[Expression of serotonin and vessel endothelial growth factor (VEGF) in human thymus in aging involution]

Immunohistochemical verification of serotonin and of the vessels endothelial growth factor (VEGF) has enabled to establish the presence of these signaling molecules in human thymus in all stages of ontogenesis and in aging. Thus authentic increase of quantity of the cells synthesizing serotonin in people of advanced age is established, which reflects the compensatory role of serotonin, directed on maintenance of immunity in old organism. The minimum quantity of the cells containing VEGF is observed in human thymus of advanced age, but the intensity of synthesis of this peptide does not practically change during the postnatal ontogenesis. These data may be considered as the evidence of the important role of signaling molecules that are expressed in thymus in local paracrine regulation of thymic functions in aging.