title: Articular cartilage repair with magnetic mesenchymal stem cells.
abstract: BACKGROUND
  Cell therapies are hampered by the difficulty of delivering cells to and retaining them in target tissues long enough to repair or regenerate local tissues.
  
  
  OBJECTIVE
  Magnetic-assisted delivery of magnetically labeled mesenchymal stem cells (m-MSCs) would be rapid, allowing for chondrogenic differentiation and functional joint repair without replacement.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Sixteen mini-pigs aged 6 to 7 months were used. A full-thickness cartilage defect was created in the center of the patella with a cylindrical punch (diameter, 6 mm). At 4 weeks after creation of the cartilage defects, the animals were divided into 3 treatment groups: In the M group, m-MSCs (5 × 10(6) cells) were injected and accumulated to the cartilage defect using an external magnetic force (1.5 T) for 10 minutes; in the G group, the patella was faced upward, filled with MSCs (5 × 10(6) cells), and held for 10 minutes; and in the C group, only phosphate-buffered saline was injected. The regenerated cartilage was evaluated in 5 knees in each of the 3 groups by arthroscopic surgery at 6 and 12 weeks and histological and ultrasound evaluation at 12 and 24 weeks.
  
  
  RESULTS
  The mean arthroscopic scores at 6 weeks were 10.4 ± 1.10 in the M group, 8.8 ± 0.84 in the G group, and 7.4 ± 0.89 in the C group. There was a statistically significant difference between the M group and the other 2 groups. The mean arthroscopic scores at 12 weeks were 12.8 ± 1.30 (M group), 10.5 ± 1.30 (G group), and 9.5 ± 0.58 (C group), with a statistically significant difference between the M and C groups. The mean histological scores using the Wakitani scoring system at 12 weeks were 2.8 ± 0.96 (M group), 5.4 ± 0.55 (G group), and 6.0 ± 2.20 (C group), and the mean histological scores at 24 weeks were 2.4 ± 1.50 (M group), 3.5 ± 0.56 (G group), and 5.3 ± 1.50 (C group). The mean histological scores at 12 weeks were significantly better in the M group than in the other groups, and the M group maintained a significantly better histological score than did the C group at 24 weeks.
  
  
  CONCLUSIONS
  The m-MSCs had no adverse effect on chondrogenic differentiation, and m-MSCs delivered by magnetic field application repaired cartilage defects.
  
  
  CONCLUSIONS
  The clinical application of this novel stem cell delivery system is a potential therapeutic option for treating cartilage defects and may be more applicable throughout the body than traditional methods.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Biomedical Science, Hiroshima University, Hiroshima, Japan.
authors.forename: Goki
authors.initials: G
authors.lastname: Kamei
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Shingo
authors.initials: S
authors.lastname: Ohkawa
authors.forename: Wirat
authors.initials: W
authors.lastname: Kongcharoensombat
authors.forename: Nobuo
authors.initials: N
authors.lastname: Adachi
authors.forename: Kobun
authors.initials: K
authors.lastname: Takazawa
authors.forename: Hayatoshi
authors.initials: H
authors.lastname: Shibuya
authors.forename: Masataka
authors.initials: M
authors.lastname: Deie
authors.forename: Koji
authors.initials: K
authors.lastname: Hattori
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Goldberg
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D000818:Animals; D001182:Arthroscopy; D002358:Cartilage, Articular / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery*; D002454:Cell Differentiation; D049109:Cell Proliferation; D019902:Chondrocytes / Q000166:cytology*; D003911:Dextrans; D060526:Magnetic Fields; D058185:Magnetite Nanoparticles; D045164:Mesenchymal Stem Cell Transplantation; D010329:Patella; D012038:Regeneration; D018709:Statistics, Nonparametric; D013552:Swine
chemical_list: D003911:Dextrans; D058185:Magnetite Nanoparticles; C065507:ferumoxides
keywords: articular cartilage repair; external magnetic force; magnetically labeled mesenchymal stem cells