Physicists and medical researchers for the first time have demonstrated a new technique that non-invasively measures in real time the level of damage to the skin from sun exposure and aging, and initial results suggest that women’s skin ages faster than men’s. Findings appear in the October 1 issue of Optics Letters, a journal of the Optical Society of America.
This new laser-based technique images the fabric of the deeper layers of the skin, combining methods for imaging collagen and elastin, whose degeneration causes the appearance of wrinkles and the progressive loss of skin smoothness. The technique measures relative amounts of collagen and elastin by a single factor, which can be positive or negative, like temperatures. Higher values of the factor correspond to higher collagen content, and to lower elastin content. Previously, each of the imaging techniques had only been tested on tissue extracted from live patients. Last year, Sung-Jan Lin, of National Taiwan University in Taipei, and collaborators, defined the collagen/elastin factor and demonstrated that it gave results consistent with the results of existing lab techniques.
In the new paper, researchers at Friedrich Schiller University, in Jena, Germany, at the Fraunhofer Institute of Biomedical Technology, in St. Ingbert, Germany, and at JenLab GmbH, a Jena-based laser technology company, tested the technique directly on the forearms of 18 patients, measuring the collagen/elastin factor. The team was also able to obtain images of tiny swaths -- one-fifth of a millimeter wide -- of the proteins' fibrous matrices, showing the physical appearance of the dermis, the white lower-layer of skin that gets exposed in deep abrasions.
Large variations appeared from patient to patient, and even from one part of a patient's forearm to another. “In a healthy 35-year-old, some areas can appear like the skin of a 25-year-old, and others like that of someone who's 50,” said Johannes Koehler, a dermatologist at Friedrich Schiller University and a coauthor of the Optics Letters paper. But on average, both the collagen/elastin factor and the physical appearance of the network showed a clear dependence on the patients' age. The dependence appeared to be sex-dependent, with women's skin losing collagen at faster rates than men's.
The two methods combined in the imaging technique use the ability of ultra-brief pulses of laser infrared light to stimulate tissues to emit light at shorter wavelengths -- blue in the case of collagen, and green in the case of elastin. Since the upper layer of the skin, called the epidermis, is virtually transparent to infrared light, the infrared laser can reach the dermis with intense pulses of light without damaging the upper layers. By two different quantum processes, collagen and elastin will then respond by glowing blue and green.
Skin makes a great target for gene therapies and stem cell therapies because it is so much more easily accessible than the rest of the body. Combine the accessibility of skin with the widespread willingness of people to spend large amounts of money to look younger and I predict one of the earlier stem cell therapies will be for rejuvenating the skin and its underlying layers. Plastic surgery is a booming growth injury. When the TV show Dr. 90210 shows the first women to receive stem cell therapy to make their faces look truly young again the stampede for dermal stem cell therapy will be huge.
Skin rejuvenation will provide body-wide benefits. Old skin probably generates free radicals and inflammatory compounds. Make the skin young again and that'll remove one source of oxidative stress on the body.
|Share |||Randall Parker, 2006 October 05 10:22 PM Aging Appearances|