L-arginine plasma levels and severity of idiopathic pulmonary arterial hypertension.
BACKGROUND
Idiopathic pulmonary arterial hypertension (iPAH) is a rare disease of unknown aetiology characterized by a poor prognosis. Impairment of nitric oxide (NO) synthesis or NO-induced vasorelaxation has been suspected to play a role in the development of iPAH. This study was performed to investigate possible correlations between the plasma levels of the NO-related aminoacids L-arginine, L-citrulline and N-hydroxy-L-arginine (L-NHA) and the severity of iPAH.


METHODS
In twelve iPAH patients hemodynamics were measured by right heart catheterization, and plasma levels of L-arginine, L-citrulline and L-NHA were determined in blood samples from the pulmonary artery, peripheral artery and peripheral vein by high-performance liquid chromatography analysis. In eight of twelve patients a six minute walk test was performed.


RESULTS
Plasma levels of L-arginine strongly correlated to right atrial pressure, cardiac output, cardiac index, mixed-venous oxygen saturation, six minute walk data and NYHA functional class at all sites of blood sampling (p < 0.05).


CONCLUSIONS
The results suggest a possible role of the NO precursor L-arginine in the pathogenesis of iPAH.
University Clinic Dresden, Medical Clinic III, Dept. of Vascular Medicine, Germany. Beyer.Jan@uniklinikum-dresden.de
J
J
Beyer
M
M
Kolditz
R
R
Ewert
C
C
Rubens
C
C
Opitz
S
S
Schellong
G
G
Hoeffken
M
M
Halank
D000328:Adult; D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives / Q000097:blood*; D015415:Biomarkers; D001794:Blood Pressure; D006328:Cardiac Catheterization; D002851:Chromatography, High Pressure Liquid; D002956:Citrulline / Q000097:blood; D015331:Cohort Studies; D005080:Exercise Test; D005260:Female; D006439:Hemodynamics; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011651:Pulmonary Artery / Q000503:physiopathology*; D012720:Severity of Illness Index
D015415:Biomarkers; D002956:Citrulline; D001120:Arginine