Providing Diabetics With Better Options
For Healthier Living

NEW YORK - Ongoing research by chemical engineers and others may soon provide an insulin-dependent diabetic's best chance to lead a normal life: an artificial pancreas. There are believed to be at least 16 million American alone who have some form of diabetes - a disease that affects the pancreas' ability to manufacture insulin, the hormone that regulates the amount of glucose used by the body.

Artificial organ research is not new for chemical engineers, who study such things as membrane porosity and the movement of liquids. In fact, it was chemical engineers who were in large part responsible for development of the artificial kidney - leading to the commonly known therapy of hemodialysis.

Although physicians at several American medical centers have already implanted bio-artificial pancreases in a handful of selected patients, chemical engineers like Carlos A. Ramirez, a professor at the University of Puerto Rico, Mayag FCez, stress that it will be several years before the technology can be perfected for more wide-spread use. At present, he and his colleagues are working on ways to optimize the insulin-secreting dynamics of these hybrid artificial pancreas devices.

The islets of Langerhans, which contain the cells in the pancreas responsible for manufacturing insulin, are the heart of the bio-artificial pancreas. Cells used for the hybrid pancreases are removed from pigs or cattle, encapsulated in special materials, and grown in small chambers, which can be inserted in the human body, either intravascularly or intraperitonedly. Periodically, the chambers may need to be re-supplied with new islet cells, as the original cells either die or slow down in the production of insulin. Researchers underscore that due to the potential for the body's rejection of these cells, only insulin-dependent diabetics already receiving immunosuppresent drugs for other serious conditions, such as kidney transplants, can be considered for implantation of such devices at this time. One of the major challenges ahead is to design a device containing membranes that provide complete immunological protection of the donor pancreatic tissue.

Pump for Success

Insulin delivery pumps, which have much simpler designs than the hybrid artificial pancreas devices, are helping some insulin-dependent diabetics lead more normal lives now. Much of the preliminary work for the development and commercialization of these devices was performed by chemical engineers. These battery-operated devices, usually the size of a pager or beeper, can be programmed to deliver insulin on demand. Typically, they are kept in one's pocket or attached to the belt loop of trousers or a skirt. These pump systems are commonly known as the open-loop type.

Chemical engineers and other researchers are working on the next logical step in this insulin delivery system: "smarter" pumps that can be implanted in the abdomen and "go to work" on their own. Basically, these devices, which have yet to receive FDA approval, have a sensor that detects changing levels of glucose and "tells" the insulin pump - which has a three-month's supply of insulin - when and how much insulin to secrete. Instead of a sudden jolt of insulin delivered by a syringe, the pump supplies a constant, measured stream of insulin through a tube to a tiny needle inserted under the patient's skin. Researchers emphasize that newer systems, which could be implanted in the body and do not require the use of a needle at the skin's surface, may be unavailable for several years.

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