Damage to the structure of erythrocyte plasma membranes in patients with type-2 hypercholesterolemia.
BACKGROUND
Hypercholesterolemia may decrease the deformability of red blood cells which impairs their hemorheological behavior and promotes atherosclerosis. The study involved 60 hypercholesterolemic patients and 30 healthy individuals as the control group.


METHODS
The membrane fluidity of erythrocytes was estimated by a spin-label method (5-doxylstearic acid (5-DSA)). The ratio of weakly to strongly (W/S) immobilized residues of erythrocyte membrane-bond maleimide-tempo spin label was studied in oxidative damage to membrane protein. Damage to erythrocyte proteins was also indicated by means of Na(+) K(+) ATPase activity.


RESULTS
The membranes of hyperlipidemia (hlp) patients contain larger concentrations of cholesterol 2.16+/-0.24 than do those of the normolipemic individuals 0.31+/-0.24 (P<0.001). The level of Na(+) K(+) ATPase in the erythrocyte membrane from the control group was higher 103.4+/-1.3 (nmolPi/(mgproteinsh)) than in the patient group 93.6+/-3.2 (nmolPi/(mgproteinsh)) (P<0.001). The order parameter S 5-DSA in the control group was 0.745+/-0.009 and in hlp patients was 0.755+/-0.009 (P<0.001). The W/S ratio in the control group amounted to 2.00+/-0.09 and in the hlp patient group was 2.50+/-0.11 (P<0.001).


CONCLUSIONS
Type-2 hypercholesterolemia causes changes in the structure and fluidity of erythrocyte plasma membranes since the excess of cholesterol affects the normal rheology of blood through its interaction with erythrocytes. It also impairs the function and structure of plasma membrane proteins.
Koter
Maria
M
Department of Environment Pollution Biophysics, University of Lodz, 12/16 Banacha St., 90-347, Lodz, Poland. koterm@biol.uni.lodz.pl
Franiak
Ida
I
Strychalska
Karolina
K
Broncel
Marlena
M
Chojnowska-Jezierska
Julita
J
D016022:Case-Control Studies; D003497:Cyclic N-Oxides / Q000494:pharmacology; D004907:Erythrocyte Deformability; D004910:Erythrocyte Membrane / Q000473:pathology*; D004912:Erythrocytes / Q000473:pathology*; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood* / Q000473:pathology*; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013113:Spin Labels
D003497:Cyclic N-Oxides; D013113:Spin Labels; C017480:4-maleimido-2,2,6,6-tetramethylpiperidinooxyl; C032363:16-nitroxystearic acid; D000254:Sodium-Potassium-Exchanging ATPase; D010100:Oxygen