Atherosclerosis and thrombosis

Author(s):  
Lina Badimon ◽  
Gemma Vilahur

Atherosclerosis is the main underlying cause of heart disease. The continuous exposure to cardiovascular risk factors induces endothelial activation/dysfunction which enhances the permeability of the endothelial layer and the expression of cytokines/chemokines and adhesion molecules. This results in the accumulation of lipids (low-density lipoprotein particles) in the intimal layer and the triggering of an inflammatory response. Accumulated low-density lipoprotein particles attached to the extracellular matrix suffer modifications and become pro-atherogenic, enhancing leucocyte recruitment and further transmigration across the endothelium into the intima. Infiltrated pro-atherogenic monocytes (mainly Mon2) differentiate into macrophages which acquire a specialized phenotypic polarization (protective/M1 or harmful/M2), depending on the stage of the atherosclerosis progression. Once differentiated, macrophages upregulate pattern recognition receptors capable of engulfing modified low-density lipoprotein, leading to foam cell formation. Foam cells release growth factors and cytokines that promote vascular smooth muscle cell migration into the intima, which then internalize low-density lipoproteins via low-density lipoprotein receptor-related protein-1 receptors becoming foam cells. As the plaque evolves, the number of vascular smooth muscle cells decline, whereas the presence of fragile/haemorrhagic neovessels and calcium deposits increases, promoting plaque destabilization. Disruption of this atherosclerotic lesion exposes thrombogenic surfaces rich in tissue factor that initiate platelet adhesion, activation, and aggregation, as well as thrombin generation. Platelets also participate in leucocyte and progenitor cell recruitment are likely to mediate atherosclerosis progression. Recent data attribute to extracellular vesicles (mainly microvesicles) a role in all stages of atherosclerosis development and evidence their potential use as systemic biomarkers of thrombus growth. This chapter reviews our current understanding of the pathophysiological mechanisms involved in atherogenesis, highlights platelet contribution to thrombosis and atherosclerosis progression, and provides new insights into how atherothrombosis may be prevented and modulated.

Author(s):  
Lina Badimon ◽  
Gemma Vilahur

Atherosclerosis is the main underlying cause of heart disease. The continuous exposure to cardiovascular risk factors induces endothelial activation/dysfunction which enhances the permeability of the endothelial layer and the expression of cytokines/chemokines and adhesion molecules. This results in the accumulation of lipids (low-density lipoprotein particles) in the intimal layer and the triggering of an inflammatory response. Accumulated low-density lipoprotein particles attached to the extracellular matrix suffer modifications and become pro-atherogenic, enhancing leucocyte recruitment and further transmigration across the endothelium into the intima. Infiltrated pro-atherogenic monocytes (mainly Mon2) differentiate into macrophages which acquire a specialized phenotypic polarization (protective/M1 or harmful/M2), depending on the stage of the atherosclerosis progression. Once differentiated, macrophages upregulate pattern recognition receptors capable of engulfing modified low-density lipoprotein, leading to foam cell formation. Foam cells release growth factors and cytokines that promote vascular smooth muscle cell migration into the intima, which then internalize low-density lipoproteins via low-density lipoprotein receptor-related protein-1 receptors becoming foam cells. As the plaque evolves, the number of vascular smooth muscle cells decline, whereas the presence of fragile/haemorrhagic neovessels and calcium deposits increases, promoting plaque destabilization. Disruption of this atherosclerotic lesion exposes thrombogenic surfaces rich in tissue factor that initiate platelet adhesion, activation, and aggregation, as well as thrombin generation. Platelets also participate in leucocyte and progenitor cell recruitment are likely to mediate atherosclerosis progression. Recent data attribute to microparticles a modulatory effect in the overall atherothrombotic process and evidence their potential use as systemic biomarkers of thrombus growth. This chapter reviews our current understanding of the pathophysiological mechanisms involved in atherogenesis, highlights platelet contribution to thrombosis and atherosclerosis progression, and provides new insights into how atherothrombosis may be prevented and modulated.


Author(s):  
Lina Badimon ◽  
Gemma Vilahur

Atherosclerosis is the main underlying cause of heart disease. The continuous exposure to cardiovascular risk factors induces endothelial activation/dysfunction which enhances the permeability of the endothelial layer and the expression of cytokines/chemokines and adhesion molecules. This results in the accumulation of lipids (low-density lipoprotein particles) in the intimal layer and the triggering of an inflammatory response. Accumulated low-density lipoprotein particles attached to the extracellular matrix suffer modifications and become pro-atherogenic, enhancing leucocyte recruitment and further transmigration across the endothelium into the intima. Infiltrated pro-atherogenic monocytes (mainly Mon2) differentiate into macrophages which acquire a specialized phenotypic polarization (protective/M1 or harmful/M2), depending on the stage of the atherosclerosis progression. Once differentiated, macrophages upregulate pattern recognition receptors capable of engulfing modified low-density lipoprotein, leading to foam cell formation. Foam cells release growth factors and cytokines that promote vascular smooth muscle cell migration into the intima, which then internalize low-density lipoproteins via low-density lipoprotein receptor-related protein-1 receptors becoming foam cells. As the plaque evolves, the number of vascular smooth muscle cells decline, whereas the presence of fragile/haemorrhagic neovessels and calcium deposits increases, promoting plaque destabilization. Disruption of this atherosclerotic lesion exposes thrombogenic surfaces rich in tissue factor that initiate platelet adhesion, activation, and aggregation, as well as thrombin generation. Platelets also participate in leucocyte and progenitor cell recruitment are likely to mediate atherosclerosis progression. Recent data attribute to microparticles a modulatory effect in the overall atherothrombotic process and evidence their potential use as systemic biomarkers of thrombus growth. This chapter reviews our current understanding of the pathophysiological mechanisms involved in atherogenesis, highlights platelet contribution to thrombosis and atherosclerosis progression, and provides new insights into how atherothrombosis may be prevented and modulated.


Author(s):  
Lina Badimon ◽  
Gemma Vilahur

Atherosclerosis is the main underlying cause of heart disease. The continuous exposure to cardiovascular risk factors induces endothelial activation/dysfunction which enhances the permeability of the endothelial layer and the expression of cytokines/chemokines and adhesion molecules. This results in the accumulation of lipids (low-density lipoprotein particles) in the extracellular matrix and the triggering of an inflammatory response. Accumulated low-density lipoprotein particles suffer modifications and become pro-atherogenic, enhancing leucocyte recruitment and further transmigration across the endothelium into the intima. Infiltrated monocytes differentiate into macrophages which acquire a specialized phenotypic polarization (protective or harmful), depending on the stage of the atherosclerosis progression. Once differentiated, macrophages upregulate pattern recognition receptors capable of engulfing modified low-density lipoprotein, leading to foam cell formation. Foam cells release growth factors and cytokines that promote vascular smooth muscle cell migration into the intima, which then internalize low-density lipoprotein via low-density lipoprotein receptor-related protein-1 receptors. As the plaque evolves, the number of vascular smooth muscle cells decline, whereas the presence of fragile/haemorrhagic neovessels increases, promoting plaque destabilization. Disruption of this atherosclerotic lesion exposes thrombogenic surfaces that initiate platelet adhesion, activation, and aggregation, as well as thrombin generation. Both lipid-laden vascular smooth muscle cells and macrophages release the procoagulant tissue factor, contributing to thrombus propagation. Platelets also participate in progenitor cell recruitment and drive the inflammatory response mediating the atherosclerosis progression. Recent data attribute to microparticles a potential modulatory effect in the overall atherothrombotic process. This chapter reviews our current understanding of the pathophysiological mechanisms involved in atherogenesis, highlights platelet contribution to thrombosis and atherosclerosis progression, and provides new insights into how atherothrombosis may be modulated.


Author(s):  
Jiefang Chen ◽  
Shulan Pi ◽  
Cheng Yu ◽  
Hanqing Shi ◽  
Yuxiao Liu ◽  
...  

Objective: Recent studies suggest that the P2Y12 (P2Y purinoceptor 12) receptor of vascular smooth muscle cells in atherosclerotic plaques aggravates atherosclerosis, and P2Y12 receptor inhibitors such as CDL (clopidogrel) may effectively treat atherosclerosis. It is imperative to identify an effective biomarker for reflecting the P2Y12 receptor expression on vascular smooth muscle cells in plaques. Approach and Results: We found that there was a positive correlation between the level of circulating sLRP1 (soluble low-density lipoprotein receptor-related protein 1) and the number of LRP1 + α-SMA + (α-smooth muscle actin), P2Y12 + , or P2Y12 + LRP1 + cells in plaques from apoE −/− mice fed a high-fat diet. Furthermore, activation of the P2Y12 receptor increased the expression and shedding of LRP1 in vascular smooth muscle cells by inhibiting cAMP (3'-5'-cyclic adenosine monophosphate)/PKA (protein kinase A)/SREBP-2 (sterol regulatory element binding transcription factor 2). Conversely, genetic knockdown or pharmacological inhibition of the P2Y12 receptor had the opposite effects. Additionally, CDL decreased the number of lesional LRP1 + α-SMA + cells and the levels of circulating sLRP1 by activating cAMP/PKA/SREBP-2 in apoE −/− mice fed a high-fat diet. Conclusions: Our study suggests that sLRP1 may be a biomarker that reflects the P2Y12 receptor level in plaques and has the potential to be an indicator for administering P2Y12 receptor inhibitors for patients with atherosclerosis.


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