Comparative effects of 17% ethylenediaminetetraacetic acid and 9% etidronic acid applied with different irrigant activation techniques on the release of growth factors from dentin: in vitro study.

BACKGROUND: Growth factors embedded in the extracellular matrix of the dentin play an important role in the migration, proliferation, and differentiation of dental pulp stem cells in regenerative endodontics. In regenerative endodontic treatments, the type of irrigation solution used is crucial for the release of growth factors (GFs) from the dentin matrix. This study evaluated the effectiveness of different irrigant activation techniques (IAT) using two different chelating agents, 17% ethylenediaminetetraacetic acid (EDTA) and 9% etidronic acid (HEDP), in terms of their GF release. METHODS: Seventy-two mandibular premolar teeth were prepared to simulate an open apex. The root fragments were irrigated with 20 ml of 1.5% sodium hypochlorite and 20 ml of saline solution. Eight root fragments were randomly separated for the control group, and the remaining 64 fragments were randomly separated into eight groups based on two different chelating agents (17% EDTA and 9% HEDP) and four different IAT ((conventional needle irrigation (CNI), passive ultrasonic irrigation (PUI), sonic activation with EDDY, and XP-endo Finisher (XPF)). TGF-ß1, VEGF-A, BMP-7 and IGF-1 release levels were determined using an ELISA, and statistical analysis was performed using the Kolmogorov-Smirnov test, ANOVA, and the Tukey test (p < .05). RESULTS: Compared to the control group, the experimental groups showed significantly higher GF release when using EDTA or HEDP. Among the activation groups, the EDDY group triggered the highest GF release, and the CNI group triggered the lowest. CONCLUSIONS: IAT with EDTA and HEDP can increase GF release, with EDDY being the most effective IAT method. Using chelating agents with IAT may be beneficial in regenerative endodontic treatments.

Structural Diversity in Antiosteolytic Bisphosphonates: Deciphering Structure-Activity Trends in Ultra Long Controlled Release Phenomena.

Bisphosphonate (BP)-based treatments have been extensively prescribed for bone-related conditions, particularly for osteoporosis. Their low bioavailability creates the need for prescribed dosage increase to reach therapeutic levels but generates a plethora of undesirable side effects. A viable approach to alleviating these issues is to design and exploit controlled release strategies. Herein, the controlled release profiles of 15 structurally characterized BPs (actual drugs and structural analogs) were thoroughly studied from tablets containing three (cellulose, lactose, and silica) or two (cellulose, and silica) excipients in human stomach-simulated pH conditions. The BPs were of two types, alkyl-BPs and amino-BPs. Alkyl-BPs included four derivatives of etidronate (acid, disodium, tetra-sodium, and monopotassium forms), medronic acid, and three analogs of etidronate, in which the -CH3 group was replaced by the moieties -H, -CH2CH2CH3, and -CH2CH2CH2CH2CH3. Amino-BPs included the commercial drugs pamidronate, alendronate, neridronate, and ibandronate, as well as three analog compounds. Release curves were constructed based on data taken from 1H NMR peak integration and were expressed as "% BP release" vs time. The controlled release profiles (initial release rate, plateau value, etc.) were correlated with certain structural features (number of hydrogen and metal-oxygen bonds), showing that the molecular and crystal lattice features of each BP profoundly influence its release characteristics. It was concluded that for all BPs, in general, the initial rate became lower as the total number of lattice interactions increased. For the alkyl-BPs elongation of the alkyl side chain seems to decelerate the release. Amino-BPs, in general, show slower release than the alkyl-BPs. No adverse effects of alkyl- and amino-BP drugs on NIH3T3 cell viability were noted.

Enhanced inhibition of HEDP on SRB-mediated corrosion with D-phenylalanine.

Microbiologically influenced corrosion (MIC) caused by biofilm is a serious problem in many industries. D-amino acids could be a potential strategy to enhance traditional corrosion inhibitors due to their roles in biofilm reduction. However, the synergistic mechanism of D-amino acids and inhibitors remains unknown. In this study, D-Phenylalanine (D-Phe) and 1-hydroxyethane-1,1-diphosphonic acid (HEDP) were selected as the typical D-amino acid and corrosion inhibitor to evaluate their effect on the corrosion caused by Desulfovibrio vulgaris. The combination of HEDP and D-Phe obviously slowed down the corrosion process by 32.25%, decreased the corrosion pit depth and retarded cathodic reaction. SEM and CLSM analysis indicated that D-Phe reduced the content of extracellular protein and thus inhibited the biofilm formation. The molecular mechanism of D-Phe and HEDP on corrosion inhibition was further explored via transcriptome. The combination of HEDP and D-Phe down-regulated the gene expression of peptidoglycan, flagellum, electron transfer, ferredoxin and quorum sensing (QS) molecules, leading to less peptidoglycan synthesis, weaker electron transfer and stronger QS factor inhibition. This work provides a new strategy for improving traditional corrosion inhibitors, retarding MIC and mitigating subsequent water eutrophication.

Beyond Antiresorptive Activity: Risedronate-Based Coordination Complexes To Potentially Treat Osteolytic Metastases.

Coordination of clinically employed bisphosphonate, risedronate (RISE), to bioactive metals, Ca2+, Mg2+, and Zn2+, allowed the formation of bisphosphonate-based coordination complexes (BPCCs). Three RISE-based BPCCs, RISE-Ca, RISE-Mg, and RISE-Zn, were produced, and their structures were elucidated by single crystal X-ray diffraction. Interestingly, the addition of an auxiliary ligand, etidronic acid (HEDP), resulted in the recrystallized protonated form of the ligand, H-RISE. The pH-dependent structural stability of the RISE-based BPCCs was measured by means of dissolution profiles under neutral and acidic simulated physiological conditions (PBS and FaSSGF, respectively). In comparison to RISE (Actonel), the complexes showed a lower equilibrium solubility (∼70-85% in 18-24 h) in PBS, while a higher equilibrium solubility (∼100% in 3 h) in acidic media. The results point to the capacity to release this BP in a pH-dependent manner from the RISE-based BPCCs. Subsequently, the particle size of RISE-Ca was reduced, from 300 µm to ∼350 d.nm, employing the phase inversion temperature (PIT)-nanoemulsion method, resulting in nano-Ca@RISE. Aggregation measurements of nano-Ca@RISE in 1% fetal bovine serum (FBS):H2O was monitored after 24, 48, and 72 h to study the particle size longevity in physiological media, showing that the suspended material has the potential to maintain its particle size over time. Furthermore, binding assays were performed to determine the potential binding of nano-Ca@RISE to the bone, where results show higher binding (∼1.7×) for the material to hydroxyapatite (HA, 30%) when compared to RISE (17%) in 1 d. The cytotoxicity effects of nano-Ca@RISE were compared to those of RISE against the human breast cancer MDA-MB-231 and normal osteoblast-like hFOB 1.19 cell lines by dose-response curves and relative cell viability assays in an in vitro setting. The results demonstrate that nano-Ca@RISE significantly decreases the viability of MDA-MB-231 with high specificity, at concentrations ∼2-3× lower than the ones reported employing other third-generation BPs. This is supported by the fact that when normal osteoblast cells (hFOB 1.19), which are part of the tissue microenvironment at metastatic sites, were treated with nano-Ca@RISE no significant decrease in viability was observed. This study expands on the therapeutic potential of RISE beyond its antiresorptive activity through the design of BPCCs, specifically nano-Ca@RISE, that bind to the bone and degrade in a pH-dependent manner under acidic conditions.

Enhancing the Intracanal Antibacterial Effects of Sodium Hypochlorite with Etidronic Acid or Citric Acid.

INTRODUCTION: This study evaluated the bacterial reduction promoted by root canal preparation using irrigation with sodium hypochlorite (NaOCl) alone, associated with etidronic acid (1-hydroxyethane 1,1-diphosphonic acid [HEDP]) or alternated with citric acid, and after a supplementary agitation step. METHODS: Extracted mandibular premolars were selected and distributed into 3 groups based on anatomically paired micro-computed tomographic analyses. The canals were contaminated with Enterococcus faecalis for 30 days and then subjected to chemomechanical preparation with a reciprocating instrument under irrigation with NaOCl alone, mixed with HEDP (NaOCl/HEDP), or alternated with citric acid (NaOCl/CA). A supplementary agitation step with the XP-endo Finisher was performed in all groups. Intracanal bacteriological samples were taken before (S1) and after preparation (S2) and after the supplementary approach (S3). DNA was extracted from the samples and subjected to quantitative real-time polymerase chain reaction. RESULTS: Intragroup analyses revealed a substantial bacterial reduction from S1 to S2 or S3 in all groups (P < .01). The supplementary agitation resulted in S2-to-S3 bacterial reduction of 6%, 68%, and 80% in the NaOCl, NaOCl/HEDP, and NaOCl/CA groups, respectively. Irrigation with NaOCl alone resulted in 53% and 47% of samples negative for bacteria in S2 and S3, respectively. Corresponding figures for NaOCl/HEDP were 75% and 85%, and 44% and 72% for NaOCl/CA. Intergroup analyses of S2 samples showed that NaOCl/HEDP was significantly more effective than the other 2 in reducing the bacterial levels (P < .05). After the supplementary approach, both NaOCl/HEDP and NaOCl/CA were significantly more effective than NaOCl alone (P < .05), with no significant differences between them (P > .05). CONCLUSIONS: Both the freshly combined NaOCl/HEDP solution and the alternate use of NaOCl and citric acid followed by XP-endo Finisher agitation resulted in significantly higher intracanal bacterial reduction than NaOCl alone.

Impact of agitation/activation strategies on the antibiofilm potential of sodium hypochlorite/etidronate mixture in vitro.

BACKGROUND: To investigate the effect of a rotary agitation method or ultrasonically activated irrigation on the antibiofilm effect of a mixture of sodium hypochlorite (NaOCl) and etidronate (1-hydroxyethylidene-1,1-bisphosphonate, HEBP) using a dual-species biofilm model in root canal system. METHODS: Mature dual-species biofilms of Enterococcus faecalis and Streptococcus gordonii were formed in root canals of mandibular premolars. Teeth were randomly allotted (n = 12) to group 1, XP-endo Finisher (XPF); group 2, ultrasonically activated irrigation (UAI); group 3, syringe-and-needle irrigation (SNI). In all groups, canals were instrumented with a rotary instrument (XP-endo Shaper) prior to irrigant agitation/activation. A mixture containing 2.5% NaOCl and 9% HEBP was used throughout the experiment. Bacterial counts from the canal were determined using qPCR before preparation (S1), after preparation (S2), and after final irrigation agitation/activation (S3). Bacterial viability within the dentinal tubules in the coronal, middle and apical root-thirds was quantified using confocal microscopy after Live/Dead staining. The bacterial counts and viability were compared between groups using one-way ANOVA and post-hoc Tukey's tests. Paired t-test was used to compare the bacterial counts within groups. RESULTS: Instrumentation alone could significantly reduce the microbial counts in all the groups (P < 0.0001). Subsequent agitation/activation resulted in significant microbial reduction only in XPF and UAI (P < 0.05), both of which reduced significantly more microbial counts than SNI (P < 0.05). Live/Dead staining revealed that XPF and UAI showed significantly greater percentage of dead bacteria within the dentinal tubules than SNI in the coronal third (P < 0.05); UAI resulted in the significantly highest percentage of dead bacteria in the middle third (P < 0.05); while there was no significant difference between the groups in the apical third (P > 0.05). CONCLUSIONS: When using the sodium hypochlorite/etidronate mixture for irrigation, final irrigant agitation/activation with XP-endo Finisher or ultrasonic can improve disinfection of the main root canal space and the dentinal tubules in the coronal third, while ultrasonically activated irrigation appears to exhibit better disinfection within dentinal tubules in the middle third.

The cytotoxic effects of various endodontic irrigants on the viability of dental mesenchymal stem cells.

This study aimed to evaluate cytotoxic effects of various irrigation solutions used in regenerative endodontic treatments (RETs) on mesenchymal stem cells, and further examine the long-term effect of hypochlorous acid (HOCl) on the cell viability and alkaline phosphatase (ALP) activity. Stem cells were exposed to various concentrations of NaOCl, EDTA, chlorhexidine (CHX), etidronic acid (HEDP)/NaOCl combination and HOCl. HOCl was tested for its effects on ALP activity up to 21 days. Additionally, cell viability was measured fluorescently using calcein AM. The most cytotoxic irrigant was CHX even with the lowest concentration. NaOCl and HEDP/NaOCl with 1:100 dilution decreased viability to around 40%. HOCl showed the lowest cytotoxicity among all tested irrigants. HOCl also showed no significant reduction in ALP activity compared with the controls. The cytotoxicity of endodontic irrigants was time and concentration dependent. HOCl demonstrated promising results regarding viability and ALP activity, since RETs require host stem cell survival.

Assessment of calciprotein particle formation by AUC of the absorbance change: effect of FYB-931, a novel bisphosphonate compound.

OBJECTIVE: Ectopic calcification such as vascular calcification, involves the formation of calciprotein particle (CPP), that is, colloidal particle of calcium phosphate bound to serum protein. In this study, a novel parameter for CPP formation was introduced, thereby the effect of FYB-931, a bisphosphonate compound was evaluated. METHODS: CPP formation in rat serum was assessed by the area under the curve (AUC) of the change in absorbance over time, and the commonly used T50, as indices. In vivo, the rats were treated with vitamin D3 to induce vascular calcification and then intravenously administered FYB-931 or etidronate thrice weekly for 2 weeks. KEY FINDINGS: In vitro, FYB-931 was the most potent inhibitor of CPP formation and it also inhibited the maximum response of CPP formation at higher concentrations. The AUC of the change in absorbance provided obvious dose-dependency, while T50 did not. FYB-931 dose-dependently prevented aortic calcification in vivo as well as CPP formation ex vivo more potently than etidronate. AUC showed a stronger correlation with the degree of aortic calcification than T50. CONCLUSIONS: The AUC in CPP formation can be an alternative parameter that reflects calcification. Based on the findings, FYB-931 has potential as an anti-calcifying agent.

Effects of heat in the properties of NaOCl alone and mixed with etidronate and alkaline tetrasodium EDTA.

AIM: To assess the free available chlorine concentration (FAC), organic tissue dissolution and smear layer removal capacity of sodium hypochlorite (NaOCl) alone and when mixtured with etidronate (HEDP) and tetrasodium EDTA (Na4 EDTA), and heated to different temperatures. METHODOLOGY: Mixtures at 1 : 1 ratio of 5% NaOCl with distilled water (considered NaOCl alone), 18% HEDP or 10% Na4 EDTA were heated to 25 °C, 37 °C, 48 °C and 60 °C. The FAC in the mixtures was assessed at 5, 10, 20, 30, 60 and 120 min. Samples of bovine muscle tissue (n = 10) were prepared with similar size and weighed before and after 5, 10 and 15 min of immersion in the mixtures heated to the different temperatures to verify organic matter dissolution. The intergroup results were compared statistically using one-way analysis of variance (anova) and intragroup by two-way analysis of variance (anova), both followed by Tukey's multiple-comparison test (α < 0.01). Bovine dentine blocks (n = 10) were analysed by scanning electron microscopy before and after immersion in the mixtures, and the time taken to remove the smear layer from the surfaces of the samples was determined. The Friedman test was used to compare the scores of the same group (α < 0.01), and the Kruskal-Wallis test with Dunn's post hoc was used to compare the different groups (α < 0.01). Saline solution was used as a control in the experiments of tissue dissolution and smear layer removal, RESULTS: Heating NaOCl alone did not affect its FAC. The higher the temperature of the mixtures with the chelators, the lower the FAC. Organic tissue dissolution was improved by increases in temperature of NaOCl alone and its mixture with HEDP (P < 0.01); however, the mixture with Na4 EDTA had no improvement (P > 0.01). Smear layer removal by NaOCl alone was enhanced by heating resulting in lower scores in some samples and became more rapid in the mixtures with the chelators. The saline solution did not promote tissue dissolution nor smear layer removal (P > 0.01). CONCLUSION: In this laboratory study, heating NaOCl alone or when mixed with HEDP improved its capacity to dissolve organic matter and remove the smear layer. However, the mixture with HEDP required frequent refreshment to retain these effects when heated. Due to the acceleration in the reaction between the irrigants, very rapid reductions in the free available chlorine in the mixtures with Na4 EDTA heated to the different temperatures occurred.

Multiple assessment methodologies in determining the antibiofilm actions of sodium hypochlorite mixed with clodronate or etidronate in endodontic irrigation.

This study aimed to use multiple methodologies, including a novel usage of scanning electron microscopy (SEM), to evaluate the antimicrobial actions of sodium hypochlorite (NaOCl) admixed with clodronate or etidronate in root canal irrigation. The study also examined the usefulness of colony counting as a biofilm assessment methodology. Seven day Enterococcus faecalis biofilms were grown on hydroxyapatite discs. The discs were disinfected with 0.26 M clodronate-5% NaOCl, 0.26 M etidronate-5% NaOCl, 5% NaOCl, or treated with phosphate buffered saline (PBS). Assessments were performed using colony counting, SEM and the XTT reduction assay. The XTT assessment used the same groups but with 2.5% NaOCl. For colony counting, bacteria were removed from the discs by vortex mixing, followed by plating. The discs were subsequently fixed for SEM imagining and evaluators scored the SEM micrographs for remaining bacteria. Antibiofilm actions were assessed with the Kruskal-Wallis and Dunn's multiple comparison tests. SEM micrographs and the XTT assay revealed no differences between the NaOCl controls and the clodronate or etidronate mixtures with NaOCl (P > 0.05). It was concluded that the chelator mixtures with NaOCl had antibiofilm actions comparable to NaOCl. Furthermore, vortex mixing incompletely removed biofilm from HA discs in the PBS controls and hence colony counting using E. faecalis biofilms on hydroxyapatite discs could not be used for intergroup comparisons involving PBS. Additionally, colony counting could not be used for comparisons between the NaOCl treatment groups because the removal of bacteria from the substrate by vortex mixing was affected by the irrigant type.

Etidronate down-regulates Toll-like receptor 2 ligand-induced chemokine production by inhibiting MyD88 expression and NF-κB activation.

OBJECTIVE: Pretreatment of J774.1 cells with etidronate, a non-nitrogen-containing bisphosphonate (non-NBP) used as an antibone resorptive drug, was previously reported to inhibit Toll-like receptor (TLR) 2 agonist-induced proinflammatory cytokine production. The present study aimed to examine the effects of etidronate on chemokine production by human monocytic U937 cells incubated with Pam3Cys-Ser-(Lys)4 (Pam3CSK4, a TLR2 ligand) and lipid A (a TLR4 ligand). METHODS: U937 cells were pretreated with or without etidronate, and then incubated with or without Pam3CSK4 or lipid A. Levels of secreted human interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1) in culture supernatants and activation of nuclear factor-κB (NF-κB) p65 were measured by enzyme-linked immunosorbent assay (ELISA). Cytotoxicity was determined by measuring lactate dehydrogenase (LDH) activity in supernatants. Expression of intracellular adhesion molecule (ICAM)-1 and MyD88 was analyzed by flow cytometry and Western blot analysis, respectively. RESULTS: Etidronate down-regulated IL-8 and MCP-1 production and NF-κB p65 activation induced by Pam3CSK4, but not lipid A, in U937 cells. Etidronate also inhibited MyD88 expression in U937 cells incubated with Pam3CSK4. CONCLUSION: Etidronate down-regulates IL-8 and MCP-1 production in U937 cells by inhibiting both the expression of MyD88 and activation of NF-κB p65 in the TLR2, but not TLR4, pathway.

The effect of etidronate on choroidal neovascular activity in patients with pseudoxanthoma elasticum.

AIM: To assess the effect of the bisphosphonate etidronate on choroidal neovascular (CNV) activity in patients with pseudoxanthoma elasticum (PXE). METHODS: This is an ancillary study in a single center, randomized, double-blind placebo-controlled trial (RCT) in which 74 patients with PXE were assigned to either one-year etidronate or placebo treatment. Spectral domain optical coherence tomography (SD-OCT) imaging and color fundus photography were performed every three months for one year and were systematically assessed on signs of CNV activity. RESULTS: In the etidronate group, 11 (30%) of the patients had CNV activity at baseline, compared to 25 (67%) of the patients in the placebo group (P = 0.005). The proportion of eyes with CNV activity during the study ranged from 18-33% in the etidronate group and 42-56% in the placebo group and no significant difference in improvement or worsening of CNV activity was found (P = 0.168). Using a generalized mixed model for repeated measures, there was a protective effect of etidronate in crude analysis (RR 0.86, 95% CI 0.75-0.98) that disappeared when adjusting for baseline CNV activity (RR 0.97, 95% CI 0.84-1.13). CONCLUSION: In this post-hoc RCT analysis we did not observe a protecting or deteriorating effect of etidronate on CNV activity in patients with PXE after adjustment for baseline CNV.

[Basic Studies on the Mechanism, Prevention, and Treatment of Osteonecrosis of the Jaw Induced by Bisphosphonates].

Since the first report in 2003, bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been increasing, without effective clinical strategies. Osteoporosis is common in elderly women, and bisphosphonates (BPs) are typical and widely used anti-osteoporotic or anti-bone-resorptive drugs. BRONJ is now a serious concern in dentistry. As BPs are pyrophosphate analogues and bind strongly to bone hydroxyapatite, and the P-C-P structure of BPs is non-hydrolysable, they accumulate in bones upon repeated administration. During bone-resorption, BPs are taken into osteoclasts and exhibit cytotoxicity, producing a long-lasting anti-bone-resorptive effect. BPs are divided into nitrogen-containing BPs (N-BPs) and non-nitrogen-containing BPs (non-N-BPs). N-BPs have far stronger anti-bone-resorptive effects than non-N-BPs, and BRONJ is caused by N-BPs. Our murine experiments have revealed the following. N-BPs, but not non-N-BPs, exhibit direct and potent inflammatory/necrotic effects on soft-tissues. These effects are augmented by lipopolysaccharide (the inflammatory component of bacterial cell-walls) and the accumulation of N-BPs in jawbones is augmented by inflammation. N-BPs are taken into soft-tissue cells via phosphate-transporters, while the non-N-BPs etidronate and clodronate inhibit this transportation. Etidronate, but not clodronate, has the effect of expelling N-BPs that have accumulated in bones. Moreover, etidronate and clodronate each have an analgesic effect, while clodronate has an anti-inflammatory effect via inhibition of phosphate-transporters. These findings suggest that BRONJ may be induced by phosphate-transporter-mediated and infection-promoted mechanisms, and that etidronate and clodronate may be useful for preventing and treating BRONJ. Our clinical trials support etidronate being useful for treating BRONJ, although additional clinical trials of etidronate and clodronate are needed.

Novel bisphosphonate compound FYB-931 preferentially inhibits aortic calcification in vitamin D3-treated rats.

In patients with chronic kidney disease (CKD) or those undergoing hemodialysis, pathological calcific deposition known as ectopic calcification occurs in soft tissue, resulting in a life-threatening disorder. A potent and effective inhibitor of ectopic calcification is eagerly expected. In the current study, the effects of FYB-931, a novel bisphosphonate compound synthesized for the prevention of ectopic calcification, were compared with those of etidronate using both in vitro and in vivo models. In vitro, FYB-931 inhibited calcification of human aortic smooth muscle cells induced by high phosphate medium in a concentration-dependent manner, and the effect was slightly more potent than that of etidronate. In vivo, rats were administered with three subcutaneous injections of vitamin D3 to induce vascular calcification, and were given FYB-931 (1.5, 5, or 10 mg/kg) or etidronate (9, 30, or 60 mg/kg) orally once daily for 14 days. The increased aortic phosphorus content as an index of vascular calcification was inhibited by both FYB-931 and etidronate in a dose-dependent manner; however, FYB-931 was 10 times more potent than etidronate. FYB-931 inhibited serum tartrate-resistant acid phosphatase (TRACP) activity as a bone resorption marker 5.2 times more potently than etidronate. FYB-931, but not etidronate, significantly decreased serum phosphorus levels. The preferential inhibition of aortic calcification by FYB-931 suggested that possible additional effect including a decline in serum phosphorus may lead to an advantage in terms of its efficacy.

First-in-Human Phase I Study of MBC-11, a Novel Bone-Targeted Cytarabine-Etidronate Conjugate in Patients with Cancer-Induced Bone Disease.

LESSONS LEARNED: Results are consistent with MBC-11 targeting and treating cancer-induced bone lesions by concentrating cytarabine and etidronate at the site of disease.MBC-11 was well tolerated, with an maximum tolerated dose of 5 mg/kg per day and myelosuppression as the principal toxicity.Treatment significantly reduced cancer cell activity in over half of bone lesions detected at baseline.MBC-11 pharmacokinetic and pharmacodynamic parameters are consistent with the novel drug design goals, and encouraging results warrant further clinical development. BACKGROUND: MBC-11 is a first-in-class conjugate of the bone-targeting bisphosphonate etidronate covalently linked to the antimetabolite cytarabine (araC). This first-in-human phase I dose escalation study assessed safety, tolerability, maximum tolerated dose (MTD), plasma pharmacokinetics, bone turnover, tumor biomarkers, and bone lesion activity by fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) imaging. METHODS: Fifteen patients with advanced solid cancers and cancer-induced bone disease (CIBD) were treated with 0.5-10 mg/kg per day of MBC-11 administered daily for 5 days of every 4 weeks for up to four cycles. RESULTS: Grade 1-2 myelosuppression, involving all lineages, was the principal toxicity. Two of three patients treated with 10 mg/kg experienced dose-limiting grade 4 neutropenia and thrombocytopenia (adverse event [AE] duration ≤5 days); the MTD was 5 mg/kg. Four of five patients with pretreatment elevations of the bone resorption marker TRAP5b (tartrate resistant acid phosphatase-5b) had persistent decrements. Six of 13 patients who reported baseline pain noted a reduction after MBC-11. 18F-FDG-PET/CT imaging demonstrated partial metabolic responses in three patients and stable metabolic responses in three other patients. SUVmax (standard unit of emission normalized to total uptake) was reduced by at least 25% in 110 (52%) of 211 bone lesions. Significant activity was noted across all doses, and myelosuppression increased with dose. CONCLUSION: At MBC-11 doses that were well tolerated, substantial reductions in metabolic activity of bone-associated cancer cells provide a foundation for further disease-directed efficacy studies.

Influence of dentine debris and organic tissue on the properties of sodium hypochlorite solutions.

AIM: To determine the free available chlorine of 2.5% sodium hypochlorite (NaOCl) alone and combined with 9% etidronic acid (HEDP) in the presence of inhibitors, organic tissue and organic tissue plus dentine debris; to evaluate the influence of dentine debris on the tissue-dissolving capacity of both NaOCl solutions; and to determine the antimicrobial action of these solutions when in contact with organic tissue and organic tissue plus dentine debris. METHODOLOGY: The available chlorine of the solutions over time in the absence and presence of the inhibitors was measured using a titration method. The organic tissue dissolution by the solutions alone and in the presence of dentine powder was evaluated by weighing bovine tissue specimens before and after exposure to the solutions for 3 and 10 min. For the antimicrobial activity, biofilms of Enterococcus faecalis were exposed to the solutions for 3 min in the absence and presence of organic tissue and organic tissue + dentine debris. The biovolume and percentage of damaged membrane cells of the biofilm were measured by means of confocal microscopy and the live/dead technique. Nonparametric tests were used to determine statistical differences (P < 0.05). RESULTS: Both inhibitors consumed the free available chlorine of the solutions over time. The presence of dentine debris significantly reduced the tissue dissolution capacity of the NaOCl solutions (P < 0.05). The percentages of biovolume reduction were not affected by the presence of the inhibitors in the two NaOCl solutions, whereas the percentage of damaged membrane cells was significantly reduced (P < 0.001). Overall, a similar behaviour was observed in the NaOCl and NaOCl/HEDP groups. CONCLUSIONS: The presence of organic tissue and organic tissue + dentine debris favoured rapid consumption of the free chlorine of NaOCl and NaOCl/HEDP. This resulted in a decreased ability to dissolve organic tissue without affecting the short-term antimicrobial activity.

Pretreatment-Etidronate Alleviates CoCl2 Induced-SH-SY5Y Cell Apoptosis via Decreased HIF-1α and TRPC5 Channel Proteins.

Chronic hypoxic damage is one of the most common pathogenic factors that can cause neurodegenerative disorder in most cases. Etidronate (Eti) is one of the best-known earlier-generations of bisphosphonate derivatives for the treatment of bone-loss related diseases. Building on the preceding study of our laboratory, we found that Eti showed neuroprotective effects against 2-vessel occlusion induced vascular dementia (VD) in rats. Therefore, in this study, we attempted to elucidate the mechanism of action, which Eti protected cells from chronic hypoxic damage caused by CoCl2 in SH-SY5Y cells in vitro. Our data showed that the pretreatment with 100 µM Eti partially improved hypoxic damage in cell viability and reduced the hypoxia-inducible factor-1α (HIF-1α) expression, which indicated chronic hypoxic level. Furthermore, the protein expression of TRPC5 channel and its mediated intracellular calcium ion concentration ([Ca2+]i) were decreased. In addition, the apoptosis-related proteins caspase-9, and caspase-3 as well as calcium/calmodulin-dependent protein kinase II (CaMK-II) were down-regulated after treatment with Eti. In conclusion, Eti shows neuroprotective effects on SH-SY5Y cells injured by CoCl2 through resisting apoptosis caused by calcium influx, which may be related to the inhibition of HIF-1α protein and the decreased TRPC5 channel protein.

Etidronate attenuates tactile allodynia by spinal ATP release inhibition in mice with partial sciatic nerve ligation.

Etidronate is widely used as a therapeutic agent for osteoporosis. We have recently shown that intrathecal administration of etidronate into mice produces an analgesic effect against the capsaicin-induced nociceptive behavior. However, the effect of etidronate on neuropathic pain at the spinal level remains unknown. Therefore, we examined whether etidronate attenuates pain after partial sciatic nerve ligation (PSNL). We evaluated tactile allodynia 7 days after PSNL by measuring paw withdrawal with the von Frey filament test. The mRNA and protein levels of SLC17A9 in the ipsilateral lumbar dorsal spinal cord of PSNL-operated mice were determined using real-time PCR and western blotting, respectively. PSNL-induced tactile allodynia was attenuated by oral and intrathecal administration of etidronate, with maximum efficiency at 90 and 60 min after injection, respectively. The anti-allodynic effect of intrathecally administered etidronate was completely inhibited by an intrathecal administration of adenosine triphosphate (ATP). The solute carrier family, SLC17, mediates the transport of pain transmitters, like ATP and glutamate. Indeed, we detected several members of the SLC17 family in the mouse dorsal lumbar spinal cord. Among the detected mRNAs, only Slc17a9, encoding for neuronal vesicular ATP transporter, was significantly increased upon PSNL. SLC17A9 protein levels were also significantly increased. In mice subjected to PSNL, SLC17A9 was present in neurons and microglia, but not in astrocytes of the lumbar superficial dorsal horn. Collectively, our results suggest that etidronate produces its anti-allodynic effects by inhibiting SLC17A9-dependent exocytotic ATP release from the dorsal horn in mice subjected to PSNL.

Etidronate protects chronic ocular hypertension induced retinal oxidative stress and promotes retinal ganglion cells growth through IGF-1 signaling pathway.

Glaucoma is a common heterogeneous eye disorder that may lead to irreversible blindness. In the present study, we examined whether etidronate, a member of bisphosphonates, may have neuroprotective effects in in vivo and in vitro rat model of glaucoma. In an in vivo setting, chronic ocular hypertension (COH) was induced in adult rat retina. We discovered that systemic injection of etidronate reduced COH-induced retinal oxidative stress, including caspase-3 activity and MDA level, as well as promoted retinal ganglion cell survival. In an in vitro setting, neonatal retinal ganglion cell was incubated with etidronate. We found etidronate incubation promoted neurite growth, upregulated IGF-1 and p-IGF-1R protein expressions in retinal ganglion cell. In addition, application of a selective IGF-1R antagonist effectively blocked the pro-neuronal effect of etidronate on retinal ganglion cell growth, and reduced p-IGF-1R protein expression. Thus, our results demonstrated that etidronate might reduce retinal oxidative stress and promote retinal neuronal growth through IGF-1 signaling pathway. Future work may define its clinical feasibility to treating human patients with glaucoma.

Influence of inhibitors on the adhesion of SRB to the stainless steel in circulating cooling water.

Influence of the surface characteristics of three stainless steels (SS304, 316L and 317) and presence of scale inhibitors on adhesion kinetics of sulfate reducing bacteria (SRB) in circulating cooling water, were investigated by evaluating surface free energy, adhesion kinetic constants in a parallel plate flow chamber. Results show that the surface free energy values of SS317, SS316L and SS304 are -31.69, -24.18 and -13.92 mJ m-2, respectively. SS317 surface had higher surface hydrophobicity than SS316L and SS304. In the process of bacteria cells adhesion onto SS surfaces, electrostatic interaction for SS is slightly more than hydrophobic interaction. The number of adhering bacteria and the adhesion kinetic constants are different on the three types of stainless steel. The adhesion kinetic constants for SS317 and 316L are greater than that for SS304, which are 0.0354, 0.0282 and 0.0190 min-1, respectively. Scale inhibitors of hydrosy ethyl fork phosphonic acid (HEDP) and phosphono butane-1, 2, 4-tricarboxylic acid (PBTCA) have a certain influence on the initial adhesion of bacteria cell and adhesion kinetics constants are reduced in the presence of HEDP and PBTCA.