The relationships between the degree of beta-isomerization of type I collagen degradation products in the urine and aging, menopause and osteoporosiswith fractures
H. Hoshino et al., The relationships between the degree of beta-isomerization of type I collagen degradation products in the urine and aging, menopause and osteoporosiswith fractures, OSTEOPOR IN, 9(5), 1999, pp. 405-409
We have evaluated the effect of aging, menopause and osteoporosis on the me
asurements of both nonisomerized type I collagen C-telopeptide breakdown pr
oducts (alpha-CTx) by radioimmunoassay (RIA) and beta-isomerized type I col
lagen C-telopeptide breakdown products (beta-CTx) by enzyme-linked immunoso
rbent assay (ELISA). In 86 premenopausal healthy women (PRE), 144 postmenop
ausal healthy women (POST), 74 patients with vertebral fractures (VX) and 6
1 patients with hip fractures (HX), urinary CTx excretion was measured by b
oth ELISA and RIA assays. Samples were collected more than 6 months after f
racture in the VX group and within 48 h after fracture in the HX group. In
all subjects a highly significant correlation was found between alpha-CTx a
nd beta-CTx (r = 0.85). The values of beta-CTx in the POST group greatly in
creased compared with those in the PRE group (% mean increase: 82%), while
the values of alpha-CTx in the POST group moderately increased compared wit
h those in the PRE group (% mean increase: 47%). The values of both alpha-C
Tx and beta-CTx in the HX group were significantly higher than those in the
other groups, but particularly the increase in mean alpha-CTx (211% for HX
versus POST) was very high compared with the increase in mean beta-CTx (68
% for HX versus POST). Moreover, the alpha-CTx/beta-CTx ratio in the HX gro
up was significantly higher than in the other groups. These results suggest
that both assays well reflect the increase in bone resorption associated w
ith high bone turnover, especially, in osteoporotic patients with hip fract
ure. However, there was a difference between the urinary excretion of a-CTx
and beta-CTx in patients with hip fracture, so the alpha-CTx/beta-CTx radi
o might be a good indicator reflecting the characteristics of bone metaboli
sm for osteoporosis with hip fracture.