Automated analysis of contractile force and Ca2+ transients in engineered heart tissue

TY - JOUR

T1 - Automated analysis of contractile force and Ca2+ transients in engineered heart tissue

AU - Stoehr, Andrea

AU - Neuber, Christiane

AU - Baldauf, Christina

AU - Vollert, Ingra

AU - Friedrich, Felix W

AU - Flenner, Frederik

AU - Carrier, Lucie

AU - Eder, Alexandra

AU - Schaaf, Sebastian

AU - Hirt, Marc N

AU - Aksehirlioglu, Bülent

AU - Tong, Carl W

AU - Moretti, Alessandra

AU - Eschenhagen, Thomas

AU - Hansen, Arne

PY - 2014/5/1

Y1 - 2014/5/1

N2 - Contraction and relaxation are fundamental aspects of cardiomyocyte functional biology. They reflect the response of the contractile machinery to the systolic increase and diastolic decrease of the cytoplasmic Ca(2+) concentration. The analysis of contractile function and Ca(2+) transients is therefore important to discriminate between myofilament responsiveness and changes in Ca(2+) homeostasis. This article describes an automated technology to perform sequential analysis of contractile force and Ca(2+) transients in up to 11 strip-format, fibrin-based rat, mouse, and human fura-2-loaded engineered heart tissues (EHTs) under perfusion and electrical stimulation. Measurements in EHTs under increasing concentrations of extracellular Ca(2+) and responses to isoprenaline and carbachol demonstrate that EHTs recapitulate basic principles of heart tissue functional biology. Ca(2+) concentration-response curves in rat, mouse, and human EHTs indicated different maximal twitch forces (0.22, 0.05, and 0.08 mN in rat, mouse, and human, respectively; P < 0.001) and different sensitivity to external Ca(2+) (EC50: 0.15, 0.39, and 1.05 mM Ca(2+) in rat, mouse, and human, respectively; P < 0.001) in the three groups. In contrast, no difference in myofilament Ca(2+) sensitivity was detected between skinned rat and human EHTs, suggesting that the difference in sensitivity to external Ca(2+) concentration is due to changes in Ca(2+) handling proteins. Finally, this study confirms that fura-2 has Ca(2+) buffering effects and is thereby changing the force response to extracellular Ca(2+).

AB - Contraction and relaxation are fundamental aspects of cardiomyocyte functional biology. They reflect the response of the contractile machinery to the systolic increase and diastolic decrease of the cytoplasmic Ca(2+) concentration. The analysis of contractile function and Ca(2+) transients is therefore important to discriminate between myofilament responsiveness and changes in Ca(2+) homeostasis. This article describes an automated technology to perform sequential analysis of contractile force and Ca(2+) transients in up to 11 strip-format, fibrin-based rat, mouse, and human fura-2-loaded engineered heart tissues (EHTs) under perfusion and electrical stimulation. Measurements in EHTs under increasing concentrations of extracellular Ca(2+) and responses to isoprenaline and carbachol demonstrate that EHTs recapitulate basic principles of heart tissue functional biology. Ca(2+) concentration-response curves in rat, mouse, and human EHTs indicated different maximal twitch forces (0.22, 0.05, and 0.08 mN in rat, mouse, and human, respectively; P < 0.001) and different sensitivity to external Ca(2+) (EC50: 0.15, 0.39, and 1.05 mM Ca(2+) in rat, mouse, and human, respectively; P < 0.001) in the three groups. In contrast, no difference in myofilament Ca(2+) sensitivity was detected between skinned rat and human EHTs, suggesting that the difference in sensitivity to external Ca(2+) concentration is due to changes in Ca(2+) handling proteins. Finally, this study confirms that fura-2 has Ca(2+) buffering effects and is thereby changing the force response to extracellular Ca(2+).

KW - Animals

KW - Automation, Laboratory

KW - Calcium Signaling

KW - Cell Differentiation

KW - Humans

KW - Induced Pluripotent Stem Cells

KW - Mice

KW - Mice, Inbred C57BL

KW - Microscopy, Fluorescence

KW - Myocardial Contraction

KW - Myocardium

KW - Myocytes, Cardiac

KW - Rats

KW - Rats, Inbred Lew

KW - Rats, Wistar

KW - Tissue Engineering

U2 - 10.1152/ajpheart.00705.2013

DO - 10.1152/ajpheart.00705.2013

M3 - SCORING: Journal article

C2 - 24585781

VL - 306

SP - H1353-H1363

JO - AM J PHYSIOL-HEART C

JF - AM J PHYSIOL-HEART C

SN - 0363-6135

IS - 9

ER -