A woman presented herself in Dr. Allan Wu's office with a symptom the cosmetic surgeon had never before encountered: she heard a distinct clicking sound, "like a tiny castanet snapping shut," every time she opened her right eye. The eye was painful and swollen. When Wu operated, he found bone shards growing inside her eyelid.

Why did this happen? Because the patient had previously undergone a facelift that used her own adult stem cells. Stem cells — as is their wont — will grow into a variety of tissues. Under certain conditions, that includes bone. As Scientific American reports:

First, cosmetic surgeons had removed some the woman's abdominal fat with liposuction and isolated the adult stem cells within — a family of cells that can make many copies of themselves in an immature state and can develop into several different kinds of mature tissue. In this case the doctors extracted mesenchymal stem cells — which can turn into bone, cartilage or fat, among other tissues — and injected those cells back into her face, especially around her eyes. The procedure cost her more than $20,000, Wu recollects. Such face-lifts supposedly rejuvenate the skin because stem cells turn into brand-new tissue and release chemicals that help heal aging cells and stimulate nearby cells to proliferate.

During the face-lift her clinicians had also injected some dermal filler, which plastic surgeons have safely used for more than 20 years to reduce the appearance of wrinkles. The principal component of such fillers is calcium hydroxylapatite, a mineral with which cell biologists encourage mesenchymal stem cells to turn into bone — a fact that escaped the woman's clinicians. Wu thinks this unanticipated interaction explains her predicament.

Quite the unanticipated interaction, there.

The F.D.A. has not approved stem-cell facelifts or the use of stem cells in cosmetic procedures. And creams and pills, mostly untested and of unknown risk potential, that purport to contain stem cells have been proliferating in the beauty products aisle — beauty products are considered "personal-care products" in the U.S., a category which is subject to light-to-no regulation. (There is a wealthy lobby dedicated to keeping it that way, which last year defeated a bill that would have given the F.D.A. some oversight of personal-care products.) Reports Scientific American, "The increasing number of untested and unauthorized stem cell treatments threaten both people who buy them and researchers hoping to conduct clinical trials for promising stem cell medicine." So, great! Just great. I'm going to have nightmares about eyelids growing bone shards tonight.

In the Flesh: The Embedded Dangers of Untested Stem Cell Cosmetics [Scientific American]

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