Every wonder why smokers and heavy exercisers have wrinkles?
April 16, 2000
Smoking causes wrinkles by upsetting the body's mechanism
for renewing skin. Dermatologists say the finding confirms the long-held
view that smoking ages skin prematurely. Skin stays healthy and young-looking
because of a fine balance between two processes that are constantly at
The first breaks down old skin while the second makes
new skin. The body breaks down the old skin with enzymes called matrix
metalloproteinases, or MMPs. They chop up the fibers that form collagen -- the
connective tissue that makes up around 80 per cent of normal skin.
Researchers suspected that smoking disrupted the
body's natural process of breaking down old skin and renewing it. To test
their idea, they first made a solution of cigarette smoke by pumping smoke
through a saline solution. Smoke was sucked from cigarettes for two seconds
every minute. Tiny drops of this smoke solution were added to dishes of
human fibroblasts, the skin cells that produce collagen.
After a day in contact with smoke solution, the researchers
tested the skin cells to see how much collagen-degrading MMP they were
making and they found that cells exposed to cigarette smoke had produced
far more MMP than normal skin cells.
They also tested the skin cells to see how much new
collagen they were producing and found that the smoke caused a drop in
the production of fresh collagen by up to 40 per cent. This combined effect
of degrading collagen more rapidly and producing less new collagen is
probably what causes premature skin ageing in smokers. In both cases,
the more concentrated the smoke solution the greater the effect on collagen.
Archives of Dermatological
Research April 2000 292:188