Follow Canada Immigration follow Canada Technology: Researchers at the Institute of Biomaterials and Biomedical Engineering (IBBME) at the University of Toronto in Canada, in collaboration with the McEwen Centre for Regenerative Medicine, have for the first time determined the optimal structure and cell ratio related to cardiac function. This discovery has led the team to another study: designing and manufacturing the first living three-dimensional human arrhythmic tissue to date. This also marks the first time researchers have attempted to determine a precise "recipe" of cell types and ratios that can produce highly functional cardiac tissue. The relevant paper was published in the recent issue of the U.S. journal "Proceedings of the National Academy of Sciences".
"The heart is not made of just one type of cell." Nimalan Thavandiran, the paper's lead author and an IBBME doctoral student, said that previously, when culturing cardiac tissue, scientists did not know how to mix different types of cells to allow them to develop into cardiac structures and gradually mature into natural human hearts.
Thavandiran separated different cell types derived from human pluripotent stem cells and then precisely "assembled" them back together. By using a scoring metric to link them to cardiac functions such as contraction, electrical activity, and cell alignment, a "recipe" formula was formed, which can be used to manufacture highly functional cardiac tissue. "The ratio of cells is critical," Thavandiran said. "We found that a ratio of 25% cardiac fibroblasts (skin-like cells) to 75% cardiomyocytes (heart cells) works better." The carefully mixed cell ratio simulates the structure of human heart tissue, growing into three-dimensional "wires".
After finding the appropriate cardiac cell composition, the researchers designed the first three-dimensional arrhythmic tissue model. They applied electrical pulses to the tissue, "hitting" the irregularly beating tissue and turning it into a state of regular contraction. Arrhythmia refers to the disruption of the heart's electrical impulses, preventing it from contracting and pumping blood effectively; millions of people suffer from arrhythmia every year. "Now we can combine this composition with electrical and mechanical stimulation to obtain a true bio-simulation system for cardiac research," said Milica Radisic, the paper's corresponding author.
"An exciting result of the study is that we can cultivate human cardiac micro-tissues to test the response of healthy and diseased human hearts to drugs," said Peter Zandstra, the paper's corresponding author and the Canada Research Chair in Stem Cell Bioengineering at IBBME and the McEwen Centre for Regenerative Medicine.
Because human heart cells are difficult to grow, creating highly efficient functional cardiac tissue using human stem cells is a matter of great concern to scientists. There is also an urgent need for highly functional cardiac tissue in drug screening. Currently, the research team is working with the Centre for Commercialization of Regenerative Medicine (CCRM) to promote their tissue model platform.
