Inside Our Labs: Christopher Fraker, PhD

Enhanced Technique Improves Evaluation of Islet Cell Transplants

In recent years, there has been significant progress in treating type 1 diabetes using transplants of islet cells and stem cell-derived beta cells. These cells are crucial because they help the body produce insulin, which controls blood sugar. However, one major challenge remains: ensuring that these cells are consistently effective before they are used in patients.

Traditionally, the effectiveness of these cells, often sourced from donated pancreases, has been assessed by measuring how much insulin they produce under different conditions. The current standard involves using bioassay transplant models to see if the human cells will work after they are transplanted. This method is far from perfect because it takes a long time to see results, and those results may not always directly translate to how the cells will perform in humans due to differences in immune responses and other factors.

Recognizing these limitations, researchers are continuously working on developing faster and more reliable tests that can predict how well these cells will function before they are transplanted into patients. Dr. Christopher Fraker, a Research Associate Professor at the Diabetes Research Institute, University of Miami, and his team have introduced an improved testing method. This method, known as static glucose-stimulated insulin secretion (sGSIS), evaluates how effectively islets produce insulin before transplantation by exposing them to different glucose levels and measuring the insulin they produce. This measurement gives a good indication of how quickly the islets can help reverse diabetes after transplantation.

Experimental findings suggest that this method predicts time to reversal more accurately than the previous technique, which used the Stimulation Index to compare insulin production at different glucose concentrations.

In essence, this improved testing technique offers a more dependable method for selecting optimal islets for transplantation, potentially enhancing patient outcomes in diabetes management.

Further Information:

For more detailed information on this innovative research, you can access the full study here .

This new technique promises to enhance the precision and success of islet transplantation, marking a significant stride toward more effective diabetes management.

Figure legend: In this procedure, called the static glucose-stimulated insulin secretion (sGSIS) potency assay, small clusters of cells known as islets are first prepared in a special mixture. They then go through a sequence of steps where they are exposed to different sugar levels: starting with a low sugar level, then a high one, and finally, a low level again. This helps researchers understand how well these islets can produce insulin, the hormone that regulates blood sugar.

The amount of insulin produced by the islets is then measured using a standard lab technique. Based on these measurements, the islets are categorized into two groups: those that are likely to work well in treatment (good) and those that are not (bad).

Next, these islets are tested into bioassay transplant models. The success of each transplant is determined by seeing how quickly it can reverse diabetes in the model. The results help researchers decide if the islets are effective enough to potentially be used in humans to treat diabetes.

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