Flavonoid-rich Chardonnay grape seed flour supplementation ameliorates diet-induced visceral adiposity, insulin resistance, and glucose intolerance via altered adipose tissue gene expression

The effect of flavonoid-rich wine grape seed flour, a byproduct of winemaking, on global adipose tissue gene expression and obesity-induced insulin resistance was assessed in high fat (HF) diet-induced obese (DIO) mice. DIO mice were fed HF diet supplemented with either partially defatted Chardonnay grape seed flour (ChrSd) or microcrystalline cellulose (MCC, control) for 5 weeks. ChrSd diet suppressed the HF diet-induced increase in total body, liver, and adipose tissue weights with a significant decrease in feed efficiency. ChrSd intake significantly lowered the 2-h insulin and glucose areas under the curve suggesting that ChrSd improves insulin sensitivity and glucose metabolism. Gene expression profiling analysis of adipose tissue from mice fed a ChrSd diet, by exon microarray and RT-PCR, revealed a down-regulation of genes related to oxidative stress, inflammation, immune response, protein carbonylation, and fatty acid synthesis. Conversely, genes related to the scavenging of free radicals, antioxidants, insulin sensitivity, and fatty acid oxidation, were up-regulated. Pathway analysis of microarray data identified genes related to innate immune response, inflammatory response, and infectious disease as being differentially regulated by the ChrSd diet. Thus, ChrSd ameliorates HF-induced obesity, insulin resistance, and glucose intolerance in DIO mice by modulating expression of genes in adipose tissue.