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@ARTICLE{Tiper:277741,
author = {Tiper, Yekaterina and Xie, Zhuoye and Hofemeier, Arne and
Lad, Heta and Luber, Mattias and Krawetz, Roman and Betz,
Timo and Zimmermann, Wolfram-Hubertus and Morton, Aaron B
and Segal, Steven S and Gilbert, Penney M},
title = {{O}ptimizing electrical field stimulation parameters
reveals the maximum contractile function of human skeletal
muscle microtissues.},
journal = {American journal of physiology / Cell physiology},
volume = {328},
number = {4},
issn = {0363-6143},
address = {Bethesda, Md.},
publisher = {American Physiological Society},
reportid = {DZNE-2025-00462},
pages = {C1160 - C1176},
year = {2025},
abstract = {Skeletal muscle microtissues are engineered to develop
therapies for restoring muscle function in patients.
However, optimal electrical field stimulation (EFS)
parameters to evaluate the function of muscle microtissues
remain unestablished. This study reports a protocol to
optimize EFS parameters for eliciting contractile force of
muscle microtissues cultured in micropost platforms. Muscle
microtissues were produced across an opposing pair of
microposts in polydimethylsiloxane and polymethyl
methacrylate culture platforms using primary, immortalized,
and induced pluripotent stem cell-derived myoblasts. In
response to EFS between needle electrodes, contraction
deflects microposts proportional to developed force. At 5 V,
pulse durations used for native muscle (0.1-1 ms) failed to
elicit contraction of microtissues; durations reported for
engineered muscle (5-10 ms) failed to elicit peak force.
Instead, pulse durations of 20-80 ms were required to elicit
peak twitch force across microtissues derived from five
myoblast lines. Similarly, although peak tetanic force
occurs at 20-50 Hz for native human muscles, it varied
across microtissues depending on the cell line type, ranging
from 7 to 60 Hz. A new parameter, the dynamic oscillation of
force, captured trends during rhythmic contractions, whereas
quantifying the duration-at-peak force provides an extended
kinetics parameter. Our findings indicate that muscle
microtissues have cell line type-specific contractile
properties, yet all contract and relax more slowly than
native muscle, implicating underdeveloped
excitation-contraction coupling. Failure to optimize EFS
parameters can mask the functional potential of muscle
microtissues by underestimating force production. Optimizing
and reporting EFS parameters and metrics is necessary to
leverage muscle microtissues for advancing skeletal muscle
therapies.NEW $\&$ NOTEWORTHY Electrical field stimulation
(EFS) parameters remain to be standardized for engineered
skeletal muscle. Herein, we report a protocol for defining
EFS parameters that elicit the maximal contractile force of
muscle microtissues cultivated in micropost devices and
highlight the value of developing appropriate metrics. The
dynamic oscillation of force and duration-at-peak force are
introduced as novel metrics of contraction kinetics.},
keywords = {Humans / Muscle Contraction: physiology / Electric
Stimulation: methods / Muscle, Skeletal: physiology /
Myoblasts: physiology / Myoblasts: cytology / Tissue
Engineering: methods / Induced Pluripotent Stem Cells:
physiology / Induced Pluripotent Stem Cells: cytology /
Cells, Cultured / Cell Line / contractile function (Other) /
electrical field stimulation (Other) / engineered skeletal
muscle (Other) / induced pluripotent stem cells (Other) /
micropost platform (Other)},
cin = {AG Fischer},
ddc = {000},
cid = {I:(DE-2719)1410002},
pnm = {352 - Disease Mechanisms (POF4-352)},
pid = {G:(DE-HGF)POF4-352},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:40019026},
doi = {10.1152/ajpcell.00308.2024},
url = {https://pub.dzne.de/record/277741},
}