LEONARDO AUGUSTO MIANA
Projetos de Pesquisa
Unidades Organizacionais
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina - Médico
2 resultados
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- Reversible pulmonary trunk banding. IX. G6PD activity of adult goat myocardium submitted to ventricular retraining(2013) ASSAD, Renato Samy; MIANA, Leonardo Augusto; FONSECA-ALANIZ, Miriam Helena; ABDUCH, Maria Cristina Donadio; SILVA, Gustavo Jose Justo da; OLIVEIRA, Fernanda Santos de; MOREIRA, Luiz Felipe Pinho; KRIEGER, Jose EduardoObjective: Increased glucose 6-phosphate dehydrogenase activity has been demonstrated in heart failure. This study sought to assess myocardial glucose 6-phosphate dehydrogenase activity in retraining of the subpulmonary ventricle of adult goats. Methods: Eighteen adult goats were divided into three groups: traditional (fixed banding), sham, and intermittent (adjustable banding, daily 12-hour systolic overload). Systolic overload (70% of systemic pressure) was maintained during a 4-week period. Right ventricle, pulmonary artery and aortic pressures were measured throughout the study. All animals were submitted to echocardiographic and hemodynamic evaluations throughout the protocol. After the study period, the animals were killed for morphological and glucose 6-phosphate dehydrogenase activity assessment. Results: A 55.7% and 36.7% increase occurred in the intermittent and traditional right ventricle masses, respectively, when compared with the sham group (P<0.05), despite less exposure of intermittent group to systolic overload. No significant changes were observed in myocardial water content in the 3 groups (P=0.27). A 37.2% increase was found in right ventricle wall thickness of intermittent group, compared to sham and traditional groups (P<0.05). Right ventricle glucose 6-phosphate dehydrogenase activity was elevated in the traditional group, when compared to sham and intermittent groups (P=0.05). Conclusion: Both study groups have developed similar right ventricle hypertrophy, regardless less systolic overload exposure of intermittent group. Traditional systolic overload for adult subpulmonary ventricle retraining causes upregulation of myocardial glucose 6-phosphate dehydrogenase activity. It may suggest that the undesirable ""pathologic systolic overload"" is influenced by activation of penthose pathway and cytosolic Nicotinamide adenine dinucleotide phosphate availability. This altered energy substrate metabolism can elevate levels of free radicals by Nicotinamide adenine dinucleotide phosphate oxidase, an important mechanism in the pathophysiology of heart failure.
- Reversible Pulmonary Trunk Banding VIII: Intermittent Overload Causes Harmless Hypertrophy in Adult Goat(2013) MIANA, Leonardo A.; ASSAD, Renato S.; ABDUCH, Maria C. D.; SILVA, Gustavo J. J.; NOGUEIRA, Ananda R.; AIELLO, Vera D.; MOREIRA, Luiz Felipe P.Background. Traditional pulmonary artery banding (PAB) is not always suitable for mature subpulmonary ventricle retraining. We sought to assess in detail the myocardial morphologic adaptations of two different protocols for inducing right ventricular (RV) hypertrophy in an adult animal model. Methods. Eighteen adult goats were distributed into three groups: sham (no systolic overload), traditional (continuous systolic overload), and intermittent (daily 12-hour systolic overload). Systolic overload was adjusted to achieve a 0.7 RV-to-aortic pressure ratio. All animals underwent weekly echocardiographic studies, and hemodynamic evaluations were performed 3 times a week. After 4 weeks, the animals were humanely killed for morphologic assessment. Results. A 37.2% increase was observed in the RV wall thickness of the intermittent group (p < 0.05), but no significant echocardiographic changes were observed in the other two groups. The intermittent and traditional groups had a 55.7% and 36.7% increase in RV mass, respectively, compared with the sham group (p < 0.05). No differences were observed in myocardial water content of the three groups (p = 0.27). RV myocardial fiber and nuclei diameters were increased in the intermittent group compared with the sham group (p < 0.05). The area of collagen deposition in the RV interstitium was increased 98% in traditional group compared with the sham group (p < 0.05). No significant cellular proliferation occurred in any group. Conclusions. This study suggests that a more effective and harmless hypertrophy can be achieved in adult animals using intermittent PAB compared with the traditional approach. (Ann Thorac Surg 2013;95:1422-8) (c) 2013 by The Society of Thoracic Surgeons