Differential fatty acid profile in adipose and non-adipose tissues in obese mice

Obesity is a metabolic disease characterized by chronic inflammation. Early studies indicated that adipose tissue from obese mice contains more saturated fatty acids and that the saturated fatty acids activate TLR4-mediated inflammatory signaling, which contributes to inflammation in adipose tissue. In this study, we determined fatty acid profile in non-adipose tissues from obese (db/db) mice and compared with that from lean mice. Unexpectedly, in contrast to a significant increase in saturated and decrease in unsaturated fatty acid in adipose tissue from obese mice, the non-adipose tissues from obese mice exhibited a significant decrease in saturated and increase in unsaturated fatty acid compared with that from lean mice. The liver from obese mice had a 15% and 32% decrease in palmitic acid and stearic acid, and a 20% increase in linoleic acid; the spleen had a 32% and 60% decrease in palmitic acid and stearic acid, and a 70% and 50% increase in oleic acid and linoleic acid; and the pancreas had a 50% and 75% decrease in palmitic acid and stearic acid, and a 130% and 113% increase in oleic acid and linoleic acid. These data suggest that, different from adipose tissue where elevated saturated fatty acids contributes to inflammation, fatty acids per se in non-adipose tissues such as liver, spleen and pancreas may not contribute to inflammatory responses in obese mice.