A technical review of optical mapping of intracellular calcium within myocardial tissue

Jaimes, Rafael; Walton, Richard D.; Pasdois, Philippe; Bernus, Olivier; Efimov, Igor R.; Kay, Matthew W.

doi:10.1152/ajpheart.00665.2015

Cited by 69 publications

(74 citation statements)

References 123 publications

(145 reference statements)

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“…Following image acquisition, signal or image processing was performed as outlined in Figure 1D. Signal processing and data analysis were performed using a custom MATLAB script(26,50). A circular region of interest was taken in the center of the raw image with a 30-pixel radius (5-20 mm 2 area on the heart, depending on lens), averaged, and plotted against time.…”

Section: Methodsmentioning

confidence: 99%

“…They include: Di-4-ANEPPS with Indo-1(16), Di-2-ANEPEQ and Calcium green(23), and RH237 with Fluo-3/4/5N(12,15,24,25). Importantly, these dye combinations can have spectral overlap, necessitate non-ideal emission bandpass to negate spectral overlap, and/or include a calcium probe with an inferior dissociation constant(26). A dual-sensor optical mapping system offers many advantages, including the full spatial and temporal resolution of each individual camera.…”

Section: Introductionmentioning

confidence: 99%

“…A single-sensor, sequential imaging approach was described by Lee et al, which achieved rapid excitation light switching by utilizing recently developed high-power light emitting diodes(10). Accordingly, single-sensor designs use dual-dye combinations that require two (or more) excitation light sources, but share a single emission band, including: di-4-ANBDQPQ and Fura-2(10) or Rhod-2AM(29), Di-4-ANBDQBS and Fluo-4(28), or Di-4-ANEPPS and X-Rhod-1(11) (for review see(26)). Single-sensor optical mapping systems offer a cost advantage, since the camera sensor is often one of the most expensive components of an optical mapping setup.…”

Section: Introductionmentioning

confidence: 99%

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Lights, Camera, Path Splitter: A New Approach for Truly Simultaneous Dual Optical Mapping of the Heart with a Single Camera

Jaimes

McCullough

Siegel

et al. 2019

Preprint

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1Background: Optical mapping of transmembrane voltage and intracellular calcium is a powerful tool for 3 2 investigating cardiac physiology and pathophysiology. Until recently, the assembly and implementation 3 3 of simultaneous dual mapping of two fluorescent probes has been technically challenging. We 3 4introduce a novel, easy-to-use platform that requires only a single camera and single excitation light to 3 5 simultaneously acquire voltage and calcium signals from whole heart preparations, which can be 3 6expanded and applied to other physiological models -including neurons and isolated cardiomyocytes. 3 7Results: Complementary probes were selected that could be excited with a single wavelength light 3 8source. Langendorff-perfused hearts (rat, swine) were stained and then imaged using a sCMOS 3 9camera outfitted with an optical path splitter to simultaneously acquire two emission fields at high 4 0spatial and temporal resolution. Voltage (RH237) and calcium (Rhod2-AM) signals were acquired 4 1 concurrently on a single sensor, resulting in two 384x256 images at 814 frames per second. At this 4 2 frame rate, the signal-to-noise ratio was 47 (RH237) and 85 (Rhod-2AM). In separate experiments, 4 3 each dye was used independently to assess crosstalk and demonstrate signal specificity. Additionally, 4 4the effect of ryanodine on myocardial calcium transients was validated -with no measurable effect on 4 5the amplitude of optical action potentials. To demonstrate spatial resolution, ventricular tachycardia was 4 6induced and spatially discordant alternans were noted in different regions of the heart. 4 7Conclusions: We present and validate a dual imaging approach that eliminates the need for multiple 4 8 cameras, excitation light patterning or frame interleaving. This imaging platform is comprised entirely of 4

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lights, Camera, Path Splitter: A New Approach for Truly Simultaneous Dual Optical Mapping of the Heart with a Single Camera

Jaimes

McCullough

Siegel

et al. 2019

Preprint

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“…As a result, little is known about calcium dynamics at the level of single cardiomyocytes in the in vivo environment. Previous in vivo studies of calcium dynamics utilized wide-field fluorescence imaging that primarily reports surface calcium transients averaged across many cells 10,11 , while cell-resolved calcium imaging has relied on reduced preparations such as ex vivo Langendorf perfusion models, which eliminate both blood flow and cardiomyocyte contraction 12,13 . Here, we demonstrated methods for imaging activity of the genetically encoded calcium indicator, GCaMP6f 7 , in the beating heart within a living mouse with the capability to resolve single cardiomyocytes, measure calcium dynamics as a function of depth into the ventricle wall, and characterize the dependence on both cardiac and respiratory cycles.…”

Section: Main Textmentioning

confidence: 99%

In vivo multiphoton microscopy of cardiomyocyte calcium dynamics in the beating mouse heart

Nishimura

2018

Preprint

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We demonstrated intravital multiphoton microscopy in the beating heart in an intact mouse and optically measured action potentials with GCaMP6f, a genetically-encoded calcium indicator. Images were acquired at 30 fps with spontaneous heart beat and continuously running ventilated breathing. The data were reconstructed into threedimensional volumes showing tissue structure, displacement, and GCaMP activity in cardiomyocytes as a function of both the cardiac and respiratory cycle. Main textIn vivo multiphoton microscopy (MPM) was recently demonstrated within the heart of rodent models [1][2][3][4][5][6] . However, the combined use of intravital MPM and genetically encoded calcium indicators, which has revolutionized brain studies by enabling in vivo measurement of action potentials from individual neurons within a genetically-defined cell population 7-9 , has not been achieved in the heart. As a result, little is known about calcium dynamics at the level of single cardiomyocytes in the in vivo environment. Previous in vivo studies of calcium dynamics utilized wide-field fluorescence imaging that primarily reports surface calcium transients averaged across many cells 10,11 , while cell-resolved calcium imaging has relied on reduced preparations such as ex vivo Langendorf perfusion models, which eliminate both blood flow and cardiomyocyte contraction 12,13 . Here, we demonstrated methods for imaging activity of the genetically encoded calcium indicator, GCaMP6f 7 , in the beating heart within a living mouse with the capability to resolve single cardiomyocytes, measure calcium dynamics as a function of depth into the ventricle wall, and characterize the dependence on both cardiac and respiratory cycles.In anesthetized, mechanically ventilated mice, we acquired ~100-µm thick image stacks with 2-µm step size and 50-100 images per plane through a window mounted to a stabilized probe glued to the left ventricle ( Fig. 1a and b, Supple. Fig.1) while recording the electrocardiogram (ECG) and ventilator pressure (Fig. 1c). This preparation caused minimal tissue damage (Supple. Fig. 2a) and heart rate was stable throughout the imaging session (Supple. Fig. 2b). High frame rate imaging (30 fps), using resonant scanners, produced clear images in real time throughout the cardiac cycle, with less distortion due to tissue motion than with slower scanning with . CC-BY-NC-ND 4.0 International license It is made available under a (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint . http://dx.doi.org/10.1101/251561 doi: bioRxiv preprint first posted online Jan. 22, 2018; 3 galvanometers (Supple. Fig. 3). In contrast to previous approaches 2,3 , breathing was not paused during measurement and image acquisition and heart beat were not synchronized. Instead, the effects of breathing and heart beat were decoupled by reconstructing 3D volumes from smaller image segments sorted by both the cardiac and respiratory pha...

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“…Following image acquisition, signal processing and data analysis were performed using a custom 161 MATLAB script, as previously described (Posnack et al, 2014b;Jaimes et al, 2016b). A region of 162 interest (appx 0.75 mm) was selected in identical locations on the split image of the heart for each raw image.…”

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confidence: 99%

Age-dependent changes in electrophysiology and calcium handling – implications for pediatric cardiac research

Swift

Burke

Guerrelli

et al. 2019

Preprint

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28 29Rationale: The heart continues to develop and mature after birth and into adolescence. Accordingly, 30 cardiac maturation is likely to include a progressive refinement in both organ morphology and function 31 during the postnatal period. Yet, age-dependent changes in cardiac electrophysiology and calcium 32 handling have not yet been fully characterized. 33Objective: The objective of this study, was to examine the relationship between cardiac maturation, 34 electrophysiology, and calcium handling throughout postnatal development in a rat model. 35 Methods: Postnatal rat cardiac maturation was determined by measuring the expression of genes 36 involved in cell-cell coupling, electrophysiology, and calcium handling. In vivo electrocardiograms were 37 recorded from neonatal, juvenile, and adult animals. Simultaneous dual optical mapping of 38 transmembrane voltage and calcium transients was performed on isolated, Langendorff-perfused rat 39 hearts (postnatal day 0-3, 4-7, 8-14, adult).40 Results: Younger, immature hearts displayed slowed electrical conduction, prolonged action potential 41 duration and increased ventricular refractoriness. Slowed calcium handling in the immature heart 42 increased the propensity for calcium transient alternans which corresponded to alterations in the 43 expression of genes encoding calcium handling proteins. Developmental changes in cardiac 44 electrophysiology were associated with the altered expression of genes encoding potassium channels 45 and intercalated disc proteins.46 Conclusion: Using an intact whole heart model, this study highlights chronological changes in cardiac 47 electrophysiology and calcium handling throughout postnatal development. Results of this study can 48 serve as a comprehensive baseline for future studies focused on pediatric cardiac research, safety 49 assessment and/or preclinical testing using rodent models.50 51

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A technical review of optical mapping of intracellular calcium within myocardial tissue

Abstract: Jaimes R 3rd, Walton RD, Pasdois P, Bernus O, Efimov IR, Kay MW. A technical review of optical mapping of intracellular calcium within myocardial tissue.

Cited by 69 publications

References 123 publications

Lights, Camera, Path Splitter: A New Approach for Truly Simultaneous Dual Optical Mapping of the Heart with a Single Camera

Lights, Camera, Path Splitter: A New Approach for Truly Simultaneous Dual Optical Mapping of the Heart with a Single Camera

In vivo multiphoton microscopy of cardiomyocyte calcium dynamics in the beating mouse heart

Age-dependent changes in electrophysiology and calcium handling – implications for pediatric cardiac research

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