Decreased nitric oxide in the exhaled air of patients with systemic sclerosis with pulmonary hypertension

Nitric oxide and nursing: a review

AIMS AND OBJECTIVES

This paper, therefore, aimed to review published literature in this area of pharmacological exploitation, to look at the therapeutic applications and clinical relevance and, by so doing, provide an accessible source for nurses to gain insight into the role of nitric oxide in the clinical setting.

BACKGROUND

Nitric oxide is a chemical mediator fundamental in the maintenance of adequate tissue perfusion and effective cardiovascular function; a major endogenous regulator of vascular tone. The use of nitrates are well established as pharmacological agents but it is only recently that it has been recognized that they act as a source of nitric oxide. Although widely addressed within the medical literature, there appears to be a paucity of nursing literature that explores either its physiological action, or its relevance to nursing practice.

CONCLUSIONS

This literature review provides an overview of the use of nitric oxide and its implications for nursing practice and patient outcomes.

RELEVANCE TO CLINICAL PRACTICE

Knowledge of nitric oxide and its action is pertinent to nurses across diverse specialities. It helps in understanding the principles of many nitrogen-derived medications which nurses administer to their patients on a daily basis. In terms of oral medication, this is demonstrated by greater insights into the action of nitrates, the appreciation of surprising developments in medications such as sildenafil and the development of new drug opportunities such as nitric oxide-non-steroidal anti-inflammatory drugs. Equally, the use of inhaled nitric oxide therapy in adult and neonatal critical care units appears to be an increasingly valuable source of treatment. A particular research challenge is found in the attempt at nitric oxide inhibition in the management of septic shock. The authors argue that understanding such esoteric areas of therapeutic developments is increasingly to be part of the repertoire of knowledge and skills for nurses in the 21st century.

NOS2 polymorphisms associated with the susceptibility to pulmonary arterial hypertension with systemic sclerosis: contribution to the transcriptional activity

Systemic sclerosis (SSc) is a connective tissue disease characterized by tissue fibrosis. One of several complications of SSc, pulmonary arterial hypertension (PAH) can be refractory to treatment, both novel and established. In the present study we investigated the ratio of circulating nitric oxide to endothelin-1 in patients with both SSc and PAH, and determined whether polymorphisms in NOS2 (the nitric oxide synthase 2 gene) are associated with susceptibility to PAH. Endothelin-1 in plasma and nitric oxide metabolites (nitrate and nitrite) in serum were measured. The nitric oxide/endothelin-1 ratio was significantly lower in patients with both SSc and PAH than in patients with SSc only or in healthy control individuals. We confirmed the presence of two single nucleotide polymorphisms at positions -1,026 and -277 and a pentanucleotide repeat (CCTTT) at -2.5 kilobases. There were significant differences in single nucleotide polymorphisms between patients with SSc who had PAH and those who did not, and between patients with both SSc and PAH and healthy control individuals. The CCTTT repeat was significantly shorter in patients with both SSc and PAH than in patients with SSc only or in healthy control individuals. Transcriptional activity were analyzed using the luciferase reporter assay. The transcriptional activity of NOS2 was much greater in fibroblasts transfected by a vector with a long allele of the CCTTT repeat than in those transfected by a vector with a short allele. Polymorphisms in the NOS2 gene are associated with transcriptional activity of the NOS2 gene and with susceptibility to SSc-related PAH.

Exhaled nitric oxide measurements: clinical application and interpretation

The use of exhaled nitric oxide measurements (F(E)NO) in clinical practice is now coming of age. There are a number of theoretical and practical factors which have brought this about. Firstly, F(E)NO is a good surrogate marker for eosinophilic airway inflammation. High F(E)NO levels may be used to distinguish eosinophilic from non-eosinophilic pathologies. This information complements conventional pulmonary function testing in the assessment of patients with non-specific respiratory symptoms. Secondly, eosinophilic airway inflammation is steroid responsive. There are now sufficient data to justify the claim that F(E)NO measurements may be used successfully to identify and monitor steroid response as well as steroid requirements in the diagnosis and management of airways disease. F(E)NO measurements are also helpful in identifying patients who do/do not require ongoing treatment with inhaled steroids. Thirdly, portable nitric oxide analysers are now available, making routine testing a practical possibility. However, a number of issues still need to be resolved, including the diagnostic role of F(E)NO in preschool children and the use of reference values versus individual F(E)NO profiles in managing patients with difficult or severe asthma.

Abnormal exhaled ethane concentrations in scleroderma

Scleroderma (systemic sclerosis) is a chronic multisystem autoimmune disease in which oxidative stress is suspected to play a role in the pathophysiology. Therefore, it was postulated that patients with scleroderma would have abnormally high breath ethane concentrations, which is a volatile product of free-radical-mediated lipid peroxidation, compared with a group of controls. There was a significant difference (p<0.05) between the mean exhaled ethane concentration of 5.27 pmol ml(-1) CO(2) (SEM=0.76) in the scleroderma patients (n=36) versus the mean exhaled concentration of 2.72 pmol ml(-1) CO(2) (SEM=0.71) in a group of healthy controls (n=21). Within the scleroderma group, those subjects taking a calcium channel blocker had lower ethane concentrations compared with patients who were not taking these drugs (p=0.05). There was a significant inverse association between lung diffusion capacity for carbon monoxide (per cent of predicted) and ethane concentration (b=-2.8, p=0.026, CI=-5.2 to -0.35). These data support the presence of increased oxidative stress among patients with scleroderma that is detected by measuring breath ethane concentrations.

Pulmonary Involvement in Systemic Sclerosis

Scleroderma, also known as progressive systemic sclerosis (SSc), is a multisystem autoimmune disorder characterized by inflammation and fibrosis involving the skin as well as internal organs such as the vasculature, esophagus, and the respiratory tract. Pulmonary involvement consists most often of interstitial fibrosis and pulmonary vascular disease leading to pulmonary arterial hypertension (PAH). Bronchiectasis is an uncommon pulmonary manifestation of systemic sclerosis. Pulmonary hemorrhage with acute renal failure and diffuse alveolar hemorrhage in the absence of a history of renal involvement or penicillamine intake have rarely been reported in patients with systemic sclerosis.On high resolution CT, evidence of interstitial disease is seen in approximately 90% of patients, the main findings being a fine reticular pattern involving the subpleural regions of the lower lobe. Other common findings include ground-glass opacities, honeycombing, and parenchymal micronodules. The most distinctive pulmonary histologic findings in patients with scleroderma are the vascular changes found in PAH in the absence of significant interstitial fibrosis.There is no strong evidence that any drug alters the course of the two main types of lung disease in systemic sclerosis. This apparent failure of therapy may reflect the fact that pulmonary involvement is usually identified at an established or late stage. It has been suggested that, for fibrosing alveolitis, corticosteroids are most effective if given in combination with cyclophosphamide. In some patients with SSc, PAH has been considered as a major cause of morbidity and mortality. Centrally infused prostacyclin (epoprostenol) and its subcutaneously infused analog treprostinil improve hemodynamics, as well as the quality of life and survival in these patients. Iloprost has also shown a positive effect on PAH in SSc patients. More recently, bosentan, an endothelin receptor antagonist, has proved effective in controlling PAH after 6 months' treatment. Sildenafil has been used as a selective pulmonary vasodilator in SSc patients with isolated PAH. This drug decreased mean pulmonary artery pressure and pulmonary vascular resistance, and increased cardiac output, with much improvement of the physical condition of the patients. Lung transplant can be considered as a last option.Clinicians must be aware of the possibility of lung disease in patients with SSc so that it can be treated as early as possible.

Sclerosing panniculitis is associated with pulmonary hypertension in systemic sclerosis

BACKGROUND

There have been no reports of patients with sclerosing panniculitis and systemic sclerosis (SSc).

OBJECTIVES

To evaluate the incidence of sclerosing panniculitis in patients with SSc, and to investigate the clinical features of such cases.

METHODS

In total, 128 patients with SSc treated at our clinic were investigated retrospectively.

RESULTS

SSc patients with sclerosing panniculitis had pulmonary hypertension (PH), especially isolated PH, at a significantly higher incidence than those without. Among the SSc patients with PH, those with sclerosing panniculitis had pulmonary infarctions at a higher incidence than those without.

CONCLUSIONS

Our results suggest that thrombosis caused by venous hypertension of the leg may be the main cause of PH in patients with SSc and sclerosing panniculitis. Sclerosing panniculitis may be a useful marker of PH in patients with SSc.

The transport of cationic amino acids in human airway cells: expression of system y+L activity and transepithelial delivery of NOS inhibitors

The transport of arginine has been characterized in human airway Calu-3 cells. As assessed with RT-PCR, Calu-3 cells express the genes for several transporters, such as the system y+-related SLC7A1, SLC7A2, and SLC7A4; the system y+L-related SLC7A6, SLC7A7, and SLC3A2; and the system B0,+-related SLC6A14. In polarized Calu-3 cell monolayers, apical arginine influx has a leucine-sensitive, sodium-dependent component and a leucine- and lysine-resistant sodium-independent fraction. At the basolateral membrane, arginine transport was fully sodium-independent and partially inhibited by leucine provided that sodium was present in the extracellular medium. Moreover, extracellular leucine trans-stimulated arginine efflux from the basolateral membrane in the presence, but not in the absence, of sodium. The transepithelial, apical to basolateral, arginine transport strictly depended on the presence of sodium and was markedly inhibited by apical leucine, but significantly trans-stimulated by the neutral amino acid added at the basolateral side. When added at the apical side, the NOS-inhibitors NMMA and NIL, CAA analogs with a free carboxyl group, markedly inhibited the apical arginine influx and the transepithelial flux of the cationic amino acid. The same compounds trans-stimulated basolateral arginine efflux. None of these effects were observed in the presence of the methyl ester analog NAME. The basolateral medium of Calu-3 cell monolayers, obtained after incubation in the presence of the three inhibitors at the apical side, inhibited the production of NO by activated murine macrophages. The inhibitory effect of the Calu-3 cell conditioned medium was time-dependent and markedly higher with NMMA and NIL than with NAME. Moreover, the NOS-inhibitory effect of the medium was significantly enhanced if NMMA and NIL, at the apical side, and basolateral leucine were simultaneously present during the conditioning procedure. These results indicate that 1) human airway epithelial cells express a functional system y+L at the basolateral membrane; 2) in this model, transepithelial arginine transport involves apical influx through system B0,+ and basolateral efflux through system y+L, and 3) the same transporters also perform an efficient transepithelial transport of amino acid-like NOS inhibitors.

Pulmonary hypertension in autoimmune rheumatic diseases

Arterial pulmonary hypertension (PH) might be a complication of some autoimmune rheumatic diseases, specially systemic sclerosis. This form of arterial PH is indistinguishable from primary PH, characterised by the presence of plexiform lesions. Although for many years plexiform lesions have been considered end-stage scarring lesions, they are composed by actively proliferating endothelial cells that share many features with cancer cells. Endothelial cells within plexiform lesions in all forms of arterial PH show a decrease in the expression of vasodilator and anti-proliferative factors, and an increase in the expression of vasoconstrictor and angiogenic and mitogenic factors. These cells also show important alterations in growth and apoptosis key regulatory genes. Plexiform lesions are surrounded by inflammatory cell infiltrates, probably providing cytokines that may contribute to the endothelial cell proliferative process. All these data suggest that arterial PH might be seen as a proliferative endothelial cell process, which would open new therapeutic approaches for this devastating disease.

Plasma levels of endothelin-1, big endothelin-1 and thromboxane following acute pulmonary air embolism

Acute pulmonary air embolism (APAE) was induced in nine piglets by repeated intravenous bolus injection of room air into a large bore central venous catheter at time=0 min so that the mean pulmonary artery pressure (MPAP) was maintained at two times the baseline value for 4 h. Another five animals served as controls. At time=0, 30, 60, 120, 240 min, circulating arterial plasma levels of endothelin-1 (ET-1), its precursor big ET-1, and thromboxane (Tx), were measured by RIA and EIA, respectively, along with hemodynamics and blood gases. The data showed that following APAE, there was a rapid increase in MPAP and a persistent decrease in Pa(O(2)), while the mean arterial blood pressure and cardiac output remained comparable. Plasma levels of ET-1, big ET-1 and Tx were also increased steadily in these first 4 h. These results showed that during APAE, the resulted changes in the pulmonary vascular and airway tones mediated by these potent mediators could explain the observed pulmonary hypertension and the deterioration of gas exchange.

Reduced nitric oxide in sinus epithelium of patients with radiologic maxillary sinusitis and sepsis

Radiologic maxillary sinusitis is an important risk factor for development of bronchopneumonia in mechanically ventilated patients. Nitric oxide produced within the paranasal sinuses is considered to provide an antibacterial environment and to modulate mucociliary clearance function. We hypothesized that a reduced formation of nitric oxide might contribute to the compromised local host defense in radiologic maxillary sinusitis and measured nitric oxide levels directly within maxillary sinuses of septic patients with radiologic maxillary sinusitis (n = 11), whose sinuses were fenestrated to eliminate a possible septic focus. Data were compared with those of patients without airway inflammation (n = 11, control subjects). Despite local inflammation and infection, we found considerably lower maxillary nitric oxide levels than in control subjects (31 +/- 10 versus 2554 +/- 385 parts per billion, mean +/- standard error of the mean, p < 0.001). Consistently, immunohistochemical and in situ hybridization investigations revealed strongly reduced expression of inducible nitric oxide synthase. By applying ultrastructural immunolocalization, we identified cilia and microvilli of the maxillary sinus epithelium as the major nitric oxide production site in control subjects. Our findings provide evidence of markedly reduced nitric oxide production in maxillary sinuses of patients with radiologic maxillary sinusitis and sepsis, implicating impaired local host defense and an increased risk for secondary infections.

Decreased exhaled nitric oxide in sickle cell disease: relationship with chronic lung involvement

A deficiency in airway nitric oxide (NO) could contribute to pulmonary vaso-occlusion in sickle cell disease (SCD). We measured the fractional expired concentration of NO (FE(NO)) by chemiluminescence during a slow vital capacity maneuver against a positive pressure of 16 cm H(2)O at an expiratory flow rate of 50 mL/sec in 44 stable ambulatory adults with SCD and 30 healthy controls. A history of acute chest syndrome was present in 29 patients, and 22 complained of dyspnea. Mean +/- SD FE(NO) was significantly reduced in the SCD group compared with controls (14.8 +/- 8.4 vs. 24.9 +/- 13.5 ppb, P < 0.001). SCD patients with dyspnea had lower FE(NO) than those without dyspnea (10.1 +/- 5.7 vs. 19.6 +/- 8 ppb, P < 0.001) and those with a history of ACS had lower values than those no episodes of ACS (13.0 +/- 8.3 vs. 18.4 +/- 7.6 ppb, P < 0.05). There was a weak correlation between FE(NO) and percent-predicted DLCO (r = 0.4, P = 0.02) among the SCD patients. We conclude that exhaled NO is reduced in adults with SCD, and this may play a role in the pathogenesis of acute chest syndrome and chronic sickle cell lung disease.

Effect of N-acetyl-L-cysteine on peroxynitrite and superoxide anion production of lung alveolar macrophages in systemic sclerosis

Lung macrophages may play a relevant role in oxidative processes producing both superoxide anion (O(2)(-)) and NO. In this view, an antioxidant therapy can be useful in the treatment of systemic sclerosis (SSc) patients. N-Acetylcysteine (NAC) is able to expand natural antioxidant defenses by increasing intracellular gluthatione concentration and it has been proposed as an antioxidant therapy in respiratory distress syndromes. The aim of our study was to determine whether lung macrophages obtained from SSc patient bronchoalveolar lavage (BAL) express the inducible form of nitric oxide synthase (iNOS) and whether NAC can reduce the peroxynitrite (ONOO(-)) and O(2)(-) production of these cells. Alveolar macrophages were isolated from BAL of 32 patients and used for the immunocytochemical determination of iNOS, and the production of ONOO(-) and O(2)(-) was measured by fluorimetric or spectrophotometric methods, respectively. Lung macrophages obtained from SSc patients expressed a higher level of iNOS compared to healthy subject cells. NAC preincubation (5 x 10(-5)M, 24h) significantly reduced (-21%) the ONOO(-) production in formyl Met-Leu-Phe (fMLP)-activated cells and slightly reduced it under resting conditions, whereas NAC preincubation was unable to modify the release of O(2)(-) both in basal condition and in fMLP-stimulated cells. We conclude that since SSc lung macrophages express high levels of iNOS and produce a significant quantity of ONOO(-), NAC administration reduces ONOO(-) production and can be an useful treatment to alleviate SSc symptoms.

Pulmonary hypertension associated with connective tissue disease

Pulmonary arterial hypertension is a life threatening complication of several connective tissue diseases including scleroderma (both diffuse and limited scleroderma, or the CREST syndrome--calcinosis cutis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangectasia), systemic lupus erythomatosis (SLE), mixed connective tissue disease (MCTD), and less commonly, rheumatoid arthritis (RA) and dermatomyositis/polymyositis. This report reviews the occurrence of this complication, potential etiologies, clinical presentation, and treatment options.

Pulmonary arterial hypertension in congenital heart disease

Pulmonary arterial hypertension (PAH) is a recognized complication of congenital systemic to pulmonary arterial cardiac shunts. The prognosis of PAH in this situation is better than primary or other secondary forms of PAH. Our knowledge of the pathophysiology of PAH complicating congenital heart disease has evolved over the past decade. Despite differences in etiology and pathobiology, therapies that have proven successful for primary PAH may benefit this group of patients.

Partitioning of alveolar and conducting airway nitric oxide in scleroderma lung disease

We partitioned exhaled nitric oxide (NO) into alveolar concentration (CA) and conducting airway flux (JNO(air,max)) in scleroderma (SSc) lung disease and hypothesized that CA would be elevated. Twenty patients with SSc, 15 with interstitial lung disease (SSc-ILD) alone, and 5 with pulmonary hypertension (SSc-PH) were compared with 20 control subjects. CA and JNO(air,max) were derived from the slope and y intercept, respectively, of the NO output versus expiratory flow rate ((V).exh) relationship obtained by measuring exhaled NO (FE(NO)) at multiple (V).exh values of 50-200 ml/second. There were no significant differences in FE(NO) at any (V).exh between the SSc group and control subjects. JNO(air,max) was reduced (0.6 +/- 0.1 versus 1.2 +/- 0.2 nl of NO per second; p = 0.01), whereas CA was increased (4.7 +/- 0.5 versus 1.8 +/- 0.2 ppb; p < 0.001) in the SSc group compared with control subjects. No differences were noted between SSc-ILD and SSc-PH. There was a negative correlation between CA and DL(CO) among the patients with SSc (R = -0.66, p = 0.002). We conclude that CA is increased whereas JNO(air,max) is decreased in SSc-ILD and SSc-PH. A reduced diffusing capacity of NO from the alveolar space into the blood could explain the observed increase in CA.

Effect of medroxyprogesterone on pulmonary arterial pressure, exhaled nitric oxide, ECG and arterial blood gases

OBJECTIVES

To evaluate the effect of medroxyprogesterone acetate (MPA) therapy on pulmonary arterial pressure (PAP), exhaled nitric oxide (NO), electrocardiogram (ECG), and on arterial blood gases (ABG).

DESIGN

A double-blind randomized placebo-controlled cross-over trial.

SETTING

University hospital in Turku, Finland.

SUBJECTS

Fourteen postmenopausal women with respiratory impairment.

INTERVENTIONS

A 2-week placebo and a 2-week MPA period (60 mg day -1) followed by 6-week placebo or MPA washout periods.

MAIN OUTCOME MEASURES

The systolic PAP was estimated by Doppler echocardiography. PAP, ECG, NO and ABG were monitored at baseline, after 2-week placebo and MPA periods, and after 3- and 6-week placebo and MPA washout periods.

RESULTS

The mean PaCO2 at baseline was 5.4 +/- 0.6 kPa (mean +/- SD). The average decrease of PaCO2 on MPA was -0.8 +/- 0.3 kPa (P < 0.001) and 0.3 +/- 1.0 kPa (P = 0.007) at the 3-week washout. The mean systolic PAP at baseline was 44.3 +/- 14.5 mm Hg. MPA did not change PAP until the 6-week washout, when the average increase of + 6.9 +/- 19.8 mm Hg (P = 0.002) was observed. No changes occurred in PaO2, exhaled NO or the ECG axes. The PR interval was shorter only on MPA (15.9 +/- 27.0 ms, P = 0.020) whereas the QRS duration remained shorter up to 3-week washout (3.9 +/0 5.5 ms, P = 0.008 and 4.0 +/- 14.3 ms, P = 0.032). The systolic and diastolic BP and the heart rate did not change.

CONCLUSIONS

Despite prolonged decrease in PaCO2, short-term MPA had no effect on exhaled NO and did not decrease systolic PAP in postmenopausal women with respiratory impairment. MPA shortened the PR interval and the QRS duration, the latter effect being sustained at least up to 3 weeks.

Biomarkers of some pulmonary diseases in exhaled breath

Analysis of various biomarkers in exhaled breath allows completely non-invasive monitoring of inflammation and oxidative stress in the respiratory tract in inflammatory lung diseases, including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), bronchiectasis and interstitial lung diseases. The technique is simple to perform, may be repeated frequently, and can be applied to children, including neonates, and patients with severe disease in whom more invasive procedures are not possible. Several volatile chemicals can be measured in the breath (nitric oxide, carbon monoxide, ammonia), and many non-volatile molecules (mediators, oxidation and nitration products, proteins) may be measured in exhaled breath condensate. Exhaled breath analysis may be used to quantify inflammation and oxidative stress in the respiratory tract, in differential diagnosis of airway disease and in the monitoring of therapy. Most progress has been made with exhaled nitric oxide (NO), which is increased in atopic asthma, is correlated with other inflammatory indices and is reduced by treatment with corticosteroids and antileukotrienes, but not (beta 2-agonists. In contrast, exhaled NO is normal in COPD, reduced in CF and diagnostically low in primary ciliary dyskinesia. Exhaled carbon monoxide (CO) is increased in asthma, COPD and CF. Increased concentrations of 8-isoprostane, hydrogen peroxide, nitrite and 3-nitrotyrosine are found in exhaled breath condensate in inflammatory lung diseases. Furthermore, increased levels of lipid mediators are found in these diseases, with a differential pattern depending on the nature of the disease process. In the future it is likely that smaller and more sensitive analyzers will extend the discriminatory value of exhaled breath analysis and that these techniques may be available to diagnose and monitor respiratory diseases in the general practice and home setting.

Low exhaled nitric oxide and a polymorphism in the NOS I gene is associated with acute chest syndrome

Abnormalities of nitric oxide metabolism have been implicated in the pathogenesis of acute chest syndrome in subjects with sickle cell anemia. It is not known whether exhaled nitric oxide levels (FE(NO)) are abnormal in children with a history of the acute chest syndrome (ACS). We compared FE(NO), plasma nitric oxide metabolites (NO(x)), serum arginine and citrulline levels, and the number of AAT repeats in intron 20 of NOS I in subjects with sickle cell disease (SCD) and a history of at least one episode of ACS (ACS(+), n = 13), subjects with SCD and no prior history of ACS (ACS(-), n = 7), and healthy children (HC, n = 6). Mean +/- SD FE(NO) (ppb) was lower in ACS(+) than in ACS(-) and HC: (10.4 +/- 4.3 versus 23.4 +/- 6.1 p = 0.002] and 30.4 +/- 15.8 [p = 0.0001], respectively). Plasma NO(x) (microM) were similar in all three groups (37.3 +/- 19.4, 33.0 +/- 13.2, 44.7 +/- 7.8, respectively). Arginine and citrulline levels (microM) did not differ between ACS(+) and ACS(-) groups. Spirometric data revealed a mildly diminished FEV(1) and FVC in ACS(+) that was statistically different from HC but not ACS(-): (FEV(1) as % of predicted for ACS(+), ACS(-), and HC; 83 +/- 17 versus 87 +/- 16 versus 102 +/- 16, respectively, p < 0.05 between ACS(+) and HC). The level of FE(NO) was significantly associated with the sum of AAT repeats in intron 20 of NOS I gene alleles. The correlation coefficient (r) was 0.62 (p < 0.005). We conclude that FE(NO) levels are significantly reduced in subjects who have a history of ACS and that the FE(NO) levels are significantly correlated with the number of NOS I AAT repeats. FE(NO) is a sensitive marker and may be a predictor of ACS prone children.

Plasma markers of endothelial dysfunction in pulmonary hypertension

STUDY OBJECTIVES

To evaluate and to correlate endothelial cell dysfunction, using recently available plasma markers, with the magnitude of pulmonary artery pressure in patients with severe pulmonary hypertension (PH).

DESIGN

Selected plasma markers of endothelial cell dysfunction were studied: nitric oxide (NO), thrombomodulin, tissue factor pathway inhibitor, and soluble endothelium, leukocyte, and platelet selectins (sE-, sL-, sP-selectins, respectively).

SETTING

Padova University Hospital and Department of Pathology and Pharmacology, Loyola University of Chicago, Chicago, IL.

PATIENTS

Fifteen patients had severe PH (four men and 11 women; mean age, 49.7 +/- 2.9 years: seven patients had primary pulmonary hypertension [PPH] and eight patients had secondary pulmonary hypertension [SPH]), and 20 patients were healthy control subjects.

MEASUREMENT AND RESULTS

In patients with PH, sP- and sE-selectins were elevated, whereas sL-selectin was lower in comparison with the selectin levels in control subjects. However, the differences between patients with PH and control subjects were significant only for sL-selectin (p < 0.0001) and sE-selectin (p < 0.03). The NO level was significantly lower in patients with PH compared with the NO level in control subjects (p < 0.01). No difference in tissue factor pathway inhibitor level was noted between control subjects and patients with PH. Only a weak correlation was found between thrombomodulin plasma levels and magnitude of systolic pulmonary artery pressure (r = -0.528, p < 0.05).

CONCLUSIONS

Our data are in keeping with the evidence for significant endothelial cell dysfunction in patients with PH and the need for chronic anticoagulation believed to increase survival in these patients. In addition, these data seem to suggest a need for newer agents that are able to increase the antithrombotic endothelial function.

Exhaled nitric oxide in patients with PiZZ phenotype-related alpha1-anti-trypsin deficiency

There is no report of exhaled NO (eNO) in subjects with different phenotypes of alpha1-anti-trypsin (AAT) deficiency. Exhaled nitric oxide was evaluated by means of single-breath chemiluminescence analysis (fractional exhaled concentration at the plateau level [plFE(NO)]) in 40 patients with AAT deficiency. Patients were divided according to the protease inhibitor (Pi) phenotype: PiMZ/MS, n = 25; PiSZ n = 6; PiZZ, n = 9. Nineteen healthy subjects served as controls. Levels of eNO in PiZZ patients were also compared with those of subjects, without AAT deficiency (PiMM), matched for diagnosis, sex, age, smoking habit and forced expiratory volume in 1 sec (FEV1). In AAT deficiency subjects airway hyper-responsiveness to methacholine (PD20 FEV1) was also assessed. plFE(NO) was significantly lower in the PiZZ group (4.5+/-1.4 ppb) than in matched PiMM subjects (8.2+/-3.8 ppb), in healthy controls (9.3+/-2.8 ppb) and in patients of other phenotypes. Dynamic lung volumes and DL(CO) were significantly lower in PiZZ than in other AAT-deficient patients. Bronchial hyper-responsiveness was not different among AAT phenotypes. These results suggest that eNO may be significantly reduced in PiZZ as compared to healthy control subjects and to AAT subjects with other phenotypes, independent of the level of airway obstruction. Whether, at least potentially, eNO may be considered as an early marker of lung involvement in AAT deficiency must be confirmed with studies on larger number of subjects.

Exhaled Nitric Oxide Is Elevated in Patients With Progressive Systemic Sclerosis Without Interstitial Lung Disease

BACKGROUND

Progressive systemic sclerosis (PSS) is a multisystem disorder of unknown etiology. Interstitial lung disease (ILD) is a major cause of mortality in this condition, and a major challenge in this regard is to identify parameters that would predict the onset or progression of ILD in patients with PSS. Abnormal cellularity of BAL fluid (BALF) has been demonstrated in patients with PSS without ILD.

STUDY OBJECTIVES

We investigated exhaled nitric oxide (NO) as a noninvasive marker of pulmonary inflammation in patients with PSS with and without clinical and radiologic evidence of ILD. This was compared with the cellularity of BALF. Our hypothesis was that exhaled NO was elevated in patients with PSS without ILD who had abnormal BALF cellularity.

SETTING

Pulmonology and rheumatology units of a university-based, tertiary referral hospital in Durban, South AFRICA:

STUDY METHODS

Exhaled NO was measured using a chemiluminescence analyzer in 12 patients with PSS and ILD and in 12 patients without clinical or radiologic evidence of ILD and in 30 healthy control subjects. BAL was performed in patients with PSS with and without the presence of ILD and in six healthy control subjects.

RESULTS

Subclinical inflammation was confirmed by increased inflammatory cell counts in BALF from patients with PSS without ILD. Exhaled NO (mean [SEM]) was elevated in patients with PSS without ILD at 9.6 (0.7) parts per billion (ppb) compared to patients with PSS and ILD at 6.2 (0.6) ppb (p < 0.001) and healthy control subjects at 6.3 (0.2) ppb (p < 0.001).

CONCLUSION

Exhaled NO may therefore be an important noninvasive surrogate marker of inflammation in patients with PSS without ILD.

Role of exhaled nitric oxide in asthma

Nitric oxide (NO), an evanescent atmospheric gas, has recently been discovered to be an important biological mediator in animals and humans. Nitric oxide plays a key role within the lung in the modulation of a wide variety of functions including pulmonary vascular tone, nonadrenergic non-cholinergic (NANC) transmission and modification of the inflammatory response. Asthma is characterized by chronic airway inflammation and increased synthesis of NO and other highly reactive and toxic substances (reactive oxygen species). Pro- inflammatory cytokines such as TNFalpha and IL-1beta are secreted in asthma and result in inflammatory cell recruitment, but also induce calcium- and calmodulin-independent nitric oxide synthases (iNOS) and perpetuate the inflammatory response within the airways. Nitric oxide is released by several pulmonary cells including epithelial cells, eosinophils and macrophages, and NO has been shown to be increased in conditions associated with airway inflammation, such as asthma and viral infections. Nitric oxide can be measured in the expired air of several species, and exhaled NO can now be rapidly and easily measured by the use of chemiluminescence analysers in humans. Exhaled NO is increased in steroid-naive asthmatic subjects and during an asthma exacerbation, although it returns to baseline levels with appropriate anti-inflammatory treatment, and such measurements have been proposed as a simple non-invasive method of measuring airway inflammation in asthma. Here the chemical and biological properties of NO are briefly discussed, followed by a summary of the methodological considerations relevant to the measurement of exhaled NO and its role in lung diseases including asthma. The origin of exhaled NO is considered, and brief mention made of other potential markers of airway inflammation or oxidant stress in exhaled breath.

Differential expression of nitric oxide by dermal microvascular endothelial cells from patients with scleroderma

Vascular abnormalities in scleroderma are fundamental to the pathogenesis of this disease. The objective of this study was to characterize dermal microvascular endothelial cells (DMEC) isolated from scleroderma patients with respect to growth and expression of the constitutive form of endothelial nitric oxide synthase (eNOS). DMEC from patients with both systemic sclerosis (SSc) and localized scleroderma (Loc Scl) contained small intact microvascular structures in contrast to single cell isolations obtained from control skin. Immunoaffinity selection on anti-PECAM-1 beads yielded pure populations of DMEC expressing normal markers. While the morphology and initial growth of SSc DMEC closely paralleled control cells, the growth of SSc DMEC decreased with time in culture (doubling time of 3 days vs. 5 days). Expression of ecNOS mRNA was reduced in both Loc Scl and SSc as shown by semi-quantitative RT-PCR (p < 0.001). Western blots showed variable but generally lower ecNOS protein levels and decreased levels of nitrogen oxides in media were found from both SSc and Loc Scl relative to control cells. The results indicate an intrinsic defect in the mechanism of nitric oxide production in DMEC isolated from scleroderma patients and suggest its possible involvement in the pathophysiology of scleroderma.

Novel therapy in the treatment of scleroderma

While the biology of the pathogenesis of scleroderma is continually being better understood, there still is no single agent or therapeutic combination that has a clear impact on the disease process. Traditional medications (colchicine, potassium aminobenzoate (potaba), D-penicillamine) are disappointing in clinical practice despite anecdotal evidence of benefit. Furthermore, the most popular traditional drug, D-penicillamine, failed to clearly show benefit when tested in a well-designed clinical trial comparing conventional high dose with a very low dose (125 mg po. every other day [corrected]) [1]. Currently, most success in managing scleroderma and improving quality of life is secondary to organ-specific therapy, such as management of a renal crisis with an ACE inhibitor, treatment of Raynaud's phenomenon with calcium channel blockers, or control of serious gastrointestinal reflux disease with a proton pump inhibitor. In this review we will focus on novel therapies that are currently being tested in the treatment of scleroderma and have the potential of modifying the disease process and overall clinical outcome. We have attempted to review the rationale for each agent, recognising that its true biological effect will only be determined in clinical trials.

Increased nitric oxide in exhaled air in patients with rheumatic heart disease

BACKGROUND

Endogenous production of nitric oxide and its presence in exhaled air was observed in humans. Prior studies have yielded contrasting information about the production of nitric oxide in patients with heart failure.

AIMS

The aim of this study was to measure nitric oxide in the exhaled air of patients with chronic rheumatic heart disease with and without pulmonary hypertension.

METHODS

Seventy-four patients (6 patients had isolated mitral stenosis; 13 patients had combined mitral stenosis and mitral regurgitation; 1 patient had isolated mitral regurgitation; 54 patients had combined mitral and aortic valve disease) and 27 healthy subjects were entered in the study. The nitric oxide concentration in exhaled air was determined with a chemiluminescence analyser. Echocardiography was performed in all patients to assess the severity of the valve disease and for the measurement of pulmonary artery pressure.

RESULTS

The level of exhaled nitric oxide was significantly greater in patients with rheumatic heart disease than in controls. The value of nitric oxide concentration in exhaled air was significantly increased in patients with pulmonary hypertension, as compared with patients who had normal pulmonary artery systolic pressure.

CONCLUSION

We found increased nitric oxide in the exhaled air in patients with rheumatic heart disease, especially in those with pulmonary hypertension, compared with healthy patients.

Nitric oxide in the nasal airway: a new dimension in otorhinolaryngology

The discovery that the gas nitric oxide (NO) is an important signaling molecule in the cardiovascular system earned its Nobel prize in 1998. NO has since been found to play important roles in a variety of physiologic and pathophysiologic processes in the body including vasoregulation, hemostasis, neurotransmission, immune defense, and respiration. The surprisingly high concentrations of NO in the nasal airway and paranasal sinuses has important implications for the field of otorhinolaryngology. NO provides a first-line defense against micro-organisms through its antiviral and antimicrobial activity and by its upregulation of ciliary motility. Nasal treatments such as polypectomy, sinus surgery, removal of hypertrophic adenoids and tonsils, and treatment of allergic rhinitis may alter NO output and, therefore, the microbial colonization of the upper airways. Nasal surgery aimed at relieving nasal obstruction may do the same but would also be expected to improve pulmonary function in patients with asthma and upper airway obstruction. NO output rises in a number of conditions associated with chronic airway inflammation, but not all of them. Concentrations are increased in asthma, allergic rhinitis, and viral respiratory infections, but reduced in sinusitis, cystic fibrosis, primary ciliary dysfunction, chronic cough, and after exposure to tobacco and alcohol. Therefore, NO, similar to several other inflammatory mediators, probably subserves different functions as local conditions dictate. At present, it seems that the measurement of NO in the upper airway may prove valuable as a simple, noninvasive diagnostic marker of airway pathologies. The objective of this review is to highlight some aspects of the origin, physiology, and functions of upper airway NO, and to discuss the particular methodological problems that result from the complex anatomy.

Increased nitric oxide production in patients with systemic sclerosis

Nitric oxide (NO, nitrogen monoxide) is a messenger molecule whose synthesis can be induced by proinflammatory cytokines. Increased production of NO has been reported in various inflammatory and autoimmune diseases. We studied serum nitrite and citrulline as surrogate markers for NO production in patients with systemic sclerosis (SSc) and looked for correlation with extent of disease, disease duration, age, and systemic involvement. Thirty-four patients were studied against 20 controls. The nitrite levels were significantly higher in the disease group (1588.4 +/- 998.2 nmol/ml compared to 327.8 +/- 137.7 nmol/ml; P < 0.001). The citrulline levels of the disease group were also significantly higher (5490.1 +/- 2518.3 nmol/ml compared to 3264.5 +/- 2509.7 nmol/ml in the controls; P = 0.005). There was no significant difference among limited and diffuse subgroups. There was no significant difference in patients with or without arthritis or interstitial lung disease or with other systemic involvement. On multivariate analysis there was a trend toward a rising level of nitrite with worsening lung functions (P = 0.07). Hence, there is evidence of increased NO production in patients with SSc. There is no difference between NO levels in disease subgroups or those with systemic involvement.

Clinical and laboratory features of scleroderma patients with pulmonary hypertension

OBJECTIVE

Pulmonary hypertension (PH) is a frequent cause of death in patients with systemic sclerosis (SSc). In this study, we examined the occurrence of PH and investigated the clinical and laboratory features of SSc patients with PH.

METHODS

A cross-sectional study of 125 Japanese patients with SSc was conducted using Doppler echocardiography, other multiple cardiopulmonary tests, and laboratory examination.

RESULTS

PH (systolic pressure >40 mmHg) was diagnosed in 20 patients (16%) by Doppler echocardiography. In the six patients who had secondary pulmonary hypertension (SPH), PH was due to severe pulmonary fibrosis; 14 patients had isolated pulmonary hypertension (IPH). An elevated erythrocyte sedimentation rate (ESR) and increased immunoglobulin G (IgG) were found in a significantly greater proportion of the patients with PH than in those without PH. The incidence of pitting scars/ulcers was significantly greater in the patients with SPH than in those without PH.

CONCLUSION

Elevated ESR and increased IgG were common features of scleroderma patients with PH, and scleroderma patients with SPH were inclined to have pitting scars/ulcers.

Use of nitric oxide for decompensated right ventricular failure and circulatory shock after cardiac arrest

We describe a case of peri-operative cardiac arrest, severe right ventricular failure and pulmonary hypertension in a 60-yr-old woman with interstitial pulmonary fibrosis. Inhaled nitric oxide therapy rapidly improved arterial oxygenation and haemodynamic variables, allowing recovery and weaning from mechanical ventilation. Subsequently, the patient was discharged from the cardiac intensive care unit.

Production of endogenous nitric oxide in chronic obstructive pulmonary disease and patients with cor pulmonale. Correlates with echo-Doppler assessment

Exhaled nitric oxide (NO) production in stable chronic obstructive pulmonary disease (COPD) has been loosely related to the severity of illness, being significantly reduced in the most severe cases. Pulmonary hypertension is associated with lower NO output from the lung. In this study expired NO was measured in patients with severe stable COPD with or without cor pulmonale (CP). Echocardiographic estimates of right heart function, lung function, diffusion capacity, respiratory muscle strength, and arterial blood gases were obtained in 34 consecutive patients with stable COPD (mean age, 68 +/- 7 yr). Expired NO was measured by chemiluminiscence to obtain fractional exhaled concentrations at peak (FENOp) and at plateau (FENOpl) points of the single-breath curve and resting NO output (V NO). All measurements of expired NO output, FENOp, FENOpl and V NO showed a negative correlation with both systolic pulmonary artery pressure (Pspa) (r = -0.51, -0.63, and -0.63, respectively, p < 0.01 for all) and right ventricle wall dimension (r = -0.41, -0.59, and -0.43, respectively, p < 0.05 for all), but not with any measurement of lung function. When the patients were divided according to the Pspa using a cutoff limit of 35 mm Hg, those subjects with CP showed lower FENOp (13.2 +/- 4.0 versus 36.7 +/- 30.8 ppb, p < 0.05), FENOpl (5.7 +/- 1.9 versus 8.9 +/- 4.7 ppb, p < 0.05), and V NO (69. 2 +/- 5.6 versus 107.6 +/- 14.6 nl/ min, p = 0.02) than did those with a normal resting Pspa. NO production from the airways was significantly lower and inversely related to development of CP in patients with severe COPD. Impaired endothelial release may account for the reduced levels of expired NO.

Exhaled nitric oxide in high-altitude pulmonary edema: role in the regulation of pulmonary vascular tone and evidence for a role against inflammation

High-altitude pulmonary edema (HAPE) is a life-threatening condition occurring in predisposed subjects at altitudes above 2,500 m. It is not clear whether, in addition to hemodynamic factors and defective alveolar fluid clearance, inflammation plays a pathogenic role in HAPE. We therefore made serial measurements of exhaled pulmonary nitric oxide (NO), a marker of airway inflammation, in 28 HAPE-prone and 24 control subjects during high-altitude exposure (4,559 m). To examine the relationship between pulmonary NO synthesis and pulmonary vascular tone, we also measured systolic pulmonary artery pressure (Ppa). In the 13 subjects who developed HAPE, exhaled NO did not show any tendency to increase during the development of lung edema. Throughout the entire sojourn at high altitude, pulmonary exhaled NO was roughly 30% lower in HAPE-prone than in control subjects, and there existed an inverse relationship between Ppa and exhaled NO (r = -0.51, p < 0.001). These findings suggest that HAPE is not preceded by airway inflammation. Reduced exhaled NO may be related to altered pulmonary NO synthesis and/or transport and clearance, and the data in our study could be consistent with the novel concept that in HAPE-prone subjects, a defect in pulmonary epithelial NO synthesis may contribute to exaggerated hypoxic pulmonary vasoconstriction and in turn to pulmonary edema.

Acute hypoxia and reoxygenation impairs exhaled nitric oxide release and pulmonary mechanics

OBJECTIVE

Changes in exhaled nitric oxide levels often accompany conditions associated with elevated pulmonary vascular resistance and altered lung mechanics. However, it is unclear whether changes in exhaled nitric oxide reflect altered vascular or bronchial nitric oxide production. This study determined the effects of acute hypoxia and reoxygenation on pulmonary mechanics, plasma nitrite levels, and exhaled nitric oxide production.

METHODS

Ten piglets underwent 90 minutes of hypoxia (fraction of inspired oxygen = 12%), 1 hour of reoxygenation on cardiopulmonary bypass, and 2 hours of recovery. Five additional animals underwent bypass without hypoxia. Exhaled nitric oxide, plasma nitrite levels, and pulmonary mechanics were measured.

RESULTS

Exhaled nitric oxide decreased to 36% of baseline by end hypoxia (34 +/- 14 vs 12 +/- 9 ppb, P =.005) and declined further to 20% of baseline at end recovery (7 +/- 6 ppb). Aortic nitrite levels decreased from baseline during hypoxia (from 102 +/- 13 to 49 +/- 7 micromol/L, P =.05) but returned to baseline during recovery. Pulmonary arterial nitrite also decreased during hypoxia (from 31.4 +/- 7.8 to 22.9 +/- 9.5 micromol/L, P =.04) and returned to baseline at end recovery. Decreased production of exhaled nitric oxide was associated with impaired gas exchange (alveolar-arterial gradient = 32 mm Hg at baseline and 84 mm Hg at end recovery), decreased pulmonary compliance (6.6 +/- 0.9 mL/cm H(2)O at baseline, 5.0 +/- 0.7 mL/cm H(2)O at end hypoxia, and 5.4 +/- 0.7 mL/cm H(2)O at end recovery), and increased inspiratory airway resistance (41 +/- 4 cm H(2)O. L(-1). s(-1) at baseline, 56 +/- 4.9 cm H(2)O. L(-1). s(-1) at end hypoxia, and 50 +/- 5 cm H(2)O. L(-1). s(-1) at end recovery).

CONCLUSIONS

A decrease in exhaled nitric oxide persisted after hypoxia, and plasma nitrite levels returned to baseline on reoxygenation, indicating that alterations in exhaled nitric oxide during hypoxia-reoxygenation might be unrelated to plasma nitrite levels. Furthermore, decreased exhaled nitric oxide corresponded with altered pulmonary mechanics and gas exchange. Reduced exhaled nitric oxide after hypoxia-reoxygenation might reflect bronchial epithelial dysfunction associated with acute lung injury.

Endogenous nitric oxide in patients with chronic heart failure (CHF): relation to functional impairment and nitrate-containing therapies

We assessed the levels of exhaled nitric oxide (eNO) in patients with chronic heart failure (CHF) according to the functional impairment and the use of nitrate-containing agents. Forty patients (age 55+/-9 years) were classified according to the NYHA classes I-II (n=18, group 1) and classes III-IV (n=22, group 2), and to the use of nitrate-containing drugs (Nitrate+, Nitrate-). Twenty-two healthy age-related subjects served as controls (group 3). Respiratory function, symptom-limited incremental cycloergometry and resting eNO concentration at peak (FENOp) or plateau (FENOpl) of the single-breath exhalation curve were assessed in all subjects. FENOpl was significantly lower in patients than in controls (7.8+/-2.7 and 10.6+/-2.8 ppb, respectively, P<0.005) and lower in most severe CHF patients (7.1+/-2.6 and 8.8+/-2.7 ppb in group 2 and group 1, respectively, P<0.05). A significant correlation between peak V'O(2), Watts and FENOpl (r=0.42, P<0.013 and r=0.46, P=0.008, respectively) was found. Independent of NYHA class, Nitrate+ showed higher FENOp levels than Nitrate- patients (36.9+/-15.7 vs. 28. 1+/-15.1 ppb, P<0.05). Resting eNO was lower in the most compromised CHF patients and was significantly related to exercise capacity. Nitrate-containing agents might influence the levels of eNO in these patients.

Exhaled nitric oxide and exercise in stable COPD patients

STUDY OBJECTIVE

To evaluate exhaled nitric oxide (eNO) during exercise in patients with stable COPD.

SETTING

Outpatient evaluation in a rehabilitation center.

PATIENTS

Eleven consecutive male patients with stable COPD (age, 65 +/- 6 years; FEV(1), 56 +/- 10% predicted). Eight healthy (six men; age, 51 +/- 16 years) nonsmoking, nonatopic volunteers served as control subjects.

METHODS

In each subject, a symptom-limited cycle ergometry test was performed by monitoring eNO with the tidal-breath method to assess eNO concentration (FENO) and output (VNO) at rest, peak exercise, and recovery time.

RESULTS

Resting FENO (9.8 +/- 5.1 and 14.1 +/- 6.3 parts per billion, respectively) and VNO (4.2 +/- 2.0 and 5.9 +/- 3.4 nmol/min, respectively) were lower, although not significantly, in COPD patients than in control subjects. In both groups, FENO significantly decreased whereas VNO significantly increased during exercise. Both variables returned to baseline during the recovery time. Peak exercise VNO, but not FENO, was significantly lower in COPD patients than in control subjects (7.9 +/- 5.4 and 12.7 +/- 6.0 nmol/min, respectively, p < 0.05). The rise in VNO was weakly correlated to oxygen consumption VO(2)) both in control subjects (r = 0.31, p = 0. 002) and in COPD patients (r = 0.22, p = 0.03). FENO showed an inverse correlation to VO(2) in both groups (r = -0.53, p = 0.000; r = -0.31, p = 0.003 in control subjects and COPD patients, respectively).

CONCLUSIONS

In patients with mild and moderate COPD, eNO during exercise parallels that observed in normal control subjects. VNO, but not FENO, is significantly reduced at peak exercise in COPD patients as compared with control subjects. The long-term effects of exercise training on eNO has to be evaluated by further studies.

Additive effects of inhaled nitric oxide and intravenous milrinone in experimental pulmonary hypertension

OBJECTIVE

To determine whether inhaled nitric oxide (IN0) and intravenous milrinone have additive pulmonary vasodilator effects in a rat model of pulmonary hypertension.

DESIGN

Prospective, experimental study.

SETTING

Animal laboratory of a university medical center.

SUBJECTS

Male New Zealand White rabbits.

INTERVENTIONS

Anesthetized rabbits were mechanically ventilated and instrumented for measurement of systemic mean arterial pressure (MAP), pulmonary artery pressure (PAP), left atrial pressure, and cardiac output (CO). After baseline measurements, the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (30 mg/kg iv) was administered. Pulmonary hypertension was produced by the continuous infusion of U46619, a thromboxane A2 mimetic. INO (40 ppm) was added to the inspired gas, and hemodynamic measurements were obtained before and after INO. Milrinone was administered sequentially as a 30-mg/kg bolus followed by a 3-microg/kg/min infusion, a 100-mg/kg bolus followed by a 10-microg/kg/min infusion, and a 300-mg/kg bolus followed by a 30-microg/kg/min infusion (M3). Hemodynamic measurements were obtained with and without INO at each dose of milrinone.

MEASUREMENTS AND MAIN RESULTS

During U46619-induced pulmonary hypertension, INO decreased PAP and pulmonary vascular resistance (PVR) but did not affect MAP, systemic vascular resistance (SVR), or CO. Milrinone dose dependently decreased PAP, PVR, MAP, and SVR and increased CO. At each dose of milrinone, INO further decreased PVR but not SVR. M3 decreased PVR 49%, and the addition of INO decreased PVR an additional 19% so that PAP and PVR decreased to baseline values.

CONCLUSIONS

Milrinone and INO both decrease pulmonary hypertension individually, and the combination produces additive effects. Combination therapy may produce potent and selective pulmonary vasodilation during the treatment of pulmonary hypertension.

[Pulmonary involvement in systemic scleroderma. Part II. Isolated pulmonary arterial hypertension, bronchopulmonary cancer, alveolar hemorrhage]

INTRODUCTION

Pulmonary interstitial fibrosis is the most frequent cause of lung disease in systemic sclerosis. However, other pulmonary complications exist, including lung cancer, alveolar hemorrhage, and in particular isolated pulmonary arterial hypertension, which is still considered the bête noire as regards this disease.

CURRENT KNOWLEDGE AND KEY POINTS

The prevalence of pulmonary arterial hypertension has been reported to range from 5 to 60% in cases of systemic sclerosis; isolated pulmonary arterial hypertension has been principally observed in subjects with a ten-year history of limited forms of the disease. As the patient remains asymptomatic for a long period, with nonspecific respiratory clinical manifestations, the diagnosis is made at a much later stage in the course of the disease. The diagnostic method of choice is echocardiography-doppler, which should be performed during the preliminary investigation, and at follow-up. The prognosis is poor, and patient survival rate at 2 years after onset of symptoms amounts to 40%. To date, no curative therapy for pulmonary arterial hypertension has yet been found.

FUTURE PROSPECTS AND PROJECTS

A knowledge of the mechanisms involved in the development of isolated pulmonary arterial hypertension is essential to the determination of new and relevant therapeutic strategies. Vasodilatory treatment, notably calcium channel blockers, prostacyclin and analogs such as iloprost, may be effective at an early stage of the disease before the appearance of permanent vascular damage.

Exhaled nitric oxide is increased in active fibrosing alveolitis

STUDY OBJECTIVES

Interstitial inflammation is a major aggravating factor in fibrosing lung disease associated with scleroderma (FASSc) and cryptogenic fibrosing alveolitis (CFA). Exhaled nitric oxide (NO) production is increased in asthma and bronchiectasis and reflects the degree of inflammation. We investigated whether measuring levels of exhaled NO is valuable in assessing disease activity in patients with CFA and patients with FASSc.

MEASUREMENTS AND RESULTS

NO levels were measured in 11 patients with CFA (mean age +/- SEM, 58 +/- 12 years old; 5 were male) and 17 patients with FASSc (mean age, 48 +/- 9 years old; 5 were male), and they were compared to BAL cell counts and lung function. Patients with CFA and FASSe had elevated NO levels (11.2 +/-1.0 parts per billion [ppb] and 9.8 +/- 1.0 ppb, respectively; p > 0.05), whereas in a group of 13 nonsmoking normal subjects, the NO levels were not elevated (6.9 +/- 0.5 ppb; p < 0.05). Patients with FASSc (n = 8) who had active BAL (defined as either lymphocytes > 14%, neutrophils > 4%, or eosinophils > 3%) had significantly higher NO levels (13.2 +/- 1.8 ppb), and neutrophil (16.5 +/- 4.0%) and lymphocyte (26.8 +/- 3.4%) BAL cell counts than did patients with FASSc who had inactive BAL (6.7 +/- 1.2 ppb; 1.3 +/- 1.0% and 7.5 +/- 1.3%, respectively; p < 0.05). There was a significant correlation between exhaled NO and lymphocyte cell count in patients with FASSc (r = 0.58; p < 0.05). All patients with CFA had active BAL; however, those treated with corticosteroids (12.9 +/- 1.0% ppb, p < 0.05) had lower NO levels (9.0 +/- 1 ppb) and higher BAL lymphocyte cell couits (16.6 +/- 2.0%) than did those not treated with corticosteroids (7.2 +/- 1.7%; p < 0.05).

CONCLUSIONS

We conclude that exhaled NO may be a useful addition to BAL cell counts in disease monitoring.

Recognition and management of pulmonary hypertension

Pulmonary hypertension (mean pulmonary arterial pressure > 20mm Hg at rest or > 30mm Hg during exercise) occurs (i) as primary pulmonary hypertension (no known underlying cause), (ii) as persistent pulmonary hypertension of the newborn or (iii) secondary to a variety of lung and cardiovascular diseases. In the last 10 to 15 years there have been significant advances in the medical management of this debilitating and life-threatening disorder. The main drugs in current use are anticoagulants (warfarin, heparin) and vasodilators, especially oral calcium antagonists, intravenous prostacyclin (prostaglandin I2; epoprostenol) and inhaled nitric oxide. Calcium antagonists, (e.g. nifedipine, diltiazem) are used chiefly in primary pulmonary hypertension. They are effective in patients who give a pulmonary vasodilator response to an acute challenge with a short acting vasodilator (e.g. prostacyclin, nitric oxide or adenosine), and are used in doses greater than are usual in the treatment of other cardiovascular disorders. Prostacyclin, given by continuous intravenous infusion, is effective in patients even if they do not respond to an acute vasodilator challenge. The long term benefit in these patients is thought to reflect the antiproliferative effects of the drug and/or its ability to inhibit platelet aggregation. It is used either as long term therapy or as a bridge to transplantation. Inhaled nitric oxide, which is used mainly in persistent pulmonary hypertension of the newborn, has the particular benefit of being pulmonary selective, due to its route of administration and rapid inactivation. Anticoagulants have a specific role in the treatment of pulmonary thromboembolic pulmonary hypertension and are also used routinely in patients with primary pulmonary hypertension. Nondrug treatments for pulmonary hypertension include (i) supplemental oxygen (> or = 15 h/day), which is the primary therapy in patients with pulmonary hypertension secondary to chronic obstructive pulmonary disease and (ii) heart-lung or lung transplantation, which nowadays is regarded as a last resort. Different types of pulmonary hypertension require different treatment strategies. Future advances in the treatment of pulmonary hypertension may come from the use of drug combinations, the development of new drugs, such as endothelin antagonists, nitric oxide donors and potassium channel openers, or the application of gene therapy.