Scientists from Michigan State University have developed functional miniature human heart models in the lab. These heart “organoids” are grown from stem cells and are complete with all primary heart cell types with functioning chambers and vascular tissue. The models could help researchers better understand how hearts develop and provide an ethical platform for treating disease.
How did the scientists make these human heart organoids (hHOs)? First, they took samples of skin or blood cells from adults. Then, those samples are reprogramed into stem cells called induced pluripotent stem cells (IPSCs) that can turn into other cell types if needed. IPSCs have previously been used to make mini kidneys, lungs, livers, blood vessels, and brains. Now, hearts are added to that list.
Aitor Aguirre, the study’s senior author, said:
This process allows the stem cells to develop, basically as they would in an embryo, into the various cell types and structures present in the heart. We give the cells the instructions, and they know what they have to do when all the appropriate conditions are met.
The team’s lab-grown mini hearts follow the fetal development of a human heart, offering a new view into that process. The organoids start beating by day six, and they grow into spheres approximately 1 mm (0.4 in) wide, with all significant cardiac cell types and multiple internal chambers by day 15.
This isn’t the first-time researchers have grown hearts; some have even printed them out! Scientists from Massachusetts General Hospital and Harvard Medical School previously grew human hearts from adult skin cells in a lab, while Tel Aviv University researchers “printed” the world’s first 3D vascularized engineered heart using a patient’s own cells and biological materials.
Why grow tiny hearts in the lab? It could solve the shortage problem of hearts the world faces today. More than 25 million people suffer heart failure each year. In the United States, approximately 2,500 of the 4,000 people in line for heart transplants actually receive them. That means almost 50% of the people needing a new heart to keep them alive won’t get it.
That’s not all; the researchers say that growing lab hearts could provide an ethical platform for testing drugs and allow for new treatments of illnesses like congenital heart disease.
The research was published on June 26, 2020, in the preprint server for biology. If your interesting in seeing the heart cells in action, watch the short video below.
