Local Nitric Oxide Production Research Articles

Decreased Hippocampal Neurogenesis in Aged Male Wistar Rats Is Not Associated with Memory Acquisition in a Water Maze.

Brain aging is associated with a progressive decrease in learning abilities, memory, attention, decision making, and sensory perception. Age-related cognitive disturbances may be related to a decrease in the functional capacities of the hippocampus. This brain region is essential for learning and memory, and the lifelong neurogenesis occurring in the subgranular zone of the dentate gyrus may be a key event mediating the mnemonic functions of the hippocampus. In the present study, we investigated whether age-related changes in hippocampal neurogenesis are associated with learning and memory disturbances. Four- and 24-month-old rats were trained to find a hidden platform in a water maze. Though the older group showed higher latency to search the platform as compared to the younger group, both groups learned the task. However, the density of proliferating (PCNA-positive), differentiating (Dcx-positive), and new neurons (pre-labeled BrdU-positive) was significantly lower in the hippocampus of aged rats as compared to young ones. This inhibition of neurogenesis could be related to increased local production of nitric oxide since the density of neurons expressing neuronal NO-synthase was higher in the aged hippocampus. Thus, we can suggest that an age-related decrease in neurogenesis is not directly associated with place learning in aged rats.

How do we kNOw the individual contribution of eNOS and nNOS for cerebral blood flow regulation?

How do we kNOw the individual contribution of eNOS and nNOS for cerebral blood flow regulation?

Simvastatin Posttreatment Controls Inflammation and Improves Bacterial Clearance in Experimental Sepsis.

Sepsis is characterized by a life-threatening organ dysfunction caused by an unbalanced host response to microbe infection that can lead to death. Besides being currently the leading cause of death in intensive care units worldwide, sepsis can also induce long-term consequences among survivors, such as cognitive impairment. Statins (lipid-lowering drugs widely used to treat dyslipidemia) have been shown to possess pleiotropic anti-inflammatory and antimicrobial effects. These drugs act inhibiting 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, an enzyme that catalyzes the conversion of HMG-CoA to mevalonate, the limiting step in cholesterol biosynthesis. In this work, we evaluated the therapeutic effects of simvastatin in an animal model of sepsis. In previous study from our group, statin pretreatment avoided cognitive damage and neuroinflammation in sepsis survivors. Herein, we focused on acute inflammation where sepsis was induced by cecal ligation and puncture (CLP), and the animals were treated with simvastatin (2 mg/kg) 6 h after surgery. We measured plasma biochemical markers of organ dysfunction, cell migration, cell activation, bacterial elimination, production of nitric oxide 24 h after CLP, survival rate for 7 days, and cognitive impairment 15 days after CLP. One single administration of simvastatin 6 h after CLP was able to prevent both liver and kidney dysfunction. In addition, this drug decreased cell accumulation in the peritoneum as well as the levels of TNF-α, MIF, IL-6, and IL-1β. Simvastatin diminished the number of bacterial colony forming units (CFU) and increased the production of nitric oxide production in the peritoneum. Simvastatin treatment increased survival for the first 24 h, but it did not alter survival rate at the end of 7 days. Our results showed that posttreatment with simvastatin hampered organ dysfunction, increased local production of nitric oxide, improved bacterial clearance, and modulated inflammation in a relevant model of sepsis.

The Use of Vasoactive Drugs in the Treatment of Male Erectile Dysfunction: Current Concepts.

It is widely accepted that disorders of the male (uro)genital tract, such as erectile dysfunction (ED) and benign diseases of the prostate (lower urinary tract symptomatology or benign prostatic hyperplasia), can be approached therapeutically by influencing the function of both the vascular and non-vascular smooth muscle of the penile erectile tissue or the transition zone/periurethral region of the prostate, respectively. As a result of the discovery of nitric oxide (NO) and cyclic guanosine monophosphate (GMP) as central mediators of penile smooth muscle relaxation, the use of drugs known to increase the local production of NO and/or elevate the intracellular level of the second messenger cyclic GMP have attracted broad attention in the treatment of ED of various etiologies. Specifically, the introduction of vasoactive drugs, including orally active inhibitors of the cyclic GMP-specific phosphodiesterase (PDE) 5, has offered great advantage in the pharmacotherapy of ED and other diseases of the genitourinary tract. These drugs have been proven efficacious with a fast on-set of action and an improved profile of side-effects. This review summarizes current strategies for the treatment of ED utilizing the application of vasoactive drugs via the oral, transurethral, topical, or self-injection route.

Pharmacological Screening Identifies SHK242 and SHK277 as Novel Arginase Inhibitors with Efficacy against Allergen-Induced Airway Narrowing In Vitro and In Vivo.

Arginase is a potential target for asthma treatment. However, there are currently no arginase inhibitors available for clinical use. Here, a novel class of arginase inhibitors was synthesized, and their efficacy was pharmacologically evaluated. The reference compound 2(S)-amino-6-boronohexanoic acid (ABH) and >200 novel arginase inhibitors were tested for their ability to inhibit recombinant human arginase 1 and 2 in vitro. The most promising compounds were separated as enantiomers. Enantiomer pairs SHK242 and SHK243, and SHK277 and SHK278 were tested for functional efficacy by measuring their effect on allergen-induced airway narrowing in lung slices of ovalbumin-sensitized guinea pigs ex vivo. A guinea pig model of acute allergic asthma was used to examine the effect of the most efficacious enantiopure arginase inhibitors on allergen-induced airway hyper-responsiveness (AHR), early and late asthmatic reactions (EAR and LAR), and airway inflammation in vivo. The novel compounds were efficacious in inhibiting arginase 1 and 2 in vitro. The enantiopure SHK242 and SHK277 fully inhibited arginase activity, with IC50 values of 3.4 and 10.5 μM for arginase 1 and 2.9 and 4.0 µM for arginase 2, respectively. Treatment of slices with ABH or novel compounds resulted in decreased ovalbumin-induced airway narrowing compared with control, explained by increased local nitric oxide production in the airway. In vivo, ABH, SHK242, and SHK277 protected against allergen-induced EAR and LAR but not against AHR or lung inflammation. We have identified promising novel arginase inhibitors for the potential treatment of allergic asthma that were able to protect against allergen-induced early and late asthmatic reactions. SIGNIFICANCE STATEMENT: Arginase is a potential drug target for asthma treatment, but currently there are no arginase inhibitors available for clinical use. We have identified promising novel arginase inhibitors for the potential treatment of allergic asthma that were able to protect against allergen-induced early and late asthmatic reactions. Our new inhibitors show protective effects in reducing airway narrowing in response to allergens and reductions in the early and late asthmatic response.

Genotoxic and anti-proliferative effects of aminoguanidine on gamma-irradiated MCF-7 breast cancer cells.

The intracellular production of nitric oxide is studied as a relevant phenomenon in exposure to ionizing radiation. There is evidence of local nitric oxide production in solid tumours. Its effects were observed on the relationship between their presence with tumor progression, linked to the emergence of potential genotoxic or cytotoxic damage, or loss of proliferative capacities of tumour cells. The study evaluated the effects of the administration of aminoguanidine, a selective inhibitor of an isoform of nitric oxide synthase on the frequency of genotoxic damage, loss of clonogenic potential, induction of cytotoxicity and nitrite production after exposure to ionizing radiation in radiotherapeutic doses. Human breast tumor (MCF7) cells were treated with aminoguanidine (1 or 2 mM) and irradiated by gamma radiation at doses between 0.5 and 8Gy. The study used a well stablished technique with some modifications for evaluation of genotoxic damage by frequency of micronuclei in binucleated cells. In cultures treated with 1 mM, we observed increased cytotoxicity and genotoxicity, and reduction of the clonogenic potential of the colonies. Alternatively, 2 mM aminoguanidine produced the opposite effect, apparently protecting cultures from the effects of exposures. The experiments suggested that the administration of aminoguanidine may reduce the in vitro radiossensitivity of tumors due to the increase of the frequency of genotoxic damage.

Abstract 265: Oral Nitrite Supplementation Improves Rates of Wound Healing in Diabetic Mice

Introduction: Nitric oxide (NO) is required for cutaneous wound healing. Impaired diabetic wound healing has been linked to a deficiency in local NO production and can be enhanced with NO delivery. NO is a short-lived, highly reactive molecule and local delivery is complicated by these properties. An alternate source of NO can be achieved through the ability of nitrite reductases to convert the stable NO end-product, nitrite, back to NO. We have previously demonstrated that skin and wound edge express high levels of xanthine oxidoreductase (XOR). XOR is a strong nitrite reductase. We hypothesize that dietary nitrite supplementation will improve wound healing in diabetic mice. Methods: Db/db mice (N>8/group) were pretreated for 1 week with sodium nitrite supplemented drinking water (50 mg/L), nitrite-free chow, or standard chow. Additionally, nitrite supplemented mice were gavaged with nitrite supplemented water (0.2 ml) every other day for the duration of the experiment. A 1 cm 2 excisional wound was created on the back of each mouse. Wounds were photographed every other day until closure and wound areas calculated with ImageJ and compared with ANOVA and Kaplan Meier. Results: Time to complete healing was significantly different between nitrite supplemented (NS), nitrite depleted (ND), and control mice (18.9±0.7, 21.6±3.3, and 23±3.5 days, respectively, P = 0.035). NS mice reached 75% and 100% healed faster than ND or control mice (P = .009 and P = .042, respectively) [Figure]. Initial wound expansion on day 2 was decreased in NS mice compared to ND mice. XOR activity was increased in wounds compared to skin but similar between all treatment groups. Conclusion: Nitric oxide is a critical component of wound healing. Oral systemic nitrite supplementation improves diabetic wound healing in mice. Dietary nitrite may be an inexpensive and safe method of augmenting NO production through wound XOR expression to improve wound repair.

Cellular mechanisms involved in induction of selective degeneration of orexin neurons in the hypothalamus

Narcolepsy is a kind of sleep disorder featured by selective loss of orexin neurons in the lateral hypothalamus. Several lines of evidence, including association with specific HLA haplotypes, gene polymorphism in T cell receptor and detection of autoantibodies in a subpopulation of patients, suggest that autoimmune responses play an important role in the pathogenesis of this disorder. Potential relationship with influenza virus infection has also been a matter of interest. However, these events may not be able to explain all cases of narcolepsy. Based on the structural features of orexin, in addition to the findings on the characteristics of orexin neurons obtained from studies in organotypic hypothalamic slice cultures, we proposed novel mechanisms potentially involved in selective degeneration of orexin neurons. Increase in local production of nitric oxide induced by several life style-related conditions such as shortage of sleep and intake of high fat diet leads to inactivation of protein disulfide isomerase. Consequently, abnormal aggregates of orexin and/or its precursor that possess two intra-molecular disulfide bonds accumulate within orexin neurons. In addition to the increase in endoplasmic reticulum stress, accumulation of orexin as abnormal aggregates leads to increased excitability of orexin neurons by shutdown of feedback inhibition resulting from deficits in orexin release. These mechanisms may provide a clue to understand the pathogenic mechanisms of various neurological and psychiatric disorders accompanied by a decrease of orexin.

Rapid versus slow ascending vasodilatation: intercellular conduction versus flow-mediated signalling with tetanic versus rhythmic muscle contractions.

In response to exercise, vasodilatation ascends from downstream arterioles into upstream feed arteries (FAs). We hypothesized that the signalling events underlying ascending vasodilatation variy with the intensity and duration of skeletal muscle contraction. In the gluteus maximus muscle of C57BL/6 mice, brief tetanic contraction evoked rapid onset vasodilatation (ROV) (<1s) throughout the resistance network. Selective damage to endothelium midway between FAs and primary arterioles eliminated ROV only in FAs. Blocking SKCa and IKCa channels attenuated ROV, implicating hyperpolarization as the underlying signal. During rhythmic twitch contractions, slow onset vasodilatation (10-15s) in FAs remained intact following loss of ROV and was eliminated following nitric oxide synthase inhibition. Tetanic contraction initiates hyperpolarization that conducts along endothelium into FAs. Rhythmic twitch contractions stimulate FA endothelium to release nitric oxide in response to elevated shear stress secondary to metabolic dilatation of arterioles. Complementary endothelial signalling pathways for ascending vasodilatation ensure increased oxygen delivery to active skeletal muscle. In response to exercise, vasodilatation initiated within the microcirculation of skeletal muscle ascends the resistance network into upstream feed arteries (FAs) located external to the tissue. Ascending vasodilatation (AVD) is essential for reducing FA resistance that otherwise restricts blood flow into the microcirculation. In the present study, we tested the hypothesis that signalling events underlying AVD vary with the intensity and duration of muscle contraction. In the gluteus maximus muscle of anaesthetized male C57BL/6 mice (aged 3-4months), brief tetanic contraction (100Hz for 500ms) evoked rapid onset vasodilatation (ROV) in FAs that peaked within 4s. By contrast, during rhythmic twitch contractions (4Hz), slow onset vasodilatation (SOV) of FAs began after ∼10s and plateaued within 30s. Selectively damaging the endothelium with light-dye treatment midway between a FA and its primary arteriole eliminated ROV in the FA along with conducted vasodilatation of the FA initiated on the arteriole using ACh microiontophoresis. Superfusion of SKCa and IKCa channel blockers UCL 1684+TRAM 34 attenuated ROV, implicating endothelial hyperpolarization as the underlying signal. Nevertheless, the SOV of FAs during rhythmic contractions persisted until inhibition of nitric oxide synthase with Nω -nitro-l-arginine methyl ester. Thus, ROV of FAs reflects hyperpolarization of downstream arterioles that conducts along the endothelium into proximal FAs. By contrast, SOV of FAs reflects the local production of nitric oxide by the endothelium in response to luminal shear stress, which increases secondary to arteriolar dilatation downstream. Thus, AVD ensures increased oxygen delivery to active muscle fibres by reducing upstream resistance via complementary signalling pathways that reflect the intensity and duration of muscle contraction.

NOS-interacting protein (NOSIP) is increased in the colon of patients with Hirschsprungs's disease

PurposeHirschsprung's associated enterocolitis (HAEC) is the most common cause of morbidity and mortality in Hirschsprung's disease (HSCR). Nitric oxide (NO) mediates intestinal homoeostasis and is inhibited by NOSIP, a modulator of NO production. We designed this study to investigate the expression of NOSIP in the colon of patients with HSCR. MethodsWe investigated NOSIP, endothelial NO synthase, and neuronal NO synthase expression in both the aganglionic and ganglionic regions of HSCR patients (n=10) versus normal control colon (n=10). Protein distribution was assessed by using immunofluorescence and confocal microscopy. Gene and protein expression were quantified using quantitative real-time polymerase chain reaction (qPCR), Western blot analysis, and densitometry. Main resultsqPCR and Western blot analysis demonstrate that NOSIP was significantly increased in the aganglionic and ganglionic colon compared to controls (p<0.05). Confocal microscopy revealed a markedly increased expression of NOSIP in the colon epithelium of patients with HSCR compared to controls. ConclusionTo our knowledge, we demonstrate for the first time the expression of NOSIP in the human colon. While NOSIP expression was increased in HSCR vs. non-HSCR patients, no significant difference was observed in patients with HAEC. The increased expression of NOSIP in the aganglionic and ganglionic bowel of HSCR may contribute to the development of enterocolitis by inhibiting local NO production in patients with Hirschsprung's disease. Level of evidenceII

Nitric oxide promotes GABA release by activating a voltage-independent Ca2+ influx pathway in retinal amacrine cells.

Retinal amacrine cells express nitric oxide (NO) synthase and produce NO, making NO available to regulate the function of amacrine cells. Here we test the hypothesis that NO can alter the GABAergic synaptic output of amacrine cells. We investigate this using whole cell voltage clamp recordings and Ca2+ imaging of cultured chick retinal amacrine cells. When recording from amacrine cells receiving synaptic input from other amacrine cells, we find that NO increases GABAergic spontaneous postsynaptic current (sPSC) frequency. This increase in sPSC frequency does not require the canonical NO receptor, soluble guanylate cyclase, or presynaptic action potentials. However, removal of extracellular Ca2+ and buffering of cytosolic Ca2+ both inhibit the response to NO. In Ca2+ imaging experiments, we confirm that NO increases cytosolic Ca2+ in amacrine cell processes by activating a Ca2+ influx pathway. Neither the increase in sPSC frequency nor the cytosolic Ca2+ elevations are dependent upon Ca2+ release from stores. NO also enhances evoked GABAergic responses. Because voltage-gated Ca2+ channel function is not altered by NO, the increased evoked response is likely due to the combined effect of voltage-dependent Ca2+ influx adding to the NO-dependent, voltage-independent, Ca2+ influx. Insight into the identity of the Ca2+ influx pathway is provided by the transient receptor potential canonical (TRPC) channel inhibitor clemizole, which prevents the NO-dependent increase in sPSC frequency and cytosolic Ca2+ elevations. These data suggest that NO production in the inner retina will enhance Ca2+-dependent GABA release from amacrine cells by activating TRPC channel(s).NEW & NOTEWORTHY Our research provides evidence that nitric oxide (NO) promotes GABAergic output from retinal amacrine cells by activating a likely transient receptor potential canonical-mediated Ca2+ influx pathway. This NO-dependent mechanism promoting GABA release can be voltage independent, suggesting that, in the retina, local NO production can bypass the formal retinal circuitry and increase local inhibition.

Lymphatic endothelial cells efferent to inflamed joints produce iNOS and inhibit lymphatic vessel contraction and drainage in TNF-induced arthritis in mice.

BackgroundIn this study, we sought to determine the cellular source of inducible nitric oxide synthase (iNOS) induced in lymphatic endothelial cells (LECs) in response to tumor necrosis factor (TNF), the effects of iNOS on lymphatic smooth muscle cell (LSMC) function and on the development of arthritis in TNF-transgenic (TNF-Tg) mice, and whether iNOS inhibitors improve lymphatic function and reduce joint destruction in inflammatory erosive arthritis.MethodsWe used quantitative polymerase chain reactions, immunohistochemistry, histology, and near-infrared imaging to examine (1) iNOS expression in podoplanin + LECs and lymphatic vessels from wild-type (WT) and TNF-Tg mice, (2) iNOS induction by TNF in WT LECs, (3) the effects of iNOS inhibitors on expression of functional muscle genes in LSMCs, and (4) the effects of iNOS inhibitors on lymphatic vessel contraction and drainage, as well as the severity of arthritis, in TNF-Tg mice.ResultsLECs from TNF-Tg mice had eight fold higher iNOS messenger RNA levels than WT cells, and iNOS expression was confirmed immunohistochemically in podoplanin + LECs in lymphatic vessels from inflamed joints. TNF (0.1 ng/ml) increased iNOS levels 40-fold in LECs. LSMCs cocultured with LECs pretreated with TNF had reduced expression of functional muscle genes. This reduction was prevented by ferulic acid, which blocked nitric oxide production. Local injection of L-N6-(1-iminoethyl)lysine 5-tetrazole-amide into inflamed paws of TNF-Tg mice resulted in recovery of lymphatic vessel contractions and drainage. Treatment of TNF-Tg mice with ferulic acid reduced synovial inflammation as well as cartilage and bone erosion, and it also restored lymphatic contraction and drainage.ConclusionsiNOS is produced primarily by LECs in lymphatic vessel efferent from inflamed joints of TNF-Tg mice in response to TNF and inhibits LSMC contraction and lymph drainage. Ferulic acid represents a potential new therapy to restore lymphatic function and thus improve inflammatory arthritis by inhibiting local production of nitric oxide by LSMCs.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-0963-8) contains supplementary material, which is available to authorized users.

Mouse aorta-derived mesenchymal progenitor cells contribute to and enhance the immune response of macrophage cells under inflammatory conditions.

IntroductionMesenchymal progenitor cells interact with immune cells and modulate inflammatory responses. The cellular characteristics required for this modulation are under fervent investigation. Upon interaction with macrophage cells, they can contribute to or suppress an inflammatory response. Current studies have focused on mesenchymal progenitors derived from bone marrow, adipose, and placenta. However, the arterial wall contains many mesenchymal progenitor cells, which during vascular disease progression have the potential to interact with macrophage cells. To examine the consequence of vascular-tissue progenitor cell-macrophage cell interactions in an inflammatory environment, we used a recently established mesenchymal progenitor cell line derived from the mouse aorta.MethodsMouse bone marrow-derived macrophage (MΦ) cells and mouse aorta-derived mesenchymal progenitor (mAo) cells were cultured alone or co-cultured directly and indirectly. Cells were treated with oxidized low-density lipoprotein (ox-LDL) or exposed to the inflammatory mediators lipopolysaccharide (LPS) and interferon-gamma (IFNγ) or both. A Toll-like receptor-4 (TLR4)-deficient macrophage cell line was used to determine the role of the mAo cells. To monitor inflammation, nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFα) secretions were measured.ResultsMesenchymal progenitor cells isolated from aorta and cloned by high proliferative capacity (mAo) can differentiate into multiple mesenchymal lineages and are positive for several commonly used mouse mesenchymal stem cell markers (that is, CD29, CD44, CD105, CD106, and Sca-1) but are negative for CD73 and ecto-5′-nucleotidase. In co-culture with MΦ cells, they increase MΦ oxidized-LDL uptake by 52.2%. In an inflammatory environment, they synergistically and additively contribute to local production of both NO and IL-6. After exposure to ox-LDL, the inflammatory response of MΦ cells to LPS and LPS/IFNγ is muted. However, when lipid-laden MΦ cells are co-cultured with mAo cell progenitors, the muted response is recovered and the contribution by the mAo cell progenitor is dependent upon cell contact.ConclusionsThe resident mesenchymal progenitor cell is a potential contributor to vascular inflammation when in contact with inflamed and lipid-laden MΦ cells. This interaction represents an additional target in vascular disease treatment. The potential for resident cells to contribute to the local immune response should be considered when designing therapeutics targeting inflammatory vascular disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-015-0071-8) contains supplementary material, which is available to authorized users.

Early adverse changes in liver microvascular circulation during experimental septic shock are not linked to an absolute nitric oxide deficit

Nitric oxide (NO) is believed to play a key role in adverse microvascular changes during sepsis. A deficit in NO has been evoked as a potential mechanism of microcirculatory deterioration in the early phase of septic shock. The aim of this study was to evaluate simultaneously and continuously both hepatic microcirculation and local NO production during early experimental sepsis.Wistar male rats were divided into two groups: a sepsis group undergoing cecal ligation and puncture (CLP) peritonitis and a control group undergoing sham surgery. Hepatic microcirculation was continuously monitored using a laser Doppler probe and local nitric oxide (NO) production by means of a specific electrode. Constitutive and inducible NO synthase production was assessed 2h after surgery, at onset of shock, and at 2 and 3h after shock.In control animals, hepatic microcirculatory perfusion and NO production remained stable throughout the experiment. In septic animals, whereas a fall in microcirculatory perfusion was noted as early as 2h after CLP, NO concentration remained stable and further increased after the onset of shock. At this time, inducible NO synthase was the only isoform significantly elevated.In this non-resuscitated experimental model of sepsis, an absolute liver deficit of NO could not explain the early adverse changes in the local microvascular system.

ON NO—The Continuing Story of Nitric Oxide, Diabetes, and Cardiovascular Disease

Nitric oxide (NO) is a simple chemical compound—1 nitrogen and 1 oxygen atom coupled together—with complex biological actions (1,2). A singularly prominent feature of NO is its ability to cause vasodilation, a quality that is used pharmacologically when treating ischemic heart disease with NO precursors such as nitroglycerin. In 1980, Furchgott and Zawadzki (3) showed that vascular relaxation induced by acetylcholine was dependent on the presence of endothelium and provided evidence for the release of a volatile humoral factor. This substance, later called endothelium-derived relaxing factor and now recognized as NO (4), is a significant component of the insulin-signaling cascade (Fig. 1), executing microvascular vasodilation stimulated by local NO production from the vascular endothelium (5). Vasodilation has the potential to decrease systemic blood pressure and increase local tissue blood flow in tissues such as muscle. The combination of decreased blood pressure and increased tissue blood flow, together with specific beneficial endothelial effects, may serve to prevent hypertension, cardiovascular disease, and insulin resistance (5,6). However, these effects remain exquisitely sensitive to impaired insulin signaling within the endogenous cardiovascular NO system and appear to be compromised in the presence of insulin resistance (7). So there is evidence that impaired NO-dependent vasodilation causes hypertension and insulin resistance and vice versa: that insulin resistance, such as that observed in diabetes, the metabolic syndrome, and hypertension, …

Local anesthetics inhibit nitric oxide production and l-arginine uptake in cultured bovine aortic endothelial cells

Previous studies have shown that local anesthetics have various effects on nitric oxide (NO) production, but the mechanisms remain unclear. The purpose of this study was to evaluate the effects of local anesthetics on NO production and 2-amino-5-guanidinopentanoic acid (l-arginine) uptake in one cell line. Cultured bovine aortic endothelial cells (BAEC) were stimulated with bradykinin and/or acetylcholine to activate endothelial NO synthase (NOS). BAEC were also incubated with interleukin-1β and lipopolysaccharide to stimulate inducible NOS. NO production was measured with the rapid spectrophotometric method, and l-arginine uptake was measured with high performance liquid chromatography. To assess the effects of local anesthetics, NO production and l-arginine uptake were measured in the presence or absence of procaine or lidocaine. NO was produced in BAEC stimulated with bradykinin and acetylcholine or interleukin-1β and lipopolysaccharide, but NO production was not affected by the addition of superoxide dismutase. In the cells stimulated with bradykinin and acetylcholine, 10μM each of procaine and lidocaine significantly inhibited NO production by 35% and 20%, respectively. In the cells incubated with interleukin-1ß and lipopolysaccharide, the same quantities of procaine and lidocaine significantly inhibited NO production by 15% and 10%, respectively. Both procaine and lidocaine significantly suppressed l-arginine uptake in BAEC stimulated with either bradykinin/acetylcholine or interleukin-1β/lipopolysaccharide. It is suggested that inhibitory effects of procaine and lidocaine on NO production are partially due to suppression of l-arginine uptake.

Study of nitric oxide metabolites (NOx) production during human hydatidosis: Relationship with cyst fertility

Event Abstract Back to Event Study of nitric oxide metabolites (NOx) production during human hydatidosis: Relationship with cyst fertility Razika Zeghir-Bouteldja1, 2* and Chafia Touil-Boukoffa2 1 University Akli Mohand Oulhadj, , Algeria 2 USTHB, Algeria Nitric oxide (NO) and its stable metabolites nitrite and nitrate (NO2−+ NO3−) have been identified as major effector molecules during the majority of parasitic infections. Production of NO has been shown to be induced by interferon gamma (IFN-γ) during human hydatidosis suggesting the relevant role of NO in the host defense. This parasitic infection constitutes a major health problem in Algeria. It is characterized by a prolonged coexistence of Echinococcus granulosus and its host without effective rejection of the parasite. In this study, we investigated in vivo production of NO products NOx (NO2−+ NO3−) in sera of Algerian patients carrying different cyst locations. NOx levels were evaluated by the Griess method. Our results indicated that the levels of NOx were significantly higher in the sera of hydatic patients than those of healthy controls supporting the possible involvement of NO in antihydatic action. The levels of NOx in sera of the patients with hepatic hydatidosis were significantly higher than those with pulmonary infection. The lower serum NOx levels were observed in the relapsing cases. In the current study, our results show high levels of NOx in fertile liver and lung fluids compared to infertile fluids. Our results suggest that the presence of NO products in hydatic fluids seems to be related to the location and the fertility of hydatic cysts. In addition, the presence of NO products in the cyst fluid suggests a possible local NO production by the larvae. Acknowledgements The authors wish to thank the technical and surgical staff of the Mustapha Bacha Hospital of Algiers for providing serum and cyst samples. A special thanks goes to Professor Hamrioui. They thank all the voluntary participants in this study. They are grateful to Dr. Wietzerbin for helpful discussions. This work was supported by a grant from the ANDRS (National Agency for Development of Scientific Research). Keywords: Echinococcus granulosus, Nitric oxide metabolites, Nitrite and nitrate, Cyst location, Hydatic fluid fertility Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Host-pathogen interactions Citation: Zeghir-Bouteldja R and Touil-Boukoffa C (2013). Study of nitric oxide metabolites (NOx) production during human hydatidosis: Relationship with cyst fertility. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00522 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Apr 2013; Published Online: 22 Aug 2013. * Correspondence: Dr. Razika Zeghir-Bouteldja, University Akli Mohand Oulhadj,, Bouira, Algeria, bouteldja_raz@yahoo.fr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Razika Zeghir-Bouteldja Chafia Touil-Boukoffa Google Razika Zeghir-Bouteldja Chafia Touil-Boukoffa Google Scholar Razika Zeghir-Bouteldja Chafia Touil-Boukoffa PubMed Razika Zeghir-Bouteldja Chafia Touil-Boukoffa Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Nitric Oxide–Producing Myeloid-Derived Suppressor Cells Inhibit Vascular E-Selectin Expression in Human Squamous Cell Carcinomas

Squamous cell carcinomas (SCC) are sun-induced skin cancers that are particularly numerous and aggressive in immunosuppressed individuals. SCC evade immune detection at least in part by down-regulating E-selectin on tumor vessels, thereby restricting entry of skin homing T cells into tumors. We find that nitric oxide potently suppresses E-selectin expression on human endothelial cells and that SCC are infiltrated by nitric oxide-producing iNOS+ CD11b+ CD33+ CD11c− HLA-DR− myeloid-derived suppressor cells (MDSC). MDSC from SCC produced NO, TGFβ and arginase and inhibited endothelial E-selectin expression in vitro. MDSC from SCC expressed the chemokine receptor CCR2 and tumors expressed the CCR2 ligand HBD3, suggesting CCR2-HBD3 interactions may contribute to MDSC recruitment to SCC. Treatment of SCC in vitro with the iNOS inhibitor L-NNA induced E-selectin expression at levels comparable to imiquimod-treated SCC undergoing immunologic destruction. Our results suggest that local production of NO in SCC may impair vascular E-selectin expression. We show that MDSC are critical producers of NO in SCC and that NO inhibition restores vascular E-selectin expression, potentially enhancing T cell recruitment. iNOS inhibitors and other therapies that reduce NO production may therefore be effective in the treatment of SCC and their premalignant precursor lesions actinic keratoses.

Stroke‐associated inflammation: is von Willebrand factor a ‘bad guy’?

Stroke‐associated inflammation: is von Willebrand factor a ‘bad guy’?

Brain edema in diseases of different etiology

Cerebral edema is a potentially life-threatening complication shared by diseases of different etiology, such as diabetic ketoacidosis, acute liver failure, high altitude exposure, dialysis disequilibrium syndrome, and salicylate intoxication. Pulmonary edema is also habitually present in these disorders, indicating that the microcirculatory disturbance causing edema is not confined to the brain. Both cerebral and pulmonary subclinical edema may be detected before it becomes clinically evident. Available evidence suggests that tissue hypoxia or intracellular acidosis is a commonality occurring in all of these disorders. Tissue ischemia induces physiological compensatory mechanisms to ensure cell oxygenation and carbon dioxide removal from tissues, including hyperventilation, elevation of red blood cell 2,3-bisphosphoglycerate content, and capillary vasodilatation. Clinical, laboratory, and necropsy findings in these diseases confirm the occurrence of low plasma carbon dioxide partial pressure, increased erythrocyte 2,3-bisphosphoglycerate concentration, and capillary vasodilatation with increased vascular permeability in all of them. Baseline tissue hypoxia or intracellular acidosis induced by the disease may further deteriorate when tissue oxygen requirement is no longer matched to oxygen delivery resulting in massive capillary vasodilatation with increased vascular permeability and plasma fluid leakage into the interstitial compartment leading to edema affecting the brain, lung, and other organs. Causative factors involved in the progression from physiological adaptation to devastating clinical edema are not well known and may include uncontrolled disease, malfunctioning adaptive responses, or unknown factors. The role of carbon monoxide and local nitric oxide production influencing tissue oxygenation is unclear