In addition, the AS group displayed the highest protein levels of TXNIP, NLRP3, ASC, caspase-1, IL-1β, and IL-18, while the levels of these proteins in the AS + H <sub>2</sub> S group were higher than those in the sham group.
Activation of macrophage inflammasomes leads to interleukin (IL)-1β and IL-18 secretion and promotes atherosclerosis and its complications in mice and humans.
Moreover, the use of loss- or gain-of-function genetically modified, atherosclerosis-prone mice has provided strong experimental evidence for a causal role of innate and adaptive immunity in atherosclerosis and has revealed the pathogenic activity of proinflammatory cytokines, including TNF (tumor necrosis factor)-α, IL (interleukin)-1β, IL-6, and IL-18, and the atheroprotective effect of anti-inflammatory cytokines, including IL-10 and TGF-β.
The level of IL-17 and IL-18 in the atherosclerosis and disease control groups was higher than that in the healthy control group, and the level of IL-17 and IL-18 in the atherosclerosis was higher than that in the disease control group.
Therefore, in order to investigate IL-18 contribution to the immuno-inflammatory processes underlying atherosclerosis, a systems approach has been used in our studies.
It is now also known that cholesterol crystals are present through all stages of atherosclerosis and can activate the NLRP3 inflammasome within these inflammatory cells to produce interleukin 1β and interleukin 18 - key mediators in the inflammatory cascade that drive plaque progression and instability.
Pyroptosis is characterized by rapid plasma membrane rupture, with the consequent release of intracellular contents and pro-inflammatory mediators, including interleukin (IL)-1β, IL-18, and the alarmin HMGB-1.Recent studies have shown that pyroptosis may be involved in atherosclerosis and play an important role in atherosclerotic lesion instability.
Increased plasma levels of IL-1β and IL-18, aggravated macrophage infiltration into atherosclerotic lesions, and accelerated development of atherosclerosis were detected in HHcy mice as compared with control mice, and were associated with the activation of NLRP3 inflammasomes.
In this article, we aimed to present an updated review on these aspects regarding the contribution of IL-18 to important diseases such as cancer, autoimmunity, and inflammatory-mediated conditions including allergic diseases, metabolic syndrome, and atherosclerosis.
We report that common variation in the interleukin 18 gene is related to acute myocardial infarction, a frequent clinical manifestation of atherosclerosis and thrombosis in coronary arteries.
Together with recent reports, showing IL-18 to be predictive for cardiovascular events, our findings could provide the basis for further research of the role of IL-18 as a link and possible target in the association between MetS and atherosclerosis.
Furthermore, we demonstrated the expression of IL-18BP in atherosclerotic lesions in a rhesus model of atherosclerosis, underscoring the need to fully understand the role of this protein as a primary negative regulator of IL-18 in multiple disease processes.
Moreover, when mice deficient in low-density lipoprotein receptor (LDLR) were bone-marrow transplanted with NLRP3-deficient, ASC (also known as PYCARD)-deficient or IL-1alpha/beta-deficient bone marrow and fed on a high-cholesterol diet, they had markedly decreased early atherosclerosis and inflammasome-dependent IL-18 levels.
To conclude, IL-18 promoter -137G/C polymorphism influences IL-18 levels and the occurrence of coronary artery disease, suggesting that IL-18 is causally involved in the development of atherosclerosis.
Collectively, our results demonstrate that the coexpression and regulation of IL-18 and EMMPRIN in the vessel wall may amplify the inflammatory cascade and promote atherosclerosis and remodeling.