A Semi-automatic Approach for Segmentation of Three-Dimensional Microscopic Image Stacks of Cardiac Tissue

Seidel, Thomas; Draebing, Thomas; Seemann, Gunnar; Sachse, Frank B.

doi:10.1007/978-3-642-38899-6_36

Cited by 18 publications

(18 citation statements)

References 16 publications

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“…1). 27 We then determined eigenvectors and eigenvalues (|λ 1 |≥|λ 2 |≥|λ 3 |) 28 and calculated cross-section circularity, defined as ratio of the two minor eigenvalues |λ 3 /λ 2 |, utilizing a published algorithm based on gradient vector flow. 29 All t-system and RyR measures were first averaged per image and subsequently per sample, resulting in one numerical value per measure and patient used for statistical analysis.…”

Section: Methodsmentioning

confidence: 99%

Sheet-Like Remodeling of the Transverse Tubular System in Human Heart Failure Impairs Excitation-Contraction Coupling and Functional Recovery by Mechanical Unloading

et al. 2017

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Background Cardiac recovery in response to mechanical unloading by left ventricular assist devices (LVADs) has been demonstrated in subgroups of chronic heart failure (HF) patients. Hallmarks of HF are depletion and disorganization of the transverse tubular system (t-system) in cardiomyocytes. Here, we investigated remodeling of the t-system in human end-stage HF and its role in cardiac recovery. Methods Left ventricular biopsies were obtained from 5 donors (CTRL) and 26 chronic HF patients undergoing implantation of LVADs. Three-dimensional confocal microscopy and computational image analysis were applied to assess t-system structure, density, and distance of ryanodine receptor (RyR) clusters to the sarcolemma, including the t-system. Recovery of cardiac function in response to mechanical unloading was assessed by echocardiography during turn-down of the LVAD. Results The majority of HF myocytes showed remarkable t-system remodeling, particularly sheet-like invaginations of the sarcolemma. Circularity of t-system components was decreased in HF vs CTRL (0.37±0.01 vs 0.46±0.02, p<0.01), and the volume/length ratio was increased in HF (0.36±0.01μm2 vs 0.25±0.02μm2, p<0.0001). T-system density was reduced in HF, leading to increased RyR-sarcolemma distances (0.96±0.05μm vs 0.64±0.1μm, p<0.01). Low RyR-sarcolemma distances at time of LVAD implantation predicted high post-LVAD left-ventricular ejection fractions (EF, p<0.01) and EF increase during unloading (p<0.01). EF in patients with pre-LVAD RyR-sarcolemma distances larger than 1μm did not improve following mechanical unloading. Additionally, calcium transients were recorded in field-stimulated isolated human cardiomyocytes and analyzed with respect to local t-system density. Calcium release in HF myocytes was restricted to regions proximal to the sarcolemma. Local calcium upstroke was delayed (23.9±4.9ms vs 10.3±1.7ms, p<0.05) and more asynchronous (18.1ms±1.5ms vs 8.9±2.2ms, p<0.01) in HF cells with low t-system density versus cells with high t-system density. Conclusions The t-system in end-stage human HF presents a characteristic novel phenotype consisting of sheet-like invaginations of the sarcolemma. Our results suggest that the remodeled t-system impairs excitation-contraction coupling and functional recovery during chronic LVAD unloading. An intact t-system at time of LVAD implantation may constitute a precondition and predictor for functional cardiac recovery following mechanical unloading.

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Section: Methodsmentioning

confidence: 99%

Sheet-Like Remodeling of the Transverse Tubular System in Human Heart Failure Impairs Excitation-Contraction Coupling and Functional Recovery by Mechanical Unloading

et al. 2017

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“…The segmented WGA signal was used to segment each cardiomyocyte by means of a watershed-based method as described previously. 34 This method created labeled segments for each volume enclosed by WGA signal. At first, we identified myocytes.…”

Section: Methodsmentioning

confidence: 99%

Analyzing Remodeling of Cardiac Tissue: A Comprehensive Approach Based on Confocal Microscopy and 3D Reconstructions

2015

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Microstructural characterization of cardiac tissue and its remodeling in disease is a crucial step in many basic research projects. We present a comprehensive approach for three-dimensional characterization of cardiac tissue at the submicrometer scale. We developed a compression-free mounting method as well as labeling and imaging protocols that facilitate acquisition of three-dimensional image stacks with scanning confocal microscopy. We evaluated the approach with normal and infarcted ventricular tissue. We used the acquired image stacks for segmentation, quantitative analysis and visualization of important tissue components. In contrast to conventional mounting, compression-free mounting preserved cell shapes, capillary lumens and extracellular laminas. Furthermore, the new approach and imaging protocols resulted in high signal-to-noise ratios at depths up to 60 μm. This allowed extensive analyses revealing major differences in volume fractions and distribution of cardiomyocytes, blood vessels, fibroblasts, myofibroblasts and extracellular space in control versus infarct border zone. Our results show that the developed approach yields comprehensive data on microstructure of cardiac tissue and its remodeling in disease. In contrast to other approaches, it allows quantitative assessment of all major tissue components. Furthermore, we suggest that the approach will provide important data for physiological models of cardiac tissue at the submicrometer scale.

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“…The resulting image volumes (Fig. 6) can be utilized in functional models by applying appropriate segmentation techniques [24] to determine cell coupling patterns in normal WKY tissue and fibrotic SHR tissue. Healthy tissue has been shown to have an average of 11 myocytes connected to 1 myocyte [25].…”

Section: Discussionmentioning

confidence: 99%

“…We extend tools and techniques [11,12] that have previously been used to characterize 3D cardiac structure at a range of scales and outline their application to relating fibrosis to heart rhythm disturbance.…”

Section: Introductionmentioning

confidence: 99%

Quantifying Structural and Functional Differences Between Normal and Fibrotic Ventricles

Khwaounjoo

LeGrice

Trew

et al. 2015

Functional Imaging and Modeling of the Heart

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Abstract. Fibrosis is a significant component of cardiac remodeling in heart failure. However, such remodeling has not been fully quantified across a range of scales and the functional impacts on arrhythmogenesis are still poorly understood. Transmural ventricular tissue samples from WKY and SHR rats are imaged and analyzed structurally at the scale of myocardial laminae. New imaging protocols and immunohistochemical labeling are investigated for 3D reconstructions of cell distributions and interconnectivity. At larger scales, there are obvious structural differences between WKY and SHR tissue in fiber rotation and tissue connectivity. Electrical activation models show less significant differences in functional behavior between the two tissue types. Imaging extended volume 3D cell connectivity provides promising insights and will be used in the future to inform modeling at larger scales.

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A Semi-automatic Approach for Segmentation of Three-Dimensional Microscopic Image Stacks of Cardiac Tissue

Cited by 18 publications

References 16 publications

Sheet-Like Remodeling of the Transverse Tubular System in Human Heart Failure Impairs Excitation-Contraction Coupling and Functional Recovery by Mechanical Unloading

Sheet-Like Remodeling of the Transverse Tubular System in Human Heart Failure Impairs Excitation-Contraction Coupling and Functional Recovery by Mechanical Unloading

Analyzing Remodeling of Cardiac Tissue: A Comprehensive Approach Based on Confocal Microscopy and 3D Reconstructions

Quantifying Structural and Functional Differences Between Normal and Fibrotic Ventricles

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