Nonhydroxylated 1-O-acylceramides in vernix caseosa

• Published in: Journal of lipid research Vol. 59; no. 11; pp. 2164 - 2173
• Main Authors: Harazim, Eva, Vrkoslav, Vladimír, Buděšínský, Miloš, Harazim, Petr, Svoboda, Martin, Plavka, Richard, Bosáková, Zuzana, Cvačka, Josef
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2018; The American Society for Biochemistry and Molecular Biology; Elsevier
• Subjects: ceramides; Ceramides - metabolism; Chromatography, High Pressure Liquid; Gas Chromatography-Mass Spectrometry; Humans; Infant, Newborn; lipidomics; lipids; Lipids - blood; Magnetic Resonance Spectroscopy; Mass Spectrometry; skin; Skin - metabolism; Spectrometry, Mass, Electrospray Ionization; Vernix Caseosa - metabolism; skin; mass spectrometry; lipids; ceramides; lipidomics
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1194/jlr.M088864

Vernix caseosa, the waxy substance that coats the skin of newborn babies, has an extremely complex lipid composition. We have explored these lipids and identified nonhydroxylated 1-O-acylceramides (1-O-ENSs) as a new class of lipids in vernix caseosa. These ceramides mostly contain saturated C11–C38 ester-linked (1-O) acyls, saturated C12–C39 amide-linked acyls, and C16–C24 sphingoid bases. Because their fatty acyl chains are frequently branched, numerous molecular species were separable and detectable by HPLC/MS: we found more than 2,300 molecular species, 972 of which were structurally characterized. The most abundant 1-O-ENSs contained straight-chain and branched fatty acyls with 20, 22, 24, or 26 carbons in the 1-O position, 24 or 26 carbons in the N position, and sphingosine. The 1-O-ENSs were isolated using multistep TLC and HPLC and they accounted for 1% of the total lipid extract. The molecular species of 1-O-ENSs were separated on a C18 HPLC column using an acetonitrile/propan-2-ol gradient and detected by APCI-MS, and the structures were elucidated by high-resolution and tandem MS. Medium-polarity 1-O-ENSs likely contribute to the cohesiveness and to the waterproofing and moisturizing properties of vernix caseosa.