title: Ly6C(low) and not Ly6C(high) macrophages accumulate first in the heart in a model of murine pressure-overload.
abstract: Cardiac tissue remodeling in the course of chronic left ventricular hypertrophy requires phagocytes which degrade cellular debris, initiate and maintain tissue inflammation and reorganization. The dynamics of phagocytes in left ventricular hypertrophy have not been systematically studied. Here, we characterized the temporal accumulation of leukocytes in the cardiac immune response by flow cytometry and fluorescence microscopy at day 3, 6 and 21 following transverse aortic constriction (TAC). Cardiac hypertrophy due to chronic pressure overload causes cardiac immune response and inflammation represented by an increase of immune cells at all three time points among which neutrophils reached their maximum at day 3 and macrophages at day 6. The cardiac macrophage population consisted of both Ly6C(low) and Ly6C(high) macrophages. Ly6C(low) macrophages were more abundant peaking at day 6 in response to pressure overload. During the development of cardiac hypertrophy the expression pattern of adhesion molecules was investigated by qRT-PCR and flow cytometry. CD11b, CX3CR1 and ICAM-1 determined by qRT-PCR in whole cardiac tissue were up-regulated in response to pressure overload at day 3 and 6. CD11b and CX3CR1 were significantly increased by TAC on the surface of Ly6C(low) but not on Ly6C(high) macrophages. Furthermore, ICAM-1 was up-regulated on cardiac endothelial cells. In fluorescence microscopy Ly6C(low) macrophages could be observed attached to the intra- and extra-vascular vessel-wall. Taken together, TAC induced the expression of adhesion molecules, which may explain the accumulation of Ly6C(low) macrophages in the cardiac tissue, where these cells might contribute to cardiac inflammation and remodeling in response to pressure overload.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Weisheit
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Yunyang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Anton
authors.initials: A
authors.lastname: Faron
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Odilia
authors.initials: O
authors.lastname: Köpke
authors.affiliation: Geschwister-Scholl-Gymnasium, Academic High School Daun, Daun, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Weisheit
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Arne
authors.initials: A
authors.lastname: Steinsträsser
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Stilla
authors.initials: S
authors.lastname: Frede
authors.affiliation: Institute of Physiology II, University of Bonn, Bonn, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Meyer
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Boehm
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hoeft
authors.affiliation: Institute of Experimental Immunology, University Hospital Bonn, Bonn, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kurts
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Baumgarten
mesh_terms: D000818:Animals; D006332:Cardiomegaly / Q000276:immunology* / Q000503:physiopathology; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D011312:Pressure; D060888:Real-Time Polymerase Chain Reaction