Studies of the Role of Red Cell Membrane Peroxidation in Paroxysmal Nocturnal Haemoglobinuria (PNH)*

Abstract

Summary. No evidence was found to support the claimed role of lipid peroxidation in the pathogenesis and haemolysis in paroxysmal nocturnal haemoglobinuria (PNH) including iron‐induced episodes of gross haemoglobinuria. Therapy with the antioxidant vitamin E failed to influence the course of two patients with PNH. Three separate techniques for inducing lipid peroxidation failed to lower AChE of normal and PNH red cells and to induce susceptibility to in vitro PNH haemolytic tests in normal cells whether iron was added to the test system or not. Under peroxidatic stress, PNH cells did not generate abnormally high amounts of lipid peroxides as measured by malonaldehyde formation. Similar results were obtained with human red cells with induced high concentrations of protoporphyrin IX. Such studies do not, however, vitiate the concept that lipid peroxidation may play an important role in biologic ageing and cell destruction.

The Effect of Vitamin E on Haemolysis in Paroxysmal Nocturnal Haemoglobinuria: In vitro and in vivo Studies

“…Using these indices to monitor the degree of haemolysis, no significant beneficial effect of vitamin E could be demonstrated in the patient studied. This result is similar to that recently reported by Paniker et al (1974) who failed to show any response with respect to haemoglobinuria or transfusion requirements in two patients with PNH treated for more than 5 months with vitamin E. These findings, together with the failure to demonstrate decreased levels of vitamin E in the sera of patients with PNH (Mengel et a1 1967) suggest that membrane lipid peroxidation may not be a major factor in the pathogenesis of the disease. In contrast to the lack of effect in vivo, an unequivocal effect of vitamin E in reducing the degree of peroxide-induced haemolysis in the red cells of four patients with PNH, including the patient studied in vivo, was demonstrated.…”

Changes in the Activities of some Membrane‐associated Enzymes during in Vivo Ageing of the Normal Human Erythrocyte

“…The former phenomenon was observed in the case of NADH-ferricyanide reductase following nonionic surfactant treatment (Fig 6), the Table I1 it is assumed that the activity observed in the presence of surfactant represents the total membrane activity. As there is some circumstantial evidence that in vivo ageing is associated with autoxidation of lipids (Stocks et al, 1972;Paniker et al, 1974;Goldstein & McDonagh, 1976) it is possible that the resulting lipid peroxides fulfil this role. The value quoted for each age fraction is the activity determined in the absence of nonionic surfactant expressed as a percentage of that determined in the presence of the surfactant mixture as shown in Fig 6. The physiological substrate of NADH-ferricyanide reductase, in view of the high degree of crypticity involved, is likely to be a component of the hydrophobic core of the membrane.…”

“…The value quoted for each age fraction is the activity determined in the absence of nonionic surfactant expressed as a percentage of that determined in the presence of the surfactant mixture as shown in Fig 6. The physiological substrate of NADH-ferricyanide reductase, in view of the high degree of crypticity involved, is likely to be a component of the hydrophobic core of the membrane. As there is some circumstantial evidence that in vivo ageing is associated with autoxidation of lipids (Stocks et al, 1972;Paniker et al, 1974;Goldstein & McDonagh, 1976) it is possible that the resulting lipid peroxides fulfil this role. If this is the case then it may be that lipid peroxides accumulate in the membrane as the erythrocyte ages and this could possibly constitute the primary membrane event leading to the eventual removal of the aged cell from the circulation.…”

Susceptibility to Autoxidation of Lipids of Paroxysmal Nocturnal Hemoglobinuria (PNH)-Like Red Cells

“…Increased susceptibility to autoxidation of red cell lipids was also found by Russian authors [11] both in their 20 cases of PNH and in PNH-like cells produced after treatment with proteolytic enzymes or GSH, by Stocks et al [24] in their sole case of PNH, and by us in one case we had the opportunity to study; P aniker et al [18], how ever, failed to confirm this finding in their 5 PNH patients. In this con text, it is noteworthy that the formation of PNH-like cells by treatment with sulfydryl compounds was not inhibited by the absence of oxygen [6,9], iron or accumulation of H20 2 [15]; such findings make lipid peroxida tion unlikely to be the cause of the PNH-like transformation.…”

“…Among the many factors claimed to be involved in the PNH corpuscu lar defect, rendering the red cell susceptible to damage and lysis, is in creased vulnerability of the red cell lipids to autoxidation [13,14,16], but the contribution of this factor has been doubted [18].…”