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1.
J Biomed Mater Res B Appl Biomater ; 112(9): e35478, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39223072

RESUMEN

Despite the numerous studies on biocompatibility with nano-biomaterials, the biological effects of strontium-substituted HA nanoparticles (nSrHA) need to be better understood. So, we conducted an embryotoxicity test using zebrafish (Danio rerio) according to the OECD 236 guideline, a model that represents a viable alternative that bridges the gap between in vitro and mammalian models. Zebrafish embryos were exposed for 120 h to microspheres containing nSrHA nanoparticles with low and high crystallinity, synthesized at temperatures of 5°C (nSrHA5) and 90°C (nSrHA90). We evaluated lethality, developmental parameters, and reactive oxygen species (ROS) production. The larval behavior was assessed at 168 hpf to determine if the biomaterials affected motor responses and anxiety-like behavior. The results showed that the survival rate decreased significantly for the nSrHA5 group (low crystalline particles), and an increase in ROS was also observed in this group. However, none of the biomaterials caused morphological changes indicative of toxicity during larval development. Additionally, the behavioral tests did not reveal any alterations in all experimental groups, indicating the absence of neurotoxic effects from exposure to the tested biomaterials. These findings provide valuable insights into the biosafety of modified HA-based nanostructured biomaterials, making them a promising strategy for bone tissue repair. As the use of hydroxyapatite-based biomaterials continues to grow, it is crucial to ensure rigorous control over the quality, reliability, and traceability of these materials.


Asunto(s)
Estroncio , Pez Cebra , Animales , Estroncio/química , Estroncio/farmacología , Especies Reactivas de Oxígeno/metabolismo , Embrión no Mamífero/efectos de los fármacos , Ensayo de Materiales , Hidroxiapatitas/química , Hidroxiapatitas/farmacología , Nanoestructuras/química , Larva/efectos de los fármacos
2.
Materials (Basel) ; 17(16)2024 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-39203270

RESUMEN

The increasing demand for effective bone regeneration materials drives the exploration of biomaterials with enhanced bioactivity and biocompatibility, such as zinc-substituted compounds. This study investigates the in vitro cellular interactions with nanostructured spheres composed of alginate/carbonated hydroxyapatite (CHA), compared to zinc-substituted CHA (ZnCHA). This work aimed to compare the physicochemical properties and biological effects of ZnCHA and CHA on osteoblasts. ZnCHA was synthesized using a wet chemical method, followed by characterization through X-ray diffraction, Fourier transform infrared spectroscopy, total organic carbon analysis, Wavelength-dispersive X-ray spectroscopy, and BET surface area analysis to assess ion release and structural changes. Biological evaluation was conducted using cell viability, proliferation, and biomineralization assays on osteoblasts. Results showed successful incorporation of zinc and carbonate, leading to reduced crystallinity and increased surface area. Cell viability and proliferation assays indicated ZnCHA's cytocompatibility and enhanced osteoblastic activity, with increased mineralization nodules compared to CHA samples. The study concludes that ZnCHA composites are promising candidates for bone tissue engineering, demonstrating improved cytocompatibility and potential for further preclinical evaluations.

3.
J Funct Biomater ; 15(7)2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-39057300

RESUMEN

Zinc is known for its role in enhancing bone metabolism, cell proliferation, and tissue regeneration. Several studies proposed the incorporation of zinc into hydroxyapatite (HA) to produce biomaterials (ZnHA) that stimulate and accelerate bone healing. This systematic review aimed to understand the physicochemical characteristics of zinc-doped HA-based biomaterials and the evidence of their biological effects on osteoblastic cells. A comprehensive literature search was conducted from 2022 to 2024, covering all years of publications, in three databases (Web of Science, PUBMED, Scopus), retrieving 609 entries, with 36 articles included in the analysis according to the selection criteria. The selected studies provided data on the material's physicochemical properties, the methods of zinc incorporation, and the biological effects of ZnHA on bone cells. The production of ZnHA typically involves the wet chemical synthesis of HA and ZnHA precursors, followed by deposition on substrates using processes such as liquid precursor plasma spraying (LPPS). Characterization techniques confirmed the successful incorporation of zinc into the HA lattice. The findings indicated that zinc incorporation into HA at low concentrations is non-cytotoxic and beneficial for bone cells. ZnHA was found to stimulate cell proliferation, adhesion, and the production of osteogenic factors, thereby promoting in vitro mineralization. However, the optimal zinc concentration for the desired effects varied across studies, making it challenging to establish a standardized concentration. ZnHA materials are biocompatible and enhance osteoblast proliferation and differentiation. However, the mechanisms of zinc release and the ideal concentrations for optimal tissue regeneration require further investigation. Standardizing these parameters is essential for the effective clinical application of ZnHA.

4.
Acta Cir Bras ; 39: e392824, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39046039

RESUMEN

PURPOSE: to evaluate biocompatibility and osteogenic potential of hydroxyapatite/alginate composite after its implantation on rat calvarian critical bone defect. METHODS: thirty adults male Wistar rats were randomly distributed into two groups: GHA - critical bone defect filled with hydroxyapatite/alginate composite granules (HA/Alg) and CG - critical bone defect without biomaterial; evaluated at biological points of 15, 45 and 120 days. RESULTS: the histomorphometrically analyses for GHA showed osteoid matrix deposition (OM) among the granules and towards the center of the defect in centripetal direction throughout the study, with evident new bone formation at 120 days, resulting in filling 4/5 of the initial bone defect. For CG, this finding was restricted to the edges of the bone margins and formation of connective tissue on the residual area was found in all biological points. Inflammatory response on GHA was chronic granulomatous type, discrete and regressive for all biological points. Throughout the study, the CG presented mononuclear inflammatory infiltrate diffuse and regressive. Histomorphometry analyses showed that OM percentage was evident for GHA group when compared to CG group in all analyzed periods (p > 0.05). CONCLUSIONS: the biomaterial evaluated at this study showed to be biocompatible, bioactive, osteoconductive and biodegradable synchronously with bone formation.


Asunto(s)
Alginatos , Materiales Biocompatibles , Regeneración Ósea , Sustitutos de Huesos , Durapatita , Ensayo de Materiales , Ratas Wistar , Animales , Masculino , Regeneración Ósea/efectos de los fármacos , Regeneración Ósea/fisiología , Alginatos/farmacología , Durapatita/farmacología , Durapatita/uso terapéutico , Materiales Biocompatibles/uso terapéutico , Sustitutos de Huesos/uso terapéutico , Distribución Aleatoria , Osteogénesis/efectos de los fármacos , Osteogénesis/fisiología , Ácidos Hexurónicos/farmacología , Ácido Glucurónico/farmacología , Cráneo/cirugía , Cráneo/efectos de los fármacos , Factores de Tiempo , Ratas , Reproducibilidad de los Resultados
5.
PLoS One ; 19(6): e0306288, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38917190

RESUMEN

[This corrects the article DOI: 10.1371/journal.pone.0294044.].

6.
PLoS One ; 19(1): e0294044, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38241217

RESUMEN

Many pet owners make food choices for their pets that are similar to those they make for themselves, and food characteristics such as the presence of preservatives can influence this decision. The Theory of Planned Behavior (TPB) is a tool used to predict intentions and behavior and can be an important indicator for the pet food industry. The aim of this study was to investigate pet owner behavior regarding food with or without preservatives, based on the behavior prediction of TPB. A questionnaire was distributed with questions related to direct (attitude, subjective norms, and perceived behavioral control) and indirect (behavioral beliefs, normative beliefs, and intentions) measures for the analysis of TPB. For the statistical analysis the structural equation modeling (SEM) was used. The correlation between owner behavior and the behavior imposed on their dog's diet was evaluated by paired T test or paired Wilcoxon test according to variables' adherence or not to normality, respectively. A total of 1,021 answers were evaluated after the inclusion and exclusion criteria were applied. The results indicated that TPB was effective in predicting the intentions (r2 = 0.58 for dogs and r2 = 0.59 for owners) and behavior (r2 = 0.58 for dogs and r2 = 0.57 for owners) regarding the intake of diets without preservatives. It was observed that owners are more concerned with the diet of their dogs than their own and they believe that the intake of preservatives can be prejudicial to the health of their dogs (p<0.001). However, owners trust more in pet food manufacturers than human food manufacturers (p<0.001). Therefore, it can be concluded that TPB can be an important tool to understand consumer behavior towards their dog food, and that the industry should intensify its approach on safety of preservatives in pet food, since many owners still believe they can be prejudicial to dogs.


Asunto(s)
Actitud , Teoría del Comportamiento Planificado , Humanos , Perros , Animales , Alimentos , Intención , Dieta/veterinaria , Encuestas y Cuestionarios , Conservadores Farmacéuticos
7.
Acta cir. bras ; 39: e392824, 2024. tab, graf, ilus
Artículo en Inglés | LILACS, VETINDEX | ID: biblio-1563652

RESUMEN

Purpose: to evaluate biocompatibility and osteogenic potential of hydroxyapatite/alginate composite after its implantation on rat calvarian critical bone defect. Methods: thirty adults male Wistar rats were randomly distributed into two groups: GHA ­ critical bone defect filled with hydroxyapatite/alginate composite granules (HA/Alg) and CG ­ critical bone defect without biomaterial; evaluated at biological points of 15, 45 and 120 days. Results: the histomorphometrically analyses for GHA showed osteoid matrix deposition (OM) among the granules and towards the center of the defect in centripetal direction throughout the study, with evident new bone formation at 120 days, resulting in filling 4/5 of the initial bone defect. For CG, this finding was restricted to the edges of the bone margins and formation of connective tissue on the residual area was found in all biological points. Inflammatory response on GHA was chronic granulomatous type, discrete and regressive for all biological points. Throughout the study, the CG presented mononuclear inflammatory infiltrate diffuse and regressive. Histomorphometry analyses showed that OM percentage was evident for GHA group when compared to CG group in all analyzed periods (p > 0.05). Conclusions: the biomaterial evaluated at this study showed to be biocompatible, bioactive, osteoconductive and biodegradable synchronously with bone formation.


Asunto(s)
Animales , Ratas , Materiales Biocompatibles , Regeneración Ósea , Durapatita , Alginatos
8.
J Funct Biomater ; 14(12)2023 Nov 21.
Artículo en Inglés | MEDLINE | ID: mdl-38132809

RESUMEN

Bone critical-size defects and non-union fractures have no intrinsic capacity for self-healing. In this context, the emergence of bone engineering has allowed the development of functional alternatives. The aim of this study was to evaluate the capacity of ASC spheroids in bone regeneration using a synergic strategy with 3D-printed scaffolds made from poly (lactic acid) (PLA) and nanostructured hydroxyapatite doped with carbonate ions (CHA) in a rat model of cranial critical-size defect. In summary, a set of results suggests that ASC spheroidal constructs promoted bone regeneration. In vitro results showed that ASC spheroids were able to spread and interact with the 3D-printed scaffold, synthesizing crucial growth factors and cytokines for bone regeneration, such as VEGF. Histological results after 3 and 6 months of implantation showed the formation of new bone tissue in the PLA/CHA scaffolds that were seeded with ASC spheroids. In conclusion, the presence of ASC spheroids in the PLA/CHA 3D-printed scaffolds seems to successfully promote bone formation, which can be crucial for a significant clinical improvement in critical bone defect regeneration.

9.
Biomed Mater ; 18(6)2023 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-37844570

RESUMEN

This study aimed to analyze the physicochemical and histological properties of nanostructured hydroxyapatite and alginate composites produced at different temperatures with and without sintering and implanted in rabbit tibiae. Hydroxyapatite-alginate (HA) microspheres (425-600 µm) produced at 90 and 5 °C without (HA90 and HA5) or with sintering at 1000 °C (HA90S and HA5S) were characterized and applied to evaluate thein vitrodegradation; also were implanted in bone defects on rabbit's tibiae (n= 12). The animals were randomly divided into five groups (blood clot, HA90S, HA5S, HA90, and HA5) and euthanized after 7 and 28 d. X-ray diffraction and Fourier-transform infrared analysis of the non-sintered biomaterials showed a lower crystallinity than sintered materials, being more degradablein vitroandin vivo. However, the sinterization of HA5 led to the apatite phase's decomposition into tricalcium phosphate. Histomorphometric analysis showed the highest (p< 0.01) bone density in the blood clot group, similar bone levels among HA90S, HA90, and HA5, and significantly less bone in the HA5S. HA90 and HA5 groups presented higher degradation and homogeneous distribution of the new bone formation onto the surface of biomaterial fragments, compared to HA90S, presenting bone only around intact microspheres (p< 0.01). The elemental distribution (scanning electron microscope and energy dispersive spectroscopy andµXRF-SR analysis) of Ca, P, and Zn in the newly formed bone is similar to the cortical bone, indicating bone maturity at 28 d. The synthesized biomaterials are biocompatible and osteoconductive. The heat treatment directly influenced the material's behavior, where non-sintered HA90 and HA5 showed higher degradation, allowing a better distribution of the new bone onto the surface of the biomaterial fragments compared to HA90S presenting the same level of new bone, but only on the surface of the intact microspheres, potentially reducing the bone-biomaterial interface.


Asunto(s)
Durapatita , Trombosis , Animales , Conejos , Durapatita/química , Sincrotrones , Materiales Biocompatibles/química , Cerámica , Alginatos/química
10.
Pharmaceutics ; 15(6)2023 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-37376111

RESUMEN

Magnetic nanoparticles (MNPs) have been widely used for their potential applications, mainly for the diagnosis and/or therapy (theranostic) of several diseases in the field of nanomedicine, as passive contrast agents, through the opsonization process, or active contrast agents, after their functionalization and the subsequent capture of the signal using various techniques such as magnetic resonance imaging (MRI), optical imaging, nuclear imaging, and ultrasound [...].

11.
Colloids Surf B Biointerfaces ; 223: 113174, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36746067

RESUMEN

The use of targeted alpha therapy (TAT) for bone cancer is increasing each year. Among the alpha radionuclides, radium [223Ra]Ra+2 is the first one approved for bone cancer metastasis therapy. The development of novel radiopharmaceutical based on [223Ra]Ra+2 is essential to continuously increase the arsenal of new TAT drugs. In this study we have developed, characterized, and in vitro evaluated [223Ra] Ra-nano-hydroxyapatite. The results showed that [223Ra] Ra-nano-hydroxyapatite has a dose-response relationship for osteosarcoma cells and a safety profile for human fibroblast cells, corroborating the application as a radiopharmaceutical.


Asunto(s)
Neoplasias Óseas , Nanoestructuras , Osteosarcoma , Radio (Elemento) , Humanos , Radiofármacos , Radio (Elemento)/química , Radio (Elemento)/uso terapéutico , Neoplasias Óseas/tratamiento farmacológico , Osteosarcoma/tratamiento farmacológico
12.
Bioengineering (Basel) ; 10(2)2023 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-36829732

RESUMEN

A global need exists for new and more effective contrast agents for computed tomography and traditional X-ray modalities. Among the few options available nowadays, limitations imposed by industrial production, performance, and efficacy restrict the use and reduce the potential of both imaging techniques. The use of nanomaterials as new contrast agents for X-ray and computed tomography is an innovative and viable way to increase the options and enhance performance. In this study, we evaluated eight nanomaterials: hydroxyapatite doped with zinc (Zn-HA 10%); hydroxyapatite doped with strontium (Sr-HA 10%); hydroxyapatite without thermal treatment (HA 282 STT); thermally treated hydroxyapatite (HA 212 500 °C and HA 01.256 CTT 1000 °C); hydroxyapatite microspheres (HA microspheres); gold nanoparticles (AuNP); and graphene oxide doped with copper (Cu-GO). The results showed that for both imaging modalities; HA microspheres were the best option, followed by hydroxyapatite thermally treated at 1000 °C. The nanomaterials with the worst results were hydroxyapatite doped with zinc (Zn-HA 10%), and hydroxyapatite doped with strontium (Sr-HA 10%). Our data demonstrated the potential of using nanomaterials, especially HA microspheres, and hydroxyapatite with thermal treatment (HA 01.256 CTT 1000 °C) as contrast agents for X-ray and computed tomography.

13.
J Appl Anim Welf Sci ; 26(3): 313-324, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-34279154

RESUMEN

Preference responses of cats for scratching fabrics commonly used on furniture were evaluated during four consecutive days in three Non-Governmental Organizations (NGOs) that rescue companion animals. Cats were grouped and their choices were registered at a group level (no individual identification). Daily choices for chenille, suede, synthetic leather, or waterproof grosgrain fabrics were evaluated for the cats' groups. A preference for chenille and non-preference for synthetic leather and waterproof grosgrain was found, independent of the NGO. In conclusion, although not using chenille does not assure that cats stop scratching furniture - especially if no other option to scratch is available - synthetic leather and waterproof grosgrain seem to be less attractive fabrics for these animals. Further studies are needed to investigate whether these findings apply to cats in a home scenario, when just one or a few individuals are usually present and only one type of fabric covering furniture is commonly available. Although we did not investigate the effect of providing scratching posts for these animals, we recommend such posts are available in the environment as scratching behavior is important to cats.


Asunto(s)
Conducta Animal , Diseño Interior y Mobiliario , Animales , Conducta Animal/fisiología
14.
Chemosphere ; 313: 137519, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36502913

RESUMEN

Hydroxyapatite (HA) is a biomaterial widely used in biomedical applications. Many studies have shown that ionic substituents can be incorporated into HA to produce a mineral composition more similar to natural bone tissue with more favorable biological characteristics for application in bone regeneration. However, its potentially toxic effects need to be evaluated before full approval for human use. For this purpose, an embryotoxicity test was performed on zebrafish according to OECD guideline 236. Zebrafish embryos were exposed to 1 or 3 microspheres of alginate containing nanoparticles of HA and carbonate (CHA), strontium (SrHA), and zinc-substituted HA (ZnHA) from 4 to 120 h post-fertilization (hpf). Lethality and developmental endpoints were evaluated. In addition, larval behavior at 168 hpf was also analyzed to observe whether biomaterials adversely affect optomotor and avoidance responses (neurotoxicity), as well as the oxidative stress pattern through qPCR. After 120 h exposure to all microspheres with different patterns of crystallinity, porosity, nanoparticle size, surface area, and degradation behavior, there was no mortality rate greater than 20%, indicating the non-embryotoxic character of these biomaterials. All experimental groups showed positive optomotor and avoidance responses, which means that embryo exposure to the tested biomaterials had no neurotoxic effects. Furthermore, larvae exposed to one SrHA microsphere showed a better optomotor response than the control. Furthermore, the biomaterials did not change the pattern of mRNA levels of genes related to oxidative stress even after 120 hpf. The growing number of new HA-based biomaterials produced should be accompanied by increased studies to understand the biosafety of these compounds, especially in alternative models, such as zebrafish embryos. These results reinforce our hypothesis that ion-substituted HA biomaterials do not impose toxicological effects, cause development and neuromotor impairment, or increase oxidative stress in zebrafish embryos being useful for medical devices and in the process of bone regeneration.


Asunto(s)
Nanoestructuras , Contaminantes Químicos del Agua , Animales , Humanos , Pez Cebra/metabolismo , Durapatita/toxicidad , Durapatita/metabolismo , Materiales Biocompatibles/toxicidad , Materiales Biocompatibles/metabolismo , Estrés Oxidativo , Nanoestructuras/toxicidad , Embrión no Mamífero/metabolismo , Larva , Contaminantes Químicos del Agua/toxicidad
15.
Medicina (Kaunas) ; 58(12)2022 Nov 24.
Artículo en Inglés | MEDLINE | ID: mdl-36556923

RESUMEN

Background and objectives: Calcium phosphates have been widely used as bone substitutes, but their properties are limited to osteoconduction. The association of calcium phosphates with osteoinductive bioactive molecules has been used as a strategy in regenerative medicine. Melatonin has been studied due to its cell protection and antioxidant functions, reducing osteoclastic activity and stimulating newly formed bone. This study aimed to evaluate the effect of topical application of melatonin associated with nanostructured carbonated hydroxyapatite microspheres in the alveolar bone repair of Wistar rats through histological and histomorphometric analysis. Materials and Methods: Thirty female Wistar rats (300 g) were used, divided randomly into three experimental groups (n = 10), G1: nanostructured carbonated hydroxyapatite microspheres associated with melatonin gel (CHA-M); G2: nanostructured carbonated hydroxyapatite (CHA); G3: blood clot (without alveolar filling). The animals were euthanized after 7 and 42 days of the postoperative period and processed for histological and histomorphometric evaluation. Kruskal-Wallis and Dunn's post-test were applied to investigate statistical differences between the groups at the same time point for new bone and connective tissue variables. Mann-Whitney was used to assess statistical differences between different time points and in the biomaterial variable. Results: Results showed a greater volume of residual biomaterial in the CHA-M than the CHA group (p = 0.007), and there were no significant differences in terms of newly formed bone and connective tissue between CHA and CHA-M after 42 days. Conclusions: This study concluded that both biomaterials improved alveolar bone repair from 7 to 42 days after surgery, and the association of CHA with melatonin gel reduced the biomaterial's biodegradation at the implanted site but did not improve the alveolar bone repair.


Asunto(s)
Melatonina , Ratas , Animales , Femenino , Melatonina/farmacología , Melatonina/uso terapéutico , Ratas Wistar , Materiales Biocompatibles/uso terapéutico , Durapatita , Fosfatos de Calcio/farmacología , Fosfatos de Calcio/uso terapéutico , Carbonatos
16.
Polymers (Basel) ; 14(19)2022 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-36235978

RESUMEN

Background: Bioceramic nanometer coatings have been regarded as potential substitutes for plasma-sprayed hydroxyapatite coatings, and the association with bone morphogenetic protein (BMP) is an attempt to achieve faster osseointegration to hasten oral rehabilitation. Objective: This study aimed to investigate the effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) on the osseointegration of titanium implants coated with a thin film surface of hydroxyapatite (HA). Methods: Two implants (n = 24) were placed in each white New Zealand rabbits' femur (n = 6). Implants were placed in the right femur after standard instrumentation (A and B) and in the left femur after an over-instrumentation (C and D), preventing bone-implant contact. The distal implants were installed associated with rhBMP-7 (groups B [regular instrumentation] and D [over-instrumentation]) and, also, in the absence of without BMP (control groups A [regular instrumentation] and C [over-instrumentation]). After 4 weeks, the animals were euthanized. The bone blocks containing the implants were embedded in methyl methacrylate and sectioned parallel to the long axis of the implant, which were analyzed by image segmentation. The data were analyzed using a nonparametric statistical method. Results: We observed that Group A had a mean bone formation of 35.6% compared to Group B, which had 48.6% (p > 0.05). Moreover, this group showed 28.3% of connective tissue compared to Group A, with 39.3%. In the over-instrumented groups, rhBMP-7 (Group D) showed an enhanced and significant increase in bone formation when compared with the group without rhBMP-7 (Group C). Conclusion: We concluded that the association of rhBMP-7 to thin nanostructure HA-coated implants promoted greater new bone area than the same implants in the absence of rhBMP-7, mainly in cases of over-instrumented implant sites.

17.
Medicina (Kaunas) ; 59(1)2022 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-36676670

RESUMEN

Medication-related osteonecrosis of the jaw (MRONJ) is considered as a severe adverse side effect of specific drugs such as anti-resorptive and anti-angiogenic medications. Evidence suggests that MRONJ is linked to invasive dental procedures, mainly dentoalveolar surgery. Several preventive strategies to minimize the risk of developing MRONJ have been investigated. However, no investigation has been attempted to evaluate the therapeutic effect of local drug-delivery technology as a preventive strategy protocol. The aim of this study is to evaluate the efficacy of hydroxyapatite-containing doxycycline (HADOX) in rats with high-risk MRONJ development. All the rats used in this study were divided into seven groups. Six groups of rats out of seven were exposed to two different doses of antiresorptive drug therapy for four weeks before undergoing an upper incisor extraction. After 28 days, all the animals were euthanized, and the bone blocks were processed for histological and histomorphometrical evaluation. The histomorphometric analysis confirmed that newly formed bone (NFB) was present in all groups, with significant differences. NFB in the HADOX group treated with zoledronic acid at 4% showed (28.38; C.I. 22.29-34.48), which represents a significant increase compared to HA (15.69; C.I. 4.89-26.48) (p = 0.02). A similar pattern was observed in the HADOX group treated with zoledronic acid 8% ZA treatment (p = 0.001). Conclusions: HADOX did not inhibit any bone repair and reduced early inflammatory response. Hence, HADOX could promote bone healing in patients undergoing antiresorptive drug therapy.


Asunto(s)
Osteonecrosis de los Maxilares Asociada a Difosfonatos , Conservadores de la Densidad Ósea , Ratas , Animales , Difosfonatos/efectos adversos , Ácido Zoledrónico/uso terapéutico , Conservadores de la Densidad Ósea/uso terapéutico , Doxiciclina/uso terapéutico , Osteonecrosis de los Maxilares Asociada a Difosfonatos/etiología , Osteonecrosis de los Maxilares Asociada a Difosfonatos/prevención & control , Osteonecrosis de los Maxilares Asociada a Difosfonatos/tratamiento farmacológico , Conducta de Reducción del Riesgo , Hidroxiapatitas
18.
Acta Biomater ; 120: 181-193, 2021 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-32860947

RESUMEN

The adaptation of trabecular bone microstructure to mechanical loads has been intensively investigated. However, loading-unrelated aspects of trabecular architecture remain unclear. We used synchrotron radiation-based X-ray microtomography to study the 3D microarchitecture of newly formed trabecular tissue in a defect produced in the cortical region of the rat tibia diaphysis, in the absence (7, 14, and 21 days) or the presence (21 days) of carbonated hydroxyapatite/alginate (cHA) microspheres. This work provides the first evidence that the woven bone trabecular network, formed during the healing process, displays a well-organized 3D microarchitecture consisting of nodes with 3 (3-N), 4 (4-N) and 5 (5-N) connecting trabeculae, with a mean relative abundance of (3-N)/(4-N)/(5-N) = 66/24/7, for the analyzed periods. The measured inter-trabecular angles (ITA) distribution presented a Gaussian profile, with mean value at 115° for 3-N nodes, and 105° for 4-N nodes, close to the angles of idealized 3D regular structures (120° and 109.5°, respectively). Changes in the dispersion of ITA distribution suggested that a highly symmetric trabecular fabric organized under tensegrity principles is formed early during the bone healing process. Post-implantation, cHA disaggregated into multiple fragments (~20-400 µm), stimulating osteoconduction and bone growth toward the interior of the medullary cavity. The presence of biomaterials in bone defects affected the trabecular dimensions; however, it did not interfere with the formation of geometrical motifs with topological parameters similar to those found in the sham-defects. STATEMENT OF SIGNIFICANCE: The trabecular bone microstructure enables the tissue to meet the necessary mechanical and functional demands. However, the process of trabecular microarchitecture formation during healing, in the absence or presence of a bone graft, is not yet well understood. This work demonstrated that, from the beginning of its formation in cortical bone defects, the woven-bone trabecular network is spatially organized according to the principle of tensegrity. This microarchitecture is comprised of highly symmetric geometric motifs and is an intrinsic characteristic of trabecular growth, regardless of hierarchical scale or mechanical stimulation. The addition of a biodegradable nanostructured calcium phosphate graft did not disrupt trabecular microarchitecture; however, graft biodegradation should be controlled to optimize the reproduction of intrinsic trabecular motifs throughout the defect.


Asunto(s)
Diáfisis , Tibia , Animales , Densidad Ósea , Regeneración Ósea , Huesos , Hueso Cortical/diagnóstico por imagen , Diáfisis/diagnóstico por imagen , Ratas , Tibia/diagnóstico por imagen
19.
J Funct Biomater ; 11(4)2020 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-33291525

RESUMEN

Many biomaterials are used for Bone Morphogenetic Proteins (BMPs) delivery in bone tissue engineering. The BMP carrier system's primary function is to hold these growth factors at the wound's site for a prolonged time and provide initial support for cells to attach and elaborate the extracellular matrix for bone regeneration. This study aimed to evaluate the nanostructured carbonated hydroxyapatite microspheres (nCHA) as an rhBMP-2 carrier on rats calvaria. A total of fifteen male Wistar rats were randomly divided into three groups (n = 5): clot (control group), rhBMP-2 associated with collagen membrane (COL/rhBMP-2) or associated with the microspheres (nCHA/rhBMP-2). After 45 days, the calvaria defect samples were evaluated through histological, histomorphometric, and SR-µCT analyses to investigate new-formed bone and connective tissue volume densities. The descriptive histological analysis showed that nCHA/rhBMP-2 improved bone formation compared to other groups. These results were confirmed by histomorphometric and SR-µCT analysis that showed substantially defect area filling with a higher percentage of newly formed (36.24 ± 6.68) bone than those with the COL/rhBMP-2 (0.42 ± 0.40) and Clot (3.84 ± 4.57) (p < 0.05). The results showed that nCHA is an effective carrier for rhBMP-2 encouraging bone healing and an efficient alternative to collagen membrane for rhBMP-2 delivery.

20.
J Mech Behav Biomed Mater ; 109: 103817, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32543392

RESUMEN

The aim of this study was to fabricate and characterize dental composites containing hydroxyapatite nanoparticles (HApNPs). Four dental composites were produced from the same organic matrix (70 wt% Bis-GMA and 30 wt% TEGDMA), with partial replacement of BaBSi particles (65 wt%) by HApNPs in the following concentrations (wt%): E0 (0) - control, E10 (10), E20 (20) and E30 (30). Ca2+ and PO43- release was evaluated in solutions with different pHs (4, 5.5, and 7) using atomic emission spectroscopy with microwave-induced nitrogen plasma while the enamel remineralization potential was evaluated in caries-like enamel lesions induced by S. mutans biofilm using micro-CT. The following properties were characterized: degree of conversion (DC%), microhardness (KHN), flexural strength (FS), elastic modulus (EM) and translucency (TP). The higher the HApNPs content, the higher the Ca2+ and PO43- release. The ions release was influenced by pH (4 > 5.5 > 7) (p < 0.05). All composites loaded with HApNPs were able to remineralize the enamel (E30 = E20 > E10) (p < 0.05). Contrarily, E0 was not able of recovering the enamel mineral loss. E0 and E10 presented highest DC%, while E20 and E30 showed similar and lowest DC%. KHN and FS were decreased with the addition of HApNPs, while EM was not influenced by the incorporation of HApNPs. E10 presented statistically similar TP to E0, while this property decreased for E20 and E30 (p < 0.05). Incorporation of HApNPs into dental composites promoted enamel remineralization, mainly at potentially cariogenic pH (= 4), while maintained their overall performance in terms of physicomechanical properties.


Asunto(s)
Durapatita , Nanopartículas , Bisfenol A Glicidil Metacrilato , Resinas Compuestas , Ensayo de Materiales , Ácidos Polimetacrílicos
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