This work is supported, in parts, by the National Institutes of Health grants HL-113281 and HL116205 to Paras Kumar Mishra.

The housing, anesthesia, and sacrifice of mice were performed following the approved IACUC protocol of the University of Nebraska Medical Center.
1. Materials
<ol>
	<li>Use 10- to 12-week-old C57BL/6J black male mice, kept in-house at the institutional animal facility, for the isolation of CSCs. CSCs can also be isolated from non-pregnant female mice.</li>
	<li>Sterilize all the necessary surgical instruments, including surgical scissors, fine surgical scissors, curved shank forceps, and a surgical blade, by autoclaving them before the euthanasia of the mouse.</li>
	<li>Prepare CSC isolation buffers in a sterilized condition and store them at 4 &#176;C on ice. These buffers include polysucrose and a sodium diatrizoate solution adjusted to a density of 1.077 g/mL, incomplete Dulbecco&#8217;s modified Eagle&#8217;s Medium, 1x Ham&#8217;s balanced salt solution (HBSS), and cell culture-grade 1x phosphate-buffered saline (PBS). Prepare a 1% collagenase II stock solution (filtered and sterilized) and a 0.2% working solution in HBSS.</li>
	<li>Keep the tissue culture materials in the sterilized condition in the biosafety cabinet, including a 10-mm Petri dish, a 6-well plate, a 24-well plate, T-25 and T-75 culture flasks, 15-mL and 50-mL conical tubes, and disposable serological pipettes with 40-&#181;m and 100-&#181;m cell strainers with 0.22-&#181;m filters.</li>
	<li>Sterilize the 10-&#181;L, 200-&#181;L, and 1,000-&#181;L pipette tips by autoclave.</li>
	<li>Use powder-free nitrile gloves and 70% ethanol to maintain a sterile condition throughout the experiment.</li>
	<li>Use 10% bleach as a disinfectant.</li>
	<li>Use commercially available CSC maintenance medium and cardiomyocytes differentiation medium for the culture and differentiation of CSCs, respectively.</li>
</ol>
2. Isolation Method of Cardiac Stem Cells
<ol>
	<li>Euthanize four to five adult male (or non-pregnant female) mice using a CO2 chamber. Fix each mouse&#8217;s arms on a separate dissection cardboard with pins or sticky tapes.</li>
	<li>Spray 70% ethanol on the mouse to get rid of outside germs and maintain the sterilized condition during the harvesting of the heart. Make an incision with scissors in the middle of the abdomen and cut the skin from the abdomen up to the thorax in a straight line. Remove the skin from both sides of the middle cut to clear the abdominal area of skin and hairs. Using scissors and tweezers, cut the diaphragm below the ribcage.</li>
	<li>Open the thoracic cavity of the mouse by cutting the ribcage inside the hood. Expose the heart and remove the blood near the heart. Wash the surrounding area of the heart with ice-cold PBS to get rid of any blood in the vicinity of the heart.</li>
	<li>Dissect the heart using surgical scissors and tweezers. Place the heart in a 100-mm Petri dish containing 10 mL of ice-cold PBS.</li>
	<li>Palpitate the heart using curved shank forceps and remove the residual blood inside the heart.</li>
	<li>Use the whole heart for the isolation of CSCs.</li>
	<li>Transfer all four or five whole hearts to a 50-mL conical tube containing 10 mL of ice-cold HBSS. Keep the tube on ice until further processing.</li>
	<li>Wipe inside and outside of a biosafety cabinet with 70% ethanol to create a sterilized environment. Sterilize the heart-containing tube and other required materials with 70% ethanol. Place the heart-containing tube into the biosafety cabinet for further processing.</li>
	<li>Transfer the hearts to a 100-mm Petri dish containing 10 mL of ice-cold HBSS. Wash the hearts again by palpating to remove any residual blood inside the heart. Change the HBSS solution after each wash to ensure the complete removal of the blood.</li>
	<li>Cut the hearts into small pieces using fine surgical scissors or a surgical blade in a 100-mm Petri dish containing 5 - 7 mL of HBSS solution. Hold each heart with a pair of forceps and use a pair of surgical fine scissors or a surgical blade to cut the heart into 2- to 4-mm pieces. Change the HBSS solution frequently to ensure blood-free HBSS. Mince the hearts in the HBSS solution.</li>
	<li>Centrifuge the minced tissue at 500 x g at 4 &#176;C for 5 min. Discard the supernatant and keep the pellet.</li>
	<li>Resuspend the pellet in 5 - 6 mL of 0.2% collagenase II solution in a 50-mL conical tube. The volume of collagenase solution should be almost 1.5- to 2-fold to the volume of the pellet. 
	Note: For the digestion of tissue, 0.2% collagenase I and 2.5 U/mL dispase solution can replace 0.2% collagenase II. Use an almost equal volume of dispase solution to the collagenase I solution.</li>
	<li>Thoroughly mix the pellet with 0.2% collagenase II solution by agitating the tube or by rocking the tube on a shaker at 75 x g for 45 - 60 min at 37 &#176;C. Shake the tube vigorously by hand after every 20 - 30 min to enhance the lysis.</li>
	<li>Triturate the lysed tissue mix using&#160;a 5 mL serological pipette and a 1-mL pipette tip to dissociate the tissue lump into the single-cell suspension. 
	Note: To get the maximum recovery of the CSCs, triturate the lysis mix for at least 5 min. If the tissue lumps are relatively big, cut the tip of a 1-mL pipette tip with scissors or a surgical blade and use it for trituration.</li>
	<li>Stop the enzymatic lysis of the tissue by adding commercially available CSC maintenance medium. Add almost 2 - 3x as much maintenance medium as the volume of the lysed tissue in step 2.14.</li>
	<li>Pass the digested cell suspension through a 100-&#181;m cell strainer to remove any undigested tissue pieces.</li>
	<li>Repeat step 2.16 using a 40-&#181;m cell strainer.</li>
	<li>Separate the cells through density gradient centrifugation. For the separation of cells, gently overlay an equal volume of the filtrate over polysucrose and sodium diatrizoate solution. For example, first, add 20 mL of polysucrose and sodium diatrizoate solution in a 50-mL conical tube and then, add 20 mL of filtrate from step 2.17 over the polysucrose and sodium diatrizoate solution. 
	NOTE: Prewarm the polysucrose and sodium diatrizoate solution at 37 &#176;C before use with the cells. Add the filtrate from step 2.17 over the polysucrose and sodium diatrizoate solution very carefully and slowly to avoid any mixing of the two solutions. This is considered to be a crucial step.</li>
	<li>Centrifuge the tube containing both solutions at 500 x g for 20 min at room temperature using a swing bucket centrifuge. Set the centrifuge at a lower acceleration and deceleration speed to avoid mixing the two solutions and for proper separation of the CSCs. This is an important step in CSC isolation. Put the tube containing the gradient mixture very slowly without disturbance inside the centrifuge and set it for centrifugation.</li>
	<li>Take out the buffy coat along with extra solution from the upper layer using either a 1-mL pipette or a plastic Pasteur pipette in a 15-mL sterilized tube. This buffy layer will contain the CSCs. 
	Note: Take extra precaution during the pipetting of the buffy coat not to take out the polysucrose and sodium diatrizoate solution layer because it is toxic to CSCs.</li>
	<li>Add an equal volume of CSC maintenance medium to the cell suspension from step 2.20 and mix it properly to neutralize the residual polysucrose and sodium diatrizoate solution, if present.</li>
	<li>Centrifuge the above cell suspension at 500 x g for 5 min at 4 &#176;C. Discard the supernatant.</li>
	<li>Resuspend the pellet in 7 - 10 mL of incomplete DMEM medium and centrifuge it at 500 x g for 5 min at 4 &#176;C to get rid of any residual polysucrose and sodium diatrizoate solution.</li>
	<li>Collect the pellet, which contains the purified CSCs.</li>
	<li>Resuspend the pellet in 1 mL of CSC maintenance medium, count the CSC number, and use the pellet for culture. To count the CSC number, use Trypan blue staining and a hemocytometer. With four male mice hearts, the yield of CSCs is ~1.8 million.</li>
	<li>Seed the CSCs in a 6-well culture plate coated with a 0.02% gelatin solution containing 0.5% fibronectin. Use 2 mL of complete maintenance medium for seeding. Incubate the culture plate in an incubator at 37 &#176;C with 5% CO2.</li>
	<li>Replace the medium of culture CSCs with complete CSC maintenance medium every day until the third day. After that, change the medium on alternate days.</li>
	<li>Determine the growth of the CSCs by observing them under a microscope.</li>
</ol>
3. Culture Maintenance and Passage of Cardiac Stem Cells
<ol>
	<li>Culture the isolated CSCs in a commercially available maintenance medium. Replace the culture medium with fresh maintenance medium on alternate days. When the CSC culture has reached confluency, transfer the CSCs to a new plate coated with gelatin and fibronectin, as mentioned in step 2.26. Detach the cultured CSCs by enzymatic cell dissociation buffer. Follow the standard protocol of cell dissociation from the culture plate. At this stage, CSCs are considered at passage 0 (P0) stage.</li>
	<li>Culture P0 CSCs in a new gelatin and fibronectin-coated plate in complete CSC maintenance medium at 37 &#176;C in a 5% CO2 incubator, allow them to be confluent, and then follow step 3.1 to get passage 1 (P1) CSCs. Store P1 CSCs in liquid nitrogen or use them for experiments.</li>
	<li>Seed 0.5 million cells in a 6-well plate or 1 million cells in T-25 to maintain the CSC culture at its initial stage.</li>
	<li>Passage the CSCs when they become 85% - 90% confluent. CSCs can be cultured in the maintenance medium up to four to six weeks. 
	Note: Keep the initial seeding density of the CSCs relatively high (40% - 50%) because, at a lower seeding density, the CSCs may change their morphology to flat and elongated.</li>
</ol>
4. Characterization of Cardiac Stem Cells
<ol>
	<li>To characterize the cultured CSCs, observe them under a phage-contrast or a bright-field microscope. Place the CSC-containing plate on the objective of a fluorescent microscope. Set the magnification fairly low (10X) to focus the cells. Use phase-contrast aperture to observe the cells. Increase the magnification to 20X by changing the objective lens and image the CSCs. Increase the objective to 40X and image the CSCs. In two days, the CSCs appear almost round in shape, but the size of the cell increases with time, and in seven days, the CSCs appear almost cylindrical in shape (Figure&#160;1A - 1C).</li>
	<li>Perform immunostaining of the CSCs with markers of pluripotency/stemness (OCT4, SOX2, or Nanog), proliferation (Ki-67) (Figure&#160;2A - 2D), and cardiac origin/progenitor cells (Sca-1, NKX2-5, or GATA4) (Figure&#160;3A - 3C).
	<ol>
		<li>For the immunostaining of the CSCs, seed 10,000 CSCs in a 24-well culture plate.</li>
		<li>The next day (after 18 - 24 h), fix the CSCs in 300 &#181;L of 4% paraformaldehyde for 10 min.</li>
		<li>Wash the CSCs with 500 &#181;L of ice-cold PBS, 3x with 5-min intervals.</li>
		<li>Permeabilize the CSCs with 300 &#181;L of 0.2% Triton X-100 diluted in PBS for 10 min.</li>
		<li>Wash the CSCs with 500 &#181;L of ice-cold PBS, 3x with 5-min intervals.</li>
		<li>Perform the blocking of the CSCs with 300 &#181;L of 1% BSA diluted in PBST (PBS + 0.1% Tween 20) or 300 &#181;L of 10% normal chicken serum diluted in PBST for 1 h.</li>
		<li>Incubate the CSCs in 200 &#181;L of primary antibody diluted in blocking solution overnight at 4 &#176;C. Dilute the primary antibody as recommended by the datasheet of antibodies or as per standardization.</li>
		<li>Wash the CSCs with 500 &#181;L of ice-cold PBS, 3x with 5-min intervals.</li>
		<li>Incubate the CSCs in 200 &#181;L of secondary antibody diluted in blocking solution (see step 4.2.6) for 1 h at room temperature. Dilute the secondary antibody as recommended by the datasheet of antibodies or as per standardization.</li>
		<li>Wash the CSCs with 500 &#181;L of ice-cold PBS, 3x with 5-min intervals.</li>
		<li>Counterstain the CSCs with 200 &#181;L of DAPI (1 &#181;g/mL) diluted in PBS for 5 min.</li>
		<li>Wash the CSCs 1x with 500 &#181;L of ice-cold PBS. Then, add 300 &#181;L of ice-cold PBS in each well.</li>
		<li>Perform imaging using a fluorescence microscope. Follow the instructions of fluorescent imaging, such as to avoid direct light on the plate. Keep the culture plate under the microscope. Focus the cells at different magnifications. Observe the cells under phase-contrast and/or different excitation filters and save the images.</li>
		<li>Store the plate in the dark at 4 &#176;C.</li>
	</ol>
	</li>
</ol>
5. Differentiation of Cardiac Stem Cells into Cardiomyocyte
<ol>
	<li>For the differentiation of CSCs, seed 500,000 CSCs in a 6-well plate with 2&#160;mL of prewarm (37 &#176;C) commercially available CSC maintenance medium.</li>
	<li>Incubate the plate containing the CSCs in a CO2 incubator at 37 &#176;C. Allow the CSCs to attach and proliferate until sub-confluent growth. If the medium turns yellow, replace the culture medium with fresh maintenance medium.</li>
	<li>At 85% - 90% confluency, replace the maintenance medium with 2 mL of prewarm (37 &#176;C) cardiomyocytes differentiation medium. Incubate the plate in a CO2 incubator at 37 &#176;C for up to 2 - 3 weeks.</li>
	<li>Change the differentiation medium every 2 - 3 d. Observe the CSCs&#8217; morphology under a microscope every time during the medium change to ensure the good culture conditions.</li>
	<li>After 12 d of CSC culture in differentiation medium, image the CSCs for differentiation markers following a standard immunostaining protocol (see steps 4.2.1 - 4.2.14). Save the fluorescent images for the expression of cardiomyocytes markers (Figure&#160;4A - 4B).</li>
</ol>

<ol>
	<li>Benjamin, E. J., 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=Heart+Disease+and+Stroke+Statistics-2017+Update:+A+Report+From+the+American+Heart+Association.">Heart Disease and Stroke Statistics-2017 Update: A Report From the American Heart Association.</a> Circulation. 135, e146 (2017).</li><li>Nguyen, P. K., Rhee, J. W., Wu, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adult+Stem+Cell+Therapy+and+Heart+Failure,+2000+to+2016:+A+Systematic+Review.">Adult Stem Cell Therapy and Heart Failure, 2000 to 2016: A Systematic Review.</a> The Journal of the American Medical Association Cardiology. 1, 831-841 (2000).</li><li>Emmert, M. 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=Safety+and+efficacy+of+cardiopoietic+stem+cells+in+the+treatment+of+post-infarction+left-ventricular+dysfunction+-+From+cardioprotection+to+functional+repair+in+a+translational+pig+infarction+model.">Safety and efficacy of cardiopoietic stem cells in the treatment of post-infarction left-ventricular dysfunction - From cardioprotection to functional repair in a translational pig infarction model.</a> Biomaterials. 122, 48-62 (2017).</li><li>Silvestre, J. S., Menasche, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Evolution+of+the+Stem+Cell+Theory+for+Heart+Failure.">The Evolution of the Stem Cell Theory for Heart Failure.</a> EBioMedicine. 2, 1871-1879 (2015).</li><li>Terzic, A., Behfar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+cell+therapy+for+heart+failure:+Ensuring+regenerative+proficiency.">Stem cell therapy for heart failure: Ensuring regenerative proficiency.</a> Trends in Cardiovascular Medicine. 26, 395-404 (2016).</li><li>Yamada, 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=Embryonic+stem+cell+therapy+of+heart+failure+in+genetic+cardiomyopathy.">Embryonic stem cell therapy of heart failure in genetic cardiomyopathy.</a> Stem Cells. 26, 2644-2653 (2008).</li><li>Sadek, H. A., Martin, C. M., Latif, S. S., Garry, M. G., Garry, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone-marrow-derived+side+population+cells+for+myocardial+regeneration.">Bone-marrow-derived side population cells for myocardial regeneration.</a> Journal of Cardiovascular Translational Research. 2, 173-181 (2009).</li><li>Vrtovec, 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=Effects+of+intracoronary+CD34++stem+cell+transplantation+in+nonischemic+dilated+cardiomyopathy+patients:+5-year+follow-up.">Effects of intracoronary CD34+ stem cell transplantation in nonischemic dilated cardiomyopathy patients: 5-year follow-up.</a> Circulation Research. 112, 165-173 (2013).</li><li>Hare, J. 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=Comparison+of+allogeneic+vs+autologous+bone+marrow-derived+mesenchymal+stem+cells+delivered+by+transendocardial+injection+in+patients+with+ischemic+cardiomyopathy:+the+POSEIDON+randomized+trial.">Comparison of allogeneic vs autologous bone marrow-derived mesenchymal stem cells delivered by transendocardial injection in patients with ischemic cardiomyopathy: the POSEIDON randomized trial.</a> The Journal of American Medical Association. 308, 2369-2379 (2012).</li><li>Guijarro, D., 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=Intramyocardial+transplantation+of+mesenchymal+stromal+cells+for+chonic+myocardial+ischemia+and+impaired+left+ventricular+function:+Results+of+the+MESAMI+1+pilot+trial.">Intramyocardial transplantation of mesenchymal stromal cells for chonic myocardial ischemia and impaired left ventricular function: Results of the MESAMI 1 pilot trial.</a> International Journal of Cardiology. 209, 258-265 (2016).</li><li>Bobi, J., 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=Intracoronary+Administration+of+Allogeneic+Adipose+Tissue-Derived+Mesenchymal+Stem+Cells+Improves+Myocardial+Perfusion+But+Not+Left+Ventricle+Function,+in+a+Translational+Model+of+Acute+Myocardial+Infarction.">Intracoronary Administration of Allogeneic Adipose Tissue-Derived Mesenchymal Stem Cells Improves Myocardial Perfusion But Not Left Ventricle Function, in a Translational Model of Acute Myocardial Infarction.</a> Journal of the American Heart Association. 6, (2017).</li><li>Suzuki, E., Fujita, D., Takahashi, M., Oba, S., Nishimatsu, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue-derived+stem+cells+as+a+therapeutic+tool+for+cardiovascular+disease.">Adipose tissue-derived stem cells as a therapeutic tool for cardiovascular disease.</a> World Journal of Cardiology. 7, 454-465 (2015).</li><li>Gao, L. R., 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=Intracoronary+infusion+of+Wharton's+jelly-derived+mesenchymal+stem+cells+in+acute+myocardial+infarction:+double-blind,+randomized+controlled+trial.">Intracoronary infusion of Wharton's jelly-derived mesenchymal stem cells in acute myocardial infarction: double-blind, randomized controlled trial.</a> BMC Medicine. 13, 162 (2015).</li><li>Simpson, D. L., 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+strong+regenerative+ability+of+cardiac+stem+cells+derived+from+neonatal+hearts.">A strong regenerative ability of cardiac stem cells derived from neonatal hearts.</a> Circulation. , S46-S53 (2012).</li><li>Kazakov, A., 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=C-kit(+)+resident+cardiac+stem+cells+improve+left+ventricular+fibrosis+in+pressure+overload.">C-kit(+) resident cardiac stem cells improve left ventricular fibrosis in pressure overload.</a> Stem Cell Research. 15, 700-711 (2015).</li><li>Ong, S. G., 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=Cross+talk+of+combined+gene+and+cell+therapy+in+ischemic+heart+disease:+role+of+exosomal+microRNA+transfer.">Cross talk of combined gene and cell therapy in ischemic heart disease: role of exosomal microRNA transfer.</a> Circulation. 130, S60-S69 (2014).</li><li>Sahoo, S., Losordo, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exosomes+and+cardiac+repair+after+myocardial+infarction.">Exosomes and cardiac repair after myocardial infarction.</a> Circulation Research. 114, 333-344 (2014).</li><li>Zhang, Z., 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=Pretreatment+of+Cardiac+Stem+Cells+With+Exosomes+Derived+From+Mesenchymal+Stem+Cells+Enhances+Myocardial+Repair.">Pretreatment of Cardiac Stem Cells With Exosomes Derived From Mesenchymal Stem Cells Enhances Myocardial Repair.</a> Journal of the American Heart Association. 5, (2016).</li><li>Ibrahim, A. G., Cheng, K., Marban, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exosomes+as+critical+agents+of+cardiac+regeneration+triggered+by+cell+therapy.">Exosomes as critical agents of cardiac regeneration triggered by cell therapy.</a> Stem Cell Reports. 2, 606-619 (2014).</li><li>Emanueli, C., Shearn, A. I., Angelini, G. D., Sahoo, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exosomes+and+exosomal+miRNAs+in+cardiovascular+protection+and+repair.">Exosomes and exosomal miRNAs in cardiovascular protection and repair.</a> Vascular Pharmacology. 71, 24-30 (2015).</li><li>Menasche, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+cell+therapy:+lessons+from+clinical+trials.">Cardiac cell therapy: lessons from clinical trials.</a> Journal of Molecular and Cellular Cardiology. 50, 258-265 (2011).</li><li>Trounson, A., McDonald, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+Cell+Therapies+in+Clinical+Trials:+Progress+and+Challenges.">Stem Cell Therapies in Clinical Trials: Progress and Challenges.</a> Cell Stem Cell. 17, 11-22 (2015).</li><li>Takamiya, M., Haider, K. H., Ashaf, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+and+characterization+of+a+novel+multipotent+sub-population+of+Sca-1(+)+cardiac+progenitor+cells+for+myocardial+regeneration.">Identification and characterization of a novel multipotent sub-population of Sca-1(+) cardiac progenitor cells for myocardial regeneration.</a> PLoS One. 6, e25265 (2011).</li><li>Cambria, E., 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=Translational+cardiac+stem+cell+therapy:+advancing+from+first-generation+to+next-generation+cell+types.">Translational cardiac stem cell therapy: advancing from first-generation to next-generation cell types.</a> NPJ Regenerative Medicine. 2, 17 (2017).</li><li>Bruyneel, A. A., Sehgal, A., Malandraki-Miller, S., Carr, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+Cell+Therapy+for+the+Heart:+Blind+Alley+or+Magic+Bullet?.">Stem Cell Therapy for the Heart: Blind Alley or Magic Bullet?.</a> Journal of Cardiovascular Translational Research. 9, 405-418 (2016).</li><li>Garbern, J. C., Lee, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+stem+cell+therapy+and+the+promise+of+heart+regeneration.">Cardiac stem cell therapy and the promise of heart regeneration.</a> Cell Stem Cell. 12, 689-698 (2013).</li><li>Oh, H., Ito, H., Sano, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+to+success+in+heart+failure:+Cardiac+cell+therapies+in+patients+with+heart+diseases.">Challenges to success in heart failure: Cardiac cell therapies in patients with heart diseases.</a> Journal of Cardiology. 68, 361-367 (2016).</li><li>Smith, A. J., 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=Isolation+and+characterization+of+resident+endogenous+c-Kit++cardiac+stem+cells+from+the+adult+mouse+and+rat+heart.">Isolation and characterization of resident endogenous c-Kit+ cardiac stem cells from the adult mouse and rat heart.</a> Nature Protocols. 9, 1662-1681 (2014).</li><li>Rutering, J., 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=Improved+Method+for+Isolation+of+Neonatal+Rat+Cardiomyocytes+with+Increased+Yield+of+C-Kit++Cardiac+Progenitor+Cells.">Improved Method for Isolation of Neonatal Rat Cardiomyocytes with Increased Yield of C-Kit+ Cardiac Progenitor Cells.</a> Journal of Stem Cell Research and Therapy. 5, 1-8 (2015).</li><li>Saravanakumar, M., Devaraj, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distribution+and+homing+pattern+of+c-kit++Sca-1++CXCR4++resident+cardiac+stem+cells+in+neonatal,+postnatal,+and+adult+mouse+heart.">Distribution and homing pattern of c-kit+ Sca-1+ CXCR4+ resident cardiac stem cells in neonatal, postnatal, and adult mouse heart.</a> Cardiovascular Pathology. 22, 257-263 (2013).</li><li>Monsanto, M. 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=Concurrent+Isolation+of+3+Distinct+Cardiac+Stem+Cell+Populations+From+a+Single+Human+Heart+Biopsy.">Concurrent Isolation of 3 Distinct Cardiac Stem Cell Populations From a Single Human Heart Biopsy.</a> Circulation Research. 121, 113-124 (2017).</li><li>Vidyasekar, P., Shyamsunder, P., Santhakumar, R., Arun, R., Verma, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simplified+protocol+for+the+isolation+and+culture+of+cardiomyocytes+and+progenitor+cells+from+neonatal+mouse+ventricles.">A simplified protocol for the isolation and culture of cardiomyocytes and progenitor cells from neonatal mouse ventricles.</a> European Journal of Cell Biology. 94, 444-452 (2015).</li><li>Dergilev, K. V., 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=Comparison+of+cardiac+stem+cell+sheets+detached+by+Versene+solution+and+from+thermoresponsive+dishes+reveals+similar+properties+of+constructs.">Comparison of cardiac stem cell sheets detached by Versene solution and from thermoresponsive dishes reveals similar properties of constructs.</a> Tissue Cell. 49, 64-71 (2017).</li><li>Zaruba, M. M., Soonpaa, M., Reuter, S., Field, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiomyogenic+potential+of+C-kit(+)-expressing+cells+derived+from+neonatal+and+adult+mouse+hearts.">Cardiomyogenic potential of C-kit(+)-expressing cells derived from neonatal and adult mouse hearts.</a> Circulation. 121, 1992-2000 (1992).</li><li>Wang, 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=Isolation+and+characterization+of+a+Sca-1+/CD31-+progenitor+cell+lineage+derived+from+mouse+heart+tissue.">Isolation and characterization of a Sca-1+/CD31- progenitor cell lineage derived from mouse heart tissue.</a> BMC Biotechnology. 14, 75 (2014).</li><li>Smits, A. 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=Human+cardiomyocyte+progenitor+cells+differentiate+into+functional+mature+cardiomyocytes:+an+in+vitro+model+for+studying+human+cardiac+physiology+and+pathophysiology.">Human cardiomyocyte progenitor cells differentiate into functional mature cardiomyocytes: an in vitro model for studying human cardiac physiology and pathophysiology.</a> Nature Protocols. 4, 232-243 (2009).</li></ol>

The authors have nothing to disclose.

The critical steps of this CSC isolation protocol are as follows. 1) A sterilized condition must be maintained for extraction of the hearts from the mice. Any contamination during the heart extraction may compromise the quality of the CSCs. 2) The blood must be completely removed before mincing the heart, which is done by several washes of the whole heart and the heart pieces with HBSS solution. 3) The heart pieces must be completely lysed into a single-cell suspension with collagenase solution. 4) The polysucrose and so...

Ischemic heart disease, including myocardial infarction (MI), is a major cause of death around the world1. Stem cell therapy for regenerating dead myocardium remains a major approach to improve the cardiac function of an MI heart2,3,4,5. Different types of stem cells have been used to replenish dead myocardium and to improve the cardiac function of an MI heart. They can be broadly categorized into embryonic stem cells6 and adult stem cells. In adult stem cells, various types of stem cells have been used, such as bone marrow-derived mononuclear cells7,8, mesenchymal stem cells derived from bone marrow9,10, adipose tissue11,12, and umbilical cord13, and CSCs14,15. Stem cells can promote cardiac regeneration through endocrine and/or paracrine actions16,17,18,19,20. However, a major limitation of stem cell therapy is obtaining an adequate number of stem cells that can proliferate and/or differentiate toward a specific cardiac lineage21,22. Autologous and allogenic transplantation of stem cells is an important challenge in stem cell therapy9. CSCs could be a better approach for cardiac regeneration because they are derived from the heart and they can be more easily differentiated into cardiac lineages than non-cardiac stem cells. Thus, it reduces the risk of teratoma. In addition, the endocrine and paracrine effects of CSCs, such as exosomes and miRNAs derived from the CSCs, could be more effective than other types of stem cells. Thus, CSCs remains a better option for cardiac regeneration23,24.
Although CSCs are a better candidate for cardiac regeneration in an MI heart due to their cardiac origin, a major limitation with CSCs is less yield due to the lack of an efficient isolation method. Another limitation could be the impaired differentiation of CSCs toward cardiomyocytes lineage2,25,26,27. To circumvent these limitations, it is important to develop an efficient protocol for CSC isolation, characterization, and differentiation towards cardiac lineage. There is no single acceptable marker for CSCs and a specific cell-surface marker-based isolation of CSCs yields less CSCs. Here, we standardize a simple gradient centrifugation approach to isolate CSCs from the mouse heart that is cost-effective and results in an increased yield of CSCs. These isolated CSCs can be selected for specific cell-surface markers by fluorescence-activated cell shorting. In addition to CSCs isolation, we provided a protocol for CSC culture, characterization, and differentiation towards cardiomyocyte lineage. Thus, we present an elegant method to isolate, characterize, culture, and differentiate CSCs from adult mouse hearts (Figure 5).

<table><tbody><tr><td>&lt;strong&gt;Mice&lt;/strong&gt;</td><td>The Jackson laboratory, USA</td><td>Stock no. 000664</td><td></td></tr><tr><td>&lt;strong&gt;Antibodies:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>OCT4-</td><td>Abcam</td><td>ab18976 (rabbit polyclonal)</td><td>OCT4-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>SOX2</td><td>Abcam</td><td>ab97959 (rabbit polyclonal)</td><td>SOX2-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>Nanog</td><td>Abcam</td><td>ab80892 (rabbit polyclonal)</td><td>Nanog-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>Ki67</td><td>Abcam</td><td>ab16667 (rabbit polyclonal)</td><td>Ki67-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>Sca I</td><td>Millipore</td><td>AB4336 (rabbit polyclonal)</td><td>Sca I Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>NKX2-5</td><td>Santa Cruz</td><td>sc-8697 (goat polyclonal)</td><td>NKX2-5-Primary antibody- 1:50 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>GATA4</td><td>Abcam</td><td>ab84593 (rabbit polyclonal)</td><td>GATA4-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>MEF2C</td><td>Santa Cruz</td><td>sc-13268 (goat polyclonal)</td><td>MEF2C-Primary antibody- 1:50 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>Troponin I</td><td>Millipore</td><td>MAB1691 (mouse monoclonal)</td><td>Troponin I-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>Actinin</td><td>Millipore</td><td>MAB1682 (mouse monoclonal)</td><td>Actinin-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>ANP</td><td>Millipore</td><td>AB5490 (mouse polyclonal)</td><td>ANP-Primary antibody- 1:100 dilution, Secondar antibody- 1:200 dilution, in blocking solution</td></tr><tr><td>Alex Fluor-488 checken anti-rabbit</td><td>Life technology</td><td>Ref no. A21441</td><td></td></tr><tr><td>Alex Fluor-594 goat anti-rabbit</td><td>Life technology</td><td>Ref no. A11012</td><td></td></tr><tr><td>Alex Fluor-594 rabbit anti-goat</td><td>Life technology</td><td>Ref no. A11078</td><td></td></tr><tr><td>Alex Fluor-488 checken anti-mouse</td><td>Life technology</td><td>Ref no. A21200</td><td></td></tr><tr><td>Alex Fluor-594 checken anti-goat</td><td>Life technology</td><td>Ref no. A21468</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Culture medium: &lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>CSC maintenance medium</td><td>Millipore</td><td>SCM101</td><td>Note: For CSC culture, PBS or incomplete DMEM medium was used for washing the cells</td></tr><tr><td>cardiomyocytes differentiation medium</td><td>Millipore</td><td>SCM102</td><td></td></tr><tr><td>DMEM</td><td>Sigma-Aldrich</td><td>D5546</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Cell Isolation buffer:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>polysucrose and sodium diatrizoate solution (Histopaque1077)</td><td>Sigma</td><td>10771</td><td></td></tr><tr><td>HBSS</td><td>Gibco</td><td>2018-03</td><td></td></tr><tr><td>Collagenase I</td><td>Sigma</td><td>C0130</td><td></td></tr><tr><td>Dispase solution</td><td>STEMCELL Technologies</td><td>7913</td><td></td></tr><tr><td>PBS</td><td>LONZA</td><td>S1226</td><td></td></tr><tr><td>StemPro Accutase Cell Dissociation Reagent</td><td>Thermoscientific</td><td>A1110501</td><td></td></tr><tr><td>&lt;strong&gt;Other reagents:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>BSA</td><td>Sigma</td><td>A7030</td><td></td></tr><tr><td>Normal checken serum</td><td>Vector laboratory</td><td>S3000</td><td></td></tr><tr><td>DAPI solution</td><td>Applichem</td><td>A100,0010</td><td>Dapi, working concentration-1 &amp;micro;g/mL</td></tr><tr><td>Trypan blue</td><td>Biorad</td><td>145-0013</td><td></td></tr><tr><td>Trypsin</td><td>Sigma</td><td>T4049</td><td></td></tr><tr><td>StemPro Accutase Cell Dissociation Reagent</td><td>Thermo Fisher Scientific</td><td>A1110501</td><td></td></tr><tr><td>Formaldehyde</td><td>Sigma</td><td>158127</td><td></td></tr><tr><td>Triton X-100</td><td>ACROS</td><td>Cas No. 900-293-1</td><td></td></tr><tr><td>Tween 20</td><td>Fisher Sceintific</td><td>Lot No. 160170</td><td></td></tr><tr><td>Ethanol</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Tissue culture materials:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>100 mm petri dish</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>6-well plate</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>24-well plate</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>T-25 flask</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>T-75 flask</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>15 ml conical tube</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>50 mL conical tube</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>40 &amp;micro;m cell stainer</td><td>Fisher Scientific</td><td>22363547</td><td></td></tr><tr><td>100 &amp;micro;m cell stainer</td><td>Fisher Scientific</td><td>22363549</td><td></td></tr><tr><td>0.22 &amp;micro;m filter</td><td>Fisher Scientific</td><td>09-719C</td><td></td></tr><tr><td>10 mL syring</td><td>BD</td><td>Ref no. 309604</td><td></td></tr><tr><td>10 &amp;micro;L, 200 &amp;micro;L, 1000 &amp;micro;L pipette tips</td><td>Fisher Scientific</td><td></td><td></td></tr><tr><td>5 mL, 10mL, 25 mL disposible plastic pipette</td><td>Thermo Scientific</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Instruments&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Centrufuge machine</td><td>Thermo Scientific</td><td>LEGEND X1R centrifuge</td><td></td></tr><tr><td>EVOS microscope</td><td>Life technology</td><td></td><td></td></tr><tr><td>Automated cell counter</td><td>Biorad</td><td></td><td></td></tr><tr><td>Cell counting slide</td><td>Biorad</td><td>145-0011</td><td></td></tr><tr><td>Pippte aid</td><td>Thermo Scientific</td><td>S1 pipet filler</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Surgical Instruments:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Surgical scissors</td><td>Fine Scientific Tool</td><td></td><td></td></tr><tr><td>Fine surgical scissors</td><td>Fine Scientific Tool</td><td></td><td></td></tr><tr><td>Curve shank forceps</td><td>Fine Scientific Tool</td><td></td><td></td></tr><tr><td>Surgical blade</td><td>Fine Scientific Tool</td><td></td><td></td></tr></tbody></table>

isolation, characterization, and differentiation of cardiac stem cells from the adult mouse heart

Myocardial infarction (MI) is a leading cause of morbidity and mortality around the world. A major goal of regenerative medicine is to replenish the dead myocardium after MI. Although several strategies have been used to regenerate myocardium, stem cell therapy remains a major approach to replenish the dead myocardium of an MI heart. Accumulating evidence suggests the presence of resident cardiac stem cells (CSCs) in the adult heart and their endocrine and/or paracrine effects on cardiac regeneration. However, CSC isolation and their characterization and differentiation toward myocardial cells, especially cardiomyocytes, remains a technical challenge. In the present study, we provided a simple method for the isolation, characterization, and differentiation of CSCs from the adult mouse heart. Here, we describe a density gradient method for the isolation of CSCs, where the heart is digested by a 0.2% collagenase II solution. To characterize the isolated CSCs, we evaluated the expression of CSCs/cardiac markers Sca-1, NKX2-5, and GATA4, and pluripotency/stemness markers OCT4, SOX2, and Nanog. We also determined the proliferation potential of isolated CSCs by culturing them in a Petri dish and assessing the expression of the proliferation marker Ki-67. For evaluating the differentiation potential of CSCs, we selected seven- to ten-days cultured CSCs. We transferred them to a new plate with a cardiomyocyte differentiation medium. They are incubated in a cell culture incubator for 12 days, while the differentiation medium is changed every three days. The differentiated CSCs express cardiomyocyte-specific markers: actinin and troponin I. Thus, CSCs isolated with this protocol have stemness and cardiac markers, and they have a potential for proliferation and differentiation toward cardiomyocyte lineage.

In the present study, we isolated CSCs from 10- to 12-week-old C57BL/6J male mice hearts. Here, we have presented a simple method for CSC isolation and characterization using markers of pluripotency. We also presented an elegant method for CSC differentiation and the characterization of CSCs that differentiated toward cardiomyocytes lineage. We observed a spindle shape morphology of 2- to 3-days-cultured CSCs under a phase-contrast microscope (Figure&#160;1A ...

Watch this Scientific Journal Video about Isolation, Characterization, and Differentiation of Cardiac Stem Cells from the Adult Mouse Heart at JoVE.com

Isolation, Characterization, and Differentiation of Cardiac Stem Cells from the Adult Mouse Heart

The overall goal of this article is to standardize the protocol for the isolation, characterization, and differentiation of cardiac stem cells (CSCs) from the adult mouse heart. Here, we describe a density gradient centrifugation method to isolate murine CSCs and elaborated methods for CSC culture, proliferation, and differentiation into cardiomyocytes.

Myocardial infarction (MI) is a leading cause of morbidity and mortality around the world. A major goal of regenerative medicine is to replenish the dead ...

isolation-characterization-differentiation-cardiac-stem-cells-from

Research

JoVE Journal

Biology

6.5K Views.  University of Nebraska Medical Center. The overall goal of this article is to standardize the protocol for the isolation, characterization, and differentiation of cardiac stem cells (CSCs) from the adult mouse heart. Here, we describe a density gradient centrifugation method to isolate murine CSCs and elaborated methods for CSC culture, proliferation, and differentiation into cardiomyocytes.

Video: Isolation, Characterization, and Differentiation of Cardiac Stem Cells from the Adult Mouse Heart

Isolation of Perivascular Multipotent Precursor Cell Populations from Human Cardiac Tissue

Multipotent mesenchymal stem/stromal cells (MSC) were conventionally isolated, through their plastic adherence, from primary tissue digests whilst their anatomical tissue location remained unclear. The recent discovery of defined perivascular and MSC cell marker expression by perivascular cells in multiple tissues by our group and other researchers has provided an opportunity to prospectively isolate and purify specific homogenous subpopulations of multipotent perivascular precursor cells. We have previously demonstrated the use of fluorescent activated cell sorting (FACS) to purify microvascular CD146+CD34- pericytes and vascular CD34+CD146- adventitial cells from human skeletal muscle. Herein we describe a method to simultaneously isolate these two perivascular cell subsets from human myocardium by FACS, based on the expression of a defined set of cell surface markers for positive and negative selections. This method thus makes available two specific subpopulations of multipotent cardiac MSC-like precursor cells for use in basic research and/or therapeutic investigations.

Human cardiac tissue harbours multipotent perivascular precursor cell populations that may be suitable for myocardial regeneration. The technique described here allows for the simultaneous isolation and purification of two multipotent stromal cell populations associated with native blood vessels, i.e. CD146+CD34- pericytes and CD34+CD146- adventitial cells, from the human myocardium.

Multipotent mesenchymal stem/stromal cells (MSC) were conventionally isolated, through their plastic adherence, from primary tissue digests whilst their ...

Developmental Biology

Nuclei Isolation from Mouse Cardiac Progenitor Cells at Single-Cell Resolution

Nuclei Isolation from Mouse Cardiac Progenitor Cells for Epigenome and Gene Expression Profiling at Single-Cell Resolution

The developing heart is a complex structure containing various progenitor cells controlled by complex regulatory mechanisms. The examination of the gene expression and chromatin state of individual cells allows the identification of the cell type and state. Single-cell sequencing approaches have revealed a number of important characteristics of cardiac progenitor cell heterogeneity. However, these methods are generally restricted to fresh tissue, which limits studies with diverse experimental conditions, as the fresh tissue must be processed at once in the same run to reduce the technical variability. Therefore, easy and flexible procedures to produce data from methods such as single-nucleus RNA sequencing (snRNA-seq) and the single-nucleus assay for transposase-accessible chromatin with high-throughput sequencing (snATAC-seq) are needed in this area. Here, we present a protocol to rapidly isolate nuclei for subsequent single-nuclei dual-omics (combined snRNA-seq and snATAC-seq). This method allows the isolation of nuclei from frozen samples of cardiac progenitor cells and can be combined with platforms that use microfluidic chambers.

Author Spotlight: Nuclei Isolation from Mouse Cardiac Progenitor Cells for Epigenome and Gene Expression Profiling at Single-Cell Resolution  

Here, we present a protocol describing cell nuclei preparation. After microdissection and enzymatic dissociation of cardiac tissue into single cells, the progenitor cells were frozen, followed by isolation of pure viable cells, which were used for single-nucleus RNA sequencing and the single-nucleus assay for transposase-accessible chromatin with high-throughput sequencing analyses.

The developing heart is a complex structure containing various progenitor cells controlled by complex regulatory mechanisms. The examination of the gene ...

Isolating Primary Melanocyte-like Cells from the Mouse Heart

We identified a novel population of melanocyte-like cells (also known as cardiac melanocytes) in the hearts of mice and humans that contribute to atrial arrhythmia triggers in mice. To investigate the electrical and biological properties of cardiac melanocytes we developed a procedure to isolate them from mouse hearts that we derived from those designed to isolate neonatal murine cardiomyocytes. In order to obtain healthier cardiac melanocytes suitable for more extensive patch clamp or biochemical studies, we developed a refined procedure for isolating and plating cardiac melanocytes based on those originally designed to isolate cutaneous melanocytes. The refined procedure is demonstrated in this review and produces larger numbers of healthy melanocyte-like cells that can be plated as a pure population or with cardiomyocytes.

In this protocol, we identified a novel population of melanocyte-like cells (also known as cardiac melanocytes) in the hearts of mice and humans that contribute to atrial arrhythmia triggers in mice.&#160;

We identified a novel population of melanocyte-like cells (also known as cardiac melanocytes) in the hearts of mice and humans that contribute to atrial ...

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes

The use of primary cardiomyocytes (CMs) in culture has provided a powerful complement to murine models of heart disease in advancing our understanding of heart disease. In particular, the ability to study ion homeostasis, ion channel function, cellular excitability and excitation-contraction coupling and their alterations in diseased conditions and by disease-causing mutations have led to significant insights into cardiac diseases. Furthermore, the lack of an adequate immortalized cell line to mimic adult CMs, and the limitations of neonatal CMs (which lack many of the structural and functional biomechanics characteristic of adult CMs) in culture have hampered our understanding of the complex interplay between signaling pathways, ion channels and contractile properties in the adult heart strengthening the importance of studying adult isolated cardiomyocytes. Here, we present methods for the isolation, culture, manipulation of gene expression by adenoviral-expressed proteins, and subsequent functional analysis of cardiomyocytes from the adult mouse. The use of these techniques will help to develop mechanistic insight into signaling pathways that regulate cellular excitability, Ca2+ dynamics and contractility and provide a much more physiologically relevant characterization of cardiovascular disease.

Here we describe the isolation of adult mouse cardiomyoctyes using a Langendorff perfusion system. The resulting cells are Ca2+-tolerant, electrically quiescent and can be cultured and transfected with adeno- or lentiviruses to manipulate gene expression. Their functionality can also be analyzed using the MMSYS system and patch clamp techniques.

The use of primary cardiomyocytes (CMs) in culture has provided a powerful complement to murine models of heart disease in advancing our understanding of ...

Isolation and Physiological Analysis of Mouse Cardiomyocytes

Cardiomyocytes, the workhorse cell of the heart, contain exquisitely organized cytoskeletal and contractile elements that generate the contractile force used to pump blood. Individual cardiomyocytes were first isolated over 40 years ago in order to better study the physiology and structure of heart muscle. Techniques have rapidly improved to include enzymatic digestion via coronary perfusion. More recently, analyzing the contractility and calcium flux of isolated myocytes has provided a vital tool in the cellular and sub-cellular analysis of heart failure. Echocardiography and EKGs provide information about the heart at an organ level only. Cardiomyocyte cell culture systems exist, but cells lack physiologically essential structures such as organized sarcomeres and t-tubules required for myocyte function within the heart. In the protocol presented here, cardiomyocytes are isolated via Langendorff perfusion. The heart is removed from the mouse, mounted via the aorta to a cannula, perfused with digestion enzymes, and cells are introduced to increasing calcium concentrations. Edge and sarcomere detection software is used to analyze contractility, and a calcium binding fluorescent dye is used to visualize calcium transients of electrically paced cardiomyocytes; increasing understanding of the role cellular changes play in heart dysfunction. Traditionally used to test drug effects on cardiomyocytes, we employ this system to compare myocytes from WT mice and mice with a mutation that causes dilated cardiomyopathy. This protocol is unique in its comparison of live cells from mice with known heart function and known genetics. Many experimental conditions are reliably compared, including genetic or environmental manipulation, infection, drug treatment, and more. Beyond physiologic data, isolated cardiomyocytes are easily fixed and stained for cytoskeletal elements. Isolating cardiomyocytes via perfusion is an extremely versatile method, useful in studying cellular changes that accompany or lead to heart failure in a variety of experimental conditions.

Individual cardiomyocytes from wild type and mutant mice can be isolated from the heart in order to study their contractility and calcium transients. This allows characterization of the contribution of cellular dysfunction to heart dysfunction from any cause.

Cardiomyocytes, the workhorse cell of the heart, contain exquisitely organized cytoskeletal and contractile elements that generate the contractile force ...

Isolation and Culture of Adult Mouse Cardiomyocytes for Cell Signaling and in vitro Cardiac Hypertrophy

Technological advances have made genetically modified mice, including transgenic and gene knockout mice, an essential tool in many research fields. Adult cardiomyocytes are widely accepted as a good model for cardiac cellular physiology and pathophysiology, as well as for pharmaceutical intervention. Genetically modified mice preclude the need for complicated cardiomyocyte infection processes to generate the desired genotype, which are inefficient due to cardiomyocytes&#8217; terminal differentiation. Isolation and culture of high quantity and quality functional cardiomyocytes will dramatically benefit cardiovascular research and provide an important tool for cell signaling transduction research and drug development. Here, we describe a well-established method for isolation of adult mouse cardiomyocytes that can be implemented with little training. The mouse heart is excised and cannulated to an isolated heart system, then perfused with a calcium-free and high potassium buffer followed by type II collagenase digestion in Langendorff retrograde perfusion mode. This protocol yields a consistent result for the collection of functional adult mouse cardiomyocytes from a variety of genetically modified mice.

Isolation and Culture of Adult Mouse Cardiomyocytes for Cell Signaling and in vitro Cardiac Hypertrophy

We describe a reliable method for isolation of adult mouse cardiomyocytes. This protocol yields a consistent result for the culture of functional adult cardiomyocytes from a variety of genetically modified mice.

Technological advances have made genetically modified mice, including transgenic and gene knockout mice, an essential tool in many research fields. Adult ...

Isolation, Culture and Transduction of Adult Mouse Cardiomyocytes

Cultured cardiomyocytes can be used to study cardiomyocyte biology using techniques that are complementary to in vivo systems. For example, the purity and accessibility of in vitro culture enables fine control over biochemical analyses, live imaging, and electrophysiology. Long-term culture of cardiomyocytes offers access to additional experimental approaches that cannot be completed in short term cultures. For example, the in vitro investigation of dedifferentiation, cell cycle re-entry, and cell division has thus far largely been restricted to rat cardiomyocytes, which appear to be more robust in long-term culture. However, the availability of a rich toolset of transgenic mouse lines and well-developed disease models make mouse systems attractive for cardiac research. Although several reports exist of adult mouse cardiomyocyte isolation, few studies demonstrate their long-term culture. Presented here, is a step-by-step method for the isolation and long-term culture of adult mouse cardiomyocytes. First, retrograde Langendorff perfusion is used to efficiently digest the heart with proteases, followed by gravity sedimentation purification. After a period of dedifferentiation following isolation, the cells gradually attach to the culture and can be cultured for weeks. Adenovirus cell lysate is used to efficiently transduce the isolated cardiomyocytes. These methods provide a simple, yet powerful model system to study cardiac biology.

This protocol describes a step-by-step method for the reproducible isolation and long-term culture of adult mouse cardiomyocytes with high yield, purity, and viability.

Cultured cardiomyocytes can be used to study cardiomyocyte biology using techniques that are complementary to in vivo systems. For example, the purity and ...

Methods for the Isolation, Culture, and Functional Characterization of Sinoatrial Node Myocytes from Adult Mice

Sinoatrial node myocytes (SAMs) act as the natural pacemakers of the heart, initiating each heart beat by generating spontaneous action potentials (APs). These pacemaker APs reflect the coordinated activity of numerous membrane currents and intracellular calcium cycling. However the precise mechanisms that drive spontaneous pacemaker activity in SAMs remain elusive. Acutely isolated SAMs are an essential preparation for experiments to dissect the molecular basis of cardiac pacemaking. However, the indistinct anatomy, complex microdissection, and finicky enzymatic digestion conditions have prevented widespread use of acutely isolated SAMs. In addition, methods were not available until recently to permit longer-term culture of SAMs for protein expression studies. Here we provide a step-by-step protocol and video demonstration for the isolation of SAMs from adult mice. A method is also demonstrated for maintaining adult mouse SAMs in vitro and for expression of exogenous proteins via adenoviral infection. Acutely isolated and cultured SAMs prepared via these methods are suitable for a variety of electrophysiological and imaging studies.

Methods are demonstrated for the isolation of sinoatrial node myocytes (SAMs) from adult mice for patch clamp electrophysiology or imaging studies. Isolated cells can be used directly or can be maintained in culture to permit expression of proteins of interest, such as genetically encoded reporters.

Sinoatrial node myocytes (SAMs) act as the natural pacemakers of the heart, initiating each heart beat by generating spontaneous action potentials (APs). ...

A Simple and Effective Method to Consistently Isolate Mouse Cardiomyocytes

The need for reproducible yet technically simple methods yielding high-quality cardiomyocytes is essential for research in cardiac biology. Cellular and molecular functional experiments (e.g., contraction, electrophysiology, calcium cycling, etc.) on cardiomyocytes are the gold standard for establishing mechanism(s) of disease. The mouse is the species of choice for functional experiments and the described technique is specifically for the isolation of mouse cardiomyocytes. Previous methods requiring a Langendorff apparatus require high levels of training and precision for aortic cannulation, often resulting in ischemia. The field is shifting toward Langendorff-free isolation methods that are simple, are reproducible, and yield viable myocytes for physiological data acquisition and culture. These methods greatly diminish ischemia time compared to aortic cannulation and result in reliably obtained cardiomyocytes. Our adaptation to the Langendorff-free method includes an initial perfusion with ice-cold clearing solution, use of a stabilizing platform that ensures a steady needle during perfusion, and additional digestion steps to ensure reliably obtained cardiomyocytes for use in functional measurements and culture. This method is simple and quick to perform and requires little technical skill.

The gold standard in cardiology for cellular and molecular functional experiments are cardiomyocytes. This article describes adaptations to the non-Langendorff technique to isolate mouse cardiomyocytes.

The need for reproducible yet technically simple methods yielding high-quality cardiomyocytes is essential for research in cardiac biology. Cellular and ...

Medicine

Isolation and Characterization of Adult Cardiac Fibroblasts and Myofibroblasts

Cardiac fibrosis in response to injury is a physiological response to wound healing. Efforts have been made to study and target fibroblast subtypes that mitigate fibrosis. However, fibroblast research has been hindered due to the lack of universally acceptable fibroblast markers to identify quiescent as well as activated fibroblasts. Fibroblasts are a heterogenous cell population, making them difficult to isolate and characterize. The presented protocol describes three different methods to enrich fibroblasts and myofibroblasts from uninjured and injured mouse hearts. Using a standard and reliable protocol to isolate fibroblasts will enable the study of their roles in homeostasis as well as fibrosis modulation.

Obtaining a pure population of fibroblasts is crucial to studying their role in wound repair and fibrosis. Described here is a detailed method to isolate fibroblasts and myofibroblasts from uninjured and injured mouse hearts followed by characterization of their purity and functionality by immunofluorescence, RTPCR, fluorescence-assisted cell sorting, and collagen gel contraction.

Cardiac fibrosis in response to injury is a physiological response to wound healing. Efforts have been made to study and target fibroblast subtypes that ...

Isolation, Characterization, and Differentiation of Cardiac Stem Cells from the Adult Mouse Heart

Summary

Explore More Videos

Chapters in this video

Isolation of Perivascular Multipotent Precursor Cell Populations from Human Cardiac Tissue

Nuclei Isolation from Mouse Cardiac Progenitor Cells for Epigenome and Gene Expression Profiling at Single-Cell Resolution

Isolating Primary Melanocyte-like Cells from the Mouse Heart

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes

Isolation and Physiological Analysis of Mouse Cardiomyocytes

Isolation and Culture of Adult Mouse Cardiomyocytes for Cell Signaling and in vitro Cardiac Hypertrophy

Isolation, Culture and Transduction of Adult Mouse Cardiomyocytes

Methods for the Isolation, Culture, and Functional Characterization of Sinoatrial Node Myocytes from Adult Mice

A Simple and Effective Method to Consistently Isolate Mouse Cardiomyocytes

Isolation and Characterization of Adult Cardiac Fibroblasts and Myofibroblasts