Spectroscopic characterization of collagen cross-links in bone.
Collagen is the most abundant protein of the organic matrix in mineralizing tissues. One of its most critical properties is its cross-linking pattern. The intermolecular cross-linking provides the fibrillar matrices with mechanical properties such as tensile strength and viscoelasticity. In this study, Fourier transform infrared (FTIR) spectroscopy and FTIR imaging (FTIRI) analyses were performed in a series of biochemically characterized samples including purified collagen cross-linked peptides, demineralized bovine bone collagen from animals of different ages, collagen from vitamin B6-deficient chick homogenized bone and their age- and sex-matched controls, and histologically stained thin sections from normal human iliac crest biopsy specimens. One region of the FTIR spectrum of particular interest (the amide I spectral region) was resolved into its underlying components. Of these components, the relative percent area ratio of two subbands at approximately 1660 cm(-1) and approximately 1690 cm(-1) was related to collagen cross-links that are abundant in mineralized tissues (i.e., pyridinoline [Pyr] and dehydrodihydroxylysinonorleucine [deH-DHLNL]). This study shows that it is feasible to monitor Pyr and DHLNL collagen cross-links spatial distribution in mineralized tissues. The spectroscopic parameter established in this study may be used in FTIRI analyses, thus enabling the calculation of relative Pyr/DHLNL amounts in thin (approximately 5 microm) calcified tissue sections with a spatial resolution of approximately 7 microm.
Paschalis
E P
EP
Mineralized Tissues Section, Hospital for Special Surgery, New York, New York 10021, USA.
Verdelis
K
K
Doty
S B
SB
Boskey
A L
AL
Mendelsohn
R
R
Yamauchi
M
M
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D002417:Cattle; D002645:Chickens; D003094:Collagen / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004151:Dipeptides / Q000378:metabolism*; D006801:Humans; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
D000596:Amino Acids; D003432:Cross-Linking Reagents; D004151:Dipeptides; C007428:5,5'-dihydroxylysylnorleucine; C010991:delta-hydroxylysylnorleucine; C015484:pyridinoline; C036020:deoxypyridinoline; D003094:Collagen