Multi-omics approach to understand the impact of sun exposure on an in vitro skin ecosystem and evaluate a new broad-spectrum sunscreen

A reconstructed human epidermal model (RHE) colonized with human microbiota and sebum was developed to reproduce the complexity of the skin ecosystem in vitro. The RHE model was exposed to simulated solar radiation (SSR) with or without SPF50+ sunscreen (with UVB, UVA, long-UVA, and visible light protection). Structural identification of discriminant metabolites was acquired by nuclear magnetic resonance and metabolomic fingerprints were identified using reverse phase-ultra high-performance liquid chromatography-high resolution mass spectrometry, followed by pathway enrichment analysis. Over 50 metabolites were significantly altered by SSR (p < 0.05, log2 values), showing high skin oxidative stress (glutathione and purine pathways, urea cycle) and altered skin microbiota (branched-chain amino acid cycle and tryptophan pathway). 16S and internal transcribed spacer rRNA sequencing showed the relative abundance of various bacteria and fungi altered by SSR. This study identified highly accurate metabolomic fingerprints and metagenomic modifications of sun-exposed skin to help elucidate the interactions between the skin and its microbiota. Application of SPF50+ sunscreen protected the skin ecosystem model from the deleterious effects of SSR and preserved the physiological interactions within the skin ecosystem. These innovative technologies could thus be used to evaluate the effectiveness of sunscreen.

A Comprehensive Comparison of Tissue Processing Methods for High-Quality MALDI Imaging of Lipids in Reconstructed Human Epidermis

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) has become an important tool for skin analysis, as it allows the simultaneous detection and localization of diverse molecular species within a sample. The use of in vivo and ex vivo human skin models is costly and presents ethical issues; therefore, reconstructed human epidermis (RHE) models, which mimic the upper part of native human skin, represent a suitable alternative to investigate adverse effects of chemicals applied to the skin. However, there are few publications investigating the feasibility of using MALDI MSI on RHE models. Therefore, the aim of this study was to investigate the effect of sample preparation techniques, i.e., substrate, sample thickness, washing, and matrix recrystallization, on the quality of MALDI MSI for lipids analysis of the SkinEthic RHE model. Images were generated using an atmospheric pressure MALDI source coupled to a high-resolution mass spectrometer with a pixel size of 5 μm. Masses detected in a defined region of interest were analyzed and annotated using the LipostarMSI platform. The results indicated that the combination of (1) coated metallic substrates, such as APTES-coated stainless-steel plates, (2) tissue sections of 6 μm thickness, and (3) aqueous washing before HCCA matrix spraying (without recrystallization), resulted in images with a significant signal intensity as well as numerous m/z values. This refined methodology using AP-MALDI coupled to a high-resolution mass spectrometer should improve the current sample preparation workflow to evaluate changes in skin composition after application of dermatocosmetics.

Evaluation of a novel skin emollient cream on skin lipidome and lipids organization

INTRODUCTION

The stratum corneum (SC) matrix is composed of free fatty acids, cholesterol and ceramides (CERs), which play a key role in the skin barrier function. Changes in the composition and content of skin lipids will affect the function of the skin barrier. The effect of a glycerol/petrolatum-based emollient (G/P-emollient) cream on the lipid profiles of isolated ex vivo human SC and the SC of a reconstructed human epithelial (RHE) model were measured.

METHODS

The spatial organization of the cream and the isolated SC intercellular matrix was studied using X-ray diffraction. The inter-bilayer distance in the multi-lamellar lipid structures and lattice type were analyzed using small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS), respectively. Lipidomic analysis using Shotgun Lipidomics was performed on reconstructed human epidermis (RHE) to quantify CER classes and chain lengths. This technology enables the analysis of thousands of lipids in a single biological sample.

RESULTS

The crystallized components of the cream are lipids, which were mainly packed in orthorhombic lattices, as well as hexagonal lattices and were similar to the SC structure. The cream penetrated the SC but did not alter the WAXS profile. It increased the amount of higher carbon number ceramides (> 42 carbons) and decreased lower carbon number ceramides (<42 carbons). All chain length acyl-CERs and acyl-CER classes (CER EOS, EOH, EOP, EOdS) were increased as the total CER classes. A decrease of the CER C34 for hydroxylated and non-hydroxylated CERs was also observed. The cream altered the [S] and [P] CER forms (increased the [NP]/[NS] and [AP]/[AS] ratios), indicating it could reduce the relative feedback mechanism observed in inflammatory pathologies e.g., atopic dermatitis. The cream increased CER[NP], which is decreased in dry skin.

CONCLUSION

G/P-emollient cream may be beneficial for skin pathologies by modifying SC lipids, balancing CER levels and ratios, and improving the barrier function. Importantly, the cream structure mimics that of the SC and penetrated the lower SC layers without compromising its lamellar structure.

Development of a microphysiological skin-liver-thyroid Chip3 model and its application to evaluate the effects on thyroid hormones of topically applied cosmetic ingredients under consumer-relevant conditions

All cosmetic ingredients registered in Europe must be evaluated for their safety using non-animal methods. Microphysiological systems (MPS) offer a more complex higher tier model to evaluate chemicals. Having established a skin and liver HUMIMIC Chip2 model demonstrating how dosing scenarios impact the kinetics of chemicals, we investigated whether thyroid follicles could be incorporated to evaluate the potential of topically applied chemicals to cause endocrine disruption. This combination of models in the HUMIMIC Chip3 is new; therefore, we describe here how it was optimized using two chemicals known to inhibit thyroid production, daidzein and genistein. The MPS was comprised of Phenion^® Full Thickness skin, liver spheroids and thyroid follicles co-cultured in the TissUse HUMIMIC Chip3. Endocrine disruption effects were determined according to changes in thyroid hormones, thyroxine (T₄) and 3,3',5-triiodothyronine (T₃). A main part of the Chip3 model optimization was the replacement of freshly isolated thyroid follicles with thyrocyte-derived follicles. These were used in static incubations to demonstrate the inhibition of T₄ and T₃ production by genistein and daidzein over 4 days. Daidzein exhibited a lower inhibitory activity than genistein and both inhibitory activities were decreased after a 24 h preincubation with liver spheroids, indicating metabolism was via detoxification pathways. The skin-liver-thyroid Chip3 model was used to determine a consumer-relevant exposure to daidzein present in a body lotion based on thyroid effects. A "safe dose" of 0.235 μg/cm² i.e., 0.047% applied in 0.5 mg/cm² of body lotion was the highest concentration of daidzein which does not result in changes in T₃ and T₄ levels. This concentration correlated well with the value considered safe by regulators. In conclusion, the Chip3 model enabled the incorporation of the relevant exposure route (dermal), metabolism in the skin and liver, and the bioactivity endpoint (assessment of hormonal balance i.e., thyroid effects) into a single model. These conditions are closer to those in vivo than 2D cell/tissue assays lacking metabolic function. Importantly, it also allowed the assessment of repeated doses of chemical and a direct comparison of systemic and tissue concentrations with toxicodynamic effects over time, which is more realistic and relevant for safety assessment.

Miniaturized Two-Dimensional Heart Cutting for LC-MS-Based Metabolomics

Liquid chromatography-mass spectrometry (LC-MS)-based metabolomics usually combines hydrophilic interaction liquid chromatography (HILIC) and reversed-phase (RP) chromatography to cover a wide range of metabolomes, requiring both significant sample consumption and analysis time for separate workflows. We developed an integrated workflow enabling the coverage of both polar and nonpolar metabolites with only one injection of the sample for each ionization mode using heart-cutting trapping to combine HILIC and RP separations. This approach enables the trapping of some compounds eluted from the first chromatographic dimension for separation later in the second dimension. In our case, we applied heart-cutting to non-retained metabolites in the first dimension. For that purpose, two independent miniaturized one-dimensional HILIC and RP methods were developed by optimizing the chromatographic and ionization conditions using columns with an inner diameter of 1 mm. They were then merged into one two-dimensional micro LC-MS method by optimization of the trapping conditions. Equilibration of the HILIC column during elution on the RP column and vice versa reduced the overall analysis time, and the multidimensionality allows us to avoid signal measurements during the solvent front. To demonstrate the benefits of this approach to metabolomics, it was applied to the analysis of the human plasma standard reference material SRM 1950, enabling the detection of hundreds of metabolites without the significant loss of some of them while requiring an injection volume of only 0.5 μL.

P-787 Factors associated with live birth rate (LBR) and multiple live birth rate (mLBR): UK vs France registries

Study question

Do the associations between age, previous attempts, frozen and day-5 transfers relative to LBR and mLBR differ between national registries (UK vs France)?

Summary answer

Both registries agree age negatively correlates with LBR and mLBR; disagree on effects of frozen transfers, previous attempts and day-5 transfers on LBR and mLBR.

What is known already

Due to the high risks of multiple pregnancy, the focus of ART success was shifted from having a high number of live birth rate (LBR) to one full-term, healthy baby and a low multiple live birth rate (mLBR). Elective single embryo transfer (eSET) has been an effective strategy for reducing the risk of mLBR but in most guidelines, it is recommended for young patients (&lt;35 years) only. There is extensive evidence from large-scale studies characterising how factors, seen in eSET policies, affect LBR. However, only a few studies focus on mLBR.

Study design, size, duration

A retrospective analysis of two national registry datasets, HFEA (UK) (N = 442042; 2014-2018) and ABM (France) (N = 305142; 2014-2018), evaluating how age (&lt;35 yrs, 35-37 yrs, 38-40 yrs, &gt;41 yrs), fresh/frozen embryo transfer (ET), previous attempts (0, 1, 2, 3, 4, 5 attempts), and embryo stage (day-5 or day-3 transfers) impact LBR and mLBR following eSET (control group) and multiple embryo transfer (MET) (treatment group).

Participants/materials, setting, methods

Statistical analyses of the datasets were conducted using adjusted two-sided odds ratios from chi-squared tests with 95% confidence intervals (α = 0.05) with Bonferroni correction.

Main results and the role of chance

Two registries agreed on the negative correlation between age and LBR (HFEA: eSET OR:1.00-0.79-0.73-0.57, p &lt; 0.001; MET OR:1.00-0.85-0.74-0.55, p &lt; 0.001; ABM: eSET OR:1.00-0.75-0.71-0.52, p &lt; 0.001; MET OR:1.00-0.80-0.69-0.50, p &lt; 0.001) and mLBR following MET (HFEA OR:1.00-0.79-0.70-0.71, p &lt; 0.001; ABM OR:1.00-0.74-0.74-0.59, p &lt; 0.001). mLBR following eSET remained constant with increasing age in both datasets (HFEA OR:1.00-0.91-0.92-1.34, NS; ABM OR:1.00-0.87-1.02-1.13, NS). LBR was significantly higher for fresh vs frozen eSET in both datasets (HFEA OR:1.36, p &lt; 0.001; ABM OR:1.83, p &lt; 0.001). However, HFEA showed no significant difference in LBR between fresh and frozen MET (OR:0.98, NS), whereas LBR in fresh MET was significantly higher in ABM (OR:1.28, p &lt; 0.001). There was disagreement on fresh vs frozen ET mLBR (HFEA: eSET OR:1.10, NS; MET OR:0.97, NS; ABM: eSET OR:0.81, p &lt; 0.05; MET OR:1.36, p &lt; 0.001). Registry results differed regarding the impact of previous attempts on LBR and mLBR.Day-5 ETs had significantly higher LBR compared to day-3 (HFEA eSET OR:1.29, p &lt; 0.001; MET OR:1.37, p &lt; 0.001; ABM: eSET OR:1.50, p &lt; 0.001; MET OR:1.35, p &lt; 0.001). mLBR was significantly higher following day-5 MET (HFEA OR:1.59, p &lt; 0.001; ABM OR:1.27, p &lt; 0.001) but only significantly higher following eSET in the French registry (HFEA OR:0.64, NS; ABM OR:1.40, p &lt; 0.01).

Limitations, reasons for caution

Limitations included selection bias due to the retrospective design of the study, as a result, the populations include predominantly caucasian, European populations. The conclusions drawn relate to the practices from particular countries, so it is important to evaluate multiple, more diverse datasets.

Wider implications of the findings

It is encouraging that both registries agreed on the effects of age, whilst remaining factors were not generalizable and require further assessment. This study demonstrated that even large, national registries contain inherent biases and policymakers should not draw policies based on one dataset, especially when prospective trial is not feasible.

Trial registration number

N/A

O-177 Towards 3D Reconstructions of Human Preimplantation Embryo Development

Study question

Can we use focal stacks collected through Hoffman modulation contrast (HMC) microscopy to generate 3D reconstructions of preimplantation embryos?

Summary answer

A machine learning system was designed to generate 3D meshes that approximate the structures of embryos captured on HMC microscopes up to the 8-cell stage. 

What is known already

The 3D arrangement of cells in preimplantation human embryos is a topic of clinical interest, with significant associations between the cell arrangement and blastulation potential from as early as the 4-cell stage. In basic research, the use of confocal microscopy for generating 3D reconstructions is commonplace. However, the use of confocal microscopy in the IVF clinic is often infeasible due to cost and concerns for embryos’ wellbeing. The assessment of 3D cell arrangement in clinical settings can thus prove difficult and time-consuming as many embryologists rely on focal stacks captured through the HMC microscopes widely integrated into incubators. 

Study design, size, duration

The study was a retrospective analysis of 581 Embryoscope focal stacks of embryos from 4 clinics collected between 2018 and 2020. The number of planes in each stack ranged from 7-11 and cell outlines were annotated along with the depths at which they were most in-focus. A deep learning system was designed to generate 3D reconstructions of the embryos. Two clinics’ data were used for training (N = 551) and the others’ for evaluation (N = 30).

Participants/materials, setting, methods

The deep learning system consisted of three stages: a super-resolution module, a cell segmentation module and a depth regression module. The super-resolution stage was used to predict missing planes in focal stacks that did not contain 11 focal planes; the segmentation module identified individual cells; the depth regression module identified the focal plane at which each cell was most “in-focus”. Meshes were then generated under the assumption that blastomeres’ dimensions are similar along each axis.

Main results and the role of chance

The superresolution module was evaluated by calculating the structural similarity index (SSIM; an image similarity measure ranging from 0-1) between predicted and true planes when tasked with predicting missing frames in focal stacks with up to 4 planes artificially removed (by uniform random sampling). The module achieved an SSIM of 0.80. The predictions were also evaluated by 2 embryologists, a clinician and a developmental biologist on a scale of 1-5 (1=very unrealistic; 3=usable; 5=very realistic), achieving a mean score of 4.11.

The segmentation module was evaluated on the proportion of cells it managed to identify (91%) as well as the mean overlap between predicted cell segmentations and the ground truth (intersection-over-union of 0.86). The depth module was evaluated on the mean deviation of predictions from the true most “in-focus” plane (0.73 planes).

3D reconstructions generated by the system were evaluated with reference to the original focal stacks by 2 embryologists on a 1-5 scale similar to before, with a mean score of 3.72. The most common issues with the reconstructions identified by the embryologists were missing cells/fragments, incorrect cell shape due to obstruction by the well’s edge and imprecise depth predictions (with the “true” depth being between focal planes).

Limitations, reasons for caution

As previously mentioned, some reconstructions had inaccuracies. These would likely be ameliorated through modifications to the system modules and more training data. Moreover, the system was not trained or evaluated on morulae/blastocysts. Finally, each focal stack was analysed independently - future work may examine enforcing temporal consistency within timelapses. 

Wider implications of the findings

This work serves as a first step towards unlocking data captured in IVF clinics for research into cell arrangement in preimplantation embryos. Combined with cell tracking, the system may be useful for research into cell fate. Moreover, the work may find clinical relevance in enabling easier assessment of cell arrangement.

Trial registration number

N/A

P-281 A multi-centre evaluation of a novel 4-cell embryo classification system based on intercellular contact points

Study question

Is there any prognostic value to classifying 4-cell embryos according to intercellular contact points (ICPs)?

Summary answer

A significant association was found between the new blastomere arrangement classifications and blastulation, as well as blastocyst quality. No significant association was found for pregnancy.

What is known already

Current literature states that the geometric arrangement of blastomeres in 4-cell embryos is usually classified as either “tetrahedral” or “non-tetrahedral/planar”. Though tetrahedral embryos have been associated with greater developmental capacity, their prevalence has varied between studies. At ESHRE 2021, Hickman et al. proposed a more fine-grained classification system; each class was associated with a 4-digit code, where the Nth digit in said code gave the number of cells with N-1 ICPs. This gave rise to 6 classes: tetrahedral (0004), pseudotetrahedral (0022), planar (0040), closed-Y (0121), open-Y (0301) and linear (0220). In our study, we evaluate this new system.

Study design, size, duration

This study was a retrospective analysis of 844 4-cell embryos across 3 clinics in 3 countries. Focal stacks of the embryos were captured on Embryoscope/MIRI time-lapse incubators between 2018 and 2020. Embryos were annotated by their respective clinics using the original “tetrahedral/planar” system. Additionally, data on blastulation, blastocyst grade (Gardner scale) and biochemical pregnancy rates were obtained for each embryo.

Participants/materials, setting, methods

The embryos were annotated according to the new system by a panel of three researchers without knowledge of the clinics’ or each other’s classifications. Afterwards, the panelists assembled for discussion and a unanimous consensus was reached for each embryo. The cell arrangement classes were analysed with respect to blastulation rates, blastocyst grade and pregnancy rates using chi-squared tests. The distribution of classes across the clinics was also analysed, as well as agreement among the panelists.

Main results and the role of chance

Under the new system, tetrahedral and pseudotetrahedral embryos saw significantly higher rates of blastulation (P = 0.017) and good-quality blastocysts (p = 0.043; here, “good-quality” means that the grade contains no ‘C’s or numbers less than 3) compared to other arrangements. No association was found with respect to biochemical pregnancy (p = 0.77).

There was significant variation between the clinic-provided classifications (p &lt; 0.001) with tetrahedral-to-planar ratios ranging from 1 to 9. Under the new system, there was no significant difference between the proportions of each arrangement (p = 0.66). The arrangements in order of decreasing prevalence across all the data were tetrahedral (63.7%), pseudotetrahedral (25.8%), planar (8.0%), closed-Y (2.2%) and linear (0.3%). No open-Y embryos were observed. Upon comparison with the clinic-provided tetrahedral/planar classifications, there were clear differences in the treatment of pseudotetrahedral embryos - some clinics predominantly classified them as “tetrahedral” while others as “planar”.

Prior to any discussions, the panelists’ annotations unanimously agreed on the classifications of 63% of the embryos; with 33% of the embryos having 2 different classifications and 4% of embryos causing total disagreement. The majority of disagreements regarded pseudotetrahedral embryos being confused for either tetrahedral or planar embryos.

Limitations, reasons for caution

It can be at times difficult to visualise the 3D structure of embryos from focal stacks. As a result, some annotations may be erroneous, though the use of a panel-based approach helped to mitigate this. Moreover, further studies will need to take place to validate the findings in this work.

Wider implications of the findings

The findings demonstrate the prognostic utility of Hickman et al.’s ICP-based classification system. Moreover, the findings suggest that much of the variability seen in the prevalence of tetrahedral embryos under the tetrahedral/planar system came from the mislabelling of pseudotetrahedral embryos which comprised 25.8% of the study population.

Trial registration number

N/A

MS imaging and absorption methods visualizing sun filter skin spatial distribution and penetration

Sunscreens must now be effective in protecting skin from ultraviolet, as well as visible/infrared radiation. Here, TriAsorB, a new broad-spectrum sun filter, was formulated with three other sunscreens and their distribution on human skin was studied using a standard penetration protocol and two novel mass spectrometry imaging techniques: atmospheric pressure matrix assisted laser desorption ionization (AP-MALDI) coupled to high resolution mass spectrometry and time of flight - secondary ion mass spectrometry (ToF-SIMS). The standard penetration protocol showed that sun filters absorption was very low, with most of the dose recovered at the surface (none entered the receptor fluid). Absorption was not increased in damaged skin. The results were confirmed by AP-MALDI and ToF-SIMS imaging of the spatial distribution of molecular species in cross-section samples of human skin. Each sun filter was detected on or in the stratum corneum, with a good homogenous coverage over the valleys and peaks of the skin, and correlated well with the distribution of endogenous biomarkers. In conclusion, conventional and novel imaging analysis methods showed that the sun filters remained mainly on the skin surface after topical application. Mass spectrometry imaging is a promising complementary approach to traditional skin penetration studies to visualize penetration of compounds.

In vitro characterization and clinical evaluation of skin hydration by two formulations mimicking the skin's natural components

BACKGROUND

We have developed innovative base formulations that were designed to mimic the skin with respect to its components and galenic structure. Components include water, proteins, lipids, sugars and minerals.

OBJECTIVES

We characterized formulations and their skin penetration using in vitro methods and evaluated their impact on skin hydration in a clinical trial.

METHODS

Scanning electron microscopy (SEM) imaging and X-ray diffraction were used to analyse formulations as well as formulation impact on the stratum corneum (SC) structure. Mass spectrometry imaging (MSI) was used to compare formulation ingredients with SC components and to detect their distribution in the skin. Clinical studies were performed to confirm effects on skin hydration and investigate potential adverse skin effects (irritation and sensitization).

RESULTS

SEM and X-ray diffraction of the formulations showed that lipids were organized in sheets similar to SC lipids. MSI demonstrated similarities between formulation components and skin constituents, as well as a good penetration into the skin. The formulations did not modify the lamellar organization of the SC lipids, but they increased the relative proportion of the crystallized lipids and some of the amorphous lipids. In in vivo studies, a high level of hydration was maintained over 24 h after application with an intense and 'very good hydration'. Both formulations were shown to be non-(photo)sensitizers with excellent tolerance. Sensorial evaluation indicated the formulations were not oily or sticky and maintained the skin's suppleness over time. Formulations had a 'nude skin' touch and created a natural protective film.

CONCLUSIONS

The two formulations were well-tolerated and increased skin hydration in clinical subjects, an effect that could contribute to the alleviation of sensitive skin. The formulations were shown to resemble the lipid organization of the stratum corneum, as well as penetrate the skin without disrupting the lipid lamella organization.

Liraglutide, a glucagon-like peptide 1 receptor agonist, exerts analgesic, anti-inflammatory and anti-degradative actions in osteoarthritis

Osteoarthritis (OA) is a common disabling disease worldwide, with no effective and safe disease-modifying drugs (DMOAD) in the market. However, studies suggest that drugs, such as liraglutide, which possess strong potential in decreasing low-grade systemic inflammation may be effective in treating OA. Therefore, the aim of this study was to examine the anti-inflammatory, analgesic, and anti-degradative effects in OA using in vitro and in vivo experiments. The results showed that intra-articular injection of liraglutide alleviated pain-related behavior in in vivo sodium monoiodoacetate OA mouse model, which was probably driven by the GLP-1R-mediated anti-inflammatory activity of liraglutide. Moreover, liraglutide treatment significantly decreased IL-6, PGE₂ and nitric oxide secretion, and the expression of inflammatory genes in vitro in chondrocytes and macrophages in a dose-dependent manner. Additionally, liraglutide shifted polarized macrophage phenotype in vitro from the pro-inflammatory M1 phenotype to the M2 anti-inflammatory phenotype. Furthermore, liraglutide exerted anti-catabolic activity by significantly decreasing the activities of metalloproteinases and aggrecanases, a family of catabolic enzymes involved in cartilage breakdown in vitro. Overall, the findings of this study showed that liraglutide ameliorated OA-associated pain, possess anti-inflammatory and analgesic properties, and could constitute a novel therapeutic candidate for OA treatment.

Targeting the GLP-1/GLP-1R axis to treat osteoarthritis: A new opportunity?

Osteoarthritis (OA) is a degenerative joint disease affecting millions of people worldwide. In OA, chondrocytes, synovial cells and other joint cells become activated when exposed to an abnormal environment, including mechanical stress, inflammatory cytokines or disorganization of matrix proteins. Several analogues of the hormones called incretins have been developed and are used notably for treating type 2 diabetes mellitus. Data has accumulated to suggest that incretinomimetics, which bind to the glucagon-like peptide-1 receptor (GLP-1R), have beneficial pleiotropic effects such as immunomodulation, anti-inflammation and neuronal protection. Thus, because of their anti-inflammatory properties, GLP-1-based therapies could benefit OA patients. This review focuses on the GLP-1R pathway, molecular mechanisms and phenotypes related to OA pathogenesis.

The translational potential of this article

The search for new therapeutic targets to treat people suffering from OA remains urgent as there is currently no disease-modifyingtherapy available for this disease. This review discusses how GLP-1 analogues could be potential DMOADs for treating OA thanks to their anti-inflammatory, immunoregulatory and differentiation properties.

Ascorbic acid 2-glucoside: An ascorbic acid pro-drug with longer-term antioxidant efficacy in skin

OBJECTIVE

Deleterious effects of pollutants and ultraviolet radiation on the skin can be attenuated using formulations containing antioxidants. However, these have disadvantages, including chemical instability, photodegradation, poor bioavailability or biological activity. Here, two commercial formulations were evaluated: one optimized to stabilize and deliver ascorbic acid (AA) at 15% and the other containing a glucoside form of AA, namely ascorbic acid 2-glucoside (AA2G), at 1.8% and at a physiological pH. We compared the skin delivery, antioxidative effects and chemical stability of AA2G with AA in their respective formulations.

METHODS

Skin delivery was measured using fresh viable human skin explants, and oxidative stress was measured using a human reconstructed epidermal (RHE) model according to levels of malondialdehyde (MDA), superoxide dismutase (SOD) and catalase.

RESULTS

Ascorbic acid 2-glucoside was completely metabolized to AA by the skin before entering the receptor compartment. The skin contained parent and AA, indicating a reserve of AA2G was present for further metabolism. For AA2G and AA, maximum flux of AA-equivalents was at 12 h, with continued absorption over 24 h. The absolute amount in µg was higher in the skin after application of AA than after application of AA2G. This may suggest a greater antioxidative effect; however, according to all three measurements of oxidative stress, the protective effect of AA and AA2G was similar. Unlike AA, AA2G was chemically stable under storage conditions.

CONCLUSION

A lower concentration of AA2G is as effective as the active metabolite, AA, in terms of antioxidant effects. AA2G was chemically stable and can be applied at a lower concentration than AA, thus avoiding the need for an acidic formulation with a pH below 3.5.

P–535 Machine learning classification algorithms can predict the ploidy status on day 5 and 6 with a 79% accuracy using evolutive morphological parameters and patient age

Study question

Can Machine Learning predict ploidy status from embryo evolutive morphological parameters in a non intrusive way?

Summary answer

Reporting cumulative embryo scoring from early development days and feed it to machine learning algorithms can help better predict the ploidy status of embryos

What is known already

Wiemer and Kelley showed morphological parameters and development rates were important parameters to consider during the embryo transfer process. Minasi et al. showed morphology assessment at blastocyst stage was correlated with ploidy status. Chavez-Badiola et al. showed a deep learning algorithm could predict the embryos ploidy with an accuracy of 70% and with positive predictive value of 0.79 using labeled blastocysts images.

Study design, size, duration

Study was a retrospective cohort analysis from 2019 to 2020 of 2520 biopsied embryos (669 cycles) cultured at POMA fertility clinic. Observations included all autologous embryos undergoing PGTA on day 5 or 6 with known PGTA status. Embryos from donors and with undefined PGTA results were excluded from the study. The embryos were classified as either euploid (n = 1528) or displaying a chromosomal anomaly (n = 992)

Participants/materials, setting, methods

Input of the machine learning model included patient age and 19 morphological parameters collected on days 1, 2, 3, 5 and 6 (symmetry, number of cells, blastocyst status, fragmentation, ICM and troph grades). An xgboost algorithm was trained on 80% of the data (n = 2016) and tested on 20% of blind data (n = 504).

Main results and the role of chance

Xgboost machine learning algorithm managed to predict ploidy status on the blind dataset with an accuracy of 79%, significantly higher than random chance (AUC= 0.71) and a positive predictive value of 87%.

Blastocyst stage parameters that are usually monitored to assess embryo quality (ICM, troph and blastocyst status on days 5 and 6) ranked high in the predictive power of the machine learning algorithm. It appeared that despite moderate to small individual correlation with the ploidy status, including parameters on day 1 (including number of PNs and number of cells on day1 PM check) to day 3 increased the performance of the classification algorithm from 70% accuracy to 79% accuracy. Machine learning algorithms are able to exploit evolution of morphological parameters during the development to improve the prediction.

Limitations, reasons for caution

Dataset was derived from one single clinic with manual annotations. Results should be validated on more clinics and inter-operator variation in morphological parameters annotation should be assessed to confirm robustness of the model and increase its predictive power.

Wider implications of the findings: Study shows the potential of detecting ploidy status in a non intrusive way and participating to embryo selection. Study confirms the importance of annotating morphological parameters of embryos in the early days of development.

Trial registration number

Not applicable

P–165 Using Artificial Intelligence to Classify Embryo Shape: An International Perspective

Study question

Is a pre-trained machine learning algorithm able to accurately detect cellular arrangement in 4-cell embryos from a different continent?

Summary answer

Artificial Intelligence (AI) analysis of 4-cell embryo classification is transferable across clinics globally with 79% accuracy.

What is known already

Previous studies observing four-cell human embryo configurations have demonstrated that non-tetrahedral embryos (embryos in which cells make contact with fewer than 3 other cells) are associated with compromised blastulation and implantation potential. Previous research by this study group has indicated the efficacy of AI models in classification of tetrahedral and non-tetrahedral embryos with 87% accuracy, with a database comprising 2 clinics both from the same country (Brazil). This study aims to evaluate the transferability and robustness of this model on blind test data from a different country (France).

Study design, size, duration

The study was a retrospective cohort analysis in which 909 4-cell embryo images (“tetrahedral”, n = 749; “non-tetrahedral”, n = 160) were collected from 3 clinics (2 Brazilian, 1 French). All embryos were captured at the central focal plane using Embryoscope™ time-lapse incubators. The training data consisted solely of embryo images captured in Brazil (586 tetrahedral; 87 non-tetrahedral) and the test data consisted exclusively of embryo images captured in France (163 tetrahedral; 72 non-tetrahedral).

Participants/materials, setting, methods

The embryo images were labelled as either “tetrahedral” or “non-tetrahedral” at their respective clinics. Annotations were then validated by three operators. A ResNet–50 neural network model pretrained on ImageNet was fine-tuned on the training dataset to predict the correct annotation for each image. We used the cross entropy loss function and the RMSprop optimiser (lr = 1e–5). Simple data augmentations (flips and rotations) were used during the training process to help counteract class imbalances.

Main results and the role of chance

Our model was capable of classifying embryos in the blind French test set with 79% accuracy when trained with the Brazilian data. The model had sensitivity of 91% and 51% for tetrahedral and non-tetrahedral embryos respectively; precision was 81% and 73%; F1 score was 86% and 60%; and AUC was 0.61 and 0.64. This represents a 10% decrease in accuracy compared to when the model both trained and tested on different data from the same clinics.

Limitations, reasons for caution

Although strict inclusion and exclusion criteria were used, inter-operator variability may affect the pre-processing stage of the algorithm. Moreover, as only one focal plane was used, ambiguous cases were interpoloated and further annotated. Analysing embryos at multiple focal planes may prove crucial in improving the accuracy of the model.

Wider implications of the findings: Though the use of machine learning models in the analysis of embryo imagery has grown in recent years, there has been concern over their robustness and transferability. While previous results have demonstrated the utility of locally-trained models, our results highlight the potential for models to be implemented across different clinics.

Trial registration number

Not applicable

P–378 Using a machine learning tool (72% accuracy with 64% PPV) to predict multiple live birth when transferring multiple embryos, based on embryo specific data

Study question

Can Machine Learning predict multiple pregnancy based on data specific to the embryos and the patient?

Summary answer

Embryo data are useful in determining which embryos are likely to lead to multiple pregnancy. Patient age has low predictive value compared to embryo data.

What is known already

Our previous assessment of the HFEA data demonstrated that single embryo transfer (SET) in the UK occurred in a minority (45%) of fresh cycles, with a marginal increase in live birth rate (LBR) in some patient cohorts in favor of multiple embryo transfer (MET). Current policies on determining number of embryos for transfer tend to be generic and do not account for detailed embryology data. Generic policies may compromise LBR for some patients that would benefit from MET. Artificial Intelligence has the potential to assist in this decision process.

Study design, size, duration

Retrospective cohort analysis from 2013 to 2020 of 193 cycles with 386 embryos used in double ETs on day 5 at POMA fertility clinic with positive live birth outcome. ML model, xgboost, was trained to predict multiple live birth (N = 54) versus single live birth (N = 139). Detailed embryology data from day 1 to day 5 were used as input.

Participants/materials, setting, methods

Input of the machine learning model included patient age and 18 morphological parameters collected on days 1, 2, 3 and 5 (symmetry, number of cells, blastocyst status, fragmentation, ICM and troph grades) from the two transferred embryos. An xgboost algorithm was trained on 80% of the data (n = 154) and tested on 20% of blind data (n = 39).

Main results and the role of chance

Xgboost machine learning algorithm predicted multiple live birth on the blind dataset with an accuracy of 72%, with an AUC of 0.60, showing better results than random. PPV (true prediction of multiple births) was 64% and NPV (true prediction of single birth) was 75%.

The following parameters ranked high in the predictive power of the machine learning (in order of predictive power): blastocyst status on day 5 of both embryos, symmetry on day 3, number of cells on day 2, scores on day 2 and 3. Limitations, reasons for caution: The dataset was derived from a single clinic with manual annotations and may not be transferable to other clinics. The risk of bias is important as the model was trained only àon embryos that were transferred and led to at least one birth

Wider implications of the findings: A tool to help identify which patients are at increased risk of MP with MET would be clinically useful to help patients and clinical team make the best personalised decision for a specific embryo, finding the balance between maximising success rate whilst minimising multiple pregnancy rate and its associated risks.

Trial registration number

Not applicable

POS0373 LIRAGLUTIDE HAS POTENT ANTI-INFLAMMATORY AND ANTI-CATABOLIC IN VITRO ACTIVITIES IN OSTEOARTHRITIS

Background:

Osteoarthritis (OA) is an age-related joint disease which provokes chronic pain and limits mobility. The disease progression is associated with inflammatory responses and cartilage degradation. Both chondrocytes, the only cell type present in cartilage, and macrophages from the synovium, play a major role in OA pathophysiology. Liraglutide is a Glucagon-Like Peptide-1 Receptor (GLP-1R) agonist widely prescribed for the treatment of type 2 diabetes. Interestingly, anti-inflammatory properties of the GLP-1 pathway have been reported in various diseases outside diabetes.

Objectives:

We evaluated the anti-inflammatory and anti-catabolic effects of Liraglutide in two in vitro models relevant to OA by evaluating surrogate markers of inflammation, cartilage matrix proteolysis and differentiation.

Methods:

Lipopolysaccharide (LPS)-stimulated murine Raw 264.7 macrophages were treated with 10 concentrations (6.6nM-3.4µM) of Liraglutide for 24h. Anti-inflammatory activity was evaluated by the production of nitric oxide (NO) and prostaglandin E2 (PGE2) using Griess reaction and ELISA, respectively. Interleukin 1β (IL-1β)-stimulated mouse articular chondrocytes were treated with Liraglutide (6.6nM-3.4µM) for 24h. Production of IL-6, matrix metalloproteinase-3 (MMP-3) and glycosaminoglycans (GAG) was measured by ELISA and GAG assay, respectively. RTqPCR analyses were performed with three selected concentrations of Liraglutide (13.3nM, 53.1nM and 1.7µM) on both cell types to assess the expression of a panel of genes related to inflammation (IL-6, TNF, iNOS), M1/M2 macrophage phenotype (MCP-1, CD38, ERG-2), catabolism (MMP-13, ADAMTS-5) and differentiation (Sox9, Col2a1, Acan).

Results:

Liraglutide induced a dose-dependent inhibition of the LPS-induced production of NO (IC50=45nM) and PGE2 (IC50=54nM) in macrophages. Moreover, IL-6 and TNF gene expressions were significantly and dose-dependently decreased in Raw 264.7 cells treated with Liraglutide compared to LPS alone. Interestingly, there was a significant dose-dependent reduction of MCP-1 and CD38 (M1 marker) gene expression in cells treated with the 3 doses of Liraglutide compared to LPS alone while we observed a dose-dependent increase of ERG-2 (M2 marker) gene expression induced by Liraglutide. Liraglutide significantly dose-dependently reduced the IL-1β-induced release of IL-6 (IC50=38nM), MMP-3 (IC50=56nM) and GAG (IC50=47nM) in chondrocytes. Additionally, Liraglutide treatment dose-dependently decreased the IL-1β-induced gene expression of iNOS, MMP-13 and ADAMTS-5. Finally, IL-1β decreased gene expression of Sox9, Col2a1 and Acan differentiation markers, which was rescued in a dose-dependent manner by Liraglutide (Table 1).

Table 1.

Gene expression results (fold change) in Raw 264.7 murine macrophages or mouse primary articular chondrocytes

Cell typeMarkersVehicleVehicleLiraglutide (nM)13.353.11700Macrophages- LPS+ LPSIL61.0±0.2*63.6±7.158.8±6.536.3±8.4*30.8±2.6*TNFα1.0±0.2*26.8±4.917.5±2.6*9.5±1.8*4.1±2.1*MCP11.1±0.6*91.7±11.267.8±4.3*47.3±6.1*25.1±5.5*CD381.1±0.6*103.5±22.373.2±12.3*44.6±8.9*17.4±3.3*ERG21.0±0.3*0.3±0.11.1±0.5*2.1±0.6*3.1±0.2*Chondrocytes- IL1β+ IL1βiNOS1.0±0.2*47.8±17.634.2±15.518.9±8.2*11.8±2.9*MMP131.0±0.2*9.8±2.07.6±1.04.6±0.7*2.5±0.4*ADAMTS51.2±0.82.7±0.62.0±0.61.6±0.31.1±0.2Sox91.0±0.1*0.4±0.20.4±0.20.6±0.00.7±0.2Col2a11.0±0.2*0.3±0.10.3±0.10.5±0.30.8±0.3*Acan1.2±0.8*0.2±0.10.1±0.00.5±0.1*0.7±0.2*

* p<0.05 vs LPS or IL1β alone, n=4

Conclusion:

A shift in M1/M2 macrophage phenotype and the inhibition of chondrocyte expression of several mediators involved in inflammation and cartilage degradation explain, at least in part, our previous results from rodent osteoarthritis models that showed an analgesic, anti-inflammatory and anti-degradative effect of Liraglutide. The fact that Liraglutide is already safely prescribed in another indication allows us to foresee a first trial in humans in the short term.

Acknowledgements:

All the people who contributed to the InOsteo project: the members of 4P-Pharma, INSERM UMRS_938 research team, SATT Lutech and Sorbonne University

Disclosure of Interests:

Francis Berenbaum Consultant of: Boehringer, Bone Therapeutics, CellProthera, Expanscience, Galapagos, Gilead, GSK, Merck Sereno, MSD, Nordic, Novartis, Pfizer, Regulaxis, Roche, Sandoz, Sanofi, Servier, UCB, Peptinov, 4P Pharma, 4Moving Biotech, Grant/research support from: TRB Chemedica, Coralie Meurot Employee of: 4P-Pharma, Laure Sudre Employee of: 4P-Pharma, Keren Bismuth Employee of: 4P-Pharma, Revital Rattenbach Shareholder of: 4P-Pharma, Employee of: 4P-Pharma, Patrice Denefle Speakers bureau: 4P-Pharma, Consultant of: 4P-Pharma, Pierre Fabre, Mimetas, Employee of: 4P-Pharma, Celine Martin Employee of: 4P-Pharma, Claire Jacques: None declared

Sustained effect of two antioxidants (oxothiazolidine and δ-tocopheryl glucoside) for immediate and long-term sun protection in a sunscreen emulsion based on their different penetrating properties

OBJECTIVE

We investigated the dermal bioavailability and antioxidative properties of a sunscreen formulation containing two antioxidants, oxothiazolidine (OTZ) and δ-tocopheryl glucoside (DTG). OTZ reacts directly with reactive oxygen species to form taurine, while DTG is metabolized in δ-tocopherol to achieve antioxidative activities.

METHODS

After topical application to a hair follicle-derived reconstructed human epidermis (RHE) model, followed by solar-simulated radiation, kinetics of bioavailability and antioxidative responses were measured over 24 h. Markers for oxidative stress were malondialdehyde (MDA), superoxide dismutase (SOD) and catalase activities.

RESULTS

The two antioxidants had different bioavailability profiles: OTZ was rapidly and extensively absorbed, whereas DTG was slowly absorbed and converted to δ-tocopherol. Compared to OTZ alone, the protection against effects on MDA levels and SOD and catalase activities was higher when DTG was used alone or in combination with OTZ. When used in combination, the degree of protection increased over time and remained constant over 24 h with maximal protection 2 h post-irradiation. DTG slowly penetrated into the skin and was present in the skin at all post-irradiation timepoints, thus allowing a slow but constant supply of δ-tocopherol over at least 24 h. By contrast, the oxidative protection by OTZ was immediate but short-lived due to its rapid penetration through the RHE and into the receptor fluid.

CONCLUSION

These results indicate a complementary sunlight protective action of OTZ and DTG with an immediate delivery of OTZ just after topical application of the formulation, and a prolonged skin delivery of δ-tocopherol from the slower penetration and metabolism of DTG.

THU0055 ANTI-DEGRADATIVE AND PRO-CHONDROGENIC PROPERTIES OF LIRAGLUTIDE, A GLUCAGON-LIKE-PEPTIDE 1 RECEPTOR AGONIST: EVIDENCE FROM PRECLINICAL STUDIES AND IMPLICATION FOR OSTEOARTHRITIS

Background:

Osteoarthritis (OA) is a degenerative joint disease affecting millions of individuals worldwide. Its development has been reported to be associated with cartilage degradation and inflammatory responses leading to pain, swelling and reduced function. Although OA is a disorder of the whole joint, the progressive destruction of cartilage extracellular matrix is considered as its hallmark. To date, approved OA treatments are only symptomatic. Therefore, there is an urgent need to explore disease-modifying OA drugs (DMOADs) that can mitigate, stop, or even reverse the development of OA.

Objectives:

In this context, the objective of this study was to assess the effect of liraglutide, a Glucagon-Like-Peptide 1 Receptor (GLP-1R) agonist approved for type 2 diabetes, on chondrogenesis, catabolism/inflammation and cartilage protection inin vitroandin vivopreclinical models of OA.

Methods:

The capacity of liraglutide to induce chondrogenesis was evaluated using primary human mesenchymal stem cells (hMSCs). Alcian blue staining was used to assess differentiation of hMSC into chondrocyte spheroids. IL-1β-stimulated mouse articular chondrocytes were treated with different concentrations of liraglutide for 24h. Production of matrix metalloproteinase MMP-13, prostaglandin E2 (PGE2) and nitrite was measured by ELISA and Griess reaction, respectively. Exendin 9-39, a GLP-1R antagonist, was used to confirm target engagement in thein vitroexperiments. Intra-articular (IA) injections of liraglutide or vehicle were performed in the type II collagenase rat model. Histopathological analyses (OARSI scores1) were conducted blindly by one investigator.

Results:

Liraglutide induced the differentiation of hMSCs into chondrocytes. Indeed, 21 days after differentiation initiation, 5/6 and 4/6 alcian-blue positive spheroids were observed for 10 and 100nM liraglutide, respectively, versus 0/6 for vehicle. Liraglutide significantly reduced dose-dependently the IL-1β-induced production of PGE2 (5808±178 for vehicle vs 4560±140, 2933±171 and 2365±85 pg/ml for liraglutide 10, 100 and 500nM, respectively, p≤0.001), nitrite (24.9±0.4 for vehicle vs 20.9±1.5, 19.1±0.9 and 16.5±0.5 µM for liraglutide 10, 100 and 500nM, respectively, p≤0.001) and MMP-13 (686±9 for vehicle vs 553±3, 402±5 and 297±8 pg/ml for liraglutide 10, 100 and 500nM, respectively, p≤0.001) in murine chondrocytes. Effects of liraglutide were GLP-1R dependent since exendin 9-39 significantly counteracted both chondrogenesis and inflammation/catabolism markers expression. Histological assessment of rat collagenase-injected knee joint revealed a significant (p≤0.05) decrease of the total joint score in the IA Liraglutide treated group (8±4) compared to vehicle (11±4).

Conclusion:

Liraglutide induced chondrogenesis, decreased metalloproteinase and inflammatory mediators production by chondrocytes and protected cartilage inin vitroandin vivopreclinical OA models, opening the way for repositioning this drug as a potential DMOAD.

References:

[1]Osteoarthritis Cartilage. 2010 Oct;18 Suppl 3:S24-34

Acknowledgments:

All the people who contributed to the InOsteo project: the members of 4P-Pharma, INSERM UMR S938 research team, SATT Lutech and Sorbonne University

Disclosure of Interests:

Francis Berenbaum Grant/research support from: TRB Chemedica (through institution), MSD (through institution), Pfizer (through institution), Consultant of: Novartis, MSD, Pfizer, Lilly, UCB, Abbvie, Roche, Servier, Sanofi-Aventis, Flexion Therapeutics, Expanscience, GSK, Biogen, Nordic, Sandoz, Regeneron, Gilead, Bone Therapeutics, Regulaxis, Peptinov, 4P Pharma, Paid instructor for: Sandoz, Speakers bureau: Novartis, MSD, Pfizer, Lilly, UCB, Abbvie, Roche, Servier, Sanofi-Aventis, Flexion Therapeutics, Expanscience, GSK, Biogen, Nordic, Sandoz, Regeneron, Gilead, Sandoz, Coralie Meurot Employee of: 4P-Pharma, Jerome Breton Employee of: 4P-Pharma, Laure Sudre: None declared, Carole Bougault: None declared, Revital Rattenbach Shareholder of: 4P-Pharma, Employee of: 4P-Pharma, Celine Martin Employee of: 4P-Pharma, Claire Jacques: None declared

Activation of innate immunity by 14-3-3 ε, a new potential alarmin in osteoarthritis

OBJECTIVE

The innate immune system plays a central role in osteoarthritis (OA). We identified 14-3-3ε as a novel mediator that guides chondrocytes toward an inflammatory phenotype. 14-3-3ε shares common characteristics with alarmins. These endogenous molecules, released into extracellular media, are increasingly incriminated in sustaining OA inflammation. Alarmins bind mainly to toll-like receptor 2 (TLR2) and TLR4 receptors and polarize macrophages in the synovium. We investigated the effects of 14-3-3ε in joint cells and tissues and its interactions with TLRs to define it as a new alarmin involved in OA.

DESIGN

Chondrocyte, synoviocyte and macrophage cultures from murine or OA human samples were treated with 14-3-3ε. To inhibit TLR2/4 in chondrocytes, blocking antibodies were used. Moreover, chondrocytes and bone marrow macrophage (BMM) cultures from knockout (KO) TLRs mice were stimulated with 14-3-3ε. Gene expression and release of inflammatory mediators [interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNFα)] were evaluated via reverse transcription quantitative polymerase chain reaction (RT-qPCR) and ELISA.

RESULTS

In vitro, 14-3-3ε induced gene expression and release of IL6 and MCP1 in the treated cells. The inflammatory effects of 14-3-3ε were significantly reduced following TLRs inhibition or in TLRs KO chondrocytes and BMM.

CONCLUSIONS

14-3-3ε is able to induce an inflammatory phenotype in synoviocytes, macrophages and chondrocytes in addition to polarizing macrophages. These effects seem to involve TLR2 or TLR4 to trigger innate immunity. Our results designate 14-3-3ε as a novel alarmin in OA and as a new target either for therapeutic and/or prognostic purposes.

Identification of lipids of the stratum corneum by high performance thin layer chromatography and mass spectrometry

The stratum corneum, the outermost layer of the epidermis, is the most important skin barrier against exogenous physical and chemical effects, in addition to protecting against dehydration. Ceramides are integral parts of the intercellular lipid lamellae of the stratum corneum and play an important role in the barrier function of mammalian skin. Ceramides are sphingolipids consisting of sphingoid bases linked to fatty acids by an amide bond. Typical sphingoid bases in the skin are composed of dihydrosphingosine, sphingosine, phytosphingosine, and 6-hydroxysphingosine, and the fatty acid acyl chains are composed of non-hydroxy fatty acid, α-hydroxy fatty acid, ω-hydroxy fatty acid, and esterified ω-hydroxy fatty acid. Analytical methods, such as gas chromatography/mass spectrometry, high performance thin layer chromatography with UV detection, and liquid chromatography/mass spectrometry, have been developed for the identification and quantification of ceramides in the stratum corneum. However, only a few publications relate to the mass fragmentation patterns specific to ceramide types to determine the structure of skin ceramides. Moreover, these studies provide very limited structural information and only for some ceramides. Therefore, the aim of our study was to develop a quick and easy method of quantification of ceramides, cholesterol, and free fatty acids by high performance thin layer chromatography with ultraviolet detection. High performance thin layer chromatography with ultraviolet detection was also coupled with mass spectrometry using negative ionization by electrospray and tandem mass spectrometry (MS/MS) for identification of ceramides' structure.

Characterization of xenobiotic metabolizing enzymes of a reconstructed human epidermal model from adult hair follicles

In this study, a comprehensive characterization of xenobiotic metabolizing enzymes (XMEs) based on gene expression and enzyme functionality was made in a reconstructed skin epidermal model derived from the outer root sheath (ORS) of hair follicles (ORS-RHE). The ORS-RHE model XME gene profile was consistent with native human skin. Cytochromes P450 (CYPs) consistently reported to be detected in native human skin were also present at the gene level in the ORS-RHE model. The highest Phase I XME gene expression levels were observed for alcohol/aldehyde dehydrogenases and (carboxyl) esterases. The model was responsive to the CYP inducers, 3-methylcholanthrene (3-MC) and β-naphthoflavone (βNF) after topical and systemic applications, evident at the gene and enzyme activity level. Phase II XME levels were generally higher than those of Phase I XMEs, the highest levels were GSTs and transferases, including NAT1. The presence of functional CYPs, UGTs and SULTs was confirmed by incubating the models with 7-ethoxycoumarin, testosterone, benzo(a)pyrene and 3-MC, all of which were rapidly metabolized within 24h after topical application. The extent of metabolism was dependent on saturable and non-saturable metabolism by the XMEs and on the residence time within the model. In conclusion, the ORS-RHE model expresses a number of Phase I and II XMEs, some of which may be induced by AhR ligands. Functional XME activities were also demonstrated using systemic or topical application routes, supporting their use in cutaneous metabolism studies. Such a reproducible model will be of interest when evaluating the cutaneous metabolism and potential toxicity of innovative dermo-cosmetic ingredients.

Love of Animals and Interpersonal Affectionate Behavior

The relationship between humans' affectionate behavior with other humans and with animals was investigated. 149 adults (81 current pet-owners and 68 nonowners) completed the two affection scales of Schutz's 1966 FIRO-B and Ray's Love of Animals questionnaire. Current pet owners scored higher on Love of Animals than nonowners, who in turn scored higher than those that had never owned a pet. Factor analysis of the Love of Animals Scale gave a large factor (Attitudes Towards Pet Ownership) and a smaller one (Value of Animals). No relationship was found between Wanted or Expressed Affection and either of the Love of Animals factor scores once sociodemographic factors were partialled out. No differences were found between pet-type for Wanted or Expressed Affection. It is concluded that there is no support for a relationship between affection for animals and interpersonal affectionate behavior, at least for casual pet-owners.

Effect of skin metabolism on dermal delivery of testosterone: qualitative assessment using a new short-term skin model

The skin is a metabolically active organ expressing biotransformation enzymes able to metabolize both endogenous molecules and xenobiotics. We investigated the impact of metabolism on the delivery of testosterone through the skin with an ex vivo pig ear skin system as an alternative model for human skin. Penetration, absorption and metabolic capabilities were investigated up to 72 h after application of [(14)C]-testosterone doses of 50-800 nmol on either fresh or frozen skin, with the latter model being metabolically inactive. Testosterone absorption and metabolite production were monitored by radio-HPLC and gas chromatography-mass spectrometry. Testosterone absorption through frozen skin was much lower, irrespective of the dose of testosterone applied, compared to fresh skin. Using fresh skin samples, >95% of the radioactivity recovered in culture media, as well as the skin itself, corresponded to metabolites. These results were compared with the metabolic data obtained from other in vitro systems (liver and skin microsomes). The present work leads to the conclusion that most of the enzymatic activities expressed in liver fractions are also expressed in pig and human skin. The metabolic activity of the skin can modulate the biological activity of pharmaceuticals (and xenobiotics). Consequently, it can also greatly affect transdermal drug delivery.

A potential role of chondroitin sulfate on bone in osteoarthritis: inhibition of prostaglandin E₂ and matrix metalloproteinases synthesis in interleukin-1β-stimulated osteoblasts

OBJECTIVES

To determine the effect of chondroitin sulfate (CS) on inflammatory mediators and proteolytic enzymes induced by interleukin-1β (IL-1β) and related to cartilage catabolism in murine osteoblasts.

DESIGN

Osteoblasts were obtained by enzymatic digestion of calvaria from Swiss mice and cultured for 3 weeks as a primary culture. Cells were then stimulated with IL-1β (1 or 10 ng/ml). CS-treated osteoblasts were incubated with 100 μg/ml of CS during the last week of culture w/o IL-1β for the last 24 h. Expressions of cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), 15-PG dehydrogenase (15-PGDH), matrix metalloproteinases-3 and -13 (MMP-3 and -13), osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa B ligand (RANKL) were determined by real-time polymerase chain reaction (PCR). PGE₂, MMP-3 and MMP-13 release were assessed in the medium by enzyme-linked immunosorbent assay or western-blotting.

RESULTS

IL-1β increased COX-2, mPGES-1, MMP-3, MMP-13, RANKL expressions, decreased 15-PGDH expression, and increased PGE₂, MMP-3 and MMP-13 release. Interestingly, 7 days of CS treatment significantly counteracted IL-1β-induced expression of COX-2 (-62%, P<0.001), mPGES-1 (-63%, P<0.001), MMP-3 (-39%, P=0.08), MMP-13 (-60%, P<0.001) and RANKL (-84%, P<0.001). Accordingly, IL-1β-induced PGE₂, MMP-3 and MMP-13 releases were inhibited by 86% (P<0.001), 58%(P<0.001) and 38% (P<0.01) respectively.

CONCLUSIONS

In conclusion, our data demonstrate that, in an inflammatory context, CS inhibits the production of PGE₂ and MMPs. Since CS has previously been shown to counteract the production of these mediators in chondrocytes, we speculate that the beneficial effect of CS in Osteoarthritis (OA) could not only be due to its action on cartilage but also on subchondral bone.

Viable skin efficiently absorbs and metabolizes bisphenol A

Skin contact has been hypothesized to contribute to human exposure to bisphenol A (BPA). We examined the diffusion and metabolism of BPA using viable skin models: human skin explants and short-term cultures of pig ear skin, an alternative model for the study of the fate of xenobiotics following contact exposure. 14C-BPA [50-800 nmol] was applied on the surface of skin models. Radioactivity distribution was measured in all skin compartments and in the diffusion cells of static cells diffusion systems. BPA and metabolites were further quantified by radio-HPLC. BPA was efficiently absorbed in short-term cultures, with no major difference between the models used in the study [viable pig ear skin: 65%; viable human explants: 46%; non-viable (previously frozen) pig skin: 58%]. BPA was extensively metabolized in viable systems only. Major BPA metabolites produced by the skin were BPA mono-glucuronide and BPA mono-sulfate, accounting together for 73% and 27% of the dose, in pig and human, respectively. In conclusion, experiments with viable skin models unequivocally demonstrate that BPA is readily absorbed and metabolized by the skin. The trans-dermal route is expected to contribute substantially to BPA exposure in human, when direct contact with BPA (free monomer) occurs.

Use of the γH2AX assay for assessing the genotoxicity of polycyclic aromatic hydrocarbons in human cell lines

The development of in vitro genotoxic assays as an alternative method to animal experimentation is of growing interest in the context of the implementation of new regulations on chemicals. However, extrapolation of toxicity data from in vitro systems to in vivo models is hampered by the fact that in vitro systems vary in their capability to metabolize chemicals, and that biotransformation can greatly influence the experimental results. Therefore, much attention has to be paid to the cellular models used and experimental conditions. Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic ubiquitous pollutants. Human exposure to PAHs is mainly from food origin. In this study, a detailed analysis of the biotransformation capabilities of three human cell lines commonly used for in vitro testing (HepG2, ACHN and Caco-2) was undertaken using 3 model PAHs (benzo(a)pyrene [B(a)P], fluoranthene [FLA] and 3-methylcholanthrene [3-MC]). Concomitantly the genotoxicity of these PAHs was investigated in different cell lines, using a new genotoxic assay (H2AX) in 96-well plates. The metabolic rates of B(a)P, FLA and 3-MC were similar in HepG2 and Caco-2 cell lines, respectively, though with the production of different metabolites. The ACHN cell line was shown to express very limited metabolic capabilities. We demonstrated that the PAHs having a high metabolic rate (B(a)P and 3-MC) were genotoxic from 10(-7) molar in both HepG2 and Caco-2 cells. The present study shows that H2AX measurement in human cell lines competent for the metabolism, is an efficient and sensitive genotoxic assay requiring less cells and time than other currently available tests.