Distribution of smooth muscle cells and macrophages expressing scavenger receptor BI/II in atherosclerosis.
OBJECTIVE
Scavenger receptors type I and II (SRBI/II) have dual roles in both atherogenic and antiatherogenic functions through interactions with lipoproteins and their expression in macrophages; how-ever, the distribution and density of SRBI/II-positive macrophages and smooth muscle cells (SMCs) as well as their association with lipid metabolism-related proteins in atherosclerotic intima of the human aorta remain unclear.


METHODS
Autopsied aortic tissues were double-immunostained with SRBI/BII and smooth muscle actin or macrophage-specific antibodies. The density of SRBI/BII-positive SMCs and macrophages in intimal lesion was measured. They were also immunostained with antibodies against four apolipoproteins, four phospholipase A2s, and CETP.


RESULTS
SRBI/II was expressed in both macrophages and SMCs distributed in various intimal lesions. The density of SRBI/II-positive SMCs in intimal lesions significantly decreased with the advance of atherosclerosis, whereas the density of SRBI/II-positive macrophages significantly increased with atherosclerotic development. In addition, functional proteins, such as apolipoproteins, secretory phospholipase A2s, and CETP, were distributed in the intimal stroma around SRBI/II-positive cells in all lesion types.


CONCLUSIONS
The results indicated that SMCs are involved in lipid metabolism via SRBI/II expression mainly in the early stages of atherosclerosis evolution, and that SRBI/II-positive macrophages are mainly involved in advanced stages.
Ishikawa
Yukio
Y
Department of Pathology, Toho University School of Medicine, Tokyo, Japan. yukio@med.toho-u.ac.jp
Kimura-Matsumoto
Masayo
M
Murakami
Makoto
M
Murakami
Makoto
M
Yamamoto
Kei
K
Akasaka
Yoshikiyo
Y
Uzuki
Miwa
M
Yuri
Yuri
Y
Inomata
Naomi
N
Yokoo
Tomoko
T
Ishii
Toshiharu
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000473:pathology; D001053:Apolipoproteins / Q000378:metabolism; D050197:Atherosclerosis / Q000473:pathology*; D001344:Autopsy; D005260:Female; D006801:Humans; D051907:Lysosomal Membrane Proteins / Q000096:biosynthesis*; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D051116:Receptors, Scavenger / Q000096:biosynthesis*; D051122:Scavenger Receptors, Class B / Q000096:biosynthesis*
D001053:Apolipoproteins; D051907:Lysosomal Membrane Proteins; D051116:Receptors, Scavenger; C495124:SCARB1 protein, human; C074299:SCARB2 protein, human; D051122:Scavenger Receptors, Class B