Relationship between nitric oxide levels and the activity of fibrogenic cytokine TGF-β1 and their role in diagnostics of the development of irreversible morphofunctional changes in bronchi of smoking adolescents

The aim is to study the relationship between the level of exhaled nitric oxide (FeNO) and the activity of the fibrogenic cytokine TGF-β1 in blood serum and brush biopsy samples of bronchial mucosa in order to determine their role in the development of irreversible morphological and functional changes in smoking adolescents. Materials and methods. 20 adolescent smokers with chronic bronchitis (CB) (average age – 17.5 ± 0.2 years) were exa­mined. The comparison group consisted of 37 adolescent smokers without respiratory symptoms (average age – 15.9 ± 0.2 years) and 15 healthy adolescents, who never smoked (average age – 15.9 ± 0.4 years). In adolescent smokers the tobacco smoking status was assessed. To confirm active smoking, the nicotine metabolite cotinine was determined in urine. Instrumental methods included spirometry, chest X-ray, tracheobronchoscopy. The FeNO level was measured using a Niox Mino. TGF-β1 level was determined in the blood serum and brush biopsy samples of the bronchial mucosa. Results. The FeNO levels were significantly lower in adolescent smokers with CB in comparison with adolescent smokers without respiratory symptoms (6.1 ± 0.3 ppb versus 8.8 ± 0.6 ppb, P