Daily Endocrinology Research Analysis
Analyzed 91 papers and selected 3 impactful papers.
Summary
A Cell study uncovers a mitochondrial PEP shuttle mediated by SLC25A35 that drives glycerolipid synthesis; hepatic inhibition improves steatosis and glucose homeostasis in obese mice, highlighting a druggable metabolic node. A large multicenter registry refines the phenotypic spectrum and risk stratification in SLC40A1-related iron overload, linking higher transferrin saturation to fibrosis and questioning routine phlebotomy. A nationwide Danish cohort suggests periconceptional GLP-1RA exposure is linked to preterm birth only when used for diabetes, implicating underlying disease rather than the drug.
Research Themes
- Mitochondrial metabolite shuttles and lipid metabolism
- Genotype-phenotype stratification in iron overload disorders
- Periconceptional safety of GLP-1 receptor agonists
Selected Articles
1. Mitochondrial control of glycerolipid synthesis by a PEP shuttle.
This study identifies SLC25A35 as a mitochondrial PEP exporter that fuels glyceroneogenesis and glycerolipid synthesis. Hepatic inhibition of SLC25A35 in obese mice alleviated steatosis and improved systemic glucose homeostasis, nominating a druggable mitochondrial node for metabolic disease.
Impact: It unveils a previously unrecognized mitochondrial metabolite shuttle with direct translational potential for NAFLD and type 2 diabetes. The mechanistic depth and therapeutic proof-of-concept position this as a high-impact discovery.
Clinical Implications: SLC25A35 emerges as a therapeutic target to limit hepatic glycerolipid synthesis, potentially treating steatosis and improving glycemic control. Biomarker development around hepatic PEP flux may aid patient stratification.
Key Findings
- SLC25A35 mediates pH gradient–dependent mitochondrial PEP export, enabling glyceroneogenesis.
- Loss of SLC25A35 in adipocytes reduces glycerol-3-phosphate production and glycerolipid synthesis.
- Hepatic inhibition of SLC25A35 in obese mice alleviates steatosis and improves systemic glucose homeostasis.
Methodological Strengths
- Convergent mechanistic evidence from reconstitution, structural studies, and in vivo models.
- Causal perturbations (loss-of-function and hepatic inhibition) linked to metabolic phenotypes.
Limitations
- Preclinical data without human interventional validation.
- Tissue specificity and potential off-target effects of manipulating SLC25A35 remain to be defined.
Future Directions: Develop selective SLC25A35 modulators, validate effects in human hepatocytes and organoids, and evaluate safety/efficacy in metabolic disease models en route to early-phase clinical trials.
Mitochondria provide a variety of metabolites, in addition to ATP, to meet cell-specific needs. One such metabolite is phosphoenolpyruvate (PEP), which contains a higher-energy phosphate bond than ATP and has diverse biological functions. However, how mitochondria-generated PEP is delivered to the cytosol and fulfills cell-specific requirements remains elusive. Here, we show that SLC25A35 regulates mitochondrial PEP efflux and glyceroneogenesis in lipogenic cells that utilize the pyruvate-to-PEP bypass. Reconstitution and structural studies demonstrated PEP transport by SLC25A35 in a pH gradient-dependent manner. Loss of SLC25A35 in adipocytes impaired the conversion of mitochondrial PEP into glycerol-3-phosphate, thereby reducing glycerolipid synthesis.
2. Characterization of ferroportin disease and SLC40A1-related hemochromatosis - Results from the EASL non-HFE registry.
Across 95 registry cases and 363 literature cases, SLC40A1 variants produced a spectrum from FD to SLC40A1-HC. Elevated TSAT (>45%) signaled higher fibrosis risk, while life expectancy was comparable to HFE-HC and routine phlebotomy did not alter survival, supporting individualized management.
Impact: Provides the most detailed contemporary phenotyping of SLC40A1 disorders, offers risk stratification by TSAT, and challenges routine phlebotomy assumptions—directly informing clinical pathways for rare iron overload syndromes.
Clinical Implications: Differentiate FD from SLC40A1-HC using TSAT and organ iron distribution; prioritize fibrosis surveillance when TSAT >45%. Reassess blanket phlebotomy strategies and tailor interventions based on phenotype and risk.
Key Findings
- FD phenotype occurred in 65.5% and patients with FD were younger and more often female than SLC40A1-HC.
- Higher hepatic and splenic iron concentrations with SLC40A1 variants compared to HFE-HC; variants near the metal binding site more often showed high TSAT.
- TSAT >45% was associated with higher fibrosis risk; life expectancy was similar to HFE-HC and routine phlebotomies did not change survival.
Methodological Strengths
- Prospective, multicenter registry with standardized phenotyping and a large comparative HFE-HC cohort.
- Augmented power via systematic literature synthesis to capture rare variant presentations.
Limitations
- Heterogeneity and potential selection bias from combining registry and literature-derived cases.
- Observational design without randomized treatment comparisons limits causal inference on phlebotomy effects.
Future Directions: Prospective interventional studies to define TSAT thresholds for therapy, evaluate noninvasive fibrosis biomarkers, and develop individualized phlebotomy or chelation strategies.
BACKGROUND & AIMS: Pathogenic variants in the cellular iron exporter ferroportin (SLC40A1) cause hepatic and splenic iron overload. Low to normal transferrin saturation (TSAT) and iron accumulation in Kupffer cells with high splenic iron distinguish ferroportin disease (FD) from SLC40A1-related hemochromatosis (SLC40A1-HC), which are both caused by variants in SLC40A1. The aim of our study was to describe pathogenic mutations in SLC40A1, phenotypic variability in affected patients and compare outcomes with HFE-related hemochromatosis (HFE-HC). METHODS: The international EASL non-HFE hemochromatosis patient registry prospectively collected clinical, radiological, biochemical, and genetic data for 95 patients with SLC40A1 variants from six centers. Additionally, 363 patients were identified by a systematic literature review. As a comparator, 603 patients diagnosed with HFE-HC were included. RESULTS: The FD phenotype presented in 65.5% of affected individuals. Patients with FD were younger at diagnosis and more often female than those with SLC40A1-HC.
3. Periconceptional GLP-1 receptor agonist exposure and obstetric outcomes: a Danish nationwide cohort study.
In 756,636 pregnancies, periconceptional liraglutide/semaglutide exposure was associated with preterm birth only among women treated for diabetes, not among those using these drugs for weight management. Propensity-matched analyses suggest underlying diabetes, rather than GLP-1RA exposure per se, may drive the risk.
Impact: Amid rapidly expanding GLP-1RA use in reproductive-age women, these data refine counselling by separating drug effects from diabetes-related risk, directly informing preconception planning.
Clinical Implications: Continue to avoid GLP-1RAs in pregnancy; for inadvertent periconceptional exposure without diabetes, risk of preterm birth may not be elevated. Optimize glycemic control preconception in women with diabetes to mitigate prematurity risk.
Key Findings
- Among 756,636 singleton pregnancies, 529 had periconceptional GLP-1RA exposure identified from national prescription data.
- After propensity score matching, preterm birth risk was elevated with liraglutide/semaglutide when used for diabetes but not when used for weight management.
- No consistent signal for other obstetric complications after adjustment; observational limitations remain.
Methodological Strengths
- Nationwide registry-based cohort with very large sample size and robust propensity score matching.
- Stratification by indication (diabetes vs weight management) to address confounding by indication.
Limitations
- Exposure based on prescription redemption without adherence data; potential residual confounding.
- Limited long-term follow-up for recent semaglutide weight-loss prescriptions; observational design precludes causality.
Future Directions: Link dispensing with adherence data, incorporate glycemic variability metrics, and prospectively evaluate maternal-fetal outcomes in preconception optimization strategies.
STUDY QUESTION: What is the association between periconceptional GLP-1 receptor agonist exposure and risk of obstetric complications? SUMMARY ANSWER: Periconceptional GLP-1 receptor agonist exposure was associated with increased preterm birth risk when used for diabetes treatment (liraglutide aOR 1.70, 95% CI 1.17-2.48; semaglutide aOR 1.84, 95% CI 1.24-2.7) but not for weight management, suggesting the underlying diabetes rather than the medication may be the causal factor. WHAT IS KNOWN ALREADY: GLP-1 receptor agonists are rapidly expanding in use among reproductive-age women for diabetes and obesity treatment. While not approved for use in pregnancy, inadvertent periconceptional exposure occurs frequently. Limited safety data exist, with recent small studies suggesting no increased risk of major congenital malformations, but comprehensive obstetric outcome data remain lacking. STUDY DESIGN SIZE DURATION: This nationwide observational cohort study used data from Danish health registries from October 2009 through December 2023. We analyzed 756 636 singleton pregnancies among 480 231 women, with 529 pregnancies having periconceptional GLP-1 receptor agonist exposure.