Sure, embryonic stem cell research continues, in other countries. Does it make sense to allow Federal funding of work using cell lines that are suboptimal and cannot be used for therapeutic uses, or but not allow research to use the more currently available lines that have greatly improved in the past few years? I'd rather see research on the more recently derived lines, and toward developing even more improved lines that have greater therapeutic potential.
Since some don't want to believe my words, I'll let the published works speak for themselves.
Biology of Reproduction 68, 2150–2156 (2003)
Human Feeder Layers for Human Embryonic Stem Cells1
M. Amit3,4, V. Margulets4, H. Segev3, K. Shariki3, I. Laevsky5, R. Coleman4 and J. Itskovitz-Eldor2,3
Department of Obstetrics and Gynecology,3 Rambam Medical Center, The Bruce Rappaport Faculty of Medicine,4 Technion-Israel Institute of Technology, Genetic Institute,5 Cytogenetics, Rambam Medical Center, 31096 Haifa, Israel
http://www.biolreprod.org/cgi/content/abstract/68/6/2150?ijkey=PWdHbmNVRV7xc
The first reports on the derivation of human ES cells described the necessity for a mouse embryonic fibroblast (MEF) feeder layer to grow continuously in an undifferentiated stage in culture [3, 4]. Contrary to human ES, mouse ES cells can be grown directly on gelatin-coated plates with the addition of leukemia inhibitory factor [5]. Handling the simultaneous growth of both ES cells and MEF requires meticulous care and may prove to be rather expensive. In addition, the dual growth of these cells exposes the human ES cells to mouse retroviruses, which may prevent their future use in cell-based therapy.
Another suggested solution is a culture system based on a human feeder layer. Recently, Richards et al. [8] reported the possibility of growing human ES cells on human embryonic fibroblasts or adult fallopian tube epithelial feeder layers. Cultured with these human feeder layers in medium supplemented with human serum, human ES cells were found to maintain ES cell features, including pluripotency, morphology, and expression of cell-surface markers, for at least 20 passages. This condition was also found to support the derivation of a line similar to human ES cell.
In the present study, we offer an alternative and completely animal-free culture condition for human ES cells based on foreskin feeders and a serum-free medium.
Reproduction (2004) 128 259-267
Derivation, growth and applications of human embryonic stem cells
Miodrag Stojkovic, Majlinda Lako, Tom Strachan and Alison Murdoch1
Institute of Human Genetics, University of Newcastle, Newcastle upon Tyne, NE1 3BZ, UK and 1 Newcastle Fertility Centre at Life, NHS, Newcastle upon Tyne, NE1 4EP, UK
http://www.reproduction-online.org/cgi/content/full/128/3/259
From the abstract:
Human embryonic stem (hES) cells are pluripotent cells derived from the inner cell mass cells of blastocysts with the potential to maintain an undifferentiated state indefinitely. Fully characterised hES cell lines express typical stem cell markers, possesses high levels of telomerase activity, show normal karyotype and have the potential to differentiate into numerous cell types under in vitro and in vivo conditions. Therefore, hES cells are potentially valuable for the development of cell transplantation therapies for the treatment of various human diseases. However, there are a number of factors which may limit the medical application of hES cells: (a) continuous culture of hES cells in an undifferentiated state requires the presence of feeder layers and animal-based ingredients which incurs a risk of cross-transfer of pathogens; (b) hES cells demonstrate high genomic instability and non-predictable differentiation after long-term growth; and (c) differentiated hES cells express molecules which could cause immune rejection. In this review we summarise recent progress in the derivation and growth of undifferentiated hES cells and their differentiated progeny, and the problems associated with these techniques. We also examine the potential use of the therapeutic cloning technique to derive isogenic hES cells.
Sufficient numbers of donated embryos and an in vitro culture system that allows development of early embryos into blastocysts with well-formed ICMs are crucial factors in the successful derivation of hES cells. To date, the majority of described hES cell lines were derived from day 5 to day 8 blastocysts produced for clinical purposes after in vitro fertilisation (IVF) or intracytoplasmic sperm injection. Meanwhile, one hES cell line has been derived from blastocysts developed from embryos reconstructed using a somatic cell nuclear transfer (SCNT) technique (Hwang et al. 2004).
