at the University of South Australia among 77 lean and overweight postmenopausal women (53-79 y) with body mass index (BMI) less than 25 kg/m2 and greater than 27 kg/m2, respectively. Participants received a single dose of milk (1000 mg calcium), calcium carbonate tablet (1000 mg calcium), and fruit juice (no calcium) in random order with a seven-day washout period. Blood samples were collected at baseline and hourly for 5h. Data was analysed by repeated measures analysis of variance (ANOVA) of log-transformed data.

RESULTS

At baseline, women with higher VAT had significantly lower CTX-1 and higher PTH (44% lower and 30% higher, respectively between Q4 and Q1, P < 0.0001). VAT had no influence on the acute changes in CTX-1 or PTH with calcium or juice. A suppression of 44% in CTX-1 was seen with calcium carbonate and milk and a suppression of 18% with juice. PTH was suppressed more with calcium carbonate (47%) compared to milk (22%). Milk calcium reduced PTH and CTX-1 at 2-hour while calcium carbonate reduced PTH in 1 hour. The suppression in CTX-1 was slower with lowest levels at 4-5 hour.

CONCLUSIONS

1000 mg calcium obtained from milk or from calcium carbonate is effective in acutely suppressing bone resorption in postmenopausal women irrespective of visceral fat.This trial is registered with the Australian New Zealand Clinical Trials Registry http://www.ANZCTR.org.au/ACTRN12617000779370.aspx (ACTRN 12617000779370).

A functional three-dimensional microphysiological human model of myeloma bone disease

Human myeloma bone disease (MBD) occurs when malignant plasma cells migrate to the bone marrow and commence inimical interactions with stromal cells, disrupting the skeletal remodeling process. The myeloma cells simultaneously suppress osteoblastic bone formation while promoting excessive osteoclastic resorption. This bone metabolism imbalance produces osteolytic lesions that cause chronic bone pain and reduce trabecular and cortical bone structural integrity, and often culminate in pathological fractures. Few bone models exist that enable scientists to study MBD and the effect therapies have on restoring the bone metabolism imbalance. The purpose of this research was to develop a well characterized three-dimensional (3D) bone organoid that could be used to study MBD and current or potential treatment options. First, bone marrow stromal cell-derived osteoblasts (OBs) mineralized an endosteal-like extracellular matrix (ECM) over 21 days. Multiple analyses confirmed the generation of hydroxyapatite (HA)-rich bone-like tissue fragments that were abundant in alkaline phosphatase, calcium, and markers of osteoblastic gene expression. On day 22, bone marrow macrophage (BMM)-derived osteoclasts (OCs) were introduced to enhance the resorptive capability of the model and recapitulate the balanced homeostatic nature of skeletal remodeling. Tartrate-resistant acid phosphatase 5b (TRAcP-5b), type I collagen C-telopeptide (CTX-1), and gene expression analysis confirmed OC activity in the normal 3D organoid (3D in vitro model of normal bonelike fragments [3D-NBF]). On day 30, a human multiple myeloma (MM)-derived plasmacytoma cell line was introduced to the 3D-NBF to generate the 3D-myeloma bone disease organoid (3D-MBD). After 12 days, the 3D-MBD had significantly reduced total HA, increased TRAcP-5b levels, increases levels of CTX-1, and decreased expression of osteoblastic genes. Therapeutic intervention with pharmaceutical agents including an immunomodulatory drug, a bisphosphonate, and monoclonal restored HA content and reduced free CTX-1 in a dose-dependent manner. This osteogenically functional model of MBD provides a novel tool to study biological mechanisms guiding the disease and to screen potential therapeutics. © 2021 American Society for Bone and Mineral Research (ASBMR).

Visceral Fat Is a Negative Determinant of Bone Health in Obese Postmenopausal Women

The protective effect of obesity on bone health has been challenged by studies that link visceral adiposity to poor bone microarchitecture in young obese men and women. In postmenopausal women, the role of visceral adipose tissue (VAT) on bone turnover markers (BTMs) has not been investigated. The aim was to investigate the impact of VAT on BTMs, total bone mineral density (BMD), vitamin D metabolites and parathyroid levels (1-84 PTH) levels in postmenopausal women. A total of 76 lean and overweight women (without osteoporosis) underwent VAT measurements by dual-energy X-ray absorptiometry (iDXA). Blood samples were analyzed for serum C-terminal telopeptide of type 1 collagen (CTX-1), osteocalcin, bone-specific alkaline phosphatase (bone ALP), 1–84 PTH and vitamin D (25 hydroxyvitamin D, 25(OH)D) levels. VAT volumes ranged from 91 to 3392 cm³ and body mass index (BMI) ranged from 18.3 to 53.9 kg/m². Women in the highest VAT quartile had significantly lower CTX-1, 25(OH)D, osteocalcin and the highest BMD (p < 0.05, for all). While VAT positively associated with BMD, after controlling for BMI, VAT was a negative predictor of BMD (β = 0.368, p < 0.05). VAT was an independent negative predictor of CTX-1 (β = −0.263, p < 0.05) and osteocalcin levels (β = −0.277, p < 0.05). Among all measures of adiposity, VAT was the strongest independent determinant of BMD and BTMs. In clinical settings, VAT, and not BMI, may be a sensitive predictor of bone health in obese women.

Urinary cross-linked carboxyterminal telopeptide, a bone resorption marker, decreases after vaso-occlusive crises in adults with sickle cell disease

People with sickle cell disease often report severe bone pain with repeated bouts of vaso-occlusive crises, but the extent of skeletal injury incurred during these painful episodes remain unclear. We sought to quantify bone degradation by comparing urinary concentrations of carboxyterminal cross-linked telopeptide of type I collagen (CTX-1), a well-described marker of bone resorption, in a prospective cohort of 52 adults with sickle cell disease enrolled in the Sickle Cell Pain Markers Study. We also questioned if changes in urinary CTX-1 concentrations correlated with changes in hemolysis and inflammatory markers measured both during and after resolution of a painful vaso-occlusive episode. Thirty-one of the 52 adults enrolled in the study had paired urine samples for CTX-1 analysis. Urinary CTX-1, corrected for urine creatinine, significantly decreased from a mean of 3.45 μg/mmol during vaso-occlusive crises to 2.62 μg/mmol at recovery (p = 0.01). Thus, increased bone loss appears to correlate with acute vaso-occlusive crises in sickle cell disease. Our finding that urinary CTX-1 can be used to probe bone degradation in sickle cell disease provides an important new tool for diagnosing and monitoring response to therapy for people with sickle cell-related bone loss.

Low bone turnover levels predict increased risk of cancer

BACKGROUND

Several epidemiological studies have shown an association between bone mineral density (BMD) and risk of breast cancer in postmenopausal women, but it remains unknown whether bone turnover is associated with increased risk of cancer. The aim of this study was to investigate if markers of bone formation and resorption are associated with increased risk of cancer.

MATERIAL AND METHODS

The study population included 5855 postmenopausal Danish women enrolled in the Prospective Epidemiologic Risk Factor (PERF) study. Cancer diagnosis was obtained from the Danish Cancer Registry. Baseline spine, femur, and whole-body BMD were evaluated by DXA-scanners. Baseline bone turnover (CTX-1 and osteocalcin) were measured in serum. Multivariate Cox analysis was performed with 3, 6 and 12 years of follow-up. All continuous variables were transformed into z-score for the cox analyses.

RESULTS

252 developed cancer after 3 years, 462 developed cancer after 6 years, and 881 developed cancer with 12 years of follow-up. CTX-1, osteocalcin and spine BMD were all predictors of cancer at all time points (3 years of follow-up: Spine BMD, HR = 1.20, p = 0.003; CTX-1, HR = 0.82, p = 0.005; osteocalcin, HR = 0.75, p < 0.001). After adjusting for cancer risk factors and other bone measures CTX-1 and osteocalcin remained independent predictors of cancer (3 years of follow-up: CTX-1, HR = 0.82, p = 0.02; osteocalcin, HR = 0.75, p = 0.002).

CONCLUSIONS

We found that levels of the bone turnover markers CTX-1 and osteocalcin were inversely associated with risk of cancer independent of BMD and other known cancer risk factors in postmenopausal women.

Effects of vitamin D supplementation on bone turnover markers and other bone-related substances in subjects with vitamin D deficiency

In observational studies, vitamin D deficiency is a risk factor for low bone density and future fractures, whereas a causal relation has been difficult to show in randomized controlled trials (RCTs). Similarly, vitamin D deficiency has been associated with increased bone turnover, but RCTs with vitamin D have not shown conclusive effects. This could be due to inclusion of vitamin D sufficient subjects and low vitamin D doses. In the present study 399 subjects with mean baseline serum 25-hydroxyvitamin D (25(OH)D) 34.0 nmol/L completed a four months intervention with vitamin D₃ 20,000 IU per week versus placebo. Mean serum 25(OH)D increased to 89.0 nmol/L in the vitamin D group and decreased slightly in the placebo group. A small, but significant, decrease in the bone formation marker procollagen of type 1 amino-terminal propeptide (P1NP) was seen in the vitamin D group as compared to the placebo group (mean delta P1NP -1.2 pg/mL and 1.5 ng/mL, respectively, P < 0.01). No significant effects were seen on serum carboxyl-terminal telopeptide of type 1 collagen (CTX-1), Dickkopf-1, sclerostin, tumor necrosis factor-alpha, osteoprotegerin, receptor activator of nuclear factor ĸB ligand, or leptin. Subgroup analyses on subjects with low baseline serum 25(OH)D did not yield additional, significant results. In subjects with high baseline serum parathyroid hormone (PTH) > 6.5 pmol/L and post-intervention decrease in PTH, the decrease in P1NP was more pronounced, they also exhibited significantly reduced serum CTX-1 and increased serum sclerostin. In conclusion, supplementation with vitamin D appears to suppress bone turnover, possibly mediated by PTH reduction. Our findings need to be confirmed in even larger cohorts with vitamin D insufficient subjects.

Bone resorption correlates with the frequency of CD5⁺ B cells in the blood of patients with rheumatoid arthritis

OBJECTIVE

The prevention of bone resorption and subsequent joint destruction is one of the main challenges in the treatment of patients suffering from RA. Various mechanisms have previously been described that contribute to bone resorption in tightly defined cohorts. Here we analysed a cross-sectional cohort of RA patients and searched for humoral and cellular markers in the peripheral blood associated with bone resorption.

METHODS

We enrolled 61 consecutive RA patients positive for ACPA. Blood was analysed by flow cytometry to determine the percentages of regulatory T cells and B cell subpopulations. Cytokine (TNF-α, IL-6, IL-10) and ACPA levels as well as the bone resorption marker CTX-1 were determined from the patients' sera. Standard clinical disease parameters were included.

RESULTS

Multivariate analyses showed that the percentages of CD5(+) B cells were positively correlated with CTX-1 serum levels. However, neither low-avidity ACPA nor serum IL-6 levels, both known to be produced by CD5(+) cells, were associated with CTX-1 in patients' sera. There was no correlation between CTX-1 levels and clinical parameters or ACPA levels.

CONCLUSION

In summary, we found that the CD5(+) B cell population is associated with bone resorption as measured via serum CTX-1 levels in a cross-sectional cohort of RA patients. However, a possible functional link between CD5(+) B cells and bone resorption still needs to be defined.

Plasma osteopontin is correlated with bone resorption markers in rheumatoid arthritis patients

AIM

To assess whether any form of osteopontin (OPN) is correlated with bone resorption markers or treatment effects in rheumatoid arthritis (RA).

METHOD

Subjects comprised 119 patients with RA. RA disease activity was evaluated by Disease Activity Score (DAS) 28, erythrocyte sedimentation rate (ESR), and levels of C-reactive protein (CRP), rheumatoid factor (RF) and matrix metalloproteinase (MMP)-3. OPN levels in plasma and urine were measured by enzyme-linked immunosorbent assay (ELISA). Levels of tartrate-resistant acid phosphatase (TRACP) 5b in serum and C-terminal telopeptide of type 1 collagen (CTX)-1 in urine were measured by ELISA. Patients were divided into responder and nonresponder groups, and OPN levels were compared at baseline and after treatment.

RESULTS

Levels of full-length OPN in plasma (P-fOPN) were significantly correlated with levels of TRACP 5b (r = 0.44, P < 0.001), urine CTX-1 (r = 0.26, P = 0.004) and MMP-3 (r = 0.34, P < 0.001). Levels of TRACP 5b were significantly correlated with age (r = 0.25, P = 0.007), but levels of P-fOPN were not. After treatment, plasma OPN levels were significantly decreased in responders (P = 0.003). Levels of full-length or thrombin-cleaved forms of OPN in urine were not correlated with TRACP 5b or CTX-1.

CONCLUSION

Our results suggest that plasma OPN may reflect inflammatory bone destruction in RA patients.