https://doi.org/10.1007/s00392-025-02625-4
1Uniklinik Köln Experimentelle Kardiologie/ Innere Med. III Köln, Deutschland; 2Universitätsklinikum Köln Klinik III für Innere Medizin - Experimentelle Kardiologie Köln, Deutschland; 3Universitätsklinikum Düsseldorf Klinik für Gefäß- und Endovaskularchirurgie Düsseldorf, Deutschland; 4Universitätsklinikum Bonn Molekulare Kardiologie // Geb. 370 Bonn, Deutschland; 5Herzzentrum der Universität zu Köln Klinik III für Innere Medizin Köln, Deutschland; 6Herzzentrum der Universität zu Köln Klinik für Kardiologie, Angiologie, Pneumologie und Internistische Intensivmedizin Köln, Deutschland
Background: The abdominal aortic aneurysm (AAA) is a multifactorial disease with a high prevalence in individuals over 65 years of age, associated with significant mortality and morbidity. There is no pharmacological approach that directly targets AAA, and surgery remains the only treatment option. The nitrated fatty acid NO2-OA is formed endogenously and has no known side effects. NO2-OA is a highly pleiotropic compound that exhibits anti-inflammatory, antioxidative, and anti-fibrotic effects through direct and indirect interactions with various signaling pathways. In this study, we explored NO2-OA as a potential pharmacological treatment for AAA in mice.
Methods: AAA was induced in wildtype (wt) mice via surgery. The abdominal aorta was ligated, blood flow interrupted and filled with porcine-pancreas-elastase (PPE) for five minutes. Mice were treated with NO2-OA for 6 days to assess acute inflammation or 4 weeks for tissue remodeling and fibrosis. A control group was treated with polytethylenglycol (PEG). Treatment was administered via Alzet mini osmotic pumps, starting 3 days before (prophylactic) or after (therapeutic) AAA induction. Ultrasounds were performed to monitor surgery effects, aneurysm induction and growth. Aortas were snap-frozen for proteomics or embedded for histological analysis, stained for collagen, elastin, CD45/CD68, ROS, MMP-activity and a-SMA.
Results: In both the prophylactic and therapeutic settings, the AAA diameter in NO2-OA-treated mice was significantly smaller after 28 days of treatment (p=0.042; p<0.001) compared to the control group. In the prophylactic setting, elastin grading (p=0.023) and the number of smooth muscle cells (p=0.046) in NO2-OA-treated mice were significantly higher as compared to PEG treated animals. In the therapeutic setting, NO2-OA-treated mice showed significantly lower immune cell recruitment, as indicated by CD45 (p=0.018) and CD68 (p=0.028) staining. Additionally, NO2-OA-treated mice exhibited significantly lower MMP activity (p=0.049) and reduced ROS activity (p=0.046) after 28 days. They also showed significantly higher amounts of elastin (p=0.006) compared to the control group. Proteomic analysis identified significant upregulation of immunoglobulins IGHG3 and IGHG2B, along with increased lipid transport activity (LMF1 and TMLHE) in NO2-OA-treated mice. These findings suggest that enhanced antigen binding and receptor binding activities play a key role in the beneficial effects of NO2-OA in AAA disease.
Conclusions: We have shown that NO2-OA is a promising pharmacological treatment option in both prophylactic and therapeutic AAA mouse models. The anti-oxidative, anti-inflammatory, and anti-fibrotic effects of NO2-OA help maintain aortic wall stability, reduce immune cell recruitment and preserve the balance in aortic wall remodeling processes. Although proteomics analysis has already revealed the upregulation of certain proteins involved in the immune response, the underlying signaling pathways are not yet fully understood and require further investigation.