Relative mean peak intensity of m/z 1361.7, m/z 1349.7 and m/z 1401.7. Biomap was used to quantify the differences in the peptide peak intensity of A) m/z 1361.7, C) m/z 1349.7 and E) m/z 1401.7 between young, old and OA cartilages. For m/z 1361.7 two donors representative of each group are illustrated here. Scale bar shows normalized intensities to 190 m/z matrix peak. Histogram of B) m/z 1361.7, D) m/z 1349.7 and F) m/z 1401.7 shows the means of relative peak intensities and 95% CI, n = 3, *represents P <0.05 and ***represents P <0.001. OA, osteoarthritis; 95% CI, 95% confidence interval.