title: Highly poly(ethylene) glycolylated islets improve long-term islet allograft survival without immunosuppressive medication.
abstract: The surface modification of islets using poly(ethylene glycol) (PEG) is being studied as a means of preventing host immune responses against transplanted islets. In this study, to completely shield islets with PEG molecules, we increased the amount of PEG conjugated to islet surfaces, by multiple PEGylation or amplified PEGylation using poly-L-lysine, poly(allylamine), or poly(ethyleneimine), respectively. Amplified PEGylation was associated with islet cytotoxicity and functional impairment, but multiple PEGylation affected neither islet viability nor functionality. In addition, when triply PEGylated islets were allotransplanted into diabetic recipients, these islets survived in 3 of the 7 recipients for more than 100 days without any immunosuppressive treatment. Moreover, the blood glucose levels of these 3 recipients were stable and in the normal range. Immunohistochemical analysis showed that 3 of 7 triply PEGylated islets transplants survived for 100 days and that 4 that were rejected before day 20 were all immunologically protected from immune cells. However, unmodified islets were completely destroyed within 1 week. Consequently, we suggest that multiple PEGylation offers an effective means of reducing the immunogenicity of transplanted islets by increasing the amount of surface-bound PEG.
authors.affiliation: College of Pharmacy, Seoul National University, Seoul, South Korea.
authors.forename: Dong Yun
authors.initials: DY
authors.lastname: Lee
authors.forename: Sang Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Seulki
authors.initials: S
authors.lastname: Lee
authors.forename: Jong Hee
authors.initials: JH
authors.lastname: Nam
authors.forename: Youngro
authors.initials: Y
authors.lastname: Byun
mesh_terms: D000818:Animals; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology / Q000628:therapy; D004305:Dose-Response Relationship, Drug; D006085:Graft Survival / Q000187:drug effects* / Q000276:immunology; D007167:Immunotherapy; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D016381:Islets of Langerhans Transplantation / Q000276:immunology / Q000379:methods*; D008297:Male; D011073:Polyamines / Q000009:adverse effects; D000071228:Polyelectrolytes; D011092:Polyethylene Glycols / Q000378:metabolism* / Q000627:therapeutic use*; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D014184:Transplantation, Homologous
chemical_list: D011073:Polyamines; D000071228:Polyelectrolytes; D011092:Polyethylene Glycols