Oxylipins are specialized lipid mediators that can have dual functions,
either promoting inflammation or supporting resolution. Exposure to air
pollution is associated with systemic inflammation that may be modified
by oxylipins derived from polyunsaturated fatty acids (FA). In this
study, we examined whether short-term air pollution exposure is
associated with changes in circulating oxylipins in healthy adults, who
were on high- or low-dietary omega-3 fatty acid (n-3 FA) intakes. We
measured 56 oxylipin species from participants’ plasma samples and
employed mixed-effects models to assess the associations, stratified by
n-3 FA groups. Plasma concentrations of oxylipins derived from n-3 FA
[e.g., 14-hydroxydocosahexaenoic acid (14-HDHA) &
11-hydroxydocosahexaenoic acid (11-HDoHE), and
12-hydroxyeicosapentaenoic acid (12-HEPE)] were significantly higher in
the high n-3 FA group compared to the low group. Conversely, selected
oxylipins derived from n-6 FA [e.g., 15-hydroxyeicosatetraenoic acid
(15-HETE) and 14,15-Dihydroxyeicosatrienoic acid (14,15-DiHETrE)] were
significantly lower in the high n-3 group. Exposure to PM2.5, O3, and NO2
was associated with reductions in pro-inflammatory oxylipins produced
by lipoxygenase in the high n-3 FA group, but not in the low group; for
example, 12-HETE. Furthermore, participants in the high n-3 group
exposed to PM2.5, O3, and NO2 had
elevated levels of n-3 FA-derived pro-resolving oxylipins compared to
those in the low n-3 group; for instance, 12-HEPE and 14-HDHA &
11-HDoHE. In conclusion, short-term air pollution exposure was
associated with lower pro-inflammatory and higher pro-resolving oxylipin
levels in the high n-3 FA group. These findings suggest n-3-derived
lipid metabolites may promote inflammation resolution induced by air
pollution.