CHEMICAL AND PHYSICAL REGULATION OF STEM CELLS AND PROGENITOR CELLS: POTENTIAL FOR CARDIOVASCULAR TISSUE ENGINEERING (REVIEW) NGAN F. HUANG, RANDALL J. LEE, SONG LI By Deepika Chitturi BIOE 506 Spring 2009
Dec 13, 2015
CHEMICAL AND PHYSICAL REGULATION OF STEM CELLS AND PROGENITOR CELLS: POTENTIAL FOR CARDIOVASCULAR TISSUE ENGINEERING (REVIEW)
NGAN F. HUANG, RANDALL J. LEE, SONG LI
By Deepika Chitturi
BIOE 506
Spring 2009
WHY CARDIOVASCULAR TISSUE ENGINEERING? Leading Cause of Mortality
(every 34 sec) Expensive ($250 billion) Myocardial Infarction (MI aka
heart-attacks)
Coronary Artery Occlusion Cardiomyocyte Cell Death Non-generation Formation of Scar Tissue Dilation of Chamber Cavities Aneurysmal Thinning of Walls
REDUCED PUMPING CAPACITY
Driving Force: Shortage of Donors
POTENTIAL STEM & PROGENITOR CELLS
MSCs: Mesenchymal Stem Cells
HSCs: Hematopoietic Stem Cells
EPCs: Endothelial Precursor Cells
ESCs: Embryonic Stem Cells
Skeletal Myoblasts
Resident Cardiac Stem Cells
CARDIOVASCULAR TISSUE ENGINEERING (I)
Cell Source
Embryonic Stem Cells Adult Stem Cells
Soluble Chemical Factors
VEGF (ESCs, HSCs, EPCs) TGF-β (ESCs, MSCs, HSCs,
EPCs) BMP (ESCs) 5-azacytidine (MSCs) FGF (ESCs, HSCs, EPCs) IGF (HSCs, EPCs)
CARDIOVASCULAR TISSUE ENGINEERING (II) Extracellular Matrix
Natural Polymers
Matrigel: In vivo injection for MI, ESC differentiation Collagen: In vivo injection for MI, Vascular grafts Hyalinuric Acid: Vascular grafts Alginate: ESC differentiation Fibrin: In vivo injection for MI, Vascular conduits Decellularized Vessel: Vascular conduits
Synthetic Polymers
Poly-L-lactic Acid (PLLA): ESC differentiation Poly-lactic-co-glycolic acid (PLGA): ESC differentiation Polyglycotic Acid (PGA): Vascular grafts Peptide Nanofibers: In vivo injection for MI Poly-diol-citrates and Poly-glycerol-sebacate: General tissue
engineering
EXTRACELLULAR MATRIX
Dr. Vasif Harsirci- Middle East Technical University (Biomedical Unit)
Matrigel Angiogenesis PLLA Angiogenesis
Effects of Cordyceps militaris extract on angiogenesis and tumor growth1 Hwa-seung YOO, Jang-woo SHIN2, Jung-hyo CHO, Chang-gue SON, Yeon-weol LEE, Sang-yong PARK3, Chong-kwan CHO4 Department of East-West Cancer Center, College of Oriental Medicine, Daejeon University, Daejeon 301-724;
ROLE OF MATRIX MATERIALS FOR STRUCTURAL SUPPORT hESCs cultured in porous PLGA/PLLA scaffolds coated
with Matrigel or Fibronectin vs. Matrigel alone or fibronectin-coated dishes (Levenberg et al)
3-D polymer structure promoted differentiation (neural tissue, cartilage, liver and blood vessels)
Formation of 3-D blood vessels Fibronectin-coated dishes:
Failure to organize into 3-D structure Matrigel:
Organization into 3-D structure No cell differentiation
Conclusion:
Large inter-connected pores: cell colonization Pores smaller than 100 nm: limit diffusion of nutrients and gases 3-D: great surface area, higher expression of integrins
ROLE OF MATRIX TOPOGRAPHY AND RIGIDITY Topography: Cell Organization, alignment and
differentiation
Nano-scale and micro-scale matrix topography affects organization and differentiation of stem cells
hMSCs undergo skeletal reorganization and orient themselves in the direction of microgrooves and nano-fibers (Patel et al)
Stiffness/Rigidity: Cells tend to migrate toward more-rigid surfaces and cells on soft matrix have a low rate of DNA synthesis and growth (Engler et al)
Assembly of focal adhesions and contractile cytoskeleton structure depend on rigidity
CARDIOVASCULAR TISSUE ENGINEERING MODELS
In vitro differentiation method: engineering constructs with structural and functional properties as native tissues before transplantation
In situ method: relies on host environment to remodel the chemical and physical environment for cell growth and function
Ex vivo approach: excision of native tissues and remodeling them in culture
CARDIOVASCULAR TISSUE ENGINEERING PROPOSED MODELS
Injectable Stem Cells and Progenitor Cells for in situ cardiac tissue engineering
Vascular Conduits
INJECTABLE STEM CELLS AND PROGENITOR CELLS FOR IN SITU CARDIAC TISSUE ENGINEERING
Delivery modes for myocardial constructs:
Cardiac patching
Cell Injection
Cell-polymer injection
Less invasive than solid scaffolds Adopt shape and form of host environment Delivery vehicles (with cells and GFs) Polymers: Collagen I, Matrigel, Fibrin, Alginate and
Peptide Nanofibers
INJECTABLE DELIVERY OF POLYMERS
Collagen I, Matrigel and Fibrin
Higher capillary density than saline control treatment Migration of vascular cells into infarcted region for
neovascularization
Fibrin + MSCs (Huang et al)
Promotes angiogenesis
ESCs + Matrigel (Kofidis et al)
Greater improvements in contractility after 2 weeks
Rat bone marrow mononuclear cells (MNCs) + Fibrin (Ryu et al)
Enhanced neovascularization Development of larger vessels Extensive tissue regeneration Graft survival: 8 weeks
TREATMENT USING STEM AND PROGENITOR CELLS ALONE TGF-β-treated CD117+ rat MNCs (Li et al)
Differentiation into myogenic lineage Enhanced vascular density
Retrovirally transduced Akt1-overexpressing MSCs (Mangi et al, Laflamme et al)
Reduced intramyocardial inflammation 80% of lost myocardial volume regeneration Normal systolic and diastolic functions restoration
Cardiac enriched hESCs in athymic rats (Laflamme et al)
Cardiomyocyte growth No teratomas 7-fold increase in graft size in 4 weeks Potential regeneration of human myocardium in rat heart
VASCULAR CONDUITS
Goal: To create functional conduit as a bypass graft (small, non-thrombogenic, native mechanical properties)
Limitations to vein grafts: Availability 35% 10-year failure
Synthetic Vascular Grafts: Poly-ethylene-terephthalate Expanded poly-
tetrafluoroethylene Polyurethane Limitation:
Inside diameter larger than 5 mm Frequent thrombosis and
occlusions in smaller grafts
VASCULAR CONDUITS—PROPOSED MODELS ECs + SMCs in a tubular PGA porous scaffold (Niklason et
al)
In vivo implantation: patent for 2 weeks; development of histological features consistent with vascular structures
EPC-seeded grafts (Kaushal et al)
Remained patent for more than 130 days Acellular control grafts occluded in 15 days Vessel-like characteristics: contractility and nitric-oxide mediated
vascular relaxation
EPCs derived from umbilical cord blood using 3D porous polyurethane tubular scaffolds in a biomimetic flow system (Schmidt et al)
In 12 days, EPCs lined lumen of VGs and formed endothelial morphology
VASCULAR CONDUITS—PROPOSED MODELS
MSC seeded nanofibrous vascular grafts (Hashi et al)
Patent for at least 8 weeks Synthesis and organization of collagen and
elastin EC monolayer formed on lumen surfaces SMCs were recruited and formed