First clinical use of embryonic stem cells approved

January 24, 10:20 AMScience News ExaminerMeg Marquardt

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On Friday, the FDA approved the first clinical trial of a medical therapy based on embryonic stem cells.  The company who will carry out the experiments, the San Francisco-based Geron, called it historic.  “For us, it marks the dawn of a new era in medical therapeutics. This approach is one that reaches beyond pills and scalpels to achieve a new level of healing,” Geron Chief Executive Dr. Thomas Okarma said. [Reuters]

The company will use the stem cells in a therapy to attenuate the effects of spinal paralysis.  By using embryos donated through in vitro-fertilization treatments, they will coax the stem cells into a cell line known as oligodendrocyte progenitor cells (cells that help protect neurons and which are often the heavily damaged in diseases that cause paralysis), and then inject them into the patients.  While this is a very exploratory study (as nothing of the kind has been done before), the company hopes to see some recovery of movement in the patients, for they have seen some return of mobility in mouse models of the experiment.

While the spokeswoman for the company stated that the timing of the FDA approval had nothing to do with the inauguration (that it simply took some time to get through the 21,000 page document they had sent to the FDA), it is difficult not to wonder at the fact that an embryonic stem cell study was suddenly given the green light only days after Bush, who was very vocal in his dislike of the use of embryonic stem cells, left the White House and Obama, who has promised a more pragmatic and scientific approach to the subject, took office.

Controversy over stem cell research is long standing.  Much of the debate arises in the use of embryonic stem cells as opposed to adult stem cells.  While adults do retain stem cells that help the body recover from injury as well as aiding in normal cell turnover (like replacement of skin cells), they also have stem cell-like 'progenitor cells,' which are a more rigid type of cell that only morph into specific target cells.  Embryonic stem cells, however, are able to change into any cell in the body and can be used to grow a limitless supply of those cells.  So while adult progenitor cells can be used for certain studies, they cannot be used for all.  The argument put forth by scientists is, in short, the use of embryonic stem cells would prove a more efficient and more reliable way to search for treatments to debilitating diseases.

The objection to the use of embryonic stem cells has long been for moral and religious reasons, though there are some who argue from a scientific stance.   Josephine Quintavalle, director of Comment on Reproductive Ethics (Core), which opposes embryonic stem cell therapies, dismissed the research as "highly speculative". "The work is at a highly experimental stage and there's still a question mark over the capacity of these cells to form tumours," she said.  [BBC]  And that is true.  It has been shown in experiments that if stem cells are injected directly into a patient, they will grow out of control into cancers known as teratomas.  However, as stated above, studies such as these first coax stems cells into a specific progenitor line (such as the oligodendrocyte progenitor cells), usually by growing them in a solution that contains nutrients and other factors that the body would use to signal the need for a specific cell.  Once the specific cell line is established, then they will be injected into a patient.  When they are recognized by the body, the cells then should differentiate (or change) in a more controlled manner into the proper cell.

The FDA approval is a pivotal step in therapeutic medicine.  If successful, use of embryonic stem cells may pave the way for treatments of diseases that are known to be caused by the degradation of specific cell types.  Okarma said: "What stem cells promise for a heart attack or spinal cord injury or diabetes is that you go to the hospital, you receive these cells and you go home with a repaired organ, that has been repaired by new heart cells or new nerve cells or new islet cells that have been made from embryonic stem cells." [BBC]

Professor Pete Coffey, director of the London Project to cure blindness, summarized the FDA decision quite eloquently: "It's great news for the field." [BBC]