The therapeutic potential of ex vivo expanded CD133+ cells derived from human peripheral blood for peripheral nerve injuries.

OBJECT: CD133(+) cells have the potential to enhance histological and functional recovery from peripheral nerve injury. However, the number of CD133(+) cells safely obtained from human peripheral blood is extremely limited. To address this issue, the authors expanded CD133(+) cells derived from human peripheral blood using the serum-free expansion culture method and transplanted these ex vivo expanded cells into a model of sciatic nerve defect in rats. The purpose of this study was to determine the potential of ex vivo expanded CD133(+) cells to induce or enhance the repair of injured peripheral nerves.

METHODS

Phosphate-buffered saline (PBS group [Group 1]), 10(5) fresh CD133(+) cells (fresh group [Group 2]), 10(5) ex vivo expanded CD133(+) cells (expansion group [Group 3]), or 10(4) fresh CD133(+) cells (low-dose group [Group 4]) embedded in atelocollagen gel were transplanted into a silicone tube that was then used to bridge a 15-mm defect in the sciatic nerve of athymic rats (10 animals per group). At 8 weeks postsurgery, histological and functional evaluations of the regenerated tissues were performed.

RESULTS

After 1 week of expansion culture, the number of cells increased 9.6 ± 3.3-fold. Based on the fluorescence-activated cell sorting analysis, it was demonstrated that the initial freshly isolated CD133(+) cell population contained 93.22% ± 0.30% CD133(+) cells and further confirmed that the expanded cells had a purity of 59.02% ± 1.58% CD133(+) cells. However, the histologically and functionally regenerated nerves bridging the defects were recognized in all rats in Groups 2 and 3 and in 6 of 10 rats in Group 4. The nerves did not regenerate to bridge the defect in any of the rats in Group 1.

CONCLUSIONS

The authors' results show that ex vivo expanded CD133(+) cells derived from human peripheral blood have a therapeutic potential similar to fresh CD133(+) cells for peripheral nerve injuries. The ex vivo procedure that can be used to expand CD133(+) cells without reducing their function represents a novel method for developing cell therapy for nerve defects in a clinical setting.