ACD is supported by a grant from the National Institute of Health (R01-CA177875). LX is a fellow in the HHMI-funded translational medicine program at UNC Chapel Hill. JVM is supported by a T32 pre-doctoral fellowship from the Integrative Vascular Biology Program at UNC Chapel Hill. We thank Clayton Davis for assistance with confocal microscopy.

The following protocol is carried out according to guidelines established by the Department of Laboratory Animal Medicine at the University of North Carolina at Chapel Hill.
1. Prepare the Following Material and Reagents Before Starting
<ol>
	<li>Prepare EC media by supplementing 400 ml&#160;low glucose (1 g/L D-glucose or LG) Dulbecco&#39;s Modified Eagle&#39;s medium (DMEM) with 50 ml heat-inactivated fetal bovine serum, 50 ml Nu-Serum IV, 5 ml antibiotic-antimycotic, and the hFGF, VEGF, hEGF, R3-IGF-1, and heparin components from the commercial kit.</li>
	<li>Prepare 500 ml FACS buffer (0.5% BSA and 2 mM EDTA in PBS); filter through a sterile 0.22 &#181;m filter cup.</li>
	<li>Sterilize or disinfect dissecting board.</li>
	<li>Sterilize dissection pins, surgical scissors, and dissectors.</li>
</ol>
2. EC Isolation (Day 1, ~5 hr)
<ol>
	<li>Euthanize mouse with carbon dioxide or other methods compliant with the Institutional Animal Care and Use Committee (IACUC) policies. 
	Note: Multiple mammary tumors varying in size (5 - 15 mm in diameter) may develop in a single genetically modified mouse such as C3-TAg, be sure to harvest all of them for TEC isolation. If using tumors that are orthotopically engrafted in mice, pool two to three 1 cm3 tumors for a single EC isolation. Here we use mammary tumors as a demonstration, but the protocol can be modified for other types of tumors.</li>
	<li>Disinfect mouse by spraying or wiping the mouse ventral side with ample amount of 75% v/v ethanol.</li>
	<li>Resect tumors with one pair of scissors and dissectors using aseptic techniques in a sterile hood or at a clean bench.
	<ol>
		<li>Stretch out and pin the limbs of the mice on a dissecting board. Make a midline ventral incision with the scissors without opening the peritoneum. Dissect laterally between the skin and the peritoneum towards the mammary glands where tumors are located. Do not open the peritoneum.</li>
		<li>Excise only tumor tissue from the mammary glands, leaving out normal mammary margins. Carefully trim off non-tumor tissues such as skin and muscles, and place dissected tumors in a conical tube containing 30 ml of LG-DMEM on ice.</li>
	</ol>
	</li>
	<li>Bring tumor samples to tissue culture hood; wash tissues with sterile LG-DMEM 1 - 2 times.</li>
	<li>Transfer tumors from the conical tube to a sterile tissue-culture petri dish, add 2 ml of LG-DMEM in the dish, and mince with a pair of sterile scissors into pieces &#60;5 mm.</li>
	<li>Add 5 ml of collagenase (stock = 2 mg/ml in Hank&#8217;s Balanced Salt Solution, hereafter HBSS), 1 ml of dispase (stock = 2.5 U/ml in HBSS) and 75 &#956;l of deoxyribonuclease (stock = 1 mg/ml in PBS) into the petri dish. Total volume is now ~10 ml.</li>
	<li>Transfer the collagenase/tissue mix from the petri dish to a tissue-dissociator tube and run on a tissue dissociator for 60 sec twice (pre-set dissociation program on the dissociator: 1,270 total rounds per run). Incubate with light shaking on a shaker for 75 min at 37 &#176;C.</li>
	<li>Filter digested tissue through a 100 &#956;m cell strainer over a 50 ml conical tube. Rinse filter with 5 ml of FACS buffer to wash any remaining cells. Spin at 280 x g for 5 min and carefully aspirate the supernatant without disturbing the cell pellet.</li>
	<li>Dilute 1 ml of stock RBC lysis buffer (10x) in 9 ml of sterile water. Lyse red blood cells with 10 ml of lysis buffer (1x), and immediately spin 5 min at 280 x g. Note: This step can be skipped if little blood is visible.</li>
	<li>Resuspend in 10 ml of FACS buffer. Mix 10 &#956;l of cell suspension with 10 &#956;l of trypan blue, and count live cells using a hemocytometer .</li>
	<li>Resuspend cells at ~107 cells/100 &#956;l. Add 10 &#956;l of FcR block per 100 &#956;l of cell suspension, and incubate on ice for 10 min.</li>
	<li>Add rat-anti mouse PE-conjugated CD31 antibody according to Table 1. Incubate on ice for 10 - 15 min and flick tube occasionally.</li>
	<li>Add 10 ml of FACS buffer to the tube and spin at 280 x g for 5 min. Carefully remove the supernatant, and wash the cell pellet again with 5 ml of FACS buffer. Centrifuge to pellet cells. Aspirate supernatant without disturbing cell pellet.</li>
	<li>Add FACS buffer and anti-PE microbeads according to Table 2. Incubate on ice for 10 - 15 min. Flick tube occasionally.</li>
	<li>Add 10 ml of FACS buffer and spin samples at 280 x g for 5 min; wash once with 5 ml of FACS buffer and centrifuge again. Aspirate supernatant without disturbing pellet.</li>
	<li>Bring volume to 300 &#956;l in FACS buffer. Spin through 35 &#956;m cell-strainer capped tube 5 min at 280 x g. Use 2 tubes and a larger volume if needed.</li>
	<li>Set up magnetic multistand and magnetic columns in hood, attach a column to the separator and equilibrate the column with 2 ml of FACS buffer.</li>
	<li>Aspirate the supernatant and resuspend the cell pellet in 0.5 - 1 ml of FACS buffer.</li>
	<li>Pass the cell suspension through the equilibrated magnetic column.</li>
	<li>Wash the column three times with 2 ml of FACS buffer, and collect flow-through (FT) in a 15 ml tube (FT fraction).</li>
	<li>Take the column off the separator and elute with 2 ml of FACS buffer into another 15 ml tube (eluate fraction). Use plunger to ensure all cells are off the column. Repeat the elution two more times with 2 ml of FACS buffer each time.</li>
	<li>Spin the eluate at 280 x g for 5 min.</li>
	<li>Remove the supernatant and resuspend the pellet in 10 ml of EC media.</li>
	<li>Equally divide the eluate fraction (~ 6 ml) into 10 cm gelatin-coated dishes. For three 1 cm3 tumors, plate eluted cells in at least four plates. Alternatively, plate eluted cells at different concentrations in multiple plates (e.g., seed 0.5 ml, 1 ml, 1.5 ml, and 3 ml of the eluate into four plates) to ensure that at least one plate is sparsely seeded with eluted cells. Check that the confluency of the attached cells is at ~1% the next day (i.e., approximately 1.0 - 2.0 X 105 attached cells). 
	Note: The cells need to be plated sparse so that EC colonies can form without being contaminated by other cell types.</li>
	<li>Plate FT fraction in one 10 cm dish to let cells recover O/N. Check that the plate is 80&#160;- 100% confluent the next day. Freeze down the cells (-80 &#176;C) in 250 &#181;l cell-freezing media in a cryotube and store them in liquid nitrogen the next day.&#160;Note: FT fraction can be used for tumor cell isolation at a later stage and/or as a negative control for EC gene expression analysis of the isolated EC clones.</li>
	<li>Change media every 2 - 3 days. Colonies start to form after 7 - 10 days. Small EC colonies can be identified as early as day 3. Mark the colonies with a fine-tip marker on the bottom of the dish.</li>
	<li>Scrape off non-specific cells surrounding the identified colonies with a sterile 200 &#181;l pippet tip.</li>
</ol>
3. Colony Selection Using Cloning Rings
<ol>
	<li>Change media every 2 - 3 days. EC purity can be checked by LDL (DiI-Ac-LDL) addition at about 5 - 7 days. Add 50 &#181;l of LDL per 10 ml EC medium and incubate for 3 - 4 hr before checking the cells under fluorescence microscope. 
	Note: Multiple LDL+ EC clones could be observed at ~day 7.</li>
	<li>Start harvesting EC colonies when they reach diameters of 3 - 5 mm in size. (Choose big colonies that are packed with small LDL+ cells for best results.)</li>
	<li>Before harvesting EC with cloning rings, pre-coat a few 6-well plates with 0.5% gelatin. Aspirate gelatin, add 2 ml of EC media to each well, and keep the plates in an incubator until needed.</li>
	<li>Scrape off non-EC on the edges of the colonies to make sure no other cell types will be trapped within the cloning ring.</li>
	<li>Using a phase-contrast microscope (4X or 10X objective), outline with a fine-tip marker on the bottom of the culture dish the areas containing EC colonies.</li>
	<li>Wash the plate with 10 ml of PBS and leave a very thin layer of PBS in the plate when aspirating. (Important: a small amount (~0.5 ml) of PBS will keep cells alive during the cloning-ring procedure; also, tissue adhesive needs water to bond.)</li>
	<li>Choose a cloning ring of appropriate size. Use a pair of dissecting forceps to pick up a ring, and with a 10 &#181;l&#160;pipet tip evenly apply a small amount of tissue adhesive onto the cloning ring. 
	Note: use only minimal amount (~0.2 &#956;l for a small ring) of tissue adhesive on cloning rings, and make sure tissue adhesive is spread out evenly around the bottom surface to ensure good sealing. Excessive tissue adhesive produces heat and forms films that may kill cells.</li>
	<li>Place the cloning ring over the EC colony. Gently press down the cloning ring to glue the ring onto the plate. Ensure that the colonies are not dried out before gluing the ring.</li>
	<li>Immediately pipet 25 &#181;l&#160;of enzymatic cell detachment solution into the cloning ring and incubate ~1 min or until the cells are loosely attached.</li>
	<li>Pipet cells in the cloning ring drop-wise into one well of a 6-well plate containing pre-warmed EC media. (Important: Do not shake the plate to disperse cells; EC prefer to grow in tight clusters.) Wash the cloning ring with 50 - 100 &#181;l&#160;EC media to collect as many cells as possible, and transfer all washes into the same 6-well.</li>
	<li>If some colonies in the 10 cm dish are too small to harvest, add 10 ml fresh media, let the colonies grow for a few more days, and repeat the cloning ring procedure again.</li>
	<li>Grow harvested colonies in 6-well plates until 80 - 100% confluent, and transfer cells to 3 wells of a 6-well plate, before expanding them in a 10 cm tissue culture dish. Scrape off contaminant cells. Repeat another round of cloning ring procedure (Steps 3.5 - 3.10) if necessary. Keep cells relatively confluent (~60 - 70%) when expanding. EC may stop growing if plated too sparse.</li>
	<li>Characterize EC by FACS, staining, PCR, etc. Note that Dil-Ac-LDL is fluorescent and may interfere with PE or other fluorescent antibodies for FACS.</li>
</ol>

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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=Vessel+wall-derived+endothelial+cells+rapidly+proliferate+because+they+contain+a+complete+hierarchy+of+endothelial+progenitor+cells.">Vessel wall-derived endothelial cells rapidly proliferate because they contain a complete hierarchy of endothelial progenitor cells.</a> Blood. 105 (7), 2783-2786 (2005).</li></ol>

The authors have nothing to disclose.

Due to the difficulties in obtaining pure primary TEC cultures, many in vitro studies substitute TEC with commercially available EC lines or primary EC such as human umbilical vein EC (HUVEC) 13. However, these EC populations from normal tissues may only serve as a proxy for TEC which differ markedly from their normal counterparts. For example, TEC are phenotypically and functionally abnormal in vivo and some of these abnormalities may be transmittable in vitro 14-18. TEC ...

Endothelial cells (EC) are essential during the development of solid tumors. From initiation of the angiogenic switch in dormant tumors to dissemination and seeding of metastases at distant sites, EC form the conduits that provide blood, oxygen, and nutrients to sustain tumor growth 1. As recently suggested, EC also have perfusion-independent functions and form a niche that supports the growth of cancer stem cells and other tumor stromal cells 2-5. Thus, highly purified tumor-specific EC (TEC) for in vitro culture allows for routine functional studies that will shed light on novel molecular mechanisms mediating tumor angiogenesis and cross talk with tumor cells.
EC are highly specialized depending on the tissue of origin 6. Due to the heterogeneous nature of different tumor types and the tumor microenvironment, TEC may also display unique features that reflect a tumor-specific specialization of the vasculature. For example, there is striking variability in the gene expression signatures in TEC isolated from different types or grades of tumors 7,8. However, frequent co-purification of non-EC, especially tumor-associated fibroblasts and tumor cells, with TEC can confound genome-wide expression analyses. These unwanted cell types are especially problematic in studies that rely on long-term in vitro expansion of TEC cultures.
Described here is a high-fidelity method that consistently produces pure EC cultures from tumors and other tissues. Following immunomagnetic column enrichment of EC fractions and removal of co-purified non-EC, an additional cloning-ring step to capture pure EC colonies is used 9. Each colony can be expanded in culture for multiple passages without the emergence of contaminating non-EC. This method also yields multiple EC clones from a single isolation procedure, which is ideal for the study of endothelial heterogeneity. In addition, it is shown that Cdh5cre:ZsGreenl/s/l reporter mice are a valuable tool for generating &#8220;fate-mapped&#8221; and indelibly-marked EC which maintain ZsGreen fluorescence in culture 10. With minor adjustments to the protocol, this method should be adaptable to different tumor types or normal tissues.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Antibiotic-Antimycotic&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>A5955</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Modified Eagle&#39;s medium (1 g/L D-glucose) (LG-DMEM)</td>
			<td>Gibco</td>
			<td>11885-084</td>
			<td></td>
		</tr>
		<tr>
			<td>EGM-2 Bullet Kit&#160;</td>
			<td>Lonza</td>
			<td>CC4176</td>
			<td>Not all components used</td>
		</tr>
		<tr>
			<td>Fetal bovine serum (Hyclone)</td>
			<td>Thermo Scientific</td>
			<td>SH30071.03</td>
			<td>Heat inactivated at 56&#176;C for 30 min</td>
		</tr>
		<tr>
			<td>Nu-Serum IV</td>
			<td>Corning</td>
			<td>CB-51004</td>
			<td></td>
		</tr>
		<tr>
			<td>Hank&#39;s Balanced Salt Solution (HBBS)</td>
			<td>Gibco</td>
			<td>14175-095</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-buffered saline (PBS)</td>
			<td>Gibco</td>
			<td>14190-144</td>
			<td></td>
		</tr>
		<tr>
			<td>FACS buffer&#160;</td>
			<td>-</td>
			<td>-</td>
			<td>0.5 % BSA and 2 mM EDTA in PBS, filtered through a 0.22 &#956;m filter</td>
		</tr>
		<tr>
			<td>75% v/v ethanol for disinfection</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-PE microbeads&#160;</td>
			<td>Miltenyi Biotech</td>
			<td>130-048-801</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin (BSA) fraction V, 7.5%</td>
			<td>Gibco</td>
			<td>15260-37</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell freezing media (Bambanker)</td>
			<td>Wako Chemicals</td>
			<td>302-14681</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase type II&#160;&#160;</td>
			<td>Worthington Biochemical</td>
			<td>LS004176</td>
			<td>Make stock concentration 2 mg/ml in HBSS</td>
		</tr>
		<tr>
			<td>Deoxyribonuclease I (DNase)</td>
			<td>Worthington Biochemical</td>
			<td>LS002004</td>
			<td>Make stock concentration 1 mg/mL in PBS</td>
		</tr>
		<tr>
			<td>Dil-Ac-LDL</td>
			<td>Biomedical Technologies</td>
			<td>BT-902</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA, 0.5M, pH 8.0</td>
			<td>Cellgro</td>
			<td>46-034-CL</td>
			<td></td>
		</tr>
		<tr>
			<td>Enzymatic cell detachment solution (Accutase)</td>
			<td>Sigma-Aldrich</td>
			<td>A6964-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Gelatin, 2 % in water, tissue culture grade</td>
			<td>Sigma-Aldrich</td>
			<td>G1393-100ML</td>
			<td>Dilute in PBS to make 0.5 % gelatin solution</td>
		</tr>
		<tr>
			<td>Mouse FcR Blocking Reagent&#160;</td>
			<td>Miltenyi Biotech</td>
			<td>130-092-575</td>
			<td></td>
		</tr>
		<tr>
			<td>Neutral protease (Dispase)</td>
			<td>Worthington Biochemical</td>
			<td>LS02104</td>
			<td>Make stock concentration 2.5 U/mL in HBSS</td>
		</tr>
		<tr>
			<td>PE-rat anti-mouse CD31 antibody</td>
			<td>BD Pharmingen</td>
			<td>553373</td>
			<td></td>
		</tr>
		<tr>
			<td>RBC lysis buffer (BD Pharm Lyse)</td>
			<td>BD Pharmingen</td>
			<td>555899</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile water</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue, 0.4 %&#160;</td>
			<td>Life Technologies</td>
			<td>15250-061</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mm tissue culture dishes</td>
			<td>Corning</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL conical tubes (sterile)</td>
			<td>Corning</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL conical tubes (sterile)&#160;</td>
			<td>Corning</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>6-well tissue culture plates</td>
			<td>Corning</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue-dissociator tubes (gentleMACS) C tubes)&#160;</td>
			<td>Miltenyi Biotech</td>
			<td>130-093-237</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell Separator&#160; (MidiMACS)</td>
			<td>Miltenyi Biotech</td>
			<td>130-042-302</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell strainer 100 &#956;m&#160;</td>
			<td>Corning</td>
			<td>352360</td>
			<td></td>
		</tr>
		<tr>
			<td>Cloning rings (assorted sizes)</td>
			<td>Bel-Art Products</td>
			<td>378470000</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryotubes</td>
			<td>Thermo Scientific</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting board</td>
			<td>-</td>
			<td>-</td>
			<td>Sterilize or disinfect with 75% v/v ethanol before use&#160;</td>
		</tr>
		<tr>
			<td>Dissecting forceps and scissors</td>
			<td>-</td>
			<td>-</td>
			<td>Sterilize before use&#160;</td>
		</tr>
		<tr>
			<td>Dissecting pins 2&#34;</td>
			<td>-</td>
			<td>-</td>
			<td>Sterilize before use&#160;</td>
		</tr>
		<tr>
			<td>FACS tubes with 35 &#956;m filter cap</td>
			<td>Corning</td>
			<td>352235</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter cup (Stericup, 0.22 &#956;m)</td>
			<td>Millipore</td>
			<td>SCGPU05RE</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine-tip marker</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>LS Columns</td>
			<td>Miltenyi Biotech</td>
			<td>130-042-401</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic Multistand</td>
			<td>Miltenyi Biotech</td>
			<td>130-042-303</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue adhesive (Vetbond)</td>
			<td>3M</td>
			<td>1469SB</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5810R</td>
			<td>Or a centrifuge with similar capacity for 15 mL and 50 mL conical tube centrifugation</td>
		</tr>
		<tr>
			<td>Tissue culture hood</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue dissociator (gentleMACS)</td>
			<td>Miltenyi Biotech</td>
			<td>130-093-235</td>
			<td>Preset program &#34;m_impTumor_01&#34; used for tissue dissociation&#160;</td>
		</tr>
		<tr>
			<td>Liquid nitrogen freezer</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Microplate or rotary shaker</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Phase contrast light microscope</td>
			<td>-</td>
			<td>-</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation and culture expansion of tumor-specific endothelial cells

Freshly isolated tumor-specific endothelial cells (TEC) can be used to explore molecular mechanisms of tumor angiogenesis and serve as an in vitro model for developing new angiogenesis inhibitors for cancer. However, long-term in vitro expansion of murine endothelial cells (EC) is challenging due to phenotypic drift in culture (endothelial-to-mesenchymal transition) and contamination with non-EC. This is especially true for TEC which are readily outcompeted by co-purified fibroblasts or tumor cells in culture. Here, a high fidelity isolation method that takes advantage of immunomagnetic enrichment coupled with colony selection and in vitro expansion is described. This approach generates pure EC fractions that are entirely free of contaminating stromal or tumor cells. It is also shown that lineage-traced Cdh5cre:ZsGreenl/s/l reporter mice, used with the protocol described herein, are a valuable tool to verify cell purity as the isolated EC colonies from these mice show durable and brilliant ZsGreen fluorescence in culture.

EC represent only minor a fraction of the total cell population in most adult tissues 11. It is therefore important to fully digest the harvested tissue into a single-cell suspension that ensures the maximal release of EC from extracellular matrix (ECM) and connective tissues. In our experience, CD31-mediated immunomagnetic selection only provides enriched but not pure EC fractions; therefore, another crucial step is the physical removal of co-purified non-EC and selection/expansion of EC colonies using clonin...

Watch this Scientific Journal Video about Isolation and Culture Expansion of Tumor-specific Endothelial Cells at JoVE.com

Isolation and Culture Expansion of Tumor-specific Endothelial Cells

We report a reliable method to isolate and culture primary tumor-specific endothelial cells from genetically engineered mouse models.

Freshly isolated tumor-specific endothelial cells (TEC) can be used to explore molecular mechanisms of tumor angiogenesis and serve as an in vitro model ...

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Medicine

11.1K Views.  University of North Carolina at Chapel Hill. We report a reliable method to isolate and culture primary tumor-specific endothelial cells from genetically engineered mouse models. 

Video: Isolation and Culture Expansion of Tumor-specific Endothelial Cells

Isolation, Characterization and Comparative Differentiation of Human Dental Pulp Stem Cells Derived from Permanent Teeth by Using Two Different Methods

Developing wisdom teeth are easy-accessible source of stem cells during the adulthood which could be obtained by routine orthodontic treatments. Human pulp-derived stem cells (hDPSCs) possess high proliferation potential with multi-lineage differentiation capacity compare to the ordinary source of adult stem cells1-8; therefore, hDPSCs could be the good candidates for autologous transplantation in tissue engineering and regenerative medicine. Along with these benefits, possessing the mesenchymal stem cells (MSC) features, such as immunolodulatory effect, make hDPSCs more valuable, even in the case of allograft transplantation6,9,10. Therefore, the primary step for using this source of stem cells is to select the best protocol for isolating hDPSCs from pulp tissue. In order to achieve this goal, it is crucial to investigate the effect of various isolation conditions on different cellular behaviors, such as their common surface markers &amp; also their differentiation capacity.
Thus, here we separate human pulp tissue from impacted third molar teeth, and then used both existing protocols based on literature, for isolating hDPSCs,11-13 i.e. enzymatic dissociation of pulp tissue (DPSC-ED) or outgrowth from tissue explants (DPSC-OG). In this regards, we tried to facilitate the isolation methods by using dental diamond disk. Then, these cells characterized in terms of stromal-associated Markers (CD73, CD90, CD105 &amp; CD44), hematopoietic/endothelial Markers (CD34, CD45 &amp; CD11b), perivascular marker, like CD146 and also STRO-1. Afterwards, these two protocols were compared based on the differentiation potency into odontoblasts by both quantitative polymerase chain reaction (QPCR) &amp; Alizarin Red Staining. QPCR were used for the assessment of the expression of the mineralization-related genes (alkaline phosphatase; ALP, matrix extracellular phosphoglycoprotein; MEPE &amp; dentin sialophosphoprotein; DSPP).14

The method described isolation and characterization of human Dental Pulp Stem Cells (hDPSCs) by using either enzymatic dissociation of pulp (DPSC-ED) or direct outgrowth of stem cells from pulp tissue explants (DPSC-OG). Then followed by in vitro comparative differentiation of both types of hDPSCs into odontoblasts.

Developing wisdom teeth are easy-accessible source of stem cells during the adulthood which could be obtained by routine orthodontic treatments. Human ...

Patient Derived Cell Culture and Isolation of CD133+ Putative Cancer Stem Cells from Melanoma

Despite improved treatments options for melanoma available today, patients with advanced malignant melanoma still have a poor prognosis for progression-free and overall survival. Therefore, translational research needs to provide further molecular evidence to improve targeted therapies for malignant melanomas. In the past, oncogenic mechanisms related to melanoma were extensively studied in established cell lines. On the way to more personalized treatment regimens based on individual genetic profiles, we propose to use patient-derived cell lines instead of generic cell lines. Together with high quality clinical data, especially on patient follow-up, these cells will be instrumental to better understand the molecular mechanisms behind melanoma progression.
Here, we report the establishment of primary melanoma cultures from dissected fresh tumor tissue. This procedure includes mincing and dissociation of the tissue into single cells, removal of contaminations with erythrocytes and fibroblasts as well as primary culture and reliable verification of the cells' melanoma origin.
Recent reports revealed that melanomas, like the majority of tumors, harbor a small subpopulation of cancer stem cells (CSCs), which seem to exclusively fuel tumor initiation and progression towards the metastatic state. One of the key markers for CSC identification and isolation in melanoma is CD133. To isolate CD133+ CSCs from primary melanoma cultures, we have modified and optimized the Magnetic-Activated Cell Sorting (MACS) procedure from Miltenyi resulting in high sorting purity and viability of CD133+ CSCs and CD133- bulk, which can be cultivated and functionally analyzed thereafter.

Patient Derived Cell Culture and Isolation of CD133+ Putative Cancer Stem Cells from Melanoma

This article describes the preparation of freshly obtained melanoma tissue into primary cell cultures, and how to remove contaminations of erythrocytes and fibroblasts from the tumor cells. Finally, we describe how CD133+ putative melanoma stem cells are sorted from the CD133- bulk using Magnetic Activated Cell Sorting (MACS).

Despite improved treatments options for melanoma available today, patients with advanced malignant melanoma still have a poor prognosis for ...

Isolation, Culture, and Imaging of Human Fetal Pancreatic Cell Clusters

For almost 30 years, scientists have demonstrated that human fetal ICCs transplanted under the kidney capsule of nude mice matured into functioning endocrine cells, as evidenced by a significant increase in circulating human C-peptide following glucose stimulation1-9. However in vitro, genesis of insulin producing cells from human fetal ICCs is low10; results reminiscent of recent experiments performed with human embryonic stem cells (hESC), a renewable source of cells that hold great promise as a potential therapeutic treatment for type 1 diabetes. Like ICCs, transplantation of partially differentiated hESC generate glucose responsive, insulin producing cells, but in vitro genesis of insulin producing cells from hESC is much less robust11-17. A complete understanding of the factors that influence the growth and differentiation of endocrine precursor cells will likely require data generated from both ICCs and hESC. While a number of protocols exist to generate insulin producing cells from hESC in vitro11-22, far fewer exist for ICCs10,23,24. Part of that discrepancy likely comes from the difficulty of working with human fetal pancreas. Towards that end, we have continued to build upon existing methods to isolate fetal islets from human pancreases with gestational ages ranging from 12 to 23 weeks, grow the cells as a monolayer or in suspension, and image for cell proliferation, pancreatic markers and human hormones including glucagon and C-peptide. ICCs generated by the protocol described below result in C-peptide release after transplantation under the kidney capsule of nude mice that are similar to C-peptide levels obtained by transplantation of fresh tissue6. Although the examples presented here focus upon the pancreatic endoderm proliferation and &#946;&#160;cell genesis, the protocol can be employed to study other aspects of pancreatic development, including exocrine, ductal, and other hormone producing cells.

A protocol to isolate, culture, and image islet cell clusters (ICCs) derived from human fetal pancreatic cells is described.&#160; The method details the steps necessary to generate ICCs from tissue, culture as monolayers or in suspension as aggregates, and image for markers of proliferation and pancreatic cell fate decisions.

For almost 30 years, scientists have demonstrated that human fetal ICCs transplanted under the kidney capsule of nude mice matured into functioning ...

Isolation, Cryopreservation and Culture of Human Amnion Epithelial Cells for Clinical Applications

Human amnion epithelial cells (hAECs) derived from term or pre-term amnion membranes have attracted attention from researchers and clinicians as a potential source of cells for regenerative medicine. The reason for this interest is evidence that these cells have highly multipotent differentiation ability, low immunogenicity, and anti-inflammatory functions. These properties have prompted researchers to investigate the potential of hAECs to be used to treat a variety of diseases and disorders in pre-clinical animal studies with much success.
hAECs have found widespread application for the treatment of a range of diseases and disorders. Potential clinical applications of hAECs include the treatment of stroke, multiple sclerosis, liver disease, diabetes and chronic and acute lung diseases. Progressing from pre-clinical animal studies into clinical trials requires a higher standard of quality control and safety for cell therapy products. For safety and quality control considerations, it is preferred that cell isolation protocols use animal product-free reagents. 
We have developed protocols to allow researchers to isolate, cryopreserve and culture hAECs using animal product-free reagents. The advantage of this method is that these cells can be isolated, characterized, cryopreserved and cultured without the risk of delivering potentially harmful animal pathogens to humans, while maintaining suitable cell yields, viabilities and growth potential. For researchers moving from pre-clinical animal studies to clinical trials, these methodologies will greatly accelerate regulatory approval, decrease risks and improve the quality of their therapeutic cell population.

We describe a protocol to isolate and culture human amnion epithelial cells (hAECs) using animal product-free reagents in accordance with current good manufacturing practices (cGMP) guidelines.

Human amnion epithelial cells (hAECs) derived from term or pre-term amnion membranes have attracted attention from researchers and clinicians as a ...

Isolation of Human Lymphatic Endothelial Cells by Multi-parameter Fluorescence-activated Cell Sorting

Lymphatic system disorders such as primary lymphedema, lymphatic malformations and lymphatic tumors are rare conditions that cause significant morbidity but little is known about their biology. Isolating highly pure human lymphatic endothelial cells (LECs) from diseased and healthy tissue would facilitate studies of the lymphatic endothelium at genetic, molecular and cellular levels. It is anticipated that these investigations may reveal targets for new therapies that may change the clinical management of these conditions. A protocol describing the isolation of human foreskin LECs and lymphatic malformation lymphatic endothelial cells (LM LECs) is presented. To obtain a single cell suspension tissue was minced and enzymatically treated using dispase II and collagenase II. The resulting single cell suspension was then labelled with antibodies to cluster of differentiation (CD) markers CD34, CD31, Vascular Endothelial Growth Factor-3 (VEGFR-3) and PODOPLANIN. Stained viable cells were sorted on a fluorescently activated cell sorter (FACS) to separate the CD34LowCD31PosVEGFR-3PosPODOPLANINPos LM LEC population from other endothelial and non-endothelial cells. The sorted LM LECs were cultured and expanded on fibronectin-coated flasks for further experimental use.

The goal of this protocol is to isolate lymphatic endothelial cells lining human lymphatic malformation cyst-like vessels and foreskins using fluorescence-activated cell sorting (FACS). Subsequent cell culturing and expansion of these cells permits a new level of experimental sophistication for genetic, proteomic, functional and cell differentiation studies.

Lymphatic system disorders such as primary lymphedema, lymphatic malformations and lymphatic tumors are rare conditions that cause significant morbidity ...

Isolation and Culture of Primary Endothelial Cells from Canine Arteries and Veins

Cardiovascular disease is studied in both human and veterinary medicine. Endothelial cells have been used extensively as an in vitro model to study vasculogenesis, (tumor) angiogenesis, and atherosclerosis. The current standard for in vitro research on human endothelial cells (ECs) is the use of Human Umbilical Vein Endothelial Cells (HUVECs) and Human Umbilical Artery Endothelial Cells (HUAECs). For canine endothelial research, only one cell line (CnAOEC) is available, which is derived from canine aortic endothelium. Although currently not completely understood, there is a difference between ECs originating from either arteries or veins. For a more direct approach to in vitro functionality studies on ECs, we describe a new method for isolating Canine Primary Endothelial Cells (CaPECs) from a variety of vessels. This technique reduces the chance of contamination with fast-growing cells such as fibroblasts and smooth muscle cells, a problem that is common in standard isolation methods such as flushing the vessel with enzymatic solutions or mincing the vessel prior to digestion of the tissue containing all cells. The technique we describe was optimized for the canine model, but can easily be utilized in other species such as human.

Novel isolation methods of primary endothelial cells from blood vessels are needed. This protocol describes a new technique that completely inverts blood vessels of interest, exposing only the endothelial side to enzymatic digestion. The resulting pure endothelial cell culture can be used to study cardiovascular diseases, disease modelling, and angiogenesis.

Cardiovascular disease is studied in both human and veterinary medicine. Endothelial cells have been used extensively as an in vitro model to study ...

Isolation of Endothelial Progenitor Cells from Healthy Volunteers and Their Migratory Potential Influenced by Serum Samples After Cardiac Surgery

Endothelial progenitor cells (EPCs) are recruited from the bone marrow under pathological conditions like hypoxia and are crucially involved in the neovascularization of ischemic tissues. The origin, classification and characterization of EPCs are complex; notwithstanding, two prominent sub-types of EPCs have been established: so-called &#34;early&#34; EPCs (subsequently referred to as early-EPCs) and late-outgrowth EPCs (late-EPCs). They can be classified by biological properties as well as by their appearance during in vitro culture. While &#34;early&#34; EPCs appear in less than a week after culture of peripheral blood-derived mononuclear cells in EC-specific media, late-outgrowth EPCs can be found after 2-3 weeks. Late-outgrowth EPCs have been recognized to be directly involved in neovascularization, mainly through their ability to differentiate into mature endothelial cells, whereas &#34;early&#34; EPCs express various angiogenic factors as endogenous cargo to promote angiogenesis in a paracrine manner. During myocardial ischemia/reperfusion (I/R), various factors control the homing of EPCs to regions of blood vessel formation.
Macrophage migration inhibitory factor (MIF) is a chemokine-like pro-inflammatory and ubiquitously expressed cytokine and was recently described to function as key regulator of EPCs migration at physiological concentrations1. Interestingly, MIF is stored in intracellular pools and can rapidly be released into the blood stream after several stimuli (e.g. myocardial infarction). 
This protocol describes a method for the reliable isolation and culture of early-EPCs from adult human peripheral blood based on CD34-positive selection with subsequent culture in medium containing endothelial growth factors on fibronectin-coated plates for use in in vitro migration assays against serum samples of cardiac surgical patients. Furthermore, the migratory influence of MIF on chemotaxis of EPCs compared to other well-known angiogenesis-stimulating cytokines is demonstrated.

Endothelial progenitor cells (EPCs) are crucially involved in the neovascularization of ischemic tissues. This method describes the isolation of human EPCs from peripheral blood, as well as the identification of their migratory potential against serum samples of cardiac surgical patients.

Endothelial progenitor cells (EPCs) are recruited from the bone marrow under pathological conditions like hypoxia and are crucially involved in the ...

Preparation and In Vitro Characterization of Magnetized miR-modified Endothelial Cells

To date, the available surgical and pharmacological treatments for cardiovascular diseases (CVD) are limited and often palliative. At the same time, gene and cell therapies are highly promising alternative approaches for CVD treatment. However, the broad clinical application of gene therapy is greatly limited by the lack of suitable gene delivery systems. The development of appropriate gene delivery vectors can provide a solution to current challenges in cell therapy. In particular, existing drawbacks, such as limited efficiency and low cell retention in the injured organ, could be overcome by appropriate cell engineering (i.e., genetic) prior to transplantation. The presented protocol describes the efficient and safe transient modification of endothelial cells using a polyethyleneimine superparamagnetic magnetic nanoparticle (PEI/MNP)-based delivery vector. Also, the algorithm and methods for cell characterization are defined. The successful intracellular delivery of microRNA (miR) into human umbilical vein endothelial cells (HUVECs) has been achieved without affecting cell viability, functionality, or intercellular communication. Moreover, this approach was proven to cause a strong functional effect in introduced exogenous miR. Importantly, the application of this MNP-based vector ensures cell magnetization, with accompanying possibilities of magnetic targeting and non-invasive MRI tracing. This may provide a basis for magnetically guided, genetically engineered cell therapeutics that can be monitored non-invasively with MRI.

Preparation and In Vitro Characterization of Magnetized miR-modified Endothelial Cells

This manuscript describes the efficient, non-viral delivery of miR to endothelial cells by a PEI/MNP vector and their magnetization. Thus, in addition to genetic modification, this approach allows for magnetic cell guidance and MRI detectability. The technique can be used to improve the characteristics of therapeutic cell products.

To date, the available surgical and pharmacological treatments for cardiovascular diseases (CVD) are limited and often palliative. At the same time, gene ...

Assessment of the Anticoagulant and Anti-inflammatory Properties of Endothelial Cells Using 3D Cell Culture and Non-anticoagulated Whole Blood

In vivo, endothelial cells are crucial for the natural anticoagulation of circulating blood. Consequently, endothelial cell activation leads to blood coagulation. This phenomenon is observed in many clinical situations, like organ transplantation in the presence of pre-formed anti-donor antibodies, including xenotransplantation, as well as in ischemia/reperfusion injury. In order to reduce animal experimentation according to the 3R standards (reduction, replacement and refinement), in vitro models to study the effect of endothelial cell activation on blood coagulation would be highly desirable. However, common flatbed systems of endothelial cell culture provide a surface-to-volume ratio of 1 - 5 cm2 of endothelium per mL of blood, which is not sufficient for natural, endothelial-mediated anticoagulation. Culturing endothelial cells on microcarrier beads may increase the surface-to-volume ratio to 40 - 160 cm2/mL. This increased ratio is sufficient to ensure the &#34;natural&#34; anticoagulation of whole blood, so that the use of anticoagulants can be avoided. Here an in vitro microcarrier-based system is described to study the effects of genetic modification of porcine endothelial cells on coagulation of whole, non-anticoagulated human blood. In the described assay, primary porcine aortic endothelial cells, either wild type (WT) or transgenic for human CD46 and thrombomodulin, were grown on microcarrier beads and then exposed to freshly drawn non-anticoagulated human blood. This model allows for the measurement and quantification of cytokine release as well as activation markers of complement and coagulation in the blood plasma. In addition, imaging of activated endothelial cell and deposition of immunoglobulins, complement- and coagulation proteins on the endothelialized beads were performed by confocal microscopy. This assay can also be used to test drugs which are supposed to prevent endothelial cell activation and, thus, coagulation. On top of its potential to reduce the number of animals used for such investigations, the described assay is easy to perform and consistently reproducible.

We present an in vitro model which allows the study and analysis of coagulation in whole, non-anticoagulated blood. Anticoagulation in the system depends on the natural anticoagulation effect of healthy endothelial cells and endothelial cell activation will result in clotting.

In vivo, endothelial cells are crucial for the natural anticoagulation of circulating blood. Consequently, endothelial cell activation leads to blood ...

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations

Many hamstring injuries that occur during physical activity occur while the muscles are lengthening, during eccentric hamstring muscle actions. Opposite of these eccentric hamstring actions are concentric quadriceps actions, where the larger and likely stronger quadriceps straighten the knee. Therefore, to stabilize the lower limbs during movement, the hamstrings must eccentrically combat against the strong knee-straightening torque of the quadriceps. As such, eccentric hamstring strength expressed relative to concentric quadricep strength is commonly referred to as the &#34;functional ratio&#34; as most movements in sports require simultaneous concentric knee extension and eccentric knee flexion. To increase the strength, resiliency, and functional performance of the hamstrings, it is necessary to test and train the hamstrings at different eccentric speeds. The main purpose of this work is to provide instructions for measuring and interpreting eccentric hamstring strength. Techniques for measuring the functional ratio using isokinetic dynamometry are provided and sample data will be compared. Additionally, we briefly describe how to address hamstring strength deficiencies or unilateral strength differences using exercises that specifically focus on increasing eccentric hamstring strength.

The hamstrings are a group of muscles that are sometimes problematic for athletes, resulting in soft tissue injury in the lower limbs. To prevent such injuries, functional training of the hamstrings requires intensive eccentric contractions. Additionally, hamstring function should be tested in relation to quadricep function at different contraction speeds.

Many hamstring injuries that occur during physical activity occur while the muscles are lengthening, during eccentric hamstring muscle actions. Opposite ...