Background: Zinc (Zn) is related to insulin synthesis, storage and secretion. Zn status in patients with Type 1 diabetes is significantly lower than in healthy controls. Intraportal islet transplantation (IPIT) is a radical treatment for diabetes, the success of which depends largely on the survival of the transplanted islets. This study demonstrates the impact of a Zn-rich environment on transplanted islet survival.
Material/methods: Diabetic Wistar rats were transplanted with syngeneic islets. Rats in the high-Zn-diet group were fed a standard pelleted diet containing ZnSO4 at 1000 ppm, whereas those in the control group were fed an ordinary diet alone (ZnSO4 at 50 ppm) for two weeks prior to islet transplantation. We examined Zn level of plasma, the blood glucose levels, and histological findings, etc., after intraportal islet transplantation.
Results: The high-Zn-diet group showed excellent blood glucose control compared with the control group on observation days 3, (237.1±120.6 mg/dl vs. 164.2±69.1 mg/dl; p<0.05) and 14, (273.7±160.9 mg/dl vs. 179.2±114.3 mg/dl; p<0.05). Early graft failure was found to be suppressed in the high-Zn-diet group on day 3 after transplantation (6.7% vs. 33.3%: p<0.05). As for the percentage of granulated islets, the high-Zn-diet group was improved (65.1% vs. 41.8%: p<0.05).
Conclusions: These results indicated that a zinc-rich environment is advantageous for the recipient in intraportal islet transplantation. Zn is harmless in humans; thus, we consider that Zn supplementation could be a simple way to improve clinical results of intraportal islet transplantation.