Dados do Trabalho

Título/Title/Titulo

Dissociation and reconstitution of mesenchymal stem cell membranes to generate particles for cellular therapy

Introdução/Introduction/Introdución

Mesenchymal stem cells (MSC) are a promising therapy for degenerating and immunological disorders. However, MSC therapy is associated with risks and practical difficulties that come with the use of living cells. Cells may transform and even though MSC are believed to have a short survival after intravenous infusion, even a single surviving transformed cell forms a risk for tumor formation.

Objetivos - Metodologia - Resultados - Discussão dos Resultados/Objectives - Methodology - Results - Discussion of Results/Objetivos - Metodología - Resultados - Discusión de los resultados

Objectives: To reduce risks associated with MSC infusion and improve the distribution in the body, we generated MSC membrane particles (MP) from humans (hMP) and C57BL/6 mice (mMP).
Methods: MSC were isolated from human and C57BL/6 mouse adipose tissue and the cells were primed with LPS (mice) or IFN-ƴ (human) to enhance their immunomodulatory effects. MP were manually generated by lysing MSC in hypotonic buffer, removal of organelles and soluble proteins by centrifugation and ultrafiltration respectively. Analysis of absolute size distribution and concentration of MP were performed using NanoSight particle tracking and their morphology were evaluated by Confocal microscope.
Results and Discussion: NTA indicated that the size of the particles ranged from 64 to 685nm, and the mode size of the samples was 149.2 ± 20.2nm and 125.9 ± 9.1nm for hMP and mMP, respectively. There was no significant difference in size distribution (MP/MSC) between hMP and mMP. Confocal imaging revealed that MP consist of a population of particles heterogeneous in size with most of the particles showing a size of less than 200nm but some showing larger sizes. This result confirms the NTA analysis. This new methodology produces particles with an optimized physical size to avoid trapping in the lung. This new physical conformation of MSC furthermore avoids formation of tumors, decreases the risk for immune responses directed against injected cells and avoids potential changing behavior of the therapeutic such as with living cells.

Considerações Finais/Final considerations/Consideraciones finales

Complications related to the size of MSC during systemic or local injection can be minimized with the MP therapy. Additional studies, both in vitro and in vivo, are needed to improve our understanding the mechanisms of action of this potential immunosuppressive tool.

Palavras-chave/Key words/Palabras clave

Mesenchylam stem cells; cell therapy; membrane particles