The response to oestrogen deprivation of the cartilage collagen degradation marker, CTX-II, is unique compared with other markers of collagen turnover.
BACKGROUND
The urinary level of the type II collagen degradation marker CTX-II is increased in postmenopausal women and in ovariectomised rats, suggesting that oestrogen deprivation induces cartilage breakdown. Here we investigate whether this response to oestrogen is also true for other type II collagen turnover markers known to be affected in osteoarthritis, and whether it relates to its presence in specific areas of cartilage tissue.


METHODS
The type II collagen degradation markers CTX-II and Helix-II were measured in the body fluids of premenopausal and postmenopausal women and in those of ovariectomised rats receiving oestrogen or not. Levels of PIIANP, a marker of type II collagen synthesis, were also measured in rats. Rat knee cartilage was analysed for immunoreactivity of CTX-II and PIIANP and for type II collagen expression.


RESULTS
As expected, urinary levels of CTX-II are significantly increased in postmenopausal women and also in oestrogen deprived rats, although only transiently. However, in neither case were these elevations paralleled by a significant increase of Helix-II levels and PIIANP levels did not change at any time. CTX-II immunoreactivity and collagen expression were detected indifferent cartilage areas. The upper zone is the area where CTX-II immunoreactivity and collagen expression best reflected the differences in urinary levels of CTX-II measured in response to oestrogen. However, correlations between urinary levels of CTX-II and tissue immunostainings in individual rats were not statistically significant.


CONCLUSIONS
We found only a small effect of oestrogen deprivation on cartilage. It was detected by CTX-II, but not by other type II collagen turnover markers typically affected in osteoarthritis.
Bay-Jensen
Anne-Christine
AC
Department of Clinical Cell Biology, IRS/CSFU, University of Southern Denmark, Vejle Hospital, Kabbeltoft 25, 7100 Vejle, Denmark.
Tabassi
Nadine C B
NC
Sondergaard
Lene V
LV
Andersen
Thomas L
TL
Dagnaes-Hansen
Frederik
F
Garnero
Patrick
P
Kassem
Moustapha
M
Delaissé
Jean-Marie
JM
D000328:Adult; D000368:Aged; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002356:Cartilage / Q000378:metabolism*; D024043:Collagen Type II / Q000378:metabolism*; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives; D004967:Estrogens / Q000502:physiology*; D005260:Female; D006801:Humans; D007717:Knee / Q000473:pathology; D008875:Middle Aged; D010003:Osteoarthritis / Q000378:metabolism*; D010052:Ovariectomy; D010446:Peptide Fragments / Q000378:metabolism; D017698:Postmenopause; D051381:Rats; D017207:Rats, Sprague-Dawley
D015415:Biomarkers; D024043:Collagen Type II; D004967:Estrogens; D010446:Peptide Fragments; C121824:ethylenestradiol; D004958:Estradiol