Daily Endocrinology Research Analysis
Top advances span mechanistic, clinical, and causal-inference endocrinology. A JCI study identifies the chromatin remodeler BAF60a as a key regulator of β cell glucose sensing and GLP-1 responsiveness. A meta-analysis in type 1 diabetes shows once-weekly basal insulin matches HbA1c of daily analogues but increases severe hypoglycemia. Mendelian randomization plus RCT synthesis challenges a causal role of liver fat in hyperglycemia.
Summary
Top advances span mechanistic, clinical, and causal-inference endocrinology. A JCI study identifies the chromatin remodeler BAF60a as a key regulator of β cell glucose sensing and GLP-1 responsiveness. A meta-analysis in type 1 diabetes shows once-weekly basal insulin matches HbA1c of daily analogues but increases severe hypoglycemia. Mendelian randomization plus RCT synthesis challenges a causal role of liver fat in hyperglycemia.
Research Themes
- Epigenetic control of β-cell function and incretin responsiveness
- Safety-efficacy balance of once-weekly basal insulin in type 1 diabetes
- Causal role of hepatic steatosis in glycaemic traits re-evaluated
Selected Articles
1. BAF60a-dependent chromatin remodeling preserves β cell function and contributes to the therapeutic benefits of GLP-1R agonists.
Across mouse, nonhuman primate, and human β cells, BAF60a maintains biphasic GSIS and glucose homeostasis by orchestrating chromatin accessibility with Nkx6.1. A human BAF60a V278M variant and a knock-in mouse model corroborate causality. BAF60a deficiency lowers GLP-1R/GIPR expression, blunting GLP-1R agonist insulinotropic effects, linking epigenetics to incretin pharmacodynamics.
Impact: Reveals a previously unappreciated epigenetic regulator of β-cell stimulus-secretion coupling with direct implications for incretin therapy responsiveness. Integrates multi-species models and human genetics, advancing mechanistic understanding and precision endocrinology.
Clinical Implications: BAF60a status may predict or modulate response to GLP-1R agonists; targeting chromatin remodeling could preserve β-cell function under metabolic stress. Genetic or epigenetic profiling might inform incretin therapy selection.
Key Findings
- BAF60a sustains biphasic GSIS and prevents β-cell dysfunction in metabolic stress; loss impairs GSIS and glucose tolerance.
- BAF60a interacts with Nkx6.1 to modulate chromatin accessibility of GSIS-coupling genes.
- A human BAF60a V278M variant reduces GSIS; knock-in mice recapitulate β-cell dysfunction and dysglycaemia.
- BAF60a deficiency reduces GLP-1R/GIPR expression, attenuating GLP-1R agonist insulinotropic effects.
Methodological Strengths
- Multi-species validation (mouse, nonhuman primate, human islets) with convergent evidence.
- Genetic causality supported by human variant identification and knock-in mouse modeling.
Limitations
- Therapeutic modulation of BAF60a was preclinical; no interventional human data.
- Extent to which findings generalize across diverse T2D etiologies and treatments remains to be defined.
Future Directions: Evaluate BAF60a as a predictive biomarker for incretin therapy and explore pharmacologic or epigenetic interventions to upregulate BAF60a/Nkx6.1 axis in β cells.
Impaired glucose-stimulated insulin secretion (GSIS) is a hallmark of β cell dysfunction in diabetes. Epigenetic mechanisms govern cellular glucose sensing and GSIS by β cells, but they remain incompletely defined. Here, we found that BAF60a functions as a chromatin regulator that sustains biphasic GSIS and preserves β cell function under metabolic stress conditions. BAF60a was downregulated in β cells from obese and diabetic mice, monkeys, and humans. β cell-specific inactivation of BAF60a in adult mice impaired GSIS, leading to hyperglycemia and glucose intolerance. Conversely, restoring BAF60a expression improved β cell function and systemic glucose homeostasis. Mechanistically, BAF60a physically interacted with Nkx6.1 to selectively modulate chromatin accessibility and transcriptional activity of target genes critical for GSIS coupling in islet β cells. A BAF60a V278M mutation associated with decreased β cell GSIS function was identified in human donors. Mice carrying this mutation, which disrupted the interaction between BAF60a and Nkx6.1, displayed β cell dysfunction and impaired glucose homeostasis. In addition, GLP-1R and GIPR expression was significantly reduced in BAF60a-deficient islets, attenuating the insulinotropic effect of GLP-1R agonists. Together, these findings support a role for BAF60a as a component of the epigenetic machinery that shapes the chromatin landscape in β cells critical for glucose sensing and insulin secretion.
2. Efficacy and safety of once-weekly basal insulin therapy in people with type 1 diabetes: A systematic review and meta-analysis.
Across five RCTs (n=1629), once-weekly basal insulin achieved HbA1c, weight, and time-in-range outcomes comparable to once-daily analogues but significantly increased level 3 hypoglycaemia. Weekly regimens needed less total bolus insulin, indicating altered basal–bolus dynamics.
Impact: This is the first meta-analysis focused exclusively on type 1 diabetes, directly informing regulatory, guideline, and adoption decisions for weekly basal insulins by quantifying a severe hypoglycaemia safety signal.
Clinical Implications: Weekly basal insulin may not be broadly safer in T1D despite HbA1c equivalence; clinicians should weigh convenience against elevated severe hypoglycaemia risk and consider patient selection, education, and CGM-linked safeguards.
Key Findings
- HbA1c, body weight, time-in-range and time-above-range were similar between weekly and daily basal insulin arms (high to moderate certainty).
- Level 3 hypoglycaemia occurred more frequently with once-weekly basal insulin (IRR 2.532, 95% CI 1.758–3.645).
- Weekly basal insulin reduced weekly bolus insulin dose (ETR 0.837, 95% CI 0.794–0.882).
Methodological Strengths
- Exclusive inclusion of T1D RCTs with predefined outcomes and certainty grading.
- Comprehensive multi-database search and independent triple-reviewer screening.
Limitations
- Heterogeneity in trial designs, algorithms, and adjunct technologies (e.g., CGM use) may influence hypoglycaemia rates.
- Long-term cardiovascular and microvascular outcomes were not assessed.
Future Directions: Define patient phenotypes and care pathways that maximize weekly insulin benefit while mitigating severe hypoglycaemia, including algorithm refinements and closed-loop integration.
AIMS: Once-weekly basal insulins may offer similar or superior HbA1c reduction compared to once-daily analogues in people with type 1 or type 2 diabetes. However, concerns about hypoglycaemia persist in individuals on multiple daily injections. This meta-analysis (PROSPERO CRD42024606874) aimed to evaluate the efficacy and safety of once-weekly basal insulin therapy in type 1 diabetes. MATERIALS AND METHODS: A systematic search was conducted in MEDLINE, Web of Science and CENTRAL up to 1 April 2025. We included randomized controlled trials (RCTs) comparing insulin icodec or efsitora against once-daily basal insulins in people with type 1 diabetes. Three reviewers independently evaluated the retrieved citations. The primary outcome was the change in HbA1c. Meta-analysis was performed using fixed- or random-effects models based on heterogeneity. RESULTS: Five RCTs were included, enrolling 1629 adults living with type 1 diabetes. Once-weekly and once-daily basal insulins had similar effects on HbA1c (high certainty), body weight (moderate certainty), time in range (moderate certainty) and time above range. However, safety concerns emerged due to increased rates of level 3 hypoglycaemia (incidence rate ratio 2.532, 95% confidence interval [CI] 1.758-3.645; moderate certainty). A significantly lower weekly bolus insulin dose was observed with once-weekly basal insulin therapy (estimated treatment ratio 0.837, 95% CI 0.794-0.882, I CONCLUSIONS: This meta-analysis is the first to evaluate the efficacy and safety of once-weekly basal insulin therapy exclusively in adults with type 1 diabetes and including all published RCTs. The analysis demonstrated a similar glucose-lowering effect compared to once-daily basal insulin but revealed an increased occurrence of severe hypoglycaemia.
3. Reevaluating the causal link between liver fat and hyperglycaemia.
Two-sample Mendelian randomization in 37,358 individuals found no causal effect of liver fat on fasting/postprandial glucose, HbA1c, fasting insulin, or HOMA-IR. Meta-analysis of 13 RCTs of steatosis-targeting drugs (n=2482) similarly showed no glycaemic improvements, challenging a direct causal model.
Impact: Combines genetic causal inference and RCT synthesis to overturn a prevalent assumption about hepatic steatosis driving hyperglycaemia, redirecting mechanistic and therapeutic focus in MASLD/MASH and diabetes.
Clinical Implications: Liver fat reduction alone may not lower glycaemia; treatment strategies should target pathways beyond steatosis (e.g., inflammation, hepatic insulin signaling, adipose-liver crosstalk). Outcome expectations from steatosis-directed drugs should be calibrated.
Key Findings
- MR showed no causal effect of liver fat on fasting glucose, HbA1c, postprandial glucose, fasting insulin, or HOMA-IR.
- Meta-analysis of 13 RCTs targeting hepatic steatosis found no significant improvements in fasting glucose or HbA1c versus controls.
- Meta-regression found no linear relationship between liver fat reduction and change in glycaemic indices.
Methodological Strengths
- Triangulation using MR with large GWAS and independent RCT meta-analysis.
- Consistent null findings across multiple glycaemic endpoints with sensitivity analyses.
Limitations
- MR assumes valid instruments and linearity; residual pleiotropy cannot be entirely excluded.
- RCTs varied in drug classes, duration, and populations; power to detect small glycaemic effects may be limited.
Future Directions: Probe non-steatosis mechanisms (inflammation, mitochondrial function, hepatokines) linking MASLD to dysglycaemia; design trials targeting these pathways with glycaemic endpoints.
AIMS: Given the proposed role of liver fat in diabetes, this study examined its potential causal relationship with glycaemic traits. MATERIALS AND METHODS: A two-sample Mendelian randomisation (MR) analysis using genome-wide association study (GWAS) data from 37 358 individuals was conducted to evaluate the causal effect of liver fat on fasting glucose level, HbA1c level, postprandial glucose level, fasting insulin level, and homeostatic model assessment of insulin resistance (HOMA-IR). A meta-analysis of randomised controlled trials (RCTs) examining drugs that target hepatic steatosis and their effects on glycaemic traits was subsequently performed. RESULTS: MR analysis revealed no causal effect of liver fat content on the following glycaemic traits: fasting glucose level (β = -0.006; p = 0.827), HbA1c level (β = -0.009; p = 0.366), postprandial glucose level (β = -0.063; p = 0.257), fasting insulin level (β = 0.010; p = 0.691), and HOMA-IR (β = 0.001; p = 0.965). In 13 RCTs of liver fat-targeted drugs (n = 2482), no significant differences were observed in the changes in fasting blood glucose (SMD: -0.09, 95% CI: -0.18 to 0.01) or HbA1c levels (SMD: -0.02, 95% CI: -0.12 to 0.07) between drug-treated patients and controls. Meta-regression analysis revealed no statistically significant linear relationship between liver fat reduction and changes in fasting blood glucose or HbA1c levels. CONCLUSION: The absence of a causal relationship between hepatic steatosis and glycaemic traits suggests that hyperglycaemia in metabolic dysfunction-associated steatotic liver disease may involve additional mechanisms beyond liver fat accumulation.