Urinary excretion of pyridinium cross-links of collagen in infancy.
This cross-sectional study evaluated urinary excretion of pyridinium cross-links of collagen, specific markers of ongoing bone resorption, in infants aged 1 week to 7 months and examined the relationship between urinary cross-links and individual renal function. Spot urines from a total of 100 infants were analyzed. The collagen cross-links, pyridinoline (Pyd) and deoxypyridinoline (D-Pyd), were assayed by fluorescence detection after high-performance liquid chromatography (HPLC). Beta2-Microglobulin (beta2M), an index of renal tubular function, was determined by radioimmunoassay. In healthy term infants, urinary collagen cross-links were several times higher than the reported data for older children, with peak values seen at 1 month of age. Excretion of Pyd and D-Pyd was also markedly elevated in 1-month-old preterm infants, despite poor somatic growth. Such high excretion of collagen cross-links probably reflects the state of accelerated bone turnover in infancy. The postnatal change in the cross-links was different from that in urinary beta2M, and the values obtained did not correlate with beta2M in either term or preterm infants. These results indicate that cross-link excretion is not influenced directly by individual renal function.
Tsukahara
H
H
Department of Pediatrics, Fukui Medical School, Japan.
Miura
M
M
Hori
C
C
Hiraoka
M
M
Nosaka
K
K
Hata
K
K
Konishi
Y
Y
Sudo
M
M
D000596:Amino Acids / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D003094:Collagen / Q000378:metabolism / Q000652:urine*; D003430:Cross-Sectional Studies; D005260:Female; D005470:Fluorometry; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010621:Phenazopyridine / Q000378:metabolism / Q000652:urine*; D011863:Radioimmunoassay; D001613:beta 2-Microglobulin / Q000652:urine
D000596:Amino Acids; D001613:beta 2-Microglobulin; C015484:pyridinoline; C036020:deoxypyridinoline; D003094:Collagen; D010621:Phenazopyridine