Pro-inflammatory monocytes are increased in Duchenne muscular dystrophy and suppressed with omega-3 fatty acids: A double-blind, randomized, placebo-controlled pilot study

Background: Omega-3 long chain polyunsaturated fatty acids (LCPUFA) reduce circulating cytokines produced by monocytes. Nevertheless, whether the omega-3 LCPUFA regulate the monocytes and their cytokines in Duchenne muscular dystrophy (DMD) is unknown. The aim of this study was to evaluate whether circulating pro-inflammatory monocytes are increased and whether omega-3 LCPUFA selectively suppress these monocytes and their cytokines in patients with DMD. Methods: This was a double-blind, randomized, placebo-controlled pilot study carried out in patients with DMD supplemented with omega-3 LCPUFA (n = 6) or sunflower oils (placebo, n = 6) for 6 months. Monocytes and their cytokines were measured at baseline and after 1, 2, 3, and 6 months of supplementation. Results: The anti-inflammatory monocytes (median, [95% CI]) are increased at month 3 (−0.46 [−13.5–9.5] vs. 8.4 [5.5–12.5], p = 0.05) in the omega-3 LCPUFA group compared with the placebo group. The pro-inflammatory monocytes (−5.7 [−63.8–114.1] vs. −51.9 [−91.2 to −25.4], p = 0.026 and −16.4 [−50.8–50.6] vs. −57.9 [−86.9 to −18.5], p = 0.045 at months 3 and 6, respectively) and their cytokine interleukin 6 (−11.9 [−93.5–148.9] vs. −64.7 [−77.8 to −42.6], p = 0.019 at month 6) decreased in the omega-3 LCPUFA group compared with the placebo group. Pro-inflammatory monocytes decreased and anti-inflammatory monocytes were augmented (p < 0.05) during the 6 months of supplementation with omega-3 LCPUFA. Conclusions: This pilot study suggests that supplementation with omega-3 LCPUFA could have a selective reductive effect on pro-inflammatory monocytes and their cytokines in patients with DMD. These findings also support the performance of studies in a significant population to explore the role of omega-3 LCPUFA on monocyte populations and their cytokines in patients with DMD. This research was registered at clinicaltrials.gov (NCT018264229).