Teriparatide for osteoporosis: importance of the full course

Denosumab ameliorates osteoarthritis by protecting cartilage against degradation and modulating subchondral bone remodeling

Osteoarthritis (OA) is the most prevalent degenerative joint disease worldwide. Effective management for early-stage OA is crucial. Denosumab (DS) has been widely used to treat osteoporosis (OP) and rheumatoid arthritis, but its potential for managing OA remains clear. We assessed the effects of DS on osteoclast activity and chondrocyte apoptosis using tartrate-resistant acid phosphatase (TRAP) assay, quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry, and TUNEL staining. To assess the impact of DS on the NF-κB pathway, we performed Western blot and immunofluorescence staining. Additionally, we used an OA model to explore the influence of DS on subchondral bone remodeling and cartilage degeneration in vivo. We found that DS hindered receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclastogenesis by inhibiting the activity of the NF-κB pathway. Besides, DS alleviated reactive oxygen species (ROS)-induced apoptosis in chondrocytes by regulating the expression of genes related to apoptosis. Moreover, we observed an attenuation of OA-related subchondral bone remodeling and cartilage degeneration in vivo. Our findings indicate that DS could effectively suppress osteoclast activity and chondrocyte apoptosis, thereby mitigating OA-related subchondral bone remodeling and cartilage degeneration. These results provide a mechanistic basis for using DS to treat OA.

Therapeutic avenues in bone repair: Harnessing an anabolic osteopeptide, PEPITEM, to boost bone growth and prevent bone loss

The existing suite of therapies for bone diseases largely act to prevent further bone loss but fail to stimulate healthy bone formation and repair. We describe an endogenous osteopeptide (PEPITEM) with anabolic osteogenic activity, regulating bone remodeling in health and disease. PEPITEM acts directly on osteoblasts through NCAM-1 signaling to promote their maturation and formation of new bone, leading to enhanced trabecular bone growth and strength. Simultaneously, PEPITEM stimulates an inhibitory paracrine loop: promoting osteoblast release of the decoy receptor osteoprotegerin, which sequesters RANKL, thereby limiting osteoclast activity and bone resorption. In disease models, PEPITEM therapy halts osteoporosis-induced bone loss and arthritis-induced bone damage in mice and stimulates new bone formation in osteoblasts derived from patient samples. Thus, PEPITEM offers an alternative therapeutic option in the management of diseases with excessive bone loss, promoting an endogenous anabolic pathway to induce bone remodeling and redress the imbalance in bone turnover.

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.

Current perspectives on the multiple roles of osteoclasts: Mechanisms of osteoclast-osteoblast communication and potential clinical implications

Bone remodeling is a complex process involving the coordinated actions of osteoblasts and osteoclasts to maintain bone homeostasis. While the influence of osteoblasts on osteoclast differentiation is well established, the reciprocal regulation of osteoblasts by osteoclasts has long remained enigmatic. In the past few years, a fascinating new role for osteoclasts has been unveiled in promoting bone formation and facilitating osteoblast migration to the remodeling sites through a number of different mechanisms, including the release of factors from the bone matrix following bone resorption and direct cell-cell interactions. Additionally, considerable evidence has shown that osteoclasts can secrete coupling factors known as clastokines, emphasizing the crucial role of these cells in maintaining bone homeostasis. Due to their osteoprotective function, clastokines hold great promise as potential therapeutic targets for bone diseases. However, despite long-standing work to uncover new clastokines and their effect in vivo, more substantial efforts are still required to decipher the mechanisms and pathways behind their activity in order to translate them into therapies. This comprehensive review provides insights into our evolving understanding of the osteoclast function, highlights the significance of clastokines in bone remodeling, and explores their potential as treatments for bone diseases suggesting future directions for the field.

Teriparatide and clodronate combination as a potential treatment for complex regional pain syndrome type I in delayed consolidation after foot surgery: a case report and review of the literature

BACKGROUND

Complex regional pain syndrome type I is a pathological condition characterized by an exaggerated response of tissues to low or moderate pain stimuli. The exact pathogenesis and optimal medical treatment for complex regional pain syndrome type I are still not fully understood, although bisphosphonates have shown positive effects in reducing pain. Foot surgery can be complicated by the development of complex regional pain syndrome type I, leading to functional decline and difficulties in weight-bearing.

CASE PRESENTATION

The authors present a clinical case involving complex regional pain syndrome type I that developed after surgical foot arthrodesis. The patient, a 42-year-old Caucasian male, did not respond to clodronate treatment but experienced successful outcomes upon the addition of teriparatide, which effectively stimulated the healing of arthrodesis.

CONCLUSION

Teriparatide cannot be considered the primary treatment for complex regional pain syndrome due to insufficient solid clinical data. However, when complex regional pain syndrome is associated with or caused by delayed union, teriparatide can be used to address the underlying cause of complex regional pain syndrome.

Anti-osteoporotic drug efficacy for periprosthetic bone loss after total hip arthroplasty: A systematic review and network meta-analysis

BACKGROUND

Periprosthetic bone loss following total hip arthroplasty (THA) threatens prosthesis stability. This systematic review and network meta-analysis aimed to compare the efficacy of anti-osteoporotic drugs for measures of hip function according to functional outcomes, periprosthetic femoral bone mineral density loss in each Gruen zone, and revision surgery after THA.

METHODS

The systematic search of six literature databases was conducted in December 2021 in accordance with PRISMA guidelines. Adult participants who underwent primary THA were included. A random-effects network meta-analysis was performed within a frequentist framework, and the confidence in the evidence for each outcome was evaluated using the CINeMA tool, which assessed the credibility of results from the network meta-analysis. We included 22 randomized controlled trials (1243 participants) comparing the efficacy and safety of bisphosphonates (including etidronate, clodronate, alendronate, risedronate, pamidronate, and zoledronate), denosumab, selective estrogen receptor modulator, teriparatide, calcium + vitamin D, calcium, and vitamin D. We defined the period for revision surgery as the final follow-up period.

RESULTS

Raloxifene, bisphosphonate, calcium + vitamin D, and denosumab for prosthetic hip function might have minimal differences when compared with placebos. The magnitude of the anti-osteoporotic drug effect on periprosthetic femoral bone loss varied across different Gruen zones. Bisphosphonate, denosumab, teriparatide might be more effective than placebo in Gruen zone 1 at 12 months after THA. Additionally, bisphosphonate might be more effective than placebo in Gruen zones 2, 5, 6, and 7 at 12 months after THA. Denosumab was efficacious in preventing bone loss in Gruen zones 6 and 7 at 12 months after THA. Teriparatide was likely to be efficacious in preventing bone loss in Gruen zone 7 at 12 months after THA. Raloxifene was slightly efficacious in preventing bone loss in Gruen zones 2 and 3 at 12 months after THA. Calcium was slightly efficacious in preventing bone loss in Gruen zone 5 at 12 months after THA. None of the studies reported revision surgery.

CONCLUSIONS

Bisphosphonate and denosumab may be effective anti-osteoporotic drugs for preventing periprosthetic proximal femoral bone loss due to stress shielding after THA, particularly in cementless proximal fixation stems, which are the most commonly used prostheses worldwide.

Osteoporosis therapy using nanoparticles: a review

Osteoporosis, characterized by low bone density and increased risk of fractures, represents a major healthcare challenge. Anti-resorptive and anabolic medications are now used to treat osteoporosis in an effort to reduce bone loss and increase bone mass. Innovative methods are required since current therapies have drawbacks. Promising options for improving bone health and medicine delivery are provided by nanotechnology. Bisphosphonates with tetracyclines and oligopeptides, among other compounds that target the bone, make it easier to provide a particular medication to bone tissue. Additionally, nanocarriers are essential for the administration of both organic and inorganic nanoparticles in the treatment of osteoporosis. Drug encapsulation and controlled release may be done in a variety of ways using organic nanoparticles. Inorganic nanoparticles have special qualities that help in medication transport and bone repair. This review explores the potential of nanoparticle-based strategies in the treatment of osteoporosis.

Beneficial effect and mechanism of natural resourced polysaccharides on regulating bone metabolism through intestinal flora: A review

Bone metabolism is an important biological process for maintaining bone health. Polysaccharides of natural origin exert beneficial effects on bone metabolism. Polysaccharide molecules often have difficulty passing through the intestinal cell membrane and are directly absorbed in the gastrointestinal tract. Therefore, polysaccharides may affect intestinal flora and play a role in disease treatment. We performed a comprehensive review of the relevant literature published from 2003 to 2023. We found that several polysaccharides from traditional Chinese medicines, including Astragalus, Achyranthes bidentata and Eucommia ulmoides, and the polysaccharides from several dietary fibers mainly composed of inulin, resistant starch, and dextran could enrich the intestinal microbiota group to regulate bone metabolism. The promotion of polysaccharide decomposition by regulating the Bacteroides phylum is particularly critical. Studies on the structure-activity relationship showed that molecular weight, glycosidic bonds, and monosaccharide composition may affect the ability of polysaccharides. The mechanism by which polysaccharides regulate intestinal flora to enhance bone metabolism may be related to the regulation of short-chain fatty acids, immunity, and hormones, involving some signaling pathways, such as TGF-β, Wnt/β-catenin, BMP/Smads, and RANKL. This paper provides a useful reference for the study of polysaccharides and suggests their potential application in the treatment of bone metabolic disorders.

The Mechanotransduction Signaling Pathways in the Regulation of Osteogenesis

Bones are constantly exposed to mechanical forces from both muscles and Earth's gravity to maintain bone homeostasis by stimulating bone formation. Mechanotransduction transforms external mechanical signals such as force, fluid flow shear, and gravity into intracellular responses to achieve force adaptation. However, the underlying molecular mechanisms on the conversion from mechanical signals into bone formation has not been completely defined yet. In the present review, we provide a comprehensive and systematic description of the mechanotransduction signaling pathways induced by mechanical stimuli during osteogenesis and address the different layers of interconnections between different signaling pathways. Further exploration of mechanotransduction would benefit patients with osteoporosis, including the aging population and postmenopausal women.

Exercise for optimizing bone health after hormone-induced increases in bone stiffness

Hormones and mechanical loading co-regulate bone throughout the lifespan. In this review, we posit that times of increased hormonal influence on bone provide opportunities for exercise to optimize bone strength and prevent fragility. Examples include endogenous secretion of growth hormones and sex steroids that modulate adolescent growth and exogenous administration of osteoanabolic drugs like teriparatide, which increase bone stiffness, or its resistance to external forces. We review evidence that after bone stiffness is increased due to hormonal stimuli, mechanoadaptive processes follow. Specifically, exercise provides the mechanical stimulus necessary to offset adaptive bone resorption or promote adaptive bone formation. The collective effects of both decreased bone resorption and increased bone formation optimize bone strength during youth and preserve it later in life. These theoretical constructs provide physiologic foundations for promoting exercise throughout life.

Real-World Effectiveness of Osteoporosis Medications in France: A Nationwide Cohort Study

Although drugs for osteoporosis have been demonstrated to be effective in reducing fracture risk in placebo-controlled clinical trials, data on effectiveness in real-world practice is limited. Data from the French national health insurance claims database (SNDS) were used to follow five cohorts of women aged ≥55 years after initiating treatment for ≥6 months with either denosumab, zoledronic acid, oral bisphosphonates, raloxifene, or teriparatide in 2014-2016. Fracture incidence was compared within each cohort between the 3 months following initiation (baseline fracture risk) and the 12month, 18month, and 24 month postinitiation periods. Data are presented as incidence rate ratios (IRRs) with their 95% confidence intervals (CIs)s. Overall, 67,046 women were included in the denosumab cohort, 52,914 in the oral bisphosphonate cohort, 41,700 in the zoledronic acid cohort, 11,600 in the raloxifene cohort, and 7510 in the teriparatide cohort. The baseline vertebral fracture rate ranged from 1.74 per 1000 person years (‰PY) in the raloxifene cohort to 34.75‰PY in the teriparatide cohort, and the baseline hip fracture rate from 0.70‰PY in the raloxifene cohort to 10.52‰PY in the zoledronic acid cohort. Compared with the baseline fracture rate, vertebral fractures involving hospitalization were significantly reduced in the 3-24-month postinitiation period with denosumab (IRR 0.6; 95% CI, 0.5-0.7), zoledronic acid (IRR 0.4; 95% CI, 0.3-0.4), teriparatide (IRR 0.3; 95% CI, 0.2-0.5), and oral bisphosphonates (IRR 0.6; 95% CI, 0.4-0.8). Hip fracture incidence was reduced with denosumab (IRR 0.8; 95% CI, 0.6-0.9), but higher for oral bisphosphonates (IRR 1.7; 95% CI, 1.2-2.3); no significant change in hip fracture rate was observed for zoledronic acid, teriparatide, or raloxifene. A reduction in nonvertebral, non-hip fracture incidence was observed only in the denosumab cohort (IRR 0.8; 95% CI, 0.7-0.9). These findings indicate that treatment with osteoporosis drugs is effective in the real-world setting. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Using sequential pharmacotherapy for the treatment of osteoporosis: an update of the literature

INTRODUCTION

Osteoporosis, which is characterized by compromised bone density and heightened susceptibility to fractures, is a substantial public health concern, especially among the aging population. Underdiagnosis, undertreatment, and therapy non-adherence contribute to its impact. Anabolic and dual-action agents like teriparatide, abaloparatide, and romosozumab have emerged as effective treatments, allowing rapid gains in bone mineral density (BMD) and reducing fracture risk. However, administering treatments in the correct order is paramount, with an 'anabolic first' approach gaining traction for patients at high risk of fractures. This strategy involves starting anabolic therapies, followed by antiresorptive agents as maintenance therapy. It is important to note that the effectiveness of anabolic agents differs between treatment-naive and previously treated patients: tailored treatment approaches are therefore necessary. This comprehensive strategy adheres to clinical guidelines, emphasizing individualized care, early intervention, and patient-centered management to mitigate the burden of osteoporosis and enhance patients' quality of life.

AREA COVERED

The aim of this review is to summarize recent evidence on the sequential treatment of osteoporosis and to provide recommendations on the best treatment strategies.

EXPERT OPINION

Effective treatments, such as anabolic agents, are key in high-risk patients, who require an 'anabolic first' approach. Sequential therapy, specifically tailored to a patient's history, can help to optimize prevention and management of fractures.

Effects of Teriparatide Treatment on Bone Mineral Density in Patients With Osteoporosis: A Short-Term Dose-Response Study

INTRODUCTION

Osteoporosis is a chronic bone disease that develops with a decrease in bone mineral density (BMD) along with bone mass. An essential measure in the prevention of osteoporosis is the achievement of normal peak bone mass. Teriparatide (TPTD) functions as an osteoanabolic agent, exerting a dual influence on bone remodeling by modulating both osteogenesis and osteoclastogenesis. Bone mass is determined by dual-energy x-ray absorptiometry (DEXA) quantitative CT scan and has outstanding precision (within 1% to 2%) and has the ability to show the effectiveness of drug intervention.

OBJECTIVE

To assess the effectiveness of TPTD treatment on BMD in osteoporosis patients.

MATERIALS AND METHODS

The study is a retrospective, observational, multi-center study of 378 osteoporosis patients who were treated with 20 µg of subcutaneous TPTD every day for six months. DEXA scores of the hip joints of patients were measured both before and after TPTD treatment.

RESULTS

 The DEXA scores of the total population pre and post-treatment were -2.75+0.58 and -2.15+0.95 respectively, with a p-value of <0.001, which is statistically significant. In women the pre and post-treatment scores were -2.728+0.52 and -2.276+0.49, with a significant p-value of <0.001 whereas in males, the scores were -2.756+0.72 and -2.108+1.29 respectively, with a significant p-value of <0.05.

CONCLUSION

The six-month treatment with TPTD significantly improved DEXA scores in osteoporosis patients. DEXA score's precision and sensitivity in quantifying impact contribute to effective osteoporosis management, guiding treatment strategies for better outcomes in the Indian population. Further research is warranted to see the long-term effect of TPTD.

Sequential treatment of teriparatide and alendronate versus alendronate alone for elevation of bone mineral density and prevention of refracture after percutaneous vertebroplasty in osteoporosis: a prospective study

BACKGROUND

Percutaneous vertebroplasty was the most common strategy for osteoporotic vertebral compression fracture. However, refracture after vertebroplasty also occurred and bone mineral density (BMD) was one of the main factors associated with refracture after percutaneous vertebroplasty.

AIMS

To investigate the efficacy of a short-sequential treatment of teriparatide followed by alendronate on prevention of refracture after percutaneous vertebroplasty in osteoporotic patients, and compare it with the therapy of alendronate alone.

METHODS

From January 2018 to January 2020, we recruited 165 female osteoporosis patients after percutaneous vertebroplasty who were assigned into sequential treatment of teriparatide followed by alendronate group (TPTD + ALN group) and alendronate alone group (ALN group). The vertebral fracture occurred during this process was also recorded in both the groups. A total of 105 participants completed the 1-year follow-up. Furthermore, BMD and serum procollagen type I N-terminal propeptide (PINP) and C-terminal cross-linking telopeptide of type I collagen (CTX) were compared between the two groups during 1-year follow-up.

RESULTS

The 105 patients were finally included, with 59 in ALN group and 46 in TPTD + ALN group. During 1-year follow-up, the vertebral refracture rate in TPTD + ALN group was much lower than that in ALN group (2.2% vs. 13.6%, p < 0.05). At 12 months, the BMDs at lumbar in TPTD + ALN group were significantly elevated when compared to the ALN group (0.65 ± 0.10 vs. 0.57 ± 0.07, p < 0.001).

DISCUSSION AND CONCLUSION

A short-sequential administration of teriparatide followed by alendronate was more effective in elevating the BMD and decreasing the refracture rate at 12-month follow-up, compared to the counterpart with alendronate alone.

Oxidative Stress and Natural Antioxidants in Osteoporosis: Novel Preventive and Therapeutic Approaches

This review reports in detail the cellular and molecular mechanisms which regulate the bone remodeling process in relation to oxidative stress (OS), inflammatory factors, and estrogen deficiency. OS is considered an important pathogenic factor of osteoporosis, inducing osteocyte apoptosis and varying levels of specific factors, such as receptor activator κB ligand (RANKL), sclerostin, and, according to recent evidence, fibroblast growth factor 23, with consequent impairment of bone remodeling and high bone resorption. Bone loss increases the risk of fragility fractures, and the most commonly used treatments are antiresorptive drugs, followed by anabolic drugs or those with a double effect. In addition, recent data show that natural antioxidants contained in the diet are efficient in preventing and reducing the negative effects of OS on bone remodeling and osteocytes through the involvement of sirtuin type 1 enzyme. Indeed, osteocytes and some of their molecular factors are considered potential biological targets on which antioxidants can act to prevent and reduce bone loss, as well as to promote bone anabolic and regenerative processes by restoring physiological bone remodeling. Several data suggest including antioxidants in novel therapeutic approaches to develop better management strategies for the prevention and treatment of osteoporosis and OS-related bone diseases. In particular, anthocyanins, as well as resveratrol, lycopene, oleuropein, some vitamins, and thiol antioxidants, could have protective and therapeutic anti-osteoporotic effects.

The pH-responsive precipitation-redissolution of the CspB fusion protein, CspB50TEV-Teriparatide, triggered by changes in secondary structure

Cell surface protein B (CspB) fusion proteins can undergo reversible pH-responsive precipitation-redissolution. A pH-responsive precipitation-redissolution of CspB tag purification (pPRCP) method was established for protein purification using this property. However, the mechanism of the pH-responsive precipitation of CspB fusion proteins is unknown, which has made it difficult to set process parameters for pPRCP. In this study, we investigated the mechanism of the pH-responsive precipitation of CspB fusion proteins using CspB50TEV-Teriparatide (CspB-teri) as a model. As expected, CspB-Teri was reversibly precipitated at acidic pH. By contrast, CspB-Teri was not precipitated under unfolding conditions induced by trifluoroethanol, urea, or guanidine hydrochloride, even at acidic pH. The conformation of CspB-Teri changed to a β-sheet-rich structure as the pH decreased, followed by the formation of intermolecular interactions, which caused precipitation. The particle size of the CspB-Teri precipitate increased in a protein concentration-dependent manner. These results indicated that the pH-responsive precipitation of CspB-Teri is triggered by the formation of a β-sheet structure in response to decreasing pH, and the growth of the precipitate particles occurred through intermolecular interactions.

Effect of Teriparatide on Bone Mineral Density and Bone Markers in Real-Life: Argentine Experience

PURPOSE

To evaluate the effect of teriparatide (TPTD) on bone mineral density (BMD) and bone markers under clinical practice conditions. To assess whether the results in real-life match those published in clinical trials.

METHODS

Cross-sectional study of postmenopausal women treated with TPTD for at least 12 months.

RESULTS

264 patients were included in the study. Main characteristics are as follows: age: 68.7 ± 10.2 years, previous fractures: 57.6%, and previously treated with antiresorptive (AR-prior): 79%. All bone turnover markers studied significantly increased after 6 months. CTX and BGP remained high up to 24 months, but total and bone alkaline phosphatase returned to basal values at month 18. There was a significant increase in lumbar spine (LS) BMD after 6 months (+6.2%), with a maximum peak at 24 months (+13%). Femoral neck (FN) and total hip (TH) BMD showed a significant increase later than LS (just at month 12), reaching a maximum peak at month 24 (FN + 7.9% and TH + 5.5%). A significant increase in LS BMD was found from month 6 to month 24 compared to basal in both AR-naïve, and AR-prior patients (+16.7% and +10.5%, respectively), without significant differences between the two groups. Comparable results were found in FN and TH BMD. Main conclusions. As reported in real-life clinical studies, treatment of osteoporotic postmenopausal women with TPTD induced a significant increase in bone turnover markers from month 6 onward and an increase in BMD from months 6-12 with continuous gain up to month 24. The real-life results of our study matched the results of randomized clinical trials. In addition, TPTD induced an increase in BMD, regardless of the previous use of AR.

How Has Molecular Biology Enhanced Our Undertaking of axSpA and Its Management

PURPOSE

This review aims at investigating pathophysiological mechanisms in spondyloarthritis (SpA). Analysis of genetic factors, immunological pathways, and abnormalities of bone metabolism lay the foundations for a better understanding of development of the axial clinical manifestations in patients, allowing physician to choose the most appropriate therapeutic strategy in a more targeted manner.

RECENT FINDINGS

In addition to the contribution of MHC system, findings emerged about the role of non-HLA genes (as ERAP1 and 2, whose inhibition could represent a new therapeutic approach) and of epigenetic mechanisms that regulate the expression of genes involved in SpA pathogenesis. Increasing evidence of bone metabolism abnormalities secondary to the activation of immunological pathways suggests the development of various bone anomalies that are present in axSpA patients. SpA are a group of inflammatory diseases with a multifactorial origin, whose pathogenesis is linked to the genetic predisposition, the action of environmental risk factors, and the activation of immune response. It is now well known how bone metabolism leads to long-term structural damage via increased bone turnover, bone loss and osteoporosis, osteitis, erosions, osteosclerosis, and osteoproliferation. These effects can exist in the same patient over time or even simultaneously. Evidence suggests a cross relationship among innate immunity, autoimmunity, and bone remodeling in SpA, making treatment approach a challenge for rheumatologists. Specifically, treatment targets are consistently increasing as new drugs are upcoming. Both biological and targeted synthetic drugs are promising in terms of their efficacy and safety profile in patients affected by SpA.

Paracrine and endocrine functions of osteocytes

Osteocytes are dendritic-shaped cells embedded in the bone matrix and are terminally differentiated from osteoblasts. Inaccessibility due to their location has hindered the understanding of the molecular functions of osteocytes. However, scientific advances in the past few decades have revealed that osteocytes play critical roles in bone and mineral metabolism through their paracrine and endocrine functions. Sclerostin produced by osteocytes regulates bone formation and resorption by inhibiting Wnt/β-catenin signaling in osteoblast-lineage cells. Receptor activator of nuclear factor κ B ligand (RANKL) derived from osteocytes is essential for osteoclastogenesis and osteoclast activation during postnatal life. Osteocytes also secrete fibroblast growth factor 23 (FGF23), an endocrine FGF that regulates phosphate metabolism mainly by increasing phosphate excretion and decreasing 1, 25-dihydroxyvitamin D production in the kidneys. The regulation of FGF23 production in osteocytes is complex and multifactorial, involving many local and systemic regulators. Antibodies against sclerostin, RANKL, and FGF23 have emerged as new strategies for the treatment of metabolic bone diseases. Improved undrstanding of the paracrine and endocrine functions of osteocytes will provide insight into future therapeutic options.

Improvement in Glucocorticoid-Induced Osteoporosis on Switching from Bisphosphonates to Once-Weekly Teriparatide: A Randomized Open-Label Trial

This randomized, open-label, multicenter, parallel study imitating real-world clinical practice assessed the effect of switching to weekly teriparatide in patients with glucocorticoid-induced osteoporosis (GIO) with a lumbar spine/proximal femur bone mineral density (BMD) T-score ≤ -2.0 or ≤-1.0 and a fragility fracture. Forty-four patients were randomized. The mean durations of the corticosteroid and bisphosphonate administrations were 90.0 and 51.3 months. The baseline BMD at L1-L4 was 0.828 and 0.826 g/cm² in Groups B (bisphosphonate) and T (teriparatide); at the femur (total), these values were 0.689 and 0.661 g/cm². The mean change in BMD was numerically higher with teriparatide vs. bisphosphonate but not statistically significant. The mean percentage changes from baseline in BMD at L1-L4 after a 72-week treatment were 0.5% and 4.1% in Groups B and T. The incidence of new fractures was higher in the patients taking bisphosphonates vs. those receiving once-weekly teriparatide at 72 weeks (18.2% vs. 11.8%) and 144 weeks (22.7% vs. 17.6%). The mean percentage change in femur (trochanter) BMD (0.035 [0.007-0.063]; p = 0.02) was significantly greater with teriparatide vs. bisphosphonates. Adverse events (AEs) were more frequent with teriparatide vs. bisphosphonates. Switching to once-weekly teriparatide tended to increase lumbar spine BMD and reduce the occurrence of new fractures vs. bisphosphonates.

Abaloparatide and teriparatide enhance mandibular growth in adolescent rats with site-specific and mechano-related effects

OBJECTIVE

Teriparatide (TPTD) and abaloparatide (ABL) are two osteoanabolic drugs targeting parathyroid hormone (PTH)1R signalling. This study aimed to investigate the effects of TPTD and ABL on the adolescent mandibular growth.

METHOD

In total, 70 4-week-old male Sprague-Dawley rats were randomly divided into 14 groups, treated with intermittent TPDT or ABL at various doses, accompanied by mandibular advancement (MA) or not. 3D printing was used to fabricate an innovative splint for MA. After a 4-week treatment, morphological measurement, histological and immunohistochemical analysis were performed. Mandibular condylar chondrocytes (MCCs) were treated with TPTD or ABL, followed by CCK-8 assay, alcian blue staining, real time-PCR and immunofluorescent staining.

RESULT

In vivo, TPTD or ABL alone increased the condylar length and cartilage thickness, with up-regulated SOX9 and COL II, whilst down-regulated COL X; however, when combined with MA, the promotive effects were attenuated. TPTD or ABL alone increased the mandibular body height and mandibular angle width, whilst increased the mandibular body length and alveolar bone width when combined with MA. In vitro, TPTD or ABL enhanced the MCC proliferation, glycosaminoglycan synthesis, COL II and SOX9 expression, whilst down-regulated COL X, Ihh and PTH1R expression.

CONCLUSION

Both ABL and TPTD enhance mandibular growth in adolescent rats with site-specific and mechano-related effects, including propelling chondrogenesis at the condylar cartilage and promoting bone apposition at other mechano-responsive sites. They behave as promising drugs for mandibular growth modification, and in general ABL seems more potent than TPTD in this context.

Quantification of Anti-Osteoporotic Anabolic Peptide in Stealth Lipid Nanovesicles Through Validated RP-HPLC Method

BACKGROUND

Teriparatide is a recombinant fragment of human parathyroid hormone, a potent osteoanabolic agent used for osteoporosis.

OBJECTIVE

The present study endeavored to develop a simple, rapid, and reliable reverse phase-high performance liquid chromatography (RP-HPLC) method for the determination of teriparatide in pegylated lipid nanovesicles for rapid formulation development/optimization.

METHOD

A rapid RP-HPLC-based analytical method was developed for the quantification of teriparatide in pegylated lipid nanovesicles. The method was optimized on a Waters XBridge C18 (4.6 × 150 mm, 10 μm) column with a mobile phase consisting of 0.1% formic acid in water and acetonitrile both in a linear gradient program. In the method, a short run time of 9 min was achieved at a flow rate of 1.0 mL/min with an injection volume of 50 µL at a detection wavelength of 210 nm. The developed method was validated according to the ICH Q2 (R2) guideline. The method was applied for the quantification of teriparatide in prepared pegylated lipid nanovesicles. Teriparatide encapsulated pegylated lipid nanovesicles were prepared by the ethanol injection method. Further, these vesicles were characterized for % entrapment efficiency (%EE), particle size, zeta potential, and morphology by Cryo-SEM.

RESULTS

The teriparatide was eluting at 4.8 min in the run. Further, for the method validation, the linear relationship between concentration and response was established over the concentration range of 50-250 µg/mL with the R2 > 0.999. The method sensitivity was shown with LOD and LOQ with the value of 100 ng/mL and 500 ng/mL, respectively. The method was found to be accurate and precise with the recovery ranging in 100 ± 2% and RSD <2%, respectively. Minor deliberate changes proved the robustness of the developed method.

CONCLUSIONS

These results indicated that the developed and validated method is accurate, precise, rapid, reliable, and fit for the quantification of teriparatide in different formulations.

HIGHLIGHTS

The RP-HPLC method was developed and validated for the quantification of teriparatide from novel pegylated lipid nanovesicles.

An effect comparison of alendronate and teriparatide in patients with glucocorticoid-induced osteoporosis: A protocol for systematic review and meta-analysis

BACKGROUND

Glucocorticoid-induced osteoporosis is the most common secondary cause of osteoporosis and the resulting fractures cause significant morbidity. Oral bisphosphonates are currently regarded as first line options on the grounds of their low cost. However, teriparatide has been shown to be superior in its effects on bone mineral density and vertebral fracture risk in glucocorticoid-treated individuals with osteoporosis. We conducted a protocol for systematic review and meta-analysis to assess the effectiveness of alendronate and teriparatide in patients with glucocorticoid-induced osteoporosis.

METHODS

The study protocol has been registered on international prospective register of systematic review (PROSPERO registration number: CRD42022371561). The procedure of this protocol will be conducted according to the Preferred Reporting Item for Systematic Review and Meta-analysis Protocols guidance. PubMed, EMBASE, MEDLINE, the Cochrane Library, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, Wanfang Database, ClinicalTrials.gov trials registry, and Chinese Clinical Trial Registry will be searched from January 1980 to November 2022. Two authors will assess methodological quality of included studies separately by the Cochrane collaboration's risk of bias tool. We will apply RevMan 5.4 software for statistical analysis.

RESULTS

This study will provide a high-quality comprehensive evaluation of the efficacy and safety of alendronate and teriparatide for treating patients with glucocorticoid-induced osteoporosis.

CONCLUSION

The conclusion of our systematic review will provide evidence to judge whether teriparatide is an effective intervention for patients with glucocorticoid-induced osteoporosis.

Examining the role of cannabinoids on osteoporosis: a review

PURPOSE

Prior research studies have shown that the endocannabinoid system, influenced by CBD and THC, plays a role in bone remodeling. As both the research on cannabis and use of cannabis continue to grow, novel medicinal uses of both its constituents as well as the whole plant are being discovered. This review examines the role of cannabinoids on osteoporosis, more specifically, the endocannabinoid system and its role in bone remodeling and the involvement of the cannabinoid receptors 1 and 2 in bone health, as well as the effects of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and synthetic cannabinoids on bone.

METHODS

A comprehensive literature search of online databases including PUBMED was utilized.

RESULTS

A total of 29 studies investigating the effects of cannabis and/or its constituents as well as the activation or inactivation of cannabinoid receptors 1 and 2 were included and discussed.

CONCLUSION

While many of the mechanisms are still not yet fully understood, both preclinical and clinical studies show that the effects of cannabis mediated through the endocannabinoid system may prove to be an effective treatment option for individuals with osteoporosis.

Anabolic Peptide-Enriched Stealth Nanoliposomes for Effective Anti-Osteoporotic Therapy

The objective of the present work was to develop PTH (1-34)-loaded stealth nanoliposomes (PTH-LPs) by employing the use of the Quality by Design (QbD) approach. Risk identification was carried out using the Ishikawa fishbone diagram. PTH-LPs were optimized using Box Behnken Design, a type of response surface methodology to examine the effect of independent variables on dependent variables such as particle size and percentage entrapment efficiency (%EE). Design space was generated for PTH-LPs to reduce interbatch variability during the formulation development process. Furthermore, a cytotoxicity assay, cell proliferation assay, calcium calorimetric assay, mineralized nodule formation, and cellular uptake assay were carried out on MG-63 osteoblast-like cells. The results obtained from these procedures demonstrated that lipid concentration had a significant positive impact on particle size and %EE, whereas cholesterol concentration showed a reduction in %EE. The particle size and %EE of optimized formulation were found to be 147.76 ± 2.14 nm and 69.18 ± 3.62%, respectively. Optimized PTH-LPs showed the sustained release profile of the drug. In vitro cell evaluation studies showed PTH-LPs have good biocompatibility with MG-63 cells. The cell proliferation study revealed that PTH-LPs induced osteoblast differentiation which improved the formation of mineralized nodules in MG-63 cells. The outcome of the present study conclusively demonstrated the potential of the QbD concept to build quality in PTH-LPs with improved osteoanabolic therapy in osteoporosis.

Pharmacological, Nutritional, and Rehabilitative Interventions to Improve the Complex Management of Osteoporosis in Patients with Chronic Obstructive Pulmonary Disease: A Narrative Review

Osteoporosis is a highly prevalent condition affecting a growing number of patients affected by chronic obstructive pulmonary disease (COPD), with crucial implications for risk of fragility fractures, hospitalization, and mortality. Several risk factors have been identified to have a role in osteoporosis development in COPD patients, including corticosteroid therapy, systemic inflammation, smoke, physical activity levels, malnutrition, and sarcopenia. In this scenario, a personalized multitarget intervention focusing on the pathological mechanisms underpinning osteoporosis is mandatory to improve bone health in these frail patients. Specifically, physical exercise, nutritional approach, dietary supplements, and smoke cessation are the cornerstone of the lifestyle approach to osteoporosis in COPD patients, improving not only bone health but also physical performance and balance. On the other hand, pharmacological treatment should be considered for both the prevention and treatment of osteoporosis in patients at higher risk of fragility fractures. Despite these considerations, several barriers still affect the integration of a personalized approach to managing osteoporosis in COPD patients. However, digital innovation solutions and telemedicine might have a role in optimizing sustainable networking between hospital assistance and community settings to improve bone health and reduce sanitary costs of the long-term management of COPD patients with osteoporosis.

GSK 650394 Inhibits Osteoclasts Differentiation and Prevents Bone Loss via Promoting the Activities of Antioxidant Enzymes In Vitro and In Vivo

Osteoporosis (OP) is one of the most common bone disorders among the elderly, characterized by abnormally elevated bone resorption caused by formation and activation of osteoblast (OC). Excessive reactive oxygen species (ROS) accumulation might contribute to the formation process of OC as an essential role. Although accumulated advanced treatment target on OP have been proposed in recent years, clinical outcomes remain unexcellence attributed to severe side effects. The purpose of present study was to explore the underlying mechanisms of GSK 650394 (GSK) on inhibiting formation and activation of OC and bone resorption in vitro and in vivo. GSK could inhibit receptor activator of nuclear-κB ligand (RANKL-)-mediated Oc formation via suppressing the activation of NF-κB and MAPK signaling pathways, regulating intracellular redox status, and downregulate the expression of nuclear factor of activated T cells c1 (NFATc1). In addition, quantitative RT-PCR results show that GSK could suppress the expression of OC marker gene and antioxidant enzyme genes. Consistent with in vitro cellular results, GSK treatment improved bone density in the mouse with ovariectomized-induced bone loss according to the results of CT parameters, HE staining, and Trap staining. Furthermore, GSK treatment could enhance the capacity of antioxidant enzymes in vivo. In conclusion, this study suggested that GSK could suppress the activation of osteoclasts and therefore maybe a potential therapeutic reagent for osteoclast activation-related osteoporosis.

Cellular Senescence in Bone

Senescence is an irreversible cell-cycle arrest process induced by environmental, genetic, and epigenetic factors. An accumulation of senescent cells in bone results in age-related disorders, and one of the common problems is osteoporosis. Deciphering the basic mechanisms contributing to the chronic ailments of aging may uncover new avenues for targeted treatment. This review focuses on the mechanisms and the most relevant research advancements in skeletal cellular senescence. To identify new options for the treatment or prevention of age-related chronic diseases, researchers have targeted hallmarks of aging, including telomere attrition, genomic instability, cellular senescence, and epigenetic alterations. First, this chapter provides an overview of the fundamentals of bone tissue, the causes of skeletal involution, and the role of cellular senescence in bone and bone diseases such as osteoporosis. Next, this review will discuss the utilization of pharmacological interventions in aging tissues and, more specifically, highlight the role of senescent cells to identify the most effective and safe strategies.

Treatment of postmenopausal osteoporosis patients with teriparatide for 24 months reverts forming bone quality indices to premenopausal healthy control values

Postmenopausal osteoporosis (PMOP) therapies are frequently evaluated by bone mineral density (BMD) gains against patients receiving placebo (calcium and vitamin D supplementation, a mild bone turnover-suppressing intervention), which is not equivalent to either healthy or treatment-naive PMOP. The aim of the present observational study was to assess the effects of TPTD treatment in PMOP (20 μg, once daily) at 6 (TPTD 6m; n = 28, age 65 ± 7.3 years), and 24 (TPTD 24m; n = 32, age 67.4 ± 6.15 years) months on bone quality indices at actively forming trabecular surfaces (with fluorescent double labels). Data from the TPTD-treated PMOP patients were compared with those in healthy adult premenopausal women (HC; n = 62, age 40.5 ± 10.6 years), and PMOP receiving placebo (PMOP-PLC; n = 94, age 70.6 ± 4.5 years). Iliac crest biopsies were analyzed by Raman microspectroscopy at three distinct tissue ages: mid-distance between the second label and the bone surface, mid-distance between the two labels, and 1 μm behind the first label. Mineral to matrix ratio (MM), mineral maturity/crystallinity (MMC), tissue water (TW), glycosaminoglycan (GAGs), and pyridinoline (Pyd) content were determined. Outcomes were compared by ANCOVA with subject age and tissue age as covariates, and health status as a fixed factor, followed by Sidak's post-hoc testing (significance assigned to p < 0.05). Both TPTD groups increased MM compared to PMOP-PLC. While TPTD 6m had values similar to HC, TPTD 24m had higher values compared to either HC or TPTD 6m. Both TPTD groups had lower MMC values compared to PMOP-PLC and similar to HC. TPTD 6m patients had higher TW content compared to HC, while TPTD 24m had values similar to HC and lower than either PMOP-PLC or TPTD 6m. Both TPTD groups had lower GAG content compared to HC group, while TPTD 6m had higher values compared to PMOP-PLC. Finally, TPTD 6m patients had higher Pyd content compared to HC and lower compared to PMOP-PLC, while TPTD 24m had lower values compared to PMOP-PLC and TPTD 6m, and similar to HC group. The results of the present study indicate that effects of TPTD on forming trabecular bone quality indices depend on treatment duration. At the recommended length of 24 m, TPTD restores bone mineral and organic matrix quality indices (MMC, TW, Pyd content) to premenopausal healthy (HC) levels.

Elevation of transaminases associated with teriparatide treatment: a case report

This report describes the case of a 64-year-old Caucasian woman presenting with hypertransaminasemia during treatment with teriparatide for postmenopausal osteoporosis. The patient was also receiving food supplements containing red yeast rice (RYR) to lower her cholesterol levels. RYR has been reported to cause hepatoxicity because it contains monacolin K. According to the results of a causality assessment, carried out via several probability scales, teriparatide was defined as a 'possible' cause of the adverse drug reaction (ADR). Following progressive normalisation of the levels of transaminases after the teriparatide was discontinued, we therefore postulated that teriparatide was the main cause of the ADR. In addition to this, based on a literature review, we considered RYR as a concomitant agent in the aetiology of the ADR. Further post-marketing surveillance studies on teriparatide seem to be necessary.

Antiosteoporosis effect of tanshinol in osteoporosis animal models: A systematic review and meta-analysis

Background: Osteoporosis (OP) is an age-related bone disease that has emerged as a worldwide public health concern due to its increasing incidence and high disability rate. Tanshinol [D (+) β-3,4-dihydroxyphenyl lactic acid, TS], a water-soluble component extracted from Salvia miltiorrhiza, has proven to be effective in attenuating OP in vitro and in vivo. However, there is insufficient evidence to support its clinical application.

Objective: This meta-analysis aimed to investigate available OP animal model studies to demonstrate the antiosteoporosis effects of TS in a systematic manner.

Methods: Electronic searches of related studies were conducted in the following databases: EMBASE, PubMed, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure, Chinese VIP Database, Chinese Biomedical Literature Database, and Wanfang. The retrieval date was January 2022, and there were no time or language restrictions. The CAMARADES 10-item quality checklist was utilized to test the risk of potential bias for each study, and modifications were performed accordingly. The primary outcome was bone mineral density (BMD, which included the femur and lumbar spine); and secondary outcomes were parameters for trabecular bone such as bone volume over total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), conditions of the femur (including bone maximum load and bone elastic load), and markers of bone metabolism (serum osteocalcin, S-OCN).

Results: A total of nine studies including 176 rats were chosen for this analysis. Egger’s test revealed the presence of publication bias in various studies regarding the primary outcome. According to this systematic review, TS significantly increased the BMD of the femur (BMD-femur) (SMD = 4.40; 95% CI = 1.61 to 7.19; p = 0.002, I² = 94.6%), BMD of the lumbar spine (BMD-lumbar) (SMD = 6.390; 95% CI = 2.036 to 10.744; p = 0.004, I² = 95.9%), BV/TV (SMD = 0.790; 95% CI = 0.376 to 1.204; p = 0.000, I² = 10.8), Tb.N (SMD = 0.690; 95% CI = 0.309 to 1.071; p = 0.000, I² = 12%), Tb.Th (SMD = 0.772; 95% CI = 0.410 to 1.134; p = 0.000, I² = 32.2%), and S-OCN (SMD = 3.13; 95% CI = 0.617 to 5.65; p = 0.015, I² = 92.3%), while the Tb.Sp level was markedly decreased in OP models in comparison to the controls (SMD = −0.822; 95% CI = −1.207 to −0.437; p = 0.000, I² = 0%). Moreover, TS treatment was associated with a significant improvement of the bone biomechanical indicators, including bone maximum load (SMD = 0.912; 95% CI = 0.370 to 1.455; p = 0.001, I² = 40%) and elasticity load (SMD = 0.821; 95% CI = 0.290 to 1.351; p = 0.002, I² = 0%).

Conclusion: Collectively, our findings suggest that TS can improve BMD, bone microarchitecture, bone biomechanics, and S-OCN expression in rats, implying that it could be used clinically in the future.

Systematic Review Registration:https://inplasy.com/inplasy-2022-3-0053/, identifier [INPLASY202230053].

Teriparatide and osteosarcoma risk: history, science, elimination of boxed warning, and other label updates

The phase 3 trials of the bone anabolic drug teriparatide were prematurely terminated because of a preclinical finding of osteosarcoma in rats treated with high doses of teriparatide for near lifetime. Even so, results from these and subsequent clinical trials showed efficacy and tolerability. Based on the phase 3 results and additional preclinical investigations, Forteo (teriparatide) was approved for use in the United States with an indication for the treatment of osteoporosis in patients at high risk for fracture, a boxed warning regarding potential risk of osteosarcoma, a 2‐year lifetime limitation of use, other risk mitigations, and a requirement to assess for risk of osteosarcoma in humans treated with teriparatide. Subsequent investigations included five real‐world studies directed at assessing a connection between teriparatide and osteosarcoma risk in humans. The early studies did not identify an increased risk of osteosarcoma but were inadequate to sufficiently characterize risk, given the low incidence of this rare form of bone cancer. Learning from these efforts, two studies were undertaken using claims data to identify large cohorts of patients treated with teriparatide and assess whether these patients were found to have osteosarcoma by linking pharmacy claims data with data from cancer registries. These studies showed no increase in osteosarcoma in patients using teriparatide compared with unexposed groups, as well as to the expected population‐based background incidence of the disease. Based on this real‐world evidence and the totality of data collected from postmarketing use and other clinical investigations, the label was updated in 2020. The changes included addition of information from large observational studies using real‐world evidence, removal of the boxed warning, and a revision of the 2‐year lifetime limitation. Thus, observational studies with large sample sizes using real‐world data can provide supportive evidence to facilitate regulatory decisions including the elimination of a boxed warning. © 2022 Eli Lilly and Company. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Repurposed and investigational disease-modifying drugs in osteoarthritis (DMOADs)

In spite of a major public health burden with increasing prevalence, current osteoarthritis (OA) management is largely palliative with an unmet need for effective treatment. Both industry and academic researchers have invested a vast amount of time and financial expense to discover the first diseasing-modifying osteoarthritis drugs (DMOADs), with no regulatory success so far. In this narrative review, we discuss repurposed drugs as well as investigational agents which have progressed into phase II and III clinical trials based on three principal endotypes: bone-driven, synovitis-driven and cartilage-driven. Then, we will briefly describe the recent failures and lessons learned, promising findings from predefined post hoc analyses and insights gained, novel methodologies to enhance future success and steps underway to overcome regulatory hurdles.

Effect of Teriparatide on Bone Mineral Density and Trabecular Bone Score in Type 2 Diabetic Patients with Osteoporosis: A Retrospective Cohort Study

The BMDs of the lumbar spine, whole femur, and femoral neck and TBS were measured. Change in BMD or TBS was defined as the BMD or TBS at follow-up, performed 1 year after baseline, minus baseline BMD or TBS. Results: This retrospective cohort study included 93 patients, of whom 52 received no medication, 26 received bisphosphonates, and 15 received weekly teriparatide. BMD of the lumbar spine increased in all three groups. There was no change in BMD of the whole femur and femoral neck in the no medication and bisphosphonates groups, whereas the BMD of the whole femur (from 0.73 (0.15) to 0.74 (0.15) g/cm², p = 0.011) and femoral neck (from 0.59 (0.16) to 0.60 (0.16) g/cm², p = 0.011) in the teriparatide group increased. The change in BMD of the femoral neck (no medication; −0.002 (0.034) g/cm², bisphosphonates; −0.0001 (0.024) g/cm², and teriparatide; 0.017 (0.022) g/cm², p = 0.091) or TBS (no medication; −0.007 (0.051), bisphosphonates; −0.058 (0.258), and teriparatide; 0.021 (0.044), p = 0.191) in the teriparatide group tended to be higher than that in the other groups, although there was no statistically significant difference. Conclusions: Teriparatide increased the BMD of the femoral neck and TBS in osteoporosis patients with type 2 diabetes mellitus, compared to bisphosphonates and no medication.

Solution design to extend the pH range of the pH-responsive precipitation of a CspB fusion protein

Cell surface protein B (CspB) from Corynebacterium glutamicum has been developed as a reversible pH-responsive tag for protein purification. CspB fusion proteins precipitate at acidic pH, after that they completely dissolve at neutral pH. This property has been used in a non-chromatographic protein purification method named pH-responsive Precipitation-Redissolution of CspB tag Purification (pPRCP). However, it is difficult to apply pPRCP to proteins that are unstable under acidic conditions. In an effort to shift the precipitation pH to a milder range, we investigated the solution conditions of CspB-fused Teriparatide (CspB50TEV-Teriparatide) during the process of pH-responsive precipitation using pPRCP. The purified CspB50TEV-Teriparatide in buffer without additives precipitated at pH 5.3. By contrast, CspB50TEV-Teriparatide in buffer with 0.5 M Na₂SO₄ precipitated at pH 6.6 because of the kosmotropic effect. Interestingly, the pH at which precipitation occurred was independent of the protein concentration. The precipitated CspB50TEV-Teriparatide was fully redissolved at above pH 8.0 in the presence or absence of salt. The discovery that proteins can be precipitated at a mild pH will allow pPRCP to be applied to acid-sensitive proteins.

Advances in pathogenesis and therapeutic strategies for osteoporosis

Osteoporosis, is the most common bone disorder worldwide characterized by low bone mineral density, leaving affected bones vulnerable to fracture. Bone homeostasis depends on the precise balance between bone resorption by osteoclasts and bone matrix formation by mesenchymal lineage osteoblasts, and involves a series of complex and highly regulated steps. Bone homeostasis will be disrupted when the speed of bone resorption is faster than bone formation. Based on various regulatory mechanisms of bone homeostasis, a series of drugs targeting osteoporosis have emerged in clinical practice, including bisphosphonates, selective estrogen receptor modulators, calcitonin, molecular-targeted drugs and so on. However, many drugs have major adverse effects or are unsuitable for long-term use. Therefore, it is very urgent to find more effective therapeutic drugs based on the new pathogenesis of osteoporosis. In this review, we summarize novel mechanisms involved in the pathological process of osteoporosis, including the roles of gut microbiome, autophagy, iron balance and cellular senescence. Based on the above pathological mechanism, we found promising drugs for osteoporosis treatment, such as: probiotics, alpha-ketoglutarate, senolytics and hydrogen sulfide. This new finding may provide an important basis for elucidating the complex pathological mechanisms of osteoporosis and provide promising drugs for clinical osteoporosis treatment.

Effects of local single dose administration of parathormone on the early stages of osseointegration: A pre-clinical study

The present study aimed to evaluate the effect of parathormone (PTH) administered directly to the implant's surface prior to insertion, using a large translational animal model. Sixty titanium implants were divided into four groups: (i) Collagen, control group, where implants were coated with Type-I Bovine-collagen, and three experimental groups, where implants received varying doses of PTH: (ii) 12.5, (iii) 25, and (iv) 50 μg, prior to placement. Fifteen female sheep (~2 years old, weighing ~65 kg) received four implants in an interpolated fashion in C3, C4 or C5 vertebral bodies. After 3-, 6- and 12-weeks, samples were harvested, histologically processed, qualitatively and quantitatively assessed for bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). BIC yielded lower values at 6-weeks for 50 μg relative to the control group, with no significant differences, when compared to the 12.5- and 25-μg. No significant differences were detected at 6-weeks between collagen, 12.5- and 25-μg groups. At 3- and 12-weeks, no differences were detected for BIC among PTH groups. With respect to BAFO, no significant differences were observed between the control and experimental groups independent of PTH concentration and time in vivo. Qualitative observations at 3-weeks indicated the presence of a more mature bone near the implant's surface with the application of PTH, however, no significant differences in new bone formation or healing patterns were observed at 6- and 12-weeks. Single local application of different concentrations of PTH on titanium implant's surface did not influence the osseointegration at any time-point evaluation in low-density bone.

Cost-Effectiveness of Sequential Teriparatide/Zoledronic Acid Compared With Zoledronic Acid Monotherapy for Postmenopausal Osteoporotic Women in China

Objective

We aimed to assess the cost-effectiveness of sequential teriparatide/zoledronic acid relative to zoledronic acid monotherapy for postmenopausal osteoporotic women in China.

Methods

A previously validated Markov microsimulation model was updated to examine the cost-effectiveness of daily subcutaneous teriparatide for 2 years followed by annual intravenous zoledronic acid for 3 years (sequential teriparatide/zoledronic acid), compared with zoledronic acid monotherapy for 3 years in Chinese women with postmenopausal osteoporosis at ages 65, 70, 75, and 80 from the health care payer perspective.

Results

The incremental cost-effectiveness ratios (ICERs) (US dollars [$] per quality-adjusted life-year [QALY]) of sequential teriparatide/zoledronic acid vs. zoledronic acid monotherapy was $173,223/QALY at age 65 years, which was much higher than the pre-determined willingness-to-pay (WTP) threshold of $ 31,512/QALY, and the results were similar at other ages. In one-way sensitivity analyses, the two most impactful parameters were the cost of teriparatide and the residual effects of the medications included in this study. Sequential teriparatide/zoledronic acid became cost-effective at age 80 with the cost of teriparatide reduced by 50%. Without the residual effect, the ICER increased to $257,982/QALY. Probabilistic sensitivity analyses shown that the probabilities of zoledronic acid monotherapy being cost-effective were 100% at a WTP of $31,512/QALY.

Conclusions

Among Chinese women with postmenopausal osteoporosis, sequential teriparatide/zoledronic acid was not cost-effective unless the cost of teriparatide was reduced by 50% only for the participants over 80 years.

Case Report: Everolimus reduced bone turnover markers but showed no clinical benefit in a patient with severe progressive osseous heteroplasia

BACKGROUND

Progressive osseous heteroplasia (POH) is an ultrarare genetic disorder characterized by an inactivating mutation in the GNAS gene that causes heterotopic ossification. Inhibition of the mammalian target of the rapamycin (mTOR) signalling pathway has been proposed as a therapy for progressive bone fibrodysplasia and non-genetic forms of bone heteroplasia. Herein, we describe the impact of using Everolimus as a rescue therapy for an identical twin girl exhibiting an aggressive clinical phenotype of POH.

METHODS

Clinical evaluation of the progression of the disease during Everolimus treatment was performed periodically. Cytokine markers involved in bone metabolism and protein markers related to bone activity were analyzed to explore bone turnover activity.

RESULTS

The patient received Everolimus therapy for 36 weeks. During treatment, no clinical improvement of the disease was perceived. Analysis of biochemical parameters, namely, β-CTX (r ² = -0.576, P-value = 0.016) and PNIP (r ² = -0.598, P-value = 0.011), indicated that bone turnover activity was significantly reduced. Additionally, bone metabolism-related biomarkers showed only a significant positive correlation with PTH levels.

CONCLUSIONS

Everolimus treatment did not modify the clinical progression of the disease in an aggressive form of POH, although an impact on the protein markers studied was observed.

The Effect of Teriparatide Treatment on the Risk of Fragility Fractures in Postmenopausal Women with Osteoporosis: Results from the Asian and Latin America Fracture Observational Study (ALAFOS)

The Asian and Latin America Fracture Observational Study (ALAFOS) is a prospective, observational, single-arm study conducted in 20 countries across Asia, Latin America and the Middle East. ALAFOS evaluated new clinical vertebral and non-vertebral fragility fractures in relation to time on teriparatide, in postmenopausal women with osteoporosis in real-life clinical practice. Clinical fragility fractures, back pain, and health-related quality of life (HRQoL) were recorded in 6-month intervals for ≤ 24 months during teriparatide treatment and up to 12-months post-treatment. Data were analysed with piecewise exponential regression with inverse probability weighting for time to event outcomes and mixed-model repeated measures for back pain and HRQoL. 3054 postmenopausal women started teriparatide and attended ≥ one follow-up visit (mean [SD] age 72.5 [10.4] years). The median (95% CI) time to treatment discontinuation was 22.0 months (21.2, 22.8). During the treatment period, 111 patients (3.6%) sustained 126 clinical fractures (2.98 fractures/100 patient-years). Rates of new clinical fragility fractures were significantly decreased during the > 6-12, > 12-18, and > 18-24-month periods, as compared with the first 6 months of treatment (hazard ratio [HR] 0.57; 95% CI 0.37, 0.88; p = 0.012; HR 0.35; 95% CI 0.19, 0.62; p < 0.001; HR 0.43; 95% CI 0.23, 0.83; p = 0.011; respectively). Patients also reported an improvement in back pain and HRQoL (p < 0.001). These results provide data on the real-world effectiveness of teriparatide in the ALAFOS regions and are consistent with other studies showing reduction of fractures after 6 months of teriparatide treatment. These results should be interpreted in the context of the noncontrolled design of this observational study.

The Effect of Daily Teriparatide versus One-Time Annually Zoledronic Acid Administration After Transforaminal Lumbar Interbody Fusion in Osteoporotic Patients

Purpose

The research aimed to compare the therapeutic effect of teriparatide (TPTD) and zoledronic acid (ZOL) therapy on bone formation and spinal fusion in patients with osteoporosis (OP) who underwent transforaminal lumbar interbody fusion (TLIF).

Methods

On the basis of different anti-OP treatment options, the TPTD group was treated daily with TPTD (20 μg. ih. qd) for at least 6 months, while the ZOL group was treated with a single dose of ZOL (5 mg. ivgtt. st) postoperatively. The visual analogue scale (VAS), Oswestry Disability Index (ODI), bone mineral density (BMD), and concentration of bone turnover markers before, 6, and 12 months after surgery were evaluated. X-ray and three-dimensional computed tomography scans were performed at 6 and 12 months postoperatively to assess interbody fusion.

Results

The number of patients in the TPTD and ZOL groups was 29 and 38 patients, respectively. The VAS and ODI scores in both groups were significantly reduced at 6 and 12 months after TLIF. Compared with that of baseline, the lumbar spine BMD of TPTD patients increased significantly from 0.716±0.137 g/cm² to 0.745±0.124 g/cm² and 0.795±0.123 g/cm² at 6 and 12 months, respectively, and was significantly higher than that of the ZOL group at 12 months (0.720±0.128 g/cm²). The bone formation marker, P1NP, in the TPTD group increased significantly (145.48±66.64 ng/mL and 119.55±88.27 ng/mL) compared with baseline (44.67±25.15 ng/mL) and in the ZOL group (28.82±19.76 ng/mL and 29.94±20.67 ng/mL) at 6 and 12 months, respectively. The fusion rates in the TPTD and ZOL groups were 57% and 45% at 6 months, without statistical significance. However, TPTD had a more statistically significant positive influence on fusion rate than ZOL at 12 months (86% vs 70%).

Conclusion

TPTD was more efficient than ZOL in bone formation and spinal fusion in OP patients who underwent TLIF.

Which injected antiosteoporotic medication is worth paying for? A cost-effectiveness analysis of teriparatide, zoledronate, ibandronate, and denosumab for postmenopausal osteoporotic women in China

OBJECTIVE

The purpose of this study was to evaluate the cost-effectiveness of four injected antiosteoporotic medications including teriparatide, zoledronate, ibandronate, and denosumab for postmenopausal osteoporotic women in China.

METHODS

A Markov microsimulation model was used to compare the cost-effectiveness of the four drugs above in Chinese postmenopausal osteoporotic women with no fracture history of hip, vertebral, or wrist at various ages (65, 70, 75, and 80) of therapy initiation from the health care payer perspective.

RESULTS

Denosumab was dominant (ie, lower costs and greater quality-adjusted life-years [QALYs]) compared with other strategies at all ages studied. The incremental cost-effectiveness ratios (ICERs) of zoledronate or ibandronate versus no treatment were $4,482.88/ QALYs or $11,378/QALYs, respectively, at age 65 years, and the results at other ages were similar. In contrast, the incremental cost-effectiveness ratio of teriparatide strategy compared with no treatment exceeded the pre-determined threshold of a willingness-to-pay of $31,512/QALY regardless of the adoption of the patient assistance program at all ages studied, and a threshold analysis showed that teriparatide without patient assistance program became cost-effective when the annual drug cost is decreased to $1,644.87 (current cost: $8,764.65). The cost-effectiveness decision did not change in most of the one-way sensitivity analyses. A scenario analysis considering no offset effect of denosumab showed that zoledronate had the potential to become the optimal option relative to denosumab. In probabilistic sensitivity analyses, the probabilities of denosumab being cost-effective compared with other strategies were 100% at a willingness-to-pay of $31,512/QALY.

CONCLUSIONS

Among postmenopausal osteoporotic women in China, denosumab therapy is cost-effective at all ages examined from the health care payer perspective, compared with teriparatide, zoledronate, or ibandronate. This study will help clinicians and policymakers make better decisions about the relative economic value of osteoporosis treatments in China.

Single Dose of SHR-1222, a Sclerostin Monoclonal Antibody, in Healthy Men and Postmenopausal Women With Low Bone Mass: A Randomized, Double-Blind, Placebo-Controlled, Dose-Escalation, Phase I Study

SHR-1222 is a humanized monoclonal antibody targeting sclerostin and has the potential to promote bone formation and reduce bone resorption. This study was aimed to assess the safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity of SHR-1222 in healthy men and postmenopausal women with low bone mass (BMD). It was a randomized, double-blind, placebo-controlled, dose-escalation, phase I study. Subjects received SHR-1222 at 50, 100, 200, 300, and 400 mg sequentially or matching placebo subcutaneously. Totally, 50 subjects with low BMD were enrolled and randomly assigned; 10 received placebo and 40 received SHR-1222 (50 mg, n = 4; 100, 200, 300, or 400 mg, n = 9). The most common adverse events that occurred at least 10% higher in subjects with SHR-1222 treatment than those with placebo were decreased blood calcium, blood urine present, increased blood cholesterol, electrocardiogram T wave abnormal, urinary tract infection, increased blood pressure diastolic, and positive bacterial test. All the above adverse events were mild in severity and well resolved except one of increased blood cholesterol in a subject lost to follow-up. The serum SHR-1222 concentration increased in a dose-dependent manner. Administration of SHR-1222 upregulated the bone-formation markers N-terminal propeptide of type 1 procollagen, osteocalcin, and bone-specific alkaline phosphatase, while downregulated the bone-resorption marker β-C-telopeptide. The BMD at the lumbar spine notably rose after a single dose of SHR-1222. The largest increase occurred in the 400 mg cohort (3.8, 6.7, and 6.1% on day 29, 57, and 85, respectively; compared with 1.4, 0.8, and 1.0% in the placebo group). Although 10.0% of subjects receiving SHR-1222 tested positive for anti–SHR-1222 antibodies, no obvious effects of antibody formation were found on pharmacokinetics. Overall, SHR-1222 was well tolerated at doses from 50 to 400 mg and is a promising new remedy for osteoporosis.

Clinical Trial Registration:http://www.clinicaltrials.gov, NCT03870100.

Mesenchymal stem cells plus bone repair materials as a therapeutic strategy for abnormal bone metabolism: Evidence of clinical efficacy and mechanisms of action implied

The regeneration process of human bones is very complicated, the management and treatment of bone damage caused by diseases are the main problems faced by clinicians worldwide. It is known that cell-based stem cell therapy together with biomaterials is a fast-developing method of tissue regeneration. This review focuses on the different types and main characteristics of scaffolds and stem cells suitable for bone regeneration, and aims to provide a state-of-the-art description of the current treatment of common bone metabolism related diseases such as osteoarthritis, osteoporosis and osteosarcoma and the strategies based on stem cell biological scaffolds used in bone tissue engineering. This method may provide a new treatment option for the treatment of common bone metabolism-related diseases that cannot be cured by ordinary and routine applications. Three databases (PubMed, CNKI and Web of Science) search terms used to write this review are: "arthritis", "osteoporosis", "osteosarcoma", "bone tissue engineering", "mesenchymal stem cells", "materials", "bioactive scaffolds" and their combinations, and the most relevant studies are selected. As a conclusion, it needs to be emphasized that despite the encouraging results, further development is needed due to the need for more in-depth research, standardization of stem cell manufacturing processes, large-scale development of clinical methods for bone tissue engineering, and market regulatory approval. Although the research and application of tissue regeneration technology and stem cells are still in their infancy, the application prospect is broad and it is expected to solve the current clinical problems.

The pathophysiology of immunoporosis: innovative therapeutic targets

BACKGROUND

The physiological balance between bone resorption and bone formation is now known to be mediated by a cascade of events parallel to the classic osteoblast-osteoclast interaction. Thus, osteoimmunology now encompasses the role played by other cell types, such as cytokines, lymphocytes and chemokines, in immunological responses and how they help modulate bone metabolism. All these factors have an impact on the RANK/RANKL/OPG pathway, which is the major pathway for the maturation and resorption activity of osteoclast precursor cells, responsible for osteoporosis development. Recently, immunoporosis has emerged as a new research area in osteoimmunology dedicated to the immune system's role in osteoporosis.

METHODS

The first part of this review presents theoretical concepts on the factors involved in the skeletal system and osteoimmunology. Secondly, existing treatments and novel therapeutic approaches to treat osteoporosis are summarized. These were selected from to the most recent studies published on PubMed containing the term osteoporosis. All data relate to the results of in vitro and in vivo studies on the osteoimmunological system of humans, mice and rats.

FINDINGS

Treatments for osteoporosis can be classified into two categories. They either target osteoclastogenesis inhibition (denosumab, bisphosphonates), or they aim to restore the number and function of osteoblasts (romozumab, abaloparatide). Even novel therapies, such as resolvins, gene therapy, and mesenchymal stem cell transplantation, fall within this classification system.

CONCLUSION

This review presents alternative pathways in the pathophysiology of osteoporosis, along with some recent therapeutic breakthroughs to restore bone homeostasis.

A Novel HR-pQCT Image Registration Approach Reveals Sex-Specific Changes in Cortical Bone Retraction With Aging

During aging, changes in endosteal and periosteal boundaries of cortical bone occur that differ between men and women. We here develop a new procedure that uses high-resolution peripheral quantitative CT (HR-pQCT) imaging and 3D registration to identify such changes within the timescale of longitudinal studies. A first goal was to test the sensitivity of the approach. A second goal was to assess differences in periosteal/endosteal expansion over time between men and women. Rigid 3D registration was used to transform baseline and all follow-up (FU) images to a common reference configuration for which the region consisting of complete slices (largest common height) was determined. Periosteal and endosteal contours were transformed to the reference position to determine the net periosteal and endosteal expansion distances. To test the sensitivity, images from a short-term reproducibility study were used (15 female, aged 21 to 47 years, scanned three times). To test differences between men and women, images from a subset of the Geneva Retirees Cohort were used (248 female, 61 male, average age 65 years, 3.5 and 7 years FU). The sensitivity study indicated a least significant change for detecting periosteal/endosteal expansion of 41/31 microns for the radius and 17/26 microns for the tibia. Results of the cohort study showed significant net endosteal retraction only in females at the radius and tibia after 3.5 years (38.0 and 38.4 microns, respectively) that further increased at 7 years FU (70.4 and 70.8 microns, respectively). No significant net periosteal changes were found for males or females at 7 years. The results demonstrate that it is possible to measure changes in endosteal contours in longitudinal studies within several years. For the investigated cohort, significant endosteal retraction was found in females but not in males. Whether these changes in cortical geometry are related to fracture risk remains to be investigated in larger cohorts © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

COVID-19 and the Endocrine System: A Comprehensive Review on the Theme

Background and aim. The review aimed to summarize advances in the topic of endocrine diseases and coronavirus disease 2019 (COVID-19). Methods. Scientific and institutional websites and databases were searched and data were collected and organized, when plausible, to angle the discussion toward the following clinical issues. (1) Are patients with COVID-19 at higher risk of developing acute or late-onset endocrine diseases or dysfunction? (2) May the underlying endocrine diseases or dysfunctions be considered risk factors for poor prognosis once the infection has occurred? (3) Are there defined strategies to manage endocrine diseases despite pandemic-related constraints? Herein, the authors considered only relevant and more frequently observed endocrine diseases and disorders related to the hypothalamic-pituitary region, thyroid and parathyroid glands, calcium-phosphorus homeostasis and osteoporosis, adrenal glands, and gonads. Main. Data highlight the basis of some pathophysiological mechanisms and anatomical alterations of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)-induced endocrine dysfunctions. Some conditions, such as adrenal insufficiency and cortisol excess, may be risk factors of worse clinical progression once the infection has occurred. These at-risk populations may require adequate education to avoid the SARS-CoV-2 infection and adequately manage medical therapy during the pandemic, even in emergencies. Endocrine disease management underwent a palpable restraint, especially procedures requiring obligate access to healthcare facilities for diagnostic and therapeutic purposes. Strategies of clinical triage to prioritize medical consultations, laboratory, instrumental evaluations, and digital telehealth solutions should be implemented to better deal with this probably long-term situation.

Effects of Teriparatide versus Salmon Calcitonin Therapy for the Treatment of Osteoporosis in Asia: A Meta-analysis of Randomized Controlled Trials

Objective:

The objective of this meta-analysis was to compare the efficacy and safety of teriparatide versus salmon calcitonin for the treatment of osteoporosis in Asian patients and to investigate whether the results of global studies could be applicable to Asian patients.

Methods:

PubMed, OVID, Cochrane Central Register of Controlled Trials (CENTRAL) and EMBASE up to December 2018 were searched. Eligible randomized controlled trials (RCTs) that compared teriparatide versus salmon calcitonin in Asian osteoporosis population were included. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for data synthesis, and Cochrane Collaboration software Review Manager 5.3 was used to analyze the pooled data.

Results:

Three RCTs involving 529 patients were included (mean age 68.7 yr; 93.4% females; mean follow-up 6 months); outcome measures included bone mineral density (BMD) of the femoral neck, total hip and lumbar spine; bone markers and adverse events. We found that the period of 6-months of teriparatide treatment was helpful for the improvement of the BMD of lumbar vertebra, however, the improvement of BMD was not significant in the femoral neck and total hip joint. There was a positive correlation between bone-specific alkaline phosphatase (BSAP) and osteocalcin (OCN) and the response of Asian patients to subcutaneous injection of 20 micrograms per day of teriparatide. The proportion of the occurrence of adverse effects was more obvious in the teriparatide group compared with salmon calcitonin, but there was no significant difference.

Conclusion:

Results suggested that the use of teriparatide could improve the lumbar BMD by shortterm (six months) application in Asian osteoporosis patients, which is beneficial to the patients who cannot tolerate adverse events of long-term treatment. The BSAP and OCN bone markers could be useful to monitor the responses of Asian osteoporosis patients to teriparatide treatment. Finally, both of teriparatide and salmon calcitonin were well tolerated by Asian patients.

A novel RANKL-targeted flavonoid glycoside prevents osteoporosis through inhibiting NFATc1 and reactive oxygen species

BACKGROUND AND PURPOSE

Osteoporosis is characterized by excessive bone resorption due to enhanced osteoclast activation. Stimulation of nuclear factor of activated T cells 1 (NFATc1) and accumulation of reactive oxygen species (ROS) are important mechanisms underlying osteoclastogenesis. Robinin (Rob) is a flavonoid glycoside that has shown anti-inflammatory and antioxidative effects in previous studies, but little is known about its effects on bone homeostasis. The purpose of our research was to investigate whether Rob could prevent bone resorption in ovariectomized (OVX) mice by suppressing osteoclast production through its underlying mechanisms.

METHODS

The docking pose of Rob and RANKL was identified by protein-ligand molecular docking. Rob was added to bone marrow macrophages (BMMs) stimulated by nuclear factor-κB (NF-κB) ligand (RANKL). The effects of Rob on osteoclastic activity were evaluated by positive tartrate resistant acid phosphatase (TRAcP) staining kit and hydroxyapatite resorption assay. RANKL-induced ROS generation in osteoclasts was detected by H2 DCFDA and MitoSox Red staining. The classic molecular cascades triggered by RANKL, such as NF-κB, ROS, calcium oscillations, and NFATc1-mediated signaling pathways, were investigated using Fluo4 staining, western blot, and quantitative real-time polymerase chain reaction. In addition, an OVX mouse model mimicking estrogen-deficient osteoporosis was created to evaluate the therapeutic effects of Rob in vivo.

RESULTS

Computational docking results showed that Rob could bind specifically to RANKL's predicted binding sites. In vitro, Rob inhibited RANKL-mediated osteoclastogenesis dose-dependently without obvious cytotoxicity at low concentrations. We also found that Rob attenuated RANKL-induced mitochondrial ROS production or enhanced activities of ROS-scavenging enzymes, and ultimately reduced intracellular ROS levels. Rob abrogated the RANKL-induced mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways, and subsequently blocked NFATc1 signaling and TRAcP expression. In addition, Rob inhibited osteoclast proliferation by downregulating the expression of osteoclast target genes (Acp5, Cathepsin K, Atp6v0d2, Nfact1, c-Fos, and Mmp9) and reducing Ca2+ oscillations. Our in vivo results showed that Rob reduced bone resorption in OVX animal model by repressing osteoclast activity and function.

CONCLUSIONS

Rob inhibits the activation of osteoclasts by targeting RANKL and is therefore a potential osteoporosis drug.