title: Noninvasive Tracking of Encapsulated Insulin Producing Cells Labelled with Magnetic Microspheres by Magnetic Resonance Imaging.
abstract: Microencapsulated islets are usually injected free-floating into the peritoneal cavity, so the position of the grafts remains elusive after transplantation. This study aims to assess magnetic resonance imaging (MRI) as a noninvasive means to track microencapsulated insulin producing cells following transplantation. Encapsulated insulin producing cells (MIN6 and human islets) were labelled with magnetic microspheres (MM), assessed for viability and insulin secretion, and imaged in vitro using a clinical grade 3 T MRI and in vivo using both clinical grade 3 T and research grade 11.7 T MRI. Fluorescent imaging demonstrated the uptake of MM by both MIN6 and human islets with no changes in cell morphology and viability. MM labelling did not affect the glucose responsiveness of encapsulated MIN6 and islets in vitro. In vivo encapsulated MM-labelled MIN6 normalized sugar levels when transplanted into diabetic mice. In vitro MRI demonstrated that single microcapsules as well as clusters of encapsulated MM-labelled cells could be visualised clearly in agarose gel phantoms. In vivo encapsulated MM-labelled MIN6 could be visualised more clearly within the peritoneal cavity as discrete hypointensities using the high power 11.7 T but not the clinical grade 3 T MRI. This study demonstrates a method to noninvasively track encapsulated insulin producing cells by MM labelling and MRI.
authors.affiliation: Commonwealth Scientific and Industrial Research Organization, Future Manufacturing Flagship, North Ryde, NSW 2113, Australia; Diabetes Transplant Unit, Prince of Wales Hospital, Randwick, NSW 2031, Australia; School of Medical Sciences, Faculty of Medicine, University of New South Wales, Randwick, NSW 2031, Australia.
authors.forename: Vijayaganapathy
authors.identifier: 0000-0001-5844-6468
authors.initials: V
authors.lastname: Vaithilingam
authors.affiliation: Diabetes Transplant Unit, Prince of Wales Hospital, Randwick, NSW 2031, Australia.
authors.forename: Mandy M W
authors.initials: MM
authors.lastname: Yim
authors.affiliation: Diabetes Transplant Unit, Prince of Wales Hospital, Randwick, NSW 2031, Australia.
authors.forename: Jayne L
authors.initials: JL
authors.lastname: Foster
authors.affiliation: Nanoscale Organisation and Dynamics Group, School of Science and Health, University of Western Sydney, Campbelltown, NSW 2560, Australia.
authors.forename: Timothy
authors.identifier: 0000-0002-7898-8202
authors.initials: T
authors.lastname: Stait-Gardner
authors.affiliation: Department of Surgery, University of Illinois at Chicago, Chicago, IL 60612, USA.
authors.forename: Jose
authors.initials: J
authors.lastname: Oberholzer
authors.affiliation: Commonwealth Scientific and Industrial Research Organization, Future Manufacturing Flagship, North Ryde, NSW 2113, Australia; Diabetes Transplant Unit, Prince of Wales Hospital, Randwick, NSW 2031, Australia; School of Biomedical Science, Discipline Physiology, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Bernard E
authors.identifier: 0000-0003-1472-0394
authors.initials: BE
authors.lastname: Tuch
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D006801:Humans; D066298:In Vitro Techniques; D050417:Insulin-Secreting Cells / Q000637:transplantation*; D016381:Islets of Langerhans Transplantation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059346:Magnets; D051379:Mice; D008863:Microspheres; D019737:Transplants / Q000000981:diagnostic imaging*