Functional lipids combination reverses Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) in rats through synergistic and pleiotropic mechanisms

Abstract

Background/objective

Cafeteria (CAF) diet-fed rats could be used as an experimental animal model for studying metabolic dysfunction-associated steatotic liver disease (MASLD). This study aimed to evaluate the potential effects of a combination of functional lipids (FL) on the reversal of CAF diet-induced MASLD and to investigate the metabolomic mechanisms underlying some specific metabolic dysfunctions associated with the hepatic disease.

Cafeteria (CAF) diet-fed rats could be used as an experimental animal model for studying metabolic dysfunction-associated steatotic liver disease (MASLD). This study aimed to evaluate the potential effects of a combination of functional lipids (FL) on the reversal of CAF diet-induced MASLD and to investigate the metabolomic mechanisms underlying some specific metabolic dysfunctions associated with the hepatic disease.

Methods

Male Wistar rats (Ethics Committee approval No. CE2021-85), were fed a CAF diet (90d) to induce SLD, obesity, and inflammation. Animals were then assigned to 5 dietary groups during 60 days: CAF diet, control diet (C; AIN-93M), or C supplemented with conjugated linoleic acid (CLA), Tocopherol-Phytosterol mixture (TP + PS), or their combination (cFL). SLD, obesity, inflammation, and lipid metabolism parameters were evaluated using biochemical, histological, nutriomic, and lipidomic approaches. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test. Statistical significance was set at P < 0.05.

Male Wistar rats (Ethics Committee approval No. CE2021-85), were fed a CAF diet (90d) to induce SLD, obesity, and inflammation. Animals were then assigned to 5 dietary groups during 60 days: CAF diet, control diet (C; AIN-93M), or C supplemented with conjugated linoleic acid (CLA), Tocopherol-Phytosterol mixture (TP + PS), or their combination (cFL). SLD, obesity, inflammation, and lipid metabolism parameters were evaluated using biochemical, histological, nutriomic, and lipidomic approaches. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test. Statistical significance was set at P < 0.05.

Results

Dietary FL mitigated CAF diet-induced nutriomic alterations, improving SLD, obesity, and inflammation. CLA showed the strongest effect on hepatic lipid accumulation, reducing hepatic triacylglycerol (TAG), Cholesterol (Chol), Collagen, and decreasing micro- and macrosteatosis. These bioactive effects were accompanied by reduced adiposity and inflammation. TP + PS exerted themost pronounced anti-inflammatory effects, lowering serum C-Reactive Protein (CRP) and proinflammatory oxylipins: 8-HETE and 12-oxo-HETE. In the liver, TP + PS reduced 5-HETE, 12-HETE, and 12-oxo-HETE levels, which significantly correlated to reductions in both micro- and macro-steatosis, and decreased pro- inflammatory fatty acids (FA). Notably, cFL reduced both micro- and macro-steatosis and enhanced β-oxidation (PPARα: 59% and CPT1a: 88%), and VLDL-TG export capacity (MTTP: 60%), while decreasing FA transport (FATP2: −29%; FATP5: −19%) and esterification (DGAT2: −29%). The mitigation of liver disease was accompanied by reductions in body weight gain (−9%), abdominal circumference (−12%), visceral adiposity (−11%), proinflammatory oxylipins: TxB2 (−52%), PGE2 (−38%), PGD2 (−60%), 5-HETE (−34%), 8-HETE (−39%), 12-HETE (−58%), 15-oxo-HETE (−79%) and 13-HODE (−69%), and an improved hepatic n-3/n-6 LC-PUFA ratio.

Dietary FL mitigated CAF diet-induced nutriomic alterations, improving SLD, obesity, and inflammation. CLA showed the strongest effect on hepatic lipid accumulation, reducing hepatic triacylglycerol (TAG), Cholesterol (Chol), Collagen, and decreasing micro- and macrosteatosis. These bioactive effects were accompanied by reduced adiposity and inflammation. TP + PS exerted themost pronounced anti-inflammatory effects, lowering serum C-Reactive Protein (CRP) and proinflammatory oxylipins: 8-HETE and 12-oxo-HETE. In the liver, TP + PS reduced 5-HETE, 12-HETE, and 12-oxo-HETE levels, which significantly correlated to reductions in both micro- and macro-steatosis, and decreased pro- inflammatory fatty acids (FA). Notably, cFL reduced both micro- and macro-steatosis and enhanced β-oxidation (PPARα: 59% and CPT1a: 88%), and VLDL-TG export capacity (MTTP: 60%), while decreasing FA transport (FATP2: −29%; FATP5: −19%) and esterification (DGAT2: −29%). The mitigation of liver disease was accompanied by reductions in body weight gain (−9%), abdominal circumference (−12%), visceral adiposity (−11%), proinflammatory oxylipins: TxB2 (−52%), PGE2 (−38%), PGD2 (−60%), 5-HETE (−34%), 8-HETE (−39%), 12-HETE (−58%), 15-oxo-HETE (−79%) and 13-HODE (−69%), and an improved hepatic n-3/n-6 LC-PUFA ratio.

Conclusion

The combination of FL (CLA + TP + PS) synergistically reversed MASLD through a pleiotropic mechanism, including the upregulation of genes involved in hepatic β-oxidation and VLDL-TG secretion, along with an anti-inflammatory milieu characterized by reduced levels of pro-inflammatory mediators.

The combination of FL (CLA + TP + PS) synergistically reversed MASLD through a pleiotropic mechanism, including the upregulation of genes involved in hepatic β-oxidation and VLDL-TG secretion, along with an anti-inflammatory milieu characterized by reduced levels of pro-inflammatory mediators.