This study was supported by the Department of Veterans Affairs (VA-ORD BLR&#38;D Merit I01BX004536), and the National Institute of Health grants # 1R01DK105183, DK120394, DK118529, to HW. We would like to thank you Mr. Michael Lee and Ms. Lindsay Swaby for language editing

All procedures were conducted with the approval of the Institutional Animal Care and Use Committees at the Medical University of South Carolina and the Ralph H Johnson Medical Center in Charleston.
1. Diabetes induction using streptozotocin (STZ)
<ol>
	<li>Recipient mice preparation:
	<ol>
		<li>Weigh all mice individually.</li>
		<li>Check blood glucose levels from a tail vein blood sample using a glucometer.</li>
	</ol>
	</li>
	<li>STZ dose determination for three different scenarios:
	<ol>
		<li>For mice with fatty liver disease inject one dose of STZ [40 mg/kg/day, intraperitoneal (i.p.) injection]&#160;for 5 consecutive days.</li>
		<li>For NOD-SCID mice inject 125 mg/kg of STZ, single injection, i.p. after overnight fasting.</li>
		<li>For C57BL/6 mice inject 225 mg/kg of STZ, single injection, i.p.</li>
	</ol>
	</li>
	<li>Calculations for STZ (13.5 mg/mL): 
	NOTE: This calculation is for five C57BL/6 mice with body weights of 30 g:
	<ol>
		<li>Total body weights: 5 mice x 30 g/mouse = 150g</li>
		<li>STZ needed: 150 g x 225 mg/1000g STZ = 33.75 mg</li>
	</ol>
	</li>
	<li>STZ preparation:
	<ol>
		<li>Weigh the STZ following the pre-calculated dose.</li>
		<li>Transfer the weighed STZ powder into a 10 mL beaker on ice.</li>
		<li>Add 3 mL of sodium citrate solution to the beaker to dissolve the STZ.</li>
		<li>Mix well,&#160;filter sterilize through a 0.22-&#956;m pore, and use the STZ solution within 10 min of preparation.</li>
	</ol>
	</li>
	<li>STZ injection:
	<ol>
		<li>Load the desired amount of STZ solution (enough for one mouse) into 1 mL syringe.</li>
		<li>Perform intraperitoneal injection at the lower right quadrant of mouse abdomen.</li>
		<li>Observe mice for 5 min after injection and check for any signs of discomfort during this period of time before putting them back into the cages.</li>
		<li>Monitor blood glucose level from a tail vein blood sample using a glucometer daily after the STZ injection. 
		NOTE: In this experiment, mice are considered diabetic when non-fasting blood glucose is &#62; 350 mg/dL for two consecutive days.</li>
	</ol>
	</li>
</ol>
2. Islet preparation
NOTE: Human islets were cultured in CMRL-1066 media supplemented with 10% fetal bovine serum (FBS), and 1% penicillin/streptomycin (P/S) at a density of 10,000 islet equivalent number (IEQ) per 100 mm cell culture dish9. Mouse islets were cultured in DMEM with 10% FBS and 1% P/S with the same density13. Male NOD-SCID and C57BL/7 mice between 6-10 weeks of ages were obtained from commercial sources.
<ol>
	<li>Detach cultured islets from cell culture dish by gentle scratching.</li>
	<li>Hand-pick desired numbers of islets (e.g., 300-350 islets) using a 1cc syringe and put them into sterile 1.5 mL microcentrifuge tubes on ice.</li>
	<li>Spin the tube for 10 seconds using the microcentrifuge.</li>
	<li>Remove the supernatant, leaving some liquid to avoid losing the pellet.</li>
	<li>Resuspend the pellet in 200 &#956;L of HBSS with 0.5% bovine serum albumin (BSA).</li>
	<li>Aspirate the resuspended islets into a 0.5 mL insulin syringe.</li>
	<li>Place the syringe in the upright position. Let the islets sink down for 1 min.</li>
	<li>Push the syringe to remove all the bubbles, leaving about 100-150 &#956;L of liquid containing islets.</li>
	<li>Place syringe head down and gently tap the side of the syringe to let the islets equally distribute throughout the liquid. Islets are now ready for injection.</li>
</ol>
3. Islet transplantation
<ol>
	<li>Induce and maintain the mouse under general anesthesia with 2% isoflurane. Check for the lack of pedal reflexes to ensure proper anesthetization of the animal.</li>
	<li>Shave and remove the fur in the abdomen area of the mouse.</li>
	<li>Administer a single pre-operative dose of Buprenorphine (0.1 mg/kg i.p.).</li>
	<li>Disinfect the surgical area with three alternating wipes of 2% iodine and 75% alcohol.</li>
	<li>Perform a laparotomy with micro scissors to generate a 1-1.5 cm incision.</li>
	<li>Open the peritoneal cavity with a retractor. Follow with either method A or method B as detailed below.</li>
</ol>
4. Method A: (stop bleeding with gel foam,&#160;&#160;Figure 1A)14,15,16
<ol>
	<li>Mouse preparation
	<ol>
		<li>Place a sterile gauze around the incision.</li>
		<li>Gently pull out the intestine using a forceps and keep it on the gauze.</li>
		<li>Identify the portal vein by its location and expose it well.</li>
		<li>Cover the intestine with a warm saline-wet gauze during the entire surgery.</li>
	</ol>
	</li>
	<li>Insert the islet preloaded insulin syringe needle through the portal vein near the duodenum (Figure 1B). To do so, hold the needle with the hole (bevel) facing down and position the opening surface&#39;s angle parallel to the portal vein wall before penetrating through the wall.
	<ol>
		<li>Pull the plunger to draw some blood (20-50 &#956;L) into the syringe to mix the islets first.</li>
		<li>Infuse the islets into the portal vein slowly while repeatedly pulling and pushing the plunge.</li>
		<li>Place a piece of gel foam (about 0.5 cm x 0.5 cm in size) to cover the injection site.</li>
		<li>Press the gel foam down with a cotton tip while pulling out the needle from the portal vein.</li>
		<li>Continue pressing on the gel for about 2 min to confirm there is no active bleeding.</li>
		<li>Rollover the cotton tip over and away from&#160;the gel foam to make sure the gel foam covers the portal vein well.</li>
	</ol>
	</li>
</ol>
5. Method B: (stop bleeding with fat pad,&#160;&#160;Figure 1C)17
<ol>
	<li>Expose the portal vein thoroughly.
	<ol>
		<li>Use two cotton tips to hold the exposed portal vein from both the left and the right sides.</li>
		<li>Identify the fat tissue pad between the duodenum and the portal vein.</li>
		<li>Penetrate through the fat pad before inserting the needle into the portal vein (Figure 1D).</li>
		<li>Infuse the islets, following the similar procedure described above in part 4.2.1 and 4.2.2 of Method A.</li>
		<li>Pull out the needle while pressing down on the fat with a cotton tip.</li>
		<li>Continue pressing on the fat pad for 1 min after removing the needle.</li>
	</ol>
	</li>
	<li>After confirming that there is no bleeding from the portal vein, gently return the intestine to the peritoneal cavity in its original position.</li>
	<li>Leave 0.5 mL of warm saline (36-37 &#176;C) in the abdominal cavity before closure. 
	NOTE: Warm saline facilitates post-surgery intestine movement and recovery and prevents intestine necrosis.</li>
	<li>Close the muscle layer with an 5-0 suture.</li>
	<li>Close the skin layer with an 4-0 suture.</li>
	<li>Place the mouse in a clean cage on a heating pad until fully recovered from anesthesia.</li>
	<li>Continue to provide an analgesic (e.g., buprenorphine 0.1 mg/kg i.p.) every 12 h and supplemental heat for 48 h post-surgery. 
	&#8203;NOTE: The islet transplantation procedure takes approximately 15-20 min to complete.</li>
</ol>
6. H&#38;E staining and photograph of whole liver section
<ol>
	<li>Liver perfusion
	<ol>
		<li>Put the mouse under anesthesia as described above in part 3.1.</li>
		<li>Carefully expose the portal vein and cut the inferior vena cava.</li>
		<li>Manually perfuse the liver using 20 mL of 10% paraformaldehyde via the portal vein for about 5 minutes, using a 20 mL syringe with 25G needle18. 
		NOTE: Liver perfusion can remove blood from liver tissue and improve liver fixation without disturbing the islet grafts.</li>
		<li>Dissect the perfused whole liver from other organs.</li>
		<li>Fix the perfused liver tissue in 10% paraformaldehyde for 24 h.</li>
		<li>Embed the tissue in paraffin.</li>
		<li>Cut tissue sections of 5 &#181;m thickness each and put them on a glass slide for staining.</li>
		<li>Perform H&#38;E, insulin, fibrin, and polymorphonuclear neutrophil (PMN) staining using standard methods15,16.</li>
		<li>Scan whole liver section under a microscope.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Pellegrini, S., Cantarelli, E., Sordi, V., Nano, R., Piemonti, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+state+of+the+art+of+islet+transplantation+and+cell+therapy+in+type+1+diabetes.">The state of the art of islet transplantation and cell therapy in type 1 diabetes.</a> Acta Diabetology. 53 (5), 683-691 (2016).</li><li>Ballinger, W. F., Lacy, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transplantation+of+intact+pancreatic+islets+in+rats.">Transplantation of intact pancreatic islets in rats.</a> Surgery. 72 (2), 175-186 (1972).</li><li>Wright, J. R., Hauptfeld, V., Lacy, P. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+Ia+antigen+expression+on+murine+islet+parenchymal+cells+does+not+diminish+islet+allograft+survival.">Induction of Ia antigen expression on murine islet parenchymal cells does not diminish islet allograft survival.</a> American Journal of Pathology. 134 (2), 237-242 (1989).</li><li>Toyofuku, 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=Natural+killer+T-cells+participate+in+rejection+of+islet+allografts+in+the+liver+of+mice.">Natural killer T-cells participate in rejection of islet allografts in the liver of mice.</a> Diabetes. 55 (1), 34-39 (2006).</li><li>Goss, J. A., Nakafusa, Y., Finke, E. H., Flye, M. W., Lacy, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+tolerance+to+islet+xenografts+in+a+concordant+rat-to-mouse+model.">Induction of tolerance to islet xenografts in a concordant rat-to-mouse model.</a> Diabetes. 43 (1), 16-23 (1994).</li><li>Hara, 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=A+mouse+model+for+studying+intrahepatic+islet+transplantation.">A mouse model for studying intrahepatic islet transplantation.</a> Transplantation. 78 (4), 615-618 (2004).</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>Wang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alpha-1+antitrypsin+enhances+islet+engraftment+by+suppression+of+instant+blood-mediated+inflammatory+reaction.">Alpha-1 antitrypsin enhances islet engraftment by suppression of instant blood-mediated inflammatory reaction.</a> Diabetes. 66 (4), 970-980 (2017).</li><li>Gou, W., 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=Alpha-1+antitrypsin+suppresses+macrophage+activation+and+promotes+islet+graft+survival+after+intrahepatic+islet+transplantation.">Alpha-1 antitrypsin suppresses macrophage activation and promotes islet graft survival after intrahepatic islet transplantation.</a> American Journal of Transplantation. , (2020).</li><li>Contreras, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activated+protein+C+preserves+functional+islet+mass+after+intraportal+transplantation:+A+novel+link+between+endothelial+cell+activation,+thrombosis,+inflammation,+and+islet+cell+death.">Activated protein C preserves functional islet mass after intraportal transplantation: A novel link between endothelial cell activation, thrombosis, inflammation, and islet cell death.</a> Diabetes. 53 (11), 2804-2814 (2004).</li><li>Moberg, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+tissue+factor+by+pancreatic+islet+cells+as+a+trigger+of+detrimental+thrombotic+reactions+in+clinical+islet+transplantation.">Production of tissue factor by pancreatic islet cells as a trigger of detrimental thrombotic reactions in clinical islet transplantation.</a> Lancet. 360 (9350), 2039-2045 (2002).</li><li>Melzi, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intrahepatic+islet+transplant+in+the+mouse:+functional+and+morphological+characterization.">Intrahepatic islet transplant in the mouse: functional and morphological characterization.</a> Cell Transplantation. 17 (12), 1361-1370 (2008).</li><li>Wang, 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=Donor+treatment+with+carbon+monoxide+can+yield+islet+allograft+survival+and+tolerance.">Donor treatment with carbon monoxide can yield islet allograft survival and tolerance.</a> Diabetes. 54 (5), 1400-1406 (2005).</li><li>Desai, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+liver+histopathology+on+islet+cell+engraftment+in+the+model+mimicking+autologous+islet+cell+transplantation.">Effect of liver histopathology on islet cell engraftment in the model mimicking autologous islet cell transplantation.</a> Islets. 9 (6), 140-149 (2017).</li><li>Cui, W., Angsana, J., Wen, J., Chaikof, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liposomal+formulations+of+thrombomodulin+increase+engraftment+after+intraportal+islet+transplantation.">Liposomal formulations of thrombomodulin increase engraftment after intraportal islet transplantation.</a> Cell Transplantation. 19 (11), 1359-1367 (2010).</li><li>Cui, W., 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=Thrombomodulin+improves+early+outcomes+after+intraportal+islet+transplantation.">Thrombomodulin improves early outcomes after intraportal islet transplantation.</a> American Journal of Transplantation. 9 (6), 1308-1316 (2009).</li><li>Proto, C., Grasso, G., Fassio, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hepatoparenchymal+clearance+of+indocyanine+green+in+infectious+hepatitis.">Hepatoparenchymal clearance of indocyanine green in infectious hepatitis.</a> Giornale di Malattie Infettive e Parassitarie. 20 (9), 845-851 (1968).</li><li>Cabral, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+hepatocytes+and+sinusoidal+endothelial+cells+from+mouse+liver+perfusion.">Purification of hepatocytes and sinusoidal endothelial cells from mouse liver perfusion.</a> Journal of Visualized Experiments. (132), e56993 (2018).</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>Wang, 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=Autologous+mesenchymal+stem+cell+and+islet+cotransplantation:+Safety+and+efficacy.">Autologous mesenchymal stem cell and islet cotransplantation: Safety and efficacy.</a> Stem Cells Translational Medicine. 7 (1), 11-19 (2018).</li></ol>

All authors declare that they do not have conflict of interest.

In this study, two improved procedures that can prevent bleeding and may reduce mouse mortality during mouse IIT have been demonstrated. This study enables researchers to visualize the islet transplantation model that is unique in studying the instant blood mediated inflammatory response after transplantation. The IIT model is a distinctive model for studying islet cell survival and hepatic ischemic injuries in response to islet transplantation19. Here, we refined the procedure based on previous studies and reduced early complication-induced mouse mortality. Both method A14,15,16&#160;and method B8,9 were used in multiple studies. We showed that islets distributed among the whole liver, and neutrophil infiltration and thrombosis typically associated with IIT were prominent in graft immediately after transplantation.
There are several key steps in mouse hepatic islet transplantation. Because both human and mouse islets can be as large as 200 &#956;m in size, a needle size of at least 27G must be used for transplantation to ensure the islet products&#39; smooth flow. However, this would generate a large hole in the portal vein that may cause bleeding after needle removal. By injecting islets via the correct angle and using a dental sponge to block the injection site or injection through the fat tissue, the chance of bleeding can be minimized, and mice have higher survival rates after transplantation. These steps may also help avoid liver warm ischemia-reperfusion injuries caused by blockage of portal vein blood flow when performing this procedure19. They can also reduce the damages to the liver and the intestines that may contribute to mouse mortality post-surgery.
There are also several limitations of the mouse intrahepatic islet transplantation model compared to the human islet transplantations setting. First, we cannot monitor mouse portal vein pressure during islet infusion as we do in clinic settings. Second, the volume that can be transplanted into the mice may not reflect the high amount of islet product transplanted into a human. Therefore, the extent of thrombosis may be different. Thirdly, mouse islet grafts after transplantation will be temporarily exposed to a hyperglycemic environment since no insulin will be given to mice, while in humans20, insulin would be given during the peri-transplantation period to reduce the stress of transplanted islets20. Nevertheless, the intrahepatic islet model offers a unique pre-clinical model that can be used to study human islet transplantation.

Intraportal islet transplantation (IIT) via the portal vein is the most commonly used method for human islet transplantation in clinical settings. The mouse IIT model offers a great opportunity to study islet transplantation and test promising interventional approaches that can enhance the efficacy of islet transplantation1. IIT was first described in the 1970s and used by several groups1,2,3,4,5. It regained popularity after the breakthrough in human islet transplantation in the year 20006,7. However, most islet transplant studies used the kidney capsule as a preferred site for experimental islet transplantation due to its easy success. On the contrary, IIT is more technically challenging and less frequently used for islet transplantation studies8,9. Unlike IIT, however, islets transplanted under the kidney capsule do not suffer from the immediate blood-mediated inflammatory reaction characterized by thrombosis, inflammation, and hepatic tissue ischemia, and thus have better function than islets transplanted into the liver. The kidney capsule model, therefore, may not fully mimic the stresses encountered by islets in human islet transplantation10,11,12.
One of the major complications of IIT in mice is bleeding from the injection site after transplantation, which could cause 10-30% of mortality among different mouse strains12. In this paper, two refined approaches have been developed to stop bleeding more rapidly and securely and to reduce mouse mortality after an IIT. Visual demonstration of these refined details will help researchers identify the key steps of this technically challenging procedure.&#160;In addition, the location of the islet grafts in the recipient&#8217;s liver was determined by histological examination of the Hematoxylin and Eosin (H&#38;E) stained liver tissue (whole section) bearing transplanted islets.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>10% Neutral buffered formalin v/v</td>
			<td>Fisher Scientific</td>
			<td>23426796</td>
			<td></td>
		</tr>
		<tr>
			<td>1 mL Syringe with needle</td>
			<td>AHS</td>
			<td>AH01T</td>
			<td></td>
		</tr>
		<tr>
			<td>20 mL Syringe</td>
			<td>BD</td>
			<td>301031</td>
			<td></td>
		</tr>
		<tr>
			<td>25G x 5/8&#34; hypodermic needles</td>
			<td>BD</td>
			<td>305122</td>
			<td></td>
		</tr>
		<tr>
			<td>Alcohol prep pads, sterile</td>
			<td>Fisher Scientific</td>
			<td>22-363-750</td>
			<td></td>
		</tr>
		<tr>
			<td>Animal Anesthesia system</td>
			<td>VetEquip, Inc.</td>
			<td>901806</td>
			<td></td>
		</tr>
		<tr>
			<td>Buprenorphine hydrochloride, injection</td>
			<td>Par Sterile Products, LLC</td>
			<td>NDC 42023-179-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge tubes, 15 mL</td>
			<td>Fisher Scientific</td>
			<td>0553859A</td>
			<td></td>
		</tr>
		<tr>
			<td>CMRL-1066</td>
			<td>Corning</td>
			<td>15110CV</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Corning</td>
			<td>10013CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol, absolute (200 proof), molecular biology grade</td>
			<td>Fisher Scientific</td>
			<td>BP2818500</td>
			<td></td>
		</tr>
		<tr>
			<td>Extra fine Micro Dissecting scissors 4&#8221; straight sharp</td>
			<td>Roboz Surgical Instrument Co.</td>
			<td>RS-5882</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)</td>
			<td>Corning</td>
			<td>35011CV</td>
			<td></td>
		</tr>
		<tr>
			<td>FreeStyle&#160; Glucose meter</td>
			<td>Abbott</td>
			<td>Lite</td>
			<td></td>
		</tr>
		<tr>
			<td>FreeStyle Blood Glucose test strips</td>
			<td>Abbott</td>
			<td>Lite</td>
			<td></td>
		</tr>
		<tr>
			<td>Gelfoam (absorbable gelatin sponge, USP)</td>
			<td>Pharmacia &#38; Upjohn Company</td>
			<td>34201</td>
			<td></td>
		</tr>
		<tr>
			<td>Graefe forceps 4&#8221; extra delicate tip</td>
			<td>Roboz Surgical Instrument Co.</td>
			<td>RS-5136</td>
			<td></td>
		</tr>
		<tr>
			<td>Heated pad</td>
			<td>Amazon</td>
			<td>B07HMKMBKM</td>
			<td></td>
		</tr>
		<tr>
			<td>Hegar-Baumgartner Needle Holder 5.25&#8221;</td>
			<td>Roboz Surgical Instrument Co.</td>
			<td>RS-7850</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin syringe with 27-gauge needle</td>
			<td>BD</td>
			<td>879588</td>
			<td></td>
		</tr>
		<tr>
			<td>Iodine prep pads</td>
			<td>Fisher Scientific</td>
			<td>19-027048</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Piramal Critical Care</td>
			<td>NDC 66794-017-25</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/streptomycin (P/S)</td>
			<td>HyClone</td>
			<td>SV30010</td>
			<td></td>
		</tr>
		<tr>
			<td>Polypropylene Suture 4-0</td>
			<td>Med-Vet International</td>
			<td>MV-8683</td>
			<td></td>
		</tr>
		<tr>
			<td>Polypropylene Suture 5-0</td>
			<td>Med-Vet International</td>
			<td>MV-8661</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium chloride, 0.9% intravenous solution</td>
			<td>VWR</td>
			<td>2B1322Q</td>
			<td></td>
		</tr>
		<tr>
			<td>Streptozocin (STZ)</td>
			<td>Sigma</td>
			<td>S0130</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical drape, sterile</td>
			<td>Med-Vet International</td>
			<td>DR1826</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue Cassette</td>
			<td>Fisher Scientific</td>
			<td>22-272416</td>
			<td></td>
		</tr>
	</tbody>
</table>

minimizing post-infusion portal vein bleeding during intrahepatic islet transplantation in mice

Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the kidney capsule in most rodent preclinical islet transplantation studies. This model is commonly used because murine intrahepatic islet transplantation is technically challenging, and a high percentage of mice could die from surgical complications, especially bleeding from the injection site post-transplantation. In this study, two procedures that can minimize the incidence of post-infusion portal vein bleeding are demonstrated. The first method applies an absorbable hemostatic gelatin sponge to the injection site, and the second method involves penetrating the islet injection needle through the fat tissue first and then into the portal vein by using the fat tissue as a physical barrier to stop bleeding. Both methods could effectively prevent bleeding-induced mouse death. The whole liver section showing islet distribution and evidence of islet thrombosis post-transplantation, a typical feature for intrahepatic islet transplantation, were presented. These improved protocols refine the intrahepatic islet transplantation procedures and may help laboratories set up the procedure to study islet survival and function in pre-clinical settings.

We performed syngeneic and xenogeneic islet transplantations via the portal vein. Islet graft function was observed in a dose-dependent manner in both islet transplantation models. In the syngeneic islet transplantation model using C57BL/6 mice, transplantation of 250 islets led to transitory normoglycemia before mice returned to hyperglycemia. Mice receiving 500 islets reached and maintained normoglycemia beyond 30 days after transplantation (Figure 2A). Mice in both groups showed increased body weights (Figure 2B).
Similarly, in the human islets to diabetic NOD-SCID mouse islet transplantation model, islet graft function was compared when 45, 85, or 140 IEQs/kg of body weights were transplanted. Normoglycemia could not be achieved when 45 IEQ/g (~225-275 islets/mouse) human islets were transplanted. When the islet number increased to 85 IEQ/g (~ 400-450 islets/mouse), 35.7% (10/28) of the recipients achieved normoglycemia (p =0.02 vs. 45 IEQ/g group) at day 60 post-transplantation. Furthermore, 83.3% (5/6) of the recipients who received 140 IEQ/g (~ 600-650 islets/mouse) of human islets reached normoglycemia (Figure 2C). In addition, majority mice who had bleeding died after surgery while mice without bleeding survived (Figure 2D).
Once enough human islets are engrafted to NOD-SCID recipients, their blood glucose levels can be well-controlled at the early-stage post-transplantation and well-maintained until the end of the study. The grafted islets can be easily identified by H&#38;E and insulin staining. At 28 days post-transplantation, transplanted human islets were distributed evenly throughout the whole liver, mostly around/close to a blood vessel (Figure 3).
The intrahepatic model was used to demonstrate instant blood mediated inflammatory reaction as seen in human islet transplantation. In our tissue section, we observed expression of insulin, and presence of fibrin and Polymorphonuclear leukocytes&#160;infiltration in transplanted islets (Figure 4A-D).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62530/62530fig1v2.jpg" /> 
Figure 1: Illustration of intrahepatic islet transplantation procedures. (A, C). Schematics of key steps used in Method A and Method B. (B, D). Islets were injected directly via the portal vein (C) or indirectly via fat pat (D). <a href="https://www.jove.com/files/ftp_upload/62530/62530fig1v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/62530/62530fig02.jpg" /> 
Figure 2:&#160;Representative outcomes of intraportal islet transplantation. (A, B). Syngeneic mouse islet intraportal transplantation. Pancreatic islets (250 or 500) from C57BL/6 mice were transplanted into male C57BL/6 mice that were rendered diabetic by STZ. (A) Serial blood glucose levels were measured. Normoglycemia was defined as glucose levels &#60;200 mg/dL for &#62;2 consecutive days. (B) Increase in the recipients&#39; body weight was observed post islet transplantation. (C) Percentage of diabetic NOD-SCID mice reaching normoglycemia in mice receiving a different number of human islets at 45 IEQ/g (n=7), 85 IEQ/g (n=28), and 140 IEQ/g (n=6). (D) Percentage of survival after IIT in bleeding and non-bleeding mice (n=14 each). <a href="https://www.jove.com/files/ftp_upload/62530/62530fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/62530/62530fig3v5.jpg" /> 
Figure 3: H&#38;E staining of liver sections of NOD-SCID liver bearing human islet graft at 28 days post-transplantation. Islets are marked by black circles. The diameter of each circle positively corresponds with the size of each islet. Scale bar =1,000 &#956;m in whole liver section and 100 &#956;m in inset. <a href="https://www.jove.com/files/ftp_upload/62530/62530fig3v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/62530/62530fig4v2.jpg" /> 
Figure 4: Representative histological pictures of intraportal transplanted mouse islets in liver 6 h after intraportal transplantation. (A) H&#38;E, (B) insulin (red) (C) Fibrin, and (D) PMN stains. Scale bar = 100 &#956;m.&#160;<a href="https://www.jove.com/files/ftp_upload/62530/62530fig4v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Minimizing Post-Infusion Portal Vein Bleeding during Intrahepatic Islet Transplantation in Mice at JoVE.com

Minimizing Post-Infusion Portal Vein Bleeding during Intrahepatic Islet Transplantation in Mice

Here we present refined surgical procedures on successfully performing intraportal islet transplantation, a clinically relevant but technically challenging surgical procedure, in mice.

Although the liver is currently accepted as the primary transplantation site for human islets in clinical settings, islets are transplanted under the ...

minimizing-post-infusion-portal-vein-bleeding-during-intrahepatic

Nanyang Technological University

Research

JoVE Journal

Medicine

3.6K Views.  Medical University of South Carolina. Here we present refined surgical procedures on successfully performing intraportal islet transplantation, a clinically relevant but technically challenging surgical procedure, in mice.

Video: Minimizing Post-Infusion Portal Vein Bleeding during Intrahepatic Islet Transplantation in Mice

A Method for Murine Islet Isolation and Subcapsular Kidney Transplantation

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize their blood glucose levels, islet transplantation has been proposed to be a potential treatment for type 1 diabetes 1,2. More recently, advances in human islet transplantation have further strengthened this view 1,3. However, two major limitations prevent islet transplantation from being a widespread clinical reality: (a) the requirement for large numbers of islets per patient, which severely reduces the number of potential recipients, and (b) the need for heavy immunosuppression, which significantly affects the pediatric population of patients due to their vulnerability to long-term immunosuppression. Strategies that can overcome these limitations have the potential to enhance the therapeutic utility of islet transplantation.
Islet transplantation under the mouse kidney capsule is a widely accepted model to investigate various strategies to improve islet transplantation. This experiment requires the isolation of high quality islets and implantation of islets to the diabetic recipients. Both procedures require surgical steps that can be better demonstrated by video than by text. Here, we document the detailed steps for these procedures by both video and written protocol. We also briefly discuss different transplantation models: syngeneic, allogeneic, syngeneic autoimmune, and allogeneic autoimmune.

Transplantation of isolated islets has been proposed to be a potential treatment for type 1 diabetes. Here we describe a method to isolate islets from mouse pancreata and transplant them to the subcapsular space of the kidney.

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize ...

3-Dimensional Resin Casting and Imaging of Mouse Portal Vein or Intrahepatic Bile Duct System

In organs, the correct architecture of vascular and ductal structures is indispensable for proper physiological function, and the formation and maintenance of these structures is a highly regulated process. The analysis of these complex, 3-dimensional structures has greatly depended on either 2-dimensional examination in section or on dye injection studies. These techniques, however, are not able to provide a complete and quantifiable representation of the ductal or vascular structures they are intended to elucidate. Alternatively, the nature of 3-dimensional plastic resin casts generates a permanent snapshot of the system and is a novel and widely useful technique for visualizing and quantifying 3-dimensional structures and networks.
A crucial advantage of the resin casting system is the ability to determine the intact and connected, or communicating, structure of a blood vessel or duct. The structure of vascular and ductal networks are crucial for organ function, and this technique has the potential to aid study of vascular and ductal networks in several ways. Resin casting may be used to analyze normal morphology and functional architecture of a luminal structure, identify developmental morphogenetic changes, and uncover morphological differences in tissue architecture between normal and disease states. Previous work has utilized resin casting to study, for example, architectural and functional defects within the mouse intrahepatic bile duct system that were not reflected in 2-dimensional analysis of the structure1,2, alterations in brain vasculature of a Alzheimer's disease mouse model3, portal vein abnormalities in portal hypertensive and cirrhotic mice4, developmental steps in rat lymphatic maturation between immature and adult lungs5, immediate microvascular changes in the rat liver, pancreas, and kidney in response in to chemical injury6.
Here we present a method of generating a 3-dimensional resin cast of a mouse vascular or ductal network, focusing specifically on the portal vein and intrahepatic bile duct. These casts can be visualized by clearing or macerating the tissue and can then be analyzed. This technique can be applied to virtually any vascular or ductal system and would be directly applicable to any study inquiring into the development, function, maintenance, or injury of a 3-dimensional ductal or vascular structure.

A method of visualizing and quantifying the 3-dimensional structure of mouse hepatic portal vein or intrahepatic bile duct is described. This resin cast technique can also be applied to other ductal or vascular systems and allows for in situ visualization or quantification of a system's intact communicating architecture.

In  organs, the correct architecture of vascular and ductal structures is  indispensable for proper physiological function, and the formation and  ...

Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation

Cryoballoon ablation (CBA) is an established therapy for atrial fibrillation (AF). Pulmonary vein (PV) occlusion is essential for achieving antral contact and PV isolation and is typically assessed by contrast injection. We present a novel method of direct pressure monitoring for assessment of PV occlusion.
Transcatheter pressure is monitored during balloon advancement to the PV antrum. Pressure is recorded via a single pressure transducer connected to the inner lumen of the cryoballoon. Pressure curve characteristics are used to assess occlusion in conjunction with fluoroscopic or intracardiac echocardiography (ICE) guidance. PV occlusion is confirmed when loss of typical left atrial (LA) pressure waveform is observed with recordings of PA pressure characteristics (no A wave and rapid V wave upstroke). Complete pulmonary vein occlusion as assessed with this technique has been confirmed with concurrent contrast utilization during the initial testing of the technique and has been shown to be highly accurate and readily reproducible.
We evaluated the efficacy of this novel technique in 35 patients. A total of 128 veins were assessed for occlusion with the cryoballoon utilizing the pressure monitoring technique; occlusive pressure was demonstrated in 113 veins with resultant successful pulmonary vein isolation in 111 veins (98.2%). Occlusion was confirmed with subsequent contrast injection during the initial ten procedures, after which contrast utilization was rapidly reduced or eliminated given the highly accurate identification of occlusive pressure waveform with limited initial training.
Verification of PV occlusive pressure during CBA is a novel approach to assessing effective PV occlusion and it accurately predicts electrical isolation. Utilization of this method results in significant decrease in fluoroscopy time and volume of contrast.

Effective pulmonary vein isolation utilizing a cryoballoon depends on complete pulmonary vein occlusion. The point of occlusion can be effectively predicted by direct analysis of pulmonary vein pressure waveform analysis during balloon inflation using a simple and reproducible technique.

Cryoballoon  ablation (CBA) is an established therapy for atrial fibrillation (AF).  Pulmonary vein (PV) occlusion is essential for achieving antral ...

Generation of Subcutaneous and Intrahepatic Human Hepatocellular Carcinoma Xenografts in Immunodeficient Mice

In vivo experimental models of hepatocellular carcinoma (HCC) that recapitulate the human disease provide a valuable platform for research into disease pathophysiology and for the preclinical evaluation of novel therapies. We present a variety of methods to generate subcutaneous or orthotopic human HCC xenografts in immunodeficient mice that could be utilized in a variety of research applications. With a focus on the use of primary tumor tissue from patients undergoing surgical resection as a starting point, we describe the preparation of cell suspensions or tumor fragments for xenografting. We describe specific techniques to xenograft these tissues i) subcutaneously; or ii) intrahepatically, either by direct implantation of tumor cells or fragments into the liver, or indirectly by injection of cells into the mouse spleen. We also describe the use of partial resection of the native mouse liver at the time of xenografting as a strategy to induce a state of active liver regeneration in the recipient mouse that may facilitate the intrahepatic engraftment of primary human tumor cells. The expected results of these techniques are illustrated. The protocols described have been validated using primary human HCC samples and xenografts, which typically perform less robustly than the well-established human HCC cell lines that are widely used and frequently cited in the literature. In comparison with cell lines, we discuss factors which may contribute to the relatively low chance of primary HCC engraftment in xenotransplantation models and comment on technical issues that may influence the kinetics of xenograft growth. We also suggest methods that should be applied to ensure that xenografts obtained accurately resemble parent HCC tissues.

Human tumor xenografts in immunodeficient mice are valuable tools to study cancer biology. Specific protocols to generate subcutaneous and intrahepatic xenografts from human hepatocellular carcinoma cells or tumor fragments are described. Liver regeneration induced by partial hepatectomy in recipient mice is presented as a strategy to facilitate intrahepatic engraftment.

In  vivo experimental models of hepatocellular carcinoma (HCC) that recapitulate  the human disease provide a valuable platform for research into disease  ...

Heterotopic Auxiliary Rat Liver Transplantation With Flow-regulated Portal Vein Arterialization in Acute Hepatic Failure

In acute hepatic failure auxiliary liver transplantation is an interesting alternative approach. The aim is to provide a temporary support until the failing native liver has regenerated.1-3 The APOLT-method, the orthotopic implantation of auxiliary segments- averts most of the technical problems. However this method necessitates extensive resections of both the native liver and the graft.4 In 1998, Erhard developed the heterotopic auxiliary liver transplantation (HALT) utilizing portal vein arterialization (PVA) (Figure 1). This technique showed promising initial clinical results.5-6 We developed a HALT-technique with flow-regulated PVA in the rat to examine the influence of flow-regulated PVA on graft morphology and function (Figure 2).
A liver graft reduced to 30 % of its original size, was heterotopically implanted in the right renal region of the recipient after explantation of the right kidney.&#160; The infra-hepatic caval vein of the graft was anastomosed with the infrahepatic caval vein of the recipient. The arterialization of the donor&#8217;s portal vein was carried out via the recipient&#8217;s right renal artery with the stent technique. The blood-flow regulation of the arterialized portal vein was achieved with the use of a stent with an internal diameter of 0.3 mm. The celiac trunk of the graft was end-to-side anastomosed with the recipient&#8217;s aorta and the bile duct was implanted into the duodenum. A subtotal resection of the native liver was performed to induce acute hepatic failure. 7
In this manner 112 transplantations were performed. The perioperative survival rate was 90% and the 6-week survival rate was 80%. Six weeks after operation, the native liver regenerated, showing an increase in weight from 2.3&#177;0.8 g to 9.8&#177;1 g. At this time, the graft&#8217;s weight decreased from 3.3&#177;0.8 g to 2.3&#177;0.8 g.
We were able to obtain promising long-term results in terms of graft morphology and function. HALT with flow-regulated PVA reliably bridges acute hepatic failure until the native liver regenerates.

Auxiliary liver transplantation provides a temporary support in acute hepatic failure, until regeneration of the failing liver. The heterotopic auxiliary liver transplantation (HALT) with portal vein arterialization (PVA) renders sufficient liver function. We developed an analogous technique in the rat, to examine the influence of the portal vein arterialization on the morphology and function of the graft.

In acute hepatic failure auxiliary liver transplantation is an interesting alternative approach. The aim is to provide a temporary support until the ...

Heterotopic Cervical Heart Transplantation in Mice

The heterotopic cervical heart transplantation in mice is a valuable tool in transplant and cardiovascular research. The cuff technique greatly simplifies this model by avoiding challenging suture anastomoses of small vessels thereby reducing warm ischemia time. In comparison to abdominal graft implantation the cervical model is less invasive and the implanted graft is easily accessible for further follow-up examinations. Anastomoses are performed by pulling the ascending aorta of the graft over the cuff with the recipient&#8217;s common carotid artery and by pulling the main pulmonary artery over the cuff with the external jugular vein. Selection of appropriate cuff size and complete mobilization of the vessels are important for successful revascularization. Ischemia-reperfusion (I/R) injury can be minimized by perfusing the graft with a cardioplegic solution and by hypothermia. In this article, we provide technical details for a simplified and improved cuff technique, which should allow surgeons with basic microsurgical skills to perform the procedure with a high success rate.

The cuff technique shortens and facilitates the model of heterotopic cervical heart transplantation in mice by avoiding technically challenging suture anastomoses of small vessels. The technical details shown in this video paper should allow researches to establish this model in their laboratories.

The heterotopic cervical heart transplantation in mice is a valuable tool in transplant and cardiovascular research. The cuff technique greatly simplifies ...

Using the Sleeve Technique in a Mouse Model of Aortic Transplantation - An Instructional Video

Orthotopic aortic transplantation using the sleeve technique reduces injury to the aorta with failure rate of only 10-20%. The time to anastomose the aorta in mice using the sleeve method was short and easy averaging 20 min, permitting studies of iso/allo grafts. The following article describes the aortic transplantation procedure used in our laboratory. The mice were anesthetized with a mixture of 1.5% volume isoflurane and 100% oxygen through a face mask. At this point, the segment of the aorta between the renal arteries and its bifurcation was separated from the vena cava, freely prepared and clampedat the proximal and distal segments with a single silk suture. Prior to the removal of the aorta, a saline solution containing heparin was injected into the inferior vena cava. Then the aorta was cut between the clamps and a saline heparin solution was used to flush the lumen. The sleeve technique with monofilament sutures was used in order to transplant the abdominal aorta in the orthotopic position.

We present an orthotopic aortic transplantation model using the sleeve technique in mice. It is a very rapid anastomosis method, which can be employed in studies of vascular disease.

Orthotopic aortic transplantation using the sleeve technique reduces injury to the aorta with failure rate of only 10-20%. The time to anastomose the ...

Rat Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) Procedure

Recent clinical data support an aggressive surgical approach to both primary and metastatic liver tumors. For some indications, like colorectal liver metastases, the amount of liver tissue left behind after liver resection has become the main limiting factor of resectability of large or multiple liver tumors. A minimal amount of functional tissue is required to avoid the severe complication of post-hepatectomy liver failure, which has high morbidity and mortality. Inducing liver growth of the prospective remnant prior to resection has become more established in liver surgery, either in the form of portal vein embolization by interventional radiologists or in the form of portal vein ligation several weeks prior to resection. Recently, it was shown that liver regeneration is more extensive and rapid, when the parenchymal transection is added to portal vein ligation in a first stage and then, after only one week of waiting, resection performed in a second stage (Associating Liver Partition and Portal vein ligation for Staged hepatectomy = ALPPS). ALPPS has rapidly become popular across the world, but has been criticized for its high perioperative mortality. The mechanism of accelerated and extensive growth induced by this procedure has not been well understood. Animal models have been developed to explore both the physiological and molecular mechanisms of accelerated liver regeneration in ALPPS. This protocol presents a rat model that allows mechanistic exploration of accelerated regeneration.

Rat Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy ALPPS Procedure

Inducing rapid liver hypertrophy using Associating Liver Partition and Portal vein ligation for a Staged hepatectomy (ALPPS) has been proposed for resection of borderline resectable liver tumors. This model may elucidate mechanisms involved in rapid hypertrophy and allows testing of drugs that promote or block the acceleration of regeneration.

Recent clinical data support an aggressive surgical approach to both primary and metastatic liver tumors. For some indications, like colorectal liver ...

Intrasplenic Transplantation of Hepatocytes After Partial Hepatectomy in NOD.SCID Mice

Partial hepatectomy is a versatile and reproducible method to study liver regeneration and the effect of cell based therapeutics in various pathological conditions. Partial hepatectomy also facilitates the increased engraftment and proliferation of transplanted cells by accelerating neovascularization and cell migration towards the liver. Here, we describe a simple protocol for performing 30% hepatectomy and transplantation of cells in the spleen of a non-obese diabetic/severe combined immunodeficient NOD.SCID (NOD.CB17-Prkdcscid/J) mouse. 
In this procedure, two small incisions are made. The first incision is to expose and resect the left lobe of the liver, and another small incision is made to expose the spleen for the intrasplenic transplantation of cells. This procedure does not require any specialized surgical skills, and it can be completed in 5-7 minutes with less stress and pain, faster recovery, and better survival. We have demonstrated the transplantation of hepatocytes isolated from a green fluorescent protein (GFP) expressing mouse (Transgenic C57BL/6-Tg (UBC-GFP) 30Scha/J), as well as hepatocyte like cells of human origin (NeoHep) in partially hepatectomized NOD.SCID mice.

We have described a protocol for performing partial hepatectomy (PHx) and cell transplantation via spleen in NOD.SCID (NOD.CB17-Prkdcscid/J) mice. In this protocol, an incision is made to expose and resect the left lobe of the liver followed by another incision for the intrasplenic transplantation of cells.

Partial hepatectomy is a versatile and reproducible method to study liver regeneration and the effect of cell based therapeutics in various pathological ...

Blood Collection Through Subclavian Vein Puncture in Mice

The mouse is the foremost mammalian model for studying human disease and human health. However, blood sample collection from mice is challenging in research work. Tail blood collection is a popular method when a small amount of blood sample is needed. Orbital artery could be considered if a large amount of blood is needed but this blood collection method has ethical issues. Formerly, we demonstrated the feasibility and safety of blood sample collection through subclavian vein puncture in rats, and here we investigate whether this method could be used in mice. We report that this method is safe and practical for blood collection in mice. Blood collection through the subclavian vein puncture in mice can be a convenient method in daily research works.

Here, we present a protocol to take blood samples from the subclavian vein of mice.

The mouse is the foremost mammalian model for studying human disease and human health. However, blood sample collection from mice is challenging in ...