New strategies for osteoporosis patients previously managed with strontium ranelate

The Role of Sympathetic Nerves in Osteoporosis: A Narrative Review

Osteoporosis, a systemic bone disease, is characterized by decreased bone density due to various reasons, destructed bone microstructure, and increased bone fragility. The incidence of osteoporosis is very high among the elderly, and patients with osteoporosis are prone to suffer from spine fractures and hip fractures, which cause great harm to patients. Meanwhile, osteoporosis is mainly treated with anti-osteoporosis drugs that have side effects. Therefore, the development of new treatment modalities has a significant clinical impact. Sympathetic nerves play an important role in various physiological activities and the regulation of osteoporosis as well. Therefore, the role of sympathetic nerves in osteoporosis was reviewed, aiming to provide information for future targeting of sympathetic nerves in osteoporosis.

The Efficacy and Safety of Disease-Modifying Osteoarthritis Drugs for Knee and Hip Osteoarthritis-a Systematic Review and Network Meta-Analysis

BACKGROUND

Osteoarthritis (OA) is common and burdensome for patients and health care systems. Our study purpose was to evaluate the long-term efficacy and safety of DMOADs in adults with knee and hip osteoarthritis.

METHODS

We searched Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Web of Knowledge without language, publication, or date restrictions from inception through November 2018 for randomized controlled trials assessing 12 classes of DMOADs with at least 12 months of follow-up. Therapeutic effects were evaluated with pairwise and network meta-analysis. Outcomes included pain, function, minimum joint space width or cartilage volume, radiographic progression, and total joint replacement. Analyses were also performed for drug safety.

RESULTS

Twenty-eight randomized controlled trials with 11,890 patients were included. Glucosamine and chondroitin minimally improved both structure (minimum joint width or cartilage volume: network results: glucosamine: SMD 0.16; 95% CI [0.04, 0.28], chondroitin: SMD 0.21 [0.10, 0.32]) and symptoms (glucosamine: pain: - 0.15 [- 0.25, - 0.05]; function: - 0.17 [- 0.28, - 0.07], chondroitin: pain: - 0.06 [- 0.15, 0.03], and function: - 0.15 [- 0.26, - 0.03]). Strontium demonstrated improvement in structure (minimum joint width or cartilage volume: 0.20 [0.02, 0.38]), and vitamin D on symptoms (pain: - 0.15 [- 0.27, -0.03]; function: - 0.18 [- 0.31, - 0.06]). Although doxycycline also demonstrated a favorable efficacy ranking, its safety profile was poor (withdrawal: network relative risk 1.69 [1.03, 2.75]). The therapeutic effects of other medications were not ranked as highly.

DISCUSSION

Glucosamine and chondroitin yielded statistically significant but clinically questionable long-term benefit on structure and symptoms, though both had favorable safety profiles. Strontium improved structure, and vitamin D improved symptoms. Although doxycycline had a favorable efficacy ranking, its safety profile was poor. None of the 12 classes of drugs appears to have long-term clinically significant benefit.

The role of strontium ranelate and guided bone regeneration in osteoporotic and healthy conditions

BACKGROUND/ OBJECTIVES

SR is a chemical agent developed for the treatment of osteoporosis. In vitro, SR enhanced replication of osteoprogenitor cells and bone formation. In vivo, in ovariectomized rats SR prevented the biomechanical deterioration of bone while in non-ovariectomized rats, enhanced bone architecture and increased trabecular and cortical bone mass. The aim of this study was to evaluate the effect of SR on bone healing of calvarial critical size defects treated with a deproteinized bovine bone mineral (DBBM) and a collagen barrier (CM), in healthy and osteoporotic rats.

MATERIAL AND METHODS

Sixty-four, 4-month-old Wistar female rats were used. Osteoporosis was induced by ovariectomy and calcium-deficient diet in half of them. Sixteen ovariectomized (OSR) and 16 healthy (HSR) rats were treated with SR while no medication was administered in the remaining 16 healthy (H) and 16 ovariectomized (O) rats. At 6 weeks after ovariectomy, a 5mm defect was created in each parietal bone of every animal. One defect was treated with DBBM and CM, while the contralateral was left untreated. Qualitative and quantitative histological analysis was performed at 30 and 60 days of healing. A generalized estimating equations test was performed to evaluate the effect of SR and osteoporosis, on new bone formation (NB).

RESULTS

After 30 days of healing, NB in the untreated defects was 3.4%±1.7%, 4.3%±6.2%, 3.2±4.5%, 15.9±23.5% in O, OSR, H and HSR groups, respectively; after 60 days, NB was 4.7%±4.3%, 11.3%±7%, 7.1%±13.2, 12.1%±13.5%, respectively. In the GBR-treated defects, after 30 days, NB was 2.6%±1.4%, 2.4%±1.6%, 4.5%±4.1%, 10.3%±14.4% in O, OSR, H and HSR groups, respectively; after 60 days, NB was 2.2%±1.6%, 4.3%±4.2%, 7%±5.1%, 10.8%±17.4%, respectively. Osteoporosis (p=0.008) and the absence of strontium ranelate treatment (p=0.01) had a negative impact on NB.

CONCLUSION

SR may promote bone formation in calvarial defects in healthy and osteoporotic rats, albeit in a moderate extent.

Effects of Strontium-Doped β-Tricalcium Scaffold on Longitudinal Nuclear Factor-Kappa Beta and Vascular Endothelial Growth Factor Receptor-2 Promoter Activities during Healing in a Murine Critical-Size Bone Defect Model

It was hypothesized that strontium (Sr)-doped β-tricalcium phosphate (TCP)-based scaffolds have a positive effect on the regeneration of large bone defects (LBD). Readouts in our mice models were nuclear factor-kappa beta (NF-κB) activity and vascular endothelial growth factor receptor-2 (VEGFR-2) promoter activity during the healing process. A 2-mm critical-size femoral fracture was performed in transgenic NF-κB- and VEGFR-2-luciferase reporter mice. The fracture was filled with a 3D-printed β-TCP scaffold with or without Sr. A bioluminescence in-vivo imaging system was used to sequentially investigate NF-κB and VEGFR-2 expression for two months. After sacrifice, soft and osseous tissue formation in the fracture sites was histologically examined. NF-κB activity increased in the β-TCP + Sr group in the latter stage (day 40–60). VEGFR-2 activity increased in the + Sr group from days 0–15 but decreased and showed significantly less activity than the β-TCP and non-scaffold groups from days 40–60. The new bone formation and soft tissue formation in the + Sr group were significantly higher than in the β-TCP group, whereas the percentage of osseous tissue formation in the β-TCP group was significantly higher than in the β-TCP + Sr group. We analyzed longitudinal VEGFR-2 promoter activity and NF-κB activity profiles, as respective agents of angiogenesis and inflammation, during LBD healing. The extended inflammation phase and eventually more rapid resorption of scaffold caused by the addition of strontium accelerates temporary bridging of the fracture gaps. This finding has the potential to inform an improved treatment strategy for patients who suffer from osteoporosis.

Strontium ranelate as a possible disease-modifying osteoarthritis drug: a systematic review

Considering that osteoarthritis (OA) is the most prevalent joint disease worldwide, multiple pharmacological treatments have been proposed to alter the articular structure with potential benefit in the progression of the disease. The so-called disease-modifying OA drugs have been frequently investigated but conclusive findings are rare. Strontium ranelate (SrRan) is a drug usually prescribed to treat osteoporosis, with proven effects in decreasing the risk of fractures and possible effect in reducing the progression of OA. The objective of this review was to demonstrate the current panorama of knowledge on the use of SrRan in clinical and experimental models, clarifying its mechanisms of action and describing possible anti-nociceptive and anti-inflammatory effects. The systematic review was based on the PRISMA statement and included articles that are indexed in scientific databases. Fifteen studies were included: seven pre-clinical and eight clinical studies. Despite the limited number of studies, the results suggest a positive effect of SrRan in patients with OA, through changes in functional capacity and reduction of progression of morphological parameters and joint degradation, with moderate quality of evidence for those clinical outcomes. Novel studies are necessary to elucidate the molecular targets of SrRan, focusing on anti-inflammatory effects and histological changes promoted by SrRan, which seemed to reduce the progression of OA in the experimental and clinical studies.

Low-dose strontium stimulates osteogenesis but high-dose doses cause apoptosis in human adipose-derived stem cells via regulation of the ERK1/2 signaling pathway

Background

Strontium is a widely used anti-osteoporotic agent due to its dual effects on inhibiting bone resorption and stimulating bone formation. Thus, we studied the dose response of strontium on osteo-inductive efficiency in human adipose-derived stem cells (hASCs).

Method

Qualitative alkaline phosphatase (ALP) staining, quantitative ALP activity, Alizarin Red staining, real-time polymerase chain reaction and Western blot were used to investigate the in vitro effects of a range of strontium concentrations on hASC osteogenesis and associated signaling pathways.

Results

In vitro work revealed that strontium (25–500 μM) promoted osteogenic differentiation of hASCs according to ALP activity, extracellular calcium deposition, and expression of osteogenic genes such as runt-related transcription factor 2, ALP, collagen-1, and osteocalcin. However, osteogenic differentiation of hASCs was significantly inhibited with higher doses of strontium (1000–3000 μM). These latter doses of strontium promoted apoptosis, and phosphorylation of ERK1/2 signaling was increased and accompanied by the downregulation of Bcl-2 and increased phosphorylation of BAX. The inhibition of ERK1/2 decreased apoptosis in hASCs.

Conclusion

Lower concentrations of strontium facilitate osteogenic differentiation of hASCs up to a point; higher doses cause apoptosis of hASCs, with activation of the ERK1/2 signaling pathway contributing to this process.

Comparison of parathyroid hormone and strontium ranelate in combination with whole-body vibration in a rat model of osteoporosis

We investigated the combinatorial effects of whole-body vertical vibration (WBVV) with the primarily osteoanabolic parathyroid hormone (PTH) and the mainly antiresorptive strontium ranelate (SR) in a rat model of osteoporosis. Ovariectomies were performed on 76 three-month-old Sprague-Dawley rats (OVX, n = 76; NON-OVX, n = 12). After 8 weeks, the ovariectomized rats were divided into 6 groups. One group (OVX + PTH) received daily injections of PTH (40 µg/kg body weight/day) for 6 weeks. Another group (OVX + SR) was fed SR-supplemented chow (600 mg/kg body weight/day). Three groups (OVX + VIB, OVX + PTH + VIB, and OVX + SR + VIB) were treated with WBVV twice a day at 70 Hz for 15 min. Two groups (OVX + PTH + VIB, OVX + SR + VIB) were treated additionally with PTH and SR, respectively. The rats were killed at 14 weeks post-ovariectomy. The lumbar vertebrae and femora were removed for biomechanical and morphological assessment. PTH produced statistically significant improvements in biomechanical and structural properties, including bone mineral density (BMD) and trabecular bone quality. In contrast, SR treatment exerted mild effects, with significant effects in cortical thickness only. SR produced no significant improvement in biomechanical properties. WBVV as a single or an adjunctive therapy produced no significant improvements. In conclusion, vibration therapy administered as a single or dual treatment had no significant impact on bones affected by osteoporosis. PTH considerably improved bone quality in osteoporosis cases and is superior to treatment with SR.