Extracts of smokeless tobacco induce pro-inflammatory changes in cultured human vascular endothelial cells

Habitual use of smokeless tobacco leads to accumulation of inflammatory leukocytes at the site of placement, which may contribute to tissue damage. Recruitment of leukocytes is facilitated by the endothelial lining of blood vessels, which can be activated to express adhesion molecules and to produce chemoattractants. The ability of aqueous extracts of chewing tobacco, dry snuff, and moist snuff to stimulate such changes was investigated using cultured human umbilical vein endothelial cells (HUVEC). All three extracts caused HUVEC to express the adhesion molecule E-selectin and to produce the chemokines interleukin-8 and monocyte chemoattractant protein-1. Neutrophils migrated avidly across HUVEC monolayers that had been previously exposed to the extracts, whereas migration across unstimulated monolayers was negligible. The smokeless tobacco extracts contained relatively high concentrations of bacterial lipopolysaccharide (LPS). Although LPS appeared to be the major stimulatory component in extracts of chewing tobacco, it accounted for only part of the activity found in extracts of moist and dry snuffs. These observations suggest that smokeless tobacco may induce inflammatory changes in vivo by activating endothelium in a manner that promotes recruitment of leukocytes.