Islet Size May Affect Diabetes Transplant Outcome

In vitro and in vivo studies suggest that small islets are superior to large islets

THURSDAY, March 15 (HealthDay News) -- Small islets produce more insulin and are more likely to survive than large islets, suggesting that islet size is an important factor in determining outcome in type 1 diabetics undergoing human islet transplantation, according to a report published in the March issue of Diabetes.

In a laboratory setting designed to simulate the transplant environment, Roger Lehmann, M.D., of University Hospital Zurich in Switzerland, and colleagues used pancreata from 30 brain-dead donors to assess insulin secretion of large and small islets, and quantify cell death during hypoxic conditions. In the clinical setting, they studied the effect of transplanted islet size on insulin production in seven patients with type 1 diabetes.

The researchers' laboratory experiments showed that small islets produced more insulin than large islets and had a higher survival rate during both normoxic and hypoxic culture. They found that islet volume decreased to 25 percent after 48 hours of hypoxic culture because of a disproportionate loss of large islets. In the clinical setting, the researchers found that islet number was more reliable than islet volume at predicting the stimulated C-peptide response.

"Implementation of our findings might result in higher survival rate of islets, achievement of better islet transplantation outcomes, and economic savings by increasing the percentage of transplantable islet isolations," the authors conclude.

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