Advancements in non-invasive skin sampling: Clinical conditions characterization via the assessment of skin surface cytokine biomarkers

The skin is increasingly recognized as a biological active organ interacting with the immune system. Given that the epidermal skin layer actively releases various cytokines, non-invasive skin sampling methods could detect these cytokines, offering insights into clinical conditions. This study aims non-invasively measuring cytokine levels directly from the skin surface to characterize different inflammatory chronic disorders in the adult and elderly population: psoriasis, diabetes type 2, rosacea, chronic kidney disease (CKD) and aging. Cytokines IL-1β, IL-8 and IL-10 were sampled from healthy subjects and patients aged 18-80 using skin surface wash technique. A well with sterile phosphate-buffered saline solution was placed on the skin for 30 min, and the extracted solution was collected from the well for further cytokine levels analysis using ELISA assay. Results show distinct cytokine profiles in different pathological processes, healthy controls, affected and unaffected areas. Aging was associated with increased IL-1β, IL-8, and IL-10 levels in skin. In diabetes, IL-1β and IL-8 levels were elevated in lesional areas, while IL-10 levels were decreased in non-lesional skin. Psoriatic lesions showed elevated levels of IL-1β and IL-8. Rosacea patients had lower IL-10 levels in both lesional and non-lesional areas. CKD patients exhibited significantly lower IL-10 levels compared to healthy individuals. In conclusion, skin surface wash-derived cytokine profiles could serve as "alert biomarkers" for disease prediction, enabling early detection. Additionally, this method's cost-effectiveness allows pre-screening of molecules in clinical studies and holds potential as a tool for biomarkers and omics analysis, enhancing disorder characterization and disease management.

Cutaneous Nrf2-Keap1 pathway modulation by environmental factors: The Dead Sea area as a test case

The skin is constantly exposed to exogenous environmental stressors and has to cope with excessive oxidative stress and tissue damage. However, exposure to moderate environmental stressors may be beneficial for the cutaneous tissue and assist in protecting against oxidative damage via the enhanced activation of the nuclear factor erythroid 2-related factor 2-Kelch-like ECH-associated protein 1 (Nrf2-Keap1) pathway. Such moderate stressors can be found in various locations around the globe. In this manuscript, we chose to focus on the Dead Sea (DS) area as a test case to study the effect of moderate stressors on the cutaneous tissue because of the unique combinations of moderate stressors in this area. The exceptional location of the DS at an altitude of -438 meters below sea level (the lowest place on earth) is responsible for its rare accumulation of moderate stressors such as high-water salinity, high atmospheric pressure, and unique solar radiation. In this manuscript, we hypothesized that the unique solar radiation in the DS area generates moderate oxidative stress in the skin leading to the induction of intracellular electrophiles, which in turn can activate the protecting Nrf2-Keap1 pathway. We showed that exposure of human skin organ culture from the same donor to solar radiation at the DS resulted in significant activation of the Nrf2-Keap1 pathway, induction of phase II enzymes, and lower apoptotic activity compared to a nearby location at a higher altitude (Jerusalem +700 m). This remarkable effect of activating the Nrf2 protecting pathway and the importance and characteristics of the solar irradiation at the DS is discussed.

eDNA-Mediated Cutaneous Protection Against UVB Damage Conferred by Staphylococcal Epidermal Colonization

The human skin is a lush microbial habitat which is occupied by a wide array of microorganisms. Among the most common inhabitants are Staphylococcus spp., namely Staphylococcus epidermidis and, in ≈20% of healthy individuals, Staphylococcus aureus. Both bacteria have been associated with cutaneous maladies, where they mostly arrange in a biofilm, thus achieving improved surface adhesion and stability. Moreover, our skin is constantly exposed to numerous oxidative environmental stressors, such as UV-irradiation. Thus, skin cells are equipped with an important antioxidant defense mechanism, the Nrf2–Keap1 pathway. In this work, we aimed to explore the morphology of S. aureus and S. epidermidis as they adhered to healthy human skin and characterize their matrix composition. Furthermore, we hypothesized that the localization of both types of bacteria on a healthy skin surface may provide protective effects against oxidative stressors, such as UV-irradiation. Our results indicate for the first time that S. aureus and S. epidermidis assume a biofilm-like morphology as they adhere to ex vivo healthy human skin and that the cultures’ extracellular matrix (ECM) is composed of extracellular polysaccharides (EPS) and extracellular DNA (eDNA). Both bacterial cultures, as well as isolated S. aureus biofilm eDNA, conferred cutaneous protection against UVB-induced apoptosis. This work emphasized the importance of skin microbiota representatives in the maintenance of a healthy cutaneous redox balance by activating the skin’s natural defense mechanism.

A157 REAL-WORLD TIGHT OBJECTIVE MONITORING WITH ADALIMUMAB LEADS TO EARLIER DOSE OPTIMIZATION AND HIGHER CLINICAL REMISSION RATES AT 12 MONTHS

Background

Data suggests that tight objective monitoring of inflammatory bowel diseases (IBD) may improve one-year clinical outcomes.

Aims

The goal of this study is to assess the adherence to serial tight objective monitoring, via clinical symptoms and biomarkers, and the effect of such tight monitoring on one year outcome in IBD patients at an academic and an university-affiliated center.

Methods

We retrospectively reviewed the chart of 428 consecutive IBD patients who started adalimumaby at the McGill University Health Center and Jewish General Hospital (Montreal, Canada) between January 1, 2015 and January 1, 2019 [338 Crohn’s disease(CD), 90 ulcerative colitis(UC)]. Clinical symptoms (assessed by Harvey-Bradshaw-Index and partial Mayo), C-Reactive Protein(CRP), and fecal calprotectin(FCAL) were captured at treatment initiation and at 3, 6, 9, and 12 months. Combined adherence was defined as the evaluation of ≥2 of 3 parameters(clinical, CRP, FCAL). Dose optimization and drug sustainability curves were plotted by Kaplan-Meier method.

Results

Clinical symptoms were assessed in nearly all patients at 3 (CD-UC:95-94%), 6 (90-83%), 9 (86-85%) and 12 (96-89%) months. CRP was also available for most patients but the frequency of assessment decreased in CD patients over the study period. In comparison, compliance to serial FCAL testing was low throughout the follow-up period. Clinical remission at one-year was significantly higher in patients who were adherent to early assessment visit at 3 months (p=0.001 both for CD and UC). Adherence to early follow-up also resulted in earlier dose optimisation in both CD and UC patients(pLogrank=0.026 for UC and p=0.09 for CD). However, the overall drug sustainability did not differ.

Conclusions

Clinical assessment and CRP, but not FCAL, were frequently assessed in patients starting adalimumab. Adherence to early objective combined follow-up visits resulted in earlier dose optimization and improved one-year clinical outcomes but did not change drug sustainability rates.

Funding Agencies

None

The Cutaneous Physiological Redox: Essential to Maintain but Difficult to Define

Skin is a unique tissue, possessing extremely efficient protective and regulative mechanisms, similar only to the gut and lungs. These tissues serve as an interface with the environment and are exposed to stressors from both endogenous and exogenous sources. Interestingly, all these stressors lead downstream to a cellular production of reactive oxygen species (ROS) and other electrophiles, which, in turn could have deleterious outcomes for the living organism. Hence, such tissues should always maintain a “high-alert” condition in order to cope with these various insults. Nevertheless, a moderate production of ROS induced by stressors could actually be beneficial, although it is impossible to predict if and which exposure would lead to which outcome. Consequently, a parameter which would indicate the skin’s readiness to cope with continuously fluctuating conditions is required. It has been proposed that the redox status may serve as a suitable indicator. In this opinion manuscript, we argue that the redox status is a vague parameter that is difficult to characterized and quantify due to its extremely dynamic nature. The common convention that the redox status is composed solely of the balance between oxidants and reductants (ROS and antioxidants) is also thought-provoking. Since this parameter in vivo behaves in a dynamic and complex manner, it better fits the description of a process, rather than an individual parameter. We suggest that the homeostatic modulation of the physiological redox (PR) should be in focus, rather than the redox status parameter itself. It is further suggested that low molecular weight antioxidants (LMWA) are, in fact, rather insignificant concerning the PR maintenance, and that the major contributors to this delicate modulation are regulative, protein-based systems such as the protective phase II antioxidant enzymes. Moreover, we show that skin microbiome and cutaneous advanced lipid peroxidation end-products (ALEs) take part in sustaining the cutaneous PR homoeostasis via activation of the Nrf2–Keap1 protective pathway.

Saturated and aromatic aldehydes originating from skin and cutaneous bacteria activate the Nrf2-keap1 pathway in human keratinocytes

Skin homeostasis is constantly challenged by environmental factors, affecting its delicate redox balance. The skin is also home to a wide variety of bacterial species, including Staphylococci. The cutaneous redox state is governed by the Nrf2-keap1 pathway, which is responsible for the induction of phase II cytoprotective enzymes, thus sustaining a healthy oxidative state. As part of normal metabolism, both bacteria and cutaneous tissue emit copious amounts of volatile organic compounds (VOCs), one subgroup of which are aldehydes. α,β-unsaturated aldehydes are known activators of Nrf2-keap1 pathway by direct oxidation of the keap1 protein. However, we did not encounter reports of Nrf2 activation by saturated or aromatic aldehydes, neither bacteria nor skin-derived. We hypothesized that non-α,β-unsaturated aldehydes derived from skin or cutaneous bacteria may act as Nrf2-keap1 pathway activators and therefore afford protection against environmental insults. The saturated aldehydes nonanal and decanal (known skin metabolites) and the aromatic aldehyde benzaldehyde (known skin and Staphylococcus epidermidis metabolite) were shown to induce the Nrf2-keap1 pathway in human keratinocytes. We also identified a newly described aromatic aldehyde, 3-furaldehyde (3-FA), emitted from S. aureus and S. epidermidis cultures, which also activated the pathway. Moreover, Nrf2-keap1 induction led to a significant protection against UVB-induced apoptosis. The mechanism involved in this activation has been partially elucidated. This work emphasizes the importance of cutaneous bacteria, as well as healthy skin lipid peroxidation processes in the maintenance and regulation of the cellular antioxidant response, namely with regard to coping with environmental stressors.

A232 EFFICACY OF TOFACITINIB FOR THE TREATMENT OF MODERATE-TO-SEVERE ULCERATIVE COLITIS: REAL-WORLD DATA

Background

A significant proportion of patients with moderate to severe ulcerative colitis (UC) do not respond to therapy, which includes thiopurines, glucocorticoids, and antagonists to tumour necrosis factor-α and integrin. Tofacitinib, a Janus Kinase inhibitor, has emerged as an efficacious and safe treatment for moderate to severe ulcerative colitis. However, it is not known if this efficacy translates into real-life effectiveness in a regular clinical practice.

Aims

We aimed to assess the rate of clinical response and clinical remission at 3 and 6 months after tofacitinib initiation. Secondary endpoints included rate of biomarker normalization, corticosteroids-free clinical remission and severe infections.

Methods

We conducted a multi-center retrospective observational study of adult patients with active UC started on tofacitinib from January 1, 2015 to October 1, 2019 at the McGill University Health Center and Hotel-Dieu de Lévis. A positive clinical response was defined as a decrease of ≥3 in the partial Mayo score. Clinical remission was defined as partial Mayo score of ≤2. Biomarker normalization was defined as fecal calprotectin ≤250ug/g. Severe infection was defined as an infection requiring hospitalization.

Results

During the study period, 40 patients with UC were started on tofacitinib. Amongst the patients, 85% (n=34) had failed ≥1 biologic and 50% (n=20) had failed ≥3 biologics. At the time of this preliminary analysis, 38 patients had undergone 3 months of treatment and 30 patients had undergone 6 months of treatment. At 3 months, a clinical response was seen in 89.5% of patients (n=34) and clinical remission occurred in 63.2% (n=24). At 6 months, clinical response occurred in 73.3% of patients (n=22) and clinical remission was sustained in 53.33% (n=16). Biochemical normalization occurred in 29.0% (n=11) and 30.0% (n=9) at 3 and 6 months, respectively. Additionally, 63.2% (n=24) and 43.3% of patients (n=13) achieved steroid-free clinical remission at 3 and 6 months, respectively. In the interim, one patient developed a serious infection requiring discontinuation of drug.

Conclusions

Our preliminary analysis demonstrates that in a real-life setting, tofacitinib is an effective treatment for inducing clinical remission in refractory UC patients. Further data will be complied to better assess the efficacy over a longer follow up.

Funding Agencies

None

Chronic treatment with Tempol during acquisition or withdrawal from CPP abolishes the expression of cocaine reward and diminishes oxidative damage

In previous studies, we reported that pretreatment with the antioxidant Tempol attenuated the development and expression of cocaine-induced psychomotor sensitization in rats and diminished cocaine-induced oxidative stress (OS) in the prefrontal cortex (PFC) and nucleus accumbens (NAc), suggesting a potential role for Tempol in interfering with cocaine-related psychomotor sensitization. The aim of the current study was to examine the role of Tempol in reward and reinforcement using the conditioned place preference (CPP) paradigm. We found that administration of Tempol during the conditioning session abolished the expression of cocaine-induced CPP. We also found that OS was significantly elevated following the establishment of CPP, and that cocaine-induced OS was significantly diminished by pretreatment with Tempol during conditioning. Furthermore, we found that repeated, but not single, administration of Tempol for seven days during withdrawal from CPP resulted in significant attenuation in the expression of CPP. Moreover, Tempol did not affect the expression of food reward. Taken together, these findings provide evidence for the involvement of Tempol in regulating cocaine rewarding properties without affecting natural rewards. Since Tempol was found to be effective in reducing OS and expression of CPP following withdrawal, it may be a potential treatment for cocaine addiction.

A novel role of topical iodine in skin: Activation of the Nrf2 pathway

For a long time iodine has been used as an active dermal agent in the treatment of inflammatory, immune-mediated and infectious diseases. Moreover, topical iodine application has been reported to provide protection against sulfur-mustard-induced skin lesions, heat-induced and acid-induced skin burns in both haired guinea-pigs and mouse ear swelling models. However, the exact mechanism of action underlying these benefits of iodine has not yet been elucidated. In the current study, a novel mechanism of action by which iodine provides skin protection and relief, based on its electrophilic nature, is suggested. This study demonstrates that both iodine and iodide are capable of activating the Nrf2 pathway in human skin. As a result, skin protection against UVB-induced damage was acquired and the secretion of pro-inflammatory cytokines (IL-6, IL-8) from LPS-challenged skin was reduced. Iodide role in the enhanced activation of this pathway is demonstrated. The mode of action by which iodine and iodide activate the Nrf2 pathway is discussed.

The bright side of plasmonic gold nanoparticles; activation of Nrf2, the cellular protective pathway

Plasmonic gold nanoparticles (AuNPs) are widely investigated for cancer therapy, due to their ability to strongly absorb light and convert it to heat and thus selectively destroy tumor cells. In this study we shed light on a new aspect of AuNPs and their plasmonic excitation, wherein they can provide anti-oxidant and anti-inflammatory protection by stimulating the cellular protective Nrf2 pathway. Our study was carried out on cells of the immune system, macrophages, and on skin cells, keratinocytes. A different response to AuNPs was noted in the two types of cells, explained by their distinct uptake profiles. In keratinocytes, the exposure to AuNPs, even at low concentrations, was sufficient to activate the Nrf2 pathway, without any irradiation, due to the presence of free AuNPs inside the cytosol. In contrast, in macrophages, the plasmonic excitation of the AuNPs by a low, non-lethal irradiation dose was required for their release from the constraining vesicles. The mechanism by which AuNPs activate the Nrf2 pathway was studied. Direct and indirect activation were suggested, based on the inherent ability of the AuNPs to react with thiol groups and to generate reactive oxygen species, in particular, under plasmonic excitation. The ability of AuNPs to directly activate the Nrf2 pathway renders them good candidates for treatment of disorders in which the up-regulation of Nrf2 is beneficial, specifically for topical treatment of inflammatory skin diseases.

The role of the catecholic and the electrophilic moieties of caffeic acid in Nrf2/Keap1 pathway activation in ovarian carcinoma cell lines

In recent years, numerous studies have demonstrated the health benefits of polyphenols. A major portion of polyphenols in western diet are derived from coffee, which is one of the most consumed beverages in the world.

It has been shown that many polyphenols gain their beneficial properties (e.g. cancer prevention) through the activation of the Nrf2/Keap1 pathway as well as their direct antioxidant activity. However, activation of Nrf2 in cancer cells might lead to resistance towards therapy through induction of phase II enzymes.

In the present work we hypothesize that caffeic acid (CA), a coffee polyphenol, might act as an electrophile in addition to its nucleophilic properties and is capable of inducing the Nrf2/EpRE pathway in cancer cells.

The results indicate that CA induces Nrf2 translocation into the nucleus and consequently its transcription. It has been demonstrated that generated hydrogen peroxide is involved in the induction process. It has also been found that this process is induced predominantly via the double bond in CA (Michael acceptor). However, surprisingly the presence of both nucleophilic and electrophilic moieties in CA resulted in a synergetic activation of Nrf2 and phase II enzymes.

We also found that CA possesses a dual activity, although inducing GSTP1 and GSR, it inhibiting their enzymatic activity.

In conclusion, the mechanism of induction of Nrf2 pathway and phase II enzymes by CA has been elucidated. The electrophilic moiety in CA is essential for the oxidation of the Keap1 protein. It should be noted that while the nucleophilic moiety (the catechol/quinone moiety) can provide scavenging ability, it cannot contribute directly to Nrf2 induction. It was found that this process may be induced by H₂O₂ produced by the catechol group.

On the whole, it appears that CA might play a major role in the cancer cells by enhancing their resistance to treatment.

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The electrophilic moiety in CA is essential for the oxidation of the Keap1 protein.

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The nucleophilic moiety contribute to Nrf2/Keap1 activation via production of H₂O₂.

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CA possesses a dual activity, as inducer and as inhibitor of GSTP1 and GSR1.

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The effect of coffee on healthy subjects and cancer patients may be different.

Can nitroxides evoke the Keap1-Nrf2-ARE pathway in skin?

Nitroxides are stable cyclic radicals of diverse size, charge, and lipophilicity. They are cell-permeative, which effectively protects cells, tissues, isolated organs, and laboratory animals from radical-induced damage. The mechanisms of activity through which nitroxides operate are diverse, including superoxide dismutase-mimetic activity, oxidation of semiquinone radicals, oxidation of reduced metal ions, procatalase-mimetic activity, interruption of radical chain reactions, and indirect modulation of NO levels. Nitroxides possess both a nucleophilic (reducing properties) and an electrophilic (oxidizing properties) nature and, therefore, they may affect different cellular pathways. In the current study, a novel mechanism of action by which nitroxides provide skin protection based on their electrophilic nature is suggested. This study shows that nitroxides may act as electrophiles, directly or indirectly, capable of activating the Keap1-Nrf2-ARE pathway in human keratinocytes (HaCaT) and in human skin (human organ culture model). The high potency of oxoammonium cations versus hydroxylamines in activating the system is demonstrated. The mechanism of action by which nitroxides activate the Keap1-Nrf2-ARE pathway is discussed. Understanding the mechanism of activity may expand the usage of nitroxides as a skin protection strategy against oxidative stress-related conditions.

Transcriptome profiling of human hippocampus dentate gyrus granule cells in mental illness

This study is, to the best of our knowledge, the first application of whole transcriptome sequencing (RNA-seq) to cells isolated from postmortem human brain by laser capture microdissection. We investigated the transcriptome of dentate gyrus (DG) granule cells in postmortem human hippocampus in 79 subjects with mental illness (schizophrenia, bipolar disorder, major depression) and nonpsychiatric controls. We show that the choice of normalization approach for analysis of RNA-seq data had a strong effect on results; under our experimental conditions a nonstandard normalization method gave superior results. We found evidence of disrupted signaling by miR-182 in mental illness. This was confirmed using a novel method of leveraging microRNA genetic variant information to indicate active targeting. In healthy subjects and those with bipolar disorder, carriers of a high- vs those with a low-expressing genotype of miR-182 had different levels of miR-182 target gene expression, indicating an active role of miR-182 in shaping the DG transcriptome for those subject groups. By contrast, comparing the transcriptome between carriers of different genotypes among subjects with major depression and schizophrenia suggested a loss of DG miR-182 signaling in these conditions.