Polyunsaturated Fatty Acid (PUFA) Status in Pregnant Women: Associations with Sleep Quality, Inflammation, and Length of Gestation

<div><p>Mechanistic pathways linking maternal polyunsaturated fatty acid (PUFA) status with gestational length are poorly delineated. This study examined whether inflammation and sleep quality serve as mediators, focusing on the antiinflammatory ω-3 docosahexaenoic acid (DHA; 22:6n3) and proinflammatory ω-6 arachidonic acid (AA; 20:4n6). Pregnant women (<i>n</i> = 135) provided a blood sample and completed the Pittsburgh Sleep Quality Index (PSQI) at 20–27 weeks gestation. Red blood cell (RBC) fatty acid levels were determined by gas chromatography and serum inflammatory markers [interleukin (IL)-6, IL-8, tumor necrosis factor-α, IL-1β, and C-reactive protein] by electrochemiluminescence using high sensitivity kits. Both higher serum IL-8 (95% CI = 0.10,3.84) and poor sleep (95% CI = 0.03,0.28) served as significant mediators linking lower DHA:AA ratios with shorter gestation. Further, a serial mediation model moving from the DHA:AA ratio → sleep → IL-8 → length of gestation was statistically significant (95% CI = 0.02, 0.79). These relationships remained after adjusting for depressive symptoms, age, BMI, income, race, and smoking. No interactions with race were observed in relation to length of gestation as a continuous variable. However, a significant interaction between race and the DHA:AA ratio in predicting preterm birth was observed (p = 0.049); among African Americans only, odds of preterm birth decreased as DHA:AA increased (p = 0.048). These data support a role for both inflammatory pathways and sleep quality in linking less optimal RBC PUFA status with shorter gestation in African American and European American women and suggest that African-Americans have greater risk for preterm birth in the context of a low DHA:AA ratio.</p></div

Model Linking Fatty Acid Status, Inflammation, Sleep Quality, and Length of Gestation.

<p>Represented by light boxes, we previously found that sleep quality was linked with length of gestation via serum IL-8 (Blair et al., 2015). We now demonstrate a role for fatty acid status within this model. Specifically, serial mediation models moving from RBC fatty acids → sleep → IL-8 → length of gestation demonstrated significant paths starting with DHA (95% CI = 0.001, 0.06) and the DHA:AA ratio (95% CI = 0.02, 0.79).</p

Demographic Characteristics and RBC Fatty Acid levels.

<p>Demographic Characteristics and RBC Fatty Acid levels.</p

A-C. Red blood cell fatty acid levels, serum IL-8, sleep quality and birth outcomes.

<p><b>A)</b> The DHA:AA ratio was significantly associated with serum IL-8 (r = -0.20, p = 0.02). No interactions by race were observed. <b>B)</b> Higher RBC DHA:AA ratios predicted better sleep quality, including after adjustment for depressive symptoms, age, BMI, income, race, and smoking, (b = -18.4, p < 0.001). No interactions by race were observed. <b>C)</b> A significant interaction between race and the DHA:AA ratio was observed in predicting PTB (p = 0.049). Among African Americans, odds of PTB decreased as DHA:AA increased (OR for 0.1 unit increase = 0.25 (95% CI = 0.06, 0.99), p = 0.048). This association was not present among European Americans (p = 0.99).</p

Anthropometric characteristics of study cohort at Visit 1.

<p>Data are means ± SD. <i>p</i>-value:comparison between visits within each group. Maternal blood was obtained following fasting. GA-Gestational age; AA-African American; Cauc-Caucasian; other-Hispanic, Asian.</p><p>Anthropometric characteristics of study cohort at Visit 1.</p

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

<p><b>A-B. Stimulation of TLR4 mRNA.</b> 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. <b>C-D. Stimulation of IL6, IL8 mRNA.</b> 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.</p

Effect of maternal omega 3 supplementation on inflammatory markers.

<p><b>A. Placenta.</b> Quantitative RT-PCR analysis of total RNA isolated from placenta tissue. <b>B. Maternal white adipose tissue.</b> 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.</p

Maternal fatty acid profile at visit 1 and visit 2.

<p>Data are means ± SD. <i>p</i>-value:comparison between placebo and ω-3 treated groups at visit 1 and 2.</p><p>ɸ <i>p</i> < 0.005</p><p>NS-not significant.</p><p>Maternal fatty acid profile at visit 1 and visit 2.</p