Parathyroid hormone for the treatment of osteoporosis: a systematic review

Unraveling the relationship between serum parathyroid hormone levels and trabecular bone score: a cross-sectional study

The TBS is a new method for clinicians to assess the bone quality. It is directly related to the mechanical strength of bone and helps predict fracture risk. The present analysis aimed to investigate the associations between serum PTH levels and TBS by analyzing data from the National Health and Nutrition Examination Survey (NHANES). A total of 3516 participants from the NHANES 2005-2006 were included in this cross-sectional study. The independent variable was serum PTH, and the outcome variable was TBS. The associations of serum PTH levels with TBS were examined using multivariable linear regression models. After adjusting for covariates, there was a negative association between serum PTH level and TBS (β = - 0.0034; 95% confidence interval, - 0.0050 to - 0.0017). However, in the subgroup analysis stratified by gender, race, and age, this association became negative only in Non-Hispanic White (β =  - 0.0047, 95% CI:  -  0.0071 to  -  0.0048) and young people (age < 60) (β = - 0.0036, 95% CI: - 0.0057, - 0.0016), regardless of gender. In addition, the association of serum PTH with TBS was an U-shaped curve, with a point of inflection at 6.71 pmol/L. This study showed that serum PTH level was negatively associated with TBS. Maintaining PTH levels in a lower reasonable clinical range may be beneficial to bone health, especially for young non-Hispanic white.

Parathyroid hormone promotes induction of beige adipocytes and reversibly ameliorates muscle quality and atrophy following chronic rotator cuff tear in a rat model

BACKGROUND

Fatty infiltration (FI) and muscle atrophy (MA) in the rotator cuff muscles following rotator cuff tears (RCT) persist postrepair, increasing the risk of re-tears. Brown adipocyte-like "beige adipocytes" are expected to have a therapeutic effect on intramuscular FI and MA due to their lipolytic activity and the muscle regenerative effects of their secreted factors. However, whether parathyroid hormone (PTH) ameliorates the already advanced FI and MA remains unknown. Therefore, this study aimed to clarify whether PTH promotes the expression of beige adipocytes and ameliorates advanced FI and MA following chronic RCT in rats.

METHODS

Supraspinatus muscles were harvested from rats with chronic RCT after 4 or 8 weeks of PTH treatment and compared to those in the control group or to those at the start of treatment. FI was assessed by Oil Red O staining, and the staining area was evaluated as a percentage of the muscle cross-sectional area. MA was evaluated by measuring muscle wet weight and cross-sectional area of muscle fiber. Beige adipocyte expression was evaluated by immunostaining for uncoupling protein 1 (UCP1). Fibro-adipogenic progenitors (FAPs) were separated from muscle-injured mice. We assessed whether PTH could diminish fat droplet accumulation by promoting the differentiation of FAPs into beige adipocytes.

RESULTS

After 4 weeks, PTH reduced the area fraction of FI in the rat supraspinatus muscle following chronic RCT compared with that at the beginning of treatment (P = .028). In addition, PTH increased wet muscle mass (P < .001), and muscle fiber cross-sectional area (P = .018) compared with measurements at the start of treatment. PTH administration promoted the expression of UCP1, a beige adipocyte marker, in the supraspinatus muscle (P = .019). PTH increased gene expression of beige adipocyte-related markers and suppressed fat droplet accumulation even after adipogenic differentiation of FAPs (P = .004) but did not reduce fat droplets that had already accumulated in in vitro experiments.

CONCLUSIONS

PTH facilitated beige adipocyte expression and reversibly ameliorated muscle quality and atrophy following chronic RCT by hindering fat droplet accumulation and facilitating muscle regeneration. Therefore, PTH may be a medical treatment for FI and MA following RCT, leading to expanded rotator cuff repair indications.

Diagnosis and Management of Osteoporosis: A Comprehensive Review of Guidelines

Importance

Osteoporosis causes increased morbidity and mortality, and thus poses a significant economic burden to the health systems worldwide.

Objective

The aim of this study was to review and compare the most recently published major guidelines on diagnosis and management of this common medical entity.

Evidence Acquisition

A thorough comparative review of the most influential guidelines from the RACGP (Royal Australian College of General Practitioners), the ESCEO-IOF (European Society for Clinical and Economic Aspects of Osteoporosis-International Osteoporosis Foundation), the NOGG (National Osteoporosis Guideline Group), the NAMS (North American Menopause Society), the ES (Endocrine Society), and the ACOG (American College of Obstetricians and Gynecologists) was conducted.

Results

The reviewed guidelines generally agree on the definition, the criteria, and investigations used to diagnose osteoporosis. They also concur regarding the risk factors for osteoporosis and the suggested lifestyle modifications (calcium and vitamin D intake, normal body weight, reduction of alcohol consumption, and smoking cessation). However, there is lack of consensus on indications for fracture risk assessment in the general population and the exact indications for bone mineral density assessment. Referral to a bone specialist is reserved for complex cases of osteoporosis (NOGG, NAMS, and ACOG) or in case of inadequate access to care (RACGP). The use of hip protectors to reduce the risk of fractures is supported by RACGP, NOGG, and NAMS, solely for high-risk elderly patients in residential care settings. All guidelines reviewed recognize the efficacy of the pharmacologic agents (ie, bisphosphonates, denosumab, hormone therapy, and parathyroid hormone analogs). Nonetheless, recommendations regarding monitoring of pharmacotherapy differ, primarily in the case of bisphosphonates. The proposed intervals of repeat bone mineral density testing after initiation of drug therapy are set at 2 years (RACGP), 1-3 years (NAMS, ES, and ACOG), or 3-5 years (ESCEO-IOF and NOGG). All guidelines agree upon the restricted use of bone turnover markers only in bone specialist centers for treatment monitoring purposes. Finally, the definition of treatment failure varies among the reviewed guidelines.

Conclusions

Osteoporosis is a distressing condition for women, mainly those of postmenopausal age. Thus, it seems of paramount importance to develop consistent international practice protocols for more cost-effective diagnostic and management techniques, in order to improve women's quality of life.

Parathyroid Hormone Inhibits Fatty Infiltration and Muscle Atrophy After Rotator Cuff Tear by Browning of Fibroadipogenic Progenitors in a Rodent Model

BACKGROUND

Progressive fatty infiltration and muscle atrophy after rotator cuff tears lead to tendon repair failure and poor outcomes. Fibro-adipogenic progenitors (FAPs) are involved in fatty infiltration and muscle homeostasis of skeletal muscle. Inducing FAP differentiation into brown adipocyte-like "beige adipocytes" suppresses fatty infiltration and muscle atrophy.

HYPOTHESIS

Parathyroid hormone (PTH) suppresses fatty infiltration and muscle atrophy after rotator cuff tears in a rat model by browning of FAPs.

STUDY DESIGN

Controlled laboratory study.

METHODS

PTH was administered subcutaneously for 4 or 8 weeks to a rotator cuff tear model in rats. After treatment, fatty infiltration of supraspinatus muscles was assessed using Oil Red O staining and muscle atrophy using wet muscle weight and muscle fiber cross-sectional area. Costaining of platelet-derived growth factor receptor α (FAP marker) and uncoupling protein 1 (browning marker) was performed to confirm FAP browning by PTH. Mouse-isolated FAPs were cultured with PTH and evaluated for browning-related gene expression and adipogenic differentiation using BODIPY staining. Myogenic differentiation of C2C12 myoblasts was evaluated using coculture of PTH-treated browning FAPs with C2C12.

RESULTS

PTH inhibited fatty infiltration after rotator cuff tear at 8 weeks. Rotator cuff wet muscle loss of PTH-treated rats was inhibited at 4 and 8 weeks. Furthermore, PTH-treated rats demonstrated larger myofiber cross-sectional area than did untreated rats at 4 and 8 weeks. Costaining indicated colocalization of platelet-derived growth factor receptor α and uncoupling protein 1 and promoted PTH-induced FAP browning. PTH increased the expression of browning-related genes in FAPs and suppressed fat droplet accumulation in vitro. Coculture with PTH-treated FAPs promoted C2C12 cell differentiation into myotubes.

CONCLUSION

PTH induced FAP-derived beige adipocytes by upregulating browning-related gene expression, and the browning effect of PTH on FAPs inhibited fatty infiltration and muscle atrophy in the rat rotator cuff tear model. PTH might have potential as a therapeutic drug for fatty infiltration and muscle atrophy after rotator cuff tears.

CLINICAL RELEVANCE

PTH may expand treatment options for rotator cuff tears by reducing fatty infiltration and muscle atrophy after rotator cuff tears by browning of FAPs.

Roles of the Siglec family in bone and bone homeostasis

Tremendous progress has been seen in the study of the role of sialic acid binding im-munoglobulin type lectins (Siglecs) in osteoimmunology in the past two decades. Interest in Siglecs as immune checkpoints has grown from the recognition that Siglecs have relevance to human disease. Siglecs play important roles in inflammation and cancer, and play key roles in immune cell signaling. By recognizing common sialic acid containing glycans on glycoproteins and glycolipids as regulatory receptors for immune cell signals, Siglecs are expressed on most immune cells and play important roles in normal homeostasis and self-tolerance. In this review, we describe the role that the siglec family plays in bone and bone homeostasis, including the regulation of osteoclast differentiation as well as recent advances in inflammation, cancer and osteoporosis. Particular emphasis is placed on the relevant functions of Siglecs in self-tolerance and as pattern recognition receptors in immune responses, thereby potentially providing emerging strategies for the treatment of bone related diseases.

Understanding the mechanistic potential of plant based phytochemicals in management of postmenopausal osteoporosis

Postmenopausal osteoporosis, an epidemic disorder is defined as a loss in bone mineral density and a greater possibility of fractures in older women. It is a multifactorial disease under the control of various genetic, hormonal, and environmental factors. Insufficiency of estrogen hormone, leads to postmenopausal osteoporosis. Hormone replacement therapy (HRT), despite being the most effective treatment, it is associated with the risk of breast cancer and cardiovascular disorders. This review seeks to compile the most recent information on medicinal plants and natural compounds used to treat and prevent postmenopausal osteoporosis. Furthermore, the origin, chemical constituents and the molecular mechanisms responsible for this therapeutic and preventive effect are also discussed. Literature research was conducted using PubMed, Science direct, Scopus, Web of Science, and Google Scholar. Different plant extracts and pure compounds exerts their antiosteoporotic activity by inhibition of RANKL and upregulation of OPG. RANKL signaling regulates osteoclast formation, characterized by increased bone turnover and osteoprotegrin is a decoy receptor for RANKL thereby preventing bone loss from excessive resorption. In addition, this review also includes the chemical structure of bioactive compounds acting on NFκB, TNF α, RUNX2. In conclusion, we propose that postmenopausal osteoporosis could be prevented or treated with herbal products.

Topical application of the plant extract SDTL-E in ovariectomized rats: A potential new approach for treating osteoporosis

Current osteoporosis medications have drawbacks of causing side effects and having slow onset, therefore developing osteoporosis drugs with faster onset and less side effects is essential. This study investigated the effects of the natural plant extract, SDTL-E, in ovariectomized (OVX)-induced osteoporosis rats. Rats were randomly assigned to sham operation control group (Control Group); OVX rat model group (Model Group) or OVX rat SDTL-E treatment group (SDTL-E Group). All groups underwent ovariectomy, but the Control Group did not have the ovaries removed. SDTL-E Group was treated with SDTL-E, Model and Control Groups were treated with vegetable oil, treatments were topically applied twice daily for 20 days. Results showed when compared with Model Group, SDTL-E Group significantly restored serum estradiol back to near Control Group level, serum ALP activity, serum and urinary calcium were significantly decreased, bone mechanics indicators increased and trabecular bone numbers slightly increased. These results demonstrated 20 days of SDTL-E topical treatment improved bone strength and trabecular bone structure in OVX-induced osteoporosis rats. The underlying mechanisms include restoring estradiol level, reducing bone turnover, net bone resorption, bone calcium loss, and calcium excretion through kidney. These findings suggest topical application of plant extract is a potential new approach with quick efficacy for treating osteoporosis.

Specificity of clinical trials of some osteoporosis medicines

Clinical trials of medicinal products related to the prevention and treatment of osteoporosis cover all activities, operations, methods and means for obtaining summary data and their interpretation in order to reveal the nature of the procedures, as well as certain relationships and dependencies of interest imposed the relevant study. The main objectives of the analysis are to characterize the relationships and dependencies, to measure the significance of these relationships, to model statistically significant relationships and dependencies. An important condition for conducting the statistical analysis is that the data are comparable, i.e. to be based on unambiguously defined features and criteria for their internal content.

Objective: This work covers a documentary analysis of conducted clinical trials of drugs for the treatment of osteoporosis, as well as an analysis of the conducted clinical trials of the drug.

Denosumab.

Methods: Gathering primary empirical information, allowing for: objectification of certain facts; for retrospective study of events and phenomena in a long period; allows to determine the direction of development of the process of clinical trials and processes. The applied statistical analysis covers activities, operations, methods and means for obtaining summary data and for their interpretation in order to reveal the nature of the procedures, as well as certain connections and dependencies.

Results: Studies show that clinical trials of osteoporosis products have the following limitations: gender differentiation – although the disease occurs in both sexes, studies in female patients are more common, patients are required to are in menopause, in some studies it is required as including criteria – the presence of a fracture due to osteoporosis, the age characteristic of patients is on average 45–80 years. All analyzed drugs show a positive effect on the state of bone density and bone structure.

Conclusion: All analyzed medicinal products show a positive effect on the state of bone density and bone structure but the process is irreversible, so early prevention associated with early diagnosis would lead to earlier treatment measures in the early stages of the disease, which in turn, it would lead to long-term savings in indirect and difficult-to-estimate costs for society as a whole.

An antibody against Siglec-15 promotes bone formation and fracture healing by increasing TRAP+ mononuclear cells and PDGF-BB secretion

Osteoporosis (OP) is a common age-related disease characterized by a deterioration of bone mass and structure that predisposes patients to fragility fractures. Pharmaceutical therapies that promote anabolic bone formation in OP patients and OP-induced fracture are needed. We investigated whether a neutralizing antibody against Siglec-15 can simultaneously inhibit bone resorption and stimulate bone formation. We found that the multinucleation of osteoclasts was inhibited in SIGLEC-15 conditional knockout mice and mice undergoing Siglec-15 neutralizing antibody treatment. The secretion of platelet-derived growth factor-BB (PDGF-BB), the number of tartrate-resistant acid phosphatase-positive (TRAP⁺) mononuclear cells, and bone formation were significantly increased in the SIGLEC-15 conditional knockout mice and antibody-treated mice. The anabolic effect of the Siglec-15 neutralizing antibody on bone formation was blunted in mice with Pdgfb deleted in TRAP⁺ cells. These findings showed that the anabolic effect of the Siglec-15 neutralizing antibody was mediated by elevating PDGF-BB production of TRAP⁺ mononuclear cells. To test the therapeutic potential of the Siglec-15 neutralizing antibody, we injected the antibody in an ovariectomy-induced osteoporotic mouse model, which mimics postmenopausal osteoporosis in women, and in two fracture healing models because fracture is the most serious health consequence of osteoporosis. The Siglec-15 neutralizing antibody effectively reduced bone resorption and stimulated bone formation in estrogen deficiency-induced osteoporosis. Of note, the Siglec-15 neutralizing antibody promoted intramembranous and endochondral ossification at the damaged area of cortical bone in fracture healing mouse models. Thus, the Siglec-15 neutralizing antibody shows significant translational potential as a novel therapy for OP and bone fracture.

Present and future scope of recombinant parathyroid hormone therapy in orthopaedics

Parathyroid Hormone (PTH) has a significant role in calcium metabolism. Its intermittent administration has an anabolic effect on bone mineralization. Teriparatide (PTH 1-34), a recombinant form of parathyroid hormone, is useful in the treatment of osteoporosis, fracture healing, non-union, stress fracture, augmentation of implant fixation with bone, and chondroprotection in osteoarthritis. The present review article will elaborate on the potential approved uses of recombinant PTH in orthopedics and its evolving role in the management of fracture osteosynthesis and other common challenging bone pathologies.

Scope and Limits of Teriparatide Use in Delayed and Nonunions: A Case Series

Nonunion is known to occur in up to 10% of all bone fractures. Until recently, the treatment options considered in cases of delayed union and nonunion focused on revision surgery and improvement of local healing. Lately, teriparatide has been introduced as an osteoanabolic factor that induces fracture healing in cases with delayed or nonunions. We report on a series of five cases of delayed and nonunions treated with teriparatide: delayed unions of an atypical femoral fracture, of a multifragmentary clavicle fracture, and of a periprosthetic humeral fracture; nonunion of a tibial and fibular fracture; and infected nonunion of a tibial and fibular fracture. Based on this series, the indications and limits of application of teriparatide in cases of impaired fracture healing are discussed. Due to the “off-label” character of this application, informed consent, and cost coverage from the healthcare insurance must be obtained prior to treatment. In our experience and according to the limited existing literature, teriparatide is a safe feasible treatment in cases of delayed and nonunions with a reasonable need of resources. While adequate biomechanical stability remains the cornerstone of fracture healing, as well as healing of nonunions, teriparatide could help avoid repetitive surgeries, especially in atrophic delayed and nonunions, as well as in patients with impaired fracture healing undergoing bisphosphonate therapy. There is an urgent need for widely accepted definitions, standardized protocols, as well as further clinical trials in the field of impaired fracture healing.

Clinical Application of Teriparatide in Fracture Prevention: A Systematic Review

BACKGROUND

Teriparatide, a 1-34 fragment of parathyroid hormone (PTH) that maintains most of the biological activities of PTH, has been employed since 2002 as an anabolic agent for osteoporotic individuals who are at high risk of fracture. The purpose of the present review is to provide a systematic summary and timely update on treatment with teriparatide for fracture prevention.

METHODS

Electronic databases, including OVID MEDLINE, OVID Embase, and the Cochrane Library, were searched on February 9, 2018, to identify published systematic reviews and meta-analyses addressing treatment with teriparatide for fracture prevention, and A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) was used to assess the quality of included studies.

RESULTS

Seventeen studies were included. Of the 17 eligible studies, 3 were rated as high quality, 3 were rated as moderate quality, 6 were rated as low quality, and 5 were rated as critically low quality. Teriparatide reduced vertebral and overall nonvertebral fractures in osteoporotic patients regardless of the existence of precipitating conditions, including postmenopausal status, glucocorticoid treatment, and chronic kidney disease, as compared with placebo, but not the site-specific nonvertebral fractures of the wrist and hip. Teriparatide did not more effectively reduce fracture risks when compared with other medications, such as bisphosphonates, selective estrogen receptor modulators, RANKL (receptor activator of nuclear factor kappa-beta ligand) inhibitor, or strontium ranelate.

CONCLUSIONS

Teriparatide was safe and was not associated with an increased rate of adverse events when compared with other drugs. Teriparatide was effective for the prevention of vertebral and overall nonvertebral fractures in osteoporotic patients but not for the prevention of site-specific nonvertebral fractures at the wrist and hip.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Identification of Patients with Osteoporotic Vertebral Fractures via Simple Text Search of Routine Radiology Reports

Secondary fracture prevention programs mostly identify patients with symptomatic non-vertebral fractures, whereas asymptomatic vertebral fractures are usually missed. We here describe the development and validation of a simple method to systematically identify patients with radiographic vertebral fractures using simple text-based searching of free-text radiology reports. The study consisted of two phases. In the development phase (DP), twelve search terms were used to identify vertebral fractures in all X-ray and CT reports issued over a period of 6 months. Positive reports were manually reviewed to confirm whether or not a vertebral fracture had in fact been reported. The three search terms most effective in detecting vertebral fractures during the DP were then applied during the implementation phase (IP) over several weeks to test their ability to identify patients with vertebral fractures. The search terms 'Loss of Height' (LoH), 'Compression Fracture' (CoF) and 'Crush Fracture' (CrF) identified the highest number of imaging reports with a confirmed vertebral fracture. These three search terms identified 581 of 689 (84%) of all true vertebral fractures with a positive predictive value of 76%. Using these three terms in the IP, 126 reports were identified of which 100 (79%) had a vertebral fracture confirmed on manual review. Amongst a sample of 587 reports in week 1 of the IP, 7 (1.2%) were false negatives. Many patients with vertebral fractures can be identified via a simple text-based search of electronic radiology reports. This method may be utilised by secondary fracture prevention programs to narrow the 'care gap' in osteoporosis management.

G protein-coupled receptors as anabolic drug targets in osteoporosis

Osteoporosis is a progressive bone disorder characterised by imbalance between bone building (anabolism) and resorption (catabolism). Most therapeutics target inhibition of osteoclast-mediated bone resorption, but more recent attention in early drug discovery has focussed on anabolic targets in osteoblasts or their precursors. Two marketed agents that display anabolic properties, strontium ranelate and teriparatide, mediate their actions via the G protein-coupled calcium-sensing and parathyroid hormone-1 receptors, respectively. This review explores their activity, the potential for improved therapeutics targeting these receptors and other putative anabolic GPCR targets, including Smoothened, Wnt/Frizzled, relaxin family peptide, adenosine, cannabinoid, prostaglandin and sphingosine-1-phosphate receptors.

The effects of parathyroid hormone peptides on the peripheral skeleton of postmenopausal women. A systematic review

Given current developments in anabolic therapy for bone, we wished to document the effects of the only currently available anabolic therapy, parathyroid hormone (PTH) peptides, on the peripheral skeleton of postmenopausal women. We undertook a systematic review of English articles using MEDLINE, Scopus and the Cochrane Controlled Trials Register (final update 28th March 2016). Additional studies were identified through searches of bibliographies. Studies included those comparing PTH peptides with placebo, with anti-osteoporotic treatments and in combination therapies. Participants had to be postmenopausal women and outcomes included areal or volumetric bone mineral density (BMD) and measurements of bone microarchitecture at peripheral sites, such as the forearm and tibia. Data were extracted independently and reviewed by EVM and LMM. Data on study design were also collected for methodological risk of bias assessment. The heterogeneity between studies, regarding the drug dose and duration, and the site measured, prevented grouped meta-analysis. There were no significant differences in areal BMD between PTH peptides and placebo at peripheral skeletal sites at 12months. A decrease in aBMD occurred with PTH(1-34) (larger dose) and PTH(1-84) treatment at 18months follow-up in comparison to the placebo arms. Anti-resorptives seemed to attenuate losses of aBMD at peripheral sites when compared to PTH peptides monotherapy, likely mediated by lower cortical porosity. Finally, PTH peptides combined with bisphosphonates or denosumab attenuated peripheral BMD losses in comparison to PTH peptide monotherapy, with evidence of increased BMD at ultradistal peripheral sites when PTH(1-34) was combined with denosumab or hormone replacement therapy. This summary should act as a reference point for the comparison of new anabolic therapies, specifically in comparison to PTH(1-34).

Melatonin dietary supplement as an anti-aging therapy for age-related bone loss

INTRODUCTION

Previous studies have shown that melatonin, an anti-oxidant molecule secreted from the pineal gland, is a positive regulator of bone mass. However, the potential effects of melatonin on bone mass have never been investigated in an old population. The aim of this study was to assess the effects of dietary melatonin supplementation on mass accrual and biomechanical properties of old rat femora.

METHODS

Twenty 22-month-old male Wistar rats were divided into two randomly assigned groups. The first group was treated for 10 weeks with melatonin, whereas the second group was untreated (control). Rat femurs were collected, and their phenotypes and biomechanical properties were investigated by micro-computed tomography, histomorphometry, and a three-point-bending test. Statistical analyses were performed by the Student two-tailed unpaired t-test. In all experiments, a value of p<0.05 was considered significant.

RESULTS

Rats treated with melatonin had higher bone volume, bone trabecular number, trabecular thickness, and cortical thickness in comparison to the control group. Histomorphometric analyses confirmed the increase of bone volume in melatonin-treated rats. In agreement with these findings, melatonin-treated rats showed higher bone stiffness, flexural modulus, and ultimate load compared to controls.

CONCLUSION

These compelling results are the first evidence indicating that dietary melatonin supplementation is able to exert beneficial effects against age-related bone loss in old rats, improving the microstructure and biomechanical properties of aged bones.

The Effect of Thyroid Hormone, Prostaglandin E2, and Calcium Gluconate on Orthodontic Tooth Movement and Root Resorption in Rats

STATEMENT OF THE PROBLEM

A major objective of investigators is to clarify the role of metabolites in achievement of maximum tooth movement with minimal root damage during orthodontic tooth movement (OTM).

PURPOSE

The aim of this study was to determine the effect of administration of thyroid hormone, prostaglandin E2, and calcium on orthodontic tooth movement and root resorption in rats.

MATERIALS AND METHOD

Sixty four male Wistar rats were randomly divided into 8 groups of eight rats each: 1- 20µg/kg thyroxine was injected in traperitoneally after installation of the orthodontic appliance.  2- 0.1 ml of 1 mg/ml prostaglandin E2 was injected submucosally.  3- 10% (200 mg/kg) calcium gluconate was injected.  4- Prostaglandin E2 was injected submucosally and 10% calcium was injected intraperitoneally.  5- Thyroxine was injected intraperitoneally and prostaglandin E2 was injected submucosally.  6- 20µg/kg thyroxine with calcium was injected. 7- Prostaglandin E2 was injected submucosally with calcium and thyroxine.  8- Distilled water was used in control group. The orthodontic appliances comprised of a NiTi closed coil were posteriorly connected to the right first molar and anteriorly to the upper right incisor. OTM was measured with a feeler gauge. The mid-mesial root of the first molar and the adjacent tissues were histologically evaluated. The Data were analyzed by one-way ANOVA and Student-Newman-Keuls test.

RESULTS

The highest mean OTM was observed in the thyroxine and prostaglandin E2 group (Mean±SD = 0.7375±0.1359 mm) that was significantly different (p< 0.05). A significant difference (p< 0.05) in root resorption was observed between the prostaglandin E2 (0.0192±0.0198 mm(2)) and the other groups.

CONCLUSION

It seems that the combination of thyroxine and prostaglandin E2, with a synergistic effect, would decrease the root resorption and increase the rate of orthodontic tooth movement in rats.

Commentary: Intermittent teriparatide enhancement of bone graft healing in a rat model of spinal glucocorticoid-induced osteoporosis

Sugiura T, Kashii M, Matsuo Y, Morimoto T, Honda H, Kaito T, et al. Intermittent administration of teriparatide enhances graft bone healing and accelerates spinal fusion in rats with glucocorticoid-induced osteoporosis. Spine J 2015;15:298-306 (in this issue).

Predictors of re-fracture amongst patients managed within a secondary fracture prevention program: a 7-year prospective study

SUMMARY

This 7-year prospective observational study determined the predictors of re-fracture amongst 234 patients managed within a Secondary Fracture Prevention programme. Poor compliance, multiple co-morbidities, corticosteroid therapy, low hip bone mineral density (BMD) or low body weight were all significantly associated with re-fracture in patients commenced on long-term anti-resorptive therapy.

INTRODUCTION

Risk factors for osteoporotic fracture amongst treatment-naïve patients are well established. In contrast, predictors of re-fracture in patients optimally managed within a Secondary Fracture Prevention (SFP) programme are ill-defined.

METHODS

This prospective observational study included 234 subjects with incident osteoporotic fractures managed long-term by the Concord SFP programme. Using Cox proportional hazards models, predictors of re-fracture were analysed separately for patients commenced on specific pharmacotherapy (group 1, N=171) and subjects receiving calcium and/or vitamin D supplements only (group 2, N=63). Relevant anthropometric, clinical and technical data were documented at each visit. Compliance and persistence were analysed as time-varying covariates.

RESULTS

During a mean follow-up of 5.2 (range 3.5-7.3) years, 20.9% of all subjects re-fractured (26.3% in group 1, 6.3% in group 2). Multivariate predictors of re-fracture in group 1 were significant co-morbidity (HR 2.04 if >3, 95% CI 1.10-3.79, p=0.024), corticosteroid use (HR 1.75, 95% CI 1.12-2.73, p=0.013) and total hip BMD (HR 1.36 per 0.1 g/cm2 decrease, 95% CI 1.08-1.70, p=0.008). In contrast, gender, prevalent fractures and lumbar spine BMD were not associated with re-fracture. Amongst patients with complete compliance data, a medication possession ratio of ≤50% (HR 3.36, 95% CI 1.32-8.53, p=0.011) and low body weight (HR 1.04 per 1-kg decrease, 95% CI 1.003-1.08, p=0.032) were significantly associated with re-fracture.

CONCLUSIONS

Amongst patients managed within a dedicated SFP programme, poor compliance, multiple co-morbidities, corticosteroid therapy, low hip BMD or low body weight are all associated with increased risk of re-fracture. This subgroup of patients therefore require intensive management including strategies to improve compliance.

Biochemical markers for assessment of calcium economy and bone metabolism: application in clinical trials from pharmaceutical agents to nutritional products

Nutrition plays an important role in osteoporosis prevention and treatment. Substantial progress in both laboratory analyses and clinical use of biochemical markers has modified the strategy of anti-osteoporotic drug development. The present review examines the use of biochemical markers in clinical research aimed at characterising the influence of foods or nutrients on bone metabolism. The two types of markers are: (i) specific hormonal factors related to bone; and (ii) bone turnover markers (BTM) that reflect bone cell metabolism. Of the former, vitamin D metabolites, parathyroid hormone, and insulin-like growth factor-I indicate responses to variations in the supply of bone-related nutrients, such as vitamin D, Ca, inorganic phosphate and protein. Thus modification in bone remodelling, the key process upon which both pharmaceutical agents and nutrients exert their anti-catabolic or anabolic actions, is revealed. Circulating BTM reflect either osteoclastic resorption or osteoblastic formation. Intervention with pharmacological agents showed that early changes in BTM predicted bone loss and subsequent osteoporotic fracture risk. New trials have documented the influence of nutrition on bone-tropic hormonal factors and BTM in adults, including situations of body-weight change, such as anorexia nervosa, and weight loss by obese subjects. In osteoporosis-prevention studies involving dietary manipulation, randomised cross-over trials are best suited to evaluate influences on bone metabolism, and insight into effects on bone metabolism may be gained within a relatively short time when biochemical markers are monitored.

Evaluation and medical management of fragility fractures of the upper extremity

Osteoporosis continues to be a major health condition plaguing the aging population. The major manifestation of osteoporosis, the development of fragility fractures, is a burden both clinically and economically on patients and the nation's health care system, with up to half of all American women sustaining a fragility fracture in their older years. The high frequency of injuries to the distal radius and proximal humerus should lead upper extremity surgeons to take pause and recognize the magnitude of impact these fractures have on their patient population. Recommended interventions span a spectrum of aggressiveness and have various financial implications.

The role of counselling and other factors in compliance of postmenopausal osteoporotic patients to alendronate 70 therapy

INTRODUCTION

The aim of the study was to assess the role of patient counselling, nurse assistance and effects of biochemical examinations in adherence of women with postmenopausal osteoporosis to alendronate 70 administration over 12 months of therapy.

MATERIAL AND METHODS

Compliance and persistence to alendronate 70 therapy were assessed in a prospective study of 123 postmenopausal women, followed up for one year. The patients were divided into 4 groups (controls, counselled group, biochemical group and nurse assisted group) with monitoring every 6 months; in the nurse assisted group, additional phone contacts were made after 3 and 9 months of treatment. After 12 months, compliance and persistence were analysed. The medication possession ratio (MPR) was regarded as optimal when its value exceeded 80%.

RESULTS

The compliance to alendronate 70 therapy was 54.03% in the control group and the mean persistence with medication was 197 days. The MPR above 80% was observed in 37.5%, and, after 1 year, 43.75% of patients were found persistent with the therapy. In the remaining groups, both compliance and persistence were higher but not statistically significantly, compared to the control group. Neither patient's age, education, diet, nor physical activity influenced the compliance with prescribed therapy. The most common reason to discontinue therapy was either its side effects or smoking.

CONCLUSIONS

The obtained results suggest that better adherence with medical recommendations is observed in patients who receive additional attention, e.g. counselling, biochemical tests or nursing care. The critical elements for therapy discontinuation were side effects and smoking.

Models of care for the secondary prevention of osteoporotic fractures: a systematic review and meta-analysis

Most people presenting with incident osteoporotic fractures are neither assessed nor treated for osteoporosis to reduce their risk of further fractures, despite the availability of effective treatments. We evaluated the effectiveness of published models of care for the secondary prevention of osteoporotic fractures. We searched eight medical literature databases to identify reports published between 1996 and 2011, describing models of care for secondary fracture prevention. Information extracted from each publication included study design, patient characteristics, identification strategies, assessment and treatment initiation strategies, as well as outcome measures (rates of bone mineral density (BMD) testing, osteoporosis treatment initiation, adherence, re-fractures and cost-effectiveness). Meta-analyses of studies with valid control groups were conducted for two outcome measures: BMD testing and osteoporosis treatment initiation. Out of 574 references, 42 articles were identified as analysable. These studies were grouped into four general models of care-type A: identification, assessment and treatment of patients as part of the service; type B: similar to A, without treatment initiation; type C: alerting patients plus primary care physicians; and type D: patient education only. Meta-regressions revealed a trend towards increased BMD testing (p = 0.06) and treatment initiation (p = 0.03) with increasing intensity of intervention. One type A service with a valid control group showed a significant decrease in re-fractures. Types A and B services were cost-effective, although definition of cost-effectiveness varied between studies. Fully coordinated, intensive models of care for secondary fracture prevention are more effective in improving patient outcomes than approaches involving alerts and/or education only.

Peptide-based delivery to bone

Peptides are attractive as novel therapeutic reagents, since they are flexible in adopting and mimicking the local structural features of proteins. Versatile capabilities to perform organic synthetic manipulations are another unique feature of peptides compared to protein-based medicines, such as antibodies. On the other hand, a disadvantage of using a peptide for a therapeutic purpose is its low stability and/or high level of aggregation. During the past two decades, numerous peptides were developed for the treatment of bone diseases, and some peptides have already been used for local applications to repair bone defects in the clinic. However, very few peptides have the ability to form bone themselves. We herein summarize the effects of the therapeutic peptides on bone loss and/or local bone defects, including the results from basic studies. We also herein describe some possible methods for overcoming the obstacles associated with using therapeutic peptide candidates.

Skin anti-aging strategies

Skin aging is a complex biological process influenced by a combination of endogenous or intrinsic and exogenous or extrinsic factors. Because of the fact that skin health and beauty is considered one of the principal factors representing overall "well-being" and the perception of "health" in humans, several anti-aging strategies have been developed during the last years. It is the intention of this article to review the most important anti-aging strategies that dermatologists have nowadays in hand, including including preventive measurements, cosmetological strategies, topical and systemic therapeutic agents and invasive procedures.

Mechanisms for the bone anabolic effect of parathyroid hormone treatment in humans

Intermittent low-dose treatment with parathyroid hormone (PTH) analogues has become widely used in the treatment of severe osteoporosis. During normal physiological conditions, PTH stimulates both bone formation and resorption, and in patients with primary hyperparathyroidism, bone loss is frequent. However, development of the biochemical measurement of PTH in the 1980s led us to understand the regulation of PTH secretion and calcium metabolism which subsequently paved the way for the use of PTH as an anabolic treatment of osteoporosis as, when given intermittently, it has strong anabolic effects in bone. This could not have taken place without the basic understanding achieved by the biochemical measurements of PTH. The stimulatory effects of PTH on bone formation have been explained by the so-called 'anabolic window', which means that during PTH treatment, bone formation is in excess over bone resorption during the first 6-18 months. This is due to the following: (1) PTH up-regulates c-fos expression in bone cells, (2) IGF is essential for PTH's anabolic effect, (3) bone lining cells are driven to differentiate into osteoblasts, (4) mesenchymal stem cells adhesion to bone surface is enhanced, (5) PTH has a direct antiapoptotic effect on osteoblasts and (6) when PTH interferes with remodelling, the osteoblasts over-compensate, and (7) PTH also decreases sclerostin levels, thereby removing inhibition of Wnt signalling which is required for PTH's anabolic actions. Thus, the net formative effect of PTH given in intermittent treatment emerges through a complex network of pathways. In summary, the effects of PTH on bone turnover are dependent on the mode and dose of administration and studies investigating the mechanisms underlying this effect are reviewed in this article.

Bone mineral density (BMD) and osteoporosis risk factor in Egyptian male and female battery manufacturing workers

The study was conducted to estimate the relation between lead exposure and the risk of various symptoms of osteoporosis in male and female battery manufacturing workers by using dual energy X-ray absorptiometry. A total of 18 female and 24 male workers were chosen with the same age range, duty hours per day, work history and weight. A total of 15 healthy controls were chosen with no previous history of bone illness and normal blood lead concentration. Blood lead concentration was measured in all workers and controls. Non-lead elevated subjects were excluded. Bone mineral density was measured by X-ray-based dual-energy X-ray absorptiometry scan machine. Spine, femur neck and radius sites were studied. Results showed that both male and female workers recorded significant elevated levels of lead concentration accompanied by osteoporosis when compared with control. Interestingly, the data revealed that fracture risk in female was significantly higher than male workers. It was concluded that lead poisoning may act as osteoporosis risk factor or co-factor in female workers by activating the conversion of osteopenia to osteoporosis.

[Pharmacologic treatment of osteoporosis--2011]

Osteoporosis affects approximately 9% of the population in Hungary resulting in about 100 000 osteoporotic fractures annually. Thirty-five percent of patients with hip fractures due to osteoporosis will die within 1 year. Direct costs of osteoporosis exceed 25 billion forints per year. Apparently, cost-effective reduction of bone loss and consequent fracture risk will add up to not only financial savings but improvement in quality of life, as well. A number of pharmacological modalities are available for this purpose. The mainstay of the treatment of osteoporosis is the bisphosphonate group that includes effective anti-resorptive compounds mitigating bone loss and fragility. The recently registered denosumab exhibits similar efficacy by neutralizing RANK ligand, however, marked differences can be observed between the two drug classes. Strontium has a unique mechanism of action by rebalancing bone turnover, and thus, providing an efficient treatment option for the not fast bone losers who are at high fracture risk. The purely anabolic teriparatide is available for the extremely severe osteoporotic patients and for those who do not respond to other types of therapy. Older treatment options such as hormone replacement therapy, raloxifene, tibolone or calcitonin may also have a restricted place in the management of osteoporosis.

The effect of vitamin D receptor BsmI genotype on the response to osteoporosis treatment in postmenopausal women: a pilot study

AIM

The purpose of our study was to investigate the possible effect of BsmI vitamin D receptor (VDR's) polymorphism on changes in bone mineral density (BMD) and bone turnover markers in postmenopausal women receiving different treatments.

MATERIAL AND METHODS

This pilot study included 42 postmenopausal women with elevated fracture risk, randomized into 1-year treatment with weekly oral alendronate or daily subcutaneous teriparatide. Both groups received daily supplements of 1000 mg calcium and 800 IU vitamin D. Blood samples were obtained for biochemical evaluation and genotyping. BMD at the lumbar spine and femoral neck were assessed with dual energy X-ray absorptiometry. Baseline, follow-up BMD and markers of bone turnover were assessed according to the BsmI genotype.

RESULTS

BMD at the lumbar spine increased in patients carrying at least one b allele, while it decreased in patients with the BB genotype (P = 0.041). Whereas no gene-treatment interaction was observed in teriparatide-receiving patients, women with the BB genotype receiving alendronate resulted in negative BMD (-0.056 ± 0.032 g/m(2) ) and T-score (-0.295 ± 0.190) gradient, compared to carriers of the b allele (BMD: +0.020 ± 0.017 g/m(2) , P = 0.054; T-score: +0.217 ± 0.100, P = 0.030). No effect of genotype was apparent with respect to gradients of biochemical bone markers.

CONCLUSIONS

These preliminary results indicate that alendronate has a differential effect on BMD, depending on the VDR genotype. Carriers of the b allele may be more responsive to treatment compared to patients with the BB genotype. The interaction of VDR's BsmI polymorphism with the efficacy of the anti-osteoporotic treatment needs further investigation by larger prospective studies.

Use of recombinant human parathyroid hormone(1-84) in patients with postmenopausal osteoporosis: a prospective, open-label, single-arm, multicentre, observational cohort study of the effects of treatment on quality of life and pain--the PROPOSE study

BACKGROUND AND OBJECTIVE

Osteoporosis is a progressive bone disorder. Its medical therapy typically involves calcium, vitamin D and antiresorptive drugs. The anabolic parathyroid hormones (PTHs) represent a major advance since they stimulate new bone formation. Two forms of recombinant human PTH (rhPTH) have been evaluated: the 34-amino acid fragment rhPTH(1-34) and the intact 84-amino acid form rhPTH(1-84), the latter being marketed as Preotact®. Osteoporosis leads to increased bone fragility and susceptibility to fracture. Additionally, the disease is often accompanied by pain and a reduced quality of life (QOL). These aspects have rarely been addressed in previously published studies of PTH, which have instead focused on bone density and fractures. The aim of the present study was to evaluate therapy with rhPTH(1-84) in the treatment of osteoporosis in postmenopausal women under everyday practice conditions with emphasis on patients' QOL and pain.

METHODS

The study was performed as a prospective, open-label, single-arm, multicentre, observational cohort study that included postmenopausal women in whom treatment with rhPTH(1-84) was newly initiated. Patients were to be treated with rhPTH(1-84) for 12 months at a dose of 100 μg, administered once daily as a subcutaneous injection. The primary efficacy endpoint was the total score on the Quality of Life Questionnaire of the European Foundation for Osteoporosis, 41-item version (QUALEFFO-41). Secondary efficacy criteria were QUALEFFO-41 subscale scores, patients' assessments of pain on visual analogue scales (range 0-100), and performance on the chair rising test.

RESULTS

112 patients were included in the safety and in the intent-to-treat (ITT) efficacy analyses. Sixty-six patients finished the 1-year period (per-protocol group). All ITT patients were female with a mean age of 72 years and a mean duration of osteoporosis of 73 months. During the study, all QUALEFFO-41 scales improved significantly: in the ITT group, the mean total score improved from 49.8 to 41.3 points. In the ITT population, mean pain at rest improved significantly by about 20% and mean pain on movement by about 36%. When patients who took at least one dose of pain medication were compared with those who took no pain medication during the study, it was evident that pain reduction did not occur only as a result of taking pain medication: use of rhPTH(1-84) was associated with a similar pain reduction in both subgroups. The most frequent adverse events (AEs) were hypercalcaemia (12.5% of patients) and nausea and vomiting (10.7% of patients). AEs caused 16% of patients to discontinue during the 12-month study period.

CONCLUSION

This 12-month study carried out in a typical sample of postmenopausal women with osteoporosis showed that treatment with rhPTH(1-84) is safe. The present study, which is one of the first to investigate QOL and pain during PTH treatment systematically, also showed that rhPTH(1-84) improves QOL and reduces pain, thereby reducing the burden of osteoporotic symptoms for patients. These results, however, need to be verified in a controlled clinical trial. [ClinicalTrials.gov Identifier: NCT00515593].

Molecular basis of parathyroid hormone receptor signaling and trafficking: a family B GPCR paradigm

The parathyroid hormone (PTH) receptor type 1 (PTHR), a G protein-coupled receptor (GPCR), transmits signals to two hormone systems-PTH, endocrine and homeostatic, and PTH-related peptide (PTHrP), paracrine-to regulate different biological processes. PTHR responds to these hormonal stimuli by activating heterotrimeric G proteins, such as G(S) that stimulates cAMP production. It was thought that the PTHR, as for all other GPCRs, is only active and signals through G proteins on the cell membrane, and internalizes into a cell to be desensitized and eventually degraded or recycled. Recent studies with cultured cell and animal models reveal a new pathway that involves sustained cAMP signaling from intracellular domains. Not only do these studies challenge the paradigm that cAMP production triggered by activated GPCRs originates exclusively at the cell membrane but they also advance a comprehensive model to account for the functional differences between PTH and PTHrP acting through the same receptor.

Changes in trabecular and cortical bone microarchitecture at peripheral sites associated with 18 months of teriparatide therapy in postmenopausal women with osteoporosis

We used high-resolution peripheral quantitative computed tomography (HR-pQCT) to monitor changes in bone microarchitecture and strength at the distal radius and tibia associated with 18 months of teriparatide therapy in postmenopausal women with osteoporosis. Despite treatment-associated declines in total and cortical BMD, trabecular thinning and reduced trabecular bone volume, bone strength did not change significantly from baseline.

INTRODUCTION

Teriparatide is an established anabolic therapy for osteoporosis; however, treatment effects at the distal radius are unclear. Therefore, we aimed to monitor changes in bone microarchitecture and estimated strength at the distal radius and tibia in osteoporotic postmenopausal women.

METHODS

We used high-resolution peripheral quantitative computed tomography (Scanco Medical, Switzerland) to perform a standard three-dimensional morphological analysis of the distal radius and tibia in 11 osteoporotic postmenopausal women (mean age, 68.7 ± 12.7 years) at baseline, 6, 12, and 18 months after initiation of 20 μg/day of teriparatide. Ten of the women received bisphosphonate therapy prior to starting on teriparatide. In addition to the standard analysis, we quantified cortical bone mineral density (BMD), porosity, and thickness using an automated segmentation procedure and estimated bone strength (ultimate stress) using finite element analysis.

RESULTS

After 18 months, we observed a decrease in total BMD (p = 0.03) at the distal radius and a decrease in cortical BMD at the distal radius (p = 0.05) and tibia (p = 0.01). The declines in cortical BMD were associated with trends for increased cortical porosity at both sites. At the distal radius, 18 months of teriparatide treatment was also associated with trabecular thinning (p = 0.009) and reduced trabecular bone volume ratio (p = 0.08). We observed similar trends at the distal tibia. Despite these changes in bone quality, bone strength was maintained over the 18-month follow-up.

CONCLUSIONS

The observed changes in cortical bone structure are consistent with the effects of parathyroid hormone on intracortical bone remodeling. Controlled trials involving larger sample sizes are required to confirm the effects of teriparatide therapy on trabecular and cortical microarchitecture in the peripheral skeleton.

Usability evaluation of a clinical decision support tool for osteoporosis disease management

Background

Osteoporosis affects over 200 million people worldwide at a high cost to healthcare systems. Although guidelines are available, patients are not receiving appropriate diagnostic testing or treatment. Findings from a systematic review of osteoporosis interventions and a series of focus groups were used to develop a functional multifaceted tool that can support clinical decision-making in osteoporosis disease management at the point of care. The objective of our study was to assess how well the prototype met functional goals and usability needs.

Methods

We conducted a usability study for each component of the tool--the Best Practice Recommendation Prompt (BestPROMPT), the Risk Assessment Questionnaire (RAQ), and the Customised Osteoporosis Education (COPE) sheet--using the framework described by Kushniruk and Patel. All studies consisted of one-on-one sessions with a moderator using a standardised worksheet. Sessions were audio- and video-taped and transcribed verbatim. Data analysis consisted of a combination of qualitative and quantitative analyses.

Results

In study 1, physicians liked that the BestPROMPT can provide customised recommendations based on risk factors identified from the RAQ. Barriers included lack of time to use the tool, the need to alter clinic workflow to enable point-of-care use, and that the tool may disrupt the real reason for the visit. In study 2, patients completed the RAQ in a mean of 6 minutes, 35 seconds. Of the 42 critical incidents, 60% were navigational and most occurred when the first nine participants were using the stylus pen; no critical incidents were observed with the last six participants that used the touch screen. Patients thought that the RAQ questions were easy to read and understand, but they found it difficult to initiate the questionnaire. Suggestions for improvement included improving aspects of the interface and navigation. The results of study 3 showed that most patients were able to understand and describe sections of the COPE sheet, and all considered discussing the information with their physicians. Suggestions for improvement included simplifying the language and improving the layout.

Conclusions

Findings from the three studies informed changes to the tool and confirmed the importance of usability testing on all end users to reduce errors, and as an important step in the development process of knowledge translation interventions.

Parathyroid hormone (1-34) augments spinal fusion, fusion mass volume, and fusion mass quality in a rabbit spinal fusion model

STUDY DESIGN

The posterolateral rabbit spinal fusion model was used to assess the effect of intermittent parathyroid hormone on spinal fusion outcomes.

OBJECTIVE

To test the hypothesis that intermittent parathyroid hormone (PTH) improves spinal fusion outcomes in the rabbit posterolateral spinal fusion model.

SUMMARY OF BACKGROUND DATA

Spinal fusion is the definitive management for spinal deformity or instability, yet despite current technology, 5% to 40% of lumbar fusions result in pseudarthrosis. Animal studies have demonstrated enhanced fracture healing with the use of PTH, but the effect of PTH on spinal fusion is poorly described.

METHODS

Forty-four male New Zealand white rabbits underwent bilateral posterolateral spine fusion (L5-L6 level). Twenty-two rabbits received daily subcutaneous injections of PTH (1-34) (10 microg/kg) and 22 received an injection of saline fluid. All were killed 6 weeks after surgery. L5-L6 vertebral segments were removed and analyzed with manual bending, faxitron radiography, microCT, and histomorphometry.

RESULTS

Manual bending identified fusion in 30% (control) versus 81% (PTH) animals (P < 0.001). A radiographic scoring system ("0" = no bone formation, "5" = full fusion) resulted in an average score of 3.36 (control) versus 4.51 (PTH) (P < 0.001). MicroCT analysis demonstrated a median mass of 3.5 cc (control) (range, 2.25-5.40 cc) versus 6.03 cc (PTH) (range, 4.34-10.58 cc) (P < 0.001). Histology showed a median percentage bone area of 14.3% (control) (n = 12) versus 29.9% (PTH) (n = 15) (P < 0.001). The median percentage cartilage was 2.7% (control) (n = 5) versus 26.6% (PTH) (n = 5) (P < 0.01). Osteoclast quantification revealed median values of 140.5 (control) (n = 6) and 345.0 (PTH) (n = 8) (P < 0.001) respectively, and the percentage of osteoblasts revealed a median value of 31.4% (control) (n = 6) versus 64.4% (PTH) (n = 8) (P < 0.001).

CONCLUSION

Intermittent PTH administration increased posterolateral fusion success in rabbits. Fusion bone mass and histologic determinants were also improved with PTH treatment. PTH has promise for use as an adjunctive agent to improve spinal fusion in clinical medicine.

The ovariectomized, mature rat model of postmenopausal osteoporosis: an assessment of the bone sparing effects of curcumin

Identification of natural health products that might benefit skeletal health could reduce the negative impact of osteoporotic bone fractures upon society. The objectives of this study were to evaluate an animal model of postmenopausal osteoporosis and to search for evidence that curcumin reduces bone mineral losses in a dose-dependent manner when endogenous estrogen levels are reduced. Bone mineral density was measured at the spine, femur and whole body before and at 2, 4 and 6 months after ovariectomy in each of 40 mature rats. Serum osteocalcin and C-telopeptide were measured as indicators of bone formation and resorption rates. Femoral compressive strength was measured at 6 months. Ovariectomy alone resulted in loss of mineral from the spine (p<0.005) and an increase in osteocalcin levels (p<0.05). At the same time, there was an increase in energy to fracture (p<0.01) due to an increased bone size. When ovariectomized animals were given etidronate there was no loss of mineral from the spine, the size of the femur increased (p<0.005), C-telopeptide levels were reduced (p<0.001) and femoral compressive strength increased (p<0.025). Administration of curcumin to ovariectomized animals resulted in changes that were intermediate between those produced by etidronate and by ovariectomy alone. The increase in femur size produced by the highest dose of curcumin was statistically significant (p< 0.01) and curcumin administration resulted in a significant, dose dependent, increase in energy to fracture. Curcumin produces beneficial changes in bone turnover and increases in bone strength using the ovariectomized mature rat model of postmenopausal osteoporosis.

Prolonged signaling at the parathyroid hormone receptor by peptide ligands targeted to a specific receptor conformation

The parathyroid hormone receptor (PTHR) is a class B G protein-coupled receptor that plays critical roles in bone and mineral ion metabolism. Ligand binding to the PTHR involves interactions to both the amino-terminal extracellular (N) domain, and transmembrane/extracellular loop, or juxtamembrane (J) regions of the receptor. Recently, we found that PTH(1-34), but not PTH-related protein, PTHrP(1-36), or M-PTH(1-14) (M = Ala/Aib(1),Aib(3),Gln(10),Har(11),Ala(12),Trp(14),Arg(19)), binds to the PTHR in a largely GTPgammaS-resistant fashion, suggesting selective binding to a novel, high-affinity conformation (R(0)), distinct from the GTPgammaS-sensitive conformation (RG). We examined the effects in vitro and in vivo of introducing the M substitutions, which enhance interaction to the J domain, into PTH analogs extended C-terminally to incorporate residues involved in the N domain interaction. As compared with PTH(1-34), M-PTH(1-28) and M-PTH(1-34) bound to R(0) with higher affinity, produced more sustained cAMP responses in cells, formed more stable complexes with the PTHR in FRET and subcellular localization assays, and induced more prolonged calcemic and phosphate responses in mice. Moreover, after 2 weeks of daily injection in mice, M-PTH(1-34) induced larger increases in trabecular bone volume and greater increases in cortical bone turnover, than did PTH(1-34). Thus, the putative R(0) PTHR conformation can form highly stable complexes with certain PTH ligand analogs and thereby mediate surprisingly prolonged signaling responses in bone and/or kidney PTH target cells. Controlling, via ligand analog design, the selectivity with which a PTH ligand binds to R(0), versus RG, may be a strategy for optimizing signaling duration time, and hence therapeutic efficacy, of PTHR agonist ligands.

Mechanical loading enhances the anabolic effects of intermittent parathyroid hormone (1-34) on trabecular and cortical bone in mice

The separate and combined effects of intermittent parathyroid hormone (iPTH) (1-34) and mechanical loading were assessed at trabecular and cortical sites of mouse long bones. Female C57BL/6 mice from 13 to 19 weeks of age were given daily injections of vehicle or PTH (1-34) at low (20 microg/kg/day), medium (40 microg/kg/day) or high (80 microg/kg/day) dose. For three alternate days per week during the last two weeks of this treatment, the tibiae and ulnae on one side were subjected to a single period of non-invasive, dynamic axial loading (40 cycles at 10 Hz with 10-second intervals between each cycle). Two levels of peak load were used; one sufficient to engender an osteogenic response, and the other insufficient to do so. The whole tibiae and ulnae were analyzed post-mortem by micro-computed tomography with a resolution of 5 microm. Treatment with iPTH (1-34) modified bone structure in a dose- and time-dependent manner, which was particularly evident in the trabecular region of the proximal tibia. In the tibia, loading at a level sufficient by itself to stimulate osteogenesis produced an osteogenic response in the low-dose iPTH (1-34)-treated trabecular bone and in the proximal and middle cortical bone treated with all doses of iPTH (1-34). In the ulna, loading at a level that did not by itself stimulate osteogenesis was osteogenic at the distal site when combined with high-dose iPTH (1-34). At both levels of loading, there were synergistic effects in cortical bone volume of the proximal tibia and distal ulna between loading and high-dose iPTH (1-34). Images of fluorescently labelled bones confirmed that such synergism resulted from increases in both endosteal and periosteal bone formation. No woven bone was induced by iPTH (1-34) or either level of loading alone, whereas the combination of iPTH (1-34) and the "sufficient" level of loading stimulated woven bone formation on endosteal and periosteal surfaces of the proximal cortex in the tibiae. Together, these data suggest that in female C57BL/6 mice, under some but not all circumstances, mechanical loading exerts an osteogenic response with iPTH (1-34) in trabecular and cortical bone.

AA, Acúrcio FDA. Treatment of postmenopausal osteoporosis in women: a systematic review

Osteoporosis, a typical disease of the elderly, has become a frequent and relevant public health problem. Several drugs are available for treatment of osteoporosis, some of which are currently dispensed by the Brazilian Unified National Health System. The objective of this study was to present a systematic review of drugs for treatment of osteoporosis, focusing on the adequacy of clinical protocols based on existing evidence in the scientific literature. We conducted a search for randomized clinical trials in PubMed and LILACS that presented results for bone mineral density, incidence of vertebral fractures, and adverse effects. 32 articles met the review's inclusion criteria. Bisphosphonates were reported to have consistently reduced the risk of vertebral fractures. Hormone replacement therapy showed positive outcomes, but its use has been found to increase the risk of cardiovascular disease and breast cancer. Teriparatide and monofluorophosphate also showed efficacy against osteoporosis. Calcium and vitamin D were given to patients as food supplements.

Sequential treatment with intermittent low-dose human parathyroid hormone (1-34) and bisphosphonate enhances large-size skeletal reconstruction by vascularized bone transplantation

Vascularized bone transplantation enables reconstruction of large skeletal defects, but this process needs a long time. Since short-term intermittent parathyroid hormone (PTH) enhances rat fracture healing, we investigated the effects of 4-week intermittent low-dose (10 microg/kg/day) or high-dose (100 microg/kg/day) PTH followed by 4-week vehicle, low-dose or high-dose intermittent PTH, or zoledronic acid (ZOL, 2 micro/kg/week), a potent bisphosphonate, on large skeletal reconstruction by vascularized tibial grafting in rats. Compared to 8-week vehicle, 8-week low-dose PTH did not significantly increase the serum osteocalcin level as well as the urinary deoxypyridinoline level, while 4-week low-dose or high-dose PTH followed by 4-week ZOL decreased both of these levels. Eight-week PTH increased the bone mass of the graft and strength of the reconstructed skeleton in a dose-dependent manner; notably, the reconstructed skeleton showed an obviously higher response to PTH compared to the contralateral nonoperated femur. In contrast, 4-week PTH followed by 4-week vehicle reduced these effects and caused local bone loss at the host-graft junctions. Four-week PTH followed by 4-week ZOL did not induce such bone loss; however, 4-week high-dose PTH followed by 4-week ZOL caused a large callus in the distal cortical junction. Four-week PTH followed by 4-week ZOL increased the bone mass and strength similarly to 8-week PTH. These preliminary findings suggest, for the first time, that sequential treatment with short-term intermittent low-dose PTH and bisphosphonate as well as long-term intermittent low-dose PTH treatment enhance large skeletal reconstruction by vascularized bone transplantation, though early timing of sequential antiresorptive treatment could result in delay of bone repair.

Enhancement of fracture healing with parathyroid hormone: preclinical studies and potential clinical applications

Parathyroid hormone (PTH) has become the most widely studied hormone with regard to its administration to various species and their respective skeletal responses. Beyond its affirmative effect in osteoporosis treatment, systemic PTH administration seems to stimulate bone formation in the fracture healing process. According to preclinical experimental studies, once-daily administration of PTH enhances the morphometric and mechanical properties of fracture calluses and accelerates the normal fracture healing. Its anabolic effect is obvious even in low doses, as well as in cases of implant fixation and distraction osteogenesis. There is little evidence of toxic effects and there are only a few reports of adverse events related to its use. The incidence of bone neoplasms in animal studies depends on the dose and duration of treatment. However, it is not prognostic of an equivalent risk potential of carcinogenesis in humans. In summary, the clinical promise of parathyroid hormone is very high and a positive effect in fracture healing should be anticipated.