title: Exploration of scalp surface lipids reveals squalene peroxide as a potential actor in dandruff condition.
abstract: Dandruff is a common but complex disorder with three major contributing factors: (1) individual predisposition, (2) scalp sebum and (3) Malassezia yeast colonization. To obtain further insights into the role of sebum in dandruff biogenesis, we analyzed scalp lipid species in a cohort of ten dandruff-free (control) and ten dandruff-afflicted volunteers by gas chromatography coupled to mass spectrometry. Lipid peroxidation levels and biochemical markers of oxidative stress were also assessed. Squalene, a major sebum component, was significantly more peroxidized in dandruff-affected scalps, resulting in significantly higher ratios of squalene monohydroperoxide (SQOOH)/squalene. This was observed when comparing dandruff-affected zones of dandruff subjects to both their non-affected zones and control subjects. In addition, other biomarkers such as malondialdehyde indicated that oxidative stress levels were raised on dandruff scalps. Surprisingly, differences regarding either free or bound fatty acids were fairly rare and minor. Certain novel findings, especially squalene peroxidation levels, were then confirmed in a validation cohort of 24 dandruff-affected subjects, by comparing dandruff-affected and non-dandruff zones from the same individuals. As SQOOH can induce both keratinocyte inflammatory responses and hyperproliferation in vitro, we hypothesized that increased SQOOH could be considered as a new etiological dandruff factor via its ability to impair scalp barrier function. Our results also indicated that Malassezia could be a major source of squalene peroxidation on the scalp.
authors: L'OREAL Research and Innovation, Aulnay-sous-Bois, France. rjourdain@rd.loreal.com.
authors: Roland
authors: R
authors: Jourdain
authors: Synelvia SAS, Labège, France.
authors: Alain
authors: A
authors: Moga
authors: L'OREAL Research and Innovation, Aulnay-sous-Bois, France.
authors: Philippe
authors: P
authors: Vingler
authors: L'OREAL Research and Innovation, Aulnay-sous-Bois, France.
authors: Charles
authors: C
authors: El Rawadi
authors: L'OREAL Research and Innovation, Saint-Ouen, France.
authors: Florence
authors: F
authors: Pouradier
authors: L'OREAL Research and Innovation, Aulnay-sous-Bois, France.
authors: Luc
authors: L
authors: Souverain
authors: L'OREAL Research and Innovation, Aulnay-sous-Bois, France.
authors: Philippe
authors: P
authors: Bastien
authors: Synelvia SAS, Labège, France.
authors: Nicolas
authors: N
authors: Amalric
authors: L'OREAL Research and Innovation, Aulnay-sous-Bois, France.
authors: Lionel
authors: L
authors: Breton
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D015331:Cohort Studies; D063807:Dandruff / Q000209:etiology / Q000378:metabolism* / Q000382:microbiology; D005227:Fatty Acids / Q000032:analysis / Q000378:metabolism; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D064368:Healthy Volunteers; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D015227:Lipid Peroxidation; D008290:Malassezia / Q000302:isolation & purification / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000032:analysis / Q000378:metabolism; D008875:Middle Aged; D018384:Oxidative Stress; D012535:Scalp / Q000378:metabolism* / Q000382:microbiology; D012629:Sebum / Q000737:chemistry / Q000378:metabolism*; D013185:Squalene / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism
chemical_list: C002821:2,3-oxidosqualene; D015415:Biomarkers; D005227:Fatty Acids; D008315:Malondialdehyde; D013185:Squalene
keywords: Dandruff scalp; Lipids; Malassezia; Oxidative stress; Sebum; Squalene peroxide