Reduction of inflammatory reaction in the use of purified alginate microcapsules

Abstract

Alginate, a polysaccharide extracted from brown seaweed, remains the most widely used biomaterial for immobilizing cells to be transplanted, because of the good viability of the encapsulated cells and the relatively ease of processing for cell encapsulation. However, the main drawback is the immune reaction in vivo. To overcome this problem, we have demonstrated a modified Korbutt method for alginate purification. After alginate microcapsules were manufactured, NIH/3T3 fibroblast cells were seeded in purified and non-purified alginate microcapsules, and the cell proliferation was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide assay. Reverse transcriptase-polymerase chain reaction was performed to assess the mRNA expression of RAW 264.7 macrophage cells for inflammation cytokines such as TNF-α. Purified and non-purified alginate microcapsules were implanted into Wister rats, and subsequently extracted after 1-2 weeks. Tissues surrounding the implants were harvested and underwent histological evaluation through H&E staining and immunohistochemical evaluation through ED-1 staining. In this result, contaminated materials in the purified alginate were eliminated by purification process. Thereby, density of inflammatory cell decreased about 30% more than non-purified alginate and thickness of fibrotic wall decreased about three times. In concluding, the purified alginate is anticipated to be highly potent for numerous biomaterial applications.

Alginate Microencapsulated Hepatocytes Optimised for Transplantation in Acute Liver Failure

“…Our findings demonstrated that both EMBs and HMBs did not elicit immune activation in vitro . This is probably due to ultrapure sodium alginate being used and is consistent with other studies testing inflammation and immune reaction related to the purity of alginate [12] , [32] . Rokstad et al (2011) showed that alginate microbeads are complement compatible [33] .…”

Unsaturated guluronate oligosaccharide enhances the antibacterial activities of macrophages

“…8). Although previous reports have shown that alginate has immunomodulatory functions (3,17), we believe that our study is the first to thoroughly investigate the mechanisms of how alginate-derived oligosaccharides improve the host defense against bacterial infection.…”

The relationship between the inflammatory response and cell adhesion on alginate-chitosan-alginate microcapsules after transplantation

“…The main methods for inhibiting cell adhesion have included the use of optimizing materials, which change or modify the surface properties of the microcapsules, and screening the transplantation site. For example, microcapsules made from purified alginate materials have a longer lifespan than nonpurified alginate microcapsules coated with (short‐chain alginate)‐ co ‐MPEG have a longer lifespan than conventional alginate, and microcapsules transplanted into the bone marrow survive longer than those transplanted under the kidney capsule . In these studies, the extent of cell adhesion was determined by examining tissue sections from biopsies of the enwrapped microcapsules explanted after implantation.…”