Weight-independent effects of Roux-en-Y gastric bypass surgery on remission of nonalcoholic fatty liver disease in mice

Regulating bile acids signaling for NAFLD: molecular insights and novel therapeutic interventions

Nonalcoholic fatty liver disease (NAFLD) emerges as the most predominant cause of liver disease, tightly linked to metabolic dysfunction. Bile acids (BAs), initially synthesized from cholesterol in the liver, undergo further metabolism by gut bacteria. Increasingly acknowledged as critical modulators of metabolic processes, BAs have been implicated as important signaling molecules. In this review, we will focus on the mechanism of BAs signaling involved in glucose homeostasis, lipid metabolism, energy expenditure, and immune regulation and summarize their roles in the pathogenesis of NAFLD. Furthermore, gut microbiota dysbiosis plays a key role in the development of NAFLD, and the interactions between BAs and intestinal microbiota is elucidated. In addition, we also discuss potential therapeutic strategies for NAFLD, including drugs targeting BA receptors, modulation of intestinal microbiota, and metabolic surgery.

Restricting bioenergetic efficiency enhances longevity and mitochondrial redox capacity in Drosophila melanogaster

Mitochondria are essential for survival and as such, impairments in organelle homeostasis significantly accelerate age-related morbidity and mortality. Here, we determined the contribution of bioenergetic efficiency to life span and health span in Drosophila melanogaster utilizing the mitochondrial uncoupler BAM15. Life span was determined in flies fed a normal diet (ND) or high fat diet (HFD) supplemented with vehicle or BAM15. Locomotor function was determined by negative geotaxis assay in middle-aged flies fed vehicle or BAM15 under ND or HFD conditions. Redox capacity (high-resolution respirometry/fluorometry), citrate synthase (enzyme activity), mtDNA content (qPCR), gene expression (qPCR), and protein expression (western blot) were assessed in flight muscle homogenates of middle-aged flies fed vehicle or BAM15 ND. The molar ratio of H2O2 and O2 (H2O2:O2) in a defined respiratory state was calculated as a measure of redox balance. BAM15 extended life span by 9% on ND and 25% on HFD and improved locomotor activity by 125% on ND and 53% on HFD. Additionally, BAM15 enhanced oxidative phosphorylation capacity supported by pyruvate + malate, proline, and glycerol 3-phosphate. Concurrently, BAM15 enhanced the mitochondrial H2O2 production rate, reverse electron flow from mitochondrial glycerol-3-phosphate dehydrogenase (mGPDH) to Complex I, mGPDH, and Complex I without altering the H2O2:O2 ratio. BAM15 upregulated transcriptional signatures associated with mitochondrial function and fitness as well as antioxidant defense. BAM15-mediated restriction of bioenergetic efficiency prolongs life span and health span in Drosophila fed a ND or HFD. Improvements in life span and health span in ND were supported by synergistic enhancement of muscular redox capacity.

Mid-term Effects of Bariatric Surgery on Metabolic Dysfunction-Associated Fatty Liver Disease Remission and Predictive Factors: A Prospective Study with a Focus on Non-invasive Diagnosis

PURPOSE

Non-alcoholic fatty liver disease (NAFLD), now termed metabolic dysfunction-associated fatty liver disease (MAFLD), is a growing health concern associated with obesity and type 2 diabetes. Bariatric surgery offers potential benefits, but its impact on MAFLD remains incompletely understood, with scarce long-term follow-up prospective studies. Moreover, being liver biopsy the gold standard for liver condition measurement, the need for non-invasive techniques that allow the assessment of MAFLD development after bariatric surgery is imperative. OWLiver® Care and OWLiver® represent two serum lipidomic tests, featuring panels comprising 11 and 20 triglycerides, respectively.

MATERIALS AND METHODS

We conducted a prospective study involving 80 Caucasians to assess the effects of bariatric surgery on MAFLD using non-invasive diagnostics and to identify baseline predictors of MAFLD remission. Serum samples were collected before surgery and at a 3-year follow-up.

RESULTS

After 3 years, the proportion of patients exhibiting a healthy liver escalated from 5.0% at baseline to 26.3%. Conversely, the percentage of steatohepatitis declined from 35.1% to a mere 7.6%. Younger age, female gender, and the absence of type 2 diabetes were associated with MAFLD remission. However, age stood as the only independent variable associated with this favorable liver evolution (R2 = 0.112).

CONCLUSION

Bariatric surgery demonstrates mid-term benefits in improving MAFLD, with younger age as a baseline predictor of remission. Non-invasive diagnostic methods, like OWLiver®, are valuable tools for monitoring MAFLD evolution. Further research with larger populations and longer follow-up periods is warranted to refine personalized treatment approaches.