P-251

Cytoglobin prolongs immunoisolated beta cell survival

J. Stagner, R. Parthasarathy
Robley Rex Veterans Affairs Medical Center, Louisville, USA

Objective: Isolated pancreatic islets are subject to progressive ischemic cell loss in vitro and prior to revascularization after transplantation. It has been suggested that immuno-isolation may help to provide islets for transplantation across immune barriers. Despite the configuration of extravascular immunoisolation devices, islets remain hypoxic and subject to progressive ischemic cell death, thus it is important to increase islet survival in this promising area of islet transplantation. Cytoglobin (CYGB) is an intracellular oxygen binding protein found in many mammalian cells, including islet beta cells. The objective of this study was to determine whether the over expression of CYGB may improve the survival of immunoisolated islets.

Methods: Islets were isolated by standard methods from Lewis rats. Test islets were transfected with the rat CYGB gene with Fugene6 and rested overnight. Untreated or transfected islets were placed in a polyacrylonitrile-polyvinylchloride hollow fiber 15 mm in length with a molecular weight cut off of 60,000 Daltons. Each fiber contained 1500 islets. Streptozotocin-diabetic Lewis rats received 3000 untreated or transfected islets beneath the hepatic capsule. Fasting blood glucose (FBG) was used as an index of islet survival. The fibers were removed for islet viability testing (Calcien AM/propidium iodide) after 60 days or when FBG increased to 10.5 mM.

Results: Control islets maintained a FBG of 7.8+/-01.5 mM for up to 10 days, all failed by 16 +/- 2 days (FBG 14.9 +/-1.1 mM). Transfected islets maintained a FBG of 5.9+/-0.09 for the 60 day period of study (N=6, P<0.001). Recovered control islets had poor viability with 78 +/- 8% central islet necrosis, while transfected islets were more intact with 56 +/- 6% central islet necrosis (P<0.001).

Conclusions: The over expression of CYGB significantly increased the survival of immunoisolated islets and may be a useful adjunct to this form of islet transplantation.

P-251

Cytoglobin prolongs immunoisolated beta cell survival

J. Stagner, R. Parthasarathy
Robley Rex Veterans Affairs Medical Center, Louisville, USA

Objective: Isolated pancreatic islets are subject to progressive ischemic cell loss in vitro and prior to revascularization after transplantation. It has been suggested that immuno-isolation may help to provide islets for transplantation across immune barriers. Despite the configuration of extravascular immunoisolation devices, islets remain hypoxic and subject to progressive ischemic cell death, thus it is important to increase islet survival in this promising area of islet transplantation. Cytoglobin (CYGB) is an intracellular oxygen binding protein found in many mammalian cells, including islet beta cells. The objective of this study was to determine whether the over expression of CYGB may improve the survival of immunoisolated islets.

Methods: Islets were isolated by standard methods from Lewis rats. Test islets were transfected with the rat CYGB gene with Fugene6 and rested overnight. Untreated or transfected islets were placed in a polyacrylonitrile-polyvinylchloride hollow fiber 15 mm in length with a molecular weight cut off of 60,000 Daltons. Each fiber contained 1500 islets. Streptozotocin-diabetic Lewis rats received 3000 untreated or transfected islets beneath the hepatic capsule. Fasting blood glucose (FBG) was used as an index of islet survival. The fibers were removed for islet viability testing (Calcien AM/propidium iodide) after 60 days or when FBG increased to 10.5 mM.

Results: Control islets maintained a FBG of 7.8+/-01.5 mM for up to 10 days, all failed by 16 +/- 2 days (FBG 14.9 +/-1.1 mM). Transfected islets maintained a FBG of 5.9+/-0.09 for the 60 day period of study (N=6, P<0.001). Recovered control islets had poor viability with 78 +/- 8% central islet necrosis, while transfected islets were more intact with 56 +/- 6% central islet necrosis (P<0.001).

Conclusions: The over expression of CYGB significantly increased the survival of immunoisolated islets and may be a useful adjunct to this form of islet transplantation.