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
Currently immunomodulatory compounds are under investigation for use in patients with cardiovascular disease, caused by atherosclerosis. These trials, using recurrent cardiovascular events as... Show moreCurrently immunomodulatory compounds are under investigation for use in patients with cardiovascular disease, caused by atherosclerosis. These trials, using recurrent cardiovascular events as endpoint, require enrollment of large patient groups. We investigated the effect of key risk factors for atherosclerosis development, ageing and smoking, on the immune system, with the objective to identify biomarkers differentiating between human populations, and potentially serving as endpoints for future phase 1B trials with immunomodulatory compounds. Blood was collected from young healthy volunteers (aged 18-25 years, n=30), young smokers (18-25 years, n=20), elderly healthy volunteers (>60 years, n=20), heavy smokers (>45 years, 15 packyears, n=11) and patients with stable coronary artery disease (CAD) (>60 years, n=27). Circulating immune cell subsets were characterized by flow cytometry, and collected plasma was evaluated by proteomics (Olink). Clear ageing effects were observed, mostly illustrated by a lower level in CD8+ and naïve CD4+ and CD8+ T cells, with an increase in CD4+ and CD8+ effector memory T cells in elderly healthy volunteers compared to young healthy volunteers. Heavy smokers showed a more inflammatory cellular phenotype, especially a shift in Th1/Th2 ratio: higher Th1 and lower Th2 percentages compared to young healthy volunteers. A significant decrease in circulating atheroprotective oxLDL-specific IgM was found in patients with CAD compared to young healthy volunteers. Elevated pro-inflammatory and chemotactic proteins TREM1 and CCL11 were observed in elderly volunteers compared to young volunteers. In addition, heavy smokers had an increase in pro-inflammatory cytokine IL-6 and lysosomal protein LAMP3. These data show that ageing and smoking are associated with an inflammatory immunophenotype, and that heavy smokers or aged individuals may serve as potential populations for future clinical trials investigating immunomodulatory drugs targeted for cardiovascular disease. Show less
Cardiovascular diseases are the primary cause of death in the world with atherosclerosis as primary underlying cause. Atherosclerosis is characterized by cholesterol accumulation in the vessel wall... Show moreCardiovascular diseases are the primary cause of death in the world with atherosclerosis as primary underlying cause. Atherosclerosis is characterized by cholesterol accumulation in the vessel wall and inflammation of the vessel wall of medium to large size arteries. Both cholesterol accumulation and inflammation are pathogenic in the context of atherosclerosis. Current treatment regimens are tailored to reduce cholesterol levels in the blood. However, even a successful lowering of cholesterol is in many patients not sufficient to prevent a major cardiovascular event due to unresolved inflammation. Therefore, the immune system provides an interesting therapeutic target for the treatment of atherosclerosis. In this thesis we have explored the effect on atherosclerosis of several immunomodulatory strategies in pre-clinical models.As cholesterol is not soluble in water, cholesterol is transported in the bloodstream in particles called lipoproteins. The low-density lipoprotein (LDL) carries the highest concentration of cholesterol and accumulates in the vessel wall where a pathogenic specific immune response against LDL is instigated. In this thesis we have used several strategies to modulate the specific immune response against LDL, inducing LDL-specific regulatory T cells, antibodies, and cytotoxic T cells. Through immunoproteasomal inhibition we assessed the effect of general immune inhibition on atherosclerosis. Show less
