Lipid membrane remodeling belongs to the most fundamental processes in the body. The skin barrier lipids, which are ceramide dominant and highly rigid, must attain an unusual multilamellar nanostructure with long periodicity to restrict water loss and prevent the entry of potentially harmful environmental factors. Our data suggest that the skin acid mantle, apart from regulating enzyme activities and keeping away pathogens, may also be a prerequisite for the multilamellar assembly of the skin barrier lipids. Atomic force microscopy on monolayers composed of synthetic or human stratum corneum lipids showed multilayer formation (approximately 10-nm step height) in an acidic but not in a neutral environment. X-ray diffraction, Fourier transform infrared spectroscopy, and permeability studies showed markedly altered lipid nanostructure and increased water loss at neutral pH compared with that at acidic pH. These findings are consistent with the data on the altered organization of skin lipids and increased transepidermal water loss under conditions such as inadequate skin acidification, for example, in neonates, the elderly, and patients with atopic dermatitis.
- MeSH
- atopická dermatitida patologie MeSH
- ceramidy chemie metabolismus MeSH
- cholesterol chemie metabolismus MeSH
- difrakce rentgenového záření MeSH
- epidermis chemie metabolismus patologie MeSH
- koncentrace vodíkových iontů MeSH
- kyseliny mastné neesterifikované chemie metabolismus MeSH
- lidé MeSH
- mastné kyseliny MeSH
- mikroskopie atomárních sil MeSH
- novorozenec MeSH
- permeabilita MeSH
- perspiratio insensibilis * MeSH
- senioři MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- věkové faktory MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Enantiomers of triacylglycerols (TAGs) containing any combination of very long chain fatty acids (VLCFAs) and/or very long chain polyunsaturated fatty acids (VLCPUFAs) with diolein, dilinolein and didocosahexaenoin were synthesized. Gradient non-aqueous reversed-phase high-performance liquid chromatography/high resolution atmospheric pressure chemical ionization-tandem mass spectrometry (NARP-HPLC/HRMS2-APCI) and chiral liquid chromatography were used for the separation and identification of molecular species of these TAGs. Further, NARP-LC and chiral LC were used to separate natural mixtures of TAGs obtained from four natural sources, i.e. ximenia oil (Ximenia americana), green alga (Botryococcus braunii), breweŕs yeast (Saccharomyces pastorianus) and a dinoflagellate (Amphidinium carterae). The ratio of regioisomers and enantiomers in individual samples was determined and a hypothesis has been confirmed on the biosynthetic pathway of natural TAGs, which is based on the preferential representation of VLCFAs and VLCPUFAs in the sn-1 position of the glycerol backbone.
- MeSH
- atmosférický tlak MeSH
- Chlorophyta chemie metabolismus MeSH
- chromatografie s reverzní fází MeSH
- Dinoflagellata chemie metabolismus MeSH
- kyseliny mastné neesterifikované chemie MeSH
- nenasycené mastné kyseliny chemie MeSH
- Saccharomyces chemie metabolismus MeSH
- stereoizomerie MeSH
- tandemová hmotnostní spektrometrie MeSH
- triglyceridy analýza chemie izolace a purifikace MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
The conversion of sphingomyelin (SM) to a ceramide (Cer) by acid sphingomyelinase (aSMase) is an important event in skin barrier development. A deficiency in aSMase in diseases such as Niemann-Pick disease and atopic dermatitis coincides with impaired skin barrier recovery after disruption. We studied how an increased SM/Cer ratio influences the barrier function and microstructure of model stratum corneum (SC) lipid membranes. In the membranes composed of isolated human SC Cer (hCer)/cholesterol/free fatty acids/cholesteryl sulfate, partial or full replacement of hCer by SM increased water loss. Partial replacement of 25% and 50% of hCer by SM also increased the membrane permeability to theophylline and alternating electric current, while a higher SM content either did not alter or even decreased the membrane permeability. In contrast, in a simple membrane model with only one type of Cer (nonhydroxyacyl sphingosine, CerNS), an increased SM/Cer ratio provided a similar or better barrier against the permeation of various markers. X-ray powder diffraction revealed that the replacement of hCer by SM interferes with the formation of the long periodicity lamellar phase with a repeat distance of d=12.7nm. Our results suggest that SM-to-Cer processing in the human epidermis is essential for preventing excessive water loss, while the permeability barrier to exogenous compounds is less sensitive to the presence of sphingomyelin.
- MeSH
- ceramidy metabolismus MeSH
- cholesterol chemie metabolismus MeSH
- difrakce rentgenového záření MeSH
- epidermis metabolismus MeSH
- kůže chemie metabolismus MeSH
- kyseliny mastné neesterifikované chemie metabolismus MeSH
- lidé MeSH
- lipidové dvojvrstvy metabolismus MeSH
- membránové lipidy chemie MeSH
- permeabilita buněčné membrány MeSH
- sfingomyeliny metabolismus MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- biologické markery analýza chemie metabolismus MeSH
- cholin krev MeSH
- diagnostické techniky kardiovaskulární klasifikace normy MeSH
- finanční podpora výzkumu jako téma MeSH
- glykogenfosforylasa chemie MeSH
- kyseliny mastné neesterifikované chemie MeSH
- lidé MeSH
- ligandy MeSH
- nekróza diagnóza etiologie metabolismus MeSH
- sérový albumin chemie MeSH
- těhotenský plazmatický protein A MeSH
- troponin chemie MeSH
- Check Tag
- lidé MeSH
- MeSH
- dietní proteiny MeSH
- dietní sacharidy diagnostické užití MeSH
- dietní tuky analýza MeSH
- ketony chemie MeSH
- kyseliny mandlové chemie MeSH
- kyseliny mastné neesterifikované chemie MeSH
- lidé anatomie a histologie psychologie růst a vývoj MeSH
- mastné kyseliny chemie MeSH
- obezita diagnóza farmakoterapie klasifikace metabolismus prevence a kontrola psychologie rehabilitace terapie MeSH
- tělesná hmotnost fyziologie MeSH
- Check Tag
- lidé anatomie a histologie psychologie růst a vývoj MeSH
- ženské pohlaví MeSH
