Heat Shock Protein 90 as Therapeutic Target for CVDs and Heart Ageing

Cardiovascular diseases (CVDs) are the leading cause of death globally, representing approximately 32% of all deaths worldwide. Molecular chaperones are involved in heart protection against stresses and age-mediated accumulation of toxic misfolded proteins by regulation of the protein synthesis/degradation balance and refolding of misfolded proteins, thus supporting the high metabolic demand of the heart cells. Heat shock protein 90 (HSP90) is one of the main cardioprotective chaperones, represented by cytosolic HSP90a and HSP90b, mitochondrial TRAP1 and ER-localised Grp94 isoforms. Currently, the main way to study the functional role of HSPs is the application of HSP inhibitors, which could have a different way of action. In this review, we discussed the recently investigated role of HSP90 proteins in cardioprotection, atherosclerosis, CVDs development and the involvements of HSP90 clients in the activation of different molecular pathways and signalling mechanisms, related to heart ageing.

Teratogenic effect of alcohol on the myocardium of laboratory animals at the stages of prenatal ontogenesis (literature review)

Background. To date, close attention is paid to the problems of formation and development of the myocardium in general and in particular its structural components. This phenomenon is associated with an increase in cardiovascular malformations in both adults and infants. These defects can be caused by genetic factors, as well as various teratogenic substances. One such substance is alcohol. Despite the risks, many women still drink alcohol during pregnancy. The main problem is that almost half of pregnancies are unplanned, so a woman may continue to consume alcohol for several weeks before learning about her condition. Especially in young women, fertilization can occur in a state of intoxication. In addition, under the influence of ethanol, cardiac function may be impaired in the absence of structural abnormalities. Chronic alcohol intoxication causes changes in the myocardium at all levels of its structural organization. First of all, teratogenic changes caused by the action of ethanol affect the development of cardiomyocytes in the process of embryogenesis, which contributes to the underdevelopment of the structure or function of heart cells. Although the effect of maternal alcohol consumption on the fetus has been studied for decades, there are still conflicting conclusions about the severity of myocardial morphological changes depending on the time, frequency and duration of alcohol consumption. Objective: to conduct a retrospective analysis of literature sources devoted to the study of adverse effects on the fetus caused by alcohol. Methods. The paper conducted a retrospective analysis of literature references and formed an understanding of the changes in the structure of the myocardium caused by teratogenic effects of alcohol. Results and conclusion. Analysis of literature sources showed a high level of adverse effects observed in offspring born to alcoholic mothers. Detrimental effects of alcohol cause changes in the myocardium at all levels of structural organization, including its ultrastructure. It was studied that prenatal exposure to ethanol induces significant changes in relative heart weight, left ventricular wall thickness and cardiomyocyte size. Exposure to high concentrations of alcohol in experimental animals during gestation can lead to congenital heart defects, such as atrial, ventricular, and septal defects. The main manifestation of the prenatal effect of alcohol after birth is the fetal alcohol syndrome, which combines various degrees of deviation in the development of the child.

A Mathematical Model for Controlling Exchanged Spinor Waves between Hemoglobin, Tumor and T-Cells

To date, it is known that tumor cells respond to attacks of T-cells by producing some PD-1/PD-L1 and other connections. Unfortunately, medical methods for preventing these connections are expensive and sometimes non-effective. In this study, we suggest a new way for reducing these connections by producing some noise in the exchanged information between tumor cells, T-cells, hemoglobin, and controller cells such as those of the heart or brain. In this model, we assume that human cells use spinor waves for exchanging information because the velocity of exchanged information between two spinors, which are located a large distance apart, exceeds the velocity of light. In fact, two spinors could send and receive information from each other instantaneously. In this hypothesis, the DNAs within heart cells, brain cells or any controller are built from some spinors such as electrons, and by their motion, some waves are generated. These spinor waves are received by iron atoms and multi-gonal molecules within hemoglobin and other spinors within the blood vessels. The hemoglobin molecules are located on some blood cells, move along the blood vessels and pass on their information to cells, proteins and RNAs. The spins of the spinors within the hemoglobin and also the spins of the charges and ions within the blood vessels are entangled and could transmit any information between cells. Thus, when a tumor is formed, its spinor waves change, and are transmitted rapidly into the heart cells, brain cells and other controller cells. The heart, brain or other controller cells diagnose these quantum waves, and by using the entanglement between the spinors within the blood vessels and the hemoglobin, send some messages to the T-cells. These messages are received by tumor cells and they become ready to respond to attacks. To prevent the reception of information by tumor cells, we can make use of some extra cells or hemoglobin, which interact with spinors and hemoglobin around tumor cells and produce some noise. Science quantum spinor waves are minute and have minor power and intensity; we cannot detect them by our present electronic devices and for this reason, we suggest using biological cells. This is a hypothesis; however, if experiments show its validity, some types of cancers could be cured or controlled by this method. We formulate the model by considering quantum entanglement between spinors within biological systems. By changing any spin within this system, all spins change and consequently, information is transmitted immediately. Then, we add new spinors to this system mathematically, and show that this causes the correlations between the initial spinors to reduce. Thus, the spinors of the extra hemoglobin or cells could act like noise, and prevent reception of real information by tumor cells.

The Trypanosoma cruzi kinetoplast DNA minicircle sequences transfer biomarker of the multidrug treatment of Chagas disease

Background: The Trypanosoma cruzi infection renders the transfer of the mitochondrion kinetoplast DNA minicircle sequences into the host’s genome. The Aves are refractory to the infection, but chicks hatched from the T. cruzi inoculated eggs integrate the DNA minicircle sequences into the germ line cells. Rabbits, mice and chickens with the minicircle sequences mutations develop the Chagas cardiomyopathy and the DNA transfer underpins the heart disease. Methodology: The PCR with the specific primer sets revealed the Protist nuclear DNA and the kinetoplast DNA in the agarose gels bands probed with the radiolabel specific sequences from tissues of the T. cruzi-infected rabbits and of the mice. A targetprimer TAIL-PCR amplification employing primer sets from the chickens, rabbits and mice, in combination with primer sets from the the T. cruzi kinetoplast minicircle sequences was used. This approach led us to disclose the integration sites of the kinetoplast DNA biomarker, then, used to monitor the effect of multidrug treatment of the T. cruzi infected mice. Principal findings: The Southern hybridization, clone and sequence of the amplification products revealed the DNA minicircle sequences integrations sites in the LINE transposable elements. An array of inhibitors of eukaryote cells division was used to arrest the DNA transfer. It was shown that nine out of 12 inhibitors prevented the kinetoplast DNA integration into the macrophage genome. The multidrug treatment of the acutely T. cruzi-infected mice with Benznidazole, Azidothymidine and Ofloxacin lessened circa 2.5-fold the rate of the minicircle sequences integrations in the mouse genome and inhibited the rejection of the target heart cells. Conclusion and significance: The T. cruzi mitochondrion kinetoplast minicircle sequences transfer driven pathogenesis of Chagas disease is an ancient Cross-Kingdom DNA phenomenon of evolution and, therefore, paradigm research with effective purposing inhibitors is needed.

Therapeutic Applications of Extracellular Vesicles for Myocardial Repair

Cardiovascular disease is the leading cause of human death worldwide. Drug thrombolysis, percutaneous coronary intervention, coronary artery bypass grafting and other methods are used to restore blood perfusion for coronary artery stenosis and blockage. The treatments listed prolong lifespan, however, rate of mortality ultimately remains the same. This is due to the irreversible damage sustained by myocardium, in which millions of heart cells are lost during myocardial infarction. The lack of pragmatic methods of myocardial restoration remains the greatest challenge for effective treatment. Exosomes are small extracellular vesicles (EVs) actively secreted by all cell types that act as effective transmitters of biological signals which contribute to both reparative and pathological processes within the heart. Exosomes have become the focus of many researchers as a novel drug delivery system due to the advantages of low toxicity, little immunogenicity and good permeability. In this review, we discuss the progress and challenges of EVs in myocardial repair, and review the recent development of extracellular vesicle-loading systems based on their unique nanostructures and physiological functions, as well as the application of engineering modifications in the diagnosis and treatment of myocardial repair.

755 Rat engineered heart tissue is a novel in vitro model to evaluate cardiomyocyte proliferation and fibroblast activation after injury

Aims Adult mammals, including humans, fail to regenerate the majority of the lost cardiomyocytes (CMs) that are replaced with scar tissue after injury. This lack of regenerative response is due to the loss of proliferative capacity of adult CMs which in mice occurs 7 days after birth. An in vitro model that recapitulates these changes has not been developed yet. Using rat engineered heart tissues (rEHTs) we have developed a custom-made cryoinjury system to test the hypothesis that maturation of CMs in EHTs regulates the proliferative response of CMs after injury. Methods rEHT were generated using neonatal rat heart cells. A discrete lesion was produced on the mid-section of mature (Day 18) and immature (Day 6) EHTs using a custom-made system based on liquid nitrogen and a 23G needle and medium was supplemented with EdU for 48 h. Results Cryoinjury in mature EHTs produces a localized injury, preserving their residual contractile activity that does not recover over time. We observed a significant increase of EdU+CMs post injury (6.3 ± 1.9% vs. 10.1 ± 1.6%) without significant changes in Ki67+ and pH3+ CMs suggesting that cryoinjury in mature rEHTs induces DNA synthesis but not CM proliferation. Injury in mature EHTs induced also significant proliferation and activation of fibroblasts with collagen deposition. Interestingly, cryoinjury performed in immature EHTs stimulated a significant proliferative response in CMs Conclusions Similar to adult rodents, we show that cryoinjury induces DNA synthesis in CMs without proliferative response and contractile recovery. On the other hand, cryoinjury in immature EHTs leads to CMs proliferation. Moreover, mature EHT fibroblast response to injury retraces the activation progression of cardiac fibroblast after infarction characterized by proliferation, increase of activation markers, increase of collagen deposition suggesting EHTs as a novel model to investigate the biology of cardiac regeneration upon injury.

Ethyl Pyruvate Ameliorates Experimental Autoimmune Myocarditis

Ethyl pyruvate (EP) has profound anti-inflammatory and immunomodulatory properties. Here, its effects were determined on experimental autoimmune myocarditis (EAM) induced in mice by heart-specific myosin-alpha heavy chain peptide immunization. EP was applied intraperitoneally, daily, starting with the immunization. Severity of EAM was determined by histological assessment of immune cell infiltrates into the heart. Cells were phenotypically characterized by flow cytometry. Concentration of cytokines in cell culture supernatants and sera was determined by ELISA. EP reduced the infiltration of immune cells into the heart and lessened heart inflammation. Smaller number of total immune cells, as well as of CD11b+ and CD11c+ cells were isolated from the hearts of EP-treated mice. A reduced number of antigen-presenting cells, detected by anti-CD11c, MHC class II and CD86 antibodies, as well as of T helper (Th)1 and Th17 cells, detected by anti-CD4, IFN-γ and IL-17 antibodies, was determined in mediastinal lymph nodes draining the heart, in parallel. In the spleen, only the number of CD11c+ cells were reduced, but not of the other examined populations, thus implying limited systemic effect of EP. Reduced production of IFN-γ and IL-17 by myosin-alpha heavy chain peptide-restimulated cells of the lymph nodes draining the site of immunization was observed in EP-treated mice. Our results clearly imply that EP restrains autoimmunity in EAM. Therapeutic application of EP in the treatment of myocarditis in humans should be addressed in the forthcoming studies.

Arrhythmogenesis in heart cells involves reverse E–C coupling and reverse electrotonic conduction along T-tubules

Early afterdepolarization (EAD) is an aberrant cardiac afterpotential that underlies the development of life-threatening ventricular arrhythmias. It is believed that the development of EAD is caused by the reactivation of L-type Ca2+ current during the period of the action potential plateau; however, the cellular mechanisms that underlie the development of EAD is still controversial. One favorable alternative is the depolarizing reverse-mode operation of the Na+/Ca2+ exchanger, which is activated by aberrant Ca2+ release from the sarcoplasmic reticulum in the process of reverse E–C coupling. Since EADs develop preferentially in damaged heart cells with abnormal Ca2+-signaling, here I studied the causal link between the development of EADs and aberrant intracellular Ca2+ level ([Ca2+]i) dynamics in mouse heart cells using the whole-cell clamp technique. My results show (1) the generation of EADs was preceded by the development of depolarizing membrane potential (Vm) fluctuation, (2) the depolarizing Vm fluctuation is associated with [Ca2+]i elevation, suggesting an involvement of reverse E–C coupling via the Na+/Ca2+ exchanger, and (3) that extending the T-tubules’ length constant by decreasing the extracellular K+ level facilitated the development of the Vm fluctuation and EADs. Taken together, I conclude that EADs are caused by the depolarizing Vm fluctuation, which is induced locally in the T-tubule membrane by aberrant [Ca2+]i elevation and is conducted back electrotonically along the T-tubules.

Functional state of cardiomyocyte mitochondria in malignant process in presence of comorbid pathology in experiment

Purpose of the study. An analysis of indices of free radical oxidation and respiration of mitochondria of heart cells in a malignant process in presence of diabetes mellitus and chronic neurogenic pain in experimental animals.Materials and methods. The study included outbred female rats (n=32) and С57ВL/6 female mice (n=84). Experimental groups of rats were: intact group 1 (n=8), control group 1 (n=8) with diabetes mellitus (DM), comparison group 1 (n=8) with standard subcutaneous transplantation of Guerin’s carcinoma, main group 1 (n=8) with Guerin’s carcinoma transplanted after 1 week of persistent hyperglycemia. Experimental groups of mice were: intact group 2 (n=21), control group 2 (n=21) with a model of chronic neurogenic pain (CNP), comparison group 2 (n=21) with standard subcutaneous transplantation of melanoma (B16/F10), main group 2 (n=21) (CNP+B16/F10) with melanoma transplanted 3 weeks after the CNP model creation. Heart mitochondria were isolated by differential centrifugation. Levels of cytochrome C (ng/mg of protein), 8-hydroxy-2'-deoxyguanosine (8-OHdG) (ng/mg of protein), and malondialdehyde (MDA) (μmol/g of protein) were measured in mitochondrial samples by ELISA. Statistical analysis was performed using the Statistica 10.0 program.Results. DM in rats upregulated 8-OHdG by 6.3 times and MDA by 1.9 times (р=0.0000) and downregulated cytochrome C by 1.5 times (р=0.0053) in heart cell mitochondria, compared to intact values. DM+Guerin’s carcinoma in rats increased 8-OHdG by 14.0 times and MDA by 1.7 times (р=0.0000) and decreased cytochrome C by 1.5 times (р=0.0000), compared to intact values. CNP in mice did not affect the studied parameters in mitochondria of the heart. CNP+B16/F10 in mice increased 8-OHdG by 7.1 times and MDA by 1.6 times (р=0.0000) and decreased cytochrome C by 1.6 times (р=0.0008).Conclusions. Comorbidity (diabetes mellitus, chronic neurogenic pain) together with malignant pathology aggravates mitochondrial dysfunction of heart cells with destabilization of the respiratory chain mediated by free radical oxidation processes.