London, July 1 A genetic analysis of human skin has revealed what makes us look old, say American scientists.

According to scientists, the finding could throw up ways to smooth away wrinkles and provide a quantifiable way to test claims made for skin products, reports New Scientist.

Rosemary Osborne of Procter and Gamble in Cincinnati, Ohio, and colleagues used DNA microarrays, common in the drugs industry, to measure the expression of thousands of genes in skin of different ages.

The researchers compared gene expression in skin samples from the buttocks and forearms of 10 young and 10 older women.

In older skin, they found a decrease in the expression of genes involved in cholesterol and fatty acid synthesis.

The researchers also found that the opposite was true for genes associated with inflammation and other components of the immune system, suggesting that the immune system may play a role in ageing.

Treating the older skin with niacinamide, which helps skin retain moisture, damped down expression of genes related to inflammation.

The researchers say that targeting this inflammation might one day help to keep wrinkles at bay.

The findings appear in the Journal of Drugs in Dermatology. (ANI)