Με τον όρο «Έκτοπη Οστεοποίηση» περιγράφεται ο σχηματισμός οστού σε σημεία που υπό φυσιολογικές συνθήκες δεν υφίσταται. Τα σημεία αυτά μπορεί να είναι μύες, τένοντες ή σύνδεσμοι και γενικότερα μεσεγχυματικού τύπου μαλακά μόρια, κυρίως γύρω από τις μεγαλύτερες αρθρώσεις. Η επίκτητη μορφή της νόσου, που είναι και η πιο κοινή, εμφανίζεται μετά από μυοσκελετικούς τραυματισμούς, κακώσεις του νωτιαίου μυελού και του κεντρικού νευρικού συστήματος γενικότερα, αλλά και σε περιπτώσεις σοβαρών εγκαυμάτων. Η παθοφυσιολογία της έκτοπης οστεοποίησης παραμένει άγνωστη, αυτό που γνωρίζουμε με βεβαιότητα είναι ότι για τον σχηματισμό της απαιτούνται τρείς βασικές προϋποθέσεις που είναι α) τα οστεοπρογονικά κύτταρα, β) οι κατάλληλοι επαγωγικοί παράγοντες και γ) το ευνοϊκό οστεοεπαγωγικό περιβάλλον. Στην παρούσα εργασία με την χρήση κυτταρομετρίας ροής, δοκιμασιών με ηλεκτροχημειοφωταύγεια, Elisa και ανοσοπροσδιορισμού με χρήση Cytometric Bead Array προσδιορίσαμε τις συγκεντρώσεις των total procollagen type 1 amino-terminal propeptide (TP1NP), osteoprotegerin (OPG), β-isomerized C-terminal telopeptides (β- Crosslaps), soluble receptor activator of nuclear factor kappa-B ligand (sRANKL), N-MID osteocalcin, S100 και των κυτταροκινών IL-2, IL-4, IL-6, IL-10, INF-γ και TNF-a στον ορό ασθενών και υγιών μαρτύρων. Επιπλέον, στο ολικό αίμα προσδιορίσαμε τον πληθυσμό των θετικών στην οστεοκαλσίνη κυττάρων. Όλα τα προς μελέτη μόρια είχαν άμεση ή έμμεση σχέση με την οστική ανακατασκευή και τις φλεγμονώδεις αντιδράσεις. Συνολικά μελετήθηκαν 55 ασθενείς από τους οποίους ελήφθησαν δείγματα καθόλη την διάρκεια νοσηλείας τους. Οι ασθενείς μελετήθηκαν με βάση το είδος του τραύματος, την εμφάνιση ή όχι έκτοπης οστεοποίησης και την έκβαση της κατάστασης τους. Επιπλέον, οι επιμέρους ομάδες ασθενών μελετήθηκαν συναρτήσει του χρόνου. Τα αποτελέσματα μας έδειξαν ότι στο σύνολο των ασθενών παρατηρήθηκαν στατιστικά μειωμένα επίπεδα β- crosslaps, N-MID osteocalcin, sRANKL και S100 συγκριτικά με τους υγιείς μάρτυρες. Αντίθετα, τα επίπεδα των TP1NP, των θετικών στην οστεοκαλσίνη κυττάρων, της OPG, της INF-γ και της IL-6 ήταν στατιστικά σημαντικά αυξημένα. Επιπλέον, στατιστικά σημαντικά αυξημένα παρατηρήθηκαν τα επίπεδα του S100 στους ασθενείς που είχαν υποστεί κρανιοεγκεφαλικές κακώσεις κατά το πρώτο εικοσιτετράωρο μετά την επαγωγή της κάκωσης. Στατιστικά σημαντικά αυξημένο επίσης παρατηρήθηκε και στην ομάδα των ασθενών με κακή έκβαση συγκριτικά με τους υγιείς δότες. Στην ίδια ομάδα ασθενών παρατηρήθηκε μια γενικευμένη αύξηση των επιπέδων των κυτταροκινών που φαίνεται να σχετίζεται άμεσα με την κακή έκβαση της κατάστασης τους. Πιο συγκεκριμένα η αύξηση αυτή ήταν στατιστικώς σημαντική για τις IL-4, INF-γ και TNF-α. / Heterotopic ossification (HO) is the presence of bone in soft tissue where normally does not exist. The acquired form, which is also the most common, develops after musculoskeletal trauma, spinal cord injury or central nervous system injury and severe burns. Pathophysiology of OH still remains unclear, what we know is that the formation of ectopic bone requires three entities which are a) osteogenic precursor cells, b) inducing agents and c) an appropriate environment. In the present study using either flow cytometry, Elisa, electrochemiluminescence immunoassays or cytometric bead array assays we determined the concentrations of the osteoblast progenitors: osteocalcin positive cells in peripheral blood and the serum concentrations of total procollagen type 1 amino-terminal propeptide (TP1NP), osteoprotegerin (OPG), β-isomerized C-terminal telopeptides (β- Crosslaps), soluble receptor activator of nuclear factor kappa-B ligand (sRANKL), N-MID osteocalcin, S100 and the cytokines IL-2, IL-4, IL-6, IL-10, INF-γ and TNF-a. All measured molecules participate directly or indirectly in bone formation and metabolism and in inflammation. Our 55 patients were divided and studied in 3 different ways, regarding the kind of their injury, their outcome and the formation of HO. They were also monitored in course of time. Among our most interesting results is that patients had significantly lower levels of β- crosslaps, N-MID osteocalcin, sRANKL and S100 compared to healthy donors. On the other hand, levels of TP1NP, osteocalcin positive cells, OPG, INF-γ and IL-6 were significantly higher. S100 is significantly increased during the first 24 hours in patients who have sustained traumatic brain injury. In addition, S100 was significantly increased in patients with poor outcome compared to healthy donors. Furthermore, patients with poor outcome seem to develop a cytokine storm which is of great importance for their outcome. All measured cytokine levels were increased compared to patients with good outcome. Especially for IL-4, INF-γ, TNF-α this increase was statistically significant.

Purpose: To determine whether reduced serum levels of AHSG and elevated levels of BMP-2, 4, 7 are associated with post-arthroplasty HO. Patients: Thirty arthroplasty patients were included, 15 with evidence of peri-articular HO and 15 without (NHO). Methods: Blood samples were collected from all patients ≥ 8 weeks after arthroplasty. Analytes were measured using ELISAs. Mann-Whitney U tests were performed to compare serum analyte concentrations between HO and NHO groups, and between arthroplasty patients and healthy humans. Results: There is no difference in serum concentrations of AHSG, BMP-2, 4, 7 between HO and NHO patients. Arthroplasty patients showed significantly higher BMP-2 and BMP-4 and lower AHSG serum levels compared to healthy humans (p < 0.01). Conclusion: Baseline BMP-2, 4, 7 and AHSG serum levels are not markers of acquired HO. However, elevated baseline levels of BMP- 2, 4 and reduced levels of AHSG appear to be markers of severe inflammatory arthritis.

Purpose: To determine whether reduced serum levels of AHSG and elevated levels of BMP-2, 4, 7 are associated with post-arthroplasty HO. Patients: Thirty arthroplasty patients were included, 15 with evidence of peri-articular HO and 15 without (NHO). Methods: Blood samples were collected from all patients ≥ 8 weeks after arthroplasty. Analytes were measured using ELISAs. Mann-Whitney U tests were performed to compare serum analyte concentrations between HO and NHO groups, and between arthroplasty patients and healthy humans. Results: There is no difference in serum concentrations of AHSG, BMP-2, 4, 7 between HO and NHO patients. Arthroplasty patients showed significantly higher BMP-2 and BMP-4 and lower AHSG serum levels compared to healthy humans (p < 0.01). Conclusion: Baseline BMP-2, 4, 7 and AHSG serum levels are not markers of acquired HO. However, elevated baseline levels of BMP- 2, 4 and reduced levels of AHSG appear to be markers of severe inflammatory arthritis.

No description available.

Submitted by Maike Costa (maiksebas@gmail.com) on 2016-07-11T14:02:25Z No. of bitstreams: 1 arquivo total.pdf: 1347711 bytes, checksum: c265032cf975700b2e865f3913e22ea2 (MD5) / Made available in DSpace on 2016-07-11T14:02:25Z (GMT). No. of bitstreams: 1 arquivo total.pdf: 1347711 bytes, checksum: c265032cf975700b2e865f3913e22ea2 (MD5) Previous issue date: 2016-02-23 / The research aimed to scrutinize the memories relating to "Lighthouse and Joan Black," in Olivedos - PB (1940-1970). Space and commercial sexual exchanges, understand the "Lighthouse" among other settings, as a place and practiced as a heterotopic space deviation from theorists such as Foucault (2001) and Certeau (1994). I made use of the oral method and from there I interviewed eleven people selected according to age and knowledge of the historical facts of Olivedos linked to the Lighthouse and Joan Black. For reasons of memory discussion embasei me in theoretical as Candau (2011), with their ratings of memory and Montenegro (2007), for discussion of orality. The look of the research was guided, in the first chapter to Joan Black discussion as protagonist Lighthouse, historicizing the term "black" and their representations to understand how the name of Joan began to be accompanied by the term in the sense surname. In the second chapter problematizei the identity configurations Joan Francelino Lima, comprising from Hall (2000, p. 108), that identities are "fragmented and fractured," multiple. Also in this chapter, I presented the Joan Black tactics for meeting sexual partners and their encounter with the Catholic Church. In the third chapter, I analyzed the Lighthouse and its representations to Olivedos as "practiced place," multiple and named according to the configuration assigned by popular. In the fourth chapter, I analyzed the historical plot that led to deactivation of the lighthouse at the expense of the Municipality of urbanization process. So the historiographical operation here is woven from the space for discussion, as well as Joan identities as protagonist Lighthouse and representation of the History of Women in Olivedos-PB. Thus, these and other stories about Joan and the Lighthouse will be found here from what makes the historian and will be representations of Paraiba history / A pesquisa teve como objetivo perscrutar as memórias referentes ao “Farol e a Joana Preta,” em Olivedos - PB, (1940-1970). Espaço de trocas comerciais e sexuais, entendi o “Farol” dentre outras configurações, como um lugar praticado e como um espaço heterotópico do desvio, a partir de teóricos como Foucault (2001) e Certeau (1994). Fiz uso do método da oralidade e a partir daí entrevistei onze pessoas selecionadas de acordo com a idade e o conhecimento dos fatos históricos de Olivedos atrelados ao Farol e a Joana Preta. Para fundamentação da discussão de memória me embasei em teóricos como Candau (2011), com suas classificações da memória e Montenegro (2007), para a discussão de oralidade. O olhar da pesquisa se orientou, no primeiro capítulo para a discussão de Joana Preta enquanto protagonista do Farol, historicizando o termo “preta” e suas representações para compreender de que forma o nome de Joana passou a ser acompanhado do termo no sentido de sobrenome. No segundo capítulo problematizei as configurações identitárias de Joana Francelino de Lima, compreendendo a partir de Hall (2000, p. 108), que as identidades são “fragmentadas e fraturadas,” múltiplas. Ainda nesse capítulo, apresentei as táticas de Joana Preta para encontros com parceiros sexuais e seu encontro com a igreja católica. No terceiro capítulo, analisei o Farol e suas representações para Olivedos como “lugar praticado,” múltiplo e nomeado de acordo com a configuração atribuída pelos populares. No quarto capítulo, analisei as tramas históricas que levaram a desativação do Farol em detrimento do processo de urbanização do Município. Assim a operação historiográfica aqui tecida ocorre a partir da discussão de espaço, bem como das identidades de Joana enquanto protagonista do Farol e representação da História das Mulheres em Olivedos-PB. Dessa forma, essas e outras histórias sobre Joana e o Farol serão aqui encontradas a partir do que fabrica o historiador e serão representações da História da Paraíba.

O objetivo deste trabalho foi estudar o efeito da radioterapia na profilaxia da ossificação heterotópica (OH) em pacientes com lesão medular traumática. Foram estudados 19 pacientes (15 homens e quatro mulheres), média de idade de 30,4 ± 10,8 anos (19 a 58 anos), com lesão medular traumática. A causa mais freqüente da lesão medular foi acidente de trânsito (42,1%), seguida por queda (26,3%), ferimento por projétil de arma de fogo (21%), mergulho (5,3%) e queda de objeto sobre as costas (5,3%). Dez pacientes eram tetraplégicos (52,6%) e nove (47,4%) eram paraplégicos. Apresentavam lesão medular completa (Frankel A) 14 pacientes (73,7%) e cinco pacientes (25,3%) tinham lesão incompleta (Frankel B). Todos os pacientes incluídos no estudo realizaram cintilografia óssea inicial até um mês após o traumatismo raquimedular e apresentaram diagnóstico negativo para OH. Os pacientes foram divididos em dois grupos: nove pacientes receberam radioterapia em dose única de 8 Gy nos quadris (Grupo Estudo) e 10 pacientes compuseram o Grupo Controle. Após seis meses de seguimento clínico e radiológico, um paciente do Grupo Estudo (11%) e cinco pacientes do Grupo Controle (50%) apresentaram OH. A distribuição da freqüência do desenvolvimento da OH nos dois grupos não mostrou diferença estatística significante, apesar da menor incidência de OH no grupo submetido à radioterapia (Grupo Estudo). Concluiu-se que, com o número de pacientes estudados, não foi possível comprovar a eficácia da radioterapia na prevenção da ossificação heterotópica, ainda que haja uma forte tendência para a correlação estatística / The goal of this study was to evaluate the effect of radiotherapy on the prophylaxis of heterotopic ossification (HO) after spinal cord injury (SCI). Nineteen SCI patients were studied (15 men and four women). The mean age was 30.4 ± 10.8 years (range 19 to 58 years). The most frequent causes of lesion were traffic accident (42.1%), fall (26.3%), shot gun (21%), diving (5.3%) and objects falling on the vertebral column (5.3%). Ten patients were tetraplegics (52.6%) and nine were paraplegics. Fourteen patients (73.7%) had complete lesion (Frankel A) and five had incomplete lesion (Frankel B). All patients realized initial scintigraphy until one month after SCI and showed negative results for HO. The patients were randomized in two groups: nine patients received single dose irradiation with 8 Gy on the hips (Study Group) and 10 patients were the Control Group. After six months of clinical and radiological follow up, one patient of the Study Group (11%) and five patients of Control Group (50%) showed HO. The frequency distribution of the development of HO in both groups showed no significant statistical difference, although there was lower incidence of HO in the radiotherapy group. We concluded that, with the number of patients studied, it was no possible to prove the efficacy of radiotherapy to prevent HO, although had a strong tendency for the statistical correlation

1 PURPOSE OF THE STUDY Heterotopic ossification is frequent and well known complication after primary total hip arthroplasty. Prophylaxis is crucial, ohterwise when ossification is matured, the only treatment option is surgical removal during revision hip surgery. Prophylaxis options are pre, peri- and postoperative modalities. Effectiveness of the profylaxis step sis the aim of this disertation. The goal of Study 1 was to prove the positive side effect of tranexamic acid application to reduce the heterotopic ossification ratio after elective total hip replacement. The goal of Study 2 was to prove the reduction in HO ratio with experimental modification of anterolateral approach with electrosurgery. The goal of Study 3 was to detect the knowledge among czech orthopaedic surgeons in ossification issues and compare the results of questionnaire with german results. 2 MATERIAL AND METHODS Study 1 Cohort of 401 total hip replacements were assessed prospectivelly. Stratification of particular degrees in Brooker scale, sex, laterality and fixation type were evaluated. The average follow up was 6,10 year (40m to 113m). Hips from 2012 are referential and hips from 2016 are administered to tranexamic acid procotol. Other secondary prophylactic modalities (farmacoprophylaxy or radiotherapy), tertiary...

L’expérience de douleur et la réponse à son traitement sont teintées par les facteurs psychologiques, parmi lesquels figurent les attentes. Cette thèse propose de raffiner la compréhension de l’effet des attentes sur la régulation de la douleur par l’entremise de deux études quantitatives. D'abord, une étude expérimentale explore l'impact des attentes sur l'analgésie induite par contre-stimulation. Des volontaires sains ont été assignés à une condition contrôle ou à l’un des trois groupes au sein desquels les attentes étaient évaluées (attentes a priori) ou manipulées par l’entremise de suggestions (hyperalgésie ou analgésie). La douleur, l’anxiété et le réflexe nociceptif de flexion en réponse à des stimulations électriques ont été mesurés avant, pendant et après l’application d’un sac de glace. Les résultats suggèrent que les attentes a priori prédisent l’amplitude de l’analgésie, tandis que les attentes suggérées parviennent à potentialiser ou à bloquer les mécanismes endogènes d'inhibition de la douleur déclenchés par la contre-stimulation, indépendamment du niveau d’anxiété. Ensuite, une étude clinique se penche sur l'apport des attentes aux issues thérapeutiques de patients traités en centres multidisciplinaires de gestion de la douleur chronique. Préalablement au traitement, les attentes des patients quant aux résultats anticipés après six mois de traitement ont été évaluées. Les changements dans l’intensité douloureuse, les symptômes dépressifs, l’interférence de la douleur et la dramatisation face à la douleur, ainsi que l’impression de changement et la satisfaction face au traitement ont été évalués au suivi de six mois. Les résultats d'analyses de modélisation par équations structurelles appuient la relation prédictive entre les attentes et les issues thérapeutiques et soulignent l’impression de changement du patient comme variable médiatrice de cette association. En plus de se montrer supérieur à un modèle alternatif, ce modèle s'est avéré pertinent à travers différents sous-groupes. Dans l'ensemble, cette thèse contribue à démontrer le rôle déterminant des attentes dans le contexte de la douleur, tant au niveau physiologique que thérapeutique. Les conclusions qui se dégagent de cet ouvrage entraînent des retombées non négligeables et réitèrent la nécessité de considérer la perspective du patient afin d'optimiser les soins destinés au soulagement de la douleur. / The experience of pain and response to pain treatments are influenced by psychological factors, such as expectations. This doctoral dissertation aims at refining the comprehension of the impact of expectations on pain regulation through two quantitative studies. First, an experimental study examined the impact of expectations on analgesia induced by heterotopic noxious counter-stimulation. Healthy volunteers were assigned to a control group or one of three experimental groups in which expectations were either assessed (a priori expectations) or manipulated using suggestions (hyperalgesia or analgesia). Acute shock-pain, shock-related anxiety and the nociceptive flexion reflex were measured in response to electrical stimulations before, during and after the application of a tonic cold pain. Results suggest that a priori expectations predict the magnitude of analgesia, while manipulated expectations either enhance or block counter-stimulation analgesia, independently of anxiety processes. Subsequently, a clinical study examined the association between expectations and clinical outcomes of chronic pain patients treated in multidisciplinary pain centers. Prior to their initial visit, patients' expected treatment outcomes were assessed. Six months after their initial visit, changes in pain intensity, depressive symptoms, pain interference and pain catastrophizing, along with satisfaction with treatment and impression of change were measured. Structural equations modeling analyses support the predictive association between expectations and all clinical outcomes as well as the mediating effect of patient’s impression of change. In addition to being superior to an alternative model, the proposed model was shown to be relevant across subgroups. Overall, this thesis contributes to the demonstration of the determinant role of expectations on physiological and therapeutic processes in the context of pain regulation. These findings reiterate the need to consider the patient's perspective and offer a valuable avenue towards the optimization of treatments intended at relieving pain.

Introdução: O implante auditivo de tronco encefálico (ABI) é indicado para pacientes com perda auditiva neurossensorial severa a profunda quando há impossibilidade de realização do implante coclear. Em pacientes com surdez por meningite e ossificação coclear total bilateral, o ABI é a opção para a reabilitação auditiva. Objetivos: O estudo tem por objetivo avaliar a contribuição do ABI para os limiares audiométricos e para a percepção de fala após no mínimo 12 meses de uso em pacientes com ossificação coclear total por surdez pós-meningite, bem como descrever as complicações do procedimento. Material e métodos: Dez pacientes com surdez pósmeningite foram submetidos ao ABI por via retrolabiríntica ampliada em um centro terciário de assistência e ensino. Todos os pacientes foram operados pela mesma equipe cirúrgica e a avaliação audiológica foi realizada pelo mesmo fonoaudiólogo. Foram realizados audiometria tonal e testes de percepção de fala no pré-operatório e no mínimo 12 meses após a ativação do implante. Foram descritas as complicações associadas ao procedimento. Resultados: Oito de dez pacientes implantados permaneceram usuários. Dois pacientes não apresentaram respostas auditivas e abandonaram o seguimento. Os oito pacientes apresentaram melhora estatisticamente significativa nos limiares audiométricos, bem como nos testes de discriminação de palavras e vogais comparando pré e pós-operatório com média de seguimento de 3,3 anos. Em dois pacientes, a discriminação de sentenças em formato fechado somente no modo auditivo foi de 30% e 40%. Todos os oito usuários referiram benefício com o uso do ABI. Não houve complicações relacionadas ao procedimento. Conclusão: O ABI via retrolabiríntica ampliada é uma opção terapêutica segura para pacientes com surdez pós-meningite e com presença de ossificação coclear total bilateral, contribuindo para melhora nos limiares audiométricos e nos testes de percepção de fala. Embora a melhora nos testes audiológicos seja inferior à do implante coclear, a maioria dos pacientes do estudo usa o ABI diariamente por um período superior a 8 horas e refere benefício em seu cotidiano / Introduction: The Auditory Brainstem Implant (ABI) is an option to auditory restoration in patients with severe to profound sensorineural hearing loss who cannot be fitted with a cochlear implant. This is the only option in patients with post meningitis hearing loss presenting with bilateral total cochlear ossification. Objectives: The main objective of the study is to evaluate the hearing contribution in audiometry and speech perception tests at least 12 months after ABI implantation in patients with post-meningitis profound hearing loss. The complications of the procedure were also described. Materials and Methods: Ten patients with post-meningitis hearing loss went an ABI through extended retrolabyrinthine approach in a tertiary center by the same surgeons. The same audiologist was responsible for audiological follow-up. Tonal audiometry and speech perception tests were made before and at least 12 months after the ABI activation. The procedure complications were described for all patients. Results: Eight of ten patients became ABI users. Two patients had no auditory response and abandoned the treatment. Eight users showed benefit in tonal audiometry, word and vowels perception tests after an average follow up of 3.3 years. Two patients were able to recognize 30 and 40% of closed sentences without lip reading. There were no complications due to the ABI procedure. Conclusion: The extended retrolabyrinthine approach for the ABI is a safe surgical option for patients with post-meningitis hearing loss and totally ossified cochleae. It contributes to hearing performance in audiometry and speech perception tests. Even though the ABI results are poorer than the cochlear implants, in this study the majority of patients use their ABI more than eight hours a day and report benefits in daily activities

L'insuffisance cardiaque (IC) chronique représente la pathologie la plus fréquente nécessitant l'hospitalisation chez les patients de plus de 65 ans. La mortalité à 5 ans est estimée à plus de 50% et les enjeux en terme d’économie et de santé publique sont immenses. Parmi de nombreuses étiologies, les cardiopathies ischémiques sont la cause principale de l’IC. Sur les quinze dernières années, de nombreuses études précliniques et cliniques ont confirmé le potentiel thérapeutique des cellules souches d’améliorer la fonction cardiaque et d’atténuer le remodelage ventriculaire. Néanmoins, beaucoup de questions fondamentales liées à la thérapie régénératrice avec les cellules souches restent à résoudre. Parmi les raisons expliquant l'inefficacité de la thérapie cellulaire figurent l'intégration et la survie compromises des cellules greffées dans un microenvironnement défavorable au sein de tissus infarcis ainsi que la présence d'inflammation, de stress oxydatif, d'hypoxie sévère et de privation des nutriments. Une des approches pour améliorer la thérapie cellulaire serait d’adapter le milieu de culture des cellules in vitro en terme de concentration en oxygène afin qu’il soit plus proche des conditions in vivo. Notre étude a bien montré que le préconditionnement des cellules souches mésenchymateuses (CSMs) à l’hypoxie permettait de promouvoir la croissance cellulaire tout en gardant leur potentiel de différenciation trilignée. De plus, notre étude in vivo montrait que les CSMs cultivées en hypoxie, par rapport à celles cultivées en normoxie, présentaient un meilleur potentiel thérapeutique : amélioration de la viabilité dans la zone infarcie, augmentation de la contractilité intrinsèque et favorisation du processus d’angiogénèse, etc. Force est de constater que la récupération de la fonction cardiaque sous dispositifs d'assistance ventriculaire (bridge to recovery) pose un jalon dans le traitement de l'insuffisance cardiaque. Le phénomène « bridge to recovery » nous a permis d'approfondir la connaissance sur la physiopathologie du remodelage ventriculaire, qui était considéré comme un processus unidirectionnel. Cependant, plusieurs controverse existent sur la stratégie ‘Bridge to Recovery’. Une des questions les plus soulevées est s'il y a une limite à la durée et à l'intensité de la décharge ventriculaire afin d'éviter ses effets secondaires. Pour simuler les décharges mécaniques ventriculaires d'intensités différentes, nous avons mis au point deux modèles de transplantation cardiaque hétérotopique (TCH), cœur seul ou cœur-poumon, mimant respectivement la décharge complète et la décharge partielle. Notre étude montrait que la décharge mécanique résultait d’une atrophie myocardique, d’une réduction du métabolisme glucidique, d’une fibrose cardiaque et d’une altération de fonction cardiaque diastolique. Les effets étaient tous dépendants des intensités de décharge. Notre travail s'insère dans la thématique générale du laboratoire, qui est de développer un programme de recherche sur les approches thérapeutiques innovantes pour traiter l'infarctus du myocarde et l'IC chronique. Dans la première partie de notre projet, nous avons cherché à clarifier les effets de l'injection intramyocardique de CSMs d'origine médullaire dans la zone infarcie sur la perfusion et la fonction cardiaque (étude n°1). Nous avons ensuite étudié l'impact de la culture cellulaire en hypoxie des CSMs dérivées de moelle osseuse sur leurs caractéristiques biologiques et leur potentiel thérapeutique (étude n°2). Enfin, nous avons caractérisé les effets de décharges mécaniques d'intensités différentes sur le remodelage ventriculaire du cœur sain, sur le plan morphologique, fonctionnel et métabolique (étude n°3) / Heart failure (HF) represents one of the most frequent disease requiring hospitalization in the old population (>65 years old). The 5-year survival rates associated with heart failure are less than 50% and it results in a huge cost on social economy and public health. Ischemic heart diseases represent one of the most frequent etiologies of the heart failure. Over the last fifteen years, many preclinical and clinical studies have confirmed the therapeutic potential of stem cells to improve heart function and reduce ventricular remodeling. The failure of cell therapy can be ascribed to some extent to the poor integration and compromised survival of grafted cells in an unfavorable microenvironment in infarcted tissue which is complicated by the presence of inflammation, oxidative stress, hypoxia and severe deprivation of nutriments. Furthermore, bone marrow stem cells are physiologically located in a hypoxic environment. The adaptation of the in vitro culture medium, in terms of oxygen concentration, to the in vivo natural niche as well as the targeted area, might be one of solutions to improve the efficacy of cell therapy. One of our studies has demonstrated that preconditioning of mesenchymal stem cells (MSCs) with hypoxia could promote cell proliferation without altering the differentiation potential. What’s more, our in vivo study showed that hypoxia-preconditioned MSCs, compared with those cultured in normoxia, presented with better therapeutic efficiency, such as improvement of the myocardial viability in the infarcted area, increase of intrinsic contractility and favoring the processes of angiogenesis. The recovery of cardiac function with ventricular assist devices (bridge to recovery) is a milestone in the treatment of heart failure. The phenomenon "bridge to recovery" has enabled us to deepen the knowledge on the physiopathology of ventricular remodeling, which was considered to be a one-way process. However, the strategy of ‘Bridge to Recovery’ causes many controversies. One of the arisen questions is if there exists a limit in terms of the duration and intensity regarding the mechanical unloading in order to minimize its secondary complications. To simulate ventricular mechanical unloading of different intensities, we have developed two models of heterotopic heart transplantation (TCH), namely, heterotopic heart transplantation (HHT) and heterotopic heart-lung transplantation to simulate complete and partial unloading, respectively. Our study revealed that mechanical unloading resulted in myocardial atrophy, cardiac fibrosis and diastolic dysfunction. These secondary effects were dependent on the intensity of unloading. Our work fits into the general theme of the laboratory, which is to develop a research program on innovative therapeutic approaches to treat myocardial infarction and chronic heart failure. In the first part of our study, we sought to clarify the effects of bone marrow-derived MSCs following intramyocardial injection on the perfusion and function of the infarcted myocardium (study 1). We then investigated the impact of long-term hypoxic culture on the biological characteristics and therapeutic potential of MSCs (study 2). Finally, we explored the effects of mechanical unloading of different intensities on the structure, function and metabolism of healthy myocardium (Study 3)