Molecular Biological Peculiarities of the Must Cells Secretome of the Lower Limb Skin in Trophic Ulcers of Various Etiologies

The purpose of this research was to study characteristics of the mast cell (MC) secretome of the skin of the lower extremities in patients with trophic ulcers of various etiologies. Material and methods. The study included patients with venous, arterial and neurotrophic ulcers, as well as patients with the normal skin of the lower extremities. Skin specimens were stained by toluidine blue using histochemical techniques and Romanowsky–Giemsa staining; immunohistochemical protocols were used to detect MC tryptase and chymase, including the technology of multiple immune-labeling. Skin sections were studied using a ZEISS Axio Imager.A2 microscope (Carl Zeiss, Germany). Results. In the skin of patients with chronic arterial and, especially, venous insufficiency, the number of protease-containing MCs and chymase expression in the skin increased compared with the similar indicators of the skin without pathological changes. Activation of the protease secretory pathways in MCs was manifested by the release of separate tryptase and chymase-positive granules, and by the formation of granule-containing fragments of the cytoplasm. The group of patients with neurotrophic ulcers was characterized by the most expressed growth in the volume of the MC population in the skin with the increase of their size, activity of the secretory pathways and signs of polymorphism. Infiltration of the skin by MC spread into the epidermis with intensive secretion of proteases into the area of tight junctions and the intercellular matrix of the basal and spinous layers. Conclusion. MC specific proteases in chronic ulcers of the lower extremities of various etiologies may be used as an informative marker of inflammatory progression degree in the skin not only for diagnostic purposes and monitoring the effectiveness of the performed therapy but also as a promising target for pharmacological agents.