Biochemical markers of bone turnover. A look at laboratory tests that reflect bone status

Negative impact on bone homeostasis in postmenopausal women with non-metastatic breast cancer during cytotoxic chemotherapy

INTRODUCTION

The burden and mechanisms of endocrine therapy-related bone loss are well known, while there are limited data on chemotherapy-induced bone resorption. The study aimed to evaluate the effect of cytotoxic chemotherapy on bone homeostasis among postmenopausal women with non-metastatic breast cancer.

MATERIALS AND METHODS

Early and locally advanced postmenopausal non-metastatic breast cancer patients aged 45 to 65 planned for three cycles of anthracycline and four cycles of taxane chemotherapy administered along with dexamethasone (cumulative dose-256 mg) as an antiemetic from June 2018 to December 2021 were included. Bone mineral density (BMD), bone turnover markers, calciotropic hormones, pro-inflammatory cytokines, oxidative stress, and total antioxidant levels (TAS) were measured.

RESULTS

We recruited 109 patients, with early 34 (31.2%) and locally advanced breast cancer 75 (68.8%) with median age 53 (45-65) years. There was a significant decrease in the % BMD at the lumbar spine, neck of the femur, and total hip post-chemotherapy. There was a significant increase in serum C-terminal telopeptide of type I collagen (CTX) and procollagen type I N-terminal propeptide (PINP) levels post-chemotherapy. PINP/CTX ratio significantly decreased post-chemotherapy. Serum 25-OH vitamin D was significantly reduced with a compensatory increase in plasma iPTH levels. The change in CTX, PINP/CTX ratio, 25-OH vitamin D, iPTH, and oxidative stress index was more pronounced during anthracycline as taxane chemotherapy. There were no significant changes in pro-inflammatory cytokine levels.

CONCLUSION

Chemotherapy and dexamethasone as antiemetic resulted in significant bone loss, as evidenced by bone turnover markers. Further studies are required to understand the mechanism of chemotherapy-induced bone loss and the need for bone-strengthening agents during chemotherapy.

Cytotoxic chemotherapy is associated with decreased bone mineral density in postmenopausal women with early and locally advanced breast cancer

PURPOSE

The burden and mechanisms of endocrine therapy-related bone loss have been studied in detail. However, there is limited data regarding cytotoxic chemotherapy's impact on bone health. There are no definitive guidelines for bone mineral density (BMD) monitoring and treatment with bone-modifying agents during cytotoxic chemotherapy. The study's primary objective was to evaluate the changes in BMD and fracture risk assessment tool (FRAX) scores among breast cancer women on cytotoxic chemotherapy.

METHODS

One hundred and nine newly diagnosed early and locally advanced postmenopausal breast cancer patients planned for anthracycline and taxane-based chemotherapy were recruited prospectively during the study period from July 2018 to December 2021. BMD of the lumbar spine, the femoral neck, and the total hip were assessed by dual-energy X-ray absorptiometry scan. BMD and FRAX scores were evaluated at baseline, end of chemotherapy, and 6 months of follow-up.

RESULTS

The median age of the study population was 53 (45-65) years. Early and locally advanced breast cancers were seen in 34 (31.2%) and 75 (68.8%) patients, respectively. The duration of follow-up between two BMD measurements was 6 months. The percentage of decrease in BMD at the lumbar spine, femoral neck, and total hip were - 2.36 ± 2.90, - 2.63 ± 3.79, and - 2.08 ± 2.80, respectively (P-value = 0.0001). The median risk of major osteoporotic fracture (MOF) at 10 years (FRAX score) increased from 1.7 (1.4) to 2.7% (2.4) (P-value = 0.0001).

CONCLUSION

This prospective study in postmenopausal breast cancer women shows a significant association of cytotoxic chemotherapy with the worsening of bone health in terms of BMD and FRAX score.

Hospital based preliminary study on osteoporosis in postmenopausal women

The awareness of osteoporosis has grown world wide in recent years. This silently progressing metabolic bone disease is widely prevalent in India, and osteoporotic fractures are a common cause of morbidity and mortality in adult Indian men and women. Rapid bone loss occurs in postmenopausal women due to hormonal factors which lead to increased risk of fractures. Biochemical markers of bone metabolism are used to assess skeletal turnover. A cross-sectional study of 150 pre- and post menopausal women was carried out at S.D.M College of Medical Sciences and Hospital, Dharwad, during the period of May 2005 to September 2005. The study group consisted of 75 Premenopausal women in the age group of 25-45 years and 75 Postmenopausal women in the age group of 46-65 years. Bone formation markers (Total Calcium, lonised calcium, Phosphorus, Alkaline phosphatase), and bone resorption markers (Urinary Hydroxyproline) were analysed in pre and post menopausal women. Bone formation markers, Total and lonised calcium were significantly decreased (p<0.001) and Alkaline phosphatase was significantly increased (p<0.001) in postmenopausal women compared to premenopausal women. Bone resorption markers, Urinary hydroxyproline excretion was significantly increased (p<0.001) in postmenopausal women. The results from this study suggest that simple, easy, common biochemical markers can still be used to assess the bone turnover in postmenopausal women and hence their risk of developing osteoporosis and fractures.

Genetic and constitutional influences on bone turnover markers: a study of male twin pairs

Biochemical markers of bone turnover originating from type I procollagen synthesis or type I collagen breakdown were examined in men using a classic twin study design based on monozygotic (MZ) and dizygotic (DZ) twins. The aim was to estimate the influence of heredity (genes and shared family childhood elements) and constitutional factors in determining procollagen type I amino-terminal propeptide (PINP), type I collagen carboxy-terminal telopeptide (ICTP), and urinary amino-terminal type I collagen telopeptide (NTx) marker levels in a sample of in 98 MZ and 108 DZ male twin pairs. We are not aware of any prior studies conducted in men that address the influence of genetic factors on bone turnover marker variability. The findings support a dominant role for heredity in the variation of bone resorption marker levels in men, with additive genetic effects explaining two-thirds of the variance in the bone resorption markers NTx and ICTP. Genetic factors may contribute less for PINP, a marker of bone formation. The genetic loci influencing PINP or NTx and body weight/disc axial area, although related in part, appeared to be largely independent, indicating that genetic effects on bone turnover are unlikely to be to a large degree a result of genetic regulation of individual body weight.

Acute effects of a single session of aerobic exercise with or without weight-lifting on bone turnover in healthy young women

This study aimed to investigate the acute effects of exercise on bone turnover and to determine whether brisk walking with or without weight-lifting makes a difference on bone metabolism. Nine healthy women performed two exercise bouts: brisk walking on a treadmill for 30 min (E), and similar exercise carrying 5 kg of weight in a backpack (WE). Serum parathyroid hormone (PTH), osteocalcin (OC), calcitonin (CT), procollagen type 1 carboxy terminal propeptide (PICP), procollagen type 1 amino terminal propeptide (PINP), type 1 collagen carboxy terminal telopeptide (ICTP), total alkaline phosphatase (ALP), and urine deoxypyridinoline (D-Pyr) levels were studied. Resting values served as control. Significant variances were observed only in serum ALP and PTH values. Variances in ALP values within subjects after exercise were statistically significant (analysis of variance in repeated measurements [AVRM], P=0.000). E caused a significant decrease, while WE caused a significant increase in ALP values at the 24th h (Bonferroni pairwise comparisons tests [BPC t-test]: P=0.028, P=0.000, respectively). Variances in PTH values within subjects after exercise were statistically significant (AVRM, P=0.029), while diurnal variation was not significant (P=0.981). E caused significant alterations in PTH levels (an increase at the 30th min, turned towards baseline at the 45th min) (BPC t-test, P=0.007). WE also caused alterations in PTH levels, though insignificant (BPC t-test, P=1.00). Brisk walking for 30 min has stimulating effects on bone turnover by various mechanisms without any additive effect of weight bearing.

[Effect of physical training on the bone tissue and the calcium serum concentration in ovariectomized mice]

PURPOSE

The aim of this study is to evaluate possible morphometric alterations in bone tissue and the calcium serum concentration in ovariectomized mice subjected to physical training.

METHODS

Fifty female mice, aged 90 days, divided into 5 groups (n=10): control (C), pseudo-operated sedentary (POS), pseudo-operated trained (POT), ovariectomized sedentary (OVS) and ovariectomized trained (OVT). Groups OVS and OVT were subjected to an ovariectomy, and groups POS and POT were subjected to a pseudo-surgery. Thirty days after the surgery, groups POT and OVT were subjected to physical training during 05 weeks in ergometer at a speed of 20 m/min. The other animals stayed sedentary at the same period. Afterwards the animals were sacrificed and had blood collected to realize calcium serum dosage and the right femurs were collected to realize a histomorphometric study.

RESULTS

The calcium serum concentration in group OVT was lower than the other groups (p<0.05). The mass of femurs in groups POT and OVT was higher than the group Control (p<0.05). The average density of the osteocytes was higher in group OVS (p<0.05). The average value of the area of the osteocytes showed difference only between groups POS and OVS (p<0.05). There were no differences in the bone length, nor in the osteocytes perimeter.

CONCLUSION

The physical training in part prevented the alterations in the bone tissue due to the ovariectomy and enabled an increase of the bone formation.

The beneficial effect of OST-6 (OsteoCare), a herbomineral formulation, in experimental osteoporosis

OST-6 (OsteoCare), a herbomineral formulation, was evaluated for its inhibitory effect on the progress of bone loss induced by ovariectomy in rats. Ovariectomized (Ovx) rats were administered with OST-6 at 250 and 500 mg/kg b.wt., orally daily for 90 days. On 91st day, ovariectomized rats showed reduced bone mineral content and increased serum alkaline phosphatase levels, excretion of urinary calcium and pyridinium cross-links levels. Histologically, bone sections revealed narrowed and disappearance of trabeculae and widened medullary spaces. The total numbers of Tartrate-resistant acid phosphatase (TRAP) positive cells were significantly increased both in-vivo and in-vitro methods. OST-6, at a dose of 500 mg/kg, significantly improved bone mineral contents, serum alkaline phosphatase levels, reduced the elevated urinary calcium and pyridinium cross-links excretion, number of TRAP positive cells and reversal of the above mentioned histological features. These results indicate the usefulness of OST-6 in the management of osteoporosis in a natural way through herbal resources.

Nitroglycerin therapy is as efficacious as standard estrogen replacement therapy (Premarin) in prevention of oophorectomy-induced bone loss: a human pilot clinical study

Nitric oxide (NO) is known to affect bone metabolism. Previous animal studies have shown that NO donor therapy can prevent ovariectomy (OVX)-induced as well as corticosteroid-induced bone loss. Therefore, we have carried out a 1-year human, randomized, controlled pilot clinical study to assess the efficacy of nitroglycerin (NG) in the prevention of estrogen-deficiency-induced bone loss in women. We observed that NG ointment, when applied to the skin once a day (within 4 weeks of undergoing oophorectomy), mimicked estrogen replacement therapy in prevention of bone loss. The primary outcome of bone mineral density (BMD) was not different in the two groups at the end of 1 year. Urinary N-telopeptide levels were significantly decreased after administration of either estrogen or NG. Although estrogen decreased serum osteocalcin and bone-specific alkaline phosphatase levels, NG therapy significantly increased these two markers of bone formation. Further, it was revealed that for up to 1 year, these doses of NG did not result in tachyphylaxis. This study showed for the first time that NG is as effective as estrogen in preventing bone loss in these surgically induced menopausal women. Additionally, the dose of NG used in this study was three to four times less than that generally used to affect cardiovascular homeostasis. Although in this randomized clinical study only a small number of patients was examined, data are encouraging. If these data hold true in large randomized, controlled clinical trials, then NG could emerge as an efficacious, cost-effective, affordable, safe, and convenient form of therapy (especially as an alternative therapy to hormone-replacement therapy [HRT]) for prevention of postmenopausal bone loss.

Frequency-dependent effect of nitric oxide donor nitroglycerin on bone

Recently, we showed that supplementation with nitric oxide (NO) via donor nitroglycerin (NG) alleviated the ovariectomy and corticosteroid-induced bone loss in rats. In humans, high doses or frequent applications of NG (i.e., for angina) lead to rapid loss of its efficacy in relieving angina. To examine whether there is a similar effect on the loss of efficacy of NG on bone, we examined the frequency-dependent effects of NG on bone mineral density (BMD), bone mass, trabecular bone volumes (BV/TV), and blood pressure in rats. Thirty 7-month-old female Brown Norway rats underwent ovariectomy, and an additional six rats were sham-operated. The ovariectomized rats were treated either with vehicle (ovariectomized control), 17beta-estradiol (E2; positive control), or 0.2 mg NG (via dermal application) once, twice, or three times a day. Before and at the end of the 10-week treatment period, BMD of the lumbar spine was measured by dual-energy X-ray absorptiometric (DXA) scanning and expressed as a percentage change. BMD in ovariectomized rats was significantly lower (-2.5 +/- 2.0%) compared with the sham-operated rats (+6.3 +/- 5.3%; p < 0.01). Estrogen therapy completely abolished the ovariectomy-induced potential bone loss (+5.9 +/- 3.4%). Application of NG once daily also completely prevented (+6.2 +/- 2.8%; p < 0.01) the ovariectomy-induced bone loss (i.e., it was as effective as estrogen). However, the beneficial effects of NG on BMD were significantly reduced with increased frequency of application of NG (+1.9 +/- 2.1%, twice a day and -0.2 +/- 3.3% three times a day). Estrogen or once daily administration of NG preserved femur weights, BV/TV, and decreased urinary deoxypyridinoline levels as expected. However, a higher level of serum osteocalcin and bone-specific alkaline phosphatase levels were maintained only with once daily administration of NG. There were no adverse effects of these doses of NG on blood pressure, but a tendency to lower blood pressure was noticed with increased frequency of NG. These results confirmed our previous findings that NO donors counteract the bone loss associated with estrogen deficiency. However, these beneficial effects of maintaining BMD are lost with increased frequency of NG application.

Biochemical markers of bone turnover

Biochemical markers of bone turnover that are specific to bone allow study of the subtle changes in bone turnover associated with osteoporosis. They have been evaluated in Paget's disease of the bone and chronic renal failure. This review focuses on the use of biochemical markers of bone turnover in osteoporosis. The data in this review period are numerous and varied due to the growing interest in the use of biochemical markers of bone turnover in clinical practice. The data provide support for the use of the newer bone turnover markers for monitoring treatment of osteoporosis, if care is taken to minimize sources of variability.

Practical clinical application of biochemical markers of bone turnover: Consensus of an expert panel

Biochemical markers of bone turnover have emerged as powerful tools to aid in managing osteoporosis. The newer bone markers have been intensively studied for more than a decade. As a result, we can now confidently report their clinical utility in assessing risk of rapid bone loss and fracture, and monitoring therapy in postmenopausal women with or at risk of osteoporosis. In this review, we will provide a comprehensive foundation for this utility. While there are still questions remaining to be answered, bone marker technology has matured to play an essential role in patient management. We will describe, in practical terms, how bone markers can be appropriately incorporated into clinical practice today.