Stem cells, unlike other cells, can renew themselves for long periods of time though cell division, and under certain laboratory conditions, they can be stimulated into becoming cells with special functions, like insulin producing cells normally found in the pancreas. One of the major hopes is that researching stem cells is they could potentially offer a renewable source of a transplantable tissues, and have a significant impact on the treatment of Parkinson's, Alzheimer's, diabetes, spinal cord injures, and other diseases.
Recent research at Johns Hopkins University shows however that spinal cord injuries, for example, can heal through normal patterns of activity without the need for stem cells. There are both embryonic stem cells, which are derived from embryos that have been fertilized in-vitro and have been donated for research, and adult stem cells.
The major difference between embryonic and adult stem cells is that embryonic stem cells have the ability to become many different cells in the body. While stem cell research offers many possibilities in the treatment of disease, it remains controversial because, among other concerns, in order to create embryonic stem cells, the embryo must be destroyed in order to create embryonic stem cells. At least, that used to be the case.
On June 19th, researchers at the Advanced Cell Technology Company announced that they had found a way to create embryonic stem cells without having to destroy the embryo. This process is an adaptation of a common genetic test used in fertility clinics, known as pre-implantation genetic diagnosis. Even more recently, on February 24th, 2011 it was announced that Advanced Cell Technology, Inc. has been issued a patent on the “single-blastomere” technique which provides for a non-destructive alternative for deriving human embryonic stem cell (hESC) lines. According to Gary Rabin, the ACT's interim chairman and CEO, "Of the more than 150 patents and patent applications related to stem cell therapy and regenerative medicine that ACT owns or licenses, this patent on our single-blastomere technology is one of the most significant."
The company ACT has been clearance from the FDA to proceed with two Phase 1/2 clinical trials in the U.S. for its RPE program, including a Phase 1/2 trial in patients with dry age-related macular degeneration.
Single blast technology uses a one-cell biopsy approach which is similar to the pre-implantation genetic diagnosis (PGD) that is currently used in in vitro fertilization, and does not interfere with the embryo’s developmental potential. Stem cells that have been generated via this approach thus far have been healthy, normal and can be differentiated into all the cell types of the human body.
The current US policy does not allow use of embryos harvested made past August of 2001. On June 20, 2007, the president vetoed a bill that would allow embryos from past that date to be used, and encouraged alternative means of producing stem cells. The president's veto drew strong response from several sources, including the American Fertility Association, who pointed to a study published the same day which showed that, in a survey of 1,000 couples who had stored embryos 60 % said they would donate embryos for stem cell research.