Low molecular weight dextran sulfate prevents the instant blood-mediated inflammatory reaction induced by adult porcine islets.
BACKGROUND
One of the main obstacles to clinical islet xenotransplantation is the injurious instant blood-mediated inflammatory reaction (IBMIR) that causes rapid binding of platelets to the islet surface, activation of the coagulation and complement systems, and leukocyte infiltration of the islets when the islets are exposed to blood.


METHODS
This study assesses the effect of low molecular weight dextran sulfate (LMW-DS) on IBMIR induced by porcine islets in an in vitro tubing loop assay using human blood and in an in vivo model using diabetic athymic mice.


RESULTS
In vitro experiments demonstrated that platelet consumption, coagulation, and complement activation were already reduced in the presence of LMW-DS at 0.01 mg/mL, and that at 0.1 mg/mL, LMW-DS prevented IBMIR. Immunohistochemical investigation showed that the leukocyte infiltration was abrogated at the highest dose. In vivo experiments showed that the transplanted pig islets survived for a significantly longer period in recipients treated with LMW-DS, and morphologic examination of transplanted islets showed a reduction in IBMIR analogous to that demonstrated by in vitro studies.


CONCLUSIONS
Given that LMW-DS has been used in clinical studies without serious adverse reactions, it has potential as a drug candidate that can control the strong innate immune response induced by pig islets when transplanted through the portal vein.
Goto
Masafumi
M
Department of Radiology, Oncology and Clinical Immunology, Division of Clinical Immunology, the Rudbeck Laboratory, Uppsala, Sweden. gotokichi@aol.com
Johansson
Helena
H
Maeda
Akira
A
Elgue
Graciela
G
Korsgren
Olle
O
Nilsson
Bo
B
D000367:Age Factors; D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects; D003167:Complement Activation / Q000187:drug effects; D016264:Dextran Sulfate / Q000737:chemistry / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental / Q000276:immunology* / Q000601:surgery*; D005342:Fibrinolysis / Q000187:drug effects; D006085:Graft Survival / Q000187:drug effects; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects*; D007150:Immunohistochemistry; D007515:Islets of Langerhans / Q000473:pathology; D016381:Islets of Langerhans Transplantation / Q000276:immunology*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008970:Molecular Weight; D010952:Plasma Substitutes / Q000737:chemistry / Q000494:pharmacology*; D013552:Swine; D014183:Transplantation, Heterologous
D010952:Plasma Substitutes; D016264:Dextran Sulfate