Resorption Surfaces Research Articles

Geochemical and isotopic constraints on the role of juvenile crust and magma mixing in the UDMA magmatism, Iran: evidence from mafic microgranular enclaves and cogenetic granitoids in the Zafarghand igneous complex

The Zafarghand Igneous Complex is composed of granite, granodiorite, diorite, and gabbro that contain many mafic microgranular enclaves. This complex was emplaced during the late Oligocene (24.6 Ma) to form part of the Urumieh–Dokhtar magmatic arc of Central Iran. The enclaves have spheroidal to elongated/lenticular shapes and are quenched mafic melts in felsic host magma as evidenced by fine-grained sinuous margins and (or) locally transitional and diffuse contacts with the host rocks, as well as having disequilibrium textures. These textures including oscillatory zoning with resorption surfaces on plagioclase, feldspar megacrysts with poikilitic and anti-rapakivi textures, mafic clots, acicular apatites, and small lath-shaped plagioclase in larger plagioclase crystals all indicate that the enclaves crystallized from mafic magma that was injected into and mixing/mingling with the host felsic magma. The studied rocks have calc-alkaline, metaluminous compositions, with an arc affinity. They are enriched in large ion lithophile elements, light rare-earth elements, and depleted in high field strength elements with significant negative Eu anomalies. The Sr–Nd isotopic data for all of the samples are similar and display ISr = 0.705123–0.705950 and eNd (24.6 Ma) = − 1.04–1.03 with TDM ~ 0.9–1.1 Ga. The host granites and enclaves are of mixed/mingled origin and most probably formed by the interaction between the juvenile lower crust with a basaltic composition and old lower or middle continental crust as a major component and lithospheric mantle as a minor component; this was followed by fractional crystallization and possibly minor crustal assimilation. The source seems to be comprised of about 90–80% of the basaltic magma and about 10–20% of lower/middle-crust-derived magma. Geochemical characteristics indicate that the intrusion of these rocks from a subduction zone setting below the Central Iran micro-continent was related to an active continental margin, although was transitional to a transtensional setting possibly due oblique convergence to slab rollback or break-off.

Fracture-Targeted Delivery of β-Catenin Agonists via Peptide-Functionalized Nanoparticles Augments Fracture Healing.

Despite several decades of progress, bone-specific drug delivery is still a major challenge. Current bone-acting drugs require high-dose systemic administration which decreases therapeutic efficacy and increases off-target tissue effects. Here, a bone-targeted nanoparticle (NP) delivery system for a β-catenin agonist, 3-amino-6-(4-((4-methylpiperazin-1-yl)sulfonyl)phenyl)-N-(pyridin-3-yl)pyrazine-2-carboxamide, a glycogen synthase kinase 3 beta (GSK-3β) inhibitor, was developed to enhance fracture healing. The GSK-3β inhibitor loading capacity was found to be 15 wt % within highly stable poly(styrene-alt-maleic anhydride)-b-poly(styrene) NPs, resulting in ∼50 nm particles with ∼ -30 mV surface charge. A peptide with high affinity for tartrate-resistant acid phosphatase (TRAP), a protein deposited by osteoclasts on bone resorptive surfaces, was introduced to the NP corona to achieve preferential delivery to fractured bone. Targeted NPs showed improved pharmacokinetic profiles with greater accumulation at fractured bone, accompanied by significant uptake in regenerative cell types (mesenchymal stem cells (MSCs) and osteoblasts). MSCs treated with drug-loaded NPs in vitro exhibited 2-fold greater β-catenin signaling than free drug that was sustained for 5 days. To verify similar activity in vivo, TOPGAL reporter mice bearing fractures were treated with targeted GSK-3β inhibitor-loaded NPs. Robust β-galactosidase activity was observed in fracture callus and periosteum treated with targeted carriers versus controls, indicating potent β-catenin activation during the healing process. Enhanced bone formation and microarchitecture were observed in mice treated with GSK-3β inhibitor delivered via TRAP-binding peptide-targeted NPs. Specifically, increased bone bridging, ∼4-fold greater torsional rigidity, and greater volumes of newly deposited bone were observed 28 days after treatment, indicating expedited fracture healing.

Histopathological Observation of Three Types of Root Resorption Surface in Maxillary Primary Incisors

ì „ì‹ ì  또는 êµ­ì†Œì  요소에 의하여 ìœ ì¹˜ 치근이 ë³‘ì ìœ¼ë¡œ í¡ìˆ˜ë ìˆ˜ 있으며 치아 우식증이나 외상 등으로 염증성 치근 흡수가 ë°œìƒí• ìˆ˜ 있다. ìœ ì¹˜ì˜ ë³‘ì  치근 흡수면은 ìƒë¦¬ì ì¸ 치근 흡수와 ë¹„êµí• ë•Œ 흡수면의 세포와 흡수와의 형태 등의 흡수 양상이 다르다. 이 연구는 ìƒë¦¬ì  치근 흡수, 외상, 염증성 치근 흡수면의 형태 및 ì¸ì ‘í•œ 세포를 ì£¼ì‚¬ì „ìží˜„ë¯¸ê²½ê³¼ 광학현미경으로 관찰하였다. ìƒë¦¬ì  치근 흡수면의 흡수소와는 원형과 íƒ€ì›í˜•ì´ê³ ë¹„êµì  ìž‘ê³ ê· ì¼í•˜ì˜€ë‹¤. 외상으로 인한 치근 흡수면과 염증성 치근 흡수면의 흡수소와는 ìƒë¦¬ì  치근 흡수면의 흡수소와에 비해 다각형이며 í¬ê³ ë¶ˆê·œì¹™í•˜ì˜€ë‹¤. ìƒë¦¬ì  치근 흡수면과 외상으로 인한 치근 흡수면, 염증성 치근 흡수면에서 다핵거대세포와 단핵세포가 관찰되었으며 염증성 치근 흡수면에서는 간엽세포 및 염증세포가 많이 분포되어 있었다. ìƒë¦¬ì  치근 흡수면과 외상으로 인한 치근 흡수면에서는 흡수 표면에 ë°±ì• ì§ˆì–‘ 조직이 침착되었으나, 염증성 치근 흡수면에서는 관찰되지 않았다.

Bone turnover is altered in transgenic rats overexpressing the P2Y2 purinergic receptor.

It is now widely recognized that purinergic signaling plays an important role in the regulation of bone remodeling. One receptor subtype, which has been suggested to be involved in this regulation, is the P2Y2 receptor (P2Y2R). In the present study, we investigated the effect of P2Y2R overexpression on bone status and bone cell function using a transgenic rat. Three-month-old female transgenic Sprague Dawley rats overexpressing P2Y2R (P2Y2R-Tg) showed higher bone strength of the femoral neck. Histomorphometry showed increase in resorptive surfaces and reduction in mineralizing surfaces. Both mineral apposition rate and thickness of the endocortical osteoid layer were higher in the P2Y2R-Tg rats. μCT analysis showed reduced trabecular thickness and structural model index in P2Y2R-Tg rats. Femoral length was increased in the P2Y2R-Tg rats compared to Wt rats. In vitro, there was an increased formation of osteoclasts, but no change in total resorption in cultures from P2Y2R-Tg rats. The formation of mineralized nodules was significantly reduced in the osteoblastic cultures from P2Y2R-Tg rats. In conclusion, our study suggests that P2Y2R is involved in regulation of bone turnover, due to the effects on both osteoblasts and osteoclasts and that these effects might be relevant in the regulation of bone growth.

Comparative Evaluation of Efficacy of Three Different Storage Media in Maintaining the Viability of Periodontal Ligament Cells: An In Vitro Study

Introduction: Dental trauma is the most common injury which occurs in oro-facial region. Traumatic dental injuries are often seen among injuries to the face. Among them, tooth avulsion (0.5%-16%) is a complex traumatic injury characterized by the rupture of the neurovascular bundle and periodontal ligament (PDL) exposing the tooth to the outer environment. It occurs most often in the age group of 7-10 years, when the alveolar bone is resilient and offers minimal resistance to extrusive forces. Avulsion is a potential threat to the vitality of Periodontal ligament cells which are essential for the healing of replanted avulsed teeth. Hence management protocols should include management of the pulp and the periodontal ligament cells in the long-term survival and prognosis of avulsed teeth.2 The types of healing that takes place after the avulsion injury are as follows: 1.Favorable healing: a. Healing with a normal periodontal ligament (without root resorption) b. Healing with surface resorption (repair-related resorption) 2.Unfavorable healing: a. Healing with ankylosis (replacement). b. Healing with inflammatory resorption (infection related resorption).3 Two of the most critical factors affecting the prognosis of an avulsed tooth after replantation are extra oral dry time and the storage medium in which the tooth is placed.4As replantation of avulsed teeth occurs more frequently between 1 and 4 hours after avulsion, degeneration of cemental periodontal ligament fibers is a common event and the presence of necrotic Periodontal ligament remnants on root surface stimulates the occurrence of inflammatory root resorption, which is the major cause of loss of replanted teeth.5Secondly, storage or transport medium to support cell viability is more important than the extra oral Introduction: An ideal storage medium should be one that is capable of preserving the viability, mitogenicity and clonogenic capacity of the damaged Periodontal ligament cells to facilitate proliferation of these cells over the denuded root surface, thereby preventing further root resorption.Aim: The aim of this study is to evaluate the effectiveness of Casein phosphopeptide amorphous calcium phosphate as a storage media for avulsed tooth in maintaining periodontal ligament cell viability in comparison with Hank’s Balanced Salt Solution and Oral Rehydration Solution.Materials and Methods: Forty freshly extracted human premolar teeth with normal periodontium and closed apices were taken. Forty teeth were randomly assigned into five experimental groups. It was then incubated for 30 minutes in falcon tubes with 2.5 ml solution of 0.2 mg/ml of collagenase II and 2.4 mg/ml solution of dispase grade II in phosphate buffered saline. After incubation, 50 μl of fetal bovine serum was added to each tube with the help of micropipette. Cells were labelled with 0.4% trypan blue for determination of viability. The number of viable cells in a grid of Neubauer’s chamber were counted under a light microscope at 40X magnification.Results: Results were analysed using Kruskul-Wallis test and Mann-Whitney U test.Conclusion: GC Tooth Mousse, Hanks balanced salt solution and Oral rehydration solution can be used as storage medium. GC Tooth Mousse is better than Hanks balanced salt solution and Oral rehydration solution as a storage medium.

Low-intensity laser therapy efficacy evaluation in mice subjected to acute arthritis condition

Acute arthritis is an inflammation that affects many joints. The principal treatment options comprise drugs (corticosteroids), invasive and painful surgery. The objective of this study was to evaluate the efficacy of low intensity laser therapy (LILT), a non-invasive treatment, in a murine model of acute inflammation model. 48 mice received a synovial injection of Zymosan A into one knee. Mice were treated with LILT by three different wavelengths, either as a single (S) or dual (D) application immediately after the injury or after 24h following initiation of an inflammatory response. The histological analysis aimed at identifying inflammatory infiltrate and the structure of the articular surfaces as an indicator of a long-term damage due to inflammation. Statistical analysis (Kruskal-Wallis test), did not allow to reject the null hypothesis. However, LILT promoted histological alterations in some treatment groups. Histological evidence (Median and confidence interval) of anti-inflammatory effects was especially noticeable in knees of mice irradiated with lasers emitting moderate intensity and continuous 660nm (S=18.5 (11.4; 27.6); D=16.0 (6.93; 27.0)) and high intensity and pulsed 905nm (S=17.5 (10.2; 24.79), with decrease of the resorbed region. However, the 905nm pulsed laser was responsible for exacerbation of inflammation for multiple LILT sessions with a short delay (D=45.0 (22.84; 63.83)), tending to aggravate the resorption of the articular surface (p<0.05). LILT showed signs of an anti-inflammatory effect when applied once, but promoted increased resorptive area when used for two sessions, indicating the importance of a controlled LILT protocol to reach therapeutic effects.

Development of cyclic shedding teeth from semi-shedding teeth: the inner dental arcade of the stem osteichthyan Lophosteus.

The numerous cushion-shaped tooth-bearing plates attributed to the stem group osteichthyan Lophosteus superbus, which are argued here to represent an early form of the osteichthyan inner dental arcade, display a previously unknown and presumably primitive mode of tooth shedding by basal hard tissue resorption. They carry regularly spaced, recumbent, gently recurved teeth arranged in transverse tooth files that diverge towards the lingual margin of the cushion. Three-dimensional reconstruction from propagation phase-contrast synchrotron microtomography (PPC-SRµCT) reveals remnants of the first-generation teeth embedded in the basal plate, a feature never previously observed in any taxon. These teeth were shed by semi-basal resorption with the periphery of their bases retained as dentine rings. The rings are highly overlapped, which evidences tooth shedding prior to adding the next first-generation tooth at the growing edge of the plate. The first generation of teeth is thus diachronous. Successor teeth at the same sites underwent cyclical replacing and shedding through basal resorption, producing stacks of buried resorption surfaces separated by bone of attachment. The number and spatial arrangement of resorption surfaces elucidates that basal resorption of replacement teeth had taken place at the older tooth sites before the addition of the youngest first-generation teeth at the lingual margin. Thus, the replacement tooth buds cannot have been generated by a single permanent dental lamina at the lingual edge of the tooth cushion, but must have arisen either from successional dental laminae associated with the individual predecessor teeth, or directly from the dental epithelium of these teeth. The virtual histological dissection of these Late Silurian microfossils broadens our understanding of the development of the gnathostome dental systems and the acquisition of the osteichthyan-type of tooth replacement.

Correlation of Periodontal Disease With Inflammatory Arthritis in the Time Before Modern Medical Intervention.

Controversy exists regarding possible correlation of periodontal disease with rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Confounding factors may relate to stringency of inflammatory disease diagnosis and the effect of therapeutic intervention for RA on periodontal disease. These factors are investigated in this study. Forty-five individuals with documented RA (n = 15), spondyloarthropathy (n = 15), and calcium pyrophosphate deposition disease (CPPD) (n = 15), from the Hamann-Todd collection of human skeletons compiled from 1912 to 1938, and 15 individuals contemporarily incorporated in the collection were examined for tooth loss, cavity occurrence, average and maximum lingual and buccal depth of space between tooth and bone, periosteal reaction, serpentine bone resorption, abscess formation, and root penetration of the bone surface and analyzed by analysis of variance. Tooth loss was common, but actual number of teeth lost, cavity occurrence, average and maximum lingual and buccal depth of space between tooth and bone, periosteal reaction, serpentine grooving surrounding teeth (considered a sign of inflammation), abscess formation, and root exposure (penetration of bone surface) were indistinguishable among controls and individuals with RA, spondyloarthropathy, and CPPD. Although many factors can affect periodontal disease, presence of inflammatory arthritis does not appear to be one of them. The implication is that dental disease was common in the general population and not necessarily associated with arthritis, at least before the advent of modern rheumatologic medications. As specific diagnosis did not affect prevalence, perhaps current prevalence controversy may relate to current intervention, a subject for further study.

Hepatic Osteodystrophy: The Mechanism of Bone Loss in Hepatocellular Disease and the Effects of Pamidronate Treatment

OBJECTIVES:The present study was designed to evaluate the bone phenotypes and mechanisms involved in bone disorders associated with hepatic osteodystrophy. Hepatocellular disease was induced by carbon tetrachloride (CCl4). In addition, the effects of disodium pamidronate on bone tissue were evaluated.METHODS:The study included 4 groups of 15 mice: a) C = mice subjected to vehicle injections; b) C+P = mice subjected to vehicle and pamidronate injections; c) CCl4+V = mice subjected to CCl4 and vehicle injections; and d) CCl4+P = mice subjected to CCl4 and pamidronate injections. CCl4 or vehicle was administered for 8 weeks, while pamidronate or vehicle was injected at the end of the fourth week. Bone histomorphometry and biomechanical analysis were performed in tibiae, while femora were used for micro-computed tomography and gene expression.RESULTS:CCl4 mice exhibited decreased bone volume/trabecular volume and trabecular numbers, as well as increased trabecular separation, as determined by bone histomorphometry and micro-computed tomography, but these changes were not detected in the group treated with pamidronate. CCl4 mice showed increased numbers of osteoclasts and resorption surface. High serum levels of receptor activator of nuclear factor-κB ligand and the increased expression of tartrate-resistant acid phosphatase in the bones of CCl4 mice supported the enhancement of bone resorption in these mice.CONCLUSION:Taken together, these results suggest that bone resorption is the main mechanism of bone loss in chronic hepatocellular disease in mice.

Cytokines Behavior in Multiple Myeloma Patients during Zoledronic Acid Treatment

Objective: Multiple Myeloma (MM) is characterized by uncoupling of bone resorption from bone formation which leads to the predominance of resorption. Bisphosphonates are chemical compounds that selectively concentrate at the interface of the active osteoclasts and the bone resorption surface where they inhibit osteoclast activity. Aim of this study was to describe cytokines behaviour in MM and to evaluate whether zoledronic acid could have an in vivo anti-angiogenic property in MM as observed in solid tumours.Methods: Serum samples from 29 (16 males and 13 females) consecutive MM patients with lytic bone lesions treated with 4 mg of zoledronic acid were tested for platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), tumor necrosis factor (TNF α) and insulin growth factor (IGF-I). Basal cytokine levels were compared with the values observed after 1, 2, 7 and 21 days of treatment, using the Wilcoxon’s test for nonparametric-dependent continuous variables.Results: A significant increase in IL-6 and TNF α was observed on days 1 and 2. As for VEGF, the levels of this cytokine did not change significantly from basal values during the entire period of observation except for a significant increase day 7 (P=0.0005). Moreover, PDGF significantly decreased (P=0.005) after 2 days from zoledronic acid infusion.Conclusions: From this study appears that in MM, treatment with zoledronic acid induces a transient reduction in PDGF according with previous studies in solid cancer, while the increase of IL-6 and VEGF could be related through a paracrine mechanism. The anti-myeloma effect of this drug could be driven through this mechanism.

Unprotected autogenous bone block grafts in anterior maxilla: Resorption rates and clinical outcomes

Background/Aim. The use of autogenous bone grafts for augmentation of the resorbed alveolar ridge is still considered the gold standard in implant dentistry. The aim of this study was to analyze the resorption rate of autogenous bone block grafts from the retromolar region placed in the frontal segment of the upper jaw unprotected by barrier membranes, to assess the stability of implants placed into the grafted bone, as well as to monitor its changes during the healing period. Methods. The study included 18 patients with a total of 20 grafted sites. The residual alveolar ridge was measured before and after the augmentation and prior to implant placement. All implants were restored with provisional crowns within 48 hours after the placement. Implant stability was assessed using resonance frequency analysis. Results. The average period from ridge augmentation to reentry was 5.4 months (range 4?6 months). At reentry the healed alveolar ridge had a mean width of 6.1 ? 1.27 mm. The mean calculated width gain was 3.04 ? 1.22 mm. The overall surface resorption of block grafts was 0.68 ? 0.69 mm (18.85%). At the time of implant placement the mean value of implant stability quotient (ISQ) was 71.25 ? 5.77. The lowest ISQ values were noted after three weeks of healing, followed by a gradual increase until week 12. After 12 weeks implants showed significantly higher ISQ values compared to primary stability (p &lt; 0.05 Wilcoxon signed ranks test). During the 3-years followup period no cases of implant loss were recorded. Conclusion. Despite a significant resorption of bone grafts, it was possible to place implants in all the cases and to use the immediate loading protocol without affecting implant survival rate.

Low‑molecular weight fucoidan inhibits the differentiation of osteoclasts and reduces osteoporosis in ovariectomized rats.

Fucoidan is a type of sulfated polysaccharide isolated from seaweed. The present study used ovariectomized Sprague‑Dawley rats, which were treated with fucoidan. The effects of fucoidan on bone metabolism, density and microarchitecture were assessed using micro‑computed tomography (CT), histomorphometric analysis, biochemical markers of bone metabolism (Serum procollagen typeI N propeptide and C‑terminal telopeptide‑1) and tests of mechanical competence of the femur. In addition, the effects of low‑molecular weight fucoidan (LMWF) on invitro cultured osteoclasts were examined, in order to determine the mechanisms underlying LMWF‑induced osteoclastic inhibition. In ovariectomized rats, LMWF increased femoral bone density. Micro‑CT scan also revealed that LMWF prevented microarchitectural deterioration and histomorphometric analysis determined that LMWF increased trabecular bone number and reduced the surface of bone resorption. In addition, LMWF reduced the high bone turnover rate, and improved the mechanical properties of the femur in ovariectomized rats. Invitro experiments revealed that LMWF inhibited the receptor activator of nuclear factor κB ligand (RANKL) and macrophage colony‑stimulating factor‑induced differentiation of RAW264.7cells into tartrate‑resistant acid phosphatase (TRAP)‑positive osteoclasts, and reduced the bone resorption surface of the osteoclasts. Reverse transcription‑quantitative polymerase chain reaction demonstrated that LMWF inhibited mRNA expression of TRAP, matrix metallopeptidase‑9, nuclear activator of activated T‑cells1, and osteoclast‑associated immunoglobulin‑like receptor, which are components of the signaling pathway for osteoclast differentiation. LMWF had no effect on RANK mRNA expression. In conclusion, the present study confirmed that LMWF inhibited osteoclast differentiation and bone resorption, and may be a potential treatment for osteoporosis in ovariectomized rats.

Origin of the Eocene porphyries and mafic microgranular enclaves from the Beiya porphyry Au polymetallic deposit, western Yunnan, China: Implications for magma mixing/mingling and mineralization

The origin of magmas with high H2O, S and metals that are linked to porphyry economic mineralization in continental collisional belts is controversial. In this paper, we studied the host porphyries and associated microgranular enclaves (MMEs) including gabbroic enclaves and dioritic enclaves from the large Beiya porphyry Au deposit in Jinshajiang-Ailaoshan mineralization belt, which provide first hand evidence of crust–mantle hybridization in the formation of fertile magma for porphyry deposit. Zircon LA-ICPMS U–Pb ages indicate coeval formation for the MMEs and the felsic porphyries in Eocene time (~36Ma). The MMEs show spheroidal shapes, acicular apatites, and oscillatory zoning with repeated resorption surfaces in plagioclases, which suggest that the MMEs are globules of a more mafic magma that was injected into and mingled with the host felsic magma. One gabbroic enclave sample exhibits high MgO (5.6wt.%), high TiO2 (1.7wt.%), enriched in large-ion lithophile element (LILE) and depleted in high field strength element (HFSE), with negative Nb, Ta and Ti anomalies. This indicates that the gabbroic enclave is similar to those of the coeval potassic mafic rocks in the Western Yunnan, which originated from the enriched mantle metasomatized by the slab-derived fluids. The dioritic enclave exhibit both potassic and adakitic-like features, and are characterized by high contents of MgO (4.4–4.9wt.%), K2O (6.4–7.4wt.%), and compatible trace elements (e.g. Ni: 115–142ppm; Cr: 214–291ppm), as well as by high Sr/Y ratios. The dioritic enclave samples yield εHf (t) values (−1.9 to +3.6) similar to those of the host porphyries. Petrographic, elemental, and isotopic evidence suggests that the Beiya dioritic enclave were formed by mixing between potassic mafic and adakitc-like melts, derived from metasomatized lithospheric mantle and lower crust, respectively. In contrast, the Beiya host porphyries are characterized by high SiO2 (66.9–71.9wt.%) and Al2O3 (13.8–15.9wt.%) contents, high Sr/Y ratios (35–79), low compatible element contents (e.g. Ni=0.9–7.2ppm; Cr =1.0–8.2ppm), low Mg# values (0.19–0.35), positive LILE anomalies, marked negative high HFSE anomalies, negative εNd(t) values (−6 to −2), and high (87Sr/86Sr)i values (0.7071–0.7081). These features indicate that the host porphyries were mainly formed by partial melting of subduction-modified lower crust with a certain assimilation of mafic melts represented by MMEs. MMEs hosted in the Beiya porphyries, formed from a hydrous, mafic magma although they formed in a non-arc setting. High magmatic water content is probably related to an enriched mantle metasomatized by fluids from a Proterozoic subducted oceanic slab. High Cu (341–626ppm) and Au contents of the MMEs suggest they crystallized from a metal-rich mafic melt. Complex assemblages of pyrite–chalcopyrite–apatite–rutile with hornblende are observed in the least altered MME. We suggest that the mafic melt probably supplied part of water, and metal to the Beiya porphyry Au system.

Bisphosphonates Inhibit Pain, Bone Loss, and Inflammation in a Rat Tibia Fracture Model of Complex Regional Pain Syndrome.

Bisphosphonates are used to prevent the bone loss and fractures associated with osteoporosis, bone metastases, multiple myeloma, and osteogenesis deformans. Distal limb fractures cause regional bone loss with cutaneous inflammation and pain in the injured limb that can develop into complex regional pain syndrome (CRPS). Clinical trials have reported that antiresorptive bisphosphonates can prevent fracture-induced bone loss, inhibit serum inflammatory cytokine levels, and alleviate CRPS pain. Previously, we observed that the inhibition of inflammatory cytokines or adaptive immune responses attenuated the development of pain behavior in a rat fracture model of CRPS, and we hypothesized that bisphosphonates could prevent pain behavior, trabecular bone loss, postfracture cutaneous cytokine upregulation, and adaptive immune responses in this CRPS model. Rats underwent tibia fracture and cast immobilization for 4 weeks and were chronically administered either subcutaneously perfused alendronate or oral zoledronate. Behavioral measurements included hindpaw von Frey allodynia, unweighting, warmth, and edema. Bone microarchitecture was measured by microcomputed tomography, and bone cellular activity was evaluated by static and dynamic histomorphometry. Spinal cord Fos immunostaining was performed, and skin cytokine (tumor necrosis factor, interleukin [IL]-1, IL-6) and nerve growth factor (NGF) levels were determined by enzyme immunoassay. Skin and sciatic nerve immunoglobulin levels were determined by enzyme immunoassay. Rats with tibia fractures developed hindpaw allodynia, unweighting, warmth, and edema, increased spinal Fos expression and trabecular bone loss in the lumbar vertebra and bilateral distal femurs as measured by microcomputed tomography, increased trabecular bone resorption and osteoclast surface with decreased bone formation rates, increased cutaneous inflammatory cytokine and NGF expression, and elevated immunocomplex deposition in skin and nerve. Alendronate (60 μg/kg/d subcutaneously [s.c.]) or zoledronate (3 mg/kg/d orally) treatment for 28 days, started at the time of fracture, completely inhibited the development of hindpaw allodynia and reduced hindpaw unweighting by 44% ± 13% and 58% ± 5%, respectively. Orally administered zoledronate (3 mg/kg/d for 21 days) treatment also completely reversed established allodynia and unweighting when started at 4 weeks postfracture. Histomorphometric and microcomputed tomography analysis demonstrated that both the 3 and 60 μg/kg/d alendronate treatments reversed trabecular bone loss (an 88% ± 25% and 188% ± 39% increase in the ipsilateral distal femur BV/TV, respectively) and blocked the increase in osteoclast numbers and erosion surface observed in bilateral distal femurs and in L5 vertebra of the fracture rats. Alendronate treatment inhibited fracture-induced increases in hindpaw inflammatory mediators, reducing postfracture levels of tumor necrosis factor by 43% ± 9%, IL-1 by 60% ± 9%, IL-6 by 56% ± 14%, and NGF by 37% ± 14%, but had no effect on increased spinal cord Fos expression, or skin and sciatic nerve immunocomplex deposition. Collectively, these results indicate that bisphosphonate therapy inhibits pain, osteoclast activation, trabecular bone loss, and cutaneous inflammation in the rat fracture model of CRPS, data supporting the hypothesis that bisphosphonate therapy can provide effective multimodal treatment for CRPS.

Lateral Ridge Augmentation Using Autogenous Block Grafts and Guided Bone Regeneration: A 10-Year Prospective Case Series Study.

The use of autogenous block grafts harvested from intraoral donor sites has proven to be effective for the reconstruction of horizontal bone defects. The objective of this study was to analyze implant success and the rate of block graft resorption 10 years after ridge augmentation to elucidate contributing factors influencing graft maintenance. A staged horizontal block graft augmentation was performed in 52 implant sites exhibiting severe horizontal bone atrophy using autogenous block grafts protected by DBBM and collagen membranes. The crest width was assessed intraoperatively at surgery and at re-entry after 6 months. At the 10 year reexamination clinical and radiographic parameters were assessed using cone beam computed tomography. The 10-year implant success rate amounted to 98.1%, with minimal peri-implant bone loss (-0.17 mm for the maxilla, -0.09 mm for the mandible). The surface resorption rate after 10 years was 7.7% (0.38 mm). Grafts originating from the chin demonstrated significantly better graft maintenance at 10 years compared to retromolar grafts. Recipient site and age had no significant impact on graft resorption, whereas females showed more bone loss at the 10-year examination. Lateral ridge augmentation using autogenous block grafts and guided bone regeneration demonstrated a favorable success rate of 98.1% with minimal block graft resorption of 7.7% after 10 years. Modulating factors were origin of the graft and gender.

Heterogeneity of osteoclast activity and bone turnover in different skeletal sites

ObjectiveTo compare osteoclasts and bone turnover in the cranial and appendicular skeletons of mice and determine whether estrogen depletion has an impact on these differences. DesignIn vitro osteoclastogenesis (OCG) was performed on osteoclasts precursors derived from calvarial, mandibular and femoral bone marrow. In vitro, mature osteoclasts were stained with TRAP in plastic petri dishes and with DAPI and Phalloidin on glass coverslips to identify mature osteoclasts and compare osteoclast surface area and nuclei number in the different bone sites, respectively. Quantification of osteoclast resorption pit (Rpit) volume and surface area from different bone sites was achieved using dentin slices stained with Picrosirius red and confocal microscopy. In vivo TRAP, static and dynamic histomorphometric analyses were performed on 5-month-old mouse calvarial, long bone and mandibular trabecular bone to compare bone resorption and formation rates, respectively. Mice were ovariectomized (OVX) at 5 months of age and sacrificed at 6 months of age to establish an osteoporosis model for differences in osteoclasts activity and to monitor the changes in bone turnover rates in the three bone sites upon estrogen depletion. Results Phalloidin stained calvarial osteoclasts were larger compared to long bone and mandibular osteoclasts. Rpits from osteoclasts derived from mandibular bone were smaller and had lower volume values compared to long bone and calvarial bone Rpits. In vivo analysis showed significant increases in bone formation rates in calvarial trabecular bone compared to long bone and mandibular trabecular bone. Turnover was enhanced upon estrogen depletion in calvarial trabecular bone. Resorption was increased without a corresponding increase in bone formation in the trabecular metaphysis of long bone. Mandibular trabecular bones do not appear to be affected by OVX. ConclusionThe cranial and appendicular skeletons differ from one another in that osteoclasts from calvarial bone have the highest resorptive capacity which is coupled to bone formation both pre and post-OVX. Mandibular bones show the lowest turnover rates and are not affected by OVX.

Abstract 3791: TRPV6 calcium channel peptide antagonists as novel antimyeloma and antiresorptive agents

Abstract Background: Multiple myeloma and its associated bone disease are generally incurable. Hence, better therapies are needed, ideally targeting biomolecules implicated in the aberrant biology of the disease. Overexpression of transient receptor potential cation channel TRPV6, a highly selective calcium channel has been observed in breast, colon, thyroid, ovary and prostate cancer tissues, and in several tumour cell lines. TRPV6 expression has also been seen in osteoclasts, however its role in bone metabolism remains unclear. The reciprocal interaction between osteoclasts and myeloma cells is pivotal to the generation of bone lesions that characterize myeloma. While myeloma cells secrete factors promoting osteoclast activity, osteoclasts in turn are known to induce myeloma cell growth and survival. The TRPV6 peptide antagonist SOR-C13 is currently in phase I clinical trials as an anti-cancer therapy for advanced cancers. We investigated the expression and potential therapeutic significance of TRPV6 in human osteoclasts and myeloma cells using shrew venom derived peptide antagonists. Methods: High affinity TRPV6 peptide antagonists SOR-C13 and SOR-C27 derived from the C-terminus of venom from the short-tailed shrew, Blarina brevicauda were used. Human primary osteoclasts were generated in vitro from human bone marrow (BM) aspirates; characterized by Hoechst-phalloidin staining, Tartrate resistant acid phosphatase (TRAP) staining, TRAP enzyme activity and Cathepsin K expression. CD138 positive myeloma cells were isolated from patient bone marrow specimens by EasySep immunomagnetic separation, or examined in tissue microarrays of patient BM core biopsies. TRPV6 expression in primary human osteoclasts, myeloma cell lines and myeloma patient BM microarray was checked by qPCR, immunohistochemistry or immunoblotting. Anti-resorptive potential of SOR peptides using human osteoclasts was evaluated in Osteoassay plates that mimic bone, and myeloma cell growth inhibition was determined by prestoblue cell viability assays. Results: We found strong expression of TRPV6 protein in human myeloma cells and osteoclasts by immunohistochemical staining on myeloma patient bone marrow sections. Human osteoclasts generated in vitro and CD138 positive myeloma patient bone marrow plasma cells were found to express TRPV6. We saw dose-dependent inhibition of osteoclast activity in vitro by SOR-C13 and SOR-C27, including markedly reduced osteoclast formation, decreased TRAP activity and reduced osteoassay surface resorption. TRPV6 peptide antagonists were also found to inhibit the growth of human myeloma cell lines U266 and KMM-1. Conclusion: Anti-myeloma and anti-osteoclast activity of human TRPV6 antagonist peptides was seen in the current study. Taken together, our findings suggest a novel therapeutic approach for multiple myeloma involving TRPV6 inhibition to target both myeloma cells and osteoclasts. Citation Format: Alli Murugesan, Philippe Tremblay, Ming Han, Bithika Ray, Tyler Lutes, Tony Reiman. TRPV6 calcium channel peptide antagonists as novel antimyeloma and antiresorptive agents. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3791.

Efficacy of the comprehensive antiresorptive therapy at different stages of surgical rehabilitation in dentition defects in female patients with postmenopausal osteoporosis

Question of the interrelationship of systemic disorders of bone remodeling and the condition of the bone tissue of the alveolar bone, as well as the efficiency of comprehensive antiresorptive therapy at different stages of surgical rehabilitation in dentition defects in female patients with postmenopausal osteoporosis (PMOP) requires further clarification and remains a subject of active discussion of scientists and clinicians. In the study there was demonstrated that in PMOP female patients with atrophy of the alveolar process of the maxilla in edentulous area there is noted was a significant excess in indices of bone turnover (TNF-alpha level - by 184%, IL-1 - 224%, IL-6- 85%, CTx -156% osteocalcin - 32.9%, PTH- 55%) against the background of the reduced level of a D(OH)25 (by 25.8%) in comparison with patients of reproductive age without osteoporosis. These data correlate with a significant increase in indices of osteosynthesis (index level of the osteoid volume - by 17.6%, index of total resorptive surface by - 51.5%) and a decrease in bone quality indices (index level of the total volume of trabecules - by 60%, index of average width of trabeculae - by 40 %) according to results of the histological examination of bioptate of the process from the edentulous area. At that in PMOP patients with concomitant accompanying somatic pathology the level of TNF-a, IL-1, IL-6 and CTx was significantly higher than in patients of this the group without comorbidity. Appointment of the comprehensive antiresorptive therapy at all stages of surgical rehabilitation (open sinus lifting, dental implantation) in PMOP patients with atrophy of the maxilla in edentulous area during the year before and after sinus lifting significantly increasedthe efficiency of the dental implant. Supplementation of NSAIDs (Arcoxia 60 mg per day) for 2 months prior to dental implantation and within 1 month after a comprehensive antiresorptive therapy in PMOP patients with concomitant estrogen-induced pathology also significantly increases the efficiency of the dental implant in comparison with given indices in patients which received no combined therapy.

Anterior Maxilla Augmentation Using Palatal Bone Block with Platelet-Rich Fibrin: A Controlled Trial.

This study was conducted to characterize clinically and radiographically the effect of using platelet-rich fibrin (PRF) autologous graft on the augmentation results of autogenous palatal bone blocks. Patients who suffered from horizontal alveolar bone defects in the anterior maxillary ridge (≤ 4.5 mm) with one or two missing teeth were augmented with autogenous palatal bone blocks 4 months prior to implant placement. PRF was used to cover the block in the test group, while only the block was used in the control. Bone width was measured with a manual caliper preaugmentation (t0), and at 0 (t1) and 4 months (t2). Cone beam computed tomography (CBCT) scans were performed at t0 and t2. Nonparametric tests (Mann-Whitney, Friedman's, and Wilcoxon signed-rank tests) were used for the comparisons. The significance level was set at P ≤ .05. In the 14 sites (12 patients), all but one autograft (from the control group) integrated successfully after 4 months. No statistically significant difference was found between demographic data in the two groups. There was a statistically significant increase in the buccopalatal bone width in both groups by time as measured by CBCT as well as the manual caliper. The test group showed statistically significantly lower mean graft resorption than the control group (test, 0.8 ± 0.6 mm; control, 1.6 ± 0.9 mm; P = .006). Autogenous palatal bone block surface resorption is significantly decreased by the use of PRF coverage.

Bone Canopies in Pediatric Renal Osteodystrophy.

Pediatric renal osteodystrophy (ROD) is characterized by changes in bone turnover, mineralization, and volume that are brought about by alterations in bone resorption and formation. The resorptive and formative surfaces on the cancellous bone are separated from the marrow cavity by canopies consisting of a layer of flat osteoblastic cells. These canopies have been suggested to play a key role in the recruitment of osteoprogenitors during the process of bone remodeling. This study was performed to address the characteristics of the canopies above bone formation and resorption sites and their association with biochemical and bone histomorphometric parameters in 106 pediatric chronic kidney disease (CKD) patients (stage 2–5) across the spectrum of ROD. Canopies in CKD patients often appeared as thickened multilayered canopies, similar to previous reports in patients with primary hyperparathyroidism. This finding contrasts with the thin appearance reported in healthy individuals with normal kidney function. Furthermore, canopies in pediatric CKD patients showed immunoreactivity to the PTH receptor (PTHR1) as well as to the receptor activator of nuclear factor kappa-B ligand (RANKL). The number of surfaces with visible canopy coverage was associated with plasma parathyroid hormone (PTH) levels, bone formation rate, and the extent of remodeling surfaces. Collectively, these data support the conclusion that canopies respond to the elevated PTH levels in CKD and that they possess the molecular machinery necessary to respond to PTH signaling.