Oral arginine reduces amyloid buildup in Alzheimer’s models
Alzheimer's disease (AD), a progressive neurodegenerative disorder, is one of the leading causes of dementia worldwide, and currently has no definitive cure. Although antibody-based therapies that target amyloid β (Aβ) have recently been developed, their clinical effectiveness remains limited. These treatments can be costly and cause immune-related side effects, highlighting the need for safer, affordable, and widely accessible approaches that can slow the progression of AD.
In a groundbreaking study, researchers from Kindai University and collaborating institutions have discovered a promising natural solution. They found that oral administration of arginine, a safe and affordable amino acid, effectively suppresses Aβ aggregation and its toxic effects in animal models of AD. This discovery offers a potential breakthrough in the fight against Alzheimer's.
The research team, led by Prof. Yoshitaka Nagai and Graduate Student Kanako Fujii, demonstrated that arginine can inhibit Aβ42 aggregation in vitro. They then evaluated its effectiveness in two AD models: a Drosophila model with the Arctic mutation (E22G) and an AppNL-G-F knock-in mouse model with familial AD mutations. In both models, arginine significantly reduced Aβ accumulation and alleviated Aβ-induced toxicity.
Prof. Nagai emphasizes the exciting implications of their findings: "Arginine's ability to suppress Aβ aggregation both in vitro and in vivo is remarkable. What's more, its clinical safety and low cost make it a highly promising candidate for repositioning as a therapeutic option for AD."
In the mouse model, oral arginine decreased amyloid plaque deposition and insoluble Aβ42 levels in the brain. It also improved behavioral performance and reduced neuroinflammation, suggesting broader neuroprotective and anti-inflammatory actions.
This study opens up new possibilities for developing arginine-based strategies for neurodegenerative diseases caused by protein misfolding and aggregation. Given its excellent safety profile and low cost, arginine could be rapidly translated to clinical trials for Alzheimer's and potentially other related disorders.
The researchers highlight the potential of drug repositioning, repurposing existing, safe compounds for new therapeutic uses, as an efficient pathway toward accessible Alzheimer's treatments. With arginine's clinical use in Japan and its high safety and brain permeability, it may overcome early development barriers.
Further preclinical and clinical studies are needed to establish optimal dosing regimens and replicate these findings in humans. However, this study provides compelling proof of concept that simple nutritional or pharmacological supplementation could mitigate amyloid pathology and improve neurological outcomes.
This research not only deepens our understanding of Aβ aggregation dynamics but also highlights a readily implementable and cost-effective strategy that could ultimately benefit the growing global population affected by AD.
