HUMAN NEUTROPHIL CHEMOKINESIS AND POLARIZATION-INDUCED BY HYALURONIC-ACID DERIVATIVES

Neutrophils and macrophages are known to undergo significant modificat ions in their morphology and basal metabolism in response to chemical factors, in particular changes in the shape, movement, phagocytic acti vity and degranulation. These phenomena often involve an increase in c hemokinesis and cellular secretory activity, usually expressed in anti microbial activity. Once activated, the cells can move quickly towards the source of the stimulus, where they produce and release great amou nts of enzymes (e.g. proteases, hydrolases, lysozyme) and reactive oxy gen metabolites (e.g. O2-., H2O2, OH.). This study has examined the ab ility of surfaces of selected biomaterials to influence neutrophil mor phology and locomotion. The surface of two films derived from hyaluron ic acid derivatives were compared with that of glass. The two hyaluron ic acid derivatives, despite having a similar chemical structure, were shown to interact with human neutrophils in different ways. A hyaluro nic acid ethyl ester stimulated the whole population of neutrophils to take up a non-spherical morphology (polarize) and to move with a velo city similar to that of formyl-methionine-leucine-phenylalanine-stimul ated cells on a glass surface. In contrast, only 44% of the examined c ells on the surface of hyaluronic acid benzyl ester were polarized and their mean speed was only slightly higher with respect to that found with non-stimulated cells on glass. Moreover, while on the benzyl este r and on glass a correlation between neutrophil circularity (i.e. the shape of the cell) and cell speed was found, the ethyl ester did not s how any correlation.