Resident macrophages in the cochlear blood-labyrinth barrier and their renewal via migration of bone-marrow-derived cells.
A large population of perivascular cells was found to be present in the area of the blood-labyrinth barrier in the stria vascularis of normal adult cochlea. The cells were identified as perivascular resident macrophages (PVMs), as they were positive for several macrophage surface molecules including F4/80, CD68, and CD11b. The macrophages, which were closely associated with microvessels and structurally intertwined with endothelial cells and pericytes, constitutively expressed scavenger receptor classes A(1) and B(1) and accumulated blood-borne proteins such as horseradish peroxidase and acetylated low-density lipoprotein. The PVMs were demonstrated to proliferate slowly, as evidenced by the absence of 5-bromo-2-deoxyuridine (BrdU)-positive PVMs at 3-14 days in normal mice injected with BrdU. However, in irradiated mice, the majority of the PVMs turned over via bone-marrow-cell migration within a 10-month time-frame. The existence of PVMs in the vascular wall of the blood-labyrinth barrier might therefore serve as a source for progenitor cells for postnatal vasculogenesis and might contribute to the repair of damaged vessels in the context of a local inflammatory response.
Shi
Xiaorui
X
Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, NRC04, Portland, OR 97239, USA. shix@ohsu.edu
D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D055806:Microvessels / Q000166:cytology / Q000378:metabolism; D020286:Pericytes / Q000166:cytology / Q000378:metabolism; D013316:Stria Vascularis / Q000166:cytology / Q000378:metabolism; D013997:Time Factors
D000943:Antigens, Differentiation