Alzheimer’s disease is caused by cell death in several areas of the brain. It is a progressive disorder that leads to loss of memory and cognitive abilities. Ultimately, Alzheimer's is fatal. There is currently no cure.
Damage to the brain in Alzheimer’s disease is widespread, making stem celli-based approaches to treatment problematic. Stem cell therapy offers greatest potential for diseases in which specific, well-known types of cell need to be replaced or helped to function correctly. In Alzheimer's disease several different groups of brain cell would need to be replaced, and scientists believe it is highly likely that the signals needed to help transplanted cells integrate into the brain may be absent in the Alzheimer brain.
Stem cells could, however, be genetically modified so as to deliver substances to the Alzheimer brain, to stop cells from dying and stimulate the function of existing cells. A recent clinical triali (Phase I) has shown this approach to be of some benefit to patients with Alzheimer’s disease, by slowing down the progression of the disease.
Relevant links:
alz.org - alzheimer's association research center - good information on the status of current research, future directions and clinical trials
Alzheimer's Society (UK)
Alzheimer Europe