[Nle4-D-Phe7]-alpha-melanocyte-stimulating hormone significantly increased pigmentation and decreased UV damage in fair-skinned Caucasian volunteers.
Epidermal melanin reduces some effects of UV radiation, the major cause of skin cancer. To examine whether induced melanin can provide protection from sunburn injury, 65 subjects completed a trial with the potent synthetic melanotropin, [Nle4-D-Phe7]-alpha-melanocyte-stimulating hormone ([Nle4-D-Phe7]-alpha-MSH) delivered by subcutaneous injection into the abdomen at 0.16 mg/kg for three 10-day cycles over 3 months. Melanin density, measured by reflectance spectroscopy, increased significantly in all [Nle4-D-Phe7]-alpha-MSH-treated subjects. The highest increases were in volunteers with lowest baseline skin melanin levels. In subjects with low minimal erythemal dose (MED) skin type, melanin increased by an average of 41% (from 2.55 to 3.59, P < 0.0001 vs placebo) over eight separate skin sites compared with only 12% (from 4.18 to 4.70, P < 0.0001 vs placebo) in subjects with a high-MED skin type. Epidermal sunburn cells resulting from exposure to 3 MED of UV radiation were reduced by more than 50% after [Nle4-D-Phe7]-alpha-MSH treatment in the volunteers with low baseline MED. Thymine dimer formation was also shown to be reduced by 59% (P = 0.002) in the epidermal basal layer. This study has shown for the first time the potential ability of a synthetic hormone that augments melanin production to provide photoprotection to people who normally burn in direct sunlight.
Barnetson
Ross StC
RS
Department of Dermatology, Royal Prince Alfred Hospital at the University of Sydney, Sydney, Australia. ross.barnetson@email.cs.nsw.gov.au
Ooi
Terry K T
TK
Zhuang
Liqing
L
Halliday
Gary M
GM
Reid
Catherine M
CM
Walker
Patrick C
PC
Humphrey
Stuart M
SM
Kleinig
Michael J
MJ
D000328:Adult; D016588:Anticarcinogenic Agents / Q000008:administration & dosage; D001706:Biopsy; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D011740:Pyrimidine Dimers / Q000378:metabolism; D012880:Skin Pigmentation / Q000187:drug effects* / Q000528:radiation effects; D013471:Sunburn / Q000188:drug therapy / Q000473:pathology / Q000517:prevention & control*; D013473:Sunscreening Agents / Q000008:administration & dosage*; D014466:Ultraviolet Rays / Q000009:adverse effects*; D044465:White People; D000521:alpha-MSH / Q000008:administration & dosage / Q000031:analogs & derivatives*
D016588:Anticarcinogenic Agents; D008543:Melanins; D011740:Pyrimidine Dimers; D013473:Sunscreening Agents; D000521:alpha-MSH; C027756:MSH, 4-Nle-7-Phe-alpha-