AUTHOR=Hansen Katrina J. , Laflamme Michael A. , Gaudette Glenn R. 

TITLE=Development of a Contractile Cardiac Fiber From Pluripotent Stem Cell Derived Cardiomyocytes

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 5 - 2018

YEAR=2018

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2018.00052

DOI=10.3389/fcvm.2018.00052

ISSN=2297-055X

ABSTRACT=Stem cell therapy has the potential to regenerate cardiac function after myocardial infarction. In this study, we sought to examine if  fibrin microthread technology could be leveraged to develop a contractile fiber from human pluripotent stem cell derived cardiomyocytes (hPS-CM). hPS-CM seeded onto fibrin microthreads were able to adhere to the microthread and began to contract seven days after initial seeding. A digital speckle tracking algorithm was applied to high speed video data (>60fps) to determine contraction behaviour including beat frequency, average and maximum contractile  strain, and the principal angle of contraction of hPS-CM contracting on the microthreads over 21 days. At day 7, cells seeded on tissue culture plastic beat at 0.83±0.25beats/sec with an average contractile strain of 4.23±0.23%, which was significantly different from a beat frequency of 1.11±0.45beats/sec and an average contractile strain of 3.08±0.19% at day 21 (n=18, p<0.05). hPS-CM seeded on microthreads beat at 0.84±0.15beats/sec with an average contractile strain of 3.56±0.22%, which significantly increased to 1.03±0.19beats/sec and 4.47±0.29%, respectively, at 21 days (n=18, p<0.05). At day 7, 27% of the cells had a principle angle of contraction within 20 degrees of the microthread, whereas at day 21, 65% of hPS-CM were contracting within 20 degrees of the microthread (n=17). Utilizing high speed calcium transient data (>300fps) of Fluo-4AM loaded hPS-CM seeded microthreads, conduction velocities significantly increased from 3.69±1.76cm/s at day 7 to 24.26±8.42cm/s at day 21 (n=5-6, p<0.05). hPS-CM seeded microthreads exhibited positive expression for connexin 43, a gap junction protein, between cells. These data suggest that the fibrin microthread is a suitable scaffold for hPS-CM attachment and contraction. In addition, extended culture allows cells to contract in the direction of the thread, suggesting alignment of the cells in the microthread direction.