Letter by Hibbert et al Regarding Article, “Smooth Muscle Cells Healing Atherosclerotic Plaque Disruptions Are of Local, Not Blood, Origin in Apolipoprotein E Knockout Mice”

Abstract

To the Editor: We congratulate Bentzon and colleagues on their interesting study of the origin of smooth muscle cells (SMCs) in atherosclerotic lesions in the context of plaque hemorrhage and mechanical disruption.1 Although their study supports the notion that SMCs originate from the vessel wall, there are significant limitations that should be addressed. In their initial experiment, apolipoprotein E knockout mice received bone marrow transplants from green fluorescent protein-positive donors and then were followed until death (mean interval, 6 months). Two major concerns arise from this experiment. First, the timeframe from transplantation to death is problematic, as marrow repopulation by endogenous cells …