Adipose tissue-derived mesenchymal stem cell extracellular vesicles enhance amyloid-beta degradation in an in vitro Alzheimer's model

Objective: Alzheimer's disease (AD) is a progressive neurodegenerative disorder lacking effective treatment. Mesenchymal stem cells (MSCs) and extracellular vesicles (EVs) have shown promise in degrading amyloid beta (A(3) plaques due to their low immunogenicity and ability to mediate intercellular communication. This study investigates the therapeutic potential of EVs derived from human adipose tissue MSCs (hAT-MSCs) and preconditioned human adipose tissue MSCs in an in vitro AD model. Methods: MSCs characterized by flow cytometry and differentiation assays. hAT-MSCs stimulated with hydrogen peroxide (H2O2) or a cytokine complex (CC; TNF-alpha, IL-1(3, IFN-gamma). EVs were isolated via ultracentrifugation and analyzed by electron microscopy and Zetasizer. An in vitro AD model was established using neural-differentiated SH-SY5Y cells treated with A(3 peptides. Differentiation and A(3 degradation were assessed using immunocytochemistry, qRT-PCR, and ELISA. Results: EVs derived from cytokine complex stimulated hAT-MSCs significantly reduced A(3 plaque size and intensity compared to EVs from unstimulated or H2O2-stimulated cells. When immunocytochemistry images were analyzed using ImageJ, A(3 levels were found to be highest in the Alzheimer's group and lowest in the CC-EV group. According to ELISA analyses, no significant difference was observed between the Alzheimer's model (a1) and the hAT-MSC-EVs (a3) groups, whereas both the H2O2-EV (a4) and CC-EV (a5) groups showed a significant reduction compared to the control (**** P <= 0,0001) Conclusion: These findings suggest that cytokine-stimulated hAT-MSC-derived EVs effectively promote A(3 degradation and represent a promising cell-free therapeutic strategy for AD.