A. Bruel et H. Oxlund, CHANGES IN BIOMECHANICAL PROPERTIES, COMPOSITION OF COLLAGEN AND ELASTIN, AND ADVANCED GLYCATION ENDPRODUCTS OF THE RAT AORTA IN RELATION TO AGE, Atherosclerosis, 127(2), 1996, pp. 155-165
During ageing and senescence the aorta becomes stiffer and its elastic
ity is reduced. The mechanism causing this increased stiffness of the
aortic wall was studied using a rat model. Ring-shaped samples were pr
epared from the thoracic aorta of three groups of rats aged 4.5, 14 an
d 27 months, representing young, adult and old animals. Analysis of th
e static biomechanical properties showed increased diameter (2.20 +/-
0.03 mm) and increased stiffness (4.0 +/- 0.2 mN) of aortic samples fr
om old rats compared with adult rats (1.82 +/- 0.02 mm and 3.0 +/- 0.1
mN, respectively). The total hydroxyproline and elastin content per s
ample was not changed. However, the hydroxyproline content/mm(2) of th
e aortic wall was reduced by 20% and the elastin content/mm(2) of the
aortic wall was reduced by 19% comparing the old with the adult rats.
No differences were found in the pyridinoline concentrations between o
ld and adult rats. The collagen- and elastin-associated fluorescence w
as determined as a marker of advanced glycation endproducts (AGE). Bot
h parameters were increased in the old rats compared with the adult ra
ts, by 42% and 17%, respectively, and positively correlated with stiff
ness at physiological loads. A positive correlation between collagen-a
ssociated fluorescence and maximum stiffness was found as well. In con
clusion, the age-related increase in stiffness of the aorta was associ
ated with increased diameter, reduced collagen and elastin contents/mm
(2) of the aortic wall, increased fenestration of elastic laminae and
accumulation of fluorescent material in collagen and elastin.