Genetics and stem cells

Eternal youth… for mice

“Scientists have found a way to reverse the aging process in skin, restoring thinning tissue to a more youthful state”, reported The Guardian on 30 November 2007. Other newspapers picked up the story saying that a single gene has been discovered that could hold the secret to younger looking skin.

As all the newspapers report, the study is a laboratory experiment on mice. The discovery of this gene may be exciting news for the scientific community but there is no current application of the discovery to human ageing. In addition, the gene in question is important elsewhere in the body, so until all the mechanisms are fully understood, it is premature to be heralding the discovery as an elixir to restore youth in humans.

Where did the story come from?

Dr Adam Adler and colleagues from the Stanford University School of Medicine in California and other academic and scientific institutes in the USA carried out this study. The study was funded by grants from the American Cancer Society, the National Institutes of Health, the Israel Science Foundation, the National Cancer Institute, and the California Breast Cancer Research Program. It was published in the peer-reviewed medical journal: Genes & Development .

What kind of scientific study was this?

There were two main parts to the study. First, the researchers identified single genes and groups of genes that appeared to be linked to ageing (that is, their expression increased or decreased with age). They identified these groups of genes in tissue from mice, rats and dogs and in six human tissue types (skin, two types of kidney tissue, abdominal muscle, skeletal muscle, and brain). When they had identified the genes most strongly linked to ageing, they determined which particular protein in the cells controlled the genes’ expression.

The researchers then tested whether this control protein would affect “ageing” of skin cells of older mice. They applied a chemical that blocked the function of the protein to one side of the mice’s bodies. To the other side of the same mouse, they applied a substance that did not block its activity. The tissue on either side of the mice’s bodies was then compared to see what effect the block would have on the skin. The researchers also took DNA samples from the skin on both sides to analyse what was happening at the genetic level. They also compared skin from young mice (1 month old) with skin from the old mice (18–23 months old).

What were the results of the study?

The researchers identified a group of genes that are regulated by a control protein – NF-kB transcription factor – that change with aging across humans and mice. When they compared genes in the skin of young mice with genes in the skin of old mice, they found that there were 414 genes in the old mice that were altered by ageing. Blocking the control protein made 225 of these genes indistinguishable from the genes in the skin of the young mice, that is, made the skin more like young skin.

What interpretations did the researchers draw from these results?

The researchers conclude that preventing the expression of certain genes in mice skin can make it revert to a genetic make-up similar to that of young mice.

What does the NHS Knowledge Service make of this study? 

This study has identified a group of genes linked to ageing across a range of mammalian tissues. It has also identified the transcription factor (control protein) associated with their regulation – NF-kB. Blocking the transcription factor and inhibiting the expression of the group of genes appeared to “rejuvenate” mice skin.

However, the application of this type of treatment to human ageing is unclear. The genes that were blocked in order to make the skin appear younger have other important functions in the mice, such as controlling cell growth. There is no indication from this study of what effects altering the genes had on the long-term health of the mice. The researchers say that their study has highlighted several areas for future study and provides a framework on which scientists can build their knowledge of ageing in humans. Hopes that this discovery will lead to human products or treatments that might prevent or reverse ageing, are premature, and headed for disappointment for the foreseeable future.

Sir Muir Gray adds...

Yet again the future looks bright for mice but for humans the message is not so clear. In the meantime, keep active, avoid the sun and don’t smoke are the messages if you want to keep your skin looking young.

NHS Attribution