Objetivos. Alta prevalência de síndrome metabólica (SM) tem sido descrita recentemente em diferentes miopatias inflamatórias idiopáticas, mas não em síndrome antissintetase (SAS). Portanto, avaliamos a frequência de SM em SAS e a associação de SM com os fatores de risco de doenças cardiovasculares e as características da doença relacionada à SAS. Métodos. Trata-se de um estudo transversal, único centro, no qual 42 pacientes consecutivos com SAS foram pareados por sexo, idade, etnia e índice de massa corporal com 84 indivíduos saudáveis, no período de 2012 a 2015. Todos os pacientes apresentavam pelo menos quatro dos cinco itens dos critérios de Bohan e Peter (1975) e também os seguintes sinais e/ou sintomas no início da doença: artrite, acometimento pulmonar, fenômeno de Raynaud, febre, \"mãos de mecânico\" e autoanticorpos antissintetases. O status da SAS foi avaliado, baseando-se nos questionários de International Myositis Assessment and Clinical Studies Group (IMACS). Os dados clínicos, laboratoriais e terapêuticos foram coletados por meio de um protocolo padronizado. A SM foi definida de acordo com a Joint Interim Statement de 2009. A análise de adipocitocinas séricas (adiponectina, leptina e resistina) foi feita através de método padronizado, enquanto que a análise de resistência insulínica foi realizada através do método de Homeostatic Model Assessment (HOMA). Resultados. A idade mediana dos pacientes com SAS foi de 41,1 anos, com predominância de etnia branca e de sexo feminino. Os pacientes apresentaram prevalência maior de SM (42,9% vs. 13,1%; P < 0,001) e valor maior de resistência insulínica, quando comparados ao grupo controle. Além disso, os pacientes apresentaram maior nível sérico de resistina, em contraste com um menor nível de leptina e similar de adiponectina, quando comparado ao grupo controle. Em uma análise adicional, quando foram comparados os pacientes com SM (N=18) e sem (N=24) SM, os primeiros apresentavam maior idade (48,7 vs. 35,4 anos; P < 0,001), com duração semelhante da doença, status da doença, esquema terapêutico, resistência insulínica e nível sérico de adipocitocinas. Conclusões. Maior frequência de SM e maior valor de resistência insulínica foram observados em pacientes com SAS, com alto nível sérico de resistina e baixo nível de leptina. Além disso, os pacientes de SAS com SM apresentavam idade mais avançada, a exemplo do que ocorrem com outras miopatias inflamatórias idiopáticas com SM / Objectives. A high frequency of metabolic syndrome (MetS) has been recently described in different idiopathic inflammatory myopathies, but not for antisynthetase syndrome (ASS). Therefore, we determined the prevalence of MetS in ASS and the association of MetS with the risk factors of cardiovascular diseases and with ASS-related disease characteristics. Methods. A cross-sectional single center study of 42 consecutive patients with ASS was conducted from 2012 to 2015. For the control group, 84 healthy individuals were matched with patients for gender, age, ethnicity and body mass index-matched, in the same period. All patients had at least four of five items of Bohan and Peter\'s criteria (1975) and also the follow signal and/or symptoms at onset of disease: arthritis, pulmonary involvement, Raynaud\'s phenomenon, fever, \"mechanics\' hands\" and antisynthetase autoantibodies. The disease status was defined, basing on the International Myositis Assessment and Clinical Studies Group (IMACS) questionnaires. Clinical, laboratory and treatment data were collected using a standardized protocol. MetS was defined according to the 2009 Joint Interim Statement. The serum adipocytokine analysis (adiponectin, leptin and resistin) was performed by standardized method, whereas the insulin resistance was performed by Homeostatic Model Assessment (HOMA) method. Results. ASS patients had a median age of 41.1 years and were predominantly female and of white ethnicity. The patients had a higher frequency of MetS (42.9% vs. 13.1%; P < 0.001) and of insulin resistance than controls. Moreover, patients had higher resistin, lower leptin and similar adiponectin levels in serum than controls. Further analysis of the ASS patients with (N=18) and without (N=24) MetS revealed that individuals with the syndrome were older (48.7 vs. 35.4 years; P < 0.001) age at disease onset and had similar disease duration, disease status, treatment, insulin resistance and serum adipocytokine levels. Conclusions. The prevalence of MetS was high in patients with ASS, who also had serum resistin and low leptin levels. Moreover, ASS patients with MetS were older at disease onset, mirroring findings seen in other idiopathic inflammatory myopathies

Objetivos. Alta prevalência de síndrome metabólica (SM) tem sido descrita recentemente em diferentes miopatias inflamatórias idiopáticas, mas não em síndrome antissintetase (SAS). Portanto, avaliamos a frequência de SM em SAS e a associação de SM com os fatores de risco de doenças cardiovasculares e as características da doença relacionada à SAS. Métodos. Trata-se de um estudo transversal, único centro, no qual 42 pacientes consecutivos com SAS foram pareados por sexo, idade, etnia e índice de massa corporal com 84 indivíduos saudáveis, no período de 2012 a 2015. Todos os pacientes apresentavam pelo menos quatro dos cinco itens dos critérios de Bohan e Peter (1975) e também os seguintes sinais e/ou sintomas no início da doença: artrite, acometimento pulmonar, fenômeno de Raynaud, febre, \"mãos de mecânico\" e autoanticorpos antissintetases. O status da SAS foi avaliado, baseando-se nos questionários de International Myositis Assessment and Clinical Studies Group (IMACS). Os dados clínicos, laboratoriais e terapêuticos foram coletados por meio de um protocolo padronizado. A SM foi definida de acordo com a Joint Interim Statement de 2009. A análise de adipocitocinas séricas (adiponectina, leptina e resistina) foi feita através de método padronizado, enquanto que a análise de resistência insulínica foi realizada através do método de Homeostatic Model Assessment (HOMA). Resultados. A idade mediana dos pacientes com SAS foi de 41,1 anos, com predominância de etnia branca e de sexo feminino. Os pacientes apresentaram prevalência maior de SM (42,9% vs. 13,1%; P < 0,001) e valor maior de resistência insulínica, quando comparados ao grupo controle. Além disso, os pacientes apresentaram maior nível sérico de resistina, em contraste com um menor nível de leptina e similar de adiponectina, quando comparado ao grupo controle. Em uma análise adicional, quando foram comparados os pacientes com SM (N=18) e sem (N=24) SM, os primeiros apresentavam maior idade (48,7 vs. 35,4 anos; P < 0,001), com duração semelhante da doença, status da doença, esquema terapêutico, resistência insulínica e nível sérico de adipocitocinas. Conclusões. Maior frequência de SM e maior valor de resistência insulínica foram observados em pacientes com SAS, com alto nível sérico de resistina e baixo nível de leptina. Além disso, os pacientes de SAS com SM apresentavam idade mais avançada, a exemplo do que ocorrem com outras miopatias inflamatórias idiopáticas com SM / Objectives. A high frequency of metabolic syndrome (MetS) has been recently described in different idiopathic inflammatory myopathies, but not for antisynthetase syndrome (ASS). Therefore, we determined the prevalence of MetS in ASS and the association of MetS with the risk factors of cardiovascular diseases and with ASS-related disease characteristics. Methods. A cross-sectional single center study of 42 consecutive patients with ASS was conducted from 2012 to 2015. For the control group, 84 healthy individuals were matched with patients for gender, age, ethnicity and body mass index-matched, in the same period. All patients had at least four of five items of Bohan and Peter\'s criteria (1975) and also the follow signal and/or symptoms at onset of disease: arthritis, pulmonary involvement, Raynaud\'s phenomenon, fever, \"mechanics\' hands\" and antisynthetase autoantibodies. The disease status was defined, basing on the International Myositis Assessment and Clinical Studies Group (IMACS) questionnaires. Clinical, laboratory and treatment data were collected using a standardized protocol. MetS was defined according to the 2009 Joint Interim Statement. The serum adipocytokine analysis (adiponectin, leptin and resistin) was performed by standardized method, whereas the insulin resistance was performed by Homeostatic Model Assessment (HOMA) method. Results. ASS patients had a median age of 41.1 years and were predominantly female and of white ethnicity. The patients had a higher frequency of MetS (42.9% vs. 13.1%; P < 0.001) and of insulin resistance than controls. Moreover, patients had higher resistin, lower leptin and similar adiponectin levels in serum than controls. Further analysis of the ASS patients with (N=18) and without (N=24) MetS revealed that individuals with the syndrome were older (48.7 vs. 35.4 years; P < 0.001) age at disease onset and had similar disease duration, disease status, treatment, insulin resistance and serum adipocytokine levels. Conclusions. The prevalence of MetS was high in patients with ASS, who also had serum resistin and low leptin levels. Moreover, ASS patients with MetS were older at disease onset, mirroring findings seen in other idiopathic inflammatory myopathies

En vue de contribuer à une meilleure compréhension des atteintes du système musculo-squelettique consécutives à une infection par un arthropod-borne-virus (arbovirus), deux arbovirus ont été étudiés : le virus du chikungunya (CHIKV) et le virus Zika (ZIKV), respectivement de la famille des Togaviridae et des Flaviviridae. Cette étude a été réalisée selon deux axes. Le premier s’intéresse aux atteintes articulaires consécutives à l’infection par le CHIKV. Nous avons mis au point un modèle d’imagerie in vivo reposant sur l’utilisation d’un virus recombinant exprimant la NanoLuciférase. Dans ce modèle, nous démontrons une persistance du signal bioluminescent dans les articulations 34 jours après infection. Par isolement des cartilages articulaires et des cellules constitutives, nous avons pu démontrer que les chondrocytes des cartilages métatarso-phalangiens sont infectés par le CHIKV de manière persistante, suggérant un rôle de réservoir de ces cellules. Les conséquences de l’infection au niveau cellulaire ont ensuite été étudiées in vitro. En utilisant des chondrocytes primaires humains, nous avons confirmé ces observations. De plus, les chondrocytes infectés produisent de nombreuses cytokines, induisant une stimulation du catabolisme du cartilage avec en particulier la synthèse de métalloprotéinases de matrice 3 et 9. De plus, l’infection par le CHIKV provoque la mort des cellules par apoptose, comme démontré par marquage TUNEL et par mesure de l’activité des caspases. Nous avons ensuite étudié les atteintes musculaires et le tropisme cellulaire du ZIKV. Dans un modèle murin, nous avons confirmé la présence de lésions musculaires, et l’utilisation de cellules musculaires primaires humaines a montré la sensibilité des myoblastes à l’infection, les myotubes étant résistants, suggérant un tropisme du ZIKV dépendant de la différenciation cellulaire. Trois souches virales ont été testées, sans relever de différences significatives en termes de cinétique d’infection, de nombre de cellules infectées et de production virale. L’infection des myoblastes entraîne la mort de ces cellules par un mécanisme caspase-indépendant. Des observations en microscopie électronique ont mis en évidence une vacuolisation du cytoplasme suite à l’infection, caractéristique d’une mort cellulaire par paraptose. Une analyse protéomique a démontré que l’infection des myoblastes par une souche asiatique conduit à une modification du protéome s’accentuant entre 24 heures et 48 heures post-infection, avec 225 protéines modulées 24 heures après infection contre 473 après 48 heures, indiquant une activation des voies de synthèse Interferon de type I et l’inhibition des capacités de synthèse des protéines. Ces résultats permettent une meilleure compréhension des atteintes du système-musculo-squelettique par les arbovirus / Musculoskeletal lesions caused by arthropod-borne-viruses (arboviruses) are invalidating for patients and remain poorly understood. In this study, we investigated the development of these manifestations after infection with two arboviruses: chikungunya virus (CHIKV) from the Togaviridae family, and Zika virus (ZIKV) from the Flaviviridae family. The first part of the study focused on arthritis following CHIKV infection. For this purpose, we developed a reporter virus expressing NanoLuciferase and performed experimental infections in a murine model. In vivo, a strong bioluminescent signal indicated viral replication and we observed persistence of the signal in the joints up to 34 days post-infection. By isolating primary murine cells from cartilage, we demonstrated the susceptibility of chondrocytes to CHIKV infection suggesting a role of reservoir of these cells. Furthermore, we investigated the consequences of the infection using in vitro models. We showed that primary human chondrocytes are also susceptible to CHIKV infection, which leads to the production of several cytokines involved in cartilage catabolism and induces apoptosis. In the second part of the study, we studied ZIKV muscular tropism and the associated lesions. Firstly, we confirmed the development of muscular lesions in a mouse model of ZIKA. Then, using human primary muscle cells we observed the infection of myoblasts but not myotubes, suggesting a differentiation-dependent tropism. We compared three viral strains and observed no significant difference in terms of replication, number of infected cells and viral production. Myoblasts infection induced a caspase-independent cells death mechanism and electronic microscope observations revealed intense vacuolization of cytoplasm, suggesting a paraptosis-like cell death. Proteomic analysis revealed that the Asian ZIKV strain modulated protein expression of infected cells with an increased effect after 48 hours. ZIKV-infection induced an important upregulation of biological processes associated with type I interferon and an inhibition of protein synthesis in the infected cells. These results provide valuable information about the mechanisms involved in the development of musculoskeletal lesions during arboviroses

Objetivos: Descrever retrospectivamente uma série de casos de pacientes com miopatia necrosante imunomediada (MNIM), avaliando os efeitos de uma terapia de indução com metilprednisolona (MP) associada ou não à imunoglobulina humana intravenosa (IGIV) sobre a condição muscular tardia, vista por ressonância magnética muscular, e sobre parâmetros de atividade de doença. A seguir, avaliar prospectivamente os efeitos de um programa de treinamento físico combinado assistido nesta amostra sobre a segurança, condição clínica, capacidade aeróbia, força e função muscular. Métodos: Foram inicialmente avaliados em uma análise longitudinal 13 pacientes com MNIM (4 com autoanticorpos anti-hidroxi-metilglutaril coenzima A redutase e 9 com anti-partícula reconhecedora de sinal), no período de 2012 a 2018. Por protocolo institucional, estes pacientes foram tratados ao diagnóstico com um esquema de indução com pulsoterapias de MP associadas ou não à IGIV. Foram analisados os dados clínicos e laboratoriais para cálculo dos critérios de resposta do International Myositis Assessment & Clinical Study Group (IMACS) antes do tratamento e no final do segmento, bem como a ressonância magnética de coxa ao final do segmento, pela qual se quantificaram os níveis de atrofia, edema e lipossubstituição. Adicionalmente, em uma análise quasiexperimental, 8 pacientes da primeira amostra foram também submetidos a um programa de treinamento físico supervisionado combinando exercícios aeróbicos e resistidos, duas vezes por semanas, por 12 semanas. Finalmente, foram comparados, antes e após o programa de treinamento, os dados de: capacidade aeróbia, através do teste cardiopulmonar de esforço; força, através do teste de 1 repetição máxima (RM) no supino e no leg press; e função muscular, através do teste sit-to-stand (STS) e do teste timed up-and-go (TUG). Resultados: Na primeira amostra, composta por 9 mulheres e 4 homens, a idade média dos pacientes ao diagnóstico foi de 53,5 anos e o tempo médio de sintomas até o diagnóstico foi de 4 meses. Todos os pacientes receberam terapia com MP e/ou IGIV. Após uma média de 39 meses de seguimento, todos os parâmetros do IMACS melhoraram de uma forma significativa em relação aos parâmetros basais. Nove pacientes obtiveram resposta clínica completa e, entre eles, dois tiveram remissão completa. Onze pacientes interromperam o uso de glicocorticoides no final desta fase. Apenas 2 pacientes tiveram atrofia muscular ou lipossubstituição classificada como moderada à ressonância magnética, com o restante apresentando achados normais ou leves. Oito pacientes da amostra inicial continuaram o estudo e terminaram o protocolo de treinamento. Nenhuma ativação de doença, agravamento dos escores do IMACS ou eventos adversos foram observados durante todo o período de treinamento. Os pacientes também aumentaram a capacidade aeróbia (tempo para atingir o limiar anaeróbico e tempo para atingir a exaustão), força muscular (1 RM do supino) e função muscular (STS). Conclusão: Nesta série de casos, o tratamento precoce com pulsoterapias de MP e/ou IGIV com o objetivo de resposta clínica completa pode ter sido uma estratégia eficaz de tratamento para a MNIM, atuando sobre os parâmetros de atividade de doença e possivelmente sobre o dano muscular acumulado visto pela ressonância magnética. Ademais, o treinamento físico combinado supervisionado em pacientes MNIM se mostrou seguro e eficaz, promovendo aumento de capacidade aeróbia, força e função muscular / Objectives: To describe retrospectively a case series of patients with immunemediated necrotizing myopathy (IMNM), evaluating the effects of an induction therapy with methylprednisolone (MP) associated or not with intravenous human immunoglobulin (IVIG) on late muscle condition, as seen by muscle magnetic resonance imaging, and on parameters of disease activity. Next, to evaluate prospectively the effects of an assisted and combined physical training program in this sample regarding safety, clinical status, aerobic capacity, muscle strength and function. Methods: Thirteen patients with IMNM (4 patients with anti-hydroxymethyl- glutaryl coenzyme A reductase autoantibodies and 9 patients with antisignal- recognition particle) were initially evaluated in a longitudinal analysis, from 2012 to 2018. By institutional protocol, these patients were treated at diagnosis with an induction scheme with MP pulse therapies associated or not with IVIG. The clinical and laboratory data to calculate the response criteria of the International Myositis Assessment & Clinical Study Group (IMACS) before treatment and at the end of the segment, as well as the magnetic resonance imaging of the thigh at the end of the segment, in order to assess atrophy, edema and fat replacement, were quantified. Additionally, in a quasi-experimental analysis, eight patients of the first sample were also submitted to a supervised physical training program combining aerobic and resisted exercises, twice a week, for 12 weeks. Finally, before and after the training program, the following data were compared: aerobic capacity, through cardiopulmonary exercise test; strength, through the maximal repetition test (RM) in the bench press and in the leg press; and muscular function, through the sit-tostand test (STS) and the timed up-and-go (TUG) test. Results: In the first sample, composed of 9 women and 4 men, the mean age of the patients at diagnosis was 53.5 years and the mean duration of symptoms until the diagnosis was 4 months. All patients received MP and/or IVIG therapy. After an average of 39 months of follow-up, all IMACS parameters improved significantly over baseline parameters. Nine patients had complete clinical response and, among them, two had complete remission. Eleven patients discontinued the use of glucocorticoids at the end of this phase. Only 2 patients had muscle atrophy or fat replacement classified as moderate in magnetic resonance, with the remainder presenting normal or mild findings. Eight patients in the initial sample continued the study and completed the training protocol. No disease activation, worsening of IMACS scores or adverse events were observed throughout the training period. Patients also increased aerobic capacity (time to reach the anaerobic threshold and time to achieve exhaustion), muscle strength (1 RM of the bench press) and muscle function (STS). Conclusion: In this case series, early treatment with MP and/or IVIG pulse therapy with the objective of complete clinical response may have been an effective treatment strategy for IMNM, acting on the parameters of disease activity and possibly on the accumulated muscle damage seen by magnetic resonance imaging. In addition, the supervised combined physical training in IMNM patients was shown to be safe and effective, increasing aerobic capacity, strength and muscle function

Les maladies auto-immunes et systémiques sont des maladies sur lequel le champ de la recherche pose son œil de façon appuyée depuis 15 ans, du fait de l’émergence de thérapies biologiques ciblées. Ces pathologies sont volontiers hétérogènes, au mieux de fréquence ou caractéristiques particulières dans les populations d’origine Africaine. La connaissance de l’épidémiologie, et des caractéristiques de ces maladies est un préalable essentiel à la mise en place de recherche plus fondamentale pour aider à décomposer leurs physiopathologies souvent extrêmement complexes. En effet, la comparaison de différences marquées entre deux expressions dans des populations différentes d’une même maladie peut permettre d’aider à en dénouer le fil. Nous proposons dans ce travail une estimation des caractéristiques du lupus cutané et du lupus systémique en Guyane Française qui retrouve une faible fréquence de la maladie, la plus faible jamais retrouvée dans une population subsaharienne. Nous décrivons en Martinique sur le plan épidémiologique comme clinique une forme rare de myosite appelée syndrome des anti-synthétases semblant très particulière, l’épidémiologie et la description de la maladie de Kikuchi-Fujimoto pour la première fois dans la littérature, l’épidémiologie et les caractéristiques à base de population de la maladie de Behcet, des principales vascularites (périartérite noueuse, micropolyangéite, granulomatose éosinophile avec polyangéite, granulomatose avec polyangéite), de l’hypertension pulmonaire des connectivites qui semblent plus fréquentes que chez les Européens. Les néphropathies du lupus systémiques sont décrites dans la population Guadeloupéenne montrant une grande fréquence des néphropathies prolifératives. Le protocole EUROLUPUS qui permet le traitement de ces néphropathies prolifératives du lupus systémique avec de faibles doses de cyclophosphamide et de corticoïdes, est évalué en Martinique sur 30 patients alors qu’il ne l’a jamais été dans une population d’origine Africaine. Il semble y être aussi efficace que chez les patients d’origine Européenne, alors que les néphropathies y ont un pronostic meilleur. La maladie de Sjögren primaire est décrite en Martinique très proche de ce qu’on trouve en Europe sur le plan du tableau clinique et évolutif alors que cela n’est l’objet d’aucune étude dans une population d’origine noire Africaine. Nous avons par ailleurs montré en Martinique l’amélioration de la prise en charge du lupus systémique en Martinique au travers de la régression au fil du temps d’une des complications de la corticothérapie les plus pénibles pour les patients, l’ostéonécrose aseptique. La sclérodermie systémique est décrite à base de population avec épidémiologie dans les deux départements de Guadeloupe et Martinique, montrant des caractéristiques proches de celles retrouvées chez les AfroAméricains. Nous avons aussi montré la fréquence et la gravité des atteintes ORL des myopathies inflammatoires sur ces 2 départements avec une fréquence inhabituelle de certaines maladies auto-immunes dont le lupus systémique et les myosites inflammatoires associées aux anticorps anti-SRP, et l’absence de myosite à inclusion. Au total, nous apportons une somme de connaissance descriptive de ces maladies auto-immunes et systémiques permettant la mise en place de recherches plus fondamentales avec des bases solides par rapport aux profils hétérogènes de ces maladies. / Auto-immunes and systemic diseases are priorities for researchers since 15 years. This is related to the emergence of biological therapies, associated to great efficacy. Although, these diseases are heterogeneous, depending of different parameters such as ethnicity or geography. In the African descent population, we encounter unusual or particular manifestations of these diseases. Also, the knowledge of epidemiology and population based descriptions are crucial to properly initiate works on these populations, but also to understand a particularly complex physiopathology by using differences between populations. We describe in this work the population based characteristics of pure cutaneous lupus and systemic lupus, including an epidemiology of the incidence of the lowest incidence ever found in a population of African heritage. We also describe a population based series of anti-synthetase syndrome, confirming that the presentation is totally different compared to caucasians, and allows in Martinique the incidence, never explored before. We also provide the first evaluation of Kikuchi-Fujimoto disease in a population of African origin, and the first incidence ever realized. We do the same evaluation of the epidemiology of Behcet’s disease in a black origin population that shows that this disease was at a similar frequency in Martinique and in Europe. Micropolyangeitis, polyarteritis, eosinophilic granulomatosis with polyangeitis and Granulomatosis with polyangeitis were evaluated in an epidemiologic study in Martinique, with addition of some cases from other French American region for a more powerful characteristics description. These diseases seem less frequent than in Europe, associated with less severity except for micropolyangeitis. EUROLUPUS, a protocol with low dose IV cyclophosphamide and low dose steroids, used to treat proliferative nephritis of systemic lupus is shown to have the same efficacy in Martinique than in patients of European origin. Primary Sjögren syndrome, evaluated in Martinique, is very similar in expression than what is found in Europe. The decrease overtime of aseptic osteonecrosis, a steroid side effect, is a witness of better control of systemic lupus activity with less usage permitted by protocols and new immunosuppressive drugs such as mycophenolate. Systemic sclerosis is described as very close to African American in a population based study in Martinique and Guadeloupe. We finally show that the rare ENT involvement of idiopathic inflammatory myositis is frequent in our population, associated with poor outcome, and surprisingly frequently related to systemic lupus and necrotizing myositis associated to SRP antibody but not to inclusion body myositis. To conclude, we allow an amount of description of these diseases in our region, including pioneer studies. This works tends to be the basis for studies to be continued in a more fundamental way in our countries.

Myofibrillogenesis is a complex process, which involves assembly of hundreds of structural proteins in a highly ordered manner to form the contractile structural unit of muscle, the sarcomere. Several myopathic conditions reported in humans are caused due to abnormal myofibrillogenesis owing to mutations in the genes coding for many of these structural proteins. These myopathies have highly variable clinical features and time of onset. Since their aetiology is poorly understood, it becomes imperative to have a model system to study the muscle defects. Present study proposes to employ the Indirect Flight Muscle (IFM) system in Drosophila melanogaster as a model to analyse the development/onset of some of these myopathies and resulting pathophysiology. We have carried out a systematic study on mutations in two major proteins of the sarcomere, actin and myosin, to understand the pathophysiology associated with the disease conditions and in turn gain insights into the process of myofibrillogenesis. To verify whether the human muscle phenotypes are observed in flies, we analysed the IFM for functional and structural defects categorised by the presence of aberrant sarcomeric structures. An important question that we have addressed is whether mutants of the Drosophila IFM recapitulate human conditions and whether it can serve as a good genetic model to study the developmental mechanisms of the human skeletal myopathies in vivo. Mutations of the human ACTA1 skeletal actin gene produce seven congenital myopathies – actin myopathy, nemaline rod myopathy, intranuclear rod myopathy, congenital fibre type disproportion, congenital myopathy with core-like areas, cap disease and zebra body myopathy. Four known mutations in Act88F—a Drosophila homologue of ACTA1—occur at the same actin residues mutated in ten ACTA1 nemaline mutations, A138D/P, R256H/L, G268C/D/R/S and R372C/S. These Act88F mutants were examined for muscle phenotypes with nemaline structures. Mutant homozygotes show phenotypes ranging from lack of myofibrils to almost normal sarcomeres at eclosion. Whereas, heterozygotes do allow myofibrillar assembly to certain extent; however, atypical structures are seen adjacent to normal sarcomeres. Aberrant Z disc-like structures and serial Z disc arrays, ‘zebra bodies’, are observed in homozygotes and heterozygotes of all the four Act88F mutants. The electron-dense structures observed in electron micrographs show homologies to human nemaline bodies/rods, but are much smaller than those typically found in the human myopathy. A possible mechanism for the ‘zebra bodies’ is proposed based on this study. Analysis of IFM at early developmental stages shows that in three of the mutants, there is an abnormal myofibril assembly leading to malformed sarcomeres mirrored in the adult stages. In one of the Act88F mutants, normal myofibrils are seen post-eclosion but the IFM show activity dependant progression of muscle degeneration. All the Act88F mutants produce dominant disruption of muscle structure and function which cannot be rescued even by three copies of the wild type Act88F gene implying that the mutants are strong antimorphs. Myosin myopathies are a group of human muscle diseases with heterogeneous clinical features and are caused by mutations in the skeletal muscle myosin heavy chain. We identified two chemical mutagen generated flightless mutants, Ifm(2)RU1 and ifm(2)RU2 that map closely to myosin heavy chain gene (Mhc) region. Since there are no structural proteins predicted in the mapped region, it was likely that these two are Mhc mutations. We show that Ifm(2)RU1 and ifm(2)RU2 are indeed Mhc mutations and the molecular aberrations affect amino acid residues present in the myosin rod region. Human muscle myosin heavy chain (MyHC) mutations that cause Laing early onset distal myopathy and myosin storage myopathy occur in this domain of the protein. Even though mutations lie in the same region of myosin rod, Ifm(2)RU1 is semidominant, whereas ifm(2)RU2 is recessive. Both the mutants show IFM defects and the presence of abnormal myofibrils. Mutant myofibrillar structures can be rescued with an additional wild type Mhc gene copy. However, the restored myofibrillar structure is incapable of rescuing the flight ability of mutants. The muscle phenotypes are due to defects in thick filament assembly which manifest from the early stages of sarcomere development. The MHC protein rod region is an α-helix that forms coiled-coils which further self assemble to form thick filaments or aggregates as observed in in vitro conditions. Biophysical and biochemical analyses reveal that the coiled-coil structure of mutant rods is not affected, however the thermodynamic stability is altered in ifm(2)RU2 mutation. Interestingly, rod aggregate size and stability are not affected in mutant rods. The Drosophila MHC mutant rods were studied along with four MHC mutant rods that harbour human rod mutations to compare the molecular consequences. The Drosophila mutations do not hamper the rod structure and assembly. Therefore, the defects may arise due to altered interactions with myosin rod binding proteins. Flightin is an extensively studied myosin rod binding protein. The amount and phosphorylation status of flightin are an extremely sensitive measure of thick filament assembly. Flightin phosphorylation is affected in the mutants suggesting a functional dependence on MHC and it also indicates MHC instability. In the light of the work done, we have assessed the mutations with respect to their structure-functional implications. The acto-myosin interactions responsible for the defects are also discussed. Formation of unusual myofibrillar structures are analysed with regards to the process of myofibrillogenesis. An understanding of this entire process with the information available from IFM is reviewed in detail. The work so far has helped in understanding the manifestation of myopathies at tissue/cellular levels with insights into the plausible mechanisms of origin of the disease phenotypes. Myopathic condition may arise due to developmental or functional defects. For therapeutic considerations, the fly provides a simple test to inspect the effects of adding extra copies of the wild type gene. We conclude that the Drosophila IFM provide a good model system for the study of human ACTA1 and MyHC myopathies.

Introdução: As estatinas são drogas amplamente utilizadas na prevenção primária e secundária de doenças cardiovasculares, por reduzirem o nível de colesterol. Porém alguns pacientes podem apresentar elevação da creatinofosfoquinase (CPK) e sintomas musculares relacionados ao seu uso. Além da CPK, outros marcadores de dano muscular podem apresentar alterações. Este estudo analisou a concentração dos marcadores bioquímicos, CKMB e anidrase carbônica III (CAIII) e sua relação com a presença de miosite. Métodos: Foram selecionados pacientes em tratamento com estatinas e com elevação da CPK. Foram realizadas as determinações de CKMB e CAIII e analisadas as variáveis clínicas e laboratoriais destes pacientes. Resultados: Cerca de 10% dos pacientes em tratamento com estatina apresentaram elevações de CPK acima 1x o limite superior de normalidade (LSN). Desses, 50,4% apresentaram sintomas musculares, definido como miosite. O uso de sinvastatina [OR=2,24 (IC95%:1,47-3,42)], o índice de massa corpórea > 28 Kg/m2 [OR=1,06 (IC95%: 1,01-1,10)] e a CKMB > 1xLSN [OR=1,59 (IC95%: 1,02-2,49)] apresentaram-se como preditores independentes para a ocorrência de miosite. A CKMB aumentada foi observada em 36,2% dos pacientes (7,17±4,4 ng/mL). Os pacientes com e sem miosite apresentaram valores semelhantes de CAIII (211,3±93,4pg/mL vs 204,0±84,6pg/mL; p=0,549). Pacientes diabéticos apresentaram elevações significantes de CKMB em relação aos não diabéticos (4,8±4,6ng/mL vs 3,5±2,4ng/mL; p=0,0006) e não apresentaram diferenças quanto à presença de miosite. Conclusão: A CKMB apresentou alteração em parte dos pacientes tratados com estatinas e foi um preditor independente para a presença de miosite. A CAIII não foi considerada um bom marcador de dano muscular na população deste estudo / Introduction: Statins are drugs widely used in primary and secondary prevention of cardiovascular diseases, due to the decreasing effect on cholesterol level. However, some patients may present elevated levels of creatine phosphokinase (CK) and muscle symptoms related to statin use. In addition to CK, other markers of muscle damage may present changes. This study analyzed the concentration of biochemical markers, CKMB and carbonic anhydrase III (CAIII) and related them to the presence of myositis. Methods: Patients on statin therapy and CK elevation were selected. CKMB and (CAIII) assays were performed and the clinical and laboratory variables of these patients were analyzed. Results: About 10% of the patients receiving statin therapy (6692) presented CK elevations above 1x upper reference limit (URL). Muscular symptoms, defined as myositis, were presented in 50.4% of these patients. Use of simvastatin [OR=2,24 (IC95%:1,47-3,42)], a body mass index > 28 kg / m2 [OR = 1.06 (95% CI: 1.01-1, 10)] and a concentration of CKMB > 1x URL [OR = 1.59 (95% CI: 1.02-2.49)] presented as independent predictors for the occurrence of myositis. Increased CKMB was observed in 36.2% of patients (7.17 ± 4.4 ng / mL). Patients with and without myositis had similar CAIII values (211.3 ± 93.4pg / mL vs 204.0 ± 84.6pg / mL, p = 0.549). Diabetic patients showed significant elevations of CKMB compared to non-diabetic patients (4.8 ± 4.6 ng / mL vs. 3.5 ± 2.4 ng / mL, p = 0.0006) and did not present differences regarding the presence of myositis. Conclusion: CKMB level changed in part of the patients treated with statins and this enzyme was an independent predictor for the presence of myositis. CAIII was not considered a good marker of muscle damage in the studied population

Les myosites sont des maladies auto-immunes, caractérisées par des atteintes musculaires et extra musculaires. Le diagnostic des myosites peut être difficile et nécessite de l’expertise, afin d’éviter l’administration de thérapie inapproprié. Les mécanismes impliqués au cours des myosites sont peu connus. Notre but était de décrire le profil immunitaire des patients, afin d’identifier des biomarqueurs. Nous avons utilisé un panel de 36 marqueurs pour caractériser les PBMC issus de patients actifs (MIs, SAS anti-Jo1, myopathies anti-SRP et anti-HMGCR) et de sujets sains par cytométrie de masse combiné au « barcoding ». Tout d’abord, nous avons mis au point une procédure technique pour la détection simultanée de cibles extracellulaires et intracellulaires. En utilisant différents outils bio-informatiques, nous avons isolé une fréquence de lymphocytes CD8+T-bet+ > 51.5% comme étant un biomarqueur spécifique de la MIs en comparaison aux autres myosites, avec une sensibilité de 94,74% et une spécificité de 88,46%. De plus, nous avons identifié un profil immunitaire CD8+T-bet+ CD57- activé, potentiellement capable de prolifération et de maintien de mécanismes auto-immuns chez les patients atteints de MIs. Chez les patients anti-Jo1, nous avons observé une dérégulation de l’homéostasie des lymphocytes B, caractérisée par une diminution des lymphocytes B mémoires circulants. La présence de ces derniers dans le muscle des patients suggère qu’ils se nichent dans le muscle afin d’éviter l’action des immunosuppresseurs. Ces travaux ont permis l’identification de biomarqueurs et de phénotypes cellulaires potentiellement impliqués au cours de la MIs et du SAS anti-Jo1. / Myositis is an autoimmune disease characterized by muscular and extra-muscular disorders. In the early stages of the disease, the diagnosis of myositis can be misleading and requires expertise, in order to avoid the administration of inappropriate treatment. The mechanisms involved in these diseases are poorly understood. Our aim was to describe the immune profile specific to each patient group, in order to identify biomarkers that may be useful for diagnosis and management of patients. We used a panel of 36 markers by mass cytometry to characterize PBMCs derived from active patients (sIBM, anti-Jo1 ASyS, anti-SRP and anti-HMGCR myopathies) and healthy subjects. First, we developed and optimized a technical procedure for the simultaneous detection of extracellular and intracellular targets by mass cytometry. Using different bioinformatics tools, we isolated a frequency of CD8 +T-bet + cells > 51.5% as a specific biomarker for sIBM compared to other myositis, with a sensitivity of 94.74% and a specificity of 88. , 46%. In addition, we identified an activated CD8 + T-bet + CD57- immune profile, potentially capable of proliferation and the maintenance of autoimmune mechanisms in patients with sIBM. In anti-Jo1 patients, we observed a dysregulation of B cell homeostasis, characterized by a decrease in circulating memory B cells. The presence of the latter in the muscle of patients suggests that they nest in the muscle to avoid immunosuppressants. This work allowed the identification of a biomarker that could enhance the diagnosis of MIs compared to other myositis and the identification of cells potentially involved during sIBM and anti-Jo1 ASyS.

Patients with connective tissue diseases (CTD) such as systemic lupus erythematosus (SLE) have an increased risk for infections. This study investigated the outcome and characteristics of CTD patients under intensive care unit (ICU) treatment for sepsis

No description available.