Embedded Adrenal Cells Graft Reduced Local and Early Nonspecific Inflammatory Phenomena Which Follow Agarose Beads Implantation

Microencapsulation of adrenal cells is proposed for reducing the nonspecific inflammatory reaction observed around polymer implants. This hypothesis was tested by comparing both host cellular reaction and the surrounding graft cell populations which appeared either when agarose embedded cells or when empty agarose beads were implanted. Our results showed that the fibrotic material that surrounded the implanted empty agarose microbeads was not as severe and important when adrenal cells were present. Similarly, T lymphocyte population surrounding the graft was considerably reduced together with the percentage of CD4 and CD8 positive cell subpopulations. The activation macrophage marker IaD disappeared. Our results support the hypothesis that embedded adrenal cells may be a suitable solution for reducing early inflammatory events due to microcapsules implantation.

Peritoneal exudates from microencapsulated rat islets of Langerhans xenografted mice presenting characteristics of potentially cytotoxic non-specific inflammation

Grafted polyacrylamide microencapsulated islets of Langerhans in the peritoneal cavity of mice did not survive more than a few days, perhaps owing to a non-specific inflammatory reaction or an immune rejection. To assess the two hypotheses, we used flow cytometry (FACS) to analyse cell populations of empty or islet-loaded microcapsules grafted in the peritoneal cavity of mice, and performed cytotoxic assays with proteases secreted by inflammatory cells. An immune rejection did not seem to occur, but the degree of inflammation could explain the short life of the grafts.

Microencapsulation of isolated pituitary cells by polyacrylamide microlatex coagulation on agarose beads

Microlatex beads of homogenous size were made by polymerization of a mixture of acrylamide/bisacrylamide dispersed in a microemulsion. The microlatex was aggregated by dilution of the microemulsion in acrylamide solutions. The aggregates were then coagulated by polymerization at the interfaces of agarose beads circulating in a capillary tube containing paraffin oil. Biocompatibility was tested on isolated pituitary cells microencapsulated by this procedure.

Crosslinking with diacrylylpiperazine (PIP) reduces activation of complement by polyacrylamide microcapsules

Activation of the complement system in vitro by a series of microcapsules based on polylysine, alginate or polyacrylamide was determined. Least activation was observed with microcapsules whose outer layer was composed of polyacrylamide. Activation was further reduced using diacrylylpiperazine instead of bisacrylamide as crosslinker.