““Seeing” Stem Cells Helps in Fight Seeing” Stem Cells Helps in Fight Against Peripheral Arterial DiseaseAgainst Peripheral Arterial Disease

Dorota A Kedziorek, MD, Piotr Walczak, MD, PhD, Yingli Fu, PhD, Frank Wacker, MD,

Dara L Kraitchman, VMD, PhDJohns Hopkins University

School of MedicineRussell H. Morgan Department of Radiology and

Radiological ScienceBaltimore, MD

Presenter Disclosure InformationPresenter 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)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?How to create new blood vessels?

Problems with Current Cell TherapyProblems with Current Cell Therapy

1. Cannot “see” where cells are injected.

Needles marking injection sites

Problems with Cell TherapyProblems with Cell Therapy

1. Cannot “see” where cells are injected.

2. Large number of cells die after administration

Solution: Place Cells in “Seaweed Bubble”Solution: Place Cells in “Seaweed Bubble”

Courtesy: Ming Chen

Biocompatible- Provides surface for cell adhesion

Selective permeability- Blocks antibody and cellular destruction – good for transplanted donor cells- Permits diffusion of nutrients and waste products.

Lim and Sun, Science 1980 APA ≡APA ≡Alginate-poly-L-lysine-alginate

VEGF, PGE2,

IL-8, IL-6, HGF, etc.

IgG, IgM

O2, Glu

What If Imaging Visible Capsules Were What If Imaging Visible Capsules Were Possible?Possible?

•Trimodal Imaging Agent•Bromine – X-ray•Perfluorocarbon – U/S•19F - MRI

“Liquid Oxygen”

Imaging Sensitivity to PFOB CapsImaging Sensitivity to PFOB Caps5 10 25

2 cm

c-arm CT

19F MRI

Fu et al., SCMR 2009

capsules/dot:

Five weeks post-injection

X-ray Monitoring of PFOB Caps Delivery in X-ray Monitoring of PFOB Caps Delivery in a Rabbit PAD Model a Rabbit PAD Model

Immediately after injection

UnlabeledPFOB Caps

Can see the PFOB Cap, Can see the PFOB Cap, but is the cell alive?but is the cell alive?

Bioluminescence ImagingBioluminescence Imaging B

iolu

min

esce

nce

Sig

nal High

Low

ATP

Light

Luciferin Oxyluciferin

Luciferase

Cells expressing luciferase

Day 5

10

8

6

4

2

0

×103

10

8

6

4

2

0

×105

10

8

6

4

2

0

×105

10

8

6

4

2

0

×106

10

8

6

4

2

0

×106

Control Day 10

P/s/cm2/srP/s/cm2/srP/s/cm2/srP/s/cm2/srP/s/cm2/sr

A Bioluminescence imaging of Embryonic Bioluminescence imaging of Embryonic Stem CellsStem Cells

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

PFOB encapsulated transfected MSCs

“Naked” transfected MSCs

“Naked” transfected MSCs

Immediately post injection 24 hrs post injection

How to Administer Reporter Probe?How to Administer Reporter Probe?

DynaCT – 24 hrs post

PFOB encapsulated transfected MSCs

Immediately post injection

Pure alginate caps

BLI

Using Interventional Radiology to Guide Using Interventional Radiology to Guide Reporter Probe InjectionsReporter Probe Injections

C-arm CT TargetingC-arm CT TargetingPFOB encapsulated transfected MSCs

Immediately post injection

48 hrs post injection

Pure alginate caps

24 hrs post injection

PFOB encapsulated transfected MSCs

PFOB encapsulated transfected MSCs

Seaweed Plus Liquid Oxygen Seaweed Plus Liquid Oxygen Plus Firefly “Brew”Plus Firefly “Brew”

_

Seaweed (Protanal®) • 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

LiquidOxygen(Oxygent®):

Firefly

Acknowledgments• Mark Pittenger• Randall Young• Christine Lorenz• Tina Ehtati• Steve Shea• Wesley Gilson• Robert Krieg

• Aravind Arepally• Brad Barnett• Jeff Bulte• Lawrence Hofmann• Gary Huang

NIH R01-HL63439, R01-HL73223, K08 EB004348, R21-HL89029, R01-EB007825, and MD-SCRFII-0399-00

ConclusionsConclusions• “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 ImagingTrimodal Imaging

MRI

c-arm CT

US