Interleukin-12 and -23 blockade mitigates elastase-induced abdominal aortic aneurysm

Figure 1. Transient elastase perfusion induces AAA. Mice were transiently perfused with elastase on day 0 and increase in aortic diameter (AD) was measured immediately post-perfusion, and on day 7 or day 14. Elastase perfusion resulted in ∼70% increase in AD on day 0 (post perfusion). AAA was defined as an increase in AD of greater than 100% on day 14 compared with the AD measured prior to elastase perfusion. AAA is expressed as the increase in AD in mm (A) or % (B). AAA was accompanied by elastic fiber degradation on day 14 (C). Scale bar = 250 um.

Figure 2. Macrophage expansion during AAA development. Mice were transiently perfused with elastase on day 0 and their aortas were harvested on days 3, 7, and 14. Aortic sections were stained for macrophages (MOMA-2) (A), TNF-α (B), IL12p40) (C), and MMP-9 (D). Scale bar 100 um. Values represent mean ± SEM, n = 6–8 aortas per time point. Values represent mean ± SEM, n = 6–8 aortas time point. ***p < 0.001.

Figure 3. Antagonism of IL-12p40/IL-23p19 attenuates AAA development. Mice were perfused with elastase on day 0 and injected with anti-IL-12p40 or anti-IL-23p19 or isotype control (250ug) on days 3 and 8. AD was assessed on day 14. AAA is expressed as the % increase in AD (A,C) or the change in AD in mm (B,D). Values represent mean ± SEM, n = 7–8 mice per treatment. **p < 0.01, ***p < 0.001.

Figure 4. IL-23p19 blockade suppresses macrophage polarization. (A) Aortic sections obtained on day14 were double-stained for MOMA-2 (red) and IL12p40 (green) for M1 and CD206 (green) for M2. DAPI (blue) stained nuclei. Arrows indicate co-localization (yellow). Photographs are representative of 6–8 aortas per treatment. Scale bar = 25 um. (B) Enumeration of M1/M2 on day 14. Values represent mean ± SEM, n = 6–8 mice per treatment. **p < 0.01, ***p < 0.001.

Figure 5. IL-23p19 blockade suppresses MMP activity and apoptotic cell death. Aortic sections obtained on day 14 were used to detect gelatinolytic activity of MMP by in situ zymography (A) apoptotic cells (TUNEL+, B), cell proliferation (PCNA+, C). Scale bar = 50 um (A, B), 100 um (C). Values represent mean ± SEM, n = 4–6 sections per aorta, 6–8 aortas per treatment. *P < 0.05, **P < 0.001.

Figure 6. IL-12/IL-23 in human AAA tissues. Immunohistochemistry of human AAA tissues revealed abundant expression of IL-12p40 and IL-23p19 (orange) throughout all layers of aortic wall tissue. Normal aortic wall tissue showed no specific staining. N = 3 independent AAA samples. L = lumen. Scale bar = 200 um.