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Finite element analysis of mechanics of neovessels with intraplaque hemorrhage in carotid atherosclerosis.

Lu J, Duan W, Qiao A - Biomed Eng Online (2015)

Bottom Line: Those neovessels closer to the carotid lumen undergo larger stress and stretch.Under the same conditions, the neovessels with larger curvature suffer greater stress and stretch.Neovessels surrounded by red blood cells undergo a much larger stretch.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Intraplaque hemorrhage is a widely known factor facilitating plaque instability. Neovascularization of plaque can be regarded as a compensatory response to the blood supply in the deep intimal and medial areas of the artery. Due to the physiological function, the deformation of carotid atherosclerotic plaque would happen under the action of blood pressure and blood flow. Neovessels are subject to mechanical loading and likely undergo deformation. The rupture of neovessels may deteriorate the instability of plaque. This study focuses on the local mechanical environments around neovessels and investigates the relationship between the biomechanics and the morphological specificity of neovessels.

Methods: Stress and stretch were used to evaluate the rupture risk of the neovessels in plaque. Computational structural analysis was performed based on two human carotid plaque slice samples. Two-dimensional models containing neovessels and other components were built according to the plaque slice samples. Each component was assumed to be non-linear isotropic, piecewise homogeneous and incompressible. Different mechanical boundary conditions, i.e. static pressures, were imposed in the carotid lumen and neovessels lumen respectively. Finite element method was used to simulate the mechanical conditions in the atherosclerotic plaque.

Results: Those neovessels closer to the carotid lumen undergo larger stress and stretch. With the same distance to the carotid lumen, the longer the perimeter of neovessels is, the larger stress and the deformation of the neovessels will be. Under the same conditions, the neovessels with larger curvature suffer greater stress and stretch. Neovessels surrounded by red blood cells undergo a much larger stretch.

Conclusions: Local mechanical conditions may result in the hemorrhage of neovessels and accelerate the rupture of plaque. The mechanical environments of the neovessel are related to its shape, curvature, distance to the carotid lumen and the material properties of plaque.

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Related in: MedlinePlus

Two samples of microscopic slices of plaque stained using H&E. (Left: S1; Right: S2). A: Fibrous cap; B: Fresh intraplaque hemorrhage; C: Vessel; D: Lipid core; E: Neovessels.
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Figure 1: Two samples of microscopic slices of plaque stained using H&E. (Left: S1; Right: S2). A: Fibrous cap; B: Fresh intraplaque hemorrhage; C: Vessel; D: Lipid core; E: Neovessels.

Mentions: The present study was performed using computational structural analysis based on two carotid plaque samples which were collected with endarterectomy for histopathological examination from Department of Neurology, Beijing Tian Tan Hospital, with patient consent obtained. One of them contains lipid core while another not. In the process of staining, the lipid core occurred shedding in S2 (sample 2). The patient's blood pressures were 159mmHg and 140mmHg at systole respectively. The samples were formalin-saline fixed, decalcified, embedded in paraffin and stained using hematoxylin and eosin (H&E), and then stained using Platelet endothelial cell adhesion molecule-1(PECAM-1/CD31) or Actin alpha, smooth muscle aorta (α-SMA). Both S1(sample1) and S2(sample 2) are decalcification. Figure 1 shows the histological slice stained using H&E. There are a great number of neovessels (Figure 1E) in the samples (which can be seen in the slice stained by α-SMA). All contours were manually traced by using Motic DSAssistant Lite (Motic, Inc., Amoy). Because it is a manual operation, we do not deny that there are some tiny random errors. Those contours are lumen borders and plaque components.


Finite element analysis of mechanics of neovessels with intraplaque hemorrhage in carotid atherosclerosis.

Lu J, Duan W, Qiao A - Biomed Eng Online (2015)

Two samples of microscopic slices of plaque stained using H&E. (Left: S1; Right: S2). A: Fibrous cap; B: Fresh intraplaque hemorrhage; C: Vessel; D: Lipid core; E: Neovessels.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4306113&req=5

Figure 1: Two samples of microscopic slices of plaque stained using H&E. (Left: S1; Right: S2). A: Fibrous cap; B: Fresh intraplaque hemorrhage; C: Vessel; D: Lipid core; E: Neovessels.
Mentions: The present study was performed using computational structural analysis based on two carotid plaque samples which were collected with endarterectomy for histopathological examination from Department of Neurology, Beijing Tian Tan Hospital, with patient consent obtained. One of them contains lipid core while another not. In the process of staining, the lipid core occurred shedding in S2 (sample 2). The patient's blood pressures were 159mmHg and 140mmHg at systole respectively. The samples were formalin-saline fixed, decalcified, embedded in paraffin and stained using hematoxylin and eosin (H&E), and then stained using Platelet endothelial cell adhesion molecule-1(PECAM-1/CD31) or Actin alpha, smooth muscle aorta (α-SMA). Both S1(sample1) and S2(sample 2) are decalcification. Figure 1 shows the histological slice stained using H&E. There are a great number of neovessels (Figure 1E) in the samples (which can be seen in the slice stained by α-SMA). All contours were manually traced by using Motic DSAssistant Lite (Motic, Inc., Amoy). Because it is a manual operation, we do not deny that there are some tiny random errors. Those contours are lumen borders and plaque components.

Bottom Line: Those neovessels closer to the carotid lumen undergo larger stress and stretch.Under the same conditions, the neovessels with larger curvature suffer greater stress and stretch.Neovessels surrounded by red blood cells undergo a much larger stretch.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Intraplaque hemorrhage is a widely known factor facilitating plaque instability. Neovascularization of plaque can be regarded as a compensatory response to the blood supply in the deep intimal and medial areas of the artery. Due to the physiological function, the deformation of carotid atherosclerotic plaque would happen under the action of blood pressure and blood flow. Neovessels are subject to mechanical loading and likely undergo deformation. The rupture of neovessels may deteriorate the instability of plaque. This study focuses on the local mechanical environments around neovessels and investigates the relationship between the biomechanics and the morphological specificity of neovessels.

Methods: Stress and stretch were used to evaluate the rupture risk of the neovessels in plaque. Computational structural analysis was performed based on two human carotid plaque slice samples. Two-dimensional models containing neovessels and other components were built according to the plaque slice samples. Each component was assumed to be non-linear isotropic, piecewise homogeneous and incompressible. Different mechanical boundary conditions, i.e. static pressures, were imposed in the carotid lumen and neovessels lumen respectively. Finite element method was used to simulate the mechanical conditions in the atherosclerotic plaque.

Results: Those neovessels closer to the carotid lumen undergo larger stress and stretch. With the same distance to the carotid lumen, the longer the perimeter of neovessels is, the larger stress and the deformation of the neovessels will be. Under the same conditions, the neovessels with larger curvature suffer greater stress and stretch. Neovessels surrounded by red blood cells undergo a much larger stretch.

Conclusions: Local mechanical conditions may result in the hemorrhage of neovessels and accelerate the rupture of plaque. The mechanical environments of the neovessel are related to its shape, curvature, distance to the carotid lumen and the material properties of plaque.

Show MeSH
Related in: MedlinePlus