Exhaled nitric oxide in systemic sclerosis: relationships with lung involvement and pulmonary hypertension.
OBJECTIVE
To measure nitric oxide (NO) concentration in exhaled air of patients with systemic sclerosis (SSc) and to investigate its relationships with lung involvement, complicated or not by pulmonary hypertension (PH).


METHODS
Exhaled NO was measured by chemiluminescence in 47 patients with SSc (16 with PH) and in 30 controls. All the patients underwent Doppler echocardiography to assess pulmonary artery pressure (PAP), lung function tests, and thin section computed tomographic scans of the lung to quantify the extent of fibrosing alveolitis.


RESULTS
Exhaled NO levels were higher in patients with SSc (16.6 +/- 9.1 ppb), particularly those with interstitial lung disease (ILD) (18.3 +/- 10.4 ppb), compared to controls (9.9 +/- 2.9 ppb; p < 0.0001). In patients with PH, exhaled NO was less than in patients without PH (10.7 +/- 5.9 vs 19.6 +/- 9 ppb, respectively; p < 0.001), and patients with PH without ILD had even lower exhaled NO than patients with PH and ILD (6.6 +/- 1.1 vs 12.6 +/- 6.3 ppb; p = 0.004). There was an inverse correlation between PAP and exhaled NO (r = 04).53, p = 0.004). Exhaled NO was not correlated to age, disease duration, current therapy, or form of disease (limited or diffuse).


CONCLUSIONS
The increased concentration of exhaled NO in patients with SSc may reflect respiratory tract inflammation. The relatively low value of exhaled NO in patients with PH and the negative correlation between PAP and exhaled NO suggest the important role of NO in regulating pulmonary vascular resistance in patients with SSc.
Department of Scienze Biomediche e Oncologia Umana, University of Torino, and Ospedale Molinette Torino, Italy.
G
G
Rolla
P
P
Colagrande
E
E
Scappaticci
G
G
Chiavassa
L
L
Dutto
S
S
Cannizzo
C
C
Bucca
M
M
Morello
S
S
Bergerone
D
D
Bardini
A
A
Zaccagna
P
P
Puiatti
C
C
Fava
G
G
Cortese
D000328:Adult; D000368:Aged; D018618:Echocardiography, Doppler, Color / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D012129:Respiratory Function Tests / Q000706:statistics & numerical data; D012143:Respiratory Physiological Phenomena; D012595:Scleroderma, Systemic / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data
D009569:Nitric Oxide