Guan Wang1,2, Yingli Fu1, Steven M Shea3, Shashank Sathyanarayana Hegde1, Dara L Kraitchman4,5. 1. Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, 600 N. Wolfe Street, 314 Park Building, Baltimore, MD, 21287, USA. 2. Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA. 3. Department of Radiology, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA. 4. Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, 600 N. Wolfe Street, 314 Park Building, Baltimore, MD, 21287, USA. dkraitc1@jhmi.edu. 5. Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, USA. dkraitc1@jhmi.edu.
Abstract
OBJECTIVES: Peripheral artery disease (PAD) affects 12-14% of the world population, and many are not eligible for conventional treatment. For these patients, microencapsulated stem cells (SCs) offer a novel means to transplant mismatched therapeutic SCs to prevent graft immunorejection. Using c-arm CT and 19F-MRI for serial evaluation of dual X-ray/MR-visible SC microcapsules (XMRCaps) in a non-immunosuppressed rabbit PAD model, we explore quantitative evaluation of capsule integrity as a surrogate of transplanted cell fate. MATERIALS AND METHODS: XMRCaps were produced by impregnating 12% perfluorooctylbromine (PFOB) with rabbit or human SCs (AlloSC and XenoSC, respectively). Volume and 19F concentration measurements of XMRCaps were assessed both in phantoms and in vivo, at days 1, 8 and 15 after intramuscular administration in rabbits (n = 10), by 3D segmenting the injection sites and referencing to standards with known concentrations. RESULTS: XMRCap volumes and concentrations showed good agreement between CT and MRI both in vitro and in vivo in XenoSC rabbits. Injected capsules showed small variations over time and were similar between AlloSC and XenoSC rabbits. Histological staining revealed high cell viability and intact capsules 2 weeks after administration. CONCLUSIONS: Quantitative and non-invasive tracking XMRCaps using CT and 19F-MRI may be useful to assess graft immunorejection after SC transplantation.
OBJECTIVES:Peripheral artery disease (PAD) affects 12-14% of the world population, and many are not eligible for conventional treatment. For these patients, microencapsulated stem cells (SCs) offer a novel means to transplant mismatched therapeutic SCs to prevent graft immunorejection. Using c-arm CT and 19F-MRI for serial evaluation of dual X-ray/MR-visible SC microcapsules (XMRCaps) in a non-immunosuppressed rabbit PAD model, we explore quantitative evaluation of capsule integrity as a surrogate of transplanted cell fate. MATERIALS AND METHODS:XMRCaps were produced by impregnating 12% perfluorooctylbromine (PFOB) with rabbit or human SCs (AlloSC and XenoSC, respectively). Volume and 19F concentration measurements of XMRCaps were assessed both in phantoms and in vivo, at days 1, 8 and 15 after intramuscular administration in rabbits (n = 10), by 3D segmenting the injection sites and referencing to standards with known concentrations. RESULTS: XMRCap volumes and concentrations showed good agreement between CT and MRI both in vitro and in vivo in XenoSC rabbits. Injected capsules showed small variations over time and were similar between AlloSC and XenoSC rabbits. Histological staining revealed high cell viability and intact capsules 2 weeks after administration. CONCLUSIONS: Quantitative and non-invasive tracking XMRCaps using CT and 19F-MRI may be useful to assess graft immunorejection after SC transplantation.