The Effect Of High SPF Sunscreen Application On Vitamin D
Funder
National Health and Medical Research Council
Funding Amount
$1,175,123.00
Summary
Sunscreen prevents sunburn and skin cancer, and current guidelines are that it should be routinely used when the maximum UV index is forecast to reach at least 3. However, applying sunscreen in laboratory experiments reduces vitamin D production, and there is concern that regular application of high SPF sunscreens might increase the risk of vitamin D deficiency. We propose a randomised controlled trial to determine if adhering to the current guidelines decreases vitamin D.
Sunscreen Immune Protection Factor Prediction Of Inhibition Of Anti-tumour Immunity And Carcinogenesis
Funder
National Health and Medical Research Council
Funding Amount
$186,372.00
Summary
Despite sunscreens having been used in Australia for more than 25 years the incidence of skin cancer continues to increase. This is partly due to the long lag time in developing a skin cancer, so that the current incidence reflects sun exposure patterns of many years ago. However this is also partly due to sunscreens not being as effective at preventing skin cancer as they are at preventing sunburn. The ultraviolet wavelengths found in sunlight are the prime cause of skin cancer. Australians are ....Despite sunscreens having been used in Australia for more than 25 years the incidence of skin cancer continues to increase. This is partly due to the long lag time in developing a skin cancer, so that the current incidence reflects sun exposure patterns of many years ago. However this is also partly due to sunscreens not being as effective at preventing skin cancer as they are at preventing sunburn. The ultraviolet wavelengths found in sunlight are the prime cause of skin cancer. Australians are exposed to high levels of sunlight, and consequently 66% of Australians develop skin cancer throughout their lifetime. For this reason, Australia has been dubbed the Skin Cancer Capital of the World. To reduce the incidence of skin cancer in Australia, it is recommended that individuals use sunscreens. The means of assessing the effectiveness of sunscreens is based on an SPF system, which measures the ability of sunscreens to prevent sunburn (erythema). However sunburn is induced by particular ultraviolet wavelengths, and may not be as important for skin cancer assessment as other damaging effects of sunlight, such as immunosuppression and genetic mutations. Sunscreens should be tested for protection from immunosuppression as well as sunburn, as this would aid the development of better sunscreens. We have developed the technology to measure protection of the immune system, and intend to investigate the usefulness of this new sunscreen test.Read moreRead less
CONTINUING MECHANISTIC STUDIES OF UVA PHOTOIMMUNOPROTECTION
Funder
National Health and Medical Research Council
Funding Amount
$261,113.00
Summary
The UVB portion of sunlight causes sunburn, tanning, skin cancer, and suppresses immune function. Longer wavelength UVA is significantly less damaging, may contribute to photoageing and damage to deeper skin layers, but has been much less well studied. UVB-induced immunosuppression appears to be a prerequisite for skin cancer, and experimental protection from the immunosuppression results also in reduced severity of the long-term skin cancer outcome. We have identified a protective effect by UVA ....The UVB portion of sunlight causes sunburn, tanning, skin cancer, and suppresses immune function. Longer wavelength UVA is significantly less damaging, may contribute to photoageing and damage to deeper skin layers, but has been much less well studied. UVB-induced immunosuppression appears to be a prerequisite for skin cancer, and experimental protection from the immunosuppression results also in reduced severity of the long-term skin cancer outcome. We have identified a protective effect by UVA radiation against UVB-immunosuppression when UVA is administered to mice at non-burning environmentally relevant doses. This was an important and unprecedented finding, and is supported by recent observations also in humans. The aim of the present study is to clarify the mechanisms by which this resistance to UVB-induced immunosuppression is achieved, according to 2 main hypotheses: 1. UVA interferes with the actions of cis-urocanic acid, a natural epidermal UV-photoproduct that appears to initiate the immunosuppression by interacting with histamine. 2. UVA alters the balance of immunological control and thus activates normal antioxidant defences of the skin such as metallothionein and haem oxygenase, which antagonise the apparent oxidative requirement for UVB-immunosuppression. These pathways lead to the prediction that increasing the UVA component of the incident radiation will reduce skin cancer development. Humans typically receive disproportionately large UVA doses sunbathing through a UVB-sunscreen, or in cosmetic sunparlours. The assumption that UVA contributes to UVB skin damage may not be true at moderate UV doses, and a potential for UVA to protect from UVB-suppressed immunity and risk of skin cancer would suggest that broad spectrum sunscreens are contraindicated, and that the UVA effects need to be exploited.Read moreRead less
Determination Of An Action Spectrum For Ultraviolet Radiation-induced Immunosuppression In Humans
Funder
National Health and Medical Research Council
Funding Amount
$213,500.00
Summary
Ultraviolet (UV) radiation causes mutations in the skin which can develop into cancers many years later. The skin's immune system is an important defence that prevents most potentially cancerous cells from developing into skin tumours. UV also suppresses skin immunity, allowing cancer cells to proliferate unchecked. There is also evidence that this UV-induced immunosuppression may have important effects on infectious diseases such as herpes virus, leprosy and tropical ulcers. Sunlight contains U ....Ultraviolet (UV) radiation causes mutations in the skin which can develop into cancers many years later. The skin's immune system is an important defence that prevents most potentially cancerous cells from developing into skin tumours. UV also suppresses skin immunity, allowing cancer cells to proliferate unchecked. There is also evidence that this UV-induced immunosuppression may have important effects on infectious diseases such as herpes virus, leprosy and tropical ulcers. Sunlight contains UVB, which causes sunburn, and UVA. Until recently, UVA was thought to have little effect on skin immunity. We have previously shown that both broadband UVB and UVA are immunosuppressive, even after single exposures equivalent to 8 minutes of sunlight. It is not known which UVA wavelengths are most immunosuppressive. These studies will use a xenon arc solar simulator and a series of interference filters to produce narrow UVB and UVA wavebands. The effects of these wavebands on humans can be studied by deliberately eliciting immune responses to substances which volunteers are already sensitive to. One model of skin immunity in these studies is allergy to nickel (in earrings and costume jewellery), which affects 10% of women. The volunteers' backs are exposed to different UV wavelengths, and then nickel patches are taped to both the UV-exposed areas and adjacent, unexposed areas. By comparing the intensity (redness and thickness) of these nickel reactions, immunosuppression caused by each waveband can be measured. Similarly, the Mantoux reaction (in people vaccinated against tuberculosis) provides another, complementary model of skin immunity. Knowledge of the immune effects of different UV wavelengths (an action spectrum for UV immunosuppression) would improve understanding of skin cancer and enable development of better sunscreens, which currently offer only partial immune protection.Read moreRead less