Hydrolytic enzymes of airway neutrophilic granulocytes in patients with asthma under cold stimuli exposure

Abstract

Introduction . The labilization of lysosomal membranes with the release of a wide range of lysosomal enzymes of pro-inflammatory and proapoptotic action, which have a high hydrolytic potential, is one of the essential components of adaptive changes in cells under stress. The participation of hydrolytic enzymes of phagocytes in cellular reactions of inflammation and adaptation to cold stress in patients with asthma has been little studied. Aim . To study the activity of neutrophil hydrolases of bronchi in patients with asthma under cold-induced stress. Materials and methods. In patients with persistent asthma (n=13), lung function (FEV 1 ,%), airway response (∆FEV 1 IHCA ,%) to standard 3-minute isocapnic hyperventilation with cold air (IHCA) were determined by spirometry. The collection of induced and spontaneously produced sputum after the IHCA was carried out. The activity of acidic (AP) and alkaline (ALP) phosphatases, adenosine triphosphatase (ATPase) was detected in sputum neutrophils by cytochemical methods. The assessment of the reaction to the activity of hydrolases was carried out by the semi-quantitative Kaplow method with the distribution of cells into groups depending on the color intensity of the product formed during the interaction of the enzyme with the substrate, and the subsequent calculation of the average cytochemical index (ACI) of the enzymatic activity. Results . The baseline FEV 1 , averaged 97.9±5.3%, ∆FEV 1 IHCA -2.0 (-8.0; 2.0)%. Under the influence of a cold stimulus against the background of a mixed pattern of bronchial inflammation in patients, the following was recorded: an increase in the ACI AP of neutrophils (from 1.11±0.06 to 1.42±0.06; p˂0.01), an increase in the number of cells with an average degree of AP activity (from 23.4±1.94 to 40.1±4.30%; p˂0.01) and a decrease in the number of cells with a negative reaction to AP (from 15.1±3,58 to 5.2±2.78%; p˂0.05), a tendency to an increase in the number of neutrophils with a high degree of ATPase activity (from 3.50±2.70 to 7.22±2.64%) and ALP (from 13.7±4.22 to 15.7±3.46%). Conclusion . The activation of AP of neutrophils under cold-induced stress indicates the possibility of an increase in the acidity of the interstitium, stimulation of damage and vulnerability to cold effects of the desmo-epithelial barrier of the bronchi and is regarded as a criterion for a high risk of cold airway hyperresponsiveness in asthma patients with a mixed inflammation phenotype.