This work was supported by grant from NIDDK (DK065949 for GG). We thank Dr. Brenda M. Jarvis and Jeff Duryea Jr. for reading the manuscript.

Animal usage follows the procedures specified in protocol M/11/181 approved by the Vanderbilt Institutional Animal Care and Use Committee for Gu. CD1 or CBA/Bl6 mice were purchased from commercial vendors and crossed in the Vanderbilt animal facility to obtain neonatal mice.
1. Preparation of Mice, Stock Solutions, and Equipment
<ol>
	<li>For the mouse cross: set up a mouse cross and record the plugging dates to aid experimental planning. CD1 mice usually give birth around day 19 after matin...

<ol>
	<li>Matsumoto, 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=Improvement+of+pancreatic+islet+cell+isolation+for+transplantation.">Improvement of pancreatic islet cell isolation for transplantation.</a> Proc (Bayl Univ Med Cent). 20 (4), 357-362 (2007).</li><li>Zmuda, E. J., Powell, C. A., Hai, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+murine+islet+isolation+and+subcapsular+kidney+transplantation.">A method for murine islet isolation and subcapsular kidney transplantation.</a> J Vis Exp. (50), (2011).</li><li>Zhao, 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=Galphao+represses+insulin+secretion+by+reducing+vesicular+docking+in+pancreatic+beta-cells.">Galphao represses insulin secretion by reducing vesicular docking in pancreatic beta-cells.</a> Diabetes. 59 (10), 2522-2529 (2010).</li><li>Planas, 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=Gene+expression+profiles+for+the+human+pancreas+and+purified+islets+in+type+1+diabetes:+new+findings+at+clinical+onset+and+in+long-standing+diabetes.">Gene expression profiles for the human pancreas and purified islets in type 1 diabetes: new findings at clinical onset and in long-standing diabetes.</a> Clin Exp Immunol. 159 (1), 23-44 (2010).</li><li>Tonne, J. 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=Global+gene+expression+profiling+of+pancreatic+islets+in+mice+during+streptozotocin-induced+beta-cell+damage+and+pancreatic+Glp-1+gene+therapy.">Global gene expression profiling of pancreatic islets in mice during streptozotocin-induced beta-cell damage and pancreatic Glp-1 gene therapy.</a> Dis Model Mech. 6 (5), 1236-1245 (2013).</li><li>London, N. J., Swift, S. M., Clayton, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation,+culture+and+functional+evaluation+of+islets+of+Langerhans.">Isolation, culture and functional evaluation of islets of Langerhans.</a> Diabetes Metab. 24 (3), 200-207 (1998).</li><li>Rorsman, 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=Failure+of+glucose+to+elicit+a+normal+secretory+response+in+fetal+pancreatic+beta+cells+results+from+glucose+insensitivity+of+the+ATP-regulated+K++channels.">Failure of glucose to elicit a normal secretory response in fetal pancreatic beta cells results from glucose insensitivity of the ATP-regulated K+ channels.</a> Proc Natl Acad Sci U S A. 86 (12), 4505-4509 (1989).</li><li>Hellerstrom, C., Swenne, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+maturation+and+proliferation+of+fetal+pancreatic+beta-cells.">Functional maturation and proliferation of fetal pancreatic beta-cells.</a> Diabetes. 40 (Suppl 2), 89-93 (1991).</li><li>Blum, 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=Functional+beta-cell+maturation+is+marked+by+an+increased+glucose+threshold+and+by+expression+of+urocortin+3.">Functional beta-cell maturation is marked by an increased glucose threshold and by expression of urocortin 3.</a> Nat Biotechnol. 30 (3), 261-264 (2012).</li><li>Hegre, O. D., 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=Nonenzymic+in+vitro+isolation+of+perinatal+islets+of+Langerhans.">Nonenzymic in vitro isolation of perinatal islets of Langerhans.</a> In Vitro. 19 (8), 611-620 (1983).</li><li>Dolen&#353;ek, J., Rupnik, M. A., Sto&#382;er, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+similarities+and+differences+between+the+human+and+the+mouse+pancreas.">Structural similarities and differences between the human and the mouse pancreas.</a> Islets. 7 (1), e102445 (2015).</li><li>White, J., White, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Source Book of Enzymes, Source Book of Enzymes. , (1997).</li><li>Bock, T., Pakkenberg, B., Buschard, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+background+determines+the+size+and+structure+of+the+endocrine+pancreas.">Genetic background determines the size and structure of the endocrine pancreas.</a> Diabetes. 54 (1), 133-137 (2005).</li><li>Bouwens, L., Rooman, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+pancreatic+beta-cell+mass.">Regulation of pancreatic beta-cell mass.</a> Physiol Rev. 85 (4), 1255-1270 (2005).</li></ol>

The authors declare no competing financial interests for the described work.

Here, we provide a step-by-step protocol on islet isolation from pancreata that are too small for conventional perfusion. It is expected to yield islets ready for all islet-based studies such as beta-cell purification, gene expression analysis, islet beta-cell maturation, proliferation, cell stress responses, cell survival, metabolism, and functional GSIS maintenance, etc. This will be, to the best of our knowledge, the first detailed visual protocol that guides new researchers to perform islet isolation from ne...

Isolating pure pancreatic islets is essential for assaying glucose stimulated insulin secretion (GSIS) of beta cells and for islet transplantation from cadaveric donors 1-3. It is also necessary to establish endocrine gene expression in islet cells 4, 5. For this purpose, detailed protocols have been established to allow for isolation of pancreatic islets from large pancreata (6 and references therein). These methods are based on enzymatic perfusion to dissociate acinar from islet tissues, coupled with gradient separation and hand picking. Thus, islet isolation from large pancreas can be performed readily in most laboratories. On the other hand, no detailed step-by-step protocol exists to allow for the isolation of islets from pancreata that are too small to perfuse.
Studying gene expression and function of neonatal islets is important. Neonate islets have different properties from adults in insulin secretion and proliferation capability 7, 8. However, isolating islets from newly born animals, especially mice is challenging due to the small size of the newly born pancreas. The size prevents the usual perfusion process when collagenase is injected though the pancreatic duct. Indeed, several papers have presented studies along these lines, with enzyme or non-enzyme aided isolation procedures 7, 9, 10. However, detailed description of the islet isolation process with visual aid is lacking 7, 9, making it a challenge for most researchers to perform similar studies. 
We have explored several different conditions that yield high quality islets from neonatal mice. Here we present a protocol that is expected to help researchers learn the key details in the islet isolation process. This protocol is applicable to mouse pancreas up to two weeks of age, after which perfusion can be performed for routine islet isolation. Islets can be directly used for insulin secretion and gene expression assays.

<table border="0" cellpadding="0" cellspacing="0" width="769">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Collagenase&#160; Type IV</td>
			<td style="width:253px;">Sigma Aldrich, St Louis, MO</td>
			<td style="width:128px;">C5138</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="61">
			<td height="61" style="height:61px;width:169px;">1X HBSS with Ca2+/Mg2+</td>
			<td style="width:253px;">Mediatech/Cellgro, Manassas, VA</td>
			<td>MT21020CV</td>
			<td style="width:219px;">If HBSS wihout Ca2+/Mg2+ is obtained, CaCl2 and MgSO4 can be added to 1.26 and 0.5 mM, respectively.&#160;</td>
		</tr>
		<tr height="51">
			<td height="51" style="height:51px;width:169px;">RPMI 1640 w/o glucose</td>
			<td style="width:253px;">Thermo Fisher Scientific/Life Technologies, Waltham, MA</td>
			<td>11879-020</td>
			<td style="width:219px;">Glucose needs to be added to specific levels to not interfere with seusequent islet usage.&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Glucose</td>
			<td style="width:253px;">Sigma Aldrich, St Louis, MO</td>
			<td>G-7021&#160;</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:169px;">polysucrose and sodium diatrizoate solution</td>
			<td style="width:253px;">Sigma Aldrich, St Louis, MO</td>
			<td>Histopaque-10771</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Stereoscope</td>
			<td style="width:253px;">Carl-Zeiss, Oberkochen, Germany</td>
			<td>Stemi2000</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Stereoscope</td>
			<td style="width:253px;">Leica, Wetzlar, Germany</td>
			<td>Leica M165</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Microcentrifuge</td>
			<td style="width:253px;">Eppendorf, Hauppauge, NY</td>
			<td>Centrifuge 5417C</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Centrfuge</td>
			<td style="width:253px;">Eppendorf, Hauppauge, NY</td>
			<td>Centrifuge 5810R</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">15-ml centrfuge tubes&#160;</td>
			<td style="width:253px;">VWR, Radnor, PA</td>
			<td>89039-666</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">50-ml centrfuge tubes&#160;</td>
			<td style="width:253px;">VWR, Radnor, PA</td>
			<td>89039-658</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Precision balance</td>
			<td style="width:253px;">VWR, Radnor, PA</td>
			<td>VWR-225AC</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Microfuge tubes</td>
			<td style="width:253px;">VWR, Radnor, PA</td>
			<td>87003-294</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Pipetman P1000</td>
			<td style="width:253px;">Fisher Scientific,&#160; Waltham, MA</td>
			<td>F123602</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Pipetman P20</td>
			<td style="width:253px;">Fisher Scientific,&#160; Waltham, MA</td>
			<td>F123600</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">100X15 millimeter dish</td>
			<td style="width:253px;">VWR, Radnor, PA</td>
			<td>25384-088</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">60X15 millimeter dish</td>
			<td style="width:253px;">VWR, Radnor, PA</td>
			<td>25384-168</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:169px;">12-well plates</td>
			<td style="width:253px;">VWR, Radnor, PA</td>
			<td>665-180</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:169px;">Scissor</td>
			<td style="width:253px;">Fine Scientific Tools, Foster City, CA</td>
			<td>14080-11</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:169px;">Tweezers</td>
			<td style="width:253px;">Fine Scientific Tools, Foster City, CA</td>
			<td>5708-5</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:169px;">CD1 mice</td>
			<td style="width:253px;">Charles River Laboratories, Wilminton, MA&#160;</td>
			<td>CD-1</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;width:169px;">C57BL/6J</td>
			<td style="width:253px;">The Jackson laboratory, Farmington, CT&#160;</td>
			<td>C57BL/6J</td>
			<td style="width:219px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:169px;">B6CBAF1/J</td>
			<td style="width:253px;">The Jackson laboratory, Farmington, CT&#160;</td>
			<td>B6CBAF1/J</td>
			<td style="width:219px;"></td>
		</tr>
	</tbody>
</table>

effective isolation of functional islets from neonatal mouse pancreas

Perfusion-based islet-isolation protocols from large mammalian pancreata are well established. Such protocols are readily conducted in many laboratories due to the large size of the pancreatic duct that allows for ready collagenase injection and subsequent tissue perfusion. In contrast, islet isolation from small pancreata, like that of neonatal mice, is challenging because perfusion is not readily achievable in the small pancreata. Here we describe a detailed simple procedure that recovers substantial numbers of islets from newly born mice with visual assistance. Freshly dissected whole pancreata were digested with 0.5 mg/mL collagenase IV dissolved in Hanks&#39; Balanced Salt Solution (HBSS) at 37 &#176;C, in microcentrifuge tubes. Tubes were tapped regularly to aid tissue dispersal. When most of the tissue was dispersed to small clusters around 1 mm, lysates were washed three to four times with culture media with 10% fetal bovine serum (FBS). Islet clusters, devoid of recognizable acinar tissues, can then be recovered under dissecting stereoscope. This method recovers 20 - 80 small- to large-sized islets per pancreas of newly born mouse. These islets are suitable for most conceivable downstream assays, including insulin secretion, gene expression, and culture. An example of insulin secretion assay is presented to validate the isolation process. The genetic background and degree of digestion are the largest factors determining the yield. Freshly made collagenase solution with high activity is preferred, as it aids in endocrine-exocrine isolation. The presence of cations [calcium (Ca2+) and magnesium (Mg2+)] in all solutions and fetal bovine serum in the wash/picking media are necessary for good yield of islets with proper integrity. A dissecting scope with good contrast and magnification will also help.

Under optimal conditions, the presented method can yield 20 - 80 islets from each small mouse pancreas. This number depends on the genetic background, age of mice, and the size of islets to be recovered. Among the commonly used, CD1 out-bred and C57BL/6J pure-bred mice produce less islets with smaller size than hybrids between CD1 and C57BL/6 or commercial B6CBAF1/J mice do. Direct hand picking generally gave a smaller number of islets, likely due to the exclusion of small islets that cou...

Watch this Scientific Journal Video about Effective Isolation of Functional Islets from Neonatal Mouse Pancreas at JoVE.com

Effective Isolation of Functional Islets from Neonatal Mouse Pancreas

We describe a protocol herein for isolating intact islets from neonatal mice. Pancreata were partially digested with collagenase, followed by washing and hand picking. 20 - 80 islet clusters can be obtained per pancreas from newly born mice, which are suitable for several islet studies.

Perfusion-based islet-isolation protocols from large mammalian pancreata are well established. Such protocols are readily conducted in many laboratories ...

The overall goal of this procedure is to isolate intact islets of Langerhans from the neonatal mouse pancreas. This method can help answer the key questions in adding development and function. Such as insulin excretion, gene expression, para cell survival and functional maintenance.The main advantage of this method is that it's simple and straight forward while still allowing new researchers to isolate a substantial number of intact islet for down strain studies. Begin by spraying a neonate in the supine position with 70%ethanol. Then, use tweezers to lift the skin over the abdomen and cut the skin and muscle layers longitudinally along the midline from the genitals to the ribcage.Next, transfer all of the internal organs into a 100 centimeter dish and locate the pancreas, which is a white scattered organ with the ventral portion that clings to the duodenum and the dorsal portion that clings to the stomach and spleen. Add HBSS to dish to submerge the organs so that the pancreatic tissues no longer cling to the duodenum, stomach, or spleen. Then use a pair of tweezers to peel the pancreas away from surrounding tissues.Transfer the pancreas into a new 60 millimeter dish containing HBSS and use scissors to cut one to five pancreata into five millimeter pieces or smaller. When all of the tissue has been minced, transfer the pieces into one point five milliliter microcentrifuge tubes and add collagenase working solutions to the samples. Then incubate the tissue fragments at 37 degrees celsius, inverting the tubes two times every minute.After five minutes, tap the tube to monitor the digestion status of the pieces. Continue the digestion for another ten minutes, until the lysate is cloudy and most of the pancreata appear as fragmented cell clusters less than two millimeters in diameter. At the end of the digestion, pellet the lysate by microcentrifugation and use a p1000 pipette to carefully remove the supernatent, which should appear turbid but free of cell clusters.Next, add one millileter of fresh RPMI 16/40 complete medium to the pellet. Then gently tap to resuspend the fragmented lysate pieces and invert the tube ten times. After centrifuging, invert the resuspended lysate at least two more times as just demonstrated until the supernatent is clear.Then resuspend the final pellet in one milliliter of fresh complete medium and add two milliliters of polysucrose and sodium diatrazoate at a 1.077 g/ml density to a 15 milliliter conical tube on ice. Using a Pasteur pipette, carefully layer the lysate on top of the gradient solution without mixing the layers and separate the cells by centrifugation. Transfer the medium and the islet containing interphase layers into a new 15 milliliter tube and gently but thoroughly mix the islets with ten milliliters of fresh medium for centrifugation.After a second wash and fresh complete medium, resuspend the islet and duct containing pellet in four milliliters of fresh complete medium. Now seed the islets onto a 60 millimeter dish and add five milliliters of complete medium to the cells. Transfer the dish under a dissecting microscope and turn on the bright field illumination adjusting the light intensity to approximately 50%of the maximum power.At a 50x magnification, the islets will appear as slightly pink clusters and the acinar cells and dark, irregularly shaped clusters. Using a p20 pipette tip, harvest the individual islets, taking care to avoid the acinar clusters, dispensing the islet enriched fractions in a new 60 millimeter dish containing complete medium. When all of the islets have been picked from the original dish, harvest the islets from the collection dish into a new 60 millimeter dish containing four milliliters of fresh complete medium two more times, until only pure islets are present in the final collection dish.A proper digestion and isolation will yield islets with smooth outer surfaces. Insufficient collagenase digestion can result in large, easily visualized islets that can not be completely separated from the acinar tissues, reducing the overall islet yield even though larger islets are produced. In the case of over digestion, although acinar tissues can be completely separated from the islets, islet structure is prone to be compromised resulting in rough surface islets observed under the microscope.Neonatal islets isolated by this method display high basal insulin secretion levels with glucose stimulated insulin secretion profiles typical of immature islet beta cells, suggesting that this islet isolation procedure largely conserves the functional properties of neonatal islets. Once mastered, this technique can be finished within just two hours if performed properly. When attempting the procedure, it is important to remember to precentrifuge the collagenase in order to remove any insoluble debris and to calcium and magnesium supplemented washing buffer and to use pretreated washing buffer in order to stop the tissue dissociation quickly.For in this procedure, our experiment, such as glucose stimulated insulin secretion can be performed to answer additional questions such as insulin secretion dynamics in neonatal beta cells. Also, this technique pave ways for researchers in the field of beta cell biology to do additional essays, such as gene expression or other metabolic studies. After watching this video, you should have a good understanding of how to isolate intact islets from neonatal mouse pancreas for your down strain studies.Don't forget, working with collagenase powder will be extremely hazardous, so precautions such as wearing gloves and face mask should be always taken when using this material.

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9.9K visualizações.  Vanderbilt University Medical School. The overall goal of this procedure is to isolate intact islets of Langerhans from the neonatal mouse pancreas. This method can help answer the key questions in adding development and function. Such as insulin excretion, gene expression, para cell survival and functional maintenance.The main advantage of this method is that it's simple and straight forward while still allowing new researchers to isolate a substantial number of intact islet for down strain studies. Begin by spraying a ne...