1. Stimulation of In Vivo Angiogenesis Through Dual Growth Factor Loaded Hyaluronic Acid Hydrogels
Celeste Riley
Mentor: Dr. Robert Peattie
Department of Chemical Engineering

2. Importance Engineered tissues Organ transplants Ischemic Pathologies
(Diabetes)

3. Components of the Project
Preparation of Hydrogels
Surgery on living mouse models
Count formed blood vessels and analyze data

4. Hydrogel Preparation What is a hydrogel? Natural or Synthetic
Biocompatible
Crosslinked to form a gel-like substance
Dehydration

5. Chemical structure of hyaluronic acid
Hydrogel Preparation
What is Hyaluronic Acid?
Glycosaminoglycan
Complexes H20 molecules
Chief component of extracellular matrix
Contributes to cell proliferation and migration
Chemical structure of hyaluronic acid

6. Addition of Growth Factors
What are growth factors?
Diagram of Growth Factor Binding
Signaling proteins
Bind receptors of target cells
Promote differentiation and maturation

7. Addition of Growth Factors
Which Growth Factors?
Model of VEGF
Vascular Endothelial Growth Factor (VEGF)
Angiopoietin 1 (Ang-1)

8. Goal of Project GFs + Make hydrogel from hyaluronic acid
Impregnate hydrogel with growth factors Ang-1 and VEGF
Dehydrate and implant hydrogel into mouse ear
Determine if implant, loaded with growth factors, stimulates angiogenesis
GFs +

9. Project Setup Conditions to consider Spontaneous Growth
Original Vessels
Individual combinations: control cases (chart)

10. Treatment Cases 6 animals per treatment group Treatment 1 2 3 4 5 6 78
HA gel - +
VEGF
Ang-1

11. Determining Blood Vessel Growth
Thin-section both surgical and contralateral ear
Count blood vessels under 400X magnification
Contralateral Ear

12. Data Analysis Define a statistical index to account for
What do we want to measure?
How do we measure it?
Define a statistical index to account for
effect of sham surgery
number of vessels present before surgery
Additional vessels due only to the particular surgical treatment

13. Neovascularization Index
NI = (treatment-CL) – (sham-CL) mean CL
(treatment-CL) = average # of additional blood vessels in the implanted ear of treatment group
(sham-CL) = average # of additional vessels due to the surgical procedure itself
mean CL = average vessel count in all contralateral ears: effectiveness measure

14. Results Treatment 7 day NI 14 day NI - 0.12 1.80 0.95 1.30 2.97 6.74
Sham -
HA gel only
0.12
1.80
VEGF only
0.95
1.30
Ang-1 only
Ang-1 + VEGF
HA gel + Ang-1
HA gel + VEGF
2.97
6.74
HA gel + Ang-1 + VEGF

15. Conclusion Currently, data collection is still ongoing
When calculated, compare NI of experimental case to NIs of control cases
At this point, no definite conclusion can be drawn about the effect of Ang-1 and VEGF delivered through HA hydrogel on angiogenesis

16. Hughes Medical Institute
Acknowledgments
Dr. Robert Peattie
Dr. Kevin Ahern
Howard
Hughes Medical Institute
Co-researcher
Peter Fuegy