Pinewood VOC emissions protect from oxazolone-induced inflammation and dysbiosis in a mouse model of atopic dermatitis.

Pinewood, increasingly used in construction and interior fittings, emits high amounts of volatile organic compounds (VOCs), which tend to accumulate in indoor air. Whether indoor VOCs affect the development of atopic dermatitis (AD) is a matter of debate. We aimed to evaluate the effects of pinewood VOCs on the development of AD-like inflammatory phenotype and linked microbiome alterations, both hallmarks of AD. An oxazolone-induced mouse model of AD was exposed to three different VOC concentrations emitted by pinewood plates throughout the experiment. The disease course and associated immunological and microbiological changes were evaluated. To validate and translate our results to humans, human keratinocytes were exposed to a synthetic pinewood VOCs mixture in an AD environment. Pinewood emitted mainly terpenes, which at a total concentration of 5 mg/m3 significantly improved oxazolone-induced key AD parameters, such as serum total IgE, transepidermal water loss, barrier gene alteration, inflammation, and dysbiosis. Notably, exposure to pinewood VOCs restored the loss of microbial richness and inhibit Staphylococci expansion characteristic of the oxazolone-induced mouse AD model. Most beneficial effects of pinewood VOCs were dose-dependent. In fact, lower (<3 mg/m3) or higher (>10 mg/m3) pinewood VOC levels maintained only limited beneficial effects, such as preserving the microbiome richness or impeding Staphylococci expansion, respectively. In the human in-vitro model, exposure of keratinocytes grown in an AD environment to a pinewood VOCs mixture reduced the release of inflammatory markers. In conclusion, our results indicate that airborne phytochemicals emitted from pinewood have beneficial effects on an AD-like phenotype and associated dysbiosis. These investigations highlight the effects of terpenes as environmental compounds in the prevention and/or control of atopic skin disease.

Wood emissions and asthma development: Results from an experimental mouse model and a prospective cohort study.

BACKGROUND: Increased use of renewable resources like sustainably produced wood in construction or for all sorts of long-lived products is considered to contribute to reducing society's carbon footprint. However, as a natural, biological material, wood and wood products emit specific volatile organic compounds (VOCs). Therefore, the evaluation of possible health effects due to wood emissions is of major interest. OBJECTIVES: We investigated the effects of an exposure to multiple wood-related VOCs on asthma development. METHODS: A murine asthma model was used to evaluate possible allergic and inflammatory effects on the lung after short- or long-term and perinatal exposure to pinewood or oriented strand board (OSB). In addition, wood-related VOCs were measured within the German prospective mother-child cohort LINA and their joint effect on early wheezing or asthma development in children until the age of 10 was estimated by Bayesian kernel machine regression (BKMR) stratifying also for family history of atopy (FHA). RESULTS: Our experimental data show that neither pinewood nor OSB emissions even at high total VOC levels and a long-lasting exposure period induce significant inflammatory or asthma-promoting effects in sensitized or non-sensitized mice. Moreover, an exposure during the vulnerable time window around birth was also without effect. Consistently, in our mother-child cohort LINA, an exposure to multiple wood-related VOCs during pregnancy or the first year of life was not associated with early wheezing or asthma development in children independent from their FHA. CONCLUSION: Our findings indicate that emissions from wood and wood products at levels commonly occurring in the living environment do not exert adverse effects concerning wheezing or asthma development.