Diabetes, April 2007

Type I Diabetes and Oral Insulin Study Underway

Researchers have begun a clinical study of oral insulin to prevent or delay type 1 diabetes in at-risk persons, according to scientists at the National Institutes of Health (NIH).

The new study is underway in more than 100 medical centers across the US, Canada, Europe, and Australia.

Type 1 Diabetes TrialNet, an NIH -funded network of researchers dedicated to the understanding, prevention, and early treatment of type 1 diabetes, is conducting the research.

“Our goal is to prevent type 1 diabetes or to delay it as long as possible,” says TrialNet study chair Dr. Jay Skyler, of the University of Miami.

“If diabetes can be delayed, even for several years, those at risk will be spared the difficult challenges of controlling glucose and the development of complications for that much longer,” says Dr. Skyler.

Regular Insulin Injections a Challenge

About 5 percent to 10 percent of the nearly 21 million people with diabetes have type 1, formerly known as juvenile onset diabetes or insulin-dependent diabetes.

Type 1 diabetes tends to occur in children and young adults but is also diagnosed in older persons.

People with type 1 diabetes need three or more insulin injections a day or treatment with an insulin pump to maintain blood glucose control.

To prevent complications, they must regularly monitor their blood glucose, striving for a range that is as close to normal as possible.

The constant challenge of managing the disease poses an enormous burden on people with type 1 diabetes and their families.

In the study, researchers are testing whether an insulin capsule taken by mouth once a day can prevent or delay diabetes in a specific group of people at risk for type 1 diabetes.

An earlier trial suggested that oral insulin might delay type 1 diabetes for about four years in some people with autoantibodies to insulin in their blood. Animal studies have also suggested that insulin taken orally may prevent type 1 diabetes.

Some scientists think that introducing insulin via the digestive tract induces tolerance, or a quieting of the immune system.

Insulin taken orally has no side effects because the digestive system breaks it down quickly. To lower blood glucose, insulin must be injected or administered by an insulin pump.

In type 1 diabetes, a person’s own immune cells destroy the beta cells of the pancreas. Beta cells sense blood glucose and produce the hormone insulin, which regulates glucose and converts it to energy.

The immune attack on beta cells begins well before a person develops diabetes and continues long after the disease is diagnosed.

In the early stages of autoimmunity, up to 10 years before diabetes is diagnosed, autoantibodies may appear in the blood.

These autoantibodies to glutamate decarboxylase (GAD), IA-2, and to insulin itself indicate a greater risk for developing type 1 diabetes.

For a person with high-risk genes and all three antibodies, the risk of developing diabetes in the next five years is greater than 50 percent.

Blood Test Looks at Autoantibodies

First- and second-degree relatives of people with type 1 diabetes who may be at risk are being screened through TrialNet’s natural history study, which is examining the immune and metabolic events that precede diabetes symptoms.

Screening involves a simple blood test for the autoantibodies that signify diabetes risk.

Individuals enrolled in the natural history study are closely monitored for diabetes development and may be eligible to participate in the oral insulin trial or future studies that try to arrest the autoimmune process.

TrialNet studies are also aimed at safely preserving insulin production in people recently diagnosed with type 1 diabetes.

In the few months after diagnosis, most patients still have a supply of functioning beta cells that, with the help of insulin injections, contribute to good control of blood glucose.

If beta cells can be protected, more patients would be able to tightly control their blood glucose, which prevents or delays damage to the eyes, nerves, kidneys, heart, and blood vessels.

Always consult your physician for more information.

Online Resources

(These links are provided for the education and convenience of our Neighbors. AAMC is not responsible for the content of Internet sites.)

American Association of Clinical Endocrinologists

American Diabetes Association

American Dietetic Association

Centers for Disease Control and Prevention (CDC)

Everyday Choices, ADA, AHA, and ACS

National Diabetes Education Program

National Diabetes Information Clearinghouse

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

National Institutes of Health (NIH)

Type 1 Diabetes TrialNet

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Type I Diabetes Defined

Type 1 diabetes may also be known by a variety of other names, including the following:

• insulin-dependent diabetes mellitus (IDDM)
• juvenile diabetes
• brittle diabetes
• sugar diabetes

There are two forms of type 1 diabetes:

• idiopathic type 1 diabetes - refers to rare forms of the disease with no known cause.
• immune-mediated diabetes - an autoimmune disorder in which the body's immune system destroys, or attempts to destroy, the cells in the pancreas that produce insulin.

Immune-mediated diabetes is the most common form of type 1 diabetes, and the one generally referred to as type 1 diabetes. The information following refers to this form of type 1 diabetes.

Type 1 diabetes accounts for 5 percent to 10 percent of all diagnosed cases of diabetes in the US.

Type 1 diabetes usually develops in children or young adults, but can start at any age.

The cause of type 1 diabetes is unknown, but it is believed that genetic and environmental factors (possibly viruses) may be involved.

The body's immune system attacks and destroys the insulin producing cells in the pancreas. Insulin allows glucose to enter the cells of the body to provide energy.

When glucose cannot enter the cells, it builds up in the blood and the body's cells literally starve to death.

People with type 1 diabetes must take daily insulin injections and regularly monitor their blood sugar levels.

Type 1 diabetes often appears suddenly.

The following are the most common symptoms of type 1 diabetes. However, each individual may experience symptoms differently. Symptoms may include:

• high levels of sugar in the blood when tested
• high levels of sugar in the urine when tested
• unusual thirst
• frequent urination
• extreme hunger but loss of weight
• blurred vision
• nausea and vomiting
• extreme weakness and fatigue
• irritability and mood changes

In children, symptoms may be similar to those of having the flu.

The symptoms of type 1 diabetes may resemble other conditions or medical problems. Always consult your physician for a diagnosis.