Effect of vitamin E-bonded membrane on the 8-hydroxy 2'-deoxyguanosine level in leukocyte DNA of hemodialysis patients.
BACKGROUND
8-Hydroxy 2'-deoxyguanosine (8-OHdG) of leukocyte DNA has been identified as a surrogate marker of oxidative stress in chronic hemodialysis (HD) patients. In this study, we focused on the determinants of the 8-OHdG level in leukocyte DNA of HD patients. We further investigated the influence of vitamin E-modified, regenerated cellulose (CL-E) membrane on the oxidative DNA damage, intracellular reactive oxygen species (ROS) production of granulocytes, and plasma alpha-tocopherol concentration.


METHODS
8-OHdG content in cellular DNA of leukocytes was measured by a high-performance liquid chromatography-electrochemical detection (HPLC-ECD) method. Intracellular production of ROS, H2O2 and O2-. were analyzed by flow cytometry in leukocytes with and without phorbol-12-myristate-13-acetate (PMA) stimulation before dialysis, as well as at 15 and 30 minutes of dialysis. Plasma alpha-tocopherol concentration was measured by a HPLC method, and the value of alpha-tocopherol was corrected by total blood lipid concentration.


RESULTS
In the prospective cross sectional study, the mean 8-OHdG level in leukocyte DNA was equally lower in the patients of the CL-E, polymethylmethacrylate (PMMA), and polysulfone (PS) groups as compared with the cellulosic group (ANOVA, P < 0.001). The leukocyte 8-OHdG level correlated negatively with plasma alpha-tocopherol and blood lipid-adjusted plasma alpha-tocopherol, but correlated positively with serum iron and percentage of transferrin saturation. Forward stepwise multiple regression showed that dialysis membrane type, serum iron, and blood lipid-adjusted plasma alpha-tocopherol were the independent determinants of the leukocyte 8-OHdG level in HD patients. Like synthetic membranes, granulocyte ROS production was less augmented during dialysis with the CL-E membrane as compared with the cellulose membrane. Exposure to cellulose membrane impaired intracellular ROS production of granulocytes in response to PMA challenge, whereas the CL-E and synthetic membranes improved the granulocyte responsiveness to PMA. In the longitudinal cross-over study, the 8-OHdG level significantly decreased, and blood lipid-adjusted plasma alpha-tocopherol increased after switching the cellulose membrane to CL-E or synthetic membrane for eight weeks. In contrast, the 8-OHdG level dramatically rose, and blood lipid-adjusted plasma alpha-tocopherol declined after shift of CL-E or synthetic membrane to the cellulose membrane.


CONCLUSIONS
CL-E membrane exhibited biocompatible and bioactive characteristics. Like synthetic membranes, treatment with a CL-E dialyzer effectively reduced the 8-OHdG content in leukocyte DNA, suppressed intracellular ROS production of granulocytes, and preserved the plasma level of vitamin E. It could further improve granulocyte responsiveness to a PMA challenge. Reduced DNA damage and improved immune function of leukocytes may reduce the cancer and infection risks in chronic HD patients.
Institute of Clinical Medicine, Department of Biochemistry and Center for Cellular and Molecular Biology, National Yang-Ming University, Taipei, Taiwan.
D C
DC
Tarng
T P
TP
Huang
T Y
TY
Liu
H W
HW
Chen
Y J
YJ
Sung
Y H
YH
Wei
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D000368:Aged; D001205:Ascorbic Acid / Q000097:blood; D001672:Biocompatible Materials / Q000627:therapeutic use; D001843:Bone Cements / Q000627:therapeutic use; D002482:Cellulose / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D004247:DNA / Q000032:analysis; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007676:Kidney Failure, Chronic / Q000628:therapy*; D007962:Leukocytes / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D011108:Polymers / Q000627:therapeutic use; D019904:Polymethyl Methacrylate / Q000627:therapeutic use; D011446:Prospective Studies; D006435:Renal Dialysis / Q000295:instrumentation*; D013450:Sulfones / Q000627:therapeutic use; D014810:Vitamin E / Q000097:blood / Q000627:therapeutic use*
D001672:Biocompatible Materials; D001843:Bone Cements; D008567:Membranes, Artificial; D011108:Polymers; D013450:Sulfones; D014810:Vitamin E; C017662:polysulfone P 1700; D000080242:8-Hydroxy-2'-Deoxyguanosine; D002482:Cellulose; D004247:DNA; D019904:Polymethyl Methacrylate; D006861:Hydrogen Peroxide; D003849:Deoxyguanosine; D001205:Ascorbic Acid