Estimation of the fractional sarcoplasmic reticulum Ca2+ release in intact cardiomyocytes using integrated Ca2+ fluxes

Bassani, Rosana A.; Ricardo, Rafael A.; Bassani, José Wilson Magalhães

doi:10.4149/gpb_2012_042

Cited by 7 publications

(14 citation statements)

References 36 publications

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“…Cardiac myocytes were isolated with collagenase digestion using a previously described technique64. Briefly, the hearts were attached via the aorta to a cannula, excised and mounted in a Langendorff apparatus.…”

Section: Methodsmentioning

confidence: 99%

“…The perfusion chamber containing the cells was placed on the stage of an inverted microscope (Nikon Diaphot 200) coupled to a microfluorimetry system (Photon Technology Intl, Inc.). The dye was excited at 360 nm, and the emission ratio at 410 and 485 nm was converted to [Ca 2+ ]i according to Bassani et al 64,. using calibration parameters determined in live cells.…”

Section: Methodsmentioning

confidence: 99%

“…The propensity to develop arrhythmias was estimated from the number of non-stimulated contractile events (NSE), which were defined as the spontaneous contractions developed after interruption of a 10 min-long stimulation train at either 0.5 or 3 Hz. To investigate the role of a possible increase in Ca 2+ extrusion rate via the Na + /Ca 2+ exchanger (NCX) as a factor that may facilitate the generation of Ca 2+ -dependent spontaneous electrical activity, the ratio of the rate constants of [Ca 2+ ]i decay at a caffeine-evoked transient and a twitch (in which cytosolic [Ca 2+ ]i removal is mainly attributable to the NCX and the SR Ca 2+ -ATPase, respectively), was compared in control and IL-1-treated myocytes64. To estimate the rest-dependent loss of the SR Ca 2+ content, which may occur in case of increased rate of diastolic SR Ca 2+ release25, the content of Ca 2+ stored in the SR (as ⌈moles Ca 2+ per liter of non-mitochondrial cell water) at steady-state was estimated from a Ca 2+ transient evoked by caffeine in Na + -, Ca 2+ -free solution26 after stimulation at 1 Hz for 3 min.…”

Section: Methodsmentioning

confidence: 99%

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Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice

et al. 2016

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Diabetes mellitus (DM) encompasses a multitude of secondary disorders, including heart disease. One of the most frequent and potentially life threatening disorders of DM-induced heart disease is ventricular tachycardia (VT). Here we show that toll-like receptor 2 (TLR2) and NLRP3 inflammasome activation in cardiac macrophages mediate the production of IL-1β in DM mice. IL-1β causes prolongation of the action potential duration, induces a decrease in potassium current and an increase in calcium sparks in cardiomyocytes, which are changes that underlie arrhythmia propensity. IL-1β-induced spontaneous contractile events are associated with CaMKII oxidation and phosphorylation. We further show that DM-induced arrhythmias can be successfully treated by inhibiting the IL-1β axis with either IL-1 receptor antagonist or by inhibiting the NLRP3 inflammasome. Our results establish IL-1β as an inflammatory connection between metabolic dysfunction and arrhythmias in DM.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice

et al. 2016

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“…The trend of increasing fractional Ca 2þ release, demonstrated by mES-CM cultured on scaffolds compared to mES-CM cultured in 2D suggests that a longer culture period on PVDF-TrFE scaffolds may promote fractional Ca 2þ release that is similar to native cardiomyocytes. It is shown that the physiological fractional Ca 2þ release of adult left ventricular rat cardiomyocytes is between 60% and 70% (Bassani et al, 2012). The increase in spontaneous contraction frequency in both mES-CM cultured in 2D and on PVDF-TrFE, with the treatment of isoproterenol, also suggests that these cells exhibit positive chronotropic responses to b-adrenergic stimulation, which is a hallmark of adult cardiomyocytes (He et al, 2003;Zhang et al, 2013).…”

Section: Discussionmentioning

confidence: 90%

The effect of PVDF‐TrFE scaffolds on stem cell derived cardiovascular cells

Hitscherich

Gordan

et al. 2016

Biotech & Bioengineering

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Recently, electrospun polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) scaffolds have been developed for tissue engineering applications. These materials have piezoelectric activity, wherein they can generate electric charge with minute mechanical deformations. Since the myocardium is an electroactive tissue, the unique feature of a piezoelectric scaffold is attractive for cardiovascular tissue engineering applications. In this study, we examined the cytocompatibility and function of pluripotent stem cell derived cardiovascular cells including mouse embryonic stem cell-derived cardiomyocytes (mES-CM) and endothelial cells (mES-EC) on PVDF-TrFE scaffolds. MES-CM and mES-EC adhered well to PVDF-TrFE and became highly aligned along the fibers. When cultured on scaffolds, mES-CM spontaneously contracted, exhibited well-registered sarcomeres and expressed classic cardiac specific markers such as myosin heavy chain, cardiac troponin T, and connexin43. Moreover, mES-CM cultured on PVDF-TrFE scaffolds responded to exogenous electrical pacing and exhibited intracellular calcium handling behavior similar to that of mES-CM cultured in 2D. Similar to cardiomyocytes, mES-EC also demonstrated high viability and maintained a mature phenotype through uptake of low-density lipoprotein and expression of classic endothelial cell markers including platelet endothelial cell adhesion molecule, endothelial nitric oxide synthase, and the arterial specific marker, Notch-1. This study demonstrates the feasibility of PVDF-TrFE scaffold as a candidate material for developing engineered cardiovascular tissues utilizing stem cell-derived cells. Biotechnol. Bioeng. 2016;113: 1577-1585. © 2015 Wiley Periodicals, Inc.

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“…Furthermore, culture on PCL + G scaffolds promoted a significantly higher fractional release of approximately 40% compared to that of mES‐CM cultured in 2D (approximately 26%). Fractional release is an indicator of excitation‐contraction coupling efficiency and the fractional release of mature rat is approximately 60% . A higher fractional release further suggests that Ca 2+ handling function of mES‐CM is enhanced with culture on 3D graphene containing scaffolds.…”

Section: Discussionmentioning

confidence: 99%

Electroactive graphene composite scaffolds for cardiac tissue engineering

Hitscherich

Aphale

Gordan

et al. 2018

J Biomedical Materials Res

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Contractile behavior of cardiomyocytes relies on directed signal propagation through the electroconductive networks that exist within the native myocardium. Due to their unique electrical properties, electroactive materials, such as graphene, have recently emerged as promising candidate materials for cardiac tissue engineering applications. In this work, the potential of three-dimensional (3D) nanofibrous graphene and poly(caprolactone) (PCL + G) composite scaffold for cardiac tissue engineering has been explored for the first time. The addition of graphene into PCL led to an increased volume conductivity of scaffolds with an even distribution of graphene particles throughout the matrix. Graphene particles provided local conductive sites within the PCL matrix, which enabled application of external electrical stimulation throughout the scaffold using a custom point stimulation device. When mouse embryonic stem cell derived cardiomyocytes (mES-CM) were seeded on PCL + G scaffolds, cells adhered well, contracted spontaneously, and exhibited classical cardiomyocyte phenotype confirming the biocompatibility of electroactive PCL + G scaffolds. Further functional characterization demonstrated that graphene especially affected Ca 2+ handling properties of mES-CM compared to that of cardiomyocytes cultured in 2D culture, highlighting the potential of PCL + G for in vitro cardiac tissue engineering.

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Estimation of the fractional sarcoplasmic reticulum Ca2+ release in intact cardiomyocytes using integrated Ca2+ fluxes

Abstract: Abstract. The sarcoplasmic reticulum (SR) is the main source of contraction-activating Ca 2+ in the adult mammalian myocardium.

Cited by 7 publications

References 36 publications

Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice

Macrophage-dependent IL-1β production induces cardiac arrhythmias in diabetic mice

The effect of PVDF‐TrFE scaffolds on stem cell derived cardiovascular cells

Electroactive graphene composite scaffolds for cardiac tissue engineering

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