Vaithilingam Vijayaganapathy, Yim Mandy M W, Foster Jayne L, Stait-Gardner Timothy, Oberholzer Jose, Tuch Bernard E
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.
Diabetes Transplant Unit, Prince of Wales Hospital, Randwick, NSW 2031, Australia.
J Diabetes Res. 2016;2016:6165893. doi: 10.1155/2016/6165893. Epub 2016 Aug 18.
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.
微囊化胰岛通常以自由漂浮的形式注入腹腔，因此移植后移植物的位置难以确定。本研究旨在评估磁共振成像（MRI）作为一种非侵入性手段，用于追踪移植后的微囊化胰岛素产生细胞。将包封的胰岛素产生细胞（MIN6和人胰岛）用磁性微球（MM）标记，评估其活力和胰岛素分泌，并在体外使用临床级3T MRI进行成像，在体内使用临床级3T和研究级11.7T MRI进行成像。荧光成像显示MIN6和人胰岛均摄取了MM，细胞形态和活力无变化。MM标记不影响体外包封的MIN6和胰岛的葡萄糖反应性。体内包封的MM标记的MIN6移植到糖尿病小鼠体内后可使血糖水平正常化。体外MRI显示，单个微囊以及包封的MM标记细胞簇在琼脂糖凝胶模型中可以清晰地可视化。使用高功率11.7T MRI而非临床级3T MRI，体内包封的MM标记的MIN6在腹腔内可作为离散的低信号更清晰地可视化。本研究展示了一种通过MM标记和MRI非侵入性追踪包封的胰岛素产生细胞的方法。
