Long-term use of bisphosphonates in osteoporosis

A brief review and clinical evidences of teriparatide therapy for atypical femoral fractures associated with long-term bisphosphonate treatment

The risk of bisphosphonate (BP)-associated atypical femur fracture (AFF) has markedly increased over recent decades due to suppression of bone turnover, accumulation of structural micro-damage and reduction of bone remodeling consequent to long-term BP treatment. These medications further delay bone union and result in challenging clinical management. Teriparatide (TPTD), a synthetic human parathyroid hormone, exhibits unique anabolic effects and can increase bone remodeling and improve bone microarchitecture, further promoting fracture healing and reducing the rate of bone non-union. In this study, we briefly define AFF as well as the effects of BPs on AFFs, detailed the role of TPTD in AFF management and the latest clinical therapeutic findings. We have confirmed that TPTD positively promotes the healing of AFFs by reducing the time to bone union and likelihood of non-union. Thus, teriparatide therapy could be considered as an alternative treatment for AFFs, however, further research is required for the establishment of effective clinical guidelines of TPTD use in the management of AFF.

Alendronate treatment in cats with persistent ionized hypercalcemia: A retrospective cohort study of 20 cases

BACKGROUND

Limited information is available concerning treatment of ionized hypercalcemia in cats.

HYPOTHESIS/OBJECTIVES

Describe clinical findings in a cohort of cats with persistent ionized hypercalcemia and evaluate long-term tolerance and efficacy of alendronate in these patients.

ANIMALS

Twenty cats with persistent ionized hypercalcemia of undetermined origin, presented for routine or referral consultation at the teaching hospital of Maisons-Alfort (France).

METHODS

Medical records were retrospectively reviewed. Cats were divided into Group 1 (cats that received alendronate as well as other treatments, n = 11) and Group 2 (cats that did not receive alendronate, n = 9). Survival analysis (Kaplan-Meier method, log-rank test, and Cox proportional hazard models) was conducted to compare time to selected outcomes.

RESULTS

Azotemia was present in 15 cats (75%). Alendronate treatment was administered and well tolerated during the entire follow-up period (median, 9.5 months; interquartile range [IQR], 6.3; 27) in all cats from Group 1, except in 1 cat that developed severe hypophosphatemia, prompting treatment discontinuation. Univariate analysis determined that alendronate treatment was significantly associated with shorter time to reach a 15% decrease in ionized calcium concentration (iCa) from baseline during follow-up (119 days vs median not reached, P = .02). This association was no longer significant after adjustment for age and initial iCa.

CONCLUSIONS AND CLINICAL IMPORTANCE

Alendronate overall was well tolerated with chronic use in this cohort, and can be considered a treatment option for persistent ionized hypercalcemia in cats.

Mechanism of Huangqi Sanxian Decoction Inhibiting Osteoclast Differentiation Based on Network Pharmacology

Osteoclasts (OCs) have been the unique cell type exhibiting the bone-resorption activity in body. It is important to identify drugs to resist osteoclastogenesis to manage the bone-loss disorders. Huangqi Sanxian decoction (HQSXD) is utilized for the treatment of postmenopausal osteoporosis (PMOP) for a long history in East Asia. This work aimed to examine HQSXD’s activity in OC differentiation. Based on staining with tartrate-resistant acid phosphatase (TRAP), it was found that HQSXD suppressed OC generation under the induction of RANKL produced in the bone marrow-derived monocytes/macrophages (BMMs), with no cytotoxic effect. Later analysis like molecular exploration and network pharmacology (NP) suggested the role of HQSXD in suppressing genes associated with osteoclastogenesis via PI3K/Akt-mediated mechanism dose-dependently. This work might illustrate the molecular pharmacological mechanism involved in HQSXD’s effect on treating OC-associated disorders. Moreover, NP was found to modernize traditional Chinese medicine (TCM) research.

SPTBN1 Prevents Primary Osteoporosis by Modulating Osteoblasts Proliferation and Differentiation and Blood Vessels Formation in Bone

Osteoporosis is a common systemic skeletal disorder that leads to increased bone fragility and increased risk of fracture. Although βII-Spectrin (SPTBN1) has been reported to be involved in the development of various human cancers, the function and underlying molecular mechanisms of SPTBN1 in primary osteoporosis remain unclear. In this study, we first established a primary osteoporosis mouse model of senile osteoporosis and postmenopausal osteoporosis. The results showed that the expression of SPTBN1 was significantly downregulated in primary osteoporosis mice model compared with the control group. Furthermore, silencing of SPTBN1 led to a decrease in bone density, a small number of trabecular bones, wider gap, decreased blood volume fraction and number of blood vessels, as well as downregulation of runt-related transcription factor 2 (Runx2), Osterix (Osx), Osteocalcin (Ocn), and vascular endothelial growth factor (VEGF) in primary osteoporosis mice model compared with the control group. Besides, the silencing of SPTBN1 inhibited the growth and induced apoptosis of mouse pre-osteoblast MC3T3-E1 cells compared with the negative control group. Moreover, the silencing of SPTBN1 significantly increased the expression of TGF-β, Cxcl9, and the phosphorylation level STAT1 and Smad3 in MC3T3-E1 cells compared with the control group. As expected, overexpression of SPTBN1 reversed the effect of SPTBN1 silencing in the progression of primary osteoporosis both in vitro and in vivo. Taken together, these results suggested that SPTBN1 suppressed primary osteoporosis by facilitating the proliferation, differentiation, and inhibition of apoptosis in osteoblasts via the TGF-β/Smad3 and STAT1/Cxcl9 pathways. Besides, overexpression of SPTBN1 promoted the formation of blood vessels in bone by regulating the expression of VEGF. This study, therefore, provided SPTBN1 as a novel therapeutic target for osteoporosis.

MSTN is a key mediator for low-intensity pulsed ultrasound preventing bone loss in hindlimb-suspended rats

Low-intensity pulsed ultrasound (LIPUS) has been used to accelerate bone fracture healing. However, the issue whether LIPUS is effective in preventing osteoporosis has not been clarified, and if so, what possible mechanisms might be responsible. Myostatin (MSTN) is a negative regulator of muscle growth, and its absence will trigger a positive response to bone. In this study, we examined the effects of LIPUS on bone micro-structure, mechanical properties and damage healing of hindlimb-suspended rats, and investigated whether the inhibition of MSTN plays a role in this process. The rats were randomly divided into four groups: Normal control group (NC), Hind limb suspension group (HLS), Hind limb suspension and 80 mW/cm² LIPUS irradiation group (HLS+ 80 mW/cm²), Hind limb suspension and 30 mW/cm² LIPUS irradiation group (HLS+ 30 mW/cm²). The HLS+ 80 mW/cm² rats were treated with LIPUS (1 MHz, 80 mW/cm²) and the HLS+ 30 mW/cm² rats were treated with LIPUS (1 MHz, 30 mW/cm²) on the femur for 20 min/day for 28 days. MC3T3-E1 cells were respectively cultured with the serum of wild type mouse and MSTN knockout mouse at 1% concentration for 7 days. After 28 days, LIPUS effectively prevented the destruction of bone microstructure and the decline of mechanical properties, and promoted bone defect healing in the tail-suspended rats. In addition, LIPUS effectively reduced the MSTN content in the quadriceps and serum of the tail-suspended rats, inhibited its receptor and downstream signaling molecules and activated the Wnt signaling pathway in femurs. Growth of MC-3T3-E1 cell cultured with the serum of MSTN knockout mice was superior to that with wild mice serum on day 7. These results indicate that MSTN is a key mediator in LIPUS preventing bone loss caused by hindlimb-suspension.

Dynamic of miRNA-101a-3p and miRNA-200a during Induction of Osteoblast Differentiation in Adipose-derived Mesenchymal Stem Cells

miRNAs are known as the cellular phenomena regulators that exert their effects in post-transcriptional level. Recent studies highlight the role of miRNAs in mesenchymal stem cells differentiation into osteoblasts. The purpose of this study was to recognize the pattern of miRNA-101a-3p and miRNA-200a expression during osteoblastic differentiation of human adipose tissue-derived mesenchymal stem cells. The cells were incubated in osteoblastic differentiation medium for a period of 21 days. Alizarin red S staining was performed to confirm the successful differentiation of adipose-derived mesenchymal stem cells into osteoblast cells. The expression levels of miRNA-101a-3p and miRNA-200a were analyzed by real-time PCR during 0, 7, 14, and 21 days after differentiation induction. Data exhibited the increase of extracellular red color deposition which was evident at the end of the incubation period. The expression of miRNA-101a-3p and miRNA-200a was up regulated during adipose-derived mesenchymal stem cells trans-differentiation into osteoblast-like cells. These miRNAs could be potential novel biomarkers for monitoring successful differentiation of mesenchymal stem cells toward osteoblasts.

The extract of Trachelospermum jasminoides (Lindl.) Lem. vines inhibits osteoclast differentiation through the NF-κB, MAPK and AKT signaling pathways

Osteoclasts are the only cells in the body with a bone-resorption function. The identification of anti-osteoclastogenic agents is important in managing bone loss diseases. The dried vines of Trachelospermum jasminoides (Lindl.) Lem. have been used as a herbal medicine to treat musculoskeletal soreness in East Asia for hundreds of years. In the present study, we focused on the effect of Trachelospermum jasminoides (Lindl.) Lem. extract (TJE) on osteoclast differentiation. As indicated by tartrate-resistant acid phosphatase (TRAP) staining, TJE inhibited osteoclastogenesis induced by receptor activator of nuclear factor-κB ligand from bone marrow-derived monocytes/macrophages without showing any cytotoxicity. In addition, TJE effectively suppressed F-actin ring formation and the bone-resorption function of osteoclasts. The subsequent studies such as network pharmacology and molecular investigation, revealed that TJE inhibited osteoclastogenesis-related genes in a dose- and time-dependent manner through NF-κB, MAPK and AKT-mediated mechanism followed by the nuclear factor of activated T cells, cytoplasmic 1 (NFATc1)/c-Fos pathway. Our study could potentially explain the underlying molecular pharmacology of TJE in osteoclast-related diseases. What's more, it suggested that network pharmacology could help the modernization of traditional Chinese medicine.

Effect of risedronate on femoral periprosthetic bone loss following total hip replacement: A systematic review and meta-analysis

BACKGROUND

Recent study has reported that risedronate was effective in reducing periprosthesis bone loss after total hip arthroplasty (THA). The meta-analysis was performed to compare the clinical outcomes of THA with oral risedronate versus placebo.

METHODS

Electronic databases: PubMed (1950-March 2018), EMBASE (1974-March 2018), the Cochrane Central Register of Controlled Trials, Web of Science (1950-March 2018) were systematically searched. Two authors independently graded the methodological quality of each eligible study using the Cochrane Collaboration tool and extracted relevant data. Statistical heterogeneity among the trials were evaluated with chi-square and I-square tests. This meta-analysis was performed using STATA 14.0.

RESULTS

A total of 4 randomized controlled trials (RCTs) published between 2006 and 2015 were included in our study. The meta-analysis demonstrated that risedronate was associated with a significantly reduction of periprosthetic bone mineral density after THA. No increased postoperative complications were observed.

CONCLUSION

Oral risedronate might reduce the periprosthetic bone resorption after cementless THA. Additionally, no severe adverse effects were observed. High-quality RCTs with large sample size were still required.

Risedronate reduces postoperative bone resorption after cementless total hip arthroplasty: A systematic review and meta-analysis

OBJECTIVE

To examine the effects of risedronate for reducing periprosthetic bone loss after total hip arthroplasty (THA).

METHODS

Two reviewers performed an electronic literature search for randomized controlled trial (RCTs) evaluating the risedronate in the management of periprosthetic bone loss after primary THA. The electronic databases include PubMed, Medline, Embase, Web of Science and the Cochrane Library from inception to January 2018. We assessed the risk of bias using the Cochrane risk-of-bias tool. STATA 14.0 was used to perform the meta-analysis.

RESULTS

Four RCTs were included in our study. Current meta-analysis indicated that postoperative reduciton of periprosthetic BMD in the risedronate group was significantly lower than that in the placebo group in zones 1, 2, 3, 4, 6, and 7. There was no increased risk of adverse effects.

CONCLUSION

The administration of risedronate was associates with a significantly improved periprosthetic BMD after primary THA. No increased risk of adverse events were observed. Higher quality RCTs are still required for further research.