title: A Long-Gap Peripheral Nerve Injury Therapy Using Human Skeletal Muscle-Derived Stem Cells (Sk-SCs): An Achievement of Significant Morphological, Numerical and Functional Recovery.
abstract: Losses in vital functions of the somatic motor and sensory nervous system are induced by severe long-gap peripheral nerve transection injury. In such cases, autologous nerve grafts are the gold standard treatment, despite the unavoidable sacrifice of other healthy functions, whereas the prognosis is not always favorable. Here, we use human skeletal muscle-derived stem cells (Sk-SCs) to reconstitute the function after long nerve-gap injury. Muscles samples were obtained from the amputated legs from 9 patients following unforeseen accidents. The Sk-SCs were isolated using conditioned collagenase solution, and sorted as CD34+/45- (Sk-34) and CD34-/45-/29+ (Sk-DN/29+) cells. Cells were separately cultured/expanded under optimal conditions for 2 weeks, then injected into the athymic nude mice sciatic nerve long-gap model (7-mm) bridging an acellular conduit. After 8-12 weeks, active cell engraftment was observed only in the Sk-34 cell transplanted group, showing preferential differentiation into Schwann cells and perineurial/endoneurial cells, as well as formation of the myelin sheath and perineurium/endoneurium surrounding regenerated axons, resulted in 87% of numerical recovery. Differentiation into vascular cell lineage (pericyte and endothelial cells) were also observed. A significant tetanic tension recovery (over 90%) of downstream muscles following electrical stimulation of the sciatic nerve (at upper portion of the gap) was also achieved. In contrast, Sk-DN/29+ cells were completely eliminated during the first 4 weeks, but relatively higher numerical (83% vs. 41% in axon) and functional (80% vs. 60% in tetanus) recovery than control were observed. Noteworthy, significant increase in the formation of vascular networks in the conduit during the early stage (first 2 weeks) of recovery was observed in both groups with the expression of key factors (mRNA and protein levels), suggesting the paracrine effects to angiogenesis. These results suggested that the human Sk-SCs may be a practical source for autologous stem cell therapy following severe peripheral nerve injury.
authors.affiliation: Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.|Department of Human Structure and Function, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Tetsuro
authors.identifier: http://orcid.org/0000-0002-9071-049X
authors.initials: T
authors.lastname: Tamaki
authors.affiliation: Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.|Department of Orthopedics, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Hirata
authors.affiliation: Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.|Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Nakajima
authors.affiliation: Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.|Department of Otolaryngology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Saito
authors.affiliation: Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.|Department of Orthopedics, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hashimoto
authors.affiliation: Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.|Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Soeda
authors.affiliation: Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.|Department of Orthopedics, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Uchiyama
authors.affiliation: Department of Orthopedics, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D051379:Mice; D018482:Muscle, Skeletal / Q000254:growth & development / Q000503:physiopathology; D009186:Myelin Sheath / Q000378:metabolism; D009416:Nerve Regeneration; D059348:Peripheral Nerve Injuries / Q000503:physiopathology / Q000628:therapy*; D020127:Recovery of Function; D012583:Schwann Cells / Q000378:metabolism; D012584:Sciatic Nerve / Q000254:growth & development / Q000293:injuries* / Q000503:physiopathology; D033581:Stem Cell Transplantation; D013234:Stem Cells