Name: human saphenous vein endothelial cell isolation and exposure to controlled levels of shear stress and stretch
Uploaded: 2023-04-21T14:35:00
Description: Watch this Scientific Journal Video about Human Saphenous Vein Endothelial Cell Isolation and Exposure to Controlled Levels of Shear Stress and Stretch at JoVE.com

JEK is supported by grants from Funda&#231;&#227;o de Amparo &#224; Pesquisa do Estado de S&#227;o Paulo [FAPESP-INCT-20214/50889-7 and 2013/17368-0] and Conselho Nacional de Desenvolvimento Cient&#237;fico e Tecnol&#243;gico-CNPq (INCT-465586/2014-7 and 309179/2013-0). AAM is supported by grants from Funda&#231;&#227;o de Amparo &#224; Pesquisa do Estado de S&#227;o Paulo (FAPESP 2015/11139-5) and Conselho Nacional de Desenvolvimento Cient&#237;fico e Tecnol&#243;gico-CNPq (Universal - 407911/2021-9).

Unused segments of saphenous veins were obtained from patients undergoing aortocoronary bypass surgery at the Heart Institute (InCor), University of S&#227;o Paulo Medical School. All individuals gave informed consent to participate in the study, which was reviewed and approved by the local ethics committee.
1. Isolation, culture, and characterization of primary human saphenous vein endothelial cells (hSVECs)
<ol>
	<li>Preparation
	<ol>
		<li>Autoclave a pair of straight or ...

<ol>
	<li>Allaire, E., Clowes, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+cell+injury+in+cardiovascular+surgery:+the+intimal+hyperplastic+response.">Endothelial cell injury in cardiovascular surgery: the intimal hyperplastic response.</a> The Annals of Thoracic Surgery. 63 (2), 582-591 (1997).</li><li>Ali, M. H., Schumacker, P. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+responses+to+mechanical+stress:+where+is+the+mechanosensor.">Endothelial responses to mechanical stress: where is the mechanosensor.</a> Critical Care Medicine. 30 (5), S198-S206 (2002).</li><li>Ward, A. O., Caputo, M., Angelini, G. D., George, S. J., Zakkar, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+and+inflammation+of+the+venous+endothelium+in+vein+graft+disease.">Activation and inflammation of the venous endothelium in vein graft disease.</a> Atherosclerosis. 265, 266-274 (2017).</li><li>Ward, A. O., 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=NF-&#954;B+inhibition+prevents+acute+shear+stress-induced+inflammation+in+the+saphenous+vein+graft+endothelium.">NF-&#954;B inhibition prevents acute shear stress-induced inflammation in the saphenous vein graft endothelium.</a> Scientific Reports. 10 (1), 15133 (2020).</li><li>Golledge, J., Turner, R. J., Harley, S. L., Springall, D. R., Powell, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circumferential+deformation+and+shear+stress+induce+differential+responses+in+saphenous+vein+endothelium+exposed+to+arterial+flow.">Circumferential deformation and shear stress induce differential responses in saphenous vein endothelium exposed to arterial flow.</a> The Journal of Clinical Investigation. 99 (11), 2719-2726 (1997).</li><li>Gir&#227;o-Silva, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+stretch+induces+endothelial+dysfunction+accompanied+by+oxidative+stress+and+actin+remodeling+in+human+saphenous+vein+endothelial+cells.">High stretch induces endothelial dysfunction accompanied by oxidative stress and actin remodeling in human saphenous vein endothelial cells.</a> Scientific Reports. 11 (1), 13493 (2021).</li><li>Ataollahi, F., 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=New+method+for+the+isolation+of+endothelial+cells+from+large+vessels.">New method for the isolation of endothelial cells from large vessels.</a> Cytotherapy. 16 (8), 1145-1152 (2014).</li><li>Torres, C., Machado, R., Lima, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometric+characterization+of+the+saphenous+veins+endothelial+cells+in+patients+with+chronic+venous+disease+and+in+patients+undergoing+bypass+surgery:+an+exploratory+study.">Flow cytometric characterization of the saphenous veins endothelial cells in patients with chronic venous disease and in patients undergoing bypass surgery: an exploratory study.</a> Heart and Vessels. 35 (1), 1-13 (2020).</li><li>Aird, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenotypic+heterogeneity+of+the+endothelium:+II.+Representative+vascular+beds.">Phenotypic heterogeneity of the endothelium: II. Representative vascular beds.</a> Circulation Research. 100 (2), 174-190 (2007).</li><li>Jambusaria, 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=Endothelial+heterogeneity+across+distinct+vascular+beds+during+homeostasis+and+inflammation.">Endothelial heterogeneity across distinct vascular beds during homeostasis and inflammation.</a> eLife. 9, e51413 (2020).</li><li>Carneiro, A. P., Fonseca-Alaniz, M. H., Dallan, L. A. O., Miyakawa, A. A., Krieger, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#946;-arrestin+is+critical+for+early+shear+stress-induced+Akt/eNOS+activation+in+human+vascular+endothelial+cells.">&#946;-arrestin is critical for early shear stress-induced Akt/eNOS activation in human vascular endothelial cells.</a> Biochemical and Biophysical Research Communications. 483 (1), 75-81 (2017).</li><li>Davis, M. E., Cai, H., Drummond, G. R., Harrison, D. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+regulates+endothelial+nitric+oxide+synthase+expression+through+c-Src+by+divergent+signaling+pathways.">Stress regulates endothelial nitric oxide synthase expression through c-Src by divergent signaling pathways.</a> Circulation Research. 89 (11), 1073-1080 (2001).</li><li>Dekker, R. 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=Prolonged+fluid+shear+stress+induces+a+distinct+set+of+endothelial+cell+genes,+most+specifically+lung+Kruppel-like+factor+(KLF2).">Prolonged fluid shear stress induces a distinct set of endothelial cell genes, most specifically lung Kruppel-like factor (KLF2).</a> Blood. 100 (5), 1689-1698 (2002).</li><li>Hamik, 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=Kruppel-like+factor+4+regulates+endothelial+inflammation.">Kruppel-like factor 4 regulates endothelial inflammation.</a> The Journal of Biological Chemistry. 282 (18), 13769-13779 (2007).</li><li>Beamish, J. A., He, P., Kottke-Marchant, K., Marchant, R. 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The saphenous vein segment should have be least 2 cm to successfully isolate hSVECs. Small segments are difficult to handle and tie the ends of the vessel to maintain the collagenase solution to isolate the cells. The reduced luminal surface area does not yield sufficient cells to expand the culture. To minimize the risk of contamination with non-ECs, the manipulation of the saphenous vein segment needs to be very gentle during the entire procedure. It is important to be careful when introducing the pipette tips into the...

Endothelial cell (EC) dysfunction is a key player in saphenous vein graft failure1,2,3,4. The sustained increase of shear stress and cyclic stretch induces the proinflammatory phenotype of human saphenous vein endothelial cells (hSVECs)3,4,5,6. The underlying molecular pathways are still not fully understood, and standardized protocols for in vitro studies may leverage the efforts for novel insights in the area. Here, we describe a simple protocol to isolate, characterize, and expand hSVECs and how to expose them to variable levels of shear stress and cyclic stretch, mimicking the venous and arterial hemodynamic conditions.
hSVECs are isolated by collagenase incubation and can be used up to passage 8. This protocol requires less manipulation of the vessel compared with the other available protocols7, which reduces contamination with smooth muscle cells and fibroblasts. On the other hand, it requires a larger vessel segment of at least 2 cm to have efficient EC extraction. In the literature, it has been reported that ECs from large vessels can also be obtained by mechanical removal7,8. Although effective, the physical approach has the disadvantages of low EC yield and higher fibroblast contamination. To increase the purity, extra steps are needed using magnetic beads or cell sorting, increasing the cost of the protocol due to the acquisition of beads and antibodies7,8. The enzymatic method has faster and better outcomes regarding EC purity and viability7,8.
The most frequently used ECs to study endothelial dysfunction are human umbilical vein endothelial cells (HUVECs). It is known that the EC phenotype changes in different vascular beds, and it is essential to develop methods that represent the vessel under investigation9,10. In this respect, the establishment of a protocol to isolate a hSVEC and culture it under mechanical stress is a valuable tool to understand the contribution of hSVEC dysfunction in vein graft disease.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.25% Trypsin-0.02% EDTA solution</td>
			<td>Gibco</td>
			<td>25200072</td>
			<td></td>
		</tr>
		<tr>
			<td>15 &#181; slide I 0.4 Luer&#160;</td>
			<td>Ibidi</td>
			<td>80176</td>
			<td></td>
		</tr>
		<tr>
			<td>4&#39;,6-Diamidino-2-Phenylindole, Dilactate (DAPI)</td>
			<td>Thermo Fisher Scientific</td>
			<td>D3571</td>
			<td></td>
		</tr>
		<tr>
			<td>6-wells equibiaxial loading station of 25 mm&#160;</td>
			<td>Flexcell International Corporation</td>
			<td>LS-3000B25.VJW</td>
			<td></td>
		</tr>
		<tr>
			<td>8-well chamber slide with removable well</td>
			<td>Thermo Fisher Scientific</td>
			<td>154453</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic Acid (Glacial)</td>
			<td>Millipore</td>
			<td>100063</td>
			<td></td>
		</tr>
		<tr>
			<td>Acrylic sheet 1 cm thick</td>
			<td>Plexiglass</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-CD31 antibody</td>
			<td>Abcam</td>
			<td>ab24590</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-CD31, FITC antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>MHCD3101</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-VE-cadherin antibody</td>
			<td>Cell Signaling</td>
			<td>2500</td>
			<td></td>
		</tr>
		<tr>
			<td>Bioflex plates collagen I</td>
			<td>Flexcell International Corporation</td>
			<td>BF3001C</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin solution</td>
			<td>Sigma-Aldrich</td>
			<td>A8412</td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton suture EP 3.5 15 x 45 cm</td>
			<td>Brasuture</td>
			<td>AP524</td>
			<td></td>
		</tr>
		<tr>
			<td>Cyclophilin forward primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>Cyclophilin reverse primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO)</td>
			<td>Sigma-Aldrich</td>
			<td>D4540</td>
			<td></td>
		</tr>
		<tr>
			<td>EBM-2 basal medium</td>
			<td>Lonza</td>
			<td>CC3156</td>
			<td></td>
		</tr>
		<tr>
			<td>EGM-2 SingleQuots supplements</td>
			<td>Lonza</td>
			<td>CC4176</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)</td>
			<td>Thermo Fisher Scientific</td>
			<td>2657-029</td>
			<td></td>
		</tr>
		<tr>
			<td>Flexcell FX-5000 tension system</td>
			<td>Flexcell International Corporation</td>
			<td>FX-5000T</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluoromount aqueous mounting medium</td>
			<td>Sigma-Aldrich</td>
			<td>F4680</td>
			<td></td>
		</tr>
		<tr>
			<td>Gelatin from porcine skin</td>
			<td>Sigma-Aldrich</td>
			<td>G2500</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sigma-Aldrich</td>
			<td>G5516</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-Mouse IgG Alexa Fluor 488</td>
			<td>Thermo Fisher Scientific</td>
			<td>A11001</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-Rabbit IgG Alexa Fluor 488</td>
			<td>Thermo Fisher Scientific</td>
			<td>A11008</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin sodium from porcine intestinal mucosa 5000 IU/mL</td>
			<td>Blau Farmac&#234;utica</td>
			<td>SKU 68027</td>
			<td></td>
		</tr>
		<tr>
			<td>Ibidi pump system (Pump + Fluidic Unit)</td>
			<td>Ibidi</td>
			<td>10902</td>
			<td></td>
		</tr>
		<tr>
			<td>KLF2 forward primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>KLF2 reverse primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>KLF4 forward primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>KLF4 reverse primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>NOA 280 nitric oxide analyzer</td>
			<td>Sievers Instruments</td>
			<td>NOA-280i-1</td>
			<td></td>
		</tr>
		<tr>
			<td>NOS3 forward primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>NOS3 reverse primer</td>
			<td>Thermo Fisher Scientific</td>
			<td>Custom designed</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde (PFA)</td>
			<td>Sigma-Aldrich</td>
			<td>158127</td>
			<td></td>
		</tr>
		<tr>
			<td>Perfusion set 15 cm, ID 1.6 mm, red, 10 mL reservoirs</td>
			<td>Ibidi</td>
			<td>10962</td>
			<td></td>
		</tr>
		<tr>
			<td>Phalloidin - Alexa Fluor 488</td>
			<td>Thermo Fisher Scientific</td>
			<td>A12379</td>
			<td></td>
		</tr>
		<tr>
			<td>Phalloidin - Alexa Fluor 568</td>
			<td>Thermo Fisher Scientific</td>
			<td>A12380</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffered saline (PBS), pH 7.4</td>
			<td>Thermo Fisher Scientific</td>
			<td>10010031</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium Iodide</td>
			<td>Sigma-Aldrich</td>
			<td>221945</td>
			<td></td>
		</tr>
		<tr>
			<td>QuanTitec SYBR green PCR kit</td>
			<td>Qiagen</td>
			<td>204143</td>
			<td></td>
		</tr>
		<tr>
			<td>QuantStudio 12K flex platform&#160;</td>
			<td>Applied Biosystems</td>
			<td>4471087</td>
			<td></td>
		</tr>
		<tr>
			<td>RNeasy micro kit&#160;</td>
			<td>Quiagen</td>
			<td>74004</td>
			<td></td>
		</tr>
		<tr>
			<td>Slide glass (24 mm x 60 mm)</td>
			<td>Knittel Glass</td>
			<td>VD12460Y1D.01</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium nitrite</td>
			<td>Sigma-Aldrich</td>
			<td>31443</td>
			<td></td>
		</tr>
		<tr>
			<td>SuperScript IV first-strand synthesis system</td>
			<td>Thermo Fisher Scientific</td>
			<td>18091200</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>T8787</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue stain 0.4%</td>
			<td>Gibco</td>
			<td>15250-061</td>
			<td></td>
		</tr>
		<tr>
			<td>Type II collagenase from Clostridium histolyticum</td>
			<td>Sigma-Aldrich</td>
			<td>C6885</td>
			<td></td>
		</tr>
	</tbody>
</table>

human saphenous vein endothelial cell isolation and exposure to controlled levels of shear stress and stretch

Coronary artery bypass graft (CABG) surgery is a procedure to revascularize ischemic myocardium. Saphenous vein remains used as a CABG conduit despite the reduced long-term patency compared to arterial conduits. The abrupt increase of hemodynamic stress associated with the graft arterialization results in vascular damage, especially the endothelium, that may influence the low patency of the saphenous vein graft (SVG). Here, we describe the isolation, characterization, and expansion of human saphenous vein endothelial cells (hSVECs). Cells isolated by collagenase digestion display the typical cobblestone morphology and express endothelial cell markers CD31 and VE-cadherin. To assess the mechanical stress influence, protocols were used in this study to investigate the two main physical stimuli, shear stress and stretch, on arterialized SVGs. hSVECs are cultured in a parallel plate flow chamber to produce shear stress, showing alignment in the direction of the flow and increased expression of KLF2, KLF4, and NOS3. hSVECs can also be cultured in a silicon membrane that allows controlled cellular stretch mimicking venous (low) and arterial (high) stretch. Endothelial cells' F-actin pattern and nitric oxide (NO) secretion are modulated accordingly by the arterial stretch. In summary, we present a detailed method to isolate hSVECs to study the influence of hemodynamic mechanical stress on an endothelial phenotype.

Typically, adhered ECs can be observed 3-4 days after extraction. hSVECs initially form clusters of cells and display a typical &#34;cobblestone&#34; morphology (Figure 1B). They express the EC markers CD31 (Figure 1C,D) and VE-cadherin (Figure 1D). hSVECs can be easily propagated on a non-coated treated cell culture dish, and they retain the endothelial phenotype in culture up to eight passages.
<p class="jove_...

Watch this Scientific Journal Video about Human Saphenous Vein Endothelial Cell Isolation and Exposure to Controlled Levels of Shear Stress and Stretch at JoVE.com

Human Saphenous Vein Endothelial Cell Isolation and Exposure to Controlled Levels of Shear Stress and Stretch

We describe a protocol to isolate and culture human saphenous vein endothelial cells (hSVECs). We also provide detailed methods to produce shear stress and stretch to study mechanical stress in hSVECs.

Coronary artery bypass graft (CABG) surgery is a procedure to revascularize ischemic myocardium. Saphenous vein remains used as a CABG conduit despite the ...

The saphenous vein is suddenly exposed to arterial conditions after coronary artery bypass surgery. Understanding its adaptation response to mechanical stress may help designing therapeutic tools to prevent vein graft failure. This endothelial cell isolation protocol is very simple and only requires incubation with collagenase.With minimal vessel manipulation, this results in reduced contamination with smooth muscle cells and fibroblasts. The protocol for isolating human SVECs and culture them under shear stress and cyclic stretch is essential to understand the contribution of mechanical forces in endothelial cell dysfunction associated with saphenous vein graft failure. Prior endothelial cell culture is very demanding in terms of cell media supplements.It is mandatory to add growth factors to successfully isolate a culture, the human SVECs. For isolating primary human saphenous vein endothelial cells or human SVECs, collect at least a two-to three-centimeter long saphenous vein segment. Working under a sterile laminar flow hood, transfer the vein segment to a Petri dish filled with pre-warmed PBS.To remove all the blood from inside the lumen, insert a pipette tip attached to a pipette and filled with PBS into one end of the vein and gently flush it. Flush it until the washing flow becomes completely clear. Then close one end of the vein with a sterile cotton suture.Carefully fill the vessel with one milligram per milliliter collagenase type 2 solution and close the other end of the vessel with a cotton suture. Incubate the vessel with collagenase solution in a humidified atmosphere of 5%carbon dioxide at 37 degrees celsius for one hour. Then cut one end of the vessel over a 15-milliliter tube to collect the collagenase solution before cutting the other end.Flush the luminal surface with one to two milliliters of PBS to collect all the detached endothelial cells inside the tube with collagenase. Centrifuge the tube at 400G in room temperature for five minutes. After removing the supernatant, re-suspend the cell pellet in three to four milliliters of complete endothelial cell medium containing an additional heparin solution.Plate the cells in a 60-millimeter cell culture dish pre-coated with 3%weight per volume gelatin. Incubate the cells in a humidified atmosphere for four days without changing the medium. After that, change the medium every other day without adding the heparin supplementation.Examine the plate under the microscope to ensure that the red blood cells were removed. After one to four days post extraction, depending on the size and diameter of the vein segment, visualize the human SVECs by phase contrast microscopy to evaluate the degree of confluence and their cobblestone morphology. Continue changing the media every two days until the cells reach 70%to 80%confluency.Coat the flow chamber slide with 0.1%weight per volume gelatin and incubate for at least 30 minutes at 37 degrees Celsius. To equilibrate the fluidic unit and the sterile perfusion set having 10 millimeter reservoirs, incubate those overnight in a humidified atmosphere. For the shear stress experiment, seed 200, 000 endothelial cells suspended in 100 microliters of culture medium into the gelatin-coated flow chamber slide.For attaching the cells to the culture surface, incubate the cells for four hours. Place the perfusion set on the fluidic unit. Fill in the reservoirs and the perfusion set with about 12 milliliters of pre-warmed complete endothelial cell medium.Remove air bubbles from the perfusion set to equilibrate the level of both reservoirs at five milliliters. Place the fluidic unit on the mounted perfusion set without the chamber slide in the incubator and connect its electric cable to the computer-regulated pump. By running the pre-defined protocol in the pump control software, remove all air bubbles from the reservoirs and the perfusion set.Take the fluidic unit with the mounted perfusion set to the laminar flow hood and attach the slides having a confluence cell monolayer. After placing the whole unit with the slides in the incubator, connect its electrical cable to the pump. In the pump control software, adjust the fluidic unit setup by selecting the type of slide and setting the viscosity of the medium.In flow parameters, enter the shear stress value and set the cycle duration and flow type. Then click the play button to start the experiment. Remember to maintain the slide with cells treated with the same media without exposure to flow as static controls.Apply silicone-based lubricant to the tops and sides of the 25-millimeter 6-well equibiaxial loading station. Seed 400, 000 cells suspended in three milliliters to each well of the 6-well flexible-bottomed culture plates coated with collagen one. Incubate the cells in humidified air until they reach 100%confluency.Prior to starting the stretch protocol, wash the cells once with pre-warmed PBS and add three milliliters of fresh culture medium per well. Insert the base plate with all lubricated loading stations in the incubator and appropriately connect the tubing with the controller equipment of the tension cell stretching bioreactor system. Attach each culture plate to one red gasket provided by the bioreactor system.Then put them into the base plate in the incubator. Place all four culture plates in the base plate to achieve proper vacuum and stretching load. Turn on the controller equipment and the computer system.Open the FlexCell control software and configure the desired regimen including the percentage of elongation, waveform shape, frequency, and time. Save the regimen. Turn on the vacuum system, then select the regimen and click start on the computer screen to run the stretching.Check that the silicone membrane is moving and stretching the cells. The adhered endothelial cells could be observed 4 to 10 days after the extraction. They initially form cell clusters displaying a typical cobblestone morphology.They expressed the EC markers CD31 and VE-cadherin. The hSVECs when cultured under shear stress aligned in the direction of the flow. The shear stress of 20 dynes per square centimeter for 72 hours induce the expression of typical mechanosensitive genes, KLF2, KLF4, and NOS3, indicating the effectiveness of the shear stimulus.The cyclic stretch outcome depended on the intensity applied to the human SVECs. Cells under low stretch showed a cortical F-actin pattern similar to static cells. Without change in the nitric oxide release for up to 72 hours, our arterial levels of stretch remodeled the actin cytoskeleton after 24 hours and decreased NO release after 72 hours.Besides mechanical stress studies, researchers can use the isolated cells to perform various methods to expand knowledge of endothelial cell function and dysfunction. Following the demonstrated protocol, it's possible to study any other type of endothelial cells under shear stress and stretch.

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Research

JoVE Journal

Medicine

Isolation of Mouse Respiratory Epithelial Cells and Exposure to Experimental Cigarette Smoke at Air Liquid Interface

Pulmonary epithelial cells can be isolated from the respiratory tract of mice and cultured at air-liquid interface (ALI) as a model of differentiated respiratory epithelium. A protocol is described for isolating and exposing these cells to mainstream cigarette smoke (CS), in order to study epithelial cell responses to CS exposure. The protocol consists of three parts: the isolation of airway epithelial cells from mouse trachea, the culturing of these cells at air-liquid interface (ALI) as fully differentiated epithelial cells, and the delivery of calibrated mainstream CS to these cells in culture. The ALI culture system allows the culture of respiratory epithelia under conditions that more closely resemble their physiological setting than ordinary liquid culture systems. The study of molecular and lung cellular responses to CS exposure is a critical component of understanding the impact of environmental air pollution on human health. Research findings in this area may ultimately contribute towards understanding the etiology of chronic obstructive pulmonary disease (COPD), and other tobacco-related diseases, which represent major global health problems.

Pulmonary epithelial cells can be isolated from the respiratory tract of mice and cultured at air-liquid interface as a model of differentiated respiratory epithelium. A protocol is described for isolating, culturing and exposing these cells to mainstream cigarette smoke, in order to study molecular responses to this environmental toxin.

Pulmonary epithelial cells can be isolated from the respiratory tract of mice and cultured at air-liquid interface (ALI) as a model of differentiated ...

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 ...

A Modified In vitro Invasion Assay to Determine the Potential Role of Hormones, Cytokines and/or Growth Factors in Mediating Cancer Cell Invasion

Blood serum serves as a chemoattractant towards which cancer cells migrate and invade, facilitating their intravasation into microvessels. However, the actual molecules towards which the cells migrate remain elusive. This modified invasion assay has been developed to identify targets which drive cell migration and invasion. This technique compares the invasion index under three conditions to determine whether a specific hormone, growth factor, or cytokine plays a role in mediating the invasive potential of a cancer cell. These conditions include i) normal fetal bovine serum (FBS), ii) charcoal-stripped FBS (CS-FBS), which removes hormones, growth factors, and cytokines and iii) CS-FBS + molecule (denoted &#8220;X&#8221;). A significant change in cell invasion with CS-FBS as compared to FBS, indicates the involvement of hormones, cytokines or growth factors in mediating the change. Individual molecules can then be added back to CS-FBS to assay their ability to reverse or rescue the invasion phenotype. Furthermore, two or more factors can be combined to evaluate the additive or synergistic effects of multiple molecules in driving or inhibiting invasion. Overall, this method enables the investigator to determine whether hormones, cytokines, and/or growth factors play a role in cell invasion by serving as chemoattractants or inhibitors of invasion for a particular type of cancer cell or a specific mutant. By identifying specific chemoattractants and inhibitors, this modified invasion assay may help to elucidate signaling pathways that direct cancer cell invasion.

A Modified In vitro Invasion Assay to Determine the Potential Role of Hormones, Cytokines and/or Growth Factors in Mediating Cancer Cell Invasion

This video article describes a modified in vitro method to examine the role of hormones, cytokines and/or growth factors in driving cancer cell invasion.

Blood serum serves as a chemoattractant towards which cancer cells migrate and invade, facilitating their intravasation into microvessels. However, the ...

Procedure for Human Saphenous Veins Ex Vivo Perfusion and External Reinforcement

The mainstay of contemporary therapies for extensive occlusive arterial disease is venous bypass graft. However, its durability is threatened by intimal hyperplasia (IH) that eventually leads to vessel occlusion and graft failure. Mechanical forces, particularly low shear stress and high wall tension, are thought to initiate and to sustain these cellular and molecular changes, but their exact contribution remains to be unraveled. To selectively evaluate the role of pressure and shear stress on the biology of IH, an ex&#160;vivo perfusion system (EVPS) was created to perfuse segments of human saphenous veins under arterial regimen (high shear stress and high pressure). Further technical innovations allowed the simultaneous perfusion of two segments from the same vein, one reinforced with an external mesh. Veins were harvested using a no-touch technique and immediately transferred to the laboratory for assembly in the EVPS. One segment of the freshly isolated vein was not perfused (control, day 0). The two others segments were perfused for up to 7 days, one being completely sheltered with a 4 mm (diameter) external mesh. The pressure, flow velocity, and pulse rate were continuously monitored and adjusted to mimic the hemodynamic conditions prevailing in the femoral artery. Upon completion of the perfusion, veins were dismounted and used for histological and molecular analysis. Under ex&#160;vivo conditions, high pressure perfusion (arterial, mean = 100 mm Hg) is sufficient to generate IH and remodeling of human veins. These alterations are reduced in the presence of an external polyester mesh.

Procedure for Human Saphenous Veins Ex Vivo Perfusion and External Reinforcement

The mechanisms leading to the development of intimal hyperplasia (IH) and vein graft failure are still poorly understood. This study describes an ex&#160;vivo system to perfuse human veins under controlled flow and pressure. Furthermore the efficiency of external mesh reinforcement to limit the development of IH was evaluated.

The mainstay of contemporary therapies for extensive occlusive arterial disease is venous bypass graft. However, its durability is threatened by intimal ...

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 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.

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 ...

Vein Interposition Model: A Suitable Model to Study Bypass Graft Patency

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. Research models for bypass graft failure are essential for a better understanding of pathobiological and pathophysiological processes during graft patency loss. Large animal models, such as pigs or sheep, resemble human anatomical structures but require special facilities and equipment. This video describes a rat vein interposition model to investigate vein graft patency loss. Rats are inexpensive and easy to handle. Compared to mouse models, the convenient size of rats permits better operability and enables a sufficient amount of material to be obtained for further diverse analysis. In brief, the inferior epigastric vein of a donor rat is harvested and used to replace a segment of the femoral artery. Anastomosis is conducted via single stitches and sealed with fibrin glue. Graft patency can be monitored non-invasively using duplex sonography. Myointimal hyperplasia, which is the main cause for graft patency loss, develops progressively over time and can be calculated from histological cross sections.

This video demonstrates a model to study the development of myointimal hyperplasia after venous interposition surgery in rats.

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. ...

Synergizing Antegrade Endoscopic with Bridging Vein Harvesting for Improvement of Great Saphenous Vein Graft Quality from the Lower Leg

Antegrade endoscopic harvesting of autografts for bypass grafting may be an optimal strategy addressing excellent graft quality and reduced post-operative wound complications. This standardized protocol for antegrade endoscopic vein harvesting (EVH) from the lower leg has the potential to be introduced to routine coronary artery bypass grafting (CABG). Patients undergoing CABG surgery are positioned on a surgical table with two additional foam rollers below the extended legs, enabling antegrade EVH from the lower leg. Following minimally invasive surgical access through a bridging vein harvest technique, an endoscopic optical dissector is inserted antegrade into the wound. The main vessel and side branches are dissected under continuous optical control of vein quality status and the working channel. After, an endoscopic optical retractor is inserted with an internal bipolar electrocoagulation device for precise, safe, and tissue-protective interruption of side branches. After release of the vein, the vessel is cut off at the proximal and distal ends under optical control, retrieved from the wound, then cannulated and flushed with heparinized saline. Finally, all side branches of the vein graft are double-clipped. Vascular histology is analyzed in a randomized selection of vein samples. After applying this standardized EVH protocol, the learning curve was shown to be steep, and graft quality was sufficient for coronary artery bypass grafting in every case. There was no conversion to surgical harvesting and low risks for tissue damage and bleeding. Leg positioning and synergizing EVH with bridging vein harvesting improved procedural success and vein graft quality. In our hands, antegrade EVH from the lower leg was feasible, demonstrating straightforward graft dissection as well as adequate macroscopic and microscopic graft quality with preserved endothelial integrity. In conclusion, the introduced technique is safe, shows excellent vein autograft quality, and illustrates feasibility for elective and urgent isolated CABG and combined CABG scenarios.

Presented here is a protocol for antegrade endoscopic vein harvesting from the lower leg, which can safely be introduced in routine coronary artery bypass grafting. Vein grafts present excellent graft quality following this standardized protocol with positioning of the legs, minimally invasive access to the vein, and antegrade endoscopic vein harvesting.

Antegrade endoscopic harvesting of autografts for bypass grafting may be an optimal strategy addressing excellent graft quality and reduced post-operative ...

Isolation and Profiling of Human Primary Mesenteric Arterial Endothelial Cells at the Transcriptome Level

Endothelial cells (ECs) are crucial for vascular and whole-body function through their dynamic response to environmental cues. Elucidating the transcriptome and epigenome of ECs is paramount to understanding their roles in development, health, and disease, but is limited in the availability of isolated primary cells. Recent technologies have enabled the high-throughput profiling of EC transcriptome and epigenome, leading to the identification of previously unknown EC cell subpopulations and developmental trajectories. While EC cultures are a useful tool in the exploration of EC function and dysfunction, the culture conditions and multiple passages can introduce external variables that alter the properties of native EC, including morphology, epigenetic state, and gene expression program. To overcome this limitation, the present paper demonstrates a method of isolating human primary ECs from donor mesenteric arteries aiming to capture their native state. ECs in the intimal layer are dissociated mechanically and biochemically with the use of particular enzymes. The resultant cells can be directly used for bulk RNA or single-cell RNA-sequencing or plated for culture. In addition, a workflow is described for the preparation of human arterial tissue for spatial transcriptomics, specifically for a commercially available platform, although this method is also suitable for other spatial transcriptome profiling techniques. This methodology can be applied to different vessels collected from a variety of donors in health or disease states to gain insights into EC transcriptional and epigenetic regulation, a pivotal aspect of endothelial cell biology.

The protocol describes the isolation, culture, and profiling of endothelial cells from human mesenteric artery. Additionally, a method is provided to prepare human artery for spatial transcriptomics. Proteomics, transcriptomics, and functional assays can be performed on isolated cells. This protocol can be repurposed for any medium- or large-size artery.

Endothelial cells (ECs) are crucial for vascular and whole-body function through their dynamic response to environmental cues. Elucidating the ...

Occlusion of the Great and Small Saphenous Vein Using Copolymeric Glue Based on N-Butyl Cyanoacrylate and Methacryloxy Sulfolane

We present the preliminary results of a longitudinal observational study aimed at evaluating the effectiveness and safety at different short- and long-term follow-ups of vascular occlusion of the great saphenous vein (GSV) and small saphenous vein (SSV) affected by severe pathological reflux, using an innovative modified cyanoacrylate surgical glue composed of N-butyl cyanoacrylate and methacryloxy sulfolane (NBCA+MS). Ninety patients, prospectively recruited for 1 year, underwent the study with EcoColor-Doppler (ECD) to evaluate the maximum diameters of the GSV and SSV in the orthostatic position and the reflux time (RT). An RT greater than 0.5 s was considered pathologic. Clinical, etiology, anatomy, and pathophysiology (CEAP) assessment was used for the complete evaluation of each patient in the study. All the patients were treated by NBCA+MS glue to obtain vein occlusion and observed before treatment (baseline; T0), within 6 h after treatment (T1), 1 month after treatment (T2), 3 months after treatment (T3), 6 months after treatment (T4), and 1 year after treatment (T5). Chi-square (&#967;) analysis was performed to evaluate the effectiveness and safety of the treatment. All the patients participated in the entire duration of the study. Complete occlusion was maintained in 100% of patients at T1, 98.9% at T2 and T3, and 97.8% at T4 and T5 (p &lt; 0.001). None of the patients suffered from post-surgical thrombosis. No blue hyperpigmentation, or paresthesia was observed during the entire observation period. Immediately after treatment, 7.7% of patients needed painkillers; 1 week after treatment, 100% of patients returned to normal life. Vascular occlusion of the great or small saphenous vein using NBCA+MS glue is a safe procedure with persistent benefits after a 1 year follow-up. This procedure can be performed with local anesthesia, allowing a quick return to normal life. Thanks to its low invasiveness, the treatment is not painful.

Here, we present a protocol to treat the great saphenous vein (GSV) and the small saphenous vein (SSV) affected by severe pathological reflux, using an original sclerosing and embolizing cyanoacrylate-based glue composed of N-butyl cyanoacrylate and methacryloxy sulfolane (NBCA+MS).