Combined Immunoglobulin Free Light Chains Are Novel Predictors of Cardiovascular Events in Patients With Abdominal Aortic Aneurysm.

OBJECTIVE: Abdominal aortic aneurysm (AAA) is characterised by the presence of B cells and immunoglobulins in the aortic wall, mainly in the adventitia. Kappa (κ) and lambda (λ) free light chains (FLCs) are produced from B cells during immunoglobulin synthesis. This study investigated the presence and prognostic value of combined FLCs (cFLCs or summed κ and λ) in patients with AAA. METHODS: cFLCs were analysed by a turbidimetric specific assay in tissue conditioned media from AAA samples (n = 34) compared with healthy aortas (n = 34) from France and in plasma samples from patients with AAA (n = 434) and age matched controls (n = 104) selected from the Viborg Vascular (VIVA) AAA screening trial in Denmark. t test, logistic regression, and Cox regression were used to test whether plasma cFLCs serve as a marker for AAA presence and whether cFLCs were predictive of death, major adverse cardiovascular events (MACE), or major adverse lower limb events (MALE). RESULTS: Increased cFLC levels were detected in the AAA adventitial layer compared with the AAA medial layer and healthy media layer (13.65 ± 3.17 vs. 6.57 ± 1.01 vs. 0.49 ± 0.09 mg/L, respectively, p < .050). The upper tertile of plasma cFLCs was independently associated with AAA presence after correcting for confounders (odds ratio [OR] 7.596, 95% confidence intervals [CI] 3.117 - 18.513; p < .001). Of 434 patients with AAA, 89 (20.5%) died, 104 (24.0%) suffered MACE, and 63 (14.5%) suffered MALE, during a five year follow up. In univariable analysis, the cFLC upper tertile was associated with a higher risk of death, MACE, and MALE (p < .001 for all). After adjustment for confounders, cFLCs remained an independent predictor of all cause mortality (hazard ratio [HR] 4.310, 95% CI 2.157 - 8.609; p < .001), MACE (HR 2.153, 95% CI 1.218 - 3.804; p = .008), or MALE (HR 3.442, 95% CI 1.548 - 7.652; p = .002) for those in the upper tertile. CONCLUSION: Increased cFLCs are observed in adventitial tissue of patients with AAA, indicating local activation of B cells. Plasma cFLC levels are an independent predictor of death, MACE, and MALE in patients with AAA.

Protection of diabetes in aortic abdominal aneurysm: Are antidiabetics the real effectors?

Aortic aneurysms, including abdominal aortic aneurysms (AAAs), is the second most prevalent aortic disease and represents an important cause of death worldwide. AAA is a permanent dilation of the aorta on its infrarenal portion, pathologically associated with oxidative stress, proteolysis, vascular smooth muscle cell loss, immune-inflammation, and extracellular matrix remodeling and degradation. Most epidemiological studies have shown a potential protective role of diabetes mellitus (DM) on the prevalence and incidence of AAA. The effect of DM on AAA might be explained mainly by two factors: hyperglycemia [or other DM-related factors such as insulin resistance (IR)] and/or by the effect of prescribed DM drugs, which may have a direct or indirect effect on the formation and progression of AAAs. However, recent studies further support that the protective role of DM in AAA may be attributable to antidiabetic therapies (i.e.: metformin or SGLT-2 inhibitors). This review summarizes current literature on the relationship between DM and the incidence, progression, and rupture of AAAs, and discusses the potential cellular and molecular pathways that may be involved in its vascular effects. Besides, we provide a summary of current antidiabetic therapies which use could be beneficial for AAA.

Galectin-1 prevents pathological vascular remodeling in atherosclerosis and abdominal aortic aneurysm.

Pathological vascular remodeling is the underlying cause of atherosclerosis and abdominal aortic aneurysm (AAA). Here, we analyzed the role of galectin-1 (Gal-1), a ß-galactoside-binding protein, as a therapeutic target for atherosclerosis and AAA. Mice lacking Gal-1 (Lgals1-/-) developed severe atherosclerosis induced by pAAV/D377Y-mPCSK9 adenovirus and displayed higher lipid levels and lower expression of contractile markers of vascular smooth muscle cells (VSMCs) in plaques than wild-type mice. Proteomic analysis of Lgals1-/- aortas showed changes in markers of VSMC phenotypic switch and altered composition of mitochondrial proteins. Mechanistically, Gal-1 silencing resulted in increased foam cell formation and mitochondrial dysfunction in VSMCs, while treatment with recombinant Gal-1 (rGal-1) prevented these effects. Furthermore, rGal-1 treatment attenuated atherosclerosis and elastase-induced AAA, leading to higher contractile VSMCs in aortic tissues. Gal-1 expression decreased in human atheroma and AAA compared to control tissue. Thus, Gal-1-driven circuits emerge as potential therapeutic strategies in atherosclerosis and AAA.

Unbiased plasma proteomics discovery of biomarkers for improved detection of subclinical atherosclerosis.

BACKGROUND: Imaging of subclinical atherosclerosis improves cardiovascular risk prediction on top of traditional risk factors. However, cardiovascular imaging is not universally available. This work aims to identify circulating proteins that could predict subclinical atherosclerosis. METHODS: Hypothesis-free proteomics was used to analyze plasma from 444 subjects from PESA cohort study (222 with extensive atherosclerosis on imaging, and 222 matched controls) at two timepoints (three years apart) for discovery, and from 350 subjects from AWHS cohort study (175 subjects with extensive atherosclerosis on imaging and 175 matched controls) for external validation. A selected three-protein panel was further validated by immunoturbidimetry in the AWHS population and in 2999 subjects from ILERVAS cohort study. FINDINGS: PIGR, IGHA2, APOA, HPT and HEP2 were associated with subclinical atherosclerosis independently from traditional risk factors at both timepoints in the discovery and validation cohorts. Multivariate analysis rendered a potential three-protein biomarker panel, including IGHA2, APOA and HPT. Immunoturbidimetry confirmed the independent associations of these three proteins with subclinical atherosclerosis in AWHS and ILERVAS. A machine-learning model with these three proteins was able to predict subclinical atherosclerosis in ILERVAS (AUC [95%CI]:0.73 [0.70-0.74], p < 1 × 10-99), and also in the subpopulation of individuals with low cardiovascular risk according to FHS 10-year score (0.71 [0.69-0.73], p < 1 × 10-69). INTERPRETATION: Plasma levels of IGHA2, APOA and HPT are associated with subclinical atherosclerosis independently of traditional risk factors and offers potential to predict this disease. The panel could improve primary prevention strategies in areas where imaging is not available. FUNDING: This study was supported by competitive grants from the Spanish Ministry of Science, Innovation and Universities (BIO2015-67580-P, PGC2018-097019-B-I00, PID2019-106814RB-I00 and SAF2016-80843-R), through the Carlos III Institute of Health-Fondo de Investigacion Sanitaria grant PRB3 (IPT17/0019 - ISCIII-SGEFI / ERDF, ProteoRed), CIBERCV and CIBERDEM, the Fundacio MaratoTV3 (grant 122/C/2015) and "la Caixa" Banking Foundation (project HR17-00247). The PESA study is co-funded equally by the Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain, and Banco Santander, Madrid, Spain. The ILERVAS study was funded by the Diputacio de Lleida. The study also receives funding from the Instituto de Salud Carlos III (PI15/02019; PI18/00610; RD16/0009) and the FEDER funds. The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia, Innovacion y Universidades (MCNU) and the Pro CNIC Foundation.

Malondialdehyde-modified HDL particles elicit a specific IgG response in abdominal aortic aneurysm.

High Density Lipoprotein (HDL) plays a protective role in abdominal aortic aneurysm (AAA); however, recent findings suggest that oxidative modifications could lead to dysfunctional HDL in AAA. This study aimed at testing the effect of oxidized HDL on aortic lesions and humoral immune responses in a mouse model of AAA induced by elastase, and evaluating whether antibodies against modified HDL can be found in AAA patients. HDL particles were oxidized with malondialdehyde (HDL-MDA) and the changes were studied by biochemical and proteomics approaches. Experimental AAA was induced in mice by elastase perfusion and then mice were treated with HDL-MDA, HDL or vehicle for 14 days. Aortic lesions were studied by histomorphometric analysis. Levels of anti-HDL-MDA IgG antibodies were measured by an in-house immunoassay in the mouse model, in human tissue-supernatants and in plasma samples from the VIVA cohort. HDL oxidation with MDA was confirmed by enhanced susceptibility to diene formation. Proteomics demonstrated the presence of MDA adducts on Lysine residues of HDL proteins, mainly ApoA-I. MDA-modification of HDL abrogated the protective effect of HDL on cultured endothelial cells as well as on AAA dilation in mice. Exposure to HDL-MDA elicited an anti-HDL-MDA IgG response in mice. Anti-HDL-MDA were also detected in tissue-conditioned media from AAA patients, mainly in intraluminal thrombus. Higher plasma levels of anti-HDL-MDA IgG antibodies were found in AAA patients compared to controls. Anti-HDL-MDA levels were associated with smoking and were independent predictors of overall mortality in AAA patients. Overall, MDA-oxidized HDL trigger a specific humoral immune response in mice. Besides, antibodies against HDL-MDA can be detected in tissue and plasma of AAA patients, suggesting its potential use as surrogate stable biomarkers of oxidative stress in AAA.