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. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+regulation+of+contractile+smooth+muscle+cell+phenotype:+implications+for+vascular+tissue+engineering.">Molecular regulation of contractile smooth muscle cell phenotype: implications for vascular tissue engineering.</a> Tissue Engineering. Part B, Reviews. 16 (5), 467-491 (2010).</li></ol>

The authors have no conflicts of interest to disclose.

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

757 visualizações.  Universidade de Sao Paulo. A veia safena é subitamente exposta a condições arteriais após cirurgia de revascularização miocárdica. A compreensão de sua resposta adaptativa ao estresse mecânico pode auxiliar no desenho de ferramentas terapêuticas para prevenir a falência do enxerto venoso. Este protocolo de isolamento de células endoteliais é muito simples e requer apenas incubação com colagenase.Com manipulação mínima do vaso, isso resulta em menor contaminação com células musculares lisas e...