CARLSBAD Signs of Parkinson's disease have been relieved in a small animal study conducted by International Stem Cell Corp., which is developing its own kind of stem cell therapy for various diseases.
The study used rats and monkeys to test the therapy's ability to replace the kind of brain cells destroyed in Parkinson's and relieve the disease's movement disorders. The animals were given a neurotoxin to induce Parkinson's symptoms. Rats showed improved movement and the monkeys produced higher levels of dopamine, a neurotransmitter essential for movement.
Study results will be presented Wednesday at the annual meeting of the American Academy of Neurology at the San Diego Convention Center.
The results indicate the approach is worth pursuing, said study co-author Evan Snyder, who heads the stem cell and regenerative biology program at Sanford-Burnham Medical Research Institute.
"Being able to show that the cells are there, and that they're safe, certainly is the first step," before human testing, Snyder said. "One needs to do monkeys before you can have a treatment."
Carlsbad-based International Stem Cell is researching therapy with parthenogenetic stem cells, which are made from unfertilized human egg cells. The company says parthenogenetic stem cells present a less questionable approach to stem cell therapy than using human embryonic stem cells, which are taken from human embryos. The company says parthenogenetic-derived cells are also less likely be rejected by the immune system.
Researchers transplanted the newly produced human brain cells into rats and African green monkeys. Months after treatment, the treated rats moved more normally, and the treated monkeys produced more dopamine. Controls were used in both groups. A total of eight green monkeys were used in the study. Four monkeys were treated, two given a sham treatment and two not given any treatment.
A related study published Friday, in which Snyder was also involved, provided evidence of a more efficient way of turning human parthenogenetic stem cells into dopamine-producing neurons.
Researchers led by Jeanne Loring at The Scripps Research Institute in La Jolla are pursuing a similar treatment. Loring and colleagues are using induced pluripotent stem cells, artificially produced stem cells that also act like embryonic stem cells. These IPS cells can be produced from skin cells, making it possible to grow the cells directly from patients to be treated.