There are many heart diseases and genetic disorders that need more research. An invention called a cardioid will help with the research. In a laboratory in Vienna, they used stem cells to create thousands of tiny structures that are similar to a real heart. The goal of these small hearts is primarily to research the development of the heart and heart disease. Individual cardioids are not larger than sesame seeds, but they are still hollow and beating. In the future, they could be used in research instead of hearts from laboratory animals.
How are cardioids made?
These structures are very different from other artificial hearts. Jiná lab-grown hearts are created by using outside scaffolds and cells that they moved around — like constructing a wall out of bricks.
A detailed description of Cardioids is given in the Cell journal. How is cardioids actually formed? Scientists introduced the stem cells to a series of chemicals that play important roles in heart development. The cardioids grow from bundles of stem cells into millimeter-wide water balloons in just 1 week. Cardioids usually resemble the left ventricle – the largest ventricle in the heart.
“You see the cells changing shape [while they grow] and it’s really incredible, but it’s on another level when they actually do something,” says Nora Papai, a biologist at the Austrian Academy of Sciences’ Institute of Molecular Biology and co-author of the study. “They start twitching at day five or so, and at day seven you see this nice pace of beating.”
A cardioid is a type of organoid. Organoid is a miniature version of an organ grown in the lab for use in research. In the past, various types of organoids have been created, but so far none have been created that is created only from stem cells and chemical signals.
The difference between a cardioid and a real heart
Cardioids aren’t connected to a circulatory system and unlike hearts, which have four chambers, cardioids only have the one chamber and this chamber is filled with liquid. Each cardioid begins as a cluster of pluripotent stem cells. Such cells can transform into any cell in the human body based on signals from the environment. Six chemicals important for heart development were used for the research. Some previous attempts were unsuccessful because they used few factors, but only when all six factors were used did the experiment succeed. Three-dimensional space was required for cell development so that the cells had enough space to form a balloon-like shape.
Heart disease research
Cardioids have begun to be used to test the heart’s responses to various types of injuries, genetic mutations and diseases that affect both children and adults.
“There’s no way for us to look at this in the human embryo at that stage because women don’t even know that they’re pregnant by that stage,” says Mendjan. The cardioid mimics the appearance of an embryonic heart after about the first month of development. So cardioids may be able to help with the study of defects like hypoplastic left heart syndrome, which appears early in development and is deadly without an invasive surgery.
Examination of a heart attack
Many people die of heart attacks every year. Even in this case, cardioids can be beneficial because they allow you to simulate a heart attack in a controlled environment.
“During a heart attack, almost one billion cells die, but they don’t just disappear,” says Papai. To mimic the effect of many dead cells left behind on the cardioids, Papai and colleagues used a thin metal rod, about the size of the pin used to remove SIM cards from smartphones, that they dipped in liquid nitrogen to reach minus-320 degrees Fahrenheit.
“When you hold it into the cells, that area immediately dies off due to the very cold temperature. But when the cells die, they don’t disappear,” says Papai. The cells stay behind on the cardioid, which then starts to recover.
Different types of cardioids
Researchers have created various types of cardioids, some resembling embryonic hearts, others resembling adult hearts. Because some cardioids have been shown to regenerate, they may be used to find a suitable treatment for people after a heart attack.
“Remarkably, Mendjan and colleagues overcome a major hurdle in the field to generate self-organizing human cardioids… by harnessing the normal rules of heart development,” writes Massachusetts Institute of Technology biological engineer Laurie Boyer, who studies the genes involved in heart development and was not involved in the new research, in an email.
The research team has patented its cardioids and believes that they can be used to find suitable treatments for people with various heart diseases.
“This is now a bit creepy, but the amazing thing is that you can stimulate them to beat faster,” says Mendjan. “If you do these tests and you add, for example, adrenaline to them, all of them just wake up and then start beating very fast. And this is the same drug you would use to get a patient out of a heart attack.”
This is very important research that will help take another big step forward in medicine.
Source & credit:
Courtesy of the Mendjan Lab
https://www.cell.com/cell/fulltext/S0092-8674(21)00537-7
https://www.smithsonianmag.com/science-nature/scientists-use-stem-cells-invent-self-assembling-miniature-heart-chamber-180977778/
