Antimicrobial effect and penetration of silver from silver garments

Silver shows a good antibacterial property. Thus, there is a growing interest
to develop various silver releasing products, such as clothes, socks and
dressing bandages, which might be useful to prevent unpleasant odour or in
pathological skin conditions associated with increased bacterial growth such as
atopic dermatitis (AD). AD is a frequent skin disorder affecting about 20% of
children and about 5% of adults in Western countries. The major
pathophysiological causes are impaired skin barrier in parallel with an up
regulated immune response towards immediate allergens and a down regulated
immune response towards bacterial and viral infections. As a consequence, these
patients have higher bacterial loads on their skin. Furthermore, pathologic
bacteria dominate the epidermal colonization. Among them, Staphylococcus aureus
species are most frequently found. These bacteria secrete super antigens and
toxins that demolish the already impaired skin barrier. This results in the
clinical manifestation and exacerbation of atopic dermatitis.
Modern treatment of AD aims at the improvement of skin barrier function and
control of bacterial colonization. In particular, the latter is crucial for
prevention of exacerbation and improvement of quality of life. For short-term
intervention antibiotics can be used, however due to the increasing risks of
bacterial resistance, they can only be used occasionally and in short periods.
Hence, in this chronic skin disease with continuous need for bacterial control
broad-acting antiseptics are preferred.
Recently a new silver containing textile has been developed (Silverwear®).
Applying of Silverwear® garments might be useful in inhibiting microbial
growth. Ideally, the release of silver (Ag) from the garments should be limited
to the uppermost layers of the skin and systemic absorption of Ag should be
minimized to avoid toxicity. Thus, to assess the possible health risk data on
percutaneous penetration of silver is needed.

The main objectives of this study are to investigate 1) in vivo dermal
absorption of Ag ions from the Silverwear ® garments in healthy versus atopic
skin, 2) effect of dermal exposure to Silverwear ® garments on release of
inflammatory cytokines in the skin and 3) antimicrobial effect of Silverwear ®
garments.

The study design is a double-blinded, placebo-controlled in vivo study. The
subjects (15 healthy volunteers and 15 AD patients) will wear on their forearms
either Silverwear® or placebo sleeve for 5 days, 8 hours a day. On day 1,3 and
5, the uppermost skin layers will be harvested using tape stripping from the
skin sites exposed to Silverwear® garments and placebo . The tape strips will
be analyzed for the presence of Ag to assess dermal absorption and for the
concentration of several inflammatory mediators (IL-1α, IL-1RA and IL-8) to
assess possible inflammatory effects. Furthermore, systemic absorption of Ag
will be investigated by measuring the concentration of Ag in urine of subjects
which will be taken before the study and after the last day of exposure.
The antimicrobial effect of Silverwear® garments will be investigated by swab
samples of the skin before and after wearing Silverwear® garments for 1, 3 and
5 days. The swab samples will be analyzed for density of Staphylococcus Aureus.

There is no health risk associated with participation in the study.
Participants in the study will experience only minor discomfort. The results of
the study are important because a) they give insight in the antimicrobial
efficacy of the silver garment, which may be a useful alternative for using
antibiotics, and b) they give insight in the utility and safety of using these
kind of garments for people with an impaired skin barrier (e.g. AD patients).