Scientists at Harvard University and Columbia University have converted skin cells from an 82-year-old woman with amyotrophic lateral sclerosis (ALS) into stem cells that formed motor neurons with the same genetic make up as the patient. The breakthrough opens the possibility of modeling a patient's specific disease outside of the patient, to improve investigation and drug screening, and perhaps even to develop new neurons to replace the damaged ones in the patient. ALS, also known as Lou Gehrig's disease, is a progressive degenerative disease that attacks the motor neurons in the spinal cord, leading to paralysis of limbs and respiration. Induced pluripotent stem cells (iPS cells) were generated from fibroblasts taken from the skin of an 82-year-old woman with a familial form of ALS. The patient-specific iPS cells behaved like embryonic stem cells and differentiated successfully into motor neurons. Recent studies have shown it is possible to reprogram human fibroblasts and return them to a pluripotent state, where they become stem cells that can be coaxed into producing a range of other cells. However, this is the first study to show it is possible to do this with the skin cells of an elderly patient with chronic disease. Despite these breakthrough results further studies are warranted because the cells are only useful if they are exactly the same as the ones causing the disease in the patient, partial replicates would be of little use.

Science. 2008 Jul 31. [Epub ahead of print]