title: The effect of capsule composition on the biocompatibility of alginate-poly-l-lysine capsules.
abstract: The encapsulation of islets of Langerhans in alginate-poly-l-lysine has been proposed as a method for the immunoprotection of transplanted islets. Although several capsule compositions have been reported, there has been no published study concerning the effect of capsule composition on the severity of the foreign body reaction. Empty capsules were prepared from high mannuronic acid alginate and were coated with: (1) poly-l-lysine alone, (2) poly-l-lysine plus high guluronic acid alginate, or (3) poly-l-lysine plus high mannuronic acid alginate. The capsules were placed in the renal subcapsular space or the peritoneal cavity, and retrieved after three weeks of histological examination. The recipients were WAG/01a, nude (athymic), diabetic BB, and non-diabetes prone BB rats. The severity of reaction to the capsules was determined by measuring the thickness of the pericapsular cell infiltrate or by a scoring system. The severity of the reaction to the capsules was strain-dependent in both the renal and peritoneal sites, with the BB and nude rats displaying the most severe responses. The degree of response was not affected by capsule composition in the renal subcapsular space, but in the peritoneum, the high mannuronic acid alginate capsules provoked the weakest response, and this type of capsule will be used for future transplantation work. The infiltrating cells were characterised by immunohistochemistry and electron microscopy and found to be mostly fibroblasts and macrophages.
authors.affiliation: Department of Surgery, University of Leicester, Leicester Royal Infirmary, UK.
authors.forename: H A
authors.initials: HA
authors.lastname: Clayton
authors.forename: N J
authors.initials: NJ
authors.lastname: London
authors.forename: P S
authors.initials: PS
authors.lastname: Colloby
authors.forename: P R
authors.initials: PR
authors.lastname: Bell
authors.forename: R F
authors.initials: RF
authors.lastname: James
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism; D006603:Hexuronic Acids / Q000737:chemistry; D007150:Immunohistochemistry; D007249:Inflammation / Q000503:physiopathology; D007668:Kidney / Q000473:pathology; D016030:Kidney Transplantation / Q000502:physiology; D011107:Polylysine / Q000031:analogs & derivatives* / Q000737:chemistry; D051381:Rats; D011913:Rats, Inbred BB; D011919:Rats, Inbred Strains; D011923:Rats, Nude; D013045:Species Specificity; D013601:T-Lymphocytes / Q000187:drug effects; D014184:Transplantation, Homologous; D014574:Uronic Acids / Q000737:chemistry
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D002214:Capsules; D006603:Hexuronic Acids; D014574:Uronic Acids; C051546:alginate-polylysine-alginate; C007896:guluronic acid; D011107:Polylysine; C008324:mannuronic acid