Early diagnosis and aggressive surgical resection matters to cure rhinocerebral mucormycosis: Six case reports.

Rhino-cerebral mucormycosis (RM) is a rare and opportunistic fungal infection observed in immune-compromised patients and metabolic imbalances such as Diabetes Mellitus. RM rapidly infiltrates blood vessels, leading to vascular thrombosis, subsequent tissue necrosis, and high mortality rates (23.6-60%). Due to its fast advancement, RM is a life-threatening condition requiring accurate clinical decisions by the medical and surgical teams. Based on the report of six cases, we emphasize the need for an early diagnosis and starting antifungal pharmacological therapy at the slightest suspicion of RM. Moreover, the restitution of metabolic balance and aggressive surgical debridement are vital steps to control RM, reducing the possibility of fatal outcomes.

Roles of inflammatory cell infiltrate in periprosthetic osteolysis.

Classically, particle-induced periprosthetic osteolysis at the implant-bone interface has explained the aseptic loosening of joint replacement. This response is preceded by triggering both the innate and acquired immune response with subsequent activation of osteoclasts, the bone-resorbing cells. Although particle-induced periprosthetic osteolysis has been considered a foreign body chronic inflammation mediated by myelomonocytic-derived cells, current reports describe wide heterogeneous inflammatory cells infiltrating the periprosthetic tissues. This review aims to discuss the role of those non-myelomonocytic cells in periprosthetic tissues exposed to wear particles by showing original data. Specifically, we discuss the role of T cells (CD3+, CD4+, and CD8+) and B cells (CD20+) coexisting with CD68+/TRAP- multinucleated giant cells associated with both polyethylene and metallic particles infiltrating retrieved periprosthetic membranes. This review contributes valuable insight to support the complex cell and molecular mechanisms behind the aseptic loosening theories of orthopedic implants.

The salivary peptide histatin-1 enhances bone repair in vivo.

The salivary peptide histatin-1 was recently described as a novel osteogenic factor that stimulates cell adhesion, migration, and differentiation in bone-lineage cells. Since these cell responses collectively contribute to bone regeneration, we hypothesized that histatin-1 harbors the capacity to enhance bone tissue repair at the preclinical level. By using a model of monocortical bone defect, we explored the effects of histatin-1 in tibial mineralization and organic matrix formation in vivo. To this end, different amounts of histatin-1 were embedded in one-mm3 collagen sponges and then applied to tibial monocortical defects in C57bl/6 mice. After seven days, mice were euthanized, and samples were processed for subsequent analysis. Micro-computed tomography screening showed that histatin-1 increased intraosseous mineralization, and this phenomenon was accompanied by augmented collagen matrix deposition and closure of cortical defect edges, as determined by Hematoxylin-Eosin and Masson's Trichrome staining. Moreover, immunohistochemical analyses showed that histatin-1 increased the expression of the osteogenic marker alkaline phosphatase, which was accompanied by augmented blood vessel formation. Collectively, our findings show that histatin-1 itself promotes bone regeneration in an orthotopic model, proposing this molecule as a therapeutic candidate for use in bone regenerative medicine.

Accuracy of transcutaneous bilirubin measurement in full-term newborns at 3400 meters above sea level / Precisión de la bilirrubinometría transcutánea en recién nacidos a término a 3400 metros sobre el nivel del mar

Abstract Background: Neonatal jaundice is a frequent benign condition in newborns. However, a rapid diagnosis must be established for its most appropriate treatment. The objective of this study was to measure the correlation between total serum bilirubin (TSB) and transcutaneous bilirubin (in forehead and sternum) in full-term newborns at 3400 m above sea level. Methods: We conducted a prospective and cross-sectional study in full-term newborns with clinical jaundice from the Hospital Regional in Cusco-Peru. General characteristics and measurement of TSB, transcutaneous forehead bilirubin (TcBF), and transcutaneous bilirubin in the sternum (TcBS) were explored. Correlation, sensitivity, and specificity were calculated. Receiver operating characteristic (ROC) curves were constructed using the SPSS statistical package, version 22.0. Results: A total of 123 newborns were evaluated. The mean bilirubin values were 13.7 ± 3.5 for TcBF, 14.1 ± 3.1 for TcBS, and 13.8 ± 3.9 for TSB. In addition, Pearson correlation coefficients between TSB/TcBF and TSB/TcBS were 0.90 and 0.91, respectively (p < 0.001). For the percentile 95 cut-off point, a sensitivity of 93% and 100% and a specificity of 89% and 80% were obtained for TcBF and TcBS, respectively, with an area under the curve of 0.813 for TcBF and 0.815 for TcBS (p < 0.001) Conclusions: Measurement of transcutaneous bilirubin is a fast and painless method that can be considered a reliable tool for screening and monitoring neonatal jaundice, but not for a definitive diagnosis to decide the use of phototherapy in full-term newborns at 3400 m above sea level.

Resumen Introducción: La ictericia neonatal es una condición benigna y frecuente en los recién nacidos, en quienes es preciso hacer un diagnóstico rápido para el tratamiento más adecuado. El objetivo de este estudio fue determinar la correlación entre la bilirrubina sérica total (BST) y la bilirrubina transcutánea (frente y esternón) en recién nacidos a término a 3400 metros sobre el nivel del mar. Método: Estudio prospectivo y transversal en recién nacidos con ictericia clínica en el Hospital Regional de la Ciudad de Cusco, Perú. Se exploraron las características generales y se midieron la BST, la bilirrubina transcutánea en la frente (BTcF) y la bilirrubina transcutánea en el esternón (BTcE). Se calcularon la correlación, la sensibilidad y la especificidad, y se elaboraron las curvas de características operativas del receptor (ROC) con el paquete estadístico SPSS 22.0. Resultados: Se evaluaron 123 recién nacidos. El promedio de la BST fue de 13.8 ± 3.9, el de la BTcF fue de 13.7 ± 3.5 y el de la BTcE fue de 14.1 ± 3.1. La correlación entre BST/BTcF y BST/BTcE fue de 0.90 y 0.91, respectivamente (p < 0.001). Para el punto de corte del percentil 95 según el nomograma Bhutani se obtuvo una sensibilidad del 93% y el 100%, y una especificidad del 89% y el 80%, para la BTcF y la BTcE, respectivamente, con un área bajo la curva ROC de 0.813 para la BTcF y de 0.815 para la BTcE (p < 0.001). Conclusiones: La medición de la bilirrubina transcutánea es un método rápido e indoloro, y podría ser considerado confiable para el despistaje y el seguimiento de la ictericia neonatal, mas no para un diagnóstico definitivo con el fin de decidir el uso de fototerapia en recién nacidos a término a 3400 metros sobre el nivel del mar.

Osteoimmunology drives dental implant osseointegration: A new paradigm for implant dentistry.

There is a complex interaction between titanium dental implants, bone, and the immune system. Among them, specific immune cells, macrophages play a crucial role in the osseointegration dynamics. Infiltrating macrophages and resident macrophages (osteomacs) contribute to achieving an early pro-regenerative peri-implant environment. Also, multinucleated giant cells (MNGCs) in the bone-implant interface and their polarization ability, maintain a peri-implant immunological balance to preserve osseointegration integrity. However, dental implants can display cumulative levels of antigens (ions, nano and microparticles and bacterial antigens) at the implant-tissue interface activating an immune-inflammatory response. If the inflammation is not resolved or reactivated due to the stress signals and the immunogenicity of elements present, this could lead implants to aseptic loosening, infections, and subsequent bone loss. Therefore, to maintain osseointegration and prevent bone loss of implants, a better understanding of the osteoimmunology of the peri-implant environment would lead to the development of new therapeutic approaches. In this line, depicting osteoimmunological mechanisms, we discuss immunomodulatory strategies to improve and preserve a long-term functional integration between dental implants and the human body. Scientific field of dental science: implant dentistry.

Dysregulated healing response participates in the pathophysiology of temporomandibular joint ankylosis.

This study aimed to characterize samples from patients diagnosed with TMJ ankylosis, using both clinical and histological data. Both clinical and histological analyses of retrieved tissue samples from patients with primary TMJ ankyloses were performed retrospectively (1980-2012). All patients had been subjected to primary arthroplasty. Our study analyzed connective tissue differentiation, ossification patterns, and bone resorption, using histology and immunohistochemistry. Fifteen case records, with a sex ratio of 4:1 (men:woman) and a median age of 8 years, were collected. Six patient samples reported a previous inflammatory event. Histologically, 15 samples exhibited fibrous tissue. Among these, 13 displayed bone at different stages of maturity (fibrous/bony ankylosis). Eleven samples showed aberrant cartilage, characterized by hypertrophic chondrocyte-like cells at the bone/cartilage interface. Four samples revealed inflammatory infiltrate; in one case, this was organized as a lymphoid follicle. Eleven samples showed bone resorption by attached osteoclasts. Interestingly, non-attached osteoclasts were detected, suggesting locally impaired bone remodeling. An association between the presence of mature/lamellar bone and the presence of osteoclasts was observed (p = 0.03). No association was found between previous history of either trauma or infection and the histological type of ankylosis (p = 0.74). There was no association between the histological presence of inflammation or infection and the type of ankylosis (p = 0.63 and p = 0.87, respectively). Retrieved TMJ ankylosis tissues displayed both aberrant ossification and reduced focal bone resorption, suggesting a dysregulated healing response.

Accuracy of transcutaneous bilirubin measurement in full-term newborns at 3400 meters above sea level.

BACKGROUND: Neonatal jaundice is a frequent benign condition in newborns. However, a rapid diagnosis must be established for its most appropriate treatment. The objective of this study was to measure the correlation between total serum bilirubin (TSB) and transcutaneous bilirubin (in forehead and sternum) in full-term newborns at 3400 m above sea level. METHODS: We conducted a prospective and cross-sectional study in full-term newborns with clinical jaundice from the Hospital Regional in Cusco-Peru. General characteristics and measurement of TSB, transcutaneous forehead bilirubin (TcBF), and transcutaneous bilirubin in the sternum (TcBS) were explored. Correlation, sensitivity, and specificity were calculated. Receiver operating characteristic (ROC) curves were constructed using the SPSS statistical package, version 22.0. RESULTS: A total of 123 newborns were evaluated. The mean bilirubin values were 13.7 ± 3.5 for TcBF, 14.1 ± 3.1 for TcBS, and 13.8 ± 3.9 for TSB. In addition, Pearson correlation coefficients between TSB/TcBF and TSB/TcBS were 0.90 and 0.91, respectively (p < 0.001). For the percentile 95 cut-off point, a sensitivity of 93% and 100% and a specificity of 89% and 80% were obtained for TcBF and TcBS, respectively, with an area under the curve of 0.813 for TcBF and 0.815 for TcBS (p < 0.001). CONCLUSIONS: Measurement of transcutaneous bilirubin is a fast and painless method that can be considered a reliable tool for screening and monitoring neonatal jaundice, but not for a definitive diagnosis to decide the use of phototherapy in full-term newborns at 3400 m above sea level.

Osteoimmunology of Oral and Maxillofacial Diseases: Translational Applications Based on Biological Mechanisms.

The maxillofacial skeleton is highly dynamic and requires a constant equilibrium between the bone resorption and bone formation. The field of osteoimmunology explores the interactions between bone metabolism and the immune response, providing a context to study the complex cellular and molecular networks involved in oro-maxillofacial osteolytic diseases. In this review, we present a framework for understanding the potential mechanisms underlying the immuno-pathobiology in etiologically-diverse diseases that affect the oral and maxillofacial region and share bone destruction as their common clinical outcome. These otherwise different pathologies share similar inflammatory pathways mediated by central cellular players, such as macrophages, T and B cells, that promote the differentiation and activation of osteoclasts, ineffective or insufficient bone apposition by osteoblasts, and the continuous production of osteoclastogenic signals by immune and local stromal cells. We also present the potential translational applications of this knowledge based on the biological mechanisms involved in the inflammation-induced bone destruction. Such applications can be the development of immune-based therapies that promote bone healing/regeneration, the identification of host-derived inflammatory/collagenolytic biomarkers as diagnostics tools, the assessment of links between oral and systemic diseases; and the characterization of genetic polymorphisms in immune or bone-related genes that will help diagnosis of susceptible individuals.

Histatin-1 counteracts the cytotoxic and antimigratory effects of zoledronic acid in endothelial and osteoblast-like cells.

BACKGROUND: Zoledronic acid, the most frequent agent associated with bisphosphonate-related osteonecrosis of the jaw (BRONJ), has been reported as cytotoxic for bone and vascular cells. Hence, identification of novel approaches aiming to counteract its cytotoxic effects will be desirable to develop preventive therapies for BRONJ. The salivary peptide Histatin-1 was recently shown to promote oral wound healing, by acting in epithelial and endothelial cells; however, its effects on cells exposed to zoledronic acid have not been explored. This study aims to unveil the role of Histatin-1 in osteoblastic and vascular cell lineages challenged with zoledronic acid. METHODS: The effects of zoledronic acid (1-100 µM), Histatin-1 (10 µM), or their combination was evaluated in cytotoxicity (Trypan Blue exclusion) and cell migration (Boyden Chamber) assays. Caspase-3 cleavage was evaluated by Western blot. The angiogenic capacity of endothelial cells was assessed in a tubule formation assay in vitro. RESULTS: Zoledronic acid decreased cell viability and migration of osteosarcoma cells (SAOS-2) and preosteoblasts (MC3T3-E1), in a dose-response manner. Importantly, Histatin-1 restored both cell viability and migration in both cell lines upon challenge with zoledronic acid. These effects were recapitulated in endothelial cells (EA.hy926), as Histatin-1 counteracted cytotoxic and antimigratory effects of zoledronic acid, and restored the angiogenic capacity in vitro. CONCLUSION: We conclude that Histatin-1 counteracts the cytotoxic and antimigratory effects of zoledronic acid in osteoblast-like and endothelial cells. These observations highlight the potential use of Histatin-1, in the design of novel therapies aiming to prevent and treat BRONJ.

Efecto antiangiogénico de la triamcinolona asociada a lidocaína con epinefrina de uso odontológico en la membrana alantocoriónica de pollo / Antiangiogenic effect of triamcinolone associated with lidocaine with epinephrine for dental use in chicken chorioallantoic membrane

RESUMEN: El proceso angiogénico se define como el proceso en el que los vasos sanguíneos generan brotes dando como resultado neovascularidad. Un desbalance en el proceso angiogénico contribuye a numerosos desórdenes inflamatorios, infecciosos, isquémicos, inmunológicos y malignos. En el territorio maxilofacial se pueden encontrar patologías neoplásicas benignas de desarrollo local con un marcado componente angiogénico que determinan su crecimiento y agresividad. Sin embargo, existe escasa evidencia de cómo tratarlas en base al control de la angiogénesis. Terry & Jacoway (1994) desarrollaron un protocolo de tratamiento para lesiones neoplásicas benignas con un importante componente vascular que se utiliza actualmente. Este protocolo consiste en la infiltración intralesional de una suspensión de triamcinolona 10 mg/ml más una solución de anestésico local de uso odontológico como la lidocaína al 2 % asociada a epinefrina en una concentración de 1:200.000. Sin embargo, el uso de epinefrina podría disminuir la acción antiangiogénica de la triamcinolona al ser un vasoconstrictor. El objetivo de este estudio es comparar el efecto antiangiogénico, en la membrana alantocoriónica de pollo (MAC), de esta suspensión versus el efecto de la triamcinolona sin asociar a anestésicos locales. Los resultados del efecto antiangiogénico en la MAC de pollo, obtenidos en la investigación concluyeron que la suspensión de triamcinolona asociada a lidocaína con epinefrina es similar al de la suspensión de triamcinolona sin asociar a anestésicos locales. Además, se logró determinar que las suspensiones de triamcinolona sin asociar a anestésicos locales y las asociadas a anestésicos locales con o sin vasoconstrictor poseen un marcado efecto antiangiogénico, en la MAC de pollo, en comparación al grupo control.

SUMMARY: Angiogenesis is defined as the process through which new blood vessels form from previously existing vessels. Several inflammatory, infectious, ischemic, immunological and malignant disorders are caused by the lack of adequate angiogenesis balance. In the maxillofacial area, there are invasive benign neoplastic pathologies with a strong angiogenic component, which determines aggressive behavior and growth. Studies in the literature are scarce regarding treatment of these conditions based on angiogenesis control. Currently, the protocol used to treat these maxillofacial benign neoplastic lesions, was developed in 1994 by Terry & Jacoway and has a strong angiogenic component. Consequently lesions are treated via intra-lesion administration of triamcinolone 10 mg / mL, a solution used in dental local anesthetic, such as lidocaine 2 %, in conjunction with epinephrine at a concentration of 1:200,000. The objective of this study was to compare the antiangiogenic effect of this protocol in chicken chorioallantoic membrane (CAM) without the use of local anesthetic. The results of the antiangiogenic effect in the CAM obtained in this study concluded that the effect of the suspension of triamcinolone associated to lidocaine with epinephrine, is similar to the suspension of triamcinolone without associating local anesthetics. Furthermore, it was determined that suspensions of triamcinolone without local anesthetic, and those associated to local anesthetic with, and without vasoconstrictor have a strong antiangiogenic effect in CAM compared to the control group.

A WNT protein therapeutic improves the bone-forming capacity of autografts from aged animals.

Autografts tend to be unreliable in older patients. Some of these age-related skeletal changes appear to be attributable to a decline in endogenous WNT signaling. We used a functional in vivo transplantation assay to demonstrate that the bone-forming capacity of an autograft can be traced back to a Wnt-responsive cell population associated with the mineralized bone matrix fraction of a bone graft. Micro-CT imaging, flow cytometry and quantitative analyses demonstrate that this mineralized fraction declines with age, along with a waning in endogenous Wnt signaling; together these factors contribute to the age-related deterioration in autograft efficacy. Using a lipid formulation to stabilize the hydrophobic WNT3A protein, we demonstrate that osteogenic capacity can be restored by incubating the bone graft ex vivo with WNT3A. Compared to control bone grafts, WNT-treated bone grafts give rise to three times more bone. These preclinical results establish a pivotal role for WNT signaling in the age-related decline of autologous bone grafting efficacy, and demonstrate a means to restore that efficacy via local, transient amplification of endogenous Wnt signaling.

CCL2, CCL5, and IGF-1 participate in the immunomodulation of osteogenesis during M1/M2 transition in vitro.

The modulation of macrophage phenotype from pro-inflammatory (M1) to tissue healing (M2) via exogenous addition of interleukin-4 (IL-4) facilitates osteogenesis; however, the molecular mediators underlying this phenomenon remain unknown. This study characterizes the IL-4-dependent paracrine crosstalk between macrophages and osteoprogenitors and its effect on osteogenesis in vitro. Primary murine M1 were co-cultured with MC3T3 cells (M1-MC3T3) in both transwell plates and direct co-cultures. To modulate M1 to M2, M1-MC3T3 were treated with IL-4 (20 ng/mL) at day 3 after seeding (M1 + IL-4-MC3T3). Selected molecular targets were assessed at days 3 and 6 after seeding at protein and mRNA levels. Mineralization was assessed at day 21. Transwell M1 + IL-4-MC3T3 significantly enhanced the secretion of CCL2/MCP-1, IGF-1 and to a lesser degree, CCL5/RANTES at day 6. At day 3, alkaline phosphatase (Alpl) was upregulated in direct M1-MC3T3. At day 6, Smurf2 and Insulin growth factor-1 (IGF-1) were downregulated and upregulated, respectively, in direct M1 + IL-4-MC3T3. Finally, M1 + IL-4-MC3T3 increased bone matrix mineralization compared with MC3T3 cells in transwell, but this was significantly less than M1-MC3T3. Taken together, macrophage subtypes enhanced the osteogenesis in transwell setting and the transition from M1 to M2 was associated with an increase in bone anabolic factors CCL2/MCP-1, CCL5/RANTES and IGF-1 in vitro. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3069-3076, 2017.

Orthopaedic wear particle-induced bone loss and exogenous macrophage infiltration is mitigated by local infusion of NF-κB decoy oligodeoxynucleotide.

Excessive production of wear particles from total joint replacements induces chronic inflammation, macrophage infiltration, and consequent bone loss (periprosthetic osteolysis). This inflammation and bone remodeling are critically regulated by the transcription factor NF-κB. We previously demonstrated that inhibition of NF-κB signaling by using the decoy oligodeoxynucleotide (ODN) mitigates polyethylene wear particle-induced bone loss using in vitro and in vivo models. However, the mechanisms of NF-κB decoy ODN action, and in particular its impact on systemic macrophage recruitment, remain unknown. In the current study, this systemic macrophage infiltration was examined in our established murine femoral continuous particle infusion model. RAW264.7 murine macrophages expressing a luciferase reporter gene were injected into the systemic circulation. Quantification of bioluminescence showed that NF-κB decoy ODN reduced the homing of these reporter macrophages into the distal femurs exposed to continuous particle delivery. Particle-induced reduction in bone mineral density at the distal diaphysis of the femur was also mitigated by infusion of decoy ODN. Histological staining showed that the decoy ODN infusion decreased osteoclast and macrophage numbers, but had no significant effects on osteoblasts. Local infusion of NF-κB decoy ODN reduced systemic macrophage infiltration and mitigated particle-induced bone loss, thus providing a potential strategy to treat periprosthetic osteolysis. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3169-3175, 2017.

Decreased osteogenesis in mesenchymal stem cells derived from the aged mouse is associated with enhanced NF-κB activity.

Aging is associated with significant bone loss and delayed fracture healing. NF-κB activation is highly correlated with inflammatory-associated bone diseases including infection, wear particle exposure, and chronic inflammation during natural aging processes. The critical roles of NF-κB in both the pro-inflammatory response and osteoclast-mediated bone resorption have been well defined. However, the biological effects of NF-κB activation in mesenchymal stem cell (MSC)-mediated bone formation remain largely unknown. In the current study, bone marrow-MSCs were isolated from young (8 weeks old) and aged (72 weeks old) mice. NF-κB activity in MSCs at basal levels and under different biological conditions were determined by our recently established lentiviral vector-based luciferase reporter assay. We found that NF-κB activity was increased in aged MSCs at basal levels or when exposed to low dose (10 or 100 ng/ml) lipopolysaccharide (LPS); this effect was not seen when the cells were exposed to higher dose (1 µg/ml) LPS. During osteogenesis, NF-κB activity was increased in aged MSCs at weeks 1 and 2, but showed no significant difference at week 3. Both Smurf2 and TAZ, the NF-κB target genes that regulate osteogenic differentiation, were increased in aged MSCs. In addition, the expression of RANKL was dramatically increased, and OPG was decreased in aged MSCs. Our findings suggest that targeting NF-κB activity in MSCs has the potential to modulate aging-associated bone loss, or enhance bone-healing in aged patients. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:281-288, 2017.

The biological response to orthopedic implants for joint replacement. II: Polyethylene, ceramics, PMMA, and the foreign body reaction.

Novel evidence-based prosthetic designs and biomaterials facilitate the performance of highly successful joint replacement (JR) procedures. To achieve this goal, constructs must be durable, biomechanically sound, and avoid adverse local tissue reactions. Different biomaterials such as metals and their alloys, polymers, ceramics, and composites are currently used for JR implants. This review focuses on (1) the biological response to the different biomaterials used for TJR and (2) the chronic inflammatory and foreign-body response induced by byproducts of these biomaterials. A homeostatic state of bone and surrounding soft tissue with current biomaterials for JR can be achieved with mechanically stable, infection free and intact (as opposed to the release of particulate or ionic byproducts) implants. Adverse local tissue reactions (an acute/chronic inflammatory reaction, periprosthetic osteolysis, loosening and subsequent mechanical failure) may evolve when the latter conditions are not met. This article (Part 2 of 2) summarizes the biological response to the non-metallic materials commonly used for joint replacement including polyethylene, ceramics, and polymethylmethacrylate (PMMA), as well as the foreign body reaction to byproducts of these materials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1685-1691, 2017.

Mutant CCL2 protein coating mitigates wear particle-induced bone loss in a murine continuous polyethylene infusion model.

Wear particle-induced osteolysis limits the long-term survivorship of total joint replacement (TJR). Monocyte/macrophages are the key cells of this adverse reaction. Monocyte Chemoattractant Protein-1 (MCP-1/CCL2) is the most important chemokine regulating trafficking of monocyte/macrophages in particle-induced inflammation. 7ND recombinant protein is a mutant of CCL2 that inhibits CCL2 signaling. We have recently developed a layer-by-layer (LBL) coating platform on implant surfaces that can release biologically active 7ND. In this study, we investigated the effect of 7ND on wear particle-induced bone loss using the murine continuous polyethylene (PE) particle infusion model with 7ND coating of a titanium rod as a local drug delivery device. PE particles were infused into hollow titanium rods with or without 7ND coating implanted in the distal femur for 4 weeks. Specific groups were also injected with RAW 264.7 as the reporter macrophages. Wear particle-induced bone loss and the effects of 7ND were evaluated by microCT, immunohistochemical staining, and bioluminescence imaging. Local delivery of 7ND using the LBL coating decreased systemic macrophage recruitment, the number of osteoclasts and wear particle-induced bone loss. The development of a novel orthopaedic implant coating with anti-CCL2 protein may be a promising strategy to mitigate peri-prosthetic osteolysis.

Severe compromise of preosteoblasts in a surgical mouse model of bisphosphonate-associated osteonecrosis of the jaw.

OBJECTIVES: The effect of amino-bisphosphonates on osteoblastic lineage and its potential contribution to the pathogenesis of bisphosphonate-associated osteonecrosis of the jaw (BONJ) remain controversial. We assessed the effects of zoledronic acid (ZOL) on bone and vascular cells of the alveolar socket using a mouse model of BONJ. MATERIAL AND METHODS: Thirty-two mice were treated twice a week with either 100 µg/kg of ZOL or saline for 12 weeks. The first left maxillary molar was extracted at the third week. Alveolar sockets were assessed at both 3 weeks (intermediate) and 9 weeks (long-term) after molar extraction by semi-quantitative histomorphometry for empty lacunae, preosteoblasts (Osterix), osteoclasts (TRAP), and pericyte-like cells (CD146). Also, the bone microarchitecture was assessed by micro-CT. RESULTS: Osteonecrotic-like lesions were observed in 21% of mice. Moreover, a decreased number of preosteoblasts contrasted with the increased number of osteoclasts at both time points. In addition, osteoclasts display multinucleation and detachment from the endosteal surface. Furthermore, the number of pericyte-like cells increased at the intermediate time point. The alveolar bone mass increased exclusively with long-term ZOL treatment. CONCLUSION: The severe imbalance between bone-forming cells and bone-resorbing cells shown in this study could contribute to the pathogenesis of BONJ.

NF-κB decoy oligodeoxynucleotide mitigates wear particle-associated bone loss in the murine continuous infusion model.

UNLABELLED: Total joint replacement is a cost-effective surgical procedure for patients with end-stage arthritis. Wear particle-induced chronic inflammation is associated with the development of periprosthetic osteolysis. Modulation of NF-κB signaling in macrophages, osteoclasts, and mesenchymal stem cells could potentially mitigate this disease. In the current study, we examined the effects of local delivery of decoy NF-κB oligo-deoxynucleotide (ODN) on wear particle-induced bone loss in a murine continuous femoral particle infusion model. Ultra-high molecular weight polyethylene particles (UHMWPE) with or without lipopolysaccharide (LPS) were infused via osmotic pumps into hollow titanium rods placed in the distal femur of mice for 4weeks. Particle-induced bone loss was evaluated by µCT, and immunohistochemical analysis of sections from the femur. Particle infusion alone resulted in reduced bone mineral density and trabecular bone volume fraction in the distal femur. The decoy ODN reversed the particle-associated bone volume fraction loss around the implant, irrespective of the presence of LPS. Particle-infusion with LPS increased bone mineral density in the distal femur compared with particle-infusion alone. NF-κB decoy ODN reversed or further increased the bone mineral density in the femur (3-6mm from the distal end) exposed to particles alone or particles plus LPS. NF-κB decoy ODN also inhibited macrophage infiltration and osteoclast number, but had no significant effects on osteoblast numbers in femurs exposed to wear particles and LPS. Our study suggests that targeting NF-κB activity via local delivery of decoy ODN has great potential to mitigate wear particle-induced osteolysis. STATEMENT OF SIGNIFICANCE: Total joint replacement is a cost-effective surgical procedure for patients with end-stage arthritis. Chronic inflammation is crucial for the development of wear particle-associated bone loss. Modulation of NF-κB signaling in macrophages (pro-inflammatory cells), osteoclasts (bone-resorbing cells), and osteoblasts (bone-forming cells) could potentially mitigate this disease. Here we demonstrated that local delivery of decoy NF-κB oligo-deoxynucleotide (ODN) mitigated ultra-high molecular weight polyethylene (UHMWPE) wear particle induced bone loss in a clinically relevant murine model. The protective effects of decoy ODN was associated with reduced macrophage infiltration and osteoclast activation, but had no significant effects on osteoblast numbers. Our study suggests that targeting NF-κB activity via local delivery of decoy ODN has great potential to mitigate wear particle-induced bone loss.

Pro-osteoclastic in vitro effect of Polyethylene-like nanoparticles: Involvement in the pathogenesis of implant aseptic loosening.

Polyethylene micro-sized wear particles released from orthopedic implants promote inflammation and osteolysis; however, less is known about the bioactivity of polyethylene nanosized wear particles released from the last generation of polymer-bearing surfaces. We aim to assess the internalization of fluorescent polyethylene-like nanoparticles by both human macrophages and osteoclasts and also, to determine their effects in osteoclastogenesis in vitro. Human macrophages and osteoclasts were incubated with several ratios of fluorescent polyethylene-like nanoparticles between 1 and 72 h, and 4 h, 2, 4, 6, and 9 days, respectively. The internalization of nanoparticles was quantified by flow cytometry and followed by both confocal and video time-lapse microscopy. Osteoclast differentiation and activity was semiquantified by tartrate-resistant acid phosphatase (TRAP) staining, TRAP mRNA relative expression, and pit resorption assay, respectively. Macrophages, osteoclast precursors and mature osteoclasts internalized nanoparticles in a dose- and time-dependent manner and maintained their resorptive activity. In addition, nanoparticles significantly increased the osteoclastogenesis as shown by upregulation of the TRAP expressing cell number. We conclude that polyethylene-like nanosized wear particles promote osteoclast differentiation without alteration of bone resorptive activity of mature osteoclasts and they could be considered as important actors in periprosthetic osteolysis of the last new generation of polymer-bearing surfaces. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2649-2657, 2016.

Inflammation, fracture and bone repair.

The reconstitution of lost bone is a subject that is germane to many orthopedic conditions including fractures and non-unions, infection, inflammatory arthritis, osteoporosis, osteonecrosis, metabolic bone disease, tumors, and periprosthetic particle-associated osteolysis. In this regard, the processes of acute and chronic inflammation play an integral role. Acute inflammation is initiated by endogenous or exogenous adverse stimuli, and can become chronic in nature if not resolved by normal homeostatic mechanisms. Dysregulated inflammation leads to increased bone resorption and suppressed bone formation. Crosstalk among inflammatory cells (polymorphonuclear leukocytes and cells of the monocyte-macrophage-osteoclast lineage) and cells related to bone healing (cells of the mesenchymal stem cell-osteoblast lineage and vascular lineage) is essential to the formation, repair and remodeling of bone. In this review, the authors provide a comprehensive summary of the literature related to inflammation and bone repair. Special emphasis is placed on the underlying cellular and molecular mechanisms, and potential interventions that can favorably modulate the outcome of clinical conditions that involve bone repair.