Name: a simple high efficiency protocol for pancreatic islet isolation from mice
Uploaded: 2019-08-30T12:30:00
Description: Watch this Scientific Journal Video about A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice at JoVE.com

We are extremely grateful to Ms. Jennifer Munguia for her artistic illustration of the schematic diagram. We thank Mr. Michael R. Honig at Houston&rsquo;s Community Public Radio Station KPFT for his editorial assistance. This study was supported by American Diabetes Association #1-15-BS-177 (YS), and NIH R56DK118334/R01DK118334 (YS). This work was also supported by the USDA National Institute of Food and Agriculture, Hatch project 1010840 (YS) and R01 DK095118 (SG).

All methods described here have been approved by the Animal Care and Use Committee (ACUC) of Texas A&#38;M University. The surgical tools need is shown in Figure 1 and the schematic diagram of the procedure is shown in Figure 2.
1. Solutions
<ol>
	<li>Prepare Hank&#8217;s Balanced Salt Solution (HBSS) by adding 100 mL of 10X HBSS (from stock) to 900 mL of distilled water to make 1 L HBSS (1X).</li>
	<li>Prepare STOP solution (must b...

<ol>
	<li>Carter, J. D., Dula, S. B., Corbin, K. L., Wu, R., Nunemaker, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+guide+to+rodent+islet+isolation+and+assessment.">A practical guide to rodent islet isolation and assessment.</a> Biological Procedures Online. 11, 3-31 (2009).</li><li>Gotoh, M., Maki, T., Kiyoizumi, T., Satomi, S., Monaco, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+method+for+isolation+of+mouse+pancreatic+islets.">An improved method for isolation of mouse pancreatic islets.</a> Transplantation. 40 (4), 437-438 (1985).</li><li>O'Dowd, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+isolation+and+purification+of+rodent+pancreatic+islets+of+Langerhans.">The isolation and purification of rodent pancreatic islets of Langerhans.</a> Methods in Molecular Biology. 560, 37-42 (2009).</li><li>Do, O. H., Low, J. T., Thorn, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lepr(db)+mouse+model+of+type+2+diabetes:+pancreatic+islet+isolation+and+live-cell+2-photon+imaging+of+intact+islets.">Lepr(db) mouse model of type 2 diabetes: pancreatic islet isolation and live-cell 2-photon imaging of intact islets.</a> Journal of Visualized Experiments : JoVE. (99), e52632 (2015).</li><li>Stull, N. D., Breite, A., McCarthy, R., Tersey, S. A., Mirmira, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+islet+of+Langerhans+isolation+using+a+combination+of+purified+collagenase+and+neutral+protease.">Mouse islet of Langerhans isolation using a combination of purified collagenase and neutral protease.</a> Journal of Visualized Experiments : JoVE. (67), (2012).</li><li>Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+Differences+in+Islet+Distribution+in+the+Human+Pancreas+-+Preferential+Beta-Cell+Loss+in+the+Head+Region+in+Patients+with+Type+2+Diabetes.">Regional Differences in Islet Distribution in the Human Pancreas - Preferential Beta-Cell Loss in the Head Region in Patients with Type 2 Diabetes.</a> PLOS ONE. 8, (2013).</li><li>Li, D. S., Yuan, Y. H., Tu, H. J., Liang, Q. L., Dai, L. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+protocol+for+islet+isolation+from+mouse+pancreas.">A protocol for islet isolation from mouse pancreas.</a> Nature Protocols. 4 (11), 1649-1652 (2009).</li><li>Neuman, J. C., Truchan, N. A., Joseph, J. W., Kimple, M. E. <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+mouse+pancreatic+islet+isolation+and+intracellular+cAMP+determination.">A method for mouse pancreatic islet isolation and intracellular cAMP determination.</a> Journal of Visualized Experiments : JoVE. (88), e50374 (2014).</li><li>Scharp, D. W., Lacy, P. E., Finke, E., Olack, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-temperature+culture+of+human+islets+isolated+by+the+distention+method+and+purified+with+Ficoll+or+Percoll+gradients.">Low-temperature culture of human islets isolated by the distention method and purified with Ficoll or Percoll gradients.</a> Surgery. 107 (5), e50374 (1987).</li><li>Salvalaggio, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Islet+filtration:+a+simple+and+rapid+new+purification+procedure+that+avoids+ficoll+and+improves+islet+mass+and+function.">Islet filtration: a simple and rapid new purification procedure that avoids ficoll and improves islet mass and function.</a> Transplantation. 74 (66), 877-879 (2002).</li><li>Saliba, Y., Bakhos, J. J., Itani, T., Fares, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+optimized+protocol+for+purification+of+functional+islets+of+Langerhans.">An optimized protocol for purification of functional islets of Langerhans.</a> Laboratory Investigation. 97 (1), 70-83 (2017).</li><li>Pradhan, 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=Obestatin+stimulates+glucose-induced+insulin+secretion+through+ghrelin+receptor+GHS-R.">Obestatin stimulates glucose-induced insulin secretion through ghrelin receptor GHS-R.</a> Scientific Reports. 7 (1), 979 (2017).</li><li>Shapiro, A. M. J., Hao, E., Rajotte, R. V., Kneteman, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+yield+of+rodent+islets+with+intraductal+collagenase+and+stationary+digestion--a+comparison+with+standard+technique.">High yield of rodent islets with intraductal collagenase and stationary digestion--a comparison with standard technique.</a> Cell Transplantation. 5 (6), 631-638 (1996).</li></ol>

This protocol includes collagenase perfusion and digestion, followed by purification of islets. The most critical steps of this protocol are effective injection and complete perfusion of the pancreas1,4,7. The delivery method of this protocol allows the enzyme to traverse the anatomical routes to better digest the exocrine tissue surrounding the islets1. In addition, this technique is well suited for comp...

There are two common methods in the literature for pancreatic islet isolation. One requires excising the pancreas and dicing it into small pieces using surgical scissors, and then digesting it in a collagenase solution1,2,3. Another more precise method is to use the network of ducts present in the pancreas to introduce digestive enzyme. The following sites have been used for digestive enzyme injection: the junction of the bile and cystic duct, the gallbladder into the common bile duct, or the common bile duct itself1,4,5. It is known that islets are not evenly distributed in the pancreas; the splenic region contains the most islets6. While the second method using anatomical routes to deliver digestive enzymes allows for a more complete perfusion of the pancreas, including the splenic region, this procedure often requires clamping or suturing of the ampulla of Vater that is technically challenging. In terms of islet purification, multiple density gradients, as well as cell strainers and magnetic retraction have been used to purify the islets3,7. The utilization of these gradients can be time consuming and the Ficoll gradients can result in toxic damage of islets8.
The current protocol is built on the method described by Li et al.7, with additional modifications added based on the experience of ourselves and others1,4. The most critical steps of our protocol are clamping of the common bile duct near the liver end, injecting collagenase P via the ampulla of Vater to digest the exocrine tissue, and then using a shaking water bath to expedite the digestion mechanically1,4,7. Subsequently, a 'STOP' solution is applied to inhibit further digestion of the islets; HBSS is used to wash off the remaining collagenase P and STOP solution. When the Ficoll method was used to purify human islets, yield was reported to be twice the islets with greater functional capability (e.g., insulin secretion) as compared to the use of Percoll gradients9. However, studies have questioned the use of Ficoll gradient due to its toxic effect on the islets1,10. It has been reported that the Histopaque gradient provides optimal purification kinetics for mouse islet isolation, which produces good yield of high quality islets with simpler steps and lower cost1. In our protocol, Histopaque-1077 is used to purify islets from other residual tissue8,11. The harvested islets can be cultured in complete RPMI-1640 media, or directly utilized in RNA/protein quantitation.
Our protocol, using a combination of collagenase P digestion and a single gradient purification step, is simpler than other published protocols. Our method does not require demanding surgical procedures and has just a few simple steps. More importantly, this protocol consistently produces a good yield of high quality functional islets (250-350/mouse) as we reported12.

<table>
	<tbody>
		<tr>
			<td>3 mL syringe</td>
			<td>BD</td>
			<td>309657</td>
			<td>Hoding collagenase P</td>
		</tr>
		<tr>
			<td>Coverglass forceps</td>
			<td>VWR</td>
			<td>82027-396</td>
			<td>Holding skin of mouse to aid incision procedure</td>
		</tr>
		<tr>
			<td>Curved forceps</td>
			<td>Sigma-Aldrich</td>
			<td>Z168696</td>
			<td>Holding tissues during pancreas removal</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Piramal</td>
			<td>B13B16A</td>
			<td>To anaesthetize mice prior surgery</td>
		</tr>
		<tr>
			<td>100 mm petri dishes</td>
			<td>VWR</td>
			<td>30-2041</td>
			<td>Used for islet culture</td>
		</tr>
		<tr>
			<td>30 G. &#189; inch needle</td>
			<td>BD</td>
			<td>305106</td>
			<td>For penetration of Ampulla of vater to deliver Collagenase P - this guage is used as it fits well in most CBDs</td>
		</tr>
		<tr>
			<td>50ml tube</td>
			<td>VWR</td>
			<td>89039-658</td>
			<td>Holding digested pancreatic tissue, collagenase P, and purified islets</td>
		</tr>
		<tr>
			<td>Absorbent pads with waterproof moisture barrier</td>
			<td>VWR</td>
			<td>82020-845</td>
			<td>To absorb blood from syurgical procesdudes</td>
		</tr>
		<tr>
			<td>Centrifuge 5810R with swing bucket and deceleration capability</td>
			<td>Eppendorf</td>
			<td>5811FJ478114</td>
			<td>Use for pelleting tissues, pellet is formed at bottom of conical tube - swing bucket centrifuge is needed. Also the decelaration feature is important to form the gradient layers.</td>
		</tr>
		<tr>
			<td>Collagenase P- 1g</td>
			<td>Roche Diagnostics</td>
			<td>11249002001</td>
			<td>For digestion of exocrine pancreas</td>
		</tr>
		<tr>
			<td>Curved surgical scissors</td>
			<td>Fisher-Scientific</td>
			<td>13-804-21</td>
			<td>For cutting open mouse abdomen</td>
		</tr>
		<tr>
			<td>Dissection microscope</td>
			<td>Olympus</td>
			<td>SZX16</td>
			<td>Used for identification of key anatomical structures to accurately deliver collagenase into pancreas</td>
		</tr>
		<tr>
			<td>Hank&#39;s Balanced Salt Solution 10x</td>
			<td>Corning</td>
			<td>20-023-CV</td>
			<td>Washing cells</td>
		</tr>
		<tr>
			<td>Histopaque-1077</td>
			<td>Sigma</td>
			<td>RNBF5100</td>
			<td>For gradient formation</td>
		</tr>
		<tr>
			<td>Light source</td>
			<td>Leeds</td>
			<td>LR92240</td>
			<td>Enhancing visibility of microscope</td>
		</tr>
		<tr>
			<td>RNaseZap</td>
			<td>Fisher-Scientific</td>
			<td>AM9780</td>
			<td>For removing RNase</td>
		</tr>
		<tr>
			<td>RPMI-1640 Media w/o L-Glutamine</td>
			<td>Corning</td>
			<td>15-040-CV</td>
			<td>Culturing Islets</td>
		</tr>
		<tr>
			<td>Schwartz micro serrefines (Microvascular clamp)</td>
			<td>Fine Science Tools</td>
			<td>18052-01</td>
			<td>Clamping common bile duct and hepatic artery</td>
		</tr>
		<tr>
			<td>Shaking waterbath</td>
			<td>Boekel/Grant</td>
			<td>8R0534008</td>
			<td>Important for mechanical digestion of exocrine tissue</td>
		</tr>
		<tr>
			<td>Small surgical scissors</td>
			<td>VWR</td>
			<td>82027-578</td>
			<td>Cuttitng tissue that atached to pancreas</td>
		</tr>
	</tbody>
</table>

a simple high efficiency protocol for pancreatic islet isolation from mice

Pancreatic islets, also called the Islets of Langerhans, are a cluster of endocrine cells which produces hormones for glucose regulation and other important biological functions. The islets primarily consist of five types of hormone-secreting cells: &#945; cells secrete glucagon, &#946; cells secrete insulin, &#948; cells secrete somatostatin, &#949; cells secrete ghrelin, and PP cells secrete pancreatic polypeptide. Sixty to 80% of the cells in the islets are &#946; cells, which are the most important cell population to study insulin secretion. Pancreatic islets are a crucial model system to study ex vivo insulin secretion. Acquiring high quality islets is of great importance for diabetes research. Most islet isolation procedures require technically difficult to access site of collagenase injection, harsh and complex digestion procedures, and multiple density gradient purification steps. This paper features a simple high yield mouse islet isolation method with detailed descriptions and realistic demonstrations, showing the following specific steps: 1) injection of collagenase P at the ampulla of Vater, a small area joining the pancreatic duct and the common bile duct, 2) enzymatic digestion and mechanical separation of the exocrine pancreas, and 3) a single gradient purification step. The advantages of this method are the injection of digestive enzyme using the more accessible ampulla of Vater, more complete digestion using combination of enzymatic and mechanical approaches, and a simpler single gradient purification step. This protocol produces approximately 250&#8212;350 islets per mouse; and islets are suitable for various ex vivo studies. Possible caveats of this procedure are potentially damaged islets due to enzymatic digestion and/or prolonged gradient incubation, all of which can be largely avoided by careful ad justification of incubation time.

Proper completion of this procedure requires some understanding of mouse anatomy in the abdominal cavity. This allows for proper identification of the ampulla of Vater and clamping of the common bile duct. The entire procedure normally takes 1&#8211;2 h. It is more efficient to isolate islets from 4&#8211;6 mice at the same time, so several samples can be centrifuged together. The time for islet-picking varies, depending on the number of islets and the efficiency of digestion; it may take roughly an hour to pick 250&#821...

Watch this Scientific Journal Video about A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice at JoVE.com

A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice

This islet isolation protocol described a novel route of collagenase injection to digest the exocrine tissue and a simplified gradient procedure to purify the islets from mice. It involves enzymatic digestion, gradient separation/purification, and islet hand-picking. Successful isolation can yield 250&#8211;350 high quality and fully functional islets per mouse.

Pancreatic islets, also called the Islets of Langerhans, are a cluster of endocrine cells which produces hormones for glucose regulation and other ...

This protocol requires the use of a single density gradient making it significantly less labor intensive and more cost effective compared to more complex conventional islet isolation methods. The main advantage of this protocol is that the enzyme is delivered directly to the pancreas resulting in an enhanced tissue digestion and increased islet yield. Begin by taping the limbs of the mouse in the supine position and spraying the body with 70%ethanol.Using coverglass forceps and curved surgical scissors, make an approximately three centimeter horizontal abdominal skin incision and pull open the skin to expose the abdominal wall. Make a three to four centimeter vertical incision on the abdominal peritoneum to fully expose the pancreas and place the mouse under a dissecting microscope. Push the liver lobe superiorly to expose the bile duct which appears as a pale pink tube and gently move the intestines from the right lumbar and iliac region to the right of the abdominal cavity to expose the bile duct and hepatic artery.Use Schwartz micro serrefines to carefully clamp the common bile duct as close to the liver as possible and identify the ampulla of Vater which is located at the duodenal papilla and formed by the union of the pancreatic duct and the common bile duct. Using micro Adson forceps to pull the common bile duct taught, insert a 30 gauge half-inch needle attached to a three milliliter syringe containing three milliliters of freshly prepared collagenase P solution into the ampulla of Vater pushing the needle into the duct parallel to the vessel for about a quarter of the length of the vessel. Once the needle is in place, stabilize the needle with micro Adson forceps and slowly and steadily inject three milliliters of collagenase P solution into the duct.The injection is considered successful if the head, neck, body, and tail regions of the pancreas are fully inflated. Proper entry into the ampulla and cannulation of the common bile duct are critical for a successful digestion harvest. Piercing the ductal walls reduces the efficacy of the isolation.Using curved and micro Adson forceps, carefully pull out the inflated pancreas starting at the spleen and continuing toward the stomach and along the duodenum. Then place the pancreas in a 50 milliliter digestion tube containing three milliliters of ice cold collagenase P solution. To harvest the islets, first use fine surgical scissors to chop the pancreas for three to five seconds before placing the tube in a 37 degree Celsius water bath at 100 to 120 rotations per minute for 12 to 13 minutes.At the end of the incubation, gently shake the tube for about 30 seconds to disrupt the tissue until the solution is homogenous as confirmed by fine sand-like pancreatic tissue particles. As soon as the tissue is digested, place the tube on ice and add 40 milliliters of ice cold stop solution to terminate the enzymatic reaction. After gently disrupting the pellet, spin down the digested tissue in a swinging bucket centrifuge followed by two centrifugations with 20 milliliters of fresh stop solution per wash.After the last wash, resuspend the pellet in 40 milliliters of ice cold HBSS for three additional washes, resuspending the pellet in five milliliters of room temperature density gradient solution after the last wash. Vortex the tube briefly at low speed until the solution is homogenized before adding another five milliliters of room temperature density gradient to the tube. Now use a 10 milliliter pipette to gently and slowly add 10 milliliters of room temperature HBSS to the tube in a drop-wise manner to allow the formation of a gradient and use a swinging bucket centrifuge to isolate the cell populations by density gradient separation.At the end of the centrifugation, use a 10 milliliter pipette pre-wet with cold HBSS to collect five to 10 milliliters of the islet layer between the density gradient and the HBSS. Transfer the islets into a new 50 milliliter tube containing 20 milliliters of fresh ice cold HBSS and collect the cells by centrifugation in a swinging bucket centrifuge. Carefully aspirate all but the last three milliliters of the supernatant without disturbing the pellet and wash the islets at least three more times with 20 milliliters of fresh HBSS per wash.After the last wash, replace the supernatant with four milliliters of 37 degree Celsius RMPI 1640 medium and gently swirl the tube to dislodge the pellet. Immediately pour the islets into a 100 millimeter Petri dish and wash the tube with five milliliters of fresh RPMI 1640 medium to collect any remaining islets pooling the wash with the other islets. Then use a dissection microscope and a 20 microliter pipette tip to pick healthy spherical or oblong golden brown islets with a smooth surface from the Petri dish for transfer into a new Petri dish containing 10 milliliters of complete RPMI 1640 medium.When all of the islets have been collected, place the islets in a sterile incubator at 37 degrees Celsius and 5%carbon dioxide in humidified air overnight. Good healthy islets appear to have a smooth round shape while bad damaged islets exhibit rough edges. Undigested exocrine tissue is translucent in appearance and demonstrates an irregular shape.A proper cannulation and distribution of the collagenase P enzyme can be confirmed by an inflation of the splenic portion of the pancreas. Overnight incubation in low glucose media can prime the islets for a glucose-stimulated insulin secretion assay at the following day allowing insight into the insulin secretory capacity of the islets.

a-simple-high-efficiency-protocol-for-pancreatic-islet-isolation-from

Research

JoVE Journal

Biology

Murine Pancreatic Islet Isolation

Neutrophil Isolation Protocol

Neutrophil polymorphonuclear granulocytes (PMN) are the most abundant leukocytes in humans and among the first cells to arrive on the site of inflammatory immune response. Due to their key role in inflammation, neutrophil functions such as locomotion, cytokine production, phagocytosis, and tumor cell combat are extensively studied. To characterize the specific functions of neutrophils, a clean, fast, and reliable method of separating them from other blood cells is desirable for in vitro studies, especially since neutrophils are short-lived and should be used within 2-4 hours of collection. Here, we demonstrate a standard density gradient separation method to isolate human neutrophils from whole blood using commercially available separation media that is a mixture of sodium metrizoate and Dextran 500. The procedure consists of layering whole blood over the density gradient medium, centrifugation, separation of neutrophil layer, and lysis of residual erythrocytes. Cells are then washed, counted, and resuspended in buffer to desired concentration. When performed correctly, this method has been shown to yield samples of >95% neutrophils with >95% viability.

Neutrophils are among the first cells to arrive on the site of inflammatory immune response, and their functions and mechanisms have been studied extensively in vitro. We demonstrate a standard density gradient separation method to isolate human neutrophils from whole blood using commercially available separation media.

Neutrophil polymorphonuclear granulocytes (PMN) are the most abundant leukocytes in humans and among the first cells to arrive on the site of inflammatory ...

Human Pancreatic Islet Isolation: Part I: Digestion and Collection of Pancreatic Tissue

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients 1, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet mass is important for successful islet transplantation. However, donor characteristic, organ procurement and preservation affect the isolation outcome 2. At University of Illinois at Chicago (UIC) we have developed a successful isolation protocol with an improved purification gradient 3. The program started in January 2004, and more than 300 isolations were performed up to November 2008. The pancreata were sent in cold preservation solutions (UW, University of Wisconsin or HTK, Histidine-Tryptophan Ketoglutarate) 4-7 to the Cell Isolation Laboratory at UIC for islet isolation. Pancreatic islets were isolated using the UIC method, which is a modified version of the method originally described by Ricordi et al 8. Briefly, after cleaning the pancreas from the surrounding tissue, it was perfused with enzyme solution (Serva Collagenase + Neutral Protease or Sigma V enzyme). The distended pancreas was then transferred to the Ricordi digestion chamber, connected to a modified, closed circulation tubing system, and warmed up to 37&deg;C. During the digestion, the chamber was shaken gently. Samples were taken continuously to monitor the digestion progress. Once free islets were detected under the microscope, the digestion was stopped by flushing cold (4&deg;C) RPMI dilution solution (Mediatech, Herndon, VA) into the circulation system to dilute the enzyme. After being collected and washed in M199 media supplemented with human albumin, the tissue was sampled for pre-purification count and incubated with UW solution before purification. Purification process will be described in Part II: Purification and Culture of Human Islets.

Achieving high quality and appropriate quantity of human islets is one of the prominent prerequisites for successful islet transplantation. In this video, we describe step by step the procedures for human pancreatic islet isolation (part I: digestion and collection of pancreatic tissue) using a modified automated method.

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of ...

Human Pancreatic Islet Isolation: Part II: Purification and Culture of Human Islets

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients 1, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet mass is important for successful islet transplantation. However, donor characteristics, organ procurement and preservation affect the isolation outcome 2. At University of Illinois at Chicago (UIC) we developed a successful isolation protocol with an improved purification gradient 3. The program started in January 2004 and more than 300 isolations were performed up to November 2008. The pancreata were sent in cold preservation solutions (UW, University of Wisconsin or HTK, Histidine-Tryptophan Ketoglutarate) 4-7 to the Cell Isolation Laboratory at UIC for islet isolation. Pancreatic islets were isolated using the UIC method, which is a modified version of the method originally described by Ricordi et al 8. As described in Part I: Digestion and Collection of Pancreatic Tissue, human pancreas was trimmed, cannulated, perfused, and digested. After collection and at least 30 minutes of incubation in UW solution, the tissue was loaded in the cell separator (COBE 2991, Cobe, Lakewood, CO) for purification 3. Following purification, islet yield (expressed as islet equivalents, IEQ), tissue volume, and purity was determined according to standard methods 9. Isolated islets were cultured in CMRL-1066 media (Mediatech, Herndon, VA), supplemented with 1.5% human albumin, 0.1% insulin-transferrin-selenium (ITS), 1 ml of Ciprofloxacin, 5 ml o f 1M HEPES, and 14.5 ml of 7.5% Sodium Bicarbonate in T175 flasks at 37&deg;C overnight culture before islets were transplanted or used for research.

Achieving high quality and appropriate quantity of human islets is one of the prominent prerequisites for successful islet transplantation. In this video, we describe step by step the procedures for human pancreatic islet isolation (part II: purification and culture of human islets) using a modified automated method.

Isolation of Stem Cells from Human Pancreatic Cancer Xenografts

Cancer stem cells (CSCs) have been identified in a growing number of malignancies and are functionally defined by their ability to undergo self-renewal and produce differentiated progeny1. These properties allow CSCs to recapitulate the original tumor when injected into immunocompromised mice. CSCs within an epithelial malignancy were first described in breast cancer and found to display specific cell surface antigen expression (CD44+CD24low/-)2. Since then, CSCs have been identified in an increasing number of other human malignancies using CD44 and CD24 as well as a number of other surface antigens. Physiologic properties, including aldehyde dehydrogenase (ALDH) activity, have also been used to isolate CSCs from malignant tissues3-5.
Recently, we and others identified CSCs from pancreatic adenocarcinoma based on
ALDH activity and the expression of the cell surface antigens CD44 and CD24, and CD1336-8. These highly tumorigenic populations may or may not be overlapping and display other functions. We found that ALDH+ and CD44+CD24+ pancreatic CSCs are similarly tumorigenic, but ALDH+ cells are relatively more invasive8. In this protocol we describe a method to isolate viable pancreatic CSCs from low-passage human
xenografts9. Xenografted tumors are harvested from mice and made into a single-cell suspension. Tissue debris and dead cells are separated from live cells and then stained using antibodies against CD44 and CD24 and using the ALDEFLUOR reagent,
a fluorescent substrate of ALDH10. CSCs are then isolated by fluorescence activated cell sorting. Isolated CSCs can then be used for analytical or functional assays requiring viable cells.

Cancer stem cells (CSCs) have been identified in a number of malignancies. In this protocol we describe a flow cytometric method utilizing aldehyde dehydrogenase activity and CD44 and CD24 expression to isolate CSCs from human pancreatic adenocarcinoma xenografts. These viable cells can then be used in functional and analytical studies.

Cancer stem cells (CSCs) have been identified in a growing number of malignancies and are functionally defined by their ability to undergo self-renewal ...

Mouse Islet of Langerhans Isolation using a Combination of Purified Collagenase and Neutral Protease

The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines to the study of isolated rodent islets. Primary islets offer the distinct advantage that they more faithfully reflect the biology of intracellular signaling pathways and secretory responses. Whereas the method of islet isolation using tissue dissociating enzyme (TDE) preparations has been well established in many laboratories1-4, variations in the consistency of islet yield and quality from any given rodent strain limit the extent and feasibility of primary islet studies. These variations often occur as a result of the crude partially purified TDEs used in the islet isolation procedure; TDEs frequently exhibit lot-to-lot variations in activity and often require adjustments to the dose of enzyme used. A small number of reports have used purified TDEs for rodent cell isolations5, 6, but the practice is not widespread despite the routine use and advantages of purified TDEs for human islet isolations. In collaboration with VitaCyte, LLC (Indianapolis, IN), we developed a modified mouse islet isolation protocol based on that described by Gotoh7, 8, in which the TDEs are perfused directly into the pancreatic duct of mice, followed by crude tissue fractionation through a Histopaque gradient9, and isolation of purified islets. A significant difference in our protocol is the use of purified collagenase (CIzyme MA) and neutral protease (CIzyme BP) combination. The collagenase was characterized by the use of a6 fluorescence collagen degrading activity (CDA) assay that utilized fluorescently labeled soluble calf skin fibrils as substrate6. This substrate is more predictive of the kinetics of collagen degradation in the tissue matrix because it relies on native collagen as the substrate. The protease was characterized with a sensitive fluorescent kinetic assay10. Utilizing these improved assays along with more traditional biochemical analysis enable the TDE to be manufactured more consistently, leading to improved performance consistency between lots. The protocol described in here was optimized for maximal islet yield and optimal islet morphology using C57BL/6 mice. During the development of this protocol, several combinations of collagenase and neutral proteases were evaluated at different concentrations, and the final ratio of collagenase:neutral protease of 35:10 represents enzyme performance comparable to Sigma Type XI. Because significant variability in average islet yields from different strains of rats and mice have been reported, additional modifications of the TDE composition should be made to improve the yield and quality of islets recovered from different species and strains.

A detailed description of mouse islet isolation is described using the technique of in situ pancreatic ductal cannulation and perfusion of a combination of purified collagenase and neutral protease.

The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines ...

A Simple Protocol for Extracting Hemocytes from Wild Caterpillars

Insect hemocytes (equivalent to mammalian white blood cells) play an important role in several physiological processes throughout an insect's life cycle 1. In larval stages of insects belonging to the orders of Lepidoptera (moths and butterflies) and Diptera (true flies), hemocytes are formed from the lymph gland (a specialized hematopoietic organ) or embryonic cells and can be carried through to the adult stage. Embryonic hemocytes are involved in cell migration during development and chemotaxis regulation during inflammation. They also take part in cell apoptosis and are essential for embryogenesis 2. Hemocytes mediate the cellular arm of the insect innate immune response that includes several functions, such as cell spreading, cell aggregation, formation of nodules, phagocytosis and encapsulation of foreign invaders 3. They are also responsible for orchestrating specific insect humoral defenses during infection, such as the production of antimicrobial peptides and other effector molecules 4, 5. Hemocyte morphology and function have mainly been studied in genetic or physiological insect models, including the fruit fly, Drosophila melanogaster 6, 7, the mosquitoes Aedes aegypti and Anopheles gambiae 8, 9 and the tobacco hornworm, Manduca sexta 10, 11. However, little information currently exists about the diversity, classification, morphology and function of hemocytes in non-model insect species, especially those collected from the wild 12.
Here we describe a simple and efficient protocol for extracting hemocytes from wild caterpillars. We use penultimate instar Lithacodes fasciola (yellow-shouldered slug moth) (Figure 1) and Euclea delphinii (spiny oak slug) caterpillars (Lepidoptera: Limacodidae) and show that sufficient volumes of hemolymph (insect blood) can be isolated and hemocyte numbers counted from individual larvae. This method can be used to efficiently study hemocyte types in these species as well as in other related lepidopteran caterpillars harvested from the field, or it can be readily combined with immunological assays designed to investigate hemocyte function following infection with microbial or parasitic organisms 13.

Insect hemocytes carry out many important functions, both immune and non-immune, throughout all stages of insect development. Our present knowledge of hemocyte types and function comes from studies on insect genetic models. Here, we present a method for extracting, quantifying and visualizing hemocytes from wild caterpillars.

Insect hemocytes (equivalent to mammalian white blood cells) play an important role in several physiological processes throughout an insect's life cycle ...

A Method for Mouse Pancreatic Islet Isolation and Intracellular cAMP Determination

Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing prevalence of diabetes, both immune-mediated type 1 and obesity-linked type 2, studies aimed at delineating diabetes pathophysiology and therapeutic mechanisms are of critical importance. The &#946;-cells of the pancreatic islets of Langerhans are responsible for appropriately secreting insulin in response to elevated blood glucose concentrations. In addition to glucose and other nutrients, the &#946;-cells are also stimulated by specific hormones, termed incretins, which are secreted from the gut in response to a meal and act on &#946;-cell receptors that increase the production of intracellular cyclic adenosine monophosphate (cAMP). Decreased &#946;-cell function, mass, and incretin responsiveness are well-understood to contribute to the pathophysiology of type 2 diabetes, and are also being increasingly linked with type 1 diabetes. The present mouse islet isolation and cAMP determination protocol can be a tool to help delineate mechanisms promoting disease progression and therapeutic interventions, particularly those that are mediated by the incretin receptors or related receptors that act through modulation of intracellular cAMP production. While only cAMP measurements will be described, the described islet isolation protocol creates a clean preparation that also allows for many other downstream applications, including glucose stimulated insulin secretion, [3H]-thymidine incorporation, protein abundance, and mRNA expression.

Assaying in vitro &#946;-cell function using isolated mouse islets of Langerhans is an important component in the study of diabetes pathophysiology and therapeutics. While many&#160;downstream applications are available, this protocol specifically describes the measurement of intracellular cyclic adenosine monophosphate (cAMP) as an essential parameter determining &#946;-cell function.

Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing ...

Pancreatic Islet Embedding for Paraffin Sections

Experiments using isolated pancreatic islets are important for diabetes research, but islets are expensive and of limited abundance. Islets contain a mixed cell population in a structured architecture that impacts function, and human islets are widely variable in cell type composition. Current frequently used methods to study cultured islets include molecular studies performed on whole islets, lumping disparate islet cell types together, or microscopy or molecular studies on dispersed islet cells, disrupting islet architecture. For in vivo islet studies, paraffin-embedded pancreas sectioning is a powerful technique to assess cell-specific outcomes in the native pancreatic environment. Studying post-culture islets by paraffin sectioning would offer several advantages: detection of multiple outcomes on the same islets (potentially even the exact-same islets, using serial sections), cell-type-specific measurements, and maintaining native islet cell-cell and cell-substratum interactions both during experimental exposure and for analysis. However, existing techniques for embedding isolated islets post-culture are inefficient, time consuming, prone to loss of material, and generally produce sections with inadequate islet numbers to be useful for quantifying outcomes. Clinical pathology laboratory cell block preparation facilities are inaccessible and impractical for basic research laboratories. We have developed an improved, simplified bench-top method that generates sections with robust yield and distribution of islets. Fixed islets are resuspended in warm histological agarose gel and pipetted into a flat disc on a standard glass slide, such that the islets are distributed in a plane. After standard dehydration and embedding, multiple (10+) 4 - 5 &#181;m sections can be cut from the same islet block. Using this method, histological&#160;and immunofluorescent analyses can be performed on mouse, rat, and human islets. This is an effective, inexpensive, time-saving approach to assess cell-type-specific, intact-architecture outcomes from cultured islets.

Ex vivo pancreatic islet studies are important for diabetes research. Existing techniques to study cultured islets in their native 3-dimensional architecture are time consuming, inefficient, and infrequently used. This work describes a new, simple, and efficient method for generating high-quality paraffin sections of whole cultured islets.

Experiments using isolated pancreatic islets are important for diabetes research, but islets are expensive and of limited abundance. Islets contain a ...

Imaging Calcium Dynamics in Subpopulations of Mouse Pancreatic Islet Cells

Pancreatic islet hormones regulate blood glucose homeostasis. Changes in blood glucose induce oscillations of cytosolic calcium in pancreatic islet cells that trigger secretion of three main hormones: insulin (from &#946;-cells), glucagon (&#945;-cells) and somatostatin (&#948;-cells). &#946;-Cells, which make up the majority of islet cells and are electrically coupled to each other, respond to the glucose stimulus as one single entity. The excitability of the minor subpopulations, &#945;-cells and &#948;-cells (making up around 20% (30%) and 4% (10%) of the total rodent1 (human2) islet cell numbers, respectively) is less predictable and is therefore of special interest.
Calcium sensors are delivered into the peripheral layer of cells within the isolated islet. The islet or a group of islets is then immobilized and imaged using a fluorescence microscope. The choice of the imaging mode is between higher throughput (wide-field) and better spatial resolution (confocal). Conventionally, laser scanning confocal microscopy is used for imaging tissue, as it provides the best separation of the signal between the neighboring cells. A wide-field system can be utilized too, if the contaminating signal from the dominating population of &#946;-cells is minimized.
Once calcium dynamics in response to specific stimuli have been recorded, data are expressed in numerical form as fluorescence intensity vs. time, normalized to the initial fluorescence and baseline-corrected, to remove the effects linked to bleaching of the fluorophore. Changes in the spike frequency or partial area under the curve (pAUC) are computed vs. time, to quantify the observed effects. pAUC is more sensitive and quite robust whereas spiking frequency provides more information on the mechanism of calcium increase.
Minor cell subpopulations can be identified using functional responses to marker compounds, such as adrenaline and ghrelin, that induce changes in cytosolic calcium in a specific populations of islet cells.

Here, we present a protocol for imaging and quantifying calcium dynamics in heterogeneous cell populations, such as pancreatic islet cells. Fluorescent reporters are delivered into the peripheral layer of cells within the islet, which is then immobilized and imaged, and per-cell analysis of the dynamics of fluorescence intensity is performed.

Pancreatic islet hormones regulate blood glucose homeostasis. Changes in blood glucose induce oscillations of cytosolic calcium in pancreatic islet cells ...