Approach to quantify human dermal skin aging using multiphoton laser scanning microscopy.

Extracellular skin structures in human skin are impaired during intrinsic and extrinsic aging. Assessment of these dermal changes is conducted by subjective clinical evaluation and histological and molecular analysis. We aimed to develop a new parameter for the noninvasive quantitative determination of dermal skin alterations utilizing the high-resolution three-dimensional multiphoton laser scanning microscopy (MPLSM) technique.

Folic acid and creatine improve the firmness of human skin in vivo.

Background: The decrease in firmness is a hallmark of skin aging. Accelerated by chronic sun exposure, fundamental changes occur within the dermal extracellular matrix over the years, mainly impairing the collagenous network.

Aims: Based on the qualitative and quantitative assessment of skin firmness, in vitro and in vivo studies were carried out to elucidate the effects of topical folic acid and creatine to counteract this age-dependent reduction in the amount of collagen.

Assessing the risk of skin damage due to femtosecond laser irradiation.

We irradiated freshly excised skin biopsies with four irradiation regimes usually taken for multiphoton imaging. If there is any skin damaging, it is mainly an effect similar to the damaging effects of UV-irradiation. Using fluorescent antibodies against cyclobutane-pyrimidin-dimers (CPDs) in combination with immuno-fluorescence image analysis we quantitatively compared fs-irradiation effects with UV-irradiation (solar simulator).

Risk estimation of skin damage due to ultrashort pulsed, focused near-infrared laser irradiation at 800 nm.

New imaging techniques using near-infrared (NIR) femtosecond lasers (fs-lasers) in multiphoton laser scanning microscopy (MPLSM) have great potential for in vivo applications, particularly in human skin. However, little is known about possible risks. In order to evaluate the risk, a "biological dosimeter" was used.