Effet des contraintes mécaniques sur le développement de l'arthrite

Rheumatoid arthritis (RA) is the most common chronic inflammatory rheumatic disease. A number of aspects need to be taken in account to improve the management of patients with RA, such as lifestyle, drug treatments and associated diseases. The different objectives of this thesis are on the one hand to investigate the effect of mechanical loading and unloading on the RA development. On the other hand, it is to investigate the co-administration of folic acid (FA) with MTX compared to a delayed administration used in clinic. The pulmonary involvement in the adjuvant-induced arthritis (AIA) model was also investigated. The AIA model mimics the pathophysiology of RA, and improving pain management in rodents was necessary to ensure its continued use. The study of mechanical stresses on RA showed that mechanical unloading prevents the development of arthritis by inhibiting YAP and CCL2-mediated inflammation. Increased mechanical stress in pre-clinical arthritis tends to increase inflammation and bone loss in early arthritis. The pre-clinical study on MTX showed that the co-administration of FA with MTX does not impact MTX efficacy. The goal is to develop a new therapeutic combining MTX and FA, in order to improve patient compliance. Finally, the AIA model develops a non-specific interstitial lung disease, allowing the study of mechanisms involved in this extra-articular manifestation of RA.La polyarthrite rhumatoïde (PR) est la maladie ostéo-articulaire chronique inflammatoire la plus fréquente. Plusieurs aspects sont à prendre en compte pour améliorer la prise en charge des patients atteints de PR, tels le mode de vie, les traitements médicamenteux et les maladies associées. Les différents objectifs visaient d’une part à étudier l’effet des contraintes mécaniques dans le développement de la PR, et d’autre part à étudier la co-administration de l’acide folique (AF) au MTX par rapport à une administration différée utilisée en pratique courante. Une recherche d’atteinte pulmonaire dans le modèle d’arthrite induite par adjuvant (AIA) a également été réalisée. Le modèle d’AIA mime la physiopathologie de la PR, et l’amélioration de la prise en charge de la douleur de ce modèle était nécessaire pour assurer la continuité de son utilisation. L’étude des contraintes mécaniques sur la PR a permis de montrer qu’une décharge mécanique prévient le développement de l’arthrite en inhibant l’inflammation médiée par YAP et CCL2. L’augmentation du stress mécanique en phase pré-clinique de l’arthrite tend à augmenter l’inflammation et la perte osseuse en phase précoce de l’arthrite. L’étude pré-clinique sur le MTX a montré que la co-adminstration d’AF au MTX n’impacte pas l’efficacité du traitement. Ces résultats incitent à tester une nouvelle formulation thérapeutique combinant MTX et AF, dans le but d’améliorer la prise en charge des patients. Pour finir, le modèle AIA développe une pneumopathie interstitielle non spécifique, permettant l’étude de mécanismes impliqués dans cette manifestation extra-articulaire de la PR

Effet des contraintes mécaniques sur le développement de l'arthrite

Rheumatoid arthritis (RA) is the most common chronic inflammatory rheumatic disease. A number of aspects need to be taken in account to improve the management of patients with RA, such as lifestyle, drug treatments and associated diseases. The different objectives of this thesis are on the one hand to investigate the effect of mechanical loading and unloading on the RA development. On the other hand, it is to investigate the co-administration of folic acid (FA) with MTX compared to a delayed administration used in clinic. The pulmonary involvement in the adjuvant-induced arthritis (AIA) model was also investigated. The AIA model mimics the pathophysiology of RA, and improving pain management in rodents was necessary to ensure its continued use. The study of mechanical stresses on RA showed that mechanical unloading prevents the development of arthritis by inhibiting YAP and CCL2-mediated inflammation. Increased mechanical stress in pre-clinical arthritis tends to increase inflammation and bone loss in early arthritis. The pre-clinical study on MTX showed that the co-administration of FA with MTX does not impact MTX efficacy. The goal is to develop a new therapeutic combining MTX and FA, in order to improve patient compliance. Finally, the AIA model develops a non-specific interstitial lung disease, allowing the study of mechanisms involved in this extra-articular manifestation of RA.La polyarthrite rhumatoïde (PR) est la maladie ostéo-articulaire chronique inflammatoire la plus fréquente. Plusieurs aspects sont à prendre en compte pour améliorer la prise en charge des patients atteints de PR, tels le mode de vie, les traitements médicamenteux et les maladies associées. Les différents objectifs visaient d’une part à étudier l’effet des contraintes mécaniques dans le développement de la PR, et d’autre part à étudier la co-administration de l’acide folique (AF) au MTX par rapport à une administration différée utilisée en pratique courante. Une recherche d’atteinte pulmonaire dans le modèle d’arthrite induite par adjuvant (AIA) a également été réalisée. Le modèle d’AIA mime la physiopathologie de la PR, et l’amélioration de la prise en charge de la douleur de ce modèle était nécessaire pour assurer la continuité de son utilisation. L’étude des contraintes mécaniques sur la PR a permis de montrer qu’une décharge mécanique prévient le développement de l’arthrite en inhibant l’inflammation médiée par YAP et CCL2. L’augmentation du stress mécanique en phase pré-clinique de l’arthrite tend à augmenter l’inflammation et la perte osseuse en phase précoce de l’arthrite. L’étude pré-clinique sur le MTX a montré que la co-adminstration d’AF au MTX n’impacte pas l’efficacité du traitement. Ces résultats incitent à tester une nouvelle formulation thérapeutique combinant MTX et AF, dans le but d’améliorer la prise en charge des patients. Pour finir, le modèle AIA développe une pneumopathie interstitielle non spécifique, permettant l’étude de mécanismes impliqués dans cette manifestation extra-articulaire de la PR

Similar effect of co-administration of methotrexate and folic acid for the treatment of arthritis compared to separate administration

International audienceAbstract Objectives MTX is the recommended first-line treatment for RA associated with folic acid (FA) to reduce side effects related to MTX. Here, we proposed to test a co-administration of MTX with FA in the rat adjuvant-induced arthritis (AIA) on efficacy. Material and methods AIA was induced in female Lewis rats and treated with MTX in three groups. The first group of rats received only MTX (n = 13), whereas the second received MTX and FA on the same day (n = 14). The third group received FA one day after MTX (n = 14). Arthritic index (AI), ankle circumference (AC), ankle microcomputed tomography, and blood tests assessed arthritis severity and MTX tolerance. Results AI and AC were similar in MTX groups at various time points. Bone erosion and bone loss parameters were similar in all groups. MTX-PG1 was found at similar levels in various MTX groups and correlated negatively with arthritis severity. Finally, haematology and metabolic parameters were found at a similar level in MTX groups. Conclusion Co-administration of MTX with FA on the same day did not reduce efficacy compared with FA application one day after MTX. Thus, co-administration of MTX and FA could be more convenient and improve compliance in patients

Femtosecond laser upscaling strategy and biological validation for dental screws with improved osteogenic performance

Osseointegration is one of the key conditions for long term successful dental implantation. To this end, titanium alloys undergo plethora of surface treatments able to sustain osteogenic differentiation. For these surface treatments, femtosecond laser (FSL) can generate precise and reproducible surface patterns on titanium, avoiding thermal damage and chemical pollution. We recently identify that laser-induced periodic surface structure (LIPSS) with radial orientation, generated on model (flat) titanium surface, has a high osteogenic potential. However, nano-texturing is time consuming. In the present study, we aimed to reduce the texturing time of radial LIPSS, as well as processing of large commercially available dental screws by ways of laser beam engineering. Our objectives were to maintain at least osteogenic properties demonstrated on model surfaces by adjusting laser beam diameters and to demonstrate maintenance of performance with a dental screw texturing process not exceeding 1 minute.We first textured model surfaces with radial LIPSS by laser beams of different diameters, with surface impacts of 24µm, 80µm or 180µm, named as R24, R80 or R180 respectively. Osteogenic performance of human mesenchymal stem cells (hMSCs) were compared; seeded on polished control surfaces and textured surfaces and subjected to osteogenic evaluation by cell/matrix imaging, qRT-PCR and mineral deposition quantification. All textured surfaces showed greater osteogenic potential than the control surfaces, with significantly higher efficacy on R180 surface. Therefore, R180 pattern with large beam impacts was chosen for texturing on a dental screw and its osteogenic activity was compared to that of a non-textured screw. Interestingly, R180 required only 40 seconds to be textured on whole screws, on which it preserved a high osteogenic potential. Thus, by using FSL technology, we have improved the osteogenic potential of a topographic pattern while optimizing and scaling up its processing time on a medical device

Polarization of Femtosecond Laser for Titanium Alloy Nanopatterning Influences Osteoblastic Differentiation

International audienceUltrashort pulse lasers have significant advantages over conventional continuous wave and long pulse lasers for the texturing of metallic surfaces, especially for nanoscale surface structure patterning. Furthermore, ultrafast laser beam polarization allows for the precise control of the spatial alignment of nanotextures imprinted on titanium-based implant surfaces. In this article, we report the biological effect of beam polarization on human mesenchymal stem cell differentiation. We created, on polished titanium-6aluminum-4vanadium (Ti-6Al-4V) plates, a laser-induced periodic surface structure (LIPSS) using linear or azimuthal polarization of infrared beams to generate linear or radial LIPSS, respectively. The main difference between the two surfaces was the microstructural anisotropy of the linear LIPSS and the isotropy of the radial LIPSS. At 7 d post seeding, cells on the radial LIPSS surface showed the highest extracellular fibronectin production. At 14 days, qRT-PCR showed on the same surface an increase in osteogenesis-related genes, such as alkaline phosphatase and osterix. At 21 d, mineralization clusters indicative of final osteoinduction were more abundant on the radial LIPSS. Taken together, we identified that creating more isotropic than linear surfaces enhances cell differentiation, resulting in an improved osseointegration. Thus, the fine tuning of ultrashort pulse lasers may be a promising new route for the functionalization of medical implants

Femtosecond laser upscaling strategy and biological validation for dental screws with improved osteogenic performance

Osseointegration is one of the key conditions for long term successful dental implantation. To this end, titanium alloys undergo plethora of surface treatments able to sustain osteogenic differentiation. For these surface treatments, femtosecond laser (FSL) can generate precise and reproducible surface patterns on titanium, avoiding thermal damage and chemical pollution. We recently identify that laser-induced periodic surface structure (LIPSS) with radial orientation, generated on model (flat) titanium surface, has a high osteogenic potential. However, nano-texturing is time consuming. In the present study, we aimed to reduce the texturing time of radial LIPSS, as well as processing of large commercially available dental screws by ways of laser beam engineering. Our objectives were to maintain at least osteogenic properties demonstrated on model surfaces by adjusting laser beam diameters and to demonstrate maintenance of performance with a dental screw texturing process not exceeding 1 minute.We first textured model surfaces with radial LIPSS by laser beams of different diameters, with surface impacts of 24µm, 80µm or 180µm, named as R24, R80 or R180 respectively. Osteogenic performance of human mesenchymal stem cells (hMSCs) were compared; seeded on polished control surfaces and textured surfaces and subjected to osteogenic evaluation by cell/matrix imaging, qRT-PCR and mineral deposition quantification. All textured surfaces showed greater osteogenic potential than the control surfaces, with significantly higher efficacy on R180 surface. Therefore, R180 pattern with large beam impacts was chosen for texturing on a dental screw and its osteogenic activity was compared to that of a non-textured screw. Interestingly, R180 required only 40 seconds to be textured on whole screws, on which it preserved a high osteogenic potential. Thus, by using FSL technology, we have improved the osteogenic potential of a topographic pattern while optimizing and scaling up its processing time on a medical device

Comment les lasers ultra-courts aident à créer des reliefs hiérarchiques guidant efficacement les cellules sur des motifs nanostructurés

International audienceUltra-short laser texturing allows us to produce various surface reliefs on both nano- and micro-scales as complex hierarchical patterns. This kind of surface treatment has also advantaged in the reduction of thermal effects, of debris, and, particularly, in the minimization of surface contamination. Particularly, surface micro-patterns with additional nano-reliefs, or so-called “hierarchical reliefs” can be quite easily produced considerably alternating not only surface roughness and wettability but allowing additional opportunities to better guide the behavior of different objects ranging from nanoparticles and viruses to larger droplets and/or living microorganisms. Previously, a clear connection between cell behavior and wetting properties on laser-structured patterns has been revealed. However, the optimum laser treatment is still under discussion. In fact, laser interactions affect not only surface relief and morphology but also composition, phase state, etc. One of the known challenges is also the fact that surface properties can be unstable and evolve with time. They can be also strongly affected by additional heating, sterilization, ultra-sound or cold plasma treatment. The reasons for these changes are not yet well understood. For this, femtosecond laser irradiation of titanium-based surfaces is used. As a result, multi-scale textures are produced with high precision. Additionally, computer simulations were also performed to examine surface chemistry and particle and small droplet behavior on such surfaces. Then, wetting properties are analyzed. Finally, the capacities to capture and guide human stem cell cultures (HSC) were evaluated. Several patterns with different sizes and motifs have been examined. In general, the results confirm that wettability maps can help predict cellular behavior. The obtained results have numerous applications in bioengineering, cellular tests, the treatment of dental implants, and various prosthesis.La texturation laser ultra-courte nous permet de produire divers reliefs de surface à la fois à l'échelle nano et micro sous forme de motifs hiérarchiques complexes. Ce type de traitement de surface présente également des avantages dans la réduction des effets thermiques, des débris et, en particulier, dans la minimisation de la contamination de surface. En particulier, des micro-motifs de surface avec des nano-reliefs supplémentaires, ou soi-disant «reliefs hiérarchiques», peuvent être assez facilement produits en alternant considérablement non seulement la rugosité de surface et la mouillabilité, mais permettant des opportunités supplémentaires pour mieux guider le comportement de différents objets allant des nanoparticules aux virus. à des gouttelettes plus grosses et/ou à des micro-organismes vivants. Auparavant, un lien clair entre le comportement des cellules et les propriétés de mouillage sur les motifs structurés au laser a été révélé. Cependant, le traitement au laser optimal est encore en discussion. En fait, les interactions laser affectent non seulement le relief et la morphologie de la surface, mais aussi sa composition, son état de phase, etc. L'un des défis connus est également le fait que les propriétés de surface peuvent être instables et évoluer avec le temps. Ils peuvent également être fortement affectés par un chauffage supplémentaire, une stérilisation, un traitement aux ultrasons ou au plasma froid. Les raisons de ces changements ne sont pas encore bien comprises. Pour cela, une irradiation laser femtoseconde de surfaces à base de titane est utilisée. En conséquence, des textures multi-échelles sont produites avec une grande précision. De plus, des simulations informatiques ont également été effectuées pour examiner la chimie de surface et le comportement des particules et des petites gouttelettes sur ces surfaces. Ensuite, les propriétés de mouillage sont analysées. Enfin, les capacités de capture et de guidage des cultures de cellules souches humaines (CSH) ont été évaluées. Plusieurs modèles avec des tailles et des motifs différents ont été examinés. En général, les résultats confirment que les cartes de mouillabilité peuvent aider à prédire le comportement cellulaire. Les résultats obtenus ont de nombreuses applications dans la bio-ingénierie, les tests cellulaires, le traitement des implants dentaires et diverses prothèses