The authors have investigated the oxidative state of glutathione in red blood cells (RBC) and plasma from patients affected by chronic renal failure (CRF) and from age-matched healthy subjects. RBC-reduced glutatione (GSH) levels were significantly lower in CRF patients than in healthy subjects. Oxidized glutathione (GSSG) levels in plasma from CRF patients were higher than in plasma from controls. GSSG levels in RBC were similar in both groups. No differences were noted in GSH plasma levels between patients and controls. The GSSG/GSH ratios in RBC were similar in the two groups; on the contrary, the GSSG/GSH ratio in plasma was significantly higher in CRF patients. High levels of GSSG in plasma could exert two important effects on RBC: (1) inhibition of glucose-6-phosphate dehydrogenase activity, with a consequent alteration of the glutathione system; (2) GSSG easily reacts with hemoglobin to produce hemoglobin-glutathione mixed disulfides, with a consequent protein aggregation and precipitation. In vitro experiments have shown that RBC from CRF patients easily lyse when incubated with their same plasma, but not when incubated in saline buffer. Our results seem to demonstrate that plasma from CRF patients contains various oxidants which could affect the integrity of the glutathione system in RBC. This alteration could play a role in the pathogenesis of anemia in uremic patients.

Authors report on the effect of reduced glutathione parenterally administered on the anemic status in patients suffering from chronic renal failure and undergoing hemodialysis. Twenty patients were studied for 180 days and were divided into two age- and sex-matched groups. The first group (10 patients) received placebo, the second group (10 patients) received the treatment (1,200 mg of reduced glutathione). Reduced glutathione and placebo were given for 120 days in a randomized double-blind fashion and the following measurements were performed : red blood cells reduced and oxidized glutathione, plasma reduced and oxidized glutathione, hematocrit, hemoglobin, reticulocytes, serum iron, transferrin, indirect bilirubin, urea, creatinine, calcium, phosphate, parathyroid hormone and alkaline phosphatase. In the treated group, during the supplementation period, there was an increase in the levels of red blood cells and plasma reduced glutathione, hematocrit and hemoglobin and a concomitant decrease in plasma oxidized glutathione and reticulocytes with a maximum effect on the 120th day of therapy. In the placebo-treated group there were no significant variations of the parameters considered during the study period. When the therapy, on patients undergoing treatment, was terminated there was a drop in the analyzed parameters, which fell to pretreatment values at the subsequent controls. These findings seem to indicate that reduced glutathione could represent a useful drug in the treatment and management of anemia in patients affected by chronic renal failure.

Objective: Indexes of myocardial ischemia and vasoconstrictive hormonal release were evaluated in order to investigate the difference between essential hypertension and hypertension during chronic renal failure. Background: Arterial hypertension induces several cardiovascular alterations that reflect themselves either on the heart and/or on the coronary blood flow enhancing the cardiovascular risk. Since chronic renal failure can influence the neuroendocrine response, various mechanisms involved in hypertension during chronic renal failure are still unclear. High endothelin 1 (ET-1) levels have been found both in arterial hypertension and during chronic renal failure. Interestingly, either ET-1 or catecholamines seem also to be implied in the pathogenesis of myocardial ischemia. Methods: 20 hypertensive uremic and 20 essentially hypertensive patients underwent echocardiographic wall motion and wall thickening analysis performed at baseline and immediately after the end of exercise. Simultaneously, myocardial perfusion was evaluated by ^99mTc-MIBI-SPECT. In addition, plasma norepinephrine and ET-1 concentrations were measured at baseline and at peak exercise. Results: The segmental radionuclide analysis showed a greater ischemic degree in hypertensive uremic patients. Yet, we were able to identify one or more regions of the left ventricle in which both systolic thickening measurements and wall motion after exercise were impaired. After exercise, wall thickening impairment was correlated with both wall motion abnormalities (r = 0.72, p < 0.01) and MIBI ischemic grade (r = 0.82, p < 0.001). Basal and after-exercise plasmatic norepinephrine and endothelin levels were higher in hypertensive uremic than in essentially hypertensive patients. Moreover, there was a significant correlation between increments in norepinephrine concentration and MIBI perfusion defects, and between the increment in ET-1 concentration and both MIBI perfusion defects, or kinetic alterations assessed by wall motion as well as by wall thickening. Conclusions: This is the first cross-sectional study in which a higher degree of myocardial ischemia has been observed in hypertensive uremic patients combined with an enhanced plasma release of both norepinephrine and ET-1. This phenomenon may contribute to enhance the cardiovascular risk of these patients.

These results strongly suggest that the elevation in ET-1 levels was correlated with diastolic dysfunction in man. This phenomenon may have important pathophysiological implications suggesting the possibility of an early therapeutic approach in these patients.

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