Letter to the Editor |
Department of Cardiology, University of Bonn, Bonn, Germany, Gerhard.Bauriedel@ukb.uni-bonn.de
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
To the Editor:
We read with great interest the study by Ziegelhoeffer et al,1 who tested whether circulating bone marrowderived cells incorporate into collateral arteries after femoral artery ligation. Although the investigators did not find any incorporation of bone marrowderived cells in the endothelium and tunica media of growing vessels, they observed accumulations of bone marrowderived cells in areas of collateral artery growth and capillary growth and identified these cells as fibroblasts, pericytes, and primarily leukocytes. These exciting data add another piece of evidence to the concept that apparently not mural, tissue-resident cells but other cell types play a more central role in vascular repair.
Given the diversity of blood leukocyte populations, the exact identity of these cells deserves careful consideration. In this context, we recently identified dendritic cells as a novel neointimal cell type and demonstrated their maximal frequency during early neointima formation after rat carotid balloon injury.2 In another study, we also showed bone marrow and neural crestderived cells within human in-stent restenosis atherectomy samples.3 Herein, dendritic cells constituted the major mononuclear lesional cell type, whereas monocytes/macrophages were confined to areas adjacent to stent struts.3 It is tempting to speculate that dendritic cells may have contributed to the bone marrowderived perivascular leukocyte populations described by Ziegelhoeffer et al.1 Because most dendritic cells are thought to originate from hematopoietic stem cells and to share initial differentiation steps with monocytes,4 we also would like to suggest that further studies on vascular repair should evaluate the presence of specific subpopulations of
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