The contribution of donated human embryos suitable for the production of embryonic stem cells to increase the quality of life: Selection and preparation of embryos in the Czech Republic

Human embryonic stem cells (hESCs) have the unique ability to differentiate into any cell type in the human body and to proliferate indefinitely. Cell therapies involving hESC have shown very promising results for the treatment of certain diseases and confirmed the safety of hESC-derived cells for humans. They are used in cell therapy, mainly in targeted therapy of diseases that are currently incurable.The aim of this study was the derivation of clinical-grade hESCs usable in drug development, non-native medicine and cell therapy.Embryos were thawed, cultivated to the blastocyst stage if necessary, and assisted hatching was subsequently performed. Embryoblasts were mechanically isolated using narrow needles. Each line was kept as a separate batch. The derived hESCs were cultured under hypoxic culture conditions (5% O2, 5% CO2, 37°C) in a NutriStem® hPSC XF Medium with a daily medium change.From January 2018 to July 2020, 138 selected clients were asked for consent to donate embryos, of whom 52 did not respond, 19 terminated the storage of their embryos and 29 extended the storage. Only 38 clients (27.5%) agreed to donate embryos for the derivation of hESCs. At the same time, personal communication with clients took place and another 17 embryo donors were recruited. A total of 160 embryos from 55 donors aged 26-42 years were collected. The embryos were frozen at the blastocyst (33.1%) or morula (46.3%) stage. After the preparation of 64 embryos, embryoblasts were isolated and cultured. Finally, 7 hESC lines were obtained, 4 research-grade and 3 clinical-grade, the first in the Czech Republic.We established a current good manufacturing practice (cGMP)-defined xeno-free and feeder-free system for the derivation, culture and banking of clinical-grade hESC lines that are suitable for preclinical and clinical trials. The quality control testing with criteria concerning sterility, safety and characterization according to cGMP ensured the clinical-grade quality of hESC lines.