Safety of parathyroid hormone for the treatment of osteoporosis

Delayed and significant hypercalcaemia due to teriparatide therapy: a case report and review

INTRODUCTION

Transient hypercalcaemia due to teriparatide occurs in up to 11% of patients though delayed hypercalcaemia (> 24 h post injection) is rare. We report the case of a female who developed significant delayed hypercalcaemia after teriparatide treatment for osteoporosis and review other cases in the literature to date.

CASE REPORT

A 72-year-old female on teriparatide for the treatment of osteoporosis was found to have hypercalcaemia (3.30 mmol/l) on routine testing approximately 3 months after starting therapy. Serum calcium pretreatment was normal at 2.39 mmol/l. She was admitted to the hospital for investigations which identified a serum 25-hydroxyvitamin D of 94 nmol/l, a low parathyroid hormone of 6.0 pg/ml, and normal test results for 1,25 dihydroxyvitamin D (115 pmol/l), parathyroid hormone-related peptide (< 1.4 pmol/ml), serum electrophoresis and angiotensin-converting enzyme (39 IU/l). CT abdomen, pelvis, and thorax revealed no evidence of malignancy and an isotope bone scan ruled out skeletal metastases. Serum calcium normalised (2.34 mmol/l) several days after stopping teriparatide and calcium supplements and administering intravenous fluid. On restarting teriparatide, delayed hypercalcaemia reoccurred and treatment was switched to denosumab.

DISCUSSION

Delayed moderate to severe hypercalcaemia (serum calcium > 3.0 mmol/l) due to teriparatide is rare but may lead to therapy withdrawal. The underlying predisposing risk factors remain unclear and highlight the importance of a routine serum calcium assessment on therapy.

Microwave-assisted synthesis of novel steroidal heterocyclic analogs as potent inhibitors of RANKL-induced osteoclastogenesis

Osteoporosis is a significant public health issue in our aging population. It is an excessive bone resorption condition brought on by osteoclastogenesis, which makes bones more brittle. In the present work, a series of novel heterosteroidal derivatives have been synthesized using the microwave technique and were evaluated as antiosteoclastogenic agents. The structures of the newly synthesized compounds have been confirmed using analytical and spectral data. The antiosteoclastogenic activity of the newly synthesized compounds was estimated in vitro against osteoclast-differentiated cells from the RAW 264.7 cell line. The pregnenolone dimer 10, the pyridinotestosterone derivative 2, and the phenylnicotinonitrile pregnenolone derivative 8a attained the most promising antiosteoclastogenic activity displaying IC50 (the half maximal inhibitory concentration) values of 5.45 ± 5.30, 11.88 ± 2.09, and 13.40 ± 3.00 µM, respectively, in comparison with dimethyl itaconate (IC50  = 17.76 ± 3.20 µM) and alendronate (IC50  = 4.48 ± 1.89 µM) as reference compounds. Finally, an in silico ADME (Absorption, Distribution, Metabolism, and Excretion) study was conducted to evaluate the synthesized compounds' pharmacokinetic and drug-likeness properties. The results manifested that almost all the investigated compounds' properties were compatible with the specified optimal range, which indicates their reassuring pharmacokinetic properties.

Exploring the mechanism of traditional Chinese medicine in regulating gut-derived 5-HT for osteoporosis treatment

Osteoporosis is a systemic bone disease characterized by an imbalance in the relationship between osteoblasts, osteocytes, and osteoclasts. This imbalance in bone metabolism results in the destruction of the bone's microstructure and an increase in bone brittleness, thereby increasing the risk of fractures. Osteoporosis has complex causes, one of which is related to the dysregulation of 5-hydroxytryptamine, a neurotransmitter closely associated with bone tissue metabolism. Dysregulation of 5-HT directly or indirectly promotes the occurrence and development of osteoporosis. This paper aims to discuss the regulation of 5-HT by Traditional Chinese Medicine and its impact on bone metabolism, as well as the underlying mechanism of action. The results of this study demonstrate that Traditional Chinese Medicine has the ability to regulate 5-HT, thereby modulating bone metabolism and improving bone loss. These findings provide valuable insights for future osteoporosis treatment.

Synthesis and Biological Evaluation of Heterocyclic Ring-Fused 20(S)-Protopanaxadiol Derivatives as Potent Antiosteoporosis Agents

A series of heterocyclic ring-fused derivatives of 20(S)-protopanaxadiol (PPD) were synthesized and evaluated for their inhibitory effects on RANKL-induced osteoclastogenesis. Among these compounds, 33 (SH491, IC50 = 11.8 nM) showed the highest potency with 100% inhibition at 0.1 μM and 44.4% inhibition at an even lower concentration of 0.01 μM, which was much more potent than the lead compound PPD (IC50 = 10.3 μM). Cytotoxicity tests indicated that the inhibitory effect of these compounds on RANKL-induced osteoclast differentiation was not due to their cytotoxicity. Interestingly, SH491 also exhibited a notable impact on the osteoblastogenesis of MC3T3-E1 preosteoblasts. Mechanistic studies revealed that SH491 inhibits the expression of osteoclastogenesis-related marker genes and proteins, including TRAP, CTSK, MMP-9, and ATPase v0d2. In vivo, SH491 could dramatically decrease the ovariectomy-induced osteoclast activity and relieve osteoporosis obviously. Thus, these PPD derivatives could be served as promising leads for the development of novel antiosteoporosis agents.

Assessing the incidence of osteosarcoma among teriparatide-treated patients using linkage of commercial pharmacy and state cancer registry data, contributing to the removal of boxed warning and other labeling changes

BACKGROUND

Teriparatide, a recombinant human parathyroid hormone analogue, is associated with increased bone mineral density and a decreased risk of fractures. A dose-dependent increase in the incidence of osteosarcoma was observed in toxicology studies conducted in rats. The primary objective of this study was to estimate the incidence of osteosarcoma over a 10-year period among teriparatide-treated patients versus patients unexposed to teriparatide with osteoporosis and patients in the general population using national pharmacy dispensing data linked with data from participating state cancer registries (SCRs) in the US.

METHODS

Patients aged 18 years or older with a dispensed teriparatide prescription formed two different cohorts: Teriparatide-Osteoporosis (Teriparatide-OP) was formed by matching teriparatide patients to unexposed patients with osteoporosis and Teriparatide-General Population (Teriparatide-GP) was formed by matching teriparatide patients to general population patients with a dispensed prescription for a medication other than teriparatide. Matching was performed using select demographics and other variables. Study cohorts were linked to SCR data to ascertain osteosarcoma status. To account for missing outcome data from non-participating SCRs, two analytic approaches were used: the first adjusted the person-time at-risk using a coverage fraction and the second restricted the analyses to patients from states with participating SCRs.

RESULTS

There were 18 osteosarcoma cases across four study cohorts: the same three cases in the Teriparatide-OP and Teriparatide-GP cohorts, six cases in the Osteoporosis cohort, and nine cases in the General Population cohort. For the analysis using the coverage fraction the incidence rate ratio (IRR) comparing the Teriparatide-OP and Teriparatide-GP cohorts to the Osteoporosis and General Population cohorts was 1.0 (95% CI: 0.2, 4.5) and 1.3 (95% CI: 0.2, 5.1), respectively. When restricting the analysis to patients from states with participating SCRs, the IRR was 0.6 (95% CI: 0.1, 3.6) and 0.8 (95% CI 0.1, 4.0), respectively.

CONCLUSION

The estimates of association between teriparatide and osteosarcoma were imprecise due to the small number of observed osteosarcoma cases. However, the incidence of osteosarcoma observed in each study cohort was within the expected range given background rates for the US general population. The evidence generated by this study, in conjunction with other real-world studies evaluating the risk of osteosarcoma, was used to support changes to the US teriparatide label (including removal of the black box warning regarding potential risk of osteosarcoma) and expand treatment options for patients with osteoporosis.

Inhibition of Cdk5 Ameliorates Skeletal Bone Loss in Glucocorticoid-Treated Mice

Glucocorticoids (GCs) are widely used to treat inflammatory diseases. However, their long-term use leads to glucocorticoid-induced osteoporosis, increasing morbidity and mortality. Both anabolic and anti-resorptive drugs are used to counteract GC-induced bone loss, however, they are expensive and/or have major side effects. Therefore, identifying new targets for cost-effective, small-molecule inhibitors is essential. We recently identified cyclin-dependent kinase 5 (Cdk5) as a suppressor of osteoblast differentiation and showed that its inhibition with roscovitine promoted osteoblastogenesis, thus improving the skeletal bone mass and fracture healing. Here, we assessed whether Cdk5 knockdown or inhibition could also reverse the GC-mediated suppression of osteoblast differentiation, bone loss, and fracture healing. We first demonstrated that Cdk5 silencing abolished the dexamethasone (Dex)-induced downregulation of alkaline phosphatase (Alp) activity, osteoblast-specific marker gene expression (Runx2, Sp7, Alpl, and Bglap), and mineralization. Similarly, Cdk5 inhibition rescued Dex-induced suppression of Alp activity. We further demonstrated that Cdk5 inhibition reversed prednisolone (Pred)-induced bone loss in mice, due to reduced osteoclastogenesis rather than improved osteoblastogenesis. Moreover, we revealed that Cdk5 inhibition failed to improve Pred-mediated impaired fracture healing. Taken together, we demonstrated that Cdk5 inhibition with roscovitine ameliorated GC-mediated bone loss but did not reverse GC-induced compromised fracture healing in mice.

Ziyuglycoside I Upregulates RUNX2 through ERK1/2 in Promoting Osteoblast Differentiation and Bone Mineralization

Sanguisorba officinalis L. (Rosaceae) is a perennial herbaceous plant and its roots have been used as an important traditional medicine for over 2000 years. Ziyuglycoside I (Ziyu), an active compound isolated from the roots of S. officinalis L., has shown biological effects such as anti-oxidant, antiviral, and antiwrinkle activities. This study aimed to elucidate the underlying mechanisms of action of Ziyu on cytotoxicity, migration, and differentiation of pre-osteoblasts. Herein, at concentrations ranging from 1 to 100 [Formula: see text]M, Ziyu was not cytotoxic against pre-osteoblasts. Alkaline phosphatase activity assay and staining, and migration assay showed that Ziyu increased cell migration and promoted early osteoblast differentiation, followed by the enhancement of mineralized nodule formation in a dose-dependent manner, as indicated by Alizarin Red S staining. In addition, Ziyu increased the protein levels of runt-related transcription factor 2 (RUNX2) during osteoblast differentiation, whereas it did not affect the phosphorylation of Smad1/5/8 and GSK3b and expression of [Formula: see text]-catenin. Ziyu also activated ERK1/2 and mitogen-activated protein kinase during osteoblast differentiation, and ERK1/2 inhibitor attenuated Ziyu-mediated RUNX2 expression and nuclear accumulation. Furthermore, Ziyu-mediated early and late osteoblast differentiation was significantly suppressed by the inhibition of ERK1/2, which was accompanied by attenuation in the mRNA levels of osteoblast-related genes including bone sialoprotein, osteopontin, and osteocalcin. Taken together, the findings of this study provide evidence that Ziyu promotes cell migration, osteoblast differentiation, and bone mineralization and suggest a potential role for Ziyu in the treatment of bone diseases.

Assessing the incidence of osteosarcoma among teriparatide users based on Medicare Part D and US State Cancer Registry Data

Purpose

During preclinical testing, teriparatide caused a dose‐dependent increase in the incidence of osteosarcoma in rats. This study compared the incidence rate of osteosarcoma among patients aged ≥65 years treated with teriparatide vs a matched‐comparator cohort.

Methods

This population‐based comparative‐cohort study matched exposure details for each teriparatide user, identified via Medicare Part D prescription claims, and up to four comparators based on age, sex, zip code, date of claim for filled prescription, and number of unique therapeutic classes dispensed. Outcomes were identified via linkage with participating cancer registries. All US state cancer registries were invited to participate.

Results

Overall, 153 316 patients in the teriparatide cohort and 613 247 in the comparator cohort were linked to 811 osteosarcoma cases from 26 participating state cancer registries (68% of US patients aged ≥65 years diagnosed 2007‐2014). Analysis on a subset of cohorts revealed they were balanced for known osteosarcoma risk factors and Charlson comorbidity index. Mean duration of teriparatide treatment was 10 months. No osteosarcoma cases were observed in the teriparatide cohort; the incidence rate in the comparator cohort was consistent with the background incidence rate among adults aged ≥65 years. The incidence rate ratio was 0.0 (95% confidence interval, 0.0‐3.2).

Conclusions

For US patients aged ≥65 years, incidence of osteosarcoma among those treated with teriparatide ranges from 0 to 3.2 times the incidence of osteosarcoma in those treated with other medications. Given low incidence of osteosarcoma, this range of effect is inconsistent with a large absolute increase in osteosarcoma risk.

[Overview of animal researches about the effects of systemic drugs on implant osseointegration]

Implant osseointegration is an important biological basis for dental implantology. Many factors, including surgical factors, implant factors, and patients' own factors, affect implant osseointegration. Notably, the application of systemic drugs to improve implant osseointegration has become a research hotspot. This article reviews the effects of systemic drugs on implant osseointegration based on animal researches to provide systemic drug selection to improve implant osseointegration and lay a good foundation for later clinical trials.

Higher serum uric acid is associated with higher lumbar spine bone mineral density in male health-screening examinees: a cross-sectional study

Bone health has been associated with oxidative stress and antioxidants have received interest to this end. Serum uric acid (SUA), an end product of purine metabolism in humans, has recently shown antioxidant properties regarding bone health, but there are conflicting results. The aim of this study was to investigate the relationship between SUA levels and lumbar spine bone mineral density (BMD) in clinically apparently healthy males aged 40-60 years. We performed a cross-sectional study of 6588 Korean males who completed a health-screening program from January 2011 to December 2014. Of the study participants, the mean age was 48.2 ± 10.7 years. Multiple regression analyses resulted in a significant positive association with lumbar spine BMD across SUA quintiles in a dose-response manner after adjusting for various confounding factors (p = 0.013); for each 1 mg/dl increase of SUA, BMD rose by 0.0054 g/cm² (p = 0.004). Stratified analyses revealed that this association between SUA and lumbar spine BMD was consistently observed across all clinically relevant subgroups. The present study demonstrated a positive association in males between SUA and lumbar spine BMD, suggesting that SUA could have a profitable effect on bone metabolism.

The effect of switching from teriparatide to anti-RANKL antibody on cancellous and cortical bone in ovariectomized mice

We examined the effect of teriparatide, and switching from teriparatide to anti-RANKL (receptor activator of nuclear factor κB ligand) monoclonal antibody, in ovariectomized mice. Twelve-week-old female C57BL/6 mice were ovariectomized or sham operated. Four weeks after surgery, ovariectomized mice were subjected to one of the following four treatments: phosphate-buffered saline (PBS) for 8weeks; teriparatide for 4weeks followed by PBS for 4weeks (PTH4W group); teriparatide for 8weeks (PTH8W group); or teriparatide for 4weeks followed by anti-RANKL antibody (single subcutaneous injection of 5mg/kg) (SWITCH group). Twelve weeks after the operation, bone mineral density was increased in PTH8W and SWITCH groups to broadly comparable levels, but these were significantly decreased in the PTH4W group after discontinuation of teriparatide. Histomorphometric analysis demonstrated that cancellous bone formation and resorption were profoundly suppressed in the SWITCH group. Bone formation was also suppressed on the endocortical surface of cortical bone but was maintained on the periosteal surface. Anti-RANKL antibody suppressed osteoclast activity immediately after treatment, while bone formation was only gradually decreased. These results suggest that anti-RANKL antibody may be a therapeutic option after discontinuation of teriparatide therapy.

PTH(1-34) for Surgical Hypoparathyroidism: A 2-Year Prospective, Open-Label Investigation of Efficacy and Quality of Life

CONTEXT

Daily parathyroid hormone (PTH) (1-34) administrations can reduce the required total daily dose of calcium and calcitriol and restore normocalcemia in refractory hypoparathyroidism. However, most PTH(1-34) trials have been conducted on small cohorts including subjects with hypoparathyroidism of various etiologies, and quality of life (QOL) was not investigated.

OBJECTIVE

To investigate the effects of 24-month PTH(1-34) treatment in a homogeneous cohort of adult subjects with postoperative hypoparathyroidism and to evaluate QOL changes.

DESIGN

Prospective open-label study.

SETTING

Italian multicenter study.

PARTICIPANTS

42 subjects.

INTERVENTION

Twice-daily PTH(1-34) 20 μg subcutaneous injection.

MAIN OUTCOME MEASURES

Calcium and vitamin D supplementation requirements, serum calcium, phosphate, and urinary calcium excretion (3, 6, 12, 18, 24 months). At baseline and at 6 and 24 months, QOL was evaluated by the RAND 36-Item Short Form (SF-36) Health Survey, covering eight domains of physical and mental health.

RESULTS

Mean serum calcium concentration significantly increased from baseline to 3 months (7.6 ± 0.6 vs 8.9 ± 1.1 mg/dL, P < 0.001) and remained stable until the end of the study, despite reductions in calcium and vitamin D supplementation. Phosphate levels gradually decreased from baseline to 6 months (4.3 ± 1.1 vs 3.9 ± 0.6 mg/dL, P < 0.019), remaining stable until 24 months. Serum alkaline phosphatase and calcium excretion gradually increased from baseline to 24 months. Data from SF-36 showed a significant improvement in the mean scores of all eight domains (P < 0.001).

CONCLUSION

This study demonstrates the efficacy and safety of PTH(1-34) to treat adult patients with postsurgical hypoparathyroidism. PTH(1-34) may improve their mental and physical health.

Synthesis and in vitro bone cell activity of analogues of the cyclohexapeptide dianthin G

The cyclohexapeptide natural product dianthin G promotes osteoblast (bone-forming cell) proliferation in vitro at nanomolar concentrations, and is therefore considered a promising candidate for the treatment of osteoporosis. An N(α)-methyl amide bond scan of dianthin G was performed to probe the effect of modifying amide bonds on osteoblast proliferation. In addition, to provide greater structural diversity, a series of dicarba dianthin G analogues was synthesised using ring closing metathesis. Dianthin G and one novel dicarba analogue increased the number of human osteoblasts and importantly they did not increase osteoclast (bone-resorbing cell) differentiation in bone marrow cells.

Novel heterocyclic ring-fused oleanolic acid derivatives as osteoclast inhibitors for osteoporosis

A series of novel oleanolic acid (OA) derivatives were synthesized via modifications of the A-ring and C28-amides of OA, and their anti-bone resorption activities were evaluated in vitro and in vivo.

Management of severe osteoporosis

INTRODUCTION

Severe osteoporosis represents a disease of high mortality and morbidity. Recognition of what constitutes and causes severe osteoporosis and aggressive intervention with pharmacological agents with evidence to reduce fracture risk are outlined in this review.

AREAS COVERED

This review is a blend of evidence obtained from literature searches from PubMed and The National Library of Medicine (USA), clinical experience and the author's opinions. The review covers the recognition of what constitutes severe osteoporosis, and provides up-to-date references on this sub-set of high risk patients.

EXPERT OPINION

Severe osteoporosis can be classified by using measurements of bone densitometry, identification of prevalent fractures, and, knowledge of what additional risk factors contribute to high fracture risk. Once recognized, the potential consequences of severe osteoporosis can be mitigated by appropriate selection of pharmacological therapies and modalities to reduce the risk for falling.

PTH receptor-1 signalling-mechanistic insights and therapeutic prospects

Parathyroid hormone/parathyroid hormone-related protein receptor (PTH/PTHrP type 1 receptor; commonly known as PTHR1) is a family B G-protein-coupled receptor (GPCR) that regulates skeletal development, bone turnover and mineral ion homeostasis. PTHR1 transduces stimuli from PTH and PTHrP into the interior of target cells to promote diverse biochemical responses. Evaluation of the signalling properties of structurally modified PTHR1 ligands has helped to elucidate determinants of receptor function and mechanisms of downstream cellular and physiological responses. Analysis of PTHR1 responses induced by structurally modified ligands suggests that PTHR1 can continue to signal through a G-protein-mediated pathway within endosomes. Such findings challenge the longstanding paradigm in GPCR biology that the receptor is transiently activated at the cell membrane, followed by rapid deactivation and receptor internalization. Evaluation of structurally modified PTHR1 ligands has further led to the identification of ligand analogues that differ from PTH or PTHrP in the type, strength and duration of responses induced at the receptor, cellular and organism levels. These modified ligands, and the biochemical principles revealed through their use, might facilitate an improved understanding of PTHR1 function in vivo and enable the treatment of disorders resulting from defects in PTHR1 signalling. This Review discusses current understanding of PTHR1 modes of action and how these findings might be applied in future therapeutic agents.

The safety and tolerability profile of therapies for the prevention and treatment of osteoporosis in postmenopausal women

At a time when the prevalence of osteoporosis and related fractures is increasing, initiation and continuation of pharmacologic therapies for prevention and treatment of postmenopausal osteoporosis have declined. This decline has been at least in part attributable to concerns about safety of these agents, such as atypical fractures with bisphosphonates and breast cancer with estrogen/progestin therapy, particularly when they are used long term by older women. However, in many cases, absolute risk of serious adverse effects is small and should be balanced against the larger potential for fracture reduction. Here, we review the safety and tolerability of available therapies for postmenopausal osteoporosis. Taking into consideration their relative efficacy, we also provide strategies for optimization of the risk:benefit ratio.

Coexistent osteoporosis and multiple myeloma: when to investigate further in osteoporosis

Osteoporosis commonly causes vertebral collapse fractures. We present a patient with multiple vertebral fractures in the context of severe osteoporosis, who, in the course of investigation for intractable spine and hip pain, was found to have an IgA myeloma. At 2 months post diagnosis, she was discharged home to continue outpatient chemotherapy.

PTH(1-34) for Surgical Hypoparathyroidism: A Prospective, Open-Label Investigation of Efficacy and Quality of Life

CONTEXT

Conventional therapy for hypoparathyroidism consists of calcium and calcitriol, but sometimes normal serum calcium cannot be maintained, and/or this approach might lead to nephrocalcinosis, nephrolithiasis, or renal insufficiency.

OBJECTIVE

The objective of the study was to investigate the effects of 6 months of PTH(1-34) treatment in adult subjects with postoperative hypoparathyroidism and to evaluate quality-of-life changes.

DESIGN

This was a 2-year prospective, open-label study. At baseline and after 6 months of PTH(1-34) treatment, calcium and vitamin D supplementation requirements, serum calcium, phosphate, creatinine, alkaline phosphatase, uric acid, and 24-hour urinary calcium excretion were evaluated. Quality of life was evaluated by the Rand 36-Item Short Form Health Survey covering eight domains of physical and mental health.

SETTING

This was an Italian multicentric study.

PARTICIPANTS

Participants included 42 subjects with surgical hypoparathyroidism (90% females, age range 34-77 y).

INTERVENTION

The intervention included a twice-daily PTH(1-34) 20 μg sc injection.

RESULTS

The mean serum calcium levels significantly increased from baseline to 15 days (7.6 ± 0.6 vs 9.1 ± 0.9 mg/dL, P < .001) and remained stable until the end of the observational period, despite a significant reduction in calcium and vitamin D supplementation. Phosphate levels gradually decreased from baseline to the sixth month (P = .005 for the trend), whereas the alkaline phosphatase increased (P < .001). Data from the Rand 36-Item Short Form Health Survey showed a significant improvement in the mean scores of all eight domains (P < .001).

CONCLUSION

This is the largest study that demonstrates the effectiveness of PTH(1-34) in the treatment of adult patients with postsurgical hypoparathyroidism, and it shows that PTH(1-34) may improve the mental and physical health in hypoparathyroid subjects.

Ursolic acid derivatives as bone anabolic agents targeted to tryptophan hydroxylase 1 (Tph-1)

Tryptophan hydroxylase 1 (Tph-1) initiates the biosynthesis of peripheral serotonin. As peripheral serotonin suppresses bone formation, inhibitor of Tph-1 provides a useful tool to discover anabolic agents for osteoporosis. In the present study, series of ursolic acid (UA) derivatives were synthesized, and their inhibitory activity on serotonin biosynthesis and cytotoxicity were evaluated. Among the derivatives, 8d with potent inhibitory activity on serotonin was applied for further research. The data revealed that 8d significantly inhibited protein and mRNA expressions of Tph-1, and an SPR study indicated that 8d directly interacted to Tph-1 with a binding affinity of KD=15.09μM. Oral administration of 8d significantly prevented bone loss via suppressing serotonin biosynthesis without estrogenic side-effects in ovariectomized (OVX) rats.

Management of osteoporosis in spine surgery

Osteoporosis is a burgeoning clinical problem that is characterized by decreased bone strength and density. It predisposes patients to fragility fractures and debilitating spine deformities. Several complications are associated with spine surgery in patients with osteoporosis, and there is currently no treatment algorithm to guide the spine surgeon. A multidisciplinary approach to treatment of patients with osteoporosis and spine deformity or fracture is encouraged, and preoperative planning is crucial for successful surgical outcomes. Several surgical techniques have been developed to treat osteoporosis-related deformities, including posterior instrumentation with fusion. However, achieving fixation and fusion in these patients can be difficult secondary to poor bone stock. Augmentation methods to improve pedicle screw fixation have evolved, including instrumentation at multiple levels, bioactive cement augmentation, and fenestrated or expandable pedicle screws, but their impact on clinical outcomes remains unknown. Management of osteoporosis in patients undergoing spine surgery is challenging, but with appropriate patient selection, medical optimization, and surgical techniques, these patients can experience pain relief, deformity correction, and improved function.

The safety and effectiveness profile of daily teriparatide in a prospective observational study in Japanese patients with osteoporosis at high risk for fracture: interim report

This postmarketing surveillance study assessed the safety and effectiveness of daily teriparatide treatment in patients with osteoporosis in a Japanese clinical setting. In this prospective, multicenter, observational study, patients with osteoporosis at high risk for fracture received subcutaneous injections of teriparatide (20 μg/day) for a maximum of 24 months. For this interim report, data from 1,671 patients were eligible for analysis at the cutoff date. The mean age was 75.3 years; 93% of patients (1,552/1,671 patients) were women. There were 117 adverse drug reactions (ADRs) reported in 101 of 1,671 patients (6.04%); the most common reported ADRs were nausea, dizziness, headache, and palpitations. No clinically significant safety issues were identified, although 5 serious ADRs were reported in 4/1,671 (0.24 %) patients. At 12 months, 71.9% of patients remained on teriparatide treatment. From 1 month, there were rapid increases in the biomarkers of bone formation P1NP and, to a lesser extent, BAP. In contrast, increases in the biomarkers of bone resorption, serum NTX, urinary NTX, and TRACP5b, were smaller. After 12 months of treatment, there was an increase in bone mineral density at the lumbar spine, femoral neck, and total hip, and a decrease in the Visual Analog Scale score for back pain. The incidence of new vertebral and nonvertebral fractures was 1.21% and 3.18%, respectively. In conclusion, the favorable safety profile and effectiveness of teriparatide observed in this population of Japanese patients with osteoporosis were accompanied by relatively high persistence with treatment, which is a key factor in the success of osteoporosis treatment.

Higher serum uric acid is associated with higher bone mass, lower bone turnover, and lower prevalence of vertebral fracture in healthy postmenopausal women

Higher serum uric acid (UA) was associated with higher bone mass, lower bone turnover, and lower prevalence of vertebral fracture in postmenopausal women. Furthermore, UA suppressed osteoclastogenesis and decreased production of reactive oxygen species in osteoclast precursors, indicating UA may have beneficial effects on bone metabolism as an antioxidant.

INTRODUCTION

UA is known to play a physiological role as an antioxidant, and oxidative stress has detrimental effects on bone metabolism. In the present study, we investigated the association of serum UA level with the osteoporosis-related phenotypes and its direct effect on bone-resorbing osteoclasts using in vitro systems.

METHODS

This is a large cross-sectional study, including 7,502 healthy postmenopausal women. Bone mineral density (BMD) and serum UA concentrations were obtained from all subjects. Data on bone turnover markers and lateral thoracolumbar radiographs were available for 1,023 and 6,918 subjects, respectively. An in vitro study investigated osteoclastogenesis and reactive oxygen species (ROS) levels according to UA treatment.

RESULTS

After adjusting for multiple confounders, serum UA levels were positively associated with BMD at all sites (all p < 0.001). Compared with the participants in the highest UA quartile, the odds for osteoporosis were 40 % higher in those in the lowest quartile. The serum UA levels were inversely related to both serum C-terminal telopeptide of type I collagen and osteocalcin levels (p < 0.001 and p = 0.004, respectively). Consistently, subjects with vertebral fracture had lower serum UA levels, compared with those without it (p = 0.009). An in vitro study showed that UA decreased osteoclastogenesis in a dose-dependent manner and reduced the production of ROS in osteoclast precursors.

CONCLUSION

These results provide epidemiological and experimental evidence that serum UA may have a beneficial effect on bone metabolism as an antioxidant in postmenopausal women.

Treating osteoporosis by targeting parathyroid hormone to bone

Osteoporosis is a major public health problem despite widespread use of bisphosphonate therapy. PTH(1-34) is a more effective treatment; but its use has been limited by side effects (hypercalcemia, tumor risk) and inconvenient dosing (daily injection). Long-acting forms of PTH are also effective but cause severe hypercalcemia, presumably from effects in kidney. We hypothesized that targeted delivery of PTH to bone using a collagen binding domain (PTH-CBD) could reduce hypercalcemia. PTH-CBD is cleared from serum within 12hours after subcutaneous administration. In ovariectomized rats, monthly administration of PTH-CBD increased spinal BMD by 14.2% with no associated hypercalcemia. Such bone-targeted anabolic agents may ultimately allow the superior efficacy of anabolic therapy to be obtained with the dosing convenience of bisphosphonates.

Glucocorticoid-induced osteoporosis and osteonecrosis

Glucocorticoid administration is the most common cause of secondary osteoporosis and the leading cause of nontraumatic osteonecrosis. In patients receiving long-term therapy, glucocorticoids induce fractures in 30% to 50% and osteonecrosis in 9% to 40%. This article reviews glucocorticoid-induced osteoporosis and osteonecrosis, addressing the risk factors, pathogenesis, evaluation, treatment, and uncertainties in the clinical management of these disorders.

The single dose pharmacokinetic profile of a novel oral human parathyroid hormone formulation in healthy postmenopausal women

Parathyroid hormone (PTH), currently the only marketed anabolic treatment for osteoporosis, is available as the full-length hormone, human PTH1-84, or as the human PTH1-34 fragment (teriparatide). Both must be administered as a daily subcutaneous (sc) injection. A new oral formulation of human PTH1-34 (PTH134) is being developed as a more convenient option for patients. In this single-center, partially-blinded, incomplete cross-over study, the safety, tolerability, and exposure of oral PTH134 (teriparatide combined with 2 different quantities of the absorption enhancer 5-CNAC) were assessed in 32 healthy postmenopausal women. 16 subjects were randomized to receive 4 single doses out of 6 different treatments: placebo, teriparatide 20 μg sc, or 1, 2.5, 5 or 10 mg of oral PTH134 formulated with 200 mg 5-CNAC. Subsequently, another 16 subjects were randomized to receive 4 out of 6 different treatments: placebo, teriparatide 20 μg sc, or 2.5 or 5 mg of oral PTH134 formulated with either 100 or 200 mg 5-CNAC. Doses were given ≥6 days apart. All doses of PTH134 were rapidly absorbed, and showed robust blood concentrations in a dose-dependent manner. Interestingly, PTH1-34 disappeared from blood faster after oral than after sc administration. Specifically, 2.5 and 5 mg PTH134 (containing 200 mg 5-CNAC) demonstrated Cmax and AUC0-last values closest to those of sc teriparatide 20 μg (Forsteo®). Mean+/-SD hPTH134 Cmax values were, respectively, 74+/-59, 138+/-101, 717+/-496, and 1624+/-1579 pg/mL for 1, 2.5, 5, and 10 mg doses of this peptide administered with 200 mg 5-CNAC; while mean+/-SD AUC (0-last) values were, respectively, 30+/-40, 62+/-69, 320+/-269, and 627+/-633 h*pg/mL. The corresponding estimates for teriparatide 20 μg sc were 149+/-35 for Cmax and 236+/-58 for AUC (0-last) Ionized calcium remained within normal limits in all treatment groups except for 3 isolated events. Nine subjects withdrew due to treatment-related AEs. Of those, seven were taking PTH134 2.5 or 5 mg: three withdrew for symptomatic hypotension (two of whom were in the 200 mg 5-CNAC group), three because of delayed vomiting (two from the 200 mg 5-CNAC group), one was proactively withdrawn by the investigator for symptomatic hypercalcemia (receiving 2.5 mg/100 mg 5-CNAC) at slightly supra-normal total calcium but normal ionized serum calcium levels. One subject receiving teriparatide and one receiving placebo withdrew for symptomatic hypotension. No serious AEs were reported. In conclusion, the study demonstrated potential therapeutically relevant PTH1-34 systemic exposure levels after oral administration of PTH1-34 formulated with the absorption enhancer 5-CNAC. Doses of 2.5 and 5 mg of oral PTH134 achieved exposure levels closest to those of teriparatide 20 μg sc, with a comparable incidence of AEs in healthy postmenopausal women.

ATF936, a novel oral calcilytic, increases bone mineral density in rats and transiently releases parathyroid hormone in humans

Parathyroid hormone (PTH), when injected daily as either the intact hormone PTH(1-84) or the active fragment PTH(1-34) (teriparatide), is an efficacious bone anabolic treatment option for osteoporosis patients. Injections lead to rapid and transient spikes in hormone exposure levels, a profile which is a prerequisite to effectively form bone. Oral antagonists of the calcium-sensing receptor (calcilytics) stimulate PTH secretion and represent thus an alternative approach to elevate hormone levels transiently. We report here on ATF936, a novel calcilytic, which triggered rapid, transient spikes in endogenous PTH levels when given orally in single doses of 10 and 30mg/kg to growing rats, and of 1mg/kg to dogs. Eight weeks daily oral application of 30mg/kg of ATF936 to aged female rats induced in the proximal tibia metaphysis increases in bone mineral density, cancellous bone volume and cortical and trabecular thickness as evaluated by computed tomography. In healthy humans, single oral doses of ATF936 produced peak PTH levels in plasma after a median time of 1h and levels returned to normal at 24-h post-dose. The average maximum PTH concentration increase from baseline was 1.9, 3.6, and 6.0-fold at doses of 40, 70, and 140mg. ATF936 was well tolerated. The sharp, transient increase in PTH levels produced by the oral calcilytic ATF936 was comparable to the PTH profile observed after subcutaneous administration of teriparatide. In conclusion, ATF936 might hold potential as an oral bone-forming osteoporosis therapy.

Parathyroid hormone analogues in the treatment of osteoporosis

Osteoporosis is characterized by the occurrence of fragility fractures. Over the past years, various treatment options have become available, mostly antiresorptive agents such as bisphosphonates. However, antiresorptive therapy cannot restore bone mass and structure that has been lost due to increased remodeling. In this case, recombinant human parathyroid hormone (PTH) analogues-the full-length PTH(1-84) or the shortened molecule PTH(1-34), which is also known as teriparatide-present the possibility of increasing the formation of new bone substance by virtue of their anabolic effects. The bone formation induced by PTH analogues not only increases BMD or bone mass but also improves the microarchitecture of the skeleton, thereby leading to improved strength of bone and increased mechanical resistance. Controlled trials have shown that both analogues significantly reduce the incidence of vertebral fractures, and PTH(1-34) also reduces the risk of nonvertebral fractures. The need for daily self-injection and the higher cost compared with other forms of treatment limit the widespread use of PTH analogues. Nevertheless, treatment with PTH analogues should be considered in postmenopausal women and men with severe osteoporosis, as well as in patients on established glucocorticoid treatment with a high fracture risk. Concurrent therapy with antiresorptive agents should be avoided, but sequential therapy with these agents might consolidate the beneficial effects on the skeleton.

Monthly administration of a novel PTH-collagen binding domain fusion protein is anabolic in mice

We synthesized fusion proteins of parathyroid hormone (PTH) (1-33) and the collagen binding domain of ColH (CBD) and tested them for anabolic bone activity in mice. Two fusion proteins were synthesized, linking the carboxy terminus of PTH(1-33) either directly to the amino terminal of the CBD or to the CBD through an adjacent ColH domain (PTH-PKD-CBD). Both PTH-CBD and PTH-PKD-CBD increased cAMP accumulation in cells stably transfected with the PTH/PTHrP receptor, and both peptides bound to type 1 collagen in flow-through assays. Distribution studies indicated that the PTH-CBD was concentrated in the bone and skin, tissues with abundant collagen and blood flow. Administration of 320 μg/kg PTH-CBD either weekly (for 8 weeks) or monthly (for 6 months) to 7-week-old C57BL/6J mice resulted in a sustained increase in bone mineral density (BMD) (15% for weekly studies, 13% for monthly studies; P < 0.05). PTH-PKD-CBD showed only 5% increases in BMD after weekly administration, and, as expected, neither weekly nor monthly PTH(1-34) affected BMD. PTH-CBD increased serum alkaline phosphatase levels. Importantly, there were no significant increases in serum calcium observed. Collectively, the data suggest that PTH-CBD has a sustained anabolic effect in bone with either weekly or monthly administration. This approach of targeted delivery of PTH to bone may show promise for the treatment of disorders of low bone mass, such as postmenopausal osteoporosis.

Serum uric acid is associated with bone health in older men: a cross-sectional population-based study

Serum uric acid (UA) is a strong endogenous antioxidant. Since oxidative stress has been linked to osteoporosis, we examined the association between serum UA levels and bone mineral density (BMD), prevalent vertebral and nonvertebral fractures, and laboratory measures such as calcitropic hormones and bone turnover marker levels. This cross-sectional analysis consisted of 1705 community-dwelling men aged 70 years or over who participated in the baseline part of the Concord Health and Ageing in Men Project (CHAMP), a population-based study of older men in Sydney, Australia. BMD at all sites was significantly higher among men with serum UA levels above the group median than among men with UA levels below the median. In multiple regression analyses adjusted for potential confounders, serum UA remained associated with BMD at all sites (β = 0.12 to 0.14, p < .001), serum calcium (β = 0.11, p = .001), parathyroid hormone (β = 0.09, p = .002), 25-hydroxyvitamin D (β = 0.09, p = .005), and was negatively associated with urinary excretion amino-terminal cross-linked telopeptide of type 1 collagen (β = -0.09, p = .006). Overall, serum UA accounted for 1.0% to 1.44% of the variances in BMD (R(2)  = 0.10 to 0.22). In multiple logistic regression analyses, above-median serum UA levels were associated with a lower prevalence of osteoporosis at the femoral neck [odds ratio (OR) = 0.42, 95% confidence interval (CI) 0.22-0.81, p = .010) and lumbar spine (OR = 0.44, 95% CI 0.23-0.86, p = .016) and a lower prevalence of vertebral (OR = 0.62, 95% CI 0.43-0.91, p = .015) and nonvertebral (OR = 0.51, 95% CI 0.29-0.89, p = .018) fractures. In conclusion, higher serum UA levels are associated with higher BMD at all skeletal sites and with a lower prevalence of vertebral and nonvertebral fractures in older men.

Role of teriparatide in treatment of glucocorticoid-induced osteoporosis

Glucocorticoids are commonly used in various fields within medicine. One of their most common and clinically significant side effects is glucocorticoid-induced osteoporosis (GIOP). GIOP is a disease leading to progressive decreases in bone mineral density, decreased bone strength, and increased risk of skeletal fractures. GIOP has a significant impact on the morbidity and health-related quality of life of the patients it affects. Glucocorticoids have deleterious effects on bone through promoting osteoblast apoptosis and inhibiting osteoblastogenesis. Teriparatide exerts anabolic effects on bone, so it is understandable why teriparatide is thought to be a rational treatment option. Clinical studies have indicated teriparatide is efficacious in the treatment of GIOP to improve bone mineral density values at the lumbar spine and femoral neck. Some evidence also suggests teriparatide may reduce rates of vertebral fractures in GIOP patients. Overall, this review of the current clinical evidence suggests teriparatide may be an efficacious and promising agent in the treatment of GIOP.

Anabolic and antiresorptive drugs improve trabecular microarchitecture and reduce fracture risk following radiation therapy

Many patients with symptomatic bone metastases receive radiation therapy, even though radiation is known to have potential adverse effects on bone. We hypothesized that the concurrent use of a bisphosphonate drug (zoledronic acid, ZA) or a combination of ZA plus an anabolic agent (parathyroid hormone, PTH) would lead to improvements in the microarchitecture and mechanical properties of irradiated bone. Human breast cancer cells were injected into the distal femur of 56 female nude mice, which were then divided into four groups: no treatment (0 Gy), radiation administered 4 weeks postinjection (20 Gy), radiation plus ZA (12.5 microg/kg weekly from weeks 4 to 12) (20 Gy + ZA), and radiation followed by ZA (25 microg/kg weekly from weeks 4 to 8) and PTH(1-34) (100 microg microg/kg daily from weeks 8 to 12) (20 Gy + ZA + PTH). Left limbs served as normal control bones. Bone loss over the 12-week study was tracked with serial radiography and bone densitometry. At the end of the study, micro-computed tomography and mechanical testing were used to quantify bone microarchitecture and bone strength. Radiation alone failed to prevent tumor-induced decreases in bone mineral density (BMD), trabecular bone volume, and bone strength. Treatment with 20 Gy + ZA or 20 Gy + ZA + PTH as adjuncts to radiation was effective at preserving trabecular bone architecture and bone strength at normal levels. ZA reduced the risk of mechanical fragility following irradiation of a lytic bone lesion. Supplemental use of PTH did not result in further increases in bone strength but was associated with significant increases in BMD and bone mass, suggesting that it may be beneficial in enhancing bone architecture following radiation therapy.

Update on the efficacy, safety, and adherence to treatment of full length parathyroid hormone, PTH (1-84), in the treatment of postmenopausal osteoporosis

Full length (1-84) parathyroid hormone (PTH) was introduced in Europe as a treatment for postmenopausal osteoporosis in 2006. The efficacy of PTH (1-84) in the prevention of vertebral fractures is very high, and is similar to that of teriparatide. Its action in the prevention of femoral fractures has yet to be fully demonstrated, but the incidence of such fractures in trials was very low, and a decrease in nonvertebral fractures was seen in high-risk patients. The effect on bone mineral density (BMD) was clearly demonstrated in the spine and also in the hip. The effects on BMD were evident and increased progressively with treatment until 36 months. After its discontinuation there was a clear decrease in BMD if no antiresorptive treatment was initiated. Increases in bone volumetric density and bone volume in trabecular sites were also reported. Moreover, a bone volume increase was detected in cortical sites. Hypercalcemia and hypercalciuria are frequent consequences of PTH treatment, but rarely have clinical effects and are usually well controlled by reducing calcium and vitamin D supplementation.

Review of osteoporosis pharmacotherapy for geriatric patients

BACKGROUND

Fractures are a significant problem in geriatric patients, and understanding the evidence for benefit and possible harm of osteoporosis treatments is critical to appropriate management of this patient population.

OBJECTIVE

The purpose of this article was to review the evidence and treatment considerations related to use of the approved osteoporosis treatments in the United States across the continuum of ages in the geriatric population.

METHODS

MEDLINE and the Web of Science were searched to find English-language articles published from 2000 through July 2009. Search terms included: practice guideline, osteoporosis, calcium, vitamin D, pharmacoeconomics, ethnicity, and treatment. The generic names of each of the osteoporosis treatments approved in the United States were searched to find relevant clinical trials and randomized controlled trials (RCTs). Pivotal trials that included fracture data or focused specifically on elderly patients (> or = 60 years of age) were selected. Bibliographies in the identified articles were searched for additional articles, and the prescribing information for each of the approved treatments was reviewed.

RESULTS

Many osteoporosis studies have a mean patient age >60 years, but data for older patients are limited. Subanalyses of older patient groups have found risedronate to be beneficial for vertebral fractures in patients aged 70 to 79 years (absolute risk reduction [ARR], 8.4%; P < 0.001) and teriparatide to be beneficial for both vertebral (ARR, 6.4%; P < 0.05) and new nonvertebral fragility fractures (ARR, 9.9%; P < 0.05) in women aged > or = 75 years. However, no RCTs of geriatric patients who were either nonambulatory or had multiple comorbidities were identified in the literature.

CONCLUSIONS

Evidence indicates that the osteoporosis treatments currently available in the United States are beneficial for treating osteoporosis in geriatric patients. However, data are limited for the oldest patients (> or = 80 years) and those with significant comorbidities. Because of the limited availability of data for geriatric patients with significant comorbidities, the properties of the various agents, including efficacy, tolerability, and potential contraindications, should be considered carefully for each geriatric patient.

The use of PTH in the treatment of osteoporosis

Anabolic drugs have recently widened therapeutic options in osteoporosis treatment, as they influence processes associated with bone formation to a greater extent and earlier than bone reabsortion. They positively affect a number of skeletal properties besides bone density, as intermittent administration of parathyroid hormone (PTH) results in an increase in the number and activity of osteoblasts leading to an increase in bone mass and improvement in skeletal architecture at both the trabecular and cortical bone. Human recombinant parathyroid hormone (hrPTH 1-84) and human recombinant PTH peptide 1-34 (teriparatide) belong to this group. The objective of this paper is to review PTH actions, benefits and adverse effects, action on biochemical markers, combination therapy with antiresorptive agents, impact of antiresorptive therapy prior to anabolic treatment, sequential treatment, and effect on glucocorticoid-induced osteoporosis.

New and emerging treatments for osteoporosis

A variety of new treatments for osteoporosis have become available within the last several years, and a number of emerging treatments remain in late clinical stage development. New and emerging treatments include more potent members, or more convenient formulations, of existing classes of therapy, but a number of the emerging treatments are first-generation compounds addressing specific therapeutic targets based on recent advances in understanding of basic bone biology. These new and emerging treatments include agents with anticatabolic effects, compounds with anabolic effects, and one agent possibly containing both anticatabolic and anabolic effects. The increasing variety of new and emerging treatments increases the possibility that effective therapy will be targeted to the specific needs of the individual patient.

A bicistronic expression strategy for large scale expression and purification of full-length recombinant human parathyroid hormone for osteoporosis therapy

Parathyroid hormone (PTH) contributes to the increase of trabecular connectivity and is a candidate medication for effective treating osteoporosis. PTH is a protein of 84 amino acids and some studies have suggested that the active site lies within the range from amino acid (aa) 1 to 34. However, a few reports have indicated a causal relationship between PTH (aa 1-34) and osteogenic sarcoma in rats, while some less obvious but important roles of the carboxyl-terminus of PTH were also found. Unfortunately, it is difficult to obtain the active integrated PTH (1-84) in vitro, due to the instability of both the protein and its mRNA. Because an alternative translation start site is located at +25 nucleotides downstream of the true start site, a truncated PTH can be translated. We constructed a rhPTH bicistronic expression plasmid (pTrepth) that could highly express non-fusion soluble rhPTH proteins in Escherichia coli. The BL-21(DE3) containing pTrepth was cultured on a small scale until satisfactory expression and purification results were obtained. We then amplified the transformed cells in a 15-L fermentor and harvested 27g/L cells (wet weight). Extensive rhPTH purification was achieved by a three step chromatography process. Activity tests demonstrated that our purified protein could dramatically increase cAMP in osteosarcoma cells in vitro.

Effects of teriparatide treatment and discontinuation in postmenopausal women and eugonadal men with osteoporosis

CONTEXT

In postmenopausal women, bone mineral density (BMD) declines after teriparatide therapy is stopped. The pattern of BMD loss after teriparatide therapy is stopped in men is less clear.

OBJECTIVE

The aim of the study was to determine whether the pattern of teriparatide-induced bone accrual and post-teriparatide bone loss differs between postmenopausal women and eugonadal men.

DESIGN

We conducted a prospective cohort substudy.

PATIENTS

The study included 14 postmenopausal women and 17 eugonadal men, ages 46-85 yr, with lumbar spine or femoral neck BMD T-scores below -2.

INTERVENTION

Teriparatide (37 microg sc daily) was administered for 24 months, followed by 12 months off therapy.

MAIN OUTCOME MEASURES

We measured BMD at various anatomic sites by dual-energy x-ray absorptiometry, trabecular spine BMD by quantitative computed tomography, and bone turnover markers during the treatment and observation periods. The response to teriparatide administration and discontinuation was compared between females and males.

RESULTS

BMD of the spine, femoral neck, total hip, and trabecular spine increased similarly during the treatment period in men and women, whereas BMD at the radius was stable in men but decreased by 8.1 +/- 3.3% in women (P < 0.0001). After teriparatide was stopped, BMD at the posterior-anterior spine decreased by 7.1 +/- 3.8% in women and by 4.1 +/- 3.5% in men (P = 0.036). BMD at the total hip and femoral neck decreased by 3.8 +/- 3.9 and 3.1 +/- 4.3%, respectively, in women but remained stable in men (P < 0.05 for both sites). BMD at the distal radius remained stable in men but increased in women by 1.6 +/- 3.1% (P = 0.069).

CONCLUSIONS

Teriparatide appears to increase BMD similarly in postmenopausal women and eugonadal men with osteoporosis. After teriparatide is stopped, the decline in BMD is greater in women than in men. If confirmed in larger cohorts, these findings would suggest that the indication for immediate antiresorptive therapy after teriparatide may not be as urgent in men as in women.