WorldCat Identities

Wittrant, Yohann (1978-....).

Overview
Works: 13 works in 15 publications in 2 languages and 20 library holdings
Roles: Opponent, Author, Other, Thesis advisor
Classifications: QH519, 616.994
Publication Timeline
.
Most widely held works by Yohann Wittrant
Nouvelles approches thérapeutiques des ostéosarcomes. by Yohann Wittrant( Book )

2 editions published in 2005 in French and held by 3 WorldCat member libraries worldwide

L'ostéosarcome est la plus fréquente des tumeurs osseuses primitives non hématologiques affectant une population relativement jeune, dont les thérapies conventionnelles montrent désormais leurs limites, et nécessite par conséquent de développer de nouveaux traitements. Récemment découverte, la triade moléculaire Receptor Activator of NFkB / RANK Ligand / Ostéoprotégérine (RANK / RANKL / OPG) représente un pivot dans la régulation de la balance apposition/ résorption osseuse. Cet équilibre est affecté lors développement de l'ostéosarcome. L'objectif de cette thèse a été de développer de nouvelles approches thérapeutiques dans des modèles expérimentaux d'ostéosarcomes basées sur une meilleure connaissance de la biologie osseuse, notamment le rôle physiologique et le potentiel thérapeutique de triade. Par ailleurs, en raison de l'interaction des systèmes osseux et immunitaire, l'élaboration de protocoles d'immunothérapie active par l'utilisation de cellules dendritiques a été entreprise
Utilisation des procyanidines et de l'hydroxytyrosol dans la prévention nutritionnelle de l'arthrose by Elsa Mével( )

2 editions published in 2015 in French and held by 2 WorldCat member libraries worldwide

Osteoarthritis (OA) is a major health concern that affects a growing part of the aging population. Nowadays, among differents existing therapeutic strategies, none of them is able to treat the origin of the disease. The mechanisms leading to inflammation and cartilage breakdown are well understood and allow defining an etiologic and not only symptomatic patient care. The nutraceutical use in prevention of OA seems to be an interesting strategy. In this way, our study was focused on the development of preventive strategy of OA by using hydroxytyrosol and/or procyanidines which were extracted from olive and grape for a translational approach. We showed that these molecules had a protective effect on the production of inflammatory and catabolic markers on l'IL-1ß treatment on freshly isolated cells and in cartilage explants. Our work has also demonstrated that the extracts are bioavailable after oral administration and conserved their chondroprotective effect in rabbit and dog. Finally, our study underlined a nutritional prevention with hydroxytyrosol and/or procyanidines on surgically induced osteoarthritis in mice and rabbit. Altogether, these results offered promising alternatives in the design of new strategy in nutraceutical management of OA
Non-targeted and targeted analysis of collagen hydrolysates during the course of digestion and absorption by Anne J Kleinnijenhuis( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

Increased body fat mass and tissue lipotoxicity associated with ovariectomy or high-fat diet differentially affects bone and skeletal muscle metabolism in rats by Camille Tagliaferri( )

1 edition published in 2014 in English and held by 2 WorldCat member libraries worldwide

Pomegranate and its derivatives can improve bone health through decreased inflammation and oxidative stress in an animal model of postmenopausal osteoporosis by Mélanie Spilmont( )

1 edition published in 2013 in English and held by 2 WorldCat member libraries worldwide

GPR40, a free fatty acid receptor, differentially impacts osteoblast behavior depending on differentiation stage and environment by Claire Philippe( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

Nouvelles approches thérapeutiques des ostéosarcomes by Yohann Wittrant( )

1 edition published in 2005 in French and held by 1 WorldCat member library worldwide

Osteosarcoma is the most frequent primary bone tumour that develops mainly in the young, the median age of diagnosis being 18 years. Despite recent improvements, current strategy for treatment of high-grade osteosarcoma lead to pulmonary metastasis apparition and new therapeutic approaches need to be developed. Recently discovered, the molecular triad Receptor Activator of NFkB / RANK Ligand / Ostéoprotégérine (RANK / RANKL / OPG) is a pivotal key in bone formation/degradation balance regulation. Osteosarcoma affects this regulation. The aim of this thesis was to develop new therapeutic design based upon better knowledge in bone biology, most notably physiologic role and therapeutic potential of OPG/RANK/RANKL using animal models. Moreover, due to bone and immune systems interaction, we started active immunotherapy's protocols using dendritic cells
L'ion phosphate en tant que molécule de signalisation : mécanismes moléculaires impliqués dans la différenciation des cellules minéralo-compétentes by Annabelle Bourgine( Book )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

Inorganic phosphate (Pi) is an essential component of the organism both in terms of structure and metabolism. Pi is also able to activate many signaling pathways particularly in mineralizing cells. Disorders resulting from disturbances of its homeostasis, such as rickets or ectopic calcifications, highlight the importance of Pi in the body. This work is structured around the mechanisms involved in the differentiation of chondrocytes, osteoblasts and odontoblasts in response to Pi, and the involvement of calcium (Ca) in the cellular effects induced by Pi. We have shown that Pi and Ca, especially through the formation of phosphocalcic precipitates are able, via the ERK1/2 pathway, to stimulate the expression of proteins involved in mineralization such as matrix gla protein and osteopontin, as well as apoptosis and expression of PiT1 and PiT2 transporters. These data highlight the importance of the role of Pi as a signaling molecule in the differentiation of mineralizing cells. We have also shown that PiT1 and PiT2 play a role in mineralization. However, we suggest that these proteins may be involved via a potential function of Pi sensing, which is independent of their established function of Pi transport. They also challenge the involvement of PiT1 and PiT2 through their role of Pi transport in the mineralization process, and lead to consider henceforth as multifunctional proteins
Mise au point, caractérisation et optimisation d'hybrides organominéraux à base de polycaprolactone et bioverre pour la régénération tissulaire osseuse : Ingénierie tissulaire osseuse by Henri Granel( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Les avancées technologiques dans le domaine de la médecine régénérative ont permis l'accès à un vaste panel de biomatériaux. Pourtant, la réparation de certains défauts osseux continue de poser problèmes et des améliorations sont requises. Dans ce contexte, les propriétés des verres bioactifs (BV) en font des candidats sérieux. Ils sont d'ailleurs déjà utilisés, cependant, leur grande fragilité limite leurs applications et notamment leur utilisation comme scaffolds poreux. Le développement du procédé de synthèse sol-gel a contribué à résoudre ces difficultés.Cette technique permet de combiner le BV avec un polymère pour conférer au biomatériau de la ténacité. On peut alors envisager la création de scaffolds poreux adaptés à la régénération du tissu osseux. Récemment, le Laboratoire de Physique Corpusculaire est parvenu à synthétiser ce type de biomatériaux. Ce projet de recherche multidisciplinaire a eu pour objet le développement du procédé de synthèse ainsi que la caractérisation physico-chimique et biologique des hybrides. Cette thèse présente les résultats obtenus en se focalisant sur les propriétés biologiques des biomatériaux. Après avoir sélectionné le polycaprolactone (PCL) pour la phase organique, nous avons mis en évidence la bioactivité des scaffolds ainsi qu'une vitesse de dégradation lente associée à une forte ténacité. Nous avons ensuite caractérisé leur potentiel biologique in vitro à l'aide d'un modèle d'ostéoblastes primaires de rat. Nous avons observé que ces cellules osseuses primaires étaient capables d'adhérer sur les biomatériaux (BV-PCL) et de s'y différencier. Les résultats obtenus ont montré une supériorité des hybrides par rapport à une xénogreffe commerciale de référence. Une étude animale dans un modèle murin a permis de confirmer ces résultats et de valider le potentiel des scaffolds de BV-PCL. Des dopages inorganiques (strontium) et organiques (fisétine) ont permis de doubler la régénération osseuse observée avec le BVPCLdans notre modèle animal. Les biomatériaux hybrides que nous avons développés possèdent donc un fort potentiel en régénération tissulaire osseuse. De plus, l'utilisation de composés organiques d'origine alimentaire représente une stratégie innovante et efficace pour l'amélioration des propriétés ostéoinductives de biomatériaux osseux
Effet protecteur de la vitamine D sur l'obésité et les désordres physiologiques associés by Julie Marcotorchino( )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

White adipose tissue is not a simple energy reservoir, it also secretes several molecules called adipokines. In standard conditions, adipokines are involved in general homeostasis permitting the regulation of numerous functions and metabolic pathways. During the development of obesity, adipose tissue physiology is severely disrupted. This results in dysfunction such as low-grade inflammatory status. The accumulation of these disturbances within adipose tissue generates a dysregulation of adipokines secretion. This will have for consequences a failure of some metabolic pathways resulting in insulin-resistant state leading to type 2 diabetes. Several epidemiological studies show a link between vitamin D deficiency and numerous pathologies like cancers, immunity deseases or cardiovascular deseases. In addition, there is an inverse correlation between plasma levels of 25(OH)D and the prevalence of obesity, hypertension and type 2 diabetes. However, the link between vitamin D deficiency and obesity is not well established. The aim of this thesis is to better understand the link between vitamin D deficiency, obesity and physiological disorders associated. For this purpose, we have evaluated vitamin D effects on adipose tissue and adipocyte biology (inflammation, glucose uptake) and subsequently effects of vitamin D supplementation on diet-induced obesity. In a first study in vitro, we have showed an anti-inflammatory effect of vitamin D on adipocyte. This effect appears to be VDR-dependant and implies a modulation of NFκB signaling pathway. This study could partly explain le link between vitamine D deficiency and low-grade inflammation associated with obesity
Le strontium comme inhibiteur de l'adipogenèse et modulateur du statut redox des cellules souches mésenchymateuses by Carole Fournier( )

1 edition published in 2011 in French and held by 1 WorldCat member library worldwide

Développement de synergies nutritionnelles pour l'optimisation des stratégies de prévention de l'ostéoporose by Cedric Darie( )

1 edition published in 2017 in French and held by 1 WorldCat member library worldwide

Osteoporosis is a chronic bone disease whose prevalence increases with age. It results from an alteration in the quantity and quality of the skeleton (micro-architecture and bone mineral density) with an increased risk of fracture and co-morbidities. According to recent epidemiological studies, it is estimated that this pathology affects around 30% of people over 50 years of age in Europe, resulting in an excess mortality rate of almost 30%, and in an annual socio-economic cost of nearly 30 billion euros. Current treatment is limited by non-systematic prophylaxis and the side effects of curative treatments, with compliance rates of no more than 20% within one year. To meet these challenges, new innovative preventive nutrition alternatives based on the combined use of active food ingredients are more necessary than ever. Fisetin is a polyphenol of the flavonoid class described for its anti-inflammatory activity. It is mainly found in red fruits such as strawberries. We have previously demonstrated how and to what extent fisetin inhibits osteoclast differentiation, stimulates osteoblast activity, and prevents bone loss in murine osteoporotic models. In order to optimize this beneficial effect, we have sought nutritional partners who could act in synergy with fistin. We have shown that DHA, an omega-3 polyunsaturated fatty acid, can potentiate the biological effects of fisetin at the bone level. Our work has made it possible to highlight the form of DHA and the most relevant combination ratios. Collaborative work in partnership has made it possible to develop formulations and extracts on the basis of the research results. The long-term objective is to transpose this work to patients, in order to provide marketable and scientifically supported prevention tools
Utilisation de cellules souches pulpaires combinées à une matrice de collagène pour la réparation osseuse cranio-faciale by Anne-Margaux Collignon( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

The craniofacial area is particularly vulnerable to structural loss. Its location and visibility make a loss causes disorders, both physical (food, phonation...) than psychological (integrity of the person...). Current treatments (autografts, allografts or synthetic bone grafts) are particularly invasive and have a high failure rate. All this strongly affects the quality of life of the patient. In addition, the cost of these treatments is significant for the health systems and the patient. Therefore, there is a real need to develop innovative treatments based on biomimetic tissue approaches for bone repair. The purpose of this thesis is to develop a tissue engineering approach for the repair/regeneration of injured cranial-facial bone tissue. It is based on the use of cellularized scaffolds with mesenchymal stem cells derived from the dental pulp: Dental Pulp Stem Cells (DPSCs). Many studies have demonstrated the high plasticity of these cells, which initially derive from the neural crest, but also their trophic ability in the repair of damaged tissues by their osteogenic and chondrocyte differentiation capacity. Moreover, these cells have better's pro-angiogenic properties than mesenchymal cells of the bone marrow (MSCs) and access to this reserve is easy since they can be obtained from extracted teeth. In this context, we have used dense collagen scaffolds seeded with DPSCs to regenerate cranial bone tissue on critical defects model. The objective is to induce a very early neo-angiogenesis for improved short-term survival of implanted cells, then stimulate the long-term maintenance of cells in the implanted neo-tissue, finally to cause osteoformation. We were able to study and validate various aspects of this theme: 1- The positive impact of the use of dense collagen scaffold as osteoconductive support, 2- Long-term follow-up of the cells after implantation in vivo (thanks to the use of a cell line constitutively expressing an intracellular fluorescence protein), 3- The positive impact of a pre-treatment with hypoxia on i/ the survival of the cells after implantation in vivo ii/ their contribution to bone regeneration / repair by orienting their differentiation towards an osteoblastic pathway, 4- The significant contribution of imaging techniques for the monitoring of animals (less sacrifice and longitudinal follow-up...) thanks to positron emission tomography (use of specific tracers of the mineralization within the scaffolds and neo-angiogenesis) and X-ray microscanner (kinetic monitoring of the quality and quantity of regenerated bone matrix) 5- Validation and confirmation of all these results by histology. Thus, these different results allowed us to respond to the working hypothesis and optimize some aspects of the cellular component. However, it remains necessary to optimize the biomaterial itself. It is indeed possible to improve the compressed collagen scaffolds that we currently use, for example by incorporating bioactive ceramics such as bioglasses or hydroxyapatite. In recent years, the study of stem cells has progressed from in vitro to in vivo. The in vivo models established to study these cells in the craniofacial area have already provided valuable information and this work is a continuation of these previous studies by seeking to build on better strategies (right characterization, environment oriented...) for the future use of DPSCs for tissue engineering purposes. In view of this work, potentiating the biomaterials of the scaffolds and combining the DPSCs with a support more adapted to their survival and their growth would considerably improve bone healing, as well as bone regeneration / repair
 
moreShow More Titles
fewerShow Fewer Titles
Audience Level
0
Audience Level
1
  General Special  
Audience level: 0.00 (from 0.00 for Nouvelles ... to 0.00 for Nouvelles ...)

Alternative Names
Yohann Wittrant wetenschapper

Languages
French (11)

English (4)