Bakhtiary et al. Iran Biomed J. 2010 Oct;14(4):142-9.

Bone marrow mobilization is used as part of hematopoietic stem cell transplantation in order to collect donor bone marrow stem cells without having to puncture the bone. The process of mobilization is induced by administration of the drug G-CSF, which is approved by the FDA. One interesting question is if instead of giving patients stem cell therapy, if one could simply give G-CSF and have their own stem cells “mobilize” and treated the area of injury. This would be simple and economical as compared to injection of stem cells.

In order to test this, a group from Iran used a rat model of traumatic brain injury and gave either G-CSF or bone marrow derived mesenchymal stem cells.

There were three groups of 10 rats used in the experiments. All rats were subjected to traumatic brain injury by use of a “controlled cortical impact device”. The first group received 2 million bone marrow derived mesenchymal stem cells. The second group received G-CSF to mobilize the bone marrow stem cells. The third group served as a control group. All injections were performed 1 day after injury into the tail veins of rats. The bone marrow derived mesenchymal stem cells were labeled with Brdu before injection into the tail veins of rats. Animals were sacrificed 42 days after TBI and brain sections were stained by Brdu immunohistochemistry.

As compared to controls, both the G-CSF mobilized and the bone marrow mesenchymal stem cell groups had a statistically significant improvement in behavior. When animals were sacrificed at 42 days the observation was made that labeled bone marrow mesenchymal stem cells homed into the area of injury and appeared to contribute to repair.

Although more date is needed when it comes to clinical application, it may be feasible to use G-CSF as part of therapy for traumatic brain injury. One caveat that we find with this is that G-CSF, as its name suggests (granulocyte colony stimulating factor), actually stimulates both increase in granulocyte number and function. While in a controlled laboratory environment brain damage may be relatively “sterile”, in the clinical setting it may be that increased granulocytes may contribute to a higher extent of inflammation and therefore more tissue damage. On the other hand it is possible that mesenchymal stem cells because of their known anti-inflammatory activity may function not only to regenerate the injured brain tissue but also to provide an anti-inflammatory effect.