Groundbreaking movies capture diabetes destruction

Scientists have created the world’s first cellular movies capturing type 1 diabetes destruction of beta cells in mouse models, according to the La Jolla Institute of Allergy & Immunology.

The movies use a new procedure that allows use of a two-photon microscope in the pancreas, a small organ that proved difficult for researchers to access until now.

“These images provide critical information about the disease process, in particular showing us the reasons why the beta cell destruction (underlying type 1 diabetes) occurs very slowly over time,” said George Eisenbarth, MD, PhD, and executive director of the Barbara Davis Center for Childhood Diabetes in Colorado.

The movies depict immune system T cells attacking and destroying insulin-producing beta cells. The immune T cells resemble ants scurrying randomly looking for their prey.

Scientists used the live images to identify the specific blood vessels where the T cells enter the pancreas. They also discovered that the T cells slow down when they find beta cells and release toxic substances that eventually kill them.

Tens of millions of T cells are required to achieve massive beta cell destruction in mice, according to the study. T cells numbers in humans are thought to be significantly lower than in mice.

Scientists also discovered the time sequence of these events. Their calculations found that it takes hours to kill just a few beta cells. This may explain the protracted pre-diabetes stage in type 1 diabetes.

“This means that the autoimmune attack is already ongoing for years before the number of beta cells drops below a critical threshold, resulting in clinical diagnosis,” says Matthias von Herrath, MD, director of the Diabetes Research Center at the La Jolla Institute for Allergy & Immunology in San Diego, California.

Researchers hope that capturing this process real-time will lead to discoveries in the treatment and eventually prevention of type 1 diabetes.

Type 1 diabetes is an autoimmune disorder in which the body’s immune system attacks and destroys beta cells in the pancreas. When beta cells are destroyed, the body does not produce enough of the hormone insulin. As a result, glucose stays in the blood and can cause serious damage to the body’s organ systems.

The movies and a paper on the research study appear online in the Journal of Clinical Investigations. The movies are available for viewing at http://www.jci.org/articles/view/59285.

Source: La Jolla Institute for Allergy & Immunology, Juvenile Diabetes Research Foundation