Stress In Red Blood Cells Research Articles

Vitamin E Consumption Induced by Oxidative Stress in Red Blood Cells Is Enhanced by Melatonin and Reduced by N-Acetylserotonin

The effect of melatonin and its precursor N-acetylserotonin was studied in a model of lipid peroxidation induced in human red blood cells by incubation with cumene hydroperoxide (CHP) and H 2O 2. The oxidative stress was expressed as vitamin E consumption in the presence of melatonin or N-acetylserotonin (concentration ranging from 0.3 to 400 μM): incubation with melatonin not only lacked any protective effect but it induced a dose-dependent extra vitamin E consumption with both CHP and H 2O 2. On the contrary, N-acetylserotonin showed a strong antioxidant effect at concentrations between 100 and 400 μM. The hydrogen-donating capacity of melatonin and N-acetylserotonin was also evaluated from the decay of the ESR signal of galvinoxyl radical used as hydrogen abstractor. Lack of hydrogen-donating capacity was observed with melatonin, whereas N-acetylserotonin showed a significant hydrogen-donating capacity althought inferior to vitamin E, thus suggesting that N-acetylserotonin acts by the classical antioxidant mechanism of hydrogen donation. The measurement of the oxidation potential and the specific molecular structure suggest that the vitamin E consumption effect observed with melatonin could be due to the interactions of its radical cation or derivatives on vitamin E.

D-amino acids in aging erythrocytes.

Mature human erythrocytes are highly differentiated cells which have lost the ability to biosynthesize proteins de novo. During cell aging in circulation, erythrocyte proteins undergo spontaneous postbiosynthetic modifications, regarded as "protein fatigue" damage, which include formation of isomerized and/or racemized aspartyl residues. These damaged proteins cannot be replaced by new molecules; nevertheless, data support the notion that they can be repaired to a significant extent, through an enzymatic transmethylation reaction. This repair reaction has therefore been used as a means to monitor the increase of altered aspartyl residues in erythrocyte membrane proteins during cell aging. The relationship between protein repair and aspartyl racemization in red blood cell stress and disease is discussed.

Osmotic stress in red blood cells from Beagles with hemolytic anemia

Summary Red blood cell populations separated by density centrifugation were compared in a dynamic assay of osmotic stress. Red blood cells from Beagles genotypically normal and nonanemic (nonaffected), Beagles with inherited hemolytic anemia (anemic), and Beagles presumed to be carriers of the anemia trait (trait carriers) were examined for rate and extent of swelling after exposure to the ionophore A23187 in a medium containing calcium and potassium chloride. Comparisons were made between rbc populations separated on the basis of density. Significant differences were observed in the rates of cell swelling in rbc populations separated by density between nonaffected and anemic Beagles. The response of rbc from Beagles presumed to carry the anemia trait was similar to that of rbc from nonaffected dogs. One phenotypic expression of this inherited abnormality of rbc in Beagles was an accelerated rate of rbc swelling under osmotic stress, and this swelling response diminished with increasing rbc density.

Red Blood Cell Susceptibility to Lipid Peroxidation, Membrane Lipid Composition, and Antioxidant Enzymes in Continuous Ambulatory Peritoneal Dialysis Patients

To investigate the overall susceptibility of red blood cells (RBC) to lipid peroxidation from patients on continuous ambulatory peritoneal dialysis (CAPD). The following parameters were measured: RBC malondialdehyde (MDA) production after oxidative stress with H2O2, RBC antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), and RBC membrane lipid composition. The levels of plasma vitamin E and serum selenium were also assayed. Eleven patients on continuous ambulatory peritoneal dialysis. Twenty-one healthy blood donors of similar age were used as normal controls. The MDA formation after H2O2 stimulation was normal in CAPD patients (0.79 +/- 0.1 mumol/gHb versus 0.78 +/- 0.1 in the control group). RBC from CAPD patients also showed a normal SOD activity, a more than adequate vitamin E status, and a peculiar pattern of membrane lipids, with reduced polyunsaturated fatty acids (p less than 0.001) and increased monounsaturated fatty acids (p less than 0.001). Both RBC GSH-Px activity, a selenium-dependent enzyme, and serum selenium levels were significantly lower in CAPD patients, and a significant positive correlation (r = 0.68; p less than 0.02) between the two parameters was found. This study found a normal sensitivity to oxidant stress in RBC from a group of CAPD patients, despite an impaired GSH-Px activity. The peculiar lipid pattern of RBC membrane, characterized by reduced PUFA and increased MUFA content, may contribute, in addition to adequate SOD activity and vitamin E status, to normal RBC lipid peroxidation.

Kinetics and site specificity of hydroperoxide-induced oxidative damage in red blood cells

To provide a detailed description of the time course and the site specificity of hydroperoxide-induced oxidative stress in red blood cells (RBCs), we have characterized the action of a membrane-soluble (cumene hydroperoxide [cumOHH]) and a water-soluble (hydrogen peroxide [H 2O 2]) oxidant. The fluorescent polyunsaturated fatty acid (PUFA) parinaric acid (PnA) was used to probe peroxidation processes in the membrane, and oxidation of hemoglobin (Hb) was measured spectrophotometrically as an indicator of cytosolic oxidative stress. The observed degradation patterns of PnA and Hb were clearly distinct for each oxidant. At comparable oxidant concentrations, the cumulative oxidative stress on the RBC membrane was always much higher with cumOOH, whereas much more Hb oxidation was measured with H 2O 2. The kinetics of Hb oxidation as well as the nature of the products formed were different for each oxidant. The main Hb oxidation product generated gradually by cumOOH was metHb, whereas H 2O 2 caused the rapid formation of ferrylHb. ComOOH caused more oxidation of endogenous PUFAs and of vitamin E, while the degradation pattern of vitamin E closely resembled that of PnA. At high oxidant concentrations, extensive cell lysis was observed after prolonged incubation. Butylated hydroxytoluene (BHT) completely prevented oxidation of endogenous PUFAs but did not completely prevent hemolysis, indicating that factors other than lipid peroxidation are also important in causing lysis of RBCs. The action of cumOOH is characterized by a gradual reaction with Hb, generating radicals that produce an oxidative stress primarily directed at the membrane, which increases in time to a maximum and then gradually decreases. In contrast, H 2O 2 crosses the RBC membrane and reacts rapidly with Hb, generating a very reactive radical species that has Hb, not the membrane, as a prime target. H 2O 2-induced oxidative stress is at a maximum immediately after addition of this oxidant and decreases rapidly to zero in a short time. These findings provide further insight into the mode of action of hydrperoxides and the mechanism of compartmentalization of RBC oxidative damage.

The hydrolytic autoxidation of 1,4-naphthoquinone-2-potassium sulphonate: Implications for 1,4-naphthoquinone-2-potassium sulphonate-induced oxidative stress in the red blood cell

1,4-Naphthoquinone-2-potassium sulphonate (NQKS) undergoes an autoxidation reaction in aqueous solution under physiological conditions to produce 3-hydroxy-1,4-naphthoquinone-2-potassium sulphonate (NQKS-OH). Intermediates of dioxygen reduction, superoxide radicals, hydrogen peroxide and hydroxyl radicals, are also detected. The kinetics of the autoxidation of NQKS show a first order dependence on NQKS and hydroxide ion concentration and a zeroth order dependence on oxygen concentration. For the rate equation r = − d[O 2]/ dt = k obs., [NQKS][ −OH], k obs. = (6.4 ± 0.6) × 10 2 M −1 s −1 at 37°C. Hydroxide ion attack on NQKS appears to be the rate determining step. The reaction may be conveniently described as a ‘hydrolytic autoxidation’. The hydrolytic autoxidation of NQKS occurs in NQKS-treated red blood cells; the hydroxylated quinone NQKS-OH is produced and hydroxyl radical formation is stimulated. The importance of this reaction in NQKS-induced oxidative stress in red blood cells is discussed. The hydrolytic autoxidation of quinones bearing one or more unsubstituted (hydrogen) positions on the quinone centre is a novel mechanism by which such quinones may induce oxidative stress in cellular systems.

Macroangiopathic Hemolytic Anemia Due to Congenital Cardiovascular Anomalies

Hemolytic anemia due to vascular trauma occurred in a boy with congenital cardiovascular anomalies that included aortic coarctation and bicuspid aortic valve. Turbulent stress of red blood cells passing through deformed orifices is deemed responsible for the traumatic damage and ensuing hemolysis in this patient.

Macroangiopathic hemolytic anemia due to congenital cardiovascular anomalies

Hemolytic anemia due to vascular trauma occurred in a boy with congenital cardiovascular anomalies that included aortic coarctation and bicuspid aortic valve. Turbulent stress of red blood cells passing through deformed orifices is deemed responsible for the traumatic damage and ensuing hemolysis in this patient.