Multiple molecular forms of pyridinolines cross-links excreted in human urine evaluated by chromatographic and immunoassay methods.
The measurement of the collagen cross-links, hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP), excreted in urine either in free or peptide-bound forms represents the most extensively investigated biochemical marker of bone collagen degradation. We studied the urinary molecular forms of pyridinolines after separation in free and peptide-linked fractions by chromatography and serial dialysis. The pyridinoline amounts of molecular species (free, < 1000 D, 1000-3500 D, 3500-10,000 D, and > 10,000 D) were evaluated by high performance liquid chromatography (HPLC) as well as with the two newly introduced enzyme-linked immunosorbent assay (ELISA) methods for determination of free pyridinolines (collagen Pyrilinks and collagen Pyrilinks-D). The variability of urinary pyridinoline forms were studied in healthy adult control subjects (n = 10, 38.4 +/- 7.5) years), in adolescents (n = 10, 16 +/- 3.3 years), and in elderly subjects with vitamin D insufficiency (n = 10, 87.3 +/- 4.3 years). Free and peptide-conjugated pyridinolines with MW < 1000 D constitute the major part of urinary cross-links in all groups, with a significantly lesser excretion in elderly patients than in adolescent groups. Expressed as a percent of total cross-links, urinary free pyridinolines assessed by direct HPLC are less in elderly subjects (HP = 34.2 +/- 6.2%, LP = 32.7 +/- 7.6%) than in adolescents (HP = 45.8 +/- 10.8%, p = 0.0065 and LP = 47.8 +/- 12.1%, p = 0.012) and in healthy adults (HP = 39.3 +/- 11.5%, NS and LP = 38.1 +/- 9.3%, NS).(ABSTRACT TRUNCATED AT 250 WORDS)
Kamel
S
S
Laboratoire de pharmacie clinique, Faculté de pharmacie, Amiens, France.
Brazier
M
M
Neri
V
V
Picard
C
C
Samson
L
L
Desmet
G
G
Sebert
J L
JL
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000596:Amino Acids / Q000302:isolation & purification / Q000652:urine*; D001862:Bone Resorption / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013223:Statistics as Topic
D000596:Amino Acids; C015484:pyridinoline; C036020:deoxypyridinoline