A fundamental limitation to tissue engineering vital organs is the need to create a vascularised support structure for these large 3-D organs. Hence the objectives of this proposal are (1) to devise a modular approach to the fabrication of tissue engineering constructs that are scaleable, with a uniform cell distribution, can accommodate multiple cell types and in which the porosity is created after cell incorporation and (2) To use this modular approach to create a vascularised construct by seeding the construct, containing smooth muscle cells (SMC), with endothelial cells (EC). The prototype to be developed and studied here is based on the porous structure that is created when a column or tube is packed, randomly, with solid objects (here, short cylindrical rods). Cells (eg., SMC) are encapsulated in solid gelatin rods (200 microm diameter, aspect ratio 5 to 10) on to which endothelial cells (eg., HUVEC) can adhere. The gelatin rods are randomly packed into a larger tube and then coated with HUVEC. The interstitial gaps among the rods form interconnected channels, which become lined by the endothelial cells. The resulting endothelial cell lining is expected to enable whole blood to percolate around the rods and through the interstitial channels. We expect good nutrient and oxygen supply (and waste removal) from the encapsulated cells, all of which should be <100 microm away from a 'pseudo-capillary' in this system. In this exploratory research (R21) proposal our focus is on demonstrating the feasibility of the concept and in defining its potential and its limits.
Our specific aims are: (1) Prepare a modular construct using gelatin cylinders encapsulating smooth muscle cells (SMC) or SMC spheroids (2) Seed the construct with endothelial cells before or after assembly of the modules into the construct, in the presence and absence of the SMC. (3) Assess the thrombogenicity of the endothelialised construct in vitro and ex vivo. (4) Assess the phenotype of the two cell types in the context of the construct, when used separately or together. The emphasis is on proof-of-principle studies to support our novel approach to (a) creating porous constructs and (b) generating vascularised structures. However, we note that the endothelialised construct may be subject to unique biomechanical and biochemical cues as a consequence of the un-natural architecture - e.g., there are no arterioles and venules in the construct. This may lead to a unique co-culture model for exploring the cellular interactions of vascular biology.

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21EB001013-02
Application #
6663238
Study Section
Special Emphasis Panel (ZHL1-CSR-O (S1))
Program Officer
Kelley, Christine A
Project Start
2002-09-30
Project End
2005-08-31
Budget Start
2003-09-01
Budget End
2004-08-31
Support Year
2
Fiscal Year
2003
Total Cost
$150,000
Indirect Cost
Name
University of Toronto
Department
Type
DUNS #
259999779
City
Toronto
State
ON
Country
Canada
Zip Code
M5 1-S8
Khan, Omar F; Chamberlain, M Dean; Sefton, Michael V (2012) Toward an in vitro vasculature: differentiation of mesenchymal stromal cells within an endothelial cell-seeded modular construct in a microfluidic flow chamber. Tissue Eng Part A 18:744-56
Khan, Omar F; Sefton, Michael V (2011) Endothelial cell behaviour within a microfluidic mimic of the flow channels of a modular tissue engineered construct. Biomed Microdevices 13:69-87
Gupta, Rohini; Sefton, Michael V (2011) Application of an endothelialized modular construct for islet transplantation in syngeneic and allogeneic immunosuppressed rat models. Tissue Eng Part A 17:2005-15
Chamberlain, M Dean; Butler, Mark J; Ciucurel, Ema C et al. (2010) Fabrication of micro-tissues using modules of collagen gel containing cells. J Vis Exp :
McGuigan, Alison P; Sefton, Michael V (2008) The thrombogenicity of human umbilical vein endothelial cell seeded collagen modules. Biomaterials 29:2453-63
Sosnik, Alejandro; Leung, Brendan M; Sefton, Michael V (2008) Lactoyl-poloxamine/collagen matrix for cell-containing tissue engineering modules. J Biomed Mater Res A 86:339-53
McGuigan, Alison P; Sefton, Michael V (2007) The influence of biomaterials on endothelial cell thrombogenicity. Biomaterials 28:2547-71
Leung, Brendan M; Sefton, Michael V (2007) A modular tissue engineering construct containing smooth muscle cells and endothelial cells. Ann Biomed Eng 35:2039-49
McGuigan, Alison P; Sefton, Michael V (2007) Design and fabrication of sub-mm-sized modules containing encapsulated cells for modular tissue engineering. Tissue Eng 13:1069-78
She, Mingyu; McGuigan, Alison P; Sefton, Michael V (2007) Tissue factor and thrombomodulin expression on endothelial cell-seeded collagen modules for tissue engineering. J Biomed Mater Res A 80:497-504

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