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About me

I work as an Senior Researcher at the Unit of Work Envrionmental Toxicology. My research group is interested in how toxic and allergenic chemicals interact with human skin to cause contact allergy and systemic uptake.We use a multi-analytical and cross-disciplinary research approach to cover different aspects of the adverse outcome pathway, from exposure to effect. This approach is unique and not used by other groups in this combination. Based on relevant conditions of occupational and consumer exposure levels, we study allergenic and toxic metals, but also polycyclic aromatic hydrocarbons (PAH) are of interest due to their carcinogenic properties. The research is focused around 5 important topics.

Education

2000 Master of Science in Biology, Stockholm University, Sweden.

Title: Bioaccumulation and elimination of flame retardant PBDE-47 in the Baltic tellenid clam, Macoma Baltica.

2005 PhD in Environmental Science, Örebro University, Sweden.

Title: Exposure to brominated flame retardants in electronics recycling - air and human plasma levels. 

2014 Associate Professor of Occupational and Envrionmental Medicine

2016 Research Group Leader at IMM, KI

Research description

Exposure characterisation

The physical and chemical properties of a substance influence the exposure of skin to chemicals, but also factors such as dose, frequency, occlusion and duration are of importance to take into consideration. The exposure to skin is often of a combined and repeated low-dose character, and can either be intentional as when using a product, accidental (contamination) or involve processes less obvious as airborne deposition and direct contact from holding/using items. The relative significance of such exposures for local and systemic effects is not well understood.

My research group are currently focusing on how the skin physiological condition affects measurements of surface skin doses of chemicals. In our previous studies using defined doses of metals on skin, large variations between measured skin doses in volunteers is often found. We hypothesize that this has to do with the dryness of skin. By combining different techniques to measure skin hydration, such as transepidermal water loss (TEWL) which monitors the passive water evaporation from the skin surface into the air and reflects permeability of the stratum corneum (SC), with electrical impedance as a measure of the barrier properties of the SC which provide insight in the permeation of charged and polar molecules, we will gain better understanding of how skin affects metal deposition on skin and skin sampling. 

Skin condition

The condition at the surface of the skin is affected both by external factors (temperature, humidity, pH, etc) and host-related factors (genetic predisposition, atopy, mutations of the filaggrin gene FLG). The physiological condition of skin influences the uptake of chemicals as well as consequent adverse outcomes but is rarely characterised in research within the field of occupational and environmental dermatology or toxicology. Genetic predisposition for skin disease such as atopy and contact allergy has received much focus lately. How it relates to uptake of hazardous chemicals is not well studied. 

My research group are currently focusing on how the skin physiological condition affects measurements of surface skin doses of chemicals. In our previous studies using defined doses of metals on skin, large variations between measured skin doses in volunteers is often found. We hypothesize that this has to do with the dryness of skin. By combining different techniques to measure skin hydration, such as transepidermal water loss (TEWL) which monitors the passive water evaporation from the skin surface into the air and reflects permeability of the stratum corneum (SC), with electrical impedance as a measure of the barrier properties of the SC which provide insight in the permeation of charged and polar molecules, we will gain better understanding of how skin affects metal deposition on skin and skin sampling. 

Chemical/skin interaction

Local accumulation or systemic absorption of metals and other chemicals may cause negative health effects. Currently there is a lack of essential knowledge concerning, in particular, the uptake of metals through skin under different exposure conditions.

My research group is launching a new project to investigate how the uptake of individual metals through skin is affected by concurrent exposure to several metals. By using diffusion cells we can study the penetration of substances into and through skin. By coupling the diffusion cell directly with a metal analysis instrument (ICP-MS) we will be able to monitor metal concentrations in the receptor fluid on the inside of skin continuously. The concentration can also be monitored in the artificial sweat solution on the outside of the skin. This experimental approach combines two well-established experimental techniques, diffusion cells and ICP-MS, to a novel and unique approach for real-time monitoring of metal uptake through skin.

The amount of a substance still present in the skin after diffusion cell experiments may act as a reservoir. If metals are trapped within skin they may have a longer time frame to interact with the immune system, causing metal allergy. There is surprisingly little information on this reservoir skin dose regarding metals published in the literature. We aim to study this in more detail, to find out how quickly the dose in skin will diminish.

Local effect

The clinical golden standard for diagnosis and evaluation of contact allergy is patch-testing. By applying known concentrations of substances in small aluminium chambers taped to the back of a research person for 48 hours, the response can be evaluated after 3 to 7 days. Patch-tests can also be performed with metal discs made of different alloys that are suspected to give rise to an allergic response. If performed in controls, the tests may give an indication on early immunological response in the skin, which is not visible to the naked eye, by taking skin punch biopsies at the test site. 

My research group collaborates with Lund University, to test already contact allergic individuals with different metal materials, to try to find out if the reactions is stronger or weaker depending on the physicla shape of the material. By taking skin punch-biopsies we may look into the immunological parameters to detect differences that are not visible to the naked eye of the dermatologists. 

Systemic dose

The systemic effect of toxic metals and PAH’s are often connected to carcinogenicity or as in the case of lead related to developmental and reproductive toxicity, but also for adults to hypertension and cardiovascular effects in occupationally exposed workers. It is therefore important to evaluate all exposure routes, and not only oral and inhalation, which has mostly been done in occupational medicine previously.

My research group is currently working with systemic dose measurements of lead, cobalt, nickel and chromium in workers. We use the concentration of these metals in the blood and in the urine as biomarkers of exposure. By concomitantly collect these samples as well as skin dose measurements and air sampling we are establishing a relationship between skin exposure and skin exposure. 

Summary

By performing research an all levels of relevance for skin exposure to harmful chemicals, we can tie skin exposure to systemic doses and allergenic response in the skin, and also provide a mechanistic explanation for what happens with the chemicals once they end up on skin. Occupational skin diseases represent up to 30% of occupational diseases in Europe. European Agency for Safety and Health at Work (EU-OSHA) has stated that skin disorders are the second most common occupational diseases in the EU, with chemicals being responsible for 80–90% of these (EU OSHA 2013), to a cost of 5000 million Euro/year in EU. It is therefore of high relevance to understand factors governing skin exposure, local effects and systemic effects to reduce this societal burden. 

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