Title:The Nitric Oxide Pathway in Pulmonary Arterial Hypertension: Pathomechanism, Biomarkers and Drug Targets
Volume: 27
Issue: 42
Author(s): Zsófia Lázár, Martina Mészáros and Andras Bikov*
Affiliation:
- Department of Pulmonology, Semmelweis University, Budapest,Hungary
Keywords:
Pulmonary arterial hypertension, nitric oxide, nitric oxide synthase, FENO, biomarkers, systemic
sclerosis.
Abstract: The altered Nitric Oxide (NO) pathway in the pulmonary endothelium leads to increased
vascular smooth muscle tone and vascular remodelling, and thus contributes to the
development and progression of pulmonary arterial hypertension (PAH). The pulmonary NO
signalling is abrogated by the decreased expression and dysfunction of the endothelial NO
synthase (eNOS) and the accumulation of factors blocking eNOS functionality. The NO deficiency
of the pulmonary vasculature can be assessed by detecting nitric oxide in the exhaled
breath or measuring the degradation products of NO (nitrite, nitrate, S-nitrosothiol) in blood
or urine. These non-invasive biomarkers might show the potential to correlate with changes in
pulmonary haemodynamics and predict response to therapies. Current pharmacological therapies
aim to stimulate pulmonary NO signalling by suppressing the degradation of NO (phosphodiesterase-
5 inhibitors) or increasing the formation of the endothelial cyclic guanosine
monophosphate, which mediates the downstream effects of the pathway (soluble guanylate
cyclase sensitizers). Recent data support that nitrite compounds and dietary supplements rich
in nitrate might increase pulmonary NO availability and lessen vascular resistance. This review
summarizes current knowledge on the involvement of the NO pathway in the pathomechanism
of PAH, explores novel and easy-to-detect biomarkers of the pulmonary NO.