Singlet Oxygen Quantification After Skin Exposure to Ultraviolet A (UVA) Light

Study Overview
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Brief Summary
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The objective of this study is quantification of singlet oxygen species in the skin after exposure to Ultraviolet A (UVA) light

Detailed Description
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Ultraviolet (UV) radiation can lead to skin damage and cancer. Ultraviolet A (UVA) irradiation is 10 to 100 times more abundant in natural sunlight than ultraviolet B (UVB), thus human skin is exposed to more UVA irradiation daily.UVA irradiation is not completely filtered by clothing and it penetrates deeper into the dermis than UVB, potentially causing more damage. It is believed that skin cancer, photo aging, and skin immunomodulation are mediated by the reactive oxygen species (ROS) that are generated in response to UV radiation. Singlet oxygen (1O2) is one type of ROS. The aim of this study is to quantify the level of singlet oxygen generated in the skin after exposure to UVA radiation. Previous studies have used low dose ultraviolet A1(UVA1) irradiation of 20 J/cm2, which mimics exposure to strong sunlight of approximately two hours. This study will use UVA doses equivalent to or less than what humans are exposed to in daily life. Additionally, the aim is to quantify singlet oxygen produced in individuals of various skin types before and after application of sunscreens containing zinc oxide and avobenzone (sun protection factor 30). To our knowledge, there is no method for quantifying singlet oxygen in human skin after exposure to UVA light. This is a novel method that may help the investigators understand further the protective effects of various skin types, as well as sunscreens.

Official Title
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Singlet Oxygen Quantification After Skin Exposure to Ultraviolet A (UVA) Light

Conditions
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Sun Damaged Skin

Intervention / Treatment
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* Drug: Zinc Oxide and Avobenzone


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects aged 18 years and older Exclusion Criteria: Those who are currently smoking or have smoked within the past 3 years. Aspirin use Multivitamins and supplements that contain vitamin E Adults unable to consent Individuals who are not yet adults (infants, children, teenagers) Pregnant women Prisoners

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Zinc Oxide, Avobenzone, No Product<br>Participants have zinc oxide, avobenzone, and no product applied to 3 different spots on the forearm and singlet oxygen is measured after UV exposure. | Drug: Zinc Oxide and Avobenzone<br>* Zinc Oxide is applied to one area of the forearm, Avobenzone is applied to another area of the forearm.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Amount of singlet oxygen generated by the left forearm skin (2 cm^2) after exposure to UVA radiation dose of 0.33 J/cm2 |  | 5 minutes at first visit | 
| Amount of singlet oxygen generated by the left forearm skin (2 cm^2) after exposure to UVA radiation dose of 8.25 J/cm2 |  | 5 minutes at first visit | 
| Amount of singlet oxygen generated by the left forearm skin (2 cm^2) after exposure to UVA radiation dose of 16.5 J/cm2 |  | 5 minutes at first visit | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in singlet oxygen (as measured by singlet oxygen molecule numbers) generated between individuals of different skin Fitzpatrick skin types |  | Within 24 hours | 
| Difference in singlet oxygen (as measured by thymidine dimer %) generated between individuals of different skin Fitzpatrick skin types |  | Within 24 hours | 
| Difference in singlet oxygen generation with avobenzone and zinc oxide sunscreens (sun protection factor 30 and 2mg/cm^2 applied for each) vs control (no sunscreen) after exposure to 444.1millijoules (mJ) /cm2 UVA exposure | Difference in singlet oxygen generation (as measured by thymidine dimer %) with two different sunscreens (zinc oxide and avobenzone, each sun protection factor 30 and 2mg/cm^2 applied) vs control (no sunscreen) after exposure to 444.1mJ/cm2 UVA exposure | Within 24 hours | 
| Difference in singlet oxygen generation with avobenzone and zinc oxide sunscreens (sun protection factor 30 and 2mg/cm^2 applied for each) vs control (no sunscreen) after exposure to 444.1millijoules (mJ) /cm2 UVA exposure | Difference in singlet oxygen generation (as measured by singlet oxygen molecule numbers) with two different sunscreens (zinc oxide and avobenzone, each sun protection factor 30 and 2mg/cm^2 applied) vs control (no sunscreen) after exposure to 444.1mJ/cm2 UVA exposure | Within 24 hours | 
| Change in appearance of skin pigmentation as measured by colorimetry after UVA exposure |  | Within 24 hours |