Cathepsin K predicts femoral neck bone mineral density change in nonosteoporotic peri- and early postmenopausal women.
OBJECTIVE
Cathepsin K is a cysteine protease that plays an essential role in organic bone matrix degradation. The aim of our study was to seek correlation of serum cathepsin K levels and a change in bone mineral density (BMD) over a 3-year period in a population of healthy nonosteoporotic women. The secondary end points were the correlations of serum cathepsin K with cross-sectional BMD and with other serum bone turnover markers and age.


METHODS
In 43 healthy women aged 42 to 57 years, blood samples for determination of cathepsin K, osteocalcin, bone alkaline phosphatase, C-terminal cross-linking telopeptide of type I collagen, osteoprotegerin, and nuclear factor kappaB ligand were collected at the time of the first BMD measurement. BMD measurements were repeated after 3 years.


RESULTS
We found a moderate negative correlation of serum cathepsin K levels with change in femoral neck BMD, but none with change in spinal BMD. There were no significant correlations between cross-sectional BMD of the spine or femoral neck and serum levels of cathepsin K. Serum levels of cathepsin K were not significantly correlated with any bone turnover markers studied or with age.


CONCLUSIONS
Serum cathepsin K does not seem to represent a surrogate for bone turnover markers used at present, but it might be useful as a predictor of cortical bone loss.
Prezelj
Janez
J
Department of Endocrinology and Metabolic Diseases, Biomedica Group, Vienna, Austria.
Ostanek
Barbara
B
Logar
Darja Bitenc
DB
Marc
Janja
J
Hawa
Gerhard
G
Kocjan
Tomas
T
D000328:Adult; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000502:physiology*; D016723:Bone Remodeling / Q000502:physiology; D056657:Cathepsin K; D002403:Cathepsins / Q000097:blood*; D024042:Collagen Type I / Q000097:blood; D005260:Female; D005272:Femur Neck / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D053244:Osteoprotegerin / Q000097:blood; D010455:Peptides / Q000097:blood; D047648:Perimenopause / Q000502:physiology*; D017698:Postmenopause / Q000502:physiology*; D053245:RANK Ligand / Q000097:blood
D015415:Biomarkers; D024042:Collagen Type I; D053244:Osteoprotegerin; D010455:Peptides; D053245:RANK Ligand; C505688:TNFSF11 protein, human; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D002403:Cathepsins; C534130:CTSK protein, human; D056657:Cathepsin K