Cosmetic benefits of a novel biomimetic lamellar formulation containing niacinamide in healthy females with oily, blemish-prone skin in a randomized proof-of-concept study.

OBJECTIVE: A randomized study was designed to evaluate the potential cosmetic benefit of a biomimetic, niacinamide-containing moisturizing cream in oily, blemish-prone skin. METHODS: Healthy adult women with oily, blemish-prone skin were randomized to one of three treatment groups: test, control, or positive control. In the test group, subjects used the test product (containing 4% niacinamide), plus the standard cleanser (Simple® Kind to Skin Moisturizing Facial Wash). In the control group, subjects received no moisturizer but used the standard cleanser. In the positive control group, subjects used Vivatinell Acnecinamide® Gel Cream (containing 4% niacinamide) as a moisturizer and Neutrogena Visibly Clear® Spot Clearing Facial Wash (containing 2% salicylic acid) as a cleanser. The positive control regimen was included to provide a comparison for estimates of effect size. The primary objective was to evaluate skin moisturization as a change from baseline in corneometer values at 8 h for the test regimen vs. the control regimen. Analysis of covariance was applied for the primary efficacy analysis. RESULTS: A total of 132 subjects were randomized with 44 included in each treatment group. A significant difference was observed in the primary endpoint for the test regimen compared with the control regimen (least-squares mean difference [95% CI]: 3.12 [0.68, 5.56], P = 0.0128). A trend was observed in favour of the positive control regimen compared with the control regimen. Secondary measurements of moisturization supported the primary efficacy outcome. Assessment of blemishes showed a significant difference between the test regimen vs. the control regimen for change from baseline in mean total blemish count at Week 8 (least-squares mean difference [95% CI]: -1.80 [-3.41, -0.19], P = 0.0290). No statistical comparisons between the positive control group and the test group were performed. CONCLUSION: This study provides proof-of-concept evidence that a novel lamellar lipid moisturizer containing niacinamide, in combination with a standard cleanser, can help moisturize the skin and provide an overall improvement in the complexion appearance of people with blemish-prone skin. STUDY REGISTRATION: NCT03093181.

OBJECTIF: Une étude randomisée a été conçue pour évaluer le bénéfice cosmétique potentiel d'une crème hydratante biomimétique contenant du niacinamide sur une peau grasse sujette aux imperfections. MÉTHODES: Des femmes adultes en bonne santé, à peau grasse sujette aux imperfections, ont été randomisées dans l'un des trois groupes de traitement : test, témoin ou témoin positif. Dans le groupe test, les sujets ont utilisé le produit testé (contenant 4 % de niacinamide), plus le nettoyant standard (Nettoyant visage Simple® doux pour la peau). Dans le groupe témoin, les sujets n'ont reçu aucune crème hydratante mais ont utilisé le nettoyant standard. Dans le groupe témoin positif, les sujets ont utilisé le gel crème Vivatinell Acnecinamide® (contenant 4 % de niacinamide) comme crème hydratante et le nettoyant visage pour réduire les imperfections Neutrogena Visibly Clear® (contenant 2 % d'acide salicylique) comme nettoyant. Le schéma de traitement du groupe témoin positif était inclus pour fournir une comparaison des estimations de la taille de l'effet. L'objectif principal était d'évaluer l'hydratation de la peau par le changement par rapport à la référence des valeurs du cornéomètre à 8 h pour le schéma de traitement testé par rapport au schéma de traitement témoin. Une analyse de covariance a été appliquée pour l'analyse de l'efficacité primaire. RÉSULTATS: Un total de 132 sujets ont été randomisés, dont 44 inclus dans chaque groupe de traitement. Une différence significative a été observée dans le critère d'évaluation principal en faveur du schéma de traitement testé par rapport au schéma de traitement témoin (différence moyenne des moindres carrés [IC à 95 %] : 3,12 [0,68, 5,56], P = 0,0128). Une tendance a été observée en faveur du schéma de traitement témoin positif par rapport au schéma de traitement témoin. Les mesures secondaires de l'hydratation ont appuyé le résultat principal d'efficacité. L'évaluation des imperfections a montré une différence significative entre le schéma de traitement testé par rapport au schéma de traitement témoin en ce qui concerne le changement par rapport à la référence dans le nombre moyen total d'imperfections à la semaine 8 (différence moyenne des moindres carrés [IC à 95 %] : _1,80 [_3,41, _0,19], P = 0,0290). Aucune comparaison statistique entre le groupe témoin positif et le groupe test n'a été réalisée. CONCLUSION: Cette étude fournit des éléments de preuve de concept qu'une nouvelle crème hydratante lipidique lamellaire à base de niacinamide, en association avec un nettoyant standard, peut permettre d'hydrater la peau et fournir une amélioration globale de l'aspect du teint chez des personnes dont la peau est sujette aux imperfections. Numéro d'enregistrement de l'étude : NCT03093181.

3D-Printed Franz cells - update on optimization of manufacture and evaluation.

OBJECTIVES: Laboratory in vitro permeation processes require the use of modified Franz type diffusion cells which are conventionally fabricated from glass. Fragility and high cost are frequently associated with this type of laboratory apparatus. The purpose of our present research was to develop a simple, economical and versatile approach to manufacture Franz type cells using additive manufacturing (AM). METHODS: Graphical Franz diffusion cell designs were reproduced with a stereolithography (SLA) 3D printer and assessed over a minimum period of 24 h. The surface morphology of AM printouts was analysed before and after compatibility studies using scanning electron microscopy (SEM). Comparative permeation studies in both glass and AM Franz type diffusion cells were conducted using a caffeine solution (1.5 mg mL-1 ), applied to a model silicone membrane. RESULTS: Testing of the 3D printed scaffolds confirmed similar recovery of the permeant when compared to glass cells: 1.49 ± 0.01 and 1.50 ± 0.01 mg mL-1 , respectively, after 72 h. No significant differences were visible from the SEM micrographs demonstrating consistent, smooth and non-porous surfaces of the AM Franz cells' core structure. Permeation studies using transparent 3D printed constructs resulted in 12.85 ± 0.53 µg cm-2 caffeine recovery in the receptor solution after 180 min with comparable permeant recovery, 11.49 ± 1.04 µg cm-2 , for the glass homologues. CONCLUSION: AM constructs can be considered as viable alternatives to the use of conventional glass apparatus offering a simple, reproducible and cost-effective method of replicating specialised laboratory glassware. A wider range of permeants will be investigated in future studies with these novel 3D printed Franz diffusion cells.

OBJECTIF: les processus de perméation in vitro en laboratoire nécessitent l'utilisation de cellules de diffusion de type Franz modifiées, fabriquées traditionnellement en verre. La fragilité et un coût élevé sont fréquemment associés à ce type d'appareil de laboratoire. L'objectif de nos travaux de recherche actuels était de développer une approche simple, économique et polyvalente pour fabriquer des cellules de type Franz à l'aide de la fabrication additive (FA). MÉTHODES: les conceptions des cellules de diffusion Franz graphiques ont été reproduites avec une imprimante 3D stéréolithographie (SLA) et évaluées sur une période minimum de 24 h. La morphologie de surface des impressions FA a été analysée avant et après des études de compatibilité à l'aide de la microscopie électronique à balayage (MEB). Des études comparatives de perméation des cellules de diffusion de type Franz en verre et FA ont été réalisées à l'aide d'une solution de caféine (1,5 mg ml-1 ) appliquée à un modèle de membrane en silicone. RÉSULTATS: les tests des supports imprimés 3D ont confirmé une récupération similaire du perméant par rapport aux cellules de verre : 1,49 ± 0,01 et 1,50 ± 0,01 mg ml-1 , respectivement, après 72 h. Aucune différence significative n'a été observée sur les micrographiques MEB, montrant des surfaces cohérentes, lisses et non poreuses de la structure centrale des cellules Franz FA. Les études de perméation utilisant des constructions transparentes imprimées en 3D ont conduit à une récupération de la caféine de 12,85 ± 0,53 µg cm-2 dans la solution de récepteur après 180 min avec une récupération de perméant comparable, 11,49 ± 1,04 µg cm-2 , pour les homologues de verre. CONCLUSION: les constructions FA peuvent être considérées comme des alternatives viables à l'utilisation d'appareils de verre conventionnels offrant une méthode simple, reproductible et rentable de réplication de la verrerie de laboratoire spécialisée. Une gamme plus large de perméants sera étudiée dans de futures études avec ces nouvelles cellules de diffusion Franz imprimées en 3D.

A proof-of-principle study comparing barrier function and cell morphology in face and body skin.

OBJECTIVE: The purpose of this pilot in vivo study was to investigate corneocyte size and transepidermal water loss (TEWL) in facial cheek and volar forearm skin as a function of consecutive tape stripping. Changes in corneocyte size and transepidermal water loss (TEWL) were measured as a function of stratum corneum (SC) depth at both anatomical sites. To our knowledge, this is the first published quantitative comparison based on these parameters. This work complements our previously published studies on face skin barrier recovery at 24 h and 4 weeks post-tape stripping [Gorcea et al., Skin Res. Technol., 19, 2013, e375-e382; Gorcea et al., Int. J. Cosmet. Sci. 35, 2013, 250]. METHODS: Transepidermal water loss in vivo measurements of forearm and facial skin sites were taken before tape stripping commenced (baseline) and after each tape was collected. Optical microscopy and image analysis techniques were employed to characterize corneocyte size as a function of skin depth (tape strip number) for both anatomical sites. RESULTS: Transepidermal water loss increased significantly from baseline with sequential tape stripping at both anatomical skin sites. Volar forearm skin required approximately three times as many tapes to 'damage' the SC barrier (arbitrarily defined as twice baseline TEWL) compared to facial cheek skin demonstrating significant differences in barrier properties between cheeks and forearms (P < 0.05). Corneocyte size decreased significantly with depth for both sites (P < 0.001). Corneocytes from face skin were significantly smaller than corneocytes from volar forearm skin. CONCLUSION: Statistically significant differences between facial and body skin stratum corneum cell morphology and transepidermal water loss were demonstrated and quantitatively measured as a function of tape stripping.

OBJECTIF: L'objectif de cette étude pilote in vivo était d'étudier la taille des cornéocytes et la perte d'eau transépidermique (TEWL) dans la peau des joues et des avant-bras comme en fonction de l'épilation par bandelettes. Les modifications de la taille des cornéocytes et de la perte d'eau transépidermique (TEWL) ont été mesurées en fonction de la profondeur du stratum corneum (SC) au niveau des deux sites anatomiques. À notre connaissance, il s'agit de la première comparaison quantitative publiée sur la base de ces paramètres. Ce travail complète nos études publiées antérieurement sur la récupération de la barrière cutanée du visage 24 h et 4 semaines après l'application des bandelettes. [Gorcea et al., Skin Res. Technol., 19, 2013, e375-e382; Gorcea et al., Int. J. Cosmet. Sci. 35, 2013, 250]. MÉTHODES: Les mesures de la perte d'eau transépidermique in vivo au niveau des sites cutanés des avant-bras et du visage ont été effectuées avant le début du retrait des bandelettes (référence) et après le prélèvement de chaque bandelette. Des techniques de microscopie optique et d'analyse d'images ont été utilisées pour caractériser la taille des cornéocytes en fonction de la profondeur de la peau (numéro de bandelette) pour les deux sites anatomiques. RÉSULTATS: La perte d'eau transépidermique a augmenté de façon significative par rapport à la référence lors du retrait séquentiel des bandelettes au niveau des deux sites anatomiques de la peau. La peau de l'avant-bras a nécessité environ trois fois plus de bandelettes pour « endommager ¼ la barrière du SC (définie arbitrairement comme deux fois la TEWL de base) que la peau des joues du visage, ce qui démontre des différences significatives dans les propriétés barrières entre les joues et les avant-bras (P < 0,05). La taille des cornéocytes a diminué de façon significative avec la profondeur pour les deux sites (P < 0,001). Les cornéocytes de la peau du visage étaient significativement plus petits que les cornéocytes de la peau de l'avant-bras. CONCLUSION: Des différences statistiquement significatives de morphologie et de perte d'eau transépidermique entre les cellules du stratum corneum de la peau du visage et celles du corps ont été démontrées et mesurées quantitativement en fonction du retrait des bandelettes.

Clinical and in vitro evaluation of new anti-redness cosmetic products in subjects with winter xerosis and sensitive skin.

OBJECTIVE: To demonstrate the in vitro activities of panthenol, palmitoylethanolamide (PEA), and niacinamide (NAM) and determine the biophysical properties, clinical safety, tolerability together with efficacy of two developmental anti-redness (AR) formulations containing these ingredients, in alleviating facial redness associated with winter xerosis in healthy volunteers with sensitive skin. METHODS: The anti-inflammatory and skin protective properties of panthenol, PEA and NAM were evaluated in vitro. The physical properties of the AR formulations were analysed using measurement of water vapour transport rate (WVTR) and infrared spectroscopy. Clinical studies were performed between the months of December and April (2014-2015) with efficacy assessed during the winter. Facial redness, irritation, sensitization potential, photo-irritation, and photo-sensitization were evaluated. Self-assessed adverse reactions were reported in diaries of use. RESULTS: Panthenol and PEA reduced prostaglandin E2 , interleukin-6, and thymic stromal lymphopoietin levels in vitro, while NAM induced nicotinamide adenine dinucleotide (NAD) levels and the keratinocyte differentiation markers: filaggrin (2-fold increase, P < 0.001), loricrin (2-fold increase, P < 0.05), involucrin (2 fold increase, P < 0.001) & peroxisomal proliferator activated receptor-alpha (1.5 fold increase, P < 0.05). The two AR products exhibited low WVTR vs. no treatment (P < 0.001) and displayed an ordered lipid structure. The day cream formulation protected against ultraviolet B radiation in vitro. A total of 382 participants were included in clinical studies which showed the AR formulations significantly improved facial redness associated with winter xerosis (Day 29 mean change from baseline: AR day cream 0.77 (P < 0.001); AR serum 0.67 (P < 0.001)). No irritation, sensitization, photo-irritation, photo-sensitization or product-related adverse reactions were observed or reported in the clinical studies. CONCLUSION: The new products significantly improved skin redness associated with winter xerosis in participants with self-perceived sensitive skin. Both products were well tolerated with a suitable safety profile for topical use in subjects with sensitive skin.

OBJECTIF: Démontrer l'activité in vitro du panthénol, du palmitoyléthanolamide (PEA), et du nicotinamide (NAM) et déterminer les propriétés biophysiques, la sécurité clinique, la tolérance ainsi que l'efficacité de deux formulations anti-rougeurs (AR) en développement contenant ces ingrédients pour atténuer les rougeurs faciales associées à la xérose hivernale chez des volontaires sains présentant une peau sensible. MÉTHODES: Les propriétés anti-inflammatoires et protectrices du panthénol, du PEA et du NAM ont été évaluées in vitro. Les propriétés physiques des formulations AR ont été analysées en mesurant le taux de transport de vapeur d'eau (WVTR) et par spectroscopie infrarouge. Des études cliniques ont été réalisées entre décembre et avril (2014-2015) et l'efficacité a été évaluée pendant l'hiver. Les rougeurs, l'irritation, le potentiel de sensibilisation, la photo-irritation et la photosensibilisation au niveau du visage ont été évalués. Des effets indésirables auto-évalués ont été signalés dans des journaux d'utilisation. RÉSULTATS: Le panthénol et le PEA ont réduit les niveaux de prostaglandine E2 , d'interleukine-6 et de lymphopoiétine stromale thymique in vitro, tandis que le NAM a généré une augmentation des taux de nicotinamide adénine dinucléotide (NAD) et des marqueurs de différenciation kératinocytaire : filaggrine (multiplication des taux par 2, P < 0,001), loricrine (multiplication des taux par 2, P < 0,05), involucrine (multiplication des taux par 2, P < 0,001) et du récepteur alpha activé de la prolifération peroxysomale (multiplication des taux par 1,5, P < 0,05). Les deux produits antirétroviraux présentaient un faible taux de WVTR par rapport à l'absence de traitement (P < 0,001) et présentaient une structure lipidique ordonnée. La formulation de la crème de jour protège contre le rayonnement ultraviolet B in vitro. Un total de 382 participants ont été inclus dans les études cliniques qui ont montré que les formulations AR amélioraient significativement les rougeurs faciales associées à la xérose hivernale (changement moyen du jour 29 par rapport à la référence : crème de jour AR 0,77 (P < 0,001) ; sérum AR 0,67 (P < 0,001)). Aucune irritation, sensibilisation, photo-irritation, photosensibilisation ni effet indésirable lié au produit n'a été observé ou signalé dans les études cliniques. CONCLUSION: Les nouveaux produits ont considérablement amélioré la rougeur de la peau associée à la xérose hivernale chez les participants présentant une peau sensible auto-perçue. Les deux produits ont été bien tolérés avec un profil de sécurité approprié pour un usage topique chez les sujets présentant une peau sensible.

Interactions of dipalmitoylphosphatidylcholine with ceramide-based mixtures.

The outermost layer of the skin, the stratum corneum (SC), acts as the natural physical barrier. The SC consists of corneocytes embedded in a crystalline lipid matrix consisting of ceramides, free fatty acids and cholesterol. Although phospholipids are frequently present in topical formulations, no detailed information is reported on the interactions between phospholipids and SC lipids. The aim of this study was to examine the interactions between a model phospholipid, dipalmitoylphosphatidylcholine (DPPC) and synthetic ceramide-based mixtures (referred to as SC lipids). (Perdeuterated) DPPC was mixed with SC lipids and the lipid organization and mixing properties were examined. The studies revealed that DPPC participates in the same lattice as SC lipids thereby enhancing a hexagonal packing. Even at a high DPPC level, no phase separated pure DPPC was observed. When a DPPC containing formulation is applied to the skin surface it must partition into the SC lipid matrix prior to any mixing with the SC lipids. To mimic this, DPPC was applied on top of a SC lipid membrane. DPPC applied in a liquid crystalline state was able to mix with the SC lipids and participated in the same lattice as the SC lipids. However, when DPPC was applied in a rippled gel-state very limited partitioning of DPPC into the SC lipid matrix occurred. Thus, when applied to the skin, liquid crystalline DPPC will have very different interactions with SC lipids than DPPC in a (rippled-)gel phase.

Use of LC-MS analysis to elucidate by-products of niacinamide transformation following in vitro skin permeation studies.

OBJECTIVE: To explore and elucidate the formation of niacinamide (NIA) by-products during in vitro skin permeation studies using liquid chromatography coupled to mass spectrometry (LC-MS) analysis. METHODS: Porcine skin permeation studies of various NIA formulations were conducted using Franz diffusion cells for a period of 24 hours. NIA by-products were identified by LC, extracted and further qualitatively analysed by LC-MS. RESULTS: Analysis and characterisation of NIA by-products using LC-MS resulted in the identification of different molecular entities with similar structures to NIA. The most prevalent molecular specie in this study was 1,4,5,6-tetrahydropyridine-3-carboxamide with the highest ion abundance. Other structural NIA analogues were also identified and reported, namely piperidine-3-carboxamide and 1,4-dihydropyridine-3-carboxamide. None of these NIA derivatives were detected in stability studies of NIA in the medium used as the receptor phase, phosphate buffered saline (PBS), that had not been in contact with skin. CONCLUSION: The comparatively low recovery of NIA following in vitro mass-balance and permeation studies for pseudo-finite and finite dosing of the active compared with infinite dosing is attributed to chemical derivatisation of the molecule during skin penetration. These findings reported here will allow the development of more sensitive methods to ensure full mass balance recovery of NIA following topical application of NIA preparations.

3D-printed Franz type diffusion cells.

OBJECTIVE: Franz cells are routinely used to measure in vitro skin permeation of actives and must be inert to the permeant under study. The aim of the present work was to develop and manufacture transparent Franz-type diffusion cells using 3D printing. Printouts were then tested using a range of model active compounds. The study also aims to identify the critical 3D-printing parameters necessary for the process, including object design, choice of printing resin, printout curing and post-curing settings and introduction of model coatings. METHODS: Transparent Franz cells were constructed using an online computer aided design program and reproduced with different stereolithography 3D printers. The two acrylate-based resins used for the fabrication process were a commercially available product and a polymer synthesised in-house. Comparative studies between glass and 3D-printed Franz cells were conducted with selected model actives: terbinafine hydrochloride (TBF), niacinamide (NIA), diclofenac free acid (DFA) and n-methyl paraben (MPB). In preliminary studies, MPB showed the lowest recovery when exposed to the receptor compartment of 3D printed cells. Consequently, in vitro permeation studies were carried out using only MPB with polydimethylsiloxane (PDMS) membrane. RESULTS: A decrease in the amounts of selected compounds was observed for transparent 3D-printed Franz cells compared to glass cells. MPB showed the lowest recovery (53.8 ± 13.1%) when compared with NIA (74.9 ± 4.0%), TBF (81.5 ± 12.0%) and DFA (90.2 ± 12.9%) after 72 h. Permeation studies conducted using 3D-printed transparent cells with PDMS membrane also showed a decrease in MPB recovery of 51.4 ± 3.7% for the commercial resin and 94.4 ± 3.5% for the polymer synthesised in-house, when compared to glass cells. Although hydrophobic coatings were subsequently applied to the 3D-printed cells, the same reduction in MPB concentration was observed in the receptor solution. CONCLUSION: Transparent Franz cells were successfully prepared using 3D printing and were observed to be robust and leak-proof. There are few resins currently available for preparation of transparent materials and incompatibilities between the actives investigated and the 3D-printed cells were evident. Hydrophobic coatings applied as barriers to the printed materials did not prevent these interactions.

The chemistry, function and (patho)physiology of stratum corneum barrier ceramides.

Research on understanding of the chemistry, function and (patho)physiology of stratum corneum (SC) lipids and especially ceramides has evolved over the last two decades. This has been made successful through the application of separation techniques that have become increasingly more sophisticated, and it has become increasingly evident that our understanding of these molecules remains in its infancy. Thirteen classes of ceramides with over 300 and possibly up to 1000 distinct ceramide species have been identified suggesting an exquisitely subtle relationship between the types of ceramides and physical and chemical behaviour. Nevertheless, research has demonstrated the importance of the correct SC lipid lamellar architecture with conformationally-ordered lipid bilayers, the presence of long-chain ceramides, as either free or covalently bound lipids, greater quantities of phytosphingosine-containing ceramides and a high SC lipid/protein ratio is essential for optimal barrier function. These features are known to change in a variety of physiological and pathophysiological conditions. Clearly, there is more to be learned but as we further decipher the complexity of SC lipids and understand their individual roles in the SC, we will learn how to better treat the disorders of cornification.

The rational design of biomimetic skin barrier lipid formulations using biophysical methods.

OBJECTIVE: The focus of this communication was to study phospholipid-structured emulsions whose phase behaviour is modified with monoalkyl fatty amphiphiles. Ideally, these systems would mimic key physical and structural attributes observed in human stratum corneum (SC) so that they better alleviate xerotic skin conditions. METHODS: Phosphatidylcholine-structured emulsions were prepared, and their phase behaviour modified with monoalkyl fatty amphiphiles. The effect of molecular volume, acyl chain length and head-group interactions was studied using a combination of physical methods. Water vapour transmission rate (WVTR) was used as a primary test to assess occlusive character. Changes in the vibrational modes observed in Fourier transform infrared (FTIR) spectroscopy and bilayer spacing measured by X-ray diffraction (XRD) were then applied to elucidate the lateral and lamellar microstructural characteristics in the systems. RESULTS: Water vapour transmission rate demonstrated that as the phosphatidylcholine acyl chain length increased from C14, to C18, to C22, there was a corresponding increase in occlusive character. The addition of monoalkyl fatty amphiphiles such as behenic acid, behenyl alcohol or cetostearyl alcohol to a base formulation incorporating dipalmitoyl and distearoylphosphatidylcholine (C18) was seen to further increase barrier characteristics of the emulsions. FTIR methods used to probe lipid-chain conformational ordering demonstrated that as phosphatidylcholine acyl chain lengths increased, there was a corresponding improvement in acyl chain ordering, with an increase in thermal transition temperatures. The addition of a monoalkyl fatty amphiphile resulted in conformational order and thermal transition temperature improvements trending towards those observed in stratum corneum. FTIR also demonstrated that systems containing behenic acid or behenyl alcohol exhibited features associated with orthorhombic character. X-ray diffraction data showed that addition of monoalkyl fatty amphiphile also resulted in thicker lamellar structures than when those agents are not present. CONCLUSION: The generalized approach described herein is shown to mechanistically describe the occlusive character of phospholipid-structured formulations in the presence of long-chain fatty acids or alcohols and that they exhibit characteristics mimicking those found in human SC lipids.

Lupus-Prone Mice Resist Immune Regulation and Transplant Tolerance Induction.

The strongly immunogenic environment in autoimmune diseases such as lupus may pose a stringent barrier to transplantation. Despite available murine models of lupus, transplant tolerance in this setting has yet to be fully investigated in highly penetrant genetic models of disease. Such studies are of clear clinical importance because lupus is a transplant indication in which transplanted kidneys have a substantially increased risk of rejection including a role for recurrent nephritis. In the fully penetrant B6.SLE123 mouse, we determined that CD4 T follicular helper and germinal center B cells were significantly expanded compared with healthy controls. We traced this expansion to resistance of effector CD4 T and B cells in B6.SLE123 mice to regulation by either CD4 T regulatory cells (CD4Tregs) or CD8 T regulatory cells (CD8Tregs), despite demonstrating normal function by Tregs in this strain. Finally, we determined that B6.SLE123 mice resist anti-CD45RB-mediated tolerance induction to foreign islet allografts, even in the absence of islet autoimmunity. Overall, B6.SLE123 lupus-prone mice are highly resistant to transplant tolerance induction, which provides a new model of failed tolerance in autoimmunity that may elucidate barriers to clinical transplantation in lupus through further cellular and genetic dissection.

The impact of ethnicity/race on the association between the Veterans Aging Cohort Study (VACS) Index and neurocognitive function among HIV-infected persons.

The Veterans Aging Cohort Study (VACS) Index was developed as a risk index for health outcomes in HIV, and it has been consistently associated with mortality. It shows a significant, yet relatively weak, association with neurocognitive impairment, and little is known about its utility among ethnic/racial minority groups. We examined whether the association between the VACS Index and neurocognition differed by ethnic/racial group. Participants included 674 HIV-infected individuals (369 non-Hispanic whites, 111 non-Hispanic blacks, and 194 Hispanics). Neurocognitive function was assessed via a comprehensive battery. Scaled scores for each neurocognitive test were averaged to calculate domain and global neurocognitive scores. Models adjusting for demographics and HIV disease characteristics not included in the VACS Index showed that higher VACS Index scores (indicating poorer health) were significantly associated with worse global neurocognition among non-Hispanic whites. This association was comparable in non-Hispanic blacks, but nonsignificant among Hispanics (with similar results for English and Spanish speaking). We obtained comparable findings in analyses adjusting for other covariates (psychiatric and medical comorbidities and lifestyle factors). Analyses of individual neurocognitive domains showed similar results in learning and delayed recall. For other domains, there was an effect of the VACS Index and no significant interactions with race/ethnicity. Different components of the VACS Index were associated with global neurocognition by race/ethnicity. In conclusion, the association between the VACS Index and neurocognitive function differs by ethnic/racial group. Identifying key indicators of HIV-associated neurocognitive impairment by ethnic/racial group might play an important role in furthering our understanding of the biomarkers of neuroAIDS.

Increased thrombin generation potential in symptomatic versus asymptomatic moderate or severe carotid stenosis and relationship with cerebral microemboli.

INTRODUCTION: The importance of thrombin generation in the pathogenesis of TIA or stroke and its relationship with cerebral microembolic signals (MES) in asymptomatic and symptomatic carotid stenosis has not been comprehensively assessed. METHODS: Plasma thrombin generation parameters from patients with moderate or severe (≥ 50%) asymptomatic carotid stenosis were compared with those from patients with symptomatic carotid stenosis in the early (≤ 4 weeks) and late phases (≥ 3 months) after TIA or stroke in this prospective, pilot observational study. Thrombin generation profile was longitudinally assessed in symptomatic patients with data at each time point. Bilateral transcranial Doppler ultrasound monitoring of the middle cerebral arteries was performed whenever possible to classify patients as MES-positive or MES-negative. RESULTS: Data from 31 asymptomatic, 46 'early symptomatic' and 35 'late symptomatic' patients were analysed. Peak thrombin (344.2 nM vs 305.3 nM; p = 0.01) and endogenous thrombin potential (1772.4 vs 1589.7; p = 0.047) were higher in early symptomatic than asymptomatic patients. Peak thrombin production decreased in symptomatic patients followed up from the early to late phase after TIA or stroke (339.7 nM vs 308.6 nM; p = 0.02). Transcranial Doppler ultrasound data were available in 25 asymptomatic, 31 early symptomatic and 27 late symptomatic patients. Early symptomatic MES-positive patients had a shorter 'time-to-peak thrombin' than asymptomatic MES-positive patients (p=0.04), suggesting a more procoagulant state in this early symptomatic subgroup. DISCUSSION: Thrombin generation potential is greater in patients with recently symptomatic than asymptomatic carotid stenosis, and decreases over time following TIA or stroke associated with carotid stenosis. These data improve our understanding of the haemostatic/thrombotic biomarker profile in moderate-severe carotid stenosis.

Increased endothelial activation in recently symptomatic versus asymptomatic carotid artery stenosis and in cerebral microembolic-signal-negative patient subgroups.

BACKGROUND AND PURPOSE: von Willebrand factor propeptide (VWF:Ag II) is potentially a more sensitive marker of acute endothelial activation than von Willebrand factor antigen (VWF:Ag). These biomarkers have not been simultaneously assessed in asymptomatic versus symptomatic carotid stenosis patients. The relationship between endothelial activation and cerebral microembolic signals (MESs) detected on transcranial Doppler ultrasound is unknown. METHODS: In this multicentre observational analytical study, plasma VWF:Ag and VWF:Ag II levels in patients with ≥50% asymptomatic carotid stenosis were compared with those from patients with ≥50% symptomatic carotid stenosis in the 'early' (≤4 weeks) and 'late' (≥3 months) phases after transient ischaemic attack or ischaemic stroke. Endothelial activation was also longitudinally assessed in symptomatic patients during follow-up. Transcranial Doppler ultrasound monitoring classified patients as MES-positive or MES-negative. RESULTS: Data from 31 asymptomatic patients were compared with those from 46 early symptomatic and 35 late phase symptomatic carotid stenosis patients, 23 of whom had undergone carotid intervention. VWF:Ag II levels were higher in early (12.8 µg/ml; P < 0.001), late (10.6 µg/ml; P = 0.01) and late post-intervention (10.6 µg/ml; P = 0.038) symptomatic patients than asymptomatic patients (8.9 µg/ml). VWF:Ag levels decreased in symptomatic patients followed up from the early to late phase after symptom onset (P = 0.048). Early symptomatic MES-negative patients had higher VWF: Ag II levels (13.3 vs. 9.0 µg/ml; P < 0.001) than asymptomatic MES-negative patients. CONCLUSIONS: Endothelial activation is enhanced in symptomatic versus asymptomatic carotid stenosis patients, in early symptomatic versus asymptomatic MES-negative patients, and decreases over time in symptomatic patients. VWF:Ag II levels are a more sensitive marker of endothelial activation than VWF:Ag levels in carotid stenosis. The potential value of endothelial biomarkers and concurrent cerebral MES detection at predicting stroke risk in carotid stenosis warrants further study.

The use of faecal microbiota transplant as treatment for recurrent or refractory Clostridioides difficile infection and other potential indications: second edition of joint British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS) guidelines.

The first British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS)-endorsed faecal microbiota transplant (FMT) guidelines were published in 2018. Over the past 5 years, there has been considerable growth in the evidence base (including publication of outcomes from large national FMT registries), necessitating an updated critical review of the literature and a second edition of the BSG/HIS FMT guidelines. These have been produced in accordance with National Institute for Health and Care Excellence-accredited methodology, thus have particular relevance for UK-based clinicians, but are intended to be of pertinence internationally. This second edition of the guidelines have been divided into recommendations, good practice points and recommendations against certain practices. With respect to FMT for Clostridioides difficile infection (CDI), key focus areas centred around timing of administration, increasing clinical experience of encapsulated FMT preparations and optimising donor screening. The latter topic is of particular relevance given the COVID-19 pandemic, and cases of patient morbidity and mortality resulting from FMT-related pathogen transmission. The guidelines also considered emergent literature on the use of FMT in non-CDI settings (including both gastrointestinal and non-gastrointestinal indications), reviewing relevant randomised controlled trials. Recommendations are provided regarding special areas (including compassionate FMT use), and considerations regarding the evolving landscape of FMT and microbiome therapeutics.

Memory-based strategies for antiretroviral medication management: an evaluation of clinical predictors, adherence behavior awareness, and effectiveness.

"Forgetting" is the most commonly endorsed reason for missing an antiretroviral therapy (ART) dose, yet little is known about the prevalence, predictors, and effectiveness of the mnemonic strategies to support ART adherence. The current study assessed 28 self-reported memory-based medication strategies in 233 HIV-infected individuals with 30-day ART adherence measured via the medication event monitoring system. Participants endorsed using multiple (8.7 ± 5.6) strategies with the most common being internally-driven. More frequent strategy use was uniquely associated with affective distress, dependent daily functioning, higher non-ART pill burden, and poorer ART adherence. Individuals who used strategies frequently, but perceived them as minimally effective, had more affective, physical, and functional distress. More frequent strategy use was associated with worse ART adherence and was unrelated to perceived effectiveness. Primary reliance on internally-based mnemonic strategies may reflect a lack of awareness of adherence behaviors and may be insufficient to support optimal ART adherence in vulnerable populations.

Diagnosing symptomatic HIV-associated neurocognitive disorders: self-report versus performance-based assessment of everyday functioning.

Three types of HIV-associated neurocognitive disorders (HAND) exist that are distinguished by presence and severity of impairment in cognitive and everyday functioning. Although well-validated neurocognitive measures exist, determining impairment in everyday functioning remains a challenge. We aim to determine whether Self-Report measures of everyday functioning are as effective in characterizing HAND as Performance-Based measures. We assessed 674 HIV-infected participants with a comprehensive neurocognitive battery; 233 met criteria for a HAND diagnosis by having at least mild neurocognitive impairment. Functional decline was measured via Self-Report and Performance-Based measures. HAND diagnoses were determined according to published criteria using three approaches to assess functional decline: (1) Self-Report measures only, (2) Performance-Based measures only, and (3) Dual-method combining Self-Report and Performance-Based measures. The Dual-method classified the most symptomatic HAND, compared to either singular method. Singular method classifications were 76% concordant with each other. Participants classified as Performance-Based functionally impaired were more likely to be unemployed and more immunosuppressed, whereas those classified as Self-Report functionally impaired had more depressive symptoms. Multimodal methods of assessing everyday functioning facilitate detection of symptomatic HAND. Singular Performance-Based classifications were associated with objective functional and disease-related factors; reliance on Self-Report classifications may be biased by depressive symptoms.

Spectrofluorescence of skin and hair.

There are numerous chromophores present throughout the strata of human skin, which present many challenges and opportunities to probe molecular events. Fluorescence spectroscopy is principally employed to identify important biochemical components of the skin including endogenous tryptophan, tyrosine, pepsin-digestible collagen cross-links, collagenase-digestible collagen cross-links, NADH, etc. Over the last 15 years, many advances in instrument technology have been introduced allowing for much faster data acquisition with spectrofluorometers. As a result, a series of spectrofluorescence emission scans can be generated for a range of excitation wavelengths, or vice versa (excitation scans for a range of emission wavelengths), quickly to generate excitation-emission matrices. In this work, we constructed an endogenous fingerprint of fluorescent compounds present in skin, hair and nail tissues by employing a range of excitation wavelengths from 270 to 450 nm with a resolution of 2 nm. As a result, we generated surface plots of fluorescence emission as a function of excitation and emission wavelengths. From these data, we identified the predominant fluorescent chromophores in each tissue. We examined several sources of skin including in vivo human and ex vivo pig, sheep, goat and cow skin. We also analysed various types of mature hair characterized by the degree of melanin content. These analyses provided us with a fundamental understanding of the effects of melanin distribution in hair fibres and aided with the identification of fluorophores present in hair.

Characterization of yield stress and slip behaviour of skin/hair care gels using steady flow and LAOS measurements and their correlation with sensorial attributes.

Gels made with three different polymers widely used as rheology modifiers in cosmetic formulations (cross-linked poly(acrylic acid), cross-linked poly(maleic acid-alt-methyl vinyl ether) copolymer and cross-linked poly(acrylic acid-co-vinyl pyrrolidone) copolymer) were characterized by rheological and sensory evaluation methods to determine the relationship between sensorial perception and corresponding rheological parameters. Both conventional rheological characterization methods and a more recent method, Fourier Transform Rheology with Large Amplitude Oscillatory Flow data (LAOS), were utilized to characterize the material with and without wall slip. Sensorial analyses were implemented in vivo to evaluate the perceived ease of initial and rub-out spreadability, cushion, pick-up and slipperiness attributes of the gels. Results were statistically analysed by both variance (ANOVA) and principle component analysis (PCA). Sensorial panel testing characteristics discriminated the three materials, and PCA analyses revealed that sensory attributes could be well predicted by rheological methods. Rheological experiments, without wall slip, revealed that gel strength in the linear viscoelastic region (LVR) and yield stress of these materials are similar, but exhibit significantly different wall slip and thixotropy behaviour in the low shear rate region under wall slip conditions. Above the critical shear rate, which corresponds to the yield stress, all tested materials did not slip and behaved as conventional, shear thinning polymeric fluids. In particular, the rheological parameters and sensorial perception of the 1% cross-linked vinyl pyrrolidone/acrylic acid copolymer were significantly affected by wall slip and/or thixotropy-related shear banding phenomena.

A primer for data assimilation with ecological models using Markov Chain Monte Carlo (MCMC).

Data assimilation, or the fusion of a mathematical model with ecological data, is rapidly expanding knowledge of ecological systems across multiple spatial and temporal scales. As the amount of ecological data available to a broader audience increases, quantitative proficiency with data assimilation tools and techniques will be an essential skill for ecological analysis in this data-rich era. We provide a data assimilation primer for the novice user by (1) reviewing data assimilation terminology and methodology, (2) showcasing a variety of data assimilation studies across the ecological, environmental, and atmospheric sciences with the aim of gaining an understanding of potential applications of data assimilation, and (3) applying data assimilation in specific ecological examples to determine the components of net ecosystem carbon uptake in a forest and also the population dynamics of the mayfly (Hexagenia limbata, Serville). The review and examples are then used to provide guiding principles to newly proficient data assimilation practitioners.

The effect of various cosmetic pretreatments on protecting hair from thermal damage by hot flat ironing.

Hot flat irons are used to create straight hair styles. As these devices operate at temperatures over 200 °C they can cause significant damage to hair keratin. In this study, hair thermal damage and the effect of various polymeric pretreatments were investigated using FTIR imaging spectroscopy, DSC, dynamic vapor sorption (DVS), AFM, SEM, and thermal image analysis. FTIR imaging spectroscopy of hair cross sections provides spatially resolved molecular information such as protein distribution and structure. This approach was used to monitor thermally induced modification of hair protein, including the conversion of α-helix to ß-sheet and protein degradation. DSC measurements of thermally treated hair also demonstrated degradation of hair keratin. DVS of thermally treated hair shows the reduced water regain and lower water retention, compared to the non-thermally treated hair, which might be attributed to the protein conformation changes due to heat damage. The protection of native protein structure associated with selected polymer pretreatments leads to improved moisture restoration and water retention of hair. This contributes to heat control on repeated hot flat ironing. Thermally stressing hair led to significantly increased hair breakage when subjected to combing. These studies indicate that hair breakage can be reduced significantly when hair is pretreated with selected polymers such as VP/acrylates/lauryl methacrylate copolymer, polyquaternium-55, and a polyelectrolyte complex of PVM/MA copolymer and polyquaternium-28. In addition, polymeric pretreatments provide thermal protection against thermal degradation of keratin in the cortex as well as hair surface damage. The morphological improvement in cuticle integrity and smoothness with the polymer pretreatment plays an important role in their anti-breakage effect. Insights into structure-property relationships necessary to provide thermal protection to hair are presented.