Also, the protein levels of COX‐1, cPGES, and FLAP, which are key enzymes in the biosynthesis of pro‐inflammatory PG and LT (Radmark et al., 2015; Smith et al., 2011), were decreased in old PM, along with considerably lower PGE2 and LTB4 formation upon infection with pathogenic E. coli. This evidence concerns the gene LTA and infection.