Animal only
This systematic review (PRISMA-guided) examined whether GLP-1 receptor agonists (GLP-1 RAs) exert neuroprotective effects in preclinical models of stroke and Parkinson's disease (PD). Researchers searched four major databases (Cochrane CENTRAL, PubMed, Web of Science, Scopus), identifying 1,643 records and ultimately including 13 experimental animal studies published between 2013 and 2026. For stroke, studies primarily used middle cerebral artery occlusion (MCAO) models; the review found that agents such as liraglutide and linagliptin were associated with notable reductions in infarct volume and improved neurological deficit scores in treated animals. For PD models, the included studies reported improvements in motor function, preservation of dopaminergic neurons, and reduced α-synuclein aggregation. Across both disease models, GLP-1 RAs appeared to modulate neuroinflammatory markers (TNF-α, IL-1β, IL-6), oxidative stress indicators (ROS, 4-HNE), and apoptotic pathways (increased Bcl-2, decreased Bax). Risk of bias assessment using the SYRCLE tool rated overall quality as moderate, with four studies flagged as high risk due to small sample sizes and inadequate reporting of randomization and blinding procedures. The authors concluded that while preclinical evidence appears promising, standardized studies and clinical trials are needed before translational conclusions can be drawn.
Disease-a-month : DM · Jun 2026DOI ↗ Animal only
This study developed a targeted nanodelivery system — GLP-1@tMSN (glucagon-like peptide-1 loaded into matrix metalloproteinase-2-targeted mesoporous silica nanoparticles) — designed to mobilize endothelial progenitor cells (EPCs) and promote re-endothelialization following coil embolization of intracranial aneurysms (IAs). Using a rat coiled aneurysm model, the researchers evaluated whether the platform could recruit EPCs to the lesion site and accelerate vascular repair. The study found that GLP-1@tMSN significantly enhanced EPC recruitment and re-endothelialization compared to controls. After 28 days, histological analysis showed formation of mature endothelial-like tissue in treated animals, while controls exhibited fibrous tissue. Immunofluorescence confirmed preferential accumulation of CD34+VEGFR2+ EPCs at the lesion site, alongside activation of the Wnt/β-catenin signaling pathway, which the authors implicate as a key driver of vascular repair. Preliminary biocompatibility assessments suggested an acceptable safety profile. Limitations include the exclusive use of a rat model, a single 28-day follow-up endpoint, small experimental scale, and lack of human translational data. The authors conclude that this nanotherapeutic approach may hold promise for reducing long-term IA recurrence after embolization, though clinical validation is needed.
Journal of neurosurgery · Jun 2026DOI ↗ Animal only
This study investigated whether sustained GLP-1 gene delivery could stimulate β-cell regeneration in diabetic rats, and whether regenerative responses differ between neonatal and adult stages. Researchers engineered a third-generation HIV-based lentiviral vector encoding native GLP-1 (LentiGLP-1) under a CMV promoter. Two rat models of type 2 diabetes were used: neonatal rats treated with low-dose streptozotocin (STZ) to exploit developmental pancreatic plasticity, and adult rats subjected to a high-fat diet combined with low-dose STZ. In neonatal diabetic rats, LentiGLP-1 administration markedly promoted differentiation of ductal and progenitor cells into insulin-producing β-cells, accompanied by increased β-cell proliferation. In adult diabetic rats, LentiGLP-1 partially restored β-cell populations via activation of residual progenitors and stimulation of existing β-cell replication, with improvements in glycemic control and insulin sensitivity. Acinar cells were not observed to contribute to β-cell regeneration in either model. A key limitation is that findings are entirely in rodents, and the translational relevance to human β-cell biology remains unestablished. The study provides mechanistic insight into developmentally regulated GLP-1 effects but does not constitute evidence of efficacy in humans.
Journal of molecular medicine (Berlin, Germany) · Jun 2026DOI ↗ Animal only
This preclinical study designed and tested a novel unimolecular dual agonist that combines glucagon-like peptide-1 (GLP-1) and fibroblast growth factor-21 (FGF21) into a single molecule, connected by a thermally responsive elastin-like polypeptide linker intended to form a sustained-release subcutaneous depot. Receptor activity was first confirmed in cell-based assays. The molecule was then tested in male C57Bl/6J mice fed a diet designed to induce advanced metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis. The study found that treated mice showed improvements in body weight, liver mass, blood glucose, and cholesterol compared to controls. Histological and molecular analyses indicated reductions in liver fat accumulation, inflammation, and fibrosis, along with decreased expression of inflammatory and fibrotic marker genes and increased hepatocyte proliferation. Limitations include the exclusive use of a single male mouse strain, the absence of female animals, and the inherent translational gap between diet-induced rodent models and human MASH. No human data were generated. The authors conclude that this dual-agonist approach warrants further development as a potential chronic liver disease therapy.
Communications medicine · Jun 2026DOI ↗ Animal onlyPreprint
This mouse study investigated the effects of semaglutide, a GLP-1 receptor agonist (GLP-1 RA), administered from preconception through lactation in dams fed either a high-fat diet (HFD) or a standard diet. Researchers assessed metabolic outcomes in both the treated mothers and their offspring, who were weaned onto a standard diet. The study found that semaglutide improved body composition and glucose metabolism in HFD-fed dams during pregnancy, and these benefits persisted approximately 10 weeks after weaning even after treatment was discontinued. Offspring born to HFD-fed, untreated dams showed impaired glucose homeostasis and hepatic steatosis (fatty liver) at 18 weeks of age. These metabolic disturbances were attenuated in offspring whose mothers received semaglutide. Notably, semaglutide treatment did not adversely affect conception rates or fetal viability. The authors conclude that GLP-1 RA therapy during the perinatal period may improve both maternal and offspring metabolic health in an obesity mouse model, and they call for further investigation into GLP-1–based therapies in this context. Key limitations include the exclusive use of a mouse model, limiting direct translation to human pregnancy, and the fact that this appears to be a preprint not yet formally peer-reviewed.
Unknown journal · Jun 2026DOI ↗ Animal only
This mouse study investigated the molecular mechanisms by which tirzepatide (TZP), a dual GIP/GLP-1 receptor agonist, affects the liver in metabolic dysfunction-associated steatotic liver disease (MASLD). Male C57BL/6J mice (n=32) were fed a high-fat, high-fructose (HFHFr) diet to induce MASLD and then randomized to receive no treatment, semaglutide (Sema), or TZP. Researchers combined RNA sequencing and liquid chromatography-mass spectrometry (LC-MS) to generate hepatic transcriptomic and proteomic profiles, with key targets validated by PCR and immunoblotting. The study found that HFHFr feeding produced hyperglycemia, insulin resistance, elevated liver enzymes, and hepatic steatosis and inflammation. Both TZP and Sema were associated with improvements in these parameters; TZP was associated with reductions in pro-inflammatory markers (MCP-1, IL-1β, TNF-α, GSDMD) and partial restoration of IL-10. Integrated omics analysis implicated the CCL2/CCR2 chemokine axis and PI3K-AKT signaling pathway as key molecular signatures associated with TZP's hepatic effects. Key limitations include the exclusive use of an animal model, a small sample size, and the mechanistic (non-causal) nature of omics associations.
BMC gastroenterology · Jun 2026DOI ↗ Animal only
This preclinical study investigated whether obesity could be reversed without activating the GLP-1 receptor (GLP-1R), which is commonly associated with adverse gastrointestinal side effects in current therapies. Using diet-induced obese (DIO) mice and rats, as well as GLP-1R knock-out (KO) mice, researchers tested selective, dual, and triple agonists targeting the GIP receptor (GIPR), glucagon receptor (GCGR), and GLP-1R in various combinations. Three independent experimental approaches — (1) administering the triagonist retatrutide to GLP-1R KO mice, (2) physically combining separate selective GIPR and GCGR agonists, and (3) testing a novel unimolecular GIPR:GCGR co-agonist called BWB3054 — all demonstrated meaningful reductions in body weight and improvements in blood glucose without meaningful GLP-1R engagement. BWB3054 showed potency at the mouse GIPR comparable to retatrutide, 4-fold reduced potency at the mouse GCGR, and more than 100-fold reduced potency at the mouse GLP-1R. Indirect calorimetry and pair-feeding studies were used to characterize mechanisms of weight loss. A key limitation is that all experiments were conducted in rodents, leaving the translatability of these findings to humans uncertain. The study raises the possibility that GLP-1R-independent obesity treatment strategies could avoid the GI tolerability issues seen with current agents.
Molecular metabolism · Apr 2026DOI ↗ Animal only
This animal study compared the anti-atherosclerotic effects of tirzepatide (a dual GIP/GLP-1 receptor agonist) and semaglutide (a selective GLP-1 receptor agonist) in ApoE knockout mice. Mice were treated with streptozotocin to induce diabetes and divided into early diabetes, late diabetes, and non-diabetic groups, each receiving either agent or saline for 12 weeks. The study found that in the early diabetes group, both tirzepatide and semaglutide significantly reduced aortic plaque formation compared to controls, with modest improvements in blood glucose and lipid levels. No significant vascular effects were observed in the late diabetes or non-diabetic groups in terms of plaque reduction. Tirzepatide more broadly reduced inflammatory markers—including Mcp-1, Il-6, I-cam, and Cd68—compared to semaglutide. Anti-inflammatory effects were also detected in non-diabetic mice, suggesting possible vascular protective mechanisms independent of metabolic control. The authors conclude that dual incretin receptor agonism may offer cardiovascular benefits, though the specific contribution of GIP signaling requires further investigation. Key limitations include the use of an animal model, which may not translate directly to human cardiovascular disease.
Scientific reports · Apr 2026DOI ↗ Animal only
This animal study investigated the anti-obesity effects of three GLP-1 receptor agonist peptides — semaglutide, tirzepatide, and retatrutide — in melanocortin 4 receptor knockout (MC4R KO) mice, a model of genetically driven obesity caused by disruption of the POMC-MC4R signaling pathway. All three compounds were administered for 21 days, after which body weight, body composition, metabolic markers, liver health, and gene expression were assessed. The study found that all three GLP-1 analogs produced statistically significant reductions in body weight, with tirzepatide showing the greatest effect (approximately 31.6%), followed by retatrutide (approximately 24.1%) and semaglutide (approximately 19.7%). All three agents reduced both fat and lean mass, improved plasma insulin levels and insulin resistance (HOMA-IR), lowered cholesterol, and reduced markers of liver damage (AST and ALT) as well as liver hypertrophy. Gene expression analysis showed suppression of fatty acid synthesis genes, but no significant effect on inflammatory gene expression. Energy expenditure was reduced by all agents; only tirzepatide significantly decreased the respiratory quotient. A key limitation is that this is a mouse model study, and findings may not directly translate to humans. The authors suggest MC4R KO mice are a valid model for studying obesity-related drug efficacy.
International journal of obesity (2005) · Feb 2026DOI ↗ Animal only
This preclinical study examined how survodutide — a dual glucagon receptor (GCGR) and GLP-1 receptor (GLP-1R) agonist in clinical development for obesity and MASH — acts in the brain to reduce body weight. Researchers first mapped GCGR and GLP-1R expression in human and mouse circumventricular organs (CVOs), finding that GCGR is barely detectable in the area postrema (AP) and arcuate nucleus of the hypothalamus (ARH), whereas GLP-1R is expressed in both regions. Using a fluorophore-labeled version of survodutide in mice, the study found that the compound accesses CVOs and nearby hypothalamic and hindbrain nuclei directly, without evidence of broadly crossing the blood-brain barrier. C-Fos activation mapping showed that survodutide activated multiple brain nuclei associated with food intake control. A long-acting GCGR-selective agonist, by contrast, did not activate satiety-related brain regions or reduce food intake, though it did reduce body weight, suggesting the appetite-suppressing effects of survodutide are primarily GLP-1R dependent. Limitations include the exclusively preclinical (mouse) design and the use of a labeled surrogate compound. The authors conclude the findings support a dual mechanism for survodutide's weight-lowering effects.
Molecular metabolism · Feb 2026DOI ↗ Animal only
This study investigated whether milk-derived small extracellular vesicles (sEVs) could serve as oral delivery vehicles for two GLP-1 receptor agonists (GLP-1RAs): semaglutide and tirzepatide. Researchers loaded both peptides onto sEVs in vitro and administered them orally to diabetic db/db mice—a well-established mouse model of type 2 diabetes. The study found that both peptides were efficiently incorporated into the sEV carrier system and that oral administration of the loaded vesicles effectively reduced blood glucose levels in the diabetic mice. The authors compared this approach to the existing SNAC (sodium N-[8-(2-hydroxybenzoyl) amino] caprylate) technology used in the commercially approved oral semaglutide formulation (Rybelsus), arguing that sEVs offer broader applicability across multiple peptide drugs, not just semaglutide. Key limitations include the exclusive use of an animal model with no human pharmacokinetic or efficacy data, a relatively small and homogeneous study design, and the early-stage, preclinical nature of the platform. Translation to humans remains undemonstrated.
Journal of extracellular biology · Nov 2025DOI ↗ Animal only
This study describes the development and validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method for measuring tirzepatide — a dual GIP/GLP-1 receptor agonist — in rat plasma. Researchers used protein precipitation with methanol for sample preparation, a peptide C18 column for chromatographic separation, and positive electrospray ionization with multiple reaction monitoring for detection, using semaglutide as an internal standard. The method demonstrated good linearity (1–1000 ng/mL), with intra- and inter-day accuracy and precision meeting regulatory criteria. Stability under various storage and handling conditions was also confirmed. The validated method was then applied to a pharmacokinetic study in rats administered tirzepatide intravenously and subcutaneously at 0.3 mg/kg. The study reports terminal half-lives of approximately 10 hours via both routes and estimates subcutaneous bioavailability at roughly 62%. Key limitations include the exclusive use of a rat model, a single dose level, and a small number of animals typical of preclinical PK studies, meaning findings may not translate directly to humans. The authors suggest the method could be adapted for quantifying other structurally similar peptide therapeutics.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences · Oct 2025DOI ↗ Animal only
This preclinical study investigated whether three GLP-1-based receptor agonists — semaglutide (GLP-1 receptor agonist), tirzepatide (dual GLP-1/GIP receptor agonist), and retatrutide (triple GIP/GLP-1/glucagon receptor agonist) — could alter the interoceptive (subjective-like) effects of alcohol in rats. Using an operant drug discrimination paradigm in both male and female rats, researchers trained animals to distinguish alcohol from vehicle, then tested whether these compounds disrupted that learned discrimination. The study found that acute administration of all three agents attenuated alcohol's discriminative stimulus effects, suggesting modulation of how alcohol "feels" internally. Repeated semaglutide treatment maintained this effect over a 15-day period, and the effect reversed within three days of cessation. The authors suggest these findings may help explain clinically observed reductions in alcohol craving and drinking in humans receiving GLP-1 receptor agonists. Limitations include the exclusive use of animal models, meaning direct translation to human subjective alcohol experience remains uncertain, and the study does not assess long-term outcomes or dependence-related endpoints.
Psychopharmacology · Jul 2025DOI ↗ Animal only
This study investigated the mechanisms underlying weight loss produced by CagriSema — a combination of cagrilintide (an amylin analogue) and semaglutide (a GLP-1 analogue) — in a rat model. Researchers quantified the contributions of reduced energy intake versus preserved energy expenditure to overall weight loss. Rats treated with CagriSema achieved approximately 12% body weight loss alongside a 39% reduction in food intake. To isolate the role of energy intake, the authors used two comparison conditions: pair-feeding (matching food intake to CagriSema-treated animals) and weight matching (determining how much food restriction alone would be needed to achieve equivalent weight loss, which required a 51% reduction in intake). The gap between these conditions suggested that roughly one-third of CagriSema's weight loss effect was attributable to blunting of metabolic adaptation — the phenomenon where the body typically reduces energy expenditure in response to caloric restriction. Limitations include that findings are from an animal model and may not directly translate to humans, and the study does not address long-term outcomes. The authors conclude that CagriSema's dual action on both energy intake and expenditure may contribute to its potential effectiveness as an obesity treatment.
Nature metabolism · Jul 2025DOI ↗ Animal only
This preclinical study investigated whether mazdutide — a dual glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR) agonist — could improve cognition in a mouse model of type 2 diabetes mellitus (T2DM). Male db/db mice (a well-established T2DM model characterized by obesity and hyperglycemia) were treated with mazdutide and compared against dulaglutide, a GLP-1R-only agonist. Researchers assessed cognitive function via behavioral tests and examined brain pathology for neurodegenerative markers. They also applied transcriptomic, proteomic, and metabolomic (multi-omics) analyses to explore underlying molecular mechanisms. The study found that mazdutide-treated mice showed greater improvements in cognitive performance compared to dulaglutide-treated mice, along with better neuronal structure and brain tissue integrity. Multi-omics data implicated molecular pathways related to neuroprotection, energy metabolism, and synaptic plasticity as potential contributors to these effects. Key limitations include exclusive use of male mice, meaning results cannot be generalized to females, and the entirely preclinical nature of the study. No human data were collected, so whether these findings translate to people with T2DM remains unknown. The authors suggest mazdutide may warrant further investigation as a treatment for metabolic disorder-associated cognitive decline.
EBioMedicine · Jun 2025DOI ↗ Animal onlyPreprint
This preclinical study examined whether three incretin-based receptor agonists — semaglutide (GLP-1 receptor agonist), tirzepatide (dual GLP-1/GIP receptor agonist), and retatrutide (triple GIP/GLP-1/glucagon receptor agonist) — could alter the interoceptive (subjective) effects of alcohol in rats using an operant drug discrimination paradigm. Male and female rats were trained to discriminate alcohol from saline, then tested after acute or repeated drug administration. The study found that acute administration of all three compounds reduced alcohol's discriminative stimulus effects, suggesting each compound modulated how the animals internally perceived alcohol. Repeated semaglutide treatment sustained this effect across a 15-day period, though discrimination returned to baseline levels within three days of stopping treatment. The authors interpret these findings as potentially relevant to understanding why GLP-1 receptor agonists reduce drinking behavior in humans, hypothesizing that blunting alcohol's subjective effects may be a contributing mechanism. Key limitations include the exclusive use of an animal model, meaning translation to human subjective experience remains uncertain, and the study does not establish clinical efficacy or safety in people with alcohol use disorder.
Unknown journal · Apr 2025DOI ↗ Animal only
This paper describes the preclinical pharmacological profiling and biomarker-guided selection process used to identify survodutide (BI 456906) as a clinical development candidate from a library of 19 dual glucagon receptor (GCGR)/GLP-1R agonists. Researchers assessed receptor potency using cAMP assays in CHO-K1 cells expressing human GCGR and GLP-1R, as well as in insulinoma (MIN6) cells and rat primary hepatocytes for endogenous receptor activity. In vivo target engagement was evaluated in lean mice using oral glucose tolerance tests (GLP-1R biomarker) and plasma FGF21 and liver NNMT mRNA expression (GCGR biomarkers). Efficacy was further tested in diet-induced obese (DIO) mice for body weight reduction and in diabetic db/db mice for glucose lowering. A strong correlation was found between in vitro and in vivo GCGR and GLP-1R biomarkers, enabling candidate ranking. Survodutide demonstrated balanced dual agonism, producing greater body weight reduction than selective GLP-1R agonists while maintaining comparable antidiabetic effects. Key limitations include that all efficacy data are from rodent models, and human pharmacological profiling is not reported in this paper. Survodutide is now in Phase 3 clinical trials for obesity.
Diabetes, obesity & metabolism · Apr 2024DOI ↗ Animal only
This preclinical study investigated the neurological mechanisms by which obesity medications suppress food intake, focusing on proglucagon (PPG)-expressing neurons in the nucleus of the solitary tract (PPG-NTS). Using single-nucleus RNA sequencing and histochemistry, researchers characterized gene expression profiles of PPG-NTS neurons in rodents, finding that serotonin 2C receptors (5-HT2CR) — the target of lorcaserin — were widely expressed in these neurons, while GLP-1 receptors and melanocortin-4 receptors were not. Lorcaserin was found to significantly activate PPG-NTS neurons. When PPG-NTS neurons were virally ablated, lorcaserin lost its ability to suppress food intake, whereas the MC4R agonist melanotan-II retained its effect, confirming the functional role of 5-HT2CR expression in these neurons. Additionally, combining lorcaserin with GLP-1R agonists liraglutide or exendin-4 produced greater food intake reduction than either drug alone. The study concludes that PPG-NTS neurons are a necessary mechanistic link for lorcaserin's appetite-suppressing effects and suggests that combining 5-HT2CR and GLP-1R agonists may enhance therapeutic outcomes. Key limitations include that all experiments were conducted in animals, and translational relevance to humans remains to be established.
Molecular metabolism · Dec 2022DOI ↗