Are Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists Central Nervous System (CNS) Penetrant: A Narrative Review
Bibliographic record
Abstract
INTRODUCTION: Glucagon-like peptide-1 (GLP-1) is an incretin hormone that modulates glucose metabolism and insulin secretion. Recent translational and clinical research has evaluated the effects of GLP-1 receptor agonists (GLP-1 RAs), a class of drugs that mimic the action of native GLP-1 in the central nervous system (CNS). In addition to the efficacy of GLP-1 for the treatment of diabetes mellitus and obesity, preliminary evidence indicates GLP-1s have neuroprotective, therapeutic, and disease modification effects for select neurodegenerative disorders (e.g. Parkinson's disease, Alzheimer's disease). Among the available GLP-1 RAs, relatively few have been shown to be CNS penetrant. This article synthesizes extant literature reporting on CNS penetrants of GLP-1 RAs as proxied by brain imaging studies. Where available, studies that reported on the bioavailability of GLP-1 RAs in the CNS were identified. METHODS: A comprehensive search of PubMed, Ovid, and Web of Science from database inception to July 2024 was conducted. Inclusion criteria were English language publications with no date restrictions, preclinical and clinical studies with participants aged 18-80 and studies which focused on GLP-1 RAs including: "Semaglutide" or "Ozempic" or "Rybelsus" or "Wegovy" or "Dulaglutide" or "Trulicity" or "Exenatide" or "Byetta" or "Bydureon" or "Liraglutide" or "Lixisenatide" or "Tirzepatide" or "Mounjaro" or "Zepbound" or "Bydureon BCise" or "Adlyxin" or "Victoza" or "Saxenda". RESULTS: We identified 14 studies that were included in this synthesis. Preclinical studies suggest that select GLP-1 RAs cross the blood-brain barrier (BBB) (i.e. liraglutide, semaglutide, and exenatide). Replicated evidence suggests that CNS penetration of GLP-1 RAs can be proxied by reported effects of GLP-1 RAs on brain connectivity in human participants. CONCLUSION: Preclinical studies indicate that select GLP-1 RAs are CNS penetrant; whether GLP-1 RAs reproducibly engage neural targets hypothesized to subserve dimensions of psychopathology (e.g., general cognitive functions) remains incompletely characterized.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.003 | 0.002 |
| Bibliometrics | 0.008 | 0.010 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".