Daily Endocrinology Research Analysis
Analyzed 47 papers and selected 3 impactful papers.
Summary
Analyzed 47 papers and selected 3 impactful articles.
Selected Articles
1. Once-weekly Somapacitan in Children with Noonan Syndrome: Randomised Controlled Phase 3 Trial.
In a multinational phase 3 randomized sub-study (n=77), once-weekly somapacitan achieved higher annualized height velocity (10.4 vs 9.2 cm/year; ETD 1.2, 95% CI 0.32–2.03; p<0.01) and greater height SDS gain versus daily GH over 52 weeks, with similar tolerability. These data confirm noninferiority and demonstrate superiority of somapacitan in GH‑naïve children with Noonan syndrome.
Impact: This phase 3 RCT shows clinically meaningful superiority of a once-weekly GH formulation, potentially reducing treatment burden while improving growth outcomes in Noonan syndrome.
Clinical Implications: Consider once-weekly somapacitan as an efficacious alternative to daily GH for GH-naïve children with Noonan syndrome, with monitoring similar to standard GH therapy. Longer-term follow-up is needed to assess impact on near-adult height and cardiometabolic safety.
Key Findings
- Annualized height velocity at week 52 was higher with somapacitan vs daily GH (10.4 vs 9.2 cm/year; ETD 1.2, 95% CI 0.32–2.03; p<0.01).
- Height SDS increased more with somapacitan (ΔSDS 1.07) vs daily GH (ΔSDS 0.75); ETD 0.32 (95% CI 0.16–0.48).
- Somapacitan demonstrated noninferiority and superiority with a safety/tolerability profile similar to daily GH over 52 weeks.
Methodological Strengths
- Multinational, multicenter randomized active-comparator phase 3 design with prespecified primary endpoint.
- Direct head-to-head comparison of once-weekly vs daily GH dosing in GH-naïve Noonan syndrome.
Limitations
- Open-label design may introduce performance or assessment bias.
- 52-week main phase does not establish effects on near-adult height or long-term safety.
Future Directions: Evaluate long-term outcomes (near-adult height, cardiometabolic safety), real-world adherence/quality of life, and dosing optimization across Noonan phenotypes.
OBJECTIVE: Daily growth hormone (GH) injections are indicated for the treatment of short stature in children with Noonan syndrome, which presents a treatment burden for the child and their parents/caregivers. Somapacitan is a long-acting, reversible albumin-binding GH, developed for once-weekly administration. The objective of this study is to evaluate efficacy, safety and tolerability of somapacitan versus daily GH in children living with Noonan syndrome. DESIGN: REAL8 (NCT05330325) is a multi-national, multi-centre, randomised, open-labelled, active comparator, phase 3 basket study including four non-GH deficiency indications comprising a 52-week main phase and 104-week extension. Here, we present 52-week results from the REAL8Noonan syndrome sub-study. METHODS: Seventy-seven GH-treatment-naïve, prepubertal boys (aged 2.5 to 11 years) and girls (aged 2.5 to 10 years) with Noonan syndrome were randomized 2:1 to somapacitan 0.24 mg/kg/week or daily GH 0.050 mg/kg/day, administered subcutaneously. RESULTS: The primary endpoint, estimated mean annualized height velocity at week 52, was 10.4 cm/year for somapacitan versus 9.2 cm/year for daily GH (estimated treatment difference [ETD]: 1.2, 95% CI [0.32; 2.03]), confirming non-inferiority and demonstrating superiority of somapacitan compared to daily GH (p<0.01). The estimated change from baseline to week 52 in height standard deviation score was 1.07 and 0.75 for somapacitan and daily GH, respectively (ETD: 0.32, 95% CI [0.16; 0.48]). Somapacitan was well tolerated and had a similar safety profile to daily GH. CONCLUSION: Once-weekly somapacitan was confirmed as non-inferior and demonstrated superiority to daily GH in HV after 52 weeks of treatment in treatment-naïve children living with Noonan syndrome. Similar safety profiles and tolerability were observed for both groups.
2. Semaglutide Reduces Murine Blood Pressure Through the Vascular Smooth Muscle GLP-1 Receptor.
Using cell type–specific GLP-1R knockout mice, the authors show that vascular smooth muscle GLP-1Rs are required for semaglutide to lower blood pressure, whereas endothelial/immune GLP-1Rs are not. VSMC GLP-1Rs also mediate increases in GFR and natriuresis and are necessary for renal artery/kidney proteomic remodeling; semaglutide directly relaxes resistance arteries ex vivo.
Impact: Identifying VSMCs as the key GLP-1R–expressing cell type for BP lowering disentangles weight/endothelial effects and refines our mechanistic understanding of GLP‑1RA cardio-renal benefits.
Clinical Implications: Findings suggest GLP‑1RAs can lower BP via direct vascular actions independent of weight loss, supporting their use in patients with diabetes/obesity and hypertension. Human validation is needed to quantify effect size and interaction with standard antihypertensives.
Key Findings
- VSMC GLP-1Rs are essential for semaglutide-mediated BP reduction; Tie2+ endothelial/immune GLP-1Rs are not required.
- VSMC GLP-1Rs are required for semaglutide-induced increases in GFR and natriuresis.
- Semaglutide induces proteomic remodeling in renal artery/kidney that is abolished without VSMC GLP-1Rs.
- Semaglutide directly causes vasorelaxation in preconstricted mesenteric arteries ex vivo.
Methodological Strengths
- Cell type–specific GLP-1R knockout models enabling causal inference.
- Convergent evidence from in vivo hemodynamics, ex vivo vascular reactivity, and renal/arterial proteomics.
Limitations
- Findings derived from murine models; human vascular validation is lacking.
- Dose/exposure in mice may not match clinical pharmacokinetics.
Future Directions: Translate to humans with vascular imaging/physiology studies, assess BP response predictors, and explore synergy with renin–angiotensin or natriuretic therapies.
GLP-1 receptor (GLP-1R) agonists decrease blood glucose and body weight and reduce rates of cardiovascular and renal disease. Although GLP-1R activation lowers blood pressure (BP), the underlying mechanisms remain incompletely understood and have been attributed to weight loss and endothelial cell GLP-1R signaling. Here, we show that GLP-1Rs in vascular smooth muscle cells (VSMCs) are essential for semaglutide-mediated BP reduction in mice. In contrast, GLP-1Rs in Tie2+ endothelial or immune cells are not required for semaglutide to lower BP. The VSMC GLP-1R is dispensable for the effects of semaglutide on food intake, body weight, and blood glucose, but is required for its actions to increase glomerular filtration rate and promote natriuresis. Systemic semaglutide administration resulted in proteomic changes in the renal artery and kidney in pathways related to platelet aggregation, fibrin clot formation, lipid metabolism, and pro-apoptotic signaling that are abolished in mice lacking VSMC GLP-1R expression. Moreover, semaglutide directly induced vasorelaxation in pre-constricted mesenteric arteries ex vivo. Together, these findings identify VSMCs as a key cellular target linking GLP-1R activation to BP regulation, renal electrolyte excretion, and proteomic changes in renal artery and kidney.
3. Branched-chain α-keto acids impair glucose-stimulated insulin secretion in pancreatic β-cells under diabetes by reactivating the LDHA-lactate axis.
Across human and mouse islets and β-cells, BCKAs suppress GSIS and divert glucose flux from the TCA cycle toward LDHA‑mediated lactate production by directly binding/activating LDHA. Circulating BCKAs inversely correlate with insulin secretory capacity in humans, and lowering BCKAs improves glucose tolerance and GSIS in diabetic mice; β‑cell LDHA ablation rescues BCKA‑induced dysfunction.
Impact: This work reveals a previously unrecognized mechanism linking BCAA dysmetabolism to β-cell failure through LDHA reactivation, highlighting actionable metabolic nodes (BCKA, LDHA) for therapeutic targeting and biomarker development.
Clinical Implications: Suggests BCKAs as candidate biomarkers of β-cell secretory dysfunction and supports therapeutic strategies to reduce BCKAs or modulate LDHA activity in type 2 diabetes. Nutritional guidance regarding BCAA/BCKA load may merit investigation.
Key Findings
- BCKAs inhibit GSIS and glucose flux in human islets, mouse islets, and β-cell lines.
- Circulating BCKAs inversely correlate with insulin secretory capacity in diabetic humans.
- Reducing BCKAs improves glucose tolerance and GSIS in diabetic mice; impaired BCKA catabolism worsens GSIS.
- BCKAs bind LDHA, promote dimerization and activity, redirecting glucose to lactate; β-cell LDHA ablation restores GSIS despite BCKA exposure.
Methodological Strengths
- Cross-species validation including human islets, mouse islets, and in vivo models.
- Mechanistic depth with biochemical binding assays, metabolic flux, and β-cell–specific genetic manipulation.
Limitations
- Translational relevance requires clinical interventional studies targeting BCKAs/LDHA.
- Potential sex differences and long-term metabolic consequences need further evaluation.
Future Directions: Prospective human studies to validate BCKAs as biomarkers and test dietary/pharmacologic BCKA lowering or LDHA modulation on β-cell function and glycemic outcomes.
Dysmetabolism of branched-chain amino acid (BCAA) causes insulin resistance in type 2 diabetes, yet its effect on insulin-producing β-cells remains unclear. Here, we demonstrate that branched-chain α-ketoacids (BCKAs), derived from BCAAs, inhibited glucose-stimulated insulin secretion (GSIS) and glucose fluxes across human islets, mouse islets, and mouse β-cells. In diabetic humans, elevated circulating BCKAs negatively correlated with insulin secretory ability. Treatment with BCKA or its impaired catabolism suppressed GSIS in human islets and male mice, while reducing BCKA improved glucose tolerance and GSIS in male and female diabetic mice. Mechanistically, BCKA redirected glucose metabolism from the TCA cycle to the "β-cell disallowed" lactate dehydrogenase A (LDHA)-lactate axis. BCKA directly bound to LDHA, promoting its dimerization and enhancing enzymatic activity. β-cell-specific LDHA ablation restored GSIS and glucose tolerance in BCKA-fed male mice. Our findings demonstrate that BCKA disrupts insulin secretion through LDHA reactivation, linking aberrant BCAA metabolism to β-cell dysfunction in diabetes.