Figure 2.

Characterization of vascular alterations in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infected hamster lungs. Vascular alterations including endothelial hypertrophy (A–C), endothelialitis (D–F), and vasculitis (G–I) were quantified using hematoxylin and eosin (H&E) staining. All three vascular features could be detected in SARS-CoV-2 infected animals at 1 day post-infection (dpi) and were resolved at 14 dpi. Statistical analyses revealed a significant increase of endothelial hypertrophy, endothelialitis, and vasculitis in SARS-CoV-2 infected hamsters at 3 compared to 1 dpi as well as a significant decrease in pathological alterations until 14 dpi (B,E,H). The stacked bar charts represent the percentage of inflamed vessels separated according to their size (C,F,I). Small and medium-sized vessels were especially affected in high numbers and proportions. Furthermore, the number of small vessels affected by endothelial hypertrophy, endothelialitis, and vasculitis increased from 1 dpi to 3 dpi. Data are shown as box and whisker plots with mean and quartiles or as a stacked bar chart, respectively. Significant differences between mock and infected animals obtained by Mann–Whitney U tests and between dpi obtained by Kruskal–Wallis tests, followed by Dunn–Bonferroni post hoc testing are indicated by * (* p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001). Representative images of vessels were taken at 400× magnification, bars represent 50 µm.