Daily Endocrinology Research Analysis
Three impactful endocrinology/metabolism studies stood out today. A Science paper identifies a symbiotic filamentous gut fungus that ameliorates MASH via a secondary metabolite–CerS6–ceramide axis. A PNAS study pinpoints cholesterol within liver lipid droplets (without increases in total hepatic cholesterol) as an early determinant of steatohepatitis, while a large JCEM cohort links both systemic and locally administered corticosteroids to long-term gains in weight and waist circumference.
Summary
Three impactful endocrinology/metabolism studies stood out today. A Science paper identifies a symbiotic filamentous gut fungus that ameliorates MASH via a secondary metabolite–CerS6–ceramide axis. A PNAS study pinpoints cholesterol within liver lipid droplets (without increases in total hepatic cholesterol) as an early determinant of steatohepatitis, while a large JCEM cohort links both systemic and locally administered corticosteroids to long-term gains in weight and waist circumference.
Research Themes
- Microbiome–lipid signaling axis in metabolic liver disease
- Lipid droplet cholesterol as an early driver of steatohepatitis
- Medication-associated adiposity and metabolic risk (corticosteroids)
Selected Articles
1. A symbiotic filamentous gut fungus ameliorates MASH via a secondary metabolite-CerS6-ceramide axis.
This mechanistic study systematically isolated and characterized gut fungi and identified a symbiotic filamentous species that ameliorates MASH via a secondary metabolite acting on a CerS6–ceramide pathway. The work links a specific mycobiome member to host sphingolipid metabolism, providing a causal microbiome–lipid signaling axis in steatohepatitis.
Impact: First demonstration of a gut fungal symbiont modulating host ceramide synthesis to ameliorate MASH establishes a new therapeutic axis beyond bacteria. It reframes microbiome-targeted therapies toward mycobiome-based interventions.
Clinical Implications: Suggests potential for mycobiome-based or metabolite-based therapeutics (e.g., targeting CerS6–ceramide signaling) for MASH. It motivates biomarker development around ceramide species and fungal metabolites.
Key Findings
- Systematic isolation and characterization of gut fungi identified a symbiotic filamentous species relevant to metabolic disease.
- This fungus ameliorates MASH via a secondary metabolite that modulates a CerS6–ceramide pathway.
- Establishes a causal microbiome–host lipid signaling axis linking the gut mycobiome to hepatic sphingolipid metabolism.
Methodological Strengths
- Systematic isolation/characterization of gut fungi with mechanistic linkage to host lipid metabolism
- Clear molecular pathway (CerS6–ceramide) connecting microbial metabolite to disease phenotype
Limitations
- Preclinical mechanistic evidence; human validation not detailed in the provided text
- Abstract details are truncated, limiting insight into experimental breadth and replication
Future Directions: Validate the CerS6–ceramide axis in human MASH cohorts; identify and characterize the fungal metabolite; develop mycobiome/metabolite-based interventions and biomarkers.
The gut microbiota is known to be associated with a variety of human metabolic diseases, including metabolic dysfunction-associated steatohepatitis (MASH). Fungi are increasingly recognized as important members of this community; however, the role of fungal symbionts in metabolic diseases is unknown. We have systematically isolated and characterized gut fungi, identifying
2. Liver lipid droplet cholesterol content is a key determinant of metabolic dysfunction-associated steatohepatitis.
Using dietary, molecular, and genetic models, the study shows that cholesterol accumulation within hepatic lipid droplets increases rapidly (within 5 days) during steatohepatitis development, despite unchanged total hepatic cholesterol. Early fibrosis markers accompanied this shift, positioning lipid droplet cholesterol as a key pathogenic driver.
Impact: Reframes lipid toxicity in MASH from total hepatic cholesterol to compartmentalized lipid droplet cholesterol, creating specific therapeutic and biomarker targets.
Clinical Implications: Supports development of diagnostics quantifying lipid droplet cholesterol and therapies targeting droplet cholesterol handling to prevent early fibrogenesis.
Key Findings
- In CDAHFD-fed mice, steatohepatitis with early fibrosis markers emerged within 5 days alongside increased cholesterol in liver lipid droplets.
- Total hepatic cholesterol content did not change despite a marked rise in lipid droplet cholesterol.
- Multiple dietary, molecular, and genetic models converged to implicate lipid droplet cholesterol as a pathogenic determinant.
Methodological Strengths
- Use of complementary dietary, molecular, and genetic models to triangulate causality
- Early temporal resolution capturing pathogenic lipid changes within days
Limitations
- Target(s) of antisense oligonucleotides not specified in the provided abstract text
- Translational validation in human MASH populations not detailed
Future Directions: Quantify lipid droplet cholesterol in human MASH; define molecular regulators of droplet cholesterol trafficking; test pharmacologic strategies to reduce droplet cholesterol early in disease.
Metabolic dysfunction-associated steatohepatitis (MASH) represents a progressive form of steatotic liver disease which increases the risk for fibrosis and advanced liver disease. The accumulation of discrete species of bioactive lipids has been postulated to activate signaling pathways that promote inflammation and fibrosis. However, the key pathogenic lipid species is a matter of debate. We explored candidates using various dietary, molecular, and genetic models. Mice fed a choline-deficient L-amino acid-defined high-fat diet (CDAHFD) developed steatohepatitis and manifested early markers of liver fibrosis associated with increased cholesterol content in liver lipid droplets within 5 d without any changes in total liver cholesterol content. Treating mice with antisense oligonucleotides against
3. Corticosteroid Use and Long-Term Changes in Weight and Waist Circumference: The Lifelines Cohort Study.
In 81,361 adults followed for ~3.9 years, any new corticosteroid use was associated with greater annual weight gain; local corticosteroid initiation showed similar effects. New systemic corticosteroid use increased waist circumference, while discontinuation decreased it. Effects were most evident in women and those with BMI ≥25 kg/m2.
Impact: Provides robust longitudinal evidence that even locally administered corticosteroids contribute to long-term adiposity metrics, informing risk–benefit assessments and deprescribing strategies.
Clinical Implications: Clinicians should monitor weight and waist circumference in corticosteroid users (including local forms), particularly in women and patients with overweight/obesity; consider lowest effective doses, steroid-sparing alternatives, and timely discontinuation when feasible.
Key Findings
- Any new corticosteroid use associated with greater annual weight gain versus nonuse (β 0.034 kg/year, P=.021); local corticosteroid initiation showed similar effect (β 0.037 kg/year, P=.017).
- New systemic corticosteroid use increased waist circumference (β 0.200 cm/year, P<.001), while discontinuation reduced it (β -0.078 cm/year, P=.028).
- Effects were pronounced in women and individuals with BMI ≥25 kg/m2; no short-term (weeks) weight-inducing effects post-initiation were observed.
Methodological Strengths
- Large population-based cohort (n=81,361) with longitudinal follow-up (~3.9 years)
- Stratified and sensitivity analyses (sex, BMI); mixed-effects models for short-term dynamics
Limitations
- Observational design with potential residual confounding (indication, dosing, adherence details limited)
- Medication exposure based on self-report/reporting intervals may undercapture dose-response granularity
Future Directions: Define dose–response thresholds across local/systemic corticosteroids; evaluate steroid-sparing regimens and timing of deprescribing on adiposity and metabolic outcomes.
CONTEXT: The use of corticosteroids (CS) has been associated with higher body mass index (BMI) and waist circumference (WC) in cross-sectional studies. However, longitudinal data are scarce, particularly for locally administered forms. DESIGN: We analyzed weight and waist circumference changes in 81 361 Lifelines Cohort Study participants (mean age 46.3 years, mean BMI 26.0 kg/m2, 41% male, mean follow-up 3.9 years) via linear regression. Sensitivity analyses included stratification by sex and BMI. Short-term weight changes post-start were assessed in a subset using linear mixed-effect models. RESULTS: We found 23.8% CS users during the study period. Individuals reporting any new use of CS gained significantly more weight compared to nonusers at follow-up (β .034 kg/year, P = .021), particularly among those initiating local CS use (β .037 kg/year, P = .017). Use of new systemic CS was associated with increased WC (β .200 cm/year, P < .001). Discontinuation of CS led to decreased WC (β -.078 cm/year, P = .028). These effects were particularly observed in female participants and individuals with BMI ≥25 kg/m2, but not in male participants and those with BMI < 25 kg/m2. Short-term weight-inducing effects of CS were not observed in the weeks after initiation of CS use. CONCLUSION: This study demonstrates that CS use, including locally administered forms, is associated with long-term increases in weight and WC, notably in female individuals and those with overweight or obesity. Discontinuing CS was linked to reductions in WC. These findings underscore the need to carefully assess chronic systemic and local CS use, as discontinuation could benefit obesity-related outcomes in certain patients.