title: Engineered myocardial tissues constructed in vivo using cardiomyocyte-like cells derived from bone marrow mesenchymal stem cells in rats.
abstract: BACKGROUND
  To explore the feasibility of constructing engineered myocardial tissues (EMTs) in vivo, using polylactic acid -co-glycolic acid (PLGA) for scaffold and cardiomyocyte-like cells derived from bone marrow mesenchymal stem cells (BMMSCs) for seeded cells.
  
  
  METHODS
  BMMSCs were isolated from femur and tibia of Sprague-Dawley (SD) rats by density-gradient centrifugation. The third passage cells were treated with 10 μmol/L 5-azacytidine (5-aza) and 0.1 μmol/L angiotensin II (Ang II) for 24 h, followed by culturing in complete medium for 3 weeks to differentiated into cardiomyocyte-like cells. The cardiomyocyte-like cells were seeded into PLGA scaffolds to form the grafts. The grafts were cultured in the incubator for three days and then implanted into the peritoneal cavity of SD rats. Four weeks later, routine hematoxylin-eosin (HE) staining, immunohistochemical staining for myocardium-specific cardiac troponin I (cTnI), scanning electron microscopy and transmission electron microscopy were used to analyze the morphology and microconstruction of the EMTs in host rats.
  
  
  RESULTS
  HE staining showed that the cardiomyocyte-like cells distributed equally in the PLGA scaffold, and the nuclei arranged in the spindle shape. Immunohistochemical staining revealed that majority of engrafted cells in the PLGA -Cardiomyocyte-like cells group were positive for cTnI. Scanning electron microscopy showed that the inoculated cells well attached to PLGA and grew in 3 dimensions in construct. Transmission electron microscopy showed that the EMTs contained well arranged myofilaments paralleled to the longitudinal cell axis, the cells were rich in endoplasmic reticulum and mitochondria, while desmosomes, gap junction and Z line-like substances were also can be observed as well within the engrafted cells.
  
  
  CONCLUSIONS
  We have developed an in vivo method to construct engineered myocardial tissue. The in vivo microenvironment helped engrafted cells/tissue survive and share similarities with the native heart tissue.
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Xing
authors.forename: Anlin
authors.initials: A
authors.lastname: Lv
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Xuebo
authors.initials: X
authors.lastname: Yan
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Feng
authors.initials: F
authors.lastname: Cao
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001374:Azacitidine / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology*; D018929:Cell Culture Techniques / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004801:Eosine Yellowish-(YS) / Q000737:chemistry; D006416:Hematoxylin / Q000737:chemistry; D007150:Immunohistochemistry; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D008567:Membranes, Artificial; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D023421:Models, Animal; D009206:Myocardium / Q000166:cytology*; D032383:Myocytes, Cardiac / Q000166:cytology*; D011091:Polyesters; D011100:Polyglycolic Acid / Q000378:metabolism; D011108:Polymers / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering / Q000379:methods*; D019210:Troponin I / Q000032:analysis; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D008567:Membranes, Artificial; D011091:Polyesters; D011108:Polymers; D019210:Troponin I; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide); D001374:Azacitidine; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin