Antihypertensive effects of inducible nitric oxide synthase inhibition in experimental pre-eclampsia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Upregulation of inducible nitric oxide synthase (iNOS) has been reported in both experimental and clinical hypertension. However, although pro-inflammatory cytokines that up-regulate iNOS contribute to pre-eclampsia, no previous study has tested the hypothesis that a selective iNOS inhibitor (1400W) could exert antihypertensive effects associated with decreased iNOS expression and nitrosative stress in pre-eclampsia. This study examined the effects of 1400W in the reduced uteroplacental perfusion pressure (RUPP) placental ischaemia animal model and in normal pregnant rats. Sham-operated and RUPP rats were treated with daily vehicle or 1mg/kg/day N-[3-(Aminomethyl) benzyl] acetamidine (1400W) subcutaneously for 5days. Plasma 8-isoprostane levels, aortic reactive oxygen species (ROS) levels and nicotinamide adenine dinucleotide phosphate (NADPH)-dependent ROS production were evaluated by ELISA, dihydroethidium fluorescence microscopy and lucigenin chemiluminescence respectively. Inducible nitric oxide synthase expression was assessed by western blotting analysis and aortic nitrotyrosine was evaluated by immunohistochemistry. Mean arterial blood pressure increased by similar to 30mmHg in RUPP rats, and 1400W attenuated this increase by similar to 50% (P<0.05). While RUPP increased plasma 8-isoprostane levels, aortic ROS levels, and NADPH-dependent ROS production (P<0.05), treatment with 1400W blunted these alterations (P<0.05). Moreover, while RUPP increased iNOS expression and aortic nitrotyrosine levels (P<0.05), treatment with 1400W blunted these alterations (P<0.05). These results clearly implicate iNOS in the hypertension associated with RUPP. Our findings may suggest that iNOS inhibitors could be clinically useful in the therapy of pre-eclampsia, especially in particular groups of patients genetically more prone to express higher levels of iNOS. This issue deserves further confirmation.171013001307Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Polymorphisms of the adiponectin gene in gestational hypertension and pre-eclampsia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Adiponectin is a hormone involved in energy homeostasis by regulating glucose and lipid metabolism. In addition, the adiponectin gene (ADIPOQ) has polymorphisms that can modulate the circulating concentration of adiponectin. Abnormal adiponectin levels have been associated with pre-eclampsia (PE); however, the influence of genetic polymorphisms on the development of hypertensive disorders of pregnancy is unclear. The aim of this study was to examine whether ADIPOQ polymorphisms are associated with gestational hypertension (GH) and/or PE. We studied 401 pregnant women: 161 healthy pregnant (HP), 113 pregnant with GH and 127 pregnant with PE. ADIPOQ polymorphisms - 11391G>A (rs17300539), - 11377C>G (rs266729), 45T>G (rs2241766) and 276G>T (rs1501299) were genotyped by allelic discrimination assays using real-time PCR. Haplotypes were inferred using the PHASE 2.1 program. We observed that the genotypic frequencies of the - 11377C>G polymorphism were different in PE compared with HP (P0.0125). No difference was observed when GH and HP groups were compared (both P>0.0125). In addition, we found no difference in genotype or allele distributions for the - 11391G>A, 45T>G and 276G>T polymorphisms when we compared GH or PE with HP (all P>0.0125). In conclusion, we found a modest association between the CG genotype of the - 11377C>G polymorphism and PE.282128132Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Haptoglobin polymorphism affects nitric oxide bioavailability in preeclampsia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Studies showed elevated cell-free hemoglobin (Hb) in preeclampsia (PE), and Hb reacts with nitric oxide (NO), decreasing its bioavailability. Haptoglobin (Hp) is a polymorphic protein (Hp1-1, Hp2-1 and Hp2-2) that binds Hb to form a complex that is removed from circulation, thus preventing Hb-driven oxidative stress and NO scavenging. Hp protein products differ in biochemical and biophysical properties, which reflects on the Hb-Hp complex clearance rate. We hypothesized that Hp phenotypes modulate NO bioavailability by influencing NO consumption in PE. We studied 92 PE subjects and 105 normal pregnant women (NP). Hp genotypes were determined using real-time PCR. To assess NO bioavailability, we measured plasma nitrite using an ozone-based chemiluminescence assay. Plasma Hb and Hp were assessed with commercial immunoassays. A NO consumption assay was used to measure NO consumption. We found no differences in Hp genotype frequencies between PE and NP groups. Hp genotypes had no effects on plasma heme levels, NO consumption and plasma nitrite in NP. However, in PE, Hp2-1 and Hp2-2 were associated with higher plasma heme levels (48 and 55% higher, respectively; P<0.05), increased NO consumption (42 and 44% more, respectively; P<0.05) and lower plasma nitrite (39% less for Hp2-2; P<0.05) compared with Hp1-1. These findings indicate that although Hp genotype does not affect the risk of PE, Hp1-1 genotype may exert a protective role in PE by reducing NO scavenging, whereas Hp2-1 and Hp2-2 further may aggravate PE by reducing NO bioavailability.276349354Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES