Characterization of the paracrine effects of human skeletal myoblasts transplanted in infarcted myocardium.
BACKGROUND
The discrepancy between the functional improvements yielded experimentally by skeletal myoblasts (SM) transplanted in infarcted myocardium and the paucity of their long-term engraftment has raised the hypothesis of cell-mediated paracrine mechanisms.


RESULTS
We analyzed gene expression and growth factors released by undifferentiated human SM (CD56(+)), myotubes (SM cultured until confluence) and fibroblasts-like cells (CD56(-)). Gene expression revealed up-regulation of pro-angiogenic (PGF), anti-apoptotics (BAG-1, BCL-2), heart development (TNNT2, TNNC1) and extracellular matrix remodelling (MMP-2, MMP-7) genes in SM. In line with the gene expression profile, the analysis of culture supernatants of SM by ELISA identified the release of growth factors involved in angiogenesis (VEGF, PIGF, angiogenin, angiopoietin, HGF and PDGF-BB) as well as proteases involved in matrix remodelling (MMP2, MMP9 and MMP10) and their inhibitors (TIMPs). Culture of smooth muscle cells (SMC), cardiomyocytes (HL-1) and human umbilical vein endothelial cells (HUVECs) with SM-released conditioned media demonstrated an increased proliferation of HUVEC, SMC and cardiomyocytes (p<0.05) and a decrease in apoptosis of cardiomyocytes (p<0.05). Analysis of nude rats transplanted with human SM demonstrated expression of human-specific MMP-2, TNNI3, CNN3, PGF, TNNT2, PAX7, TGF-beta, and IGF-1 1 month after transplant.


CONCLUSIONS
Our data support the paracrine hypothesis whereby myoblast-secreted factors may contribute to the beneficial effects of myogenic cell transplantation in infarcted myocardium.
Perez-Ilzarbe
Maitane
M
Hematology, Cardiology and Cell Therapy, Clínica Universitaria and Division of Cancer, Foundation for Applied Medical Research, Division of Cancer, University of Navarra, Pamplona, Spain.
Agbulut
Onnik
O
Pelacho
Beatriz
B
Ciorba
Cristina
C
San Jose-Eneriz
Edurne
E
Desnos
Michel
M
Hagège
Albert A
AA
Aranda
Pablo
P
Andreu
Enrique J
EJ
Menasché
Philippe
P
Prósper
Felipe
F
D000818:Animals; D017209:Apoptosis; D001706:Biopsy; D049109:Cell Proliferation; D017690:Cell Transplantation / Q000379:methods*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation; D017261:Glycosylphosphatidylinositols; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000235:genetics; D020783:Matrix Metalloproteinase 7 / Q000096:biosynthesis / Q000235:genetics; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D032448:Myoblasts, Skeletal / Q000166:cytology / Q000378:metabolism / Q000637:transplantation*; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000473:pathology; D018919:Neovascularization, Physiologic / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D019899:Paracrine Communication / Q000502:physiology*; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics; D051381:Rats; D011923:Rats, Nude; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D016896:Treatment Outcome; D019210:Troponin I / Q000096:biosynthesis / Q000235:genetics
C091732:BCL2-associated athanogene 1 protein; D004268:DNA-Binding Proteins; D017261:Glycosylphosphatidylinositols; D008565:Membrane Proteins; C098069:PIGF protein, human; C518658:TNNI2 protein, human; D014157:Transcription Factors; D019210:Troponin I; D012313:RNA; D020783:Matrix Metalloproteinase 7; D020778:Matrix Metalloproteinase 2