P-198

Molecularly engineered islet cell clusters for diabetes mellitus treatment

S. Yook¹, J-H. Jeong¹, Y.S. Jung¹, S.W. Hong², B.H. Im¹, J.W. Seo¹, J.B. Park¹, M. Lee³, C-H. Ahn⁴, H.S. Lee⁵, D.Y. Lee³, Y. Byun^2
1 Seoul National University, College of Pharmacy, Seoul, South Korea; ² Seoul National University, WCU Departments of Molecular Medicine and Biopharmaceutical Sciences, and College of Pharmacy, Seoul, South Korea; ³ Hanyang University, Department of Bioengineering, Seoul, South Korea; ⁴ Seoul National University, Research Institute of Advanced Materials, Seoul, South Korea; ⁵ Korea Advanced Institute of Science and Technology, Graduate School of Nanoscience and Technology, Daejeon, South Korea

Objectives: Pancreatic islet transplantation is a promising method for curing diabetes mellitus but the fate of transplanted islets faces many challenges such as a hypoxic condition and aggressive host’s immune reactions. We propose here molecularly engineered PEG-Sp-Ex-4 Islet Cell Clusters (ICC) that can overcome problems posed by transplantation circumstances and host’s immune reactions.

Methods: Freshly isolated rat islets were dissociated into single isle cells using 0.25% Trypsin-EDTA. Then a lentiviral vector containing highly releasable Exendin-4, an insulinotropic protein, was delivered into single islet cells (MOI: 12.5, 5h) to enhance glucose sensitivity and to reduce hypoxia-induced apoptosis following transplantation; thereafter, the cells were reaggregated into small size islet cell clusters (ICC). Then the surface of ICC was modified with biocompatible poly(ethylene glycol)-lipid (C18) for preventing immune reactions. The regimen of PEG-Sp-Ex-4 ICC with low doses of anti-CD154 mAb and tacrolimus could effectively maintain the normal glucose level in diabetic mice.

Results: This molecularly engineered ICC regimen with low dose of immunosuppressive drugs prevented cell death in transplantation site, partly through improving the regulation of glucose metabolism and by preventing hypoxia- and immune response-induced apoptosis.

Conclusions:This convergent method using non-toxic biomaterial and pharmaceutics contribute to the development of a new protocol via protecting newly implanted islets from ischemia and preserving functional islet mass in transplants. Application of this remedy is also potentially far-reaching; one would be to help overcome islet-supply shortage due to the limited availability of pancreas donors and to reduce the immunosuppressant regimens to eliminate their adverse effects.

Keywords: Islet cell clusters (ICC), Exendin-4 (Ex-4), polyethylene glycol (PEG), transplantation, tacrolimus, anti-CD154 mAb

P-198

Molecularly engineered islet cell clusters for diabetes mellitus treatment

S. Yook¹, J-H. Jeong¹, Y.S. Jung¹, S.W. Hong², B.H. Im¹, J.W. Seo¹, J.B. Park¹, M. Lee³, C-H. Ahn⁴, H.S. Lee⁵, D.Y. Lee³, Y. Byun^2
1 Seoul National University, College of Pharmacy, Seoul, South Korea; ² Seoul National University, WCU Departments of Molecular Medicine and Biopharmaceutical Sciences, and College of Pharmacy, Seoul, South Korea; ³ Hanyang University, Department of Bioengineering, Seoul, South Korea; ⁴ Seoul National University, Research Institute of Advanced Materials, Seoul, South Korea; ⁵ Korea Advanced Institute of Science and Technology, Graduate School of Nanoscience and Technology, Daejeon, South Korea

Objectives: Pancreatic islet transplantation is a promising method for curing diabetes mellitus but the fate of transplanted islets faces many challenges such as a hypoxic condition and aggressive host’s immune reactions. We propose here molecularly engineered PEG-Sp-Ex-4 Islet Cell Clusters (ICC) that can overcome problems posed by transplantation circumstances and host’s immune reactions.

Methods: Freshly isolated rat islets were dissociated into single isle cells using 0.25% Trypsin-EDTA. Then a lentiviral vector containing highly releasable Exendin-4, an insulinotropic protein, was delivered into single islet cells (MOI: 12.5, 5h) to enhance glucose sensitivity and to reduce hypoxia-induced apoptosis following transplantation; thereafter, the cells were reaggregated into small size islet cell clusters (ICC). Then the surface of ICC was modified with biocompatible poly(ethylene glycol)-lipid (C18) for preventing immune reactions. The regimen of PEG-Sp-Ex-4 ICC with low doses of anti-CD154 mAb and tacrolimus could effectively maintain the normal glucose level in diabetic mice.

Results: This molecularly engineered ICC regimen with low dose of immunosuppressive drugs prevented cell death in transplantation site, partly through improving the regulation of glucose metabolism and by preventing hypoxia- and immune response-induced apoptosis.

Conclusions:This convergent method using non-toxic biomaterial and pharmaceutics contribute to the development of a new protocol via protecting newly implanted islets from ischemia and preserving functional islet mass in transplants. Application of this remedy is also potentially far-reaching; one would be to help overcome islet-supply shortage due to the limited availability of pancreas donors and to reduce the immunosuppressant regimens to eliminate their adverse effects.

Keywords: Islet cell clusters (ICC), Exendin-4 (Ex-4), polyethylene glycol (PEG), transplantation, tacrolimus, anti-CD154 mAb