newsmakers: A C-Free Mouse
	by Angela Spivey

ll humans need vitamin C. It’s important for growth and healthy bones, teeth, gums, ligaments, and blood vessels. But unlike most animals, humans have to get their vitamin C from food—they can’t produce it on their own.

That’s made it difficult to perform experiments on animals to see what happens when they’re deprived of vitamin C. Until now.

Carolina researchers have developed the world’s first mice incapable of synthesizing vitamin C. These genetically engineered mice should become a valuable tool in determining vitamin C’s role in health and illness, the scientists say.

Nobuyo Maeda, professor of pathology and laboratory medicine, headed the project. She says they were able to generate the mice by inactivating a gene that is a key enzyme in making ascorbic acid—another name for vitamin C. “If the mice don’t receive supplementary ascorbic acid within five weeks, they become anemic, begin to lose weight, and die,” Maeda says.

aeda’s colleague, Oliver Smithies, explains that these “humanized” mice will provide numerous opportunities for systematic studies of the role of antioxidants in health and disease. As levels of vitamin C in the mice’s blood drop, scientists will be able to measure cholesterol levels, as well as note changes in the wall of the aorta, the main artery channeling blood from the heart to the body.

Such experiments will help scientists tell what effects vitamin C deficiency has on genetic vascular diseases, such as atherosclerosis—commonly known as “hardening of the arteries.”

For the past 15 years Smithies and Maeda have concentrated on developing animal models for human genetic illnesses. Smithies is known for creating homologous recombination, a revolutionary gene-targeting technique that allows scientists to engineer mice that mimic a variety of human disorders, such as cystic fibrosis.

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