title: Natural myocardial ECM patch drives cardiac progenitor based restoration even after scarring.
abstract: To evaluate the regenerative capacity of non-supplemented and bioactive patches made of decellularized porcine cardiac extracellular matrix (pcECM) and characterize the biological key factors involved in possible cardiac function (CF) restoration following acute and 8weeks chronic MI.
  
  
  
  pcECM is a key natural biomaterial that can affect cardiac regeneration following myocardial infarction (MI), through mechanisms, which are still not clearly understood.
  
  
  
  Wistar rats underwent MI and received pcECM patch (pcECM-P) treatment in either acute or chronic inflammatory phases. Treated, sham operated (no MI), and control (MI without treatment) animals, were compared through echocardiography, hemodynamics, pathological evaluation and analyses of various mRNA and protein level markers.
  
  
  
  Our results show that in both acute and long-term chronic MI models, pcECM promotes significant cardiac function improvement, which is correlated to progenitor (GATA4(+), c-kit(+)) and myocyte (MYLC(+), TRPI(+)) recruitment. Interestingly, recruited progenitors, isolated using laser capture microdissection (LCM), expressed both early and late cardiomyocyte (CM) differentiation markers, suggesting differentiation towards the CM lineage. Recruited CM-like cells organized in a partially striated and immature muscle fiber arrangement that presented connexin43 -a crucial mediator of cardiac electrical conductivity. Concomitantly, pcECM was rapidly vascularized, and induced a constructive remodeling process as indicated by increased M2/M1 macrophage phenotypic ratio and pathological evaluation.
  
  
  
  Acellular pcECM patch implants alone, i.e., without added biologics, are bioactive, and exert potent efficacy, stimulating biological regenerative processes that cooperatively lead to a cardiac progenitor-based restoration of function, even after scar tissue had already formed.
  
  
  
  MI ('heart attack') remains the leading cause of heart failure and death in developed-countries. Restoration of cardiac function requires active turnover of damaged heart contracting cells (CM), however, CM endogenous regeneration is not efficient and is a matter of controversy. We show that a bioactive biomaterial alone-decellularized heart tissue (pcECM)-without added cells or growth factors, can elicit a complex regenerative response even after irreversible scarring. The pcECM patch induces macrophage polarization towards constructive remodeling and cardiomyocyte progenitor cell (GATA4(+), c-kit(+)) recruitment (evidenced at both mRNA and protein levels) resulting in de novo immature striated-like muscle patterns (MLC(+), TrpI(+), connexin43(+)). We, therefore, suggest this bioactive pcECM can model cardiac regeneration, and serve as a candidate for fast-track clinical application.
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Udi
authors.initials: U
authors.lastname: Sarig
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Hadar
authors.initials: H
authors.lastname: Sarig
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Elio
authors.initials: E
authors.lastname: de-Berardinis
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Su-Yin
authors.initials: SY
authors.lastname: Chaw
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Evelyne B V
authors.initials: EBV
authors.lastname: Nguyen
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore.
authors.forename: Vaibavi S
authors.initials: VS
authors.lastname: Ramanujam
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore.
authors.forename: Vu D
authors.initials: VD
authors.lastname: Thang
authors.affiliation: Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore 138673, Singapore.
authors.forename: Muthafar
authors.initials: M
authors.lastname: Al-Haddawi
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Susan
authors.initials: S
authors.lastname: Liao
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; Faculty of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Dror
authors.initials: D
authors.lastname: Seliktar
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Kofidis
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Freddy Y C
authors.initials: FYC
authors.lastname: Boey
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore. Electronic address: assubbu@ntu.edu.sg.
authors.forename: Subbu S
authors.initials: SS
authors.lastname: Venkatraman
authors.affiliation: School of Materials and Science Engineering, Nanyang Technological University, Singapore 639798, Singapore; Faculty of Biotechnology and Food Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: machlufm@tx.technion.ac.il.
authors.forename: Marcelle
authors.initials: M
authors.lastname: Machluf
mesh_terms: D000818:Animals; D002452:Cell Count; D002921:Cicatrix / Q000473:pathology*; D005109:Extracellular Matrix / Q000378:metabolism*; D006439:Hemodynamics; D020007:Implants, Experimental; D008264:Macrophages / Q000473:pathology; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D018919:Neovascularization, Physiologic; D017208:Rats, Wistar; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology*; D034421:Sus scrofa
keywords: Bioactive patch; Cardiac progenitors; Extracellular matrix; Heart regeneration; Myocardial infarction; Tissue engineering