Journal: Scientific Reports

Article Title: Overexpression of Cx43 in cells of the myocardial scar: Correction of post-infarct arrhythmias through heterotypic cell-cell coupling

doi: 10.1038/s41598-018-25147-8

Figure Lengend Snippet: Lentivirus-mediated Cx43 transduction of SkM results in functional gap junction formation in vitro and in vivo . ( a ) Scheme of the control EGFP and the bicistronic Cx43 lentiviral vectors. ( b ) Immunostainings of cultured, lentivirus transduced EGFP + (green, third panel from left; nuclear Hoechst stain, blue) SkM prove expression of MyoD (white, left panel) and membrane-located Cx43 (red, second panel from left); the right panel is an overlay of all three pictures. ( c ) In vitro dye transfer in differentiated transgenic myotubes (EGFP + , left); patch loading of the upper myotube (arrows) results in progressive dye transfer of Alexa 350 (middle left), but not of Alexa 546-dextran (middle right) into the neighbouring EGFP + SkM (arrowheads). A brightfield image (right) shows a dense monolayer of differentiated and elongated myocytes. ( d , e ) Sirius Red staining of infarcted hearts 12–14 days after the lesion reveals engraftment of EGFP ( d ) and Cx43-EGFP ( e ) ex vivo transduced SkM (fibrotic tissue red, viable cells yellow) in the transmural scar area. Macroscopic imaging and quantitative morphometry revealed in average 19.185 ± 18.743 and 5.338 ± 4.552 engrafted cells in EGFP-SkM and Cx43-SkM engrafted hearts, respectively (n = 5 each). Insets show EGFP + SkM (green, autofluorescence brown) or Cx43 immunostaining (red; nuclear Hoechst stain, blue), of engrafted Cx43-SkM (e, upper right). ( f ) Burst stimulation induces self-terminating VT in a representative EGFP-SkM transplanted mouse in vivo . ( g ) No VT is evoked in a representative Cx43-SkM transplanted mouse upon burst stimulation. ( f , g ) Top trace, surface ECG; bottom trace, atrial intracardiac lead; A, atrium; V, ventricle. ( h ) Statistics of VT incidence upon burst stimulation in vivo reveals prominent reduction of VT inducibility after engraftment of Cx43-SkM compared to EGFP-SkM (p < 0.01). Scale bars: b = 30 µm; c = 200 µm; d,e = 500 µm; d,e insets = 100 µm; e upper right inset = 10 µm.

Article Snippet: As reported before , a surface 6-lead ECG was recorded (PowerLab 16/30, LabChart 7, ADInstruments, Pty LTD, Australia), then the tip of a 2 French octapolar mouse-electrophysiological catheter (CIBER Mouse Electrophysiology Catheter, NuMED, USA) was inserted to the apex of the right ventricle via the right jugular vein.

Techniques: Transduction, Functional Assay, In Vitro, In Vivo, Control, Cell Culture, Staining, Expressing, Membrane, Transgenic Assay, Ex Vivo, Imaging, Immunostaining

Journal: Scientific Reports

Article Title: Overexpression of Cx43 in cells of the myocardial scar: Correction of post-infarct arrhythmias through heterotypic cell-cell coupling

doi: 10.1038/s41598-018-25147-8

Figure Lengend Snippet: Injection of lvCx43 into the myocardial scar strongly lowers post-infarct VT incidence in vivo at 2 weeks after gene therapy ; myocardial remodeling and left ventricular function remain unaltered. ( a – c ) In vivo electrophysiological testing. ( a ) Burst stimulation induces self-limiting VT with typical atrio-ventricular dissociation (lower panel) in a representative lvEGFP injected mouse (upper panel). ( b ) No VT is evoked in a representative lvCx43 transduced mouse upon burst stimulation. (a,b) Top trace, surface ECG; bottom trace, atrial intracardiac lead. ( c ) Magnification of traces shown in (b) reveals appropriate stimulation during the stimulation train, but no VT is induced; due to the short refractory period of murine ventricular myocardium a 3:1 capture during burst stimulation (S1S1 10–50 ms) is achieved. (a–c) A, atrium; V, ventricle. ( d ) In vivo VT incidence after transduction with lvCx43 is significantly reduced compared to lvEGFP injected control hearts (p < 0.02). ( e , f ) lvCx43 and lvEGFP injected hearts display very similar left ventricular function ( e ) and infarct size ( f ).

Article Snippet: As reported before , a surface 6-lead ECG was recorded (PowerLab 16/30, LabChart 7, ADInstruments, Pty LTD, Australia), then the tip of a 2 French octapolar mouse-electrophysiological catheter (CIBER Mouse Electrophysiology Catheter, NuMED, USA) was inserted to the apex of the right ventricle via the right jugular vein.

Techniques: Injection, In Vivo, Transduction, Control

Journal: Scientific Reports

Article Title: Overexpression of Cx43 in cells of the myocardial scar: Correction of post-infarct arrhythmias through heterotypic cell-cell coupling

doi: 10.1038/s41598-018-25147-8

Figure Lengend Snippet: Injection of lvCx43 into the myocardial scar increases conduction in Langendorff-perfused hearts and provides long time protection against VT in vivo . ( a – d ) Optical mapping ( a ) Overview of a representative lvEGFP injected heart (leftmost panel, infarct region is encircled). Under sinus rhythm and unipolar pacing from the base of the heart, sequential di-4-ANNEPS fluorescence images display highly irregular and atypical conduction paths surrounding the lesioned area (images every 11 ms). ( b ) Also lvCx43 injected hearts revealed atypical propagation patterns, but some conduction through the scar area is visible (images every 8 ms). ( c ) Isochronal maps (same hearts as in a and b) depicting the activation wavefront and conduction delays near the infarct border zone. The activation bypasses the lvEGFP injected infarct (upper panel), but propagates through the lesioned area in the lvCx43 injected heart (lower panel); H, healthy; B, border zone; I, infarct. Scale bar indicates local activation times. ( d ) Local conduction velocities at 200 ms pacing. Note its significant increase in the infarct area (p = 0.0173) of lvCx43 injected hearts (n = 5) vs lvEGFP injected control hearts (n = 5). ( e , f ) Representative traces during in vivo burst stimulation 2 months after lentiviral gene transfer recorded from a lvEGFP ( e ) and a lvCx43 ( f ) injected heart. In the lvEGFP heart onset of VT shortly upon burst stimulation is observed (e), whereas no VT is induced in the lvCx43 heart (f); Top trace, surface ECG; bottom trace, atrial intracardiac lead; A, atrium; V, ventricle. ( g ) Statistical analysis of VT incidence shows a significantly (p < 0.05) lower incidence in the lvCx43 compared to lvEGFP control hearts. ( h , i ) There is no difference in left ventricular function (fractional shortening, h ) and infarct size ( i ) between lvEGFP and lvCx43 injected hearts 8 weeks after gene therapy.

Article Snippet: As reported before , a surface 6-lead ECG was recorded (PowerLab 16/30, LabChart 7, ADInstruments, Pty LTD, Australia), then the tip of a 2 French octapolar mouse-electrophysiological catheter (CIBER Mouse Electrophysiology Catheter, NuMED, USA) was inserted to the apex of the right ventricle via the right jugular vein.

Techniques: Injection, In Vivo, Fluorescence, Activation Assay, Control

Journal: Scientific Reports

Article Title: Age-dependent transition from islet insulin hypersecretion to hyposecretion in mice with the long QT-syndrome loss-of-function mutation Kcnq1-A340V

doi: 10.1038/s41598-021-90452-8

Figure Lengend Snippet: Electrocardiograms during anaesthesia confirm longer QT interval. ( A – D) RR interval ( A ), PR interval ( B ), QRS duration ( C ) and QT interval ( D ) at baseline and after isoprenaline administration in WT (n = 9), HET (n = 9) and HOM (n = 8) mice. ( E ) QT (%) change from baseline. ( F ) Isoprenaline induced changes in T wave orientation in a subset of WT and HET mice and the majority of HOM mice 1 min after administration, which subsided 5 min after administration in the majority of cases. ( G) Representative traces five minutes after isoprenaline injection. The dashed lines indicate where QT was measured using the tangent approach. Note that in this HOM mouse, the T wave was not only prolonged, but also became positive, illustrating the T wave orientation changes of F . ( A – E) tested with two-way ANOVA with Dunnett’s multiple comparisons testing. *: WT versus HOM, P < 0.05, **: WT versus HOM, P < 0.01. ANOVA, analysis of variance; HET, heterozygous; HOM, homozygous; WT, wild-type.

Article Snippet: Subcutaneous needle electrodes were used to record a 6-lead surface electrocardiogram (ECG) at 4 kHz using LabChart 8 (ADInstruments, Australia).

Techniques: Injection

Journal: Scientific Reports

Article Title: Age-dependent transition from islet insulin hypersecretion to hyposecretion in mice with the long QT-syndrome loss-of-function mutation Kcnq1-A340V

doi: 10.1038/s41598-021-90452-8

Figure Lengend Snippet: Electrocardiogram telemetry during refeeding. WT (n = 8), HET (n = 7) and HOM (n = 4) mice were fasted overnight for 18 h, after which they were re-fed. ( A , B ) RR interval (A) and QT interval (B) dropped immediately upon refeeding. ( C ) RR/QT relationships were plotted and revealed a change after refeeding in HET and HOM mice, but not in WT mice. ( D ) During the first 30 min after refeeding, PVCs were counted, revealing an increased number of PVCs in HOM mice. ( E ) Representative ECG traces with PVCs in three different mice (PVCs indicated by arrowheads). Analyzed with Kruskal–Wallis test with Dunn's multiple comparisons testing. *: WT versus HOM, P < 0.05. HET, heterozygous; HOM, homozygous; PVC, premature ventricular contraction; WT, wild-type.

Article Snippet: Subcutaneous needle electrodes were used to record a 6-lead surface electrocardiogram (ECG) at 4 kHz using LabChart 8 (ADInstruments, Australia).

Techniques: