Nitrogen Oxide Content in the Expired Air of Patients with Asthma and Chronic Obstructive Pulmonary Disease, as Related to Disease Progression

Nitrogen oxide (NO) is well known as an atmospheric pollutant, which is contained in automobile exhaust fumes and cigarette smoke. Over the past 20 years, since the numerous biological functions of NO have become known, this gas has been studied in healthy individuals and in the presence of pathology. Nitrogen oxide was discovered during an experiment to activate gyanylate cyclase to form cyclic guanosine monophosphate in 1977 [1]. The year 1980 can be considered as the beginning of NO studies for clinical purposes, when it was discovered that some vasodilators do not have an effect when the vascular epithelium is damaged [2]. It was found that nitrogen oxide is the factor synthesised by the coronary artery epithelium, which causes vessel dilation [3]. The first publication about NO content in human and animal expired air was published in 1991 [4]. In 1993, the Journal Science called NO “molecule of the year”. It was later discovered that NO is formed not only in the endothelium, but also in other cells, such as the epithelium, neurons, monocytes and lymphocytes [5]. It was determined that NO is one of the most important mediators in the cardiovascular, respiratory, nervous, immune, gastrointestinal and genitourinary systems [6].