Name: in vitro method to control concentrations of halogenated gases in cultured alveolar epithelial cells
Uploaded: 2018-10-23T14:30:00
Description: Watch this Scientific Journal Video about In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells at JoVE.com

The authors acknowledge the Auvergne Regional Council (&#34;Programme Nouveau Chercheur de la R&#233;gion Auvergne&#34; 2013) and the French Agence Nationale de la Recherche and the Direction G&#233;n&#233;rale de L&#39;Offre de Soins (&#34;Programme de Recherche Translationnelle en Sant&#233;&#34; ANR-13-PRTS-0010) for the grants. The funders had no influence in the study design, conduct, and analysis or in the preparation of this article.

1. Culture of Alveolar Epithelial Cells (hAELVi)
<ol>
	<li>Thawing
	<ol>
		<li>Pipette 4 mL of cultivation ready-to-use human alveolar epithelial (huAEC) medium in a 15 mL plastic tube and quickly thaw the vial in a preheated water bath (37 &#176;C).</li>
		<li>Transfer the thawed cell suspension to a 15 mL plastic tube containing 4 mL of the medium before centrifuging the tube at 200 x g for 5 min.</li>
		<li>Aspirate the supernatant and resuspend the cell pellet with 5 mL of the cultivation medium. Then, transfer the...

<ol>
	<li>Bellani, G., Laffey, J. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiology,+Patterns+of+Care,+and+Mortality+for+Patients+With+Acute+Respiratory+Distress+Syndrome+in+Intensive+Care+Units+in+50+Countries.">Epidemiology, Patterns of Care, and Mortality for Patients With Acute Respiratory Distress Syndrome in Intensive Care Units in 50 Countries.</a> JAMA:T Journal of the American Medical Association. 315 (8), 788-800 (2016).</li><li>Thompson, B. T., Chambers, R. C., Liu, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+Respiratory+Distress+Syndrome.">Acute Respiratory Distress Syndrome.</a> The New England Journal of Medicine. 377 (6), 562-572 (2017).</li><li>Weiser, T. G., Regenbogen, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+estimation+of+the+global+volume+of+surgery:+a+modelling+strategy+based+on+available+data.">An estimation of the global volume of surgery: a modelling strategy based on available data.</a> The Lancet. (9633), 139-144 (2008).</li><li>Khuri, S. F., Henderson, W. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determinants+of+long-term+survival+after+major+surgery+and+the+adverse+effect+of+postoperative+complications.">Determinants of long-term survival after major surgery and the adverse effect of postoperative complications.</a> Annals of Surgery. 242 (3), 341-343 (2005).</li><li>De Conno, E., Steurer, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anesthetic-induced+improvement+of+the+inflammatory+response+to+one-lung+ventilation.">Anesthetic-induced improvement of the inflammatory response to one-lung ventilation.</a> Anesthesiology. 110 (6), 1316-1326 (2009).</li><li>Fu, H., Sun, M., Miao, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+different+concentrations+of+isoflurane+pretreatment+on+respiratory+mechanics,+oxygenation+and+hemodynamics+in+LPS-induced+acute+respiratory+distress+syndrome+model+of+juvenile+piglets.">Effects of different concentrations of isoflurane pretreatment on respiratory mechanics, oxygenation and hemodynamics in LPS-induced acute respiratory distress syndrome model of juvenile piglets.</a> Experimental Lung Research. 41 (8), 415-421 (2015).</li><li>Reutershan, J., Chang, D., Hayes, J. K., Ley, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protective+effects+of+isoflurane+pretreatment+in+endotoxin-induced+lung+injury.">Protective effects of isoflurane pretreatment in endotoxin-induced lung injury.</a> Anesthesiology. (3), 511-517 (2006).</li><li>Uhlig, C., Bluth, 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=Effects+of+Volatile+Anesthetics+on+Mortality+and+Postoperative+Pulmonary+and+Other+Complications+in+Patients+Undergoing+Surgery:+A+Systematic+Review+and+Meta-analysis.">Effects of Volatile Anesthetics on Mortality and Postoperative Pulmonary and Other Complications in Patients Undergoing Surgery: A Systematic Review and Meta-analysis.</a> Anesthesiology: The Journal of the American Society of Anesthesiologists. 124 (6), 1230-1245 (2016).</li><li>Li, Q. F., Zhu, Y. S., Jiang, H., Xu, H., Sun, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isoflurane+preconditioning+ameliorates+endotoxin-induced+acute+lung+injury+and+mortality+in+rats.">Isoflurane preconditioning ameliorates endotoxin-induced acute lung injury and mortality in rats.</a> Anesthesia and Analgesia. (5), 1591-1597 (2009).</li><li>Voigtsberger, S., Lachmann, R. 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=Sevoflurane+ameliorates+gas+exchange+and+attenuates+lung+damage+in+experimental+lipopolysaccharide-induced+lung+injury.">Sevoflurane ameliorates gas exchange and attenuates lung damage in experimental lipopolysaccharide-induced lung injury.</a> Anesthesiology. (6), 1238-1248 (2009).</li><li>Englert, J. A., Macias, A. 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=Isoflurane+Ameliorates+Acute+Lung+Injury+by+Preserving+Epithelial+Tight+Junction+Integrity.">Isoflurane Ameliorates Acute Lung Injury by Preserving Epithelial Tight Junction Integrity.</a> Anesthesiology. (2), 377-388 (2015).</li><li>Jabaudon, M., Boucher, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sevoflurane+for+Sedation+in+ARDS:+A+Randomized+Controlled+Pilot+Study.">Sevoflurane for Sedation in ARDS: A Randomized Controlled Pilot Study.</a> American Journal of Respiratory and Critical. , (2016).</li><li>Blondonnet, R., Audard, 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=RAGE+inhibition+reduces+acute+lung+injury+in+mice.">RAGE inhibition reduces acute lung injury in mice.</a> Scientific Reports. 7 (1), (2017).</li><li>Jabaudon, M., Blondonnet, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soluble+Receptor+for+Advanced+Glycation+End-Products+Predicts+Impaired+Alveolar+Fluid+Clearance+in+Acute+Respiratory+Distress+Syndrome.">Soluble Receptor for Advanced Glycation End-Products Predicts Impaired Alveolar Fluid Clearance in Acute Respiratory Distress Syndrome.</a> American Journal of Respiratory and Critical Care Medicine. 192 (2), 191-199 (2015).</li><li>Jabaudon, M., Blondonnet, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Soluble+Forms+and+Ligands+of+the+Receptor+for+Advanced+Glycation+End-Products+in+Patients+with+Acute+Respiratory+Distress+Syndrome:+An+Observational+Prospective+Study.">Soluble Forms and Ligands of the Receptor for Advanced Glycation End-Products in Patients with Acute Respiratory Distress Syndrome: An Observational Prospective Study.</a> PloS One. 10 (8), e0135857 (2015).</li><li>Kuehn, A., Kletting, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+alveolar+epithelial+cells+expressing+tight+junctions+to+model+the+air-blood+barrier.">Human alveolar epithelial cells expressing tight junctions to model the air-blood barrier.</a> ALTEX. 33 (3), 251-260 (2016).</li><li>Yue, T., Roth Z'graggen, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postconditioning+with+a+volatile+anaesthetic+in+alveolar+epithelial+cells+in+vitro.">Postconditioning with a volatile anaesthetic in alveolar epithelial cells in vitro.</a> The European Respiratory Journal: Official Journal of the European Society for Clinical Respiratory Physiology. 31 (1), 118-125 (2008).</li><li>Suter, D., Spahn, D. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+immunomodulatory+effect+of+sevoflurane+in+endotoxin-injured+alveolar+epithelial+cells.">The immunomodulatory effect of sevoflurane in endotoxin-injured alveolar epithelial cells.</a> Anesthesia and Analgesia. (3), 638-645 (2007).</li><li>Schl&#228;pfer, M., Leutert, A. C., Voigtsberger, S., Lachmann, R. A., Booy, C., Beck-Schimmer, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sevoflurane+reduces+severity+of+acute+lung+injury+possibly+by+impairing+formation+of+alveolar+oedema.">Sevoflurane reduces severity of acute lung injury possibly by impairing formation of alveolar oedema.</a> Clinical and Experimental Immunology. (1), 125-134 (2012).</li><li>Nickalls, R. W. D., Mapleson, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Age-related+iso-MAC+charts+for+isoflurane,+sevoflurane+and+desflurane+in+man.">Age-related iso-MAC charts for isoflurane, sevoflurane and desflurane in man.</a> British Journal of Anaesthesia. 91 (2), 170-174 (2003).</li><li>Bourdeaux, D., Sautou-Miranda, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simple+assay+of+plasma+sevoflurane+and+its+metabolite+hexafluoroisopropanol+by+headspace+GC-MS.">Simple assay of plasma sevoflurane and its metabolite hexafluoroisopropanol by headspace GC-MS.</a> Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 878 (1), 45-50 (2010).</li><li>Eger, E. I., Saidman, L. J., Brandstater, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimum+alveolar+anesthetic+concentration.">Minimum alveolar anesthetic concentration.</a> Anesthesiology. 26 (6), 756-763 (1965).</li><li>Perbet, S., Fernandez-Canal, C., Pereira, B., Cardot, J. M., Bazin, J. E., Constantin, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+Richmond+Agitation+Sedation+Scale+According+To+Alveolar+Concentration+of+Sevoflurane+During+a+Sedation+With+Sevoflurane+in+Icu+Patients.">Evaluation of Richmond Agitation Sedation Scale According To Alveolar Concentration of Sevoflurane During a Sedation With Sevoflurane in Icu Patients.</a> Intensive Care Medicine Experimental. 3 (Suppl 1), (2015).</li><li>Goolaerts, A., Pellan-Randrianarison, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conditioned+media+from+mesenchymal+stromal+cells+restore+sodium+transport+and+preserve+epithelial+permeability+in+an+in+vitro+model+of+acute+alveolar+injury.">Conditioned media from mesenchymal stromal cells restore sodium transport and preserve epithelial permeability in an in vitro model of acute alveolar injury.</a> American Journal of Physiology. Lung Cellular and Molecular Physiology. 306 (11), L975-L985 (2014).</li></ol>

Our protocol describes an easy method to expose cells to a precise fraction of a halogenated anesthetic agent, such as sevoflurane or isoflurane. Furthermore, we report here&#8212;for the first time&#8212;a rigorous correlation between both the gas fraction and the concentration of sevoflurane and isoflurane inside the culture medium itself. This fundamental step now allows us to safely use our air-tight chamber to study the effects of these halogenated agents in a cultured monolayer of human alveolar epithelial cells.</...

Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by diffuse alveolar injury, lung edema, and hypoxemic respiratory failure. Although ARDS represents more than 10% of intensive care unit (ICU) admissions and nearly 25% of ICU patients requiring mechanical ventilation, it is still an under-recognized challenge for clinicians, with a hospital mortality rate of 35-45%1. Despite intense research, the identification of an effective ARDS pharmacologic therapy or prevention has failed to date. Two major features contribute to mortality in ARDS: impaired alveolar fluid clearance (AFC) (i.e., the altered resorption of alveolar edema fluid from distal lung airspaces) and severe inflammation2. Since ARDS mortality remains high, current initiatives should also include primary prevention; however, a key challenge is to identify at-risk patients in whom ARDS is likely to develop and who would benefit if ARDS were prevented.
Volatile halogenated anesthetics, such as sevoflurane and isoflurane, are widely used to provide general anesthesia in the operating room. Worldwide, more than 230 million patients undergoing major surgery each year require general anesthesia and mechanical ventilation3, and postoperative pulmonary complications adversely affect clinical outcomes and healthcare utilization4. The use of sevoflurane instead of propofol was associated with improved lung inflammation in patients undergoing thoracic surgery and significant decreases in adverse events, such as ARDS and postoperative pulmonary complications5. Similarly, pretreatment with isoflurane had protective effects on respiratory mechanics, oxygenation, and hemodynamics in experimental animal models of ARDS6,7. Although further studies are warranted to address the impact of inhaled agents on outcomes in noncardiac surgery, a similar decrease in pulmonary complications has been recently observed in a meta-analysis, demonstrating that inhaled anesthetic agents&#8212;as opposed to intravenous anesthesia&#8212;are significantly associated with a reduction in mortality for cardiac surgery8.
Specific prospective data about the use of volatile agents for the sedation of ICU patients to prevent or treat lung damage is lacking. However, several trials now support the efficacy and safety of inhaled sevoflurane for the sedation of ICU patients, and preclinical studies have shown that inhaled sevoflurane and isoflurane7,9 improve gas exchange, reduce alveolar edema, and attenuate inflammation in experimental models of ARDS. Additionally, sevoflurane mitigates type II epithelial cell damage10, whereas isoflurane maintains the integrity of the alveolar-capillary barrier through modulation of tight junction protein11. However, further studies are needed to verify to what extent the experimental evidence of organ protection from inhaled sevoflurane and isoflurane could be translated to humans. A first single-center randomized controlled-trial (RCT) from our group found that early use of inhaled sevoflurane in patients with ARDS was associated with improved oxygenation, reduced levels of some pro-inflammatory markers, and reduced lung epithelial damage, as assessed by the levels of the soluble form of the receptor for advanced glycation end-products (sRAGE) in plasma and alveolar fluid12.
Taken together, the beneficial effects of sevoflurane and isoflurane on lung injury could point to multiple biological pathways or functional processes that are dependent on the RAGE pathway, namely alveolar fluid clearance (AFC), epithelial injury, translocation of nuclear factor (NF)-&#954;B, and macrophage activation. In addition, sevoflurane may influence the expression of the RAGE protein itself. Since previous research by our research team and others supports pivotal roles for RAGE in alveolar inflammation and lung epithelial injury/repair during ARDS, we designed an experimental model to provide a translational understanding of the mechanisms of sevoflurane in lung injury and repair13,14,15. The in vitro effects of sevoflurane and isoflurane were investigated in a novel human alveolar epithelial primary cell line specifically designed to study the air-blood barrier of the peripheral lung, hAELVi (human Alveolar Epithelial LentiVirus immortalized), with alveolar type I-like characteristics including functional tight junctions16.
While preparing the design of our in vitro investigations (e.g., cultures of alveolar epithelial cells at the air-liquid interface with exposure to &#34;inhaled&#34; sevoflurane or isoflurane, we understood from previously published studies that fractions of sevoflurane have only been assessed in the &#34;air&#34; interface17,18,19 using standard monitors (similar to those used in a clinical setting). Halogenated agent concentrations were usually chosen according to the minimum alveolar concentration (MAC) values (e.g., in humans, for sevoflurane, 0.5, 1.1, and 2.2 vol%, representing 0.25, 0.5, and 1 MAC, respectively; for isoflurane, 0.6, 0.8, and 1.3 vol% representing 0.25, 0.5, and 1 MAC, respectively)20. Indeed, sevoflurane and isoflurane concentrations have never been investigated in the culture medium itself, thus limiting the validity of previous experimental models/instruments. Furthermore, most experiments used an anaerobic jar that was sealed after the air mix containing sevoflurane had been flushed inside. As our goal was to study alveolar epithelial cells under &#34;physiologic&#34; conditions, we believed that such an anaerobic state may not be optimal and would not be compatible with long experimental durations. Therefore, we developed our own system to culture cells at the air-liquid interface and expose them to halogenated agents (sevoflurane and isoflurane) with the aim of providing precise controlled &#34;air&#34; fractions and &#34;medium&#34; concentrations for these agents. In our opinion, this experimental step, which has not been reported to date in the literature, is mandatory prior to any further in vitro investigations of sevoflurane and isoflurane.

<table>
	<tbody>
		<tr>
			<td>Sevoflurane</td>
			<td>Baxter</td>
			<td></td>
			<td>Performing experiments using sevoflurane or isoflurane while being pregnant should be strongly discouraged</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Virbac</td>
			<td></td>
			<td>Performing experiments using sevoflurane or isoflurane while being pregnant should be strongly discouraged</td>
		</tr>
		<tr>
			<td>Human Alveolar Epithelial cells</td>
			<td>InScreenex</td>
			<td>INS-CI-1015</td>
			<td></td>
		</tr>
		<tr>
			<td>huAEC Medium (ready-to-use)</td>
			<td>InScreenex</td>
			<td>INS-ME-1013-500ml</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic machine circuit</td>
			<td>Drager</td>
			<td>Fabius</td>
			<td></td>
		</tr>
		<tr>
			<td>Gas analyzer</td>
			<td>Drageer</td>
			<td>Vamos Plus</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthetic gas filter</td>
			<td>SedanaMedical</td>
			<td>FlurAbsord</td>
			<td></td>
		</tr>
		<tr>
			<td>Heated Humifier</td>
			<td>Fisher&#38;Paykel</td>
			<td>MR850</td>
			<td></td>
		</tr>
		<tr>
			<td>Chamber</td>
			<td>Curver</td>
			<td>00012-416-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Gas chromatography coupled with mass detection</td>
			<td>Thermo Fisher Scientific, San Jose, CA, USA</td>
			<td>Trace 1310 with TSQ 8000evo</td>
			<td></td>
		</tr>
		<tr>
			<td>Fused-silica column (30 m x 1.4 &#181;m, 0.25 mm ID)</td>
			<td>Restek, Lisses, France</td>
			<td>Rxi-624Sil MS</td>
			<td></td>
		</tr>
	</tbody>
</table>

in vitro method to control concentrations of halogenated gases in cultured alveolar epithelial cells

Acute respiratory distress syndrome (ARDS) is a syndrome of diffuse alveolar injury with impaired alveolar fluid clearance and severe inflammation. The use of halogenated agents, such as sevoflurane or isoflurane, for the sedation of intensive care unit (ICU) patients can improve gas exchange, reduce alveolar edema, and attenuate inflammation during ARDS. However, data on the use of inhaled agents for continuous sedation in the ICU to treat or prevent lung damage is lacking. To study the effects of halogenated agents on alveolar epithelial cells under "physiologic" conditions, we describe an easy system to culture cells at the air-liquid interface and expose them to halogenated agents to provide precise controlled "air" fractions and "medium" concentrations for these agents. We developed a sealed air-tight chamber in which plates with human alveolar epithelial immortalized cells could be exposed to a precise, controlled fraction of sevoflurane or isoflurane using a continuous gas flow provided by an anesthetic machine circuit. Cells were exposed to 4% of sevoflurane and 1% of isoflurane for 24 hours. Gas mass spectrometry was performed to determine the concentration of halogenated agents dissolved in the medium. After the first hour, the concentrations of sevoflurane and isoflurane in the medium were 251 mg/L and 25 mg/L, respectively. The curves representing the concentrations of both sevoflurane and isoflurane dissolved in the medium showed similar courses over time, with a plateau reached at one hour after exposure. 
This protocol was specifically designed to reach precise and controlled concentrations of sevoflurane or isoflurane in vitro to improve our understanding of mechanisms involved in epithelial lung injury during ARDS and to test novel therapies for the syndrome.

The concentrations of the sevoflurane and isoflurane, which dissolved in the medium over time, are reported in Table 1 and Table 2, respectively.
The courses of the sevoflurane and isoflurane concentrations in the medium were similar over time. Immediately after the required concentration of halogenated agent was set, concentrations rose over the first hour. A plateau was then reached, which per...

Watch this Scientific Journal Video about In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells at JoVE.com

In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells

We describe an easy protocol specifically designed to reach precise and controlled concentrations of sevoflurane or isoflurane in vitro in order to improve our understanding of mechanisms involved in the epithelial lung injury and to test novel therapies for acute respiratory distress syndrome.

In Vitro Method to Control Concentrations of Halogenated Gases in Cultured Alveolar Epithelial Cells

Acute respiratory distress syndrome (ARDS) is a syndrome of diffuse alveolar injury with impaired alveolar fluid clearance and severe inflammation. The ...

This method can help answer key question in the research field of lung injury and repair such as testing halogenated adjunct as potential novel therapies for acute respiratory distress syndrome. The main advantage of this technique is that it relies on a very simple method to culture the cells and to expose them to halogenated agents in order to reach precise and controlled concentrations. To construct the airtight chamber, use a hermetic polypropylene box with a capacity of 6.5 liters.Drill a 2.5 centimeter diameter hole on the bottom side of the lateral wall of the box. Then insert a corrugated tube with a green mark which will serve as the gas air mixture input pipe. And seal it with silicone.Next, drill a second hole with a 2.5 centimeter diameter on the top side of the opposite lateral wall. Insert another corrugated tube with a red mark and connect it with a charcoal filter which will serve as the gas air mixture output pipe. Then seal it with silicone.Subsequently drill a tight hole with a four millimeter diameter at the center of the wall. Insert the short infusion tubing that is connected at a manifold with a rotating male lure lock. Plug it in to a gas analyzer and seal it with silicone.Then place a digital thermometer inside the airtight chamber. Under a laboratory extractor hood, customize an anesthetic machine circuit to switch the nitrous oxide gas line by carbon dioxide. Insert a heated humidifier into the pipe between the anesthetic machine and the airtight chamber to warm the gas flow mixture to approximately 37 degrees Celsius.Plug the airtight chamber with the green marked corrugated tube into the customized anesthetic machine circuit. Next, place the airtight chamber on a hot plate set to 37 degrees Celsius. Place a six well plate containing human alveolar epithelial cells into the airtight chamber and seal the lid.Regulate the gas flow rate to quickly obtain 5%of CO2. Then open the halogenated agent evaporator and adjust the desired percentage. Once the target values are achieved, reduce the fresh gas flow rate to one liter per minute.The airtight chamber can be maintained with this gas flow rate as long as necessary for the experiment. The courses of the sevoflurane and isoflurane concentrations in the medium were similar over time. Immediately after the required concentration of halogenated agent was set, concentrations rose over the first hour.A plateau was then reached which persisted until the administration of the halogenated agent was stopped. After administration interruption, concentrations decreased within one hour. Shown here are the fractions of halogenated agent over time in the airtight chamber measured by the gas analyzer.This procedure is relatively inexpensive and very easy to adopt even when researchers have never manipulated an airtight chamber before. Following this procedure, other methods like protein and RNA quantification, immunofluorescence, measurement of protein permeability and free transport can be performed in order to answer questions on the specific effects of the halogenated agents during epithelial lung injury and its resolution. After its development, this technique may pave the way for research in the field of acute respiratory distress syndrome to further study the mechanism involved in epithelial lung injury during ARDS and to test novel therapies.

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A Simple Method of Mouse Lung Intubation

A simple procedure to intubate mice for pulmonary function measurements would have several advantages in longitudinal studies with limited numbers or expensive animal. One of the reasons that this is not done more routinely is that it is relatively difficult, despite there being several published studies that describe ways to achieve it. In this paper we demonstrate a procedure that eliminates one of the major hurdles associated with this intubation, that of visualizing the trachea during the entire time of intubation. The approach uses a 0.5 mm fiberoptic light source that serves as an introducer to direct the intubation cannula into the mouse trachea. We show that it is possible to use this procedure to measure lung mechanics in individual mice over a time course of at least several weeks. The technique can be set up with relatively little expense and expertise, and it can be routinely accomplished with relatively little training. This should make it possible for any laboratory to routinely carry out this intubation, thereby allowing longitudinal studies in individual mice, thereby minimizing the number of mice needed and increasing the statistical power by using each mouse as its own control.

This paper describes a striaghforward and efficient method of intubating mice for pulmonary function measurements or pulmonary instillation, that allows the mice to recover and be studied at later times. The procedure involves an inexpensive fiberoptic light source that directly illuminates the trachea.

A  simple procedure to intubate mice for pulmonary function measurements would  have several advantages in longitudinal studies with limited numbers or  ...

Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro

In recent years, there has been the difficulty in finding more effective therapies against cancer with less systemic side effects. Therefore Photodynamic Therapy is a novel approach for a more tumor selective treatment.
Photodynamic Therapy (PDT) that makes use of a nontoxic photosensitizer (PS), which, upon activation with light of a specific wavelength in the presence of oxygen, generates oxygen radicals that elicit a cytotoxic response1. Despite its approval almost twenty years ago by the FDA, PDT is nowadays only used to treat a limited number of cancer types (skin, bladder) and nononcological diseases (psoriasis, actinic keratosis)2.
The major advantage of the use of PDT is the ability to perform a local treatment, which prevents systemic side effects. Moreover, it allows the treatment of tumors at delicate sites (e.g. around nerves or blood vessels). Here, an intraoperative application of PDT is considered in osteosarcoma (OS), a tumor of the bone, to target primary tumor satellites left behind in tumor surrounding tissue after surgical tumor resection. The treatment aims at decreasing the number of recurrences and at reducing the risk for (postoperative) metastasis.
In the present study, we present in vitro PDT procedures to establish the optimal PDT settings for effective treatment of widely used OS cell lines that are used to reproduce the human disease in well established intratibial OS mouse models. The uptake of the PS mTHPC was examined with a spectrophotometer and phototoxicity was provoked with laser light excitation of mTHPC at 652 nm to induce cell death assessed with a WST-1 assay and by the counting of surviving cells. The established techniques enable us to define the optimal PDT settings for future studies in animal models. They are an easy and quick tool for the evaluation of the efficacy of PDT in vitro before an application in vivo.

Cytotoxic Efficacy of Photodynamic Therapy in Osteosarcoma Cells In Vitro

The protocol reported here allows the evaluation of the efficacy of photodynamic therapy (PDT) in cell lines and the optimization of the PDT settings before applying the therapy in animal models.

In recent years, there has been the difficulty in finding more effective therapies against cancer with less systemic side effects. Therefore Photodynamic ...

In vitro Method to Observe E-selectin-mediated Interactions Between Prostate Circulating Tumor Cells Derived From Patients and Human Endothelial Cells

Metastasis is a process in which tumor cells shed from the primary tumor intravasate blood vascular and lymphatic system, thereby, gaining access to extravasate and form a secondary niche.&#160;The extravasation of tumor cells from the blood vascular system can be studied using endothelial cells (ECs) and tumor cells obtained from different cell lines.&#160;Initial studies were conducted using static conditions but it has been well documented that ECs behave differently under physiological flow conditions.&#160;Therefore, different flow chamber assemblies are currently being used to studying cancer cell interactions with ECs.&#160;Current flow chamber assemblies offer reproducible results using either different cell lines or fluid at different shear stress conditions.&#160;However, to observe and study interactions with rare cells such as circulating tumor cells (CTCs), certain changes are required to be made to the conventional flow chamber assembly.&#160;CTCs are a rare cell population among millions of blood cells. Consequently, it is difficult to obtain a pure population of CTCs.&#160;Contamination of CTCs with different types of cells normally found in the circulation is inevitable using present enrichment or depletion techniques.&#160;In the present report, we describe a unique method to fluorescently label circulating prostate cancer cells and study their interactions with ECs in a self-assembled flow chamber system.&#160;This technique can be further applied to observe interactions between prostate CTCs and any protein of interest.

In vitro Method to Observe E-selectin-mediated Interactions Between Prostate Circulating Tumor Cells Derived From Patients and Human Endothelial Cells

Our report describes a unique method to visualize and analyze CTC/EC interactions in prostate cancer under physiological flow conditions.

Metastasis is a process in which tumor cells shed from the primary tumor intravasate blood vascular and lymphatic system, thereby, gaining access to ...

Studying Pancreatic Cancer Stem Cell Characteristics for Developing New Treatment Strategies

Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor initiation, metastasis and resistance to radio- and chemotherapy. Here we describe a specific methodology for culturing primary human pancreatic CSCs as tumor spheres in anchorage-independent conditions. Cells are grown in serum-free, non-adherent conditions in order to enrich for CSCs while their more differentiated progenies do not survive and proliferate during the initial phase following seeding of single cells. This assay can be used to estimate the percentage of CSCs present in a population of tumor cells. Both size (which can range from 35 to 250 micrometers) and number of tumor spheres formed represents CSC activity harbored in either bulk populations of cultured cancer cells or freshly harvested and digested tumors 1,2. Using this assay, we recently found that metformin selectively ablates pancreatic CSCs; a finding that was subsequently further corroborated by demonstrating diminished expression of pluripotency-associated genes/surface markers and reduced in vivo tumorigenicity of metformin-treated cells. As the final step for preclinical development we treated mice bearing established tumors with metformin and found significantly prolonged survival. Clinical studies testing the use of metformin in patients with PDAC are currently underway (e.g., NCT01210911, NCT01167738, and NCT01488552). Mechanistically, we found that metformin induces a fatal energy crisis in CSCs by enhancing reactive oxygen species (ROS) production and reducing mitochondrial transmembrane potential. In contrast, non-CSCs were not eliminated by metformin treatment, but rather underwent reversible cell cycle arrest. Therefore, our study serves as a successful example for the potential of in vitro sphere formation as a screening tool to identify compounds that potentially target CSCs, but this technique will require further in vitro and in vivo validation to eliminate false discoveries.

Pancreatic cancer stem cells (CSCs) can be expanded in vitro using the anchorage-independent sphere culture technique, which represents a powerful tool to study CSC biology and can serve as the first step to develop novel CSC-targeting therapies. Here the methodology for expanding, analyzing and targeting of pancreatic CSCs is provided.

Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor ...

Studying the Role of Alveolar Macrophages in Breast Cancer Metastasis

This paper describes the application of the syngeneic model of breast cancer (4T1) to the studies on a role of pulmonary alveolar macrophages in cancer metastasis. The 4T1 cells expressing GFP in combination with imaging and confocal microscopy are used to monitor tumor growth, track metastasizing tumor cells, and quantify the metastatic burden. These approaches are supplemented by digital histopathology that allows the automated and unbiased quantification of metastases. In this method the routinely prepared histological lung sections, which are stained with hematoxylin and eosin, are scanned and converted to the digital slides that are then analyzed by the self-trained pattern recognition software. In addition, we describe the flow cytometry approaches with the use of multiple cell surface markers to identify alveolar macrophages in the lungs. To determine impact of alveolar macrophages on metastases and antitumor immunity these cells are depleted with the clodronate-containing liposomes administrated intranasally to tumor-bearing mice. This approach leads to the specific and efficient depletion of this cell population as confirmed by flow cytometry. Tumor volumes and lung metastases are evaluated in mice depleted of alveolar macrophages, to determine the role of these cells in the metastatic progression of breast cancer.

Here we describe the model and approach to study functions of pulmonary alveolar macrophages in cancer metastasis. To demonstrate the role of these cells in metastasis, the syngeneic (4T1) model of breast cancer in conjunction with the depletion of alveolar macrophage with clodronate liposomes was used.

This paper describes the application of the syngeneic model of breast cancer (4T1) to the studies on a role of pulmonary alveolar macrophages in cancer ...

Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients

Recently-developed cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drugs correct surface expression and/or function of the mutant CFTR channel in subjects with cystic fibrosis (CF). Identification of subjects that may benefit from these drugs is challenging because of the extensive heterogeneity of CFTR mutations, as well as other unknown factors that contribute to individual drug efficacy. Here, we describe a simple and relatively rapid assay for measuring individual CFTR function and response to CFTR modulators in vitro. Three dimensional (3D) epithelial organoids are grown from rectal biopsies in standard organoid medium. Once established, the organoids can be bio-banked for future analysis. For the assay, 30-80 organoids are seeded in 96-well plates in basement membrane matrix and are then exposed to drugs. One day later, the organoids are stained with calcein green, and forskolin-induced swelling is monitored by confocal live cell microscopy at 37 &#176;C. Forskolin-induced swelling is fully CFTR-dependent and is sufficiently sensitive and precise to allow for discrimination between the drug responses of individuals with different and even identical CFTR mutations. In vitro swell responses correlate with the clinical response to therapy. This assay provides a cost-effective approach for the identification of drug-responsive individuals, independent of their CFTR mutations. It may also be instrumental in the development of future CFTR modulators.

Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients

This protocol describes an assay for measuring CFTR function and CFTR modulator responses in cultured tissue from subjects with cystic fibrosis (CF). Biopsy-derived intestinal organoids swell in a cAMP-driven fashion, a response that is defective (or strongly reduced) in CF organoids and can be restored by exposure to CFTR modulators.

Recently-developed cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drugs correct surface expression and/or function of the mutant ...

A Method for Quantifying Upper Limb Performance in Daily Life Using Accelerometers

A key reason for referral to rehabilitation services after stroke and other neurological conditions is to improve one's ability to function in daily life. It has become important to measure a person's activities in daily life, and not just measure their capacity for activity in the structured environment of a clinic or laboratory. A wearable sensor that is now enabling measurement of daily movement is the accelerometer. Accelerometers are commercially-available devices resembling large wrist watches that can be worn throughout the day. Data from accelerometers can quantify how the limbs are engaged to perform activities in peoples' homes and communities. This report describes a methodology to collect accelerometry data and turn it into clinically-relevant information. First, data are collected by having the participant wear two accelerometers (one on each wrist) for 24 h or longer. The accelerometry data are then downloaded and processed to produce four different variables that describe key aspects of upper limb activity in daily life: hours of use, use ratio, magnitude ratio, and the bilateral magnitude. Density plots can be constructed that visually represent the data from the 24 h wearing period. The variables and their resultant density plots are highly consistent in neurologically-intact, community-dwelling adults. This striking consistency makes them a useful tool for determining if upper limb daily performance is different from normal. This methodology is appropriate for research studies investigating upper limb dysfunction and interventions designed to improve upper limb performance in daily life in people with stroke and other patient populations. Because of its relative simplicity, it may not be long before it is also incorporated in clinical neurorehabilitation practice.

This protocol describes a method to quantify upper limb performance in daily life using wrist-worn accelerometers.

A key reason for referral to rehabilitation services after stroke and other neurological conditions is to improve one's ability to function in daily life. ...

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During In Vitro Wound Healing

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated experimental procedures, while potentially lacking in precision. In vitro culture of epithelial cell lines provides a suitable platform for researching the cell migratory behavior in wound healing and the impact of treatments on these cells. The physiology of epithelial cells is often studied in non-confluent conditions; however, this approach may not resemble natural wound healing conditions. Disrupting the epithelium integrity by mechanical means generates a realistic model, but may impede the application of molecular techniques. Consequently, microscopy based techniques are optimal for studying epithelial cell migration in vitro. Here we detail two specific methods, the artificial wound scratch assay and the artificial migration front assay, that can obtain quantitative and qualitative data, respectively, on the migratory performance of epithelial cells.

Microscopy Based Methods for the Assessment of Epithelial Cell Migration During  In Vitro Wound Healing

This manuscript describes how incision-like lesions made on cultured epithelial cell monolayers conveniently model wound healing in vitro, allowing for imaging by confocal or laser scanning microscopy, and which can provide high-quality quantitative and qualitative data for studying both cell behavior and the mechanisms involved in migration.

Cell migration is a mandatory aspect for wound healing. Creating artificial wounds on research animal models often results in costly and complicated ...

Corneal Epithelial Abrasion with Ocular Burr As a Model for Cornea Wound Healing

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to injury. In fact, the most common type of eye injury found in clinic is a corneal abrasion. Here, we utilize an ocular burr to induce an abrasion resulting in removal of the corneal epithelium in vivo on anesthetized mice. This method allows for targeted and reproducible epithelial disruption, leaving other areas intact. In addition, we describe the visualization of the abraded epithelium with fluorescein staining and provide concrete advice on how to visualize the abraded cornea. Then, we follow the timeline of wound healing 0, 18, and 72 h after abrasion, until the wound is re-epithelialized. The epithelial abrasion model of corneal injury is ideal for studies on epithelial cell proliferation, migration and re-epithelialization of the corneal layers. However, this method is not optimal to study stromal activation during wound healing, because the ocular burr does not penetrate to the stromal cell layers. This method is also suitable for clinical applications, for example, pre-clinical test of drug effectiveness.

This protocol describes a method to inflict an abrasion to the ocular surface of the mouse, and to follow the wound healing process thereafter. The protocol takes advantage of an ocular burr to partially remove the surface epithelium of the eye in anaesthetized mice.

The murine cornea provides an excellent model to study wound healing. The cornea is the outermost layer of the eye, and thus is the first defense to ...

Electroporation-Based Genetic Modification of Primary Human Pigment Epithelial Cells Using the Sleeping Beauty Transposon System

Our increasingly aging society leads to a growing incidence of neurodegenerative diseases. So far, the pathological mechanisms are inadequately understood, thus impeding the establishment of defined treatments. Cell-based additive gene therapies for the increased expression of a protective factor are considered as a promising option to medicate neurodegenerative diseases, such as age-related macular degeneration (AMD). We have developed a method for the stable expression of the gene encoding pigment epithelium-derived factor (PEDF), which is characterized as a neuroprotective and anti-angiogenic protein in the nervous system, into the genome of primary human pigment epithelial (PE) cells using the Sleeping Beauty (SB) transposon system. Primary PE cells were isolated from human donor eyes and maintained in culture. After reaching confluence, 1 x 104 cells were suspended in 11 &#181;L of resuspension buffer and combined with 2 &#181;L of a purified solution containing 30 ng of hyperactive SB (SB100X) transposase plasmid and 470 ng of PEDF transposon plasmid. Genetic modification was carried out with a capillary electroporation system using the following parameters: two pulses with a voltage of 1,100 V and a width of 20 ms. Transfected cells were transferred into culture plates containing medium supplemented with fetal bovine serum; antibiotics and antimycotics were added with the first medium exchange. Successful transfection was demonstrated in independently performed experiments. Quantitative polymerase chain reaction (qPCR) showed the increased expression of the PEDF transgene. PEDF secretion was significantly elevated and remained stable, as evaluated by immunoblotting, and quantified by enzyme-linked immunosorbent assay (ELISA). SB100X-mediated transfer allowed for a stable PEDF gene integration into the genome of PE cells and ensured the continuous secretion of PEDF, which is critical for the development of a cell-based gene addition therapy to treat AMD or other retinal degenerative diseases. Moreover, analysis of the integration profile of the PEDF transposon into human PE cells indicated an almost random genomic distribution.

We have developed a protocol to transfect primary human pigment epithelial cells by electroporation with the gene encoding pigment epithelium-derived factor (PEDF) using the Sleeping Beauty (SB) transposon system. Successful transfection was demonstrated by quantitative polymerase chain reaction (qPCR), immunoblotting, and enzyme-linked immunosorbent assay (ELISA).