In this thesis, the role of mast cells in atherosclerosis and novel therapeutic strategies to inhibit atherosclerosis progression are discussed. The first part of the thesis specifically focuses on... Show moreIn this thesis, the role of mast cells in atherosclerosis and novel therapeutic strategies to inhibit atherosclerosis progression are discussed. The first part of the thesis specifically focuses on the relation between mast cells and advanced human atherosclerotic plaque characteristics. The second part of the thesis focuses on identifying and examining new potential therapeutic targets to treat atherosclerosis. In chapter 2, we implemented a flow-cytometry-based method to identify mast cells and its activation status in advanced human plaques. We evaluated the relation between mast cells and key features of human plaque stability. In chapter 3, we further investigated the link between mast cells and plaque stability in a large patient cohort from the BiKe biobank. In particular, we examined the role of mast cells in plaque calcification via vascular smooth muscle cells. In the second part of the thesis, we used single-cell RNA sequencing data of human plaques to identify novel therapeutic targets in atherosclerosis. In chapter 4, we examined the therapeutic potential of Bruton’s Tyrosine Kinase in atherosclerosis by treating Ldlr-/- mice with a small molecule inhibitor in early and advanced experimental atherosclerosis. Chapter 5 explores Leukemia Inhibitory Factor Receptor signaling as novel target in the treatment of atherosclerosis. Show less
Atherosclerosis is the most prominent underlying pathology of cardiovascular disease and an important cause of major adverse cardiovascular events. Chronic inflammation drives growth and... Show moreAtherosclerosis is the most prominent underlying pathology of cardiovascular disease and an important cause of major adverse cardiovascular events. Chronic inflammation drives growth and destabilization of atherosclerotic plaques. Recent single-cell technologies demonstrated that T-cells, including CD4+ and CD8+ T-cells, form a major immune population within human and mouse atherosclerotic lesions. These T-cells show signs of recent TCR activation, and clonal expansion, suggesting an autoimmune component in the progression of atherosclerosis. Although CD4+ T-cells have been widely studied in the context of atherosclerosis, understanding the implications of CD8+ T-cells in disease progression has proven to be more challenging, due to inconsistent findings. This thesis focuses on elucidating the effects of different CD8+ T-cell subsets, and their potential targets, within the atherosclerotic lesion. Show less
Cardiovascular diseases, the leading cause of death worldwide, are often the result of atherosclerosis, a chronic inflammatory disease where lipids and immune cells accumulate in blood vessel walls... Show moreCardiovascular diseases, the leading cause of death worldwide, are often the result of atherosclerosis, a chronic inflammatory disease where lipids and immune cells accumulate in blood vessel walls. While LDL cholesterol has long been in the spotlight, recent research highlights triglycerides as another key factor contributing to cardiovascular risk. This thesis demonstrates how lipids alter processes that regulate immune cell function, potentially influencing atherosclerosis development. Using human population studies, we identified changes in genes linked to lipid metabolism and the immune system. We then employed Mendelian randomization, a statistical approach, to assess cause and consequence. Additionally, cell culture experiments provided a controlled environment to study the effect of lipids on specific immune cells. Notably, we discovered that triglycerides, besides their role in cardiovascular diseases, can suppress allergic reactions. These findings shed light on the complex interplay between lipids and the immune system, offering avenues for further research using advanced technologies. We identified 374 genes involved in these processes, many previously unreported in similar studies. Of these, 88 are targets of approved drugs. This knowledge supports the development of new treatments to prevent and manage cardiovascular diseases, marking a significant step in addressing a global health challenge. Show less
Background: The Plaque At RISK (PARISK) study demonstrated that patients with a carotid plaque with intraplaque hemorrhage (IPH) have an increased risk of recurrent ipsilateral ischemic... Show moreBackground: The Plaque At RISK (PARISK) study demonstrated that patients with a carotid plaque with intraplaque hemorrhage (IPH) have an increased risk of recurrent ipsilateral ischemic cerebrovascular events. It was previously reported that symptomatic carotid plaques with IPH showed higher IPH signal intensity ratios (SIR) and larger IPH volumes than asymptomatic plaques. We explored whether IPH SIR and IPH volume are associated with future ipsilateral ischemic cerebrovascular events beyond the presence of IPH. Methods: Transient ischemic attack and ischemic stroke patients with mild-to-moderate carotid stenosis and an ipsilateral IPH-positive carotid plaque (n = 89) from the PARISK study were included. The clinical endpoint was a new ipsilateral ischemic cerebrovascular event during 5 years of follow-up, while the imaging-based endpoint was a new ipsilateral brain infarct on brain magnetic resonance imaging (MRI) after 2 years (n = 69). Trained observers delineated IPH, a hyperintense region compared to surrounding muscle tissue on hyper T1-weighted magnetic resonance images. The IPH SIR was the maximal signal intensity in the IPH region divided by the mean signal intensity of adjacent muscle tissue. The associations between IPH SIR or volume and the clinical and imaging-based endpoint were investigated using Cox proportional hazard models and logistic regression, respectively. Results: During 5.1 (interquartile range: 3.1–5.6) years of follow-up, 21 ipsilateral cerebrovascular ischemic events were identified. Twelve new ipsilateral brain infarcts were identified on the 2-year neuro MRI. There was no association for IPH SIR or IPH volume with the clinical endpoint (hazard ratio (HR): 0.89 [95% confidence interval: 0.67–1.10] and HR: 0.91 [0.69–1.19] per 100-µL increase, respectively) nor with the imaging-based endpoint (odds ratio (OR): 1.04 [0.75–1.45] and OR: 1.21 [0.87–1.68] per 100-µL increase, respectively). Conclusion: IPH SIR and IPH volume were not associated with future ipsilateral ischemic cerebrovascular events. Therefore, quantitative assessment of IPH of SIR and volume does not seem to provide additional value beyond the presence of IPH for stroke risk assessment. Show less
This thesis investigated novel parameters on coronary computed tomography angiography for the characterization of coronary artery disease (CAD) and explored left ventricular (reverse) remodeling in... Show moreThis thesis investigated novel parameters on coronary computed tomography angiography for the characterization of coronary artery disease (CAD) and explored left ventricular (reverse) remodeling in patients with severe aortic stenosis (AS). Precursors of culprit lesions of patients who developed an acute coronary syndrome had a higher pericoronary adipose tissue attenuation as compared to non-culprit lesions in these patients and compared to lesions of patients with stable CAD. In addition, we observed that overall plaque burden was associated with increased risk of adverse events in patients with stable CAD. The relative fractions of the various plaque components of total plaque volume lacked additional prognostic value. Furthermore, patient with diabetes mellitus had a lower coronary volume to left ventricular mass ratio. Next, sex differences in left ventricular (LV) remodeling in patients with severe AS who underwent transcatheter aortic valve implantation (TAVI) were evaluated. No sex differences in LV (reverse) remodeling were observed and this was not associated with sex differences in outcome after TAVI. Moreover, LV reverse remodeling after TAVI was not impaired by subclinical leaflet thrombosis. LV ejection fraction (LVEF) improved significantly after TAVI, and patients with reduced baseline LVEF revealed the greatest improvement in LVEF. Show less
Svecla, M.; Moregola, A.; Dalt, L. da; Nour, J.; Baragetti, A.; Uboldi, P.; ... ; Norata, G.D. 2024
The asialoglycoprotein receptor 1 (ASGR1), a multivalent carbohydrate-binding receptor that primarily is responsible for recognizing and eliminating circulating glycoproteins with exposed... Show moreThe asialoglycoprotein receptor 1 (ASGR1), a multivalent carbohydrate-binding receptor that primarily is responsible for recognizing and eliminating circulating glycoproteins with exposed galactose (Gal) or N-acetylgalactosamine (GalNAc) as terminal glycan residues, has been implicated in modulating the lipid metabolism and reducing cardiovascular disease burden. In this study, we investigated the impact of ASGR1 deficiency (ASGR1−/−) on atherosclerosis by evaluating its effects on plaque formation, lipid metabolism, circulating immunoinflammatory response, and circulating N-glycome under the hypercholesterolemic condition in ApoE-deficient mice. After 16 weeks of a western-type diet, ApoE−/−/ASGR1−/− mice presented lower plasma cholesterol and triglyceride levels compared to ApoE−/−. This was associated with reduced atherosclerotic plaque area and necrotic core formation. Interestingly, ApoE−/−/ASGR1−/− mice showed increased levels of circulating immune cells, increased AST/ALT ratio, and no changes in the N-glycome profile and liver morphology. The liver of ApoE−/−/ASGR1−/− mice, however, presented alterations in the metabolism of lipids, xenobiotics, and bile secretion, indicating broader alterations in liver homeostasis beyond lipids. These data suggest that improvements in circulating lipid metabolism and atherosclerosis in ASGR1 deficiency is paralleled by a deterioration of liver injury. These findings point to the need for additional evaluation before considering ASGR1 as a pharmacological target for dyslipidemia and cardiovascular disorders. Show less
Cytokines are involved in all stages of atherosclerosis, generally contributing to disease progression. Previously, members of the Interleukin (IL)-6 cytokine family, such as IL-6, oncostatin M,... Show moreCytokines are involved in all stages of atherosclerosis, generally contributing to disease progression. Previously, members of the Interleukin (IL)-6 cytokine family, such as IL-6, oncostatin M, and cardiotrophin-1, have been extensively studied in atherosclerosis. However, the role of leukemia inhibitory factor (LIF), member of the IL-6 family, and its receptor (LIFR), remains to be further elucidated. Therefore, the aim of this study is to provide insight in LIF receptor signalling in atherosclerosis development. Single-cell RNA sequencing analysis of human carotid artery plaques revealed that mast cells highly express LIF, whereas LIFR was specifically expressed on activated endothelial cells. A similar expression pattern of Lifr was observed in mouse atherosclerotic plaques. Next, female Western-type diet fed Ldlr-/- mice were treated with LIF receptor inhibitor EC359 (5 mg/kg s.c., n = 15) or control solvent (n = 15) three times per week for eight weeks. Stenosis grade was reduced in the aortic root of EC359 treated mice compared to control mice, but treatment did not affect plaque composition. Serum cholesterol levels were significantly reduced in EC359 treated mice, likely attributed to a reduction in VLDL cholesterol levels. Furthermore, LIF receptor inhibition reduced Pecam1 and Vcam1 expression in the aorta. Consequently, immune cell infiltration was reduced in aortic plaques of EC359 treated mice compared to control mice. Conclusively, we demonstrated that LIF receptor is a potential therapeutic target in atherosclerosis by reducing plaque size, attributed to lower serum cholesterol levels, reduced endothelial activation and less immune cell infiltration in the plaque. Show less
Atherosclerosis, a leading cause of cardiovascular disease, is characterized by lipid accumulation in blood vessel walls. This chronic inflammation leads to plaque formation, increasing the risk of... Show moreAtherosclerosis, a leading cause of cardiovascular disease, is characterized by lipid accumulation in blood vessel walls. This chronic inflammation leads to plaque formation, increasing the risk of heart attacks and strokes. While traditionally linked to cholesterol and macrophages, emerging research highlights the roles of triglycerides and T cells in atherosclerosis development. Triglycerides can exacerbate the disease, while T cells are among the most abundant immune cells in atherosclerotic plaques.This thesis investigates how triglycerides and fatty acids influence T cell function, employing in vitro, -omics, and in vivo methods. It maps the effects of various fatty acids on T cell metabolism, activation, and differentiation. Notably, in vitro exposure to oleic acid resulted in a pro-inflammatory transcriptomic profile in CD4+ T cells, enhancing the likelihood of differentiation into IL-9 producing cells, linked to atherosclerosis pathogenesis. In contrast, eicosapentaenoic acid showed strong anti-inflammatory transcriptomics. Finally, a natural in vivo experiment revealed a pro-inflammatory transcriptomic profile in T cells from individuals with elevated triglyceride levels as compared to those without. This work opens new avenues for further research and enhances our understanding of the intricate relationship between fatty acids, triglycerides and T cells, which effects on how we understand human health and disease. Show less
Healthy aging is one of the prime goals in today's society and atherosclerosis is among the greatest causes of morbidity in elderly. Cardiovascular disease patients receiving treatment are often of... Show moreHealthy aging is one of the prime goals in today's society and atherosclerosis is among the greatest causes of morbidity in elderly. Cardiovascular disease patients receiving treatment are often of advanced aged and have an aged immune system, which limits translating experimental findings to the patient. It is therefore essential to take aging into consideration when investigating immune cells and their responses in atherosclerosis studies. This thesis describes research exploring the impact of aging on the immunological landscape in atherosclerotic cardiovascular disease using single-cell profiling. Through the use of a highly translational aging mouse model of atherosclerosis, we characterized inflammation in the plaques of young versus old mice. We discovered new cell types (T and B cells) not present in young mice with atherosclerosis. These cells secrete a variety of inflammatory factors that may contribute to the disease process and exacerbate arteriosclerosis. While the aged B cell is more prevalent in female mice, the aged T cell is more abundant in male mice. We then also found these aged cells in the blood and plaques of cardiovascular disease patients. These aged cell types could be interesting targets for future treatments against progression of atherosclerotic cardiovascular disease. Show less
Nanoparticles can be used as delivery systems for both small molecules and macromolecules such as proteins, peptides or oligonucleotides. This thesis focuses on the use of liposomes, nanometric... Show moreNanoparticles can be used as delivery systems for both small molecules and macromolecules such as proteins, peptides or oligonucleotides. This thesis focuses on the use of liposomes, nanometric vesicles formed by a lipid bilayer enclosing an aqueous core. Liposomes are highly versatile delivery systems. Fine tuning their physicochemical properties such as size, shape, rigidity or surface charge allows the control of the liposome's biological effect. Among the different applications for liposomes, antigen delivery is especially interesting. Liposomes can protect antigens from degradation, and they can direct the antigen delivery to specialised cells such as antigen-presenting cells (APCs), key for the induction of immune responses. APCs will present antigens to T cells to generate an immune response. The way in which these cells present the antigen will determine the type of immune response generated, either a pro-inflammatory response necessary to fight viral and bacterial infections or a tolerogenic response useful to temper down inflammation, for example in the context of cardiovascular diseases like atherosclerosis. Therefore, these formulations can be used as vaccines against inflammatory diseases and as prophylactic vaccines against infectious diseases. In this thesis, we examine key aspects of liposome formulations including the elucidation of target antigens to be used in a tolerogenic vaccine against atherosclerosis, the manufacture of these formulations using microfluidics, the use of vitaminD3 as a tolerogenic adjuvant and the role of liposome rigidity in the tolerogenic effect of these nanoparticles. Furthermore, we explore the use of liposomes to induce protective anti-viral immunity against influenza. Show less
Zhang, F.; Yao, H.; Langzam, E.; Meng, Q.L.; Meng, X.; Geest, R.J. van der; ... ; Yang, L. 2024
Background Computed tomography (CT) is the usual modality for diagnosing stroke, but conventional CT angiography reconstructions have limitations. Methods A phantom with tubes of known diameters... Show moreBackground Computed tomography (CT) is the usual modality for diagnosing stroke, but conventional CT angiography reconstructions have limitations. Methods A phantom with tubes of known diameters and wall thickness was scanned for wall detectability, wall thickness, and contrast-to-noise ratio (CNR) on conventional and spectral black-blood (SBB) images. The clinical study included 34 stroke patients. Diagnostic certainty and conspicuity of normal/abnormal intracranial vessels using SBB were compared to conventional. Sensitivity/specifcity/accuracy of SBB and conventional were compared for plaque detectability. CNR of the wall/lumen and quantitative comparison of remodeling index, plaque burden, and eccentricity were obtained for SBB imaging and high-resolution magnetic resonance imaging (hrMRI). Results The phantom study showed improved detectability of tube walls using SBB (108/108, 100% versus conventional 81/108, 75%, p<0.001). CNRs were 75.9±62.6 (mean±standard deviation) for wall/lumen and 22.0±17.1 for wall/water using SBB and 26.4±15.3 and 101.6±62.5 using conventional. Clinical study demonstrated (i) improved certainty and conspicuity of the vessels using SBB versus conventional (certainty, median score 3 versus 0; conspicuity, median score 3 versus 1 (p<0.001)), (ii) improved sensitivity/specifcity/accuracy of plaque (≥1.0 mm) detectability (0.944/0.981/0.962 versus 0.239/0.743/0.495) (p<0.001), (iii) higher wall/lumen CNR of SBB of (78.3±50.4/79.3±96.7) versus hrMRI (18.9±8.4/24.1±14.1) (p<0.001), and (iv) excellent reproducibility of remodeling index, plaque burden, and eccentricity using SBB versus hrMRI (intraclass correlation coefcient 0.85–0.94). Conclusions SBB can enhance the detectability of intracranial plaques with an accuracy similar to that of hrMRI. Relevance statement This new spectral black-blood technique for the detection and characterization of intracranial vessel atherosclerotic disease could be a time-saving and cost-efective diagnostic step for clinical stroke patients. It may also facilitate prevention strategies for atherosclerosis. Show less
A strong correlation exists between abdominal aortopathy and atherosclerosis. In thoracic aortopathy however, the prevalence of atherosclerosis and its role in the etiology of thoracic aortopathy... Show moreA strong correlation exists between abdominal aortopathy and atherosclerosis. In thoracic aortopathy however, the prevalence of atherosclerosis and its role in the etiology of thoracic aortopathy remained unknown. This thesis therefore studied the cardiovascular disease burden within this patient group. These results showed that the prevalence of atherosclerosis (i.e. cardiovascular disease burden), in contrast to abdominal aortopathy, is not increased within the thoracic aortopathy population. Show less
Smit, V.; Mol, J. de; Bernabé Kleijn, M.N.A.B.; Depuydt, M.A.C.; Winther, M.P.J. de, Bot, I.; Kuiper, J.; Foks, A.C. 2024
Atherosclerosis, the main underlying pathology of cardiovascular disease, is a chronic inflammatory disease characterized by lipid accumulation and immune cell responses in the vascular wall,... Show moreAtherosclerosis, the main underlying pathology of cardiovascular disease, is a chronic inflammatory disease characterized by lipid accumulation and immune cell responses in the vascular wall, resulting in plaque formation. It is well-known that atherosclerosis prevalence and manifestation vary by sex. However, sexual dimorphism in the immune landscape of atherosclerotic plaques has up to date not been studied at high-resolution. In this study, we investigated sex-specific differences in atherosclerosis development and the immunological landscape of aortas at single-cell level in aged Ldlr-/- mice.We compared plaque morphology between aged male and female chow diet-fed Ldlr-/- mice (22 months old) with histological analysis. Using single-cell RNA-sequencing and flow cytometry on CD45+ immune cells from aortas of aged Ldlr-/- mice, we explored the immune landscape in the atherosclerotic environment in males and females.We show that plaque volume is comparable in aged male and female mice, and that plaques in aged female mice contain more collagen and cholesterol crystals, but less necrotic core and macrophage content compared to males. We reveal increased immune cell infiltration in female aortas and found that expression of pro-atherogenic markers and inflammatory signaling pathways was enriched in plaque immune cells of female mice. Particularly, female aortas show enhanced activation of B cells (Egr1, Cd83, Cd180), including age-associated B cells, in addition to an increased M1/M2 macrophage ratio, where Il1b+ M1-like macrophages display a more pro-inflammatory phenotype (Nlrp3, Cxcl2, Mmp9) compared to males. In contrast, increased numbers of age-associated Gzmk+CD8+ T cells, dendritic cells, and Trem2+ macrophages were observed in male aortas.Altogether, our findings highlight that sex is a variable that contributes to immunological differences in the atherosclerotic plaque environment in mice and provide valuable insights for further preclinical studies into the impact of sex on the pathophysiology of atherosclerosis. Show less
Tissue resident memory T (TRM) cells are a T-cell subset that resides at the site of prior antigen recognition to protect the body against reoccurring encounters. Besides their protective function,... Show moreTissue resident memory T (TRM) cells are a T-cell subset that resides at the site of prior antigen recognition to protect the body against reoccurring encounters. Besides their protective function, TRM cells have also been implicated in inflammatory disorders. TRM cells are characterized by the expression of CD69 and transcription factors Hobit (homolog of Blimp-1 [B lymphocyte-induced maturation protein 1] in T cells) and Blimp-1. As the majority of T cells in the arterial intima expresses CD69, TRM cells may contribute to the pathogenesis of atherosclerosis as well. Here, we aimed to assess the presence and potential role of TRM cells in atherosclerosis.To identify TRM cells in human atherosclerotic lesions, a single-cell RNA-sequencing data set was interrogated, and T-cell phenotypes were compared with that of integrated predefined TRM cells. The presence and phenotype of TRM in atherosclerotic lesions was corroborated using a mouse model that enabled tracking of Hobit-expressing TRM cells. To explore the function of TRM cells during atherogenesis, RAG1-/- (RAG1 deficient) LDLr-/- (low-density lipoprotein receptor knockout) mice received a bone marrow transplant from HobitKO/CREBlimp-1flox/flox mice, which exhibit abrogated TRM cell formation, whereafter the mice were fed a Western-type diet for 10 weeks.Human atherosclerotic lesions contained T cells that exhibited a TRM cell-associated gene signature. Moreover, a fraction of these T cells clustered together with predefined TRM cells upon integration. The presence of Hobit-expressing TRM cells in the atherosclerotic lesion was confirmed in mice. These lesion-derived TRM cells were characterized by the expression of CD69 and CD49α. Moreover, we demonstrated that this small T-cell subset significantly affects lesion composition, by reducing the amount of intralesional macrophages and increasing collagen content.TRM cells, characterized by the expression of CD69 and CD49α, constitute a minor population in atherosclerotic lesions and are associated with increased lesion stability in a Hobit and Blimp-1 knockout mouse model. Show less
Acute cardiovascular syndromes, including myocardial infarction or stroke, are the principal cause of death in the Western society. The main underlying pathology of cardiovascular diseases is... Show moreAcute cardiovascular syndromes, including myocardial infarction or stroke, are the principal cause of death in the Western society. The main underlying pathology of cardiovascular diseases is atherosclerosis, which is caused by the accumulation of lipids and inflammatory cells in the vessel wall, in so-called atherosclerotic plaques. Current therapies mainly target the disturbed lipid homeostasis, but recent clinical trials have shown a clear benefit in treating patients with anti-inflammatory drugs. However, more specific targeting is required to avoid unwanted side effects. In this thesis, we have generated a detailed atlas of all the cells present in human atherosclerotic plaques using a novel state-of-the-art technique called single-cell RNA sequencing. This data set can be applied as a powerful tool to select potential drug targets with a functional relevance for atherosclerosis. We showed that the majority of the immune cells in the human atherosclerotic plaque consisted of T cells. Subsequently, we identified a pro-inflammatory population of T cells that likely responds to a plaque-derived antigen, suggesting that atherosclerosis has an autoimmune-like component. Finally, we have applied our single-cell atlas to define and validate targets to intervene with the recruitment and activation of mast cells and other immune cells in atherosclerosis. Show less
Viral infections have been associated with the progression of atherosclerosis and CD8+ T-cells directed against common viruses, such as influenza, Epstein-Barr virus, and cytomegalovirus, have been... Show moreViral infections have been associated with the progression of atherosclerosis and CD8+ T-cells directed against common viruses, such as influenza, Epstein-Barr virus, and cytomegalovirus, have been detected inside human atherosclerotic lesions. These virus-specific CD8+ T-cells have been hypothesized to contribute to the development of atherosclerosis; however, whether they affect disease progression directly remains unclear. In this study, we aimed to characterize the activation status of virus-specific CD8+ T-cells in the atherosclerotic lesion.\nThe presence, clonality, tissue enrichment, and phenotype of virus-associated CD8+ T-cells in atherosclerotic lesions were assessed by exploiting bulk T-cell receptor-β sequencing and single-cell T-cell receptor (α and β) sequencing datasets on human endarterectomy samples and patient-matched blood samples. To investigate if virus-specific CD8+ T-cells can be activated through T-cell receptor stimulation in the atherosclerotic lesion, the immunopeptidome of human plaques was determined.\nVirus-associated CD8+ T-cells accumulated more in the atherosclerotic lesion (mean=2.0%), compared with patient-matched blood samples (mean=1.4%; P=0.05), and were more clonally expanded and tissue enriched in the atherosclerotic lesion in comparison with nonassociated CD8+ T-cells from the lesion. Single-cell T-cell receptor sequencing and flow cytometry revealed that these virus-associated CD8+ T-cells were phenotypically highly similar to other CD8+ T-cells in the lesion and that both exhibited a more activated phenotype compared with circulating T-cells. Interestingly, virus-associated CD8+ T-cells are unlikely to be activated through antigen-specific interactions in the atherosclerotic lesion, as no virus-derived peptides were detected on HLA-I in the lesion.\nThis study suggests that virus-specific CD8+ T-cells are tissue enriched in atherosclerotic lesions; however, their potential contribution to inflammation may involve antigen-independent mechanisms. Show less
Elieh-Ali-Komi, D.; Bot, I.; Rodríguez-González, M.; Maurer, M. 2024
Mast cells (MCs) are commonly recognized for their crucial involvement in the pathogenesis of allergic diseases, but over time, it has come to light that they also play a role in the... Show moreMast cells (MCs) are commonly recognized for their crucial involvement in the pathogenesis of allergic diseases, but over time, it has come to light that they also play a role in the pathophysiology of non-allergic disorders including atherosclerosis. The involvement of MCs in the pathology of atherosclerosis is supported by their accumulation in atherosclerotic plaques upon their progression and the association of intraplaque MC numbers with acute cardiovascular events. MCs that accumulate within the atherosclerotic plaque release a cocktail of mediators through which they contribute to neovascularization, plaque progression, instability, erosion, rupture, and thrombosis. At a molecular level, MC-released proteases, especially cathepsin G, degrade low-density lipoproteins (LDL) and mediate LDL fusion and binding of LDL to proteoglycans (PGs). Through a complicated network of chemokines including CXCL1, MCs promote the recruitment of among others CXCR2+ neutrophils, therefore, aggravating the inflammation of the plaque environment. Additionally, MCs produce extracellular traps which worsen inflammation and contribute to atherothrombosis. Altogether, evidence suggests that MCs actively, via several underlying mechanisms, contribute to atherosclerotic plaque destabilization and acute cardiovascular syndromes, thus, making the study of interventions to modulate MC activation an interesting target for cardiovascular medicine. Show less
Wu, J.P.; Zou, Y.; Meng, X.; Fan, Z.Y.; Geest, R. van der; Cui, F.; ... ; Zhang, F. 2023
ObjectivesCarotid atherosclerosis plays an essential role in the occurrence of ischemic stroke. This study aimed to investigate whether a larger burden of napkin-ring sign (NRS) plaques on... Show moreObjectivesCarotid atherosclerosis plays an essential role in the occurrence of ischemic stroke. This study aimed to investigate whether a larger burden of napkin-ring sign (NRS) plaques on cervicocerebral computed tomography angiography (CTA) increased the risk of acute ischemic stroke (AIS).MethodsThis retrospective, single-center, cross-sectional study enrolled patients with NRS plaques identified in the subclavian arteries, brachiocephalic trunk, carotid arterial system, and vertebrobasilar circulation on contrast-enhanced cervicocerebral CTA. Patients were divided into AIS and non-AIS groups based on imaging within 12 h of symptom onset. Univariate and multivariate logistic regression analyses were performed to determine the risk factor of AIS occurrence.ResultsA total of 202 patients (66.72 years ± 8.97, 157 men) were evaluated. Plaques with NRS in each subject of the AIS group (N = 98) were significantly more prevalent than that in the control group (N = 104) (1.96 ± 1.17 vs 1.41 ± 0.62). In the AIS group, there were substantially more NRS plaques on the ipsilateral side than contralateral side (1.55 ± 0.90 vs. 0.41 ± 0.66). NRS located on the ipsilateral side of the AIS showed an area under the receiver curve (AUC) of 0.86 to identify ischemic stroke. NRS plaque amounts were an independent risk factor for AIS occurrence (odds ratio, 1.86) after adjusting for other factors.ConclusionsIncreased incidence of napkin-ring sign plaques on cervicocerebral CTA was positively associated with AIS occurrence, which could aid in detecting asymptomatic atherosclerotic patients at high risk of AIS in routine screening or emergency settings. Show less
Slijkhuis, N.; Towers, M.; Mirzaian, M.; Korteland, S.A.; Heijs, B.; Gaalen, K. van; ... ; Soest, G. van 2023
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
