Mechanical Strain and Growth Factors To Stimulate SMC Growth

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Mechanical Strain and Growth Factors To Stimulate
SMC Growth

• Prepared by Seth Hills

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Introduction

• Atherosclerosis
• Costs-Treatments
• Artery Composition

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Our Strategy
Our Goal

• Natural Materials
• Growth Factors
• Cyclic Strain
• Use them together to enhance SMC growth

• Biocompatible tissue engineered vascular graft

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Why are we studying this?

1. They havent been studied together.
2. Growth factors (GFs) stimulate SMC growth.
3. Similar to in vivo
4. Potential additive effects
5. Understand mechanism of atherosclerosis

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Methods

• Tissue Culturing Substrates
• Cell Number vs. Cell DNA
• GF Concentrations vs. Cell Proliferation

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Growth Factors

• TGFß (Transforming Growth Factor Beta)
• PDGF (AA, AB, BB)
• (Platelet Derived Growth Factor)
• FGF (Fibroblast Growth Factor)
• VEGF (Vascular Endothelial Growth Factor)
• IL-2 (Interleukin 2)

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Results
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Future Work

• Mold design for vascular graft
• Factorial Designs
• Design pulsatile flow system

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Vascular Graft Molds
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Factorial Designs

• Mechanical Testing
• Study the effect of cyclic strain, compared to
  static controls, on SMCs with and without GFs.
• Vascular Graft Composition
• Optimize for good mechanical properties
• Cell encapsulation

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Cyclic Strain

• Vacuum provides stretch
• Induces biochemical changes in response to strain
  

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Mechanical Testing
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Vascular Graft Composition
Full Factorial
Design Parameters
Run A B C D Side
1 R
2 - R
3 - - R
4 - - - R
5 - - - - L
6 - - - L
7 - - L
8 - L
9 - - L
10 - - L
11 - - - L
12 - R
13 - - R
14 - - R
15 - R
16 - - - L
Control Factors Levels Levels
Control Factors 2µg/mL (-) 4µg/mL ()
A Collagen    
B Chitosan    
C Elastin    
D Fibrinogen    
Half Factorial
Run A B C D Side
1 R
2 - R
3 - - R
4 - - - R
5 - R
6 - - R
7 - - R
8 - R
for splitting into a half factorial
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Flow System
(Jeng-Jiann Chiu)
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Vascular Graft
(Cummings)
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Methods

• Substrate Study
• Seed cells at 96,000 cells/well in BioFlex 6
  well plates of different substrate along with a
  control.
• When cells are confluent in one of the substrates
  Lyse the cells and perform DNA assay.

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Methods

• Cell Number vs. Cell DNA
• Day 1 Seed cells at different concentrations in
  24 well plate
• Day 2 Lyse cells and perform DNA assay

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Methods

• GF Concentration Study
• Day 1 Seed cells in 24 well plates at 20,000
  cells/well.
• Day 2 Feed cells with quiescent media.
• Day 3 Begin feeding cells with different GF
  concentrations.
• Feed every other day
• Lyse cells when they are confluent in one of the
  concentrations and perform DNA assay.