Forget about regenerating damaged heart tissue or curing autoimmune diseases like Type 1 diabetes. Thanks to the pioneering work of surgeons in Japan and Europe (and a few other companies around the world), human stem cells are being put to an entirely different use: breast augmentations.

According to the Wall Street Journal, the whole "implanting real fat into your boobs" idea never really caught on because the grafted fat tends to die once it's injected, resulting in calcifications or hard lumps. Not the ideal post-surgery scenario. But now, surgeons are experimenting with a new method: They remove some fat from, say, the patient's thigh. They process half of the fat to extract its stem cells (fat is a natural source of adult stem cells and doesn't raise the ethical issues that surround embryonic stem cells). Then they add the extracted stem cells to the other batch of fat, and inject the mixture into the patient's breasts. Supposedly, the stem cells encourage blood flow to the transplanted fat, making the grafted fat less likely to die and thus resulting in an implant that better resembles real breast tissue. What's more, since the stem cells come from the patient's own body, there's no risk of rejection.

The only problem? No one's really sure if the stem cell supplement actually helps the fat grafts survive or, for that matter, what the long-term health risks of such implants might be. According to the Journal, "some doctors worry [that] the fat, when reinjected in the breast, could calcify and interfere with mammographic cancer screening. Another concern is that fat injections could increase the risk of breast cancer, because certain anticancer drugs work in postmenopausal women by inhibiting the production of estrogen, a hormone in fat tissue."

So there's that. Also, there's the question, in the United States at least, of who would regulate the technique because the Food and Drug Administration is responsible for regulating products and devices but not procedures. Since this method uses the patient's own fat and stem cells, it falls in a gray area -- according to the Journal, the FDA does believe that "fat augmented with stem cells creates a 'biological product' that would require regulatory approval," but some doctors argue that since they're just using the patient's own fat, that shouldn't be the case. Nonetheless, commercialization trials are going forward in Japan and Europe, and a company called Cytori, which has invested about $100 million in creating a device that automatically processes cells for implants, is pushing for trials to begin in the United States as well.

I can understand the desire for, say, breast cancer survivors to able to regain realistic-looking breasts, but I do find it hard to stomach the idea that the profit motives are such that companies are willing to invest so much money into something so purely cosmetic. I hope that similar efforts are being made to use stem cells from human fat -- which the Journal describes as having "therapeutic potential" -- for less superficial purposes.