Real-time polymerase chain reaction analysis of a 3895-bp mitochondrial DNA deletion in epithelial swabs and its use as a quantitative marker for sunlight exposure in human skin.
BACKGROUND
The use of mitochondrial DNA (mtDNA) damage as a reliable and highly sensitive biomarker of ultraviolet (UV) radiation exposure in both the dermis and epidermis has now been well developed by our group and others. We have previously identified a 3895-bp mtDNA deletion which occurred more frequently and to a higher level in usually sun-exposed skin as opposed to occasionally sun-exposed skin. This work focused on older-aged individuals and, in particular, perilesional, histologically normal skin biopsies taken from patients with skin cancer.


OBJECTIVE
To develop novel, less-invasive methods of obtaining skin samples (i.e. epidermis) from volunteers covering a much wider age range and larger number of individuals (n = 239).


METHODS
The 3895-bp deletion was quantified by a specific real-time polymerase chain reaction assay in normal human epidermis samples taken from three body sites with differing sun exposure.


RESULTS
The results show a statistical increase of the level of the 3895-bp deletion with increasing sun exposure in the epidermal swabs of human skin (P < 0·001) and with increasing age of the donor in the needle biopsy samples.


CONCLUSIONS
These data suggest that the upper layers of the epidermis are an accessible and reliable site for assessing mtDNA damage caused by UV exposure.
Harbottle
A
A
Mitomics, Medical School (CELS), Newcastle University, Framlington Place, Newcastle Upon Tyne NE1 3DW, UK.
Maki
J
J
Reguly
B
B
Wittock
R
R
Robinson
K
K
Parr
R
R
Birch-Machin
M A
MA
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004272:DNA, Mitochondrial / Q000235:genetics / Q000528:radiation effects*; D005260:Female; D005819:Genetic Markers; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D017384:Sequence Deletion / Q000235:genetics*; D012867:Skin / Q000528:radiation effects*; D013472:Sunlight / Q000009:adverse effects*; D014466:Ultraviolet Rays / Q000009:adverse effects; D055815:Young Adult
D004272:DNA, Mitochondrial; D005819:Genetic Markers