Nightline - Stem Cells

Jcantu;

I'm curious what's your background? You seem pretty knowledgeable about this stuff.

I'm not a doctor or a scientist myself by my father is doing research on cell biology and I have a few friends who are also biologists so I try to keep up with stuff like this.

 

I'm a medical doctor, with an undergrad degrees in micro and biochem. I am not as up to date as your father is on the subject (or probably your friends either) but I know how it relates to the type of work that I do.


MartianMan,
I again was playing devil's advocate, ovbiously if embryonic stem cells offer the most reward, I want focused research. However, the harvesting method is cruel and unusual to a large percentage of the population and forced alternative routes sometimes yield the best results (i.e. the blessing in disguise way of thinking).

 

Mixed blessings make the world a lot more interesting.

Double triumph in stem cell quest
WITH great fanfare a South Korean team announced last week that it had used therapeutic cloning to create human embryonic stem cells that were genetically matched to specific people. But their technique could already be obsolete.

Another team headed by Yuri Verlinsky of the Reproductive Genetics Institute, based in Chicago, claims to have produced patient-matched embryonic stem cells without resorting to therapeutic cloning. "It would be a much better approach," he says.

Verlinsky says he has already created 10 embryonic stem cell (ESC) lines using his new "stembrid" technique. Unlike therapeutic cloning, it uses existing ESCs instead of human eggs, and so would be much cheaper and easier. What's more, because no embryos are destroyed, it would bypass many ethical issues.

"If it is as he said, it would be spectacular," says Jacques Cohen of Tyho-Galileo Research Laboratories, who has been investigating alternative sources of ESCs. But he and other experts say Verlinsky must do a lot more work to prove his claim.

While ESCs show great promise for treating many diseases, such as heart disease, diabetes and Parkinson's, non-matching ESCs would be rejected by patients' immune systems unless they take immunosuppressant drugs. This is why many stem cell researchers are trying to create ESCs that are identical to people's own cells.

...

But if Verlinsky's claims stand up, there might be a much easier way to create matching ESCs. His method starts with an existing human ESC line. The nuclei containing the DNA of the ESCs are removed by spinning them in a centrifuge. Verlinsky would not reveal the details of his technique, but other teams glue cells to a surface and spin them until the denser nucleus is forced out.

Then the team take cells from adults and fuse them with the enucleated ESCs. The idea is that the cytoplasm of an enucleated ESC will reprogram the donor nuclei, turning the fused cell into an ESC too. The result, Verlinsky told a conference on pre-implantation genetics in London last week, is new lines of ESCs that are genetically identical to the adult donor. He calls the new cells stembrids.

...

The biggest question, though, is whether the stembrids really are true ESCs. Verlinsky says the cells express a number of ESC markers. His team has also shown the cells can differentiate into a number of cell types, including heart muscle cells, neurons and blood stem cells, although the results have not yet been published.

“Stembrids can differentiate into several cell types, including heart muscle cells, neurons and blood stem cells”

Trounson, whose team has been experimenting with a similar approach, says far more detailed studies will be needed. Besides looking at further cell surface markers, Verlinsky's team must show that, like true ESCs, the stembrids are capable of forming cancers called teratomas, which contain a mixture of different cell types, when injected into immune-compromised mice, Trounson says. "Until they have done these studies, we must remain very sceptical."

 

Invisible fan;

I heard that same research mentioned on Science Friday on NPR but they said that they haven't published yet but interesting stuff.

A couple of things though rise to my attention. One, is that this is still therapeutic cloning even if they don't call it that and embryos were destroyed to get the existing ESC lines. The other issue I'm wondering about is how viable are the existing ESC lines? Will there be a point where they are no longer usable? Also I've heard about contamination of many of the existing ESC lines with mouse cells so will a process like this be able to weed out contamination?

 

I think that the majority of conservatives have a problem with the destruction of the fetus for the stem cells and not the research in general (although I'm not sure if that accounts for all). In other words, I think only the most zealot of the bunch wouldn't be pleased with therapeutic cloning as the harvest procedure.

The existence of the lines is probably not in jeopardy. The HeLa line (although not stem cells) has been around since the 50's.

I'm not sure about contamination.

 

My understanding of the opposition towards therapeutic cloning is two fold. One is the destruction of embryos and ovum to collect the cells needed to put the new nuclear material into and then the second is that a new being is being created. If we believe personhood begins at conception then cloning is conception by other means but the end result is a new person being created. In this case that person will be used strictly for research or therapy which many would find unethical and even the deliberate murder of a new human life.

Thanks for the info about the ESC.

 

Hardcore conservatives didn't like the already destroyed embryos aspect of Bush's compromise, and they didn't how it didn't halt private research. The promise of stembrids is that it'll allow ESC research in states other than California....

The problem with sanctioned ESC lines is that they weren't designed for long term study. There's a isn't known point of a stem cell's viability. There's no definite answer on how they specifically crash or change into different cells. Around 2003, there were about a dozen were reportedly usable for research. Four lines were being heavily used among researchers.

I don't know if the stembrid process will weed out mouse contamination. It doesn't sound like it will because the stembrids rely on stem cell cytoplasm to assume its properties. Legally, the FDA will still term it a xenotransplant if any research ever heads to clinical studies. Bush's science advisors knew that point would be decades away.