Cryopreservation alters contractile function of human induced pluripotent stem cell-derived cardiomyocytes

Advanced protocols are available for efficient generation of large quantities of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Nevertheless, hiPSC-CMs show large batch to batch variations as well as fetal-like phenotype. Cryopreservation enables long-term storage of batches, leading to increased consistency and reproducibility of data while improving maturation. However, controversial data regarding comparability of fresh and cryopreserved hiPSC-CMs have been reported. Here, we compared fresh and cryopreserved hiPSC-CMs, demonstrating that both cryopreservation media (CryoStor^®CS10 and KnockOut Serum Replacement) had a comparable recovery rate (CS10: 39%, KSR: 46%) and similar proportion of CMs in long-term culture. Cryopreservation altered cell morphology (increased cell area and shorter or longer sarcomere length) and contractile parameters (faster time to peak and half relaxation time and higher or shorter contraction amplitude) of recovered hiPSC-CMs with only slight changes in sarcomeric gene and protein expression. Some differential effects of both cryo-media on CM structure and function were observed. The data indicate an influence of cryopreservation on cell morphology as well as on contraction parameters that should be considered in downstream applications.