title: Cardiac tissue slice transplantation as a model to assess tissue-engineered graft thickness, survival, and function.
abstract: BACKGROUND
  Cell therapies offer the potential to improve cardiac function after myocardial infarction. Although injection of single-cell suspensions has proven safe, cell retention and survival rates are low. Tissue-engineered grafts allow cell delivery with minimal initial cell loss and mechanical support to the heart. However, graft performance cannot be easily compared, and optimal construct thickness, vascularization, and survival kinetics are unknown.
  
  
  RESULTS
  Cardiac tissue slices (CTS) were generated by sectioning mouse hearts (n=40) expressing firefly luciferase and green fluorescent protein into slices of defined size and thickness using a vibrating blade microtome. Bioluminescence imaging of CTS transplanted onto hearts of immunodeficient mice demonstrated survival of ≤30% of transplanted cells. Cardiac slice perfusion was re-established within 3 days, likely through anastomosis of pre-existing vessels with the host vasculature and invasion of vessels from the host. Immunofluorescence showed a peak in cell death 3 days after transplantation and a gradual decline thereafter. MRI revealed preservation of contractile function and an improved ejection fraction 1 month after transplantation of CTS (28±2% CTS versus 22±2% control; P=0.05). Importantly, this effect was specific to CTS because transplantation of skeletal muscle tissue slices led to faster dilative remodeling and higher animal mortality.
  
  
  CONCLUSIONS
  In summary, this is the first study to use CTS as a benchmark to validate and model tissue-engineered graft studies. CTS transplantation improved cell survival, established reperfusion, and enhanced cardiac function after myocardial infarction. These findings also confirm that dilative remodeling can be attenuated by topical transplantation of CTS but not skeletal muscle tissue grafts.
authors.affiliation: From the Department of Medicine, Division of Cardiology and Department of Radiology, Stanford Cardiovascular Institute (J.R., Q.S., J.C.W.), Department of Biochemistry (A.G.), and Department of Cardiothoracic Surgery (J.D.G.), Stanford University School of Medicine, CA.
authors.forename: Johannes
authors.initials: J
authors.lastname: Riegler
authors.affiliation: From the Department of Medicine, Division of Cardiology and Department of Radiology, Stanford Cardiovascular Institute (J.R., Q.S., J.C.W.), Department of Biochemistry (A.G.), and Department of Cardiothoracic Surgery (J.D.G.), Stanford University School of Medicine, CA.
authors.forename: Astrid
authors.initials: A
authors.lastname: Gillich
authors.affiliation: From the Department of Medicine, Division of Cardiology and Department of Radiology, Stanford Cardiovascular Institute (J.R., Q.S., J.C.W.), Department of Biochemistry (A.G.), and Department of Cardiothoracic Surgery (J.D.G.), Stanford University School of Medicine, CA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Shen
authors.affiliation: From the Department of Medicine, Division of Cardiology and Department of Radiology, Stanford Cardiovascular Institute (J.R., Q.S., J.C.W.), Department of Biochemistry (A.G.), and Department of Cardiothoracic Surgery (J.D.G.), Stanford University School of Medicine, CA.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Gold
authors.affiliation: From the Department of Medicine, Division of Cardiology and Department of Radiology, Stanford Cardiovascular Institute (J.R., Q.S., J.C.W.), Department of Biochemistry (A.G.), and Department of Cardiothoracic Surgery (J.D.G.), Stanford University School of Medicine, CA. joewu@stanford.edu.
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Wu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D053595:Embryonic Stem Cells / Q000637:transplantation*; D005260:Female; D017930:Genes, Reporter; D006085:Graft Survival; D049452:Green Fluorescent Proteins / Q000235:genetics; D006352:Heart Ventricles / Q000637:transplantation*; D006801:Humans; D049409:Luciferases, Firefly / Q000235:genetics; D008279:Magnetic Resonance Imaging; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008822:Mice, Transgenic; D023421:Models, Animal; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000601:surgery*; D009929:Organ Size; D052097:Quadriceps Muscle; D011897:Random Allocation; D023822:Tissue Engineering; D016378:Tissue Transplantation / Q000379:methods*
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D049409:Luciferases, Firefly
keywords: cell transplantation; magnetic resonance imaging; myocardial infarction; tissue engineering