Smokeless tobacco effects on monocyte secretion of PGE2 and IL-18
The aim of this study was to test the hypothesis that smokeless tobacco enhances PGE2 and IL-18 mediators either alone or in combination with LPS. Researchers isolated peripheral blood monocytes (PBM) from 15 healthy non-smokeless tobacco users. This was then incubated for 24 hours with various concentrations of smokeless tobacco (0%, 0.005%, 0.01%, 1 %) with or without 10ug/ml LPS from Porphyromonas gingivalis and Escherichia coli. The results showed that the combination of 1% ST and LPS potentiated the release of PGE2 relative to LPS alone. IL-18, on the other hand, decreased more than twofold when 1% ST and E. cold LPS were combined. IL-18 release upon combined P. gingivalis LPS and 1% ST exposure was not decreased significantly relative to P.g alone. However, two subsets emerged. P.g LPS yielded significantly greater IL-18 release in subset 2 than in subset 1. P.g LPS yielded significantly less IL-1B release than the P.g LPS + 1% ST within subset 1. The increased IL-1i3 release observed in one subset may identify a group of patients who are more susceptible to the effects of LPS and ST. The findings of this study confirm the hypothesis that ST is capable of stimulating the production of PGE2 and, depending on the LPS response, IL-12. [M.C.R.]
Payne, J., G. Johnson, R. Rienhardt, C. Maze, J. Dyer, and K. Patil, J Periodont, 65:937, 1994