Infrared microspectroscopic determination of collagen cross-links in articular cartilage
Rieppo, L., Kokkonen, H. T., Kulmala, K. A. M., Kovanen, V., Lammi, M. J., Töyräs, J., & Saarakkala, S. (2017). Infrared microspectroscopic determination of collagen cross-links in articular cartilage. Journal of Biomedical Optics, 22 (3), 035007. doi:10.1117/1.JBO.22.3.035007
Published inJournal of Biomedical Optics
DisciplineGerontologia ja kansanterveys
© The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License.
Collagen forms an organized network in articular cartilage to give tensile stiffness to the tissue. Due to its long half-life, collagen is susceptible to cross-links caused by advanced glycation end-products. The current standard method for determination of cross-link concentrations in tissues is the destructive high-performance liquid chromatography (HPLC). The aim of this study was to analyze the cross-link concentrations nondestructively from standard unstained histological articular cartilage sections by using Fourier transform infrared (FTIR) microspectroscopy. Half of the bovine articular cartilage samples (n ¼ 27) were treated with threose to increase the collagen cross-linking while the other half (n ¼ 27) served as a control group. Partial least squares (PLS) regression with variable selection algorithms was used to predict the cross-link concentrations from the measured average FTIR spectra of the samples, and HPLC was used as the reference method for cross-link concentrations. The correlation coefficients between the PLS regression models and the biochemical reference values were r ¼ 0.84 (p < 0.001), r ¼ 0.87 (p < 0.001) and r ¼ 0.92 (p < 0.001) for hydroxylysyl pyridinoline (HP), lysyl pyridinoline (LP), and pentosidine (Pent) cross-links, respectively. The study demonstrated that FTIR microspectroscopy is a feasible method for investigating cross-link concentrations in articular cartilage. ...