Thesis (Ph.D.)--Ohio University, March, 2005. / Title from PDF t.p. Includes bibliographical references (p. 118-125)

Thesis (M.S.)--Baylor University, 2008. / Includes bibliographical references (p. 63-64).

Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Dr. Marc E. Levenston, Committee Chair ; Dr. Lawrence J. Bonassar, Committee Member ; Dr. Robert E. Guldberg, Committee Member ; Dr. William J. Koros, Committee Member ; Dr. Christopher S. Lynch, Committee Member.

Orientador: Eliana Aparecida de Rezende Duek / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T07:55:59Z (GMT). No. of bitstreams: 1 Esposito_AndreaRodrigues_M.pdf: 4037379 bytes, checksum: 0972d6543df2aa3ece0f74e93c30dfc4 (MD5) Previous issue date: 2010 / Resumo: A engenharia tecidual utilizando células fibrocartilaginosas e arcabouços poliméricos representa uma alternativa para o tratamento de lesões do menisco. Neste estudo, arcabouços de PLDLA/PCL-T (90/10) contendo sacarose (50% m/v) foram obtidos por evaporação de solvente. Fibrocondrócitos provenientes do menisco de coelhos foram isolados e semeados diretamente sobre os arcabouços. Estudos in vitro demonstraram que o arcabouço não apresentou citotoxicidade e permitiu a adesão e o crescimento de fibrocondrócitos, bem como manutenção da síntese de matriz extracelular colágena nos tempos de 7, 14, 21 e 28 dias de cultivo. Os implantes de PLDLA/PCL-T foram realizados no menisco medial do joelho de 20 coelhos, após a meniscectomia total, obtendo-se três tratamentos: arcabouço com pré-cultivo celular por 21 dias, arcabouço sem células e controle. Após 12 e 24 semanas, as análises histológicas dos "neomeniscos" apresentaram a formação de fibrocartilagem nos implantes com os arcabouços. A presença de tecido fibrocartilaginoso maduro com fibras colágenas organizada foi predominantemente observada nos implantes realizados com os arcabouços pré-cultivados em comparação com os implantes sem células após 24 semanas. Este estudo demonstrou que a regeneração de uma importante estrutura fibrocartilaginosa pode ser alcançada utilizando arcabouço polimérico biorreabsorvível e células alógenas dentro dos princípios da engenharia de tecidos / Abstract: Tissue engineering of meniscus using fibrochondrocyte-like cells and bioreabsorbable polymer scaffolds could be an alternative option to treat meniscus injury. In this study PLDLA/PCL-T (90/10) scaffolds containing sucrose (50% m/v) were obtained by casting. Allogeneic meniscal cells were isolated from rabbit meniscus and directly seeded onto the scaffolds. In vitro studies showed that scaffolds did not present cytotoxicity and allowed fibrochondrocytes adhesion and ingrowth, as well as collagen extracellular matrix synthesis at 7, 14, 21 and 28 days of culture. The PLDLA/PCL-T implants were performed in the medial meniscus of 20 rabbit knee after total meniscectomy, obtained three treatments: pre-seeded 21 days scaffold, unseeded scaffold and control. Histology analysis of "neomenisci" sections at 12 and 24 weeks revealed the presence of fibrocartilage in the polymer implants. The presence of mature fibrocartilaginous tissue with organized collagen fibers was predominantly observed in the pre-cultured implants compared to unseeded implants after 24 weeks. This study demonstrates that regeneration of an important fibrocartilaginous structure can be achieved using a bioreabsorbable polymer scaffold and allogeneic cells-based tissue engineering approaches / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Orientador: Eliana Aparecida de Rezende Duek / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-25T20:37:05Z (GMT). No. of bitstreams: 1 Cabrera_AndreaRodriguesEsposito_D.pdf: 56970103 bytes, checksum: 0ab20c99ece698f3eb8622ada3260515 (MD5) Previous issue date: 2014 / Resumo: Estruturas tridimensionais têm sido obtidas por diversas técnicas e representam um importante enfoque no desenvolvimento de suportes porosos para a engenharia tecidual. O objetivo deste trabalho foi desenvolver e caracterizar arcabouços tridimensionais porosos de poli(L-co-D,L ácido lático-co-trimetileno carbonato), PLDLA-co-TMC, obtidos pela técnica de deposição de fibras 3D. Arcabouços do terpolímero PLDLA-co-TMC, nas proporções 70:30 e 50:50, foram obtidos e caracterizados por microscopia eletrônica de varredura, cromatografia de permeação em gel, calorimetria exploratória diferencial, análise termogravimétrica, ensaio mecânico de compressão e estudo de degradação in vitro, os quais evidenciaram suas características amorfas, geometria cilíndrica e poros interconectados. O estudo de degradação in vitro, apresentou expressiva perda das propriedades mecânicas compatíveis com queda na massa molar, acompanhada de alterações na morfologia. Avaliou-se a histocompatibilidade da associação de células-tronco mesenquimais provenientes da medula óssea de coelhos e arcabouços de PLDLA-co-TMC (70:30), obtidos pelo método de evaporação de solvente com adição de sacarose (50%), na regeneração do menisco. Nove coelhos Nova Zelândia foram submetidos a meniscectomia medial total, obtendo-se três tratamentos: implante do arcabouço de PLDLA-co-TMC com pré-cultivo celular, implante de arcabouço de PLDLA-co-TMC puro (sem células) e controle negativo (defeito sem implante). Após 24 semanas, os resultados evidenciaram a presença de fibrocartilagem nos animais tratados com arcabouço polimérico. Contudo, a regeneração obtida com arcabouços de PLDLA-co-TMC pré-cultivados com células-tronco mesenquimais apresentou-se semelhante ao tecido fibrocartilaginoso maduro do menisco normal, tanto macroscopicamente quanto histologicamente. Este estudo demonstrou a eficácia do arcabouço de PLDLA-co-TMC (70:30) na regeneração fibrocartilaginosa e o potencial do pré-cultivo de células mesenquimais na engenharia tecidual, sem o uso de fatores de crescimento. Conclui-se que os polímeros biorreabsorvíveis representam uma alternativa promissora para a regeneração tecidual / Abstract: Three-dimensional structures have been obtained by various techniques and are an important focus in the development of porous scaffolds for tissue engineering. The aim of this study was to develop and characterize three-dimensional porous scaffolds of poly (L-co-D, L lactide-co-trimethylene carbonate), PLDLA-co-TMC, obtained by 3D fiber deposition technique. The PLDLA-co-TMC terpolymer scaffolds, 70:30 and 50:50, were obtained and characterized by scanning electron microscopy, gel permeation chromatography, differential scanning calorimetry, thermal gravimetric analysis, compression mechanical testing and study on in-vitro degradation, which exhibited its amorphous characteristics, cylindrical geometry and interconnected pores. The in-vitro degradation study showed significant loss of mechanical properties compatible with a decrease in molar mass, accompanied by changes in morphology. The histocompatibility association of mesenchymal stem cells from rabbits bone marrow, and PLDLA-co-TMC (70:30) scaffolds, obtained by casting with sucrose (50%), was evaluated in the meniscus regeneration, proving the potential of cell culture at in vivo tissue regeneration. Nine New Zealand rabbits underwent total medial meniscectomy, yielding three treatments: implantation of the seeded PLDLA-co-TMC scaffold, implantation of the unseeded PLDLA-co-TMC and negative control (defect without any implant). After 24 weeks, the results revealed the presence of fibrocartilage in the animals treated with polymer. However, the regeneration obtained with the seeded PLDLA-co-TMC scaffolds with mesenchymal stem cells had become intimal to mature fibrocartilaginous tissue of normal meniscus both macroscopically and histologically. This study demonstrated the effectiveness of the PLDLA-co-TMC (70:30) scaffold in meniscus regeneration and the potential of mesenchymal stem cells in tissue engineering, without the use of growth factors. It is concluded that bioresorbable polymers represent a promising alternative for tissue regeneration / Doutorado / Materiais e Processos de Fabricação / Doutora em Engenharia Mecânica

Orientadores: Cecilia Amelia de Carvalho Zavaglia, Vanessa Petrilli Bavaresco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-20T08:05:10Z (GMT). No. of bitstreams: 1 Wataya_CelioHitoshi_D.pdf: 3496514 bytes, checksum: a0aa09bccd8fc730f8ee1b6d7c5f5f37 (MD5) Previous issue date: 2012 / Resumo: O menisco como qualquer outro órgão, possui sua importância no funcionamento total do corpo humano. O tratamento para as lesões do menisco tem sido substituído pelo reparo, entretanto, conforme a gravidade da lesão torna-se inevitável a meniscectomia (cirurgia do menisco). Diante desta situação propôs-se desenvolver uma prótese que substitua o menisco lesionado, que possua suas características dimensionais, bem como suas propriedades mecânicas e tribológicas. A utilização da tecnologia da prototipagem rápida foi fundamental para se alcançar efetivamente o objetivo proposto. O material selecionado para a obtenção dessa prótese foi o poli(álcool vinílico) (PVA), por ser um polímero de baixo custo de produção, fácil obtenção e boas características para ser utilizado como um biomaterial. Os resultados dos ensaios mecânicos confirmaram a eficácia desse material. Valores como módulo de compressão 37,4 MPa (± 1,74), o módulo de fluência a indentação E = 3,6 MPa (±0,6); módulo de tensão e deformação, respectivamente iguais a 'SIGMA' = 3,2 MPa (±0,3) e ? = 148,4% (±39), evidenciam a possibilidade de utilização do PVA também como substituto do menisco humano. Outros ensaios também foram realizados como: ensaio in vitro e in vivo, tribológico e a Calorimetria Diferencial de Varredura (DSC), com resultados favoráveis a esse fim. Para a obtenção do menisco de PVA nas dimensões do menisco do paciente utilizou-se a tecnologia da prototipagem rápida (PR), primeiro para se obter o molde do menisco e depois então, o menisco por envasamento da solução de PVA no molde. Dois detalhes foram fundamentais para se chegar ao produto final, o primeiro foi o tratamento computacional dado à imagem de tomografia do joelho utilizando-se de programas livres como Invesalius e Rhinoceros e o segundo foi o uso do reticulante físico, o reagente orgânico dimetilsulfóxido (DMSO) / Abstract: The meniscus like any other organ, has its importance in the total functioning of the human body. The treatment for meniscal injuries has been replaced by the repair, however, according to the severity of the injury becomes inevitable meniscectomy (meniscus surgery). In this situation it was proposed to develop a prosthesis to replace the injured meniscus, which have their dimensional characteristics as well as their mechanical and tribological properties. The use of rapid prototyping technology was essential to effectively achieve the proposed objective. The material selected for obtaining a prosthesis is poly (vinyl alcohol) (PVA), being a polymer of low production cost, and easy to obtain good characteristics for use as a biomaterial. The results of mechanical tests have confirmed the effectiveness of this material. Values like compression module 37.4 MPa (± 1.74), the modulus of creep indentation E = 3,6 MPa (± 0.6), tensile modulus and strain, respectively equal to ' SIGMA' = 3.2 MPa (± 0.3) and ? = 148.4% (± 39) show the possibility of use of PVA as well as replacement of the meniscus human. Other tests were also conducted as in vitro and in vivo tribological and Differential Scanning Calorimetry (DSC), with results favorable to that end. To obtain the meniscus of PVA in the dimensions of the meniscus of the patient if the technology used rapid prototyping (RP), first to obtain the mold of the meniscus after then, the meniscus by filling the PVA solution in the mold. Two things were essential to reach the final product, the first treatment was given to computer tomography imaging of the knee using free programs like Rhinoceros and InVesalius and the second was the use of physical crosslinking, the organic reagent dimethyl sulfoxide (DMSO) / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

Post-traumatic osteoarthritis (PTOA) of the knee is a complication resulting from direct injury to the joint, such as anterior cruciate ligament and meniscus tears, and accounts for approximately 12% of all OA cases. The economic and clinical impact of PTOA is also greater than idiopathic OA, as patients are younger and often more active, requiring treatments for symptomatic OA over a greater fraction of their lifetime. A common strategy to manage pain and inflammation associated with PTOA is the intraarticular administration of corticosteroids. However, these injections are limited due to the requirement of high-doses imposed by synovial joint clearance rates and their resulting systemic side effects. In addition, currently used broad-spectrum corticosteroids are palliative and not curative, stemming from incomplete knowledge of specific mechanisms that drive cartilage degeneration and other joint pathologies. Thus, most patients with PTOA eventually undergo surgical procedures such as osteochondral graft transplantation for focal defects and in more severe cases, total knee arthroplasty. As such, the studies presented in this dissertation (i) offer specific insights into mechanisms by which traumatic injury can drive joint degeneration and (ii) present novel strategies to modulate joint responses to pathological factors by leveraging sustained drug-delivery platforms. In Part I, mechanistic assessments of human cartilage and synovium responses to insults are conducted to identify novel pathways that may lead to impaired joint homeostasis. First, a direct consequence of traumatic injury, hemarthrosis, is explored as a potential contributor to the development of PTOA specifically through contributions by red blood cells. We demonstrate for the first time the differential roles of erythrocytes in their intact and lysed states through measures of oxidative stress and changes to metabolomic profiles in the context of ferroptosis. Furthermore, we demonstrate the therapeutic potential of Ferrostatin-1, a lipophilic radical scavenger in inhibiting pathological changes to cartilage and its crosstalk with the neighboring synovium in an in vitro model of hemophilic arthropathy. Second, a strategy to prevent an indirect consequence of traumatic injury, arthrofibrosis, is presented in an in vitro model of joint contraction. Fibrosis and the presence of hyperplastic synovium are implicated in the progression of OA through pathological shifts in tissue composition as well as secreted factors that promote cartilage degeneration and the maintenance of a pro-inflammatory joint environment. A type I transforming growth factor beta-1 receptor inhibitor, SB-431542, is encapsulated in polymeric microspheres for the prophylactic treatment of arthrofibrosis through sustained low-dose drug delivery to circumvent the challenges associated with resident joint clearance rates. Utilizing human-based in vitro models of cartilage and synovium pathology, we present novel mechanisms and therapeutic strategies to prevent pathological changes following traumatic joint injury that may contribute to the development of PTOA. In Part II, the sustained delivery platform introduced in Part I is extended to the treatment of PTOA. Osteochondral graft transplantation is currently the clinical gold standard for large focal cartilage lesions. However, allograft procedures are limited due to the lack of available donor tissues and autografts are associated with complications due to donor-site morbidity. In both cases, grafts are subject to failure, potentially in part due to the continual presence of pro-inflammatory factors following surgical procedure. In this section, we present cellular agarose hydrogels embedded with dexamethasone-releasing microspheres that are integrated with a titanium base as a functional tissue-engineered alternative to native osteochondral allografts. These allogenic tissue-engineered grafts were assessed in an in vivo preclinical canine model in their ability to maintain clinical function and to modulate the inflammatory response over the course of 12 months. We successfully demonstrated the feasibility of using engineered grafts by comparing clinical measures of range of motion, function, lameness, and pain, as well as modified cartilage graft scores, against native osteochondral allograft controls. In addition, improvements in the histopathological scoring of neighboring synovial and meniscal tissues indicate the therapeutic capacity of dexamethasone released from within the joint to modulate the inflammatory response up to one-year post-implantation. Taken together, the studies presented in this dissertation identify novel mechanisms behind pathological changes to the cartilage and synovium that may contribute to the development of PTOA following injury. Potential therapeutic targets, inhibitory compounds, and delivery strategies are also assessed using human-based in vitro models of disease and further validated in an in vivo canine model through a clinically relevant timeframe. Ultimately, we demonstrate for the first time, the use of dual-function tissue-engineered grafts in a weight-bearing region of the knee joint to circumvent limitations associated with the clinical gold standard for the treatment of large focal cartilage defects.