title: Periurethral muscle-derived mononuclear cell injection improves urethral sphincter restoration in rats.
abstract: OBJECTIVE
  Investigate the effect of a novel cell-based therapy with skeletal muscle-derived mononuclear cells (SMDMCs) in a rat model of stress urinary incontinence.
  
  
  METHODS
  Male Wistar-Kyoto rats' hind limb muscles were enzymatically dissociated, and SMDMCs were isolated without needing expansion. The cell population was characterized. Twenty female rats underwent urethrolysis. One week later, 10 rats received periurethral injection of 106cells (SMDMC group), and 10 rats received saline injections (Saline group). Ten rats underwent sham surgery (Sham group). Four weeks after injection, animals were euthanized and the urethra was removed. The incorporation of SMDMCs in the female urethra was evaluated with fluorescence in situ hybridization for the detection of Y-chromosomes. Hematoxylin and eosin, Masson's trichrome staining, and immunohistochemistry for actin and myosin were performed. The muscle/connective tissue, actin and myosin ratios were calculated. Morphological evaluation of the urethral diameters and fractional areas of the lumen, mucosa, and muscular layer was performed.
  
  
  RESULTS
  SMDMCs population was consistent with the presence of muscle cells, muscle satellite cells, perivascular cells, muscle progenitor cells, and endothelial cells. SMDMCs were incorporated into the urethra. A significant decrease in the muscle/connective tissue ratio was observed in the Saline group compared with the SMDMC and Sham groups. The proportions of actin and myosin were significantly decreased in the Saline group. No differences were observed in the morphometric parameters.
  
  
  CONCLUSIONS
  SDMSC were incorporated into the rat urethra and promoted histological recovery of the damaged urethral sphincter, resulting in decreased connective tissue deposition and increased muscle content.
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Marcelo Pitelli
authors.identifier: http://orcid.org/0000-0002-5246-1496
authors.initials: MP
authors.lastname: Turco
authors.affiliation: School of Veterinary Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Alex Balduino
authors.initials: AB
authors.lastname: de Souza
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Isida
authors.initials: I
authors.lastname: de Campos Sousa
authors.affiliation: School of Veterinary Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Paula
authors.initials: P
authors.lastname: Fratini
authors.affiliation: Department of Pathology, School of Medicine, University of São Paulo, Sao Paulo, Brazil.
authors.forename: Mariana Matera
authors.initials: MM
authors.lastname: Veras
authors.affiliation: School of Veterinary Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Marcio Nogueira
authors.initials: MN
authors.lastname: Rodrigues
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: de Bessa
authors.affiliation: School of Veterinary Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Marina Pandolphi
authors.initials: MP
authors.lastname: Brolio
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Katia Ramos Moreira
authors.initials: KRM
authors.lastname: Leite
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Homero
authors.initials: H
authors.lastname: Bruschini
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Miguel
authors.initials: M
authors.lastname: Srougi
authors.affiliation: School of Veterinary Medicine, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Maria Angélica
authors.initials: MA
authors.lastname: Miglino
authors.affiliation: Division of Urology, University of Sao Paulo School of Medicine, Sao Paulo, Brazil.
authors.forename: Cristiano Mendes
authors.initials: CM
authors.lastname: Gomes
mesh_terms: D000818:Animals; D064987:Cell- and Tissue-Based Therapy / Q000379:methods*; D005260:Female; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016896:Treatment Outcome; D014521:Urethra / Q000502:physiology; D014550:Urinary Incontinence, Stress / Q000628:therapy*
keywords: cellular therapy; mononuclear cells; muscle cells; muscle regeneration; stem cell; urethral sphincter insufficiency; urinary incontinence