The results of two studies published in the current issue of Cell Transplantation (19:9) using animal models of cerebral ischemia and ischemic stroke in rats may significantly impact the treatment of stroke in humans. One study found that administering bone marrow stromal stem cells (MSC) produced functional and structural recovery in stroke induced rats which coincided with activation of microglia and new blood vessel growth; a second study determined a therapeutic potential when vascular endothelial growth factor (VEGF) administration offered functional and structural protection from ischemic stroke damage;
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Bone marrow stem cells administration promotes functional recovery
The study examining the effects of a systematic administration of either rat (allogenic) or human (xenogenic) bone marrow stem cells administered to laboratory rats one day after their simulated strokes found "significant recovery" of motor behavior on the first day. Early administration was found to be more effective than administration seven days after the simulated strokes.
"The timing of stem cell treatment was critical to the magnitude of the positive effects," said the study's lead author, Dr. Lorraine Iacovitti. "In the host animals we found profound changes and preserved brain structure along with long-lasting motor function improvement."
According to Dr. Iacovitti, there has been little research into just how stem cell transplantation modifies inflammatory and immune effects as well as promotes regenerative effects, such as blood vessel growth. They observed increased activation of microglia as well as modification of the circulating levels of cytokines and growth factors, including elevated VEGF and new blood vessel formation (angiogenesis) following transplantation.
"The mechanism through which MSCs achieve these remarkable effects remains elusive," said Dr. Iacovitti. "It is possible that activated glia cells (nonneuronal cells that perform a number of tasks in the brain) may play some role in the response, perhaps by partitioning off the infarcted region and limiting the spread of ischemic brain damage without inducing scar formation."
The researchers concluded that there was "little doubt" that the administration of stem cells can modify the cellular and molecular landscape of the brain and blood, limiting damage and protecting the stroke-injured brain.
Exploring the current use and future of alternatives to traditional informed consent in acute stroke trials