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The metabolic-brain axis: GLP-1 signaling, insulin resistance, and obesity pharmacotherapy in neurodegeneration
Maryline Santerre, Natalia Shcherbik, Bassel E Sawaya. Metabolism: clinical and experimental, 2026-10-30
Topic: Gut, metabolism and diet
The intersection of metabolic disease and neurodegeneration represents one of the most consequential frontiers in translational neuroscience. Converging epidemiological, mechanistic, and pharmacological evidence supports a bidirectional metabolic-brain axis in which systemic insulin resistance, obesity, and chronic metabolic inflammation are associated with and may contribute to alterations in neuronal survival, synaptic plasticity, and neuroimmune homeostasis. GLP-1 receptor agonists, originally developed for glycemic control and weight management, have therefore been investigated as potential disease-modifying therapies across Alzheimer's disease, Parkinson's disease, and related neurodegenerative conditions through mechanisms including neuronal PKA activation, microglial NLRP3 suppression, mitochondrial biogenesis, and restoration of AQP4 perivascular localization that may contribute to glymphatic waste clearance. Direct human evidence for these CNS mechanisms remains limited or absent, with current support derived primarily from preclinical models and indirect human data, as detailed in Table 1, warranting dedicated investigation in the context of GLP-1 receptor agonism. Importantly, the two pivotal phase 3 programs designed to test this hypothesis in humans - EVOKE/EVOKE+ in early Alzheimer's disease and Exenatide-PD3 in Parkinson's disease - have both now reported, and neither demonstrated a statistically significant benefit on its primary clinical endpoint, despite favorable biomarker and epidemiological signals preceding these results. This review synthesizes current knowledge on brain insulin signaling, GLP-1 neurobiology, obesity-driven neuroinflammation, and the translational evidence for metabolic therapeutics in neurodegeneration, and uses the dissociation between mechanistic plausibility, epidemiological association, and null confirmatory trial results to identify critical knowledge gaps and translational barriers related to CNS target engagement, optimal dosing, and disease-modifying efficacy of GLP-1 receptor agonists. The review is organized into four major themes: brain insulin signaling, central GLP-1 biology, obesity-associated neuroinflammation, and the translational evidence supporting metabolic therapies for neurodegenerative disease.
Key findings
- Converging epidemiological, mechanistic, and pharmacological evidence supports a bidirectional metabolic-brain axis in which systemic insulin resistance, obesity, and chronic metabolic inflammation are associated with and may contribute to alterations in neuronal survival, synaptic plasticity, and neuroimmune homeostasis.
- Importantly, the two pivotal phase 3 programs designed to test this hypothesis in humans - EVOKE/EVOKE+ in early Alzheimer's disease and Exenatide-PD3 in Parkinson's disease - have both now reported, and neither demonstrated a statistically significant benefit on its primary clinical endpoint, despite favorable biomarker and epidemiological signals preceding these results.
- This review synthesizes current knowledge on brain insulin signaling, GLP-1 neurobiology, obesity-driven neuroinflammation, and the translational evidence for metabolic therapeutics in neurodegeneration, and uses the dissociation between mechanistic plausibility, epidemiological association, and null confirmatory trial results to identify critical knowledge gaps and translational barriers related to CNS target engagement, optimal dosing, and disease-modifying efficacy of GLP-1 receptor agonists.
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Study details
- Study designclinical trial
- Evidence strengthLow
How this study scored 45/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record, multi-centre collaboration and free to read, so those were left out: it earned 25 of the 56 points we could judge it on, which is 45 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Metabolism: clinical and experimental) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | Design recorded as “clinical trial”, which our rubric does not rank (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 5 / 5 | 2026 — within 1 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 42962966) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 25 / 56 | Scored on 10 of 20 parts. We have no data for the rest, so they are left out: 25 of the 56 points we could judge it on is 45 out of 100. |
| Total | 45 / 100 | — |
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APA 7th
Santerre, M., Shcherbik, N., & Sawaya, B. E. (2026). The metabolic-brain axis: GLP-1 signaling, insulin resistance, and obesity pharmacotherapy in neurodegeneration. Metabolism: clinical and experimental. https://doi.org/10.1016/j.metabol.2026.156810
Vancouver
Santerre M, Shcherbik N, Sawaya BE. The metabolic-brain axis: GLP-1 signaling, insulin resistance, and obesity pharmacotherapy in neurodegeneration. Metabolism: clinical and experimental. 2026. doi:10.1016/j.metabol.2026.156810. PMID: 42962966.
BibTeX
@article{santerre2026-42962966,
author = {Santerre, Maryline and Shcherbik, Natalia and Sawaya, Bassel E},
title = {{The metabolic-brain axis: GLP-1 signaling, insulin resistance, and obesity pharmacotherapy in neurodegeneration}},
journal = {Metabolism: clinical and experimental},
year = {2026},
doi = {10.1016/j.metabol.2026.156810},
pmid = {42962966},
url = {https://doi.org/10.1016/j.metabol.2026.156810}
}