"A single dose of the cells produce robust behavioral recovery at an early period post-transplantation and the recovery was durable, lasting up to two months, which was the entire length of this study," Dr. Borlongan said. "Furthermore, animals continued to show improvement over time." In the newborn model of ischemic injury, enhanced recovery was found within two weeks.
Even though less than 1 percent of the transplanted cells were present two months later, animals receiving treatment developed new neurons, apparently formed from endogenous stem cells. "The mechanism that we are putting forward is these donor cells are secreting nourishing trophic factors that are helping the host brain cells survive and stimulating stem cells from the host to multiply," Dr. Borlongan said.
To help mimic potential clinical scenarios for stroke victims, transplants were performed seven days after the intitial injury. Currently, ischemic stroke patients may be treated with tPA, the only FDA-approved stroke treatment available, but must receive treatment within three hours from the time the stroke initially occurs. As a result, 95-97 percent of ischemic stroke victims never receive treatment with tPA.
In the adult stroke model, MCG researchers found giving stem cells increased the number of injured cells that survived in the area just outside the area of greatest damage, also referred to as the ischemic core, by 5-20 percent.
"Up to this point, all the treatment approaches, including transplantation and tPA, cannot get rid of that ischemic
Source:Medical College of Georgia