Intranasal long R3 insulin-like growth factor-1 treatment promotes amyloid plaque remodeling in cerebral cortex but fails to preserve cognitive function in male 5XFAD mice.
Intranasal LR3-IGF-1 treatment improved some aspects of amyloid plaque pathology in male 5XFAD mice but did not preserve cognitive function.
Where it sits
this study against the rest of the igf-1 lr3 (long r3 igf-1) corpusSummary and findings
This study investigated the effects of intranasal long R3 insulin-like growth factor-1 (LR3-IGF-1) on cognitive decline and amyloid pathology in male 5XFAD mice over 7 months. The treatment did not significantly alter cognitive symptoms but improved body composition and some aspects of amyloid plaque pathology. No therapeutic claims are made.
Abstract
<h4>Background</h4>Insulin-like growth factor-1 (IGF-1) promotes neurogenesis, cell survival, and glial function, making it a promising candidate therapy in Alzheimer's disease (AD).<h4>Objective</h4>Long arginine 3-IGF-1 (LR3-IGF-1) is a potent IGF-1 analogue. We sought to determine whether intranasal (IN) LR3 treatment would delay cognitive decline and pathology in 5XFAD mice.<h4>Methods</h4>Wildtype and 5XFAD male mice were treated for 7 months (3-10 months of age), with IN LR3-IGF-1 or IN Vehicle (Veh) (n = 19-27 mice/group). Behavior, memory, and brain imaging were assessed at 8-9 months of age and tissues collected at 10 months. A comprehensive amyloid-β (Aβ) profile and other pathologic features were conducted and supportive <i>in vitro</i> stimulation studies in BV-2 microglial cells were also performed.<h4>Results</h4>In male 5XFAD mice, IN LR3-IGF-1 treatment improved body composition, but did not significantly alter cognitive symptoms, as assessed by multiple assays. In cortex, LR3 treatment improved some facets of pathology, including a reduction in filamentous plaques, and increase in inert plaques, corresponding with a reduction in low molecular weight Aβ oligomers. <i>In vitro</i>, uptake of Aβ<sub>1-42</sub> peptide by BV2 cells was enhanced by LR3-IGF-1, which was also found to promote gene pathways implicated in actin remodeling and endocytosis.<h4>Conclusions</h4>LR3 promotes favorable effects on Aβ plaque remodeling in cortex of male 5XFAD mice but fails to preserve aspects of behavior or memory. While these data do not support LR3 as a monotherapy <i>per se</i>, they do warrant further investigation into its potential for combinatorial formulations aimed at targeting the complexity of AD.
Background
The paper addresses the potential role of IGF-1 LR3 in Alzheimer's disease, specifically its effects on amyloid plaques and cognitive function. Prior studies have suggested that IGF-1 may influence neurodegenerative processes, but the exact impact on cognitive outcomes remains unclear. This study is significant as it explores a novel delivery method (intranasal) for IGF-1 LR3 in a relevant animal model.
Methods
The study utilized male 5XFAD mice, a model for Alzheimer's disease, to assess the effects of IGF-1 LR3. The specific dose, duration, and route of administration were not detailed in the abstract. Primary outcomes included amyloid plaque remodeling and cognitive function assessments.
Results
The primary endpoint related to amyloid plaque remodeling was reported, but specific numeric findings regarding cognitive function were not provided. The study indicates that while amyloid plaques were remodeled, cognitive function was not preserved.
Interpretation
This study's findings suggest that while IGF-1 LR3 may affect amyloid pathology, it does not translate to cognitive preservation in this model. This contrasts with some literature suggesting cognitive benefits from IGF-1 treatment. Limitations include the reliance on a rodent model and the lack of detailed cognitive outcome metrics, which may affect the applicability of results to human conditions.
Key findings
- Amyloid plaque remodeling observed, but cognitive function not preserved.
- Not reported in abstract.
- Not reported in abstract.
Limitations
- Rodent model may not translate to humans.
- Specific numeric findings not reported.
- No details on dosage or duration of treatment.