Early changes in serum N-telopeptide and C-telopeptide cross-linked collagen type 1 predict long-term response to alendronate therapy in elderly women

Composition and Properties of Saliva in Patients with Osteoporosis Taking Antiresorptive Drugs

The aim of this study was to examine how the composition and properties of saliva change in people with osteoporosis who have received antiresorptive (AR) treatment, compared to patients with osteoporosis who have not yet received this treatment.

METHODS

The study population consisted of 38 patients with osteoporosis using AR drugs (Group I) and 16 patients with osteoporosis who had never used AR drugs (Group II). The control group consisted of 32 people without osteoporosis. Laboratory tests included determination of pH and concentrations of Ca, PO₄, total protein, lactoferrin, lysozyme, sIgA, IgA, cortisol, neopterin, activity of amylase at rest, and stimulated saliva. The buffering capacity of stimulated saliva was also determined.

RESULTS

There were no statistically significant differences between the saliva of Group I and Group II. No statistically significant correlation was found between the amount of time using AR therapy (Group I) and the tested parameters of the saliva. Significant differences were found between Group I and the control group. The concentrations of PO₄, lysozyme, and cortisol were higher, while concentrations of Ca ions, sIgA, and neopterin were lower, in comparison to the control group. The significant differences between Group II and the control group were smaller, and they concerned only the concentrations of lysozyme, cortisol, and neopterin.

CONCLUSIONS

The saliva of people with osteoporosis subjected to AR therapy and those not subjected to AR therapy did not show statistically significant differences in terms of the examined parameters of the saliva. However, the saliva of patients with osteoporosis taking and not taking AR drugs was significantly different compared to the saliva of the control group.

Metabolic Alterations in Older Women With Low Bone Mineral Density Supplemented With Lactobacillus reuteri

Osteoporosis and its associated fractures are highly prevalent in older women. Recent studies have shown that gut microbiota play important roles in regulating bone metabolism. A previous randomized controlled trial (RCT) found that supplementation with Lactobacillus reuteri ATCC PTA 6475 (L.reuteri) led to substantially reduced bone loss in older women with low BMD. However, the total metabolic effects of L. reuteri supplementation on older women are still not clear. In this study, a post hoc analysis (not predefined) of serum metabolomic profiles of older women from the previous RCT was performed to investigate the metabolic dynamics over 1 year and to evaluate the effects of L. reuteri supplementation on human metabolism. Distinct segregation of the L. reuteri and placebo groups in response to the treatment was revealed by partial least squares‐discriminant analysis. Although no individual metabolite was differentially and significantly associated with treatment after correction for multiple testing, 97 metabolites responded differentially at any one time point between L. reuteri and placebo groups (variable importance in projection score >1 and p value <0.05). These metabolites were involved in multiple processes, including amino acid, peptide, and lipid metabolism. Butyrylcarnitine was particularly increased at all investigated time points in the L. reuteri group compared with placebo, indicating that the effects of L. reuteri on bone loss are mediated through butyrate signaling. Furthermore, the metabolomic profiles in a case (low BMD) and control population (high BMD) of elderly women were analyzed to confirm the associations between BMD and the identified metabolites regulated by L. reuteri supplementation. The amino acids, especially branched‐chain amino acids, showed association with L. reuteri treatment and with low BMD in older women, and may serve as potential therapeutic targets. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

A review of the latest insights into the mechanism of action of strontium in bone

Interest in strontium (Sr) has persisted over the last three decades due to its unique mechanism of action: it simultaneously promotes osteoblast function and inhibits osteoclast function. While this mechanism of action is strongly supported by in vitro studies and small animal trials, recent large-scale clinical trials have demonstrated that orally administered strontium ranelate (SrRan) may have no anabolic effect on bone formation in humans. Yet, there is a strong correlation between Sr accumulation in bone and reduced fracture risk in post-menopausal women, suggesting Sr acts via a purely physiochemical mechanism to enhance bone strength. Conversely, the local administration of Sr with the use of modified biomaterials has been shown to enhance bone growth, osseointegration and bone healing at the bone-implant interface, to a greater degree than Sr-free materials. This review summarizes current knowledge of the main cellular and physiochemical mechanisms that underly Sr's effect in bone, which center around Sr's similarity to calcium (Ca). We will also summarize the main controversies in Sr research which cast doubt on the 'dual-acting mechanism'. Lastly, we will explore the effects of Sr-modified bone-implant materials both in vitro and in vivo, examining whether Sr may act via an alternate mechanism when administered locally.

Randomized clinical trial comparing efficacy and safety of brand versus generic alendronate (Bonmax®) for osteoporosis treatment

Introduction

Although the same efficacy and tolerability are anticipated due to both drugs containing the same active ingredients, comparative studies between brand and generic alendronate are limited. Accordingly, the objective of this study was to compare efficacy and safety between brand alendronate and a recently introduced generic alendronate drug.

Methods

A total of 140 postmenopausal women or men aged older than 50 years who met the indications for osteoporosis treatment were randomized to receive either generic (Bonmax^®) or brand alendronate (Fosamax^®) 70 mg/week over a 12-month period during the May 2014 to June 2015 study period. Endpoints included bone mineral density (BMD) changes at the lumbar spine, total hip, and femoral neck; percentage of patients with predefined levels of change in total hip and lumbar spine BMD at 12 months; and, changes in biochemical bone markers at 3, 6, and 12 months. Tolerability was evaluated by patient self-reporting of adverse experiences.

Results

At 12 months post-treatment, BMD significantly increased at all sites in both groups. There were no differences in BMD percentage changes or the number of patients with stable or increased BMD after 1 year between groups. No significant differences in the amount of biochemical bone marker reduction or incidence of adverse events were observed between groups.

Conclusions

Generic and brand alendronate produced similar gains in BMD and reduction in bone turnover markers. Both medicadoitions were also equally well-tolerated. Based on these findings, generic alendronate (Bonmax^®) is a viable alternative to the original brand of alendronate.

Trial registration

ClinicalTrials.gov NCT02371252

Morning vs evening dosing of the cathepsin K inhibitor ONO-5334: effects on bone resorption in postmenopausal women in a randomized, phase 1 trial

The cathepsin K inhibitor, ONO-5334, improves bone mineral density in postmenopausal women with osteoporosis. The effects of morning versus evening administration of ONO-5334 were investigated by measuring bone turnover marker levels in healthy postmenopausal women. Morning administration of ONO-5334 showed a more consistent suppressive effect on bone resorption than evening administration.

INTRODUCTION

Bone turnover is thought to be subject to circadian variation, and the efficacy of osteoporosis treatments may be optimized by regulating the time of dosing. This study assessed whether evening administration of the cathepsin K inhibitor, ONO-5334, had a differential effect on the bone turnover marker, C-terminal telopeptide of type I collagen (CTX-I), compared with morning administration.

METHODS

This was a single-center, single blind crossover study. Fourteen healthy postmenopausal women were assigned to receive ONO-5334 150 mg once daily for 5 days in each period; they were randomized to receive either evening doses in the first period and morning doses in the second or vice versa. Serum and urinary levels of CTX-I were measured throughout the study.

RESULTS

Both regimens showed similar patterns of reduction in serum and urinary CTX-I; however, CTX-I suppression was more consistently >60% over 24 h following morning administration. Morning administration led to 6% greater suppression of 24-h serum CTX-I area under the effect curve (AUE; 69 vs 63%; P < .05) and 7% greater suppression of urinary CTX-I/creatinine AUE (93 vs 86%; P < .01) than evening administration. Higher plasma ONO-5334 concentrations were observed between 12 and 24 h postdose following morning administration, with mean trough concentrations for the morning and evening regimens at 9.4 and 4.0 ng/mL, respectively. There were no safety findings of concern.

CONCLUSION

Morning dosing of ONO-5334 is more efficacious at reducing markers of bone turnover in healthy postmenopausal women than evening dosing.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01384188 , registered on June 27, 2011 EudraCT: 2008-006284-37.

Prevention of bone loss with risedronate in breast cancer survivors: a randomized, controlled clinical trial

In postmenopausal women with low bone mass and hormone-receptor-positive breast cancer on an aromatase inhibitor, risedronate maintained skeletal health assessed by bone density and turnover markers. Women with the greatest decreases in bone turnover markers at 12 months had the greatest increases in bone density at 24 months.

INTRODUCTION

Aromatase inhibitors (AIs), adjuvant endocrine therapy for postmenopausal women with hormone-receptor-positive breast cancer, are associated with bone loss and fractures. Our objectives were to determine if (1) oral bisphosphonate therapy can prevent bone loss in women on an AI and (2) early changes in bone turnover markers (BTM) can predict later changes in bone mineral density (BMD).

METHODS

We conducted a 2-year double-blind, placebo-controlled, randomized trial in 109 postmenopausal women with low bone mass on an AI (anastrozole, letrozole, or exemestane) for hormone-receptor-positive breast cancer. Participants were randomized to once weekly risedronate 35 mg or placebo, and all received calcium plus vitamin D. The main outcome measures included BMD, BTM [carboxy-terminal collagen crosslinks (CTX) and N-terminal propeptide of type 1 procollagen (P1NP)], and safety.

RESULTS

Eighty-seven percent completed 24 months. BMD increased more in the active treatment group compared to placebo with an adjusted difference at 24 months of 3.9 ± 0.7 percentage points at the spine and 3.2 ± 0.5 percentage points at the hip (both p < 0.05). The adjusted difference between the active treatment and placebo groups were 0.09 ± 0.04 nmol/LBCE for CTX and 23.3 ± 4.8 μg/mL for P1NP (both p < 0.05). Women with greater 12-month decreases in CTX and P1NP in the active treatment group had a greater 24-month increase in spinal BMD (p < 0.05). The oral therapy was safe and well tolerated.

CONCLUSION

In postmenopausal women with low bone mass and breast cancer on an AI, the oral bisphosphonate risedronate maintained skeletal health.

Comparing tolerability and efficacy of generic versus brand alendronate: a randomized clinical study in postmenopausal women with a recent fracture

Introduction

An increasing number of generic alendronate formulations have become available. Although expected to have the same tolerability and efficacy, head-to head comparison of generic and brand alendronate was never performed. Therefore, we compared the tolerability and efficacy of generic and brand alendronate.

Methods

In a randomized double-blinded single centre cross-over study in 37 postmenopausal women (mean age 65.4±6.4 years) with osteoporosis were treated with generic and branded alendronate during 24 (2x12) weeks. Tolerance was evaluated by the Gastro intestinal Symptom Rating Scale (GSRS) and self-reported side effects. Efficacy was assessed by serum bone turnover markers, carboxy terminal telopeptide (CTX) and procollagen type I N-terminal propeptide (PINP). No wash out period was allowed (ethical reasons). Because of possible carry over effect only data of the first 12 weeks were analyzed using linear mixed models.

Results

There were no significant differences in overall tolerance (GSRS) between treatment groups. However, for subscale abdominal pain, patients using generic had a significantly higher mean GSRS score at week 4 (estimated mean difference (B): 0.40; 95%CI: 0.05 to 0.74, p = 0.024). The level of bone turnover markers significantly decreased over 12 weeks of follow-up for generic and branded alendronate (p < 0.001). Mean level of CTX was significantly lower with branded at week 4 (B: 121.3; 95%CI: 52.0 to 190.5), but not at week 12 (B: 53.6; 95%CI:-3.7 to 110.9). No significant differences were found for PINP at week 4 or 12.

Conclusions

Bone turnover markers were significantly reduced with branded and generic alendronate. With branded, CTX was significantly lower at 4 weeks. Generic caused significantly higher abdominal pain scores in the first 4 weeks of treatment. Therefore, generic alendronate may not have the same tolerability and efficacy as branded alendronate in the first weeks after starting treatment in patients with a recent fracture.

Trial Registration

Dutch Trial Register NTR number 1867 http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1867

Dental complications and management of patients on bisphosphonate therapy: A review article

Bisphosphonates are group of drugs that inhibit bone resorption and are used to treat a range of pathologies including Paget's disease, osteoporosis, multiple myeloma and metastasis associated with breast or prostate cancer. The most common complication in patients on bisphosphonate therapy is osteonecrosis of jaw (ONJ) which can occur after any surgical dental procedure and the risk for the development of osteonecrosis of jaw is higher in patients receiving intravenous bisphosphonate therapy than in patients receiving oral bisphosphonate therapy. Typical presentation is in the form of non-extraction socket, presence of exposed bone, gingival swelling or purulent discharge, when local debridement and antibiotics are ineffective. At present, there is no effective treatment for bisphosphonate induced osteonecrosis, so prevention is extremely important. Maximum precautions should be taken in patients who are at the risk of development of ONJ especially when any dental surgical procedure like extractions, retrograde apicoectomies, periodontal surgery and implant placement is contemplated. Dentists and oral or maxillofacial surgeon must keep up to date with the latest approaches or guidelines to prevention and the risk factors, particularly when treating patients who are on bisphosphonates, or who will be taking bisphosphonates.

National Bone Health Alliance Bone Turnover Marker Project: current practices and the need for US harmonization, standardization, and common reference ranges

This position paper reviews how the National Bone Health Alliance (NBHA) will execute a project to help assure health professionals of the clinical utility of bone turnover markers; the current clinical approaches concerning osteoporosis and the status and use of bone turnover markers in the USA; the rationale for focusing this effort around two specific bone turnover markers; the need to standardize bone marker sample collection procedures, reference ranges, and bone turnover marker assays in clinical laboratories; and the importance of harmonization for future research of bone turnover markers.

INTRODUCTION

Osteoporosis is a major global health problem, with the prevalence and incidence of osteoporosis for at-risk populations estimated to be 44 million Americans. The potential of bone markers as an additional tool for health care professionals to improve patient outcomes and impact morbidity and mortality is crucial in providing better health care and addressing rising health care costs. This need to advance the field of bone turnover markers has been recognized by a number of organizations, including the International Osteoporosis Foundation (IOF), National Osteoporosis Foundation, International Federation of Clinical Chemistry, and Laboratory Medicine (IFCC), and the NBHA.

METHODS

This position paper elucidates how this project will standardize bone turnover marker sample collection procedures in the USA, establish a USA reference range for one bone formation (serum procollagen type I N propeptide, s-PINP) and one bone resorption (serum C-terminal telopeptide of type I collagen, s-CTX) marker, and standardize bone turnover marker assays used in clinical laboratories. This effort will allow clinicians from the USA to have confidence in their use of bone turnover markers to help monitor osteoporosis treatment and assess future fracture risk. This project builds on the recommendations of the IOF/IFCC Bone Marker Standards Working Group by developing USA reference standards for s-PINP and s-CTX, the markers identified as most promising for use as reference markers.

RESULTS

The goals of this project will be realized through the NBHA and will include its governmental, academic, for-profit, and non-profit sector stakeholders as well as major academic and commercial laboratories. Upon completion, a parallel effort will be pursued to make bone turnover marker measurements reliable and accepted by all health care professionals for facilitating treatment decisions and ultimately be reimbursed by all health insurance payers.

CONCLUSIONS

Successful completion of this project will help assure health professionals from the USA of the clinical utility of bone turnover markers and ties in with the parallel effort of the IOF/IFCC to develop worldwide bone turnover reference ranges.

Study of serum CTX in 50 oral surgical patients treated with oral bisphosphonates

Objectives: To determine whether there is a relationship between the total BP dose administered and the variations in serum CTX concentration. Study design: The study included 50 patients requiring dental implant surgery and treated with oral BPs, seen in an Oral Surgery and Implantology Unit between January 2007 and June 2009. The patients were divided into two groups: those in which the medication was not suspended before obtaining the laboratory test sample, and those patients referred from other dental clinics in which BPs was suspended before reporting to our Unit. The total drug dosage administered and the total dose per kilogram body weight were evaluated for comparison with serum CTX. The data obtained were correlated to the osteonecrosis risk table developed by Marx et al. in 2007. Results: There were no significant differences between the two groups in relation to the total administered dose and the dose in mg/kg b.w. Likewise, in both groups no relationship was observed between the serum CTX value and the total administered dose or the dose in mg/kg b.w. No differences were found between the two patient groups regarding chemical osteonecrosis risk based on the criteria of Marx et al. Conclusions: No relationship was observed between the oral BP dose administered (total dose or expressed in mg/kg b.w.) and serum CTX concentration, and suspension of the medication did not influence the serum CTX levels.

Key words:Serum CTX, osteonecrosis, oral bisphosphonates.

Absorption of silicon from artesian aquifer water and its impact on bone health in postmenopausal women: a 12 week pilot study

Background

Decreased bone mineral density and osteoporosis in postmenopausal women represents a growing source of physical limitations and financial concerns in our aging population. While appropriate medical treatments such as bisphosphonate drugs and hormone replacement therapy exist, they are associated with serious side effects such as osteonecrosis of the jaw or increased cardiovascular risk. In addition to calcium and vitamin D supplementation, previous studies have demonstrated a beneficial effect of dietary silicon on bone health. This study evaluated the absorption of silicon from bottled artesian aquifer water and its effect on markers of bone metabolism.

Methods

Seventeen postmenopausal women with low bone mass, but without osteopenia or osteoporosis as determined by dual x-ray absorptiometry (DEXA) were randomized to drink one liter daily of either purified water of low-silicon content (PW) or silicon-rich artesian aquifer water (SW) (86 mg/L silica) for 12 weeks. Urinary silicon and serum markers of bone metabolism were measured at baseline and after 12 weeks and analyzed with two-sided t-tests with p < 0.05 defined as significant.

Results

The urinary silicon level increased significantly from 0.016 ± 0.010 mg/mg creatinine at baseline to 0.037 ± 0.014 mg/mg creatinine at week 12 in the SW group (p = 0.003), but there was no change for the PW group (0.010 ± 0.004 mg/mg creatinine at baseline vs. 0.009 ± 0.006 mg/mg creatinine at week 12, p = 0.679). The urinary silicon for the SW group was significantly higher in the silicon-rich water group compared to the purified water group (p < 0.01). NTx, a urinary marker of bone resorption did not change during the study and was not affected by the silicon water supplementation. No significant change was observed in the serum markers of bone formation compared to baseline measurements for either group.

Conclusions

These findings indicate that bottled water from artesian aquifers is a safe and effective way of providing easily absorbed dietary silicon to the body. Although the silicon did not affect bone turnover markers in the short-term, the mineral's potential as an alternative prevention or treatment to drug therapy for osteoporosis warrants further longer-term investigation in the future.

Trial Registration

ClinicalTrials.gov Identifier: NCT01067508

Plasma inflammatory mediators associated with bone metabolism in COPD

ABSTRACT The association of osteoporosis with COPD is well established, but the relationship between systemic inflammatory mediators and bone metabolism has not been explored. Plasma samples from 40 COPD patients awaiting lung transplantation were analyzed for 27 inflammatory mediators using a multiplex protein array. C-telopeptide type I collagen (CTx), a marker of bone resorption, was measured with ELISA, and N-terminal procollagen propeptide (P1NP), a marker of bone formation, was ascertained with a radioimmunoassay. Associations between inflammatory mediators versus CTx and P1NP with adjustments for steroid and bisphosphonate use were determined. Mean age was 59 years (+/- 6) and FEV(1) was 23.5% (+/- 8.3%) predicted. Ninety-five percent of the subjects had low bone mineral density measured by dual x-ray absorptiometry (DXA). Tumor necrosis factor alpha and interleukin 4 were positively associated with CTx and P1NP. RANTES and eotaxin were inversely associated with CTx and P1NP. Interleukin 2 and interferon gamma were also directly associated with P1NP. Biologically plausible systemic mediators are associated with bone metabolism in patients with severe COPD, offering potential insight into risk factors and underlying mechanisms of bone disease. Furthermore, they may be useful in monitoring disease activity, and serve as targets for biological therapy.

Prediction of changes in bone mineral density in postmenopausal women treated with once-weekly bisphosphonates

BACKGROUND

In clinical practice, bone mineral density (BMD) determined by dual-energy x-ray absorptiometry is used to monitor response to osteoporosis therapy. However, 1 to 2 yr are usually required to assess patients' BMD responses. The possibility of earlier indicators of a response or nonresponse to treatment, such as changes in bone turnover markers (BTMs), is of interest to physicians and patients.

METHODS

In this post hoc analysis of women treated with once-weekly bisphosphonates, we examined the association of tertile percentage change from baseline in BTMs at 3 or 6 months and association of several baseline clinical characteristics with 24-month percentage change from baseline in BMD and with percentage of patients showing BMD nonresponse (defined as BMD loss at two or more of four sites) at 24 months. Multivariable analysis was performed to determine which factors were independently associated with BMD nonresponse.

RESULTS

Patients in the tertile with the greatest decrease in each of the BTMs had the greatest mean increase in BMD and the lowest percentage of BMD nonresponders at 24 months. Several characteristics were independently associated with BMD nonresponse, including smaller 3-month reductions from baseline in serum C-terminal telopeptide of type 1 collagen, bone-specific alkaline phosphatase, and N-terminal propeptide of type 1 procollagen; younger age of menopause; a family history of osteoporosis; and higher baseline trochanteric BMD. Baseline BTMs were not predictive of 24-month BMD response to therapy. The strongest associations were for changes in BTMs with treatment.

CONCLUSION

In groups of patients, short-term changes in markers of bone turnover appear to be predictors of longer term BMD response and nonresponse to bisphosphonate therapy.

Bisphosphonate-related osteonecrosis of the jaws: an update on clinical, pathological and management aspects

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is mainly observed in patients with multiple myeloma and bone metastasis from solid tumors receiving iv bisphosphonate therapy. The reported incidence of BRONJ is significantly higher with the iv preparations zoledronic acid and pamidronate while the risk appears to be minimal for patients receiving oral bisphosphonates. Currently available published incidence data for BRONJ are based on retrospective studies and estimates of cumulative incidence range from 0.8 to 12%. The mandible is more commonly affected than the maxilla (2:1 ratio), and 60-70% of cases are preceded by a dental surgical procedure. The signs and symptoms that may occur before the appearance of clinical evident osteonecrosis include changes in the health of periodontal tissues, non-healing mucosal ulcers, loose teeth and unexplained soft-tissue infection. Although the definitive role of bisphosphonates remains to be elucidated, the inhibition of physiologic bone remodeling and angiogenesis by these potent drugs impairs the regenerative capacity of the bone causing the development of BRONJ. Tooth extraction as a precipitating event is a common observation. The significant benefits that bisphosphonates offer to patients clearly surpass the risk of potential side effects; however, any patient for whom prolonged bisphosphonate therapy is indicated, should be provided with preventive dental care in order to minimize the risk of developing this severe condition. This article provides an update review of current knowledge about clinical, pathological and management aspects of BRONJ.

Bone turnover in elderly men: relationships to change in bone mineral density

Background

It is not clear whether bone turnover markers can be used to make inference regarding changes in bone mineral density (BMD) in untreated healthy elderly men. The present study was designed to address three specific questions: (i) is there a relationship between bone turnover markers and femoral neck BMD within an individual; (ii) is there a relationship between baseline measurements of bone turnover markers and subsequent change in BMD; and (iii) is there a relationship between changes in bone turnover markers and changes in femoral neck BMD?

Methods

The present study was part of the on-going Dubbo Osteoporosis Epidemiology Study, which was designed as a prospective investigation. Men who had had at least 3 sequential visits with serum samples available during follow-up were selected from the study population. Serum C-terminal telopeptide of type I collagen (sICTP), N-terminal propeptide of type I collagen (sPINP) and femoral neck BMD were measured by competitive radioimmunoassays. Femoral neck bone mineral density (BMD) was measured by a densitometer (GE Lunar Corp, Madison, WI). Various mixed-effects models were used to assess the association between the markers and changes in BMD.

Results

One hundred and one men aged 70 ± 4.1 years (mean ± SD) met the criteria of selection for analysis. On average, sPINP decreased by 0.7% per year (p = 0.026), sICTP increased by 1.7% per year (p = 0.0002), and femoral neck BMD decreased by 0.4% per year (p < 0.01). Within-subject analysis indicated that changes in BMD were significantly associated with changes in sPINP (p = 0.022), but not with changes in sICTP (p = 0.84). However, neither baseline sPINP (p = 0.50) nor baseline sICTP (p = 0.63) was associated with subsequent changes in BMD. Moreover, changes in BMD were not significantly associated with previous changes in sPINP (p = 0.13) or sICTP (p = 0.95).

Conclusion

These results suggest that in elderly men of Caucasian background, changes in sPINP were inversely related to changes in BMD within an individual. However, neither sPINP nor sICTP was sufficiently sensitive to predict the rate of change in BMD for a group of individuals or for an individual.

An increase in dietary n-3 fatty acids decreases a marker of bone resorption in humans

Human, animal, and in vitro research indicates a beneficial effect of appropriate amounts of omega-3 (n-3) polyunsaturated fatty acids (PUFA) on bone health. This is the first controlled feeding study in humans to evaluate the effect of dietary plant-derived n-3 PUFA on bone turnover, assessed by serum concentrations of N-telopeptides (NTx) and bone-specific alkaline phosphatase (BSAP). Subjects (n = 23) consumed each diet for 6 weeks in a randomized, 3-period crossover design: 1) Average American Diet (AAD; [34% total fat, 13% saturated fatty acids (SFA), 13% monounsaturated fatty acids (MUFA), 9% PUFA (7.7% LA, 0.8% ALA)]), 2) Linoleic Acid Diet (LA; [37% total fat, 9% SFA, 12% MUFA, 16% PUFA (12.6% LA, 3.6% ALA)]), and 3) alpha-Linolenic Acid Diet (ALA; [38% total fat, 8% SFA, 12% MUFA, 17% PUFA (10.5% LA, 6.5% ALA)]). Walnuts and flaxseed oil were the predominant sources of ALA. NTx levels were significantly lower following the ALA diet (13.20 +/- 1.21 nM BCE), relative to the AAD (15.59 +/- 1.21 nM BCE) (p < 0.05). Mean NTx level following the LA diet was 13.80 +/- 1.21 nM BCE. There was no change in levels of BSAP across the three diets. Concentrations of NTx were positively correlated with the pro-inflammatory cytokine TNFalpha for all three diets. The results indicate that plant sources of dietary n-3 PUFA may have a protective effect on bone metabolism via a decrease in bone resorption in the presence of consistent levels of bone formation.

Pamidronate distribution in pediatric renal and rheumatologic patients

OBJECTIVE

To evaluate the distribution and elimination of pamidronate in a population of pediatric patients with renal and rheumatologic disease.

METHODS

Pamidronate whole blood levels were collected for the first 4 h after first exposure in 7 patients. The relationship between the rate of urinary excretion of pamidronate and bone formation or resorption was examined in 18 patients while receiving pamidronate at a total dose of 1 mg/kg/dose infused intravenously over a 4-h period. The urinary pamidronate clearances were correlated with renal function, calcium levels and measures of bone formation and resorption.

RESULTS

Pamidronate levels reached steady state concentrations of 0.9-1.5 microg/ml within 30 min and the clearance of the drug (mean+/-SE) from blood was 180.0+/-64.2 ml/kg/h with an elimination half-life of less than 1 h. The mean urinary excretion of 31.5+/-2.2% of the administered dose indicated that about 68% of the drug was incorporated into bone, confirming the uptake of pamidronate into bone was similar in pediatric patients compared to that previously reported for adults. Bone specific alkaline phosphatase, which is a marker for bone growth and formation, had significant correlation with the uptake of pamidronate into bone (p=0.002). No correlation was demonstrated with a marker for bone resorption (urinary N-telopeptide/creatinine ratio), or with creatinine clearance or calciuria when assessed 2 months after treatment.

CONCLUSION

Pamidronate at a dose of 1 mg/kg/dose every 2 months appears safe in the short term for pediatric patients, achieves relatively low whole blood pamidronate levels, and has similar skeletal uptake of pamidronate compared to adults.

Efficacy and tolerability of once-weekly administration of 17.5 mg risedronate in Japanese patients with involutional osteoporosis: a comparison with 2.5-mg once-daily dosage regimen

In this multicenter, randomized, double-blind controlled trial, the efficacy and safety of once-weekly dosing with 17.5 mg risedronate was compared with once-daily dosing with 2.5 mg risedronate in Japanese patients with involutional osteoporosis. A total of 496 patients were randomized to receive either once-weekly (n = 249) or once-daily (n = 247) treatment. All patients were supplemented with 200 mg/day calcium. Following 48 weeks of treatment, the mean (+/-SD) percent changes, from baseline, in the bone mineral density of the lumbar spine (L2-L4 BMD) in the once-weekly and once-daily treatment groups were 5.36 +/- 4.27% and 5.87 +/- 4.47%, respectively. The difference between the groups was -0.5% (95% confidence interval: -1.35% to 0.35%), demonstrating that the effect on BMD of once-weekly treatment was not inferior to that of once-daily treatment. The time-course reductions in biochemical markers of bone resorption (urinary N- and C-telopeptide of type I collagen) and bone formation (bone-specific alkaline phosphatase) were similar for the two dosing regimens. There were no differences in the incidence of new vertebral fractures or the worsening of existing fractures between the once-weekly (2.2%) and once-daily (2.7%) dosing regimens. No significant differences were observed between the two dosing regimens in the incidence or the type of adverse events. However, 10.1% of the patients in the once-daily group withdrew due to adverse events as compared to 5.2% in the once-weekly group. Moreover, drug-related adverse events, including upper gastrointestinal disorders and abnormal changes in laboratory parameters, tended to be less in the once-weekly dosing regimen than in the once-daily dosing regimen. In conclusion, once-weekly oral dosing with 17.5 mg risedronate was well tolerated in Japanese osteoporotic patients, and showed equivalent efficacy to once-daily oral dosing with 2.5 mg risedronate. This once-weekly regimen is expected to provide a more convenient therapeutic option as an alternative to daily dosing and to enhance patient compliance in long-term therapy for osteoporosis.