El objetivo principal de esta tesis doctoral es el diseño de un andamio polimérico bicapa macroporoso para la regeneración del complejo osteocondral. El material empleado para la fabricación del constructo ha sido el ácido poli(L-láctico), un polímero biodegradable de la familia de los poliésteres. Una de las capas del andamio ha sido diseñada para asistir la regeneración del cartílago articular. La otra capa sirve de anclaje al hueso subcondral, y se diferencia de la anterior en sus propiedades mecánicas y bioactividad. Este comportamiento ha sido logrado por combinación del ácido poli(L-láctico) con nanopartículas inorgánicas. Ambas capas están unidas entre sí por una fina capa de material no poroso que evita el flujo de células de una parte a otra del constructo. Para lograr este objetivo se realizó un primer estudio de diseño variando la morfología de los andamios hasta obtener aquella arquitectura más adecuada para la regeneración de ambos tejidos. Se varió parámetros de síntesis tales como la concentración de polímero y el ratio entre polímero y porógeno. Los andamios fueron evaluados mecánica y fisicoquímicamente y se seleccionó los parámetros de síntesis del ácido poli(L-láctico) que dieron mejores resultados. En la regeneración del tejido es esencial conocer cómo variarán las propiedades del material una vez sea implantado y comience su degradación. Por lo tanto, fue considerado oportuno realizar un estudio de degradación del material in vitro en diversas condiciones. El estudio de la degradación fue realizado en condiciones estáticas durante 6, 12, 18, 24 semanas y 1 año y en condiciones dinámicas durante 1, 2, 4 y 6 semanas. Se evaluó tanto las características mecánicas como las fisicoquímicas tras los diversos tiempos de la degradación. Posteriormente, y para aumentar las características mecánicas y la bioactividad del anclaje óseo, se incorporó distintas cantidades de nanopartículas inorgánicas de hidroxiapatita y sílice a los andamios. / Deplaine ., H. (2012). Scaffold design and characterisation for osteochondral tissue regeneration [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14638

Cartilage repair and/or replacement is necessary for many orthopaedic conditions including fissures from blunt trauma, autograft or allograft transplantation, and replacement of focal defects with biological or synthetic constructs. In cartilage repair, initial integration between the host tissue and repair site is desirable to allow for nutrient transport, molecular deposition to enhance fixation, and eventual stress transmission across the interface. It has been postulated that effective transport and crosslinking of newly synthesized collagen molecules across a repair site may be vital to the process of integrative repair, and recent experiments have correlated collagen deposition with the strength of such repair. Other investigations have shown that enzymatic degradation of the cartilage surface may enhance integrative repair and can increase bond strength of an adhesive to cartilage. This study explored a novel approach involving photochemical bonding of cartilage tissue samples through collagen crosslinking as a means to achieve rapid and effective initial fixation, with the goal of enhancing biological integration. Photosensitized collagen gels were first analyzed via FTIR to determine the crosslinking effects with respect to collagen type and photochemical mechanism. Using the photogellation FTIR results as a parametric guide, in vitro mechanical testing of photochemically bonded meniscal fibrocartilage and hyaline articular cartilage tissues was performed using a modified single-lap shear test. Finally, the cellular viability and bond stability of a photochemically bonded cartilage interface was evaluated over seven days of in vitro culture, where the bond strength was assessed by pushout of cores from annular defects. Results of this study have demonstrated the potential of combining enzymatic surface modification with photodynamic techniques to directly bond cartilage tissues for initial fixation.

Articular cartilage provides a low-friction surface during normal joint motion and distributes forces to the underlying bone. The extracellular matrix (ECM) composition of healthy cartilage has previously been shown to be an excellent predictor of its mechanical properties. Changes in ECM composition and loss of mechanical function are known to occur with degenerative conditions such as osteoarthritis. Identifying differences in the composition-function relationships of cartilage under different anabolic, catabolic, and homeostatic conditions may thus be a useful approach for identifying factors (e.g. ECM content, distribution, and structure) which are critical to mechanical function. In addition, diagnostic tools capable of monitoring changes in the cartilage ECM may increase our understanding of the effects of ECM changes on composition-functions relationships. The goals of this work were to investigate composition-function relationships in healthy, degraded, and engineered cartilage and to develop a microcomputed tomography-based approach to analyze changes in matrix composition and morphology in articular cartilage. In healthy explants, compressive and shear properties were dependent on both sGAG and collagen content. In contrast, the compressive properties of IL-1stimulated cartilage were dependent on sGAG but not collagen content. To assess changes in sGAG content, EPIC-microcomputed tomography, a 3D contrast-enhanced microcomputed tomography technique was developed. EPIC-microcomputed tomography attenuation was found to be an excellent predictor of sGAG content in IL-1-stimulated cartilage explants and engineered cartilage. In addition, analytical approaches were developed to use EPIC-microcomputed tomography for the in situ analysis of cartilage morphology. EPIC-microcomputed tomography was also used to analyze spatial differences in sGAG accumulation in bilayer engineered cartilage for comparison with the local strain profile. This work underscores the significance of ECM composition and structure in regulating cartilage mechanical properties and validates the use of EPIC-microcomputed tomography as a diagnostic for monitoring sGAG content and potentially for assessing mechanical function in models of degeneration and regeneration.

Thesis (Ph.D.)--University of Alberta, 2010. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Experimental Surgery, Department of Surgery. Title from pdf file main screen (viewed on April 24, 2010). Includes bibliographical references.

[Truncated abstract] Articular cartilage (AC) covers the surface of synovial joints providing a nearly frictionless bearing surface and distributing mechanical load. Joint trauma can damage the articular surface causing pain, loss of mobility and deformation. Currently there is no uniform treatment protocol for managing focal cartilage defects, with most treatment options targeted towards symptomatic relief but not limiting the progression into osteoarthritis (OA). Autologous chondrocyte implantation (ACI) and more recently matrix-induced autologous chondrocyte implantation (MACI), have emerged as promising methods for producing hyaline or hyaline-like repair tissue, however there remains some controversy regarding the exact histological nature of the tissue formed. Histological characterisation of AC repairs requires destructive tissue biopsy potentially inducing further joint pathology thereby negating the treatment effect. OA is recognised as a major cause of pain, loss of function and disability in Western populations, however the exact aetiology is yet to be elucidated. The assessment of both OA and cartilage repair has been limited to macroscopic observation, radiography, magnetic resonance imaging (MRI) or destructive biopsy. The development of non-destructive AC assessment modalities will facilitate further development of AC repair techniques and enable early monitoring of OA changes in both experimental animal models and clinical subjects. Confocal laser scanning microscopy (CLSM) is a type of fluorescence microscopy that generates high-resolution three-dimensional images from relatively thick sections of tissue. ... Biomechanical analysis suggested that the mechanical properties of MACI tissue remain inferior for at least three months. This study showed the potential of a multi-site sheep model of articular cartilage defect repair and validated its assessment via LSCA. Finally, the LSCA was used to arthroscopically image the cartilage of an intact fresh frozen cadaveric knee from a patient with clinically diagnosed OA. Images were correlated to ICRS (Outerbridge) Grades I-IV and histology. The LSCA gave excellent visualization of cell morphology and cell density to a depth of up to 200'm. Classical OA changes including clustering chondrocytes, surface fibrillation and fissure formation were imaged. Fair to moderate agreement was demonstrated with statistically significant correlations between all modalities. This study confirmed the viability of the LSCA for non-destructive imaging of the microstructure of the OA cartilage. In conclusion, the LSCA identified histological features of orthopaedic tissues, accurately quantified chondrocyte morphology and demonstrated classical OA changes. While the development and investigation of an ovine model of cartilage repair showed the treatment benefit of MACI, some biomechanical issues remain. Ultimately, the LSCA has been demonstrated as a reliable nondestructive imaging modality capable of providing optical histology without the need for mechanical biopsy. Medical Subject Headings (MESH): articular cartilage; autologous chondrocyte implantation; matrix-induced autologous chondrocyte implantation; biomechanics; cartilage; confocal microscopy; diagnosis; histology; image analysis; immunohistochemistry; magnetic resonance imaging; microscopy; osteoarthritis

The effect of synovial membrane products and mechanical pressure upon the metabolism of articular cartilage proteoglycans has been studied in vitro. The degradation of cartilage proteoglycans was studied in an organ culture system and measured as the release of [35S ] sulphate from prelabelled cartilage. The effect of synovial membrane products upon the synthesis of proteoglycans was studied in a chondrocyte monolayer system and the effect of mechanical pressure upon the synthesis of proteoglycans in an organ culture system. In both types of experiments [35S] sulphate was used as precursor. The findings may be summarized as follows 1 Conditioned synovial medium (control-SM) enhanced the degradation and reduced the synthesis of cartilage proteoglycans. In addition the degradation was further enhanced when the synovial tissue had been cultured in the presence of dextran sulphate. 2 Conditioned medium from synovial tissue cultured in the presence of indo-methacin (indo-SM), significantly reduced the synthesis of cartilage proteoglycans in chondrocyte cultures and reduced, although non-significantly, the degradation of proteoglycans in whole cartilage cultures. 3 Addition o f the prostaglandins E1 or E2 (PGE1 or PGE2 ) together with indo-SM to the cartilage cultures greatly enhanced cartilage degradation whereas the addition of PGE1 or PGE2 together with control-SM had no effect compared with that of control-SM alone. 4 Conditioned medium from synovial tissue cultured in the presence of low doses of glucocorticoids reduced cartilage degradation compared with control-SM. However, addition of control-SM together w ith low concentrations of glucocorticoids to the cartilage cultures significantly enhanced cartilage degradation. 5 Conditioned medium from synovial tissue cultured with actinomycin D or cycloheximide did not enhance cartilage degradation compared with cartilage cultured alone. 6 A continuous pressure of approximately 30 kgfcm-2 on cultures of cartilage reduced both the synthesis and the degradation o f cartilage proteoglycans. Although it is difficult to extrapolate from the in vitro to the in vivo situation, it is proposed that some factor(s) from the synovial membrane have the capacity to enhance the degradation and reduce the synthesis o f articular cartilage proteoglycans. From these experiments it cannot be completely excluded that treatm ent of arthritic joints with non-steroidal or streroidal anti-inflammatory drugs may result under certain conditions in enhanced joint damage. It is also suggested that under certain conditions the metabolism o f cartilage proteoglycans could be directly affected by mechanical stress. / <p>Diss. Umeå, Umeå universitet, 1982, härtill 6 uppsatser</p> / digitalisering@umu

Bone bruise lesions (BBL) are documented on MRIs diagnosing acute knee ligament injury (AKLI). Recent evidence has indicated that a majority of patients that sustain an AKLI, especially anterior cruciate ligament (ACL) knee injury, will develop post-traumatic osteoarthritis (PTOA) 10-20 years following injury. It has been proposed that the initial damage sustained to the articular cartilage overlying BBL causes a cascade of events that may result in PTOA. Researchers have proposed a modification to treatment protocols for more severe BBL, or have stressed the need for the development of protective therapies to protect the articular cartilage. However, there are limited tools available to evaluate the clinical outcome of articular cartilage overlying BBL. Furthermore, damage to the cartilage overlying BBL may be different according to differing BBL severities. Therefore, the use of a cartilage degradation biomarker, serum cartilage oligomeric matrix protein (sCOMP) and the use of a BBL severity classification system may be useful to determine if differences exist between patients with and without BBL, and with differing BBL severities. The purpose of this dissertation was to investigate the utility of sCOMP as a biomarker for acute articular cartilage damage. The purposes of these studies were to determine the inter and intraday reliability of this marker, to document sCOMP longitudinally in collegiate athletes and following AKLI, and to determine if differences in sCOMP and self-reported pain and function exist for patients with and without BBL, and differing BBL following AKLI. The results of these studies indicated sCOMP measures had strong inter and intraday reliability. Additionally, exercise does seem to influence sCOMP levels; however, these elevations may not be clinically meaningful. Furthermore, sCOMP levels were not different between patients with BBL and without, and between differing BBL severities. The results of these studies support the use of a BBL severity classification for future research studies in order to further elucidate the outcomes of these lesions.

Traumatic defects in articular cartilage can lead to joint disease and disability including osteoarthritis. Because cartilage is unable to regenerate when injured, the field of tissue engineering holds promise in restoring functional tissue. In this research, type II collagen was electrospun, cross-linked, and tested as scaffolds for supporting chondrocyte growth. The mechanical, biochemical, and histological characteristics of the engineered tissue were assessed as a function of the electrospinning solution concentration (i.e. scaffold fiber diameter and pore properties) and as a function of the time in culture (evaluated at 2, 4, and 6 weeks). Fiber diameter had a linear relationship with concentration: mean diameter increased from 107 to 446 nm and from 289 to 618 nm, measured with SEM and permeability meter, respectively, with increasing concentration, from 60 mg/mL to 120 mg/mL. Pore size revealed no relationship with concentration but mean values ranged in size from 1.76 to 3.17 μ2 or from 0.00055 to 0.0028 μ2, depending on the measurement technique. Average porosity ranged from 84.1 to 89.1%, and average permeability was between 6.82x10-4 and 35.0 x10-4 D. Histological analysis revealed a relatively high number of spherical cells, possibly indicating the expression of the chondrocyte phenotype. However, there were very little glycosaminoglycans and type II collagen synthesized by the cells despite an increase in the cell density over time for the 60, 80, and 100 mg/mL concentrations. The mean values for peak stress (between 0.17 and 0.35 MPa) and tangential modulus (between 0.32 and 0.64 MPa) for the mats are at least an order of magnitude less than that for native cartilage, while the mean values for strain at break (between 93 and 150%) for the mats are at least an order of magnitude greater than that for native cartilage. The equilibrium stiffness for all concentrations decreased from week 2 to week 6 of tissue culture (which may correlate with increasing cell density); the 100 mg/mL concentration had the highest mean value (0.084 MPa at week 2) and the lowest mean value (0.010 MPa at week 6). This research did not indicate any significant findings regarding the influence of concentration or culture time on chondrogenesis. Because the cells appeared to grow on the surface of the scaffold but there was a lack of cell migration into the scaffold, the scaffold material may be sufficient to support chondrocyte growth but the scaffold physical design must be reconsidered.

Diferenças na espessura e regularidade da cartilagem da articulação temporomandibular (ATM) ocorrem como o resultado de áreas em crescimento ou em remodelamento. Esse aspecto dificulta a interpretação clínica das imagens e geralmente negligencia a presença da fibrocartilagem. O estudo, por meio da Ressonância Magnética utilizando bobinas microscópicas, possibilita uma melhor observação da cartilagem articular. Confirmamos essa evidência por meio do estudo que analisou 20 indivíduos (40 ATM), divididos em grupo sintomático (DTM) com 10 pacientes (20 ATM) apresentando queixa clínica e suspeita diagnóstica de DTM e, o grupo controle com 10 voluntários (20 ATM) assintomáticos ou que não apresentavam sinais e sintomas clínicos de DTM. As imagens de RM sagitais oblíquas ponderadas em DP SPIR da ATM foram capazes de mostrar a cartilagem com melhor evidência tanto na cabeça da mandíbula quanto na eminência articular proporcionado mensurações, as quais se apresentaram estatisticamente iguais entre os grupos e também a avaliação da regularidade com o mesmo comportamento entre os grupos e geralmente acompanhando a morfologia da cortical óssea. Em muitos casos, principalmente quando da presença de deslocamento para anterior do disco articular, a observação se torna mais difícil, requerendo mais prática para esse tipo de avaliação. Observamos que pacientes do grupo controle apresentaram deslocamento de disco. Dessa maneira, consideramos um exame muito útil como auxiliar no diagnóstico da DTM, e com o desenvolvimento de novas terapias para doenças degenerativas e traumas na cartilagem, as imagens de RM com o uso de bobina microscópica são de crescente importância clínica e poderão desempenhar um papel importante na avaliação da eficácia dessas terapias. / Differences in thickness and regularity of the temporomandibular joints (TMJ) cartilage occur as the result of areas of growth or remodeling. This fact leads to misinterpretations on diagnosis and generally neglects the presence of fibrocartilage. The present study, using MRI microscopic coils, allows better observation of the articular cartilage. This evidence was confirmed by this study that examined 20 individuals (40 TMJ), divided into: symptomatic group with temporomandibular dysfunction (TMD) of 10 patients (20 TMJ) presenting clinical complaint and TMD diagnosis; and the control group of 10 volunteers (20 TMJ) that were asymptomatic or who had no clinical signs and symptoms of TMD. On both groups were measured cartilage thickness and if the cartilage was regular or not. The oblique sagital MR images of weighted SPIR protons density (PD\'s) TMJ were able to show the best cartilage images either in the mandibles head or on the articular eminence providing measurements. Both groups presented no statistically significant differences regarding to thickness and the evaluation of the regularity presented the same result. The regularity of the cartilage generally was similar to the morphology of the cortical bone. In many cases, especially when the presence of anterior articular disc displacement, the evaluation was more difficult, requiring practice. The control group with asymptomatic patients was found also to have disc displacements. Thus, we review a very useful tool in the diagnosis of TMD and its importance to evaluate the cartilage to development new therapies for degenerative diseases and trauma. The MRI images with the use of microscopic coil are of increasing clinical importance and might play an important role in assessing the effectiveness of these therapies.

A subnutrição tem sido ao longo dos anos um dos maiores problemas de saúde pública do mundo, que acomete principalmente crianças de países em desenvolvimento. Estima-se que em Moçambique na África Oriental, cerca de 40% das crianças são acometidas pela desnutrição crônica que resulta dentre outras afecções em baixa estatura e diminuição da capacidade física. Este estudo visa avaliar a estrutura óssea de ratos wistar submetidos à dieta básica da população de Moçambique (DM) reproduzida em laboratório. Para isso a DM foi oferecida aos animais em fase pré e pós-natal durante 42 dias. Para alguns desses animais foi fornecida a DM acrescida de 20% de caseína (DMC) subsequentemente os grupos subnutrido de Moçambique (SM) e nutrido de Moçambique (NM). Foi formado também um grupo denominado renutrido (RM) composto por animais que receberão a DMC a partir do 22&ordm; dia e até completarem 42 dias de vida. Após o desmame foram mensurados os parâmetros metabólicos da ingestão alimentar e hídrica, excreção de urina e fezes. A tíbia e o úmero do lado direito foram macerados quimicamente a fim de verificar as medidas ósseas. Esses ossos do lado esquerdo foram processados com técnicas rotineiras histológicas e corados de forma a evidenciar as estruturas cartilagineas. Os dados obtidos foram submetidos a análise de variância paramétrica seguida por comparações múltiplas pelo método de Tukey, com nível de significância p&lt;0,05. Os resultados apontam que a Subnutrição é capaz de modificar a espessura da CA e da LE e os componentes de sua MEC. Embora a inserção de caseína na dieta dos animais SM, tenha reestabelecido parâmetros da osteometria, na LE e na CA a melhora apresentada, não foi o suficiente para atingir seus parâmetros normais apresentados no grupo NM / Undernutrition has been over the years one of the major public health problems worldwide, which affects mainly children in developing countries. It is estimated that in Mozambique in East Africa, about 40% of children are affected by chronic undernutrition resulting from other conditions in stature and diminished physical capacity. This study aims to evaluate the bone structure of Wistar rats submitted to the staple diet of the population of Mozambique (DM) reproduced in the laboratory. To this DM was given to the animals in pre and postnatal 42 days. For some of these animals was provided to DM plus 20% casein (DMC) subsequently the undernourished groups of Mozambique (SM) and nursed Mozambique (NM). Also it has formed a group called renutrido (RM) consists of animals that receive the DMC from the 22nd day until completing 42 days of life. After weaning metabolic parameters were measured food and water intake, urine output and feces. The tibia and the humerus on the right side were chemically macerated in order to verify the bone measurements. These bones on the left side were processed with routine histological techniques, and stained to show the form cartilage structures. The data were subjected to parametric analysis of variance followed by multiple comparisons by the Tukey method, with significance level of p <0.05. The results show that the Malnutrition is able to modify the thickness of the CA and LE and the components of its MEC. Although the inclusion of casein in the diet of animals SM, has reestablished osteometria parameters in LE and CA improvement presented, was not enough to achieve their normal parameters presented in NM group