Embryonic stem cells markers are present within rabbit atherosclerotic plaques

Abstract

Recent evidence suggests that smooth muscle cells within atherosclerotic plaques originate from vascular progenitor cells. We have previously shown that smooth muscle cells and macrophages present within rabbit atherosclerotic plaques are positive for factors of the renin angiotensin and nitric oxide systems as well as the hematopoietic stem-cell marker CD34 and the panleukocyte marker CD45. To explore the idea that these cells are of primitive types, immunohistochemistry was used to identify pluripotent embryonic stem cells (ESC) markers (Oct-4, SSEA1,3,4, TRA1-60, 81) in these plaques and to compare these to intimal thickening. Objective: To immunolocalise ESC markers in rabbit aortic intimal thickening and atherosclerotic plaques. Design: New Zealand White rabbits were fed either a control (Con) diet, 0.5% cholesterol (Chol) or 1% methionine (Meth) for 12 weeks. Animals were perfusion fixed, aortae excised and processed for paraffin. Immunohistochemistry was performed by standard techniques. Results: Oct-4, SSEA 1, 3 and 4, TRA-1-60 and TRA-1-81 were all present within in atherosclerotic plaques. However, some cells were not positive for TRA-1-60 and TRA-1-81. In fact, positive TRA-1-81 macrophages were uncommon, and positive TRA-1-81 smooth muscle cells were rare. Intimal thickening in Meth did not show any TRA-1-81 positive cells Conclusions: Macrophages and smooth muscle cells within atherosclerotic plaques express markers of ESC. These results suggest that cells within these plaques are primitive and might differentiate into other types of cells.