WOBURN, MASS. German researchers have, for the first time, used an innovative, non-invasive laser technique to evaluate levels of collagen and elastin in the skin in real time. The technique could eventually be useful in studying skin diseases involving the collagen structure, such as scleroderma or chronic complications of graft-versus-host disease. In addition, it could be useful in testing the efficacy of anti-aging cosmetic products that are designed to address collagen levels.
The study, published in a recent issue of Optics Letters, used in vivo multiphoton laser tomography to measure two-photon excited autofluorescence (AF), and second harmonic generation (SHG) to examine the extracellular matrix components of collagen and elastin.
Under the ultra-brief pulses of laser infrared light, the tissues are stimulated to emit light at shorter wavelengths – for collagen, the light is blue, and for elastin, it is green.THE FACTOR The novel laser technique to define the collagen/elastin factor was introduced in 2005 by Sung-Jan Lin and colleagues at National Taiwan University in Taipei, who found results that were consistent with previous lab techniques.
Working with Germany-based laser company JenLab GmbH, researchers with Friedrich Schiller University applied Lin's technique directly to the forearms of 18 patients, obtaining tiny swaths of collagen and elastin's fibrous matrices measuring just one-fifth of a millimeter wide.
Substantial variations were found, not only from one patient to another, but from one part of a patient's forearm to another. Some similarities clearly emerged, however, including the fact that the collagen/elastin ratio was dependent upon the patient's age, and women's skin was observed as losing collagen at faster rates than men's (Opt Lett. 2006 Oct 1;31(19):2879-2881).
GENDER ACCELERATOR The researchers speculate that the fluctuating hormone levels in women may explain the more rapid aging that was observed.
"As these differences are most notably present beyond the reproductive phase, a connection to decreasing sex hormone levels in the context of menopause is plausible," they wrote. "This is consistent with numerous studies that have shown anti-aging effects of estrogen and progesterone."
They caution, however that, with such a small study, the findings can only be considered preliminary.
"[The finding on women's skin aging faster] was definitely a surprise, but since the sample is very small and the variance is very high, we tried not to emphasize that finding," Dr. Johannes Koehler, M.D., tells Cosmetic Surgery Times .
"It was a minor finding with a new technique that should not be overestimated, but we are preparing a new study to [further] investigate," said Dr. Koehler, a dermatologist at Friedrich Schiller University and a co-author of the Optics Letters paper.
MATRIX STATE The laser technique holds promise for its ability to give precise measurements of collagen and elastin non-invasively, while previous techniques required extracting tissue from live patients and gave only a qualitative assessment of the state of the matrix.
Importantly, the new method makes it possible to monitor variations in the exact same spot as aging progresses — a process not possible using the previous method.