Nitric oxide in the human uterine cervix: Endogenous ripening factor

The human uterine cervix can produce nitric oxide (NO), a free radical with an ultra‐short half‐life. The release of NO changes during pregnancy and is increased in early nonviable pregnancies compared to normal uncomplicated pregnancies. This review concentrates on the role of NO release in cervical ripening in pregnant women. Also some suggestions on future aspects are discussed.     

High-risk human papillomavirus-induced expression of endothelial and inducible nitric oxide synthase in human uterine cervix

Introduction. Levels of nitric oxide metabolites are elevated in the cervical fluid of women with high-risk human papillomavirus (hrHPV). To elucidate the origin of this elevation we studied the cervical expression and localization of endothelial and inducible nitric oxide synthases (eNOS, iNOS) in women. Material and methods. Expression of eNOS and iNOS was studied by Western blotting in the uterine cervixes of 86 women with (n?=?41) and without (n?=?45) hrHPV infection. The localization of eNOS and iNOS in cervical cells was studied by immunohistochemistry in 32 randomly selected women. Results. Expression of eNOS and iNOS (in mean [95% CI] density units relative to actin) was higher in women with hrHPV versus those without (eNOS: 33.8 [22.5–45.1] versus 20.2 [6.1–34.3], P =?0.007; iNOS: 12.0 [7.1–16.9]) versus 5.6 [2.0–9.2], P?=?0.003). Smoking reduced 64% eNOS (P =?0.001) and 68% iNOS (P =?0.008) in women with hrHPV. Endothelial NOS was localized in the vascular endothelium, while iNOS was present in basal squamous epithelial cells. Low-grade histological lesions were accompanied by elevated expression of both eNOS and iNOS. Conclusions. High-risk HPV-associated elevation in cervical fluid nitric oxide metabolites results from both eNOS and iNOS stimulation. However, smoking seems to suppress this stimulation in hrHPV-infected women.     

Mechanical properties of the human uterine cervix: an in vivo study

Experimental results of in vivo measurements to characterize the mechanical behaviour of human uterine cervices are documented. Aspiration experiments were performed on eight uteri in vivo, before vaginal/abdominal hysterectomy, and four uteri were also tested ex vivo, approximately 1.5h after extraction. The reproducibility of the mechanical data from the in vivo aspiration experiments has been analysed. For an introduced "stiffness parameter" the organ specific SD is 22%, so that the proposed experimental procedure allows detections of 30% changes with respect to a reference value of the stiffness parameter. A comparison of in vivo and ex vivo data from the same organ has shown that: (i) the ex vivo mechanical response of the uterine cervix tissue does not differ considerably from that observed in vivo; (ii) some differences can be identified in tissue pre-conditioning with ex vivo showing a stronger history dependence with respect to in vivo; (iii) the differences in the time dependence of the mechanical response are not significant and might be masked by the variability of the measured data. This study represents a first step of a clinical application aiming at analysing the mechanical response of normal cervical tissue at different gestational ages, and identifying the mechanical properties that characterize pathologic conditions such as cervical insufficiency leading to preterm delivery.     

Nitric oxide indices in human septic shock

OBJECTIVES: To study the relation between nitrite, nitrate, nitrotyrosine, and nitrosothiols as NO indices in human septic shock. DESIGN: A prospective clinical study. SETTING: Intensive care units in a university hospital and a central county hospital. PATIENTS: Sixteen patients admitted for septic shock. Nine healthy volunteers served as controls. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients with septic shock had a hyperdynamic circulatory response and required infusion of at least two vasopressors to maintain systemic blood pressure. Four episodes of recurrent shock occurred in two patients. Heparinized plasma was collected once daily for analysis of NO indices. Peak plasma concentrations of nitrite + nitrate (NOx) were elevated in first episodes of septic shock; 144+/-39 microM vs. controls, 20+/-3 microM (p < .05). Peak plasma NOx concentrations in recurrent shocks were; 160+/-19 microM. Peak plasma concentrations of 3-nitrotyrosine (NT) were elevated in primary septic shock 102+/-19 pmol x mL(-1) vs. controls 14+/-6 pmol x mL(-1) (p < .05). Peak NT concentrations were 117+/-37 pmol x mL(-1) in recurrent septic shock. Peak plasma NT concentrations did not coincide with peak NOx concentrations in half of the episodes of septic shock. Plasma NT was elevated (59+/-15 pmol x mL(-1) vs. controls 14+/-6 pmol x mL(-1), p < .05) in patients with normal plasma NOx concentrations throughout septic shock. Plasma concentrations of nitrosothiols did not change during septic shock. CONCLUSIONS: Plasma concentrations of NOx and NT are elevated in primary episodes of septic shock and may also be elevated in secondary septic shock, but too few episodes of recurrent septic shock occurred to allow firm conclusions. Plasma concentrations of NT are elevated in patients with septic shock with normal plasma NOx concentrations, indicating that plasma concentrations of NOx may not always accurately reflect NO production. Reactive nitrogen species may be formed in septic shock, and measuring both NOx and NT may give a better indication of NO production in septic shock than NOx alone. Plasma levels of nitrosothiols did not change during septic shock.     

Nitric oxide and S-nitrosothiols in human blood

The hypothesis that endothelial-derived relaxing factor (EDRF) is nitric oxide has stimulated a wealth of research into the significance of this novel intriguing molecule. Given its short life, many storage forms of NO as well as targets have been postulated. Among these, a pool of derivatives of NO (S-nitrosothiols, RSNOs) covalently bound to SH groups of proteins and low molecular weight thiols (e.g., glutathione) have been identified in various biological systems. The importance of RSNOs results from the very similar biological actions exhibited by both NO and RSNOs in vivo as well as in vitro. In particular, it has been observed that in the bloodstream, these molecules are able to provoke vasodilatation with a consequent fall in blood pressure and an antithrombotic effect by inhibition of platelet aggregation. Many hypotheses have been postulated about the biochemical species and the mechanisms involved in these processes, but many aspects have not yet been clarified. In addition, some RSNOs have been recently proposed to be clinical parameters, whose levels may vary under some pathological conditions. The therapeutic utility of RSNOs as an alternative to classic NO donors has also been suggested.

Here, we provide a critical analysis of the main reports about the biochemical, physiological, pathological and therapeutic properties of RSNOs in the cardiovascular system. Particular attention is addressed to conflicting results and to discrepancies in the methodologies and models utilized. The numerous unanswered questions concerning the role of RSNOs in the control of vascular tone are discussed.     

Nitric oxide and malondialdehyde in human hypertension

Nitric oxide (NO), a multifunctional effector molecule that plays a central role in the maintenance of vascular homeostasis, regulates vascular tone and inhibits platelet and leukocyte adhesion to endothelial cells. NO status is related to the endothelial function. Patients with hypertension have lower levels of NO, increased free radical production, higher oxidative stress, augmented platelet aggregation, and a change in the arachidonic acid cascade metabolism, all leading to the acceleration of the atherosclerotic process. The study subjects included a group of 21 normotensive healthy subjects (8 males and 13 females) with a mean age of 39.2 +/- 1.8 years and a body mass index of 27.9 kg/m, and another group of 42 patients (19 males and 23 females) with untreated essential hypertension with a mean age of 47.6 +/- 1.7 years and a body mass index of 28.3 kg/m. Serum levels and urinary excretion of NO determined as combined nitrate/nitrite (NOx) and serum malondialdehyde (MDA) concentrations were measured in the 2 groups of subjects. The serum levels and 24-hour urinary excretion of NOx were significantly higher and the renal clearance of NO was lower in the normotensive group than in the hypertensive patients, indicating decreased NO status in hypertension. There was a negative correlation between serum NO levels and mean arterial pressure, suggesting that a decrease in NO availability is related to increase in blood pressure. Serum concentrations of MDA were higher in the hypertensive patients as compared with the normotensive individuals, suggesting increased oxidative stress in hypertensive patients. These results are in agreement with previous studies showing decreased NO and increased oxidative stress in hypertension. In conclusion, patients with essential hypertension as compared with normotensive individuals have lower NO status, which may contribute to the endothelial dysfunction in hypertension. Increased serum malondialdehyde in hypertensives suggests an association between increased oxidative stress with higher blood pressure.     

Nitric oxide contributes to estrogen-induced vasodilation of the ovine uterine circulation.

Estradiol-17beta (E2beta), a potent vasodilator, has its greatest effects on the uterine vasculature, blood flow (UBF) increasing > or = 10-fold. The mechanism(s) responsible for E2beta-induced vasodilation is unclear. We determined if nitric oxide (NO)-induced increases in cGMP modulate estrogen-induced increases in UBF, and if cyclooxygenase inhibition modifies E2beta responses. Nonpregnant (n = 15) and pregnant (n = 8) ewes had flow probes implanted on main uterine arteries and catheters in branches of the uterine vein and artery bilaterally for blood sampling and infusion of the NO synthase inhibitor L-nitro-arginine methyl ester (L-NAME), respectively. In nonpregnant ewes E2beta (1 microg/kg) caused parallel increases (P < 0.001) in UBF (15+/-3 to 130+/-16 ml/min) and uterine cGMP secretion (23+/-10 to 291+/-38 pmol/min); uterine venous cGMP also rose (4.98+/-1.4 to 9.43+/-3.2 pmol/ml; P < 0.001). Intra-arterial L-NAME partially inhibited increases in UBF dose-dependently (r = 0.66, n = 18, P < 0.003) while completely inhibiting cGMP secretion (P = 0.025). Indomethacin, 2 mg/kg intravenously, did not alter E2beta-induced responses. After E2beta-induced increases in UBF, intraarterial L-NAME partially decreased UBF dose dependently (r = 0.73, n = 46, P < 0.001) while inhibiting cGMP secretion (178+/-48 to 50+/-24 pmol/min; n = 5, P = 0.006); both were reversed by L-arginine. In pregnant ewes, E2beta increased UBF and venous cGMP (9.1+/-0.96 to 13.2+/-0.96 pmol/ml, P < 0.01); however, intraarterial L-NAME decreased basal cGMP secretion 66% (P = 0.02), but not UBF. Acute estrogen-induced increases in UBF are associated with NO-dependent increases in cGMP synthesis, but other mechanisms may also be involved. However, vasodilating prostanoids do not appear to be important. In ovine pregnancy NO is not essential for maintaining uteroplacental vasodilation.     

Nitric oxide in ischemic and reperfused human muscle

BACKGROUND: Biochemical events explaining the pathology of ischemia-reperfusion in the muscle are still debated. Nitric oxide (NO) has been postulated to be implicated in these phenomena, but the short half-life of this compound makes it difficult to measure. METHODS: In this paper, we used an amperometric solid-sate sensor to measure NO concentrations in frozen human muscles before, during and after a period of ischemia. We also measured cytochrome oxidase activity and malondialdehyde (MDA). RESULTS: NO increased during ischemia but it soon returned to normal values upon reperfusion. On the other hand, cytochrome oxidase that also decreased in ischemic muscle did not increase during the reperfusion and malondialdehyde only increased during reperfusion, indicating the occurrence of peroxidative reactions in this situation. CONCLUSIONS: NO is implicated in the ischemia/reperfusion pathology, but it is difficult to relate whether this is connected to cytochrome oxidase activity and malondialdehyde formation, also modified in this ischemia-reperfusion model.     

Nitric oxide suppresses the secretion of vascular endothelial growth factor and hepatocyte growth factor from human mesenchymal stem cells

The production of growth factors such as vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) by human bone marrow mesenchymal stem cells (MSCs) may play an important role in their paracrine effects on proliferation, differentiation, and protection. NO is produced during ischemia and may affect MSC function. However, it is unknown whether NO alters the production of VEGF and HGF from MSCs. To study this, human MSCs were stimulated to produce growth factors with TNF or LPS with and without various doses of NO donors or NOS inhibitors. We found that FK409, an NO donor, significantly suppressed the production of VEGF and HGF from human MSCs. Vascular endothelial growth factor in the supernatants of cells treated by 20 nM FK409 (497 +/- 19 pg/mL) was significantly lower compared with controls (625 +/- 34 pg/mL). Similarly, NO donor significantly suppressed the amount of HGF from controls (118 +/- 3 to 40 +/- 2 pg/mL) after treatment with 20 nM FK409. NO donor also abolished the augmentation of VEGF production induced by LPS. The amount of VEGF in the supernatant was 571 +/- 11 pg/mL when cells were treated with 20 nM FK409 and LPS (200 ng/mL), which was significantly lower than groups treated with LPS alone (941 +/- 30 pg/mL). This study constitutes an initial report regarding the effect of NO on human MSC growth factor production.     

PZ-peptidase activity in human uterine cervix in pregnancy at term.

PZ-peptidase (EC 3.4.--) was detected in human uterine cervix distributed in the soluble fraction after 100 000 x g centrifugation. Optimum pH for PZ-peptidase was observed to be pH 7.2--7.4, except for two of the preparations examined. PZ-peptidase activity was found to significantly increase in pregnancy at term as compared with that in a control group.     

Nitric oxide production contributes to the angiogenic properties of vascular endothelial growth factor in human endothelial cells.

Vascular endothelial growth factor (VEGF) is a regulator of vasculogenesis and angiogenesis. To investigate the role of nitric oxide (NO) in VEGF-induced proliferation and in vitro angiogenesis, human umbilical vein endothelial cells (HUVEC) were used. VEGF stimulated the growth of HUVEC in an NO-dependent manner. In addition, VEGF promoted the NO-dependent formation of network-like structures in HUVEC cultured in three dimensional (3D) collagen gels. Exposure of cells to VEGF led to a concentration-dependent increase in cGMP levels, an indicator of NO production, that was inhibited by nitro-L-arginine methyl ester. VEGF-stimulated NO production required activation of tyrosine kinases and increases in intracellular calcium, since tyrosine kinase inhibitors and calcium chelators attenuated VEGF-induced NO release. Moreover, two chemically distinct phosphoinositide 3 kinase (PI-3K) inhibitors attenuated NO release after VEGF stimulation. In addition, HUVEC incubated with VEGF for 24 h showed an increase in the amount of endothelial NO synthase (eNOS) protein and the release of NO. In summary, both short- and long-term exposure of human EC to VEGF stimulates the release of biologically active NO. While long-term exposure increases eNOS protein levels, short-term stimulation with VEGF promotes NO release through mechanisms involving tyrosine and PI-3K kinases, suggesting that NO mediates aspects of VEGF signaling required for EC proliferation and organization in vitro.     

Endocrine tumor of the uterine cervix

Endocrine tumor of the uterine cervix is rare, as only nine cases have been reported as patients who troubled by the ectopically endocrine hormone. Five of these patients afflicted by ectopic ACTH secretion which caused Cushing's syndrome, two suffered by insulin which resulted hypoglycemia, one distressed by PTH, and the other troubled by G-CSF. Seven of the nine patients were diagnosed histologically as small cell carcinoma, which was famous for neuroendocrine tumor, high incidence of vascular invasion and lymph node involvement, clinical behavior of hematogenously dissemination, and poor prognosis. Age of six patients was less than 50 years old, and metastatic tumor was confirmed in six of the nine patients.     

Lymphoepithelioma-like carcinoma of the uterine cervix

We describe two rare cervical tumors having morphologic features closely resembling those of the nasopharyngeal lymphoepithelioma. This entity has historically been classified as a subtype of squamous cell carcinoma, but after reviewing the literature and the two cases presented here, we propose that this tumor is a distinct carcinoma of the cervix that differs from squamous cell carcinoma in that it carries a more favorable prognosis, typically affects a younger population of women, is more prevalent in noncaucasian populations (especially those of Asian descent), and lacks a clearly defined association with infection due to human papilloma virus (HPV).     

原发性宫颈绒癌1例

患者女,34岁,因”阴道出血近1个月,HCG持续上升”入院.患者1个月前宫颈妊娠,清宫术后超声复查“子宫、双卵巢未见明显异常”.入院当日血βHCG 81 596 mIU/ml,超声见右侧卵巢大小32 mm×24 mm,内见26 mm×19 mm无回声区,且有细小分隔;左附件区见32 mm×36 mm无回声区,内见细小分隔,宫颈处见4 mm×3 mm等无回声区.     

Nitric oxide: therapeutic opportunities

Fifteen years after the discovery of nitric oxide as a biological mediator how close are new therapies? This article describes the roles of nitric oxide, illustrates how its discovery is altering the way in which certain established drugs are being used and reviews new therapeutic developments.     

Cytological diagnosis in dysplasia of the uterine cervix

Cytologic specimens presenting primarily superficial or intermediate dysplastic cells in the smear obtained by scraping the uterine cervix were defined as mild dysplasia, and those presenting primarily parabasal (or deep layer) dysplastic cells were defined as severe dysplasia. The rate of agreement of the above cytologic diagnosis to the histological diagnosis by target biopsy using the colposcope was 50% and 51% in mild and severe dysplasia, respectively. Specimens containing a few atypical cells which were strongly suspected to be malignant were classified as IIIb. From this group, malignant lesions were found in 48% and severe dysplasia in 35%.     

Nitric oxide regulates the calcium current in isolated human atrial myocytes.

Cardiac Ca2+ current (ICa) was shown to be regulated by cGMP in a number of different species. Recently, we found that the NO-donor SIN-1 (3-morpholino-sydnonimine) exerts a dual regulation of ICa in frog ventricular myocytes via an accumulation of cGMP. To examine whether NO also regulates Ca2+ channels in human heart, we investigated the effects of SIN-1 on ICa in isolated human atrial myocytes. An extracellular application of SIN-1 produced a profound stimulatory effect on basal ICa at concentrations > 1 pM. Indeed, 10 pM SIN-1 induced a approximately 35% increase in ICa. The stimulatory effect of SIN-1 was maximal at 1 nM (approximately 2-fold increase in ICa) and was comparable with the effect of a saturating concentration (1 microM) of isoprenaline, a beta-adrenergic agonist. Increasing the concentration of SIN-1 to 1-100 microM reduced the stimulatory effect in two thirds of the cells. The stimulatory effect of SIN-1 was not mimicked by SIN-1C, the cleavage product of SIN-1 produced after liberation of NO. This suggests that NO mediates the effects of SIN-1 on ICa. Because, in frog heart, the stimulatory effect of SIN-1 on ICa was found to be due to cGMP-induced inhibition of cGMP-inhibited phosphodiesterase (cGI-PDE), we compared the effects of SIN-1 and milrinone, a cGI-PDE selective inhibitor, on ICa in human. Milrinone (10 microM) induced a strong stimulation of ICa (approximately 150%), demonstrating that cGI-PDE controls the amplitude of basal ICa in this tissue. In the presence of milrinone, SIN-1 (0.1-1 nM) had no stimulatory effect on ICa, suggesting that the effects of SIN-1 and MIL were not additive. We conclude that NO may stimulate ICa in human atrial myocytes via inhibition of the cGI-PDE.