Women's skin sags earlier
Women's skin ages faster than men's. This was the result of studies by scientists led by Martin Kaatz from the University of Jena using a new, non-invasive method.
Kaatz's team used two-photon tomography to determine the proportion of the two fibrous proteins collagen and elastin in the skin of the forearms of 18 patients of all ages. The ratio of collagen to elastin allows conclusions to be drawn about the biological age of the skin, with which the amount of collagen decreases and the proportion of elastin increases. Judging by the results of the seven female test subjects, their collagen percentage decreases faster with age than the males.
In the procedure, scientists used the fact that laser light in the near infrared range is harmless to the skin and penetrates deep into the tissue. Two different mechanisms are used to determine the collagen and elastin content: if two photons of the relatively low-energy infrared light hit an elastin molecule at the same time, the elastin molecule can absorb the photons. The energy thus absorbed is sufficient to excite the elastin to emit higher-energy green fluorescent light.
Collagen molecules have different optical properties, and when struck by two photons of infrared light, they can combine, creating a double-energy photon - in this case, visible blue light. Kaatz and his colleagues can thus measure green and blue light components and obtain images of the fiber protein networks with a diameter of a fifth of a millimeter without having to take skin samples.
Skin cells secrete collagen and elastin into the intercellular spaces to keep skin firm and supple. The less collagen the skin has, the more wrinkled and shapeless it appears.
