The Effect of Heme oxygenase-1 (HO-1) Up-regulation on Islet Grafts Using Laser Capture Microdissection

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 834-867-Islet Biology
Bench to Bedside
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-861
Yu Bae Ahn*
St. Vincent Hospital, Suwong, South Korea
Although early islet graft survival is essential in the outcome of successful islet transplantation, it is generally assumed that considerable islet loss occurs due to metabolic demand and hypoxic injury by the interruption of vascular connection. HO-1 has been previously known to have antioxidant and anti-inflammatory effects during cellular stress. The aim of this experiment was to investigate whether HO-1 induction by Cobalt protoporphyrin (CoPP) in donor islets could result in protection from apoptosis and improve graft function using laser-capture microdissection (LCM). Islets from Sprague-Dawley were incubated in the presence or absence of 100 uM of CoPP for 6 hrs and transplanted under the kidney capsule of diabetic (streptozocin-induced) nude mice. Graft bearing kidney was retrieved 1 day (D1) and 3 days (D3) after islet transplantation, respectively, and frozen sections were made for LCM to obtain beta cell enriched tissue. RNA was extracted and amplified using T7 polymerase. Real time RT-PCR was used to assess expression of selected genes critical for beta cell function and the stress response. Intraperitoneal glucose tolerance test (IPGTT) and immunostaining was also performed. The HO-1 mRNA expression was significantly increased to 299±16% and 199±86% in CoPP treated group on D1 and D3 respectively. Insulin and PDX-1 mRNA expression showed no significant difference between groups. On D3, superoxide dismutase mRNA expression was increased to 176±19% in CoPP treated group compared to control group. Although fasting plasma glucose did not differ 3 days after transplantation, the most remarkable difference in plasma glucose during IPGTT between two groups was noted at 30 min (148 ± 20 vs. 97 ± 16 mg/dl). TUNEL staining, more specific marker for apoptotic cell death, revealed that treatment with CoPP on D1 significantly decreased the number of TUNEL-positive cells. These data suggest HO-1 up-regulation might protect against oxidative stress induced beta cell death in islet graft and, hence improve the outcome of islet transplantation.

Nothing to Disclose: YBA

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm