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Évora AS, Zhang Z, Johnson SA, Adams MJ. The effects of hydration on the topographical and mechanical properties of corneocytes. J Mech Behav Biomed Mater 2024; 150:106296. [PMID: 38141363 DOI: 10.1016/j.jmbbm.2023.106296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/04/2023] [Accepted: 12/02/2023] [Indexed: 12/25/2023]
Abstract
It is well established that the biomechanical properties of the Stratum Corneum (SC) are influenced by both moisture-induced plasticization and the lipid content. This study employs Atomic Force Microscopy to investigate how hydration affects the surface topographical and elasto-viscoplastic characteristics of corneocytes from two anatomical sites. Volar forearm cells underwent swelling when immersed in water with a 50% increase in thickness and volume. Similarly, medial heel cells demonstrated significant swelling in volume, accompanied by increased cell area and reduced cell roughness. Furthermore, as the water activity was increased, they exhibited enhanced compliance, leading to a decreased Young's modulus, hardness, and relaxation times. Moreover, the swollen cells also displayed a greater tolerance to strain before experiencing permanent deformation. Despite the greater predominance of immature cornified envelopes in plantar skin, the comparable Young's modulus of medial heel and forearm corneocytes suggests that cell stiffness primarily relies on the keratin matrix rather than on the cornified envelope. The Young's moduli of the cells in distilled water are similar to those reported for the SC, which suggests that the corneodesmosomes and intercellular lamellae lipids junctions that connect the corneocytes are able to accommodate the mechanical deformations of the SC.
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Affiliation(s)
- Ana S Évora
- School of Chemical Engineering, University of Birmingham, Birmingham, UK.
| | - Zhibing Zhang
- School of Chemical Engineering, University of Birmingham, Birmingham, UK.
| | - Simon A Johnson
- School of Chemical Engineering, University of Birmingham, Birmingham, UK.
| | - Michael J Adams
- School of Chemical Engineering, University of Birmingham, Birmingham, UK.
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Évora AS, Zhang Z, Johnson SA, Adams MJ. Characterisation of topographical, biomechanical and maturation properties of corneocytes with respect to anatomical location. Skin Res Technol 2023; 29:e13507. [PMID: 38009042 PMCID: PMC10591027 DOI: 10.1111/srt.13507] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/12/2023] [Indexed: 11/28/2023]
Abstract
BACKGROUND The Stratum Corneum (SC) is the first barrier of the skin. The properties of individual cells are crucial in understanding how the SC at different anatomical regions maintains a healthy mechanical barrier. The aim of the current study is to present a comprehensive description of the maturation and mechanical properties of superficial corneocytes at different anatomical sites in the nominal dry state. MATERIALS AND METHODS Corneocytes were collected from five anatomical sites: forearm, cheek, neck, sacrum and medial heel of 10 healthy young participants. The surface topography was analysed using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). The level of positive-involucrin cornified envelopes (CEs) and desmoglein-1 (Dsg1) were used as indirect measures of immature CEs and corneodesmosomes, respectively. In addition, AFM nanoindentation and stress-relaxation experiments were performed to characterise the mechanical properties. RESULTS Volar forearm, neck and sacrum corneocytes presented similar topographies (ridges and valleys) and levels of Dsg1 (13-37%). In contrast, cheek cells exhibited circular nano-objects, while medial heel cells were characterized by villi-like structures. Additionally, medial heel samples also showed the greatest level of immature CEs (32-56%, p < 0.001) and Dsg1 (59-78%, p < 0.001). A large degree of inter-subject variability was found for the Young's moduli of the cells (0.19-2.03 GPa), which was correlated with the level of immature CEs at the cheek, neck and sacrum (p < 0.05). CONCLUSION It is concluded that a comprehensive study of the mechanical and maturation properties of corneocytes may be used to understand the barrier functions of the SC at different anatomical sites.
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Affiliation(s)
- Ana S. Évora
- School of Chemical EngineeringUniversity of BirminghamBirminghamUK
| | - Zhibing Zhang
- School of Chemical EngineeringUniversity of BirminghamBirminghamUK
| | - Simon A. Johnson
- School of Chemical EngineeringUniversity of BirminghamBirminghamUK
| | - Michael J. Adams
- School of Chemical EngineeringUniversity of BirminghamBirminghamUK
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Évora AS, Abiakam N, Zhang Z, Johnson SA, Adams MJ, Bader DL, Worsley PR. Characterisation of superficial corneocyte properties over category I pressure ulcers: Insights into topographical and maturation changes. J Dermatol Sci 2023; 112:63-70. [PMID: 37953180 DOI: 10.1016/j.jdermsci.2023.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/19/2023] [Accepted: 08/31/2023] [Indexed: 11/14/2023]
Abstract
BACKGROUND Pressure ulcers (PUs) are chronic wounds that are detrimental to the quality of life of patients. Despite advances in monitoring skin changes, the structure and function of skin cells over the site of pressure ulcers are not fully understood. OBJECTIVE The present study aims to evaluate local changes in the properties of superficial corneocytes in category 1 PU sites sampled from a cohort of hospitalised patients. METHODS Cells were collected from a PU-compromised site and an adjacent control area and their topographical, maturation and mechanical properties were analysed. RESULTS Corneocytes at the PU-compromised site were characterised by higher levels of immature cornified envelopes (p < 0.001) and greater amounts of desmoglein-1 (corneodesmosomal protein) (p < 0.001) compared to the adjacent control area. The cells at the control site presented the typical ridges-and-valleys topographical features of sacrum corneocytes. By contrast, the PU cells presented circular nano-objects at the cell surface, and, for some patients, the cell topography was deformed. CEs at the PU site were also smaller than at the control site. Although differences were not observed in the mechanical properties of the cells, those of the elderly patients were much softer compared with young subjects. CONCLUSION This is the first study investigating the changes in corneocyte properties in category I pressure ulcers. Superficial cells at the PU sites showed altered topographical and maturation characteristics. Further studies are required to elucidate if these changes are a consequence of early loss of skin integrity or a result of mechanical and microclimate insults to the skin surface.
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Affiliation(s)
- Ana S Évora
- School of Chemical Engineering, University of Birmingham, Birmingham, UK.
| | - Nkemjika Abiakam
- School of Health Sciences, University of Southampton, Southampton, UK
| | - Zhibing Zhang
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Simon A Johnson
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Michael J Adams
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Dan L Bader
- School of Health Sciences, University of Southampton, Southampton, UK
| | - Peter R Worsley
- School of Health Sciences, University of Southampton, Southampton, UK
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S Évora A, Abiakam N, Jayabal H, Worsley PR, Zhang Z, A Johnson S, J Adams M, Bader DL. Characterisation of superficial corneocytes in skin areas of the face exposed to prolonged usage of respirators by healthcare professionals during COVID-19 pandemic. J Tissue Viability 2023; 32:305-313. [PMID: 36813598 PMCID: PMC9918437 DOI: 10.1016/j.jtv.2023.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/27/2023] [Accepted: 02/10/2023] [Indexed: 02/13/2023]
Abstract
INTRODUCTION During the COVID-19 pandemic healthcare workers (HCWs) have used respiratory protective equipment for prolonged periods, which has been associated with detrimental effects on the underlying skin. The present study aims to evaluate changes in the main cells (corneocytes) of the stratum corneum (SC) following prolonged and consecutive use of respirators. METHODS 17 HCWs who wore respirators daily during routine hospital practice were recruited to a longitudinal cohort study. Corneocytes were collected via tape stripping from a negative control site (area outside the respirator) and from the cheek which was in contact with the device. Corneocytes were sampled on three occasions and analysed for the level of positive-involucrin cornified envelopes (CEs) and the amount of desmoglein-1 (Dsg1), as indirect measurements of immature CEs and corneodesmosomes (CDs), respectively. These were compared to biophysical measurements (Transepidermal water loss, TEWL, and SC hydration) at the same investigation sites. RESULTS A large degree of inter-subject variability was observed, with maximum coefficients of variation of 43% and 30% for the level of immature CEs and Dsg1, respectively. Although it was observed that there was not an effect of prolonged respirator usage on the properties of corneocytes, the level of CDs was greater at the cheek than the negative control site (p < 0.05). Furthermore, low levels of immature CEs correlated with greater TEWL values after prolonged respirator application (p < 0.01). It was also noted that a smaller proportion of immature CEs and CDs was associated with a reduced incidence of self-reported skin adverse reactions (p < 0.001). CONCLUSIONS This is the first study that investigated changes in corneocyte properties in the context of prolonged mechanical loading following respirator application. Although differences were not recorded over time, the levels of CDs and immature CEs were consistently higher in the loaded cheek compared to the negative control site and were positively correlated with a greater number of self-reported skin adverse reactions. Further studies are required to evaluate the role of corneocyte characteristics in the evaluation of both healthy and damaged skin sites.
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Affiliation(s)
- Ana S Évora
- School of Chemical Engineering, University of Birmingham, Birmingham, UK.
| | - Nkemjika Abiakam
- School of Health Sciences, University of Southampton, Southampton, UK
| | - Hemalatha Jayabal
- School of Health Sciences, University of Southampton, Southampton, UK
| | - Peter R Worsley
- School of Health Sciences, University of Southampton, Southampton, UK
| | - Zhibing Zhang
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Simon A Johnson
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Michael J Adams
- School of Chemical Engineering, University of Birmingham, Birmingham, UK
| | - Dan L Bader
- School of Health Sciences, University of Southampton, Southampton, UK
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Voegeli R, Cherel M, Schoop R, Rawlings AV. A comprehensive comparison of facial skin hydration based on capacitance and conductance measurements in Chinese women. Int J Cosmet Sci 2022; 44:703-718. [PMID: 35980652 PMCID: PMC9826081 DOI: 10.1111/ics.12814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/17/2022] [Accepted: 08/17/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVES The aim of this study was to compare the data of conductance and capacitance measurements of facial skin hydration and to evaluate and discuss the advantages and disadvantages of the different approaches. METHODS We measured skin capacitance (Corneometer® CM 825) and skin conductance (Skicon-200EX®) on 30 pre-defined facial sites of 125 Chinese women, resulting in 3750 readings per device. The data were analysed and compared, and continuous colour maps were generated on a 3D avatar for capacitance, conductance, relative difference (Δ%) and correlation (R-value) by interpolating between the individual readings and converting the values to colours. This visualization allows a better interpretation of the results. RESULTS The complexity of facial skin hydration is revealed by this approach. The similarities and discrepancies in the facial hydration maps are clearly apparent. Due to the superiority of the Skicon in measuring high hydration levels, differences in skin hydration were evident on the forehead compared with the Corneometer maps, which may be related to the more superficial measurement of the Skicon within the stratum corneum. Conversely, a greater understanding of the complexity of facial skin hydration in the nasolabial fold was obvious when using the Corneometer. The best congruence between the instruments was found at two specific but separated facial areas, one around the inner eye region and the other one on a line between the nasolabial sulcus and the oblique, lateral jaw. Interestingly, the data were not normally distributed for both instruments and they had opposite skews. All facial clusters were statistically different from each other (p < 0.001), except the cheek and jaw for the Skicon. Larger than expected percentage coefficients of variance were found for the Corneometer on some facial sites that might be explainable by differences in stratum corneum physiology and biochemistry. Corneometer values of 48 AU and Skicon values of 132 μS were taken as the cutoff for normally hydrated facial skin. CONCLUSIONS Both devices have their advantages and disadvantages suggesting that bio-instrumental measurement of skin hydration is actually more complicated than commonly thought and that the different facial zones and the use of multiple instrumentation have not been adequately considered.
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Gorcea M, Lane ME, Moore DJ. Exploratory In Vivo Biophysical Studies of Stratum Corneum Lipid Organization in Human Face and Arm Skin. Int J Pharm 2022; 622:121887. [DOI: 10.1016/j.ijpharm.2022.121887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 10/18/2022]
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Rawlings AV, Schoop R, Klose C, Monneuse J, Summers B, Voegeli R. Changes in levels of omega-O-acylceramides and related processing enzymes of sun-exposed and sun-protected facial stratum corneum in differently pigmented ethnic groups. Int J Cosmet Sci 2022; 44:166-176. [PMID: 35141910 PMCID: PMC9313807 DOI: 10.1111/ics.12765] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/07/2022] [Indexed: 12/04/2022]
Abstract
INTRODUCTION We report on the differences in ceramide composition and levels of omega-O-acylceramide processing enzymes of sun-exposed and sun-protected facialstratum corneum (SC) among Albino African, Black African and Caucasian women living in South Africa. METHODS Tape strippings were taken from the sun-exposed cheek and the sunprotected postauricular site (PA). In two subsets proteomic (n = 18) and lipidomic (n = 24) analysis were performed using mass-spectrometry-based shotgun platforms. RESULTS No significant differences in total ceramide levels or ceramide subtypes were found between the Black African and Caucasian women in either the cheek or PA samples. Compared to the other two groups the levels of total ceramide as well as selected omega-O-acylceramide species were increased in Albino Africans. On the cheek, ceramide (CER) EOS, EOH along with CER AS were increased relative to the Caucasian women, while CER EOP and EOdS were elevated relative to the Black African women. Moreover, on the PA site CER EOP and EOdS were elevated compared with the Black African women and CER EOdS in Caucasians. Decreasesin masslevels of 12R-LOX and eLOX3 were observed on cheeks compared with the PA sites in all ethnic groups. On the PA sites 12R-LOX was particularly lower in the Albino Africans compared with the Black African and Caucasian women. On the cheeks mass levels of SDR9C7 was also lower in the Albino Africans. CONCLUSION The mass levels of the ceramides were similar between Black African and Caucasian women. However, elevated total ceramides and excessively elevated selected omega-O-acylceramides were apparent in the Albino African women. The findings in the Albino African women were unexpected as these participants suffer from impaired skin barrier function. However, the elevated levels omega-O-acylceramides can contribute to barrier insufficiency by directly impacting SC lipid phase behaviour and/or secondly elevated omegaO-acylceramide levels may indicate a reduced attachment of ceramides to the corneocyte lipid envelope and reduced corneocyte maturation that can also impair the barrier. Indeed, differences in the mass levels of omega-O-acylceramide processing enzymes were observed for 12R-LOX and SDR9C7 for the Albino Africans. This indicates a corneocyte lipid scaffold disorder in this population.
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Évora AS, Adams MJ, Johnson SA, Zhang Z. Corneocytes: Relationship between Structural and Biomechanical Properties. Skin Pharmacol Physiol 2021; 34:146-161. [PMID: 33780956 DOI: 10.1159/000513054] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/13/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Skin is the interface between an organism and the external environment, and hence the stratum corneum (SC) is the first to withstand mechanical insults that, in certain conditions, may lead to integrity loss and the development of pressure ulcers. The SC comprises corneocytes, which are vital elements to its barrier function. These cells are differentiated dead keratinocytes, without organelles, composed of a cornified envelope and a keratin-filled interior, and connected by corneodesmosomes (CDs). SUMMARY The current review focusses on the relationship between the morphological, structural, and topographical features of corneocytes and their mechanical properties, to understand how they assist the SC in maintaining skin integrity and in responding to mechanical insults. Key Messages: Corneocytes create distinct regions in the SC: the inner SC is characterized by immature cells with a fragile cornified envelope and a uniform distribution of CDs; the upper SC has resilient cornified envelopes and a honeycomb distribution of CDs, with a greater surface area and a smaller thickness than cells from the inner layer. The literature indicates that this upward maturation process is one of the most important steps in the mechanical resistance and barrier function of the SC. The morphology of these cells is dependent on the body site: the surface area in non-exposed skin is about 1,000-1,200 μm2, while for exposed skin, for example, the cheek and forehead, is about 700-800 μm2. Corneocytes are stiff cells compared to other cellular types, for example, the Young's modulus of muscle and fibroblast cells is typically a few kPa, while that of corneocytes is reported to be about hundreds of MPa. Moreover, these skin cells have 2 distinct mechanical regions: the cornified envelope (100-250 MPa) and the keratin matrix (250-500 MPa).
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Affiliation(s)
- Ana S Évora
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Michael J Adams
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Simon A Johnson
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Zhibing Zhang
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
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Voegeli R, Guneri D, Cherel M, Summers B, Lane ME, Rawlings AV. Topical niacinamide enhances hydrophobicity and resilience of corneocyte envelopes on different facial locations. Int J Cosmet Sci 2020; 42:632-636. [PMID: 33038007 PMCID: PMC8365309 DOI: 10.1111/ics.12666] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 09/24/2020] [Indexed: 12/27/2022]
Abstract
Age-related differences in maturation parameters of corneocyte envelopes (size, hydrophobicity and rigidity) were examined at several facial test sites in young and old female Caucasians. In addition, the effect of topically applied niacinamide on these parameters was evaluated in a 4-week placebo-controlled study.
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Affiliation(s)
- R Voegeli
- DSM Nutritional Products Ltd, Wurmisweg 576, 4303 Kaiseraugst, Switzerland
| | - D Guneri
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK
| | - M Cherel
- Newtone Technologies, 13bis, place Jule Ferry, 69006, Lyon, France
| | - B Summers
- Sefako Makgatho Health Sciences University, Basic Medical Sciences Building, Room N311, 3rd Floor, Molotlegi St., Medunsa 0204, Pretoria, Gauteng, South Africa
| | - M E Lane
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK
| | - A V Rawlings
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK.,AVR Consulting Ltd, 26 Shavington Way, Kingsmead, CW9 8FH, Northwich, Cheshire, UK
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Rawlings A. Microbes: Fighting for space on a fragile interface. Int J Cosmet Sci 2020; 42:310-312. [DOI: 10.1111/ics.12616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 03/17/2020] [Indexed: 11/27/2022]
Affiliation(s)
- A.V. Rawlings
- Director AVR Consulting Limited 26 Shavington Way Northwich Cheshire CW98FHUnited Kingdom
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Guneri D, Voegeli R, Doppler S, Zhang C, Bankousli AL, Munday MR, Lane ME, Rawlings AV. The importance of 12R-lipoxygenase and transglutaminase activities in the hydration-dependent ex vivo maturation of corneocyte envelopes. Int J Cosmet Sci 2020; 41:563-578. [PMID: 31429091 PMCID: PMC6899781 DOI: 10.1111/ics.12574] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/18/2019] [Indexed: 12/26/2022]
Abstract
Background Terminally differentiated keratinocytes acquire corneocyte protein envelopes (CPE) complexed with corneocyte lipid envelopes (CLE). These two structural components of the corneocyte envelopes (CEs) undergo maturation by gaining in hydrophobicity, rigidity and surface area. Linoleoyl acylceramides are processed by 12R‐lipoxygenase (12R‐LOX) and other enzymes before transglutaminase (TG) attaches ω‐hydroxyceramides to involucrin in the CPE. Concurrently, structural proteins are cross‐linked by TG that has been activated by cathepsin D (CathD). Objectives The primary aim of this work was to demonstrate the impact of relative humidity (RH) during ex vivo CE maturation. Low, optimal and high RH were selected to investigate the effect of protease inhibitors (PIs) on CE maturation and TG activity; in addition, 12R‐LOX and CathD activity were measured at optimal RH. Finally, the effect of glycerol on ex vivo CE maturation was tested at low, optimal and high RH. Methods The first and ninth tape strip of photo‐exposed (PE) cheek and photo‐protected (PP) post‐auricular sites of healthy volunteers were selected. Ex vivo CE maturation was assessed via the relative CE maturity (RCEM) approach based on CE rigidity and hydrophobicity. The second and eighth tapes were exposed to RH in the presence of inhibitors. Results Irrespective of tape stripping depth, CEs from PE samples attained CE rigidity to the same extent as mature CEs from the PP site, but such improvement was lacking for CE hydrophobicity. 70% RH was optimal for ex vivo CE maturation. The inhibition of 12R‐LOX activity resulted in enhanced CE rigidity which was reduced by the TG inhibitor. CE hydrophobicity remained unchanged during ex vivo maturation in the presence of TG or 12R‐LOX inhibition. CE hydrophobicity was enhanced in the presence of glycerol at 44% RH and 100% RH but not at 70% RH. Furthermore, TG activity was significantly diminished at 100% RH compared to the commercial inhibitor LDN‐27219. However, a protease inhibitor mix reversed the negative effect of overhydration. Conclusion The study adds to the understanding of the roles of 12R‐LOX and TG activity in CE maturation and gives further insight into the effect of glycerol on the SC.
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Affiliation(s)
- D Guneri
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK
| | - R Voegeli
- DSM Nutritional Products Ltd., Wurmisweg 576, 4303, Kaiseraugust, Switzerland
| | - S Doppler
- DSM Nutritional Products Ltd., Wurmisweg 576, 4303, Kaiseraugust, Switzerland
| | - C Zhang
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK
| | - A L Bankousli
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK
| | - M R Munday
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK
| | - M E Lane
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK
| | - A V Rawlings
- UCL School of Pharmacy, 29-39 Brunswick Square, WC1N 1AX, London, UK.,AVR Consulting Limited, 26 Shavington Way, CW98FH, Northwich, UK
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Guneri D, Voegeli R, Munday MR, Lane ME, Rawlings AV. 12R-lipoxygenase activity is reduced in photodamaged facial stratum corneum. A novel activity assay indicates a key function in corneocyte maturation. Int J Cosmet Sci 2019; 41:274-280. [PMID: 30993698 PMCID: PMC6852689 DOI: 10.1111/ics.12532] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 04/11/2019] [Indexed: 12/13/2022]
Abstract
Background During the late stage of keratinocyte differentiation, corneocytes gain a strong protein–lipid structure: the corneocyte envelopes (CE), composed of the inner corneocyte protein envelope (CPE) and the outer corneocyte lipid envelope (CLE). The hydrophobicity of CEs depends on the covalent attachment of linoleoyl‐acyl‐ceramides by transglutaminases (TG). These ceramides are processed by a range of other enzymes, including 12R‐lipoxygenase (12R‐LOX), before the covalent attachment of the free ω‐hydroxyceramides to the CPE surface to form the CLE. The mechanical strength of CE is obtained with the formation of isodipeptide bonds by TG. The increase in hydrophobicity and rigidity leads to CE maturation which supports the integrity and mechanical resistance of the stratum corneum (SC). Objectives The aim of this work was to develop and validate a novel enzyme activity assay for 12R‐LOX in tape strippings of photo‐exposed (PE) cheek and photo‐protected (PP) post‐auricular SC of healthy Chinese volunteers (n = 12; age 25 ± 3 years). Results A fluorescence‐based assay was developed with ethyl linoleic acid as the substrate and a polyclonal antibody against 12R‐LOX as an inhibitor. The specificity was shown by the lack of effect by a LOX inhibitor (ML351) and an epidermal‐type lipoxygenase 3 (eLOX3) antibody on the acquired 12R‐LOX activity. Reduced 12R‐LOX activity was observed in the outer compared to the inner SC layers. Moreover, dramatically lower activity was shown in the PE vs. PP samples. Furthermore, the enzyme activity has a positive correlation (r = 0.94 ± 0.03) with CE maturity, in particular hydrophobicity, and a negative correlation (r = −0.96 ± 0.01) with transepidermal water loss (TEWL). Conclusion This novel enzyme assay revealed a lower 12R‐LOX activity in tape strippings from PE cheek for the first time. This finding is in line with less mature CEs and higher TEWL compared to PP post‐auricular samples. This study indicates a strong link between 12R‐LOX activity and CE maturation and SC integrity.
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Affiliation(s)
- D Guneri
- UCL School of Pharmacy, London, UK
| | - R Voegeli
- DSM Nutritional Products Ltd, Kaiseraugust, Switzerland
| | | | - M E Lane
- UCL School of Pharmacy, London, UK
| | - A V Rawlings
- UCL School of Pharmacy, London, UK.,AVR Consulting Ltd, Northwich, UK
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