All Arteriogenesis Is Local? Home Boys Versus the Newcomers

To the Editor:The article by Khmelewski et al1 raises an important question in the field of arteriogenesis: do circulating (mononuclear) cells play a functional role during the adaptive proliferation of preexistent collateral pathways? Khmelewski et al propose that local vascular macrophages, rather than circulating monocytes, are crucial during early phases of arteriogenesis. Several important aspects, however, have not been addressed in the report by Khmelewski et al, and several other points made by the authors are contradictory to the experimental findings of others.The experimental-induced depletion of monocytes under in vivo conditions is cumbersome and error-prone. Cyclophosphamide (CY) indeed is used as a chemotherapeutic agent. However, it is also a strong …