Association of endothelial nitric oxide synthase gene G894T polymorphism and serum nitric oxide levels in patients with preeclampsia and gestational hypertension

Objective: Pregnancy-induced hypertension is one of the most important cause of maternal-fetal morbidity and mortality. Pregnancy-related hypertensive disorders are usually associated with diminished nitric oxide (NO) levels. We aimed to evaluate the role of serum NO levels and eNOS gene G894T polymorphism on hypertensive disorders of pregnancy.

Methods: Eighty patients with gestational hypertension or preeclampsia, and 80 healthy pregnants were enrolled to analyze serum NO levels and G894T polymorphism of the eNOS gene. NO level was analyzed by high-performance liquid chromatography (HPLC) method. The G894T polymorphism of the eNOS gene was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).

Results: There was no significant difference between groups in terms of G894T/eNOS genotype and allele frequencies (p?>?0.05). Serum NO levels were significantly lower in the patients group. In the control group, subjects with thymine-thymine (TT) genotype had significantly lower NO levels when compared to subjects with guanine-guanine (GG) or guanine-thymine (GT) genotype (p?Conclusions: We failed to demonstrate an association between eNOS gene G894T polymorphism and serum NO levels in patients with pregnancy-induced hypertensive disorders. We established a relation between pregnancy-induced hypertension and low NO levels.     

Molecular cloning of ovine endothelial nitric oxide synthase and expression in COS-7 cells

While studies of human and bovine endothelial nitric oxide synthase (eNOS) demonstrate activation by Ca(2+)/calmodulin, recent progress demonstrates that eNOS phosphorylation can alter sensitivity to intracellular free calcium ([Ca(2+)](i)). The sheep, however, is widely used as a model for cardiovascular adaptation to pregnancy and ovine uterine artery endothelial cell (UAEC) eNOS undergoes pregnancy-specific (P) enhancement of activity associated with increased Ca(2+) and protein kinase signaling in response to a number of agonists, including adenosine triphosphate (ATP). The degree of homology between the ovine and human full-length cDNAs was not previously known and yet is necessary to determine the validity in using an ovine model to study human physiology. The objectives of this study were to isolate and validate the clone of ovine eNOS cDNA and investigate ovine eNOS activation when expressed in COS-7 cells. The ovine eNOS cDNA has high homology to published human and bovine sequences and shares identity with the bovine amino acid sequence. When ovine eNOS was transiently expressed in COS-7 cells (COS-7/oeNOS), A23187 increased specific catalytic activity in a dose- and time-dependent manner. A23187-stimulated activation of eNOS was, however, also accompanied by phosphorylation of eNOS S1179 and dephosphorylation of T497, demonstrating that an increase in [Ca(2+)](i) may not be the sole mechanism of activation. The physiologic relevance of this was further underscored by the finding that ATP dose-dependently increased peak [Ca(2+)](i) and eNOS activity in COS-7/oeNOS, but also increased eNOS p-S1179 and decreased p-T497. This finding was similar to those in ovine P-UAEC treated with the Ca(2+)-mobilizing agonist ATP, wherein activation of eNOS was again concomitant with a rise p-S1179 as well as a slight decrease in p-T497. In conclusion, we describe the full-length ovine eNOS cDNA sequence and show that both physiologic and nonphysiologic calcium-mobilizing agents, which activate ovine eNOS in COS-7 and P-UAEC, do so in association with changes in eNOS phosphorylation. Given this information we can now begin to dissect the relationship between Ca(2+) elevation and specific phosphorylation events in eNOS activation in the ovine model, and thereby gain insight into the possible basis for pregnancy-related dysfunction.     

Reduced endothelial nitric oxide synthase activity and concentration in fetal umbilical veins from maternal cigarette smokers

OBJECTIVE: This study aimed to investigate the effect of maternal cigarette smoking on endothelial nitric oxide synthase (eNOS) activity and concentration in the fetal umbilical vein, and subsequently, to relate the findings to the size of the newborn. STUDY DESIGN: Forty-four nonsmoking and 30 smoking women were included in the study. Umbilical vein endothelial cells were isolated immediately after delivery. The eNOS activity was determined in the samples by the conversion of (14)C-L-arginine to (14)C-L-citrulline, and the eNOS concentration was determined by a human eNOS immunoassay. RESULTS: Newborns of smokers had a lower weight (P=.014) and a smaller head circumference (P=.002) than those newborns of nonsmokers. The eNOS activity in fetal umbilical veins exposed to maternal smoking was 40% lower (P=.006), and the eNOS concentration 32% lower (P=.053) in newborns of smokers than in nonsmokers. CONCLUSION: The findings suggest that maternal smoking reduces nitric oxide production in the fetal circulation. This may contribute to retarded fetal growth caused by the subsequent endothelial dysfunction with reduction of dilatory capacity of the vessels.     

尿皮素对体外培养的人脐静脉内皮细胞一氧化氮及一氧化氮合酶的影响

目的:通过检测尿皮素(UCN)对人脐静脉内皮细胞(HUVEC)一氧化氮(NO)生成及一氧化氮合酶(NOS)表达的影响,探讨UCN调节胎儿-胎盘血管张力的分子机制。方法:在离体培养的HUVEC中加入不同浓度的UCN(0、0.1、1、10nmol/L)、10nmol/L促肾上腺皮质激素释放激素(CRH)及向以上各组UCN/CRH同时加α-helical-CRH进行体外培养,用硝酸还原酶法检测细胞上清液中NO的水平,蛋白印迹法检测内皮型一氧化氮合酶(eNOS)和诱导型一氧化氮合酶(iNOS)蛋白表达水平的变化。结果:在与UCN共同培养4~8h后,HUVEC细胞上清液中NO水平呈时间和剂量依赖性变化,随着培养时间的延长,UCN浓度增加,NO水平逐渐升高;UCN组HUVEC iNOS表达水平比对照组明显升高(P<0.05),且呈浓度依赖性升高。而各组eNOS表达水平与对照组比较无明显变化(P>0.05)。UCN/CRH α-helical-CRH组HUVEC上清液中NO水平和HU-VEC iNOS表达水平与对照组比较无明显变化,差异无统计学意义(P>0.05),与相同浓度UCN/CRH组比较NO水平和iNOS蛋白表达水平明显降低,差异有统计学意义(P<0.05)。结论:UCN可促HUVEC合成及释放NO,NO生成增多与UCN通过促进肾上腺皮质激素释放激素2β受体(CRH-R2β)正相调节iNOS蛋白表达有关,这可能是UCN调节胎儿-胎盘血管张力的分子机制之一。     

Localized increase in nitric oxide production and the expression of nitric oxide synthase isoforms in rat uterus with experimental intrauterine infection.

OBJECTIVE: We recently reported that nitric oxide was associated with increased mortality among pregnant rats with intrauterine infection. In our current study we investigated the expression of different isoforms of nitric oxide synthases and nitric oxide in the nonpregnant rat uterus with experimental intrauterine infection. STUDY DESIGN: Pathogenic Escherichia coli was inoculated into the uterine lumen of ovariectomized rats. Animals were killed after inoculation, and uterine horns were collected for assessing nitric oxide production with high-performance liquid chromatography and nitric oxide synthase (type II and type III) protein expression with Western immunoblotting and immunofluorescence methods. RESULTS: (1) Nitric oxide production increased in the infected uterine horn in a time-dependent manner after intrauterine infection but did not increase in the uninfected horn. (2) Nitric oxide synthase type III protein contents did not show a difference between infected and uninfected horns, and type III nitric oxide synthase was expressed by the epithelial cells and smooth muscle cells. (3) Type II nitric oxide synthase was abundantly expressed in infected horns but was not expressed in uninfected horns. Immunofluorescence data indicated that macrophages and natural killer cells, located in the endometrial layer clustering around epithelial cells, expressed type II protein. CONCLUSION: We suggest that localized increase in type II nitric oxide synthase expression and nitric oxide production occurs in response to intrauterine infection and that the nitric oxide system may play a role in host response to restrict the infection.     

血管内皮生长因子与妊娠高血压综合征发病及一氧化氮的关系

目的　探讨血管内皮生长因子（VEGF）在妊娠高血压综合征（妊高征）发病中的作用,及其与一氧化氮（NO）的关系。方法　选择妊高征患者(妊高征组)41例,其中轻度妊高征12例,中度妊高征13例,重度妊高征16例;选择同期正常晚期妊娠妇女20例为对照组。采用酶联免疫吸附法测定两组孕妇血清VEGF水平,用硝酸盐还原酶法测定两组胎盘组织NO浓度变化。结果　（1）妊高征组血清VEGF水平明显低于对照组,轻度妊高征患者血清VEGF水平与对照组比较,差异无显著性,中、重度妊高征患者血清VEGF水平分别为（23.1±4.1）ng/L、（14.8±3.9）ng/L,明显低于对照组。（2）妊高征组胎盘组织中NO浓度较对照组明显降低,轻度妊高征患者胎盘组织NO浓度与对照组比较,差异无显著性,中、重度妊高征患者胎盘组织NO浓度分别为（9.1±2.1）μmol/g、(5.6±1.8)μmol/g,均明显低于对照组。（3）血清VEGF水平与胎盘组织NO浓度呈显著正相关（r=0.65,P<0.01）。结论　妊高征患者血清中VEGF水平降低,胎盘组织中NO浓度下降,可能在妊高征的发病中起一定作用。     

Effect of antenatal dexamethasone on the expression of endothelial nitric oxide synthase in the lungs of postnatal pups

Activities of endothelial nitric oxide synthase (eNOS) are developmentally regulated and its presence at birth may play a role in the transition of cardiopulmonary circulation. Antenatal dexamethasone (Dex) therapy accelerates fetal lung maturation. We speculate that Dex therapy may enhance pulmonary eNOS protein expression in the newborn. This article examines whether antenatal Dex therapy affected the expression of eNOS in the lungs of rat pups in the postnatal period. Time-dated pregnant Wistar rats were subjected to 2 doses of Dex (0.8 mg/kg, intramuscularly, daily) or equivalent volume of normal saline at the 18th and 19th gestational day and delivered naturally. The newborn pups were randomly assigned to 4 groups by age: days 1, 3, 5, and 7. After homogenization, abundance of eNOS protein in lungs was determined by Western blot analysis. There were 7 dams in each group. Mean body weights of the pups in the Dex group were lighter than those in the control at birth and remained stunted up to day 7 (5.68+/-0.47 g v 6.34+/-0.47 g, P <.01). However, there were no differences in wet lung weights and lung/body weight ratios between both groups in the study period. Abundance of eNOS protein expression decreased in both the control and Dex groups (P < .01). Pups that received antenatal Dex had 39% more in abundance of eNOS protein expression in lungs when compared to the control on day 1 (P < .05) but there were no differences between both groups from day 3 to 7. We conclude that antenatal Dex therapy enhances the abundance of eNOS protein expression in the lung at birth and could be a factor in improving respiratory functions in infants who received antenatal steroid therapy.     

Amniotic levels of nitric oxide and vascular endothelial growth factor in pregnancy with subsequent intrauterine fetal death

OBJECTIVE: Nitric oxide (NO) and vascular endothelial growth factor (VEGF) regulate angiogenesis and seem involved in the early stages of placentation. If angiogenesis is reduced, this may lead to poor placentation and fetal death. This study was aimed to determine whether VEGF and NO are associated to subsequent fetal death. STUDY DESIGN: We retrospectively assessed NO and VEGF on midtrimetster amniotic fluid from seven women who had subsequently had intrauterine fetal death before 20 weeks, and compared the results with those of 14 controls matched for age and gestation. All women had undergone amniocentesis for maternal age. All were at 16 weeks of gestation. None had shown chromosomal abnormalities. Results (mean+/-S.D.) were tested for statistics with Student's t-test with significance at P<0.05. RESULTS: Women with subsequent fetal death had both amniotic NO and VEGF lower than women with normal pregnancy (NO 3.28+/-1.20 microg/mg creatinine versus 6.02+/-1.57 microg/mg creatinine, P<0.05; VEGF 210.10+/-69.55 pg/ml versus 255.05+/-88.66 pg/ml). CONCLUSIONS: An early reduction of both NO and VEGF may be responsible of an impaired placental vascular development and endothelial regulation that may lead to fetal death.     

Polymorphisms of the endothelial nitric oxide synthase gene in women with vulvar cancer

Objective. Nitric oxide (NO) is involved in angiogenesis and tumor growth. We attempted to establish an association between two polymorphisms of the endothelial nitric oxide synthase (NOS3) gene and vulvar cancer.Methods. We used peripheral vanous blood sampling, DNA extraction, and polymerase chain reaction (PCR) and pyrosequencing to genotype 68 women with vulvar cancer and 227 healthy Caucasian women for the presence of the intron 4 27-bp-repeat [NOS3*A] and exon 7 Glu298Asp polymorphisms.Results. The presence of a polymorphic NOS3*A allele (26.2% vs. 24.6%; OR: 1.01; 95% CI: 0.6–2.0; P = 0.9) or a polymorphic NOS3 exon 7 Glu298Asp allele (41.2% vs. 53.7%; OR: 0.6; 95% CI: 0.3–1.0; P = 0.09) was not associated with vulvar cancer. Within the vulvar cancer group, the presence of a polymorphic NOS3*A or a polymorphic NOS3 exon 7 Glu298Asp allele was not associated with clinico-pathological parameters such as advanced tumor stage, groin lymph node involvement, tumor grading, and age at diagnosis. Survival analysis demonstrated that the presence of a polymorphic NOS3*A allele was associated with a significantly reduced disease-free survival time (P = 0.03), whereas the presence of the polymorphic NOS3 exon 7 Glu298Asp allele was not associated with disease-free survival (P = 0.5).Conclusions. We are the first to report on NOS3 polymorphisms in vulvar cancer. We found that allelic variation within intron 4, but not within exon 7 of NOS3, influences the length of disease-free survival, but not the biological phenotype of vulvar cancer.