Effect of Peanut Shell Extract and Luteolin on Gut Microbiota and High-Fat Diet-Induced Sequelae of the Inflammatory Continuum in a Metabolic Syndrome-like Murine Model.

Background: Metabolic syndrome (MetS) is characterized by chronic inflammation, oxidative stress, and mitochondrial dysfunction. MetS is associated with increased intestinal permeability and dysbiosis. The objective of this study was to investigate the effects of peanut shell extract (PSE) and luteolin (LUT) on the kidneys, colon, and ileum in a MetS-like murine model. Methods: Thirty-six male Slc6a14y/- mice were divided into four groups: low-fat diet (LFD), high-fat diet (HFD), HFD + 200 mg PSE/kg BW (PSE, p.o.), and HFD + 100 mg LUT/kg BW (LUT, p.o.) for 4 months. Outcome measures included glucose homeostasis, intestinal permeability, gut microbiome composition, and mRNA gene expression of mitochondrial homeostasis and inflammation/oxidative stress in the kidneys, colon, and ileum. Results: HFD resulted in glucose dysregulation with hyperglycemia and insulin resistance. PSE and LUT improved insulin tolerance and beta-cell function. PSE and LUT mitigated HFD-increased serum lipopolysaccharide-binding protein concentration. Perturbations in the gut microbiome were associated with HFD, and PSE or LUT reversed some of these changes. Specifically, Phocaeicola vulgatus was depleted by HFD and reverted by PSE or LUT. Relative to the LFD group, the HFD group (1) upregulated mitochondrial fusion (MFN1, MFN2, OPA1), mitophagy (TLR4, PINK1, LC3B), and inflammation (NFκB, TNFα, IL6), and (2) downregulated mitochondrial fission (FIS1, DRP1), biosynthesis (PGC1α, NRF1, NRF2, TFAM), electron transport chain (complex I), and antioxidant enzyme (SOD1) in the kidneys, colon, and ileum. Conclusions: PSE and LUT reversed such HFD-induced changes in the aforementioned gene expression levels.