title: Evaluation of host stem cell-derived cardiac myocytes in consecutive biopsies in long-term cardiac transplant patients.
abstract: BACKGROUND
  Bone marrow-derived stem cells are involved in tissue formation in transplanted organs. In human renal cell transplants, recipient-specific cells have been shown to participate in regeneration of interstitial tissue. In hepatic transplants, hepatocytes with a recipient sex chromosome pattern have been observed. Recruitment of stem cells in repair and regeneration of cardiac myocytes has been demonstrated in experimental ischemia. Recently, cardiac antral myocytes of recipient origin have been shown to populate transplanted hearts in gender-mismatched transplants.
  
  
  METHODS
  Using the fluorescence in situ hybridization (FISH) technique we examined serial post-transplant right ventricular biopsies and sections of ventricle (at time of autopsy) of 4 gender-mismatched female-to-male transplanted hearts (graft survival 0.5 to 10 years, mean 5.1 years) for Y chromosomes within cardiac myocytes.
  
  
  RESULTS
  We detected recipient-specific sex chromosomal patterns in single rare cardiac myocytes in 1 case in a serial biopsy after 7 years of transplant survival. The other serial biopsies, as well as the final sections at autopsy, showed no recipient pattern chromosomes within the myocytes. In addition, 2 cases demonstrated Y chromosomes in the smooth muscle of intracardiac arteries.
  
  
  CONCLUSIONS
  Development of recipient marrow-derived stem cells into functional myocytes in the ventricle of transplanted hearts is a rare feature. The higher percentage of stem cell population in the cardiac atria may be a feature of tissue repair and/or an early feature of transplant physiology. Similar to other transplant organs, recipient stem cells are involved in tissue neovascularization.
authors.affiliation: Department of Pathology, University of Pennsylvania Presbyterian Medical Center, 39th and Market Streets, Philadelphia, PA 19104, USA.
authors.forename: Franz
authors.initials: F
authors.lastname: Fogt
authors.forename: Kurt H
authors.initials: KH
authors.lastname: Beyser
authors.forename: Christopher
authors.initials: C
authors.lastname: Poremba
authors.forename: Robert L
authors.initials: RL
authors.lastname: Zimmerman
authors.forename: Josef
authors.initials: J
authors.lastname: Ruschoff
mesh_terms: D000328:Adult; D000368:Aged; D002454:Cell Differentiation / Q000235:genetics; D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D005260:Female; D006085:Graft Survival / Q000235:genetics; D016027:Heart Transplantation; D006352:Heart Ventricles / Q000473:pathology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D032383:Myocytes, Cardiac / Q000502:physiology*; D013234:Stem Cells / Q000502:physiology*