The primary objective of this study is to evaluate the effects of a novel sunscreen formulation by assessing the extent of ultraviolet radiation (UVR)-induced direct and indirect cellular and DNA damage to human skin, in the presence vs absence of the sunscreen, in a population of healthy adults with fair skin (Fitzpatrick Scale type I, II or III).
Skin cancer is the most commonly diagnosed malignancy in the USA and ultraviolet radiation (UVR) exposure is the major environmental risk factor for skin cancer development. Currently available sunscreens utilize UVR filters that, while absorbing UVR energy, have been shown to induce ROS, resulting in oxidative DNA damage after UVR exposure. Organic sunscreen actives have also been shown to penetrate into the skin, raising direct toxicity, as well as irritant and photoallergic concerns. Further systemic absorption may result in additional health risks such as endocrine disruption. Novel sunscreens that more safely prevent both direct and indirect DNA damage are needed. The study team have produced a bioadhesive nanoparticle (BNP) sunscreen designed to keep organic UVR filters from penetrating into the skin and have incorporated non-toxic natural products into this sunscreen to further safely boost UVR absorbing capacity and reduce oxidative, indirect DNA damage. This study will test the capacity of this sunscreen to prevent direct and indirect cellular and DNA damage in human skin exposed to UVR.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
30
The sunscreen contains bioadhesive nanoparticles (BNP) encapsulating avobenzone and octocrylene plus the non-toxic natural products diosmin, ferulic acid, cytisine and trans-resveratrol.
UV light to the correct sites, and the Multiport 610 solar simulator used to deliver 1 MED UVR to the appropriate subsites.
Yale School of Medicine
New Haven, Connecticut, United States
DNA Damage Level by Cyclobutane Pyrimidine Dimer (CPD) Measurement
Ultraviolet radiation (UVR) exposure are indicative of direct DNA damage. DNA will be prepared and assayed by ELISA for quantification of CPDs. CPDs measured in samples obtained immediately after UVR exposure are indicative of direct DNA damage. DNA from skin biopsies was used to quantify the level of DNA damage, represented by CPD levels detected by enzyme-linked immunosorbent assay (ELISA)
Time frame: 5 minutes after UVR exposure
DNA Damage Level by Cyclobutane Pyrimidine Dimer (CPD) Measurement
Ultraviolet radiation (UVR) exposure are indicative of direct DNA damage. DNA will be prepared and assayed by ELISA for quantification of CPDs. CPDs measured in samples obtained immediately after UVR exposure are indicative of direct DNA damage. DNA from skin biopsies was used to quantify the level of DNA damage, represented by CPD levels detected by enzyme-linked immunosorbent assay (ELISA)
Time frame: 4 hours after UVR exposure
Detectable DNA Strand Breaks
Formalin fixed paraffin embedded skin stained with anti-gH2AX to identify keratinocytes with DNA strand breaks. Indirect, oxidative DNA damage may result in DNA strand breaks that can be visualized by microscopic analysis after staining for gH2AX, which builds up within cells with DNA strand break.
Time frame: 5 minutes after UVR exposure
Number of DNA Strand Breaks
Formalin fixed paraffin embedded skin stained with anti-gH2AX to identify keratinocytes with DNA strand breaks. Indirect, oxidative DNA damage may result in DNA strand breaks that can be visualized by microscopic analysis after staining for gH2AX, which builds up within cells with DNA strand break.
Time frame: 4 hours after UVR exposure
Cellular Damage
Formalin fixed paraffin embedded skin stained with anti-3-nitrotyrosine to identify cellular damage. ROS and high energy triplet state species can result in nitration of tyrosine residues of cellular proteins. This type of damage can be visualized by microscopic visualization of 3-nitrotyrosine.
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Time frame: 5 minutes after UVR exposure
Cellular Damage
Formalin fixed paraffin embedded skin stained with anti-3-nitrotyrosine to identify cellular damage. ROS and high energy triplet state species can result in nitration of tyrosine residues of cellular proteins. This type of damage can be visualized by microscopic visualization of 3-nitrotyrosine.
Time frame: 4 hours after UVR exposure