Stem Cells Build New Blood Stem Cells Build New Blood Vessels to Treat Peripheral Vessels to Treat Peripheral

Arterial Disease Arterial Disease Dorota A Kedziorek, MD, Yingli Fu, PhD, Piotr Walczak, MD, PhD, Tina Ehtiati, PhD, Steffi Valdeig, Gary Huang, Jeff W.M. Bulte, PhD,

Lawrence V. Hofmann, MD, Frank K. 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.• Siemens Healthcare USA

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.

• Normal signals to build new vessels are in foot, but problem higher in the leg.

How to create new blood vessels?How to create new blood vessels?

Problem with Current Cell TherapyProblem with Current Cell Therapy

Large numbers of cell are administered but fail to engraft due to:

• Poor oxygen/nutrient supply

• Inflammatory cytokines

• Survival signals by cell-cell contact lost

Zhang, Murry et al., J Mol Cell Cardiol 33, 907–921 (2001)

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

Problem with Current Cell TherapyProblem with Current Cell Therapy

Cannot “see” where cells are injected.

Needles marking injection sites

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”

C-arm CTC-arm CT

• Flat panel detector

• 16 second digital subtraction angiogram (DSA) acquisition

MRI & CT of Seaweed Bubble CellsMRI & CT of Seaweed Bubble Cells

19F MRI C-arm CT

Comparison Registration Error

Post-mortem/CT 2.83 ± 0.85 mm

CT/MRI 0.32 ± 0.14 mm

How to See Stem Cells in Bubble?How to See Stem Cells in Bubble?

X-ray-visible & “Firefly” Stem Cells

Bio

lum

ines

cenc

e S

igna

l

High

Low

In Vivo Viability of MSCsIn Vivo Viability of MSCs

Blue: NucleusGreen: Dying cell

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

In Vivo Experimental ProtocolFemale New Zealand White Rabbits (n=21)

Harvest

• Endovascular occlusion of the superficial femoral artery with pre-occlusion angiogram

SFA Occlusion

72 hr 2 wk

♀ ♀Liddell et al., JVIR, 2005;16(7):991-8.

In Vivo Experimental Protocol

Harvest

• Six IM injections X-ray capsules • X-ray Fluoroscopic documentation of:

– X-ray Cap location– Collaterals by X-ray Angiogram

XCap

SFA Occlusion

72 hr 2 wk

Female New Zealand White Rabbits (n=21)XCaps + MSCs (n=5) Naked MSCs (n=5) Sham (n=6)XCaps + No MSCs (n=5)

♀

Female New Zealand White Rabbits (n=21)XCaps + MSCs (n=5) Naked MSCs (n=5) Saline Sham (n=6)XCaps + No MSCs (n=5)

In Vivo Experimental Protocol

Harvest

SFA Occlusion

XCap

Histopathology

72 hr 2 wk

Example: Empty XCapExample: Empty XCapPre-occlusion Day 14 Post-occlusion

Example: Xcap with Stem CellsExample: Xcap with Stem CellsPre-occlusion Day 14 Post-occlusion

Efficacy of Stem Cells at Day 14Efficacy of Stem Cells at Day 14Empty Capsule XCap with Stem Cells

TIMI Frame Count @ 14 DaysTIMI Frame Count @ 14 Days

N=16

Tim

e

0

5

10

15

Xcap Blank Xcaps

Tim

e (s

ec)

P<0.002

Naked Cells

P<NSP<0.01

Histopathology – Vessel Density

CD31 Staining for Endothelium

Trimodal Imaging

19F and 1H MRI

c-arm CT

BLI

Conclusions

An X-ray-visible capsule made of clinical grade components was developed that: 1. enabled targeting of injections where most needed

using common interventional radiology X-ray equipment.

2. enabled determination of cell viability in vivo.

3. enhanced cell viability after administration.

4. improved therapeutic effect of creating new blood vessels for treatment of peripheral arterial disease.

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

• Aravind Arepally• Brad Barnett• Jeff Bulte• Gary Huang• Steffi Valdeig• Ron Ouwerkerk• Cliff Weiss

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