Question

Case Study – Diabetes Mellitus Mohinder, a 28 year old male, had been diagnosed with diabetes mellitus when he was 12 years old. He started experiencing polydipsia, polyuria and polyphagia and his parents noticed that he was very lethargic and seemed continuously fatigued. They would occasionally detect the sweet, “fruity” smell of acetone on his breath. Their PA informed them that this was a sign of ketoacidosis associated with the diabetes. At the time, high fasting glucose levels and islet cell antibodies (ICA) had been detected in his blood. His doctors had him carry out a regimen to control his fluctuations in blood glucose which included diet, exercise and administration of exogenous insulin. At first he was administering insulin 1-3 times a day as indicated by measuring the glucose concentrations in small blood samples obtained from pricking his finger. When he was 22, he got a small battery-powered infusion pump that continuously infused insulin subcutaneously. Now he is considering an experimental treatment that involves implantation of beta-cells derived from donated pancreases. These cells implant in the liver and produce insulin in response to blood glucose levels.

3. What do the ICA suggest about the etiology of his condition?

4. Why is an insulin infusion pump superior to periodic insulin injections? Why would donated beta-cells be superior to the infusion pump if they can be successfully implanted? (Think about the negative feedback loops for control of blood glucose as you answer this question. How do the concepts of sensitivity, gain and lag time relate to this question?)

5. What are the drawbacks to donated pancreas cells? How might embryonic stem cells be used to avoid these problems?

Answer 1

1. These antibodies are marker of damage to insulin secreting beta cells of pancreas. The presence of these antibodies can be traced before complete damage of beta cells.

2. Insulin pump is equipped with a sensor that detects the level of glucose in body/ blood. In this way, insulin is pumped out as and when required by the body.

Beta cells produce insulin, if successfully transplanted, beta cells offer a regular and natural supply of insulin as compared to insulin pump. The insulin production from beta cells can be turned on and off asp per feed back levels of glucose are raised.

3. The risk of excessive bleeding, clot formation in associate vein, liver infection and chances of getting beta cells rejected by the body (because of foreign cells) are few associated adverse events/ effects.

4. Stem cells (pancreas progenitor cells) develop naturally into normal insulin producing beta cells, and thus, resemble more physiologically with natural beta cells and insulin secretion.