Browsing by Author "Mellado R."

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    Determinaciones de niveles de creatina y lípidos mediante espectroscopia por resonancia magnética en miocardio de pacientes con insuficiencia cardiaca no isquémica
    (Sociedad Medica de Santiago, 2010) Winter J.L.; Castro P.; Chalhub M.; Verdejo H.; Greig D.; Gabrielli L.; Hernández C.; Uribe S.; Meneses L.; Chiong M.; Lavandero S.; Concepción R.; Mellado R.
    Background: Heart failure (HF) is characterized, among other features, by the development of alterations in myocardial energy metabolism, involving a decrease in glucose utilization and increased free fatty acid uptake by cardiomyocytes, associated with decreased deposits of high-energy phosphates (creatine phosphate/ creatine transporter). Magnetic resonance (MR) imaging allows a direct and noninvasive assessment of myocardial metabolites. Aim: To measure myocardial creatine and lipids by MR spectroscopy among patients with HF. Material and Methods: Cardiac MR spectroscopy (1.5 Tesla) with Hydrogen antenna and single voxel acquisition was performed in five patients with non-ischemic heart failure, aged 58 ± 9.7 years, (60% males) and 5 healthy volunteers matched for age and sex. We analyzed the signals of creatine (Cr), lipids (L) and water (W) in the interventricular septum, establishing the water/lipid (W/L) and water/creatine (W/Cr) index to normalize the values obtained. Results: Among patients, left ventricular ejection fraction was 32 ± 6.9%, 60% were in functional capacity II, 60% had hypertension and one was diabetic. Spectroscopic curves showed a depletion of total Cr, evidenced by the W/ Cr index, among patients with heart failure, when compared with healthy controls (1.46 ± 1.21 and 5.96 ± 2.25 respectively, p < 0,05). Differences in myocardial lipid content, measured as the W/L index, were not significant (5.06 ± 2.66 and 1.80 ± 1.62 respectively, p = 0.08). Conclusions: Among patients with heart failure of non-ischemic etiology, there is a depletion of creatine levels measured by MR spectroscopy.
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    Oxidative stress and inflammation in heart failure: Mechanisms of damage and therapeutic alternativesEstrés oxidativo e inflamación en insuficiencia cardiaca: Mecanismos de daño y alternativas terapéuticas
    (2007) Miranda H R.; Castro G P.; Verdejo P H.; Chiong M.; Díaz-Araya G.; Mellado R.; Rojas D.; Lavandero S.; Concepción R.; Castro G P.; Lavandero S.
    Despite advances in treatment, chronic heart failure still is associated with a poor prognosis and remains a leading cause of cardiovascular death. Cumulating evidence suggests that imbalances in redox state lead to a higher generation of reactive oxygen species. This phenomenon, along with pro-inflammatory cytokine activation and extra cellular matrix alterations with reactive fibrosis, play an important role in the pathogenesis and progression of heart failure, through the development of endothelial and myocardial dysfunction. The understanding of the underlying phenomena and the metabolic pathways involved will allow further development of therapies aiming to change the natural history of heart failure.