[Introduction to bisphosphonates. History and functional mechanisms]

Efficacy of the systemic co-administration of vitamin D3 in reversing the inhibitory effects of sodium alendronate on orthodontic tooth movement: A preliminary experimental animal study

INTRODUCTION

Bisphosphonates can severely slow down orthodontic tooth movement (OTM) by reducing bone turnover. This calls for materials and methods to reverse or neutralize their effects on OTM. We propose systemic vitamin D3 (D3) for this purpose.

METHODS

Thirty-two male Wistar rats were randomized into 4 groups of 8 each. Three groups were administered D3 (3 systemic doses of 24,000 IU/kg each), alendronate (ALN) (5 doses of 7 mg/kg each), and ALN+D3 (same doses as mentioned above). One group served as the negative control. The incisors were distalized at 30 g of force for 2 weeks. OTMs were measured blindly. Radicular pressure areas were searched histologically (blindly) for capillaries, Howship's lacunae, osteoclasts, and osteoblasts. Data were analyzed statistically (α = 0.05, α = 0.0083, β <0.1).

RESULTS

OTMs in the groups D3, ALN+D3, ALN, and control were 1.900 ± 0.237, 1.629 ± 0.219, 0.975 ± 0.145, and 1.565 ± 0.324 mm (analysis of variance, P <0.001), respectively. OTM in the ALN group was smaller than all other groups (Tukey, P <0.001). OTM in the D3 group was greater than in the control group (P = 0.054). The ALN+D3 group had greater OTM than the ALN group (P <0.001) but was not significantly different from the D3 (P = 0.153) or control (P = 0.951) groups. All histologic variables were significantly different across groups (Kruskal-Wallis, P <0.001). All the markers in the D3 group were more frequent than those of the other groups (Mann-Whitney U, P <0.001). There were fewer markers in the ALN group than in the control group (P ≤0.001). The ALN+D3 group had more markers than the ALN group in terms of capillaries, osteoclasts, and osteoblasts (P ≤0.007). The ALN+D3 group was similar to the control group regarding capillaries, osteoclasts, and osteoblasts (P ≥0.382).

CONCLUSIONS

Systemic vitamin D3 may accelerate OTM and increase histologic biomarkers of bone turnover. ALN reduces OTM and its histologic biomarkers. Systemic vitamin D3 can reverse this inhibitory effect of ALN on OTM back to normal.

Zoledronic Acid-Loaded β-TCP Inhibits Tumor Proliferation and Osteoclast Activation: Development of a Functional Bone Substitute for an Efficient Osteosarcoma Treatment

Osteosarcoma has a poor survival rate due to relapse and metastasis. Zoledronic acid (ZOL), an anti-resorptive and anti-tumor agent, is used for treating osteosarcoma. Delivery of ZOL to the target region is difficult due to its high binding affinity to bone minerals. This study developed a novel treatment for osteosarcoma by delivering ZOL to the target region locally and sustainably. In this study, we fabricated a novel bone substitute by loading ZOL on β-tricalcium phosphate (β-TCP). The ZOL-loaded β-TCP (ZOL/β-TCP) would be expected to express the inhibitory effects via both bound-ZOL (bound to β-TCP) and free-ZOL (release from ZOL/β-TCP). To explore the ability to release ZOL from the ZOL/β-TCP, the amount of released ZOL was measured. The released profile indicates that a small amount of ZOL was released, and most of it remained on the β-TCP. Our data showed that ZOL/β-TCP could successfully express the effects of ZOL via both bound-ZOL and free-ZOL. In addition, we examined the biological effects of bound/free-ZOL using osteosarcoma and osteoclasts (target cells). The results showed that two states of ZOL (bound/free) inhibit target cell activities. As a result, ZOL/β-TCP is a promising candidate for application as a novel bone substitute.

Determination of Zoledronic Acid and Its Related Substances by High Performance Liquid Chromatography with Evaporative Light Scattering Detection

A method has been developed and validated for analysis of zoledronic acid (ZOL) and its related substances by ion-pair reversed-phase high performance liquid chromatography with evaporative light scattering detection (ELSD). Chromatographic separation was achieved with gradient elution by using a C18 column, mobile phase containing 12 mM ammonium acetate buffer and 35 mM n-pentylamine, whose pH value is 7.0, and 5% acetonitrile. The mobile-phase flow rate was 1.0 mL/min. The calibration plot was linear in the range from 0.4 mg/mL to 6.0 mg/mL for ZOL and from 6.25 μg/mL to 100 μg/mL for its related substances. ZOL and its related substances, namely imidazole-1-yl-acetic acid, phosphate, phosphite and degradation products did not interfere with each other. The method was rapid, linear, accurate and reproducible. The high performance liquid chromatographic method that has been developed to determine the related substances and assay of ZOL can be used simultaneously to evaluate the quality of regular samples. It can be also used to test the stability samples of ZOL.

Management of severe osteoporosis

INTRODUCTION

Severe osteoporosis represents a disease of high mortality and morbidity. Recognition of what constitutes and causes severe osteoporosis and aggressive intervention with pharmacological agents with evidence to reduce fracture risk are outlined in this review.

AREAS COVERED

This review is a blend of evidence obtained from literature searches from PubMed and The National Library of Medicine (USA), clinical experience and the author's opinions. The review covers the recognition of what constitutes severe osteoporosis, and provides up-to-date references on this sub-set of high risk patients.

EXPERT OPINION

Severe osteoporosis can be classified by using measurements of bone densitometry, identification of prevalent fractures, and, knowledge of what additional risk factors contribute to high fracture risk. Once recognized, the potential consequences of severe osteoporosis can be mitigated by appropriate selection of pharmacological therapies and modalities to reduce the risk for falling.

Surgical treatment of bisphosphonate-associated osteonecrosis: Prognostic score and long-term results

Over a century after the first synthesis of bisphosphonates (1897) and a decade (2003) since the initial report on bisphosphonate-related osteonecrosis of the jaw (ONJ), this osteopathy remains a serious clinical challenge. A single center longitudinal study (2005-2014) was carried out to prospectively characterize inpatients with manifest ONJ and to evaluate their outcomes. The data recorded were: medical history, bisphosphonate treatment, localization, imaging, treatment, histomorphological features, and complications. A prognostic score (modified UCONN-Score) was adopted to predict outcomes. Eighty patients were included (mean age 69.4 years; 40 male, 40 female). Breast cancer (n = 25), multiple myeloma (n = 16), and prostate cancer (n = 15) were the three most common malignancies; and cardiovascular disease (n = 31), diabetes mellitus (16), and renal disorders (6) were the most important comorbidities. The severity of ONJ was stage I in three patients, stage II in 37, and stage III in 40, being predominantly localized in the posterior mandible and needing gradual resection. The average duration of bisphosphonate treatment was 38.3 months. The typical histological aspects of ONJ were predominantly osteonecrosis, bone marrow fibrosis, and bacterial colonization (Actinomyces) with suppurative inflammation. Within the resected jawbone a primary malignancy was diagnosed in two cases. The overall success rate was 83.6% (follow-up 23.5 months), with a UCONN-Score ≥15 predicting unfavorable treatment results (OR = 5.2). The past decade has enhanced experience with ONJ treatment and knowledge about its pathogenesis, which seems to be a multistep process. This study demonstrates the importance of bone and multilayer soft tissue management, preferably as an early intervention. The UCONN-Score might help to assess individual prognosis in ONJ surgery and the potential benefit of an antiresorptive drug holiday. To our knowledge it is the first use of a prognostic score in ONJ surgery.

Osteochemonecrosis: an overview

Osteonecrosis of the jaw to a certain extent has been with us for many years. But recently the advent of various medications such as bisphosphonates, VEGF inhibitors, tyrosine kinase inhibitors and humanized antibodies to osteoclastic action have resulted in thousands of cases. While the bisphosphonates continue to be the most common medication associated with osteochemonecrosis antibodies such as denosumab which irreversibly act on osteoclastic action are also being reported. This narrative review will serve as an update with a focus on some of the histopathologic features discussed and reviewed. Perhaps even more uncommonly seen in past reports a discussion of features possibly observed while grossing specimens will be discussed. At the end of this report is hoped that the pathologist will have a better understanding of the historical features, clinical settings, gross examination features as well as histopathologic features associated with osteochemonecrosis.

Effects of intra-articular clodronate in the treatment of knee osteoarthritis: results of a double-blind, randomized placebo-controlled trial

Aim of this study was to evaluate the efficacy and tolerability of intra-articular (IA) clodronate, compared to saline solution, in patients with symptomatic knee osteoarthritis (KOA). In this double-blind phase 3 randomized clinical trial, patients were randomized to receive once weekly IA injection of 2 mg clodronate or placebo for 4 weeks with 12 weeks of follow-up. The primary objective was the sum of spontaneous, on passive movement, and at digital pressing pain relief assessed by visual analogue score (VAS) of 0-100 at 5 weeks after the final injection. Improving in Western Ontario MacMaster (WOMAC) scale, Lequesne index, consumption of acetaminophen, and physician or patient overall judgment were secondary objectives. Study population included 80 patients, 67 women and 13 men aged 66 ± 6 (SD) years. A significant improvement for all efficacy parameters was observed at all-time points in both groups. A significant difference in favor to clodronate in VAS for pain was observed 5 weeks after the last injection (-114.6 vs. -87.2 for clodronate and placebo group, respectively; p < 0.05). The improvements in Lequesne index, global KOA evaluation from both patients and investigators, and the WOMAC pain subscale were significantly greater in the clodronate group. The proportion of patients that did not require acetaminophen was significantly greater in the clodronate group (about 10 vs. 30 % for clodronate and placebo group, respectively; p < 0.05). IA 2 mg clodronate is associated with small and transient symptomatic and functional benefits and it is safe in KOA patients.

Effect of dental implants on bisphosphonate-related osteonecrosis of the jaws

PURPOSE

Bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) is a side effect of BP therapy. Dental implants are believed to be a risk factor for developing BRONJ. In the present study, we analyzed the interval to the development of BRONJ in patients treated with BP who had received dental implants.

PATIENTS AND METHODS

Patients with dental implants and established BRONJ were evaluated at the oral and maxillofacial surgery department (Medical University of Vienna). In addition, studies from 1978 to 2012 were included in a meta-analysis. Three groups were created: implantation before BP treatment, implantation after BP treatment, and implantation during BP treatment. The outcomes were evaluated using linear regression analysis.

RESULTS

Patients who underwent dental implantation during (P < .001) and after (P < .001) treatment with BPs developed BRONJ more rapidly. The treatment duration with oral BPs was significantly related to the rapidity of developing BRONJ (P = .03).

CONCLUSIONS

The insertion of dental implants during or after BP treatment accelerated the development of BRONJ. BRONJ occurred less frequently when the implants had been inserted before BP therapy had been started.

Drug intercalation in layered double hydroxide clay: application in the development of a nanocomposite film for guided tissue regeneration

It has been proposed that localized and controlled delivery of alendronate and tetracycline to periodontal pocket fluids via guided tissue regeneration (GTR) membranes may be a valuable adjunctive treatment for advanced periodontitis. The objectives of this work were to develop a co-loaded, controlled release tetracycline and alendronate nanocomposite plasticized poly(lactic-co-glycolic acid) (PLGA) film that would form a suitable matrix supporting osteoblast proliferation and differentiation. Alendronate release was successfully controlled, with complete suppression of the burst phase of release by intercalation of alendronate anions in magnesium/aluminum layered double hydroxide (LDH) clay nanoparticles and dispersed in the PLGA film matrix. Tetracycline, loaded as free drug into the film together with alendronate-LDH clay complex released more rapidly than alendronate, but showed evidence of intercalation in the LDH clay particles. The dual drug loaded nanocomposite films were biocompatible with osteoblasts and after 5 week incubations, significant increase in alkaline phosphatase activity and bone nodule formation were observed.

Determination of zoledronic acid in human urine and blood plasma using liquid chromatography/electrospray mass spectrometry

A new method for the analysis of 1-hydroxy-2-imidazol-1-yl-phosphonoethyl phosphoric acid (zoledronic acid) in urine and blood samples has been developed. It consists of a derivatisation of the bisphosphonate with trimethylsilyl diazomethane under multiple methylester formation. The formed derivative can, in contrast to the non-derivatised analyte, easily be separated by reversed phase liquid chromatography due to its reduced polarity. Detection is performed by electrospray tandem mass spectrometry. For calibration purposes, a deuterated internal standard has been synthesised in a three-step synthesis starting with d(4)-imidazole. For human urine, the limit of detection (LOD) is 1.2x10(-7) mol/L, limit of quantification (LOQ) is 3.75×10(-7) mol/L in the MRM mode. For human blood plasma, a LOD of 1×10(-7) mol/L and a LOQ of 2.5×10(-7) mol/L were determined. The linear dynamic range comprised 3.5 decades starting at the limit of quantification. The method was successfully applied for the analysis of spiked urine and blood plasma samples as well as samples from two osteoporosis patients.

Study of bisphosphonates by matrix-assisted laser desorption/ionization mass spectrometry--influence of alkali atoms on fragmentation patterns

1-hydroxymethylene-1,1-bisphosphonic acids (or bisphosphonates) are compounds that have interesting pharmacological applications. However, few mass spectrometric investigations have been carried out to determine their fragmentation patterns. Herein, we evaluated different matrices for the study by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) of the formation and fragmentation of the protonated, the cationized (MNa+ and MK+) and the deprotonated bisphosphonates. Some in-source fragmentations were observed both in positive and in negative ion modes. The fragmentation patterns obtained in post-source decay mode are also discussed. In contrast to previous electrospray ionization/multi-stage mass spectrometry (ESI-MSn) studies, some new fragmentation pathways were deduced and the effects of alkali ions on the fragmentation patterns were shown. The results summarized here completed the data previously recorded by ESI-MSn and could be used for the characterization of bisphosphonates as alkali complexes in biological mixtures.

Intra-articular clodronate for the treatment of knee osteoarthritis: dose ranging study vs hyaluronic acid

OBJECTIVE

Bisphosphonates may have a chondroprotective effect in patients with knee OA (KOA), but the results of clinical trials with oral bisphosphonates have been contradictory. In this Phase 2 randomized, partially blind clinical trial, we tested the efficacy of IA clodronate vs HA in patients with primary KOA.

METHODS

One hundred and fifty men or women aged 50-75 years suffering from KOA were randomized to one of five IA therapies: (i) clodronate 0.5 mg one IA injection/week for 4 weeks; (ii) clodronate 1 mg one IA injection/week for 4 weeks; (iii) clodronate 2 mg one IA injection/week for 4 weeks; (iv) clodronate 1 mg two IA injections/week for 2 weeks (clodronate 1 + 1 mg); and (v) HA 20 mg one IA injection/week for 4 weeks.

RESULTS

Visual analogue scores (VASs) for different types of pain and the Lequesne index significantly improved in all treatment groups after the first injection and continued to improve even 2-4 weeks after the last injection without significant difference among the groups. A significant (P = 0.03) linear trend for a dose-response (0.5-2 mg clodronate) relationship was found for active movement VAS pain. Both joint extension and mobility scores improved significantly at all time points in all treatment groups without statistical differences among them.

CONCLUSIONS

This study indicates that IA clodronate provides symptomatic and functional improvements at least as good as those obtained with HA. Trial Registration. Osservatorio Nazionale sulla Sperimentazione Clinica dei Medicinali - Agenzia Italiana del Farmaco. Comitato Etico Azienda Ospedaliera Universitaria Senese number CLIO 22/02 http://oss-sper-clin.agenziafarmaco.it.