Omega-3 PUFA supplementation and the response to evoked endotoxemia in healthy volunteers

Abstract

Scope: Fish oil-derived n-3 PUFA may improve cardiometabolic health through modulation of innate immunity. However, findings in clinical studies are conflicting. We hypothesized that n-3 PUFA supplementation would dose-dependently reduce the systemic inflammatory response to experimental endotoxemia in healthy humans.

Methods and results: The Fenofibrate and omega-3 Fatty Acid Modulation of Endotoxemia (FFAME) study was an 8-wk randomized double-blind trial of placebo or n-3 PUFA supplementation (Lovaza 465 mg eicosapentaenoic acid (EPA) + 375 mg docosahexaenoic acid (DHA)) at "low" (1/day, 900 mg) or "high" (4/day, 3600 mg) dose in healthy individuals (N = 60; age 18-45; BMI 18-30; 43% female; 65% European-, 20% African-, 15% Asian-ancestry) before a low-dose endotoxin challenge (LPS 0.6 ng/kg intravenous bolus). The endotoxemia-induced temperature increase was significantly reduced with high-dose (p = 0.03) but not low-dose EPA + DHA compared to placebo. Although there was no statistically significant impact of EPA + DHA on individual inflammatory responses (tumor necrosis factor-α (TNF-α), IL-6, monocyte chemotactic protein (MCP-1), IL-1 receptor agonist (IL-1RA), IL-10, C-reactive protein (CRP), serum amyloid A (SAA)), there was a pattern of lower responses across all biomarkers with high-dose (nine of nine observed), but not low-dose EPA + DHA.

Conclusion: EPA + DHA at 3600 mg/day, but not 900 mg/day, reduced fever and had a pattern of attenuated LPS induction of plasma inflammatory markers during endotoxemia. Clinically and nutritionally relevant long-chain n-3 PUFA regimens may have specific, dose-dependent, anti-inflammatory actions.

Keywords: Endotoxemia; Fish oil; Inflammation; LPS; n-3 PUFA.

Figure 1. Design of the FFAME Study

After screening, subjects were randomized to EPA+DHA or placebo for 6–8 weeks, followed by a lipopolysaccharide (LPS) challenge inpatient visit.

Figure 2. Flow diagram for the FFAME study

100 subjects were randomized, to allow for an expected 20% rate of dropout, and achieve our goal of 80 completers. A separate fenofibrate arm of the study has been analyzed and reported independently.

Figure 3. Change in red blood cell membrane fatty acids following EPA+DHA treatment; (A) Eicosapentaenoic acid (EPA), (B) Docosahexaenoic acid (DHA) and (C) combined EPA and DHA

The proportion of EPA and DHA in the red blood cell membrane increased significantly following EPA+DHA supplementation. Arachidonic acid (AA), EPA and DHA expressed as percentage of total fatty acids measured (AA+EPA+DHA).

Figure 4. Temperature response to LPS in EPA+DHA treated groups compared to placebo

Subjects treated with high-dose EPA+DHA (Lovaza 4/day) had a significantly reduced temperature response compared with placebo (AUC P=0.046). This reduction was not observed in the low-dose EPA+DHA group

Figure 5. Inflammatory responses to LPS in high-dose and low-dose EPA+DHA treated subjects compared to placebo

(A) Tumor necrosis factor-α (TNFα); (B) Interleukin-6 (IL-6); (C) Interleukin-10 (IL-10); (D) Interleukin-1 receptor agonist (IL-1RA); (E) Monocyte chemotactic protein-1 (MCP-1); (F) C-reactive Protein (CRP); (G) Serum amyloid A (SAA). ⊟ Placebo Lovaza (1/day) ⊗ Lovaza (4/day)

Figure 5. Inflammatory responses to LPS in high-dose and low-dose EPA+DHA treated subjects compared to placebo

(A) Tumor necrosis factor-α (TNFα); (B) Interleukin-6 (IL-6); (C) Interleukin-10 (IL-10); (D) Interleukin-1 receptor agonist (IL-1RA); (E) Monocyte chemotactic protein-1 (MCP-1); (F) C-reactive Protein (CRP); (G) Serum amyloid A (SAA). ⊟ Placebo Lovaza (1/day) ⊗ Lovaza (4/day)

Figure 5. Inflammatory responses to LPS in high-dose and low-dose EPA+DHA treated subjects compared to placebo

(A) Tumor necrosis factor-α (TNFα); (B) Interleukin-6 (IL-6); (C) Interleukin-10 (IL-10); (D) Interleukin-1 receptor agonist (IL-1RA); (E) Monocyte chemotactic protein-1 (MCP-1); (F) C-reactive Protein (CRP); (G) Serum amyloid A (SAA). ⊟ Placebo Lovaza (1/day) ⊗ Lovaza (4/day)

Figure 5. Inflammatory responses to LPS in high-dose and low-dose EPA+DHA treated subjects compared to placebo

(A) Tumor necrosis factor-α (TNFα); (B) Interleukin-6 (IL-6); (C) Interleukin-10 (IL-10); (D) Interleukin-1 receptor agonist (IL-1RA); (E) Monocyte chemotactic protein-1 (MCP-1); (F) C-reactive Protein (CRP); (G) Serum amyloid A (SAA). ⊟ Placebo Lovaza (1/day) ⊗ Lovaza (4/day)

Figure 5. Inflammatory responses to LPS in high-dose and low-dose EPA+DHA treated subjects compared to placebo

(A) Tumor necrosis factor-α (TNFα); (B) Interleukin-6 (IL-6); (C) Interleukin-10 (IL-10); (D) Interleukin-1 receptor agonist (IL-1RA); (E) Monocyte chemotactic protein-1 (MCP-1); (F) C-reactive Protein (CRP); (G) Serum amyloid A (SAA). ⊟ Placebo Lovaza (1/day) ⊗ Lovaza (4/day)

Figure 5. Inflammatory responses to LPS in high-dose and low-dose EPA+DHA treated subjects compared to placebo

(A) Tumor necrosis factor-α (TNFα); (B) Interleukin-6 (IL-6); (C) Interleukin-10 (IL-10); (D) Interleukin-1 receptor agonist (IL-1RA); (E) Monocyte chemotactic protein-1 (MCP-1); (F) C-reactive Protein (CRP); (G) Serum amyloid A (SAA). ⊟ Placebo Lovaza (1/day) ⊗ Lovaza (4/day)

Figure 5. Inflammatory responses to LPS in high-dose and low-dose EPA+DHA treated subjects compared to placebo

(A) Tumor necrosis factor-α (TNFα); (B) Interleukin-6 (IL-6); (C) Interleukin-10 (IL-10); (D) Interleukin-1 receptor agonist (IL-1RA); (E) Monocyte chemotactic protein-1 (MCP-1); (F) C-reactive Protein (CRP); (G) Serum amyloid A (SAA). ⊟ Placebo Lovaza (1/day) ⊗ Lovaza (4/day)