Exercise training prevents skeletal muscle damage in an experimental sepsis model

OBJECTIVE: Oxidative stress plays an important role in skeletal muscle damage in sepsis. Aerobic exercise can decrease oxidative stress and enhance antioxidant defenses. Therefore, it was hypothesized that aerobic exercise training before a sepsis stimulus could attenuate skeletal muscle damage by modulating oxidative stress. Thus, the aim of this study was to evaluate the effects of aerobic physical preconditioning on the different mechanisms that are involved in sepsis-induced myopathy. METHODS: Male Wistar rats were randomly assigned to either the untrained or trained group. The exercise training protocol consisted of an eight-week treadmill program. After the training protocol, the animals from both groups were randomly assigned to either a sham group or a cecal ligation and perforation surgery group. Thus, the groups were as follows: sham, cecal ligation and perforation, sham trained, and cecal ligation and perforation trained. Five days after surgery, the animals were euthanized and their soleus and plantaris muscles were harvested. Fiber cross-sectional area, creatine kinase, thiobarbituric acid reactive species, carbonyl, catalase and superoxide dismutase activities were measured. RESULTS: The fiber cross-sectional area was smaller, and the creatine kinase, thiobarbituric acid reactive species and carbonyl levels were higher in both muscles in the cecal ligation and perforation group than in the sham and cecal ligation and perforation trained groups. The muscle superoxide dismutase activity was higher in the cecal ligation and perforation trained group than in the sham and cecal ligation and perforation groups. The muscle catalase activity was lower in the cecal ligation and perforation group than in the sham group. CONCLUSION: In summary, aerobic physical preconditioning prevents atrophy, lipid peroxidation and protein oxidation and improves superoxide dismutase activity in the skeletal muscles of septic rats.

Miocardiopatía hipertrófica neonatal: una forma de presentación clínica de la enfermedad de Pompe / Neonatal hypertrophic cardiomyopathy: a clinical presentation form of Pompe´s disease

La enfermedad de Pompe es una miopatía metabólica pordéficit de la enzima alfa-glucosidasa ácida lisosómica. Los pacientes afectados presentan hipotonía, alteración de la succión, falta de progreso, imposibilidad de adquirir pautas madurativas y miocardiopatía hipertrófica con insuficiencia cardíaca y muerte en el primer año. La manifestación más prominente es la cardíaca, el diagnóstico puede realizarse precozmente por la hipertrofia miocárdica. El diagnóstico tempranocobra mayor importancia a partir del desarrollo de una enzima recombinante humana (rhAGLU). Los pacientes tratados han demostrado mayor supervivencia y adquisición de pautas madurativas.Presentamos el caso de un recién nacido con miocardiopatíahipertrófica en quien se diagnosticó enfermedad de Pompe. A partir del paciente, se diagnosticó a su padre con la forma del adulto de la enfermedad, situación pocas veces descripta. Con el desarrollo de rhAGLU comenzó una nueva era en la historia de la enfermedad y nuestro paciente ya se encuentra en tratamiento

Desmin: molecular interactions and putative functions of the muscle intermediate filament protein

Desmin is the intermediate filament (IF) protein occurring exclusively in muscle and endothelial cells. There are other IF proteins in muscle such as nestin, peripherin, and vimentin, besides the ubiquitous lamins, but they are not unique to muscle. Desmin was purified in 1977, the desmin gene was characterized in 1989, and knock-out animals were generated in 1996. Several isoforms have been described. Desmin IFs are present throughout smooth, cardiac and skeletal muscle cells, but can be more concentrated in some particular structures, such as dense bodies, around the nuclei, around the Z-line or in costameres. Desmin is up-regulated in muscle-derived cellular adaptations, including conductive fibers in the heart, electric organs, some myopathies, and experimental treatments with drugs that induce muscle degeneration, like phorbol esters. Many molecules have been reported to associate with desmin, such as other IF proteins (including members of the membrane dystroglycan complex), nebulin, the actin and tubulin binding protein plectin, the molecular motor dynein, the gene regulatory protein MyoD, DNA, the chaperone alphaB-crystallin, and proteases such as calpain and caspase. Desmin has an important medical role, since it is used as a marker of tumors' origin. More recently, several myopathies have been described, with accumulation of desmin deposits. Yet, after almost 30 years since its identification, the function of desmin is still unclear. Suggested functions include myofibrillogenesis, mechanical support for the muscle, mitochondrial localization, gene expression regulation, and intracellular signaling. This review focuses on the biochemical interactions of desmin, with a discussion of its putative functions.

Dor e fadiga muscular / Pain and muscle fatigue

Vem sendo bastante freqüente a procura de clínicas especializadas por pacientes com queixa de dor e(ou) fadiga muscular. Esses sintomas sao as duas maneiras pelas quais os músculos respondem a um stress metabólico, seja por trabalho excessivo, seja por incapacidade de produzir a energia necessária para realizar esforços mesmo leves. Na fibromialgia, síndrome miofascial, polimialgia reumática, síndrome de fasciculaçao e câimbra, síndrome do homem rígido e doença de Brody nao há fraqueza objetiva provocada por exercícios e o CPK é normal. Nas síndromes miálgica com internalizaçao de capilares e miálgica com eosinofilia, na fadiga crônica e nas doenças devidas a déficit na produçao de energia muscular econtramos fraqueza muscular induzida por exercícios, além de biópsia muscular alterada e(ou) CPK elevado. Sao feitas referências a cada uma das afecçoes acima relatadas, especialmente àquelas secundárias a alteraçoes do metabolismo das vias produtoras de energia muscular (ATP), quer sejam do metabolismo dos hidratos de carbono, quer da oxidaçao dos ácidos graxos, quer da reaçao desaminase. Sao feitas consideraçoes sobre diagnóstico clínico e provas laboratoriais, com particular ênfase sobre as dosagens do ácido láctico com ou sem isquemia, quociente respiratório e biópsia muscular. Sao feitas ainda referências com relaçao à terapêutica.

Miopatia mitocondrial: relato de 12 casos com estudo histoquímico do músculo esquelético / Mitochondrial myopathy: report of 12 cases with histochemical study of the skeletal muscle

Säo relatados 12 pacientes com o diagnóstico de MM definidos histoquimicamente. Nove pacientes eram do sexo masculino e tres do sexo feminino. A idade de início dos sintomas variou desde o período neonatal até os 35 anos de idade (mediana 14 anos). Foram identificadas como características principais a fraqueza muscular, oftalmoplegia e ptose palpebral em 10 pacientes. Um paciente apresentou quadro de intolerância aos exercícios e outro além da fraqueza muscular, alteraçäo do comportamento. Säo discutidos aspectos clínicos e o diagnóstico diferencial de nossos pacientes