title: Regression of cardiac hypertrophy by granulocyte colony-stimulating factor-stimulated interleukin-1β synthesis.
abstract: OBJECTIVE
  Aortic stenosis causes cardiac hypertrophy and fibrosis, which often persists despite pressure unloading after aortic valve replacement. The persistence of myocardial fibrosis in particular leads to impaired cardiac function and increased mortality. We investigated whether granulocyte colony-stimulating factor (G-CSF) beneficially influences cardiac remodelling after pressure unloading.
  
  
  RESULTS
  Left ventricular hypertrophy was induced by transverse aortic constriction in C57bl6 mice followed by debanding after 8 weeks. This model closely mimics aortic stenosis and subsequent aortic valve replacement. After debanding, mice were treated with either G-CSF or saline injection. Granulocyte colony-stimulating factor treatment significantly improved systolic (ejection fraction 70.48 ± 1.17 vs. 58.41 ± 1.56%, P < 0.001) and diastolic (E/E' 26.0 ± 1.0 vs. 32.6 ± 0.8, P < 0.05) function. Furthermore, cardiac fibrosis was significantly reduced in G-CSF-treated mice (collagen-I area fraction 7.96 ± 0.47 vs. 11.64 ± 1.22%, P < 0.05; collagen-III area fraction 10.73 ± 0.99 vs. 18.46 ± 0.71%, P < 0.001). Direct effects of G-CSF on cardiac fibroblasts or a relevant transdifferentiation of mobilized bone marrow cells could be excluded. However, a considerable infiltration of neutrophils was observed in G-CSF-treated mice. This sterile inflammation was accompanied by a selective release of interleukin-1 β (IL-1β) in the absence of other proinflammatory cytokines. In vitro experiments confirmed an increased expression of IL-1β in neutrophils after G-CSF treatment. Interleukin-1β directly induced the expression of the gelatinases matrix metalloproteinase-2 (MMP-2) and MMP-9 in cardiac fibroblasts thereby providing the regression of cardiac fibrosis.
  
  
  CONCLUSIONS
  Granulocyte colony-stimulating factor treatment improves the cardiac function and leads to the regression of myocardial fibrosis after pressure unloading. These findings reveal a previously unknown mechanism of fibrosis regression. Granulocyte colony-stimulating factor might be a potential pharmacological treatment approach for patients suffering from congestive heart failure after aortic valve replacement, although further basic research and clinical trials are required in order to prove beneficial effects of G-CSF in the human organism.
authors: Department of Cardiology,  Kerckhoff Heart and Thorax Center, Benekestrasse 2-8, D-61231 Bad Nauheim,  Germany.
authors: Sebastian
authors: S
authors: Szardien
authors: Holger M
authors: HM
authors: Nef
authors: Sandra
authors: S
authors: Voss
authors: Christian
authors: C
authors: Troidl
authors: Christoph
authors: C
authors: Liebetrau
authors: Jedrzej
authors: J
authors: Hoffmann
authors: Maximilian
authors: M
authors: Rauch
authors: Katharina
authors: K
authors: Mayer
authors: Kathrin
authors: K
authors: Kimmich
authors: Andreas
authors: A
authors: Rolf
authors: Johannes
authors: J
authors: Rixe
authors: Kerstin
authors: K
authors: Troidl
authors: Baktybek
authors: B
authors: Kojonazarov
authors: Ralph T
authors: RT
authors: Schermuly
authors: Sawa
authors: S
authors: Kostin
authors: Albrecht
authors: A
authors: Elsässer
authors: Christian W
authors: CW
authors: Hamm
authors: Helge
authors: H
authors: Möllmann
mesh_terms: D000818:Animals; D001011:Aorta; D001024:Aortic Valve Stenosis / Q000150:complications / Q000503:physiopathology; D001854:Bone Marrow Cells / Q000166:cytology; D054338:Cell Transdifferentiation; D003250:Constriction; D005260:Female; D005355:Fibrosis / Q000188:drug therapy / Q000503:physiopathology; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D017379:Hypertrophy, Left Ventricular / Q000188:drug therapy* / Q000503:physiopathology; D053583:Interleukin-1beta / Q000096:biosynthesis*; D051379:Mice; D008810:Mice, Inbred C57BL; D009206:Myocardium / Q000473:pathology*; D013318:Stroke Volume / Q000502:physiology; D015854:Up-Regulation; D020257:Ventricular Remodeling / Q000187:drug effects
chemical_list: D053583:Interleukin-1beta; D016179:Granulocyte Colony-Stimulating Factor