According to an article [wiley.com] in the journal Advanced Science, researchers at Tel Aviv University were able to create a small 3d Printed heart that included blood vessels [technologyreview.com] out of human tissue.
Until now, researchers have only been able to print simple tissues lacking blood vessels, so a 3D, fully vascularized engineered heart is a step in the right direction.
The process consists of taking a sample of abdominal fat tissue, reprogramming the cells to become induced pluripotent stem cells (iPSCs), differentiating these into cardiac muscle cells and blood vessel cells, and combining them with hydrogels to form structures for the cells to proliferate on.
Heart disease causes one in four deaths in the US (about 610,000 people a year), and there’s a shortage of heart donors for transplants, so 3D-printed hearts could help solve a major issue
As a next step the team plans to culture, print, and transplant similar hearts into animals. Significant challenges still remain, such as the efficient cultivation of the stem cells to gain the large quantity needed to engineer full sized organs and improvement of the blood vessel network demonstrated; the team indicates we are many, many years from from doing this for humans.