Inhibitory effects of berry anthocyanins on palmitic acid- or lipopolysaccharide- induced inflammation in human preadipocytes

Abstract

Obesity is an inflammatory disease associated with the development and progression of chronic degenerative diseases including insulin resistance, cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), and cancer. Circulating free fatty acid (FFA) are known risk factors promoting inflammation that can lead to CVD. Pre/adipocytes are known storage of low grade inflammatory biomarkers associated with obesity. However, the effects of dietary anthocyanins on inflammatory biomarkers in preadipocytes have not been reported. Berries are rich sources of naturally occurring antioxidant polyphenolics. There is increasing interest in the ability of berry anthocyanins to provide health benefits against obesity. Anthocyanins were isolated from blueberry, blackberry, cranberry and black currant and analyzed by spectrophotometry and liquid chromatography. The objective of this study was to test the effect of berry anthocyanins on palmitic acid (PA)-induced inflammatory biomarkers in human preadipocytes. Comparison was made with the effect of berry anthocyanins on lipopolysaccharide (LPS)-induced inflammation in similar human preadipocytes. Preadipocytes from obese women were incubated with different concentrations (10-40ìM) of berry anthocyanins for 24 h followed by addition of 100 ìM PA and additional incubation for 24h or 100ng/ml of LPS for 8 h. In another treatment, preadipocytes were incubated with 100 ìM PA for 24h or 100ng/ml of LPS for 8 h and then incubated with 10-40ìM anthocyanins for 24h. All incubations were performed at 37 °C in a 5% CO2 humidified incubator. Pro-inflammatory cytokines IL-6, IL-8 and MCP-1 were analyzed in conditioned preadipocyte media by ELISA. NF-êB and COX-2 from preadipocyte lysates were analyzed by Western Blot. PA or LPS induced up-regulation of the pro-inflammatory biomarkers. Berry anthocyanins significantly inhibited PA- or LPS-induced inflammation when anthocyanins were added to the preadipocytes prior to PA or LPS addition. However, the same anthocyanins were weak inhibitors of PA- or LPS-induced inflammation when preadipocytes were first incubated with LPS or PA. The results of our investigation show that berry anthocyanins may be effective in preventing PA- or LPS-induced low-grade inflammation in preadipocytes.