In vivo externalization of phosphatidylserine and phosphatidylethanolamine in the membrane bilayer and hypercoagulability by the lipid peroxidation of erythrocytes in rats.

Abstract

Phospholipid distribution across erythrocyte membrane bilayer is asymmetrical. In normal erythrocytes, entire phosphatidylserine (PS) and most of the phosphatidylethanolamine (PE) is present on the cytoplasmic side of membrane bilayer, whereas phosphatidylcholine (PC) and sphingomyelin (SM) are predominantly present at the outer side of membrane bilayer. The present study was undertaken to determine whether membrane lipid peroxidation has any effect on the distribution of PS, PE, and PC across erythrocyte membrane bilayer in vivo in an animal model. Erythrocyte membrane lipid peroxidation was induced in rats by administering phenylhydrazine, an oxidant drug. Membrane phospholipid organization was determined by using bee venom phospholipase-A2 and indirectly by measuring clotting time on recalcification of normal human platelet-poor plasma in the presence of Russell's viper venom. Phenylhydrazine administration to rats caused significant membrane lipid peroxidation as measured by the accumulation of malonyldialdehyde (MDA), an end product of fatty acid peroxidation, as well as externalization of a significant portion of PS and PE from the inner to the outer side of membrane bilayer in erythrocytes. There was a significant positive correlation (r) between the amount of MDA accumulated in the erythrocytes and the movement of PS (r = 0.92) and PE (r = 0.96) from inner to the outer membrane bilayer and PC (r = 0.81) from outer to the inner membrane bilayer. Erythrocytes of phenylhydrazine-treated rats also showed significantly reduced clotting time. This reduction in clotting time had a significant positive correlation with MDA accumulation (r = 0.92) and PS externalization (r = 0.90). Both the effect of phenylhydrazine on erythrocyte membrane lipid peroxidation and alterations in phospholipid organization and coagulability were blocked when rats were simultaneously administered with vitamin E or C antioxidants.

Diabetic Patients Without Vascular Complications Display Enhanced Basal Platelet Activation and Decreased Antioxidant Status

“…During the final stages of activation, platelets express the aminophospholipid phosphatidylserine at the platelet outer membrane surface, and this process can be induced by MDA. Indeed, previous studies (38,39) have shown that part of phosphatidylserine can move from the inner to the outer side of the membrane when cells are treated with MDA. Considering that the exposure of phosphatidylserine in the outer plasma membrane plays an important role in thrombin generation (40), this is in agreement with the increased plasma thrombin generation described in diabetic patients (41) and could contribute to the enhanced basal activation observed in the present study.…”

Oxidative stress and phosphatidylserine exposure in red cells from patients with sickle cell anaemia

“…SCA is associated with increased oxidative stress, neutrophil leucocytosis and vascular endothelial dysfunction, all of which are also associated with increased PS exposure (Jain, 1985; Hebbel, 1991; Kuypers, 1998; Mutze et al , 2003; Banerjee & Kuypers, 2004; Zhang et al , 2013). Recent reviews have reinforced the view that ROS are actively involved in lipid scrambling in SCA (Cimen, 2008; Mohanty et al , 2014; Voskou et al , 2015), with limited experimental evidence supporting this assumption.…”

Lipid Oxidation Enhances the Function of Activated Protein C

“…Membrane constituents such as plasmalogens (45,71) or sphingomyelin (72) may help stabilize minimally oxidized surfaces to maintain APC activity for a longer period. The red cell membrane could also be oxidized by the infiltrating leukocytes in addition to the platelets normally envisioned, possibly adding anticoagulant surface despite the externalization of PS and PE that can occur on these cells in response to oxidation (15).…”

“…Endothelial cells and leukocytes themselves can elaborate reactive oxygen species leading to oxidation of additional surfaces (16,24,25). Oxidation of red blood cells results in increased exposure of both PS and PE on the membrane surface, making these cells potentially procoagulant (15).…”