title: Myogenic stem cell-laden hydrogel scaffold in wound healing of the disrupted external anal sphincter.
abstract: OBJECTIVE
  To evaluate the effect of myogenic stem cell-laden hydrogel scaffold on contractile function and histomorphology of the external anal sphincter (EAS) after transection without repair.
  
  
  METHODS
  Eighty female rats underwent anal sphincter transection without repair. After 2 weeks, animals were injected at the transection site with: nothing (non-repaired control, NRC group); a polyethylene glycol-based hydrogel matrix scaffold combined with phosphate-buffered saline (PBS/hydrogel group); a hydrogel matrix scaffold combined with myogenic stem cells (stem cell/hydrogel group): or type I collagen (collagen) group. 4 (n = 40) or 12 (n = 40) weeks later, the anal sphincter complexes were dissected out and analyzed for contractile function, disruption, and striated muscle volume. Time-matched unoperated controls (UOC) were utilized for each of the two time points (n = 20).
  
  
  RESULTS
  After 4 weeks, maximal electrical field-stimulated (EFS) contractions were significantly decreased in all four non-repaired treatment groups compared with UOC. However, EFS-stimulated contractions, tetanic force generation, and twitch tension were improved in non-repaired EAS injected with stem cell/hydrogel group relative to the NRC, PBS/hydrogel, or collagen groups. NRC and sphincters injected with PBS/hydrogel deteriorated further by 12 weeks, while those receiving stem cell/hydrogel maintained improved contractile function at varying frequencies and voltages. Striated muscle volume increased from 4 to 12 weeks for PBS/hydrogel and stem cell/hydrogel animals. At 12 weeks, stem cell/hydrogel animals had greater sphincter striated muscle volumes compared with all other treatment groups.
  
  
  CONCLUSIONS
  In this animal model, sustained improvement of contractile responses in non-repaired EAS treated with biogel scaffold and myogenic stem cells suggests that a biologically compatible matrix may facilitate stem cell survival, differentiation, or function leading to recovery of contractile function even after persistent disruption.
authors: Division of Female Pelvic Medicine and Reconstructive Surgery, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9032, USA.
authors: T Ignacio
authors: TI
authors: Montoya
authors: Jesus F
authors: JF
authors: Acevedo
authors: Benjamin
authors: B
authors: Smith
authors: Patrick W
authors: PW
authors: Keller
authors: Joseph L
authors: JL
authors: Sailors
authors: Liping
authors: L
authors: Tang
authors: R Ann
authors: RA
authors: Word
authors: Clifford Y
authors: CY
authors: Wai
mesh_terms: D001003:Anal Canal / Q000293:injuries / Q000502:physiology / Q000601:surgery*; D000818:Animals; D004195:Disease Models, Animal; D004558:Electric Stimulation; D005260:Female; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009132:Muscles / Q000166:cytology; D053758:Nanoparticles; D017207:Rats, Sprague-Dawley; D033581:Stem Cell Transplantation; D054457:Tissue Scaffolds; D014945:Wound Healing / Q000502:physiology*
chemical_list: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
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