Abstract
Background: Insufficient treatment options are available for metabolic dysfunction-associated steatotic liver disease (MASLD). Flavonoids and topiramate have been studied for weight loss but need investigation into their effects on liver metabolism. This study's aim was to examine the effects of flavonoids or topiramate on glucose metabolic carbon flux in a cell culture model of steatosis. Methods: Steatosis was induced in HepG2 cells through exposure to oleic acid (OA, 0.5 mml/L) conjugated to bovine serum albumin (2:1). Additionally, 50% U(13)C-glucose was supplied in the medium as a stable isotope tracer. Cells were treated with DMSO, 10 μM of naringenin, morin, silibinin, or topiramate (44 μM) for 72 h. A non-steatotic, untreated HepG2 cell control was included. Cell extracts were analyzed by gas chromatography/mass spectrometry and mass isotopomer distribution analysis for glycogen synthesis, de novo fatty acid synthesis, tricarboxylic acid (TCA) cycle activity, and ribose synthesis. Groups were compared by ANOVA with Tukey's pair-wise testing. Results: Compared to untreated HepG2 controls, OA-exposed steatotic cells exhibited increased lipid accumulation by ORO staining (1.6-fold), enhanced palmitate de novo synthesis, reduced pyruvate carboxylase/pyruvate dehydrogenase (PC/PDH) ratio, and reduced ribose synthesis. Treatment with topiramate or silibinin ameliorated the lipid accumulation (1.3-fold) and mitigated enhancement of de novo synthesis. Morin-treated cells exhibited enhanced de novo synthesis but suppressed ribose synthesis. Conclusions: Potential mechanisms of reduced lipid accumulation by topiramate and silibinin may include suppression of palmitate de novo synthesis and a relative decrease in carbon flux through the PDH pathway. Further studies are needed on potential utility in MASLD based on their specific metabolic effects.