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

Summary

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

Abstract

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.

Introduction

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 groups^1,2,3,4,5. It regained popularity after the breakthrough in human islet transplantation in the yea....

Protocol

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)

1. Recipient mice preparation:
   1. Weigh all mice individually.
   2. Check blood glucose levels from a tail vein blood sample using a glucometer.
2. STZ dose determination for three different scenarios:

Discussion

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 s.......

Materials

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