Oxidized and free whole blood thiols in preeclampsia

Objective: To measure levels of oxidized and free thiols in whole blood of normotensive pregnant and preeclamptic women and evaluate the role of oxida tive stress. Methods: We measured whole blood oxidized and free levels of cysteine, homo cysteine, cysteinylglycine, and glutathione by high performance liquid chro matography in women with normotensive pregnancies (n = 50), preeclampsia (n = 29), and preeclampsia complicated by the hemolysis, elevated liver enzym es, low platelets (HELLP) syndrome (n = 16). Results: Oxidized and free levels (median [range], mu mol/L) of cysteine an d homocysteine were higher in women with preeclampsia than normotensive pre gnancies (45 [27-81] versus 29 [9-91], P <.001, and 98 [57-193] versus 69 [ 33-215], P <.001; 0.8 [0.2-4.4] versus 0.4 [0.01-1.6], P <.001, and 2.1 [0. 7-9.4] versus 1.2 [0.2-21.2], P<.01; respectively). The Patios of free to o xidized cysteine, homocysteine, and cysteinylglycine were lower in preeclam psia than normotensive pregnancy (2.2 [1.3-3.0] versus 2.4 [1.7-4.3], P <.0 01; 2.3 [0.5-5.4] versus 2.9 [1.1-24], P <.001; 4.1 [2.3-11.6] versus 5.4 [ 2.6-24.3], P <.02, respectively), indicating a shift in favor of the oxidiz ed form of those thiols. In HELLP syndrome, levels of oxidized and free cys teine and levels of oxidized homocysteine were higher than normal (44 [33-6 3] versus 29 [9-91], P <.001, and 102 [82-133] versus 69 [33-215], P <.001; 1.0 [0.3-2.9] versus 0.4 [0.01-1.6], P <.001, respectively). No significan t differences were found in oxidized glutathione levels in women with preec lampsia (22 [5-49] versus 17 [2-60], P =.06) or free levels in preeclamptic women with HELLP syndrome (757 [624-993] versus 842 [539-1516], P =.09) as compared with normotensive pregnant women. The ratios of free to oxidized cysteinylglycine and glutathione were higher in women with HELLP syndrome t han in those with preeclampsia (5.4 [3.3-12.7] versus 4.1 [2.3-11.6], P =.0 2, and 56 [28-124] versus 45 [16-166], P =.02, respectively). Conclusion: Significantly lower ratios of free to oxidized cysteine, homocy steine, and cysteinylglycine in preeclampsia might indicate oxidative stres s. (Obstet Gynecol 2001;97: 272-6. (C) 2001 by The American College of Obst etricians and Gynecologists.).