Exploring the potential of plasma and adipose mesenchymal stem cell-derived extracellular vesicles as novel platforms for neuroinflammation therapy.

Persistent reactive oxygen species (ROS) and neuroinflammation contribute to the onset and progression of neurodegenerative diseases, underscoring the need for targeted therapeutic strategies to mitigate these effects. Extracellular vesicles (EVs) show promise in drug delivery due to their biocompatibility, ability to cross biological barriers, and specific interactions with cell and tissue receptors. In this study, we demonstrated that human plasma-derived EVs (pEVs) exhibit higher brain-targeting specificity, while adipose-derived mesenchymal stem cells EVs (ADMSC-EVs) offer regenerative and immunomodulatory properties. We further investigated the potential of these EVs as therapeutic carriers for brain-targeted drug delivery, using Donepezil (DNZ) as the model drug. DNZ, a cholinesterase inhibitor commonly used for Alzheimer's disease (AD), also has neuroprotective and anti-inflammatory properties. The size of EVs used ranged from 50 to 300 nm with a surface charge below -30 mV. Both formulations showed rapid cellular internalization, without toxicity, and the ability to cross the blood-brain barrier (BBB) in a zebrafish model. The have analyzed the anti-inflammatory and antioxidant actions of pEVs-DNZ and ADMSC-EVs-DNZ in the presence of lipopolysaccharide (LPS). ADMSC-EVs significantly reduced the inflammatory mediators released by HMC3 microglial cells while treatment with pEVs-DNZ and ADMSC-EVs-DNZ lowered both phagocytic activity and ROS levels in these cells. In vivo experiments using zebrafish larvae revealed that both EV formulations reduced microglial proliferation and exhibited antioxidant effects. Overall, this study highlights the potential of EVs loaded with DNZ as a novel approach for treating neuroinflammation underlying various neurodegenerative diseases.