The road to providing human embryo stem cells for therapeutic use: the UK experience

Harnessing the unparalleled properties of human embryo stem cells (hESCs) for the therapeutic treatment of disease and injury will require a convergence of scientific developments with regulatory standards. In the case of the latter, it is especially critical that standards for clinically assisted reproduction be harmonized with those governing human cell and tissue transplantation, most notably with respect to procurement, donation, testing, processing, preservation, storage and distribution of cells. In the UK, existing infrastructure to address these considerations is undergoing extensive reorganization to keep pace with evolving European Union standards. The present best paradigm for defining standards for the therapeutic use of embryo-derived stem cells is experience with adult haematopoietic stem cells (HSC). However, compared with adult-derived stem cell, the origin of embryo-derived stem cells from limiting quantities of tissue and their absolute dependence on in vitro culture to realise their therapeutic potential, makes optimization of their isolation and cultivation of even greater importance. Most notable is the requirement to create animal cell product-free culture environments to reduce the risk of cross-specific disease transmission. In the present paper, we review present and emerging standards in the isolation and banking of human embryo-derived stem cells for therapeutic use in the UK and international progress in the development of defined culture systems for this purpose.