226 research outputs found

    Cardiac miRNA expression during the development of chronic anthracycline-induced cardiomyopathy using an experimental rabbit model

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    Background: Anthracycline cardiotoxicity is a well-known complication of cancer treatment, and miRNAs have emerged as a key driver in the pathogenesis of cardiovascular diseases. This study aimed to investigate the expression of miRNAs in the myocardium in early and late stages of chronic anthracycline induced cardiotoxicity to determine whether this expression is associated with the severity of cardiac damage.Method: Cardiotoxicity was induced in rabbits via daunorubicin administration (daunorubicin, 3 mg/kg/week; for five and 10 weeks), while the control group received saline solution. Myocardial miRNA expression was first screened using TaqMan Advanced miRNA microfluidic card assays, after which 32 miRNAs were selected for targeted analysis using qRT-PCR.Results: The first subclinical signs of cardiotoxicity (significant increase in plasma cardiac troponin T) were observed after 5 weeks of daunorubicin treatment. At this time point, 10 miRNAs (including members of the miRNA-34 and 21 families) showed significant upregulation relative to the control group, with the most intense change observed for miRNA-1298-5p (29-fold change, p < 0.01). After 10 weeks of daunorubicin treatment, when a further rise in cTnT was accompanied by significant left ventricle systolic dysfunction, only miR-504-5p was significantly (p < 0.01) downregulated, whereas 10 miRNAs were significantly upregulated relative to the control group; at this time-point, the most intense change was observed for miR-34a-5p (76-fold change). Strong correlations were found between the expression of multiple miRNAs (including miR-34 and mir-21 family and miR-1298-5p) and quantitative indices of toxic damage in both the early and late phases of cardiotoxicity development. Furthermore, plasma levels of miR-34a-5p were strongly correlated with the myocardial expression of this miRNA.Conclusion: To the best of our knowledge, this is the first study that describes alterations in miRNA expression in the myocardium during the transition from subclinical, ANT-induced cardiotoxicity to an overt cardiotoxic phenotype; we also revealed how these changes in miRNA expression are strongly correlated with quantitative markers of cardiotoxicity

    Cardiovascular toxicity from therapies for light chain amyloidosis

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    : Amyloid light-chain (AL) amyloidosis is a hematological disorder characterized by abnormal proliferation of a plasma cell clone producing monoclonal free light chains that misfold and aggregate into insoluble fibrils in various tissues. Cardiac involvement is a common feature leading to restrictive cardiomyopathy and poor prognosis. Current first-line treatments aim at achieving hematological response by targeting the plasma cell clones, and these have been adapted from multiple myeloma therapy. Patients with AL amyloidosis often exhibit multiorgan involvement, making them susceptible to cancer therapy-related cardiovascular toxicity. Managing AL amyloidosis is a complex issue that requires enhanced knowledge of the cardio-oncological implications of hematological treatments. Future research should focus on implementing and validating primary and secondary prevention strategies and understanding the biochemical basis of oncological therapy-related damage to mitigate cardiovascular toxicity

    Лабораторний моніторинг і нутритивно-метаболічна підтримка процесу підготовки спортсменів

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    Монографію присвячено питанням стимуляції фізичної та психічної працездатності в динаміці процесу підготовки спортсменів з урахуванням принципів і методологій клінічної медицини на основі обʼєктивних даних лабораторного контролю. Наведено інформацію стосовно інформативності найбільш популярних тестів, використовуваних для оцінювання впливу фізичних навантажень на показники гомеостазу організму спортсменів. Проаналізовано фактори, що впливають на якість лабораторної діагностики та вміст / активність окремих показників периферичної крові спортсменів. Значну частину монографії присвячено опису та систематизації даних щодо обґрунтованого використання широкої палітри спеціальних харчових добавок з урахуванням Положень Консенсусу МОК щодо застосування спортсменами сучасних нутритивно-метаболічних засобів і незаборонених фармакологічних засобів

    Development and characterization of pore-blocking small molecules against cholesterol-dependent cytolysins as anti-virulence strategy

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    Cholesterol-dependent cytolysins (CDC) are acknowledged virulence factors of a wide range of pathogenic gram-positive bacteria like Streptococci, Clostridia, and Listeria etc. CDC selectively target membranes that contain cholesterol and induce pathogenesis in the host organisms by versatile mechanisms. Bacteria release CDC during an infection, which infuriate the infection and the treatment of infection becomes challenging with the contemporary regime of anti-infectives. The noxious responses of CDC include direct toxicity via pore formation, manipulation of cellular signaling to promote bacterial survival and evasion of the immune system. Worldwide, millions of deaths are associated with CDC like PLY, PFO, LLO etc. Therefore, CDC have been considered as a potential target for drugs. In the research of the last few decades, multiple natural and synthetic small molecules have been proposed as anti-toxins, however, due to lack of specificity, none of them were contemplated for clinical testing. Thus, to date there is no specific treatment available to counter CDC manifestations and the goal of this project is to develop and validate specific small molecules against CDC. PLY was selected as a prototype CDC for testing of small molecules. In our earlier work, a model of PLY-pore was developed to virtually screen half a million molecules from online databases that could block the oligomerization and ultimately pore formation of PLY. Pore-Blocker-1 (PB-1), was the only molecule that actively inhibited PLY in a hemolysis assay and, thereon, its optimization led to the discovery of PB-2 with ten times improved activity. In this dissertation, PB-1 and 2 were validated in the BLI assay. Cryo-TEM analysis showcased that PB-2 prevented the PLY penetration in membranes of cholesterol-liposomes. By analyzing several closely related derivatives of PB-2 the pharmacophore of inhibitors was identified, which enabled the effective alteration of scaffolds to produce PB-3, a more chemically stable and potent inhibitor of PLY. PB-3 exhibited an IC50 of 3 µM in the hemolysis assay and a KD value of 256 nM against PLY in the BLI assay. Analogous potency of PB-3 was observed in the LDH assay and cellular microscopy. PB-3 was generated and quantified through the protein-catalyzed ligation of precursor fragments. The actual mechanism of inhibitors was unveiled by evaluating the activity of inhibitors against multiple PLY-mutants and in contrast to the virtually proposed mechanism of binding, a cysteine mutant of PLY suggested that PB-3 might be binding to a cysteine in the membrane-binding domain of PLY. Then, BLI and MS investigations of cysteine mutant PLY and wild type confirmed the cysteine-mediated reversible covalent interaction between PB-3 and PLY. Afterwards, PB-3 was observed barely active against other cysteine-proteases (PTP-1B and SARS-CoV2), confirming the increased affinity of PB-3 toward PLY. PB-3 blocked PLY in a bacterial infection-model assay, this experiment further affirms selectively of PB-3 to PLY because the cell culture medium contained 13000-fold more free-cysteine than PLY. Finally, PB-3 was examined against two further CDC, PFO and ILY. PFO is analogous to PLY and possesses a cysteine residue in the undecapeptide and when PB-3 was tested, it was nearly 10 times more potent against PFO than PLY. Conversely, ILY is devoid of cysteine and PB-3 was expectedly inactive against ILY. In the light of these results, we presumably consider PB-3 as an inhibitor of cysteine-containing CDC.Cholesterin-abhängige Cytolysine (CDC) sind anerkannte Virulenzfaktoren einer breiten Palette pathogener grampositiver Bakterien wie Streptokokken, Clostridien und Listerien usw. CDC zielen selektiv auf Membranen ab, die Cholesterin enthalten, und induzieren die Pathogenese in den Wirtsorganismen durch vielseitige Mechanismen. Bakterien setzen während einer Infektion CDCs frei, die die Invasivität der Infektion erhöhen, und die Behandlung von Infektionen wird mit der derzeitigen Therapie mit Antiinfektiva zu einer Herausforderung. Zu den schädlichen Reaktionen von CDC gehören die direkte Toxizität über die Porenbildung, die Manipulation der zellulären Signalübertragung zur Förderung des bakteriellen Überlebens und die Umgehung des Immunsystems. Millionen von Todesfällen weltweit sind mit CDC wie PLY, PFO, LLO usw. verbunden. Daher wurden CDC als potenzielles Arzneimittelziel angesehen. Während der Forschung der letzten Jahrzehnte wurden mehrere natürliche und synthetische kleine Moleküle als Antitoxine vorgeschlagen, aufgrund mangelnder Spezifität wurde jedoch keines von ihnen für klinische Tests in Betracht gezogen. In unserer früheren Forschung wurde ein Modell von PLY-Poren entwickelt, um virtuell eine halbe Million Moleküle aus Online-Datenbanken zu Screening, die die Oligomerisierung und letztendlich die Porenbildung von PLY blockieren könnten. Pore Blocker-1 (PB-1) war das einzige Molekül, das PLY in einem Hämolyse-Assay aktiv hemmte, und seine Optimierung führte anschließend zur Entdeckung von PB-2 mit zehnfach verbesserter Aktivität. In dieser Dissertation wurden PB-1 und 2 mit dem BLI-Test validiert. Die Cryo-TEM-Analyse zeigte, dass PB-2 das Eindringen von PLY in die Membranen von Cholesterin-Liposomen verhinderte. Das Pharmakophor der Inhibitoren wurde durch die Analyse mehrerer eng verwandter Derivate von PB-2 identifiziert, was eine effektive Veränderung der Gerüste ermöglichte, um PB-3, einen chemisch stabileren und stärkeren Inhibitor von PLY, zu entwickeln. PB-3 hatte eine IC50 von 3 µM im Hämolyse-Assay und einen KD-Wert von 256 nM für PLY im BLI-Assay. Eine ähnliche Wirksamkeit von PB-3 wurde im LDH-Assay und in der Zellmikroskopie nachgewiesen. PB-3 wurde durch die protein-katalysierte Ligation von Precursor-Fragmenten erzeugt und quantifiziert. PB-3 wurde durch die Proteintemplat-unterstützte Ligation von Precursor-Fragmenten erzeugt und quantifiziert. Der wahre Mechanismus der Inhibitoren wurde durch die Auswertung der Aktivität der Inhibitoren gegen mehrere PLY-Mutanten entdeckt. Im Kontrast zu dem virtuell vorgeschlagenen Bindungsmechanismus deutete eine Cystein-Mutante von PLY darauf hin, dass PB-3 an ein Cystein in der Membran-Bindungsdomäne von PLY binden könnte. Anschließend bestätigten BLI und MS Untersuchungen der Cystein-Mutante PLY und des Wildtyps die Cystein-vermittelte reversible kovalente Interaktion zwischen PB-3 und PLY. Im Anschluss daran wurde PB-3 als kaum aktiv gegen andere Cystein-Proteasen (PTP-1B und SARS-CoV2) identifiziert, was die erhöhte Affinität von PB-3 gegenüber PLY bestätigt. PB-3 blockierte PLY in einem bakteriellen Infektionsmodell-Assay. Dieses Experiment bestätigt außerdem die Selektivität von PB-3 für PLY, da das Zellkulturmedium 13000-mal mehr freies Cystein als PLY enthielt. Zum Schluss wurde PB-3 gegen zwei weitere CDC, PFO und ILY, getestet. PFO ist analog zu PLY und enthält Cystein, und bei der Prüfung von PB-3 wurde festgestellt, dass es fast zehnmal stärker gegen PFO wirkt als PLY. Umgekehrt ist ILY frei von Cystein und PB-3 war erwartungsgemäß inaktiv gegenüber ILY. In Anbetracht dieser Ergebnisse halten wir PB-3 vermutlich für einen Hemmstoff gegen Cystein-haltiges CDC

    Cardiotoxic effects of anthracyclines in oncological treatment

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    Anthracyclines are antitumor antibiotics used during chemotherapy in cancer patients. Treatment with anthracyclines has good results but a side effect is significant cardiotoxicity. This bachelor thesis describes the mechanisms of action of anthracyclines which are essential in cancer therapy and may be risky for patients. The thesis also defines the term of cardiotoxicity and summarizes factors that may increase the risk of cardiotoxicity. The most commonly used agents in the anthracycline series are briefly described. Cardiotoxicity can be detected by cardiac markers, especially particular troponin and diagnostic methods. The last chapter describes the groups of substances that reduce the cardiotoxic effects of anthracyclines. Key words: heart, anthracyclines, cardiotoxicity, chemotherapy, onkology treatmentAntracykliny jsou protinádorová antibiotika používána během chemoterapie u onkologických pacientů. Léčba antracykliny má dobré výsledky, vedlejším účinkem je však značná kardiotoxicita. Tato bakalářská práce popisuje mechanismy působení antracyklinů, které jsou podstatné při nádorové terapii a zároveň mohou být pro pacienty rizikové. V práci je také definován pojem kardiotoxicita a shrnuty faktory, které mohou zvyšovat riziko kardiotoxicity. Nejpoužívanější látky z řady antracyklinů jsou stručně popsány. Kardiotoxicitu lze odhalit díky kardiomarkerům zejména díky troponinu a diagnostickým metodám. V poslední kapitole jsou popsány skupiny látek snižující kardiotoxické účinky antracyklinů. Klíčová slova: srdce, antracykliny, kardiotoxicita, chemoterapie, onkologická léčbaDepartment of PhysiologyKatedra fyziologieFaculty of SciencePřírodovědecká fakult

    Cardiovascular toxicity from therapies for light chain amyloidosis

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    Amyloid light-chain (AL) amyloidosis is a hematological disorder characterized by abnormal proliferation of a plasma cell clone producing monoclonal free light chains that misfold and aggregate into insoluble fibrils in various tissues. Cardiac involvement is a common feature leading to restrictive cardiomyopathy and poor prognosis. Current first-line treatments aim at achieving hematological response by targeting the plasma cell clones, and these have been adapted from multiple myeloma therapy. Patients with AL amyloidosis often exhibit multiorgan involvement, making them susceptible to cancer therapy-related cardiovascular toxicity. Managing AL amyloidosis is a complex issue that requires enhanced knowledge of the cardio-oncological implications of hematological treatments. Future research should focus on implementing and validating primary and secondary prevention strategies and understanding the biochemical basis of oncological therapy-related damage to mitigate cardiovascular toxicity

    Exploring the role of Wnt signalling in heart failure with preserved ejection fraction.

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    According to the European Society of Cardiology long-term out-patient registry, heart failure with preserved ejection fraction (HFpEF) accounts for approximately 16% of heart failure cases, with survival rates failing to improve due to the lack of effective treatments and the increasing prevalence of co-morbidities. It has been widely documented throughout the literature that Wingless/int1 (Wnt) signalling plays a role in the development of both cardiomyocyte hypertrophy and cardiac fibrosis, which are key features of HFpEF. Useful in vivo models of HFpEF are lacking; however, a recently-published 'two-hit' (metabolic and mechanical stress) in vivo model of HFpEF shows promise. Targeting Wnt signalling as a potential therapeutic intervention in this HFpEF model has not yet been investigated, so the present study was therefore carried out in order to investigate whether pharmacological inhibition of Wnt signalling could improve detrimental structural and/or functional changes associated with HFpEF. The present study aimed to: 1) examine the role of Wnt signalling in cardiomyocyte hypertrophy; 2) investigate whether Wnt signalling contributes to the development of HFpEF using an in vivo model of the condition; and 3) determine whether the administration of a Wnt inhibitor (Wnt-c59) alters the maladaptive structural and/or functional changes associated with HFpEF. Initial in vitro experiments using H9c2 cells determined the optimum experimental conditions for AngII (1μM)-induced cardiomyocyte hypertrophy. Furthermore, subsequent experiments determined that AngII-induced cardiomyocyte hypertrophy is mediated, at least in part, via activation of canonical Wnt signalling; this thesis is the first to demonstrate this pro-hypertrophic pathway in human cardiomyocytes. A role for Wnt signalling in the pathogenesis of HFpEF (a condition characterised by cardiac hypertrophy) was then examined in an in vivo model of the condition, induced by the chronic administration of a high fat diet and Nω-nitro-L-arginine methyl ester (L-NAME; 0.5g/L) to mice for 7 weeks. Findings from this study demonstrated that this mouse model of HFpEF was characterised by hypertension, cardiac hypertrophy and fibrosis, diastolic dysfunction (measured via pressure volume loop analysis), but there was no evidence demonstrating activation of canonical Wnt signalling in the hearts of these animals. Thus, on the basis of this study, a role for canonical Wnt signalling in the development of HFpEF is not supported. Notwithstanding this, treatment of HFpEF mice with Wnt-c59 (5mg/kg/day) did ameliorate diastolic dysfunction via mechanisms that may contribute to increased ventricular compliance, such as BNP-induced phosphorylation of titin and/or favourable regulation of the ratio of collagen subtype expression. However, this requires further investigation. In conclusion, this study has identified a hypertrophic role for Wnt signalling in vitro, indicating a link between renin angiotensin-aldosterone system (RAAS) activation and the initiation of Wnt signalling. Furthermore, in the 'two-hit' model of HFpEF there was no evidence of activation of canonical Wnt signalling; however, treatment of HFpEF mice with Wnt-c59 did ameliorate diastolic dysfunction via mechanisms that may contribute to increased ventricular compliance

    Diagnosis and Management of Heart Failure

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    Heart failure prevalence continues to rise globally. Regardless of the underlying etiology, heart failure remains a progressive disease, largely irreversible and end-stage heart failure requires transplantation. Book focuses on the challenges and recent advances of diagnosis, treatment and prevention of heart failure with or without associated comorbidities. We hope that readers will appreciate the wide breadth of topics and clinical utility of the articles and reviews included to this book collection

    Cardiac Arrhythmias

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    Cardiac arrhythmias are common triggers of emergency admission to cardiology or high-dependency departments. Most cases are easy to diagnose and treat, while others may present a challenge to healthcare professionals. A translational approach to arrhythmias links molecular and cellular scientific research with clinical diagnostics and therapeutic methods, which may include both pharmacological and non-pharmacologic treatments. This book presents a comprehensive overview of specific cardiac arrhythmias and discusses translational approaches to their diagnosis and treatment
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