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.
Phosphate-buffered saline (PBS group [Group 1]), 105 fresh CD133+ cells (fresh group [Group 2]), 105 ex vivo expanded CD133+ cells (expansion group [Group 3]), or 104 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.
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.
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.
Source: Journal of Neurosurgery.