Cardiac Fibroblasts as a Support for Endothelial Cell Sprout Formation in Engineered Cardiac Tissue.
tissue engineering offers a promising approach to regenerating post-MI myocardial
tissue; however, a primary impediment in tissue engineering lies in the inability to
adequately vascularize a tissue scaffold. Cardiac tissue constructs require a closer
proximity to a nutrient and blood supply than many other tissues due to the higher
metabolic demands of myocardium, further d... read moreecreasing the required distance to a capillary
bed. It is known that endothelial cells (ECs) require a support cell to form mature
patent lumens both in vivo and in vitro, and it has been demonstrated that pericytes,
vascular smooth muscle cells and mesenchymal stem cells (MSCs) are able to support the
formation of mature tubules/vessels. Cardiac fibroblasts (CFs) provide important
electrical and mechanical components to the myocardial tissue and are present in the
native cardiac cell population, but to date have not been sufficiently studied for their
role in angiogenesis in heart. Three different approaches were used to study the ability
of CFs to aid in the formation of EC sprouts: 1) varying the co-culture ratio of
neonatal CFs to ECs to best match the in vivo conditions, while comparing the results to
EC sprout formation in MSC co-cultures, 2) studying the differences of EC proliferation
and sprout formation in co-culture with CFs at different developmental life points:
fetal, neonatal and adult and 3) the use of a decellularized vessel as a central conduit
for angiogensis in a fibrin construct. As a model of myocardial tissue, we co-cultured
different concentrations of various cell types in fibrin hemispheres in appropriate
combinations of their specific media to determine the optimal sprout formation through
DNA analysis, flow cytometry and immunohistology (IH). Our hypothesis was that cardiac
fibroblasts can support endothelial cell sprout formation as well or better than
mesenchymal stem cells, which are considered to be a "gold standard" for the
stabilization of EC sprouts in engineered tissues. Our results indicated that ECs tended
to form longer and more numerous sprouts in culture with neonatal CFs, but formed more
multi-cellular sprouts in culture with MSCs, which is more indicative of the in vivo
process. Additionally, we found that EC proliferation was best when cultured with
neonatal and adult CFs over the proliferation rate with fetal CFs. In summary, cardiac
fibroblasts are able to provide a support for the formation of endothelial cell sprouts
and could aid in the eventual vascularization of a cardiac tissue
Thesis (M.S.)--Tufts University, 2012.
Submitted to the Dept. of Biomedical Engineering.
Advisor: Lauren Black III.
Committee: David Kaplan, and Ira Herman.
Keyword: Biomedical engineering.read less