Background and aims: Lipids play an important role in atherosclerotic plaque development and are interesting candidate predictive biomarkers. However, the link between circulating lipids,... Show moreBackground and aims: Lipids play an important role in atherosclerotic plaque development and are interesting candidate predictive biomarkers. However, the link between circulating lipids, accumulating lipids in the vessel wall, and plaque destabilization processes in humans remains largely unknown. This study aims to provide new insights into the role of lipids in atherosclerosis using lipidomics and mass spectrometry imaging to investigate lipid signatures in advanced human carotid plaque and plasma samples. Methods: We used lipidomics and desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to investigate lipid signatures of advanced human carotid plaque and plasma obtained from patients who underwent carotid endarterectomy (n = 14 out of 17 whose plaque samples were analyzed by DESI-MSI). Multivariate data analysis and unsupervised clustering were applied to identify lipids that were the most discriminative species between different patterns in plaque and plasma. These patterns were interpreted by quantitative comparison with conventional histology. Results: Lipidomics detected more than 300 lipid species in plasma and plaque, with markedly different relative abundances. DESI-MSI visualized the spatial distribution of 611 lipid-related m/z features in plaques, of which 330 m/z features could be assigned based on exact mass, comparison to the lipidomic data, and high mass resolution MSI. Matching spatial lipid patterns to histological areas of interest revealed several molecular species that were colocalized with pertinent disease processes in plaque including specific sphingomyelin and ceramide species with calcification, phospholipids and free fatty acids with inflammation, and triacylglycerols and phosphatidylinositols with fibrin-rich areas. Conclusions: By comparing lipid species in plaque and plasma, we identified those circulating species that were also prominently present in plaque. Quantitative comparison of lipid spectral patterns with histology revealed the presence of specific lipid species in destabilized plaque areas, corroborating previous in vitro and animal studies. Show less
Atherosclerosis is a progressive disease resulting in the formation of an arterial plaque. Despite lipid lowering, recurrent cardiovascular events remain a risk. While atherosclerosis is primarily... Show moreAtherosclerosis is a progressive disease resulting in the formation of an arterial plaque. Despite lipid lowering, recurrent cardiovascular events remain a risk. While atherosclerosis is primarily lipid-driven, the immune system plays a critical role in the pathophysiology. Additional treatment could be achieved via immunomodulation. We aimed to identify potential biomarkers for monitoring of immunomodulatory drugs in future clinical trials and investigated pharmacological modulation of atherogenic pathways. We identified smokers and elderly healthy people as suitable groups for future clinical trials. We investigated the impact of sample aging on LPS responses, and optimized methodology for evaluation of LPS-driven neutrophil responses, in vitro and in vivo. As potential anti-atherogenic strategy, we evaluated the effect of pneumococcal vaccination on circulating oxLDL-IgM levels in man. The immunomodulatory impact of hydroxychloroquine, a drug with potential anti-atherogenic effects, was evaluated in healthy volunteers. A novel OX40L inhibitor was tested in healthy volunteers, since the OX40-OX40L axis may play a role in atherogenesis. OX40L inhibition was safe and effectively reduced T cell activity. Lastly, we showed that PD-1 agonism reduced atherosclerosis in Ldlr-/- mice. This thesis adds to the future development of effective and specific immunomodulatory treatments for atherosclerosis. Show less
This thesis investigated how coronary CT, a non-invasive imaging technique, can be used in clinical practice to better characterize coronary artery calcification and to improve risk stratification.... Show moreThis thesis investigated how coronary CT, a non-invasive imaging technique, can be used in clinical practice to better characterize coronary artery calcification and to improve risk stratification. We looked at sex-differences in the development of atherosclerosis and the differences in risks of a possible event. Development of atherosclerosis started 12 years later in women, but when both sexes have severe arteriosclerosis, women have a higher chance of an event (myocardial infarction and/or death). Furthermore, with serial coronary CT scans and detailed quantification of atherosclerosis, we analyzed which patients are more likely to have progression of atherosclerosis, despite the use of a statin (cholesterol lowering agent). Growth of plaque is associated with worse outcomes and these patients might benefit from a different and/or more aggressive treatment. Furthermore, measurement of the pericoronary adipose tissue has been postulated as a new biomarker to detect inflammation of the coronary arteries, which plays an important role in the formation and progression of atherosclerosis, and in this thesis we have attempted to establish reference values. Show less
Intravascular ultrasound (IVUS) is recommended in guiding coronary intervention. The segmentation of coronary lumen and external elastic membrane (EEM) borders in IVUS images is a key step, but the... Show moreIntravascular ultrasound (IVUS) is recommended in guiding coronary intervention. The segmentation of coronary lumen and external elastic membrane (EEM) borders in IVUS images is a key step, but the manual process is time-consuming and error-prone, and suffers from inter-observer variability. In this paper, we propose a novel perceptual organisation-aware selective transformer framework that can achieve accurate and robust segmentation of the vessel walls in IVUS images. In this framework, temporal context-based feature encoders extract efficient motion features of vessels. Then, a perceptual organisation-aware selective transformer module is proposed to extract accurate boundary information, supervised by a dedicated boundary loss. The obtained EEM and lumen segmentation results will be fused in a temporal constraining and fusion module, to determine the most likely correct boundaries with robustness to morphology. Our proposed methods are extensively evaluated in non-selected IVUS sequences, including normal, bifurcated, and calcified vessels with shadow artifacts. The results show that the proposed methods outperform the state-of-the-art, with a Jaccard measure of 0.92 for lumen and 0.94 for EEM on the IVUS 2011 open challenge dataset. This work has been integrated into a software QCU-CMS1 to automatically segment IVUS images in a user-friendly environment. Show less
IntroductionBicuspid aortic valve (BAV) patients have an increased risk to develop thoracic aortic complications. Little is known about the prevalence and severity of atherosclerosis in the BAV... Show moreIntroductionBicuspid aortic valve (BAV) patients have an increased risk to develop thoracic aortic complications. Little is known about the prevalence and severity of atherosclerosis in the BAV ascending aortic wall. This study evaluates and compares the prevalence of thoracic aortic atherosclerosis in BAV and tricuspid aortic valve (TAV) patients.MethodsAtherosclerosis was objectified using three diagnostic modalities in two separate BAV patient cohorts (with and without an aortic dilatation). Within the first group, atherosclerosis was graded histopathologically according to the modified AHA classification scheme proposed by Virmani et al. In the second group, the calcific load of the ascending aorta and coronary arteries, coronary angiographies and cardiovascular risk factors were studied. Patients were selected from a surgical database (treated between 2006-2020), resulting in a total of 128 inclusions.ResultsHistopathology showed atherosclerotic lesions to be more prevalent and severe in all TAV as compared to all BAV patients (OR 1.49 (95%CI 1.14 - 1.94); p = 0.003). Computed tomography showed no significant differences in ascending aortic wall calcification between all BAV and all TAV patients, although a tendency of lower calcific load in favor of BAV was seen. Coronary calcification was higher in all TAV as compared to all BAV (OR 1.30 (95%CI 1.06 - 1.61); p = 0.014).ConclusionAscending aortic atherosclerotic plaques were histologically more pronounced in TAV as compared to the BAV patients, while CT scans revealed equal amounts of calcific depositions within the ascending aortic wall. This study confirms less atherosclerosis in the ascending aortic wall and coronary arteries of BAV patients as compared to TAV patients. These results were not affected by the presence of a thoracic aortic aneurysm. Show less
Cardiovascular diseases are the leading cause of death worldwide, with atherosclerosis as most common underlying pathology. Atherosclerosis is characterized by arterial narrowing due to cholesterol... Show moreCardiovascular diseases are the leading cause of death worldwide, with atherosclerosis as most common underlying pathology. Atherosclerosis is characterized by arterial narrowing due to cholesterol and lipid accumulation. Despite available effective cholesterol lowering medication, considerable risk for recurrent vascular events remains. This residual risk is at least in part explained by high blood lipid levels. The research described in this thesis revealed novel therapeutic strategies that improve lipid metabolism and reduce atherosclerosis development in mice. Inhibition of the endocannabinoid system was found to be an effective strategy, as well as concomitant activation of two incretin hormone receptors, namely those for GIP and GLP1. For combined GIP/GLP1 receptor agonism we additionally showed strongly attenuated hepatic steatosis. We were also able to identify additional targets to attenuate hyperlipidemia by studying the mechanisms underlying the strong day-night rhythm of brown adipose tissue, which is a lipid combusting tissue. In this thesis, I also stress the importance of the choice in animal model when studying lipid-modifying interventions, and describe the development of the software tool RandoMice which can be used to improve the quality of preclinical studies by creating well-balanced experimental groups. Show less
Coronary computed tomography angiography allows detailed evaluation of the coronary atherosclerotic plaque, even before any cardiac symptoms are present. This thesis describes the important... Show moreCoronary computed tomography angiography allows detailed evaluation of the coronary atherosclerotic plaque, even before any cardiac symptoms are present. This thesis describes the important prognostic role that the burden, morphology, composition, and location of coronary plaque has, which allows to intervene at an early stage. Detection of subclinical coronary atherosclerosis allows early treatment and reduction of cardiovascular mortality and morbidity. Show less
Kuneman, J.H.; Hoogen, I.J. van den; Schultz, J.; Maaniitty, T.; Rosendael, A.R. van; Kamperidis, V.; ... ; Knuuti, J. 2023
Background: The various plaque components have been associated with ischemia and outcomes in patients with coronary artery disease (CAD). The main goal of this analysis was to test the hypothesis... Show moreBackground: The various plaque components have been associated with ischemia and outcomes in patients with coronary artery disease (CAD). The main goal of this analysis was to test the hypothesis that, at patient level, the fraction of non-calcified plaque volume (PV) of total PV is associated with ischemia and outcomes in patients with CAD. This ratio could be a simple and clinically useful parameter, if predicting outcomes. Methods: Consecutive patients with suspected CAD undergoing coronary computed tomography angiography with selective positron emission tomography perfusion imaging were selected. Plaque components were quantitatively analyzed at patient level. The fraction of various plaque components were expressed as percentage of total PV and examined among patients with non-obstructive CAD, suspected stenosis with normal perfusion, and those with reduced myocardial perfusion. Clinical outcomes included all-cause mortality and myocardial infarction. Results: In total, 494 patients (age 63 & PLUSMN; 9 years, 55% male) were included. Total PV and all plaque components were significantly larger in patients with reduced myocardial perfusion compared to patients with normal perfusion and those with non-obstructive CAD. During follow-up 35 events occurred. Patients with any plaque component & GE; median showed worse outcomes (log-rank p < 0.001 for all). In addition, low-attenuation plaque & GE; median was associated with worse outcomes independent of total PV (adjusted HR: 2.754, 95% CI: 1.022-7.0419, p = 0.045). The fractions of the various plaque components were not associated with outcomes. Conclusion: Larger total PV or any plaque component at patient level are associated with abnormal myocardial perfusion and adverse events. The various plaque components as fraction of total PV lack additional prognostic value. Show less
Cardiometabolic health is tightly controlled by a complex network of organ communication. Dysfunction of these lines of communication is associated with the development of cardiometabolic diseases... Show moreCardiometabolic health is tightly controlled by a complex network of organ communication. Dysfunction of these lines of communication is associated with the development of cardiometabolic diseases, indicating inter-organ cross-talk as a therapeutic target. Herein, I explored the therapeutic potential of targeting inter-organ communication in cardiometabolic diseases, including obesity, atherosclerotic cardiovascular disease and non-alcoholic steatohepatitis, based on which I proposed novel therapies to tackle these diseases. On one hand, strategies can focus on regulating the gut microbiota-centered inter-organ cross-talk. We demonstrated that dietary interventions are efficient to modulate the gut microbiota composition and function, thereby regulating the gut microbial metabolite production. In particularly, we showed that dietary supplementation of butyrate, a gut microbial metabolite, and choline, a nutrient enriched in red meat, can beneficially modulate the gut microbiota to alleviate adiposity. On the other hand, therapies can also focus on liver-centered inter-organ cross-talk. We showed that improving hepatocyte mitochondrial function by γ hydroxybutyric acid not only improves liver metabolic function, but also reverses obesity and its associated metabolic diseases. Besides, cardiometabolic health can be improved by regulating systemic levels of hepatokines (e.g. FGF21). We showed that FGF21-based pharmacotherapies can regulate the cross-talk between the liver and adipose tissue to improve cardiometabolic diseases, especially fibrotic non-alcoholic steatohepatitis and atherosclerotic cardiovascular disease. Thus, the findings described in this thesis emphasize the importance of inter-organ cross-talk for cardiometabolic diseases, and have improved our knowledge on the mechanisms that underlie the risk in the ever-increasing population of individuals who suffer from cardiometabolic diseases. Show less
Cardiovascular diseases are still a major concern for the global health. The main underlying pathology of this disease is atherosclerosis which is characterized by the accumulation of lipids and... Show moreCardiovascular diseases are still a major concern for the global health. The main underlying pathology of this disease is atherosclerosis which is characterized by the accumulation of lipids and immune cells in the arterial wall leading to a chronic local inflammation and lesion formation. In this thesis, we aimed to (1) validate the use of zebrafish in cholesterol metabolism and atherosclerosis research, (2) study the role of certain classes of scavenger receptors in lipoprotein uptake and cholesterol-based functions, and (3) validated two immune-based potential targets for atherosclerosis. Show less
Atherosclerosis is characterized by the accumulation of lipids and immune cells, including mast cells and B cells, in the arterial wall. Mast cells contribute to atherosclerotic plaque growth and... Show moreAtherosclerosis is characterized by the accumulation of lipids and immune cells, including mast cells and B cells, in the arterial wall. Mast cells contribute to atherosclerotic plaque growth and destabilization upon active degranulation. The FcεRI-IgE pathway is the most prominent mast cell activation route. Bruton's Tyrosine Kinase (BTK) is involved in FcεRI-signaling and may be a potential therapeutic target to limit mast cell activation in atherosclerosis. Additionally, BTK is crucial in B cell development and B-cell receptor signaling. In this project, we aimed to assess the effects of BTK inhibition on mast cell activation and B cell development in atherosclerosis. In human carotid artery plaques, we showed that BTK is primarily expressed on mast cells, B cells and myeloid cells. In vitro, BTK inhibitor Acalabrutinib dose-dependently inhibited IgE mediated activation of mouse bone marrow derived mast cells. In vivo, male Ldlr-/- mice were fed a high-fat diet for eight weeks, during which mice were treated with Acalabrutinib or control solvent. In Acalabrutinib treated mice, B cell maturation was reduced compared to control mice, showing a shift from follicular II towards follicular I B cells. Mast cell numbers and activation status were not affected. Acalabrutinib treatment did not affect atherosclerotic plaque size or morphology. In advanced atherosclerosis, where mice were first fed a high-fat diet for eight weeks before receiving treatment, similar effects were observed. Conclusively, BTK inhibition by Acalabrutinib alone did neither affect either mast cell activation nor early- and advanced atherosclerosis, despite the effects on follicular B cell maturation. Show less
Eenige, R. van; Ying, Z.X.; Tramper, N.; Wiebing, V.; Siraj, Z.; Boer, J.F. de; ... ; Kooijman, S. 2023
Background and aims: Combined agonism of the glucose-dependent insulinotropic polypeptide receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP1R) is superior to single GLP1R agonism in... Show moreBackground and aims: Combined agonism of the glucose-dependent insulinotropic polypeptide receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP1R) is superior to single GLP1R agonism in terms of glycemic control and lowering body weight in individuals with obesity and with or without type 2 diabetes mellitus. As both GIPR and GLP1R signaling have also been implicated in improving inflammatory responses and lipid handling, two crucial players in atherosclerosis development, here we aimed to investigate the effects of combined GIPR/GLP1R agonism in APOE*3-Leiden.CETP mice, a well-established mouse model for human-like lipoprotein metabolism and atherosclerosis development. Methods: Female APOE*3-Leiden.CETP mice were fed a Western-type diet (containing 16% fat and 0.15% cholesterol) to induce dyslipidemia, and received subcutaneous injections with either vehicle, a GIPR agonist (GIPFA-085), a GLP1R agonist (GLP-140) or both agonists. In the aortic root area, atherosclerosis development was assessed. Results: Combined GIPR/GLP1R agonism attenuated the development of severe atherosclerotic lesions, while single treatments only showed non-significant improvements. Mechanistically, combined GIPR/GLP1R agonism decreased markers of systemic low-grade inflammation. In addition, combined GIPR/GLP1R agonism markedly lowered plasma triglyceride (TG) levels as explained by reduced hepatic very-low-density lipoprotein (VLDL)-TG production as well as increased TG-derived fatty acid uptake by brown and white adipose tissue which was coupled to enhanced hepatic uptake of core VLDL remnants. Conclusions: Combined GIPR/GLP1R agonism attenuates atherosclerosis severity by diminishing inflammation and increasing VLDL turnover. We anticipate that combined GIPR/GLP1R agonism is a promising strategy to lower cardiometabolic risk in humans. Show less
In this thesis, we have addressed two key objectives: 1) to gain more insight in various pathophysiological aspects of cardiometabolic diseases including in the disease proneSouth Asian population,... Show moreIn this thesis, we have addressed two key objectives: 1) to gain more insight in various pathophysiological aspects of cardiometabolic diseases including in the disease proneSouth Asian population, and 2) to study the physiological effects of cold exposure and identify a novel pharmacological approach to directly target BAT. Show less
ImportanceAlthough atherosclerosis represents the primary driver of coronary artery disease, evaluation and treatment approaches have historically relied upon indirect markers of atherosclerosis th... Show moreImportanceAlthough atherosclerosis represents the primary driver of coronary artery disease, evaluation and treatment approaches have historically relied upon indirect markers of atherosclerosis that include surrogates (cholesterol), signs (angina), and sequelae (ischemia) of atherosclerosis. Direct quantification and characterization of atherosclerosis may encourage a precision heart care paradigm that improves diagnosis, risk stratification, therapeutic decision-making, and longitudinal disease tracking in a personalized fashion.ObservationsThe American College of Cardiology Innovations in Prevention Working Group introduce the Atherosclerosis Treatment Algorithms that personalize medical interventions based upon atherosclerosis findings from coronary computed tomography angiography (CTA) and cardiovascular risk factors. Through integration of coronary CTA-based atherosclerosis evaluation, clinical practice guidelines, and contemporary randomized controlled trial evidence, the Atherosclerosis Treatment Algorithms leverage patient-specific atherosclerosis burden and progression as primary targets for therapeutic intervention. After defining stages of atherosclerosis severity by coronary CTA, Atherosclerosis Treatment Algorithms are described for worsening stages of atherosclerosis for patients with lipid disorders, diabetes, hypertension, obesity, and tobacco use. The authors anticipate a rapid pace of research in the field, and conclude by providing perspectives on future needs that may improve efforts to optimize precision prevention of coronary artery disease. Importantly, the Atherosclerosis Treatment Algorithms are not endorsed by the American College of Cardiology, and should not be interpreted as a statement of American College of Cardiology policy.Conclusions and RelevanceWe describe a precision heart care approach that emphasizes atherosclerosis as the primary disease target for evaluation and treatment. To our knowledge, this is the first proposal to use coronary atherosclerosis burden and progression to personalize therapy selection and therapy changes, respectively. Show less
