Alteration of elastin, collagen and their cross-links in abdominal aortic aneurysms.
OBJECTIVE
although the mechanism of arterial dilation and aneurysm development has not been clarified, the degradation of elastin and collagen plays undoubtedly a critical role. We evaluated the elastin and collagen content through the detection of their cross-links in aneurysmal and non-aneurysmal abdominal aortic walls.


METHODS
in 26 human abdominal aortic aneurysm specimens obtained during surgery and in 24 autopsy control samples of non-aneurysmal abdominal aorta the tissue content of elastin and collagen cross-links were measured by HPLC. Collagen was also detected by evaluating two characteristic amino acids, 4-hydroxyproline (4-hypro) with a colorimetric method and 5-hydroxylysine (5-hylys) by gas chromatography.


RESULTS
significantly fewer elastin cross-links were found in aneurysm samples compared to controls (desmosines and isodesmosines: 90% reduction; p<0.01). The opposite was true for pyridinoline collagen cross-links (350% increase) and deoxypyridinolines (100% increase, p=0.01). Tissue content of 5-hylys, 4-hypro and total amino acids were reduced significantly by 50% in aneurysmal samples.


CONCLUSIONS
beside confirming decreased elastin content in aneurysmal walls, these results show a concurrent increase of collagen cross-links. Since total collagen markers were decreased (decreased 4-hypro and 5-hylys) it is reasonable to suggest that in aneurysmal aortic walls old collagen accumulates cross-links while new collagen biosynthesis is somehow defective.
Carmo
M
M
Department of Vascular Surgery, S. Carlo Borromeo Hospital, University of Milan, Italy.
Colombo
L
L
Bruno
A
A
Corsi
F R M
FR
Roncoroni
L
L
Cuttin
M S
MS
Radice
F
F
Mussini
E
E
Settembrini
P G
PG
D000368:Aged; D001012:Aorta, Abdominal / Q000737:chemistry; D017544:Aortic Aneurysm, Abdominal / Q000378:metabolism* / Q000503:physiopathology; D002851:Chromatography, High Pressure Liquid; D003094:Collagen / Q000032:analysis / Q000378:metabolism*; D004549:Elastin / Q000032:analysis / Q000378:metabolism*; D005260:Female; D006801:Humans; D006901:Hydroxylysine / Q000032:analysis; D006909:Hydroxyproline / Q000032:analysis; D066298:In Vitro Techniques; D008297:Male; D011726:Pyridinium Compounds / Q000032:analysis
D011726:Pyridinium Compounds; D006901:Hydroxylysine; D003094:Collagen; D004549:Elastin; D006909:Hydroxyproline