Association of mitochondrial mutations with the age of patients having atherosclerotic lesions

Variability of Mitochondrial DNA Heteroplasmy: Association with Asymptomatic Carotid Atherosclerosis

Background and Objectives: Atherosclerosis is one of the main reasons for cardiovascular disease development. This study aimed to analyze the association of mtDNA mutations and atherosclerotic plaques in carotid arteries of patients with atherosclerosis and conditionally healthy study participants from the Novosibirsk region. Methods: PCR fragments of DNA containing the regions of 10 investigated mtDNA mutations were pyrosequenced. The heteroplasmy levels of mtDNA mutations were analyzed using a quantitative method based on pyrosequencing technology developed by M. A. Sazonova and colleagues. Results: In the analysis of samples of patients with atherosclerotic plaques of the carotid arteries and conditionally healthy study participants from the Novosibirsk region, four proatherogenic mutations in the mitochondrial genome (m.5178C>A, m.652delG, m.12315G>A and m.3256C>T) and three antiatherogenic mutations in mtDNA (m.13513G>A, m.652insG, and m.14846G>A) were detected. A west-east gradient was found in the distribution of the mtDNA mutations m.5178C>A, m.3256C>T, m.652insG, and m.13513G>A. Conclusions: Therefore, four proatherogenic mutations in the mitochondrial genome (m.5178C>A, m.652delG, m.12315G>A, and m.3256C>T) and three antiatherogenic mutations in mtDNA (m.13513G>A, m.652insG, and m.14846G>A) were detected in patients with atherosclerotic plaques in their carotid arteries from the Novosibirsk region.

Mitochondrial Heteroplasmy as a Marker for Premature Coronary Artery Disease: Analysis of the Poly-C Tract of the Control Region Sequence

Mitochondrial DNA (mtDNA) differs from the nuclear genome in many aspects: a maternal inheritance pattern; being more prone to acquire somatic de novo mutations, accumulative with age; and the possible coexistence of different mtDNA alleles (heteroplasmy). Mitochondria are key cellular organelles responsible for energy production and involved in complex mechanisms, including atherosclerosis. In this scenario, we aimed to evaluate mtDNA variants that could be associated with premature cardiovascular disease. We evaluated 188 consecutive patients presenting with premature myocardial infarction with ST elevation (STEMI) confirmed by coronary angiogram. mtDNA polymorphisms and clinical data were evaluated and compared with 271 individuals from the same population (control group). Tobacco consumption (80.85% vs. 21.21%, p < 0.01) and dyslipidemia (38.83% vs. 28.41%, p = 0.02) were significantly more frequent among STEMI patients. Moreover, C16223T mtDNA mutation and poly-C heteroplasmy were significantly more frequent among premature STEMI male patients than in controls. The OR associated C16223T mtDNA with the increased presence of cardiovascular risk factors. Our data suggest that mtDNA 16223T and heteroplasmy may be associated with unstable premature atherosclerosis disease in men. Moreover, the presence of cardiovascular risk factors (CVRFs) was associated with C16223T mtDNA, with a cumulative effect. Protective mitochondrial pathways are potential therapeutic targets. Preventing exposure to the damaging mechanisms associated with CVRFs is of utmost importance.

Changes in histopathology and heteroplasmy rates over 8 years and effectiveness of taurine supplementation in a patient with mitochondrial nephropathy caused by MT-TL1 mutation: A case report

The m.3243A > G mutation in the mitochondrially encoded tRNA leucine 1 (MT-TL1) gene is known to cause mitochondrial nephropathy. However, its long-term effects of the m.3243A > G mutation on renal histopathology or heteroplasmy rates remain unknown. Here we present the case of a female patient who underwent renal biopsy at 34 years of age to investigate the reason for a low estimated glomerular filtration rate (eGFR) of 47.9 mL/min/1.73 m². Light microscopy revealed nephrosclerosis with granular swollen epithelial cells (GSECs) in the renal tubules. Genetic testing revealed the m.3243A > G mutation in the MT-TL1 gene. Over a follow-up period of 8 years, the eGFR declined at a rate of 1.50 mL/min/1.73 m²/year. A second renal biopsy was performed at the age of 42 years; the patient's glomerular sclerosis rate had increased from 45.5% to 63.2%, and the frequency of GSECs in the collecting ducts had increased from 5.8% to 20.8%. Furthermore, the heteroplasmy rate in blood cells and urinary sediment cells increased from 9% to 20% and 20% to 53%, respectively. Taurine therapy was initiated just after the second kidney biopsy. To date, after approximately 3 years of taurine administration, the rate of eGFR decline has markedly decreased to 0.26 mL/min/1.73 m²/year. This experience suggests that an increased heteroplasmy rate may be associated with the progression of mitochondrial nephropathy caused by MT-TL1 mutation. Furthermore, our case is the first to suggest the effectiveness of taurine for mitochondrial nephropathy caused by the m.3243A > G mutation in the MT-TL1 gene.

Mutations of mtDNA in some Vascular and Metabolic Diseases

BACKGROUND

The present review article considers some chronic diseases of vascular and metabolic genesis, the causes of which may be mitochondrial dysfunction. Very often, in the long course of the disease, complications may occur, leading to myocardial infarction or ischemic stroke and, as a result, death. In particular, a large percentage of human deaths nowadays belongs to cardiovascular diseases, such as coronary heart disease (CHD), arterial hypertension, cardiomyopathies, and type 2 diabetes mellitus.

OBJECTIVE

The aim of the present review was the analysis of literature sources, devoted to an investigation of a link of mitochondrial DNA mutations with chronic diseases of vascular and metabolic genesis.

RESULTS

The analysis of literature indicates the association of the mitochondrial genome mutations with coronary heart disease, type 2 diabetes mellitus, hypertension, and various types of cardiomyopathies.

CONCLUSION

The detected mutations can be used to analyze the predisposition to chronic diseases of vascular and metabolic genesis. They can also be used to create molecular-cell models necessary to evaluate the effectiveness of drugs developed for the treatment of these pathologies. MtDNA mutations associated with the absence of diseases of vascular and metabolic genesis could be potential candidates for gene therapy of the said diseases.

Some Molecular and Cellular Stress Mechanisms Associated with Neurodegenerative Diseases and Atherosclerosis

Chronic stress is a combination of nonspecific adaptive reactions of the body to the influence of various adverse stress factors which disrupt its homeostasis, and it is also a corresponding state of the organism's nervous system (or the body in general). We hypothesized that chronic stress may be one of the causes occurence of several molecular and cellular types of stress. We analyzed literary sources and considered most of these types of stress in our review article. We examined genes and mutations of nuclear and mitochondrial genomes and also molecular variants which lead to various types of stress. The end result of chronic stress can be metabolic disturbance in humans and animals, leading to accumulation of reactive oxygen species (ROS), oxidative stress, energy deficiency in cells (due to a decrease in ATP synthesis) and mitochondrial dysfunction. These changes can last for the lifetime and lead to severe pathologies, including neurodegenerative diseases and atherosclerosis. The analysis of literature allowed us to conclude that under the influence of chronic stress, metabolism in the human body can be disrupted, mutations of the mitochondrial and nuclear genome and dysfunction of cells and their compartments can occur. As a result of these processes, oxidative, genotoxic, and cellular stress can occur. Therefore, chronic stress can be one of the causes forthe occurrence and development of neurodegenerative diseases and atherosclerosis. In particular, chronic stress can play a large role in the occurrence and development of oxidative, genotoxic, and cellular types of stress.

The role of control region mitochondrial DNA mutations in cardiovascular disease: stroke and myocardial infarction

Recent studies associated certain type of cardiovascular disease (CVD) with specific mitochondrial DNA (mtDNA) defects, mainly driven by the central role of mitochondria in cellular metabolism. Considering the importance of the control region (CR) on the regulation of the mtDNA gene expression, the aim of the present study was to investigate the role of mtDNA CR mutations in two CVDs: stroke and myocardial infarction (MI). MtDNA CR mutations (both fixed and in heteroplasmy) were analysed in two demographically-matched case-control samples, using 154 stroke cases, 211 MI cases and their corresponding control individuals. Significant differences were found, reporting mutations m.16145 G > A and m.16311 T > C as potential genetic risk factors for stroke (conditional logistic regression: p = 0.038 and p = 0.018, respectively), whereas the m.72 T > C, m.73 A > G and m.16356 T > C mutations could act as possible beneficial genetic factors for MI (conditional logistic regression: p = 0.001, p = 0.009 and p = 0.016, respectively). Furthermore, our findings also showed a high percentage of point heteroplasmy in MI controls (logistic regression: p = 0.046; OR = 0.209, 95% CI [0.045-0.972]). These results demonstrate the possible role of mtDNA mutations in the CR on the pathogenesis of stroke and MI, and show the importance of including this regulatory region in genetic association studies.

Changes in Mitochondrial Genome Associated with Predisposition to Atherosclerosis and Related Disease

Atherosclerosis-related cardiovascular diseases remain the leading cause of morbidity and mortality, and the search for novel diagnostic and therapeutic methods is ongoing. Mitochondrial DNA (mtDNA) mutations associated with atherosclerosis represent one of the less explored aspects of the disease pathogenesis that may bring some interesting opportunities for establishing novel molecular markers and, possibly, new points of therapeutic intervention. Recent studies have identified a number of mtDNA mutations, for which the heteroplasmy level was positively or negatively associated with atherosclerosis, including the disease at its early, subclinical stages. In this review, we summarize the results of these studies, providing a list of human mtDNA mutations potentially involved in atherosclerosis. The molecular mechanisms underlying such involvement remain to be elucidated, although it is likely that some of them may be responsible for the increased oxidative stress, which plays an important role in atherosclerosis.

Data on association of mitochondrial heteroplasmy and cardiovascular risk factors: Comparison of samples from Russian and Mexican populations

Despite the fact that the role of mitochondrial genome mutations in a number of human diseases is widely studied, the effect of mitochondrial heteroplasmy in the development of cardiovascular disease has not been adequately investigated. In this study, we compared the heteroplasmy levels of mtDNA from leukocytes for m.3256C>T, m.3336T>C, m.12315G>A, m.5178C>A, m.13513G>A, m.14459G>A, m.14846G>A, m.15059G>A, m.652insG and m.1555A>G mutations in CVD-free subjects and CVD patients in samples derived from Russian and Mexican populations. It was demonstrated that heteroplasmy level of m.5178C>A was associated with CVD in Russian men, and m.14459G>A - in Russian women. Mitochondrial heteroplasmy level of m.13513G>A and m.652insG were associated with CVD in Mexican men, and only m.652insG- in Mexican women. The levels of heteroplasmy for mitochondrial mutations m.3336T>C, m.5178C>A, m.14459G>A, m.14846G>A and m.1555A>G were significantly higher in CVD-free Mexican men, and for m.3256C>T, m.3336T>C, and m.14459G>A - in CVD-free Mexican women.

The biological activity of high-density lipoprotein fractions and their role in the development of cardiovascular diseases

Increasing the human plasma concentration of high-density lipoproteins (HDL) may be part of strategy for control of cardiovascular diseases (CVD). HDL particles vary in their structure, metabolism, and biological activity. The review describes major HDL fractions (subpopulations) and discusses new findings on the antiatherogenic properties of HDL particles. The whole spectrum of HDL fractions, small, dense, protein-rich lipoproteins, has atheroprotective properties that are determined by the presence of specialized groups of proteins and lipids; however, this activity may be decreased in atherogenic lesion. Comprehensive structural and compositional analysis of HDL may provide key information to identify the fractions that have characteristic biological properties and lose their functionality in CVD. These fractions may be also biomarkers for the risk of CVD and hence represent pharmacological targets.

Analysis of mitochondrial DNA heteroplasmic mutations A1555G, C3256T, T3336C, С5178А, G12315A, G13513A, G14459A, G14846А and G15059A in CHD patients with the history of myocardial infarction

The present study was undertaken in order to advance our earlier studies directed to define genetic risk of atherosclerotic vascular lesion development on a base on the analysis of sets of mutational load relevant to the mitochondrial genome mutations. A comparative evaluation of the two study participants' populations (that included coronary heart disease (CHD) patients who underwent myocardial infarction and apparently healthy donors with no clinical manifestations of coronary heart disease) on heteroplasmy levels of nine mutations of the mitochondrial genome (A1555G, C3256T, T3336C, С5178А, G12315A, G13513A, G14459A, G14846А and G15059A) that were shown previously to be associated with risk factors for atherosclerosis was performed. Close associations with the risk of cardiovascular disease were confirmed for mutation C3256T (gene MT-TL1), G12315A (gene MT-TL2), G13513A (gene MT-ND5) and G15059A (gene MT-CYB) by RT-PCR.