Differences in plasma L-arginine and dimethylarginines in diagnosis and treatment of pulmonary arterial hypertension: a prospective observational study
(English)Manuscript (preprint) (Other academic)
Introduction Pulmonary arterial hypertension (PAH) is a life-threatening condition, characterized by an imbalance in vasoactive substances and remodelling of pulmonary vasculature. Asymmetric dimethylarginine (ADMA) inhibits the enzyme nitric oxide synthase, which generates nitric oxide (NO), a molecule causing smooth muscle cell relaxation. Our aim was to investigate the plasma concentrations of ADMA, symmetrical dimethylarginine (SDMA), L-arginine, L-ornithine and L- citrulline at diagnosis and during PAH-specific treatment in patients with PAH compared to patients with left heart failure (LVHF) and healthy subjects.
Methods This is an observational, prospective multicentre study of 21 PAH patients. For comparison 14 patients with LVHF and 27 healthy subjects were investigated. Blood samples were collected and ADMA, SDMA, L-arginine, L-ornithine and L-citrulline were analysed with liquid chromatography – tandem mass spectrometry (LC-MS/MS).
Results Baseline plasma concentrations of ADMA and SDMA were higher whereas the L-arginine concentrations and L-arginine/ADMA ratio were lower in PAH patients compared to healthy subjects (p<0.001). Patients with PAH had lower L-arginine concentration than patients with LVHF (p<0.05). WHO functional class and six minutes walking distance (6MWD) correlated to L-arginine and L- arginine/ADMA in PAH at baseline (p<0.05). At follow-up, patients on mono- or combination therapy with endothelin receptor antagonists (ERA) had lower ADMA levels than patients without ERA (p<0.05). In contrast, patients on phosphodiesterase type-5 inhibitors (PDE5-inhibitors) had higher ADMA levels compared to patients without PDE5-inhibitor treatment (p<0.05).
Conclusion Concentrations of L-arginine were decreased and dimethylarginines were increased in PAH compared to healthy subjects. L-arginine was decreased in PAH compared to LVHF. L- arginine/ADMA ratio correlated to WHO functional class and L-arginine and L-arginine/ADMA ratio correlated to 6MWD. PAH-specific treatment influences the levels of L-arginine and dimethylarginines.
pulmonary arterial hypertension, dimethylarginines, L-arginine, haemodynamics, phosphodiesterase type 5 inhibitors, endothelin receptor antagonists
Cardiac and Cardiovascular Systems Pharmacology and Toxicology
Research subject Clinical Pharmacology
IdentifiersURN: urn:nbn:se:umu:diva-113901OAI: oai:DiVA.org:umu-113901DiVA: diva2:891007