title: Time course of transforming growth factor-beta(1) (TGF-beta(1)) mRNA expression in the host reaction to alginate-poly-L-lysine microcapsules following implantations into rat epididymal fat pads.
abstract: Microencapsulation of islets of Langerhans within semipermeable membranes has been proposed to prevent their immune destruction after transplantation. However, the successful application of this method is impaired by a pericapsular reaction, which eventually induces graft failure. Our goal is to study the role of cytokines in the pathogenesis of this reaction, using the model of alginate-poly-L-lysine microcapsule implantation into Wistar rat epididymal fat pads (EFP). The specific objective of this study was to determine the time course of transforming growth factor (TGF)-beta(1) mRNA expression by semi-quantitative reverse transcriptase-polymerase chain reaction. Microcapsules induced an increase of TGF-beta(1) mRNA expression that reached a maximum 14 days after implantation. Seven, 14, 30, and 60 days after microcapsule implantation, the expression of TGF-beta(1) mRNA was significantly higher in pericapsular infiltrate cells than in nonimplanted EFP cells (p<0.05, p<0.0001, p<0.005, and p<0.01, respectively). Injection of physiological saline induced a small and gradual augmentation of TGF-beta(1) mRNA expression with a maximum 30 days after injection (p<0.01 vs. nonimplanted EFP cells). These results demonstrated that microcapsule implantation, in comparison with saline injection, induce an early, extended, and amplified TGF-beta(1) mRNA expression. This suggests that TGF-beta(1) plays a role in the pathogenesis of the pericapsular host reaction.
authors.affiliation: Centre de Recherche Guy-Bernier, Hôpital Maisonneuve-Rosemont, Montréal, Québec, H1T 2M4, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Robitaille
authors.forename: K
authors.initials: K
authors.lastname: Desbiens
authors.forename: N
authors.initials: N
authors.lastname: Henley
authors.forename: J P
authors.initials: JP
authors.lastname: Hallé
mesh_terms: D000464:Alginates / Q000009:adverse effects; D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects; D004822:Epididymis; D016381:Islets of Langerhans Transplantation / Q000276:immunology / Q000295:instrumentation*; D008297:Male; D008863:Microspheres; D011107:Polylysine / Q000009:adverse effects / Q000031:analogs & derivatives*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*
chemical_list: D000464:Alginates; D001672:Biocompatible Materials; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; C051546:alginate-polylysine-alginate; D011107:Polylysine