Bronchodilator aminophylline may induce atrial or less often ventricular arrhythmias. The mechanism of this proarrhythmic side effect has not been fully explained. Modifications of inward rectifier potassium (Kir) currents including IK1 are known to play an important role in arrhythmogenesis; however, no data on the aminophylline effect on these currents have been published. Hence, we tested the effect of aminophylline (3-100 μM) on IK1 in enzymatically isolated rat ventricular myocytes using the whole-cell patch-clamp technique. A dual steady-state effect of aminophylline was observed; either inhibition or activation was apparent in individual cells during the application of aminophylline at a given concentration. The smaller the magnitude of the control IK1, the more likely the activation of the current by aminophylline and vice versa. The effect was reversible; the relative changes at -50 and -110 mV did not differ. Using IK1 channel population model, the dual effect was explained by the interaction of aminophylline with two different channel populations, the first one being inhibited and the second one being activated. Considering various fractions of these two channel populations in individual cells, varying effects observed in the measured cells could be simulated. We propose that the dual aminophylline effect may be related to the direct and indirect effect of the drug on various Kir2.x subunits forming the homo- and heterotetrameric IK1 channels in a single cell. The observed IK1 changes induced by clinically relevant concentrations of aminophylline might contribute to arrhythmogenesis related to the use of this bronchodilator in clinical medicine.
- MeSH
- aminofylin škodlivé účinky MeSH
- bronchodilatancia škodlivé účinky MeSH
- draslík farmakologie MeSH
- draslíkové kanály dovnitř usměrňující * MeSH
- kardiomyocyty fyziologie MeSH
- krysa rodu rattus MeSH
- srdeční arytmie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Heart remodeling occurs as a compensation mechanism for the massive loss of tissue during initial heart failure and the consequent inflammation process. During heart remodeling fibroblasts differentiate to myofibroblasts activate their secretion functions and produce elevated amounts, of extracellular matrix (ECM) proteins, mostly collagen, that form scar tissue and alter the normal degradation of ECM. Scar formation does replace the damaged tissue structurally; however, it impedes the normal contractive function of cardiomyocytes (CMs) and results in long-lasting effects after heart failure. Besides CMs and cardiac fibroblasts, endothelial cells (ECs) and circulating endothelial progenitor cells (cEPCs) contribute to heart repair. This review summarizes the current knowledge of EC-CM crosstalk in cardiac fibrosis (CF), the role of cEPCs in heart regeneration and the contribution of Endothelial-mesenchymal transition (EndoMT).
- MeSH
- endoteliální buňky fyziologie MeSH
- endoteliální progenitorové buňky fyziologie MeSH
- interakce mezi receptory a ligandy MeSH
- kardiomyocyty fyziologie MeSH
- lidé MeSH
- regenerace * MeSH
- remodelace komor * MeSH
- srdce fyziologie MeSH
- transdiferenciace buněk * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- MeSH
- buněčná membrána fyziologie MeSH
- elektrofyziologie normy MeSH
- kardiologie normy MeSH
- kardiomyocyty fyziologie MeSH
- lidé MeSH
- reprodukovatelnost výsledků MeSH
- vápník metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- úvodní články MeSH
- úvodníky MeSH
The stimulation of myocardium repair is restricted due to the limited understanding of heart regeneration. Interestingly, endogenous opioid peptides such as dynorphins and enkephalins are suggested to support this process. However, the mechanism-whether through the stimulation of the regenerative capacity of cardiac stem cells or through effects on other cell types in the heart-is still not completely understood. Thus, a model of the spontaneous cardiomyogenic differentiation of mouse embryonic stem (mES) cells via the formation of embryoid bodies was used to describe changes in the expression and localization of opioid receptors within cells during the differentiation process and the potential of the selected opioid peptides, dynorphin A and B, and methionin-enkephalins and leucin-enkephalins, to modulate cardiomyogenic differentiation in vitro. The expressions of both κ- and δ-opioid receptors significantly increased during mES cell differentiation. Moreover, their primary colocalization with the nucleus was followed by their growing presence on the cytoplasmic membrane with increasing mES cell differentiation status. Interestingly, dynorphin B enhanced the downregulation gene expression of Oct4 characteristic of the pluripotent phenotype. Further, dynorphin B also increased cardiomyocyte-specific Nkx2.5 gene expression. However, neither dynorphin A nor methionin-enkephalins and leucin-enkephalins exhibited any significant effects on the course of mES cell differentiation. In conclusion, despite the increased expression of opioid receptors and some enhancement of mES cell differentiation by dynorphin B, the overall data do not support the notion that opioid peptides have a significant potential to promote the spontaneous cardiomyogenesis of mES cells in vitro.
- MeSH
- buněčná diferenciace fyziologie MeSH
- kardiomyocyty cytologie fyziologie MeSH
- myokard cytologie MeSH
- myší embryonální kmenové buňky cytologie metabolismus MeSH
- myši MeSH
- opioidní peptidy metabolismus MeSH
- receptory opiátové metabolismus MeSH
- regenerace fyziologie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Cardiac damage is one of major cause of worldwide morbidity and mortality. Despite the development in pharmacotherapy, cardiosurgery and interventional cardiology, many patients remain at increased risk of developing adverse cardiac remodeling. An alternative treatment approach is the application of stem cells. Mesenchymal stem cells are among the most promising cell types usable for cardiac regeneration. Their homing to the damaged area, differentiation into cardiomyocytes, paracrine and/or immunomodulatory effect on cardiac tissue was investigated extensively. Despite promising preclinical reports, clinical trials on human patients are not convincing. Meta-analyses of these trials open many questions and show that routine clinical application of mesenchymal stem cells as a cardiac treatment may be not as helpful as expected. This review summarizes contemporary knowledge about mesenchymal stem cells role in cardiac tissue repair and discusses the problems and perspectives of this experimental therapeutical approach.
- MeSH
- kardiomyocyty fyziologie MeSH
- kardiovaskulární nemoci patologie terapie MeSH
- lidé MeSH
- mezenchymální kmenové buňky cytologie MeSH
- myokard MeSH
- regenerace fyziologie MeSH
- regenerativní lékařství * MeSH
- transplantace mezenchymálních kmenových buněk metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Infection with Trypanosoma cruzi Chagas, 1909 is reported to increase the production of reactive oxygen species in patients with Chagas disease. Mitochondria dysfunction, host inflammatory response and inadequate antioxidant response are described as the main factors leading to oxidative stress during acute and chronic stages of the disease. The Seahorse XFe24 extracellular flux platform allows energy metabolism determination through mitochondrial respiration and glycolysis measurements. XFe24 platform can be used in in vitro models of T. cruzi-infected cells, which allow the assessment and even modulation of endogenous conditions of infected cells, generating readouts of real-time cellular bioenergetics changes. In this protocol, we standardised the use of XFe24 technology in T. cruzi infected AC16 cardiomyocytes and SGHPL-5 trophoblasts. In addition, we provide a list of optimised assay specifications, advantages and critical steps to be considered during the process. Cardiomyocytes and trophoblasts are attractive target cells to evaluate the metabolic environment in acute, chronic and congenital Chagas transmission scenarios.
- MeSH
- buněčné dýchání MeSH
- buněčné linie MeSH
- kardiomyocyty parazitologie fyziologie MeSH
- lidé MeSH
- mitochondrie parazitologie fyziologie MeSH
- myši MeSH
- reaktivní formy kyslíku MeSH
- trofoblasty parazitologie fyziologie MeSH
- Trypanosoma cruzi fyziologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The cardiac excitation-contraction coupling is the cellular process through which the heart absolves its blood pumping function, and it is directly affected when cardiac pathologies occur. Cardiomyocytes are the functional units in which this complex biomolecular process takes place: they can be represented as a two-stage electro-chemo and chemo-mechanical transducer, along which each stage can be probed and monitored via appropriate micro/nanotechnology-based tools. Atomic force microscopy (AFM), with its unique nanoresolved force sensitivity and versatile modes of extracting sample properties, can represent a key instrument to study time-dependent heart mechanics and topography at the single cell level. In this work, we show how the integrative possibilities of AFM allowed us to implement an in vitro system which can monitor cardiac electrophysiology, intracellular calcium dynamics, and single cell mechanics. We believe this single cell-sensitive and integrated system will unlock improved, fast, and reliable cardiac in vitro tests in the future.
- MeSH
- analýza dat MeSH
- elektrofyziologické jevy * MeSH
- kardiomyocyty cytologie fyziologie MeSH
- mechanické jevy * MeSH
- mikroskopie atomárních sil * přístrojové vybavení metody MeSH
- molekulární zobrazování MeSH
- spřažení excitace a kontrakce * MeSH
- vápníková signalizace MeSH
- Publikační typ
- časopisecké články MeSH
Pioglitazone (PIO) is a thiazolidindione antidiabetic agent which improves insulin sensitivity and reduces blood glucose in experimental animals and treated patients. At the cellular level the actions of PIO in diabetic heart are poorly understood. A previous study has demonstrated shortened action potential duration and inhibition of a variety of transmembrane currents including L-type Ca(2+) current in normal canine ventricular myocytes. The effects of PIO on shortening and calcium transport in ventricular myocytes from the Goto-Kakizaki (GK) type 2 diabetic rat have been investigated. 10 min exposure to PIO (0.1-10 microM) reduced the amplitude of shortening to similar extents in ventricular myocytes from GK and control rats. 1 microM PIO reduced the amplitude of the Ca(2+) transients to similar extents in ventricular myocytes from GK and control rats. Caffeine-induced Ca(2+) release from the sarcoplasmic reticulum and recovery of Ca(2+) transients following application of caffeine and myofilament sensitivity to Ca(2+) were not significantly altered in ventricular myocytes from GK and control rats. Amplitude of L-type Ca(2+) current was not significantly decreased in myocytes from GK compared to control rats and by PIO treatment. The negative inotropic effects of PIO may be attributed to a reduction in the amplitude of the Ca(2+) transient however, the mechanisms remain to be resolved.
- MeSH
- biologický transport účinky léků MeSH
- diabetes mellitus 2. typu farmakoterapie patofyziologie MeSH
- experimentální diabetes mellitus farmakoterapie patofyziologie MeSH
- hypoglykemika farmakologie terapeutické užití MeSH
- kardiomyocyty účinky léků fyziologie MeSH
- kontrakce myokardu účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- srdeční komory účinky léků MeSH
- thiazolidindiony farmakologie terapeutické užití MeSH
- vápníková signalizace účinky léků fyziologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Inward rectifier potassium currents (I Kir,x) belong to prominent ionic currents affecting both resting membrane voltage and action potential repolarization in cardiomyocytes. In existing integrative models of electrical activity of cardiac cells, they have been described as single current components. The proposed quantitative model complies with findings indicating that these channels are formed by various homomeric or heteromeric assemblies of channel subunits with specific functional properties. Each I Kir,x may be expressed as a total of independent currents via individual populations of identical channels, i.e., channels formed by the same combination of their subunits. Solution of the model equations simulated well recently observed unique manifestations of dual ethanol effect in rat ventricular and atrial cells. The model reflects reported occurrence of at least two binding sites for ethanol within I Kir,x channels related to slow allosteric conformation changes governing channel conductance and inducing current activation or inhibition. Our new model may considerably improve the existing models of cardiac cells by including the model equations proposed here in the particular case of the voltage-independent drug-channel interaction. Such improved integrative models may provide more precise and, thus, more physiologically relevant results.
- MeSH
- akční potenciály * MeSH
- alosterická regulace MeSH
- draslíkové kanály dovnitř usměrňující chemie metabolismus MeSH
- ethanol farmakologie MeSH
- kardiomyocyty účinky léků metabolismus fyziologie MeSH
- krysa rodu rattus MeSH
- modely kardiovaskulární MeSH
- multimerizace proteinu MeSH
- srdce - funkce komor MeSH
- srdeční komory cytologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Mesenchymal stem cells (MSCs) have been reported to improve survival of cardiomyocytes (CMCs) and overall regeneration of cardiac tissue. Despite promising preclinical results, interactions of MSCs and CMCs, both direct and indirect, remain unclear. In this study, porcine bone marrow MSCs and freshly isolated porcine primary adult CMCs were used for non-contact co-culture experiments. Morphology, viability and functional parameters of CMCs were measured over time and compared between CMCs cultured alone and CMCs co-cultured with MSCs. In non-contact co-culture, MSCs improved survival of CMCs. CMCs co-cultured with MSCs maintained CMCs morphology and viability in significantly higher percentage than CMCs cultured alone. In viable CMCs, mitochondrial respiration was preserved in both CMCs cultured alone and in CMCs co-cultured with MSCs. Comparison of cellular contractility and calcium handling, measured in single CMCs, revealed no significant differences between viable CMCs from co-culture and CMCs cultured alone. In conclusion, non-contact co-culture of porcine MSCs and CMCs improved survival of CMCs with a sufficient preservation of functional and mitochondrial parameters.
- MeSH
- kardiomyocyty fyziologie MeSH
- kokultivační techniky metody MeSH
- mezenchymální kmenové buňky fyziologie MeSH
- mitochondrie fyziologie MeSH
- prasata MeSH
- průtoková cytometrie metody MeSH
- věkové faktory MeSH
- viabilita buněk fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
