Daily Endocrinology Research Analysis
Analyzed 29 papers and selected 3 impactful papers.
Summary
Analyzed 29 papers and selected 3 impactful articles.
Selected Articles
1. Short- and Long-term Effects of Semaglutide 2.4 mg on Energy Intake, Appetite, and Food Reward: A 60-week, Double-Blind Randomized Controlled Trial.
In a 60-week double-blind RCT of 120 adults with overweight/obesity, semaglutide 2.4 mg consistently reduced ad libitum energy intake versus placebo at weeks 20, 40, and 60 (~238–295 kcal less). Subjective appetite benefits peaked at week 20 and were not significantly different by weeks 40/60, yet reduced responsiveness to food persisted, supporting energy-intake reduction as a primary mechanism of weight loss and maintenance.
Impact: This long-duration, registered, double-blind RCT isolates sustained caloric intake reduction as a mechanism for semaglutide’s weight-loss maintenance, informing both clinical expectations and mechanistic models.
Clinical Implications: Clinicians can counsel patients that semaglutide maintains reduced caloric intake beyond 6–12 months despite waning subjective appetite changes; tracking intake and food responsiveness may better guide maintenance strategies than relying on perceived hunger.
Key Findings
- Semaglutide reduced ad libitum energy intake versus placebo at weeks 20, 40, and 60 by ~295, ~250, and ~238 kcal, respectively.
- Appetite suppression and reductions in hunger/food preoccupation were larger at week 20, with no significant between-group differences at weeks 40 or 60.
- Responsiveness to food (Power of Food Scale) decreased more with semaglutide at weeks 20 and 40, supporting sustained behavioral mechanisms.
Methodological Strengths
- Randomized, double-blind, 60-week design with registered protocol (NCT05548647).
- Objective laboratory assessments of ad libitum energy intake with prespecified ANCOVA and jump-to-reference multiple imputation.
Limitations
- Laboratory-based intake tests may limit generalizability to free-living conditions.
- Modest sample size (n=120) limits subgroup analyses and detection of small effects at later timepoints.
Future Directions: Examine real-world energy intake with digital food logs and ecological momentary assessment, assess dose–response and combination with behavioral strategies, and link intake changes to long-term cardiometabolic outcomes.
BACKGROUND: Studies of up to 20 weeks have demonstrated reductions in energy intake, appetite, and food reward with semaglutide that may drive initial weight loss. These brief studies could not assess whether semaglutide has long-term effects on eating that support the maintenance of lost weight. OBJECTIVE: The goal of the present study was to compare short- and long-term energy intake, appetite, and food reward with semaglutide 2.4 mg to placebo. METHODS: This 60-week, double-blind trial randomized 120 adults with overweight/obesity in a 3:2 ratio to semaglutide 2.4 mg or placebo. In laboratory assessments at weeks 0, 20, 40, and 60, participants rated appetite when fasting and for 4-hours after a standardized breakfast. Energy intake was measured during an ad libitum lunch. Measures of food reward included the Power of Food Scale. Missing data were estimated using jump-to-reference multiple imputation, and ANCOVAs compared the groups in change at each assessment, controlling for baseline. RESULTS: The semaglutide group had significantly larger reductions from baseline in ad libitum energy intake relative to placebo at weeks 20, 40, and 60, consuming a mean ± SE of 294.6±64.0, 250.1±94.4, and 238.3±92.5 kcal less, respectively. At week 20, semaglutide-treated participants had significantly greater increases from baseline in appetite suppression following the standardized breakfast (MD=2197±823) and greater reductions in past-week hunger (MD=-17.4±4.8) and food preoccupation (MD=-14.9±4.5). However, the groups did not differ significantly in appetite outcomes at weeks 40 or 60. The semaglutide group had greater reductions in responsiveness to food at weeks 20 and 40 (MD=-0.4±0.2 and -0.6±0.2, respectively). CONCLUSIONS: In conclusion, semaglutide 2.4 mg continued to help participants consume fewer calories at 20, 40, and 60 weeks of treatment even though some subjective benefits declined. These findings suggest that reduced energy intake is a central mechanism by which semaglutide both induces and maintains weight loss. CLINICALTRIALS GOV NUMBER: NCT05548647, https://clinicaltrials.gov/study/NCT05548647.
2. Skeletal muscle-specific deficiency of Rab geranylgeranyl transferase beta subunit induces myopathy and exacerbates the symptoms caused by HMG-CoA reductase deficiency in mice.
Using inducible, muscle-specific knockout mice, the study shows HMGCR deficiency causes myopathy primarily via GGPP depletion, with early mitochondrial dysfunction preceding clinical signs; geranylgeraniol rescues fiber-type changes. Loss of RabGGT-β worsens and accelerates myopathy, implicating impaired protein geranylgeranylation as a key downstream driver.
Impact: Clarifies in vivo mechanisms of statin-associated myopathy, identifying GGPP depletion and impaired RabGGT-β–mediated prenylation as causal, with rescue by geranylgeraniol—highlighting actionable nodes within the mevalonate pathway.
Clinical Implications: Findings support mechanistic counseling for statin intolerance and motivate trials of pathway-modulating strategies (e.g., isoprenoid repletion, alternative lipid-lowering regimens) while monitoring for mitochondrial dysfunction.
Key Findings
- Hmgcr muscle knockout causes pronounced myopathy with early loss of oxidative MyHC I/IIa fibers, later affecting glycolytic IIb fibers; changes are reversible with geranylgeraniol.
- Rabggtb knockout alone induces later-onset myopathy; combined Hmgcr/Rabggtb knockout dramatically accelerates and exacerbates disease.
- Mitochondrial dysfunction appears early across models, preceding clinical signs, consistent with causality driven by GGPP depletion and impaired geranylgeranylation.
Methodological Strengths
- Multiple inducible, muscle-specific genetic knockouts with complementary phenotyping and biochemical validation.
- Rescue experiments with geranylgeraniol and confirmation of prenylation deficits via subcellular fractionation.
Limitations
- Preclinical mouse models limit direct generalizability to humans and to diverse statin doses/exposures.
- Exact animal sample sizes per experiment are not detailed in the abstract.
Future Directions: Translate to human studies by assessing prenylation biomarkers and mitochondrial function in statin-intolerant patients; test isoprenoid repletion or alternative lipid-lowering strategies in early-phase trials.
OBJECTIVE: Statins (HMG-CoA reductase inhibitors) are associated with myopathy, yet the precise in vivo mechanisms underlying this association remain unclear. Emerging evidence implicates a deficiency of geranylgeranyl pyrophosphate (GGPP), a key downstream isoprenoid metabolite of the mevalonate pathway. We employed novel muscle-specific genetic mouse models to elucidate the roles of GGPP and Rab geranylgeranyl transferase β (RabGGT-β) in the development of myopathy. METHODS: Using doxycycline-inducible Cre-LoxP technology, we generated three skeletal muscle-specific knockout (KO) models: Hmgcr-DimKO, Rabggtb-DimKO, and combined Hmgcr/Rabggtb-DimKO mice. The severity of myopathy was evaluated based on serum creatine kinase levels and histological examination. Mitochondrial mass and function were rigorously quantified. Prenylation deficit in Rabggtb-DimKO mice was confirmed via subcellular fractionation. To validate GGPP's involvement, rescue experiments were conducted using its precursor, geranylgeraniol (GGOH). RESULTS: Hmgcr KO resulted in pronounced myopathy, marked by an early reduction in mitochondria-rich myosin heavy chain (MyHC) type I and IIa muscle fibers, followed by a later reduction in mitochondria-poor glycolytic MyHC type IIb muscle fibers, and these changes were reversed by GGOH administration. Rabggtb-DimKO mice developed myopathy later than Hmgcr-DimKO mice; however, in Hmgcr/Rabggtb-DimKO mice, myopathy was dramatically accelerated and more severe. Across all models, mitochondrial dysfunction emerged early-preceding clinical signs of myopathy-consistent with a causal relationship. CONCLUSION: Our findings demonstrate that myopathy induced by HMGCR deficiency is primarily driven by GGPP depletion in a mouse model. Furthermore, impaired RabGGT-β-mediated protein geranylgeranylation represents a critical downstream mechanism that aggravates the myopathic phenotype. Early mitochondrial abnormalities may contribute to the pathogenesis of myopathy due to disruption of the mevalonate pathway.
3. Integrated proteomic and metabolomic analyses implicate redox-metabolic pathways in PTSD-associated multisystem disease and accelerated aging.
In 393 trauma-exposed individuals, integrated plasma proteomics and metabolomics identified 114 proteins and 7 metabolites differentiating PTSD, converging on redox and amino acid metabolism linked to synaptic and oxidative stress pathways. Proteomic aging signatures indicated accelerated aging at the pancreatic, lung, and organismal levels in PTSD.
Impact: Links PTSD to multisystem accelerated aging through coordinated redox–metabolic alterations, prioritizing biomarkers (e.g., GDF15, cystathionine) and organ targets for risk stratification and mechanistic intervention.
Clinical Implications: Biomarker panels capturing redox–metabolic stress (e.g., GDF15, amino acid/redox metabolites) could aid in risk stratification and monitoring; organ-specific aging signals (pancreas, lung) may inform targeted screening in PTSD populations.
Key Findings
- Identified 114 differentially expressed proteins and 7 metabolites in PTSD versus trauma-exposed controls.
- Top signals included NCAN, BCAN, NCAM1, GDF15 (proteins) and serotonin, lactate, glutamic acid, cystathionine (metabolites).
- Proteomic organ aging analyses showed accelerated aging in pancreas, lung, and at the organismal level in PTSD.
- Integrative correlations linked redox/amino acid metabolites to synaptic and oxidative stress-related proteins.
Methodological Strengths
- Large-scale plasma proteomics (9404 proteins) with targeted metabolomics (145 metabolites) in a well-characterized cohort.
- Integrative multi-omics and organ aging analyses enhancing biological inference beyond single-omic approaches.
Limitations
- Cross-sectional design limits causal inference between redox–metabolic changes and aging outcomes.
- Generalizability may be constrained to trauma-exposed populations; residual confounding is possible.
Future Directions: Prospective validation of biomarker panels, mechanistic probing of redox pathways, and interventional studies targeting metabolic stress to mitigate organ-specific accelerated aging in PTSD.
Posttraumatic stress disorder (PTSD) is associated with increased risk of chronic disease and premature aging, yet underlying molecular mechanisms remain unclear. We performed plasma proteomics (SomaScan; 9404 proteins) and targeted metabolomics (145 metabolites) in 393 World Trade Center responders (232 with PTSD, 161 trauma-exposed controls). A total of 114 proteins and seven metabolites were differentially expressed in PTSD. Top proteins included NCAN, BCAN, NCAM1, and GDF15. Top metabolites included serotonin, lactate, glutamic acid, and cystathionine. Integrative analyses showed coordinated proteomic-metabolomic alterations, with widespread correlations linking metabolites involved in redox and amino acid metabolism to synaptic and oxidative stress-related proteins. Gene ontology enrichment identified neuronal plasticity, immune activation, extracellular matrix remodeling, and oxidative stress. Proteomic organ aging analyses revealed accelerated aging in the pancreas, lung, and at the organismal level in PTSD. These results reveal a redox-metabolic mechanism through which PTSD may drive multisystem aging and elevate disease risk.