July 14, 2013 | David F. Coppedge

Stem Cell Wars Continue

The race continues between scientists desperately seeking a rationale for harvesting human embryos and those who say, having adult stem cells and iPS cells available, they are unnecessary – and their use is unethical.

Now ear this (ES):  Using mouse embryonic stem cells (ES), researchers at Indiana University have grown inner ear hair cells complete with hair bundles, Science Daily reported.  The cells were grown in a culture that allowed them to hang freely instead of growing on a flat surface as in previous attempts.  It was not clear from the article whether embryonic stem cells, as opposed to iPS or adult stem cells, were required for the success.

Liver vs die-er (iPS):  A different organ was grown with induced pluripotent stem cells (iPS) – a tiny liver grown in a mouse embryo with iPS cells from a human.  Human livers are in high demand for transplants; many die before they become available.  A way to regenerate them would be a huge help.  Nature News described the process:

The researchers make the liver buds from three types of human cells. First, they coax induced pluripotent stem cells into a cell type that expresses liver genes. Then they add endothelial cells (which line blood vessels) from umbilical cord blood, and mesenchymal stem cells, which can make bone, cartilage and fat. These cell types also come together as the liver begins to form in the developing embryo.

The scientists got the cells to “talk to each other and make the organ.”  Live Science added, “The human ‘liver buds’ grew blood vessels and produced proteins such as albumin that are specific to humans.”  The article also said that when transplanted into a dying mouse, the new liver allowed it to live longer.  Treatments for humans with this technique will probably take years, but in the meantime, the researchers are getting good results trying to grow a pancreas, too.  The original paper is in Nature.

Whoops; long-held assumption was wrong (ES)Science Daily published a short article about how a long-held assumption about embryonic stem cell differentiation was wrong.  A certain transcription factor Nanog is not expressed only in one allele, as was previously believed, but in both.  Significance?  “it raises the question for other genes. For some genes, there might be similar issues.”

Safer alternative (iPS):  A better way to reprogram adult cells into iPS cells was reported on PhysOrg.  By developing “designer transcription factors,” researchers at the Wellcome Trust Sanger Institute have found ways to make the reprogramming process more efficient, and safer, too.  Science Daily described another initiative at the University of Toronto that likened their work to reverse-engineering gourmet dinners by finding out that all the chefs used a device called a measuring cup.

Epigenetics of muscle stem cells (AS):  Keeping the pool of stem cells quiescent in muscles is important, but little is known about how they are maintained, and how they change with aging.  In Current Biology, researchers at Stanford found “direct evidence that, with age, epigenetic changes accumulate and may lead to a functional decline in quiescent stem cells” in mouse muscle.

Maintenance crew (ES):  Also in Current Biology, a team of European and Japanese researchers identified a couple of factors, an inhibitor and a cytokine, that appear to be involved in maintaining embryonic stem cells in a totipotent state by shielding them from other differentiating factors.  Their research was done with mice.

The next step down the slippery slope:  The controversy over genetically-modified (GM) foods pales in comparison to what’s coming, the BBC News reported.  It’s synthetic biology – the creation of new living organisms, designer creatures with invented genes, not just chimeras of animals with mixtures of existing genes from different organisms.

For those pioneering this new field, the science offers a whole realm of exhilarating possibilitiesdreaming up and building new organisms that will perform exactly what’s ordered. It is a vision for taking control of nature….

Right from the start of each project, the ethical and environmental implications are considered – the aim being to head off the kind of reactions that GM produced.

Visions of “The Sorcerer’s Apprentice” come to mind.  David Shukman, science editor for the BBC, said that representatives from the UK, US and China are meeting to develop “codes of conduct” for this type of research.  They’re worried about public reaction.

Does anyone see any need for ES cells, now that iPS and AS (adult stem cells) seem to have all the capabilities without the ethical problems?  Let them learn what they need with mouse embryos.  It’s hard to understand why some researchers still want access to human embryos.

As for synthetic biology, the ethics of that will depend on (1) whether human brain cells are being planted in animals, and (2) whether experimentation poses health risks, such as an out-of-control organism that reproduces with no predators to stop it.  Creating a designer bacterium that can detect cystic fibrosis or cancer is a good goal almost no one would object to, but there are boundaries that must be maintained.  Good intentions notwithstanding, scientists are on the verge of letting Frankensteins loose on the world.  They need the oversight of an informed, moral, concerned public.



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