0
Original Research: EXHALED BREATH CONDENSATES |

Effect of an Inducible Nitric Oxide Synthase Inhibitor on Differential Flow-Exhaled Nitric Oxide in Asthmatic Patients and Healthy Volunteers* FREE TO VIEW

Caterina Brindicci, MD; Kazuhiro Ito, PhD; Peter J. Barnes, DM, DSc, FCCP; Sergei A. Kharitonov, MD, PhD
Author and Funding Information

*From the Section of Airway Diseases, National Heart and Lung Institute, Imperial College, London, UK.

Correspondence to: Sergei A. Kharitonov, MD, PhD, Section of Airway Disease, National Heart & Lung Institute, Imperial College, Dovehouse St, London SW3 6LY, UK; e-mail: s.kharitonov@imperial.ac.uk



Chest. 2007;132(2):581-588. doi:10.1378/chest.06-3046
Text Size: A A A
Published online

Nitric oxide (NO) is produced by a variety of cells within the respiratory tract, particularly airway epithelial cells, and its increased concentration in asthma is likely to derive from inducible NO synthase (iNOS) expressed in inflamed airways. To evaluate whether an increased bronchial flux of NO (ie, airway wall NO flux [Jno] in picoliters per second) produced in the large airways is due to an enzyme overexpression, we administered a relatively selective iNOS inhibitor, aminoguanidine, by nebulization in a double-blind, placebo-controlled manner in asthmatic and healthy subjects and also investigated whether the same concentration of inhibitor has any effect on NO produced in the peripheral lungs (ie, alveolar NO concentration [Calv] in parts per billion [ppb]) or on the diffusing capacity of NO (Dno) [in picoliters per second−1 per ppb−1) in the airways. Aminoguanidine administration resulted in a significant reduction in Jno compared with administration of the saline solution control in eight healthy subjects and in eight patients with asthma but caused no significant changes in Calv or in Dno in either group. No rise in BP, fall in FEV1, or adverse effects were observed in either group. These results indicate that iNOS from larger airways is the predominant source of elevated large airway-derived NO in patients with asthma, and that exhaled NO from peripheral lungs is not affected by a nebulized iNOS inhibitor and, therefore, is more likely to be derived form constitutive forms of NO synthase.

Figures in this Article

Nitric oxide (NO) is a gaseous mediator that is involved in many physiologic and pathologic processes. NO is synthesized by the NO synthase (NOS) family of enzymes that catalyze the oxidation of the amino acid L-arginine to L-citrulline with the release of NO. Three isoforms of NOS exist. Constitutive enzymes (ie, constitutive NOS [cNOS], which includes neuronal NOS [nNOS; or NOS1] and endothelial NOS [or NOS3]) have been found in the endothelium and neurones, and are activated by a rise in the levels of intracellular calcium in response to physiologic stimuli and an inducible calcium-independent enzyme (ie, inducible NOS [iNOS], which is also called NOS2), which may be expressed after induction by cytokines and endotoxin in a number of cell types. The level of iNOS is increased in the airway epithelium of asthmatic patients, and its expression is reduced by the administration of glucocorticosteroids.12

The small amount of NO generated by the constitutive isoforms appears to be required for physiologic functions, such as neurotransmission, maintenance of vascular tone, and GI motility, whereas the excess amounts of NO generated by iNOS can cause tissue damage and generate cascades of other inflammatory mediators such as prostaglandins.

Analogues of L-arginine that act as a false substrate for NOS can be used as inhibitors of endogenous NO synthesis. The nonselective inhibitor, NG-monomethyl-L-arginine, when administered by inhalation, caused a fall in exhaled NO in healthy and asthmatic subjects,1 and protected against the bronchoconstrictor effects of bradykinin. NG-nitro-L-arginine methyl ester, another nonselective NOS inhibitor, did not alter ventilation-perfusion ratio in asthma patients,3nor did it affect allergen-induced early and late asthmatic responses.4A selective iNOS inhibitor, SC-51, caused a rapid reduction in levels of NO in exhaled breath following oral administration to both healthy volunteers and asthmatic patients.5

The relatively selective iNOS inhibitor aminoguanidine, when administered by nebulization, resulted in a significant reduction in exhaled NO levels in asthmatic patients but not in healthy subjects.6 This finding suggests that treatment with selective iNOS inhibitors might be beneficial in the treatment of asthma by reducing the amount of potentially damaging NO that is produced in the lungs.

A method measuring exhaled NO at multiple expiratory flows (MEFEno) has been used by several research groups712 to estimate exhaled NO sources in the lung. It is based on a simple two-compartment model of the lungs, which can be described by three flow-independent NO parameters, two of which characterize the airway compartment (airway diffusing capacity of NO [Dno] and either the maximum airway wall NO flux [Jno] or the airway wall NO concentration [Cw]) and one of which characterizes the alveolar region (alveolar NO concentration [Calv]). This model is able, to a certain degree, to partition exhaled NO into an airway source, which is reduced by the administration inhaled corticosteroids, and a peripheral source, which is not affected by this treatment.,8 The purpose of this study was to test whether the exhaled NO levels derived from the central and peripheral respiratory tracts are affected by aminoguanidine inhalation by comparing asthmatic patients and healthy control subjects.

Subjects

Sixteen subjects, comprising 8 nonsmokers and 8 nonsmoker asthmatic patients, took part to the study. The subjects were consecutively enrolled.

Asthmatic patients had mild intermittent asthma, as determined according to Global Initiative for Asthma guidelines criteria,13 and required only short-acting inhaled bronchodilators on an “as-required” basis. These patients had an FEV1 of ≥ 70% predicted, a documented reversibility of > 12% following administration of 200 μg of salbutamol, and airway hyperresponsiveness to methacholine with a provocative concentration of methacholine producing a 20% fall in FEV1 (in micromoles) of ≤ 8 mg/mL. All asthmatic patients were atopic as defined by a positive skin-prick test finding and radioallergosorbent test response to one or more of a full range of common allergens. Nonatopy was defined as a uniformly negative skin-prick test result (in the presence of appropriate controls) and a negative radioallergosorbent test response to the same allergens. None of the subjects studied had received oral or inhaled corticosteroids for the preceding 12 months, and none had experienced an exacerbation of asthma or a respiratory tract infection in the preceding 6 weeks.

Healthy control subjects were matched for age and sex, and had no clinically significant disease. All subjects were advised not to consume any nitrite-enriched food (ie, spinach) or caffeinated drinks for the 6 h before the study visits. The study was approved by the Ethics Committee of the Royal Brompton Hospital and Harefield National Health Service Trust, and all of the patients gave written informed consent.

Study Design

Before entering the study, all subjects were seen for a screening visit. The study consisted of two visits separated by an interval of 7 to 10 days. On each study day after baseline spirometry, NO measurements, and pulse and BP measurements were performed, subjects inhaled either aminoguanidine (Sigma; Poole, UK), dissolved in 2 mL of a 0.9% saline solution, or a saline solution control administered via a nebulizer (Sidestream; Medic-Aid; West Sussex, UK) using a mouthpiece and a nose clip over a 10-min period. Subjects inhaled 2 mL of the aminoguanidine solution, giving a total dose of 500 mg. The study was conducted in a double-blind fashion, and the order of inhalation was randomized. Spirometry, MEFEno, BP, and heart rate were measured at baseline and 1 h after inhalation of the solutions.

Lung Function

Spirometric and reversibility tests were performed using a dry spirometer (Vitalograph Ltd; Buckingham, UK). The best value from among three maneuvers was expressed as an absolute value (in liters) and as a percentage of the predicted value.

Skin Prick Testing

Standard skin sensitivity was measured for four common aeroallergens (ie, house dust mite, grass pollen, cat hair, and Aspergillus fumigatus) with negative and positive controls (Soluprick; ALK-Abello A/S; Horsholm, Denmark).

MEFEno Measurements

Exhaled NO was measured by a chemiluminescence analyzer (NIOX; Aerocrine AB; Stockholm, Sweden), which was calibrated according to the instructions of the manufacturer every 14 days. After inhaling NO-free air to total lung capacity, subjects exhaled at a constant flow rate against a resistor to measure the plateau NO concentration. Readings were taken at flow rates of 10, 100, 200, and 260 mL/s by applying resistors of 10, 50, 100, 200, and 300 cm H2O2 mL/s, respectively, to create and maintain the target flow rates. The exhalation times required were 20, 10, 10, 6, and 6 s, respectively, to ensure that the total volume of air exhaled at each flow rate accounted for the exclusion of the dead space.14 The mean amount of exhaled NO at each expiratory flow was calculated by the analyzer during an NO plateau of not less than 3 s with NO variability within 10% of the plateau or ± 1 part per billion (ppb). Jno, Dno, and Calv were calculated according to the following equation:

where the exhaled concentration (Cexh [in ppb]) is a function of the residence time (Tres) of each differential bolus of air in the airway compartment, the volume of the airway compartment (Vair) and the remaining three parameters (Jno, Dno, and Calv).

Calv and Jno can be estimated by using the slope and the intercept of a resulting linear relationship by measuring the elimination rate of NO from the breath during exhalation (Vno) at multiple constant exhalation flow rates (VEs):

Once Calv and Jno were calculated, Dno was estimated according to the equation (using the solver tool in Excel; Microsoft; Richmond, CA). We then calculated the Cw, which is simply the Jno/Dno ratio.

Statistical Analysis

Nonparametric tests were applied as the distribution of these variables was not known and there were insufficient data for normal distribution analysis (Prism 4 software; Graph Pad Software Inc; San Diego, CA). The data were expressed as the medians and interquartile range (IQR) and the median and 95% confidence intervals.

The Student paired t test was used to compare the fraction of exhaled NO (FEno) values and NO model parameters in two study visits, and the reproducibility was assessed by Bland-Altman test and intraclass correlation coefficient for all the subjects.

A value of p < 0.05 was considered to be significant. Sample size and/or power was calculated; the level of α was set at 0.05 (5%), and the power was set at 80% with β at 0.2.

The characteristics of subjects at baseline are shown in Table 1 . Aminoguanidine inhalation caused a highly significant reduction in median Jno in both asthmatic patients (1,814 pL/s [IQR, 1,240 to 3,922 pL/s] vs 288 pL/s [IQR, 232 to 755 pL/s]; p < 0.0001) and healthy control subjects (776 pL/s [IQR, 663 to 878 pL/s] vs 276 pL/s [IQR, 192 to 416 pL/s]; p < 0.0001) [Fig 1 , Table 2 ], and in median Cw in both asthmatic patients (136.6 [IQR, 72.6 to 196.8] vs 20.9 [IQR, 17.3 to 55.1]; p < 0.0001) and healthy control subjects (68.2 [IQR, 56.5 to 70.2] vs 19.8 [IQR, 15.3 to 26]; p < 0.0001) [Table 2].

However, aminoguanidine inhalation did not cause any significant fall in median Calv levels in asthmatic patients (2.1 ppb [IQR, 1.8 to 2.3 ppb] vs 2 ppb [IQR, 1.7 to 2.1 ppb] nor in healthy control subjects (1.7 ppb [IQR, 1.6 to 2.1 ppb] vs 1.6 ppb [IQR, 1.5 to 1.9 ppb]) [Fig 2 , Table 2] and did not cause any decrease in median Dno in asthmatic subjects (15.9 pL/s−1/ppb−1 [IQR, 14.7 to 20 pL/s−1/ppb−1] vs 14.5 pL/s−1/ppb−1 [IQR, 12.3 to 16.8 pL/s−1/ppb−1]) nor in healthy subjects (12.5 pL/s−1/ppb−1 [IQR, 9.4 to 12.9 pL/s−1/ppb−1] vs 13.9 pL/s−1/ppb−1 [IQR, 10.7 to 17.6 pL/s−1/ppb−1]) [Fig 3 , Table 2]. After placebo administration, no effects were seen on Jno, Calv, Dno, and Cw in either subject group (Table 2, Figs 123).

FEV1 showed no significant change after inhalation in either healthy or asthmatic subjects, and BP and heart rate did not show any significant alterations (Table 2). No adverse effects were observed or reported. The FEno readings at all five flow rates and NO model parameters were highly reproducible, and there was no significant day-to-day variation (p > 0.05 for all comparisons) [Table 3 , Fig 4, 5 ].

The iNOS inhibitor, aminoguanidine, was well tolerated in all subjects and caused a rapid reduction in Jno following inhaled administration to both healthy volunteers and asthmatic patients. Even though Jno levels were reduced dramatically following treatment with aminoguanidine, no change was seen in lung function, either in asthma patients or in healthy volunteers.

Our data indicate that Jno can be effectively decreased by a single dose of inhaled NOS inhibitors in both asthma patients and healthy control subjects with a greater reduction in patients with asthma (80.3% vs 61.3%, respectively). This supports the hypothesis that iNOS induction may be responsible for the raised Jno levels in asthma patients, whereas the levels seen in healthy subjects seem to be due to cNOS and a low level of iNOS activity. These data are consistent with the measurements made with a more selective iNOS inhibitor, SC-51, which showed a marked reduction in exhaled NO in asthmatic patients but also some reduction in healthy subjects when exhaled NO was measured by conventional techniques.5

The cellular source of the raised endogenous NO is uncertain. Immunostaining for cNOS has been reported in alveolar and airway epithelial cells of healthy individuals,15and there is evidence for a low level of expression of iNOS in airway epithelial cells of healthy subjects with a greater increase occurring in the asthmatic patients compared.16NO may be induced in a variety of superficial cells in the respiratory tract, including macrophages, epithelial cells, and infiltrating inflammatory cells. Human airway epithelial cells express iNOS after exposure to proinflammatory cytokines in vitro,17 and this could contribute to the increase in exhaled NO in asthmatic subjects. There is an expanding body of research supporting an important role for NO in human asthma.1820 Selective iNOS inhibitors have been shown to suppress eosinophil infiltration to the lung in models of allergic airway inflammation2122 with decreased lung chemokine expression23and inhibited allergic airway inflammation in mice deficient in iNOS.24The selective inhibition of iNOS has considerable therapeutic potential in a population of patients with severe asthma receiving treatment with oral steroids and with elevated NO levels,25 since iNOS inhibitors may be effective in situations where steroids are poorly effective, such as in some patients with severe asthma.

The lack of effect of nebulized aminoguanidine on Calv can potentially be explained by an insufficient delivery of the drug into the peripheral airways. Accordingly, the reduction in Jno can be explained by its preferential deposition in large airways, whereas in peripheral airways it did not exert any significant effect because it cannot reach a significant dose of deposition. Another possibility is that the dosage used, which was equal to that used in a previous study,6 was insufficient. This dosage was established empirically given the lack of dose-response data. Accordingly, a greater dosage of aminoguanidine may have exerted a different effect. Another possibility is that NO generation is accomplished predominantly by cNOS isoforms in the lung periphery, and that these are less effectively inhibited by aminoguanidine.

Whereas aminoguanidine has a partial selectivity for iNOS vs endothelial NOS (approximately 10-fold), the selectivity over nNOS is minimal.2 This has been widely used to probe the effects of iNOS inhibition, but caution is necessary in attributing the effects observed purely to iNOS inhibition. With only fivefold in vitro selectivity, it is possible that nNOS is being inhibited in addition to iNOS, especially at the 500-mg dose despite the pharmacokinetic data.

We agreed that with a potentially low total dose that is nebulized, aminoguanidine would still selectively inhibit iNOS in the proximal airways, but concentration in the lung periphery would be too low, perhaps, to make any conclusions on the role of iNOS in the periphery. On the other hand, the effects on bronchial NO were demonstrated to be of rapid onset.

It has been proven already in previous studies1,4,6,26 that with high doses of nonselective inhibitors such as NG-nitro-L-arginine methyl ester, NG-monomethyl-L-arginine, or aminoguanidine, a 200-mg dose caused a 70% inhibition of exhaled NO levels measured on a standard flow. Assuming that the complete inhibition of iNOS has been selectively obtained, the residual bronchial NO in healthy control subjects and asthmatic patients may be produced by cNOS as well as exogenous atmospheric sources. In addition, the duration of effects in terms of lowering bronchial NO following a single dose, suggests that the dosing regimen for this compound could be adjusted to permit single daily dosing.

Aminoguanidine, when administered at the dose used, may be able to inhibit cNOS and iNOS within the epithelial layer, and it is possible that this layer may act as a metabolic or diffusional barrier for aminoguanidine, preventing the particular dose from acting on sources of NOS that are situated more deeply within the airway parenchyma. If the lack of effect of aminoguanidine on alveolar NO reflects poor penetration through the epithelial layer, the synthesis of physiologically important endogenous NO within deeper structures may not be inhibited. This may lead to the misinterpretation of negative results on alveolar NO.

Aminoguanidine had no significant effect on Dno in asthmatic patients and healthy control subjects, implying that airway iNOS activity was located within the area of NO production by cNOS. Patients with asthma who were included in this study had mild disease; most patients were asymptomatic with only mildly impaired lung function. Although no convincing effects were noted on lung function or on symptoms of asthma, this population is not suitable to prove potential clinical efficacy; the measurements of NO parameters in asthmatic patients should be a useful method to assess the pharmacodynamic properties of iNOS inhibitors in inflammatory conditions. The lack of effect of aminoguanidine on spirometry findings suggests that endogenous NO does not have a critical role in the regulation of airway tone, even in patients with asthma who have elevated production. We only administered a single dose, and it is uncertain whether long-term administration might have different effects. The reduction in Jno production was not associated with any measurable change in BP or heart rate, suggesting that the reduction was insufficient to affect the systemic circulation.

Sample size determination is often an important step in planning such studies. According to these data, a small number of asthmatic subjects (between 7 and 10) was required to demonstrate an effect of 80 to 90% by aminoguanidine in this study.

In conclusion, this study has attempted to evaluate further the role of aminoguanidine in the regulation of NOS and its effects on NO produced from central airways vs peripheral airways. Further studies need to be undertaken to determine the exact mechanisms by which aminoguanidine acts on NOS isoforms as well as to define its site of action. The effects of nebulized NOS inhibitors at higher doses or its daily use should also be considered, and other inflammatory diseases characterized by an increased NO in periphery airways (eg, in COPD patients) need to be investigated.

Abbreviations: Calv = alveolar nitric oxide concentration; cNOS = constitutive nitric oxide synthase; Cw = airway wall nitric oxide concentration; Dno = airway diffusing capacity of nitric oxide; FEno = fraction of exhaled nitric oxide; iNOS = inducible nitric oxide synthase; IQR = interquartile range; Jno = airway wall nitric oxide flux; MEFEno = exhaled nitric oxide at multiple expiratory flows; nNOS = neuronal nitric oxide synthase; NO = nitric oxide; NOS = nitric oxide synthase; ppb = parts per billion

The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organization whose products or services may be discussed in this article.

Table Graphic Jump Location
Table 1. Subject Characteristics at Baseline*
* 

Values are given as the mean (95% CI) or geometric mean ± SEM, unless otherwise indicated. H = house dust mite; G = grass pollen; C = cat; SABA = short-acting β2-agonist; PC20 = provocative concentration of methacholine producing a 20% fall in FEV1.

Figure Jump LinkFigure 1. Effects of aminoguanidine or placebo on bronchial Jno in asthma patients (top left, A, and top right, B, respectively) and in healthy control subjects (bottom left, C, and bottom right, D, respectively).Grahic Jump Location
Table Graphic Jump Location
Table 2. Effects of Aminoguanidine/Placebo Inhalation in the Studied Groups*
* 

Values are given as the median (95% confidence interval) or the mean ± SEM, unless otherwise indicated. FEF25–75 = forced expiratory flow during 25 to 75% of the FVC.

 

p < 0.0001.

Figure Jump LinkFigure 2. Effects of aminoguanidine or placebo on Calv NO in asthma patients (top left, A, and top right, B, respectively) and in healthy control subjects (bottom left, C, and bottom right, D, respectively).Grahic Jump Location
Figure Jump LinkFigure 3. Effects of aminoguanidine or placebo on Dno in asthma patients (top left, A, and top right, B, respectively) and in healthy control subjects (bottom left, C, and bottom right, D, respectively).Grahic Jump Location
Table Graphic Jump Location
Table 3. Exhaled NO at Multiple Expiratory Flows Measurements and NO Parameters in the Studied Groups*
* 

Values are given as the median (95% confidence interval). ICC = intraclass correlation coefficient.

Figure Jump LinkFigure 4. Bland-Altman analysis for the repeatability of the values for FEno measured at flow rates of 10 mL/s (top left, a), 50 mL/s (top right, b), 100 mL/s (middle left, c), 200 mL/s (middle right, d), and 300 mL/s (bottom, e) at baseline in two visits.Grahic Jump Location
Figure Jump LinkFigure 5. Bland-Altman analysis for the repeatability of Jno (top left, a), Calv (top right, b), and Dno (bottom, c) values measured at baseline in two visits.Grahic Jump Location
Yates, DH, Kharitonov, SA, Robbins, RA, et al (1995) Effect of a nitric oxide synthase inhibitor and a glucocorticosteroid on exhaled nitric oxide.Am J Respir Crit Care Med152,892-896. [PubMed]
 
Alderton, WK, Cooper, CE, Knowles, RG Nitric oxide synthases: structure, function and inhibition.Biochem J2001;357,593-615. [PubMed] [CrossRef]
 
Gomez, FP, Barbera, JA, Roca, J, et al Effect of nitric oxide synthesis inhibition with nebulized L-NAME on ventilation-perfusion distributions in bronchial asthma.Eur Respir J1998;12,865-871. [PubMed]
 
Taylor, DA, McGrath, JL, O’Connor, BJ, et al Allergen-induced early and late asthmatic responses are not affected by inhibition of endogenous nitric oxide.Am J Respir Crit Care Med1998;158,99-106. [PubMed]
 
Hansel, TT, Kharitonov, SA, Donnelly, LE, et al A selective inhibitor of inducible nitric oxide synthase inhibits exhaled breath nitric oxide in healthy volunteers and asthmatics.FASEB J2003;17,1298-1300. [PubMed]
 
Yates, DH, Kharitonov, SA, Thomas, PS, et al Endogenous nitric oxide is decreased in asthmatic patients by an inhibitor of inducible nitric oxide synthase.Am J Respir Crit Care Med1996;154,247-250. [PubMed]
 
Brindicci, C, Ito, K, Resta, O, et al Exhaled nitric oxide from lung periphery is increased in COPD.Eur Respir J2005;26,52-59. [PubMed]
 
Lehtimaki, L, Kankaanranta, H, Saarelainen, S, et al Extended exhaled NO measurement differentiates between alveolar and bronchial inflammation.Am J Respir Crit Care Med2001;163,1557-1561. [PubMed]
 
Hogman, M, Holmkvist, T, Wegener, T, et al Extended NO analysis applied to patients with COPD, allergic asthma and allergic rhinitis.Respir Med2002;96,24-30. [PubMed]
 
Silkoff, PE, Sylvester, JT, Zamel, N, et al Airway nitric oxide diffusion in asthma: role in pulmonary function and bronchial responsiveness.Am J Respir Crit Care Med2000;161,1218-1228. [PubMed]
 
van Veen, IH, Sterk, PJ, Schot, R, et al Alveolar nitric oxide versus measures of peripheral airway dysfunction in severe asthma.Eur Respir J2006;27,951-956. [PubMed]
 
George, SC, Hogman, M, Permutt, S, et al Modeling pulmonary nitric oxide exchange.J Appl Physiol2004;96,831-839. [PubMed]
 
Global Initiative for Asthma... Global strategy for asthma management and prevention: NHLBI/WHO workshop report. 2005; National Institutes of Health, National Heart, Lung and Blood Institute. Bethesda, MD: NIH Publication No. 02-3659.
 
American Thoracic Society, European Respiratory Society.. ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med2005;171,912-930. [PubMed]
 
Kobzik, L, Bredt, DS, Lowenstein, CJ, et al Nitric oxide synthase in human and rat lung: immunocytochemical and histochemical localization.Am J Respir Cell Mol Biol1993;9,371-377. [PubMed]
 
Hamid, Q, Springall, DR, Riveros-Moreno, V, et al Induction of nitric oxide synthase in asthma.Lancet1993;342,1510-1513. [PubMed]
 
Robbins, RA, Barnes, PJ, Springall, DR, et al Expression of inducible nitric oxide in human lung epithelial cells.Biochem Biophys Res Commun1994;203,209-218. [PubMed]
 
Singh, S, Evans, TW Nitric oxide, the biological mediator of the decade: fact or fiction?Eur Respir J1997;10,699-707. [PubMed]
 
Kharitonov, SA, Barnes, PJ Exhaled markers of pulmonary disease.Am J Respir Crit Care Med2001;163,1693-1722. [PubMed]
 
Hart, CM Nitric oxide in adult lung disease.Chest1999;115,1407-1417. [PubMed]
 
Koarai, A, Ichinose, M, Sugiura, H, et al Allergic airway hyperresponsiveness and eosinophil infiltration is reduced by a selective iNOS inhibitor, 1400W, in mice.Pulm Pharmacol Ther2000;13,267-275. [PubMed]
 
Tulic, MK, Wale, JL, Holt, PG, et al Differential effects of nitric oxide synthase inhibitors in an in vivo allergic rat model.Eur Respir J2000;15,870-877. [PubMed]
 
Trifilieff, A, Fujitani, Y, Mentz, F, et al Inducible nitric oxide synthase inhibitors suppress airway inflammation in mice through down-regulation of chemokine expression.J Immunol2000;165,1526-1533. [PubMed]
 
Xiong, Y, Karupiah, G, Hogan, SP, et al Inhibition of allergic airway inflammation in mice lacking nitric oxide synthase 2.J Immunol1999;162,445-452. [PubMed]
 
Stirling, RG, Kharitonov, SA, Campbell, D, et al Increase in exhaled nitric oxide levels in patients with difficult asthma and correlation with symptoms and disease severity despite treatment with oral and inhaled corticosteroids: Asthma and Allergy Group.Thorax1998;53,1030-1034. [PubMed]
 
Taylor, DA, McGrath, JL, Orr, LM, et al Effect of endogenous nitric oxide inhibition on airway responsiveness to histamine and adenosine-5′-monophosphate in asthma.Thorax1998;53,483-489. [PubMed]
 

Figures

Figure Jump LinkFigure 1. Effects of aminoguanidine or placebo on bronchial Jno in asthma patients (top left, A, and top right, B, respectively) and in healthy control subjects (bottom left, C, and bottom right, D, respectively).Grahic Jump Location
Figure Jump LinkFigure 2. Effects of aminoguanidine or placebo on Calv NO in asthma patients (top left, A, and top right, B, respectively) and in healthy control subjects (bottom left, C, and bottom right, D, respectively).Grahic Jump Location
Figure Jump LinkFigure 3. Effects of aminoguanidine or placebo on Dno in asthma patients (top left, A, and top right, B, respectively) and in healthy control subjects (bottom left, C, and bottom right, D, respectively).Grahic Jump Location
Figure Jump LinkFigure 4. Bland-Altman analysis for the repeatability of the values for FEno measured at flow rates of 10 mL/s (top left, a), 50 mL/s (top right, b), 100 mL/s (middle left, c), 200 mL/s (middle right, d), and 300 mL/s (bottom, e) at baseline in two visits.Grahic Jump Location
Figure Jump LinkFigure 5. Bland-Altman analysis for the repeatability of Jno (top left, a), Calv (top right, b), and Dno (bottom, c) values measured at baseline in two visits.Grahic Jump Location

Tables

Table Graphic Jump Location
Table 1. Subject Characteristics at Baseline*
* 

Values are given as the mean (95% CI) or geometric mean ± SEM, unless otherwise indicated. H = house dust mite; G = grass pollen; C = cat; SABA = short-acting β2-agonist; PC20 = provocative concentration of methacholine producing a 20% fall in FEV1.

Table Graphic Jump Location
Table 2. Effects of Aminoguanidine/Placebo Inhalation in the Studied Groups*
* 

Values are given as the median (95% confidence interval) or the mean ± SEM, unless otherwise indicated. FEF25–75 = forced expiratory flow during 25 to 75% of the FVC.

 

p < 0.0001.

Table Graphic Jump Location
Table 3. Exhaled NO at Multiple Expiratory Flows Measurements and NO Parameters in the Studied Groups*
* 

Values are given as the median (95% confidence interval). ICC = intraclass correlation coefficient.

References

Yates, DH, Kharitonov, SA, Robbins, RA, et al (1995) Effect of a nitric oxide synthase inhibitor and a glucocorticosteroid on exhaled nitric oxide.Am J Respir Crit Care Med152,892-896. [PubMed]
 
Alderton, WK, Cooper, CE, Knowles, RG Nitric oxide synthases: structure, function and inhibition.Biochem J2001;357,593-615. [PubMed] [CrossRef]
 
Gomez, FP, Barbera, JA, Roca, J, et al Effect of nitric oxide synthesis inhibition with nebulized L-NAME on ventilation-perfusion distributions in bronchial asthma.Eur Respir J1998;12,865-871. [PubMed]
 
Taylor, DA, McGrath, JL, O’Connor, BJ, et al Allergen-induced early and late asthmatic responses are not affected by inhibition of endogenous nitric oxide.Am J Respir Crit Care Med1998;158,99-106. [PubMed]
 
Hansel, TT, Kharitonov, SA, Donnelly, LE, et al A selective inhibitor of inducible nitric oxide synthase inhibits exhaled breath nitric oxide in healthy volunteers and asthmatics.FASEB J2003;17,1298-1300. [PubMed]
 
Yates, DH, Kharitonov, SA, Thomas, PS, et al Endogenous nitric oxide is decreased in asthmatic patients by an inhibitor of inducible nitric oxide synthase.Am J Respir Crit Care Med1996;154,247-250. [PubMed]
 
Brindicci, C, Ito, K, Resta, O, et al Exhaled nitric oxide from lung periphery is increased in COPD.Eur Respir J2005;26,52-59. [PubMed]
 
Lehtimaki, L, Kankaanranta, H, Saarelainen, S, et al Extended exhaled NO measurement differentiates between alveolar and bronchial inflammation.Am J Respir Crit Care Med2001;163,1557-1561. [PubMed]
 
Hogman, M, Holmkvist, T, Wegener, T, et al Extended NO analysis applied to patients with COPD, allergic asthma and allergic rhinitis.Respir Med2002;96,24-30. [PubMed]
 
Silkoff, PE, Sylvester, JT, Zamel, N, et al Airway nitric oxide diffusion in asthma: role in pulmonary function and bronchial responsiveness.Am J Respir Crit Care Med2000;161,1218-1228. [PubMed]
 
van Veen, IH, Sterk, PJ, Schot, R, et al Alveolar nitric oxide versus measures of peripheral airway dysfunction in severe asthma.Eur Respir J2006;27,951-956. [PubMed]
 
George, SC, Hogman, M, Permutt, S, et al Modeling pulmonary nitric oxide exchange.J Appl Physiol2004;96,831-839. [PubMed]
 
Global Initiative for Asthma... Global strategy for asthma management and prevention: NHLBI/WHO workshop report. 2005; National Institutes of Health, National Heart, Lung and Blood Institute. Bethesda, MD: NIH Publication No. 02-3659.
 
American Thoracic Society, European Respiratory Society.. ATS/ERS recommendations for standardized procedures for the online and offline measurement of exhaled lower respiratory nitric oxide and nasal nitric oxide, 2005.Am J Respir Crit Care Med2005;171,912-930. [PubMed]
 
Kobzik, L, Bredt, DS, Lowenstein, CJ, et al Nitric oxide synthase in human and rat lung: immunocytochemical and histochemical localization.Am J Respir Cell Mol Biol1993;9,371-377. [PubMed]
 
Hamid, Q, Springall, DR, Riveros-Moreno, V, et al Induction of nitric oxide synthase in asthma.Lancet1993;342,1510-1513. [PubMed]
 
Robbins, RA, Barnes, PJ, Springall, DR, et al Expression of inducible nitric oxide in human lung epithelial cells.Biochem Biophys Res Commun1994;203,209-218. [PubMed]
 
Singh, S, Evans, TW Nitric oxide, the biological mediator of the decade: fact or fiction?Eur Respir J1997;10,699-707. [PubMed]
 
Kharitonov, SA, Barnes, PJ Exhaled markers of pulmonary disease.Am J Respir Crit Care Med2001;163,1693-1722. [PubMed]
 
Hart, CM Nitric oxide in adult lung disease.Chest1999;115,1407-1417. [PubMed]
 
Koarai, A, Ichinose, M, Sugiura, H, et al Allergic airway hyperresponsiveness and eosinophil infiltration is reduced by a selective iNOS inhibitor, 1400W, in mice.Pulm Pharmacol Ther2000;13,267-275. [PubMed]
 
Tulic, MK, Wale, JL, Holt, PG, et al Differential effects of nitric oxide synthase inhibitors in an in vivo allergic rat model.Eur Respir J2000;15,870-877. [PubMed]
 
Trifilieff, A, Fujitani, Y, Mentz, F, et al Inducible nitric oxide synthase inhibitors suppress airway inflammation in mice through down-regulation of chemokine expression.J Immunol2000;165,1526-1533. [PubMed]
 
Xiong, Y, Karupiah, G, Hogan, SP, et al Inhibition of allergic airway inflammation in mice lacking nitric oxide synthase 2.J Immunol1999;162,445-452. [PubMed]
 
Stirling, RG, Kharitonov, SA, Campbell, D, et al Increase in exhaled nitric oxide levels in patients with difficult asthma and correlation with symptoms and disease severity despite treatment with oral and inhaled corticosteroids: Asthma and Allergy Group.Thorax1998;53,1030-1034. [PubMed]
 
Taylor, DA, McGrath, JL, Orr, LM, et al Effect of endogenous nitric oxide inhibition on airway responsiveness to histamine and adenosine-5′-monophosphate in asthma.Thorax1998;53,483-489. [PubMed]
 
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

CHEST Journal Articles
PubMed Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543