cells with peroxide or glucocorticoids or
UV can be useful to screen for anti-aging activity based on antioxidant or
enzyme inhibitory activity, a more realistic approach to senescence study and
slowdown is obtained with longer term
cell culture studies involving proliferation rates, marker proteins and telom-ere analysis.
David Boudier of Silab looked at the
papillary dermis (PD), explaining that
the matrix proteins of the PD are
responsible for the major biomechanical
properties of the skin. Mr. Boudier
explained that deterioration of oxytalan
fibers begins at 30-40 years of age and
gradually disappears under the dermal
epidermal junction. Moreover, the
expression of collagens by papillary
fibroblasts is also impaired.
“Whatever the measured site,” he
said, “skin loses elasticity with age.”
As a result, Silab developed an in-vitro
model of intrinsic aging of the PD to
study expression profiles of different
matrix proteins. Using this in-vitro
model of senescent papillary fibroblasts,
Silab found that a treatment based on a
Cyperus esculentis tuber extract
restores a normal expression profile.
Few topics are hotter than sun care
right now, as the Food and Drug
Administration and the industry debate
the new FDA guidelines for assessing
UVA protection of sunscreens in-vitro.
Olga Dueva-Koganov of Ciba detailed
new in-vitro test conditions for the evaluation of sunscreen UVA protection
that closely follows the requirements
published in the new FDA guidelines.
Dr. Dueva-Koganov’s team used a
Ci65A Xenon Weather-O-Meter with a
Right Light inner/Quartz outer filter
combination from Atlas. According to
the speaker, the device provides an
unparalleled match to natural sunlight.
Using a standard application dose of
2mg/cm2 on Vitro Skin N- 19, test articles, including avobenzone, octocrylene,
homosalate, octisalate, oxybenzone,
octinoxate, bemotrizinol and bisoctri-zole, were applied. A test article containing broad-spectrum actives bisoctri-zole and bemotrizinol (not approved for
use in the U.S.), in conjuction with
avobenzone and octocrylene, achieved
the highest UVA rating.
The session’s final speaker, Gabriele
Vielhaber of Symrise, detailed the benefits of using a novel ex-vivo pig skin
organ culture model (PSOCM) for use
in efficacy and safety testing. Dr.
Vielhaber called the model an ethical,
versatile and economical alternative to
animal testing. PSOCM shows reliable
biological responsiveness for up to 21
days of culture, thus enabling long-term
experiments. It is suitable for testing
the efficacy of a variety of cosmetic
ingredients. So far, results obtained in
assessing skin irritation and skin sensitization are very promising, but Dr.
Vielhaber conceded more validation is
“So far, there is no validated in-vitro
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