Totum‐448 Improves <scp>MASLD</scp> and Modulates Microbiota in Hamsters: Dose–Response Study and Effects of Supplementation Cessation

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global condition linked to obesity. Totum-448, a polyphenol-rich blend of five plant extracts and choline, was developed to target MASLD progression. This study evaluated the dose-dependent effects of Totum-448 and their sustainability after supplementation cessation on MASLD features and cecal microbiota. Male hamsters were fed a normal diet, a Western diet (WD), or WD supplemented with Totum-448 (3.5% or 5% w/w) for 12 weeks (dose-response study). A parallel 18-week on/off study included 12 weeks of Totum-448 (5% w/w) followed by a 6-week cessation period. Totum-448 dose-dependently reduced hepatic and circulating triglycerides, total cholesterol, and free fatty acids, independently of any changes in body composition. Gene markers of liver inflammation (<i>Tgfb1</i>, <i>Il1b, Ccl2</i>, <i>Il6</i>) and fibrosis (<i>Col3a1, Vcam</i>) were downregulated with the highest dose of Totum-448 only. Supplementation cessation led to a gradual rebound in serum and liver lipid levels and in relative expression of gene markers of hepatic inflammation and fibrosis, resulting in the loss of the majority of the benefits conferred by Totum-448, although partial effects on hepatic steatosis and hepatocyte ballooning were maintained. Cecal microbiota analysis revealed modulation of the relative abundance of <i>Acetatifactor</i>, <i>Alloprevotella</i>, <i>Lactobacillus</i>, and <i>Lawsonibacter</i>, with identified correlations with certain metabolic outcomes. In conclusion, Totum-448 demonstrated dose-dependent improvements in key MASLD features in WD-fed hamsters which gradually diminished after supplementation stopped. These findings underscore its therapeutic potential in MASLD management. The correlations with microbiota changes suggest a possible gut-liver axis role in its effects.