Omega-3 Fatty Acids Reduce Adipose Tissue Macrophages in Human Subjects With Insulin Resistance
- Michael Spencer1,
- Brian S. Finlin1,
- Resat Unal1,
- Beibei Zhu1,
- Andrew J. Morris2,
- Lindsey R. Shipp1,
- Jonah Lee3,
- R. Grace Walton1,
- Akosua Adu1,
- Rod Erfani3,
- Marilyn Campbell3,
- Robert E. McGehee Jr.4,
- Charlotte A. Peterson3 and
- Philip A. Kern1⇑
- 1Department of Medicine, Division of Endocrinology, and the Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, Kentucky
- 2Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky
- 3College of Health Sciences, University of Kentucky, Lexington, Kentucky
- 4Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Corresponding author: Philip A. Kern, .
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.
This article contains Supplementary Data online at http://diabetes.diabetesjournals.org/lookup/suppl/doi:10.2337/db12-1042/-/DC1.
- Received August 2, 2012.
- Accepted November 23, 2012.
- © 2013 by the American Diabetes Association.
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