[gambit]

Alright, my friend has replied back to me. He worked in a stem cell lab for a month, so he knows a thing or two about the subject. I think he has made some particularly interesting points. For reference, "ESC" is embryonic stem cell, and I assume the little "h" in front stands for human.

Currently, hESC research in the US is limited to the eight cell lines that were derived prior to Bush putting ban on deriving new lines. So the research being done currently doesn't require the killing of embryos or anything like that... ESCs lines are "immortal" in the sense that they can grow and divide indefinitely. However, the US ban on deriving new lines is bad for a number of reasons.

One is that all of the existing hESC lines have been exposed to various animal products like bovine serum and are therefore unsuitable for human therapy. Another is that certain disease models require a different genetic background. For example, a lab outside the US has studied neuron outgrowth in a hESC line derived from a Down's Syndrome embryo. Another reason is that other countries don't have the Bush ban... so while they study genetic diseases and derive hESCs without animal products, the US lags behind.

There are a couple of different ways to get new stem cell lines. The main way is to fertilize an egg and let the embryo develop until it is 32 cells big (the blastula stage). At that point there is a little cluster of pluripotent cells (the inner cell mass), which you can harvest and cultivate in petri dishes as ESCs. This DOES "kill" that embryo, which is where most people get upset.

I put "kill" in quotes, because I think life of an embryo is more complex than a simple on/off state. If people think that human life begins at conception (and in some strictly biological sense, it does), then harvesting stem cells from an embryo may be murder (then again, maybe not... the ESCs being grown in labs are quite alive, biologically). But I feel that the definition of life is more complex than biological functioning. Consider that a brain-dead person on life support is "alive" in the sense that their cells are respirating, and we might feel attached to the body because it resembles a human. But in the sense of human life that has rights and legal protections... I don't see a human there. Without brain activity, it's just biological matter, albeit perhaps uncomfortably similar to a living person. Similarly, a blastula has no neurological activity, so from that standpoint, human ESCs are harvested before an embryo becomes alive in a meaningful way.

I think there's a popular misconception that hESCs are harvested from third-trimester babies or something, but they're not. At the blastula stage, a human embryo is all but indistinguishable from a starfish embryo. However, even IF one strongly feels that killing blastulas is murder, they need to realize that there are thousands of blastulas just going to waste at in-vitro fertility clinics already. IVF clinics don't fertilize just one egg... they take several, and the leftovers are usually frozen for a few years and then discarded. Those embryos are fated to die anyway, so why not do some research good with them? The amount of waste here is really unfortunate.

There's a second way of harvesting hESCs from blastulas, in theory. I don't think it has been done in practice, though this may be because of the moratorium on deriving new lines in the US. Basically instead of pulling all of the inner cells out of the blastula, you pull out just one. Amazingly, the embryo can recover from the loss of a cell or two just fine (fertility clinics do this to determine whether an in vitro fertilized embryo has genetic disorders: pull one cell and analyze its DNA). This technique is much more difficult, partly because individual ESCs don't like to grow when they're isolated and need to exist in colonies. People on this campus and elsewhere are working on developing means to grow ESCs individually though, so that's just a technological hurdle. That technique would allow the embryo to continue developing, although it seems beside the point... odds are it's going to be discarded anyway.

There are a couple of other ways to derive stem cells, although they aren't really tried-and-true. One is called reprogramming, where you take a differentiated adult cell and manipulate it into becoming ESC-like. This has kinda, sorta been done, although the final product is not a true ESC.

There's also another technique called Altered Nuclear Transfer, which I hesitate to even mention because it's so nonsensical to me. Basically the idea is that destroying blastulas is murder because that blastula would have "naturally" grown up to become a baby (which is fallacious, actually... a blastula needs to implant in a womb in order to grow beyond a couple of days old, so a blastula in an IVF clinic will "naturally" expire). But anyway, following that logic, a group of researchers decided to engineer a genetic time-bomb which causes the embryo to "naturally" expire regardless of its setting (nevermind that "natural" now means "following the artificial programming we have given it"). So it's OK to kill an ANT embryo, because it possesses no potential for becoming a baby. Whatever. Bonus points too for circular logic: engineering a genetic time-bomb into a human would be monstrous, but these embryos have no potential for becoming human, so it's OK; they have no potential for becoming human because... they've had a time-bomb engineered into them!

Those are the main ways of acquiring new hESC lines that I know of. Finally, there's some speculation that there are undifferentiated fetal cells floating around in the womb, and these could possibly be cultivated as hESCs once we figure out how. If you've heard of people wanting to freeze their child's umbilical cord blood for potential future use, that's why... there are supposedly ESC-like cells in there. I really haven't kept up on the state of that research though.