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Posted on Mar 16, 2005, 4 a.m.
By Bill Freeman
Like many neurodegenerative illnesses, Alzheimer's disease is characterized by the uncontrolled death of precious brain cells. But in their unique ability to develop into any cell type, stem cells have long held out the tantalizing hope of replenishing neurons lost to the disease, a process called neurogenesis.
Unfortunately, transplanting these stem cells from outside sources -- such as embryos or bone marrow -- carries its own risks and complications.
But one researcher believes the best solution to Alzheimer's may lie closest to home: within the brain itself.
The activation of dormant stem cells in the patient's own brain could someday allow doctors to re-grow lost cells without resorting to surgery, and in ways that target exactly those areas of the brain -- and specific types of cells -- damaged by disease.
"We're developing maps so that we'll know exactly which stem cells give rise to every cell subtype in the brain," explained Dr. Mark F. Mehler, chairman of the department of neurology at Albert Einstein College of Medicine, and neurologist-in-chief at Montefiore Medical Center, New York City.
"That means, we'll be able to say the equivalent of, 'OK, in sector three of sub-zone 7, we need to activate that cell.' And not only activate it, but activate it in a specific way," he added.
The technique -- still years away from clinical trials -- is called endogenous (meaning sourced from the patient) stem cell activation.
While stem cells sourced from embryos or bone marrow have received the most media attention, residual amounts of these regenerative cells exist throughout the body. According to Mehler, about 0.3 percent of brain cells may be dormant stem cells.
