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  • 1
    In: Nucleic Acids Research, Oxford University Press (OUP), Vol. 50, No. 18 ( 2022-10-14), p. 10264-10277
    Abstract: The mutational spectrum of the mitochondrial DNA (mtDNA) does not resemble any of the known mutational signatures of the nuclear genome and variation in mtDNA mutational spectra between different organisms is still incomprehensible. Since mitochondria are responsible for aerobic respiration, it is expected that mtDNA mutational spectrum is affected by oxidative damage. Assuming that oxidative damage increases with age, we analyse mtDNA mutagenesis of different species in regards to their generation length. Analysing, (i) dozens of thousands of somatic mtDNA mutations in samples of different ages (ii) 70053 polymorphic synonymous mtDNA substitutions reconstructed in 424 mammalian species with different generation lengths and (iii) synonymous nucleotide content of 650 complete mitochondrial genomes of mammalian species we observed that the frequency of AH  & gt; GH substitutions (H: heavy strand notation) is twice bigger in species with high versus low generation length making their mtDNA more AH poor and GH rich. Considering that AH  & gt; GH substitutions are also sensitive to the time spent single-stranded (TSSS) during asynchronous mtDNA replication we demonstrated that AH  & gt; GH substitution rate is a function of both species-specific generation length and position-specific TSSS. We propose that AH  & gt; GH is a mitochondria-specific signature of oxidative damage associated with both aging and TSSS.
    Type of Medium: Online Resource
    ISSN: 0305-1048 , 1362-4962
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    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
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  • 2
    In: BMC Biology, Springer Science and Business Media LLC, Vol. 21, No. 1 ( 2023-05-08)
    Abstract: Aging in postmitotic tissues is associated with clonal expansion of somatic mitochondrial deletions, the origin of which is not well understood. Such deletions are often flanked by direct nucleotide repeats, but this alone does not fully explain their distribution. Here, we hypothesized that the close proximity of direct repeats on single-stranded mitochondrial DNA (mtDNA) might play a role in the formation of deletions. Results By analyzing human mtDNA deletions in the major arc of mtDNA, which is single-stranded during replication and is characterized by a high number of deletions, we found a non-uniform distribution with a “hot spot” where one deletion breakpoint occurred within the region of 6–9 kb and another within 13–16 kb of the mtDNA. This distribution was not explained by the presence of direct repeats, suggesting that other factors, such as the spatial proximity of these two regions, can be the cause. In silico analyses revealed that the single-stranded major arc may be organized as a large-scale hairpin-like loop with a center close to 11 kb and contacting regions between 6–9 kb and 13–16 kb, which would explain the high deletion activity in this contact zone. The direct repeats located within the contact zone, such as the well-known common repeat with a first arm at 8470–8482 bp (base pair) and a second arm at 13,447–13,459 bp, are three times more likely to cause deletions compared to direct repeats located outside of the contact zone. A comparison of age- and disease-associated deletions demonstrated that the contact zone plays a crucial role in explaining the age-associated deletions, emphasizing its importance in the rate of healthy aging. Conclusions Overall, we provide topological insights into the mechanism of age-associated deletion formation in human mtDNA, which could be used to predict somatic deletion burden and maximum lifespan in different human haplogroups and mammalian species.
    Type of Medium: Online Resource
    ISSN: 1741-7007
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
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  • 3
    In: Journal of Ural Medical Academic Science, Bulletin of the Ural Medical Academie Science, Vol. 19, No. 3 ( 2022), p. 322-332
    Abstract: The article substantiates the algorithm and methodology of the study aimed at search and analysis of the determinants of somatic mitochondrial heteroplasmy in the elderly people. Aging is considered as a process that has developed in the process of evolution, characterized by a decrease in all basic biological functions and accompanied by a gradual degradation of organs, tissues and systems of the body, a classification of the main hypotheses and theories of aging is given. The need to develop diagnostic criteria and markers to differentiate the concept of «healthy aging» from diseases of the elderly is noted. Separately, the authors analyze the role of mitochondria in the development of age-related changes associated with the development of neurodegeneration and muscular dystrophy. It has been noted that the development of senile changes is to some extent associated with the main function of mitochondria, namely the oxidation of nutrients and the production of ATP molecules, a universal energy source for most biological processes in cells. For the mitochondrial genome, a driving mechanism has been proposed to explain how mitochondrial somatic mutations can lead to certain aging phenotypes — neurodegeneration and muscular dystrophy. To establish the relationship between mitochondrial somatic deletions and age-related changes, an algorithm and methodology have been developed based on a comprehensive study of the determinants of somatic mitochondrial heteroplasmy in a cohort of elderly people. It is planned to analyze the dynamics of mitochondrial somatic mutations in muscle tissues (biopsies) for 450 elderly volunteers. The authors propose an original approach to the determination of mtDNA heteroplasmy and the detection of de-novo mutations, including the enrichment of mitochondrial fractions and the purification of mtDNA from muscle tissues, as well as a method for quantifying mtDNA copy number to normalize the amount of genomic material in the samples. The resulting material will be used to prepare libraries for sequencing on NGS platforms. Subsequently, the data after bioinformatic analysis will be compared with the results of neurological and psychological studies, including an assessment of the level of cognitive processes, the presence of asthenic disorders, and an assessment of the patient’s rehabilitation potential. It is assumed that this psychoneurological block will allow us to further distinguish at least three groups among volunteers, namely: persons with normal aging (healthy aging), patients with a weakening of mental and physical abilities associated with neurodegenerative or with vascular pathologies. In order to search for informative markers in the immune system that allow differentiating «healthy aging» from diseases of the elderly, it is proposed to perform a correlation analysis between the assessment of immune and cytokine status and the data of clinical and bioinformatic studies.
    Type of Medium: Online Resource
    ISSN: 2073-9125 , 2500-0918
    Language: Unknown
    Publisher: Bulletin of the Ural Medical Academie Science
    Publication Date: 2022
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  • 4
    In: Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 144, No. 23 ( 2021-12-07), p. 1845-1855
    Abstract: Despite advances in surgery and pharmacotherapy, there remains significant residual ischemic risk after coronary artery bypass grafting surgery. Methods: In REDUCE-IT (Reduction of Cardiovascular Events With Icosapent Ethyl–Intervention Trial), a multicenter, placebo-controlled, double-blind trial, statin-treated patients with controlled low-density lipoprotein cholesterol and mild to moderate hypertriglyceridemia were randomized to 4 g daily of icosapent ethyl or placebo. They experienced a 25% reduction in risk of a primary efficacy end point (composite of cardiovascular death, myocardial infarction, stroke, coronary revascularization, or hospitalization for unstable angina) and a 26% reduction in risk of a key secondary efficacy end point (composite of cardiovascular death, myocardial infarction, or stroke) when compared with placebo. The current analysis reports on the subgroup of patients from the trial with a history of coronary artery bypass grafting. Results: Of the 8179 patients randomized in REDUCE-IT, a total of 1837 (22.5%) had a history of coronary artery bypass grafting, with 897 patients randomized to icosapent ethyl and 940 to placebo. Baseline characteristics were similar between treatment groups. Randomization to icosapent ethyl was associated with a significant reduction in the primary end point (hazard ratio [HR], 0.76 [95% CI, 0.63–0.92] ; P =0.004), in the key secondary end point (HR, 0.69 [95% CI, 0.56–0.87]; P =0.001), and in total (first plus subsequent or recurrent) ischemic events (rate ratio, 0.64 [95% CI, 0.50–0.81]; P =0.0002) compared with placebo. This yielded an absolute risk reduction of 6.2% (95% CI, 2.3%–10.2%) in first events, with a number needed to treat of 16 (95% CI, 10–44) during a median follow-up time of 4.8 years. Safety findings were similar to the overall study: beyond an increased rate of atrial fibrillation/flutter requiring hospitalization for at least 24 hours (5.0% vs 3.1%; P =0.03) and a nonsignificant increase in bleeding, occurrences of adverse events were comparable between groups. Conclusions: In REDUCE-IT patients with a history of coronary artery bypass grafting, treatment with icosapent ethyl was associated with significant reductions in first and recurrent ischemic events. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01492361.
    Type of Medium: Online Resource
    ISSN: 0009-7322 , 1524-4539
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2021
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  • 5
    In: Blood, American Society of Hematology, Vol. 126, No. 23 ( 2015-12-03), p. 5238-5238
    Abstract: Introduction The majority of clinical recommendations on MDS indicate the use of IST for low-risk hypoplastic MDS patients. ATG followed by cyclosporine A (CSA) is recommended for younger pts with normal karyotype or with +8, CSA - for older patients with autoimmune phenomenon or hypoplastic bone marrow. There are no reports on the use of CSA with splenectomy as a combined IST for MDS patients. Here we report the long term (20 years) results of the single center trial comprising 61 MDS pts treated with CSA as the first or the second line treatment + splenectomy. Patients and methods. Since 1995 till June 2015, 61 patients were included in the combined IST protocol. There were 34 males, 27 females; median age constituted 39 years (16-74), refractory cytopenias with multileaneage dysplasia = 46, RAEB1/2 = 15; IPSS - low-risk= 4, intermediate 1 =40, intermediate-2 =9, high =4; no risk evaluation - 4 patients. All patients had trepanobiopsy evaluation, half of them - bilateral. It worth to note that bilateral trepanobiopsy permitted to redefine cellularity in 15% of patients. Pure hypoplastic forms of MDS were registered in 38 patients (63%), combination of hypoplasia with hyperplasia or normal cellularity - in 10 (16%), hyperplastic forms - in 13 (21%); non-clonal lymphoid nodules in b/m were detected in 29 pts (46%); fibrosis - in 7. Cytogenetics was done in 57 pts, 32 had normal karyotype; 5 had trisomy 8; 8 - high risk cytogenetics (-7/7q-, complex); 8 - different intermediate. Cyclosporine A was applied at a dose 5 mg/kg per day, followed by reevaluation of response at 2-3 months. In case of response CSA was continued, if there was no response or it was inadequate - splenectomy was done followed again by CSA; if progression occurred - CSA was stopped. We consider splenectomy as a component of the programmed IST as it leads to removement of a big lymphoid organ. For younger patients ATG for 20 mg/kg for 5 days could become the 2nd or the 3rd line of treatment. For patients with sibling donors allogeneic HSCT was an option. Analysis was carried out in June 2015. The patients were grouped for analysis according to cellularity (hypo vs hyper, in case of combination hypo with hyper/normal the case was considered as hypocellular), % of b/m blast cells ( 〈 〉 5%), IPSS index (low/int-1 vs int-2/high), cytogenetics, the presence of lymphoid nodules. Results. CSA was started as the 1st line treatment in 42 patients, as the second line (after ATG or splenectomy or ESA) - in 20. 5 patients were transplanted from sibling donors. 35 patients received CSA as monotherapy (16 of them had a progression or a transformation to AML). Totally splenectomy was performed in 20 patients, in 8 patients it was followed by additional immunosuppression with ATG (9 patients) or MMF (1 patient). Splenectomy was performed by laparoscopy, no deaths or sever complications were noted. Half of the splenectomized patients achieved sustained response after operation and continuation of CSA. On the whole 18 patients had progression to RAEB or transformation to AML (1 from low-risk group, 7 - int1, 6 - int2, 5 - from high risk). Complete remission was achieved in 15 patients (24%), with overall response rate of 56% (n=34) with a median duration of response - 21 months (1-230 mo). The 20-years survival data revealed highly statistical difference between hypoplastic forms of MDS vs hyperplastic (38% vs 0%), bone marrow blast cells less vs more than 5% (43% vs 5%), IPSS categories low/int1 vs int2/high (50% vs 0%), cytogenetics favorable vs intermediate vs high (62% vs 35% vs 0%) (Pic.1). No differences were detected in patients with or without lymphoid nodules in b/m (38% vs 35%). Conclusions Our small but prolonged study has demonstrated a substantial long-term efficacy of the combined IST. CSA followed by splenectomy is a reasonable treatment approach in MDS patients with hypoplastic features in bone marrow, normal or intermediate karyotype, low blast cell count, low/int1 IPSS score. Pic.1 Overall survival of MDS patients treated with combined IST depending on cellularity, blast cells count, cytogenetic features and IPSS score. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2015
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  • 6
    Online Resource
    Online Resource
    American Society of Hematology ; 2010
    In:  Blood Vol. 116, No. 21 ( 2010-11-19), p. 1879-1879
    In: Blood, American Society of Hematology, Vol. 116, No. 21 ( 2010-11-19), p. 1879-1879
    Abstract: Abstract 1879 Splenectomy in patients with MDS is a treatment option that is beeing applied very rare [Steensma D., et al, Leuk Res.,2003; Bourgeosis E., et al, Leukemia, 2001]. There are anecdotal reports with very few patients demonstrating its efficacy. In most cases splenectomy was indicated for MDS patients with immune related thrombocytopenia. Here we would like to report the results of 33 splenectomies in patients with MDS who have been treated in our Center during 1994–2010. Within this period of follow-up totally 155 patients were diagnosed with different forms of MDS, 35% of them presenting with hypoplasia. The MDS treatment algorithm in our Center incorporates splenectomy as one of the options for pts with hypoplastic forms of MDS with bone marrow blast count less than 10%, refractory to initial cyclosporin A treatment or refractory to transfusions. Among patients who were splenectomised there were 20 females, 13 males with a median age of 40 years (range 18–74). Median time from diagnosis to splenectomy was 12 months (range 4–107). By WHO-classification there were 2 patients with RA, 22 – with RCMD, 2 – with MDS and del (5q), 6 - with RAEB, 1 - with AML after MDS. Cytogenetic analysis was available in 32 cases, and karyotype was normal in 15 patients (47%).The most common abnormalities were: del (5q) - 3, del (20q) - 2, trisomy 8 - 2, tetrasomy 8 - 1, monosomy 7 - 2, complex karyotype - 4. Bone marrow biopsy revealed hypoplasia in 25 patients (75%), myelofibrosis – in 7 (21%). The median WBC count was 2,6*109/L (range 0,6-8,7), hemoglobin 6,9 g/dL (47-119) and platelets 26*109/L (6-170). 27 pts (82%) were RBC transfusion dependent, 22 (67%) - platelets transfusion dependent. 13 pts had received immunosuppression therapy (ATG, cyclosporine A) before splenectomy, 2 - cytotoxic chemotherapy, 3 - decitabine. The majority of splenectomies were done by laparoscopic method - 26 (79%), in one case the convertion was done. In all cases we performed liver biopsy. Postoperative complications (hemorrhage) occurred in 1 patient but there were no deaths due to operation. One death occurred in 7 days after splenectomy due to fulminant progression to AML. Median spleen weight was 180 gms (range 70–930). Median intraoperative blood loss was 250 ml (range 50–9350). Histology was available in 30 patients. Extramedullary hematopoesis was revealed in 3 cases (10%), blast infiltration - in 2 (7%), massive lymphoid infiltration was detected in 5 cases and in one patient in was proved to be clonal (marginal zone lymphoma, MZL). Hemosiderin depositions in the macrophages were seen in half of the cases -16 (53%). One case was characterized by granulomatosis in spleen and liver with negative immunohistohemical staining to Mycobacteria tuberculosis. Splenectomy lead to sustained improvement of cytopenias in 16 cases (48%): decreased transfusion dependence in 14 (42%) and transfusion independence in 2 (6%). After splenectomy 5 patients were followed by “wait and see” approach, 17 continued with immunosuppressive therapy (ATG,CyA), 3 patients were treated with cytotoxic chemotherapy, 1 – with decytabine, 2 received EPO, 1- danazol, 2 - iron chelation therapy, 2 – only transfusions therapy. We did not noticed the infections rate augmentation after splenectomy. Transformation to AML was registered 6 (18%) at median 6 months (0,3 -9). 13 splenectomized patients (39%) died at a median 12 months (range 0,3-84) and the main death reasons were: AML progression, aplasia deterioration followed by infections and hemorrhage. 20 patients are alive with a median follow-up after splenectomy 33 months (2-108). Analysis of our 15-years study data give us a confidence to conclude that splenectomy still may be an adequate option for distinct forms of MDS (hypoplastic forms with bone marrow blast count less than 10%, refractory to initial immunosupressive treatment or refractory to transfusions), producing cytopenia improvement in half of the patients with decreasing transfusion dependance also in half of the patients, sometimes bringing a clear diagnosis (MZL). The mechanism of action is not very clear but we can speculate that splenectomy removes the “cell-destroying” organ, deminishes immune pathways of cytopenias due to large lymphoid compartment deletion, provides the resustainment of sensitivity to immunosupressive agents. Disclosures: No relevant conflicts of interest to declare.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
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    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2010
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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  • 7
    In: Cytometry Part B: Clinical Cytometry, Wiley, Vol. 100, No. 3 ( 2021-05), p. 312-321
    Abstract: Myelodysplastic syndromes (MDS) can present a challenge for clinicians. Multicolor flow cytometry (MFC) can aid in establishing a diagnosis. The aim of this study was to determine the optimal MFC approach for MDS. Methods The study included 102 MDS (39 low‐grade MDS), 83 cytopenic patients without myeloid neoplastic disorders (control group), and 35 healthy donors. Bone marrow was analyzed using a six‐color MFC. Analysis was conducted according to the “Ogata score,” “Wells score,” and the integrated flow cytometry (iFC) score. Results The respective sensitivity and specificity values were 77.5% and 90.4% for the Ogata score, 79.4% and 81.9% for the Wells score, and 87.3% and 87.6% for the iFC score. Specificity was not 100% due to deviations of MFC parameters in the control group. Patients with paroxysmal nocturnal hemoglobinuria (PNH) had higher levels of CD34 + CD7 + myeloid cells than donors. Aplastic anemia and PNH were characterized by a high proportion of CD56 + cells among CD34 + precursors and neutrophils. The proportion of MDS‐related features increased with the progression of MDS. The highest number of CD34 + blasts was found in MDS with excess blasts. MDS with isolated del(5q) was characterized by a high proportion of CD34 + CD7 + cells and low granularity of neutrophils. In 39 low‐grade MDS, the sensitivities were 53.8%, 61.5%, and 71.8% for Ogata score, Wells score, and iFC, respectively. Conclusion The results support iFC as a useful diagnostic tool in MDS.
    Type of Medium: Online Resource
    ISSN: 1552-4949 , 1552-4957
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2180651-2
    SSG: 12
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