VTN and PAI-1 expression in whole blood and retinal tissue. Linear regression models were applied to analyze the relationship of VTN and PAI-1 mRNA gene expression in (A) whole blood and (B) retinal tissue. The 556 whole blood samples were derived from European donors in the GTEx dataset and underwent several normalization steps, as described in [20,21]. The analysis in retina was based on 311 healthy retina samples, as described in [22]. (C) Gene expression of 357 whole blood samples retrieved from donors below the age of 60 and 199 samples from individuals at or over 60 years of age. VTN and PAI-1 were significantly upregulated in the older cohort. (D) Similar effects, although less pronounced, were obtained in gene expression analyses of retinal tissues. (Mann–Whitney U test, * p< 0.05, **p < 0.01, *** p < 0.001).