Biomimetic microcapsules of stem cells

Cell therapy is increasingly being used to address different diseases. Unlike classic medicines such as tablets or capsules, the new drugs combine biomaterials and cells to create systems for the release of therapeutic substances. The use of stem cells (those capable of differentiating into any type of cells) has been a great advance, being increasingly used by many research groups. However, in order to use the full potential of stem cells, it is necessary to design and develop systems that allow their proper transport and implantation.

Cellular microencapsulation consists in the immobilization of cells capable of secreting therapeutic substances for their release for long periods of time. Depending on the substances secreted by the encapsulated cells, their application will be different, addressing multiple pathologies.

Stem cells offer a series of advantages over other types of cells, so they are increasingly used in different areas of cell therapy. These are cells that secrete immunomodulatory substances, with the ability to modify the immune system. In addition, the organism in which they are implanted does not recognize them as foreign, being able to be incorporated into other species without producing immune rejection. On the other hand, they are capable of differentiating themselves into several cell types, opening up the range of possibilities they offer to other therapies such as regenerative medicine.

In this work of the NanoBioCel research group of the UPV / EHU, a biomimetic system has been developed, using the genetically modified mesenchymal D1 stem cells to secrete erythropoietin (EPO). The microcapsules, where the cells were immobilized, were modified using different concentrations of an adhesion peptide to improve cell survival.

The results obtained showed that the microcapsules containing the adhesion peptide improved the activity of the encapsulated stem cells, obtaining a greater secretion of EPO. In addition, it could be observed that the designed systems did not affect the immobilized cells, maintaining their characteristics. In a second phase, the experiments were carried out after implanting the microcapsules in animals, to see the influence that the environment could cause in vivo on the behavior of the encapsulated stem cells. Although no significant differences were observed between the immobilized stem cells in microcapsules made with or without the adhesion peptide during the study in mice, most of the cells remained alive throughout the assay. It was also observed that the secretion of the therapeutic substance was increasing over time.

Currently, several groups are conducting research, including clinical trials, related to cellular microencapsulation, since it is a promising therapeutic alternative for chronic diseases that currently lack effective treatment. On the other hand, the incorporation of stem cells in this technology offers new possibilities, facilitating the combination of drug secretion systems and regenerative medicine.

Reference:

Garate, A., Ciriza, J., Casado, J.G., Blázquez, R., Pedraz, J.L., Orive, G., Hernández, R.M. (2015) Assessment of the Behavior of Mesenchymal Stem Cells Immobilized in Biomimetic Alginate Microcapsules. Molecular Pharmaceutics. DOI: 10.1021/acs.molpharmaceut.5b00419