A Polyphenol-Rich Cranberry Extract Reverses Insulin Resistance and Hepatic Steatosis Independently of Body Weight Loss.
OBJECTIVE: Previous studies have reported that polyphenol-rich extracts from various sources can prevent obesity and associated gastro-hepatic and metabolic disorders in diet-induced obese (DIO) mice. However, whether such extracts can reverse obesity-linked metabolic alterations remains unknown. In the present study, we aimed to investigate the potential of a polyphenol-rich extract from cranberry (CE) to reverse obesity and associated metabolic disorders in DIO-mice. METHODS: Mice were pre-fed either a Chow or a High Fat-High Sucrose (HFHS) diet for 13 weeks to induce obesity and then treated either with CE (200mg/kg, Chow+CE, HFHS+CE) or vehicle (Chow, HFHS) for 8 additional weeks. RESULTS: CE did not reverse weight gain or fat mass accretion in Chow- or HFHS-fed mice. However, HFHS+CE fully reversed hepatic steatosis and this was linked to upregulation of genes involved in lipid catabolism (e.g., PPARalpha) and downregulation of several pro-inflammatory genes (eg, COX2, TNFalpha) in the liver. These findings were associated with improved glucose tolerance and normalization of insulin sensitivity in HFHS+CE mice. The gut microbiota of HFHS+CE mice was characterized by lower Firmicutes to Bacteroidetes ratio and a drastic expansion of Akkermansia muciniphila and, to a lesser extent, of Barnesiella spp, as compared to HFHS controls. CONCLUSIONS: Taken together, our findings demonstrate that CE, without impacting body weight or adiposity, can fully reverse HFHS diet-induced insulin resistance and hepatic steatosis while triggering A. muciniphila blooming in the gut microbiota, thus underscoring the gut-liver axis as a primary target of cranberry polyphenols.