Effect of a local, one time, low-dose injection of zoledronic acid on titanium implant osseointegration in ovariectomized rats

An Evaluation of the Effectiveness of Local Delivery of Zoledronic Acid in Accelerating Bone Healing After the Extraction of Mandibular Third Molars

Background and objective Zoledronic acid (ZA) has been reported to aid with the formation of new bone, inhibit osteoclastic bone resorption, and improve osteoblast proliferation. This split-mouth randomized clinical research aimed to evaluate the effect of the local application of ZA on bone regeneration after the removal of bilateral mandibular third molars. Methods A randomized, split-mouth study involving 12 patients aged 19-35 years requiring extraction of bilaterally mandibular third molars was conducted. The extraction of mandibular third molars on both sides was conducted in one session for all patients. In each participant, a gelatin sponge (Gelfoam) soaked with ZA was randomly applied to one cavity of the extraction socket. A gelatin sponge soaked with normal saline was applied to the opposite cavity; all patients were blinded as to which socket the drug was applied to. The study was conducted over a period of two months. The changes in bone density (BD) in the socket were assessed through cone-beam CT (CBCT) images; two images were taken for each patient at two different time points: immediately after extraction (T0) and after two months (T1). Results BD values in the socket on both sides of extraction increased from T0 to T1. There were statistically significant differences when comparing the amount of change in radiographic BD from T0 to T1 between the two sides of the extraction (p<0.05); the increase in radial BD between the two different time points was more significant in the ZA group. Conclusions Within the limitation of this study, the local application of ZA radiographically improved bone healing in a statistically significant manner and could be a cost-effective and simple way to activate bone regeneration.

Beneficial effect of pristimerin against the development of osteoporosis in ovariectomy-induced osteoporosis rats by the RANKL/TRAF6/NF-κB pathway

INTRODUCTION

Osteoporosis is a major cause of bone fracture in post-menopausal women. We evaluated the effects of pristimerin treatment on ovariectomy-induced osteoporosis, and its possible molecular mechanism.

MATERIAL AND METHODS

Rats were ovariectomised and biochemical markers of bone formation were determined from serum samples. The microarchitectures of bone tissues were analyzed via micro-CT scans and Western blotting assays. The cytotoxic effects of pristimerin, the differentiation of osteoclasts, and bone reabsorption were evaluated in vitro using RAW 264.7 cells.

RESULTS

Treatment with pristimerin attenuated changes in markers of bone formation and reabsorption such as creatine kinase (CK), alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP), collagen type I fragments (CTX), bone Gla-protein (BGP), and osteocalcin (OC) in the serum of ovariectomised rats. It also appeared to restore the microarchitecture of bone tissue. The expression levels of TNF receptor-associated factor 6 (TRAF-6), nuclear factor κ light chain enhancer of activated B cells (NF-κB p65), and receptor activator of nuclear factor-κB ligand (RANKL) protein were significantly lower, while those of Akt and PI3K were significantly higher, in the bone tissues of the pristimerin-treated group than in negative controls. Pristimerin had no cytotoxic effect on RAW 264.7 cells and reduced the differentiation of osteoclasts, bone reabsorption, and translocation of p65 in RANKL-stimulated RAW 264.7 cells in vitro.

CONCLUSIONS

Pristimerin reduces the effects of osteoporosis by restoring the altered RANKL/TRAF-6/NF-κB pathway in ovariectomised rats.

MALAT1/miR-320a in bone marrow mesenchymal stem cells function may shed light on mechanisms underlying osteoporosis

INTRODUCTION

Growing evidence supports the involvement of long noncoding RNAs (lncRNAs) in bone metabolism and diseases. This study aims to investigate the involvement of the lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the pathological process of osteoporosis and the effects of MALAT1 on regulation of BMSC differentiation through competitive endogenous RNA (ceRNA) mechanisms.

MATERIAL AND METHODS

The expression of MALAT1 and miR-320a was determined using RT-PCR in bone tissue derived from female SD (Sprague Dawley) rats with osteoporosis. Immunohistochemical (IHC) staining was used to evaluate the expression of neuropilin-1 (NRP-1) and β-catenin. Bone marrow mesenchymal stem cells (BMSCs) were divided into 4 groups: control, NC (negative control), MALAT1 siRNA, and miR-320a mimics. Forty-eight hours later, the effect of MALAT1 on the miR-320a expression, proliferation and osteogenic differentiation of BMSCs was investigated. Two weeks later, the cell activity, alkaline phosphatase (ALP) activity, and mRNA expression of Osterix and Runx2 were evaluated. Three weeks later, alizarin red staining of calcified nodules and Western blot analysis of the expression of β-catenin, NRP-1, osteocalcin (OCN), and osteopontin (OPN) were performed.

RESULTS

Downregulated MALAT1or upregulated miR-320a expression inhibited the activity and osteogenic differentiation of BMSCs, resulting in low ALP activity and NRP-1 expression, fewer calcified nodules, decreased mRNA levels of Osterix and Runx2, and inhibited expression of NRP-1, OCN, and OPN. MALAT1 silencing did not decrease the protein level of β-catenin in the cytoplasm but suppressed that in the nucleus.

CONCLUSIONS

Downregulated MALAT1 and upregulated miR-320a expression play an important role in the pathological process of osteoporosis, via inhibition of the osteogenic differentiation of BMSCs.

Effect of Primary Stabilisation on Osseointegration of Implants With Local and Systemic Zoledronic Acid Application

ABSTRACT

Primary stabilization (PS) is defined as initial tight fit during the surgical placement of an implant. Tight implant placement is quite difficult in cases where bone quality and quantity are insufficient. Zoledronic acid (ZA) is a powerful bisphosphonate that prevents bone resorption. The aim of this study is to investigate the effect of local and systemic ZA application on osseointegration in titanium implants with and without PS. Male Sprague Dawley rats were divided into 2 main groups, with PS, PS + (n = 24), and without primary stabilisation, PS - (n = 24). These main groups were divided into control (n = 8), 2 mg/1 mL local ZA (n = 8) and 0.1 mg/kg systemic ZA (n = 8) groups. All of the subjects were sacrificed after a 4-week recovery period. Bone implant connection (BIC) and thread filling (TF) (%) of the samples was analyzed according to the non-decalcified histological analysis method. In terms of BIC percentages and TF, statistically significant differences were found between the groups with and without PS and between the ZA treatment groups (P < 0.05). The common effect of PS and ZA use on the percentage of BIC was found to be statistically significant (P < 0.05). The common effect of PS and acid type on TF was not statistically significant (P < 0.05). Within the limitations of this study, it may be concluded that systemic and local administration of ZA may increase implant osseointegration.

Histomorphometric Evaluation of Peri-Implant Bone Response to Intravenous Administration of Zoledronate (Zometa®) in an Osteoporotic Rat Model

We evaluated the response to peri-implant bone placed in the femoral condyle of osteoporotic rats, following intravenous zoledronate (ZOL) treatment in three settings: pre-implantation (ZOL-Pre), post-implantation (ZOL-Post), and pre- + post-implantation (ZOL-Pre+Post). Twenty-four female Wistar rats were ovariectomized (OVX). After 12 weeks, the rats received titanium implants in the right femoral condyle. ZOL (0.04 mg/kg, weekly) was administered to six rats 4 weeks pre-implantation and was stopped at implant placement. To another six rats, ZOL was given post-implantation and continued for 6 weeks. Additional six rats received ZOL treatment pre- and post-implantation. Control animals received weekly saline intravenous injections. At 6 weeks post-implantation, samples were retrieved for histological evaluation of the percentage of bone area (%BA) and of the percentage of bone-to-implant contact (%BIC). BA% for ZOL-Pre (29.6% ± 9.0%) and ZOL-Post (27.9% ± 5.6%) rats were significantly increased compared to that of the controls (17.3% ± 3.9%, p < 0.05). In contrast, ZOL-Pre+Post rats (20.4% ± 5.0%) showed similar BA% compared to Saline controls (p = 0.731). BIC% revealed a significant increase for ZOL-Post (65.8% ± 16.9%) and ZOL-Pre+Post (68.3% ± 10.0%) rats compared with that of Saline controls (43.3% ± 9.6%, p < 0.05), while ZOL-Pre rats (55.6% ± 19%) showed a BIC% comparable to that of Saline controls (p = 0.408). Our results suggest that receiving intravenous ZOL treatment before or after implant placement enhances peri-implant bone responses in terms of bone area. However, the effect of different ZOL treatment regimens on BIC% was found to be inconclusive.

Effects of Systemic or Local Administration of Zoledronate on Implant Osseointegration: A Preclinical Meta-Analysis

Objective

This study aims to investigate the effect of systemically administrated zoledronate on bone-implant fixation in animal models.

Methods

We searched MEDLINE, Embase, and EBSCO for studies that explore the role of systemic or local zoledronate delivery in implant osseointegration in animal models. The Review Manager software was used to analyze selected studies by using the weighted mean difference random-effects model. Analytical data are mainly about bone ingrowth, such as bone-to-implant contact (BIC), bone volume/total volume (BV/TV), and bone area.

Results

Twenty studies were selected from 182 publications. The mean quality score was 18/20 for all of the 20 studies (κ = 0.9). Despite differences in protocols, these studies showed consistent improvement of implant osseointegration with zoledronate administration. In addition, the osteoporotic animal model, systemic or local administration, sufficient drug dosage, and sample follow-up time were correlated with improved outcomes.

Conclusion

Systematic administration of zoledronate could improve the osseointegration of orthopedic implant in animal models. Results of this meta-analysis should be interpreted cautiously because of the inherent differences between preclinical and clinical subjects. For the local administration, there is a similar trend as well, but the results need to be confirmed and complemented with further analyses.

Microcirculatory consequences of limb ischemia/reperfusion in ovariectomized rats treated with zoledronic acid

Background

Nitrogen-containing bisphosphonates (BIS) are potent therapeutics in osteoporosis, but their use may result in osteonecrotic side-effects in the maxillofacial region. Periosteal microcirculatory reactions may contribute to the development of bone-healing complications, particularly in osteoporotic bones, where ischemia–reperfusion (IR) events often develop during orthopaedic/trauma interventions. The effect of BIS on the inflammatory reactions of appendicular long bones has not yet been evaluated; thus, we aimed to examine the influence of chronic zoledronate (ZOL) administration on the periosteal microcirculatory consequences of hindlimb IR in osteopenic rats.

Materials and methods

Twelve-week-old female Sprague–Dawley rats were ovariectomized (OVX) or sham-operated, and ZOL (80 μg/kg iv, weekly) or a vehicle was administered for 8 weeks, 4 weeks after the operation. At the end of the pre-treatment protocols, 60-min limb ischemia was induced, followed by 180-min reperfusion. Leukocyte-endothelial interactions were quantitated in tibial periosteal postcapillary venules by intravital fluorescence videomicroscopy. CD11b expression of circulating polymorphonuclear leukocytes (PMN, flow cytometry) and plasma TNF-alpha levels (ELISA) were also determined. Two-way RM ANOVA followed by the Holm–Sidak and Dunn tests was used to assess differences within and between groups, respectively.

Results

Limb IR induced significant increases in PMN rolling and firm adhesion in sham-operated and OVX rats, which were exacerbated temporarily in the first 60 min of reperfusion by a ZOL treatment regimen. Postischemic TNF-alpha values showed a similar level of postischemic elevations in all groups, whereas CD11b expression only increased in rats not treated with ZOL.

Conclusions

The present data do not show substantial postischemic periosteal microcirculatory complications after chronic ZOL treatment either in sham-operated or OVX rats. The unaltered extent of limb IR-induced local periosteal microcirculatory reactions in the presence of reduced CD11b adhesion molecule expression on circulating PMNs, however, may be attributable to local endothelial injury/activation caused by ZOL.

Comparison of Osseointegration of Five Different Surfaced Titanium Implants

The topography, chemical features, surface charge, and hydrophilic nature of titanium implant surfaces are crucial factors for successful osseointegration. This study aimed to investigate the bone implant contact (BIC) ratio of titanium dental implants with different surface modification techniques using the rat femoral bone model. Sandblasted and acid washed (SL-AW), sandblasted (SL), resorbable blast material (RBM), microarc (MA), and sandblasted and microarc (SL-MA) surfaces were compared in this study. Forty male Sprague-Dawley rats were used in this study. The rats were divided into 5 equal groups (n = 8), and totally 40 implants were integrated into the right femoral bones of the rats. The rats were sacrificed 12 weeks after the surgical integration of the implants. The implant surface-bone tissue interaction was directly observed by a light microscope, and BIC ratios were measured after the nondecalcified histological procedures. Bone implant contact ratios were determined as follows: SL-AW: 59.26 ± 14.36%, SL: 66.01 ± 9.63%, RBM: 63.53 ± 11.23%, MA: 65.51 ± 10.3%, and SL-MA: 68.62 ± 6.6%. No statistically significant differences were found among the 5 different surfaced titanium implant groups (P > 0.05). Our results show that various implant surface modification techniques can provide favorable bone responses to the BIC of dental implants.

Anabolic and antiresorptive actions of locally delivered bisphosphonates for bone repair: A review

During the last decades, several research groups have used bisphosphonates for local application to counteract secondary bone resorption after bone grafting, to improve implant fixation or to control bone resorption caused by bone morphogenetic proteins (BMPs). We focused on zoledronate (a bisphosphonate) due to its greater antiresorptive potential over other bisphosphonates. Recently, it has become obvious that the carrier is of importance to modulate the concentration and elution profile of the zoledronic acid locally. Incorporating one fifth of the recommended systemic dose of zoledronate with different apatite matrices and types of bone defects has been shown to enhance bone regeneration significantly in vivo. We expect the local delivery of zoledronate to overcome the limitations and side effects associated with systemic usage; however, we need to know more about the bioavailability and the biological effects. The local use of BMP-2 and zoledronate as a combination has a proven additional effect on bone regeneration. This review focuses primarily on the local use of zoledronate alone, or in combination with bone anabolic factors, in various preclinical models mimicking different orthopaedic conditions.

Cite this article: I. Qayoom, D. B. Raina, A. Širka, Š. Tarasevičius, M. Tägil, A. Kumar, L. Lidgren. Anabolic and antiresorptive actions of locally delivered bisphosphonates for bone repair: A review. Bone Joint Res 2018;7:548–560. DOI: 10.1302/2046-3758.710.BJR-2018-0015.R2.

Effect of lycopene on titanium implant osseointegration in ovariectomized rats

Background

Lycopene prevents bone loss in osteopenic models. However, the role of lycopene in the success rate of dental implants under osteopenic conditions remains unknown. The aim of this study was to evaluate whether lycopene prevents delayed implant osseointegration in an ovariectomized (OVX) rat model.

Methods

Thirty female Sprague-Dawley rats were randomly divided into the following groups: OVX with vehicle (OVX group), OVX with lycopene (OVX + lycopene group) and sham-operated with vehicle (sham group). Twelve weeks after ovariectomy or sham operation, titanium implants were placed into the distal metaphysis of the bilateral femurs of each rat. These rats were subsequently gavaged with lycopene (50 mg/kg/day) or vehicle. After 12 weeks of gavage, all rats were sacrificed, and specimens were harvested. Sample osseointegration was evaluated by biomechanical testing, 3D micro-computed tomography (micro-CT) analysis and histomorphometric analysis.

Results

Compared with the OVX group, the OVX + lycopene group showed a 69.3% increase in the maximum push-out force (p < 0.01). Micro-CT data for the femurs in the OVX + lycopene group showed significantly higher bone volume, trabecular thickness and less trabecular space than did those in the OVX group. The bone area (BA) around the implant and bone contact (BC) with the implant were increased by 72.3% (p < 0.01) and 51.4% (p < 0.01) in the OVX + lycopene group, respectively, compared with those in the OVX group. There was no significant difference in the mechanical test, micro-CT scanning and histomorphometric data between the OVX + lycopene and sham groups (p > 0.05).

Conclusions

Lycopene improved implant osseointegration, fixation and bone formation under osteopenic conditions, suggesting that lycopene is a promising therapeutic agent to prevent delayed implant osseointegration and bone loss under osteopenic conditions.

The effect of ovariectomy and 2 antiresorptive therapeutic agents on bone response in rats: A 3-dimensional imaging analysis

OBJECTIVE

The aim of this study was to evaluate bone mineral density (BMD) and microarchitecture in femurs and maxillary bones of ovariectomized (OVX) rats treated or not treated with alendronate (ALD) or odanacatib (ODN).

STUDY DESIGN

Twenty rats were divided into groups: SHAM, OVX, OVX/ALD, and OVX/ODN. After 12 weeks, the femurs and maxillae were removed and subjected to 3-dimensional analysis by micro-computed tomography. Results were analyzed with 1-way analysis of variance and Tukey's post hoc test (α = 0.05).

RESULTS

OVX decreased maxillary and femoral BMD and altered femoral microarchitecture (P < .05). The drugs increased BMD of both types of bones, but only ALD maintained the phenotype similar to the SHAM group. The action of ALD was limited to the femoral trabecular separation (Tb.Sp). OVX and the drugs had no effect on the microarchitecture of the maxilla (P > .05).

CONCLUSIONS

ALD and ODN therapy increased BMD in both bones after ovariectomy. ALD was more successful than ODN in preserving the morphology of bone similar to the SHAM group. ALD maintained the phenotype for Tb.Sp in the femur, but ODN did not. In the maxillae, neither ovariectomy nor the 2 antiresorptive drugs had significant effects on microarchitecture.

Effect of local zoledronate delivery on osseointegration: a systematic review of preclinical studies

PURPOSE

The aim of the present systematic review was to assess the effect of local zoledronate (ZOL) delivery (topical or as implant surface coatings) on osseointegration.

MATERIALS AND METHODS

In this systematic review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. To address the focused question, 'Does local zoledronate delivery enhance osseointegration?' indexed databases were searched without time or language restrictions up to and including April 2017 using various combination of the following keywords: 'zoledronate', 'bisphosphonates', 'osseointegration' and 'topical administration'. Letters to the Editor, historic reviews, commentaries, case-series and case-reports were excluded.

RESULTS

Initially, 383 articles were identified out of which, 23 experimental studies fulfilled the inclusion criteria. In 18 studies, ZOL was incorporated into implants surfaces as a coating and in five studies ZOL was applied topically (bone graft or irrigation) into the bone cavities. Results from 87% studies reported that local delivery of ZOL (coating or topical) is effective in enhancing osseointegration or new bone formation around implants.

CONCLUSIONS

Local ZOL delivery (coating or topical) seems to enhance osseointegration in animals; however, from a clinical perspective, further randomized control trials with long-term follow-up are needed in this regard.