Atherosclerosis In Human Arteries Research Articles

Agext and Its Active Compounds as Potential Therapeutic Prevention against Atherosclerosis and Cardiovascular Disease

Advanced Glycation End-Products (AGEs) have been implicated in the chronic complications of Diabetes Mellitus (DM) and play an important role in the pathogenesis of atherosclerosis in human arteries. The main active compounds found in Aged Garlic Extract (AGExt) are S-Allyl Cysteine (SAC), N-Acetylcysteine (NAC) and S-allyl Mercaptocysteine (SAMC) and have powerful protective effects against oxidative stress and inhibit cellular damage by AGEs. Aims: To explore the effect of AGExt on the development of atherosclerosis also investigated the endothelial protective effects of AGExt, using Human Coronary Artery-Derived Endothelial Cells (HCAEC). The use of an optimised mixture of the above compounds required to obtain and provide maximal beneficial effects against oxidative stress, cell apoptosis and protein glycation. Results: AGExt has protective effects against the cellular damage of HCAEC. In addition, the in vivo study accessed the activity of SAC and NAC to reduce the severity of atherosclerosis formation in Apolipoprotein (ApoE-/-) DM model mouse. The compounds of AGExt in vitro had strong protective actions against the AGEs induced damage to ECs even at low concentrations (100 ng/ml). Such low concentrations may have therapeutic usefulness in patients with diabetes.

Impact of Stenosis Geometry on Blood Flow Behavior in Human Artery

Atherosclerosis in human arteries affects the blood flow behaviour in different ways and sometimes leads to fatal diseases. This study is focused on the impact of the elasticity of human arteries and the geometry of stenosis on non-Newtonian blood flow across the constricted arteries. The mathematical analysis is carried out using MatLab software. The elastic nature of human arteries and the non-Newtonian nature of blood are described under the power-law, Herschel-Bulkley and Casson model. The numerical derivations for blood flow velocity, volume flow rate and wall shear stress are derived for all three types of the model under consideration and results are also depicted graphically. The influence of elasticity, flow index, yield stress and geometry of stenosis on the blood flow is examined. Power-law model gives higher velocity as compared to Herschel-Bulkley model for the fixed magnitude of flow index 𝑛. It is observed that in the constricted region, the volume flow rate amplifies with the increasing value of stenosis shape parameter 𝑚 for the fixed magnitude of flow index 𝑛. The height of stenosis has a diminishing effect on the flow rate. A comparative analysis of the outcomes of the present study and that of the other published work is carried out for authentication.

Mathematical investigation of aetiology and pathogenesis of atherosclerosis in human arteries

To understand the role of medically significant hemodynamic wall parameters in the pathogenesis of vascular diseases, pulsatile blood flow in large human arteries of systemic, pulmonary and coronary circulation is investigated by mathematical modelling. To be medically realistic, the pressure gradient waveforms reported in the cardiology literature for the arteries considered are digitised and developed in Fourier series (McDonald's model). Three objectives of the article are to (i) compare qualitatively and quantitatively the pulsatile blood flow between the parallel plate and circular geometry, (ii) compare the hemodynamic wall parameters in the three major circulations mentioned above to gain new medical or physiological insights and (iii) understand if slip at the wall has significant influence on the hemodynamic wall parameters. Our model is reliable since the results obtained here through exact solutions are in great agreement with those reported in the medical literature. New insights gained from our study, documented here for the first time in the hemodynamic literature, are as follows: parallel plate geometry approximation is not reliable quantitatively; larger the radius (Womersley number), larger is the value of relative residence time and hence, higher the probability for vascular diseases; none of the commonly employed interface conditions are suitable for the hemodynamic studies. Comparing our results with earlier studies, we recommend that future research should focus on developing an interface condition exclusively for haemodynamics. We support the recent understanding that low wall shear stress and high oscillatory shear index need not co-locate. We have rendered new physiological insight for this result.

Mathematical investigation of aetiology and pathogenesis of atherosclerosis in human arteries

To understand the role of medically significant hemodynamic wall parameters in the pathogenesis of vascular diseases, pulsatile blood flow in large human arteries of systemic, pulmonary and coronary circulation is investigated by mathematical modelling. To be medically realistic, the pressure gradient waveforms reported in the cardiology literature for the arteries considered are digitised and developed in Fourier series (McDonald's model). Three objectives of the article are to (i) compare qualitatively and quantitatively the pulsatile blood flow between the parallel plate and circular geometry, (ii) compare the hemodynamic wall parameters in the three major circulations mentioned above to gain new medical or physiological insights and (iii) understand if slip at the wall has significant influence on the hemodynamic wall parameters. Our model is reliable since the results obtained here through exact solutions are in great agreement with those reported in the medical literature. New insights gained from our study, documented here for the first time in the hemodynamic literature, are as follows: parallel plate geometry approximation is not reliable quantitatively; larger the radius (Womersley number), larger is the value of relative residence time and hence, higher the probability for vascular diseases; none of the commonly employed interface conditions are suitable for the hemodynamic studies. Comparing our results with earlier studies, we recommend that future research should focus on developing an interface condition exclusively for haemodynamics. We support the recent understanding that low wall shear stress and high oscillatory shear index need not co-locate. We have rendered new physiological insight for this result.

Differential distribution of vasa vasorum in different vascular beds in humans

Objective Vasa vasorum (VV) have been implicated to play a role in the pathogenesis of atherosclerosis. This study was designed to describe the distribution of VV density in different vascular beds in humans and to investigate the association between VV density and the known distribution of atherosclerosis in human arteries. Methods Forty-two human arteries, harvested at autopsy or after explantation, were analyzed by three-dimensional microscopic-computed tomography (micro-CT). VV density, endothelial-surface-fraction (Σ VV endothelial-surface-area/vessel-wall-volume) and vascular-area-fraction (Σ VV area/vessel-wall-area) were calculated for coronary, renal and femoral arteries. Representatively five coronary, renal and femoral arteries were stained for endothelial cells (von Willebrand-Factor), macrophages (CD68), vascular endothelial growth factor (VEGF) and collagen (Sirius Red). Results Coronary arteries showed a higher VV density compared to renal and femoral arteries (2.12 ± 0.26 n/mm 2 versus 0.61 ± 0.06 n/mm 2 and 0.66 ± 0.11 n/mm 2; P < 0.05 for both) as well as a higher endothelial-surface-fraction and vascular-area-fraction. Histology showed a positive correlation between histologically derived VV density and CD68-positive cells/area ( r = 0.54, P < 0.01), VEGF-immunoreactivity/area ( r = 0.55, P < 0.01) and a negative correlation between VV density and collagen I content ( r = 0.66, P < 0.05). Conclusion This micro-CT study highlights a higher VV density in coronary than in peripheral arteries, supporting the relation between VV density and the susceptibility to atherosclerosis in different vascular beds in humans.

Raman spectroscopy for diagnosis of atherosclerosis: a rapid analysis using neural networks

Near-infrared Raman spectroscopy (NIRS) is one of the novel techniques that has a potential for in vivo diagnosis of atherosclerosis in human arteries. For such real time clinical applications, a rapid collection and analysis of the data is needed. One of the major problems with the fast data collection is that the noise generated by the detector has the same level as the Raman signal from the tissue, which makes the analysis difficult. In this work, NIRS measurements have been carried out on a total of 60 samples from human coronary arteries. Raman spectral data with the correlated histopathological analysis have been used as a basis to stimulate the cases of severe noise conditions. The main objective of this paper is the comparison of different processing algorithms that have been developed based on either wavelet transformation or principal component analysis for compressing the Raman spectral vectors and a rapid data classification based on different neural network architectures. The developed algorithms found to provide promising diagnosis results with classification errors smaller than 5%, even in the cases of Raman data with collection times as small as 20 ms. It has been concluded that the developed algorithms would be very much useful in the development of Raman spectroscopy systems for in vivo biological applications.

Waist Circumference, Visceral Obesity, and Cardiovascular Risk

Waist Circumference, Visceral Obesity, and Cardiovascular Risk

Detection of Atherosclerosis in Human Artery by Mid-Infrared Attenuated Total Reflectance

Atherosclerosis, with its clinical sequelae, is the most common cause of death in the United States. In the atherosclerotic process, the innermost layer of the arterial wall becomes thickened due to cellular proliferation and the accumulation of cholesterol and lipids. The primary means of characterizing atherosclerotic lesions is histochemical analysis, in which arterial wall cross sections are studied under a microscope. This method requires removal of arterial tissue and is therefore not suited to arterial wall characterization in vivo. Consequently, histopathological information is rarely available clinically for selecting an appropriate therapy. To overcome this limitation, researchers are exploring several nondestructive techniques, such as ultrasound, UV-visible absorption, and UV-visible fluorescence, as alternative methods of probing arterial wall composition and structure.