Platelets, February 2012; 23(1): 26–35 Copyright ß 2012 Informa UK Ltd. ISSN: 0953-7104 print/1369-1635 online DOI: 10.3109/09537104.2011.589543 ORIGINAL ARTICLE Nitric oxide and peroxynitrite platelet levels in gestational hypertension and preeclampsia LAURA MAZZANTI 1 , FRANCESCA RAFFAELLI 1 , ARIANNA VIGNINI 1 , LAURA NANETTI 1 , PAOLA VITALI 2 , VIRGINIA BOSCARATO 2 , STEFANO R. GIANNUBILO 2 , & ANDREA L. TRANQUILLI 2 1 Department of Biochemistry, Biology and Genetics, Marche Polytechnic University, via Tronto 10 – 60128 Ancona (Italy) and 2 Department of Obstetrics and Gynaecology, Marche Polytechnic University, via Tronto 10 – 60128 Ancona (Italy) Abstract The aim of the study was to investigate platelet nitric oxide (NO) pathways in women with Gestational Hypertension (GH), Preeclampsia (PE) and Controls. Platelet NO x and peroxynitrite (ONOO  ) levels, inducible (iNOS) and endothelial nitric oxide synthase (eNOS) and Nitrotyrosine expression (N-Tyr) in 30 women with GH, 30 with PE and 30 healthy pregnant controls, age, parity and gestational age-matched, were assessed. Platelet NO x and ONOO  levels were significantly higher in GH and PE vs. Controls, with higher levels in GH vs. PE. At the same way, iNOS and N-Tyr were significantly higher in GH and PE vs. Controls, with higher levels in GH vs. PE. Since GH expressed higher amount of NO metabolites and higher activation of iNOS compared to PE, we can hypothesize that the severity of hypertensive pathology is almost not related to only NO metabolism, this research confirmed that GH and PE are associated with marked changes in NO pathways; it is not easy to understand if they could be interpreted as causes or consequence of these pathologic states. Keywords: Preeclampsia, gestational hypertension, nitric oxide, peroxynitrite, platelets Introduction Several conditions are grouped under the term ‘‘hypertensive disorders of pregnancy’’ such as ges- tational hypertension (GH), preeclampsia (PE), chronic hypertension and superimposed preeclamp- sia on chronic hypertension; they represent 10–15 % of all pregnancies [1]. PE, the hypertensive disorder specific to human pregnancy, is a serious complication of pregnancy and a leading cause of maternal-foetal morbidity and mortality. It is a multisystem disorder affect- ing 2% of all first pregnancies, that develops after the twentieth week of pregnancy; PE has clinical diagnostic features of hypertension and protein- uria, but in its early stages, women often show no symptoms [2]. When high blood pressure is not accompanied by the proteinuria, it is referred to as GH or Pregnancy-induced hypertension (PIH). Currently, PE and GH are considered either separate diseases affecting similar organs or differ- ent severities of the same underlying disorder. According to the latter hypothesis, gestational hypertension is merely an early or mild stage of preeclampsia, perhaps preceding renal involvement and thus proteinuria [3]. GH may progress to PE, so all women who develop high blood pressure in pregnancy are monitored closely. Both PE and GH are regarded as very serious conditions and they require careful monitoring of mother and foetus. Although the aetiology of PE is unclear, there exists accumulated evidence for a pathogenic model whereby a deficiency in trophoblastic invasion of the placental bed leads to a poorly perfused fetoplacental unit. The clinical features, due to a combination of endothelial damage, generalized vasoconstriction and activation of coagulation, have been well described [4]. Correspondence: Francesca Raffaelli, Faculty of Medicine, Marche Polytechnic University, Via Tronto 10, Ancona, Italy. Tel: þ 39 071 2206058. Fax: þ 39 071 2206058. E-mail: raffi.3@virgilio.it (received 24 June 2010; revised 19 April 2011; accepted 16 May 2011)