title: Noninvasive assessment of tissue-engineered graft viability by oxygen-17 magnetic resonance spectroscopy.
abstract: Transplantation of macroencapsulated tissue-engineered grafts (TEGs) is being investigated as a treatment for type 1 diabetes, but there is a critical need to measure TEG viability both in vitro and in vivo. Oxygen deficiency is the most critical issue preventing widespread implementation of TEG transplantation and delivery of supplemental oxygen (DSO) has been shown to enhance TEG survival and function in vivo. In this study, we demonstrate the first use of oxygen-17 magnetic resonance spectroscopy (17O-MRS) to measure the oxygen consumption rate (OCR) of TEGs and show that in addition to providing therapeutic benefits to TEGs, DSO with17O2can also enable measurements of TEG viability. Macroencapsulated TEGs containing βTC3 murine insulinoma cells were prepared with three fractional viabilities and provided with17O2. Cellular metabolism of17O2into nascent mitochondrial water (H217O) was monitored by17O-MRS and, from the measured data, OCR was calculated. For comparison, OCR was simultaneously measured on a separate, but equivalent sample of cells with a well-established stirred microchamber technique. OCR measured by17O-MRS agreed well with measurements made in the stirred microchamber device. These studies confirm that17O-MRS can quantify TEG viability noninvasively. Biotechnol. Bioeng. 2017;114: 1118-1121. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 Sixth Street SE, Minneapolis, Minnesota, 55455.
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Einstein
authors.affiliation: Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 Sixth Street SE, Minneapolis, Minnesota, 55455.
authors.forename: Bradley P
authors.initials: BP
authors.lastname: Weegman
authors.affiliation: Department of Surgery, University of Arizona, Tucson, Arizona.
authors.forename: Jennifer P
authors.initials: JP
authors.lastname: Kitzmann
authors.affiliation: Department of Surgery, University of Arizona, Tucson, Arizona.
authors.forename: Klearchos K
authors.initials: KK
authors.lastname: Papas
authors.affiliation: Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, 2021 Sixth Street SE, Minneapolis, Minnesota, 55455.
authors.forename: Michael
authors.initials: M
authors.lastname: Garwood
mesh_terms: D000818:Animals; D021522:Bioartificial Organs; D002460:Cell Line; D006085:Graft Survival / Q000502:physiology*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D051379:Mice; D008954:Models, Biological; D010103:Oxygen Isotopes / Q000032:analysis / Q000378:metabolism*; D019397:Pancreas, Artificial; D023822:Tissue Engineering
chemical_list: D010103:Oxygen Isotopes
keywords: bioartificial pancreas; macroencapsulation; magnetic resonance spectroscopy; tissue-engineered graft; viability assessment