Brain Death Significantly Reduces Isolated Pancreatic Islet Yields and Functionality In Vitro and In Vivo After Transplantation in Rats

Abstract

Although ϳ1 million islets exist in the adult human pancreas, current pancreas preservation and islet isolation techniques recover <50%. Presently, cadaveric donors remain the sole source of pancreatic tissue for transplantation. Brain death is characterized by activation of proinflammatory cytokines and organ injury during preservation and reperfusion. In this study, we assessed the effects of brain death on islet isolation yields and functionality. Brain death was induced in male 250-to 350-g Lewis rats by inflation of a Fogarty catheter placed intracranially. The rats were mechanically ventilated for 2, 4, and 6 h before removal of the pancreas (n ‫؍‬ 6). In controls, the catheter was not inflated (n ‫؍‬ 6). Shortly after brain death induction, a significant increase in serum tumor necrosis factor-␣ (TNF-␣), interleukin (IL)-1␤, and IL-6 was demonstrated in a time-dependent manner. Upregulation of TNF-␣, IL-1␤, and IL-6 mRNA was noted in the pancreas. Brain death donors presented lower insulin release after glucose stimulation assessed by in situ perfusion of the pancreas. Islet recovery was reduced in brain death donors compared with controls (at 6 h 602.3 ؎ 233.4 vs. 1,792.5 ؎ 325.4 islet equivalents, respectively; P < 0.05). Islet viability assessed in dissociated islet cells and in intact cultured islets was reduced in islets recovered from brain death donors, an effect associated with higher nuclear activities of NF-B p50, c-Jun, and ATF-2. Islet functionality evaluated in vitro by static incubation and in vivo after intraportal transplantation in syngeneic streptozotocin-induced diabetic rats was significantly reduced in preparations obtained from brain death donors. In conclusion, brain death significantly reduced islet yields and functionality. These observations may lead to strategies to reduce the effects of brain death on pancreatic islets and improve the results in clinical transplantation.

Effect of Pretransplant Preconditioning by Whole Body Hyperthermia on Islet Graft Survival

“…Detrimental factors such as brain teriorate posttransplant function (10). As a consequence, reduction of hyperthermia not only prevented a signifideath, surgical trauma, or enzymatic pancreas digestion are characterized by the activation of proinflammatory cant upregulation of proapoptotic proteins such as Bax, Fas, or DNA fragmentation factor, but minimized overand proapoptotic mechanisms affecting islet yield and viability (1, 13,24,28). After intraportal transplantation expression of HSP27, HSP70, or HSP90 as well (7,10).…”

The synthetic liver X receptor agonist GW3965 reduces tissue factor production and inflammatory responses in human islets in vitro

“…However, sustained insulin-independence after islet transplantation has been difficult to achieve [1], partly because of a significant loss of islets during brain death, islet isolation, transplantation and revascularisation in the liver [2,3]. Islet apoptosis may be induced by various stress factors such as hypoxia [4] and inflammation [5].…”

THERAPY OF ENDOCRINE DISEASE: Islet transplantation for type 1 diabetes: so close and yet so far away

“…Brain death causes up-regulation of pro-inflammatory cytokines in a time-dependent manner (75), hence islets are subject to different stresses during the pancreas procurement which can induce apoptosis. In the previous decades, several studies have shown that improvements in pancreas procurement, islet isolation and culture techniques result in increasing islet yield and subsequently favorable clinical outcomes.…”