Making a Difference: Monocyte Heterogeneity in Cardiovascular Disease

Monocytes are frequently described as bone marrow-derived precursors of macrophages. Although many studies support this view, we now appreciate that monocytes neither develop exclusively in the bone marrow nor give rise to all macrophages and dendritic cells. In addition to differentiating to specific leukocyte populations, monocytes, as monocytes, are functionally and ontogenically heterogeneous. In this review we will focus on the development and activity of monocytes and their subsets in mice (Ly-6 C-high/low) and humans (CD14(+/dim/-) CD16(+/-)) in the context of atherosclerosis and its complications.