This study was partly supported by a grant from Meridigen Biotech Co., Ltd. Taipei, Taiwan (A-109-008).

This procedure was approved by the Animal Care and Use Committee at Taipei Medical University.
NOTE: Human MSCs stably transfected with green fluorescent protein (GFP) and firefly luciferase genes (Fluc) were obtained from a commercial company (Table of Materials).
1. Characterization of human MSCs with firefly luciferase and green fluorescent protein
<ol>
	<li>Maintain human MSCs transfected with GFP and Fluc in complete media (minimum essential medium eagle-alpha modification [&#945;MEM], supplemented with 10&#8722;15% fetal bovine serum [FBS], 2 mM L-glutamine, 1 ng/mL basic FGF, and PSF) at 37 &#176;C with saturated humidity and 5% CO2. Passage cells at ~70&#8722;90% confluence.</li>
	<li>Observe MSCs under a fluorescence phase contrast microscope (Figure 1A) and analyze the expression levels of Fluc and GFP14.</li>
	<li>Characterize the MSCs by analyzing the expression of CD markers including CD44, CD73, CD90, CD105 using flow cytometry (Figure 1B). Induce trilineage differentiation of stem cells to adipocytes, chondrocytes, and osteocytes, and confirm trilineage differentiation (Figure 1C) by von Kossa, oil red O, and Alcian blue staining following a commercial protocol15,16.</li>
</ol>
2. Anesthetization of rat pups
<ol>
	<li>Allow time-dated pregnant Sprague&#8211;Dawley rats to deliver vaginally at term.</li>
	<li>Remove the rat pups from the cage on postnatal day 5.</li>
	<li>Anesthetize the rat pups using gas anesthesia (i.e., 2% isoflurane) in an anesthesia chamber.</li>
	<li>Confirm adequate anesthesia by checking breathing and reflexes. 
	NOTE: Breathing should become shallow and reflexes should diminish. Rat pups remain unconscious for at least ~10 min with this isoflurane concentration.</li>
</ol>
3. Intratracheal instillation
<ol>
	<li>Once anesthetized, restrain the rat pups on an intubation stand angled at ~60&#176; and hold pups in place with laboratory labeling tape on all four limbs.</li>
	<li>Apply tape below the nose to fix the head and pinpoint the neck for puncture tracheotomy.</li>
	<li>Disinfect the incision area (i.e., neck) with a 75% alcohol prep pad.</li>
	<li>Make a 0.3 cm vertical midline neck incision above the trachea with microscissors to avoid damaging the carotid arteries.</li>
	<li>Dissect the fat and muscle layers away to locate the trachea with curved tip tapered tweezers without a hook.</li>
	<li>Hold the trachea with the curved tip tapered tweezers.</li>
	<li>Hold a 100 &#956;L syringe upright and slowly inject 30 &#956;L of normal saline (i.e., control) or 30 &#956;L of Fluc-GFP labeled MSCs (1 x 105 cells) into the trachea through a 30 G needle syringe during inspiratory phase.</li>
	<li>Close the incision with one 6-0 silk stitch, tie the knot as small as possible, and cut the ends as short as possible.</li>
	<li>Place the rats under infrared light or on a heating pad to keep warm and allow them to recover from anesthesia.</li>
	<li>Confirm the rats are warm, pink, and capable of spontaneous movement before returning the rats to the cage.</li>
</ol>
4. Monitoring the pulmonary distribution of MSCs
<ol>
	<li>To track the transplanted human MSCs, intraperitoneally inject the rats with luciferin potassium salt in phosphate buffered saline (PBS) at a dose of 125 mg/kg of body weight 15 min after MSC injection.</li>
	<li>Anesthetize the rats using 2% isoflurane through nose cones.</li>
	<li>Acquire sequential images at 5&#8211;15 s intervals 10 min after luciferin administration with medium binning, 1 f/stop, and a 26 cm field of view using a small-animal imaging system (Table of Materials).</li>
	<li>Quantify the luminescence activity from the lungs based on the automatic regions of interest using imaging software (Table of Materials)17.</li>
</ol>

<ol>
	<li>Ramanathan, R., Bhatia, J. J., Sekar, K., Ernst, F. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mortality+in+preterm+infants+with+respiratory+distress+syndrome+treated+with+poractant+alfa,+calfactant+or+beractant:+a+retrospective+study.">Mortality in preterm infants with respiratory distress syndrome treated with poractant alfa, calfactant or beractant: a retrospective study.</a> Journal of Perinatology. 33, 119-125 (2013).</li><li>Gien, J., Kinsella, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pathogenesis+and+treatment+of+bronchopulmonary+dysplasia.">Pathogenesis and treatment of bronchopulmonary dysplasia.</a> Current Opinion in Pediatrics. 23, 305-313 (2011).</li><li>Pasha, A. B., Chen, X. Q., Zhou, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bronchopulmonary+dysplasia:+Pathogenesis+and+treatment.">Bronchopulmonary dysplasia: Pathogenesis and treatment.</a> Experimental and Therapeutic. 16, 4315-4321 (2018).</li><li>Committee on Fetus and Newborn. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postnatal+corticosteroids+to+treat+or+prevent+chronic+lung+disease+in+preterm+infants.">Postnatal corticosteroids to treat or prevent chronic lung disease in preterm infants.</a> Pediatrics. 109, 330-338 (2002).</li><li>Watterberg, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=American+Academy+of+Pediatrics;+Committee+on+Fetus+and+Newborn.+Policy+statement-postnatal+corticosteroids+to+prevent+or+treat+bronchopulmonary+dysplasia.">American Academy of Pediatrics; Committee on Fetus and Newborn. Policy statement-postnatal corticosteroids to prevent or treat bronchopulmonary dysplasia.</a> Pediatrics. 126, 800-808 (2010).</li><li>Prockop, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Marrow+stromal+cells+as+stem+cells+for+nonhematopoietic+tissues.">Marrow stromal cells as stem cells for nonhematopoietic tissues.</a> Science. 276, 71-74 (1997).</li><li>Nemeth, K., 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=Bone+marrow+stromal+cells+attenuate+sepsis+via+prostaglandin+E(2)-+dependent+reprogramming+of+host+macrophages+to+increase+their+interleukin-10+production.">Bone marrow stromal cells attenuate sepsis via prostaglandin E(2)- dependent reprogramming of host macrophages to increase their interleukin-10 production.</a> Nature Medicine. 15 (2), 42-49 (2009).</li><li>Chou, H. C., Li, Y. T., Chen, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+mesenchymal+stem+cells+attenuate+experimental+bronchopulmonary+dysplasia+induced+by+perinatal+inflammation+and+hyperoxia.">Human mesenchymal stem cells attenuate experimental bronchopulmonary dysplasia induced by perinatal inflammation and hyperoxia.</a> American Journal of Translational Research. 8, 342-353 (2016).</li><li>Chen, C. M., Chou, H. C., Lin, W., Tseng, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surfactant+effects+on+the+viability+and+function+of+human+mesenchymal+stem+cells:+in+vitro+and+in+vivo+assessment.">Surfactant effects on the viability and function of human mesenchymal stem cells: in vitro and in vivo assessment.</a> Stem Cell Research &amp; Therapy. 8, 180 (2017).</li><li>Kim, Y. 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=Intratracheal+transplantation+of+mesenchymal+stem+cells+simultaneously+attenuates+both+lung+and+brain+injuries+in+hyperoxic+newborn+rats.">Intratracheal transplantation of mesenchymal stem cells simultaneously attenuates both lung and brain injuries in hyperoxic newborn rats.</a> Pediatric Research. 80, 415-424 (2016).</li><li>Fleurence, 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=Comparative+efficacy+of+intratracheal+adeno-associated+virus+administration+to+newborn+rats.">Comparative efficacy of intratracheal adeno-associated virus administration to newborn rats.</a> Human Gene Therapy. 16, 1298-1306 (2005).</li><li>Waszak, 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=Effect+of+intratracheal+adenoviral+vector+administration+on+lung+development+in+newborn+rats.">Effect of intratracheal adenoviral vector administration on lung development in newborn rats.</a> Human Gene Therapy. 13, 1873-1885 (2002).</li><li>O'Reilly, M., Th&#233;baud, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+bronchopulmonary+dysplasia.+The+term+rat+models.">Animal models of bronchopulmonary dysplasia. The term rat models.</a> American Journal of Physiology-Lung Cellular and Molecular Physiology. 307, 948 (2014).</li><li>Yu, 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=GFP+labeling+and+hepatic+differentiation+potential+of+human+placenta-derived+mesenchymal+stem+cells.">GFP labeling and hepatic differentiation potential of human placenta-derived mesenchymal stem cells.</a> Cellular Physiology and Biochemistry. 35, 2299-2308 (2015).</li><li>Dominici, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minimal+criteria+for+defining+multipotent+mesenchymal+stromal+cells.+The+International+Society+for+Cellular+Therapy+position+statement.">Minimal criteria for defining multipotent mesenchymal stromal cells. The International Society for Cellular Therapy position statement.</a> Cytotherapy. 8, 315-317 (2006).</li><li>Zhang, Z. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superior+osteogenic+capacity+for+bone+tissue+engineering+of+fetal+compared+with+perinatal+and+adult+mesenchymal+stem+cells.">Superior osteogenic capacity for bone tissue engineering of fetal compared with perinatal and adult mesenchymal stem cells.</a> Stem Cells. 27, 126-137 (2009).</li><li>Huang, L. 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=Effect+of+surfactant+and+budesonide+on+pulmonary+distribution+of+fluorescent+dye+in+mice.">Effect of surfactant and budesonide on pulmonary distribution of fluorescent dye in mice.</a> Pediatric and Neonatology. 56, 19-24 (2015).</li><li>Keyaerts, M., Caveliers, V., Lahoutte, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioluminescence+imaging:+looking+beyond+the+light.">Bioluminescence imaging: looking beyond the light.</a> Trends in Molecular Medicine. 18, 164-172 (2012).</li><li>Yeh, T. 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=Intra-tracheal+administration+of+budesonide/surfactant+to+prevent+bronchopulmonary+dysplasia.">Intra-tracheal administration of budesonide/surfactant to prevent bronchopulmonary dysplasia.</a> American Journal of Respiratory and Critical Care Medicine. 193, 86-95 (2016).</li><li>Nguyen, J. Q., 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=Intratracheal+inoculation+of+Fischer+344+rats+with+Francisella+tularensis.">Intratracheal inoculation of Fischer 344 rats with Francisella tularensis.</a> Journal of Visualized Experiments. (127), e56123 (2017).</li><li>de Almeida, P. E., van Rappard, J. R., Wu, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+bioluminescence+for+tracking+cell+fate+and+function.">In vivo bioluminescence for tracking cell fate and function.</a> American Journal of Physiology-Heart and Circulatory Physiology. 301, 663-671 (2011).</li><li>Kim, J. E., Kalimuthu, S., Ahn, B. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+cell+tracking+with+bioluminescence+imaging.">In vivo cell tracking with bioluminescence imaging.</a> Nuclear Medicine and Molecular Imaging. 49, 3-10 (2011).</li></ol>

The authors have nothing to disclose.

Newborn infants with respiratory distress commonly require intratracheal surfactant and/or corticosteroid treatment19. Human phase I clinical trials have demonstrated the safety of intratracheal MSCs in preterm infants8. These studies suggest that intratracheal administration of drugs is an important option for newborn infants with respiratory distress. Animal model studies are most helpful if the model features are directly pertinent to humans. Term...

Supplemental oxygen is often required to treat newborn infants with respiratory distress1. However, hyperoxia therapy in infants has adverse long-term effects. Prolonged exposure to high concentrations of oxygen leads to inflammation and acute lung injury, which is similar to human bronchopulmonary dysplasia (BPD)2. BPD is a major complication of hyperoxia treatment that can occur in spite of early surfactant therapy, optimal ventilation procedures, and increased use of noninvasive positive pressure ventilation in premature infants. While many treatment strategies have been reported for BPD3, no known therapy can reduce this complication.
Corticosteroid use is one potential treatment to prevent BPD, because pulmonary inflammation plays a crucial role in its pathogenesis. However, systemic corticosteroid therapy is not usually recommended for preterm infants due to long-term adverse effects4,5.
Mesenchymal stromal cells (MSCs) have pluripotent characteristics and can differentiate into various cell types, including bone, cartilage, adipose tissue, muscle, and tendons6. MSCs have immunomodulatory, anti-inflammatory, and regenerative effects7, and animal studies show the therapeutic benefits of MSCs and their secreted components in hyperoxia-induced lung injury in rodents8,9. Intratracheal and intravenous MSC transplantation has been shown to protect against neonatal hyperoxic lung injury. Therefore, intratracheal administration of stem cells and combined surfactant and corticosteroid therapy might be a potential treatment strategy to treat newborns with respiratory disorders. Preclinical studies have used intratracheal administration of stem cells and adeno-associated virus in newborn rats10,11,12. However, a step-by-step presentation of the technique and in vivo tracking of the transplanted stem cells is not available. The newborn rat is appropriate for studying the effects of intratracheal administration on preterm infants with respiratory distress because the saccular stage of the rat lung at birth is equivalent to that of the human lung at 26&#8722;28 week of gestation13. An effective method for administration into the rat trachea is crucial for successful pulmonary distribution. The technique presented here allows for the study of intratracheal administration of cells and/or drugs for treatment of neonatal pulmonary diseases using rats as a model for humans.

<table>
	<tbody>
		<tr>
			<td>6-0 silk</td>
			<td>Ethicon</td>
			<td>1916G</td>
			<td></td>
		</tr>
		<tr>
			<td>Alcohol Prep Pad</td>
			<td>CSD</td>
			<td>3032</td>
			<td></td>
		</tr>
		<tr>
			<td>BD Stemflow hMSC Analysis Kit</td>
			<td>BD Biosciences</td>
			<td>562245</td>
			<td>CD markers</td>
		</tr>
		<tr>
			<td>CMV-Luciferase-EF1&#945;-copGFP BLIV 2.0 Lentivector for In Vivo Imaging</td>
			<td>SBI</td>
			<td>BLIV511PA-1</td>
			<td></td>
		</tr>
		<tr>
			<td>CryoStor10</td>
			<td>BioLife Solutions</td>
			<td>640222</td>
			<td></td>
		</tr>
		<tr>
			<td>Human MSCs</td>
			<td>Meridigen Biotech Co., Ltd. Taipei, Taiwan</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Infrared light</td>
			<td>JING SHANG</td>
			<td>JS300T</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Halocarbon</td>
			<td>26675-46-7</td>
			<td></td>
		</tr>
		<tr>
			<td>IVIS-200 small animal imaging system</td>
			<td>Caliper LifeSciences, Hopkinton, MA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Luciferin potassium salt</td>
			<td>Promega, Madison, WI</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro-scissors, straight</td>
			<td>Vannas</td>
			<td>H4240</td>
			<td></td>
		</tr>
		<tr>
			<td>Normal saline</td>
			<td>TAIWAN BIOTECH CO., LTD.</td>
			<td>113531</td>
			<td>Isotonic Sodium Chloride Solution</td>
		</tr>
		<tr>
			<td>Small Hub RN Needle, 30 gauge</td>
			<td>Hamilton Company, Reno, NV</td>
			<td>7799-06</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe (100 &#181;l)</td>
			<td>Hamilton Company, Reno, NV</td>
			<td>81065</td>
			<td></td>
		</tr>
		<tr>
			<td>Xenogen Living Image 2.5 software</td>
			<td>Caliper LifeSciences, Hopkinton, MA</td>
			<td>N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

intratracheal instillation of stem cells in term neonatal rats

Prolonged exposure to high concentrations of oxygen leads to inflammation and acute lung injury, which is similar to human bronchopulmonary dysplasia (BPD). In premature infants, BPD is a major complication despite early use of surfactant therapy, optimal ventilation strategies, and noninvasive positive pressure ventilation. Because pulmonary inflammation plays a crucial role in the pathogenesis of BPD, corticosteroid use is one potential treatment to prevent it. Nevertheless, systemic corticosteroid treatment is not usually recommended for preterm infants due to long-term adverse effects. Preclinical studies and human phase I clinical trials demonstrated that use of mesenchymal stromal cells (MSCs) in hyperoxia-induced lung injuries and in preterm infants is safe and feasible. Intratracheal and intravenous MSC transplantation has been shown to protect against neonatal hyperoxic lung injury. Therefore, intratracheal administration of stem cells and combined surfactant and glucocorticoid treatment has emerged as a new strategy to treat newborns with respiratory disorders. The developmental stage of rat lungs at birth is equivalent to that in human lungs at 26&#8722;28 week of gestation. Hence, newborn rats are appropriate for studying intratracheal administration to preterm infants with respiratory distress to evaluate its efficacy. This intratracheal instillation technique is a clinically viable option for delivery of stem cells and drugs into the lungs.

The pulmonary distribution of intratracheal instillation of stem cells in the term neonatal rats was determined by firefly luciferase (Fluc)-labeled stem cells. MSCs were labeled with Fluc and tagged with green fluorescent protein through lentiviral transduction. Figure 1A demonstrates a high level of GFP expression in human MSCs, and 93.7% of the population showed GFP positive expression detected by flow cytometry. MSCs were characterized by analyzing the expression of CD markers (i.e., CD ...

Watch this Scientific Journal Video about Intratracheal Instillation of Stem Cells in Term Neonatal Rats at JoVE.com

Intratracheal Instillation of Stem Cells in Term Neonatal Rats

Described is a protocol for performing intratracheal transplantation of mesenchymal stromal cells (MSCs) through intratracheal injection in term neonatal rats. This technique is a clinically viable option for delivery of stem cells and drugs into neonatal rat lungs to evaluate their efficacy.

Prolonged exposure to high concentrations of oxygen leads to inflammation and acute lung injury, which is similar to human bronchopulmonary dysplasia ...

intratracheal-instillation-of-stem-cells-in-term-neonatal-rats

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5.5K Views.  Taipei Medical University. Described is a protocol for performing intratracheal transplantation of mesenchymal stromal cells (MSCs) through intratracheal injection in term neonatal rats. This technique is a clinically viable option for delivery of stem cells and drugs into neonatal rat lungs to evaluate their efficacy.

Video: Intratracheal Instillation of Stem Cells in Term Neonatal Rats

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

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

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

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

Intubation-mediated Intratracheal (IMIT) Instillation: A Noninvasive, Lung-specific Delivery System

Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences between the murine and human respiratory systems, especially in their upper respiratory tracts (URT). In some models, these differences in the murine nasal cavity can have a significant impact on disease progression and presentation in the lower respiratory tract (LRT) when using intranasal instillation techniques, potentially limiting the usefulness of the mouse model to study these diseases. For these reasons, it would be advantageous to develop a technique to instill bacteria directly into the mouse lungs in order to study LRT disease in the absence of involvement of the URT. We have termed this lung specific delivery technique intubation-mediated intratracheal (IMIT) instillation. This noninvasive technique minimizes the potential for instillation into the bloodstream, which can occur during more invasive traditional surgical intratracheal infection approaches, and limits the possibility of incidental digestive tract delivery. IMIT is a two-step process in which mice are first intubated, with an intermediate step to ensure correct catheter placement into the trachea, followed by insertion of a blunt needle into the catheter to mediate direct delivery of bacteria into the lung. This approach facilitates a &#62;98% efficacy of delivery into the lungs with excellent distribution of reagent throughout the lung. Thus, IMIT represents a novel approach to study LRT disease and therapeutic delivery directly into the lung, improving upon the ability to use mice as surrogates to study human respiratory disease. Furthermore, the accuracy and reproducibility of this delivery system also makes it amenable to Good Laboratory Practice Standards (GLPS), as well as delivery of a wide range of reagents which require high efficiency delivery to the lung.

Intubation-mediated Intratracheal IMIT Instillation: A Noninvasive, Lung-specific Delivery System

Intubation-mediated intratracheal (IMIT) instillation of reagents is an excellent, noninvasive method for studying respiratory disease, as well as a method for instilling therapeutic reagents directly into the lung. It is a rapid and highly reproducible method which is suitable for preclinical testing.

Respiratory disease studies typically involve the use of murine models as surrogate systems. However, there are significant physiologic differences ...

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 ...

Long-Term Catheterization of the Intestinal Lymph Trunk and Collection of Lymph in Neonatal Pigs

Catheterization of the intestinal lymph trunk in neonatal pigs is a technique allowing for the long-term collection of large quantities of intestinal (central) efferent lymph. Importantly, the collection of central lymph from the intestine enables researchers to study both the mechanisms and lipid constitutes associated with lipid metabolism, intestinal inflammation and cancer metastasis, as well as cells involved in immune function and immunosurveillance. A ventral mid-line surgical approach permits excellent surgical exposure to the cranial abdomen and relatively easy access to the intestinal lymph trunk vessel that lies near the pancreas and the right ventral segment of the portal vein underneath the visceral aspect of the right liver lobe. The vessel is meticulously dissected and released from the surrounding fascia and then dilated with sutures allowing for insertion and subsequent securing of the catheter into the vessel. The catheter is exteriorized and approximately 1 L/24 hr of lymph is collected over a 7 day period. While this technique enables the collection of large quantities of central lymph over an extended period of time, the success depends on careful surgical dissection, tissue handling and close attention to proper surgical technique. This is particularly important with surgeries in young animals as the lymph vessels can easily tear, potentially leading to surgical and experimental failure. The video demonstrates an excellent surgical technique for the collection of intestinal lymph.

We present a surgical procedure to catheterize the intestinal lymph trunk in neonatal pigs to collect large quantities of lipid metabolism components from efferent lymph.

Catheterization of the intestinal lymph trunk in neonatal pigs is a technique allowing for the long-term collection of large quantities of intestinal ...

A Neonatal Mouse Spinal Cord Compression Injury Model

Spinal cord injury (SCI) typically causes devastating neurological deficits, particularly through damage to fibers descending from the brain to the spinal cord. A major current area of research is focused on the mechanisms of adaptive plasticity that underlie spontaneous or induced functional recovery following SCI. Spontaneous functional recovery is reported to be greater early in life, raising interesting questions about how adaptive plasticity changes as the spinal cord develops. To facilitate investigation of this dynamic, we have developed a SCI model in the neonatal mouse. The model has relevance for pediatric SCI, which is too little studied. Because neural plasticity in the adult involves some of the same mechanisms as neural plasticity in early life1, this model may potentially have some relevance also for adult SCI. Here we describe the entire procedure for generating a reproducible spinal cord compression (SCC) injury in the neonatal mouse as early as postnatal (P) day 1. SCC is achieved by performing a laminectomy at a given spinal level (here described at thoracic levels 9-11) and then using a modified Yasargil aneurysm mini-clip to rapidly compress and decompress the spinal cord. As previously described, the injured neonatal mice can be tested for behavioral deficits or sacrificed for ex vivo physiological analysis of synaptic connectivity using electrophysiological and high-throughput optical recording techniques1. Earlier and ongoing studies using behavioral and physiological assessment have demonstrated a dramatic, acute impairment of hindlimb motility followed by a complete functional recovery within 2 weeks, and the first evidence of changes in functional circuitry at the level of identified descending synaptic connections1.

This article describes a method for generating a reproducible spinal cord compression injury (SCI) in the neonatal mouse. The model provides an advantageous platform for studying mechanisms of adaptive plasticity that underlie spontaneous functional recovery.

Spinal cord injury (SCI) typically causes devastating neurological deficits, particularly through damage to fibers descending from the brain to the spinal ...

Transient Middle Cerebral Artery Occlusion Model of Neonatal Stroke in P10 Rats

A number of animal models have been used to study hypoxic-ischemic injury, traumatic injury, global hypoxia, or permanent ischemia in both the immature and mature brain. Stroke occurs commonly in the perinatal period in humans, and transient ischemia-reperfusion is the most common form of stroke in neonates. The reperfusion phase is a critical component of injury progression, which occurs over a period of days to weeks, and of the endogenous response to injury. This postnatal day 10 (p10) rat model of transient middle cerebral artery occlusion (tMCAO) creates a unilateral, non-hemorrhagic focal ischemia-reperfusion injury that can be utilized to study the mechanisms of focal injury and repair in the full-term-equivalent brain. The injury pattern that is produced by tMCAO is consistent and highly reproducible and can be confirmed with MRI or histological analyses. The severity of injury can be manipulated through changes in occlusion time and other methods that will be discussed.

Neonatal stroke is a significant cause of early brain injury requiring a translational model with consistent focal injury patterns and high reproducibility in order to enable study. This study describes the detailed surgical procedure for creating a non-hemorrhagic, unilateral focal ischemia-reperfusion injury in full-term-equivalent rodents.

A number of animal models have been used to study hypoxic-ischemic injury, traumatic injury, global hypoxia, or permanent ischemia in both the immature ...

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 ...

In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice

Enteric bacterial communities are established early in life and influence immune cell development and function. The neonatal microbiota is susceptible to numerous external influences including antibiotics use and diet, which impacts susceptibility to autoimmune and inflammatory diseases. Disorders such as Inflammatory Bowel Disease (IBD) are characterized by a massive influx of immune cells to the intestines. However, immune cells conditioned by the microbiota may additionally emigrate out of the intestines to influence immune responses at extra-intestinal sites. Thus, there is a need to identify and characterize cells that may carry microbial messages from the intestines to distal sites. Here, we describe a method to label cells in the colon of newborn mice in vivo that enables their identification at extra-intestinal sites after migration.

In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice

The protocol described here utilizes a photolabeling approach in newborn mice to specifically identify immune cells that emigrate from the colon to extra-intestinal sites. This strategy will be useful to study host-microbiome interactions in early life.

Enteric bacterial communities are established early in life and influence immune cell development and function. The neonatal microbiota is susceptible to ...

A Pleural Effusion Model in Rats by Intratracheal Instillation of Polyacrylate/Nanosilica

Pleural effusion is a prevalent clinical finding of many pulmonary diseases. Having a useful animal pleural effusion model is very important to study these pulmonary diseases. Previous pleural effusion models paid more attention to biological factors rather than nanoparticles in the environment. Here, we introduce a model to make pleural effusion in rats by intratracheal instillation of polyacrylate/nanosilica, and a method of nanoparticle isolation in the pleural effusion. By intratracheal instillation of polyacrylate/nanosilica with concentrations of 3.125, 6.25 and 12.5 mg/kg&#8729;mL, the pleural effusion in rats presented on day 3, peaked at days 7-10 in 6.25 and 12.5 mg/kg&#8729;mL groups, then slowly decreased and disappeared on day 14. When the concentration of polyacrylate/nanosilica increased, the pleural effusion is produced more and faster. This pleural fluid was detected by ultrasound examination or CT chest scanning and confirmed by dissection of rats. Silica nanoparticles were observed in the rats' pleural effusion by transmission electron microscope. These results showed that the exposure to polyacrylate/nanosilica leads to the induction of pleural effusion, which was consistent with our previous report in humans. Additionally, this model is beneficial for the further study of nanotoxicology and the pleural effusion diseases.

Here, we present a protocol to construct a pleural effusion model in rats by intratracheal instillation of polyacrylate/nanosilica.

Pleural effusion is a prevalent clinical finding of many pulmonary diseases. Having a useful animal pleural effusion model is very important to study ...

Inducing Acute Lung Injury in Mice by Direct Intratracheal Lipopolysaccharide Instillation

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. Various approaches have been described, such as the inhalation of aerosolized LPS as well as nasal or intratracheal instillation. The presented protocol describes a detailed step-by-step procedure to induce ALI in mice by direct intratracheal LPS instillation and perform FACS analysis of blood samples, bronchoalveolar lavage (BAL) fluid, and lung tissue. After intraperitoneal sedation, the trachea is exposed and LPS is administered via a 22 G venous catheter. A robust and reproducible inflammatory reaction with leukocyte invasion, upregulation of proinflammatory cytokines, and disruption of the alveolo-capillary barrier is induced within hours to days, depending on the LPS dosage used. Collection of blood samples, BAL fluid, and lung harvesting, as well as the processing for FACS analysis, are described in detail in the protocol. Although the use of the sterile LPS is not suitable to study pharmacologic interventions in infectious diseases, the described approach offers minimal invasiveness, simple handling, and good reproducibility to answer mechanistic immunological questions. Furthermore, dose titration as well as the use of alternative LPS preparations or mouse strains allow modulation of the clinical effects, which can exhibit different degrees of ALI severity or early vs. late onset of disease symptoms.

Presented here is a step-by-step procedure to induce acute lung injury in mice by direct intratracheal lipopolysaccharide instillation and to perform FACS analysis of blood samples, bronchoalveolar lavage fluid, and lung tissue. Minimal invasiveness, simple handling, good reproducibility, and titration of disease severity are advantages of this approach.

Airway administration of lipopolysaccharide (LPS) is a common way to study pulmonary inflammation and acute lung injury (ALI) in small animal models. ...