Measurement of Dissolved Oxygen by 19F MRI of Microcapsules Implanted IP in Non-Human Primates.
1Surgery, Emory University, Atlanta, GA
2Surgery, University of Minnesota, Minneapolis, MN
3Radiology, University of Minnesota, Minneapolis, MN
4Sylvatica Biotech, Inc., Charleston, SC
5Surgery, University of Arizona, Tucson, AZ
6School of Chemical and Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA
7School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA
Meeting: 2017 American Transplant Congress
Abstract number: B130
Keywords: Bioengineering, Islets, Magnetic resonance imaging, Primates
Session Information
Session Name: Poster Session B: Ischemic Injury and Organ Preservation Session II
Session Type: Poster Session
Date: Sunday, April 30, 2017
Session Time: 6:00pm-7:00pm
Presentation Time: 6:00pm-7:00pm
Location: Hall D1
Since our encapsulated NHP islet allografts and porcine islet xenografts fail after i.p. transplantation in immunosuppressed NHPs without a cellular or humoral immune response, we hypothesized that peritoneal dissolved oxygen (DO) levels may be inadequate to support islet function over time. Our objective was to measure the partial pressure of oxygen (pO2) i.p. in normal NHPs non-invasively by 19F magnetic resonance (MR).
On day 0, three Rhesus macaques received acellular 19F perfluoro-15-crown-5 ether (PFCE) alginate capsules (quality control by 19F MR) via an i.p. catheter. Peritoneal pO2 was measured noninvasively by MR using 19F-MR relaxometry methods (Einstein et al. 2016, Tissue Engineering: Part C, 11:1009-1017). The 3 NHPs were reevaluated on day 7 using the same procedures. The animals were euthanized for gross evaluation of the capsules and their distribution.
Immediately after infusion, 1H-MR showed that the capsules were clustered near the catheter tip, and the average peritoneal pO2 was 147±9 mmHg (165, 137, and 141 mmHg respectively). By day 7, after the capsules were widely distributed, the average pO2 was 61±11 mm Hg (66, 76, and 41 mmHg), strikingly similar to our previous findings of pO2 in mice by 19F MR (Goh et al. 2011, Biotechnol. Prog. 41:11115-1125). Free-floating capsules were “clean” with no adherent host cells, and many capsules were present on the surfaces of the omentum and other organs, with no evidence of fibrosis.
In conclusion, the relatively high pO2 at day 0 (147±9 mmHg) was likely due to the DO level in the capsules and infusion solution which were equilibrated with air (160 mmHg) prior to infusion. The pO2 level on day 7, after equilibration with peritoneal fluid, was near the level at which insulin secretion by rat islets becomes reduced (60±11 mmHg). These findings suggest that a method to optimize oxygenation of encapsulated islets is needed for i.p. transplantation.
CITATION INFORMATION: Safley S, Graham M, Garwood M, Papas K, Weegman B, Barber G, Lin E, Leisen J, Sambanis A, Hering B, Weber C. Measurement of Dissolved Oxygen by 19F MRI of Microcapsules Implanted IP in Non-Human Primates. Am J Transplant. 2017;17 (suppl 3).
To cite this abstract in AMA style:
Safley S, Graham M, Garwood M, Papas K, Weegman B, Barber G, Lin E, Leisen J, Sambanis A, Hering B, Weber C. Measurement of Dissolved Oxygen by 19F MRI of Microcapsules Implanted IP in Non-Human Primates. [abstract]. Am J Transplant. 2017; 17 (suppl 3). https://atcmeetingabstracts.com/abstract/measurement-of-dissolved-oxygen-by-19f-mri-of-microcapsules-implanted-ip-in-non-human-primates/. Accessed May 13, 2025.« Back to 2017 American Transplant Congress