Lipid ingredients in moisturizers can modulate skin responses to UV in barrier-disrupted human skin in vivo.
BACKGROUND
Chemicals with a molecular weight <500 and adequate lipid solubility can penetrate the intact human skin. As many lipid ingredients in moisturizers have molecular weights <500, the lipid ingredients may penetrate into the skin and affect skin responses to UV; however, little is known about this phenomenon.


OBJECTIVE
To evaluate the effects of major lipid ingredients in moisturizers on skin responses to UV in tape-stripped human skin in vivo.


METHODS
We evaluated the effects of three major lipid ingredients in moisturizers (cholesterol, linoleic acid, and a synthetic ceramide, N-oleoyl-phytosphingosine) on skin responses to UV in the tape-stripped skin of healthy volunteers. After 2 days of lipid-application, the areas were irradiated with UV, and skin samples were obtained 24h after irradiation. Histologic features and the expression of the markers of collagen metabolism and inflammatory mediators were evaluated.


RESULTS
Compared to vehicle, topical cholesterol significantly decreased the degree of dermal inflammatory infiltrates and exocytosis, and also decreased the expression of MMP-1, IL-6, and IL-1ß mRNA. In contrast, topical linoleic acid increased the induction of apoptotic cells, and the expression of MMP-1 and IL-6 mRNA. N-oleoyl-phytosphingosine increased the expression of MMP-1 and IL-6 mRNA, while decreasing the expression of COX-2 mRNA.


CONCLUSIONS
Topical cholesterol can protect the barrier-disrupted skin against UV-induced damage, while linoleic acid or N-oleoyl-phytosphingosine alone has the potential to aggravate the damage.
Department of Dermatology, Seoul National University College of Medicine, Seoul, Republic of Korea.
Hee Jin
HJ
Byun
Kwang Hyun
KH
Cho
Hee Chul
HC
Eun
Min-Jung
MJ
Lee
Youngae
Y
Lee
Serah
S
Lee
Jin Ho
JH
Chung
D000279:Administration, Cutaneous; D000328:Adult; D016009:Chi-Square Distribution; D002784:Cholesterol / Q000008:administration & dosage; D003094:Collagen / Q000378:metabolism; D003358:Cosmetics / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D053583:Interleukin-1beta / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics; D019787:Linoleic Acid / Q000008:administration & dosage; D008055:Lipids / Q000008:administration & dosage* / Q000009:adverse effects / Q000737:chemistry; D020781:Matrix Metalloproteinase 1 / Q000235:genetics; D008875:Middle Aged; D008970:Molecular Weight; D010539:Permeability; D012333:RNA, Messenger / Q000378:metabolism; D056910:Republic of Korea; D018570:Risk Assessment; D012307:Risk Factors; D012867:Skin / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D012869:Skin Absorption; D013110:Sphingosine / Q000008:administration & dosage / Q000031:analogs & derivatives; D013471:Sunburn / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013997:Time Factors; D014466:Ultraviolet Rays
D003358:Cosmetics; C508600:IL6 protein, human; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D015850:Interleukin-6; D008055:Lipids; D012333:RNA, Messenger; D003094:Collagen; D002784:Cholesterol; D019787:Linoleic Acid; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1; C012491:phytosphingosine; D013110:Sphingosine