EFFECT OF EOSINOPHILS ADHESION TO AIRWAY SMOOTH MUSCLE CELLS PROLIFERATION IN ASTHMA

Abstract

Introduction. Eosinophilic airway inflammation is an important feature in asthma pathogenesis. Eosinophils are adhesive cells, because they have themain adhesion receptors – integrins, that are responsible not only for eosinophils attachment, but also can act as signal-transdusers between communicating cells. It is believed that not all eosinophils are characterized by the same adhesive properties and depending on it can have a different functions. Based on it, better understanding of eosinophils adhesion could be adapted on integrins or their ligands blocking with specific antibodies, reducing eosinophils effect to airway structural changes in asthma. Aim – to evaluate the importance of eosinophils adhesion to airway smooth muscle (ASM) cells proliferation in asthma. Methods. 7 steroids-free asthmatic patients and 6 non-smoking healthy subjects were included into the study. Peripheral blood eosinophils were isolated by using high density Ficoll centrifugation and magnetic seperation. An
individual combined cell cultured between immortalised airway smoothmuscle (ASM) cells and isolated eosinophils wasmade, by using different ratio (37,500 and 6,250, 12,500 and 25,000 eosinophils respectively). Eosinophils adhesion was evaluated by
measuring eosinophils peroxidase activity in combined cell cultures. ASM cells proliferation after 72 h of making combined cell cultures by Alamar blue assay. Results. By using the ratio of ASM cells and asthmatic eosinophils 1:6 and 1:3 was received
similar attached eosinophils proportion – respectively 63.0±6.2% and 70.9±4.6% from whole added eosinophils. Increasing added asthmatic eosinophils count to the ratio 1:1.5 was received significantly reduced proportion of attached eosinophils to
48.9±5.1 (p<0.05), probably due to not enough specific adhesive sites. Meanwhile measuring healthy eosinophils adhesion in all cases resultsmaintain similar, respectively 45.0±4.1, 48.7±5.7 and 49.5±3.4. Similar tendency noticedmeasuring eosinophils effect to ASM proliferation. Although in asthmatic patients group after using ratios 1:6 and 1:3 absolute number of attached eosinophils was different, their effect to ASM cells remains the same (respectively increase in 13.0±4.1 and 14.4±2.2%, p<0.05) comparing with proliferation of control ASM cells, without incubation with eosinophils. Whereas after increasing added asthmatic eosinophils count to the ratio 1:1.5 statistically significant effect to cells proliferation was not received. In healthy
eosinophils group after using ratios 1:6 and 1:3 significant effect to ASM cells proliferation was not determined, however, after increasing added asthmatic eosinophils count to the ratio 1:1.5 was received significantly reduced ASM cells proliferation by 8.5±3.4% (p<0.05). Conclusion. Adhesive eosinophils ratio in peripheral blood remains stable and eosinophils activity and effect to ASM cells proliferation depends by eosinophils adhesive properties.