Effects of nitroglycerin on the uterine and umbilical circulation in severe pre-eclampsia

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Journal of Gynecology di Obstetrics 53 (19%) 205-214

nitric oxide

Ghabour MS.; Eis A.L.W.; Brockman D.E.; Pollock J.S.; Myatt L. USA AM J OBSTET GYNECOL 1995 173/3 I (687-694) Objective: Our purpose was to compare the expression of endothelial nitric oxide synthase in the placenta and umbilical cord of pre-eclamptic placenta with that of the normotensive placenta. Study design: We compared placental endothelial nitric oxide synthase expression in pre-eclamptic (n = 3) with that in normal (n = 3) pregnancies.Frozen sectionsof umbilical cords, chorionic plate vessels,and terminal villi were immunosmined with a monoclonal endothelial nitric oxide synthaseantibody (H32). Rest&s: No difference in endothelial nitric oxide synthase.immunostaining in the endothelimn of the umbilical cord artery and vein, chorionic plate vessels,and stem villous vessels was found between pre-eclamptic and normotensive pregnancies. In contrast, in the pre-eclamptic placentas endothelial nitric oxide synthase immunostaining was seen in the small terminal villous vesselswith underlying smooth muscle layer. In the syncytiotrophoblast, endothelial nitric oxide synthase immunostaining appeared primarily apical in location and diffuse in distribution in the pre-eclamptic placentas but primarily basal and punctate in the normotensive placentas. Conclusions:Differences in endothelial nitric oxide synthaseexpression in terminal villous vesselsand in syncytiotrophoblast may be a result of vascular alterations or damage that take place in the placenta in pre-eclampsia. These differences may alter the regulation of blood flow in the fetal and maternal placental vasculatures in pre-eclampsia. Nitric oxide comenlvatiom CiralIation hl pre-ecIam~a

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Lyall F.; Young A.; Greer LA. GBR

AM J OBSTET GYNECOL 1995 173/3 1(714-718) Objective: The aim of this study was to measureserum concentrations of total nitrites, as an index of nitric oxide synthesis, in the maternal and fetal circulations of normal pregnanciesand in pregnancies complicated by pre-eclampsia. Srudy &sign: We studied 32 women with pre-eclampsia and 36 with uncomplicated pregnancies. Maternal venous blood samples were collected from all of the patients, and umbilical venous blood was collected from 13 of the pre-eclamptic group and 17of the control group. Serum nitric oxide concentrations were determined with the Greiss reaction by measuring combined oxidation products of nitric oxide, serum nitrite and nitrate after reduction with nitrate reductase.Reds: There were no significant differences in maternal serum nitrite concentrations between the groups (control group 29.8 * 1.07 pmol/l, pre-eclamptic group 29.5 f 1.06 mol/l). Signiticantly higher serum nitrite concentrations were found in umbilical venous serum in the pte-eclamptic group compared with the control group (34.59 f 1.12ronol/I vs. 23.90 f 1.05PmohI, P < 0.01). Conclusions: Total nitrites are increased in the fetoplacental circulation in pre-eclampsia.These results support the hypothe-

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sis that increased nitric oxide production may be a compensatory responseto improve blood flow or may play a role in limiting platelet adhesion and aggregation. Effectsofnitn@ycerinootkoterinemidlrmbiKcdcivcahtioa in severe predampmia

Grunewald C.; Kublickas M.; Carlstrom K.; Lunch N.-G.; Nisell H. SWE

OBSTET GYNECOL 1995 86/4 I (600-604) Objective: To determine the effects of nitroglycerin on placental circulation in severepm-eclampsia. Methoak Twelve women with severepre-eclampsia were examined. Uterine and umbilical artery puhatility indices (PI) were assessedby pulsed Doppler ultrasound before and after infusion of nitroglycerin, starting at 0.25 @kg/mitt with stepwise dosage increasesuntil a diastolic blood pressure (BP) of 100 mmHg was achieved. Blood pressureand heart rate were recorded every 5 min. Blood was sampled for analysis of the second messenger of nitric oxide, cyclic guanosinemonophosphate (cGMP) before and at the end of the infusion. Results: During the infusion, the mean systolic BP decreasedfrom 161(95% confidence interval (C.I.) 154-169) to 138mmHg (95% C.I. 131-1461), and the diastolic pressuredecreasedfrom 116 (95% C.I. 11l-122) to 103 (95% C.I. 96-l 10)mmHg (P < 0.01).The PI of the uterine artery did not change significantly (1.23, 1.01-1.61) versus (1.30, 1.Ol- 1.88).whereas umbilical artery PI decreasedsignificantly (P < O.Ol), from 1.35 (1.09-1.73) to 1.20 (1.05-1.40), with a more pronounced decreasein patients with high basal values. Cyclic GMP remained essentially unchanged (6.4, 5.4-7.7 vs. 5.5.4.7-6.6 nmokl). Conclusions: The reduction in the PI of the umbilical artery during nitroglycerin-induced BP reduction implies vascdilation in the umbilical circulation. The absence of an increase in cGMP does not support the view that the nitroglycerin effect is reflected by the plasma concentration of cGMP. TlleangkmiadvitytestaadIowdneeaspIrhlueiaeffeelive methods to pdkt nod prevent bypebmive dbders

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Kyle P.M.; Buckley D.; Kissane J.; De Swiet M.; Redman C.W.G. GBR

AM J OBSTET GYNECOL 1995 17313I (865-872) Objective: Our purpose was to assessthe efficiency of the angiotensin sensitivity test as a predictive test for pre-eclampsia and the effectiveness of low-dose aspirin to prevent pmeclampsiawhen commencedat 28 weeks’ gestation in angiotensin II-sensitive women. Study design: A total of 495 healthy nulliparous women underwent the angiotensin sensitivity test at 28 weeks’ gestation. The angiotensin II-sensitive women were randomized to 60 mg of aspirin or placebo as a subsetof a large multicenter randomized controlled trial of low-dose aspirin therapy in pregnancy. Assessmentof the efftciency of the angiotensin sensitivity test and low-dose aspirin in pregnancy was performed after detailed review of casenotes after de very. The Oxford definition of pre-eclampsia was used. This includes