Researchers create 3D model of heart tissue

Researchers from the University of Toronto have this week created the first three dimensional model of arrhythmic cardiac tissue (heart tissue with an uneven heartbeat) by understanding the optimum cell types and structure needed to create heart tissue. The study was published this week in the Proceedings of the National Academy of Science.

To test drugs for heart disease, scientists need heart cells that behave as they do in the body. However, these are incredibly difficult to obtain. A heart is made of several different types of cell and this study is the first time scientists have tried to formulate the precise ratio and arrangements of cell types in the creation of realistic cardiac tissue. The team achieved this by using human pluripotent stem cells (stem cells that can differentiate into many different types of cell) that they induced to become different types of heart cell. They then split the different types of heart cell and recombined them in different ratios. The researchers developed metrics for different heart functions: contraction, electrical activity and cell alignment and therefore were able to engineer functional heart tissue.

The team found that “a mixture of 25% cardiac fibroblasts (skin-like cells) to 75% cardiomyocytes (heart cells) worked best” according to PhD student Nimalan Thavandiran. This ratio of cells was then grown into cardiac microtissues, that they call cardiac microwires. This allowed them to control the growth so it became a similar shape to a functional heart. The researchers then went one step further and created the first 3D heart tissue model of arrhythmia. Arrhythmia occurs when the heart can’t contract properly because the feedback of electrical pulses are interrupted, leading to an uneven heartbeat. The team then sent an electrical pulse into this arrhythmic tissue and the cells started beating rhythmically. The next step is to bring this model to the commercial market for use in drug research

Read more at : http://medicine.utoronto.ca/news/what-composes-human-heart-u-t-researchers-crunch-numbers