Effect of docosahexaenoic acid as an anti-inflammatory for Caco-2 cells and modulating agent for gut microbiota in children with obesity (the DAMOCLE study).

Abstract

Docosahexaenoic acid (DHA) is a long-chain omega-3 polyunsaturated fatty acid. We investigated the dual health ability of DHA to modulate gut microbiota in children with obesity and to exert anti-inflammatory activity on human intestinal Caco-2 cells. In a pilot study involving 18 obese children (8-14years), participants received a daily DHA supplement (500mg/day) and dietary intervention from baseline (T0) to 4months (T1), followed by dietary intervention alone from 4months (T1) to 8months (T2). Fecal samples, anthropometry, biochemicals and dietary assessment were collected at each timepoint. At preclinical level, we evaluated DHA's antioxidant and anti-inflammatory effects on Caco-2 cells stimulated with Hydrogen peroxide (H2O2) and Lipopolysaccharides (LPS), by measuring also Inducible nitric oxide synthase(iNOS) levels and cytokines, respectively. Ten children were included in final analysis. No major changes were observed for anthropometric and biochemical parameters, and participants showed a low dietary compliance at T1 and T2. DHA supplementation restored the Firmicutes/Bacteroidetes ratio that was conserved also after the DHA discontinuation at T2. DHA supplementation drove a depletion in Ruminococcaceae and Dialisteraceae, and enrichment in Bacteroidaceae, Oscillospiraceae, and Akkermansiaceae. At genus level, Allisonella was the most decreased by DHA supplementation. In Caco-2 cells, DHA decreased H2O2-induced reactive oxygen species (ROS) and nitric oxide (NO) production via iNOS pathway modulation. Additionally, DHA modulated proinflammatory (IL-1β, IL-6, IFN-γ, TNF-α) and anti-inflammatory (IL-10) cytokine production in LPS-stimulated Caco-2 cells. An improvement in gut dysbiosis of children with obesity seems to be triggered by DHA and to continue after discontinuation. The ability to modulate gut microbiota, matches also with an anti-inflammatory effect of DHA on Caco-2 cells.