'Fountain of Youth' discovered in mammary glands

Provided by Liam Mitchel, University of Toronto

The Fountain of Youth has been discovered and its not in Florida as Ponce de Leon claimed. Instead, it was found in the mammary glands of genetically modified mice.

A research team led by Professor Rama Khokha has found that when two factors that control tissue development are removed, you can avoid the impact of aging.

Think of tissue as a building that is constantly under renovation. The contractors would be metalloproteinases, which are constantly working to demolish and reconstruct the tissue. The architects in this case, who are trying to reign in and direct the contractors, are known as tissue inhibitors of metalloproteinases or TIMPs. When the architect and the contractors dont communicate well, a building can fall down. In the case of tissue, the result can be cancer.

To understand how metalloproteinases and TIMPs interact, medical researchers breed mice that have one or more of the four different types of TIMPs removed. Khokhas team examined the different combinations and found that when TIMP1 and TIMP3 were removed, breast tissue remained youthful in aged mice. The results are presented inNature Cell Biology.

In the normal course of aging, your tissue losses its ability to develop and repair as fast as it did when you were young. Thats because stem cells, which are abundant in your youth, decline with the passing of time. The U of T team found that with the TIMP1 and TIMP3 architects missing, the pool of stem cells expanded and remained functional throughout the lifetime of these mice.

Normally you would see these pools of stem cells, which reach their peak at six months in the mice, start to decline. As a result, the mammary glands start to degenerate, which increases the risk of breast cancer occurring, explains Khokha. However, we found that in these particular mice, the stem cells remained consistently high when we measured them at every stage of life.

The team also found that despite large number of stem cells, there was no increased risk of cancer.

Its generally assumed that the presence of a large number of stem cells can lead to an increased cancer risk, says Khokha. However, we found these mice had no greater predisposition to cancer.

The next step in this research is to understand why this is happening. Khokha is also working with her colleagues at Princess Margaret to see how altered tissue remodeling might prevent cancer development or lead to a new therapeutic treatment for patients.

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'Fountain of Youth' discovered in mammary glands