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Projekt Druckansicht

Einfluss von Geschlecht auf epigenetische Veränderungen verursacht durch Nikotin im abdominalen Aortenaneurysma

Fachliche Zuordnung Herz- und Gefäßchirurgie
Förderung Förderung von 2018 bis 2020
Projektkennung Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 398906357
 
Erstellungsjahr 2020

Zusammenfassung der Projektergebnisse

Gender-dependent differences in experimental abdominal aortic aneurysm (AAA) development were studied in the context nicotine exposure. Using a novel in-vivo inhalation system, mice of both genders were exposed to e-cigarette (e-cig) vapor containing nicotine for 6 weeks on a daily basis. After AAA induction using the porcine pancreatic elastase (PPE) model, mice exposed to e-cig vapor containing nicotine developed significantly larger and faster growing AAA when compared to room airexposed control animals. This was accompanied with significant upregulation of central pro-inflammatory and vascular remodeling genes. Opposing the initially proposed hypothesis, female mice were not protected from the augmenting effects of nicotine inhalation. Results indicated that inhaled nicotine through e-cigs leads to downregulation of miR-24 and subsequent upregulation of one of it’s targets, the vascular-injury-protein CHI3L1/Chil1. Here, nicotine induced reactive oxygen species (ROS) production, which in turn regulated miR-24 and subsequent Chil1. Finally, Chil1 knockout in mice exposed to e-cig protected from the aforementioned augmenting effects, marking its central role in nicotine-augmented AAA formation in both genders. Additionally, exposure to e-cig vapor containing nicotine led to increased aortic stiffening assessed with pulse-wave velocity and ex-vivo pressure myography. Effects were pronounced in young mice, suggesting e-cig usage as a cardiovascular risk factor especially for younger populations where e-cigs a particular popular. Further, the effects of hyperlipidemia on the PPE model were studied using rAAV8- D377Y-mPcsk9 viral genomes in C57/BL6J mice and additional dietary manipulation. In difference to the Angiotensin-II model for AAA, where hyperlipidemia is essential for the model to work, increased plasma lipids did not lead to augmented AAA formation in the PPE model. This was verified in independent experiments using ApoE-knockout mice versus wildtype. Histological evaluation of AAA lesions revealed accumulated lipid in the medial layer, which correlated with plasma cholesterol. Analysis of human AAA-lesions showed similar medial lipid deposition. Despite this observation, the data suggested that elevated plasma lipids do not contribute significantly to AAA progression in the mouse PPE model.

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