Made available in DSpace on 2016-06-02T20:19:20Z (GMT). No. of bitstreams: 1 4910.pdf: 3408018 bytes, checksum: 4034688ddb3183a38d1f9c8b45afa4e8 (MD5) Previous issue date: 2013-02-22 / Universidade Federal de Sao Carlos / Muscle weakness is characterized as a significant cause of reduced physical capacity and functionality, this limitation is due to the decreased ability to produce voluntary contraction of the muscle groups in the affected hemisphere. It is a consequence of morphological and functional changes related to neural and muscular aspects. The aim of this study was to evaluate the neuromuscular performance, muscle volume and Growth Factor Insulin-like I (IGF-I) serum concentration (SC) and its Binding Protein, IGFBP-3, in subjects with chronic hemiparesis. For such, a cross-sectional study was designed. Fourteen subjects with chronic hemiparesis were evaluated for functionality performed by assessment tools Berg Balance Scale Test, Timed Up Go Adapted, Walk test 10 meters, Functional Reach Test, Fugl- Meyer Assessment, Barthel Index, Assessment of Quality of Life, Medical Outcomes Study- 36 Health Status Measurement. The subjects were allocated in the hemiparetic group (HG, 12 men). Healthy subjects (control group, CG) were paired for age, gender, height and body mass index with HG. Rectus femoris (RF), vastus medialis (VM), vastus intermedius (VI), vastus lateralis (VL), biceps femoris (BF) and semitendinosus / semimembranosus (SS) muscle volume was measured. The SC IGF-I and IGFBP-3 was quantified by ELISA. The peak torque (PT), work and power during concentric and eccentric contractions of knee extensors and flexors were evaluated using an isokinetic dynamometer at 60°/s, synchronously to record muscle activation RF, VM, VL, BF and semitendinosus (ST). For parametric data, the unpaired t test and ANOVA two-way followed by Tukey test were applied to identify statistical differences between groups and factors (dominance and condition; paretic limb: PL, non-paretic limb: NPL and control group CG). For nonparametric data was used the Mann Whitney U test followed by Bonferroni adjustment. The significance level of 5% was considered. The HG presented functional levels and CSs of IGF-I and IGFBP-3 reduced compared to the CG. The HG showed selective muscle atrophy of VM, VI, BF and SS, and also altered muscle activation between agonist and antagonist against the CG. There was a significant decrease in PT, work and power of the knee extensors and flexors for concentric and eccentric actions in the PL and NPL compared to the CG. In conclusion, hemiparetic group show weakness in the PL due to changes in neuromuscular performance, including decreased PT, power and work, and also due to changes in the agonist and antagonist muscle recruitment. These neural changes are accompanied by selective atrophy of quadriceps and hamstrings muscles and CSs decrease in IGF-I and IGFBP-3 serum concentrations. / A fraqueza muscular é caracterizada como uma importante causa da redução da capacidade física e funcionalidade, esta limitação ocorre devido à diminuição da capacidade de gerar contração voluntária dos grupamentos musculares no hemicorpo afetado. E consequência de alterações morfofuncionais relacionadas aos aspectos neurais e musculares. O objetivo deste estudo foi avaliar o desempenho neuromuscular, o volume muscular e a concentração sérica (CS) do fator de crescimento semelhante à insulina 1 (IGF-1) e de sua proteína ligante, IGFBP-3, em indivíduos hemiparéticos crônicos. Para tal, um estudo transversal foi delineado. Quatorze sujeitos com hemiparesia crônica foram submetidos a avaliações de funcionalidade realizada pelas ferramentas Escala de Equilíbrio de Berg,Teste Timed Up Go (TUG) Adaptado, Teste de caminhada de 10 metros, Teste de Alcance Funcional, índice de Desempenho Motor de Fugl-Meyer, índice de atividade de vida diária de Barthel, Escala de Avaliação da Qualidade de Vida, Medical Outcomes Study-36 Health Status Measurement. Foram alocados no Grupo Hemiparético (GH; 12 homens). Sujeitos saudáveis (Grupo Controle, GC) foram pareados por idade, gênero, altura e índice de massa corpórea com o GH. Foram mensurados o volume dos músculos reto femoral (RF), vasto medial (VM), vasto intermédio (VI), vasto lateral (VL), bíceps femoral (BF) e semitendinoso/ semimembranoso (SS). A CS de IGF-I e IGFBP-3 foi quantificada pelo método de ELISA. O pico de torque (PT), trabalho e potência concêntricos e excêntricos, dos flexores e extensores do joelho, foram avaliados em dinamômetro isocinético a 60o/s, de forma sincrônica ao registro da ativação dos músculos RF, VM, VL, BF e semitendinoso (ST). Para dados paramétricos, o teste T não pareado e Anova two-way seguida de Tukey foram utilizados para identificar diferenças estatísticas entre grupos e fatores (dominância e condição; membro parético: MP, membro não parético: MNP e membro controle: MC). Para dados não paramétricos foram utilizados o teste U de Mann Whitney seguido do ajuste de Bonferroni. O nível de significância de 5% foi considerado. O GH apresentou níveis funcionais e as CSs de IGF-I e IGFBP-3 reduzidos em relação ao GC. O GH apresentou atrofia seletiva dos músculos VM, VI, BF e SS e também demonstrou a ativação muscular alterada entre agonistas e antagonistas em relação ao GC. Houve uma diminuição significativa do PT, trabalho e potência dos flexores e extensores do joelho em ações concêntricas e excêntricas no MP em relação ao MNP e ao MC. Em conclusão, indivíduos hemiparéticos apresentam fraqueza no MP decorrente de alterações no desempenho neuromuscular, incluindo diminuição do PT, potência e trabalho, e também devido a alterações no recrutamento de músculos agonistas e antagonistas do movimento. Estas modificações neurais são acompanhadas por atrofia seletiva de músculos do quadríceps e dos isquiotibiais e por menores CSs de IGF-I e IGFBP-3.

Les facteurs de transcription de la famille p53 dans l’atrophie musculaire - Implications dans la Sclérose Latérale Amyotrophique et la cachéxie. L’atrophie musculaire est un symptôme dangereux retrouvé dans plusieurs maladies. Dans la sclérose latérale amyotrophique (SLA), une maladie neuromusculaire rare, ainsi que dans le cancer (phénomène de cachexie), l’atrophie musculaire cause le décès des patients. Les facteurs de transcription de la famille p53 sont impliqués dans de nombreux processus cellulaires, faisant face à des situations de « stress » pour les cellules. Notamment, ils peuvent induire la mort cellulaire ou promouvoir la différentiation.Nous avons constaté, à partir de modèles cellulaire et animaux de SLA et cachéxie cancéreuse, que des membres de la famille p53 sont activés dans les muscles atrophiques. Cette activation entraine l’expression de gènes cibles impliqués dans la mort cellulaire. De manière intéressante, TAp73, mais surtout TAp63, sont capables d’activer la transcription d’un effecteur de l’atrophie musculaire appelé MuRF1, démontrant que la famille p53 peut participer activement à l’atrophie en induisant la dégradation des fibres musculaires.De plus, nous avons utilisé nos modèles animaux pour identifier une nouvelle approche contre l’atrophie musculaire. Ainsi, nous avons identifié un dérivé de tocophérol avec des propriétés thérapeutiques intéressantes. / The p53 family of transcription factors in muscular atrophy - Involvements in Amyotrophic Lateral Sclerosis and cachexia Muscular atrophy is a dangerous condition found in several diseases. In amyotrophic lateral sclerosis (ALS), a rare neuromuscular disease, as well as in cancer (phenomenon of cachexia), muscular atrophy can be fatal to patients.The transcription factors from the p53 family are involved in several cellular processes, facing cellular “stress” situations. Most notably, they can induce dell death or promote differentiation.We found, using cellular and mouse models of ALS and cachexia, that members of the p53 family are induced during muscular atrophy. This induction leads to the expression of canonnic target genes involved in cell death. Interestingly, TAp73, but especially TAp63, are able to activate the transcription of an effector or muscular atrophy called MuRF1. This proves that the p53 family cand participate in muscular atrophy by promoting the breakdown of muscle fibres.In addition, we used our mouse models to identifiy a new approach agains muscular atrophy.Indeed, we identified a derivative of tocopherol with interesting therapeutical proprieties.

Hipotrofía nos músculos que estabilizam a coluna tem sido identificada nos pacientes com lombalgia. Entretanto, não se sabe se a perda muscular é causa ou conseqüência desta disfunção, nem se ela é influenciada pelo tipo de alteração discal que o indivíduo apresenta. Este estudo testou a hipótese de que a hipotrofía dos pacientes com lombalgia seja dependente do tipo de alteração discal. Para avaliar a condição muscular em diferentes tipos de alteração discal, optou-se por um estudo retrospectivo e por uma seleção aleatória de 78 exames de ressonância magnética de indivíduos com lombalgia. Em cada exame foram realizadas medidas quantitativas da porcentagem de gordura na área de secção transversa dos mm. multífidus e psoas, nos três últimos níveis da coluna lombar. A alteração discal foi encontrada em 95% dos exames, sendo o abaulamento o achado de imagem mais freqüente, seguido pela protrusão discal. A porcentagem de gordura variou conforme o tipo de alteração discal. Nos níveis com abaulamento há em ambos os músculos estudados 6% a mais de tecido gorduroso do que nos níveis onde há protrusão e esta diferença foi estatisticamente significante. Músculos nos níveis onde há protrusão sem fissura no anel fibroso apresentaram maior substituição gordurosa do que aqueles onde há protrusão com fissura. A porcentagem de gordura foi influenciada por características anatômicas como músculo estudado e nível da coluna, e por características como idade e sexo dos sujeitos. Estes resultados indicam que a hipotrofía muscular em pacientes com lombalgia não é um processo uniforme e generalizado, mas sim correlacionado a diferentes variáveis, entre elas o tipo de alteração discal que o paciente apresenta. / Low back pain patients present atrophy on muscles responsible for spine stabilization. However, it is not clear if muscle waste is related to the cause or if it is a consequence of this disfunction. Nor it is clear if muscle athophy is affected by the type of disc pathology. This study tested the hypothesis that muscle waste in low back pain patients influenced by the type of disc derangement. Magnetic resonance scans of 78 low back pain patients were randomly analysed. Cross sectional area percentage of fat tissue in multifidi and psoas major muscles was measured on the lower levels of the lumbar spine. Disc pathology was found in 95% of the exams and disc bulge was the most frequent abnormality, followed by disc protrusion. Fat percentage varied according to disc pathology and this difference was statistically significant. Muscles on levels with disc bulge presented 6% more fat deposits than muscles on levels with disc protrusion. Muscles on levels with discs without anular tear present more fat infiltration than muscles on levels with anular tear. Fat percentage was also influenced by anatomic aspects such as evaluated muscle and spine level, and sample characteristics as age and sex. The results indicated that muscle atrophy in low back pain patients is not a uniform and generalized feature. It is correlated to different variables, such as type of disc pathology

A estimulação elétrica neuromuscular (EENM) é um importante recurso utilizado na medicina esportiva para acelerar processos de recuperação. O objetivo deste estudo foi analisar os efeitos da EENM durante a imobilização do músculo gastrocnêmio, em posições de alongamento (LP) e encurtamento (SP). Para tanto, 60 ratas fêmeas jovens WISTAR foram distribuídas em seis grupos e acompanhadas durante 7 dias: controle (C), eletroestimuladas (EE), imobilizadas em encurtamento (ISP), imobilizadas em alongamento (ILP), imobilizadas em encurtamento e eletroestimuladas (ISP+EE) e imobilizadas em alongamento e eletroestimuladas (ILP+EE). Para a imobilização, o membro posterior direito foi envolvido por uma malha tubular e ataduras de algodão juntamente à atadura gessada. A EENM foi utilizada com uma freqüência de 50 Hz, 10 minutos por dia, totalizando 20 contrações em cada sessão. Após 7 dias os animais foram submetidos à eutanásia e os músculos gastrocnêmios foram retirados para a realização do ensaio mecânico de tração em uma máquina universal de ensaios (EMIC®). A partir dos gráficos carga versus alongamento foram calculadas as seguintes propriedades mecânicas: alongamento no limite de proporcionalidade (ALP), carga no limite de proporcionalidade (CLP), alongamento no limite máximo (ALM), carga no limite máximo (CLM) e rigidez. As imobilizações SP e LP promoveram reduções significativas (p<0,05) nas propriedades de ALP, CLP, ALM e CLM sendo mais acentuada, principalmente, no grupo ISP. Quando utilizada a EENM, houve acréscimo significativo (p<0,05) destas propriedades somente no grupo ISP. Já, em relação à rigidez, foi observada redução significativa (p<0,05) somente do grupo C para o grupo ISP. Quando utilizada a EENM, a rigidez do grupo ILP+EE foi significativamente (p<0,05) maior e mais próxima do grupo C que a do grupo ISP+EE. Neste modelo experimental, a imobilização dos músculos em alongamento atrasou a queda das propriedades e a estimulação elétrica, contribuiu para a manutenção das propriedades mecânicas durante o período de imobilização, principalmente no grupo ILP+EE. / The neuromuscular electric stimulation (NMES) is an important tool used in sport medicine to accelerate the recovery process. The objective of this study was to analyze the effects of NMES during the immobilization of the gastrocnemius muscle, in lengthened (LP) and shortened positions (SP). Sixty young female rats WISTAR were distributed into six groups and followed for 7 days: control (C), electric stimulation (ES), immobilized in shortened (ISP), immobilized in lengthened (ILP), immobilized in shortened and electric stimulation (ISP+ES) and immobilized in lengthened and electric stimulation (ILP+ES). For the immobilization, the right hind limb was involved by a tubular mesh and cotton rolls and plaster. NMES was used in a frequency of 50 Hz, 10 minutes a day, totaling 20 contractions in each session. After 7 days the animals were killed and their gastrocnemius muscles of the right side were submitted to a mechanical test in traction in an universal test machine (EMIC®). From the curves load versus elongation the following mechanical properties were obtained: elongation in the yield limit (EPL), load in the yield limit (LPL), elongation in the ultimate load (EUL), ultimate load (UL) and stiffness. The immobilizations SP and LP promoted significant reductions (p<0,05) in the properties of EPL, LPL, EUL and UL being more accentuated mainly in group ISP. When used NMES, there was significant increment (p<0,05) of such properties only in group ISP. As for stiffness, significant reduction was observed (p<0,05) only of the group C for group ISP. When the NMES was used, the stiffness of group ILP+EE was significantly (p<0,05) higher and closer to group C than for group ISP+EE. We conclude that in this experimental model the immobilization of the muscles in the lengthened position delayed the reduction of the properties and the electric stimulation contributed to the maintenance of the mechanical properties during the immobilization period, mainly for group ILP+ES.

Les pathologies du motoneurone sont caractérisées par une atteinte progressive des motoneurones au niveau de la corne antérieur de la moelle épinière. Au delà de cette susceptibilité anatomique commune, qui est responsable d’une atteinte motrice progressive et diffuse dans ces pathologies, d’autres systèmes neurologiques sont touchés. La dégénérescence du faisceau corticospinal est une caractéristique classique dans la sclérose latérale amyotrophique, qui est la maladie du motoneurone la plus commune chez l’adulte. Cependant, il est de plus en plus reconnu que la SLA est une maladie multisystémique. En particulier, une atteinte précoce du système sensoriel a été démontrée dans la modèle animal de la SLA ainsi que dans l’amyotrophie spinal liée à la mutation du gène SMN1 (survival motor neuron 1 en anglais). Chez les patients, l’imagerie par résonance magnétique (IRM) a émergé comme l’approche la plus performant à l’étage cérébral, permettant d’extraire des indices quantitatifs sur la perte neuronale, la dégénérescence axonale et la démyélinisation dans les pathologies neurodégénératives. Cependant, l’investigation de l’étage médullaire dans ces pathologies est difficile à mener à cause des nombreux défis techniques et méthodologiques que représente l’IRM de la moelle épinière.L’objectif de ce projet de thèse a été d’utiliser l’approche IRM multiparamétrique au niveau de la moelle épinière pour analyser les structures de la matière grise et blanche qui sont atteintes dans deux des pathologies du motoneurone les plus répondues, c’est-à-dire la SLA et la SMA, leurs altérations au cours du temps et leurs corrélations fonctionnelles avec les données cliniques et électrophysiologiques. / Degenerative motor neuron diseases (MND) are characterized by a progressive dysfunction and loss of ventral horn motor neurons of the spinal grey matter. Beyond this common anatomical susceptibility, which is responsible for a progressive and diffuse weakness, other neurological systems are also impaired. The corticospinal tract (CST) degeneration is a classical feature of amyotrophic lateral sclerosis (ALS), which is the most common adult onset motor neuron disease, but a more widespread multisystem involvement is now well recognized. In particular, early sensory system involvement has been demonstrated in animal models of ALS and also of survival motor neuron 1 gene linked spinal muscular atrophy (SMN1-linked SMA). In human patients, magnetic resonance imaging (MRI) has emerged as the most powerful approach at the brain level to extract quantitative data on neuronal loss, axonal degeneration and demyelination in degenerative conditions. Studies at the spinal cord levels are scarce mainly because of technical and methodological difficulties. The objective of the present thesis project was to use a multi-parametric MRI approach at the spinal cord level to analyze grey and white matter structures that are impaired in two most common MND, i.e. ALS and SMN1-linked SMA, their temporal alterations during the disease course and the functional correlates, as assessed by clinical and electrophysiological examinations.

Spinal muscular atrophy (SMA) is the leading genetic cause of death of young children. It is an autosomal recessive disease caused by the mutation and/or the deletion within the ubiquitously expressed survival motor neuron 1 (SMN1) gene. SMA pathology is characterized by spinal cord motor neuron degeneration, neuromuscular junction (NMJ) defects and muscular atrophy. Upon disease onset, SMA patients progressively become paralyzed and in the most severe cases, they die due to respiratory complications. Over the years, it has become clear that SMN is a multi-functional protein with important roles in small nuclear ribonucleoprotein (snRNP) assembly, RNA metabolism, axonal outgrowth and pathfinding, mRNA transport as well as in the functional development of NMJs, skeletal muscle and cardiac muscle. However, it remains unclear which of these functions, and the respective perturbed molecular pathways, dictate SMA pathogenesis. Here, we have established Smn-depleted PC12 cells and an intermediate SMA mouse model to characterize a role for Smn in the regulation of actin cytoskeleton dynamics. We find that Smn depletion results in the increased expression of profilin IIa and active RhoA (RhoA-GTP) as well as the decreased expression of plastin 3 and Cdc42. Importantly, the inhibition of rho-kinase (ROCK), a direct downstream regulator of RhoA, significantly increased the lifespan of SMA mice and shows beneficial potential as a therapeutic strategy for SMA. In an addition, we have uncovered a muscle- and motor neuron-independent role for SMN in the regulation of pancreatic development and glucose metabolism in SMA mice and type 1 SMA patients. This finding highlights the importance of combining a glucose tolerance assessment of SMA patients with their existing clinical care management. Thus, our work has uncovered two novel and equally important roles for the SMN protein, both of which contribute significantly to SMA pathogenesis.

INTRODUÇÃO: Existem poucos estudos demonstrando que anormalidades musculares esqueléticas em pacientes com insuficiência cardíaca crônica persistem meses após o transplante cardíaco. No presente estudo, objetivamos avaliar massa muscular, e força muscular periférica e respiratória em pacientes no pré-transplante cardíaco, e no seguimento precoce (6 meses) e tardio (1,5 e 3 anos) pós-transplante cardíaco. Objetivamos verificar ainda a correlação entre força muscular periférica e respiratória em pacientes no pré e pós-transplante cardíaco. Comparamos, por fim, os dados de pacientes do pré-transplante cardíaco com um grupo controle de indivíduos saudáveis sem doença cardíaca. MÉTODOS: Tratou-se de estudo prospectivo do tipo coorte. Foram selecionados todos os pacientes em lista de espera para transplante cardíaco do Hospital de Messejana, do período de agosto de 2011 a março de 2013. Avaliamos idade, gênero, causas da insuficiência cardíaca, hipertensão, diabetes, tempo de espera na lista, tempo de internamento pós-transplante, tempo de ventilação mecânica, medida da força muscular respiratória, da força muscular periférica, da espessura do adutor do polegar, média bilateral da área de secção transversal do músculo psoas maior, índice de massa corporal e creatinina em todos os pacientes do estudo e no grupo controle. As variáveis de massa e força muscular foram medidas por meio de tomografia computadorizada, paquimetria, manovacuometria e dinamometria. RESULTADOS: Foram encontrados 25 pacientes elegíveis e 23 foram incluídos. Ocorreram 8 óbitos no seguimento precoce, 4 no seguimento tardio e, ao final de 3 anos de seguimento, 11 pacientes sobreviveram com enxerto funcionando. Foram selecionados 23 indivíduos saudáveis para o grupo controle, pareados para gênero, idade, peso e altura. Quando comparamos as variáveis de massa e força muscular dos pacientes do grupo pré-transplante cardíaco com o grupo controle de indivíduos saudáveis foram encontradas diminuição da força muscular periférica (27,0 kg/f vs. 38,2 kg/f), da área de secção transversal do músculo psoas ( 1.238,9 mm2 vs. 1.533,1 mm2) da espessura do músculo adutor do polegar (16,5 mm vs. 23,9 mm), da força muscular inspiratória (60,2 cmH2O vs. 94,8 cmH2O) e da força muscular expiratória (75,2 cmH2O vs. 102,17 cmH2O) nos pacientes do grupo pré-transplante cardíaco. Na comparação entre os períodos pré-transplante cardíaco, seguimento precoce e seguimento tardio pós-transplante cardíaco houve aumento estatisticamente significante (p < 0,001) das seguintes variáveis: força muscular periférica (27,3 kg/f vs. 34,7 kg/f), da área de secção transversal do músculo psoas ( 1.305,4 mm2 vs. 1.431,3 mm2) da espessura do músculo adutor do polegar (15,9 mm vs. 20,2 mm), da força muscular inspiratória (59,5 cmH2O vs. 90,9 cmH2O) e da força muscular expiratória (79,5 cmH2O vs. 101,8 cmH2O) nos 11 pacientes sobreviventes. Ao final do seguimento tardio pós-transplante cardíaco todas as variáveis de massa e força muscular atingiram níveis semelhantes àqueles do grupo controle, exceto a espessura do músculo adutor do polegar. CONCLUSÃO: Os achados demonstraram haver sarcopenia em pacientes no pré-transplante cardíaco, visto que houve diminuição da massa muscular e da força muscular periférica e respiratória confirmando a presença de dois critérios, requisito para fazer o diagnóstico de sarcopenia. O transplante cardíaco proporcionou aumento da força muscular respiratória, da força muscular periférica, da espessura do músculo adutor do polegar e aumento da massa muscular do psoas / INTRODUCTION: There are few studies demonstrating that skeletal muscle abnormalities in patients with chronic heart failure persist for months after heart transplantation. In this study, we aimed to evaluate muscle mass, and peripheral and respiratory muscle strength in patients in pre-heart transplantation, and in the early (6 months) and late (1.5 to 3 years) follow-up after heart transplantation. We also aimed to verify the correlation between peripheral and respiratory muscle strength in patients before and after heart transplantation. Finally, we compared the pre-heart transplantation patients\' data with a control group of healthy individuals without heart disease. METHODS: It was a prospective cohort study. We selected all patients on the waiting list for heart transplantation of Messejana\'s Hospital from August 2011 to March 2013. Age, gender, cause of heart failure, hypertension, diabetes, period on the waiting list, post-transplantation hospitalization time, mechanical ventilation time, measurements of respiratory muscle strength (maximum inspiratory muscle strength and maximum expiratory muscle strength), peripheral muscle strength (hand grip strength), adductor pollicis muscle thickness, the bilateral average of the major psoas muscle cross-sectional area, body mass index and serum creatinine were assessed in all the patients in the study and in control groups. Mass and muscle strength variables were measured using computed tomography, pachymetry, manometry and dynamometry. RESULTS: We found 25 eligible patients and 23 were included. There were 8 deaths in the early follow-up period; by the end of 3-year follow-up there were 11 surviving patients with functioning graft. We selected 23 healthy subjects for the control group, matched for gender, age, weight and height. When we compared the variables mass and muscle strength of the pre heart transplant patients with healthy control subjects were found decreased peripheral muscle strength (hand grip strength) (27.0 kg/f vs. 38.2 kg/f), of the psoas muscle\'s cross-section area (1238.9 mm2 vs. 1533.1 mm2), the adductor pollicis muscle thickness (16.5 mm vs. 23.9 mm), maximum inspiratory muscle strength (60.2 cmH2O vs. 94 8 cmH2O) and maximum expiratory muscle strength (75.2 cm H2O vs. 102.17 cmH2O) in patients in the pre heart transplant group. Comparing the pre-heart transplant periods, the early and late heart transplantation follow-up there was a statistically significant increase (p < 0.001) the following variables: peripheral muscle strength (hand grip strength) (27.3 kg / f vs. 34.7 kg / f ), the psoas muscle\'s cross-sectional area (1305.4 vs. 1431.3 mm 2 mm 2) the adductor pollicis muscle thickness (15.9 mm vs. 20.2 mm), maximum inspiratory muscle strength (59.5 cmH2O vs. 90.9 cm H2O) and maximum expiratory muscle strength (79.5 cm H2O vs. 101.8 cm H2O) in the 11 surviving patients. At the end of post-heart transplant late follow-up all variables mass and muscle strength reached similar levels to those of the control group, except the adductor pollicis muscle thickness. CONCLUSION: The findings showed that there was sarcopenia in patients in pre-heart transplantation period, since there was a decrease in muscle mass and a decrease in muscle strength of peripheral and respiratory muscles confirming the presence of at least two criteria, a requirement to make the diagnosis of sarcopenia. Heart transplantation has provided increased respiratory muscle strength, increased peripheral muscle strength, increased the adductor pollicis muscle thickness and increased psoas muscle mass

Les amyotrophies spinales infantiles (ASI) de type 1 (subdivisées en type 1 vrai et 1 bis), sont des maladies neuromusculaires qui paralysent progressivement l’enfant, mettant en jeu son pronostic vital lors de l’atteinte des muscles respiratoires. L’assistance respiratoire invasive par trachéotomie évite son décès, mais soulève un questionnement éthique compte-tenu de la gravité du handicap moteur. L’ASI de type 1 vrai représente la forme la plus grave. Ces enfants étant totalement paralysés et pouvant très difficilement communiquer, ils ne sont pas trachéotomisés et décèdent dans la petite enfance. Le type 1 bis étant un peu moins sévère avec possibilité pour l'enfant de s'exprimer, les équipes médicales françaises se positionnent généralement en faveur de la trachéotomie, ce qui ne fait pas l’unanimité au niveau international. Cette question soulève donc un questionnement éthique, car lorsque les professionnels évaluent la vie qu’elle va imposer à l’enfant ainsi qu’à sa famille, ils redoutent éventuellement qu’elle représente une obstination déraisonnable de soins. Mais qu’ils y soient favorables ou au contraire défavorables, ils ne peuvent décider seuls de la démarche à entreprendre et il leur est impossible d’exclure les parents du processus décisionnel. Au regard de ces problématiques, ce travail porte une attention particulière aux parents de ces enfants avec 2 thématiques de recherche approchées par des études qualitatives : L’une sur leur vécu de la prise de décision de recourir ou non à la trachéotomie, avec la réalisation de deux études phénoménologiques : une auprès de parents dont l’enfant est décédé sans trachéotomie, l’autre auprès de parents ayant un enfant vivant avec une trachéotomie. L’autre sur les conséquences de la trachéotomie pour l’enfant et sa famille, menée auprès de mamans d’enfants trachéotomisés. Les résultats de ces travaux mettent en exergue les difficultés d’être exposé à une telle prise de décision en tant que parent, et le cheminement ainsi que les évènements qui les mènent à un moment ou un autre à se positionner sur la question. Ils interrogent également la place dans la société de l’enfant tétraplégique, trachéotomisé et ventilo-dépendant. Son état représente un paroxystique degré de vulnérabilité physique et sociale, considérablement majoré par le fait qu’il ne peut pas, comme l’adulte, tenter de prendre sa vie en main. Ce sujet n’étant jamais évoqué dans la presse non spécialisée, ces situations restent souvent dans l’ombre alors qu’elles représentent des vies qui ont grandement besoin de tolérance et de solidarités humaines (individuelles et collectives) pour ne pas s’éteindre. Ces dernières déterminent en partie le devenir de l’enfant et favorisent ou au contraire, empêchent la création de sa place légitime au sein de la société / Childhood spinal muscular atrophy (SMA) type 1 (divided into true type 1 and 1a), are progressively paralyzing neuromuscular diseases that afflict children, affecting their prognosis when respiratory muscles are involved. Invasive ventilatory support by tracheotomy prevents death, but raises ethical issues in view of the severity of motor impairment. SMA type 1 represents the most severe form. These children are completely paralyzed and communicate only with great difficulty; they are not tracheotomized and die in infancy. For Type 1a, being somewhat less severe with the possibility for children to express themselves, French medical teams are generally positioned in favor of tracheotomy, which is not an internationally unanimous approach. This question raises an ethical issue because when professionals assess the life that will result for the child and family, they sometimes fear that it represents unreasonable and excessive care. Whether their views are favorable or unfavorable regarding ventilatory support, they cannot decide alone which approach should be undertaken; it is impossible to exclude parents from decision making. Given these issues, this study pays particular attention to parents of children with two research themes through qualitative research : One focus was on parents’ experience of deciding whether or not to accept tracheotomy, which was examined through two phenomenological studies: one with parents whose child died without a tracheotomy, the other with parents with children living with a tracheotomy. The other focus was on the consequences of a tracheotomy for the child and family, conducted among mothers of children with tracheotomies. The results of these studies highlight the difficulties of being faced with such a decision as a parent, and the journey and events that lead to one point or another on this issue. They also question the place in society of the quadriplegic child with a tracheotomy and ventilator dependence. The child’s condition represents a paroxysmal degree of physical and social vulnerability, significantly increased by the fact that he/she cannot, as adults, take his/her life in hand. This subject is never mentioned in the lay press; these situations often remain in the shadows while there are lives that are in dire need of tolerance and human solidarity (individual and collective) to not be extinguished. This partly determines the future of the child and promotes or, on the contrary, prevents the creation of his/her rightful place in society.

No description available.

Spinal muscular atrophy (SMA), the leading genetic cause of infant death, is a motor neuron disease (MND) caused by mutations or deletion of the survival motor neuron 1 (SMN1) gene, which codes for SMN protein. While SMN protein is ubiquitously expressed and crucial for the survival of all types of cells, motor neuron (MN) degeneration is the primary pathological result of SMN protein reduction. The origin of this selective vulnerability in SMA remains unsolved. In agreement with the large number of identified SMN binding partners, SMN has been linked to a vast number of cellular functions (e.g. splicing, transport and local translation of messenger ribonucleic acid (mRNA), endocytosis or autophagy), many of which impact protein homeostasis. The correct functionality of the mentioned housekeeping processes is critical for all cellular types, and thus it is puzzling why MNs are especially vulnerable to the reduction of SMN protein. The role that SMN plays in the regulation of the autophagy-lysosomal pathway (ALP), a major cellular degradative system, is not well studied. Recent studies have shown that SMN deficient cells display defects in the catabolic endosomal-autophagy pathway, leading to accumulation of autophagosomes (APs) and their undegraded cargo. The fact that APs form properly in SMN deficient cells, but are not correctly cleared from the cell, suggests a failure in the final step of the ALP, the AP degradation mediated by lysosomes. The main goal of this thesis was therefore to investigate the molecular mechanisms underlying the regulation of ALP by SMN, and whether and how alterations in this axis can result in the selective degeneration of MNs in SMA. To this end, MNs, derived from human induced pluripotent stem cell (hiPSC) lines, generated from patients affected by SMA and healthy individuals, have been used to uncover specific alterations in the ALP upon SMN reduction and the underlying molecular factors. Utilizing image-based experiments, I was able to discover that SMA MNs display a reduced number of lysosomes, compared to healthy MNs and isogenic controls, which leads to a defective AP-lysosome fusion. Interestingly, the remaining reduced pool of lysosomes in these SMA MNs exhibits an increased acidity, protease activity and axonal transport, none of which, seems to be sufficient to prevent MN loss. These findings demonstrate that SMN loss leads to a dysregulation of several key elements of the ALP, ultimately resulting in a reduced capacity of SMA MNs to degrade superfluous and potentially harmful material and to obtain essential building blocks from its recycling. To assess if the observed alterations in the ALP are specific to MNs or shared among other neuronal types that are typically not affected upon SMN reduction, I generated cortical neurons (CxNs) from the same hiPSCs and performed similar studies. These SMA CxNs did not show a reduction in the number of lysosomes or a change in their acidification status. Therefore, these findings indicate that the defective ALP upon SMN protein deficiency seems to be specific to spinal MNs and does not occur in all neuronal types. To explore the potential origin of the observed ALP abnormalities in SMA MNs, I focused on the transcription factor EB (TFEB), a master regulator of lysosomal biogenesis and autophagy functionality. The main inhibitor of TFEB activity, the mammalian target of rapamycin (mTOR), has been previously shown to be over-activated in SMA, but whether SMN protein exerts any regulation over TFEB had not been explored before. During this thesis, I found that TFEB, and several of its downstream targets essential for autophagy function, are indeed dysregulated in SMA. The decline in the expression levels of several TFEB target genes that I have discovered in SMA MNs confirmed the reduced activity of TFEB in these cells. In addition, overexpression of TFEB in SMA MNs and in an in vivo SMA zebrafish model did ameliorate the reduced survival of MNs and axonal dystrophy characteristic of these models, respectively, further confirming TFEB as a potential key protein in the loss of protein homeostasis of SMA MNs. These results also strengthened the observed over-activation of mTOR as potential key link between SMN reduction, defective ALP and MN vulnerability, but the mechanistic origin of this abnormally active mTOR in SMA MNs is unknown. I was able to find a potential candidate for this link in a previously published RNA-sequencing dataset, namely the mTOR activating tumor protein, translationally-controlled 1 (TPT1). A previous study showed that TPT1 acts as a negative regulator of basal autophagy, through activation of mTOR. Intriguingly, TPT1 was over-represented in the mentioned dataset. Upon TPT1 knock down in SMN deficient cells, autophagy flux and MN survival was ameliorated, which suggests TPT1 as a promising candidate downstream of SMN loss to revert the lysosomal and autophagic defects identified in SMA MNs. The dysregulation of the ALP, including alterations in TFEB levels, has been linked to the appearance of toxic protein aggregates in many neurodegenerative diseases (NDs). I therefore wondered if the observed reduction in ALP functionality in SMA MNs could result in an overlooked aberrant protein aggregation phenotype, similar to other NDs. Indeed, I showed in this study that three commonly used markers for protein aggregation, p62 protein - an autophagy cargo that accumulates when autophagy does not function properly -, vimentin - an integral component of the aggresome structure - and Proteostat - a fluorescent dye that binds protein aggregates - were increased in SMA hMNs compared to healthy controls. Together, these findings show that SMA MNs selectively display an accumulation of undegraded material, including APs, likely due to a dysregulation of TFEB, which additionally leads to a reduction in the number of lysosomes per MN and therefore to a decreased proteostasis capacity. Additionally, clear signs of intracellular protein aggregation were observed in SMA MNs, which could further increase the vulnerability of these neurons. These phenomena seem to be specific to MNs as no similar decrease in survival or lysosomal defects were observed in SMA CxNs and could at least partially explain the observed selective vulnerability of spinal MNs in SMA patients. Collectively, the presented Ph.D. thesis demonstrates that SMN protein regulates the correct activity of the ALP, and that low SMN levels result in the dysfunction of this critical pathway, specifically in MNs. This study highlights the importance of this axis in the survival of MNs, and places it in the spotlight for further research aiming to improve MN health, not only in SMA but potentially as well for other MNDs.