title: Remodeling of the mononuclear phagocyte network underlies chronic inflammation and disease progression in heart failure: critical importance of the cardiosplenic axis.
abstract: BACKGROUND
  The role of mononuclear phagocytes in chronic heart failure (HF) is unknown.
  
  
  OBJECTIVE
  Our aim was to delineate monocyte, macrophage, and dendritic cell trafficking in HF and define the contribution of the spleen to cardiac remodeling.
  
  
  RESULTS
  We evaluated C57Bl/6 mice with chronic HF 8 weeks after coronary ligation. As compared with sham-operated controls, HF mice exhibited: (1) increased proinflammatory CD11b+ F4/80+ CD206- macrophages and CD11b+ F4/80+ Gr-1(hi) monocytes in the heart and peripheral blood, respectively, and reduced CD11b+ F4/80+ Gr-1(hi) monocytes in the spleen; (2) significantly increased CD11c+ B220- classical dendritic cells and CD11c+ low)B220+ plasmacytoid dendritic cells in both the heart and spleen, and increased classic dendritic cells and plasmacytoid dendritic cells in peripheral blood and bone marrow, respectively; (3) increased CD4+ helper and CD8+ cytotoxic T-cells in the spleen; and (4) profound splenic remodeling with abundant white pulp follicles, markedly increased size of the marginal zone and germinal centers, and increased expression of alarmins. Splenectomy in mice with established HF reversed pathological cardiac remodeling and inflammation. Splenocytes adoptively transferred from mice with HF, but not from sham-operated mice, homed to the heart and induced long-term left ventricular dilatation, dysfunction, and fibrosis in naive recipients. Recipient mice also exhibited monocyte activation and splenic remodeling similar to HF mice.
  
  
  CONCLUSIONS
  Activation of mononuclear phagocytes is central to the progression of cardiac remodeling in HF, and heightened antigen processing in the spleen plays a critical role in this process. Splenocytes (presumably splenic monocytes and dendritic cells) promote immune-mediated injurious responses in the failing heart and retain this memory on adoptive transfer.
authors.affiliation: From the Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham and Birmingham VAMC, Birmingham, AL (M.A.I., T.H., S.S.S., B.P., S.D.P.); and Department of Medicine, University of Louisville, KY (J.R.K.).
authors.forename: Mohamed Ameen
authors.initials: MA
authors.lastname: Ismahil
authors.forename: Tariq
authors.initials: T
authors.lastname: Hamid
authors.forename: Shyam S
authors.initials: SS
authors.lastname: Bansal
authors.forename: Bindiya
authors.initials: B
authors.lastname: Patel
authors.forename: Justin R
authors.initials: JR
authors.lastname: Kingery
authors.forename: Sumanth D
authors.initials: SD
authors.lastname: Prabhu
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D017951:Antigen Presentation; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D002633:Chemotaxis; D002908:Chronic Disease; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D004195:Disease Models, Animal; D006333:Heart Failure / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D007249:Inflammation / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D009206:Myocardium / Q000276:immunology* / Q000378:metabolism; D010586:Phagocytes / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D015398:Signal Transduction; D013154:Spleen / Q000276:immunology* / Q000378:metabolism; D013156:Splenectomy; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D013997:Time Factors; D020257:Ventricular Remodeling
chemical_list: D015415:Biomarkers; D016207:Cytokines; D018836:Inflammation Mediators
keywords: dendritic cells; heart failure; inflammation; monocytes; spleen