Impact of experimental obesity on diaphragm structure, function, and bioenergetics.

Obesity is associated with bioenergetic dysfunction of peripheral muscles; however, little is known regarding the impact of obesity on the diaphragm. We hypothesized that obesity would be associated with diaphragm dysfunction attributable to mitochondrial oxygen consumption and structural and ultrastructural changes. Wistar rat litters were culled to 3 pups to induce early postnatal overfeeding and consequent obesity. Control animals were obtained from unculled litters. From postnatal day 150, diaphragm ultrasound, computed tomography, high-resolution respirometry, immunohistochemical, biomolecular, and ultrastructural histological analyses were performed. The diaphragms of obese animals, compared with those of controls, presented changes in morphology as increased thickening fraction, diaphragm excursion, and diaphragm dome height, as well as increased mitochondrial respiratory capacity coupled to ATP synthesis and maximal respiratory capacity. Fatty acid synthase gene expression was also higher in obese animals, suggesting a source of energy for the respiratory chain. Myosin heavy chain-IIA was increased, indicating shift from glycolytic toward oxidative muscle fiber profile. Diaphragm tissue also exhibited ultrastructural changes, such as compact, round, and swollen mitochondria with fainter cristae and more lysosomal bodies. Dynamin-1 expression in the diaphragm was reduced in obese rats, suggesting decreased mitochondrial fission. Furthermore, gene expressions of peroxisome γ proliferator-activated receptor coactivator-1α and superoxide dismutase-2 were lower in obese animals than in controls, which may indicate a predisposition to oxidative injury. In conclusion, in the obesity model used herein, muscle fiber phenotype was altered in a manner likely associated with increased mitochondrial respiratory capability, suggesting respiratory adaptation to increased metabolic demand.NEW & NOTEWORTHY Obesity has been associated with peripheral muscle dysfunction; however, little is known about its impact on the diaphragm. In the current study, we found high oxygen consumption in diaphragm tissue and changes in muscle fiber phenotypes toward a more oxidative profile in experimental obesity.

A intervenção precoce do paciente com síndrome coronariana aguda e sua implicação na redução da morbimortalidade cardiovascular / The early intervention of acute coronary disease and its implication in the reduction of cardiovascular morbimortality

Introdução. O infarto agudo do miocárdio apresenta significativas taxas de morbimortalidade. A reperfusão precoce por angioplastia primária é a intervenção que reduz a mortalidade e as complicações, e deve ser iniciada em até 12 horas, a fim de impedir a perda muscular irreversível. O tempo entre chegada do paciente ao hospital e a abertura da artéria acometida, tempo porta-balão, determina a morbimortalidade do paciente. Objetivo. Esse estudo busca analisar o potencial benefício do tratamento da reperfusão coronariana precoce, os fatores de risco, as possíveis complicações e o Killip em pacientes que sofreram infarto agudo do miocárdio relacionando-os a sua morbimortalidade. Materiais e métodos. Estudo observacional transversal realizado por meio de coleta de dados dos prontuários dos pacientes submetidos a angioplastia primária de um hospital privado. Resultados. A hipertensão arterial sistêmica foi a variável mais prevalente (75%), e que houve predomínio no sexo masculino (71%) e associação com a progressão da idade. 61% dos pacientes apresentaram um tempo porta balão menor que 90 minutos. Houve significância estatística entre o tempo porta balão e a evolução do Killip, evidenciando um tempo porta-balão maior que 90 minutos na maioria dos pacientes que obtiveram aumento da pontuação do Killip. Conclusão. A precocidade da intervenção no paciente com IAM impacta na morbimortalidade, visto que o tempo porta balão está diretamente associado a evolução da do Killip. Logo, deve-se identificar os fatores que interferem no atendimento, a fim de proporcionar uma intervenção otimizada. (AU)

Introduction. Acute myocardial infarction has significant rates of morbidity and mortality. Early reperfusion by primary angioplasty is the intervention that reduces mortality and complications, and should be started within 12 hours in order to prevent irreversible muscle loss. The time between the patient's arrival at the hospital and the opening of the affected artery, door-to-balloon time, determines the patient's morbidity and mortality. Objective. The proposition of this study is to analyze the potential benefits of early coronary reperfusion, associated with the risk factors, possible complications, and the Killip score in patients whit acute myocardial infarction (AMI) and the relation of those factors with the morbidity and mortality. Materials and methods. This is a transversal observational study and uses data collected of medical records of patients subjected to primary angioplasty in a private hospital. Results. Systemic arterial hypertension was the most prevalent one (75%), it was more common in males (71%) and associated with a higher age. In 61% of the patients port-balloon time was less than 90 minutes. There was statistical significance between port-balloon time and Killip score evaluation, that showed a higher score in patient with a port-balloon time that exceeded 90 minutes. Conclusion. Early intervention in patients with AMI impacts morbimortality, once that the port-balloon time is directly associated with the Killip score results. Therefore, all factors that can lead to a delay in their care of those patients should be identified with the objective of optimize the intervention. (AU)