Mehrkens, DennisDohr, JohannesNettersheim, Felix SebastianBallmann, FelixBastigkeit, JilBrückner, AlexanderGeissen, SimonDe Vore, LaurenFitsch, CedricDiekmann, Chrisde la Fuente-Alonso, AndreaSchelemei, PatrikPicard, Felix RubenKochen, MalteArkenberg, PerRappenecker, AnnaAhdab, MaysamNemade, HarshalNarayan, SuchitraBraumann, SimonKreuzberg, WiebkeHof, AlexanderGuthoff, HenningMensah, Benedicta QuayeLechner, SebastianGuala, AndreaEvangelista, ArturTeixido-Tura, GiselaNistal, J FranciscoCampanero, Miguel RKaemmerer, HaraldWolf, ZsuzsannaHoldenrieder, StefanGroenink, Maartenvan Andel, MitziMieremet, ArnoutPfeiler, SusanneGerdes, NorbertFlögel, UlrichZimmermann, Laura-MariaSengle, GerhardEich, Marie-LisaSchömig-Markiefka, BirgidAdam, MattiFleischmann, Bernd KWenzel, DanielaRedondo, Juan Miguelde Waard, VivianKlinke, AnnaBaldus, StephanMollenhauer, MartinWinkels, Holger2026-01-212026-01-212025-12-17Cardiovasc Res. 2025 Dec 17:cvaf248https://hdl.handle.net/20.500.12105/27162Patients suffering from Marfan syndrome (MFS), the most prevalent inherited connective tissue disorder, face premature mortality due to dissection and rupture of thoracic aortic aneurysms. Here, we questioned whether myeloperoxidase (MPO), a leucocyte-derived enzyme with high affinity to the vessel wall, contributes to aortic remodelling in MFS. Plasma MPO levels were evaluated in MFS patients and healthy controls. Thoracic aortic aneurysm formation was determined in heterozygous transgenic Fbn1C1041G/+ (MFS) mice, MPO-deficient MFS mice (MFSxMpo-/-), and MFS mice treated with an MPO inhibitor by ultrasound and histology.MFS patients exhibited increased circulating MPO levels and marked aortic MPO deposition. In MFS mice, MPO-deficiency reduced aortic elastin fragmentation and aneurysm formation. RNA sequencing revealed an inflammatory gene program in aortic endothelial cells isolated from MFS mice in comparison to WT and MFSxMpo-/- mice. This was accompanied by enhanced endothelial expression of the leucocyte adhesion molecule ICAM-1, increased leucocyte adhesion, and, consequently, leucocyte infiltration in MFS aortae. Moreover, MPO directly contributed to adverse extracellular matrix remodelling through overproduction of reactive oxygen species and subsequent vascular protein modifications leading to enhanced matrix metalloproteinase 2/9 activity. Lastly, treatment of MFS mice with the orally available MPO inhibitor AZM198 attenuated TAA formation. MPO is increased in MFS and contributes to thoracic aortic dilatation by inducing inflammatory endothelial activation, oxidative stress, and adverse extracellular matrix remodelling. Pharmacological and genetic inhibition of MPO reduced MFS-related aortic dilation in mice, highlighting MPO as a promising therapeutic target in MFS.This work was supported by the Deutsche Forschungsgemeinschaft (GRK 2407 [360043781] to H.W.; SFB TRR259 [397484323] project A04 to H.W. and S.B, project A05 to N.G., project C01 to B.F., project B01 to D.W. and B.F., project B03 and B08 to U.F., project B05 to M.A., project B09 to G.S., project C03 to M.M., and MO 3438/2-1 to M.M.); the Center for Molecular Medicine Cologne, the Neven-DuMont Foundation to H.W.; and the Koeln Fortune Program (363/2020 to F.S.N; 248/2021 to A.H.). Further funding was received from La Caixa Banking Foundation under project codes HR18-00068 (to M.R.C. and J.M.R.); and projects PID2020-115217RB-I00 and PID2021-122388OB-I00 (to M.R.C and J.M.R, respectively) funded by MCIN/AEI/10.13039/501100011033; and funds from the Instituto de Salud Carlos III (CIBER-CV CB16/11/00264).engNAhttp://creativecommons.org/licenses/by-nc-nd/4.0/Marfan syndromeAortic aneurysmInflammationMyeloperoxidaseEndothelial cellsAttribution-NonCommercial-NoDerivatives 4.0 International41403006Cardiovascular Researchembargoed access