Potential mechanism for recruitment and migration of CD133 positive cells to areas of vascular inflammation

Objective: Mast cells are found in large numbers in atherosclerotic plaques. The present study was conducted to determine whether tryptase stimulation of human coronary artery endothelial cells (HCAEC) would lead to an increase in transmigration of CD133 positive cells (CD133+). In vitro these cells can differentiate into mast cells under the influence of specific cytokines and growth factors. Methods and Results: CD133+ cells were isolated from umbilical cord blood. They express mRNA for several adhesion molecules that are also utilized in neutrophil migration and can migrate across an HCAEC monotayer. Migration increased significantly when HCAEC were stimulated with tryptase and decreased when CD133+ cells were pretreated with CV3988, a platelet activating factor receptor (PTAFR) antagonist. Following long-term cell culture, these cells stained positively for the presence of tryptase, a mast cell enzyme. Conclusion: CD133+ cells can be utilized as a mast cell precursor population. The transendothetial. migration is facilitated by the presence of tryptase and may utilize the PAF/PTAFR interaction in a manner similar to that involved in neutrophil transmigration. Following transmigration, a subset of these progenitor cells may mature into mast cells in the subendothelial space and play a role in propagation of the inflammatory process in atherosclerosis. (c) 2008 Elsevier Ltd. All rights reserved.