title: Viability and proliferation of pluripotential cells delivered to tendon repair sites using bioactive sutures--an in vitro study.
abstract: OBJECTIVE
  We evaluated the fate of pluripotential stem cells adherent to a suture carrier after being passed through tendon tissue in vitro.
  
  
  METHODS
  FiberWire suture segments were coated with poly-L-lysine (PLL) and a 2 × 10(6) C3H10T1/2 (a mouse embryo pluripotential cell line) cell suspension. The sutures were incubated for 7 days, passed through two 1-cm segments of acellularized rabbit Achilles tendons and tied (horizontal mattress). The repairs were frozen and sectioned (6 μm). The sections were stained with 4',6-diamidino-2-phenylindole and a live/dead viability/cytotoxicity (calcein/ethidium homodimer) kit and examined with fluorescent microscopy to evaluate cell presence and viability. Alamar Blue was used in parallel to assess metabolic activity.
  
  
  RESULTS
  PLL-coated sutures showed a 3-fold increase in fluorescence when compared with the phosphate-buffered saline-coated controls. At day 3, fluorescence was 2.2 times greater. At day 5, a 2-fold increase was found, and at day 8 there was no significant difference in values. Furthermore, after delivery of the cells into tendon, fluorescence readings for the samples (n = 19) showed 9450 compared with the positive control at 21,218. At 96 hours the mean was 27,609 compared with 34,850 for the positive control. The difference in fluorescence means at 48 hours and 96 hours were significant (p < .001). Live-dead and DAPI staining confirmed the presence of live cells at the tendon repair site.
  
  
  CONCLUSIONS
  Sutures seeded with pluripotential embryonic cells deliver cells to a tendon repair site. The cells deposited at the repair site survive the trauma of passage and remain metabolically active, as seen in staining and metabolic assay studies. Use of bioactive sutures leads to repopulation of the acellular zone surrounding sutures within the tendon.
authors.affiliation: Department of Orthopaedic Surgery, Stanford University Medical Center, Palo Alto, CA 94063, USA. jyao@stanford.edu
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Yao
authors.forename: Tatiana
authors.initials: T
authors.lastname: Korotkova
authors.forename: R Lane
authors.initials: RL
authors.lastname: Smith
mesh_terms: D000125:Achilles Tendon / Q000601:surgery*; D000818:Animals; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible; D005456:Fluorescent Dyes; D007211:Indoles; D008856:Microscopy, Fluorescence; D023421:Models, Animal; D039904:Pluripotent Stem Cells / Q000637:transplantation*; D011817:Rabbits; D033581:Stem Cell Transplantation / Q000379:methods; D013536:Suture Techniques; D013537:Sutures; D013718:Tensile Strength; D020858:Tissue and Organ Harvesting
chemical_list: D020099:Coated Materials, Biocompatible; D005456:Fluorescent Dyes; D007211:Indoles; C007293:DAPI