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Tissue engineering aims to generate or replace damaged or failed tissues with viable and functional de novo tissues that integrate with the host system. This goal remains challenging. The very early approach to engineer tissues published by Langer and Vacanti in Science in 1993 is to seed cells in three dimensional (3D) scaffolds, then transplant this cell-scaffold device into the body. While a promising concept in principle, in practice this approach has been subject to the basic constraints imposed by the requirements for transport of oxygen and other nutrients to the growing cells. Hence, until now, the successes of tissue engineering have been restricted to relatively thin and/or avascular structures such as skin and cartilage.
Some recent clinical successes include bladder and trachea – again, thin structures where post implantation neovascularisation from the host is sufficient to meet the implant’s demand for oxygen and nutrients. For thick and metabolic tissues, however, a fully connected and functional blood vessel network must be created. Mesenchymal stem cells (MSCs) are bone marrow derived, self-renewing and multipotent progenitors. MSCs have been shown to be capable of differentiating into multiple cell types including adipocytes, chondrocytes, osteocytes, hepatocytes, cardiomyocytes and neurons. In recent years, the culture of MSCs with endothelial cells has been proposed as an effective tool to address rapid vascularisation of tissue-engineered grafts. For example, the culture of MSCs together with dermal microvascular endothelial cells improved osteogenesis and vascularisation of MSCs.
This project will form part of a larger effort to grow vascularised tissue in vitro, and will focus on investigating the interactions of human microvascular endothelial cells (hMVECs) and MSCs in a 3D environment. Briefly, hMVECs will be isolated from human dermis. The isolated cells will be co-cultured with human MSCs in 3D biodegradable polymer scaffolds.
The approaches are:
- fabrication of polylactide (PLA) scaffolds using thermally induced phase separation which is a well developed technique
- investigation of the method of isolation and expansion of microvascular endothelial cells from human skin
- human MSCs will be co-cultured with the obtained microvascular endothelial cells in PLA scaffolds for certain period of time.
- observation of cell morphology under Confocal microscope. Endothelial cell marker will be identified. Cell proliferation within the 3D scaffold will be characterised using various assays.
- R. Langer and J. P. Vacanti (1993), Science, 260: 920-926.
- Kaigler, D. etc (2005) Endothelial cell modulation of bone marrow stromal cell osteogenic potential. FASEB J 19:665-692.