Macrophage Heterogeneity: Relevance and Functional Implications in Atherosclerosis

Atherosclerosis is a chronic inflammatory disease involving many cell types with a well-accepted key role for macrophages. A wide array of different properties and functional characteristics are attributed to macrophages present in the atherosclerotic plaque. As an increasing body of evidence strengthens the consensus that macrophages comprise a heterogeneous population, several co-existing subtypes with diverse, even opposing specialties have already been described in fields like parasitology, tumour biology and metabolic disorders. However, macrophage heterogeneity within atherosclerotic lesions has not been studied in detail yet. In this review we will introduce the characteristics of macrophage subsets in other pathologies and address the presence and possible roles of distinct macrophage subtypes in the rapidly evolving field of atherosclerosis. Finally, we make an effort to relate these subtypes to disease progression and explore a number of opportunities for novel diagnostic and therapeutic approaches.