We thank the individuals who have donated their bodies for the advancement of education and research. We are grateful to the OneLegacy Foundation, which formed the basis for obtaining donor hearts for research. We are also grateful to Anthony A. Smithson and Arvin Roque-Verdeflor of the UCLA Translational Research Imaging Center (Department of Radiology) for their support in CT data acquisition. This project was supported by the UCLA Amara Yad Project. We are thankful to Drs. Kalyanam Shivkumar and Olujimi A. Ajijola for establishing and maintaining a human heart pipeline for research. We appreciate our Research Operations Manager, Amiksha S. Gandhi for her dedication to support our projects. This work was made possible by support from NIH grants OT2OD023848 &#38; P01 HL164311 and Leducq grant 23CVD04 to Kalyanam Shivkumar, the American Heart Association Career Development Award 23CDA1039446 to PH, and the UCLA Amara-Yad Project (https://www.uclahealth.org/medical-services/heart/arrhythmia/about-us/amara-yad-project). The GNEXT microPET/CT scanner used in this study was funded by an NIH Shared Instrumentation for Animal Research Grant (1 S10 OD026917-01A1).

This study used de-identified tissue samples collected from non-failing donor human hearts and was approved by the Institutional Review Board of the University of California, Los Angeles (UCLA). Samples were obtained from non-failing hearts that were rejected for transplantation. The hearts were pressure-perfused, fixed in 4% paraformaldehyde (PFA), and imaged before tissue processing per the following methods. Figure 1 summarizes the flow chart of the order of the study. The details of the ...

Comprehensive 3D Analysis of Human Hearts from Micro to Macro Scales

<ol>
	<li>Tawara, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Das+reizleitungssystem+des+s&#228;ugetierherzens.+Eine+anatomisch-histologische+studie+&#252;ber+das+atrioventrikularb&#252;ndel+und+die+purkinjeschen+f&#228;den.">Das reizleitungssystem des s&#228;ugetierherzens. Eine anatomisch-histologische studie &#252;ber das atrioventrikularb&#252;ndel und die purkinjeschen f&#228;den.</a> Jena: Gustav fischer. , (1906).</li><li>Stephenson, R. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+3-dimensional+imaging+of+the+human+cardiac+conduction+system+from+microanatomy+to+mathematical+modeling.">High-resolution 3-dimensional imaging of the human cardiac conduction system from microanatomy to mathematical modeling.</a> Sci Rep. 7 (1), 7188 (2017).</li><li>Kawashima, T., Sato, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=First+in+situ+3D+visualization+of+the+human+cardiac+conduction+system+and+its+transformation+associated+with+heart+contour+and+inclination.">First in situ 3D visualization of the human cardiac conduction system and its transformation associated with heart contour and inclination.</a> Sci Rep. 11 (1), 8636 (2021).</li><li>Bojsen-Moller, F., Tranum-Jensen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-mount+demonstration+of+cholinesterase-containing+nerves+in+the+right+atrial+wall,+nodal+tissue,+and+atrioventricular+bundle+of+the+pig+heart.">Whole-mount demonstration of cholinesterase-containing nerves in the right atrial wall, nodal tissue, and atrioventricular bundle of the pig heart.</a> J Anat. 108, 375-386 (1971).</li><li>Zhao, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ganglionated+plexi+and+ligament+of+marshall+ablation+reduces+atrial+vulnerability+and+causes+stellate+ganglion+remodeling+in+ambulatory+dogs.">Ganglionated plexi and ligament of marshall ablation reduces atrial vulnerability and causes stellate ganglion remodeling in ambulatory dogs.</a> Heart Rhythm. 13 (10), 2083-2090 (2016).</li><li>Chung, W. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ischemia-induced+ventricular+proarrhythmia+and+cardiovascular+autonomic+dysreflexia+after+cardioneuroablation.">Ischemia-induced ventricular proarrhythmia and cardiovascular autonomic dysreflexia after cardioneuroablation.</a> Heart Rhythm. 20 (11), 1534-1545 (2023).</li><li>Crick, S. J., Sheppard, M. N., Ho, S. Y., Gebstein, L., Anderson, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy+of+the+pig+heart:+Comparisons+with+normal+human+cardiac+structure.">Anatomy of the pig heart: Comparisons with normal human cardiac structure.</a> J Anat. 193, 105-119 (1998).</li><li>Saburkina, I., Pauziene, N., Solomon, O. I., Rysevaite-Kyguoliene, K., Pauza, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+gross+anatomy+of+epicardiac+ganglionated+nerve+plexi+on+the+human+and+sheep+cardiac+ventricles.">Comparative gross anatomy of epicardiac ganglionated nerve plexi on the human and sheep cardiac ventricles.</a> Anat Rec (Hoboken). 306 (9), 2302-2312 (2023).</li><li>Hoagland, D. T., Santos, W., Poelzing, S., Gourdie, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+the+gap+junction+perinexus+in+cardiac+conduction:+Potential+as+a+novel+anti-arrhythmic+drug+target.">The role of the gap junction perinexus in cardiac conduction: Potential as a novel anti-arrhythmic drug target.</a> Prog Biophys Mol Biol. 144, 41-50 (2019).</li><li>Aksu, T., Gopinathannair, R., Gupta, D., Pauza, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intrinsic+cardiac+autonomic+nervous+system:+What+do+clinical+electrophysiologists+need+to+know+about+the+&amp;#34;heart+brain&amp;#34.">Intrinsic cardiac autonomic nervous system: What do clinical electrophysiologists need to know about the &amp;#34;heart brain&amp;#34.</a> J Cardiovasc Electrophysiol. 32 (6), 1737-1747 (2021).</li><li>Hanna, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Innervation+and+neuronal+control+of+the+mammalian+sinoatrial+node+a+comprehensive+atlas.">Innervation and neuronal control of the mammalian sinoatrial node a comprehensive atlas.</a> Circ Res. 128 (9), 1279-1296 (2021).</li><li>Rajendran, P. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+peripheral+neural+circuits+that+regulate+heart+rate+using+optogenetic+and+viral+vector+strategies.">Identification of peripheral neural circuits that regulate heart rate using optogenetic and viral vector strategies.</a> Nature Communications. 10, 1944 (2019).</li><li>Renier, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+of+brain+activity+by+automated+volume+analysis+of+immediate+early+genes.">Mapping of brain activity by automated volume analysis of immediate early genes.</a> Cell. 165 (7), 1789-1802 (2016).</li><li>Mcalpine, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+and+coronary+arteries:+An+anatomical+atlas+for+clinical+diagnosis,+radiological+investigation,+and+surgical+treatment.">Heart and coronary arteries: An anatomical atlas for clinical diagnosis, radiological investigation, and surgical treatment.</a> Springer-verlag. , (1975).</li><li>Mori, S., Shivkumar, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereoscopic+three-dimensional+anatomy+of+the+heart:+Another+legacy+of+dr.+Wallace+a.+Mcalpine.">Stereoscopic three-dimensional anatomy of the heart: Another legacy of dr. Wallace a. Mcalpine.</a> Anat Sci Int. 96 (3), 485-488 (2021).</li><li>Izawa, Y., Nishii, T., Mori, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereogram+of+the+living+heart,+lung,+and+adjacent+structures.">Stereogram of the living heart, lung, and adjacent structures.</a> Tomography. 8 (2), 824-841 (2022).</li><li>Sato, T., Hanna, P., Ajijola, O. A., Shivkumar, K., Mori, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photogrammetry+of+perfusion-fixed+heart:+Innovative+approach+to+study+3-dimensional+cardiac+anatomy.">Photogrammetry of perfusion-fixed heart: Innovative approach to study 3-dimensional cardiac anatomy.</a> JACC Case Rep. 21, 101937 (2023).</li><li>Tretter, J. T., Gupta, S. K., Izawa, Y., Nishii, T., Mori, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virtual+dissection:+Emerging+as+the+gold+standard+of+analyzing+living+heart+anatomy.">Virtual dissection: Emerging as the gold standard of analyzing living heart anatomy.</a> J Cardiovasc Dev Dis. 7 (3), 30 (2020).</li><li>Thomas, A. C., Davies, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+demonstration+of+cardiac+pathology+using+perfusion-fixation.">The demonstration of cardiac pathology using perfusion-fixation.</a> Histopathology. 9 (1), 5-19 (1985).</li><li>Glagov, S., Eckner, F. A., Lev, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+pressure+fixation+apparatus+for+hearts.">Controlled pressure fixation apparatus for hearts.</a> Arch Pathol. 76, 640-646 (1963).</li><li>Iaizzo, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+visible+heart(r)+project+and+free-access+website+'atlas+of+human+cardiac+anatomy.">The visible heart(r) project and free-access website 'atlas of human cardiac anatomy.</a> Europace. 18, 163-172 (2016).</li><li>Yang, Y., Huang, H., Li, L., Yang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiplex+immunohistochemistry+staining+for+paraffin-embedded+lung+cancer+tissue.">Multiplex immunohistochemistry staining for paraffin-embedded lung cancer tissue.</a> J Vis Exp. (201), e65850 (2023).</li><li>Tripathy, S., Das, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+for+organ+preservation:+Current+prospective+and+challenges.">Strategies for organ preservation: Current prospective and challenges.</a> Cell Biol Int. 47 (3), 520-538 (2023).</li><li>Mori, S., Shivkumar, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atlas+of+cardiac+anatomy+(anatomical+basis+of+cardiac+interventions.+Vol.+1).">Atlas of cardiac anatomy (anatomical basis of cardiac interventions. Vol. 1).</a> Cardiotext. , (2022).</li><li>Crosado, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenoxyethanol-based+embalming+for+anatomy+teaching:+An+18+years'+experience+with+crosado+embalming+at+the+university+of+otago+in+new+zealand.">Phenoxyethanol-based embalming for anatomy teaching: An 18 years' experience with crosado embalming at the university of otago in new zealand.</a> Anat Sci Educ. 13 (6), 778-793 (2020).</li><li>Titmus, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+workflow+for+the+creation+of+photorealistic+3d+cadaveric+models+using+photogrammetry.">A workflow for the creation of photorealistic 3d cadaveric models using photogrammetry.</a> J Anat. 243 (2), 319-333 (2023).</li><li>Silva, J. N. A., Southworth, M., Raptis, C., Silva, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+applications+of+virtual+reality+in+cardiovascular+medicine.">Emerging applications of virtual reality in cardiovascular medicine.</a> JACC Basic Transl Sci. 3 (3), 420-430 (2018).</li><li>Maresky, H. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Virtual+reality+and+cardiac+anatomy:+Exploring+immersive+three-dimensional+cardiac+imaging,+a+pilot+study+in+undergraduate+medical+anatomy+education.">Virtual reality and cardiac anatomy: Exploring immersive three-dimensional cardiac imaging, a pilot study in undergraduate medical anatomy education.</a> Clin Anat. 32 (2), 238-243 (2019).</li><li>Mori, S., Shivkumar, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real+three-dimensional+cardiac+imaging+using+leading-edge+holographic+display.">Real three-dimensional cardiac imaging using leading-edge holographic display.</a> Clin Anat. 34 (6), 966-968 (2021).</li></ol>

The present study demonstrates&#160;the comprehensive pipeline to analyze samples obtained from whole human hearts. Representative results show&#160;micro- to macroscale anatomical examinations carried out routinely for a single heart. As a&#160;human heart sample is extremely precious, a multi-scale approach is ideal and effective so as not to waste any parts of the sample by applying multiple&#160;protocols for various purposes, including discovery in scientific research, improvement of clinical procedures, and anatomi...

As function follows form, understanding the architecture of the heart is fundamental for appreciation of its physiology. Although numerous investigations have revealed cardiac anatomy from micro- to macroscales1,2,3, multiple questions remain unresolved, especially those related to human cardiac anatomy. This is in part because basic studies focusing on functional anatomy generally utilized animal hearts4,5,6, which are often distinct from human hearts1,7,8. Furthermore, each individual study, even those using human heart samples, tends to focus on very specific structures, which renders it difficult to apply the findings in the context of the whole heart. This is even more so if the focused structures are at micro- or mesoscales, such as the perinexus9 and ganglionated plexuses10.
In this context, systemic structural study of the human heart rejected for transplantation provides a unique and rare opportunity to obtain a comprehensive atlas of cardiac structures in focus across microscopic and macroscopic scales11. Microscopic examination protocols include tissue clearing (modified immunolabeling-enabled three-dimensional (3D) imaging of solvent-cleared organs, iDISCO+)12,13, and immunohistochemical staining. Mesoscopic examination protocols include stereoscopic dissection, macro photography, and micro-computed tomographic (CT) scanning. Macroscopic examination protocols include gross dissection14, photography (including anaglyphs and photogrammetry)15,16,17, CT, virtual dissection18, and 3D printing of the physically or virtually dissected or whole heart17. In preparation for&#160;macroscopic examination, pressure-perfusion fixation is&#160;performed to maintain the 3D architecture and physiologically relevant morphology of the heart14,19,20,21.&#160;The combined application of these techniques is unique and crucial to correlate distinct anatomic features in the context of the 3D architecture of the human heart.
As the opportunity to obtain a non-pathological human heart sample is extremely limited, a multi-scale approach described herein maximizes the use of the sample. By applying various procedures described below, representative results will illustrate to the reader how the findings can be utilized for multiple purposes, including discovery in scientific research11 (comprehensive analyses of cardiac innervation, distribution of ganglionated plexuses), improvement of clinical procedures (simulation for surgical and interventional approaches), and anatomical education (real 3D demonstration of cardiac anatomy).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1x Phosphate buffered saline</td>
			<td>Sigma-Aldrich</td>
			<td>P3813</td>
			<td></td>
		</tr>
		<tr>
			<td>3D Viewer</td>
			<td>Microsoft</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>647 AffiniPure Donkey Anti-Rabbit IgG</td>
			<td>Jackson ImmunoResearch Laboratories</td>
			<td>711-605-152</td>
			<td></td>
		</tr>
		<tr>
			<td>647 AffiniPure Donkey Anti-Sheep IgG</td>
			<td>Jackson ImmunoResearch Laboratories</td>
			<td>713-605-147</td>
			<td></td>
		</tr>
		<tr>
			<td>AF Micro-NIKKOR 200 mm f/4D IF-ED lens</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Actin, &#945;-Smooth Muscle - Cy3 antibody</td>
			<td>Sigma-Aldrich</td>
			<td>C6198</td>
			<td></td>
		</tr>
		<tr>
			<td>Antigen Retrieval Buffer (100x EDTA Buffer, pH 8.0)</td>
			<td>Abcam</td>
			<td>ab93680</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-PGP9.5 (protein gene product 9.5)</td>
			<td>Abcam</td>
			<td>ab108986</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-TH (tyrosine hydrox ylase)</td>
			<td>Abcam</td>
			<td>ab1542</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-VAChT (vesicular acetylcholine transporter)</td>
			<td>Synaptic Systems</td>
			<td>139 103</td>
			<td></td>
		</tr>
		<tr>
			<td>Benzyl ether</td>
			<td>Sigma-Aldrich</td>
			<td>108014</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A4503-10G</td>
			<td></td>
		</tr>
		<tr>
			<td>Cheetah 3D printer filament (95A), 1.75 mm</td>
			<td>NinjaTek</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Coverslip, 22 mm x 30mm, No. 1.5</td>
			<td>VWR</td>
			<td>48393 151</td>
			<td></td>
		</tr>
		<tr>
			<td>Cy3 AffiniPure Donkey Anti-Rabbit IgG</td>
			<td>Jackson ImmunoResearch Laboratories</td>
			<td>711-165-152</td>
			<td></td>
		</tr>
		<tr>
			<td>Dichloromethane</td>
			<td>Sigma-Aldrich</td>
			<td>270997-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide</td>
			<td>Sigma-Aldrich</td>
			<td>D8418-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol, 100%</td>
			<td>Decon laboratories</td>
			<td>2701</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Sigma-Aldrich</td>
			<td>G7126-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>GNEXT PET/CT</td>
			<td>SOFIE Biosciences</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin sodium salt from porcine intestinal mucosa</td>
			<td>Sigma-Aldrich</td>
			<td>H3149-50KU</td>
			<td></td>
		</tr>
		<tr>
			<td>Histodenz</td>
			<td>Sigma-Aldrich</td>
			<td>D2158-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen peroxide solution</td>
			<td>Sigma-Aldrich</td>
			<td>H1009-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Imaging software</td>
			<td>Zeiss</td>
			<td>ZEN (black edition)</td>
			<td></td>
		</tr>
		<tr>
			<td>Imaging software</td>
			<td>Oxford Instruments</td>
			<td>Imaris 10</td>
			<td></td>
		</tr>
		<tr>
			<td>iSpacer</td>
			<td>Sunjin Labs</td>
			<td>iSpacer 3mm</td>
			<td></td>
		</tr>
		<tr>
			<td>KIRI Engine</td>
			<td>KIRI Innovation</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Laser scanning confocal microscope</td>
			<td>Zeiss</td>
			<td>LSM 880</td>
			<td></td>
		</tr>
		<tr>
			<td>LEAD-2 - Vertical &#38; Multi-channels Peristaltic Pump</td>
			<td>LONGER</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Lightview XL&#160;</td>
			<td>Brightech</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol (Certified ACS)</td>
			<td>Fischer Scientific</td>
			<td>A412-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon D850</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NinjaTek NinjaFlex TPU @MK4</td>
			<td>NinjaTek</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Normal donkey serum</td>
			<td>Jackson ImmunoResearch Laboratories</td>
			<td>017-000-121</td>
			<td></td>
		</tr>
		<tr>
			<td>Original Prusa MK4 3D printer</td>
			<td>Prusa Research</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PAP pen</td>
			<td>Abcam</td>
			<td>ab2601</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde, 32%</td>
			<td>Electron Microscopy Sciences</td>
			<td>15714-S</td>
			<td></td>
		</tr>
		<tr>
			<td>Polycam</td>
			<td>Polycam</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Primary antibody</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PrusaSlicer 2.7.1</td>
			<td>Prusa Research</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SARA-Engine</td>
			<td>pita4 mobile LLC</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Scaniverse</td>
			<td>Niantic</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Secondary antibody</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SlowFade Gold Antiface Mountant</td>
			<td>Invitrogen</td>
			<td>S36936</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium azide, 5% (w/v)</td>
			<td>Ricca Chemical Company</td>
			<td>7144.8-32</td>
			<td></td>
		</tr>
		<tr>
			<td>SOMATOM Definition AS</td>
			<td>Siemens Healthcare</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Standard Field Surgi-Spec Telescopes,&#160;</td>
			<td>Designs for Vision</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stereomicroscope System SZ61</td>
			<td>OLYMPUS</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>StereoPhoto Maker</td>
			<td>Free ware developed by Masuji Suto</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Superfrost Plus Microscope Slides, Precleaned</td>
			<td>Fisher Scientific</td>
			<td>12-550-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>T8787-50ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween-20</td>
			<td>Sigma-Aldrich</td>
			<td>P9416-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>Sigma-Aldrich</td>
			<td>534056-4L</td>
			<td></td>
		</tr>
		<tr>
			<td>Ziostation2</td>
			<td>Ziosoft, AMIN</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

pipeline for multi-scale three-dimensional anatomic study of the human heart

Detailed study of non-failing human hearts rejected for transplantation provides a unique opportunity to perform structural analyses across microscopic and macroscopic scales. These techniques include tissue clearing (modified immunolabeling-enabled three-dimensional (3D) imaging of solvent-cleared organs) and immunohistochemical staining. Mesoscopic examination procedures include stereoscopic dissection and micro-computed tomographic (CT) scanning. Macroscopic examination procedures include gross dissection, photography (including anaglyphs and photogrammetry), CT, and 3D printing of the physically or virtually dissected or whole heart. Before macroscopic examination, pressure-perfusion fixation may be performed to maintain the 3D architecture and physiologically relevant morphology of the heart. The application of these techniques in combination to study the human heart is unique and crucial in understanding the relationship between distinct anatomic features such as coronary vasculature and myocardial innervation in the context of the 3D architecture of the heart. This protocol describes the methodologies in detail and includes representative results&#160;to illustrate progress in the research of human cardiac anatomy.

Author Spotlight: Advancing Human Cardiac Anatomy Through Multi-Scale Analysis of Hearts

Pipeline for Multi-Scale Three-Dimensional Anatomic Study of the Human Heart

Knowing cardiac anatomy is fundamental to understanding cardiac physiology. Studies of functional anatomy have spanned the micro to macro scales, but have largely used animal hearts. Systematic study of donor human hearts rejected for transplantation provides a unique opportunity to develop a comprehensive atlas that spans the microscopic to macroscopic scales.Through study of the human heart across different scales, we've demonstrated the exquisite innervation of the heart, identified cardiac anatomic structures to improve surgical and interventional approaches, and developed resources for anatomic education. The advantage of studying the human heart across different scales is that the detailed study of microscopic structures may be placed in the context of gross anatomy. The use of pressure profusion fixation maintains the physiologically relevant morphology of the heart.

Microscale examinations 
Applying tissue clearing allows imaging of larger volumes of tissue in 3D using confocal microscopy. In the heart, ganglia containing cardiac neurons and the neural patterning of myocardial innervation can be visualized (Figure 2). Figure 3 shows a confocal image of the human left ventricle myocardium immunostained for nerves and smooth muscle cells. Blood vessels are noted to traverse the myocardium, and numerous n...

This protocol presents a comprehensive pipeline to analyze samples obtained from human hearts that span the microscopic and macroscopic scales.

Detailed study of non-failing human hearts rejected for transplantation provides a unique opportunity to perform structural analyses across microscopic ...

pipeline-for-multi-scale-three-dimensional-anatomic-study-human