Dietary Omega-3 Fatty Acid Supplementation Reduces Inflammation in Obese Pregnant Women: A Randomized Double-Blind Controlled Clinical Trial

Abstract

Objective: Long-chain omega 3 fatty acids, eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) exert potent anti-inflammatory properties in humans. This study characterized the effects of omega-3 ω-3 fatty acids supplements (ω-3 FA) on the inflammatory status in the placenta and adipose tissue of overweight/obese pregnant women.

Study design: A randomized, double-masked controlled trial was conducted in overweight/obese pregnant women that were randomly assigned to receive DHA plus EPA (2 g/day) or the equivalent of a placebo twice a day from week 10-16 to term. Inflammatory pathways were characterized in: 1) adipose tissue and placenta of treated vs. untreated women; and 2) adipose and trophoblast cells cultured with long chain FAs.

Results: The sum of plasma DHA and EPA increased by 5.8 fold and ω-3 FA/ω-6 FA ratio was 1.5 in treated vs. untreated women (p< 0.005). Plasma CRP concentrations were reduced (p<0.001). The adipose tissue and placenta of treated women exhibited a significant decrease in TLR4 adipose and placental expression as well as IL6, IL8, and TNFα In vitro, EPA and DHA suppressed the activation of TLR4, IL6, IL8 induced by palmitate in culture of adipose and trophoblast cells.

Conclusion: Supplementation of overweight/obese pregnant women with dietary ω-3 FAs for >25 weeks reduced inflammation in maternal adipose and the placental tissue. TLR4 appears as a central target of the anti-inflammatory effects at the cellular level.

Trial registration: ClinicalTrials.gov NCT00957476.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1. Study Design–Schematic diagram showing how subjects were progressed through the study and how the final study samples were obtained.

Fig 2. Effect of maternal omega 3 supplementation on inflammatory markers.

A. Placenta. Quantitative RT-PCR analysis of total RNA isolated from placenta tissue. B. Maternal white adipose tissue. Quantitative RT-PCR analysis of total RNA isolated from adipose tissue. Data (mean ± SEM) were expressed as copies per ng RNA in placebo vs. ω3-PUFA treated after normalization to β-actin. Total RNA was isolated from placenta and adipose tissue collected at the time of cesarean section from the recruited women. IL8, IL6, TNFα and TLR4 mRNA levels were measured by quantitative RT-PCR analysis. IL, interleukin; TNFα, tumor necrosis factor alpha; TLR4, toll-like receptor 4; RT-PCR, reverse transcriptase-PCR.

Fig 3. In vitro effects of dietary fatty acids on TLR4 signaling pathways in placental and adipose cells.

A-B. Stimulation of TLR4 mRNA. Quantitative RT-PCR analysis of TLR 4 from total RNA isolated from cultured trophoblast cells (A) or stromal adipose cells (B)from 4–10 obese women. C-D. Stimulation of IL6, IL8 mRNA. Quantitative RT-PCR analysis of IL6 and IL8 from total RNA isolated from cultured trophoblast cells (C) or stromal adipose cells (D)from 4–14 obese women. Cells were stimulated for 24h with 100 ng/ml LPS, PA 500 μM, OA 500 μM, EPA 50 μM and DHA 50 μM. LPS, lipopolysaccharide; PA, palmitic acid; IL, interleukin; TLR4, toll-like receptor 4; OA, oleate; RT-PCR, reverse transcriptase-PCR. Data (mean ± SEM) were expressed as fold changes in FA/ω3-PUFA-treated vs. untreated after normalization to β-actin. Statistical significance: * p< 0.05 vs. control; ¥ p< 0.05 vs. PA-stimulation of IL6; § p< 0.05 vs. PA-stimulation of IL8.