Fish oils (FOs) have anti-inflammatory effects and lower serum triglycerides. This study examined adipose and muscle inflammatory markers after treatment of humans with FOs and measured the effects of ω-3 fatty acids on adipocytes and macrophages in vitro. Insulin-resistant, nondiabetic subjects were treated with Omega-3-Acid Ethyl Esters (4 g/day) or placebo for 12 weeks. Plasma macrophage chemoattractant protein 1 (MCP-1) levels were reduced by FO, but the levels of other cytokines were unchanged. The adipose (but not muscle) of FO-treated subjects demonstrated a decrease in macrophages, a decrease in MCP-1, and an increase in capillaries, and subjects with the most macrophages demonstrated the greatest response to treatment. Adipose and muscle ω-3 fatty acid content increased after treatment; however, there was no change in insulin sensitivity or adiponectin. In vitro, M1-polarized macrophages expressed high levels of MCP-1. The addition of ω-3 fatty acids reduced MCP-1 expression with no effect on TNF-α. In addition, ω-3 fatty acids suppressed the upregulation of adipocyte MCP-1 that occurred when adipocytes were cocultured with macrophages. Thus, FO reduced adipose macrophages, increased capillaries, and reduced MCP-1 expression in insulin-resistant humans and in macrophages and adipocytes in vitro; however, there was no measureable effect on insulin sensitivity. Diabetes 62:1709–1717, 2013
Digital Object Identifier (DOI)
Spencer, Michael; Finlin, Brian S.; Unal, Resat; Zhu, Beibei; Morris, Andrew J.; Shipp, Lindsey R.; Lee, Jonah D.; Walton, R. Grace; Adu, Akosua; Erfani, Rod; Campbell, Marilyn S.; McGehee, Robert E. Jr.; Peterson, Charlotte A.; and Kern, Philip A., "Omega-3 Fatty Acids Reduce Adipose Tissue Macrophages in Human Subjects with Insulin Resistance" (2013). Clinical and Translational Science Faculty Publications. 25.