MG is supported by grants K08DK101608 and R03DK111473 from the National Institutes of Health, March of Dimes Foundation Grant No. 5-FY17-79, the Children&#39;s Discovery Institute of Washington University and St. Louis Children&#39;s Hospital and the Department of Pediatrics at Washington University School of Medicine, St. Louis. CJL is supported by R01DK104946 (PI: Silverman), the Children&#39;s Discovery Institute of Washington University and St. Louis Children&#39;s Hospital.

All animal procedures in this study were approved by either the Washington University in St. Louis Institutional Animal Care and Use Committee (Protocol 20160187) or University of Pittsburgh Institutional Animal Care and Use Committee (Protocol 14103918). Human fetal small intestine at less than 24-week gestation was obtained in accordance with the University of Pittsburgh anatomical tissue procurement guidelines after Institutional Review Board approval (protocol PRO14100537) from the University of Pittsburgh Health Sci...

<ol>
	<li>Patel, R. M., Denning, P. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Therapeutic+use+of+prebiotics,+probiotics,+and+postbiotics+to+prevent+necrotizing+enterocolitis:+what+is+the+current+evidence?.">Therapeutic use of prebiotics, probiotics, and postbiotics to prevent necrotizing enterocolitis: what is the current evidence?.</a> Clin Perinatol. 40 (1), 11-25 (2013).</li><li>Caplan, M. S., Jilling, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+concepts+in+necrotizing+enterocolitis.">New concepts in necrotizing enterocolitis.</a> Curr Opin Pediatr. 13 (2), 111-115 (2001).</li><li>Henry, M. C., Moss, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Necrotizing+enterocolitis.">Necrotizing enterocolitis.</a> Annu Rev Med. 60, 111-124 (2009).</li><li>Lin, P. W., Stoll, B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Necrotising+enterocolitis.">Necrotising enterocolitis.</a> Lancet. 368 (9543), 1271-1283 (2006).</li><li>Neu, J., Walker, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Necrotizing+enterocolitis.">Necrotizing enterocolitis.</a> N Engl J Med. 364 (3), 255-264 (2011).</li><li>Bartick, M., Reinhold, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+burden+of+suboptimal+breastfeeding+in+the+United+States:+a+pediatric+cost+analysis.">The burden of suboptimal breastfeeding in the United States: a pediatric cost analysis.</a> Pediatrics. 125 (5), e1048-e1056 (2010).</li><li>Bisquera, J. A., Cooper, T. R., Berseth, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+necrotizing+enterocolitis+on+length+of+stay+and+hospital+charges+in+very+low+birth+weight+infants.">Impact of necrotizing enterocolitis on length of stay and hospital charges in very low birth weight infants.</a> Pediatrics. 109 (3), 423-428 (2002).</li><li>Leaphart, C. L., 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=A+critical+role+for+TLR4+in+the+pathogenesis+of+necrotizing+enterocolitis+by+modulating+intestinal+injury+and+repair.">A critical role for TLR4 in the pathogenesis of necrotizing enterocolitis by modulating intestinal injury and repair.</a> J Immunol. 179 (7), 4808-4820 (2007).</li><li>Gribar, S. C., 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=Reciprocal+expression+and+signaling+of+TLR4+and+TLR9+in+the+pathogenesis+and+treatment+of+necrotizing+enterocolitis.">Reciprocal expression and signaling of TLR4 and TLR9 in the pathogenesis and treatment of necrotizing enterocolitis.</a> J Immunol. 182 (1), 636-646 (2009).</li><li>Good, 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=Amniotic+fluid+inhibits+Toll-like+receptor+4+signaling+in+the+fetal+and+neonatal+intestinal+epithelium.">Amniotic fluid inhibits Toll-like receptor 4 signaling in the fetal and neonatal intestinal epithelium.</a> Proceedings of the National Academy of Sciences. 109 (28), 11330-11335 (2012).</li><li>Good, 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=Breast+milk+protects+against+the+development+of+necrotizing+enterocolitis+through+inhibition+of+Toll-like+receptor+4+in+the+intestinal+epithelium+via+activation+of+the+epidermal+growth+factor+receptor.">Breast milk protects against the development of necrotizing enterocolitis through inhibition of Toll-like receptor 4 in the intestinal epithelium via activation of the epidermal growth factor receptor.</a> Mucosal Immunol. 8 (5), 1166-1179 (2015).</li><li>Yazji, I., 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+TLR4+activation+impairs+intestinal+microcirculatory+perfusion+in+necrotizing+enterocolitis+via+eNOS-NO-nitrite+signaling.">Endothelial TLR4 activation impairs intestinal microcirculatory perfusion in necrotizing enterocolitis via eNOS-NO-nitrite signaling.</a> Proc Natl Acad Sci U S A. , (2013).</li><li>Lundberg, J. O., Weitzberg, E., Gladwin, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+nitrate-nitrite-nitric+oxide+pathway+in+physiology+and+therapeutics.">The nitrate-nitrite-nitric oxide pathway in physiology and therapeutics.</a> Nat Rev Drug Discov. 7 (2), 156-167 (2008).</li><li>Bober-Olesinska, K., Kornacka, M. K. <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+glutamine+supplemented+parenteral+nutrition+on+the+incidence+of+necrotizing+enterocolitis,+nosocomial+sepsis+and+length+of+hospital+stay+in+very+low+birth+weight+infants.">Effects of glutamine supplemented parenteral nutrition on the incidence of necrotizing enterocolitis, nosocomial sepsis and length of hospital stay in very low birth weight infants.</a> Med Wieku Rozwoj. 9 (3 Pt 1), 325-333 (2005).</li><li>Li, 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=Glutamine+decreases+lipopolysaccharide-induced+intestinal+inflammation+in+infant+rats.">Glutamine decreases lipopolysaccharide-induced intestinal inflammation in infant rats.</a> Am J Physiol Gastrointest Liver Physiol. 286 (6), G914-G921 (2004).</li><li>Good, 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=The+human+milk+oligosaccharide+2'-fucosyllactose+attenuates+the+severity+of+experimental+necrotising+enterocolitis+by+enhancing+mesenteric+perfusion+in+the+neonatal+intestine.">The human milk oligosaccharide 2'-fucosyllactose attenuates the severity of experimental necrotising enterocolitis by enhancing mesenteric perfusion in the neonatal intestine.</a> Br J Nutr. 116 (7), 1175-1187 (2016).</li><li>Jantscher-Krenn, 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=The+human+milk+oligosaccharide+disialyllacto-N-tetraose+prevents+necrotising+enterocolitis+in+neonatal+rats.">The human milk oligosaccharide disialyllacto-N-tetraose prevents necrotising enterocolitis in neonatal rats.</a> Gut. 61 (10), 1417-1425 (2012).</li><li>Akin, I. 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=Oral+lactoferrin+to+prevent+nosocomial+sepsis+and+necrotizing+enterocolitis+of+premature+neonates+and+effect+on+T-regulatory+cells.">Oral lactoferrin to prevent nosocomial sepsis and necrotizing enterocolitis of premature neonates and effect on T-regulatory cells.</a> Am J Perinatol. 31 (12), 1111-1120 (2014).</li><li>Amin, H. 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=Arginine+supplementation+prevents+necrotizing+enterocolitis+in+the+premature+infant.">Arginine supplementation prevents necrotizing enterocolitis in the premature infant.</a> J Pediatr. 140 (4), 425-431 (2002).</li><li>Rodgers, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Practical+aspects+of+milk+collection+in+the+rat.">Practical aspects of milk collection in the rat.</a> Lab Anim. 29 (4), 450-455 (1995).</li><li>DePeters, E. J., Hovey, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+collecting+milk+from+mice.">Methods for collecting milk from mice.</a> J Mammary Gland Biol Neoplasia. 14 (4), 397-400 (2009).</li><li>Willingham, 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=Milk+collection+methods+for+mice+and+Reeves'+muntjac+deer.">Milk collection methods for mice and Reeves' muntjac deer.</a> J Vis Exp. (89), (2014).</li><li>Saxena, 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=Human+Intestinal+Enteroids:+a+New+Model+To+Study+Human+Rotavirus+Infection,+Host+Restriction,+and+Pathophysiology.">Human Intestinal Enteroids: a New Model To Study Human Rotavirus Infection, Host Restriction, and Pathophysiology.</a> J Virol. 90 (1), 43-56 (2015).</li><li>Zachos, N. C., 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+Enteroids/Colonoids+and+Intestinal+Organoids+Functionally+Recapitulate+Normal+Intestinal+Physiology+and+Pathophysiology.">Human Enteroids/Colonoids and Intestinal Organoids Functionally Recapitulate Normal Intestinal Physiology and Pathophysiology.</a> J Biol Chem. 291 (8), 3759-3766 (2016).</li><li>Drummond, C. 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=Enteroviruses+infect+human+enteroids+and+induce+antiviral+signaling+in+a+cell+lineage-specific+manner.">Enteroviruses infect human enteroids and induce antiviral signaling in a cell lineage-specific manner.</a> Proc Natl Acad Sci U S A. 114 (7), 1672-1677 (2017).</li><li>Ettayebi, 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=Replication+of+human+noroviruses+in+stem+cell-derived+human+enteroids.">Replication of human noroviruses in stem cell-derived human enteroids.</a> Science. 353 (6306), 1387-1393 (2016).</li></ol>

The intestinal epithelium is comprised of many cellular subtypes that are responsible for providing host defense against pathogens, maintaining gut barrier integrity, and can be breached in the pathogenesis of several diseases. While animal models can recapitulate some facets of the disease, the ex vivo model of enteroids derived from the small intestine of mice and humans provides a platform to test effects of various treatments. The significance of the enteroid model allows researchers to culture and different...

Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in premature infants, affecting nearly 1 in 10 infants born before 29 weeks gestation1,2,3. Half of the infants with NEC progress to the most severe form, where survival is only 10 - 30%4,5. In the United States, an estimated 2 - 3 billion USD/year are spent treating infants with NEC6,7, yet neither the survival rate nor therapy has changed over the past 30 years. The pathogenesis of NEC is characterized by intestinal injury and impaired mucosal healing8,9,10,11, however, the signaling pathways leading to an exacerbated inflammatory response and mechanisms to reverse the inflammation remain incompletely understood.
The administration of human breast milk has been found to be the only protective strategy against NEC for premature infants. We have previously shown that breast milk protects against NEC development through inhibition of the innate immune receptor toll-like receptor 4 (TLR4) in the intestinal epithelium via the epidermal growth factor receptor (EGFR) signaling pathway11. Supplementation of breast milk to an experimental NEC formula attenuated the inflammatory response seen in NEC as demonstrated by inhibition of enterocyte apoptosis and restoration of enterocyte proliferation in a manner that was dependent on epidermal growth factor (EGF) and EGFR11. In another study, it was shown that nitrate, another component of breast milk, contributes to its protective nature by modulating intestinal perfusion, as compared to infant formula, which is lacking nitrate and may contribute to the increased frequency of NEC in formula fed infants12,13. Other compounds present in breast milk that have been shown to be involved in the protection against NEC include human milk oligosaccharides, L-arginine, glutamine, and lactoferrin14,15,16,17,18,19. These beneficial elements of breast milk reveal the necessity of its use in the prevention of NEC, but also stress the importance of studying the mechanisms, signaling pathways, and cellular effects involved in how breast milk is mediating the protection against NEC.
In order to further study the protective properties of breast milk in a mouse model of NEC, we developed a novel, easy to use technique by which mouse breast milk can be extracted from an anesthetized dam using an electric human breast pump11,12. This strategy of acquiring mouse breast milk is advantageous, not only because human breast pumps are readily available and efficient in the procurement of breast milk, but also because this method allows for species-specific breast milk analyses. As a result, we can compare the effects of mouse breast milk with those of expressed human breast milk as well as pasteurized human donor milk from a milk bank in species-specific models. This technique allows for the study of breast milk components in relation to their contribution towards NEC prevention. Other investigators have developed breast milk extraction methods, however, these techniques are manual and typically require more than one lab member20,21,22. Here an easy technique that can be utilized by modifying a human electric breast pump to collect milk from a mouse is presented. This technique can also be applied to other species.
To adequately interrogate the signaling pathways involved with NEC, model systems are needed to evaluate all of the different cell types known to be affected in the disease process. Here, we discuss one such model system - enteroids - and their establishment from mouse and human small intestine. Human intestinal enteroids (HIEs) in particular provide significant promise, because they offer an innovative, genetically diverse ex vivo human model to aid in the study of pathophysiological processes that take place in the gastrointestinal tract23. Enteroids have been found to be cultured long-term and can be frozen for later use23, and unlike Human Intestinal Organoids (HIOs), whose cultures are developed from inducible pluripotent stem cells, enteroids are generated from stem cells within isolated intestinal crypts24. Enteroids require less maintenance, can be infected quickly25, and can be established easily since intestinal crypts are more differentiated than HIOs23. Therefore, HIEs offer many advantages over existing techniques because they can be developed to exhibit region-specific compositional and functional properties of the human gastrointestinal epithelium23. The use of enteroids is a highly effective choice when in need of a human model of the intestine, with adherence to region-specific limitations and ease-of-use. Here we demonstrate the technique of isolating and maintaining primary stem cell-derived small intestinal enteroids from mice and premature human infants.

<table>
	<tbody>
		<tr>
			<td>Dulbecco&#39;s Modified Eagle&#39;s Medium (DMEM) with 4.5 g/L Glucose and L-Glutamine</td>
			<td>Lonza</td>
			<td>12-604F</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Gibco</td>
			<td>26140-079</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>Humulin N (Insulin)</td>
			<td>Eli Lilly And Company</td>
			<td>0002-8315</td>
			<td></td>
		</tr>
		<tr>
			<td>1x Dulbecco&#39;s Phosphate-Buffered Saline (DPBS)</td>
			<td>Sigma-Aldrich</td>
			<td>D8537</td>
			<td></td>
		</tr>
		<tr>
			<td>Gentamicin</td>
			<td>Gibco</td>
			<td>15750-060</td>
			<td></td>
		</tr>
		<tr>
			<td>Amphotericin B</td>
			<td>Gibco</td>
			<td>15290-026</td>
			<td></td>
		</tr>
		<tr>
			<td>0.5 M Ethylenediaminetetraacetic acid (EDTA), pH 8.0</td>
			<td>Invitrogen</td>
			<td>15575-020</td>
			<td></td>
		</tr>
		<tr>
			<td>1x Advanced DMEM/F-12</td>
			<td>Invitrogen</td>
			<td>12634-028</td>
			<td></td>
		</tr>
		<tr>
			<td>200 mM L-Glutamine</td>
			<td>Gibco</td>
			<td>25030-081</td>
			<td></td>
		</tr>
		<tr>
			<td>1 M N-2-Hydroxyethylpiperazine-N-2-Ethane Sulfonic Acid (HEPES)</td>
			<td>Sigma-Aldrich</td>
			<td>H3537</td>
			<td></td>
		</tr>
		<tr>
			<td>N-Acetylcysteine</td>
			<td>Sigma-Aldrich</td>
			<td>A9165</td>
			<td></td>
		</tr>
		<tr>
			<td>100x N-2 Supplement</td>
			<td>Gibco</td>
			<td>17502-048</td>
			<td></td>
		</tr>
		<tr>
			<td>50x B-27 Supplement Minus Vitamin A</td>
			<td>Gibco</td>
			<td>08-0085SA</td>
			<td></td>
		</tr>
		<tr>
			<td>100x ROCK Inhibitor Y-27632, Dihydrochloride</td>
			<td>Sigma-Aldrich</td>
			<td>Y0503</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Mouse Wnt3a Protein</td>
			<td>R&#38;D Systems</td>
			<td>1324-WN</td>
			<td></td>
		</tr>
		<tr>
			<td>Murine Noggin</td>
			<td>PeproTech</td>
			<td>250-38</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Mouse R-Spondin 1</td>
			<td>R&#38;D Systems</td>
			<td>3474-RS</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Murine Epidermal Growth Factor (EGF)</td>
			<td>PeproTech</td>
			<td>315-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel Growth Factor Reduced Basement Membrane Matrix</td>
			<td>Corning</td>
			<td>356231</td>
			<td></td>
		</tr>
		<tr>
			<td>35 x 10 mm Cell Culture Petri Dish</td>
			<td>Eppendorf</td>
			<td>0030700112</td>
			<td></td>
		</tr>
		<tr>
			<td>24-Well Cell Culture Plate</td>
			<td>Eppendorf</td>
			<td>0030722116</td>
			<td></td>
		</tr>
		<tr>
			<td>48-Well Cell Culture Plate</td>
			<td>Eppendorf</td>
			<td>0030723112</td>
			<td></td>
		</tr>
		<tr>
			<td>8-Well Nunc Lab-Tek II Chamber Slide System</td>
			<td>Thermo Scientific</td>
			<td>154534</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL Conical Tube</td>
			<td>Corning</td>
			<td>352070</td>
			<td></td>
		</tr>
		<tr>
			<td>100 &#956;M Sterile Cell Strainer</td>
			<td>Fisher Scientific</td>
			<td>22-363-549</td>
			<td></td>
		</tr>
		<tr>
			<td>70 &#956;M Sterile Cell Strainer</td>
			<td>Fisher Scientific</td>
			<td>22-363-548</td>
			<td></td>
		</tr>
		<tr>
			<td>1x Phosphate-Buffered Saline (PBS), pH 7.2</td>
			<td>Invitrogen</td>
			<td>20012-027</td>
			<td></td>
		</tr>
		<tr>
			<td>16% Paraformaldehyde (PFA)</td>
			<td>Electron Microscopy Sciences</td>
			<td>15710</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>T8787</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Sigma-Aldrich</td>
			<td>P1379</td>
			<td></td>
		</tr>
		<tr>
			<td>Normal Donkey Serum (NDS)</td>
			<td>Sigma-Aldrich</td>
			<td>D9663</td>
			<td></td>
		</tr>
		<tr>
			<td>4&#39;,6-Diamidino-2-Phenylindole, Dihydrochloride (DAPI)</td>
			<td>Invitrogen</td>
			<td>D1306</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Cover Glass</td>
			<td>Fisher Scientific</td>
			<td>12-544-D</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal Microscope Leica TCS SP8 X</td>
			<td>Leica Microsystems</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Photoshop CS6</td>
			<td>Adobe Systems</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>18 G 1.5 Inch Needle</td>
			<td>Becton Dickinson</td>
			<td>305196</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Sigma-Aldrich</td>
			<td>792632</td>
			<td></td>
		</tr>
		<tr>
			<td>Oxytocin</td>
			<td>Sigma-Aldrich</td>
			<td>O3251</td>
			<td></td>
		</tr>
		<tr>
			<td>Human Double Electric Breast Pump</td>
			<td>Lansinoh</td>
			<td>044677530163</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL Round Bottom Test Tube</td>
			<td>Corning</td>
			<td>352058</td>
			<td></td>
		</tr>
		<tr>
			<td>Rubber Stoppers</td>
			<td>Frey Scientific</td>
			<td>560761</td>
			<td></td>
		</tr>
		<tr>
			<td>Ki67 Antibody</td>
			<td>Abcam</td>
			<td>AB15580</td>
			<td></td>
		</tr>
		<tr>
			<td>Human Mki67 primer F: 5&#39;-GACCTCAAACTGGCTCCTAATC-3&#39; R: 5&#39;-GCTGCCAGATAGAGTCAGAAAG-3&#39;</td>
			<td>Integrated DNA Technologies</td>
			<td>N/A</td>
			<td></td>
		</tr>
	</tbody>
</table>

breast milk enhances growth of enteroids: an ex vivo model of cell proliferation

Human small intestinal enteroids are derived from the crypts and when grown in a stem cell niche contain all of the epithelial cell types. The ability to establish human enteroid ex vivo culture systems are important to model intestinal pathophysiology and to study the particular cellular responses involved. In recent years, enteroids from mice and humans are being cultured, passaged, and banked away for future use in several laboratories across the world. This enteroid platform can be used to test the effects of various treatments and drugs and what effects are exerted on different cell types in the intestine. Here, a protocol for establishing primary stem cell-derived small intestinal enteroids derived from neonatal mice and premature human intestine is provided. Moreover, this enteroid culture system was utilized to test the effects of species-specific breast milk. Mouse breast milk can be obtained efficiently using a modified human breast pump and expressed mouse milk can then be used for further research experiments. We now demonstrate the effects of expressed mouse, human, and donor breast milk on the growth and proliferation of enteroids derived from neonatal mice or premature human small intestine.

We first sought to investigate whether expressed human breast milk or pasteurized donor breast milk had an effect on small intestinal enteroids. Indeed, human breast milk and donor breast milk increased the growth of neonatal mouse (Figure 1A) and premature human derived enteroids (Figure 1B).
Since human breast milk increased the growth of small intestinal enteroids, w...

Watch this Scientific Journal Video about Breast Milk Enhances Growth of Enteroids: An Ex Vivo Model of Cell Proliferation at JoVE.com

Breast Milk Enhances Growth of Enteroids: An Ex Vivo Model of Cell Proliferation

This protocol describes how to establish an enteroid culture system from neonatal mouse or premature human intestine as well as an efficient method to collect milk from mice.

Breast Milk Enhances Growth of Enteroids: An Ex Vivo Model of Cell Proliferation

Human small intestinal enteroids are derived from the crypts and when grown in a stem cell niche contain all of the epithelial cell types. The ability to ...

The overall goal of this procedure is to culture miniature guts, called enteroids, in the laboratory. Enteroids are treated with mouse breast milk extracted in the laboratory to elucidate the effects of breast milk on proliferation in vitro. This method can help answer key questions related to various gastrointestinal diseases, such as necrotizing enterocolitis, which affects premature infants.The main advantage of this technique is that enteroids require little maintenance, can be established quickly, and exhibit many of the functional properties of the gastrointestinal epithelium. This technique of establishing enteroids is a highly effective model of the human small intestine. Though this method can provide insight into the small intestine, it can also be applied to other organ systems in other regions of the GI tract.To begin, thaw solubilized basement membrane extract on ice. Then, use scissors and forceps to make a vertical incision down the entire abdominal mid-line of a euthanized mouse. Using forceps, excise the small intestine and remove the mesentery.To prepare the small intestine for crypt isolation and enteroid creation, position the intestine straight and use scissors to cut longitudinally along its entire length. Remove any stool by gently shaking the intestine with forceps in a Petri dish filled with PBS antibiotic mixture. Then, add 30 milliliters of cell disruption media number one to a 50 milliliter conical tube.Place half centimeter segments of intestine into the tube and set the tube into an ice bucket on a shaker. In a hood, add 9 microliters of basement membrane to the bottom of each well in an eight well chamber slide. Quickly spread the membrane with a pipette tip and allow the basement membrane to polymerize in an incubator.It is important to to quickly spread the basement membrane so that it forms a thin layer on the bottom of the well. The crypts will not attach if there are air bubbles present or if the basement membrane is too thick. After agitating the conical tube, use a 100 micrometer strainer to filter the membrane tissue and discard the flow-through.Add 30 milliliters of cell disruption media number two to a new 50 milliliter conical tube, and then, add the intestinal tissue to the tube. After agitating the tube for 15 minutes, filter the tissue through a 100 micrometer strainer. Keep the flow-through from this step.Add 15 milliliters of TMEM with 4.5 grams per liter glucose and L-glutamine to a new conical tube. Remove tissue from the 100 micrometer strainer and add it to the new conical tube. Then, manually shake the tube for 10 seconds and filter through a 100 micrometer strainer.In the hood, use a 70 micrometer strainer to filter the tissue into a new conical tube. After centrifuging the tube for 8 minutes, place it in an ice bucket in the hood. Use a pipette to carefully remove the supernatant without disturbing the formed pellet.Re-suspend the pellet with an appropriate amount of crypt culture media without growth factors. After incubating the chamber slide for 30 minutes, plate the crypt medium mixture directly onto the basement membrane and incubate at 37 degrees Celsius for 3 hours while the crypts adhere. After the incubation period, use a P200 pipette to carefully remove any media and unattached crypts.Another critical step is to make sure to slowly remove the media and excess crypts that failed to attach using a P200 pipette. Do not disturb the basement membrane, as the attached crypts can become dislodged. Slowly add 250 microliters of crypt culture media with growth factors to each well.Anesthetize a lactating dam with isoflurane delivered via nose cone and administer the appropriate dose of subcutaneous oxytocin. Clean teats with 70%ethanol and allow them to dry before initiating the milking procedure. Using an electric human breast pump outfitted with silicone tubing sized to fit mice and a 5 milliliter tube, extract milk from the teats one at a time.Finally, aliquot the milk immediately and store at minus 80 degrees Celsius. Treat the enteroids on day five with stored mouse breast milk for 24 hours at 37 degrees Celsius. On the first day of staining, use PBS to remove experimental treatments and wash the enteroids.Add 250 microliters of 4%PFA to each well and place the slide on a rotator for 1 to 2 hours at 4 degrees Celsius. Use a pipette to remove the PFA and then gently wash each well four times with 250 microliters of PBS. Place the chamber slide on a rotator for 10 minutes at room temperature.Add 250 microliters of 0.1%Triton X-100 to each well and incubate for 1 hour at room temperature. After incubating, remove the Triton X-100 with a pipette and wash four times with 250 microliters of PBS in each well. Place the slide on a rotator for 15 minutes at room temperature.Add 250 microliters of 10%NDS/PBST to each well and incubate for 45 minutes at room temperature. After incubation, remove the NDS/PBST with a pipette. Finally, add 250 microliters of diluted primary antibody to each well and incubate overnight at 4 degrees Celsius.On the second day of staining, wash each well at least five times with 250 microliters of PBST and place the slide on a rotator at 4 degrees Celsius between each wash. Add 250 microliters of diluted secondary antibody in 1%NDS/PBST to each well. Wrap the slide in foil and incubate overnight at 4 degrees Celsius.On the final day of staining, add 250 microliters of nuclear stained DAPI to each well and allow it to sit for 15 minutes. Then, wash each well six times with 250 microliters of PBST. Place the slide on a rotator for 10 minutes at 4 degrees Celsius between each wash.Finally, prepare the slide for microscopic imaging by mounting a cover slip on the chamber slide with mounting media and allowing it to dry for 24 hours. In this study, small intestinal enteroids derived from neonatal mice were treated with breast milk collected from lactating mice. As shown in this figure, mouse breast milk increased proliferation in mouse enteroids.To investigate species-specific effects of breast milk, human breast milk and the pasteurized donor breast milk were also applied to the mouse enteroids. As shown in this figure, human and pasteurized donor breast milk increased proliferation of mouse enteroids. While attempting this procedure, it's important to keep the crypts on ice during the isolation steps.Slowly and gently perform all methods after the enteroids are in culture. Following this procedure, other methods like treatments with immune cells, microbiota, or various drugs can be performed in order to answer additional questions to better recapitulate the microenvironment of the intestine. After watching this video, you should have a good understanding of how to culture, treat, and perform immunofluorescence on the enteroids.In addition, you should be able to efficiently extract breast milk from a lactating mouse. Don't forget that working with human tissue and bodily fluids can be extremely hazardous, and personal protective equipment should always be worn while performing these procedures.

breast-milk-enhances-growth-enteroids-an-ex-vivo-model-cell

Research

JoVE Journal

Medicine

19.3K Views.  Washington University School of Medicine. The overall goal of this procedure is to culture miniature guts, called enteroids, in the laboratory. Enteroids are treated with mouse breast milk extracted in the laboratory to elucidate the effects of breast milk on proliferation in vitro. This method can help answer key questions related to various gastrointestinal diseases, such as necrotizing enterocolitis, which affects premature infants.The main advantage of this technique is that enteroids require little maintenance, can be est...