Low-Dose Streptozotocin Induces Sustained Hyperglycemia in Macaca nemestrina

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Abstract
The potential for using macaques to create a nonhuman primate diabetic model was investigated. The significant objectives were to determine a) prognosis of STZ induced permanent beta cell destruction in nonhuman primates, and b) the potential to use STZ treated animals in a model of autoimmune diabetes by following adoptively transferred lymphocytes into MHC identical macaques. Beta cell impairment was achieved by a single intravenous, low dose (1CMH) mg/kg body weight) streptozotocin injection in a majority of pigtailed macaques (Macaco nemestrina). Multiple injections, even at low doses at close intervals affected liver and kidney functions in addition to beta cell destruction. Abnormal IVGTT were observed in all streptozo-tocin-treated animals, in some within a week to 10 days. The fasting blood glucose levels rose from <70 mg/dl in pre-STZ stage to above 400 mg/dl in severely diabetic macaques. Histological evidence suggests loss of beta cells when animals were euthanized within two to four weeks post-STZ treatment. Near complete destruction of beta cells was observed in animals maintained longer than three months on insulin. Donor T cells from STZ-treated animals were incubated overnight with 10U/ml IL-2 and 2.5 ug/ml PHA and then injected iv into a MHC-identical non-diabetic sibling. Three weeks later a second injection of donor PMBC labeled with vital dye Cell Tracker Green was given and the animal was euthanized after 24 hours. The recipient showed labeled donor T cells in the pancreas, spleen and peripheral blood, consistent with specific homing of activated lymphocytes from the diabetic donor.