Dose-dependent effect of bacterial polyamines on the viability of human peripheral blood leukocytes

Morozov I.A., Godovalov A.P., Karpunina T.I.

Acad. E.A. Wagner Perm State Medical University, Perm

Recently, much attention has been paid to the role of microbial communities in the development of human pathological conditions. However, as a rule, such researches concern only the taxonomic characteristics of the microbiota. In turn, relatively little attention is paid to bacterial metabolites, which, in addition to intermicrobial communications, are involved in interaction with eukaryotic cells. The aim of investigation was to study the effect of cadaverine and putrescine on the viability of human peripheral blood leukocytes. We used peripheral blood samples from 15 healthy volunteers, from which mononuclear leukocytes were obtained by gradient centrifugation. The cell suspension was incubated at 37 °C under 5 % CO2 for 72 h with polyamines at concentrations of 5, 25, 50, 75, and 100 mmol/l. At the end of the incubation in the wells, the total number of cells was counted, including the number of viable cells in the test with 0.1 % trypan blue solution. During investigation, it was shown that an increase in the concentration of putrescine correlates with a decrease in the total number of cells (r = –0.75). In samples with cadaverine concentrations of 5 and 25 mmol/l, the total number of cells increased to 3014 ± 1312 and 4000 ± 1292 in 1 µl, respectively, against 1990 ± 1036 in 1 µl in control samples (p < 0.05). However, in samples with a high content of cadaverine, an increase in the total number of leukocytes was not registered. In general, polyamines of bacterial origin have a multidirectional effect on the viability of mononuclear leukocytes. The action of putrescine is probably due to the large accumulation of toxic products during its metabolism by leukocytes. In turn, low concentrations of cadaverine can be involved in the regulation of the cell life cycle.