BackgroundHuman embryonic stem cells (hESCs) hold tremendous promise for cell replacement therapies for a range of degenerative diseases. In order to provide cost-effective treatments affordable by public health systems, HLA-matched allogeneic tissue banks of the highest quality clinical-grade hESCs will be required. However only a small number of existing hESC lines are suitable for clinical use; they are limited by moral and ethical concerns and none of them apply Good Manufacturing Practice (GMP) standards to the earliest and critical stages of gamete and embryo procurement. We thus aimed to derive new clinical grade hESC lines of highest quality from fresh surplus GMP grade human embryos.MethodsA comprehensive screen was performed for suitable combinations of culture media with supporting feeder cells or feeder-free matrix, at different stages, to support expansion of the inner cell mass and to establish new hESC lines.ResultsWe developed a novel two-step and sequential media system of clinical-grade hESC derivation and successfully generated seven new hESC lines of widely varying HLA type, carefully screened for genetic health, from human embryos donated under the highest ethical and moral standards under an integrated GMP system which extends from hESC banking all the way back to gamete and embryo procurement.ConclusionsThe present study, for the first time, reports the successful derivation of highest-quality clinical-grade hESC lines from fresh poor-quality surplus human embryos generated in a GMP-grade IVF laboratory. The availability of hESC lines of this status represents an important step towards more widespread application of regenerative medicine therapies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-017-0561-y) contains supplementary material, which is available to authorized users.

We have generated a human feeder cell line from early second trimester Placental Stromal Fibroblasts (ihPSF) stably over-expressing the polycomb protein BMI-1. These feeder cells retain the ability to maintain human Embryonic Stem cells (hESc) over long-term culture whereas hTERT or BMI-1/hTERT immortalised feeder cell lines do not. ihPSFs were able to support the derivation of a new hESc line in near xenofree (free of non-human animal components) conditions and support continued culture of newly derived hESc and human induced Pluripotent Stem (hiPS) cell lines in complete xenofree conditions necessary for clinical use.