Atherosclerotic Lesions Of Human Arteries Research Articles

MtDNA Mutations Linked With Myocardial Infarction

Aim: Myocardial infarction is one of clinical manifestations of coronary heart disease. In some cases, the cause of myocardial infarction may be atherosclerotic plaques which occurred in the human aorta. The association of mtDNA mutations with atherosclerotic lesions in human arteries was previously detected by our research group. The aim of the study was to detect mutations mtDNA associated with myocardial infarction. Methods: We analyzed samples of white blood cells collected from 225 patients with myocardial infarction and 239 control persons with no health complaints. DNA was isolated from the blood leukocyte samples. Then PCR-fragments of DNA were obtained. They contained the investigated regions of 11 mitochondrial genome mutations (m.5178C>A, m.3336T>C, 652delG, m.12315G>A, m.14459G>A, 652insG, m.14846G>A, m.1555A>G, m.15059G>A, m.3256C>T). An estimation of heteroplasmy level percent was carried out by an original method developed in our laboratory, based on pyrosequencing technology. The statistical processing was carried out using IBM SPSS Statistics, version 22.0. Results: According to the obtained results, three mutations of human mitochondrial genome correlated with myocardial infarction. A positive correlation was observed for mutation m.5178C>A. At the same time, a highly significant negative correlation with myocardial infarction was observed for mutation m.14846G>A. One single nucleotide substitution of m.12315G>A had a trend for negative correlation. Conclusions: Mutation m.5178C>A can potentially be useful for creating molecular/cellular models for studying the mechanisms of myocardial infarction. Meanwhile m.14846G>A and m.12315G>A may be useful for developing gene therapy. This study was supported by Russian Science Foundation (Grant # 20-15-00364).

Matrix stiffness regulates SMC functions via TGF-β signaling pathway

The stiffness change of the vessel wall is involved in many pathological processes of the blood vessel. However, how stiffness changes regulate vascular cell phenotype is not well understood. In this study, we investigated the effects of matrix stiffness on the phenotype and functions of vascular smooth muscle cells (SMCs). SMCs were cultured on the matrices with the stiffness between 1 and 100 kPa. The expression of contractile markers calponin-1 (CNN1) and smoothelin (SMTN) increased with stiffness; in contrast, the expression of synthetic markers osteopontin (OPN) and epiregulin (EREG) were the highest on the soft surface (1 kPa). In addition, matrix metalloproteinase 2 (MMP-2) was significantly upregulated on 1-kPa surface. Consistently, the stiffness of atherosclerotic lesions in human arteries decreased by up to 10 folds compared to normal area (>40 kPa), which was accompanied by a decrease of CNN1 expression and collagen content and an increase of OPN and MMP-2 in the area of lipid deposition. Furthermore, the phosphorylation of Smad2/3 increased with matrix stiffness; when TGF-β signaling pathway was inhibited, the stiffness effects on the SMCs were reversed. Our findings suggest that matrix stiffness regulates SMC phenotype and matrix remodeling through TGF-β signal pathway. This study unravels a mechanobiological mechanism in vascular remodeling, and will help us develop strategies for vascular tissue engineering, disease modeling and therapies.

Mtdna Mutations Associated With Myocardial Infarction

Background and Aims: Myocardial infarction is one of clinical manifestations of coronary heart disease. In some cases, the cause of myocardial infarction may be atherosclerotic plaques which occurred in the human aorta. The association of mtDNA mutations with atherosclerotic lesions in human arteries was previously detected by our research group. The aim of the study was to detect mutations mtDNA associated with myocardial infarction.

Mitochondrial Genome Mutations Associated with Myocardial Infarction

Myocardial infarction is one of the clinical manifestations of coronary heart disease. In some cases, the cause of myocardial infarction may be atherosclerotic plaques which occurred in the human aorta. The association of mtDNA mutations with atherosclerotic lesions in human arteries was previously detected by our research group. In this study, we used samples of white blood cells collected from 225 patients with myocardial infarction and 239 control persons with no health complaints. DNA was isolated from the blood leukocyte samples. Then, PCR fragments of DNA were obtained. They contained the investigated regions of 11 mitochondrial genome mutations (m.5178C>A, m.3336T>C, m.652delG, m.12315G>A, m.14459G>A, m.652insG, m.14846G>A, m.13513G>A, m.1555A>G, m.15059G>A, m.3256C>T). According to the obtained results, three mutations of the human mitochondrial genome correlated with myocardial infarction. A positive correlation was observed for mutation m.5178C>A. At the same time, a highly significant negative correlation with myocardial infarction was observed for mutation m.14846G>A. One single-nucleotide substitution of m.12315G>A had a trend towards negative correlation. These mutations can potentially be useful for creating molecular/cellular models for studying the mechanisms of myocardial infarction and designing novel therapies. Moreover, these mutations can possibly be used for diagnostic purposes.

Abstract 134: Extracellular ATP Inhibits Natural Killer Cell Recruitment in Inflamed Tissues and Protects Endothelial Cells From NK-Mediated Vascular Injury

Background: Natural killer cells (NK) represent the main source of IFN-gamma that contributes to atherosclerotic plaque progression and instability. Fractalkine (CX3CL1) expressed by endothelial cells (ECs) mediate NK recruitment and elicit NK-mediated ECs killing. Moreover high CX3CL1 mRNA expression has been found in advanced atherosclerotic lesions of human arteries as well as in the deep intima of diabetic patients. Nucleotides can be massively released in the extracellular space by ECs under shear stress, activated platelets and injured cells and stimulate purinergic receptors expressed in different cell types including NK. Hypothesis: that extracellular nucleotides modify NK responses to CX3CL1 or SDF-1 (CXCL12) and their ability to mediate vascular injury. Methods: NK were isolated by negative immunomagnetic selection from peripheral blood of healthy blood donors and P2 receptor genes expression pattern studied by RT-PCR. NK chemotaxis was measured by transwell cell culture system followed by flow cytometric analysis of migrated cells. NK were co-cultured with HUVEC cells to analyze NK-mediated ECs killing. Results: we show for the first time that NK express P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, P2Y14 and P2X1, P2X4, P2X7 receptors. Neither ATP or UTP alone induced NK cell migration. However ATP but not UTP increased non-directional cell movement (chemokinesis). This effect was mimicked by the cell permeable cyclic AMP analogue 8-Br-cAMP and was dependent on Protein kinase A activity since it was blocked by the specific inhibitor H89. In addition, ATP but not UTP, inhibited NK cell chemotaxis to CX3CL1 whereas expression for CXCR4 and migration following CXCL12 stimulation were increased. Moreover the NK-mediated killing of HUVEC cells was downregulated following exposure to extracellular ATP. Conclusion: CX3CL1 has been shown to participate to leukocyte adhesion to ECs and extravasation. In addition membrane bounds form of CX3CL1 expressed by ECs triggers NK cytotoxicity. ATP release from endothelial cells upon shear stress and in inflammatory states might represent a protective mechanism from NK cell-mediated cytotoxicity and point out P2 purinergic receptors as novel potential therapeutic targets.

Immunohistochemical localization of glutathione peroxidase, a lipid peroxides scavenger, in atherosclerotic lesions of human arteries

The localization of glutathione peroxidase (GSH-PO) in the human arteriosclerotic lesions was investigated by immunohistochemical methods. GSH-PO is an enzyme that effectively reduces lipid peroxides. It is also known that its synthesis is significantly increased by lipid peroxides, the substrate of the enzyme. Accordingly, the increased expression of GSH-PO would indicate the promotion of lipid peroxidation in the site. Immunohistochemistry for Apo-B protein, the major protein component of plasma low density lipoprotein (LDL), was also performed to show the amount of plasma LDL permeation and deposition on the arterial wall. Atheromatous plaques contained numerous GSH-PO positive cells with foamy cytoplasm, while normal arterial walls were almost devoid of GSH-PO positive cells. Immunoelectron microscopically, the GSH-PO reaction products were observed diffusely in the cytoplasm of these cells. The deposition of Apo-B was closely related to the localization of GSH-PO positive cells in the atheromatous lesions. These findings suggest that the lipid peroxidation that surpasses the protective actions of GSH-PO may cause foamy change of smooth muscle cells and macrophages to ultimately form atherosclerotic lesions.