| Summary: | Obesity is an immunometabolic disease associated with chronic inflammation and the dysregulation of pro- and anti-inflammatory cytokines. One hallmark of obesity is reduced concentrations of the anti-inflammatory adipokine, adiponectin. Pharmacologic doses of niacin produce multiple metabolic benefits, including attenuating high-fat diet (HFD)-induced adipose tissue inflammation and increasing adiponectin concentrations. To determine if adiponectin mediates the anti-inflammatory effects of niacin, male C57BL/6J (WT) and adiponectin null (<i>Adipoq</i><sup>-/-</sup>) mice were maintained on a low-fat diet (LFD) or HFD for 6 weeks, before being administered either vehicle or niacin (360 mg/kg/day) for 5 weeks. HFD-fed mice had increased expression of genes associated with macrophage recruitment (<i>Ccl2</i>) and number (<i>Cd68</i>), and increased crown-like structure (CLS) number in adipose tissue. While niacin attenuated <i>Ccl2</i> expression, there were no effects on <i>Cd68</i> or CLS number. The absence of adiponectin did not hinder the ability of niacin to reduce <i>Ccl2</i> expression. HFD feeding increased gene expression of inflammatory markers in the adipose tissue of WT and <i>Adipoq<sup>-/-</sup></i> mice. While niacin tended to decrease the expression of inflammatory markers in WT mice, niacin increased their expression in HFD-fed <i>Adipoq<sup>-/-</sup></i> mice. Therefore, our results indicate that the absence of adiponectin alters the effects of niacin on markers of adipose tissue inflammation in HFD-fed mice, suggesting that the effects of niacin on tissue cytokines may involve adiponectin.
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