A major aspect of regenerative medicine is to develop tissue engineering techniques that allow a defective organ or tissue to be replaced with a normally functioning substitute. One key challenge of creating engineered tissue, however, is the lack of a perfused microvascular network which serves to supply oxygen and nutrients to the tissue. The endothelial cells forming this vascular network not only serve as pipes carrying blood through the tissue, they also play a critical role in the development and differentiation of cells comprising the tissue. This is particularly evident in the developing pancreas.
The researchers have previously demonstrated how the shear stress created by blood flow through the vessels of a developing tissue serves as an instructive signal to the endothelium that is then transmitted to the adjacent cells to control cell differentiation in the developing tissue. Therefore in order to develop a bioengineered tissue, it is necessary to create a system consisting of interconnected capillaries with open lumens that can support blood flow through the tissue in order to provide nutrients as well as inform the differentiation of stem cells and progenitor cells.
In this study, the researchers seek to overcome this challenge and create a functional tissue with a perfused vascular network that can be implanted into a patient to restore the lost function of a tissue. They will accomplish this using novel 3-D tissue bio-printing technology, which uses utilizes technology similar to an ink jet printer to lay down sequential layers of extracellular matrix and cells. The proposed system will result in two adjacent 3-D vascular channels lined with endothelial cells that are perfused separately and are connected by a series of microvessels that allow flow from one vascular channel to another.