Designer mouse may help diabetics

MICE with the symptoms of human diabetes have been created by genetic engineers to test new drugs for the growing number of people with the condition.

The 'diabetic mouse', which scientists said was healthy apart from an inability to rid its blood of excess sugar immediately after a meal, was created by the insertion of human insulin genes into its cells.

It overproduces insulin, rendering the hormone ineffective in controlling sugar levels. This results in the mouse mimicking one of the principal symptoms of diabetes - high levels of blood glucose.

The diabetic mouse, engineered for an American biotechnology company, DNX of Princeton, New Jersey, is the latest in a growing list of laboratory animals which imitate the symptoms of human diseases ranging from cystic fibrosis to cancer. Paul Schmidt, chief executive of DNX, will announce details of the mouse at a biotechnology conference in London this week.

The company believes it will be able to sell diabetic mice to pharmaceutical organisations wishing to test new anti-diabetic drugs. If the drugs can reduce glucose levels in the mouse, they might be able to do so in human sufferers.

Type 2 diabetes, which the mouse mimics, usually occurs in middle age and typically results from the body's inability to respond to insulin, perhaps because it has been overproduced for years causing a form of insulin resistance. Such people are generally overweight and their blood sugar levels are unnaturally high. There is at present no effective treatment except to diet, which often proves difficult.

Mr Schmidt said that other attempts at producing diabetic mice for drug testing had failed because the animals were not born with high levels of insulin and so took too long to develop the symptoms of the human disease. The DNX mice produce offspring with the symptoms.

Effective cures for type 2 diabetes have been hampered by the inability to design and test new drugs, he added.

Mark Swanson, scientific director of DNX, denied that such research was immoral. 'Everyone wants to do a minimal amount of animal research. If you had one good model of a human disease, you would probably use fewer animals.'