ABSTRACT
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.
Subject(s)
Cytotoxicity, Immunologic , Inflammation/etiology , Islets of Langerhans Transplantation/methods , Prostheses and Implants , Transplantation, Heterologous , Acrylic Resins/administration & dosage , Animals , Exudates and Transudates/cytology , Flow Cytometry , Graft Rejection , Mice , Peritoneal Cavity/cytology , RatsSubject(s)
Cytotoxicity, Immunologic/immunology , Inflammation/chemically induced , Membranes, Artificial , Animals , Capsules , Cell Death/drug effects , Inflammation/prevention & control , Microbial Collagenase/administration & dosage , Microbial Collagenase/adverse effects , Pancreatic Elastase/administration & dosage , Pancreatic Elastase/adverse effects , Riboflavin/administration & dosage , Riboflavin/adverse effects , Tumor Cells, CulturedABSTRACT
A new process for embedding cells in agarose is described. Beads were obtained by extruding an ultralow gelling temperature agarose solution in a capillary containing a hydrophobic medium flowthrough. The toxicity of the procedure has been evaluated by monitoring the energy status of agarose-embedded C(6) glioma cells with (31)P nuclear magnetic resonance (NMR). Suspension and microbead cultures of hybridoma cell line were compared. In suspension culture the number of cells and the antibody concentrations increased for 5 days before the stationary phase began, when the cultures were stopped. In agarose bead cultures, the gel provided an enormous support surface area (50 m(2)/ mL of gel). It was possible to seed 20-fold more cells. The gel pressure modified the proliferative process and antibody pattern secretion. In particular, the antibodies could be harvested for two weeks.
ABSTRACT
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.
Subject(s)
Adrenal Cortex/transplantation , Graft Survival , Inflammation/prevention & control , Adrenal Cortex/cytology , Adrenal Cortex/ultrastructure , Animals , Capsules , Flow Cytometry , Granuloma/pathology , Granuloma/prevention & control , Lymphocytes/cytology , Lymphocytes/immunology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred Strains , Microscopy, Electron , SepharoseABSTRACT
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.
Subject(s)
Acrylamides/chemistry , Biocompatible Materials , Capsules , Pituitary Gland/metabolism , Sepharose/chemistry , Acrylamide , Acrylamides/toxicity , Animals , Cells, Cultured , Emulsions/chemistry , Female , Pituitary Gland/drug effects , Polymers , Prolactin/metabolism , Rats , Rats, Inbred Strains , Sepharose/toxicityABSTRACT
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.
Subject(s)
Acrylamides/pharmacology , Acrylic Resins/pharmacology , Complement Activation/drug effects , Cross-Linking Reagents , Capsules , Complement C3 , Complement C3c , Complement C4 , Materials Testing , Piperazines , Zymosan/pharmacologyABSTRACT
One of the implantation problems in immunoprotected living cells is the appearance of local inflammatory phenomena around microcapsules. Some of the mediators released in such pathophysiological conditions were tested. A toxic action of compounds such as elastase, collagenase was evidenced. Interleukins 1 and 2 revealed no cytotoxicity within the test limits on the experimental cellular model chosen. These results underline the importance of inflammatory mediators released by adjacent cells of the implant.