Stroke is a significant cause of long-term disability. Currently, once damage from a
stroke is established little can be done to recover lost function.
Cell transplantation emerged as possible alternative
therapy, on the basis of animal studies showing that cells transplanted into the brain not only survive, but also lead to functional improvement in different
neurodegenerative diseases. Stem cells have been tested in
stroke patients as a possible treatment option. While initially stem cells seemed to work by a 'cell replacement' mechanism, it is emerging that
cell therapy works mostly by providing trophic support to the injured tissue and brain, fostering both neurogenesis and angiogenesis. This review summarizes clinical studies on
stem cell transplantation in
stroke patients to evaluate the safety, feasibility of administration and tolerability of this experimental treatment. At present there is little evidence to assess the applicability of this treatment in
stroke patients and well designed clinical trials are necessary to evaluate safety and toxicity as well as optimal cell type, route and time of delivery.