Elastin- and collagen-rich human carotid plaques have increased levels of the cysteine protease inhibitor cystatin C.
BACKGROUND
Cystatin C is a major inhibitor of the elastin- and collagen-degrading cysteine proteases and may therefore have an important role in preserving atherosclerotic plaque stability. In this study we analyzed the associations between human carotid plaque cystatin C expression and the plaque content of collagen and elastin.


METHODS
Thirty-one plaques were removed by endarterectomy and homogenized. Cystatin C levels were analyzed by densitometry of Western blots and elastin and collagen levels were determined colorimetrically.


RESULTS
The plaque content of cystatin C correlated with total elastin (r = 0.58, p = 0.001) and collagen (r = 0.50, p = 0.004), as well as with cross-linked forms of elastin (r = 0.42, p = 0.022) and collagen (r = 0.52, p = 0.003). Immunohistochemical analysis demonstrated that cystatin C colocalized with elastin and collagen. No correlation was seen between cystatin C and the amount of degraded elastin or collagen in plaques.


CONCLUSIONS
The positive correlation between cystatin C levels and collagen and elastin levels in plaques supports the notion that cystatin C plays an important role in maintaining atherosclerotic plaque stability.
Gonçalves
Isabel
I
Department of Clinical Sciences, Experimental Cardiovascular Research Unit, Lund University, Malmo University Hospital, Malmo, Sweden.
Ares
Mikko P S
MP
Moberg
Anna
A
Moses
Jonatan
J
To
Fong
F
Montan
Jonathan
J
Pedro
Luís M
LM
Dias
Nuno
N
Fernandes E Fernandes
José
J
Fredrikson
Gunilla Nordin
GN
Nilsson
Jan
J
Jovinge
Stefan
S
Bengtsson
Eva
E
D000368:Aged; D015153:Blotting, Western; D002339:Carotid Arteries / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D002340:Carotid Artery Diseases / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D003094:Collagen / Q000032:analysis*; D003124:Colorimetry; D055316:Cystatin C; D015891:Cystatins / Q000032:analysis*; D004549:Elastin / Q000032:analysis*; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged
C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D003094:Collagen; D004549:Elastin