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 oxidative stress.


METHODS
We measured whole blood oxidized and free levels of cysteine, homocysteine, cysteinylglycine, and glutathione by high performance liquid chromatography in women with normotensive pregnancies (n = 50), preeclampsia (n = 29), and preeclampsia complicated by the hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome (n = 16).


RESULTS
Oxidized and free levels (median [range], micromol/L) of cysteine and homocysteine were higher in women with preeclampsia than normotensive pregnancies (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 ratios of free to oxidized cysteine, homocysteine, and cysteinylglycine were lower in preeclampsia than normotensive pregnancy (2.2 [1.3-3.0] versus 2.4 [1.7-4.3], P <.001; 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 oxidized form of those thiols. In HELLP syndrome, levels of oxidized and free cysteine and levels of oxidized homocysteine were higher than normal (44 [33-63] 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 significant differences were found in oxidized glutathione levels in women with preeclampsia (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 than in those with preeclampsia (5.4 [3.3-12.7] versus 4.1 [2.3-11.6], P =.02, and 56 [28-124] versus 45 [16-166], P =.02, respectively).


CONCLUSIONS
Significantly lower ratios of free to oxidized cysteine, homocysteine, and cysteinylglycine in preeclampsia might indicate oxidative stress.
Raijmakers
M T
MT
Department of Gastroenterology, University Hospital St. Radboud, Nijmegen, Netherlands. w.peters@gastro.azn.nl
Zusterzeel
P L
PL
Roes
E M
EM
Steegers
E A
EA
Mulder
T P
TP
Peters
W H
WH
D000328:Adult; D003545:Cysteine / Q000097:blood; D004151:Dipeptides / Q000097:blood; D005260:Female; D005978:Glutathione / Q000097:blood; D017359:HELLP Syndrome / Q000175:diagnosis / Q000503:physiopathology; D006710:Homocysteine / Q000097:blood; D006801:Humans; D007231:Infant, Newborn; D015227:Lipid Peroxidation / Q000502:physiology; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D011225:Pre-Eclampsia / Q000175:diagnosis / Q000503:physiopathology*; D011247:Pregnancy; D012016:Reference Values; D013438:Sulfhydryl Compounds / Q000097:blood*
D004151:Dipeptides; D013438:Sulfhydryl Compounds; D006710:Homocysteine; C028505:cysteinylglycine; D005978:Glutathione; D003545:Cysteine