It is not just our bodies that become stiff in old age. Skin cells also appear to become more rigid. The discovery might just lead to new ways to rejuvenate skin.
Wrinkles and the leathery feel of old skin are thought to result from changes in the dermis, the deepest layer of skin. This becomes fibrous, making the skin less elastic. But Igor Sokolov’s team at Clarkson University in Potsdam, New York, US, has shown that changes may also be taking place in the epithelial cells above the dermis. “What we have discovered is that the epithelial cells themselves become more rigid with age,” says team member Craig Woodworth.
When the researchers measured rigidity by poking human epithelial cells grown in a dish with the tip of an atomic force microscope, they found that after many generations of cell division, cells were two to 10 times as stiff as “younger” cells. They think the increased rigidity is due to the cells’ cytoskeleton – the internal scaffolding of protein fibres – becoming more dense.
The team expect to find the same changes, which appear in cells over weeks or months, in skin samples from elderly people. And some existing drugs might inhibit the stiffening of the cytoskeleton and perhaps slow the ageing process. The team is already testing skin creams containing low doses of these compounds on mice, and expects results in a few months.
Little is known about ageing mechanisms in epithelial cells even though this is the layer that can be targeted with creams, says Marie-Madeleine Cals-Grierson, an expert in ageing at cosmetics company L’Oréal in Paris, France. “The cellular ageing mechanism described in the article seems quite new,” she says. “We are always interested in the results of clinical trials involving anti-ageing compounds.”