Molecular Pathogenesis and the Possible Role of Mitochondrial Heteroplasmy in Thoracic Aortic Aneurysm.

Thoracic aortic aneurysm (TAA) is a life-threatening condition associated with high mortality, in which the aortic wall is deformed due to congenital or age-associated pathological changes. The mechanisms of TAA development remain to be studied in detail, and are the subject of active research. In this review, we describe the morphological changes of the aortic wall in TAA. We outline the genetic disorders associated with aortic enlargement and discuss the potential role of mitochondrial pathology, in particular mitochondrial DNA heteroplasmy, in the disease pathogenesis.

Immunogenic lipid markers of atherosclerosis in type 2 diabetic patients on program haemodialysis.

AIM: Determination of desialized apolipoprotein-B-100 (apoB-100) and lipoprotein-containing circulating immune complexes in patients with chronic kidney disease (CKD) in program hemodialysis with type 2 diabetes mellitus. MATERIALS AND METHODS: We examined 81 patients with CKD (50 men / 31 women) treated with program hemodialysis, of which 36 (17/19) with type 2 diabetes mellitus, 45 (33/12) non-diabetic patients. The levels of total cholesterol, triglycerides and desialylated apoB-100 in blood plasma and lipoprotein-containing circulating immune complexes. A color duplex scan of brachiocephalic arteries was used to assess the extent of development of atherosclerosis with the determination of the thickness of the intima-medial complex. RESULTS: Patients with diabetes had high values of total cholesterol, triglycerides (p<0.05). Duplex scan of brachiocephalic arteries showed an increase in the thickness of intima-medial complex in all patients for program hemodialysis, however, in patients with diabetes, the thickness was 13% higher (p<0.05). In patients with diabetes, plaques with stenosis up to 50% prevail, compared with non-diabetic patients, p<0.05. The incidence was significantly higher for desialized apoB-100 by 46% in patients with diabetes on hemodialysis compared non-diabetic patients (p<0.05). An increase in the level of lipoprotein-containing circulating immune complexes by 39%, (p<0.05) in patients with diabetes mellitus was observed, compared with patients non-diabetic patients. The correlation between desialized apoB-100 and duplex scan of brachiocephalic arteries parameters (r=0.325), as well as between the cholesterol level and stenosis up to 50% (r=0.465) in patients with diabetes mellitus, was found to be of medium strength. The patients with diabetes and CKD, myocardial infarction developed 79% more often than in patients without diabetes (p<0.05). Thus, immunogenic lipid markers of atherosclerosis can be considered both as mechanical factors of atherogenesis and diagnostic and prognostic characteristics in type 2 diabetic patients with impaired renal function and chronic renal insufficiency. CONCLUSION: Accelerated development of atherosclerosis with diabetes and CKD, confirmed with the help of duplex scan of brachiocephalic arteries, may be associated with an increase in the level of modified low density lipoprotein.

[Study of mitochondrial dysfunction using cytoplasmic hybrid].

Aim. This review article describes literature sources devoted to the investigation of mitochondrial dysfunction using cytoplasmic hybrids (cybrids). The presented studies were carried out on cultures of cybrid cell lines HL60, MOL T-4, A549, 143B, HeLa, Arpe-19, HEK-293, SH-SY5Y and NT2. According to the analysis of scientific world literature, some of the most promising models for studying mitochondrial dysfunction are cell cultures without mitochondria (rho0) and cytoplasmic hybrids containing one or several mutations of mitochondrial genome. In the review scientific researches on studying biochemical and molecular cellular pathological processes in cybrid cells in various human diseases such as Alzheimer's disease and mild cognitive impairment, MERRF and MELAS syndromes, Leber's optic atrophy and Parkinson's disease were considered. Material dedicated to cybrids as potential models for the study of treatment possibilities was presented separately. Conclusion. The analyzed in the review rho0-cell cultures and cybrid lines containing mtDNA mutations may be models for the study of mitochondrial genome dysfunctions, biochemical and molecular cellular pathological processes. It is worth noting that in various cell cultures, similar tendencies are observed in functional activity changes of rho0-cell and cybrids compared with native cell lines. For example, such tendencies as reduction of oxygen consumption level, morphological changes of mitochondrial structure, resistance to apoptosis, reduction of ATP consumption level, increase in glucose consumption, activity deterioration of some respiratory chain complexes.

Phytoestrogen-Rich Natural Preparation for Treatment of Climacteric Syndrome and Atherosclerosis Prevention in Perimenopausal Women.

The present study evaluated the risks and benefits of phytoestrogen treatment in healthy perimenopausal women in relation to the dynamics of climacteric syndrome and progression of atherosclerosis. Study participants were treated with placebo or phytoestrogen-rich natural preparation Karinat based on grape (Vitis vinifera) seeds, green tea (Camellia sinensis) leaves, hop (Hunulus lupulus) cone powder and garlic (Allium sativum) powder. The dynamics of climacteric syndrome was evaluated by Kupperman Index and Utian Quality of Life Scale. Atherosclerosis progression was evaluated by measuring carotid intima-media thickness. Significant changes of climacteric syndrome's severity in both Karinat and placebo groups (p = 0.005 and p = 0.001) were obtained after 24 months of follow-up. Detailed analysis of Kupperman Index suggested that Karinat possessed a significant effect on nervousness (p = 0.010), weakness (p = 0.020) and formication (p = 0.010). A significant improvement of medical (p = 0.070) and emotional (p = 0.060) components of Kupperman Index and Utian Quality of Life Scale was also observed in Karinat group. However, difference in carotid intima-media thickness between the two groups was not statistically significant at follow-up. A slight positive effect of phytoestrogens on climacteric syndrome manifestations was demonstrated in this study. Karinat can be used for alleviation of climacteric syndrome and cardiovascular disease prevention in perimenopausal women. Copyright © 2017 John Wiley & Sons, Ltd.

Lipid composition of circulating multiple-modified low density lipoprotein.

Atherogenic modified low- density lipoprotein (LDL) induces pronounced accumulation of cholesterol and lipids in the arterial wall, while native LDL seems to lack such capability. Therefore, modified LDL appears to be a major causative agent in the pathogenesis of atherosclerosis. Possible modifications of LDL particles include changes in size and density, desialylation, oxidation and acquisition of negative charge. Total LDL isolated from pooled plasma of patients with coronary atherosclerosis, as well as from healthy subjects contains two distinct subfractions: normally sialylated LDL and desialylated LDL, which can be isolated by binding to a lectin affinity column. We called the desialylated LDL subfraction circulating modified LDL (cmLDL). In this study, we focused on lipid composition of LDL particles, analysing the total LDL preparation and two LDL subfractions: cmLDL and native LDL. The composition of LDL was studied using thin-layer chromatography. We found that cmLDL subfraction had decreased levels of free and esterified cholesterol, triglycerides, phospholipids (except for lysophosphatidylcholine) and sphingomyelin in comparison to native LDL. On the other hand, levels of mono-, and diglycerides, lysophosphatidylcholine and free fatty acids were higher in cmLDL than in native LDL. Our study demonstrated that lipid composition of cmLDL from atherosclerotic patients was altered in comparison to healthy subjects. In particular, phospholipid content was decreased, and free fatty acids levels were increased in cmLDL. This strengthens the hypothesis of multiple modification of LDL particles in the bloodstream and underscores the clinical importance of desialylated LDL as a possible marker of atherosclerosis progression.

[The heteroplasmy level of some mutations in gene MT-CYB among women with asymptomatic atherosclerosis].

Atherosclerosis is a polygenic socially significant disease whose risk factors include coronary heart disease, diabetes, hypertension, and myocardial infarction. According to the literature, mutations m.14846G>A (G34S), m.15762G>A (G339Q), m.15084G>A (W113Ter), and m.15059G>A (G190Ter) of cytochrome B gene (MT-CYB) are associated with mitochondrial myopathies, myoglobinuria, and exercise intolerance. Preliminary studies carried out by the authors made it possible to discover an association of certain mitochondrial genome mutations with atherosclerotic lesions of aortic intima in people who died as a result of an accident or sudden death. The most interesting seemed to be the data on the association of mutations m.14846G>A and m.15059G>A of the cytochrome B gene with lipofibrous aortic plaques, because these mutations affect the mitochondrial respiratory chain enzyme. Defects in the given chain may be the reason for the launch of pathogenic mechanisms in the human body. Owing to the fact that mutations in the mitochondrial genome are inherited by the maternal type, it was decided to analyze cytochrome B gene mutations in a sample of female volunteers from Moscow oblast. According to the findings, mutations m.14846G>A and m.15059G>A are highly significantly associated with atherosclerotic lesions of the carotid arteries: m.14846G>A is antiatherogenic and m.15059G>A is proatherogenic.

Susceptibility of monocytes to activation correlates with atherogenic mitochondrial DNA mutations.

We have recently evaluated the susceptibility of circulating monocytes to pro- and anti-inflammatory activation comparing samples from healthy individuals and patients with asymptomatic carotid atherosclerosis. Surprisingly, we found a dramatic individual difference in susceptibility to activation between monocytes isolated from the blood of different subjects, regardless of the presence or absence of atherosclerosis. In the present study the monocyte susceptibility to pro-inflammatory activation was evaluated in comparison with mitochondrial DNA mutations that have previously been shown to correlate with the degree of carotid atherosclerosis assessed by intima-media thickness. Among the mutations associated with atherosclerosis were both homoplasmic (absence or presence of the mutation) or heteroplasmic (different proportions of mutant allele). It was found that two homoplasmic mutations, A1811G and G9477A, tended to correlate with the degree of monocyte susceptibility to activation. At the same time, the mutation G9477A inversely correlated with the degree of monocyte activability, that is, the mutation was more prevalent in monocytes with a low degree of activability. We have found that at least three heteroplasmic mutations of mtDNA (G14459A, A1555G, G12315A) earlier known to be associated with human atherosclerosis, also correlate with proinflammatory activation of circulating human monocytes. We suggest that some mutations can cause mitochondrial dysfunction, which in turn may lead to changes of macrophage activities in atherosclerosis.

[Conventional and novel cardiovascular risk factors and predisposition to the development of atherosclerosis].

This population-based cross-sectional study included 472 apparently healthy study participants with an increased risk of cardiovascular disease, including 300 patients with hypercholesterolemia. To assess the susceptibility to the development of atherosclerosis, an ultrasonic evaluation of common carotid arteries was used. It has been confirmed that there exists the geographical gradient of carotid intima-media thickness (cIMT), and it has been shown that this gradient is highly correlated th the known gradient of cardiovascular mortality. It was found that the combination of conventional cardiovascular risk factors can help explaining only 21% variability of cIMT, the marker of generalized atherosclerosis. It was found that a predisposition to atherosclerosis, as measured by a pathological increase in cIMT, should be due to the interaction not only conventional cardiovascular risk factors, but also to genetic and environmental factors.

[Analysis of mitochondrial haplogroups in persons with subclinical atherosclerosis based on high-throughput mtDNA sequencing].

Genetic predisposition plays an important role among other risk factors in multifactorial socially significant diseases such as atherosclerosis and its clinical manifestations. This pilot study was aimed to identify the relationship between the type of mitochondrial haplogroup and the risk of subclinical atherosclerosis in humans. For accurate detection of mitochondrial haplogroups, high-throughput sequencing of the mitochondrial genome using the Roche 454 technology was carried out. The results have shown that in Russian population, the belonging to haplogroup H is associated with an increased risk of atherosclerosis, but belonging to haplogroups T and U--with reduced risk. The data obtained can be used to assess individual risk of atherosclerosis and for further studies on the role of mitochondrial genome mutations in the development of atherosclerosis and its clinical manifestations.

Pluronics suppress association of low-density lipoproteins inducing atherogenesis.

We studied the effect of pluronics P85, L61, and F68 with different hydrophilic-lipophilic characteristics on association of LDL. It was found that pluronics with pronounced hydrophobic properties (P85 and L61) in concentrations close to or surpassing the critical concentration of micelle formation inhibited LDL association, while hydrophilic pluronic F68 in all concentrations had no effect on LDL association.

Coordination in gene expression during atherogenesis.

General tendencies in the regulation of gene expression during atherogenesis were investigated using correlation analysis for 34 mRNA species of several functional groups. The contents of mRNA were measured by quantitative PCR in samples of human aortal intima containing no lesions or atherosclerotic lesions of types I (initial lesions), II (fatty streaks), and Va (fibroatheromas). The coupling between mRNA contents in lesions and the same mRNAs in intact tissue was found to descend in the course of the disease progression. The data are in accordance with the opinion that successive morphologic types of atherosclerotic lesions correspond to steps of atherogenesis. In addition, the contents of individual mRNA species could correlate with each other within the given sample type, the extent of this coupling rising along with the disease progression. The exception from this rule was a collapse in coupling for several functional groups of mRNA in lesions of type I. This collapse could indicate special position of these lesions in pathogenesis. Statistically significant correlations between mRNAs found in samples of all four types comprised in total about 50% of all possible correlations. 66% of these correlations were conservative, i.e. observed in at least two sample types. By coupling-strength, the studied mRNAs could be divided into four clusters whose composition significantly varied along with the disease progression. The disease progression was also associated with decline in number of regulatory factors that determine coordination in expression of the analyzed genes.

Changes in levels of gene expression in human aortal intima during atherogenesis.

Changes in the contents of 36 mRNAs species related to lipid turnover, inflammation, metabolism and the action of sex hormones in samples of aortal intima along the "intact tissue - lesions of type I - lesions of type II - lesions of type Va" sequence were analyzed using quantitative PCR. The expression of several mRNAs coding for components of the vesicular transfer and lipid turnover machinery was found to be resistant to atherogenesis or even decline in the course of atherogenesis. Decrease in expression was also recorded for steroid sulfatase, androgen receptor, and low density lipoprotein receptor mRNAs. However, the contents of the majority of other mRNA species increased gradually during disease progression. The earliest changes found as early as in lesions of type I were characteristic for estrogen sulfotransferase, apolipoprotein E, scavenger receptor SR-BI, collagen COL1A2, as well as chemokine CCL18 mRNAs. The contents of several mRNAs in intact tissue and atherosclerotic injuries had gender differences. Additionally, responses of two mRNAs, for aromatase and sterol regulatory element binding protein 2, to atherosclerotic lesion were also sex-differentiated. The contents of the majority of analyzed mRNAs in peripheral blood monocyte-derived macrophages were higher than in intact aorta. The correlations found in atherosclerotic lesions between mRNA species that predominant in macrophages and those expressed at comparable levels in macrophages and intact aorta or mainly in aorta suggest that the observed rise in the content of the majority of mRNAs during atherogenesis is determined by increase in expression in resident cells. The data suggest that the revealed absence of homeostatic regulation of expression of a number of genes associated with vesicular transfer and lipid turnover can serve as one of the reasons for lysosomal function insufficiency that leads to foam cell formation in atheroma. The observed sex differences in expression of a number of mRNAs suggest that estrogens in women perform their atheroprotective effects starting with predisposition to the disease and finishing with advanced stages of the pathologic process.

[Interaction of native and modified low density lipoprotein with intimal cells in atherosclerotic lesion].

In the present review we focus on the major cellular and molecular processes leading to the formation and accumulation of foamy cells: increased transmigration of monocytes into sub-endothelial sites of inflammation, activation of macrophages, modifications of lipoproteins, different types of uptake of native and associated lipoproteins (endocytosis, phagocytosis, and less-investigated--patocytosis), as well as participation of different molecular systems in the reverse cholesterol transport in macrophages. Special attention is given to the recent data indicating that scavenger receptors participate not only in the uptake of modified lipoproteins, but also in the reverse cholesterol transport. In conclusion, we discuss most relevant open questions in our understanding of the mechanism and functional consequences of macrophage/lipoprotein interactions: which receptor systems are used for the recognition and internalisation of aggregated lipoproteins, what are the mechanisms of intracellular processing of associated lipoproteins, and how associated lipoproteins affect functional programming of macrophages.

Effect of sex hormones on levels of mRNAs coding for proteins involved in lipid metabolism in macrophages.

The effects of sex hormones estradiol (E2), testosterone (Te), and 5α-dihydrotestosterone (DT) on cholesterol accumulation induced by modified low density lipoproteins (LDL) in macrophages differentiated from human peripheral blood monocytes and on the levels of mRNAs coding for proteins involved in lipid metabolism have been studied. All three hormones at physiological concentrations (1 nM) are capable of reducing cholesterol accumulation in cells. The treatment of cells with modified and native (not inducing cholesterol accumulation) LDL results in similar alterations in the expression of several mRNAs aimed primarily at homeostatic regulation of lipid metabolism. These alterations depend on the sex of macrophage donors and in some cases are even reversed in cells obtained from male and female donors. The cells not treated with modified LDL have no significant gender differences in the expression of the examined mRNAs. Hormones, either independently or in combination with the modified LDL, influence the levels of some mRNAs, and each hormone shows an individual range of effects. Correlation analysis of changes in mRNA content in the cells showed that the hormones may interfere with coordination of gene expression. Hormone action leads to: (1) reduced coupling of the content of individual mRNAs with their initial levels in the control cells; (2) reduced coupling of different mRNA levels; (3) regrouping of mRNAs between the clusters; and (4) changes in the number of factors that determine the correlation links between mRNAs. The data show that sex hormones may have impact on the level of expression of certain genes and, in particular, on the coordination of gene expression in macrophages.

[Direct antiatherosclerotic therapy: possible approaches, results of clinical trials].

The paper discusses the main approaches to slowing the progression and epy regression of atherosclerosis. Lipid and non-lipid treatment of atherosclerosis described. The results of clinical studies of the effect of antiatherosclerotic agents are analyzed. The main indicator is the thickness of the intima-media complex of the carotid arteries as measured by ultrasonography.

[Cholesterol of circulating immune complexes as biomarker of atherosclerosis].

In the present 2-years prospective study, the diagnostic and prognostic significance of immune cholesterol was assessed in 98 asymptomatic men aged 40-74 with early atherosclerosis. The rate of carotid atherosclerosis progression was estimated by high-resolution B-mode ultrasonography as the increase in carotid intima-media thickness (IMT) of common carotid arteries. The patients with elevated baseline levels of immune cholesterol were characterized by significantly higher levels of total and LDL (low density lipoproteins) cholesterol as well as significantly increased mean IMT of common carotid arteries. Among all baseline lipid parameters, only immune cholesterol and LDL cholesterol were contingent with the extent of early carotid atherosclerosis (p=0.042 and p=0.049, respectively) and had the highest levels of relative risk and odds ratio. Carotid atherosclerosis progression was characterized by slow IMT increase at a rate of 0.029 +/- 0.011 mm per two years over the mean baseline IMT of 0.939 +/- 0.015 mm (p=0.028). A significant IMT increase was registered in 53.1% (n=52) patients, IMT significant reduction was observed in 21.4% (n=21) patients. The increased level of immune cholesterol along with total serum cholesterol and LDL cholesterol had rather high prognostic significance with the respect of atherosclerosis progression. The normal level of immune cholesterol (below than 16.0 mg/ml) was the only lipid parameter that predicted the absence of carotid atherosclerosis progression for two following years at prognostic value of 78.3%. The results of the study allow assuming that immune cholesterol level may be employed not only as a marker of early atherosclerosis, but also has a sufficient prognostic value for clinical implications.

[Study of intima-medial thickness (IMT) of the carotid arteries as an indicator of natural atherosclerosis progress in Moscow population].

A cross-sectional study of intima-medial thickness (IMT) of the carotid arteries in men and women in different age groups was performed as well as a prospective study of the dynamics of carotid IMT changes. It was shown that at the ages 40-70 years IMT is higher in men then in women, but at age after 70 such difference disappears due to acceleration of atherosclerosis progression in women, which starts after 58. Atherosclerosis progresses at uneven rate, both in men and women, and there are age periods characterized with different rate of IMT progression. In women, the most active progression of atherosclerosis starts 8 years later than in men, and is associated with the onset of late menopausal period.

[Cultured cell systems for revelation of new drugs antiatherosclerotic effects and their mechanisms investigation].

Cultured cell models have been developed to study the cholesterol efflux from the arterial wall as an integral indicator of reverse cholesterol transport. The models and the results of in vivo and ex vivo experiments can be used to propose new antiatherosclerotic drugs and elucidate their mood of action.

Contents of mRNAs encoding endosome/lysosome components in normal human aorta and in stage II of atherogenesis: a hidden regulation.

Contents of mRNAs encoding endosome/lysosome components EEA1, Rab5a, Lamp1, Lamp2, p62 (SQSTM1), and CD63 were measured by quantitative PCR and compared in intact fragments of human aorta and in aorta fragments with atherosclerotic lesions of stage II (fatty streaks) of the same donors. During atherogenesis an increase was detected only in the level of p62 mRNA but not in other mRNAs. Nevertheless, correlation analysis revealed a profound rearrangement of inter-gene correlations: only 30% of correlations found in the fatty streaks coincided with the correlations in normal fragments. Thus, new constellations were formed in fatty streaks concurrently with disappearance of correlations between mRNAs under study and mRNAs encoding factors of lipid accumulation, reverse cholesterol transfer, and some lipid sensors/transcription regulators of lipid metabolism.

[Variability of intima-media thickness of the common carotid arteries in Moscow city population without clinical symptoms of atherosclerosis].

AIM: To determine borderline values of intima-media thickness (IMT) of the common carotid arteries (CCA) in Moscow citizens without clinical symptoms of atherosclerosis. MATERIAL AND METHODS: A total of 885 (277 males and 608 females) Moscow citizens aged 20-79 years free of clinical symptoms of atherosclerosis participated in population-based epidemiological trial. CCA IMT was measured at ultrasonic scanning of the carotid arteries in high-resolution regimen. RESULTS: The trial provided data on variability of CCA IMT borderline values in different age groups of adult Moscow metaethnic population without clinical symptoms of atherosclerosis with gender reference. Quartile distribution of CCA IMT values enabled primary evaluation of predisposition of the population studied to atherosclerosis. CONCLUSION: This pilot study is the first to give Russian data on variability of population borderline values of CCA IMT obtained in the study of a representative sample. Russian data give additional material to European geographic gradiet CCA IMT and allow more accurate ultrasonographic identification of predisposition to atherosclerosis in persons with silent disease.