Effect of PEA on LPS inflammatory action in human adipocytes.
N-Palmitoylethanolamide (PEA) is an endogenous lipid secreted by human adipocytes that possesses numerous anti-inflammatory properties. Human adipose tissue can be subjected to modulation of its inflammatory state by lipopolysaccharide (LPS). Here we demonstrate that LPS increases the secretion of interleukin-6 (IL-6) by human mature adipocytes via activation of the NFkappaB pathway. This effect is not inhibited by PEA. Inversely, LPS strongly inhibits adipose cell leptin release, with PEA acting as a potentiator of this inhibitory effect. These actions are not linked to a reduction in leptin gene transcription. Thus, PEA does not have an anti-inflammatory role in the secretion of IL-6 via NFkappaB at the adipocyte level, but instead seems to act at the heart of the LPS-stimulated pathway, which, independently of NFkappaB, inhibits the secretion of leptin.