Friday, September 6, 2013

Stem cell stories that caught our eye: ethics of little brains, heart repair, and tracking transplanted cells

Here are some stem cell stories that caught our eye this past week. Some are groundbreaking science, others are of personal interest to us, and still others are just fun. 

The ethics of brain clumps in a dish. Late last week and through the weekend headlines around the world proclaimed that scientists had created little human brains in a dish. Actually they created small 3-diemnsional clumps of cells containing several types of brain cells but in groups that were more like they had been passed through an eggbeater than the organized structures of a fetal human brain. Those pea-sized chunks of brain tissue were not remotely close to the size of a human brain, but not that much smaller than a mouse brain. This led a writer at Discover, a neuroscientist who writes under the byline “Neuroskeptic” to raise the question of whether or not those clumps of cells should raise ethical issues. That piece is here.

He reasoned that these brain structures are unlike other artificial organ parts created in the lab recently because the brain confers our sense of being, and ends up as an organ that defines who we are. For that reason he says this work should be treated differently. He did not draw the conclusion that this work was unethical, particularly at this early stage, but says that as the work progresses, the ethics needs to be considered.

An earlier piece in the news section of the journal Nature did a good job of explaining what the work was and what it was not. It quotes two CIRM grantees, Arnold Kriegstein at the University of California, San Francisco and Clive Svendsen at Cedars-Sinai.

Gene therapy added to stem cells for heart repair. Many teams have reported using stem cells found in blood and bone marrow to try to get the heart to repair itself after heart attack. Those clinical trails have generally reported positive results, but very modest positive results. Now a team at the University of Ottawa is trying to increase the effectiveness by modifying the stem cells after they are harvested from the patient’s blood. They are adding an extra copy of a gene that stimulates blood vessel growth, an important part of repairing heart tissue damaged by a heart attack. A story about the team treating their first patient appeared in Health Canal.

Eight of CIRM’s 23 Disease Team awards, our projects closest to clinical trials, also involve combinations of gene therapy with stem cell therapy. One of those launched a clinical trial earlier this summer. The press release announcing their first patient is here.

Markers track cells after transplant. A number of current clinical trials use stem cells’ presumed ability to home to inflammation to deliver an anti-inflammatory payload. This is often proteins the cells naturally secrete. Other times the cells are rigged with extra genes to produce anti-inflammatory agents. And in a couple cases, one funded by CIRM, they are loaded with anti-cancer agents with the assumption that stem cells view cancer as inflammation. But it has been hard to prove cells really do home to inflammation. Now two different journal articles this week describe clever ways to track the stem cells after transplant without harming them or their payload.

One team loaded the cells with tiny iron fragments that can be detected by magnetic resonance imaging. CIRM-grantee Karen Aboody at City of Hope leads that work looking at brain cancer, and was blogged about this morning by my colleague here. The press release from the journal Stem Cells Translational Medicine, which CIRM helped to launch, was picked up by the Benzinger web news portal.

The second team, at Rice University in Houston, used a different imaging technology, computed tomography, or CT scans. The technology can easily track the compound bismuth in the body. So, the team trapped bismuth in tiny nanotube cages and inserted them into stem cells. The Science Daily web site wrote about the work here.

Scientists urged to get out of the lab and talk. Not to each other at scientific meetings, but rather to talk to the public face-to-face and online. Paul Knoepfler makes this pitch in an opinion piece published this morning in Nature Medicine. He reasoned that scientists have a responsibility to foster understanding of their work amongst the public that funds the work through taxes. That premise has long been a soap box of mine. So, I could not agree more with Paul, a CIRM grantee at the University of California, Davis, and someone I am happy to call a colleague in the blogosphere.

Don Gibbons

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