Dietary eicosapentaenoic and docosahexaenoic acids reduce oxylipins that provide early mediators of colonic inflammation induced by chemotherapy

Abstract

Combination chemotherapy, irinotecan+5-fluorouracil, treats advanced colorectal cancer but causes intestinal toxicity mediated by cytokines and oxylipins. The objective of this study is to determine the effect of dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cytokines and the balance of oxylipins in colon tissue after chemotherapy. Ward colon tumors were implanted into female Fischer 344 rats (13–14 weeks old, n=56) and grew for 2 weeks before initiating chemotherapy (day 0). Subsequently, rats were maintained on the control diet (n=32) or switched to the EPA+DHA diet (n=24), an isocaloric diet that differed mainly in EPA and DHA content. Rats were euthanized on day 0 (baseline), 2, 4 and 8. The reference (no tumor, n=8) and baseline D0 (with tumor, n=8) groups did not receive chemotherapy. Cytokines, phospholipid fatty acids, and oxylipins in colon tissue were compared between the diets and over days post-chemotherapy. Feeding EPA+DHA resulted in a 9- and 2-fold increase in colon phospholipid by day 8 mirrored by a 10- and 2-fold increase in total oxylipins derived from EPA and DHA, respectively. Incorporation of EPA and DHA by day 2 prevented an increase in pro-inflammatory arachidonic acid (AA)-derived oxylipins after chemotherapy, including prostaglandin (PG) D₂, PGE₂, 6-keto-PGF_1α, thromboxane B₂, and 5-hydroxyeicosatetraenoic acid. Displacement of AA by EPA and DHA in colonic membrane attenuates early inflammatory lipid oxylipins. Dietary EPA+DHA may mitigate intestinal perturbations in colorectal cancer patients receiving irinotecan+5-fluorouracil.