An interesting study was published by Gordon et al (Human mesenchymal stem cells abrogate experimental allergic encephalomyelitis after intraperitoneal injection, and with sparse CNS infiltration, Neurosci Lett 2008 Dec 19;448(1):71-3) describing the use of human bone marrow derived mesenchymal stem cells in the treatment of EAE, a mouse model of multiple sclerosis.

Previously people have demonstrated that administration of mouse mesenchymal stem cells into mice with EAE results in remission of disease. In this current paper an interesting, and very relevant variation of the previous study was made….human stem cells were used. This is important since human mesenchymal and mesenchymal-like stem cells are being developed by companies such as Osiris and Medistem as “universal donor” cells. This means that theoretically these cells are not rejected by the immune system. So the authors of this paper wondered whether the human cells would survive in the mouse, and whether they would actually mediate a therapeutic effect.

The investigators induced EAE through administration of the peptide MOG 35-55 together with an adjuvant in order to elicit immune responses against myelin. They injected 1 million mesenchymal stem cells intraperitoneally and found a statistically significant reduction in disease score. Disease score is measured on a scale of 0-5 (0 – Normal; 1 – Tail flaccidity or hind limb weakness; 2 – Partial hind limb paralysis; 3 – Complete hind limb paralysis, spastic paresis, impaired righting reflex; 4 – Complete hind and fore limb paralysis; 5 – Dead).

On day 50 the disease score seemed to have went in remission (about 0.5) in the mice receiving mesenchymal stem cells but was still active (2) in the control mice. Interestingly tracking of the cells showed that few mesenchymal stem cells were found in the brain on day 50.

This paper was really nicely written and provides some good background references for people interested in this area. It is available for free online at this link.