2,3-dehydrosilybin (DHS) is a minor flavonolignan component of Silybum marianum seed extract known for its hepatoprotective activity. Recently we identified DHS as a potentially cardioprotective substance during hypoxia/reoxygenation in isolated neonatal rat cardiomyocytes. This is the first report of positive inotropic effect of DHS on perfused adult rat heart. When applied to perfused adult rat heart, DHS caused a dose-dependent inotropic effect resembling that of catecholamines. The effect was apparent with DHS concentration as low as 10 nM. Suspecting direct interaction with β-adrenergic receptors, we tested whether DHS can trigger β agonist-dependent gene transcription in a model cell line. While DHS alone was unable to trigger β agonist-dependent gene transcription, it enhanced the effect of isoproterenol, a known unspecific β agonist. Further tests confirmed that DHS could not induce cAMP accumulation in isolated neonatal rat cardiomyocytes even though high concentrations (≥ 10 μM) of DHS were capable of decreasing phosphodiesterase activity. Pre-treatment of rats with reserpine, an indole alkaloid which depletes catecholamines from peripheral sympathetic nerve endings, abolished the DHS inotropic effect in perfused hearts. Our data suggest that DHS causes the inotropic effect without acting as a β agonist. Hence we identify DHS as a novel inotropic agent.

• MeSH
• buněčné linie MeSH
• kardiomyocyty fyziologie   MeSH
• kardiotonika farmakologie   MeSH
• kontrakce myokardu účinky léků   MeSH
• krysa rodu Rattus MeSH
• ostropestřec mariánský MeSH
• potkani Wistar MeSH
• reserpin farmakologie   MeSH
• rostlinné přípravky farmakologie   MeSH
• silibinin MeSH
• silymarin farmakologie   MeSH
• srdce účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kardiotonika MeSH
• reserpin MeSH
• rostlinné přípravky MeSH
• silibinin MeSH
• silymarin MeSH

OBJECTIVE: Cell therapies have emerged as a promising approach in medicine. The basis of each therapy is the injection of 1-100×10(6) cells with regenerative potential into some part of the body. Mesenchymal stromal cells (MSCs) are the most used cell type in the cell therapy nowadays, but no gold standard for the labeling of the MSCs for magnetic resonance imaging (MRI) is available yet. This work evaluates our newly synthesized uncoated superparamagnetic maghemite nanoparticles (surface-active maghemite nanoparticles - SAMNs) as an MRI contrast intracellular probe usable in a clinical 1.5 T MRI system. METHODS: MSCs from rat and human donors were isolated, and then incubated at different concentrations (10-200 μg/mL) of SAMN maghemite nanoparticles for 48 hours. Viability, proliferation, and nanoparticle uptake efficiency were tested (using fluorescence microscopy, xCELLigence analysis, atomic absorption spectroscopy, and advanced microscopy techniques). Migration capacity, cluster of differentiation markers, effect of nanoparticles on long-term viability, contrast properties in MRI, and cocultivation of labeled cells with myocytes were also studied. RESULTS: SAMNs do not affect MSC viability if the concentration does not exceed 100 μg ferumoxide/mL, and this concentration does not alter their cell phenotype and long-term proliferation profile. After 48 hours of incubation, MSCs labeled with SAMNs show more than double the amount of iron per cell compared to Resovist-labeled cells, which correlates well with the better contrast properties of the SAMN cell sample in T2-weighted MRI. SAMN-labeled MSCs display strong adherence and excellent elasticity in a beating myocyte culture for a minimum of 7 days. CONCLUSION: Detailed in vitro tests and phantom tests on ex vivo tissue show that the new SAMNs are efficient MRI contrast agent probes with exclusive intracellular uptake and high biological safety.

• Klíčová slova
• magnetic resonance imaging, mesenchymal stromal cells, stem cell labeling, stem cell tracking, superparamagnetic iron oxide nanoparticles,
• MeSH
• buněčný tracking metody   MeSH
• dextrany chemie   farmakokinetika   toxicita   MeSH
• fyziologie buňky účinky léků   MeSH
• kontrastní látky chemie   farmakokinetika   toxicita   MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• magnetické nanočástice chemie   toxicita   MeSH
• mezenchymální kmenové buňky chemie   cytologie   účinky léků   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• dextrany MeSH
• ferumoxides MeSH Prohlížeč
• kontrastní látky MeSH
• magnetické nanočástice MeSH

Reactive oxygen species (ROS) originating from mitochondria are perceived as a factor contributing to cell aging and means have been sought to attenuate ROS formation with the aim of extending the cell lifespan. Silybin and dehydrosilybin, two polyphenolic compounds, display a plethora of biological effects generally ascribed to their known antioxidant capacity. When investigating the cytoprotective effects of these two compounds in the primary cell cultures of neonatal rat cardiomyocytes, we noted the ability of dehydrosilybin to de-energize the cells by monitoring JC-1 fluorescence. Experiments evaluating oxygen consumption and membrane potential revealed that dehydrosilybin uncouples the respiration of isolated rat heart mitochondria albeit with a much lower potency than synthetic uncouplers. Furthermore, dehydrosilybin revealed a very high potency in suppressing ROS formation in isolated rat heart mitochondria with IC(50) = 0.15 μM. It is far more effective than its effect in a purely chemical system generating superoxide or in cells capable of oxidative burst, where the IC(50) for dehydrosilybin exceeds 50 μM. Dehydrosilybin also attenuated ROS formation caused by rotenone in the primary cultures of neonatal rat cardiomyocytes. We infer that the apparent uncoupler-like activity of dehydrosilybin is the basis of its ROS modulation effect in neonatal rat cardiomyocytes and leads us to propose a hypothesis on natural ischemia preconditioning by dietary polyphenols.

• MeSH
• analýza rozptylu MeSH
• benzimidazoly MeSH
• fluorescenční barviva MeSH
• inhibiční koncentrace 50 MeSH
• karbocyaniny MeSH
• kardiomyocyty metabolismus   MeSH
• krysa rodu Rattus MeSH
• mitochondrie metabolismus   MeSH
• molekulární struktura MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• rotenon toxicita   MeSH
• silymarin chemie   farmakologie   MeSH
• spotřeba kyslíku účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine MeSH Prohlížeč
• benzimidazoly MeSH
• dehydrosilybin MeSH Prohlížeč
• fluorescenční barviva MeSH
• karbocyaniny MeSH
• reaktivní formy kyslíku MeSH
• rotenon MeSH
• silymarin MeSH