P-187

Syngeneic rat portal islet transplantation as a model for evaluation of post-transplant adjuvant anti-inflammatory therapies including intravenously delivered bone marrow derived stromal cells

H.L. Marshall¹, S.C. Campbell¹, S. Van Cruchten², R. Arya¹, S.A. White³, C. Huggins¹, R. Stewart¹, A. Aldibbiat¹, L. Ferguson¹, T. Tree⁴, T. Allsopp⁵, A. Ting⁶, J.A.M. Shaw^1
1 Newcastle University, Newcastle upon Tyne, U.K.; ² Regenesys, Leuven, Belgium; ³ Institute of Transplantation, Freeman Hospital, Newcastle upon Tyne, U.K.; ⁴ King's College London, London, U.K.; ⁵ Pfizer Regenerative Medicine, Cambridge, U.K.; ⁶ Athersys, Inc., Cleveland, USA

Objectives: Accruing clinical islet allograft data indicate that there is a critical islet mass below which initial insulin independence and sustained graft function cannot be achieved. The Beta-score or other metabolic assessments provide a further early predictor of long-term outcome. We hypothesise that a sub-group of patients receiving a marginal islet mass with sub-optimal graft function and ongoing evidence of inflammation may still have a salvageable graft. This group of patients may be ideally suited to receive MultiStem®, a bone-marrow derived stem cell product that is currently in clinical trials. To explore this further we have established a rat-to-rat syngeneic intra-portal islet transplant model.

Methods: Diabetes was induced in Wistar rats by intra-peritoneal streptozotocin injection (60 mg/kg). Hepatic intra-portal vein infusion of syngeneic rat islets was undertaken. Weight was recorded daily. Weekly intra-peritoneal glucose tolerance tests (IPGTT) were performed (2g/kg dextrose). Samples were also taken for serum cytokine analysis to evaluate the inflammatory response.

Results: Irreversible diabetes was confirmed pre-transplantation. Transplantation of 400 IEQ per recipient did not significantly reduce blood glucose values, whereas 1100 IEQ per recipient led to glucose lowering/ restored insulin secretion in selected recipients. 2000 IEQ per recipient led to significantly lower fasting glucose (11±2 mmol/l p<0.01 2hr IPGTT 20.8±8.9 p<0.05) and higher plasma insulin (2hr IPGTT insulin range 37-114 pmol/l p<0.05) in comparison to sham-transplanted control animals (fasting glucose 30±3 mmol/l; 2hr IPGTT 36.2±3.5; 2hr insulin range 6.6-12.8 pmol/l) at 5 days post transplant. Absence of pancreas beta-cell regeneration was confirmed post mortem. Studies of systemic injection of MultiStem^® are ongoing.

Conclusions: An islet mass delivering reproducible primary graft function following syngeneic portal transplant has been determined. Studies investigating the potential for attenuating post-transplant inflammatory response and preventing attrition in graft function through intravenous delivery of human stromal cells are currently underway.

P-187

Syngeneic rat portal islet transplantation as a model for evaluation of post-transplant adjuvant anti-inflammatory therapies including intravenously delivered bone marrow derived stromal cells

H.L. Marshall¹, S.C. Campbell¹, S. Van Cruchten², R. Arya¹, S.A. White³, C. Huggins¹, R. Stewart¹, A. Aldibbiat¹, L. Ferguson¹, T. Tree⁴, T. Allsopp⁵, A. Ting⁶, J.A.M. Shaw^1
1 Newcastle University, Newcastle upon Tyne, U.K.; ² Regenesys, Leuven, Belgium; ³ Institute of Transplantation, Freeman Hospital, Newcastle upon Tyne, U.K.; ⁴ King's College London, London, U.K.; ⁵ Pfizer Regenerative Medicine, Cambridge, U.K.; ⁶ Athersys, Inc., Cleveland, USA

Objectives: Accruing clinical islet allograft data indicate that there is a critical islet mass below which initial insulin independence and sustained graft function cannot be achieved. The Beta-score or other metabolic assessments provide a further early predictor of long-term outcome. We hypothesise that a sub-group of patients receiving a marginal islet mass with sub-optimal graft function and ongoing evidence of inflammation may still have a salvageable graft. This group of patients may be ideally suited to receive MultiStem®, a bone-marrow derived stem cell product that is currently in clinical trials. To explore this further we have established a rat-to-rat syngeneic intra-portal islet transplant model.

Methods: Diabetes was induced in Wistar rats by intra-peritoneal streptozotocin injection (60 mg/kg). Hepatic intra-portal vein infusion of syngeneic rat islets was undertaken. Weight was recorded daily. Weekly intra-peritoneal glucose tolerance tests (IPGTT) were performed (2g/kg dextrose). Samples were also taken for serum cytokine analysis to evaluate the inflammatory response.

Results: Irreversible diabetes was confirmed pre-transplantation. Transplantation of 400 IEQ per recipient did not significantly reduce blood glucose values, whereas 1100 IEQ per recipient led to glucose lowering/ restored insulin secretion in selected recipients. 2000 IEQ per recipient led to significantly lower fasting glucose (11±2 mmol/l p<0.01 2hr IPGTT 20.8±8.9 p<0.05) and higher plasma insulin (2hr IPGTT insulin range 37-114 pmol/l p<0.05) in comparison to sham-transplanted control animals (fasting glucose 30±3 mmol/l; 2hr IPGTT 36.2±3.5; 2hr insulin range 6.6-12.8 pmol/l) at 5 days post transplant. Absence of pancreas beta-cell regeneration was confirmed post mortem. Studies of systemic injection of MultiStem^® are ongoing.

Conclusions: An islet mass delivering reproducible primary graft function following syngeneic portal transplant has been determined. Studies investigating the potential for attenuating post-transplant inflammatory response and preventing attrition in graft function through intravenous delivery of human stromal cells are currently underway.