TY  - JOUR
AU  - Tiper, Yekaterina
AU  - Xie, Zhuoye
AU  - Hofemeier, Arne
AU  - Lad, Heta
AU  - Luber, Mattias
AU  - Krawetz, Roman
AU  - Betz, Timo
AU  - Zimmermann, Wolfram-Hubertus
AU  - Morton, Aaron B
AU  - Segal, Steven S
AU  - Gilbert, Penney M
TI  - Optimizing electrical field stimulation parameters reveals the maximum contractile function of human skeletal muscle microtissues.
JO  - American journal of physiology / Cell physiology
VL  - 328
IS  - 4
SN  - 0363-6143
CY  - Bethesda, Md.
PB  - American Physiological Society
M1  - DZNE-2025-00462
SP  - C1160 - C1176
PY  - 2025
AB  - 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 </td><td width="150">
AB  -  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.
KW  - Humans
KW  - Muscle Contraction: physiology
KW  - Electric Stimulation: methods
KW  - Muscle, Skeletal: physiology
KW  - Myoblasts: physiology
KW  - Myoblasts: cytology
KW  - Tissue Engineering: methods
KW  - Induced Pluripotent Stem Cells: physiology
KW  - Induced Pluripotent Stem Cells: cytology
KW  - Cells, Cultured
KW  - Cell Line
KW  - contractile function (Other)
KW  - electrical field stimulation (Other)
KW  - engineered skeletal muscle (Other)
KW  - induced pluripotent stem cells (Other)
KW  - micropost platform (Other)
LB  - PUB:(DE-HGF)16
C6  - pmid:40019026
DO  - DOI:10.1152/ajpcell.00308.2024
UR  - https://pub.dzne.de/record/277741
ER  -