Please read the abstract in the section 00front of this document / Dissertation (MChD (Periodontics and Oral Medicine))--University of Pretoria, 2007. / Oral Pathology and Oral Biology / unrestricted

Orientador: Jose Angelo Camilli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-07T15:55:04Z (GMT). No. of bitstreams: 1 Silva_RosaneVieirada_D.pdf: 3119168 bytes, checksum: f66eb3f659f48068db93e8a9062870da (MD5) Previous issue date: 2006 / Resumo: Procedimentos que permitem a reconstrução e acelerem o reparo de fraturas ósseas são de grande importância clínica. Sendo assim, considerando as vantagens oferecidas pelos biomateriais como substitutos aos enxertos ósseos autógenos e os efeitos positivos do laser de baixa energia no processo de regeneração óssea, as propostas do presente trabalho foram estudar a contribuição do laser de baixa energia no processo de reconstrução de falhas ósseas tratadas com enxerto ósseo autógeno, assim como, analisar "in vitro" e "in vivo" a eficácia da cerâmica de fosfato de cálcio como possível substituta aos enxertos ósseos autógenos. O resultado da laserterapia na dosagem estabelecida em nosso trabalho demonstrou que a mesma acelerou a osteogênese na área de enxertia somente nos primeiros períodos do tratamento e esse efeito foi dose dependente.Enquanto isso, o estudo "in vivo" da biocerâmica demonstrou que o implante foi tão eficiente quanto o enxerto ósseo autógeno no processo de reconstrução da falha óssea. No estudo "in vitro", os osteoblastos humanos apresentaram boa interação com a cerâmica, apresentando maior preferência pelas superfícies mais irregulares do material / Abstract: Procedures that allow the reconstruction and speed up the bone repair are of great clinical importance. Being thus, considering the advantages offered for the biomaterials as substitute to the autogenous bone graft and the positive effect of the low-power-laser in the process bone regeneration, the proposals of the present work had been to study the contribution of the low-power-laser in the process of reconstruction of bone defect treated with autogenous bone graft, as well as, to analyze "in vitro" and "in vivo" the efficiency of calcium phosphate ceramic as possible substitute to the autogenous bone graft. The result demonstrated that laser irradiation at the grafted site stimulated osteogenesis during the initial stages of the healing process in na skull defect and this effect was dose dependent. While this, the "in vivo" study of the bioceramic demonstrated that the implantation was so efficient how much autogenous graft in the bone reconstruction process. In the study "in vitro", the human osteoblast had presented' good interaction with ceramics, presenting bigger preference for the surfaces most irregular of the material / Doutorado / Anatomia / Doutor em Biologia Celular e Estrutural

Orientador: Jose Ricardo de Albergaria-Barbosa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-01T00:32:36Z (GMT). No. of bitstreams: 1 Rabelo_LuisRaimundoSerra_D.pdf: 7546603 bytes, checksum: ab098403b9103521ab84bb486ab82543 (MD5) Previous issue date: 2001 / Resumo: O objetivo deste trabalho foi realizar um estudo comparativo de diferentes materiais preenchimentos ósseos sobre o processo de regeneração óssea guiada em defeitos perimplantares do tipo fenestração, realizados em fêmur de coelhos. Defeitos circulares de 2,6mm de diâmetro foram confeccionados na face medial do fêmur, de forma a expor a superfície do implante. Foram colocados 40 implantes de titânio de 6mm de comprimento por 2,6mm de diâmetro, bilateralmente, em fêmur de coelhos. Os defeitos foram preenchidos, de acordo com o grupo estudado, com: vidro bioativo, matriz óssea liofilizada de origem humana, osso autógeno e preenchimento por coágulo, que serviu como controle do experimento. Todos os defeitos, após preenchimento, foram protegidos por membrana de celulose. Os animais foram sacrificados após períodos de 3 e 6 semanas, quando blocos ósseos contendo os implantes, foram descalcificados e processados para posterior análise histológica em microscopia óptica comum e análise histométrica. Os dados histométricos revelaram melhores resultados de formação óssea no período de 3 semanas para os grupos Osso autógeno e Osso liofilizado (37,8% e 37,1%, respectivamente), e não apresentaram diferenças estatísticas significantes entre si. No período de 6 semanas o grupo Osso autógeno apresentou os maiores resultados de formação óssea (64,1%) / Abstract: The purpose of this study was compare the bone healing after different bone grafting materiais in bone tissue regeneration around implants in rabbit' s femur. Forty 6 x 2.6mm titanium implants were placed, bilaterally, in the femur of twenty New Zealand rabbits. Circular defects (2.6mm in diameter) were created at mesial of each femur, in order to expose implant threads. Defects were filled with human demineralized freeze-dried bone (Dembone), rabbit bone-chips autografts (autogenous bone) , bioactive glass granules (Perioglas) and control group filled with blood clot (control). Ali defects were protected with cellulose membranes. Rabitts were sacrificed 3 and 6 weeks after graft placement, the specimens were cut into block sections on a low speed bur and submited to histologic and histometric analysis. Among the graft materiais, autogenous bone and human demineralized freeze-dried bone provided the greatest amount of bone formation (37,8% and 37,1%, respectively) after 3 weeks of healing, with no statistically signifcant difference between them. After 6 weeks, autogenous bone provided the densest and greatest amount bone formation (64,1 %). Between 3 and 6 weeks, the greatest amount of bone formation was provided by autogenous bone grafts, and the control group showed a lesser quantity of bone formation as compared to the grafted groups / Doutorado / Cirurgia / Doutor em Clínica Odontológica

Devido as limitações relacionadas ao emprego do enxerto autólogo, o uso dos biomateriais poliméricos naturais tornou-se uma opção viável em terapias regenerativas do tecido ósseo. O objetivo desse trabalho é avaliar de forma qualitativa e quantitiva a contribuição da membrana de elastina utilizada isoladamente ou em associação a hidroxiapatita e proteína morfogenética óssea, no reparo de defeitos ósseos no crânio de ratos. Foram utilizados 49 ratos (Rattus norvegicus, Wistar), machos, com peso aproximado de 330 gramas e 4 meses de idade. Os animais foram submetidos ao procedimento cirúrgico para a criação do defeito ósseo no osso parietal esquerdo e divididos em 7 grupos com 7 animais cada. Os grupos foram implantados com os seguintes bioamateriais: grupo 1 controle (G1-C) sem implante, grupo 2 (G2-E24h) membrana de elastina 24 h, grupo 3 (G3-E24h/HA) membrana de elastina 24 h com hidroxiapatita, grupo 4 (G4-E24h/BMP) membrana de elastina 24 h com proteína morfogenética óssea, grupo 5 (G5-E96h) membrana de elastina 96 h, grupo 6 (G6-E96h/HA) membrana de elastina 96 h com hidroxiapatita, grupo 7 (G7-E96h/BMP) membrana de elastina 96 h com proteína morfogenética óssea. Após a morte indolor induzida em 6 semanas, as calotas cranianas foram retiradas para análise macroscópica, radiográfica, histológica e morfométrica. As análises macroscópicas, radiográficas e histológicas demonstraram a biocompatibilidade dos biomateriais utilizados. As médias e desvios-padrão do volume percentual relativo de osso neoformado nos defeitos cranianos dos grupos G1 a G7 foram 7,87±2,53; 24,01±0,55; 9,59±1,27; 31,31±6,37; 19,77±2,62; 7,31±2,43; 43,25±3,72, respectivamente. Os biomateriais mostraram-se biocompatíveis e o grupo 7 (G7-E96h/BMP) resultou na maior neoformação óssea. / Due to the limitations related to the use of autologous grafts, the use of natural polymeric biomaterials has become a viable option in regenerative therapies of bone tissue. The objective of this dissertation is to evaluate in qualitative and quantitative way the contribution of the elastin matrice used alone or in combination with hydroxyapatite and bone morphogenetic protein in the repair of bone defects in the skull of rats. Were use 49 Mices (Rattus norvegicus, Wistar), weighting approximately 330 grams and 4 months of age, were used. The animals were submitted to the surgical procedure to create the bone defect in the left parietal bone and divided into 7 groups with 7 animals each. The groups were implanted with the following biomaterials: group 1 control (G1-C) without biomaterial, group 2 (G2-E24h) 24 h elastin membrane, group 3 (G3-E24h/HA) 24 h elastin membrane with hydroxyapatite, Group 4 (G4-E24h/BMP) elastin membrane 24 h with bone morphogenetic protein, group 5 (G5-E96h) elastin membrane 96 h, group 6 (G6- E96h/HA) elastin membrane 96 h with hydroxyapatite, group 7 (G7-E96h/BMP) 96 h elastin membrane with bone morphogenetic protein. After painless death induced at 6 weeks, the skull caps were removed for macroscopic, radiographic, histological and morphometric analysis. Macroscopic, radiographic and histological analysis demonstrated the biocompatibility of the biomaterials used. The mean and standard deviations of the relative percentage volume of newly formed bone in the cranial defects of the G1 to G7 groups were 7,87±2,53; 24,01±0,55; 9,59±1,27; 31,31±6,37; 19,77±2,62; 7,31±2,43; 43,25±3,72, respectively. The implanted biomaterials were shown to be biocompatible and the group 7 (G7-E96h/BMP) resulted with greater bone neoformation.

A regeneração óssea requer não somente um arcabouço, mas também uma seqüência de eventos biológicos regulados por múltiplos fatores. No presente, o plasma rico em plaquetas (PRP) consiste numa importante fonte de fatores de crescimento. O objetivo deste trabalho foi avaliar a eficácia da associação de vidro bioativo e PRP na reparação de defeitos cirúrgicos realizados no osso parietal de coelhos. Para tanto, foram utilizados dez coelhos da raça Nova Zelândia, sendo que em cada animal foram confeccionados dois defeitos de 8 mm nos ossos parietais, os quais receberam tratamentos diferentes: a) grupo 1 vidro bioativo (tratamento VB) e coágulo sangüíneo (tratamento CO); b) grupo 2 vidro bioativo + PRP (tratamento VB + PRP) e PRP isolado (tratamento PRP). Os animais foram sacrificados após 12 semanas, sendo os espécimes submetidos a estudo radiográfico (densidade em tons de cinza), histológico (coloração de hematoxilina e eosina) e histomorfométrico (planimetria por contagem de pontos). Os dados de densidade radiográfica e histomorfometria foram submetidos separadamente ao teste de análise de variância (ANOVA) e ao teste de Tukey (5%). Nos tratamentos PRP + VB e PRP observou-se maior densidade óssea radiográfica e maior neoformação óssea histomorfométrica, não havendo diferença estatística entre os mesmos. Não houve diferença estatística entre os tratamentos VB e CO em relação à densidade óssea e neoformação óssea histomorfométrica. Histologicamente, a neoformação óssea foi maior nos tratamentos PRP + VB e PRP, destacando-se o PRP + VB. Portanto, o PRP favoreceu a reparação óssea e o VB não favoreceu o reparo ósseo isoladamente e não alterou a reparação óssea obtida pelo PRP. / Bone regeneration not only requires a scaffold, but also a sequence of biological events regulated by multiple factors. Nowadays, the platelet-rich plasma (PRP) consists an important source of growth factors. The aim of this study was to evaluate the effectiveness of the association of bioactive glass and PRP in the repairing of surgical defects realized in the parietal bone of rabbits. Ten rabbits New Zealand were used, and on each animal two defects of 8 mm in the parietal bones had been confectioned, which had received different treatments: a) group 1 - bioactive glass (treatment VB) and coagulum (treatment CO); b) group 2 - bioactive glass + PRP (treatment VB + PRP) and isolated PRP (treatment PRP). The animals were sacrificed after 12 weeks, and the specimens were submitted to radiographic (density grey degrees), histological (hematoxilin and eosin coloration) and histomorfometrical (planimetry for counting of points) analysis. The results of radiographic density and histomorfometric were submitted separately to the test of analysis of variance (ANOVA) and Tukeys test (5%). In the treatments PRP + VB and PRP major radiographic bone density and major histomorfometric new bone formation was observed, without statistical difference between them. It did not have statistical difference between treatments VB and CO in relation to the bone density and histomorfometric new bone formation. Histologically, the new bone formation was bigger in the treatments PRP + VB and PRP, emphasizing PRP + VB. Therefore, the PRP supported the bone repairing and the VB does not supported the bone repair separately and does not modified the bone repairing gotten by the PRP.

O tecido ósseo é considerado um tecido complexo e possui alta capacidade de reparação espontânea quando lesionado. Entretanto, em algumas patologias esta capacidade pode estar comprometida por diversos fatores extrínsecos e intrínsecos ao organismo. Em decorrência de sua capacidade plástica, o uso de células-tronco para terapia celular regenerativa tem se tornado uma importante ferramenta no tratamento de lesões ósseas e de doenças decorrentes da perda da densidade mineral óssea (DMO). Em contraste, o uso da Proteína Morfogenética Óssea (BMP) ganhou grande destaque pela sua eficácia em tratar doenças ósseas de caráter crônico e, quando associadas a células-tronco, trouxe um melhor resultado para tais desordens. Assim, o presente trabalho teve como objetivo avaliar a associação de célula-tronco mesenquimal de medula óssea (MSC Mesenchymal Stem Cells) e BMP-7 na regeneração óssea a partir de defeito ósseo induzido na calvária murina no 60º dia de tratamento. Foram realizadas imagens radiográficas da calvária e, após os dias estipulados, o material foi coletado para análise de microscópica. Os dados obtidos sugerem que o modelo de regeneração óssea proposto foi apropriado para avaliar a resposta terapêutica usando MSC e BMP-7, onde o cultivo e pré-diferenciação de MSC com BMP-7 produziu melhores resultados do que os outros tratamentos realizados / Bone tissue is considered a complex tissue and has high capacity for spontaneous recovery when injured. However, in some conditions this capacity can be compromised by several extrinsic and intrinsic factors to the body. Due to its plastic capacity, the use of stem cells for regenerative cell therapy has become an important tool in the treatment of bone injuries and diseases resulting from loss of bone mineral density (BMD). In contrast, the use of Bone Morphogenetic Protein (BMP) has gained wide attention for its effectiveness in treating bone diseases were chronic and brought a better outcome for such disorders when associated with stem cells. Thus, the present study aimed to evaluate the association of bone marrow mesenchymal stem cells (MSC) and BMP-7 in bone regeneration from bone defects induced in murine calvaria on the 60th day of treatment. Radiographic images of the calvaria were performed and after the stipulated days the material was collected for microscopic essays. The data obtained suggest that the proposed model of bone regeneration was appropriate to assess the therapeutic response using MSC and BMP-7, where the pre cultivation and differentiation of MSCs with BMP-7 produced better results than the other treatments performed.

Gene therapy using non-viral vectors that are safe and efficient at transfecting target cells is an effective approach to overcome the shortcomings of delivery of growth factors in protein form. The objective of this study was to develop and test a non-viral gene delivery system for bone regeneration utilizing a collagen scaffold carrying polyethylenimine (PEI)-plasmid DNA (pDNA) complexes. Two different pDNA were used: pDNA encoding platelet derived growth factor-B (PDGF-B) and pDNA encoding vascular endothelial growth factor (VEGF). The complexes were fabricated at an amine (N) to phosphate (P) ratio of 10 and then characterized for size, surface charge, as well as in vitro cytotoxicity and transfection efficacy in human bone marrow stromal cells (BMSCs). The influence of the PEI-pPDGF-B complex-loaded collagen scaffold on cellular attachment and recruitment was evaluated in vitro using microscopy techniques. The in vivo regenerative capacity of the gene delivery system, using PEI-pPDGF-B and PEI-pVEGF complexes, was assessed in 5 mm diameter critical-sized calvarial defects in Fisher 344 rats. A different biomaterial, chitosan, loaded with copper was also evaluated in vivo. The complexes were ∼100 nm in size with a positive surface charge. Complexes prepared at an N/P ratio of 10 displayed low cytotoxicity as assessed by a cell viability assay. High magnification scanning electron microscopy imaging demonstrated the recruitment and attachment of BMSCs into the collagen scaffold containing PEI-pPDGF-B complexes. Confocal microscopy revealed significant proliferation of BMSCs on PEI-pPDGF-B complex-loaded collagen scaffolds compared to empty scaffolds. In vivo studies showed significantly higher new bone volume/total volume (BV/TV) % in calvarial defects treated with the PEI-pPDGF-B complex-activated collagen scaffolds following 4 weeks of implantation when compared to the other treatment groups. Together these findings suggest that non-viral PDGF-B gene-activated collagen scaffolds effectively promote bone regeneration and are an attractive gene delivery system with significant potential for clinical translation.

Orientador: Morgana Rodrigues Guimarães Stabili / Resumo: Curcumin é um composto ativo derivado da planta Curcuma longa que exibe uma variedade de atividades biológicas, potencial anti-inflamatório e imunomodulatório, que pode ser associado ao tratamento de uma série de condições, como doenças inflamatórias intestinais, artrite reumatoide, câncer, diabetes e periodontite. Recentemente, a literatura também tem demonstrado o potencial do composto sobre o reparo ósseo, entretanto, os dados ainda são contraditórios. O objetivo deste estudo é avaliar o efeito da administração tópica do curcumin veiculado em nanopartículas de PLGA sobre a formação/reparo ósseo de defeitos críticos in vivo, e investigar seu potencial biológico in vivo e in vitro. Defeitos ósseos confeccionados na calvária de ratos machos foram preenchidos com solução salina (controle), curcumin nanoparticulado 0,05mg/ml ou veículo utilizado na diluição do composto (nanopartícula vazia) por 7, 14 e 28 dias. A fração de volume ósseo no interior do defeito nos diferentes grupos foram avaliados por microtomografia óssea (μCT); expressão e imunolocalização dos marcadores do turnover tecidual (RANKL, OPG, PCNA e RUNX2) foram investigados por imuno-histoquímica, enquanto as características teciduais do tecido neoformado foram observadas através da análise histológica descritiva e estereometria. In vitro, o potencial do curcumin nanoparticulado em estimular a diferenciação osteogênica de células estromais derivadas da medula óssea (BMSCs) de ratos foi avaliado determinando-se a at... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Curcumin is an active compound derived from the Curcuma longa plant that exhibits a variety of biological activities, anti-inflammatory and immunomodulatory potential, which can be associated with the treatment of a number of conditions, such as inflammatory bowel diseases, rheumatoid arthritis, cancer, diabetes and periodontitis. Recently, the literature has also demonstrated the potential of the compound on bone repair, however, the data are still contradictory. The aim of this study is to evaluate the effect of topical administration of curcumin-loaded PLGA nanoparticles on bone formation / repair of critical defects in vivo, and to investigate its biological potential in vivo and in vitro. Bone defects made in the calvaria of rats were filled with saline solution (control), nanoparticulate curcumin 0,05mg/ml, or vehicle used in the dilution of the compound (empty nanoparticle) for 7, 14 and 28 days. The fraction of bone volume within the defect in the different groups was assessed by microcomputed tomography (μCT); expression and immunolocation of tissue turnover markers (RANKL, OPG, PCNA and RUNX2) were investigated by immunohistochemistry, while the tissue characteristics of the newly formed tissue were observed through descriptive histological analysis and stereometry. In vitro, the potential of nanoparticulate curcumin in stimulating osteogenic differentiation of rat bone marrow-derived stromal cells (BMSCs) was assessed by determining the activity of alkaline phospha... (Complete abstract click electronic access below) / Mestre

Often caused by trauma or tumor removal, large bone defects frequently result in delayed or non-union. The current gold standard for treatment is autograft. However, due to limitations, such as the size and location of the defect, these cannot always be utilized. A common alternative to autograft is the use of BMP-2 with a collagen scaffold, however, this treatment is limited by numerous side effects. In recent years, genetic materials such as microRNAs (miRNAs) have offered possible alternative therapies. MiRNAs are small non-coding RNA molecules that generally range from 20-24 nucleotides, serve as repressors of gene expression, and are involved in a wide range of biological activities. Their functions can be inhibited or upregulated by delivering antagomiRs or miRNA mimics, respectively. Two miRNAs involved in bone regeneration are of particular interest in this study, miR-26a and miR-133a. Previous studies demonstrated miR-26a is involved in osteoblastic differentiation and miR-133 is a negative regulator of Runx2, the key transcription factor of osteogenesis. Therefore, we hypothesized the delivery of miR-26a and antagomiR-133a will increase bone formation in critical-sized bone defects. The research outlined in this thesis investigates the healing efficacy of these genetic cargos delivered by novel peptide nanoparticles, RALA, soak loaded into a collagen-hydroxyapatite scaffold. vi To test this hypothesis, scaffolds soak-loaded with RALA/microRNA were implanted into calvarial defects in Wistar Rats. The defects were then left to heal for 8 weeks and were longitudinally monitored using micro-computed tomography (μCT). At 8 weeks, rats were euthanized and calvaria tissue was harvested for histological analysis. The μCT data demonstrates that the scaffolds with microRNAs show promise as a novel therapy for bone defects. The histological analysis showed the treatments promote healing by normal bone formation activity. While there was no statistical difference (p ≥ 0.11276) between groups for the healing variables, this is believed to be due to the small sample size and low power (60%). All of the miRNA treatment groups had samples with considerably higher healing responses than the gene-free group. In conclusion, the findings of this study support the use of this cell-free implant system as a potential novel clinical therapy, as an alternative to bone grafting, for treating large bone defects.

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