The Different Insulin-Sensitising and Anti-Inflammatory Effects of Palmitoleic Acid and Oleic Acid in a Prediabetes Model

Figure 6

Final scheme of different putative involvement of oleic (OA) and palmitoleic (POA) acid on metabolic effects in peripheral tissues associated with insulin sensitivity (IS) improvement and inflammatory amelioration. OA supplementation (a) in hereditary hypertriglyceridemic (HHTg) rats affected mainly n6-polyunsaturated fatty acid (n6-PUFA) metabolism—especially arachidonic acid (AA) metabolism. OA-treated rats exhibited not only decreased AA profiles but also decreased proinflammatory AA-derived metabolites (HETEs) in peripheral tissues, which could ultimately reduce chronic inflammation. Slightly increased fatty acid desaturase (FADS1) gene expression after OA along with increased adiponectin production by adipose tissue was reflected in slightly improved IS of visceral adipose tissue (VAT). On the other hand, POA supplementation (b) in HHTg rats mainly affected the incorporation of n3-PUFA into membrane phospholipids of the skeletal muscle and VAT and markedly decreased toxic lipid accumulation into peripheral tissues, which could contribute to increased membrane fluidity. Considerably increased FADS1 gene expression together with elevated adiponectin production by VAT led to a significant increase in circulating adiponectin and omentin levels. These alterations could contribute to improvement of IS of both muscle and VAT. In addition to the insulin-sensitising effect, POA-treated rats showed markedly decreased proinflammatory cytokine production by VAT. All these changes in the adipose tissue, together with markedly elevated basal lipolysis, gene expression of Lpl, and fatty acid (FA) reesterification, indicate a significant increase in metabolic activity of VAT and lead to the designation of POA as a lipokine. Data are expressed as ; for each experimental group. Differences were analyzed using one-way ANOVA and LSD-Fisher’s post hoc test. denotes significance reflecting the effect of POA vs. control (c); # denotes significance reflecting the effect of OA vs. C; ↑ denotes significance reflecting the effect of OA/POA therapy vs. the C group. , , ^##, ^###, ^↑, ^↑↑, and .