title: Extracellular matrix scaffold for cardiac repair.
abstract: BACKGROUND
  Heart failure remains a significant problem. Tissue-engineered cardiac patches offer potential to treat severe heart failure. We studied an extracellular matrix scaffold for repairing the infarcted left ventricle.
  
  
  RESULTS
  Pigs (n=42) underwent left ventricular (LV) infarction. At 6 to 8 weeks, either 4-layer multilaminate urinary bladder-derived extracellular matrix or expanded polytetrafluoroethlyene (ePTFE) was implanted as full-thickness LV wall patch replacement. At 1-week, 1-month, or 3-month intervals, pigs were terminated. After macroscopic examination, samples of tissue were prepared for histology, immunocytochemistry, and analysis of cell proportions by flow cytometry. One-week and 1-month patches were intact with thrombus and inflammation; at 1 month, there was also tissue with spindle-shaped cells in proteoglycan-rich and collagenous matrix. More alpha-smooth muscle actin-positive cells were present in urinary bladder matrix (UBM) than in ePTFE (22.2+/-3.3% versus 8.4+/-2.7%; P=0.04). At 3 months, UBM was bioresorbed, and a collagen-rich vascularized tissue with numerous myofibroblasts was present. Isolated regions of alpha-sarcomeric actin-positive, intensely alpha-smooth muscle actin-immunopositive, and striated cells were observed. ePTFE at 3 months had foreign-body response with necrosis and calcification. Flow cytometry showed similarities of cells from UBM to normal myocardium, whereas ePTFE had limited cardiomyocyte markers.
  
  
  CONCLUSIONS
  Appearance of a fibrocellular tissue that included contractile cells accompanied biodegradation of UBM when implanted as an LV-free wall infarction patch. UBM appears superior to synthetic material for cardiac patching and trends toward myocardial replacement at 3 months.
authors.affiliation: American Cardiovascular Research Institute, Norcross, GA, USA. krobinson@acrionline.org
authors.forename: Keith A
authors.initials: KA
authors.lastname: Robinson
authors.forename: Jinshen
authors.initials: J
authors.lastname: Li
authors.forename: Megumi
authors.initials: M
authors.lastname: Mathison
authors.forename: Alka
authors.initials: A
authors.lastname: Redkar
authors.forename: Jianhua
authors.initials: J
authors.lastname: Cui
authors.forename: Nicolas A F
authors.initials: NA
authors.lastname: Chronos
authors.forename: Robert G
authors.initials: RG
authors.lastname: Matheny
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Badylak
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials; D015415:Biomarkers; D005109:Extracellular Matrix / Q000637:transplantation*; D005260:Female; D005434:Flow Cytometry; D006333:Heart Failure / Q000209:etiology / Q000601:surgery*; D006352:Heart Ventricles / Q000601:surgery; D008297:Male; D008422:Materials Testing; D009203:Myocardial Infarction / Q000150:complications; D009206:Myocardium / Q000473:pathology; D011138:Polytetrafluoroethylene; D019736:Prostheses and Implants; D034421:Sus scrofa; D023822:Tissue Engineering; D001743:Urinary Bladder / Q000648:ultrastructure; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D015415:Biomarkers; D011138:Polytetrafluoroethylene