The promise of engineered human organs has been held out for some years. The idea is that rather than relying on an otherwise healthy donor, failing livers, kidneys, hearts and lungs could be built to order in a lab and implanted into a patient. The reality, however, has proved more difficult as human organs are complex structures with many working parts.
A potential breakthrough has come from York University in Toronto, Canada, where Prof Mohammed Yousaf has led a team that has, for the first time, joined together three types of cell found in the heart that contract in unison to make tissue that beats like a living heart. Moreover, the team achieved this feat without using a scaffolding structure to support the tissue as it forms.
Yousaf has developed a substance called "ViaGlue", based on liposomes that have the ability to self-assemble, which can be attached to living cells and link them together, almost like Velcro.
He has formed a company called OrganoLinx to commercialise this discovery, and has demonstrated a range of "tissue prototypes" in a series of papers that use ViaGlue to make tissues that have the properties of liver, kidneys, skin and lungs.
His latest work has involved using the material to join together contractile cardiac muscle cells, connective tissue cells and vascular cells to make heart tissue. Moreover, use of ViaGlue meant that the project did not have to construct a scaffold out of gelatin, collagen, or synthetic polymer to support the cells as they grow.
Youssaf explained that this can cause problems with ensuring the cells have a good oxygen supply and can cause biocompatibility problems when the organs are implanted, and also reduces the cell density in the resulting structure. The problem with previous attempts to build heart tissue has come with the difficulty of making all the types of cell beat together, as they do in the heart
"Making in vitro 3D cardiac tissue has long presented a challenge to scientists because of the high density of cells and muscularity of the heart," said one of Yousaf’s team, graduate student Dmitry Rogozhnikov. “For 2D or 3D cardiac tissue to be functional it needs the same high cellular density and the cells must be in contact to facilitate synchronised beating.”
The team explained its research in a paper in Nature Scientific Reports. The tissue was created as a millimetre scale, but Yousaf is confident that he could be scaled up.
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