This work was supported by grants from National Key R&#38;D Program of China (2017YFC1103704)Special Funds for the Construction of High Level Hospitals in Guangdong Province (2019), Sanming Project of Medicine in Shenzhen (SZSM201412020), Fund for High Level Medical Discipline Construction of Shenzhen (2016031638), Shenzhen Foundation of Science and Technology (JCJY20160229204849975, GJHZ20170314171357556), Shenzhen Foundation of Health and Family Planning Commission (SZXJ2017021SZXJ2018059), Medical Scientific Research Foundation of Guangdong Province of China (A2019218), China Postdoctoral Science Foundation (2018M633218).

All procedures in this protocol followed the principles of animal welfare of the Ethics Review Committee of Shenzhen Second People&#39;s Hospital. Islet graft recipients and donors were 8- to 10-week-old C57BL/6 male mice purchased from the Medical Animal Center of Guangdong Province. The procedure of the harvesting, isolation, culture, or administration of the harvested cells were carried out in aseptic conditions.
1. Islet preparation
<ol>
	<li>Prepare a collagenase Type V working solution. Weigh collagenase Type V and dissolve with D-Hank&#39;s buffer to a final concentration of 1 mg/mL, filter using a 0.22 &#956;m syringe-driven filter unit and a 60 mL syringe and precool in ice. A volume of 5 mL for each donor recipient is required.</li>
	<li>Euthanize a 10-week-old C57BL/6 male mouse (23 &#177; 2 g) by cervical dislocation and spray the external part of the mouse with 75% ethanol for a few seconds. Meanwhile, fill a 5 mL syringe with collagenase solution and change the syringe needle with a bending blunt-pointed perfusion needle (32 G).</li>
	<li>Put the donor mouse in the supine position on an ice bag under the dissecting scope, cut a transverse opening using straight pointed ophthalmic scissors in the skin of the pubic area, and completely incise the skin towards the head. Then completely open the abdomen via a V-incision from the pubic region to the xiphoid process.</li>
	<li>Expose the gall bladder and the entire length of the common bile duct by repositioning the liver. Then clamp the duodenal opening of the common bile duct with a vascular clamp and cut a small opening in the gallbladder. 
	NOTE: Optimal needle placement is important to prevent backflow into the liver and gallbladder.</li>
	<li>Cannulate the common bile duct from the gall bladder opening using the perfusion needle in step 1.2, then inject ~2 mL of collagenase solution into the pancreas. After that, separate the perfused pancreas from the intestines, stomach, and spleen using two pairs of noninvasive microtweezers, and put it into a 50 mL conical tube on ice. 
	NOTE: Repeat the process for all donor mice. Three consecutively perfused pancreases (no more than 40 min apart) can be combined into a 50 mL conical tube prefilled with 3 mL of collagenase solution for each pancreas.</li>
	<li>Add 100 &#956;L DNase I (10 mg/mL) per pancreas into the 50 mL conical tubes, and digest the pancreases in a water bath at 37 &#176;C by shaking the conical tubes for 3&#8211;5 min. 
	NOTE: Shake the tubes vigorously 40x in 10 s intervals to disassociate the tissue prior to digestion in the water bath, and then moderately shake the tubes during digestion.</li>
	<li>Add stop solution (2.5 mg/mL BSA-HBSS solution) up to a final volume of 50 mL to block the digestion, and pulse centrifuge the tubes to a speed of 750 x g at 4 &#176;C and quickly stop.</li>
	<li>Pour off the supernatant and wash the pellets 2x by gently resuspending in 15&#8211;25 mL of BSA-HBSS. Pulse centrifuge the tube with the same speed conditions as outlined in step 1.7 for 1 min.</li>
	<li>Pour off the supernatant and pool the pellets of the three conical tubes into a 50 mL conical tube. Resuspend the pellets in a total volume of 10 mL of histopaque-1119. Mix homogeneously, and sequentially add 5 mL of histopaque-1077 and 5 mL of HBSS by pipetting slowly along the side of the tube.</li>
	<li>Spin the samples in the centrifuge at 750 x g at 4 &#176;C for 10 min without brakes.</li>
	<li>Aspirate the islets from the HBSS/histopaque-1077 interface into a 50 mL conical tube using a disposable 5 mL Pasteur pipette, add BSA-HBSS to a final volume of 50 mL, and pulse centrifuge at 750 x g at 4 &#176;C.</li>
	<li>Pour off the supernatant and wash the islets using 30 mL of BSA-HBSS. Centrifuge for 1 min at 750 x g at 4 &#176;C.</li>
	<li>Resuspend the islets using 30 mL of culture medium (10% FBS-1%P/S-CMRL-1066) per tube and pour in a 10 cm diameter light-tight culture dish. Under a stereomicroscope, using 200 &#956;L gel-loading pipet tips, handpick the islets from the solution based on their morphology (i.e., spheroidal, white). Put into an untreated cell culture dish with 10 mL of culture medium. 
	NOTE: A second handpicking can be carried out if the purity of first-purified islets is not optimal after the first picking.</li>
	<li>Check the purity of the handpicked islets by dithizone staining under a light microscope and detect the viability of islets by fluorescein diacetate (FDA)-propidium iodide (PI) staining under a fluorescent microscope.</li>
	<li>Culture the isolated islets in culture medium (as in step 1.13) in an incubator at 37 &#176;C, 95% air-5% CO2 before transplantation.</li>
</ol>
2. ISWAT islet transplantation
<ol>
	<li>Induce diabetes in the 8-week-old male C57BL/6 mice (22 &#177; 2 g) by a single injection of streptozotocin (STZ). On day -4, fast the mice for ~4&#8211;6 h, then prepare a 2% STZ solution using 0.1 M citrate buffer (pH 4.4). Weigh, resuspend in buffer, and inject the mice intraperitoneally at a dose of 180 mg/kg. 
	NOTE: STZ solution needs to be freshly prepared before use and covered with aluminum foil due to its light sensitivity. It should be used immediately, because it will lose activity within 15&#8211;20 min.</li>
	<li>Puncture the caudal veins of the STZ-injected mice to collect some blood at around 10 AM of day -1 and day 0 and measure the non-fasting blood glucose level using a test strip and a basic blood glucose monitoring instrument. The mice will be used as islet transplantation recipients if the blood glucose levels of the 2 consecutive test days are both at least 20 mmol/L.</li>
	<li>On day 0, weigh and mark all the recipient mice. Anesthetize each recipient by injecting 60 mg/kg pentobarbital sodium intraperitoneally. 
	NOTE: Administer a toe pinch to check the depth of anesthesia. If the recipient mouse has no withdrawal reflex, the level of anesthesia is enough for surgery. If not, administer an additional 10 mg/kg pentobarbital sodium. The pentobarbital sodium used was diluted in sterile physiologic saline at the concentration of 2% (m/v).</li>
	<li>Take the hydrogel out from a -20 &#176;C freezer and keep it on ice to allow thawing. The hydrogel is liquid at 4&#8211;10 &#176;C and will solidify at a higher temperature.</li>
	<li>Pick ~450&#8211;500 islet equivalents (IEQ) for each recipient into a sterile 1.5 mL centrifuge tube under the stereomicroscope (as in step 1.13) with 200 &#181;L of culture medium and keep on ice until ready for transplantation.</li>
	<li>Swab the left inguinal area of the recipient using 75% ethanol. Place it in the supine position and fix the four limbs using surgical tape. Shave off the hair around the surgical site with electrical clippers and swab the area with Iodophor.</li>
	<li>Make a vertical skin incision in this area using the ophthalmic scissors and noninvasive microtweezers, identify the inferior epigastric artery and vein in the ISWAT, and create a small pocket above the vessels.</li>
	<li>Spin the islets tube for 30 s at 200 x g and remove the supernatant as much as possible. Aspirate 20 &#181;L of completely thawed hydrogel and load it into the tube with the islets. Resuspend the islets gently, avoiding bubbles.</li>
	<li>Deliver the entire islet-hydrogel mixture in the tube into the pocket (step 2.7) of the recipient with a 200 &#181;L pipette tip. 
	NOTE: This process requires two technicians, one for picking up the edges of the pocket using noninvasive microtweezers, and the other for delivering the islet mixture into the pocket.</li>
	<li>Add 20 &#181;L of cephalosporin (~5&#8211;10 mg) into the transplantation site after the islets-hydrogel mixture is completely solidified, then use a 5-0 surgical suture to close the muscle and skin with the continuous suture method. 
	NOTE: The hydrogel needs about 3 min to solidify due to the body temperature.</li>
	<li>Place the recipient into a clean cage and keep warm using a thermal pad. Keep monitoring until the recipient fully recovers and starts to move autonomously. Then administer 0.03 mg/ml Buprenorphine with sterile physiological saline intraperitoneally, according to 0.1 mg/Kg dose.</li>
	<li>Repeat steps 2.3&#8211;2.11 for each recipient mouse.</li>
	<li>Measure the non-fasting blood glucose levels of the recipient mice (as in step 2.2) 3&#8211;4x a week for the first month, and 1x a week thereafter.</li>
	<li>At the end of the follow-up (100 days after transplantation), under anesthesia (carried out as in step 2.3) excise the ISWAT bearing the graft from the recipients following the sterile steps described in step 2.6. Fix the tissue in formalin and paraformaldehyde according to the histological protocols for hematoxylin and eosin (H&#38;E) staining and immunofluorescence of insulin and glucagon.</li>
	<li>Add cephalosporin and close the incision of the recipients as in step 2.10, then prepare for recovery as in step 2.11.</li>
</ol>

<ol>
	<li>Cho, N. H., 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=IDF+Diabetes+Atlas:+Global+estimates+of+diabetes+prevalence+for+2017+and+projections+for+2045.">IDF Diabetes Atlas: Global estimates of diabetes prevalence for 2017 and projections for 2045.</a> Diabetes Research and Clinical Practice. 138, 271-281 (2018).</li><li>Shapiro, A. 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=Islet+transplantation+in+seven+patients+with+type+1+diabetes+mellitus+using+a+glucocorticoid-free+immunosuppressive+regimen.">Islet transplantation in seven patients with type 1 diabetes mellitus using a glucocorticoid-free immunosuppressive regimen.</a> New England Journal of Medicine. 343 (4), 230-238 (2000).</li><li>McCall, M., Shapiro, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Update+on+islet+transplantation.">Update on islet transplantation.</a> Cold Spring Harbor Perspectives in Medicine. 2 (7), 007823 (2012).</li><li>Pathak, V., Pathak, N. M., O'Neill, C. L., Guduric-Fuchs, J., Medina, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Therapies+for+Type+1+Diabetes:+Current+Scenario+and+Future+Perspectives.">Therapies for Type 1 Diabetes: Current Scenario and Future Perspectives.</a> Clinical Medicine Insights: Endocrinology and Diabetes. 12, 1179551419844521 (2019).</li><li>Bottino, R., Knoll, M. F., Knoll, C. A., Bertera, S., Trucco, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Future+of+Islet+Transplantation+Is+Now.">The Future of Islet Transplantation Is Now.</a> Frontiers in Medicine (Lausanne). 5, 202 (2018).</li><li>Stokes, R. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transplantation+sites+for+human+and+murine+islets.">Transplantation sites for human and murine islets.</a> Diabetologia. 60 (10), 1961-1971 (2017).</li><li>van der Windt, D. J., Echeverri, G. J., Ijzermans, J. N., Cooper, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+choice+of+anatomical+site+for+islet+transplantation.">The choice of anatomical site for islet transplantation.</a> Cell Transplantation. 17 (9), 1005-1014 (2008).</li><li>Addison, P., Fatakhova, K., Rodriguez Rilo, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Considerations+for+an+Alternative+Site+of+Islet+Cell+Transplantation.">Considerations for an Alternative Site of Islet Cell Transplantation.</a> Journal of Diabetes Science and Technology. , (2019).</li><li>Pepper, A. R., Bruni, A., Shapiro, A. M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+islet+transplantation:+is+the+future+finally+now.">Clinical islet transplantation: is the future finally now.</a> Current Opinion in Organ Transplantation. 23 (4), 428-439 (2018).</li><li>Bellin, M. 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=Similar+islet+function+in+islet+allotransplant+and+autotransplant+recipients,+despite+lower+islet+mass+in+autotransplants.">Similar islet function in islet allotransplant and autotransplant recipients, despite lower islet mass in autotransplants.</a> Transplantation. 91 (3), 367-372 (2011).</li><li>Bruni, A., Gala-Lopez, B., Pepper, A. R., Abualhassan, N. S., Shapiro, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Islet+cell+transplantation+for+the+treatment+of+type+1+diabetes:+recent+advances+and+future+challenges.">Islet cell transplantation for the treatment of type 1 diabetes: recent advances and future challenges.</a> Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy. 7, 211-223 (2014).</li><li>Smood, B., Bottino, R., Hara, H., Cooper, D. K. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Is+the+renal+subcapsular+space+the+preferred+site+for+clinical+porcine+islet+xenotransplantation?+Review+article.">Is the renal subcapsular space the preferred site for clinical porcine islet xenotransplantation? Review article.</a> International Journal of Surgery and Medicine. 69, 100-107 (2019).</li><li>Luan, N. M., Iwata, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+allogeneic+islet+graft+survival+in+prevascularized+subcutaneous+sites+without+immunosuppressive+treatment.">Long-term allogeneic islet graft survival in prevascularized subcutaneous sites without immunosuppressive treatment.</a> American Journal of Transplantation. 14 (7), 1533-1542 (2014).</li><li>Yasunami, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Subcutaneous+Site+of+Islet+Transplantation+Superior+to+the+Liver.">A Novel Subcutaneous Site of Islet Transplantation Superior to the Liver.</a> Transplantation. 102 (6), 945-952 (2018).</li><li>Rajab, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Islet+transplantation:+alternative+sites.">Islet transplantation: alternative sites.</a> Current Diabetes Reports. 10 (5), 332-337 (2010).</li><li>Ekser, B., Vagefi, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Search+for+the+best+site+in+islet+xenotransplantation.">Search for the best site in islet xenotransplantation.</a> International Journal of Surgery and Medicine. 70, 106-107 (2019).</li><li>Lu, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Method+for+Islet+Transplantation+to+the+Omentum+in+Mouse.">A Method for Islet Transplantation to the Omentum in Mouse.</a> Journal of Visualized Experiments. (143), e57160 (2019).</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. (88), e50374 (2014).</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> Journal of Visualized Experiments. (50), e2096 (2011).</li><li>Khatri, R., Hussmann, B., Rawat, D., Gurol, A. O., Linn, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraportal+Transplantation+of+Pancreatic+Islets+in+Mouse+Model.">Intraportal Transplantation of Pancreatic Islets in Mouse Model.</a> Journal of Visualized Experiments. (135), e57559 (2018).</li><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></ol>

The authors report no conflicts of interest.

&#160; &#160;

Pancreas islet transplantation is a promising therapy to treat T1DM. The effect of this therapy is affected by many factors and choosing an optimal site for islet implantation is extremely important. The ideal anatomical site for islet transplantation should have the following characteristics: accessibility for simple transplantation, biopsy, and graft retrieval procedures; reduced complications; high success rate of blood glucose control; and long-term survival of the islet grafts15,<s...

The worldwide incidence and prevalence of type 1 diabetes mellitus (T1DM) are quickly rising, according to the statistical data of the International Diabetes Federation (IDF)1. Islet transplantation is one of the most promising approaches for treating T1DM4. Since the great breakthrough made in clinical islet transplantation using the Edmonton protocol2 was reported, functioning islet graft survival in T1DM recipients after 5 years now reaches about 50%3.
In the past, several transplantation sites, such as the liver, kidney capsule, spleen, intramuscular region, subcutaneous space, bone marrow, and omental pouch were explored for experimental islet transplantation5,6,7. Some of the above sites have been tested in clinical settings8. Although islet transplantation into the liver remains the most widely used method in clinical application at present9, there are several important problems to address when using this site. For instance, how to reduce early loss of the transplanted islets caused by the instant blood mediated inflammatory reaction (IBMIR) and poor oxygenation supply10,11 and how to retrieve the islet grafts if necessary, because they diffusely localize in the liver. The renal capsule may be an ideal site for rodent recipients. However, the tight kidney capsule limits the transplantation of sufficient allogeneic islets in humans, although it may be a better fit for islet xenotransplantation due to the highly purified porcine islet preparations used clinically5,12. Therefore, the search for a more suitable site for islet transplantation is in progress.
The subcutaneous space may be used as a clinically applicable site for islet transplantation due to its accessibility. However, the efficiency of islet transplantation into the subcutaneous space is extremely low, thus requiring a relatively large number of islets to reverse hyperglycemia13. Recently, a Japanese research team found the ISWAT, a novel subcutaneous site superior for islet transplantation in a murine model when compared to the liver14. The ISWAT contains the epigastric artery and vein, so the rich blood supply may ensure islet graft revascularization. In this manuscript, we propose an easy implantation method using a basement membrane matrix hydrogel to fix syngeneic murine islets in the ISWAT. This protocol proves effective for islet transplantation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.22 &#956;m Syringe-driven Filter Unit</td>
			<td>Merck Millipore</td>
			<td>SLHV033RB</td>
			<td></td>
		</tr>
		<tr>
			<td>1.5 mL centrifuge tube</td>
			<td>Axygen</td>
			<td>MCT-150-C</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL Pasteur pipette</td>
			<td>JingAn Biological, China</td>
			<td>J00085</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL syringe</td>
			<td>Szboon, China</td>
			<td>20170829</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL conical tube</td>
			<td>Corning</td>
			<td>430829</td>
			<td></td>
		</tr>
		<tr>
			<td>5-0 surgical suture</td>
			<td>sh-Jinhuan, China</td>
			<td>CR537</td>
			<td></td>
		</tr>
		<tr>
			<td>60 mL syringe</td>
			<td>Szboon, China</td>
			<td>20170623</td>
			<td></td>
		</tr>
		<tr>
			<td>75% Ethanol</td>
			<td>LIRCON, China</td>
			<td>9180527</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa Fluor 488 donkey anti-mouse IgG(H+L)</td>
			<td>Invitrogen</td>
			<td>A21202</td>
			<td>Dilution (1:200)</td>
		</tr>
		<tr>
			<td>anti-mouse Glucagon antibody</td>
			<td>Abcam</td>
			<td>ab10988</td>
			<td>Dilution (1:100)</td>
		</tr>
		<tr>
			<td>anti-mouse insulin antibody</td>
			<td>Cell Signaling Technology</td>
			<td>3014s</td>
			<td>Dilution (1:100)</td>
		</tr>
		<tr>
			<td>blunt-pointed perfusion needle</td>
			<td>Oloey, China</td>
			<td>005</td>
			<td>32G, yellow</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Meilune, China</td>
			<td>MB4219</td>
			<td></td>
		</tr>
		<tr>
			<td>C57BL/6 Mice</td>
			<td>Medical Animal Center of Guangdong Province</td>
			<td></td>
			<td>8~10 weeks</td>
		</tr>
		<tr>
			<td>cell culture dish</td>
			<td>BIOFIL, China</td>
			<td>TCD000100</td>
			<td>General,Non-treated,87.8 mm diameter</td>
		</tr>
		<tr>
			<td>centrifuge</td>
			<td>Thermo Scientific</td>
			<td>ST16R</td>
			<td></td>
		</tr>
		<tr>
			<td>cephalosporin</td>
			<td>Lukang medical, China</td>
			<td>150303</td>
			<td></td>
		</tr>
		<tr>
			<td>CMRL-1066</td>
			<td>Sigma-Aldrich</td>
			<td>C0422</td>
			<td></td>
		</tr>
		<tr>
			<td>Codos Pet Clipper</td>
			<td>Szcodos, China</td>
			<td>CP-8000</td>
			<td></td>
		</tr>
		<tr>
			<td>collagenase Type V</td>
			<td>Sigma</td>
			<td>C9262</td>
			<td></td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Thermo Fisher</td>
			<td>D1306</td>
			<td></td>
		</tr>
		<tr>
			<td>D-hank&#39;s buffer</td>
			<td>Coolaber, China</td>
			<td>PM5140-10</td>
			<td></td>
		</tr>
		<tr>
			<td>dithizone</td>
			<td>Sigma-Aldrich</td>
			<td>D5130</td>
			<td></td>
		</tr>
		<tr>
			<td>Dnase I</td>
			<td>Sigma-Aldrich</td>
			<td>D4263</td>
			<td></td>
		</tr>
		<tr>
			<td>Eosin staining media</td>
			<td>Beyotime Biotech, China</td>
			<td>C0109</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>GE Healthcare Life Sciences</td>
			<td>SH30084</td>
			<td></td>
		</tr>
		<tr>
			<td>fluorescein diacetate (FDA)</td>
			<td>Thermo Fisher</td>
			<td>F1303</td>
			<td></td>
		</tr>
		<tr>
			<td>fluorescent microscope</td>
			<td>Leica</td>
			<td>DMIL</td>
			<td></td>
		</tr>
		<tr>
			<td>gel-loading pipet tips</td>
			<td>Corning</td>
			<td>CLS4884</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>Coolaber, China</td>
			<td>PM5150-10</td>
			<td></td>
		</tr>
		<tr>
			<td>hematoxylin staining media</td>
			<td>Cell Signaling Technology</td>
			<td>14166S</td>
			<td></td>
		</tr>
		<tr>
			<td>HISTOPAQUE-1077</td>
			<td>Sigma-Aldrich</td>
			<td>RNBG0522</td>
			<td></td>
		</tr>
		<tr>
			<td>HISTOPAQUE-1119</td>
			<td>Sigma-Aldrich</td>
			<td>RNBG0536</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogel</td>
			<td>BD Biosciences</td>
			<td>356234</td>
			<td>Basement Membrane Matrix</td>
		</tr>
		<tr>
			<td>Iodophor</td>
			<td>LIRCON, China</td>
			<td>5190313</td>
			<td></td>
		</tr>
		<tr>
			<td>light-tight culture dish</td>
			<td>DVS, China</td>
			<td>AN-5058548</td>
			<td>self-made, glass dish sprayed with black paint</td>
		</tr>
		<tr>
			<td>Medical Adhesive Tape</td>
			<td>Cofoe, China</td>
			<td>K12001</td>
			<td></td>
		</tr>
		<tr>
			<td>non-invasive microtweezers</td>
			<td>RWD Life Science</td>
			<td>F11033-11 and F12016-15</td>
			<td></td>
		</tr>
		<tr>
			<td>One Touch ultraeasy Basic blood glucose monitoring system</td>
			<td>Johnson &#38; Johnson</td>
			<td>33391713</td>
			<td></td>
		</tr>
		<tr>
			<td>ophthalmic scissors</td>
			<td>RWD Life Science</td>
			<td>S12012-12 and S11001-08</td>
			<td></td>
		</tr>
		<tr>
			<td>P/S (penicillin / streptomycin)</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>pentobarbital sodium</td>
			<td>Sigma-Aldrich</td>
			<td>P-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Propidium iodide</td>
			<td>Sigma-Aldrich</td>
			<td>P4864</td>
			<td></td>
		</tr>
		<tr>
			<td>STZ (streptozotocin)</td>
			<td>Sigma-Aldrich</td>
			<td>S0130</td>
			<td></td>
		</tr>
		<tr>
			<td>Test Strip</td>
			<td>GenUltimate</td>
			<td>100-50</td>
			<td></td>
		</tr>
		<tr>
			<td>TRITC-conjugated Goat anti-Rabbit IgG(H+L)</td>
			<td>proteintech</td>
			<td>SA00007-2</td>
			<td>Dilution (1:200)</td>
		</tr>
		<tr>
			<td>vascular clamp</td>
			<td>RWD Life Science</td>
			<td>R31006-04</td>
			<td></td>
		</tr>
	</tbody>
</table>

inguinal subcutaneous white adipose tissue (iswat) transplantation model of murine islets

Pancreatic islet transplantation is a well-established therapeutic treatment for type 1 diabetes. The kidney capsule is the most commonly used site for islet transplantation in rodent models. However, the tight kidney capsule limits the transplantation of sufficient islets in large animals and humans. The inguinal subcutaneous white adipose tissue (ISWAT), a new subcutaneous space, was found to be a potentially valuable site for islet transplantation. This site has better blood supply than other subcutaneous spaces. Moreover, the ISWAT accommodates a larger islet mass than the kidney capsule, and transplantation into it is simple. This manuscript describes the procedure of mouse islet isolation and transplantation in the ISWAT site of syngeneic diabetic mouse recipients. Using this protocol, murine pancreatic islets were isolated by standard collagenase digestion and a basement membrane matrix hydrogel was used for fixing the purified islets in the ISWAT site. The blood glucose levels of the recipient mice were monitored for more than 100 days. Islet grafts were retrieved at day 100 after transplantation for histological analysis. The protocol for islet transplantation in the ISWAT site described in this manuscript is simple and effective.

Two procedures are introduced in this protocol: murine islet preparation and islet transplantation into the ISWAT site. In the first procedure, after perfusing and digesting with Type V collagenase solution, purifying with Histopaque-1119 and Histopaque-1077 and an additional hand-picking step, the isolated murine islets will be sufficiently pure for transplantation (as shown in Figure 1) and the isolated islets that have a high viability will be used for transplantation (as shown in <strong...

Watch this Scientific Journal Video about Inguinal Subcutaneous White Adipose Tissue ISWAT Transplantation Model of Murine Islets at JoVE.com

Inguinal Subcutaneous White Adipose Tissue ISWAT Transplantation Model of Murine Islets

In this protocol, a method of murine islet isolation and transplantation into the inguinal subcutaneous white adipose tissue is described. Isolated syngeneic murine islets are transplanted into a murine recipient using a basement membrane hydrogel. The blood glucose level of the recipients is monitored, and histology analysis of the islet grafts is performed.

Inguinal Subcutaneous White Adipose Tissue (ISWAT) Transplantation Model of Murine Islets

Pancreatic islet transplantation is a well-established therapeutic treatment for type 1 diabetes. The kidney capsule is the most commonly used site for ...

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Medicine

6.3K Views.  First Affiliated Hospital of Shenzhen University, Health Science Center. In this protocol, a method of murine islet isolation and transplantation into the inguinal subcutaneous white adipose tissue is described. Isolated syngeneic murine islets are transplanted into a murine recipient using a basement membrane hydrogel. The blood glucose level of the recipients is monitored, and histology analysis of the islet grafts is performed.

Video: Inguinal Subcutaneous White Adipose Tissue ISWAT Transplantation Model of Murine Islets

Development of Obliterative Bronchiolitis in a Murine Model of Orthotopic Lung Transplantation

Orthotopic lung transplantation in rats was first reported by Asimacopoulos and colleagues in 1971 1. Currently, this method is well accepted and standardized not only for the study of allo-rejection but also between syngeneic strains for examining mechanisms of ischemia-reperfusion injury after lung transplantation. Although the application of the rat and other large animal model 2 contributed significantly to the elucidation of these studies, the scope of those investigations is limited by the scarcity of knockout and transgenic rats. Due to no effective therapies for obliterative bronchiolitis, the leading cause of death in lung transplant patients, there has been an intensive search for pre-clinical models that replicate obliterative bronchiolitis. The tracheal allograft model is the most widely used and may reproduce some of the histopathologic features of obliterative bronchiolitis 3. However, the lack of an intact vasculature with no connection to the recipient's conducting airways, and incomplete pathologic features of obliterative bronchiolitis limit the utility of this model 4. Unlike transplantation of other solid organs, vascularized mouse lung transplants have only recently been reported by Okazaki and colleagues for the first time in 2007 5. Applying the basic principles of the rat lung transplant, our lab initiated the obliterative bronchiolitis model using minor histoincompatible antigen murine orthotopic single-left lung transplants which allows the further study of obliterative bronchiolitis immunopathogenesis6.

Obliterative bronchiolitis is the key impediment to the long-term survival of lung transplant recipients and the lack of a robust preclinical model precludes examining obliterative bronchiolitis immunopathogenesis. Unlike other solid organ transplants, vascularized mouse lung transplantation has only recently been developed. Here we show our independently developed obliterative bronchiolitis model after murine orthotopic single-lung transplantation.

Orthotopic lung transplantation in rats was first reported by Asimacopoulos and colleagues in 1971 1. Currently, this method is well accepted and ...

Murine Cervical Heart Transplantation Model Using a Modified Cuff Technique

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are available to perform mechanistic in vivo studies. While heart transplantation models using a suture technique were first successfully developed in rats, the translation into an equally widespread used murine equivalent was never achieved due the technical complexity of the microsurgical procedure. In contrast, non-suture cuff techniques, also developed initially in rats, were successfully adapted for use in mice1-3. This technique for revascularization involves two major steps I) everting the recipient vessel over a polyethylene cuff; II) pulling the donor vessel over the formerly everted recipient vessel and holding it in place with a circumferential tie. This ensures a continuity of the endothelial layer, short operating time and very high patency rates4.
Using this technique for vascular anastomosis we performed more than 1,000 cervical heart transplants with an overall success rate of 95%. For arterial inflow the common carotid artery and the proximal aortic arch were anastomosed resulting in a retrograde perfusion of the transplanted heart. For venous drainage the pulmonary artery of the graft was anastomosed with the external jugular vein of the recipient5.
Herein, we provide additional details of this technique to supplement the video.

The murine cervical heart transplantation model is well suited for immunological as well as ischemia reperfusion injury studies. We modified the procedure using a non-suture cuff technique and performed more than 1,000 successful transplants with this approach.
Herein, we provide additional details of this technique to supplement the video.

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are ...

Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed results. However, the cellular and molecular mechanisms of the neotissue development, valve thickening, and stenosis development are not researched extensively. To answer the above questions, we developed a murine heterotopic heart valve transplantation model. A heart valve was harvested from a valve donor mouse and transplanted to a heart donor mouse. The heart with a new valve was transplanted heterotopically to a recipient mouse. The transplanted heart showed its own heartbeat, independent of the recipient&#8217;s heartbeat. The blood flow was quantified using a high frequency ultrasound system with a pulsed wave Doppler. The flow through the implanted pulmonary valve showed forward flow with minimal regurgitation and the peak flow was close to 100 mm/sec. This murine model of heart valve transplantation is highly versatile, so it can be modified and adapted to provide different hemodynamic environments and/or can be used with various transgenic mice to study neotissue development in a tissue engineered heart valve.

In order to understand the cellular and molecular mechanisms underlying neotissue formation and stenosis development in tissue engineered heart valves, a murine model of heterotopic heart valve transplantation was developed. A pulmonary heart valve was transplanted to recipient using the heterotopic heart transplantation technique.

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed ...

Murine Corneal Transplantation: A Model to Study the Most Common Form of Solid Organ Transplantation

Corneal transplantation is the most common form of organ transplantation in the United States with between 45,000 and 55,000 procedures performed each year. While several animal models exist for this procedure and mice are the species that is most commonly used. The reasons for using mice are the relative cost of using this species, the existence of many genetically defined strains that allow for the study of immune responses, and the existence of an extensive array of reagents that can be used to further define responses in this species. This model has been used to define factors in the cornea that are responsible for the relative immune privilege status of this tissue that enables corneal allografts to survive acute rejection in the absence of immunosuppressive therapy. It has also been used to define those factors that are most important in rejection of such allografts. Consequently, much of what we know concerning mechanisms of both corneal allograft acceptance and rejection are due to studies using a murine model of corneal transplantation. In addition to describing a model for acute corneal allograft rejection, we also present for the first time a model of late-term corneal allograft rejection.

Mice have been used as a model for studying many forms of transplantation, including corneal transplantation. We describe in this report a murine model for both acute and late-term corneal transplantation.

Corneal transplantation is the most common form of organ transplantation in the United States with between 45,000 and 55,000 procedures performed each ...

Encapsulation Thermogenic Preadipocytes for Transplantation into Adipose Tissue Depots

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular weight metabolites in tissues of the treated host to achieve long-term survival. The semipermeable membrane allows engrafted encapsulated cells to avoid rejection by the immune system. The encapsulation procedure was designed to enable a controlled release of bioactive compounds, such as insulin, other hormones, and cytokines. Here we describe a method for encapsulation of catabolic cells, which consume lipids for heat production and energy dissipation (thermogenesis) in the intra-abdominal adipose tissue of obese mice. Encapsulation of thermogenic catabolic cells may be potentially applicable to the prevention and treatment of obesity and type 2 diabetes. Another potential application of catabolic cells may include detoxification from alcohols or other toxic metabolites and environmental pollutants.

Here, we present a protocol for encapsulation of catabolic cells, which consume lipids for heat production in intra-abdominal adipose tissue and increase energy dissipation in obese mice.

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular ...

A Versatile Murine Model of Subcortical White Matter Stroke for the Study of Axonal Degeneration and White Matter Neurobiology

Stroke affecting white matter accounts for up to 25% of clinical stroke presentations, occurs silently at rates that may be 5-10 fold greater, and contributes significantly to the development of vascular dementia. Few models of focal white matter stroke exist and this lack of appropriate models has hampered understanding of the neurobiologic mechanisms involved in injury response and repair after this type of stroke. The main limitation of other subcortical stroke models is that they do not focally restrict the infarct to the white matter or have primarily been validated in non-murine species. This limits the ability to apply the wide variety of murine research tools to study the neurobiology of white matter stroke. Here we present a methodology for the reliable production of a focal stroke in murine white matter using a local injection of an irreversible eNOS inhibitor. We also present several variations on the general protocol including two unique stereotactic variations, retrograde neuronal tracing, as well as fresh tissue labeling and dissection that greatly expand the potential applications of this technique. These variations allow for multiple approaches to analyze the neurobiologic effects of this common and understudied form of stroke.

Here we present methodology for the production of a focal stroke in murine white matter by local injection of an irreversible endothelial nitric oxide synthase (eNOS) inhibitor (L-Nio). Presented are two stereotactic variations, retrograde neuronal tracing, and fresh tissue labeling and dissection that expand the potential applications of this technique.

Stroke affecting white matter accounts for up to 25% of clinical stroke presentations, occurs silently at rates that may be 5-10 fold greater, and ...

A Technique for Subcutaneous Abdominal Adipose Tissue Biopsy via a Non-diathermy Method

Adipose tissue biopsies offer tissue samples that, upon analysis, may provide insightful overviews of mechanisms relating to metabolism and disease. To obtain subcutaneous adipose tissue biopsies in the abdominal area, researchers and physicians use either a surgical or a needle-based technique. However, surgical subcutaneous fat biopsies can offer tissue samples that may provide a more comprehensive overview of the complexities of biological indices in white adipose tissue. Usually, a surgical adipose tissue biopsy includes a diathermy treatment for cauterizing blood vessels to prevent excessive bleeding. Nevertheless, side effects, such as flash fires and skin lesions in the tissue, have been reported after diathermy. Therefore, we aimed to standardize a surgical abdominal adipose tissue biopsy performed under local anesthesia using a non-diathermy method. We conducted 115 subcutaneous adipose tissue biopsies in healthy men using a non-diathermy abdominal surgical biopsy method. Our results showed three cases of excessive post-operation bleeding out of 115 operations (2.61%).In conclusion, our standardized subcutaneous abdominal adipose tissue surgical biopsy using a non-diathermy method can be safely applied to healthy men at the bedside, with minimal side effects.

We standardized an abdominal adipose tissue biopsy using a non-diathermy method performed under local anesthesia. Three cases of excessive post-operation bleeding out of 115 operations (2.61%) occurred.We conclude that an abdominal adipose tissue surgical biopsy using a non-diathermy method can be safely applied to healthy men.

Adipose tissue biopsies offer tissue samples that, upon analysis, may provide insightful overviews of mechanisms relating to metabolism and disease. To ...

Transplantation of Adipose Tissue-Derived Stem Cell Sheet to Reduce Leakage After Partial Colectomy in A Rat Model

Anastomotic leakage is a disastrous complication after colorectal surgery. Although current methods for leakage prevention have different levels of clinical efficacy, they are until now imperfect solutions. Stem cell therapy using ASC sheets could provide a solution to this problem. ASCs are considered as promising candidates for promoting tissue healing because of their trophic and immunomodulatory properties. Here, we provide methods to produce high-density ASC sheets, that are transplanted onto a colorectal anastomosis in a rat model to reduce the leakage. ASCs formed cell sheets in thermo-responsive culture dishes that could be easily detached. On the day of the transplantation, a partial colectomy with a 5-suture colorectal anastomosis was performed. Animals were immediately transplanted with 1 ASC sheet per rat. ASC sheets adhered spontaneously to the anastomosis without any glue, suture, or any biomaterial. Animal groups were sacrificed 3 and 7 days postoperatively. Compared to transplanted animals, the incidence of anastomotic abscesses and leakage was higher in control animals. In our model, the transplantation of ASC sheets after colorectal anastomosis was successful and associated with a lower leakage rate.

The preparation and transplantation of adipose tissue derived stem cell (ASC) sheets onto insufficiently sutured colorectal anastomoses in a rat model is presented. This novel application shows that ASC sheets can reduce colorectal anastomosis leakage.

Anastomotic leakage is a disastrous complication after colorectal surgery. Although current methods for leakage prevention have different levels of ...

Intraportal Transplantation of Pancreatic Islets in Mouse Model

Pancreatic islet transplantation to reduce hyperglycemia is highly successful in rodents with chemically-induced diabetes. The most common transplantation site in experimental islet transplantation is the kidney capsule. However, as less is known about the interaction of pancreatic islets with blood constituents, it also makes sense to utilize the portal vein approach in experimental islet transplantation.
This protocol demonstrates an intraportal islet transplantation technique in NMRI nude mice. Streptozotocin (180 mg/kg) is injected intraperitoneally to induce hyperglycemia in recipient mice. They are considered as diabetic at a non-fasting blood glucose level greater than 20 mmol/L. One day prior to transplantation, mouse pancreatic islets are isolated from the donor pancreas by collagenase digestion; a minimum of 350 islets are utilized per diabetic recipient. Depending upon the islet isolation yield, two or more donor mice are utilized per recipient. After overnight culture at 37 &#176;C, islets are administered into the recipient liver via the portal vein. After surgery, the mice are protected in red Makrolon houses and observed until are awake. This protocol maintains glycemic control for 120 days in syngeneic mice and 15 days in allogeneic mice.

Pancreatic islet transplantation is a way to achieve normoglycemia in type 1 diabetes. This article focuses on the transplantation technique through the intraportal route to maintain normal glucose levels in diabetic mice.

Pancreatic islet transplantation to reduce hyperglycemia is highly successful in rodents with chemically-induced diabetes. The most common transplantation ...

Fat-Covered Islet Transplantation Using Epididymal White Adipose Tissue

Islet transplantation is a cellular replacement therapy for severe diabetes mellitus. The intraperitoneal cavity is typically the transplant site for this procedure. However, intraperitoneal islet transplantation has some limitations, including poor transplant efficacy, difficult graft detection ability, and a lack of graftectomy capability for post-transplant analysis. In this paper, "fat-covered islet transplantation", an intraperitoneal islet transplantation method that utilizes epididymal white adipose tissue, is used to assess the therapeutic effects of bioengineered islets. The simplicity of the method lies in the seeding of islets onto epididymal white adipose tissue and using the tissue to cover the islets. While this method can be categorized as an intraperitoneal islet transplantation technique, it shares characteristics with intra-adipose tissue islet transplantation. The fat-covered islet transplantation method demonstrates more robust therapeutic effects than intra-adipose tissue islet transplantation, however, including the improvement of blood glucose and plasma insulin levels and the potential for graft removal. We recommend the adoption of this method for assessing the mechanisms of islet engraftment into white adipose tissue and the therapeutic effects of bioengineered islets.

This fat-covered islet transplantation method is suitable for the detection of engrafted islets in the intraperitoneal cavity. Notably, it does not require the use of biobinding agents or suturing.

Islet transplantation is a cellular replacement therapy for severe diabetes mellitus. The intraperitoneal cavity is typically the transplant site for this ...