Abstract
The interaction between lymphocytes, cytokines, and endothelial cells (EC) is a key step in the inflammatory process. Interleukin-6 (IL-6), a pleiotropic cytokine in its effects, seems to be an early indicator of acute systemic inflammation. We examined the effects of polyunsaturated fatty acids (PUFA) on the production of IL-6 by human unstirnulated EC and by EC stimulated with TNF-α (100U/ml), IL-4 (100U/ml), LPS (1 μg/ml), or allogeneic peripheral blood lymphocytes (PBL). Immunoreactive IL-6 of twenty-four hour culture Supernatants was measured by sandwich ELISA. We demonstrated that the production of IL-6 was potentiated when EC were stimulated with TNF-α, IL-4, LPS, or monocyte-depleted PBL in comparison to unstimulated EC. The addition of n-3 PUFA to the culture medium (100 pglml DHA or EPA) significantly reduced the production of IL-6 by unstimulated EC and by EC stimulated with TNF-α, IL4, LPS or depleted PBL, whereas the n-6 PUFA (Arachidonic acid), even used at a similar concentration, was ineffective. This inhibitory effect was PUFA dose-dependent. Regardless of the mode of action, these results suggest that n-3 PUFA have a role in suppressing inflammation. Further studies are needed to elucidate the mechanism involved and the choice between the two fatty acids for clinical and therapeutic purposes.