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“Seeing” Stem Cells Helps in Fight Against Peripheral Arterial Disease Dorota A Kedziorek, MD, Piotr Walczak, MD, PhD, Yingli Fu, PhD, Frank Wacker, MD, Dara L Kraitchman, VMD, PhD Johns Hopkins University School of Medicine Russell H. Morgan Department of Radiology and Radiological Science Baltimore, MD Presenter Disclosure Information I will discuss off label use and/or investigational use of contrast agents in my presentation. Financial Relationships to disclose: • Bayer Schering Pharma AG • Boston Scientific Corporation • Surgi-vision, Inc. Peripheral Arterial Disease (PAD) • PAD affects ~8-12 million Americans. • 1 in 5 patients with critical limb ischemia have severe enough disease to be ineligible for conventional medical or surgical revascularization therapy. • Gene, protein, and cellular therapies offer an alternative means to attack the response to occlusion by “therapeutic arteriogenesis.” How to create new blood vessels? Problems with Current Cell Therapy 1. Cannot “see” where cells are injected. Needles marking injection sites Problems with Cell Therapy 1. Cannot “see” where cells are injected. 2. Large number of cells die after administration Solution: Place Cells in “Seaweed Bubble” APA ≡Alginate-poly-L-lysine-alginate Lim and Sun, Science 1980 Biocompatible - Provides surface for cell adhesion Selective permeability - Blocks antibody and cellular destruction – good for transplanted O2, Glu donor cells VEGF, PGE2, - Permits diffusion of IL-8, IL-6, HGF, etc. nutrients and waste products. IgG, IgM Courtesy: Ming Chen What If Imaging Visible Capsules Were Possible? “Liquid Oxygen” •Trimodal Imaging Agent •Bromine – X-ray •Perfluorocarbon – U/S •19F - MRI Imaging Sensitivity to PFOB Caps 5 10 25 capsules/dot: c-arm CT 19F MRI 2 cm Fu et al., SCMR 2009 X-ray Monitoring of PFOB Caps Delivery in a Rabbit PAD Model Immediately after injection Unlabeled PFOB Caps Five weeks post-injection Can see the PFOB Cap, but is the cell alive? Bioluminescence Imaging Luciferin Oxyluciferin Luciferase Bioluminescence Signal ATP High Light Cells expressing luciferase Low A Bioluminescence imaging of Embryonic Stem Cells P/s/cm2/sr P/s/cm2/sr P/s/cm2/sr P/s/cm2/sr 10 10 10 10 10 8 8 8 8 8 6 6 6 6 6 4 Control P/s/cm2/sr 4 ×103 4 ×105 ×105 4 ×106 4 2 2 2 2 2 0 0 0 0 0 Day 5 Day 10 ×106 Cao F, et al. Circulation 2006;113:1005-14 Reporter Probe Dose Intravenous Injection: •Rabbit =10 X Rat! •Patient = 150 X Rat! Animal study #1 Immediately post injection 24 hrs post injection PFOB encapsulated transfected MSCs “Naked” transfected MSCs “Naked” transfected MSCs How to Administer Reporter Probe? BLI Immediately post injection Pure alginate caps PFOB encapsulated transfected MSCs DynaCT – 24 hrs post Using Interventional Radiology to Guide Reporter Probe Injections Immediately post injection C-arm CT Targeting Pure alginate caps PFOB encapsulated transfected MSCs 24 hrs post injection PFOB encapsulated transfected MSCs 48 hrs post injection PFOB encapsulated transfected MSCs Seaweed Plus Liquid Oxygen Plus Firefly “Brew” Seaweed (Protanal®) Liquid Oxygen (Oxygent®): _ Firefly • Happy Cells • FDA-approved agents in bubble • Better able to survive to create new blood vessels for PAD • Visible by X-ray for Interventional Radiologist to tailor therapy Acknowledgments • • • • • Aravind Arepally Brad Barnett Jeff Bulte Lawrence Hofmann Gary Huang • • • • • • • Mark Pittenger Randall Young Christine Lorenz Tina Ehtati Steve Shea Wesley Gilson Robert Krieg NIH R01-HL63439, R01-HL73223, K08 EB004348, R21-HL89029, R01-EB007825, and MD-SCRFII-0399-00 Conclusions • “Seaweed plus liquid oxygen plus firefly brew”: Enhanced cell viability Enables visualization with X-ray and Optical Imaging • C-arm CT provides a minimally invasive method to target the reporter probe for localized injections to our X-ray visible capsules to reduce dose of reporter probe. • First demonstration of X-ray visible stem cell therapeutic with ability to measure cell viability by imaging. Trimodal Imaging MRI c-arm CT US