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. 2016 Oct 17;594(23):7105–7126. doi: 10.1113/JP272979

Figure 9. Effects of age and frailty on interstitial fibrosis and collagen production in the sinoatrial node .

Figure 9

A, representative images demonstrating patterns of interstitial collagen deposition (red colour) in the right atrial posterior wall (intercaval region adjacent to the crista terminalis) from young and aged hearts. B, quantification of fibrosis from histological sections as depicted in A. Data analysed using Student's t test; n = 5 young and 4 aged hearts. C, linear regression analysis of interstitial collagen in the SAN region as a function of FI (n = 9 hearts). D, effects of age on total collagen content in the right atrium by hydroxyproline assay. Data analysed using a Mann–Whitney rank sum test; n = 10 young and 10 aged hearts. E, correlation between total collagen content in the right atrium and FI (n = 20 hearts; correlation coefficient obtained using Pearson's correlation). F and G, quantitative mRNA expression of collagen I (F) and collagen III (G) in the SAN of young and aged mice. Data analysed using Student's t test; n = 9 young and 8 aged hearts. H and I, correlation between SAN expression of collagen I (H) and collagen III (I) expression and FI (n = 17 hearts; correlation coefficient obtained using Pearson's correlation).