Washington: Researchers, who have for the first time identified the optimal structure and cell ratio associated with heart function, have also designed the first-ever three-dimensional arrhythmia tissue model.
Arrhythmia is a condition in which the feedback of electrical pulses of the heart is interrupted, leaving the heart unable to contract and pump blood effectively.
The study by researchers at the University of Toronto's Institute of Biomaterials and Biomedical Engineering (IBBME) and the McEwen Centre for Regenerative Medicine marks the first time that researchers have tried to define and formulate the precise type and ratio of cell types that produce highly functional cardiac tissue.
Until now, scientists have not known how to mix different cell types in engineered heart tissue in such a way that the tissue achieves the composition and maturity level of the native human heart.
However, Nimalan Thavandiran, first author of the study, solved this mystery by methodically separating out different cell types derived from human pluripotent stem cells and precisely mixing them back together.
Using scoring metrics associated with functional hearts- contraction, electrical activity and cell alignment- Thavandiran was able to develop a formula for engineering highly functional heart tissue.
The composition of the cells is vital," stated Thavandiran. "We discovered that a mixture of 25 percent cardiac fibroblasts (skin-like cells) to 75 percent cardiomyoctes (heart cells) worked best."
Professor Peter Zandstra, corresponding author of the study, said that an exciting result of the study was their ability to miniaturize the tissues into human heart micro-tissues that can be used to measure normal and diseased human heart responses to drugs.
From discovering the right composition of heart cells, the researchers next designed the first-ever three-dimensional arrhythmia tissue model.
With the right cellular composition, though, the researchers were able to engineer the circular tissue model associated with arrhythmia. The team then applied electrical pulses to the arrhythmic tissues, 'zapping' the irregularly beating tissue into a state of regular contractions.
The study is published in journal PNAS.
