Scientists at the University of Toronto's Institute of Biomaterials & Biomedical Engineering (IBBME) and the McEwen Centre for Regenerative Medicine have made a breakthrough and created the first-ever living, three-dimensional human arrhythmic tissue.
Extensive research led them to successfully infer the exact type and ratio of cell types which can produce highly functional cardiac tissue.
Electrical pulses were applied to the arrhythmic tissues to get the irregularly beating tissue into a state of regular contractions.
"Hearts are not just composed of one type of cell," said fourth-year IBBME PhD student Nimalan Thavandiran, who is the first author of the study.
Scientists have not been able to combine the many cell types in engineered heart tissue in a manner that the tissue achieves the composition and maturity level of the native human heart.
Scientists cracked the problem by systematically sorting out different cell types taken from human pluripotent stem cells and mixing them together in a precise way.
"The composition of the cells is vital. We discovered that a mixture of 25 per cent cardiac fibroblasts (skin-like cells) to 75 per cent cardiomyoctes (heart cells) worked best," said Thavandiran.
"The carefully composed cell ratios were then grown in three-dimensional "wires" that mimic the structure of human heart tissue.An exciting result of our study is our ability to miniaturise the tissues into human heart micro-tissues that can be used to measure normal and diseased human heart responses to drugs," said Professor Peter Zandstra, who is part of the team that conducted the study.