Graham I. Harrison

Matrix metalloproteinase-1 and skin ageing in smokers

Smokers look older than non-smokers of the same age. We have compared the concentrations of mRNA for matrix metalloproteinase 1 (MMP-1) in the buttock skin of smokers and non-smokers with quantitative real-time polymerase chain reactions. MMP-1 degrades collagen, which accounts for at least 70% of the dry weight of dermis. We report significantly more MMP-1 mRNA in the skin of smokers than non-smokers whereas no difference was seen for the tissue inhibitor of metalloproteinases 1 (TIMP-1) or the housekeeping gene GAPDH (glyceraldehyde-3-phosphate dehydrogenase). We suggest that smoking-induced MMP-1 might be important in the skin-ageing effects of tobacco smoking.

Ultraviolet radiation-induced erythema in human skin.

We have evaluated UVR-induced erythema in previously unexposed buttock skin of volunteers of skin types I, II, III, and IV. Studies were done with solar-simulated radiation (SSR), UVB, and UVAI and we determined the just perceptible minimal erythema dose (MED) and, in some cases, quantified erythema with a reflectance device. The results show that there is a trend for increased SSR MED with skin type, with the MED of skin type IV being approximately twice that of skin type I, a smaller difference than one might have expected. However, there is a very considerable overlap of MED between skin types which shows that MED is a very poor indictor of skin type. Quantitative dose-response and time course studies with SSR and UVAI showed broadly similar responses when comparable MED-based exposures were given. We used our data to test the new concept of the standard erythema dose (SED) with two different erythema action spectra, and confirmed that the SED approach works with the different UVR sources that we studied.

Sun behaviour and personal UVR exposure among Europeans on short term holidays

Solar ultraviolet radiation (UVR) is known to be the main cause of skin cancer, the incidence of which is rising with national differences across Europe. With this observation study we aimed to determine the impact of nationality on sun behaviour and personal UVR exposure on sun and ski holidays. 25 Danish and 20 Spanish sun-seekers were observed during a sun holiday in Spain, and 26 Danish and 27 Austrian skiers were observed during a ski holiday in Austria. The participants recorded their location and clothing in diaries. Personal time-logged UVR data were recorded as standard erythema doses (SEDs) by an electronic UVR dosimeter worn on the wrist. Danish sun-seekers were outdoors for significantly longer, received significant higher percentages of ambient UVR, and received greater accumulated UVR doses than Spanish sun-seekers. Danish skiers were also outdoors for significantly longer than Austrian skiers, but the behaviour of the Danish skiers did not result in significantly greater accumulated UVR doses. Both Danish and Spanish sun-seekers and Danish and Austrian skiers received substantial UVR doses. The behaviours influence on the UVR doses received by the Danish participants may indicate an explanation of the higher skin cancer incidence among Scandinavians compared with other European populations.

Children sustain high levels of skin DNA photodamage, with a modest increase of serum 25-hydroxyvitamin D3, after a summer holiday in Northern Europe

Childhood solar ultraviolet radiation (UVR) exposure increases the risk of skin cancer in adulthood, which is associated with mutations caused by UVR‐induced cyclobutane pyrimidine dimers (CPD). Solar UVR is also the main source of vitamin D, essential for healthy bone development in children.

The acute effects of ultraviolet radiation on the blood transcriptome are independent of plasma 25OHD3

ABSTRACT The molecular basis of many health outcomes attributed to solar ultraviolet radiation (UVR) is unknown. We tested the hypothesis that they may originate from transcriptional changes in blood cells. This was determined by assessing the effect of fluorescent solar simulated radiation (FSSR) on the transcriptional profile of peripheral blood pre‐ and 6 h, 24 h and 48 h post‐exposure in nine healthy volunteers. Expression of 20 genes was down‐regulated and one was up‐regulated at 6 h after FSSR. All recovered to baseline expression at 24 h or 48 h. These genes have been associated with immune regulation, cancer and blood pressure; health effects attributed to vitamin D via solar UVR exposure. Plasma 25‐hydroxyvitamin D3 [25OHD3] levels increased over time after FSSR and were maximal at 48 h. The increase was more pronounced in participants with low basal 25OHD3 levels. Mediation analyses suggested that changes in gene expression due to FSSR were independent of 25OHD3 and blood cell subpopulations. HighlightsExposure to UVR induced transient changes in gene expression in blood cells.Affected genes are related to immune regulation, cancer and blood pressure.UVR increased 25OHD3 over time, especially in participants with low baseline levels.The acute effects of UVR on the blood transcriptome are independent of 25OHD3.

Sunscreen applied at ≥ 2mg/cm2 during a sunny holiday prevents erythema; a biomarker of UVR-induced DNA damage and suppression of acquired immunity

Sun protection factor (SPF) is assessed with sunscreen applied at 2 mg cm−2. People typically apply around 0·8 mg cm−2 and use sunscreen daily for holidays. Such use results in erythema, which is a risk factor for skin cancer.