Relationship between biochemical markers of bone turnover and bone scintigraphic indices in assessment of Paget's disease activity.
OBJECTIVE
To evaluate the relationship between biochemical markers of bone turnover and bone scan indices of disease activity, as well as to analyze their variations based on skeletal involvement, in Paget's disease.


METHODS
Serum samples were obtained from 51 patients with Paget's disease to determine the levels of total alkaline phosphatase (total AP), bone alkaline phosphatase (bone AP), propeptide carboxyterminal of type I procollagen (PICP), propeptide aminoterminal of type I procollagen (PINP), osteocalcin, tartrate-resistant acid phosphatase, and telopeptide carboxyterminal of type I collagen. Urine samples were analyzed for levels of hydroxyproline (HYP), pyridinoline (PYR), deoxypyridinoline (DPYR), C-terminal telopeptide of type I collagen (CTx), and N-terminal telopeptide of type I collagen (NTx). In addition, 2 semiquantitative scintigraphic indices, disease activity (AI) and disease extent (EI), were obtained. Pagetic skeletal locations were evaluated individually, with special attention to skull involvement.


RESULTS
All biochemical markers correlated with the AI and the EI. Serum PINP, bone AP, and total AP showed the highest proportions of increased values among the bone formation markers (94%, 82%, and 76%, respectively). Among the bone resorption markers, urinary NTx showed the highest proportion of increased values in patients with Paget's disease (96%), compared with PYR (69%), DPYR (71%), CTx (65%), and HYP (64%). In patients with mild disease activity, serum PINP was the marker with the highest proportion of increased values (71%). In contrast, serum PICP and urinary CTx were the most discriminative markers for skull involvement. Except for higher values for most of the biochemical markers of bone turnover in flat bones, no major differences in other skeletal locations were observed.


CONCLUSIONS
The determination of serum PINP as a marker of bone formation and urinary NTx as a marker of bone resorption provided the best biochemical profile to ascertain the extent and activity of Paget's disease. In patients with skull involvement, serum PICP and urinary CTx were shown to be the most discriminative markers.
Alvarez
L
L
Bioquímica Clínica, Hospital Clínic i Provincial, University of Barcelona, Spain.
Peris
P
P
Pons
F
F
Guañabens
N
N
Herranz
R
R
Monegal
A
A
Bedini
J L
JL
Deulofeu
R
R
Martínez de Osaba
M J
MJ
Muñoz-Gómez
J
J
Ballesta
A M
AM
D000135:Acid Phosphatase / Q000097:blood; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D001862:Bone Resorption; D001842:Bone and Bones / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000378:metabolism*; D003094:Collagen / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010001:Osteitis Deformans / Q000097:blood / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015675:Osteocalcin / Q000097:blood; D011877:Radionuclide Imaging; D013644:Tartrates / Q000494:pharmacology
D015415:Biomarkers; D013644:Tartrates; D015675:Osteocalcin; D003094:Collagen; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; C029768:tartaric acid