Low plasma glutathione levels after reperfused acute myocardial infarction are associated with late cardiac events.

OBJECTIVE: To clarify whether an altered redox state persists in the subacute phase of myocardial infarction and if specific redox patterns are associated with later cardiac events. METHODS: Ninety-seven patients [80 men, median 63 (interquartile range, 53, 69) years] with a first acute myocardial infarction, with (53%) or without ST segment elevation, treated with successful percutaneous interventions, were tested at 5-6 days after admission for plasma alpha-tocopherol, ascorbic acid, total and reduced homocysteine, cysteine, glutathione, cysteinylglycine and blood-reduced glutathione, all assessed by high-pressure liquid chromatography. Free malondialdehyde was evaluated by gas chromatography. A subgroup of 14 patients had adjunctive blood samples within 1 h and at 72 h after angioplasty. Blood samples from 44 patients matched for age, sex, and risk factors served as controls. Patients were followed up for median 15 (interquartile range, 9, 17) months for cardiac events. RESULTS: All plasma-reduced aminothiols, vitamins and plasma total glutathione were significantly lower in myocardial infarction at 5-6 days than in controls. In the 14 myocardial infarction patients sampled repeatedly, plasma-reduced glutathione, cysteinylglycine, total glutathione, and alpha-tocopherol significantly decreased, whereas blood-reduced glutathione, total homocysteine, and cysteine significantly increased over time. During follow-up, 20 of 97 (21%) patients had adverse cardiac events. Multivariate analysis revealed that only plasma-reduced glutathione was independently associated with events (hazard ratio 0.42, 95% confidence interval 0.18-0.99, P=0.04). CONCLUSIONS: Acute myocardial infarction patients have an altered redox state at 5-6 days after successful reperfusion with respect to controls. Low plasma levels of reduced glutathione at discharge are associated with cardiac events at follow-up.

Serum to urinary sodium concentration ratio is an estimate of plasma renin activity in congestive heart failure.

We investigated the relationship between plasma renin activity (PRA) and serum ([sNa(+)]) and urinary ([uNa(+)]) sodium concentrations in 124 congestive heart failure (CHF) patients (II-IV NYHA class) and 20 healthy subjects. According to PRA (> or <3 ng ml(-1) h(-1)) and [sNa(+)] (> or <135 mEq l(-1)), patients were classified as Group A (normal PRA and normal [sNa(+)], n=39), Group B (increased PRA and normal [sNa(+)], n=62) and Group C (low [sNa(+)], n=23). Measurements were performed at rest and, in 26 cases, after extracorporeal ultrafiltration (UF). At rest, [sNa(+)] and [uNa(+)], and their difference ([sNa(+)]-[uNa(+)]), were linearly correlated with PRA, but the values did not allow differentiation of control subjects from patients or differentiation of patients with from those without renin-angiotensin system (RAS) activation. Conversely, the [sNa(+)]/[uNa(+)] ratio showed the best correlation with PRA (r=0.79, P<0.0001). UF-induced PRA changes were linearly correlated with [sNa(+)]/[uNa(+)] ratio changes (r=0.67, P=0.002), but not with those of [sNa(+)], [uNa(+)] and [sNa(+)]-[uNa(+)]. In CHF, the [sNa(+)]/[uNa(+)] ratio best correlates with PRA and reflects the basal activity as well as the rapid changes (as those induced by UF) of the RAS. Therefore, it can be considered a strong and easily available marker of PRA.