Table 2.

Selected populations of cardiac macrophages and their functions

Main function	Population of cardiac macrophages	Characteristic
Phagocytosis	MHC-IIloCCR2−	Apoptotic and necrotic cells clearance The highest level of MerTK [50]
Electrical conduction	a) MHC-IIhiCCR2hi b) MHC-IIhiCCR2lo c) MHC-IIloCCR2lo	a,b) Generation of transient electrical signals, propagation of electrical signal by Cx43-gap junction coupling with cardiomyocytes b,c) Controlling heart rhythm and the heart beat owing to expression of ion channels [56]
Vessel patrolling	Monocytes: CX3CR1hiLy6C− (mouse) CX3CR1hiCD14dimCD16+ (human)	Recognition and removal of damaged luminal cells; scavenging micrometric particles at steady-state [37, 38, 62]
Arterial tone regulation	Lyve-1+	Regulation of vascular tone and collagen production by mural cells [63]
Osmoregulation	TonEBP+	Regulation of blood pressure, extracellular fluid, and solute volume Acting via TonEBP/VEGF-C signaling pathway Mediating lymphangiogenesis [105, 106]
Proinflammatory	CCR2+MHC-IIhi (mouse) CCR2+HLA-DRhi (human) Ly6Chi CCR2+	Monocyte-derived Promote inflammatory response [41, 137, 138]; produce IL-1b, increase cardiocyte necrosis, replacement fibrosis, worsen systolic activity in acute inflammation [76]; systemic inflammation triggers CCR2+ cardiac macrophage invasion and promote interstitial collagen deposition what stiffens myocardial wall [76, 181] resulting in diastolic dysfunction
Anti-inflammatory	CCR2−MHC-IIlo/hi(mouse) CCR2−HLA-DRhi (human) Ly6Clo CCR2−	Embryonic origin Proangiogenic function Fetal coronary vessel development and maturation Reparative functions [25, 41] Wound healing Reduction of inflammation (IL-10 production) after acute phase, preservation of cardiac function; promotion of collagen deposition, fibrosis, and angiogenesis [142]
Heart valve remodeling	a) CD301b+ b) CD206+	a) Inflammation and fibrosis within the valve [148] b) Tissue repair promotion and regeneration [45]