APELIN-12 AND APELIN-36 IN SPUTUM OF PATIENTS WITH BRONCHIAL ASTHMA

Relevance. In recent years, adipokines are considered as participants of pathogenesis in bronchial asthma (BA). The vast majority of studies on adipokines is based on the study of plasma (systemic) levels of adipokines. Studies of the influence of adipokines at the local, organ (lung) level are sporadic but extremely important. However, the available literature contains no research on the content of apelin – this newly discovered adipokine – in sputum.

The aim is to detect the presence of two isoforms of apelin: apelin-12 and apelin-36 in BA in the target organ (in sputum) and to establish their possible participation in the pathogenesis of the disease.

Materials and methods. 13 patients with bronchial asthma (BA) with different variants of the disease were examined. Sputum was obtained naturally (without induction). The sputum levels of apelin-12 and apelin-36 were determined by an enzyme immunoassay kit of «Human Apelin 36 ELISA Kit» (Cusabio, China), «Human Apelin 12 ELISA Kit» (Cusabio, China).

Results. In the sputum of patients with BA, both investigated apelins were identified: apelin-12 and apelin-36, but there were no significant differences between the levels of these apelins in allergic BA and non-allergic BA. Strong negative correlations of the apelin-12 level in sputum with volumetric values of external respiratory function (ERF) were revealed, as well as positive correlations between the apelin-12 level and the color index, mean erythrocyte volume. These two groups of correlations point to possible involvement of apelin-12 in the regulation of gas exchange, transfer of oxygen by erythrocytes, formation of a hypoxic state. Correlations of different directionality of apelin-36 in sputum with indicators of external respiration function in allergic BA and non-allergic BA have been revealed. In BA, there are inverse correlations between the levels of the apelins: apelin-12 with a relative amount of sputum eosinophils, and apelin-36 with a relative amount of sputum neutrophils.

Conclusions. The assumption is made on the predominantly paracrine function of the apelins (not associated with the endocrine function) in BA. It is assumed that the isoforms of the apelins, having opposite in their directional correlations in different variants of BA, may apparently participate as a protective regulator in respect of a number of processes underlying allergic and non-allergic inflammation.

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