Geographical ancestry is a key determinant of epidermal morphology and dermal composition.
BACKGROUND
Geographical ancestry plays a key role in determining the susceptibility of human skin to external insults and dermatological disease. Despite this, studies of skin from individuals of diverse geographical ancestry focus primarily on epidermal pigmentation. Few reports characterize the gross morphology and composition of the dermis and dermal-epidermal junction (DEJ).


OBJECTIVE
To characterize epidermal morphology and dermal composition in skin from individuals of diverse geographical ancestry.


METHODS
Immunohistochemical techniques were used to assess epidermal morphology and protein composition of the DEJ and dermal extracellular matrix in photoprotected skin from young African, Eurasian and Far East Asian individuals (n = 7 per group; age 18-30 years).


RESULTS
The epidermis of African skin was thicker, with deeper rete ridges and a more convoluted DEJ than Eurasian and Far East Asian skin. Compared with Eurasians, protein composition of the DEJ was collagen VII poor in African and Far East Asian skin (P < 0·001 and P < 0·01, respectively); the dermis of African skin was enriched in fibrillar collagens (P < 0·05), but was relatively elastin poor (P < 0·05). African dermis was abundant in fibrillin-rich microfibrils and fibulin-5 (P < 0·001 and P < 0·001, respectively) compared with Eurasian and Far East Asian skin.


CONCLUSIONS
We demonstrate that fundamental differences exist in skin structure and composition in individuals of diverse geographical ancestry. Disparate environmental pressures encountered by ancestral human populations living at different latitudes may have driven adaptations in skin structure and composition. Further research into the functional significance and clinical consequences of these differences is warranted.
Centre for Dermatology, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester, Manchester, U.K; The Dermatology Centre, Salford Royal NHS Foundation Trust, Salford, U.K.
A K
AK
Langton
M J
MJ
Sherratt
W I
WI
Sellers
C E M
CE
Griffiths
R E B
RE
Watson
D000293:Adolescent; D000328:Adult; D024141:Collagen Type IV / Q000378:metabolism; D020405:Dermis / Q000033:anatomy & histology / Q000378:metabolism; D004549:Elastin / Q000378:metabolism; D004817:Epidermis / Q000033:anatomy & histology / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D024022:Fibrillar Collagens / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D044469:Racial Groups / Q000208:ethnology*; D012867:Skin / Q000033:anatomy & histology* / Q000378:metabolism; D055815:Young Adult
D024141:Collagen Type IV; D024022:Fibrillar Collagens; D006025:Glycosaminoglycans; D004549:Elastin