Studies on small (<350 ?m) alginate-poly-L-lysine microcapsules. III. Biocompatibility of smaller versus standard microcapsules

✍ Scribed by Robitaille, Robert ;Pariseau, Jean-Fran�ois ;Leblond, Fran�ois A. ;Lamoureux, Michel ;Lepage, Yves ;Hall�, Jean-Pierre

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 283 KB
• Volume: 44
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/(sici)1097-4636(199901)44:1<116::aid-jbm13>3.0.co;2-9

✦ Synopsis

Microencapsulation of islets of Langerhans has been proposed as a means of preventing their immune destruction following transplantation. Microcapsules of diameters <350 m made with an electrostatic pulse system present many advantages relative to standard microcapsules (700-1500 m), including smaller total implant volume, better insulin kinetics, better cell oxygenation, and accessibility to new implantation sites. To evaluate their biocompatibility, 200, 1000, 1120, 1340, or 3000 of these smaller microcapsules (<350 m) or 20 standard microcapsules (1247 ± 120 m) were implanted into rat epididymal fat pads, retrieved after 2 weeks, and evaluated histologically. The average pericapsular reaction increased with the number of small microcapsules implanted (p < 0.05; 3000 vs. 200, 3000 vs. 1000, and 1000 vs. 200 microcapsules). At equal volume and alginate content, standard microcapsules caused a more intense fibrosis reaction than smaller microcapsules (p < 0.05). In addition, 20 standard microcapsules elicited a stronger pericapsular reaction than 200 and 1000 smaller microcapsules (p < 0.05) although the latter represented a 3.4-fold larger total implant surface exposed. We conclude that microcapsules of diameters <350 m made with an electrostatic pulse system are more biocompatible than standard microcapsules.