title: Intramyocardial transplantation of cardiac mesenchymal stem cells reduces myocarditis in a model of chronic Chagas disease cardiomyopathy.
abstract: BACKGROUND
  New therapeutic options are necessary for patients with chronic Chagas disease, a leading cause of heart failure in Latin American countries. Stem cell therapy focused on improving cardiac function is a promising approach for treating heart disease. Here, we evaluated the therapeutic effects of cardiac mesenchymal stem cells (CMSCs) in a mouse model of chronic Chagas disease.
  
  
  METHODS
  CMSCs were isolated from green fluorescent protein (GFP) transgenic C57BL/6 mouse hearts and tested for adipogenic, osteogenic, chondrogenic, endothelial, and cardiogenic differentiation potentials evaluated by histochemical and immunofluorescence techniques. A lymphoproliferation assay was performed to evaluate the immunomodulatory activity of CMSCs. To investigate the therapeutic potential of CMSCs, C57BL/6 mice chronically infected with Trypanosoma cruzi were treated with 106 CMSCs or saline (control) by echocardiography-guided injection into the left ventricle wall. All animals were submitted to cardiac histopathological and immunofluorescence analysis in heart sections from chagasic mice. Analysis by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was performed in the heart to evaluate the expression of cytokines involved in the inflammatory response.
  
  
  RESULTS
  CMSCs demonstrated adipogenic, osteogenic, and chondrogenic differentiation potentials. Moreover, these cells expressed endothelial cell and cardiomyocyte features upon defined stimulation culture conditions and displayed immunosuppressive activity in vitro. After intramyocardial injection, GFP+ CMSCs were observed in heart sections of chagasic mice one week later; however, no observed GFP+ cells co-expressed troponin T or connexin-43. Histopathological analysis revealed that CMSC-treated mice had a significantly decreased number of inflammatory cells, but no reduction in fibrotic area, two months after treatment. Analysis by qRT-PCR demonstrated that cell therapy significantly decreased tumor necrosis factor-alpha expression and increased transforming growth factor-beta in heart samples.
  
  
  CONCLUSIONS
  We conclude that the CMSCs exert a protective effect in chronic chagasic cardiomyopathy primarily through immunomodulation.
authors.forename: Daniela Nascimento
authors.initials: DN
authors.lastname: Silva
authors.forename: Bruno Solano
authors.initials: BS
authors.lastname: de Freitas Souza
authors.forename: Carine Machado
authors.initials: CM
authors.lastname: Azevedo
authors.forename: Juliana Fraga
authors.initials: JF
authors.lastname: Vasconcelos
authors.forename: Rejane Hughes
authors.initials: RH
authors.lastname: Carvalho
authors.forename: Milena Botelho Pereira
authors.initials: MB
authors.lastname: Soares
authors.forename: Ricardo Ribeiro
authors.initials: RR
authors.lastname: Dos Santos
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002598:Chagas Cardiomyopathy / Q000628:therapy*; D018031:Connexin 43 / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000032:analysis; D056747:Immunomodulation; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009205:Myocarditis; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D020107:Troponin T / Q000378:metabolism; D014349:Trypanosoma cruzi; D014409:Tumor Necrosis Factor-alpha
chemical_list: D018031:Connexin 43; C543076:GJA1 protein, mouse; D020107:Troponin T; D014409:Tumor Necrosis Factor-alpha; D049452:Green Fluorescent Proteins