Existence of compensatory defense mechanisms against oxidative stress and hypertension in preeclampsia.
OBJECTIVE
Preeclampsia is a complex obstetrical syndrome characterized by hypertension and proteinuria. This syndrome is associated with oxidative stress, antioxidant imbalance and impaired production of vasoactive eicosanoids such as thromboxane A(2) (TXA(2)), a potent vasoconstrictor, and prostacyclin (PGI(2)), a well-known vasodilator. We hypothesized that there was a relationship between antioxidant vitamins, such as vitamin E and coenzyme Q(10) (CoQ(10)), and the production of vasoactive eicosanoids- PGI(2) and TXA(2)-potentially regulated by pro-oxidants and antioxidants in preeclampsia.


METHODS
Therefore, the plasma levels of vitamin E, CoQ(10), TXA(2) and PGI(2) in normotensive (n = 30) and preeclamptic (n = 29) pregnancies were evaluated. Reduced and oxidized forms of vitamin E and CoQ(10) in blood were measured using a HPLC coupled to electrochemical detection. The levels of TXB(2) and 6-keto-PGF(1alpha), stable metabolites of TXA(2) and PGI(2) respectively, were measured by ELISA.


RESULTS
The CoQ(10) oxidized/reduced ratio was significantly higher in preeclamptic compared to normotensive pregnancies (p = 0.04). A strong correlation between plasma levels of reduced vitamin E and CoQ(10), corrected for apolipoprotein B, was observed only in preeclampsia (r = 0.69, p < 0.0001). The 6-keto-PGF(1alpha)/TXB(2) ratio was higher in preeclampsia than in controls (p = 0.02), and this ratio was correlated to the oxidized/reduced ratio of both, vitamin E and CoQ(10) in all pregnancies (p <0.023).


CONCLUSIONS
The data indicated that CoQ(10) is a sensitive marker of oxidative stress in preeclampsia. The correlation between vitamin E and CoQ(10) suggested a coordinated defense mechanism against oxidation. Furthermore, the higher 6-keto-PGF(1alpha)/TXB(2) ratio that strongly correlated with oxidative stress markers, suggests a mechanism developed by the maternal cardiovascular system to counteract hypertension during preeclampsia.
Roland
L
L
Centre de Recherche du Centre Hospitalier de l'Université Laval, Québec, Canada.
Gagné
A
A
Bélanger
M-C
MC
Boutet
M
M
Berthiaume
L
L
Fraser
W D
WD
Julien
P
P
Bilodeau
J-F
JF
D000328:Adult; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D011464:Epoprostenol / Q000097:blood; D005227:Fatty Acids / Q000097:blood; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D018384:Oxidative Stress; D018579:Patient Selection; D011225:Pre-Eclampsia / Q000097:blood / Q000503:physiopathology*; D011247:Pregnancy; D013928:Thromboxane A2 / Q000097:blood; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000097:blood; D014810:Vitamin E / Q000097:blood
D005227:Fatty Acids; D014451:Ubiquinone; D014810:Vitamin E; D013928:Thromboxane A2; D011464:Epoprostenol; C024989:coenzyme Q10